Using PI660 Version 8 An Operator s Guide To Data Acquisition Using The Pacific Instruments Model 6000 DAS

Transcription

1 Using PI660 Version 8 An Operator s Guide To Data Acquisition Using The Pacific Instruments Model 6000 DAS

2 Conventions Used In This Manual When discussing pictures or screen captures from PI660 this manual will use a circle with a number in it to refer to an area or control that the user should refer to when reading about a certain feature. The circle figure is shown below. 1 Each circle figure is actually a hyperlink that allows the user to click the circle and automatically move to the section of text that describes the area. 2

3 Introduction Version 8.1 of PI660 for the 6000 DAS includes a variety of new features. Among the new features is the ability to acquire data simultaneously from multiple input sources. Version 8.1 includes support for the ICS-610 and ICS-645 high-speed sigma-delta digitizer boards. Each ICS-610 has the ability to digitize up to 32 channels of analog signals at a rate of 100,000 samples per second per channel. Each ICS-645 has the ability to digitize up to 32 channels of analog signals at a rate of 2,500,000 samples per second per channel. The PI660 software currently supports up to 10 of the ICS boards per system. Most of the standard interface screens for PI660 were rewritten as part of the Version 8.0 update. Steps To Success Using PI660 can be as simple or as complex as the user s test requires. The reader of this manual in encouraged to start slowly, and to get to know the features he absolutely needs to use before diving into the advanced features of the PI660 software. A solid understanding of the basic operational concepts of the 6000 system and the PI660 software is a must before learning about the more advanced features. The following table lists the operations capable with PI660. Operation Purpose Required Performed System Configuration Tell PI660 what types of signal conditioning and digitization modules are to be used in this system Yes When system is originally installed, or when cards are moved inside of the 6000 enclosure. Typically performed only when the system is installed Test Channel Selection Tells PI660 which inputs to sample in the test Yes Whenever inputs need to be added to or removed from the test. Channel Definition Sample Rate Definition Manage Data Files Export Data Files Test File Saving Recording Options Definition Preview Data Tells PI660 how each channel should be named, what type of measurements the channels will make, etc. Tells PI660 how fast to sample each channel in the test. Channels can be sampled at different rates. Allows the user to view raw data files in any directory on the PC s disk drives. Further, this allows the user to delete, export, view, or copy files to other locations on the network. This operation allows the user to go directly to the export screens that he could have spawned using the Manage Data Files operation. Saves all the information pertainant to the system setup in a file. The file can be reloaded at any future time. Allows the user to specify the method by which PI660 will switch from streaming data without recording it (Previewing) to disk to streaming data with recording to disk (Recording). Also allows the user to specify rearming options for multiple recordings Instructs the 6000 system to begin sampling while the software receives, converts, and displays the data. Data Yes Yes Yes Yes Yes. Yes Yes Whenever the user needs to adjust a channel s measurement characteristics. When the user needs to adjust the sample rate for any or all channels. Typically data acquired are exported to formats for viewing, plotting, or analysis. PI660 supports a number of data export formats, and the user will want to do this operation often. Typically data acquired are exported to formats for viewing, plotting, or analysis. PI660 supports a number of data export formats, and the user will want to do this operation often. Whenever the user desires. Generally not done often. Very often 3

4 Stop Acquisition Record Data Create Data Displays Modify Data Displays Automatic Zero Clear Counters Enable/Disable Simulator Setup 6028 Input Channel Commands Readiness Review are not recorded to raw files in this mode Instructs the 6000 system to stop sampling data. Instructs the 6000 system to begin sampling while the software receives, converts, and displays the data. Data are recorded to raw files in this mode Allows the user to create displays that display data. Currently PI660 offers Text, Bar, Strip Chart, XY, High Speed XY, Scope, Spectrum, Bitmap Picture, Dynomometer, Background Trace, Digital I/O, 3-D waterfall, and Campbell diagram displays. The user can create as many displays as he desires and individually setup the displays as necessary. All displays are completely independent and fully customizeable. Each data display can be customized to include different channels, colors, etc. Right mouse clicking over a display instructs PI660 to show the properties dialog for the display. The user uses the properties dialog to customize the display. Allows PI660 to instruct the 6000 system s channels to perform an automatic zero. Automatic zero removes amplifier offset due to temperature drift. Allows PI660 to instruct any 6048 channels that are in a counter mode to clear their internal counters PI660 has a simulator mode that allows its data displays to show some simple data even when there is no 6000 system connected to the computer The 6028 is a high speed digitizer only channel board. PI660 can route signal conditioning setup commands to a Pacific 9355 or Pacific 5500 signal conditioning subsystem connected to 6028 input channels. Allows PI660 to show a dialog box that synopsizes the operations that still need to be performed prior to executing a test. The user can customize the readiness review to include synopsis Yes Yes Yes Yes No No No No No Very often Very often Performed often. Performed often. Automatic zero is performed automatically for the user every time he sends channel settings to an analog channel in the 6000 system. Only performed on counter channels, and then only when the user desires to zero the counters Please make sure simulator mode is disabled prior to trying to setup or use a 6000 system. Only performed one time, and only performed by users owning both 6028 channel modules and either a 9355 or 5500 analog signal conditioning subsystem. Performed by the discriminating user to ensure he has done everything he needs to do prior to executing a test. 4

5 Fire Switch Definition Strain Gage Setup Manage Information Files Manage Raid Files Report Gallery Set Playback Position/Select Playback File Set Digital Outputs Set Voltage Output (DAC) Set Current Output (DAC) Setup Voltage DAC Replay information about most critical functions. Allows the user to tell PI660 which input channel is to be used to denote time zero in the captured data. Allows the user to enter gage resistance, gage factor, line resistance, and full scale micro strain deflection. Upon receiving this information PI660 suggests a maximum gain for the channel(s) by calculating theoretical gage output for full scale compression and tension PI660 creates a number of different files while the user is operating the software. The information files, as they are known, are text files that contain reports about operations that the user carries out with the software. Data for the ICS high speed digitizer cards is stored on a Raid subsystem. PI660 allows the user to extract the data from this subsystem. The Raid subsystem uses a proprietary file format and the contents of the Raid are not viewable using Windows Explorer Allows the user to create a text export file of the voltage calibration, engineering unit calibration, channel setup information, and record/time zero signal setups. Allows the user to playback data previously acquired from raw files to the current set of data displays. Allows the user to set or review the output bits of any digital output channels in his test Allows the user to set voltage output levels on the output lines of the optional PC based DAC card. Allows the user to set current (I) output levels on the output lines of the optional PC based DAC card. Allows the user to map test channels into DAC output lines so that when data are replayed the DAC output voltages mimic the voltages read by the analog input No No No No No No No No No No As a default PI660 will consider the beginning of a data file to be time zero. If the user wants an event in the file to be denoted as time zero (when the data are exported) then he will want to setup the Fire Switch definition. Fire switch means time zero. Only when using strain gages. Not necessary as the user can enter the gain directly. This is a helper tool. Information files are generated automatically. The user can choose to view, delete, edit, or ignore the files. The files are generally named such that the name includes the test name, time, and date that the operation was performed. The information files create a paper trail about what was done leading up to the performance of a test. Only users with ICS high-speed digitizer boards will need to perform this task. This task is performed after one or more recordings. It allows the user to move data from the Raid to the local disk in the format of a PI660 raw data file. A raw data file on the local disk is essential for data export and archiving operations. Performed periodically to create files of setup information that can be viewed easily with Excel. The user can replay the data after it is acquired. Typically, users export data in lieu of playback, but playback can be helpful in determining timing of different events that occurred in the test. Performed when testing out digital output connections. Can be performed when data is streaming. Performed when testing analog voltage output connections. Can be performed when data is streaming. Performed when testing analog current output connections. Can be performed when data is streaming. Performed when strip chart recorders are being used as an optional replay device. 5

6 Single Scan Record Replay Forward Replay Fast Forward Replay Reverse Replay Fast Reverse Pause Replay Set Replay Speeds channels. Instructs the PI660 software to record one sample from each channel in the test. Data are recorded to the current single scan file (a text file that is tab delimited). If PI660 is not in a Preview or Record mode it will initiate Preview for one scan and log the data. If it is Recording or Previewing PI660 will use the latest sample of data acquired for the single scan file. Instructs PI660 to start playing in forward the current playback file to the current data displays. If PI660 is already replaying in a different mode then the replay mode will switch to forward replay at the current data point being displayed. Instructs PI660 to start playing in fast forward the current playback file to the current data displays. If PI660 is already replaying in a different mode then the replay mode will switch to fast forward replay at the current data point being displayed. Instructs PI660 to start playing in reverse the current playback file to the current data displays. If PI660 is already replaying in a different mode then the replay mode will switch to reverse replay at the current data point being displayed. Instructs PI660 to start playing in fast reverse the current playback file to the current data displays. If PI660 is already replaying in a different mode then the replay mode will switch to fast reverse replay at the current data point being displayed. Instructs PI660 to pause the playback of the current playback file. Pressing pause again causes playback to continue in the same mode. Allows the user to define the number of msec to wait between displaying the next point in forward and reverse playback modes. Also allows the user to define the number of points to skip over when playing back data in fast forward or fast reverse modes. No No No No No No No Performed when the user wants high speed display fidelity but only desires to capture small amounts of data for the channels. Typically used in configurations that use external triggering of the Ring Buffer for transient capture while data logging prior to the trigger event. Only when data replay to the screens is desired. Not valid when Previewing or Recording data. Only when data replay to the screens is desired. Not valid when Previewing or Recording data. Only when data replay to the screens is desired. Not valid when Previewing or Recording data. Only when data replay to the screens is desired. Not valid when Previewing or Recording data. Only when data replay to the screens is desired. Not valid when Previewing or Recording data. Only when data replay to the screens is desired. 6

7 Set Channel Input Modes Reset Channel Input Modes Manage Data Display Files Setup Computed Channels Compare Test Settings To Hardware Settings Allows the user to toggle the input modes of different channels. Input modes such as voltage calibration input, zero input, transducer input, input shunted, etc. are available depending on the card type of the channel. Instructs PI660 to tell the 6000 system to set all channel input modes to the normal transducer input mode. This is useful to help make sure that all channels are ready to acquire real test data. Collections of data displays can be saved to screen files (*.dsw). A dsw file is a text file, and the user can open, close, and save data display files at anytime. Allows the user to define mathematically computed channels. The computed channels are available for display and export. Up to 300 computed channels can be defined. Computations are based on the last values of the channels involved in the computations. Instructs PI660 to compare the test settings (gains, filters, alarms, etc.) to the actual hardware settings. Reports (text files) are generated that are named uniquely. The reports contain information about discrepancies and about actual hardware settings. No No No No No Typically performed when the user is trying to troubleshoot a channel or to verify engineering unit deflections for shunt resistors. PI660 uses the input modes during calibrations and always resets the input modes to transducer input when finished with an operation. This operation is performed only if the user desires to ensure transducer input mode is selected for all channels. Alternatively, the user can look at the CAL LED on each 6000 system rack and ensure transducer input mode is selected for all channels in each rack. If the CAL LED is illuminated on a rack then at least one channel in the rack is not in a transducer input mode. Users typically define display setups and then save them for future use. This way they don t have to recreate the displays. Advanced feature that is performed as the user desires. Performed by users desiring to catalog their test settings in a text fashion and desiring to ensure that the hardware setup matches the software setup. PI660 does not constantly poll the 6000 system, and can be used offline. So, it is possible for the user to have software settings that have not been sent to the hardware. PI660 tries to inform the user of this situation in many different areas of the software s operation. The user is encouraged to become aware of the fact that he needs to instruct PI660 to send changes to the hardware when he makes changes to the software settings. The user can completely define, setup, and perform a test using a subset of the operations listed in the above table. The rows marked as required are generally considered the minimal requirements for performing a test. 7

8 System Configuration The first step in using PI660 is to define the system configuration. The system configuration tells PI660 what types of digitizers and signal conditioners are available for use in the software. When PI660 is first run (after installation) it will ask if the user wants to automatically configure his Pacific 6000 system. It is generally a good idea to let PI660 do this. The PI660 software uses two types of hardware components. The components are data streams (digitizers) and signal conditioners. In versions prior to 8.0 PI660 only supported the Pacific Instruments models of digitizers (data streams) and signal conditioners. Now, however, the PI660 software supports two styles of data streams (digitizers) and four types of signal conditioners. The data streams supported include the Pacific Instruments model 6000 DAS, and the ICS-610 and ICS-645 sigma delta digitization boards and raid sub system. The signal conditioners supported include the full line of cards for the Pacific Instruments model 6000 DAS, the analog cards for the Pacific Instruments model 5500 DAS, the Pacific Instruments model 9355 high performance amplifier, and the National Instruments SCXI based frequency to voltage converters. PI660 also has support for the Pressure Systems, Inc. Model 9016 Net Scanner. Component Definitions The first step in system configuration is to define the components that the system has. Not all systems from Pacific Instruments will have the same components. The components available to PI660 depend upon the components purchased by the user s company. The different data stream components must be mapped into the PI660 software address space. This allows PI660 to discern between data sources (streams) for each channel in the system. Stream definitions, as they are known, are saved by the PI660 software when the user exits the software properly. For this reason there is no need to define the data streams more than one time for the software. The user of PI660 defines the system components using the system component definition utility. The following figure shows the system component definition utility. The utility is spawned using the System\Main System Definition\Define System Components menu item Figure 1. Component Definition Dialog Box In figure 1 six key areas are identified. The first area, indicated by the white circle with the number one in it, is a combo box that allows the user to control the total number of components that the software will be using. Currently the total number of components allowed is ten, but in reality most customers will only use one or two components. Area two in Figure 1 shows an edit box in which the user can place a name for each component. The name of a component is merely a text string associated with the component, but the user should note that the channel names in the 8

9 system address space will default to the component name followed by a dash and a number. For example, in the example above the channels in the system will default to have names Pacific DAS 1, Pacific DAS 2, etc. Area three in Figure 1 shows a combo box that allows the user to select the type of hardware that the component is made of. It is important to make this selection properly. The component type tells the software quite a bit about what the component is capable of. Area four in Figure 1 allows the user to define the total quantity of software addresses that this component will require. Alternatively, the control defines the number of channels that a component has. This last statement may seem confusing, but it should not be confusing when the reader considers a component that is a signal conditioner only and not a data source. In short, if a component supplies digital data then this control defines the number of software addresses that the component will use. If the component does not supply digital data then this control defines the number of signal conditioner channels that the component has. Area five in Figure 1 allows the user to tell the software if the component has a digitizer or not. The software requires the user to specify this so that the software can maintain flexibility as support for future components are added. If the user specifies that a component has a digitizer then the software will allow the user to define the software addresses that the digitizer component uses. Software address definition is discussed in the next section. Area six in Figure 1 allows the user to tell the software if the component has signal conditioning or not. The ICS-610 boards do have minimal signal conditioning, but the software does not support it at this point in time. Thus, the user should select no signal conditioning for all ICS-610 components. Signal conditioning for these components comes from either the Pacific Instruments signal conditioning product line or the National Instruments SCXI line of Frequency to Voltage converters. Defining The Software Address Space The second step in system configuration is to map the digitizer components (streams) into the PI660 software channel address space. The PI660 software provides an address space that supports up to 4096 channels. The user tells the software how to allocate the address space by using the stream definition utility. The user must allocate software address spaces to each component of the system that has a digitizer. In general this means Pacific Instruments 6000 card modules, ICS-610 & ICS-645 sigma-delta digitizer boards, and PSI Net scanners Figure 2. Software Address Space Allocation Dialog Box 9

10 Figure 2 shows the stream definition utility. The figure has several key areas identified. Area one in Figure 2 contains a combo box that allows the user to choose the component to allocate address spaces to. Component allocation is discussed in the previous section. Only components with digitizers will be visible in this combo box. Area two in Figure 2 contains a list box that shows the current software address space and the components allocated to the address space. An address that is not allocated to a component will show as Undefined. It is valid to allocate software addresses non contiguously. By this it is meant that one component can use software addresses one through 50 while the next component can use software addresses 120 through 195 for example. When the user high lights items in the list box the controls referenced in area three change to show how many addresses the user has high lighted, how many addresses are already defined for the component, and how many more addresses are required to be defined for the system. The user can allocate software addresses one at a time or in groups. When the user clicks the Allocate button referenced as area four of the figure above the current selections in the list box are allocated to the component selected in area one of the figure above. If the user tries to allocate too many software addresses for the component the software will provide an error message. There is no need to completely define a component. It is valid to leave a component partially defined. However, it seems that there would be little reason to do so. Digitizer Connections Once software address spaces have been allocated for the components the user needs to define the wiring between the signal conditioning components and the digitizer components. Pacific Instruments signal conditioning components are defined when software address spaces are allocated to the Pacific component. This is because of the fact that the signal conditioning components for the Pacific system are defined based on card type definitions. The following figure shows the main setup screen for digitizer wiring. Figure 3. Digitizer Connection Dialog Box In Figure 3 two distinct digitizer components are depicted. They are the Pacific DAS and the ICS-610-A. The left most column shows the name that the user gave the component when he defined the component. The second column shows the input channel of the component. The third column shows the software address associated with the digitizer 10

11 component channels. The fourth column shows the signal conditioner type currently associated with each digitizer input channel. The fifth column shows the rack, card, and card channel that is associated with the software address. The rack, card, card channel information is useful if the digitizer component is using Pacific signal conditioners. If the user clicks the right hand mouse button while the cursor is over a channel listing in the dialog box then he will see the following dialog box appear Figure 4. Signal Conditioner Connection Utility Dialog Box Certain controls in this dialog box will be disabled if the component being defined is a Pacific Instruments digitizing component. This is because of the fact that the Pacific Instruments digitizing components map one to one to the signal conditioners in the system. In figure 4 an ICS-610 digitizing board is having its input lines defined. If the ICS-610 board uses Pacific Instruments signal conditioning then the input signal conditioning channels for the board will map in a one to one fashion to the channels referenced by the address space associated with the ICS-610 board. For example, if the user defines the ICS-610 board to associate with software addresses and he chooses Pacific signal conditioning for the ICS-610 inputs zero through four then the Pacific Instruments signal conditioners at addresses 60, 61, 62, 63, and 64 will be allocated to the first five input lines of the ICS-610 board. This is a restriction on primary DAS systems (Backup systems are described later). Area one in Figure 4 shows the name of the digitizing component being wired. The user cannot change this entry. It is determined based on the channel that the user clicks the mouse over in the digitizer connections dialog box. It is for information purposes only. If the user wants to define inputs for another component then he needs to exit this dialog box and click another channel in the digitizer connections dialog box. Area two in Figure 4 contains a combo box that allows the user to select which input line for the digitizer component he is defining. Changing this selection will allow for the display of the currently defined connection for the input line. In the example above the first input line of this ICS-610 board is connected to a Pacific Instruments model 6033 strain card. Further, it is connected to the 6033 card in rack zero, card slot three, channel on card one. Area three in Figure 4 shows the information about the current connection. If the user changes the signal conditioning component for the input line the Signal Conditioning Channel combo box may become active (in the example above it is inactive). If the combo box becomes active then the user may choose a signal conditioning component channel for the digitizer input channel line. Area four in Figure 4 shows the repeat connection and disconnect buttons. A signal conditioner is connected to a digitizer when the user selects the signal conditioner channel using the Signal Conditioning Channel input line. If the user wants to automatically connect signal conditioning channels to digitizer channels he can click the Repeat Connection button. Clicking the Repeat Connection button automatically increments and connects the next digitizer input line with the next signal conditioner channel from the selected signal conditioning component. If the digitizer component does not allow redefinition of signal conditioning connections then the Repeat Connection button will not be active. Summary of System Configuration System configuration is typically only performed when there is new hardware to define for PI660. The settings of the system configuration are saved in the file StreamDefinitions.str in the PI660 working directory. These settings are read 11

12 every time PI660 is initiated, and they are stored anytime PI660 exits properly. There is an automatic configuration utility that can be used to configure the Pacific 6000 system component. The utility reads the cards in the 6000 system and allocates address space in the PI660 channel address map for all channels found. The user can review the configuration that resulted, add other components to his system, and complete a full system configuration. 12

13 Test Channel Selection When the user has defined the system configuration he is ready to select channels to include in his test. PI660 limits the channels displayed in most dialog boxes to only the channels the user has selected into the test. The user makes channel selections for the test using the dialog box shown in figure 5. The dialog box contains a number of active areas and controls that allow the user to navigate to other areas of system setup. Test channel selection is achieved by using the controls in area ten of figure 5. The other areas of figure 5 are discussed here as a convenience to the reader Figure 5. Test Channel Selection Dialog Box The select test channels dialog box has eight columns. It is in a spreadsheet format, and the channels listed in the dialog box are based on the system definitions the user made for software space allocation. A channel that is in the test is indicated by a large green check mark to the left of the channel name. A channel that is not in the test is indicated by no check mark in the first column. The names that are indicated in the first column come from user input. In the example above the user has already setup some channels for the test. If the user clicks the right hand mouse button above a channel name in the first column in this dialog box then the dialog box for setting up the channel information for the clicked channel will be shown. Area 10 of the dialog box allows for the addition and removal of channels from the test. Area two in figure 5 indicates status information about each channel. A large red exclamation point indicates that the software thinks that the channel information in the test file does not match the hardware channel information. A small green dot in this area means that the software thinks that the hardware should match the software settings for the given channel. Measurement type and units are discussed in the channel definition section. Area three in figure 5 lists the channel measurement type and units associated with the measurement. Measurement types are merely indicators of the measurement being made and have no affect on the conversion of data to engineering units. The same can be said of units. Measurement type and units are discussed in the channel definition section. If the channel s measurement type is Strain Gage then clicking the right mouse button over this area will spawn the Strain Gage Setup Dialog Box. Area four in figure 5 shows the measurement full-scale value in engineering units. Full scale values are used when calibration types are associated with channels. The number of digits after the decimal place indicates the number of digits that will be used when the software displays values from the channel. 13

14 Area five in figure 5 shows the status of the voltage calibration for the channel. Analog channels supported by the 6000 do not necessarily need periodic voltage calibration, and non-analog channels supported by the 6000 never need voltage calibration. Clicking the right hand mouse button over this column spawns the voltage calibration dialog box. Area six in figure 5 shows the status of the Engineering Unit calibration for the channel. Engineering Unit (EU) calibration is not necessary, but most users do choose to perform some sort of EU calibration for many channels. Clicking the right hand mouse button over this column spawns the EU calibration dialog box. Area seven in figure 5 shows the signal conditioning stream and channel type associated with the software address (channel). This information is generated when the system address space is allocated. Area eight in figure 5 points to the column that shows the sampling rates for each channel. This software defines all ICS- 610 and ICS-645 channels to have the same sample rate. So, when the user defines a sample rate for one ICS 610 channel he is defining the sample rate for all ICS channels in the test. Clicking the right hand mouse button while the cursor is above an entry in the sample rate column spawns the rate setup dialog box. It is discussed in a later section. Pacific Instruments channels can be sampled at different rates. If a channel is not included in the test (denoted by the lack of a green check mark in the first column) then its rate will be shown as zero. Area nine in the figure above allows the user to show either all available channels (based on the system address space setup) or only the channels in the test. Area ten includes several buttons that allow the user to add channels to the test or to remove channels from the test. Highlighted channels in the list box are affected by the user clicking the buttons in area ten. These buttons will not affect the system address space setup. Area eleven in figure 5 contains a button that allows the user to spawn the report gallery dialog box. The report gallery allows the user to generate text based reports of calibrations, channel setup, and sampling rates. The report gallery is discussed in a later section. Area twelve in figure 5 contains a button that when pressed spawns the voltage calibration dialog box. In the voltage calibration dialog box the user can perform voltage calibrations on the amplifiers in his system if he has an EDC 522 precision traceable voltage supply. For more information on voltage calibrations see either the section describing voltage calibrations or the section on performing voltage calibrations. Area thirteen in figure 5 contains a button that when pressed spawns the Engineering unit calibration dialog box. In the engineering unit calibration dialog box the user can perform engineering unit calibrations of his channels. The result of an engineering unit calibration is an equation that maps millivolts traceable (mv T ) to engineering units (EU). See the section on EU calibration for more information. Area fourteen in figure 5 contains a button that when pressed spawns the backup channel definition dialog box. In the backup channel definition dialog box the user defines which channels on the main system are backed up by the backup system. A backup system is one in which there are one or more ICS-610 high speed sigma delta conversion boards and a version of PI High Speed Backup software. See the section on backup systems for more information. Area fifteen in figure 5 contains a button that tells the software to highlight (select) all of the channels that are in the test that need downloading to the hardware. A red exclamation mark next to a channel in area 2 of the dialog box indicates a channel that needs downloading. This button is particularly useful if followed by a click on the button in area 16. Area sixteen in figure 5 contains a button that downloads the channels selected in the list box. The user can select channels using the shift and control keys on the keyboard along with a mouse click over the channels, or he can click the button in area thirteen of the above figure to have the software automatically select channels that have changed. Area seventeen in figure 5 contains two buttons that can be used to copy, move, or swap channel definitions. Often user s entering information about channel setup miss a channel definition or confuse a channel input with another. The copy and move/swap utilities spawn buttons wherein the user can alleviate mis-entered information or setup one channel and copy selected information from that channel to others. See the section on utilities for more information on how these two options operate. Area eighteen in figure 5 contains a button that can be used to save the current test settings. Test settings are saved in either a file with the extension.mdb or a file with the extension.tst. The.mdb file and the.tst file contain the same information, but the file formats are different. A.mdb file is a Microsoft Access database file, and a.tst file is a binary proprietary Pacific Instruments file format. The user can open one file type and save it as the other file type. No raw data are kept in these files. Only channel setup and scan list information along with calibration results and equations are saved in these files. It is a good idea to save your work often. Area nineteen in figure 5 contains a button that can be used to show the strain gage setup dialog box. The dialog box shows channels that the user has defined as strain gages and allows the user to enter values for line resistance, gage resistance, full scale micro strain, and gage factor. The software uses the values that the user enters to determine an optimum gain for the channel and can be used to download the channel settings for one or more channels. 14

15 Area twenty in figure 5 contains a button that can be used to show the automatic bridge balance dialog box. The automatic bridge balance dialog box is used on bridge type devices (1/4, ½, or full bridge) wherein the user desires to remove (via analog circuitry injection of voltage into the bridge output) the bridge s quiescent offset. Only channels with automatic bridge balance enabled (via the channel definition dialog box) will be listed on the automatic bridge balance dialog box. Area twenty-one in figure 5 shows if the channel is set for automatic export selection. Clicking the right mouse button over the column causes the channel(s) automatic export selection state to toggle. The user can add any acquired channel to the export list in the appropriate export utility dialog box. The automatic export selection setting for a channel is merely another of PI660 s convenient features. Area twenty-two in figure 5 shows a button that when pressed sends the sample rate information to all digitizer components in the system. Area twenty-three in figure 5 shows a button that when pressed will create a text file containing a report of the Pacific 6000 scan list. This report can be helpful in understanding how the data in the data packets coming from the 6000 system are organized. Typically, this button is only used for debugging purposes or to obtain a better understanding of the digital data packets coming from the 6000 system. Contact Pacific Instruments if you desire more information about the data packets. Area twenty-four in figure 5 contains a button that when pressed spawns the backup channel sample rate definition dialog box. See the section on backup systems for more information. Area twenty-five in figure 5 contains a button that when pressed spawns the Remote/Local F to V setup dialog box. Note, if the F to V channel you desire to setup is on the local machine it is not necessary to use this utility. Downloading the channel via the buttons in the Channel Definition dialog box is sufficient. If, however, the F to V is controlled by a network connected backup system you will need to use this utility. The F to V channels affected by this are the National Instruments SCXI F to V channels and not any F to V channel card modules developed by Pacific Instruments. Test Channel Selection Summary The dialog box in figure 5 contains quite a few controls and active areas. The user should only be concerned with area ten of the figure to achieve selecting test channels. The user should, however, become quite accustomed to coming to the Channel Selection dialog box to spawn other dialog boxes that allow him to setup other aspects of the data system and its channels. 15

16 Channel Definition Each channel that is included in the test must be defined before it is used. In the system address space phase of setup the user has told the software about the signal conditioning components of the system. This information determines what controls the software enables on the Channel Definition dialog box. The Channel Definition dialog box is shown below Figure 6. Channel Definition Dialog Box Figure 6 may seem ominous, but it is actually quite simple when you consider all of the signal conditioning modules that the Pacific Instruments model 6000 DAS supports. Each signal conditioning module for the 6000 system has different capabilities. When the user is defining a channel with this dialog box the controls that are not valid for the channel type will be inactivated by the software. Some of the controls are valid for each channel, and those controls will always be active. Area number one of the channel definition dialog box contains a combo box for selecting the channel number, an edit field for defining the channel name, and an area that shows the channel type. The combo box is used to move between channels during setup. Please note that area 29 in the above figure contains a button that allows the user to copy information from one channel to others. This should be used to speed setup of the channels used in the test. Also note that the information in this dialog box needs to be downloaded to the channel(s) before it is valid in the hardware. Area 25 contains the buttons associated with downloading to the hardware. Area 26 contains buttons associated with reading back information from the hardware and verifying that the software settings match the hardware settings. In area one the user can type in a function name for the currently selected channel. The function name can be up to 32 characters in length. Please take care to not use characters in the name that are invalid characters for Windows based file names. This is because of the fact that certain data export files are named using the channel name as part of the file name. Note that the channel names will be used (presented) in other dialog boxes in the software as the primary mechanism of selecting a channel to work on. Area two in the channel definition dialog box contains two edit fields denoted Description and Location respectively. These edit fields allow the user to enter extra textual information about each channel. They are filled in with default values when the channel address space is defined. Each edit field supports up to 32 characters of information. 16

17 Area three of the channel definition dialog box contains a combo box that allows the user to select the measurement type. The measurement type will define which standard units values are available in area seven of the dialog box. The user can use standard units or non-standard units. Typically, the units chosen are used only as a tag that is displayed along with the real time engineering unit converted data. Temperature measurements, however, do use the units chosen to determine the conversion to temperature algorithm for thermocouple type devices. Area four of the channel definition dialog box contains a bitmap image that indicates if the channel has been verified as matching the software setup. This indicator is only a best guess at the status of the software settings matching the hardware settings. It is only a best guess since the hardware subsystem and the software do not communicate every time the user changes a software setting. When the user downloads a channel (sends the settings to the channel) this indicator will display a green OK. The green OK indicates that the channel settings have been downloaded. The status of each channel is saved in the test file. Thus, the user should be cautious when he first opens a test file. This is since another test file may have been used since the user saved the test file, and the hardware settings may have been altered by using the other test file. Please note that hardware settings are restored automatically by the Pacific Instruments 6000 DAS when power is restored to the unit. A red exclamation point in the area four image indicates that the software thinks the hardware may have different settings from the software for the selected channel. Area five of the channel definition dialog box contains an edit field where the user enters the full scale engineering units value for the channel. The full scale value is used in conjunction with the standard calibration procedures to determine the associated engineering unit values for each calibration step for the channel. Please refer to the section on calibration setup for more information on this. The full-scale range also affects the number of digits after the decimal point that will be displayed for the channel s data. Entering will yield two digits of precision for example, and entering will yield four digits of precision. Further, the full-scale EU range is used for scaling graphical displays such as the oscilloscope display. Area six of the channel setup dialog box allows the user to select the gage type connected to the channel. In some cases the gage type selection will determine the positions of input switches on a channel card. Please refer to the documentation for each channel type for information about input switching. Gage type is very important to proper channel operation. The software will disable gage types that are not valid for a particular channel card type. If a user chooses a thermocouple gage type then the software will use internal look up tables to convert the channel data to temperature. Frequency counter timer gage types determine how the Pacific Instruments Model 6048 frequency counter timer card processes information. Generally speaking, if the user wants to ensure no automatic data conversion he should choose the Voltage gage type when available. Caution should be exercised here, though, since bridge completion for certain Pacific Instruments channel models is electrically switched in to place, and the user needs to choose the proper gage type (full bridge, half bridge, etc.) for bridge type gages. The same can be said for ICP gage types. Area seven of the channel setup dialog box allows the user to associate a units tag with the channel measurement. In most cases the measurement tag is merely a character string that is displayed along with the channel engineering unit converted data. The thermocouple type of gage does represent a different usage of the measurement units, however. The temperature scale (K, F, R, or C) determines how the software converts channel input data for thermocouple type gages. Standard units are pre-canned character strings that make units selection easier for the user. If the user wants to type in his own units tag he can clear the check box for the standard units (in area seven) and type in his units tag in the Non Standard Units edit field. Area eight of the channel setup dialog box allows the user to enable or disable the glitch catcher option for digital input channels. The glitch catcher option for the digital input instructs the digital input channel to catch short duration pulses and to hold them until the next sample clock occurs. This option ensures that transients are not missed when sampling a digital input at a rate slower than the transient itself. Area nine of the channel setup dialog box allows the user to determine the method used during engineering unit calibration for slope and offset determination. Two methods are available. They are least squares fitting, and two point straight line fitting. Please see the section on engineering unit calibration for more information on the distinctions between the two slope and offset determination mechanisms. Either mechanism will yield proper results. The two point straightline method performs certain operations that determine the best two points of the calibration to use when determining slope and offset. In version 8.1 and above area nine appears as shown in figure 7. Support for lookup tables was added to the software. 1 2 Figure 7. Version 8.1 Channel Definition Dialog Box Area 9 The user selects an engineering unit conversion style by selecting the type from the combo box shown in area 1 of figure 7. The EU conversion style can be either least squares fit, end point fit, or lookup table calculation. The conversion style tells PI660 how to calculate the slope and offset for the channel when performing an EU calibration (least squares or end 17

18 point calibration styles) and whether an engineering unit conversion equation or a lookup table will be used for calculating the EU value for the channel. The PI660 software uses the button shown in area 2 of figure 7 to allow the user to proceed to either the calibration information setup dialog box or the lookup table selection dialog box for the channel. Area ten of the channel setup dialog box allows the user to select the output filtering used on cards that allow programmable output filter selections. The model 6030 and the model 6120 of the Pacific Instruments product line have programmable output filtering. If the channel input is filtered (not wide band) then output filtering is available for each of the two outputs for the channel. If the user selects output filtering then the cutoff frequency of the output filter is the same as the cutoff frequency of the input. Area eleven of the channel setup dialog box allows the user to define an auxiliary input channel number for channels residing on a Pacific Instruments model 6028 high speed digitizer card. Auxiliary inputs indicate that the 6028 channels will use signal conditioning that resides in either a Pacific Instruments model 5500 or Pacific Instruments model 9355 signal conditioning system. Note, in Version 8.1 area eleven has been moved to the right hand side of the Channel Definition dialog box. Area twelve of the channel setup dialog box allows the user to enter the offset, slope, squared, and cubed coefficients for the engineering unit conversion equation. The slope and offset are automatically calculated for the user when he performs engineering unit calibrations. Engineering units equations are represented as offset in engineering units and slope in engineering units per mv referenced to input (RTI). Also in area 12 is a button with a question mark on it. Clicking the question mark button causes the following dialog box to appear. Figure 8. EU Conversion Equation Scale Factor Calculator The scale factor calculator is a tool that determines slopes and offsets used in engineering unit conversion based on information from a transducer data sheet. The user enters the engineering unit values and their equivalent mv or Ohms values. The software then calculates offset and slope based on the user s information. The user clicks the Use button to apply the equation to the channel. The software disables either Ohms or mv depending on the excitation voltage source for the channel. In version 8.1 the EU conversion equation controls will appear disabled for channels that use lookup table EU conversion. Area thirteen of the channel setup dialog box allows the user to modify the primary voltage conversion equation for the channel. The voltage conversion equation is normally begotten by performing a voltage calibration on the input channel modules via an EDC precision voltage calibrator. The user should not normally change this information. Area fourteen of the channel setup dialog box allows the user to select the amplification for the channel. The amplification is also known as the gain. Some Pacific Instruments signal conditioning models support variable gain. Area fourteen contains controls for selecting variable gain. In this version of the software variable gain is not fully implemented. Each model of the Pacific Instruments signal conditioners can have a different gain palette. The user selects gains to use on a per channel basis. The Pacific Instruments signal conditioners use an amplifier per channel architecture. The gain is set in the channel hardware when the user downloads the channel information to the channel hardware. 18

19 Area fifteen of the channel setup dialog box allows the user to select the filtering applied to the input signal by the channel module. Different channel module types have different filtering characteristics. Please refer to the documentation for each channel module type for further information. If a channel module type (ie 6033) only supports one hardware filter at a time (since the filter units are plug on units for the module type) the software can still represent more than one filter cutoff frequency. This ability is presented so that the user can track the cutoff frequency for each channel individually. For channel module types that have more than one hardware filter selection of the proper filter frequency determines which hardware filter the signal passes through prior to digitization. Filter information is sent to the channel when the channel information is downloaded. Area sixteen of the channel setup dialog box allows the user to enable or disable automatic zero for the channel. Automatic zero is a feature of the Pacific Instruments analog input channel module types. It ensures that each amplifier is re-zeroed when a channel gain or filter is changed. Normally, the user will leave this feature enabled. Automatic zero is one of the features that the Pacific Instruments model 6000 DAS employs to eliminate the need for potentiometers. The Pacific Instruments model 6000 DAS input modules are a no potentiometer zone. Enabling automatic zero does not instruct the channel to perform an automatic zero. An automatic zero of a channel is performed when the channel gain or filter is downloaded. It can also be performed by the user via the Selective Automatic Zero dialog box found in the calibration section of the main menu. Area seventeen of the channel setup dialog box allows the user to track whether or not AC coupling is used on the measurement channel. It does not programmatically enable AC coupling. AC coupling is enabled via the selection of ICP gage type in area six of the dialog box. Area eighteen of the channel setup dialog box allows the user to enable or disable automatic balance for each channel. Note, some channel types (6033 notably) have automatic balance that is enabled via hardware jumper for each channel. In this case, the enable automatic balance feature of the software simply tracks whether or not the user desires to have the channel represented in the dialog box that performs automatic balance. Automatic balance is the process of removing a bridge offset from a bridge type device. This is another area where the Pacific Instruments signal conditioning modules remove the need for potentiometers. The Pacific Instruments signal conditioning units have DACs on board that produce voltages that can be injected into the output of a bridge type device. The voltage to inject is determined when the user performs an automatic bridge balance on a channel. The channel firmware performs a successive approximation technique of varying the autobalance circuit output and reading the channel value. When the firmware determines that the DAC outputs have balanced the gage then the technique is finished. The DAC values are restored when the system is powered up. Area nineteen of the channel setup dialog box allows the user to tell the software the input attenuation used for model 6013 channels. The 6013 has a high voltage option that can be ordered. The high voltage option is user modifiable. This means that the user can change the attenuator for each channel. It is not recommended, however, since Pacific Instruments hand selects and trims the attenuator circuit at the factory. Area twenty of the channel setup dialog box allows the user to select the excitation type and level for each channel. The model 6033 signal conditioning module shares excitation level for each channel on the board. Thus only a single level is available for the eight channels on the board. The channels are individually regulated, so the reader should note that the level is shared but not the actual voltage lines. Excitation selections of current and voltage are available depending on the signal conditioning module. Excitation is not updated in the channel hardware until the user downloads the channel information to the channel. Excitation level is restored when the 6000 DAS powers up. Area twenty-one of the channel setup dialog box allows the user to select the excitation voltage sensing for channels that have programmable excitation sensing selection. Local sensing means that the excitation voltage level will be sensed and regulated at the card edge input connector. Remote sensing means that excitation voltage levels will be sensed and regulated at the gage. Remote sensing requires extra wires to be connected between the card and the transducer. Area twenty-two of the channel setup dialog box allows the user to setup information pertaining to model 6048 frequency counter timer modules. For more information on these features please see the document titled Understanding the Model 6048 Frequency Counter Timer. Area twenty-three of the channel setup dialog box allows the user to define further parameters for model 6048 frequency counter timer modules. The area also allows the user to select the frequency input range for National Instruments model 1320 SCXI Frequency to Voltage Channels. To select an input frequency range merely choose the proper range in the combo box. Area twenty-four of the channel setup dialog box allows the user to define the external control line usage for the counter mode of the model 6048 frequency counter timer modules. For more information on these features please see the document titled Understanding the Model 6048 Frequency Counter Timer. Area twenty-five of the channel setup dialog box allows the user to download channel parameters to an individual channel, multiple channels, or all channels. When performing a multiple channel download a dialog box appears that 19

20 allows the user to select the channels to download. As a result of properly downloading channels the status image in area four of the figure above will be updated. Area twenty-six of the channel setup dialog box allows the user to check the channel software settings against the channel hardware settings for an individual channel or all channels in the test. A status report will be created for each check. The status report is a text file that is named based on the current time and date. The user will immediately see the status report in the notepad program when the status report is complete. Note, it may take a bit of time for a status report to be prepared for large channel counts. Please be patient. Status reports are created in the current test directory. Area twenty-seven of the channel setup dialog box allows the user to setup engineering unit calibrations. Clicking the button in the area spawns the engineering unit conversion information dialog box. Engineering unit conversion is discussed in a later section of the manual. Please note that the selection the user makes in area nine of the dialog box will determine which controls the engineering unit conversion dialog box presents to the user. Area twenty-eight of the channel setup dialog box allows the user to setup the alarms associated with each channel. High and low alarm and warning limits may be associated with each channel, and colors that indicate good, warning, or alarm may be associated with each channel. Clicking the button in area twenty-eight spawns the alarm and warning definition dialog box. Area twenty-nine of the channel setup dialog box allows the user to copy information from one channel to others. Clicking the button spawns the copy information dialog box. Using this dialog box the user can selectively copy information between channels. This speeds test definition. Area thirty in the figure allows the user to select the temperature conversion reference that will be used. When determining thermocouple temperatures the software needs to know the reference junction temperature for the thermocouples. The software allows the user to use the model 6013 reference channel input and associated reference device as the source of the information concerning the reference temperature. It also allows the user to enter a single global temperature that is applied to all temperature conversions or to select a single input channel as the temperature input channel. Clicking the button in area thirty spawns the temperature reference channel setup dialog box. It is discussed later in the manual. Area thirty one of the channel setup dialog box contains a button that spawns the report gallery. The report gallery allows the user to generate text based reports about channel setup information. Area thirty two contains a save test button that allows the user to save the test information. Area thirty three contains a find channel button that spawns the find channel dialog box. If the user selects a new channel with the find channel dialog box then the Channel Setup Dialog box will reflect that change when the user closes the find channel dialog box. Summary of Channel Definition Channel definition is an important part of test preparation. Since the 6000 DAS supports a wide range of channel module types there are is a large number of controls shown on the channel definition dialog box. The user should get familiar with the controls, and he should understand the basic concepts of his channel modules to use the channel definition dialog box controls properly. The user should send the changed channel definitions to the 6000 system by downloading the settings to the channel(s). He should also refer to the Select Test Channels dialog box to ensure that the status shows OK and not the red exclamation bitmap (indicating the channel definition in the software quite possibly differs from the channel setup in hardware for a channel). Further, it is a good idea to save the test often during channel definition. 20

21 Sample Rate Definition Channel sample rates are specified using the Test Channel Selection dialog box (Figure 5). The PI660 software allows the user to define sample rates for channels when he adds channels to the test using the buttons in area ten of figure 5 or when he highlights a channel or channels in the Test Channel Selection dialog box and clicks the right hand mouse button over the sample rate column (area 8 of figure 5). Channels in the 6000 system are all sampled at the highest sample rate that the user selects for the 6000 system component. The PI660 software works with the 6000 system to decimate data for channels that require slower sample rates. PI660 uses a digital multiplexing architecture to decimate the data for slow speed channels. The digital muxing architecture shows up in channel sample rate selection. Channels can be sampled at the highest rate, ½, ¼, 1/8, 1/16, 1/1024 of the highest rate. To change a channel s sample rate or to set the system sample rate the user clicks the right hand mouse button over the sample rate column for the channel. If multiple channels are selected in the Test Channel Selection dialog box then the rates for all the selected channels will be affected by this operation. The dialog box shown in figure 9.is spawned when the user clicks the right hand mouse button over the sample rate column (area 8) of the Test Channel Selection dialog box for a channel that is a 6000 series channel. Figure 10 shows the dialog box spawned if the user clicks the right hand mouse button over the sample rate column for an ICS style of channel. 1 2 Figure 9. Channel Sample Rate Selection Two areas are of interest in the New Sample Rate dialog box (shown in Figure 9). They include a button in area one that spawns the Select Maximum Sample Rate dialog box and a combo box in area two that allows the user to select the sample rate for the channels highlighted in the Select Test Channels dialog box. The combo box in area two allows the user to select either the max rate, ½ the max rate, ¼ the max rate, etc. If the maximum sample rate for his test has already been selected (read on) then this combo box is the only control he will have to use to set the sample rate. Clicking the OK button causes PI660 to recalculate the scan list and to tell the user if his request is possible. There are some limitations to the digital multiplexing architecture, and PI660 will let the user know if he tries to exceed those limitations. A sample limitation is the aggregate sample rate limitation. Clicking the button in area 1 of the New Sample Rate dialog box (figure 9) spawns the dialog box shown in figure 10. Note, the dialog box shown in figure 10 is spawned directly for data stream components incapable of digital muxing and variable sample rates Figure 10. Max Sample Rate Selection Dialog Box 21

22 Area one of the Max Sample Rate Selection dialog box contains a combo box for selecting the data stream (digitizing component) for which the dialog box will set the rate. Changing the selection causes the sample rates available list box (area 2 in figure 10) to update with the possible rates for that digitizing component. Selecting a new sample rate in the list box (area 2 of figure 10) forces the actual rate read out control (area 4 of figure 10) to update with the new actual rate. The Pacific 6000 actual rate will match the rate selected in the list control. The rate of an ICS digitizing component will not match. This is since the ICS board rates are not whole numbers. They are very close, but the digitizing architecture does not allow for whole number sample rates. As a convenience PI660 displays the possible rates as whole number integer values in the rate selection list box. Sample Rate Definition Summary Sample rate selection is rather easy and straight forward. Different sample rates are allowed for different digitizing components. The 6000 digitizing component allows for different channels to be sampled at integer power of two divisions of the maximum system sample rate. Once the sample rates are defined the user should send the sample rates (download them) to the digitizing components by clicking the button indicated in area twenty-two of figure 5 (Test Channel Selection Dialog Box). 22

23 Preview Data When the user has defined the system components, selected test channels, defined the channels, specified sampling rates, and downloaded channel and sample rate information he is ready to use the data acquisition controls. The first control is the Preview control. It instructs PI660 to begin acquiring data from the 6000 system and to convert that data to EU values and to display that data. At this point in the manual we have not discussed EU conversion equations or data displays yet, so at this point the user will be viewing data that are converted using whatever equations he supplied to PI660 during the Channel Definition portion of this manual. PI660 can preview or record data without having data displays shown. Why someone would do this I don t know, so although it breaks a bit of the structure of this manual I will discuss one type of data display here. This way the reader of this manual can see data when he uses the preview button. Data displays are created by using the Screen\New Data Display menu item. If the user selects a tabular data display then he will get a text window data display that contains up to the first 20 channels that are selected into his test. Figure 11 shows a typical display, and figure 12 shows the properties dialog box for the display. Figure 11. Typical Tabular Data Display Figure 12. Properties Dialog Box For Tabular Display The properties dialog box for a data display is spawned when the user clicks the right hand mouse button over the data display. All data display properties dialog boxes contain list boxes showing the available channels (area 1 of Figure 12) and the channels selected into the data display (area 2 of Figure 12). The channels listed in the available channels list control include channels in the test (as selected using the Select Test Channels Dialog Box), Computed channels, in the case of the Tabular display type system status variables, and any user stream channels being used. User stream channels, and computed channels are discussed in later sections of this manual. 23

24 The user can add and remove channels from the display by either double clicking the channel names in the available or selected list controls (areas 1 and 2 of Figure 12) or by using the Add and Remove buttons (areas 3 and 4 of Figure 12) after highlighting channel names in the list controls. For this example some system status variables are added, and some unused channels are removed from the display. The resulting data display is shown in figure Figure 13. Tabular Display Setup Differently Figure 13 shows a tabular display snapshot that was acquired while PI660 was in a preview mode. Area 1 of the figure shows the system status variables. Area two points out that the same channel can be added to the display multiple times. This is helpful in the tabular display when the user wants to show the channel using different engineering units conversions for a channel. This aspect will be discussed in the section describing tabular data displays. In area 1 of figure 13 the Previewing system status variable is shown in green and its units are indicated as ON. To make the PI660 software start Previewing data the user simply clicks the Preview button on the PI660 button bar. The preview button is indicated by area one of figure Summary of Preview Data Figure 14. Preview Button Location Previewing data from the 6000 system can be done anytime the 6000 system has a scan list that matches that stored in the software. It can also be done when the lists do not match, but the results are not guaranteed and this is an illegal situation certainly fraught with peril. PI660 will instruct the user if it thinks the scan list in the hardware does not match the scan list in the software. The user is encouraged to take the advice of PI660 and download the scan list when told to do so. Downloading the scan list ensures that the hardware scan list and software scan list match. Previewing data means that data are streaming from the 6000 system to the PC. PI660 is managing that data streaming, and the data are not being recorded to disk. Data conversions are taking place, and the data displays are being updated. 24

25 Stop Acquisition When PI660 is streaming data from the 6000 system in Preview or Record modes the user may desire to stop the data streaming. The simplest way to stop streaming data from the 6000 system is to click the Stop button on the PI660 button bar. Figure 15 shows the location of the PI660 stop button. Please note, if the user clicks the Stop button while Record mode is active and the software responds with a message box indicating that the Stop Recording Mode Is Not Via Control Panel then the user should check the Recording Options Definition and make the Record Until option indicate Control Panel Stop. 1 Figure 15. Stop Button Location The Stop button is used to stop data acquisition from the 6000 system. It will stop recording and previewing. It will also stop playback of data from a raw data file. Area 1 of Figure 15 shows the stop button s location on the PI660 button bar. Summary of Stop Button The Stop button stops data streaming from all digitizer components. It stops Preview, Record, Single Scanning, and data playback from raw file. 25

26 Recording Options Definition PI660 has the capability to start recording data to disk in a number of different ways. It also has the capability to stop recording data to disk in a number of different ways. Before attempting to record data using PI660 the user should become familiar with the different possibilities for starting and stopping recording. Once he has setup recording options then he can continue with data recording activities. Table 2 indicates the ways that recording can be initiated. Table 3 indicates the ways that recording can be halted, and Table 4 indicates the two operations that PI660 can perform automatically when Recording stops. Record Start Method Control Panel Record Button Mark Bit Trigger Alarm Warning Meaning Recording starts when the user clicks the Record button on the PI660 tool bar. No external events can initiate recording. PI660 can be in a stopped mode or a previewing mode when the control panel record button is clicked and recording will start. The 6000 system has an external start line input on the master 6000 chassis. This line can be programmed to respond as a logic on condition when the input to the line is high or low. The mark bit logic on polarity setup is described in the section on Alarms and Triggers. If the user is using Mark Bit record start then PI660 must be in a Preview mode to start recording. PI660 looks at the status of the system Mark Bit in the header of each data packet and switches from Previewing to Recording when the Mark Bit is logically on when using Mark Bit Record Start Mode. The 6000 system Trigger is state is a logical OR of the possible Trigger input conditions. The Trigger state can be affected by channel alarms and warnings as well as by an external input line located at the back of the 6000 chassis. The Trigger line is not the same line as the Mark Bit line. The Trigger line can be programmed to respond as a logic ON condition when the input to the line is high or low. The Trigger line logic ON polarity setup is described in the section on Alarms and Triggers.. If the user is using Trigger record start then PI660 must be in a Preview mode to start recording. PI660 looks at the status of the system Trigger in the header of each data packet and switches from Previewing to Recording when the Trigger is logically on when using Trigger Record Start Mode. Please note that the Trigger state is a logical OR of external Trigger line input and any alarms or warnings that have been selected to source the Trigger state. Each input channel in a 6000 system has hardware based alarms and warnings. If they are enabled and setup then the channel(s) can set the state of the Alarm bus in the 6000 system. The 6000 Alarm bus is thus a logical OR of all channel alarm busses for channels that have the alarm enabled. If the user is using Alarm record start then PI660 must be in a Preview mode to start recording. PI660 looks at the status of the system Alarm in the header of each data packet and switches from Previewing to Recording when the Alarm is logically on when using Alarm Record Start Mode. Each input channel in a 6000 system has hardware based alarms and warnings. If they are enabled and setup then the channel(s) can set the state of the Warning bus in the 6000 system. The 6000 Warning bus is thus a logical OR of all channel alarm busses for channels that have the warning enabled. If the user is using Warning record start then PI660 must be in a Preview mode to start recording. PI660 looks at the status of the system Warning in the header of each data packet and switches from Previewing to Recording when the Warning is logically on when using Warning Record Start Mode. Table 2. Record Start Possibilities 26

27 Record Stop Method Control Panel Stop Button Time Expires No Mark Bit Meaning Recording stops when the user clicks the PI660 button bar Stop button. Recording stops when a specified number of seconds of data have been recorded. Note, PI660 will usually record slightly more than the number of seconds of data requested since the data packet size may not evenly divide into the number of seconds requested. The 6000 system has an external start line input on the master 6000 chassis. This line can be programmed to respond as a logic ON condition when the input to the line is high or low. The mark bit logic ON polarity setup is described in the section on Alarms and Triggers. PI660 looks at the status of the system Mark Bit in the header of each data packet and switches from Recording to Stopped Recording when the Mark Bit is logically OFF when using Mark Bit Record Stop Mode. Table 3. Record Stop Possibilities ReArm Stop After Recording Meaning Return to Preview mode. This makes the software capable of multiple recordings without further user interaction if one of the non-control panel Record Start methods are used. Stop acquiring data from the This means that the user will have to click either the Preview or Record button to initiate further acquisitions of data from the Table 4. After Recording Possibilities Combining the different Record Start, Record Stop, and After Recording Possibilities creates a wide range of recording options for the user. The user can perform all the tasks listed in table 5 and more. Recording Scenario Record Start Record Stop After Recording Operator wants to record data Control Panel Control Panel Stop and is willing to start and stop the recording using the control panel buttons. PI660 is to fully stop acquiring data at the end of each recording Operator wants to initiate a Control Panel Time Expires Stop timed recording using the control panel button, and he desires the data displays to stop after the timed record Operator wants to initiate a Control Panel Time Expires ReArm timed recording using the control panel button, and he desires the data displays to continue showing data after the timed record Operator wants to start Mark Bit No Mark Bit Stop recording on an external TTL start signal, and he wants the recording to stop when the signal is no longer present. No further data display updates are required when the recording stops. Operator wants to start recording on an external TTL start signal, and he wants the recording to stop when the signal is no longer present. Further, he wants to record a new run file each time the TTL Mark Bit No Mark Bit ReArm 27

28 signal becomes present. Operator wants to record a fixed amount of data when an external TTL signal becomes high. He wants to do this each time the signal becomes high, and he will ensure that the signal duration is less than the amount of time he wants to record. Mark Bit Time Expires ReArm Table 5. Some of the PI660 Recording Scenarios Recording Options Definition Summary The recording options provided by PI660 allow the user to start and stop recording in a number of different ways. The user should check the recording options prior to each test. This way he can ensure that he is ready to test. There has not yet been a user of PI660 that needed a record start and stop scenario that was not bounded by the options listed in Tables

29 Record Data When the user has selected the proper recording options he may start recording data with PI660. Data recording can be initiated by clicking the record button. Do not double click the record button. The record button has a toggle capability, and clicking the button when PI660 is recording causes recording to stop. This feature allows the user to quickly initiate recording and terminate recording if he is only interested in short recordings. The location of the record button on the PI660 button bar is shown in Figure Figure 16. Record Button Location Recording data creates a raw data file with the extension.raw. The name of the file created depends on the current test name, the current run number, and the digitizing component that the data is acquired from. Area 2 of figure 16 shows the currently active test file. Area 3 of Figure 16 shows the current run number. The name of the current test is determined when the user opens or saves a test file. The current run number is specified by the user using the Manage Data Files dialog box. The Manage Data Files dialog box is described in a later section. The user can also indicate to PI660 that it should automatically increment the run number after each recording. The name of the raw file created is the combination of information about the digitizing component, the test name, and the run number. Table 6 summarizes the file naming conventions for different digitizing components supported by PI660. Digitizing Component Raw File Naming Convention 6000 TnameRunN.raw 6000 Ring Buffer Data TnameRingRunN.raw ICS-610 Data TnameICSRunN.raw ICS-645 Data TnameICS645RunN.raw PSI NetScanner TnamePSIRunN.raw Where Tname = Test File Name Without Extension N = Current Run Number Table 6. Raw Data File Naming Conventions For example, if the user is executing the test file called c:\6000\demo\demo.tst using a 6000 system digitizer component and an ICS-610 digitizer component with run number being 22 then the following two files will ultimately be created. C:\6000\demo\demoRun22.raw C:\6000\demo\demoICSRun22.raw Containing 6000 system data Containing ICS-610 data The term ultimately is used above since the ICS data will first be recorded to Raid subsystem and the user must use the Manage Raid Files dialog box to transfer the ICS data from the Raid subsystem to the test directory. Managing Raid files is discussed in a later section of this manual. Once data are recorded the user can use the Manage Data Files Utility to export the raw data to a number of different formats. It is not generally a good idea to write software that interprets the raw data files created by PI660. This is due to the fact that the raw file format will change over time, and if the user receives an upgrade of PI660 it may create raw files that are incompatible with the code he has written for the earlier version raw files. The Manage Data Files Utility is discussed in a later section of this manual. Each raw data file contains all the information necessary to recreate the engineering unit converted data acquired. The raw file format includes raw data from the acquisition followed by what is known as a data stamp. The data stamp contains the conversion information for each channel acquired. The information includes all conversion equations, look up tables, channel names, units tags, etc. Record Data Summary 29

30 Recording data with PI660 can be achieved in a number of ways. The data are stored into uniquely named raw data files containing the.raw file extension. The user can export the data from the raw files using the Export Data Utilities described in the Manage Data Files section of this manual. Data from ICS products is stored on Raid, and that data must first be transferred to the local disk using the Manage Raid Files utility which is described in a later section of this manual. The user should not try to write software to interpret raw files since the contents of the raw files will change as new versions of PI660 become available. To insulate his software developments from changes in the raw file formats the user should write software to interpret files created by PI660 using the Export Utilities. Typically, users write code to interpret the binary engineering unit file export type. 30

31 Manage Data Files & Manage Raid Files When the user has recorded data the Manage Data Files and Manage Raid Files utilities can be used to access the files. ICS digitizing components store their data on a Raid subsystem during recording. The Raid subsystem does not have a Windows style of file system, so the contents of the Raid cannot be viewed using Windows Explorer. The user must use the Manage Raid Files utility to copy the file from the Raid to the local disk. The format of the data on the Raid is not the same as the format of the data on the local disk. PI660 adds test information to the Raid File when it is copied to the local disk. The information is the data stamp information. The user should transfer data from the Raid subsystem to the local disk after each recording. If he cannot do this he must ensure that the test settings (including voltage calibration equations and EU conversion equations, etc.) do not change between recordings. Manage Raid Files Figure 17. Raid Management Dialog Box Figure 17 shows the Manage Raid Files dialog box. Nine areas of interest are identified in the Figure. The Raid Management dialog box can be spawned using the Data\Manage Raid Files menu item. It shows the contents of the Raid subsystem. Files recorded to the Raid subsystem must be pre-allocated. PI660 performs the pre-allocation using the maximum recording time requested by the user and the current ICS component s sampling rate as the basis of determining how much Raid space to pre-allocate. The maximum recording time requested can be specified using the Reserve Disk Recording Space utility. This utility is discussed in a different section of this manual. Area one in figure 17 shows a column that lists the file indices. Raid files are accessed by PI660 using file index. Since PI660 uses file index to access files on the Raid it is not necessary for the file name (seen in the column referenced by area two in Figure 17) to be unique. Area three of Figure 17 contains information about the size and position of the Raid files on the Raid subsystem. For calculation purposes use 32 channels per ICS board, 4 bytes per ICS-610 channel, 2 bytes per ICS-645 channel, the number of ICS boards defined, the recording rate, and the recording time requested to calculate the expected size of the Raid file. PI660 forces all channels possible on the ICS cards to record to the Raid subsystem. When a Raid file is copied from the Raid subsystem to the local disk PI660 will only copy data from the ICS card channels that are selected into the test. This means that the raw file that results from copying an ICS Raid file will have a much different size than it does on the Raid. Further, PI660 only retrieves 2 bytes per channel from the Raid file. Since the ICS-610 board stores data as 4 bytes per channel on the Raid it is normal to expect raw file versions of ICS-610 raid files to be on the order of half or less in size of the associated Raid file. Area four lists the time and date that the Raid file was created. This can be useful in tracking when data were acquired. Area five shows the total Raid space in bytes and the Raid space available (not in use by data files stored on the Raid already). The user should ensure that there is proper Raid space prior to initiating a new recording to Raid. He can do 31

32 this by looking at area five of Figure 17, or by using the Reserve Disk Recording Space utility, or by checking the disk space available using the Test Readiness Review dialog box. The Test Readiness Review utility is discussed in a later section of this manual. Area six of figure 17 contains buttons that allow the user to de-fragment or format the Raid subsystem. Clicking the format button will force PI660 to ask a number of questions about the user s intent, and if the user verifies his intent then PI660 will carry out the intended request. Formatting the Raid will result in the loss of the data already on the Raid subsystem. It will not affect raw data files on the local disk. De-fragmenting the Raid simply compresses the file indices on the Raid so that there are no holes in the list of indices used. De-fragmenting and formatting the Raid are very quick operations. They do not take the long amount of time that it takes to de-fragment or format a Windows file system based disk drive. Area seven of figure 17 contains a button that when clicked initiates the copying of the selected Raid files to the current test directory. The files are copied into raw data files. The raw data file names are determined based on the run number of the Raid file and the test name of the Raid file. This information can be seen in the column of Figure 17 indicated by area two. The user can highlight multiple Raid files and click the button to copy them. This results in multiple raw files being generated. Area eight of figure 17 contains a button that when clicked spawns the Manage Data Files Utility. The user should use the Manage Data Files Utility after he copies data from the Raid subsystem to the local drive. Area nine of Figure 17 contains buttons that when clicked allow the user to remove files from the Raid subsystem. If the user deletes a file from the Raid then its file index is available for use. For example if the Raid contains files using file indices 1,2, and 3 and the user deletes file index 2 then the Raid Utilities dialog box will show that indices 1 and 3 are in use. If the user de-fragments the Raid by clicking the de-fragment button then the Raid Utilities dialog box will show that indices 1 and 2 are in use. Manage Data Files Figure 18. Manage Data Files Utility The Manage Data Files utility can spawn all of the data exporting dialog boxes available in PI660. It is a superb place to manage the data files from. Figure 18 shows ten unique operational areas/controls. Using the controls the user can perform all aspects of data file management and data export. Area one in Figure 18 contains a list box that shows all of the raw data files in the data file directory that the user is viewing with the Manage Data Files utility. The data file directory is indicated in area two as well as at the top of area one. 32

33 The button in area two allows the user to change the data file directory using the Browse for Folder tool written by Microsoft. Figure 19 shows the Browse for Folder tool. Figure 19. Browse for Folder Tool The Browse for Folder tool allows the user to view all directories on his PC or other PCs on the network. When the user highlights a folder (in Figure 19 the folder called atlasv is highlighted) PI660 determines the number of raw data files in the folder and displays the information about the number of raw files in the folder above the folder selection window. Area three of Figure 18 contains controls that the user can manipulate to select the run number for the next recording. The run number can be any integer number. If the user places a check mark in the Automatically Increment Run Number check box then PI660 will add one to the run number after each recording. This generally ensures that raw data files will not be overwritten by PI660. Area four of Figure 18 contains controls that allow the user to transfer raw data files to network location. This enables the user to archive or catalog raw data files without using Windows Explorer. The Network Location For File Transfer contains the Windows style naming convention for network folders. In Figure 18 the location is \\myserver\\c\c:\6000. This means computer named myserver, shared drive called C, directory c:\6000. Clicking the button containing in area four causes PI660 to spawn the Browse for Folder tool. The user uses the tool to select a network or local folder, and the Network Location For File Transfer is updated by PI660. When the user has selected a proper folder he can highlight one or more raw data files in area one of the Manage Data Files dialog box and then click the button entitled Transfer Files To Network Location. This instructs PI660 to copy the selected raw data files to the network location. Area five of Figure 18 contains a button titled Prepare For Replay. This button tells PI660 to read the data stamp of the currently selected raw data file (in area one of Figure 18) and to copy its contents into the current test settings. This is not an operation that most people use. Its use is that the data displays already defined by the user can easily be used (without change) to replay the data file. Area six of Figure 18 contains a button that spawns one of the export utility dialog boxes. The utility spawned is capable of generating Dplot, DADISP, and background plot files. The user must highlight at least one raw data file in area one of the Manage Data Files dialog box prior to clicking the button indicated by area six in Figure 18. If the user highlights more than one raw data file then the export utility dialog box will be shown once for each file that was highlighted. The export utilities are discussed in a later section in this manual. Area seven of Figure 18 contains a button that spawns one of the export utility dialog boxes. The utility spawned is capable of generating ASCII, Universal File 58, Binary EU, Binary mv, and WinPlot format files. The user does not have to highlight any raw data files in the Manage Data Files dialog box area one prior to clicking this button. The export utilities are discussed in a later section of this manual. Area eight of Figure 18 contains a button that when clicked will modify certain data stamp information in the raw data file with the current information. The scan list of the raw data file is not affected by this operation. The conversion equation information, etc. from the channels in the current test file are written to the data stamp area of the raw data file. This operation allows the user to apply different lookup tables or conversions to the data in the raw data file. Area nine of Figure 18 contains a button that when clicked will read the data stamp for the currently selected raw data file, create a text file of the data stamp, and spawn Notepad with the text file so that the user can read the data stamp 33

34 contents. If multiple raw data files are selected then the view data stamp button will spawn notepad once for each file selected. Area ten of Figure 18 contains buttons that allow the user to delete raw data files. When either of the buttons is clicked PI660 responds with a request for confirmation of the delete file operation. If the user confirms the file deletion then the raw data file(s) highlighted in area one of the Manage Data Files dialog box (Figure 18) will be permanently removed from the user s PC. Summary of Manage Raid Files & Manage Data Files Two utilities are provided that allow the user to manage and manipulate data files that are on the local disk or Raid subsystem. Data files on the Raid subsystem (from ICS digitizer components) must be copied to the local disk before PI660 can export data from the files. Raw data file names indicate the type of digitizing component that created the files. Once the user has recorded raw data files PI660 can be used to copy, export data, remove, or modify those files. There is no need for the user to use Windows Explorer for raw data file management. However, he can use Explorer if he so desires. 34

35 Export Data Files Raw data files created by PI660 can be exported to a number of different formats using two different export utilities. The two utilities are the Export Dplot Files utility and the Export ASCII Files utility. Each utility provides data exports to more than one format. The difference between the utilities is that the Export Dplot utility exports data to formats wherein there is one channel per export file created whereas the Export ASCII utility exports data to formats wherein many there is data for many channels in the export file. Export ASCII Files Utility Figure 20. ASCII Export Utility Dialog Box 12 The ASCII Export Utility Dialog Box is shown in Figure 20. It is the utility that exports data acquired and stored in a raw file to ASCII, Universal File Format 58, WinPlot, Binary EU, or Binary mv file formats. Each exported file can contain data for one or more channels from one or more raw data files. It is possible to export data in more than one format to the same file, although this is probably not a good idea. Complete descriptions of the file formats are included as an appendix to this manual. Area one in Figure 20 lists all of the raw data files in the current Data File Directory (indicated in area 6). The user can change the Data File Directory for exporting data by clicking the button titled in area 6 of the ASCII Export Utility dialog box. When the user highlights a run in area one the names of the channels in area two will be updated to show only those channels recorded into the currently selected raw file. Area two of Figure 20 contains a list control that shows all of the channels that were recorded into the raw data file. The channel names are listed and represent what the user called each channel during test definition. In Figure 20 two channels are highlighted. The ASCII Export Utility dialog box automatically selects (highlights) channels for export that the user defined as plot channels using the Select Test Channels utility. The user can highlight or remove the highlighting for channels in the area two list box by using the Windows extended select operations (click, shift click, control click). If the check box in area 4 of figure 20 contains a check mark then the list box in area two will contain names of computed channels (math engine) that can be selected for computation and export. Computed channels that have equations defined will be shown. Area three of the ASCII Export Utility dialog box (Figure 20) contains radio buttons that allow the user to choose the style of export requested. The style of export determines the file structure of the resulting exported data file. Table 7 lists the specifics about each export style. 35

36 Export Style ASCII Universal File Format 58 WinPlot Binary EU Binary mv Internal Structure Tab delimited ASCII file. Optional test information from area 7 of Figure 20 can be placed at the beginning of each export section of the file. Generally, each export section in the file contains header information from area 7 followed by a header for the channels exported to the section followed by time and data values for the channels. Data in ASCII format laid out in the fashion described for the Universal File Format 58 developed by Structural Dynamics Research Corporation (SDRC). Data values are written in Scientific Notation. Comma delimited ASCII file that conforms to the WinPlot standard. Time followed by comma followed by data and comma for each channel requested for export. There is no header information in the file Binary format file good for generating files easily read and understood by user written software. Binary format file good for generating files easily read and understood by user written software. This file format contains mv RTI data for the channels. Ie. MV values that are actually gage output mv values. No conversion to EU is performed. This file format can be generated at the same time that a Binary EU file format is exported. Table 7. File Formats Created By ASCII Export Utility Area five of the utility shown in Figure 20 contains a button that can be used to spawn a simple statistics utility. The statistics utility allows the user to determine the max and min values for channels recorded in a raw file as well as when channels achieve a certain level in the file. The statistics dialog box is the same functionally as the statistics performed by the Set Replay Position dialog box, so it is described in that section of the manual. Area seven of the export utility shown in Figure 20 contains several controls. The controls in this area affect ASCII export files only. They determine the header information to be placed into an ASCII file. Figure 21 shows the details of what the controls do Figure 21. ASCII Export Header Particulars Two types of headers are possible in an ASCII export file. They are the main header (made up of text the user enters into areas five, six, seven, and eight of Figure 21) and the channel names header. The controls in areas one, two, three, and four of Figure 21 control the placement and frequency of headers in the ASCII export file. If the user places a check mark in the checkbox in area one of Figure 21 then a main header will be placed at the beginning of the ASCII export file, and a main header will be placed at the beginning of each section appended to the 36

37 ASCII export file. Each section appended to an ASCII export file can be data from any raw data file. Choosing option 1 also means that a channel name header will appear after every main header. If the user places a check mark in the checkbox in area two of Figure 21 then appending data to an ASCII export file will insert a channel name header at the beginning of each section appended. Areas three and four contain controls that the user uses to decide how often to place a main header in the file. They are only enabled if the user places a check mark in the check box control in area one of Figure 21. Area eight of Figure 20 (ASCII Export Utility Dialog Box) contains an edit field and a button denoted. The edit field shows the fully qualified name of the file to create when the user begins the export. The user can type the name of a file (with extension) into the edit field or click the button to spawn a Select Export Output File common dialog box. He can use the common dialog box to specify the location and name of the file to create. The file does not need to exist. Further, the user can specify any file extension that he desires. Area nine of Figure 20 pertains to ASCII export files only. It contains three controls. The checkbox control allows the user to specify if the time column in the ASCII file is based on the time of day the raw file capture occurred. This can also be known as IRIG time if the user has an installed optional Bancom IRIG time code reader card in his PC. If the user places a check mark in the checkbox entitled Time Based On Hours Etc. then PI660 will use the time the raw file was acquired as the beginning time of the file. If he does not check the checkbox then PI660 will start counting time as 0.0 seconds. The two radio buttons entitled SSSSSS.ssssss and HHHH:MM:SS.ssssss allow the user to specify how the time text in the time column of the ASCII export file is formatted. If the user chooses SSSSSS.ssssss then PI660 will format the time so that it looks like the following If the user chooses HHHH:MM:SS.ssssss then PI660 will format the time as follows 0000:00: :00: Users with ICS and Pacific 6000 components will want to time align the data in the raw files for each component. Time alignment is achieved by a common signal being recorded by the 6000 component and the ICS component. PI660 allows the user to specify a digital input bit on a model 6040 digital I/O module as the 6000 system fire (time zero) signal. It also allows the user to specify an input channel on the ICS610 and ICS645 digitizer modules as a fire (time zero). Typically users route the output of a Programmable Logic Controller (PLC) to a digital input line and to an ICS input line. The configuration is shown in figure 22. The user then specifies that the ICS fire signal is asserted above approximately 3 volts. PLC Output Signal 6000 System Model 6040 Digital Input Bit ICS Card Analog Input Figure 22. Fire Switch Block Diagram Area ten of Figure 20 allows the user to select the time zero adjustment information that is added to the export file. In order to keep the export speed up, PI660 makes note of the time zero channel information during an export and adds it to a special place in each export file format. If the user chooses None as the time zero adjustment method then the time zero channel information in the export file will contain zero seconds as its value. This means that the time indicated in the file is the time to use when processing the file. This is also the case if PI660 does not find a proper fire signal in the raw data file being processed. A fire signal for a Pacific 6000 raw data file is the assertion of a digital input bit on a model 6040 digital input card. A fire signal for an ICS raw data file is a level crossing above or below a user defined analog input level on one of the ICS channels. Choosing Pacific Channel timing causes PI660 to place information about when the fire signal (digital input bit) was asserted into the exported file. The user can use this information to re-process the time information in the exported file. Choosing ICS timing causes PI660 to place information about when the fire signal (analog input line) either went above or below the user s specified level for the first time in the file into the exported file. Area eleven of Figure 20 (ASCII Export Utility Dialog Box) contains buttons that start the export process. When the user clicks the Create Selected button PI660 will create an export file with the name shown in the edit control specified by area eight of Figure 20. It will create it in a format that the user selected with the controls in area three of Figure 20, and it will export data for the channels highlighted in area two of Figure 20 from the file selected in area one of Figure 20. In Figure 20 clicking the Create Selected button would create an export file with data for channels named Pacific-DAS 1 37

38 and Pacific-DAS 12 that was recorded in the file named demorun2.raw. Clicking the Create All Runs And Channels button will cause the output file to be created with data for all channels recorded in all raw files listed in area one of Figure 20 (ASCII Export Utility Dialog Box). Area twelve of Figure 20 contains buttons that allow the user to quickly view the contents of the recently created export file. Notepad editor must reside in the Windows directory (WinNT on NT, 2000, or XP). The path to the Microsoft Excel spreadsheet (or another user specified program) can be setup by the user with the Software Settings Dialog Box. Export Dplot Files Utility Figure 23. Export Dplot Files Utility The Export Dplot Files Utility is shown in Figure 23. It is spawned from the Manage Data Files Utility dialog box. The user selects a raw data file in the Manage Data Files Utility Dialog Box (Figure 18) and clicks the Export Dplot & DaDisp button (area six of Figure 18) to make the Export Dplot Files Utility Dialog Box appear. When it appears it will have a listing of the channels recorded in the selected raw file in area one of the dialog box (Figure 23). Area two of the Export Dplot Files Utility dialog box (Figure 23) contains a listing of the channels that the user has selected for exporting. If the user has chosen T = 0 timing (area five of figure 23) to be either Pacific or ICS then the timing channel of the raw data file will be automatically selected into the area two list box. Further, Export Dplot Files Utility dialog box automatically selects (highlights) channels for export that the user defined as plot channels using the Select Test Channels utility. The user can highlight or remove the highlighting for channels in the area two list box by using the Windows extended select operations (click, shift click, control click) followed by clicking the appropriate control from area 3 of Figure 23. Area three contains controls that allow the user to add or remove channels from the list of channels to be exported (area two). To add channels the user highlights the channel names in area one and clicks the -> button. To remove channels the user highlights the channel names to remove in area two and clicks the <- button. Clicking the button containing the graphic causes all of the channels the user defined as plot channels using the Select Test Channels dialog box to be selected in area one of the Export Dplot Files Utility dialog box. 38

39 Area four of Figure 23 contains controls that allow the user to specify the output file format for the files created. This utility creates one output file per channel. The output file is named automatically for the user. The names of the files created are listed in Table 8. Export File Type Channel Type File Name Dplot Non-Computed Name Run N.dpt Dplot Computed Computed J Run N.dpt DaDisp Non-Computed Name Run N.txt DaDisp Computed Computed J Run N.txt Background Plot Non-Computed Name Run N.plt Background Plot Computed Computed J Run N.plt Where N is Run Number J is Computed Channel Number (Zero Based) Table 8. Single Channel Per File Export File Naming Conventions A Dplot file contains plotting information that can be interpreted by the Dplot program. PI660 currently ships with the freeware version of Dplot. The Dplot file type is the Unformatted Binary File Type E supported by Dplot. A DaDisp file is a text file with a header that conforms to DaDisp specifications for text input files. A Background Plot file is a text file containing tab delimited time/data pairs. It is useful as an import to the PI660 Background Plot data displays. Users with ICS and Pacific 6000 components will want to time align the data in the raw files for each component. Time alignment is achieved by a common signal being recorded by the 6000 component and the ICS component. PI660 allows the user to specify a digital input bit on a model 6040 digital I/O module as the 6000 system fire (time zero) signal. It also allows the user to specify an input channel on the ICS610 and ICS645 digitizer modules as a fire (time zero). Typically users route the output of a Programmable Logic Controller (PLC) to a digital input line and to an ICS input line. The configuration is shown in figure 22. The user then specifies that the ICS fire signal is asserted above approximately 3 volts. Area five of Figure 23 allows the user to select the time zero adjustment information that is used when creating the export file(s). A fire signal for a Pacific 6000 raw data file is the assertion of a digital input bit on a model 6040 digital input card. A fire signal for an ICS raw data file is a level crossing above or below a user defined analog input level on one of the ICS channels. Choosing Pacific Channel timing causes PI660 to adjust the time information to these export files depending on when the fire signal (digital input bit) was asserted into the exported file. Choosing ICS timing causes PI660 to adjust the time information based on when the fire signal (analog input line) either went above or below the user s specified level for the first time in the file into the exported file. Area six of Figure 23 allows the user to select that he would like to create files that export all data from the raw file for the channel, a fixed number of points from the raw file for the channel, or data that starts at a certain time in the file and ends at a certain time in the file. As a default all points are exported. Area seven of Figure 23 contains the Cancel and OK buttons. Clicking OK causes the export to begin. Clicking Cancel brings the user back to the Manage Data Files Utility box. Summary of Exporting Data Files PI660 has two primary utilities for creating exported files. Exported file formats include DaDisp text, Dplot Binary, ASCII, WinPlot, Binary mv, Binary EU, Background Plot, and Universal File Format 58 formats. The Export Dplot Utility creates export files that contain data for a single channel per file. The Export ASCII Utility creates export files that contain multiple channels per file. Further, files created by the Export ASCII utility can be appended to with data from different channels, different runs, or both. There is a time zero fire channel distinction in the data files if the user defines a time channel for the data stream. Using the time zero signal channel allows data from multiple acquisitions or multiple acquisition sources to be easily time aligned. 39

40 Test File Management All test setup information for PI660 is saved in the user s test file. A test file is either a binary proprietary file or an open architecture Microsoft Access Database file. The binary file has the extension.tst. The Access database file has the extension.mdb. The user can choose which style of test file he wishes to use. Each particular style has its advantages and disadvantages. Test files are not saved automatically. The user must tell PI660 when to save the test file. The test file does not contain data. Further, the test file does not contain screen display configuration information, computed channel information, sequencer output sequences, lookup table contents, data stream definitions, or backup data stream definitions. The test file contains information about channels, their scan rates, and their calibration information. The PI660 user can create test files that are binary in nature, read their contents, and save the test as an Access database. Similarly, the user can create test files that use the Access database structure, read their contents, and save the test as a binary test file. Test files can be stored in any location the user desires. It is recommended that the user compartmentalize his test files into subdirectories since PI660 will create many test specific information files and place them in the same directory the test file resides in. Binary Test Files Binary test files (*.tst) contain images of the internal PI660 variables that store channel setup information etc. Pacific does not currently publish the contents of the binary test files since they are continually subject to change. The binary test files are advantageous in that they are read and written quickly. Microsoft Access Test Files Microsoft Access Test Files (*.mdb) contain the information from the internal PI660 variables. The information is stored in tables inside of the Access database style test file. The Microsoft Access test files are advantageous in that they can be read and modified using Microsoft Access as well as by PI660. The Microsoft Access test files are disadvantageous in that they take longer to read and write than their binary (*.tst) counterparts. Opening A Test File The user uses the menu item File/Open to open a test file. A common dialog box appears, and it displays all files with *.mdb or *.tst extensions. If the user opens a *.mdb database test file then PI660 will read the first N channels in the database file where N is defined in the Software Settings Dialog box using the Channels In Access Database area controls. Saving A Test File The user uses the menu item File/Save to save a currently open test file. If the user has opened a test file then this operation will write the current PI660 test information to that test file. If the user has not opened a test file then PI660 does not know where to save the test information, and it will prompt the user with the File/Save As operational characteristics. If the test file is saved as an Access Database PI660 will write the first N channels into the database file where N is defined in the Software Settings Dialog box using the Channels In Access Database area controls. Saving A Test File As Using the File/Save As menu item the user can save the current test settings to a file of his choice. A common dialog box spawns for saving the test settings, and the user can specify the subdirectory and test file name. If the user does not specify the file extension for the test file (*.tst or.mdb) then PI660 will save the test file as a binary test file (.tst). If the user specifies the extension of the test file as.mdb then the file will be saved in a Microsoft Access format. If the test file is saved as an Access Database PI660 will write the first N channels into the database file where N is defined in the Software Settings Dialog box using the Channels In Access Database area controls. Saving All Files Using the File/Save All Files menu item the user can save the current test settings, the screen configuration file (*.dsw), the equation file for computed channels (*.eql), and the sequencer channel information (*.seq). PI660 will use the current test file name as the basis for naming the screen, equation, and sequencer files. For example, if the user is executing the test file named demo.tst then the file demo.dsw will be created with the current screen arrangement information, demo.eql will be created with the current math engine equations, and the file demo.seq will be created with the current sequencer setup information. 40

41 Automatically Opening The Last Test File On Startup PI660 supports an option that allows the user to automatically open the last opened test file when PI660 starts. This option can be enabled in the Automatic Actions area of the Software Settings Dialog Box. Prompting To Save File At Exit PI660 will prompt the user at exit to save the current test file if it feels that the user has made changes that are not saved. PI660 does not save the test every time the user changes a setting. It is up to the user to save the test file. PI660, however, does track changes made and will prompt the user. Summary of Test File Management PI660 supports Access database and proprietary binary test files. The user can use both styles at will. The can save his channel setup, calibration information, scan rates, etc in a test file. Users are encouraged to create new test files whenever the test configuration changes considerably. Users are further encouraged to save early and save often. 41

42 Data Display Creation The Windows menu selection allows the user to define the displays he will use during data acquisition. The software allows the user to create as many different displays as he would like. The user can also save the display set up to a file for future use. The display engine is a multiple document interface. The multiple document interface allows the user to create many of the same type of display. For instance, the user can ask the software to create 10 oscilloscope Windows. Each of the Windows is managed by the same piece of code in the software, but each of the Windows has different parameters. The PI660 software provides tabular, oscilloscope, spectrum analyzer, bar graph, strip chart, bitmap picture, and XY charts. Each of the display types has a different function. The user may mix-and-match displays on the screen anytime. All the displays are sizable by the user. The software provides commands that Cascade and tile the Windows for the user. The Windows/new menu selection provides a submenu that allows the user to create a new window display. By clicking on the display type desired the user instructs the software to create a new display. There are selections in the menu for each of the display types. At the top of the submenu is the multiple selection. The multiple selection allows the user to create many other particular display types at once. When the user create small full displays the displays will contain different channels. The software will select the channels in the scan list starting at the lowest channel number in continuing to the highest channel number. Each display window has the properties dialog box associated with it. The properties dialog box will be shown when the user clicks the right mouse button over the display. Each of the properties dialog boxes differ depending on the window type and channel parameters selected for display in the window. The properties dialog boxes allow the user to select the channels for the display. The properties dialog boxes also allow the user to define display specific parameters. The display update rate is based on many parameters. Each display has a priority associated with it. The priority for a particular display can be changed inside of the displays properties dialog box. Displays are updated by the software as quickly as the software can perform updates. The display updates occur after the software has received a buffer of new data from the 6000 system. The software receives offers of data from the 6000 system approximately every one hundred and fifty milliseconds. When the software receives a new buffer of data the display thread begins processing data and the displays begin displaying the data. The display thread attempts to process all of the data for all of the channels in the buffer. At higher rates and data acquisition the display threatened will not be able to process every sample of data from every channel. There is a setting in the eight locations and capabilities menu selection of the options menu that allows the user to tell software how many samples to skip while processing a buffer. This setting will lower the processor utilization on the PC. It will also provide for smoother updates of the displays. The user is encouraged to investigate this setting in determined the best setting for his PC. Tabular Display The figure above shows a typical tabular display. Each tabular display has the ability to display data from up to 20 channels. Again, the user can ask the software to create many tabular displays. The tabular displays show the channel name, raw channel A to D counts, and engineering unit value. The raw counts can be displayed in decimal, hexadecimal, octal, or binary form. The engineering unit value can be displayed with a varying number of digits after the decimal point. The font used for each display can be changed by using the Windows/font menu selection. 42

43 The figure above shows the properties dialog box for the tabular type display. It contains two list boxes. The left most list box shows the channels that are in the scan list. And the right must list box shows the channels which are in the display. The radix section of the properties dialog box allows the user to select the format that the display will use for the raw data. The scale to fit section of the properties dialog box allows the user to tell the software whether or not to scale the text in the display. The display title area of the properties dialog box allows the user to give the display a title. The title will be displayed in the window bar at the top of the display. The precision area allows the user to specify the number of digits after the decimal point for the engineering unit value. The precision can be chosen to die from zero to 10. The priority specifies the speed that the display will update. The priority can be selected in the range of 1 to 100. A priority of 1 means fastest update. The colors area of the properties dialog box allows the user to specify the good, warning, and alarm colors for all of the channels in the display. The color settings are channel based. This means that if the color is changed for a channel on a display then all other displays showing that channel will be affected. To add new channels to the display the user simply highlights channels can be available list box and clicks on the add button. Likewise, the user removes channels from the display by highlighting channels in the selected list box and then by clicking remove. Alternatively, the user can add or remove channels by double-clicking on the appropriate list box. The tabular display will also allow the user to select computed channels for display. Computed channels are generated by the math engine. Further, the tabular display will allow the user to show the status of the system trigger, system mark bit, system alarm, system warning, and system general alarm. These last display elements can be found at the bottom of the available channels list box. Oscilloscope Display 43

44 The figure above shows an oscilloscope window. The oscilloscope window shows data from a single channel. The user may simultaneously display many oscilloscope Windows. The oscilloscope window is different from any other window types in that it contains 512 samples of time continuous data. This type of display is a dynamic display. If the user is sampling at very low speeds the oscilloscope window may take a long time to update. The oscilloscope window is best for channels with sample rates above 1000 samples per second. When the sample rate is high the oscilloscope window provides a very good representation of dynamic signals. The oscilloscope window contains a large black region in the center of the display. The black region is separated into a hundred different squares. The squares are made by the intersection of the grid lines. Thus, there are 10 grids along the X axis and 10 grids along the Y axis. The oscilloscope display shows the data in engineering units. The maximum and minimum engineering units values are indicated above and below the black region on the left side. Along the top of the black region in the center is a text field indicating the engineering units per grid. Along the bottom of the black region in the center is a value that indicates either RMS value or mean value of the points currently on the display. In the lower right hand side of the display the amount of time data that the display contains is indicated. The properties dialog box for the oscilloscope window is shown above. A contains a combo box for selecting the channel to display on the oscilloscope display. It also contains a display style region. The oscilloscope display can become a spectrum analyzer window or a windowed spectrum analyzer. Each oscilloscope display has a title, and the software will create a gene ric title for the display when the user selects a new channel. Both the X and Y scales can be zoomed in. Zooming in his performed by selecting a percentage in they scale edit box, or by selecting a number of points to skip in the X decimation area. The user can also choose between RMS and mean value for the text displayed at the bottom of the oscilloscope window. Bar Chart Display 44

45 The bar chart window allows the user to create displays with vertical bars that are user scalable. Up to 96 different bars can be placed on each display. Each bar on the display is user definable and user scalable. A bar on the bar graph consists of a channel name, maximum value, minimum value, and alarm bar, and a data bar. The data bar changes color and height depending on the engineering unit value for the channel. The alarm bar is placed to the left of the data bar, and it indicates the relative position of the alarms for the channel. The maximum and minimum values are selected by the user in the bar chart properties dialog box. If the maximum and minimum values are lower than the channel alarms the alarm bar will not display different colors. If the user left mouse clicks a bar on the bar chart window the software will display a message box that indicates the current value for that channel. The current value for the channel will only be valid if the software is scanning data from the 6000 system. The figure above shows the bar graph properties window. Like all of the other properties dialog boxes it contains an area to give the display a title. In the upper left-hand side of the dialog box there is the available channels list box. To the right of that list box is the selected channels list box. Channels are added and removed from the display in the same fashion as they are added and removed from the tabular window. Please refer to the text concerning the tabular window properties dialog box. In the upper right hand corner of the bar graph dialog box there is a range area. Inside of the range area the user can enter the maximum and minimum values for the data bar for individual channels. In order to an air the maximum and minimum values the user must first select a channel in the selected channels list box. When the user selects the channel the current range for the channel data bar is displayed in the from and to edit boxes. The priority entry for this display functions in the same fashion that the priority entry for the tabular display does. Also, the good, warning, and alarm color of buttons function identically to those found on the tabular display. Adding and removing channels to the bar graph display is performed as it is for the tabular display also. Spectrum Analyzer Display 45

46 The spectrum analyzer display is a special version of the oscilloscope display. It contains information from a single channel. The information in the display comes from time continuous data. The time continuous data stream consists of 512 points. The software performs a 512 point FFT on the time continuous data. The result of the FFT is a 256-point magnitude array in engineering units. The controls for this display type are identical to the controls for the oscilloscope window. The spectrum analyzer window will display the data using a red trace. The oscilloscope displays the data using a green trace. XY Chart Display The figure above shows the XY Chart display window. The XY Chart display window plots up to 9 different channels on the Y axis vs. a single channel on the X axis. Each channel on the Y axis will be displayed in a different color. This display type does not show alarms and warnings via color changes. The first Y axis channel is the primary Y axis channel. It determines the maximum and minimum Y axis values. The data for the XY Chart is displayed in engineering units. The data can be displayed as points or points connected by lines. The display has the capability to maintain history data for the channels. Each Y axis channel has a 512 data point array associated with it. As data becomes available for the XY Chart the software begins filling the arrays. When the arrays fill the software decimates the contents of the arrays. In doing so the software retains half of the data in the array. This means that the software will maintain data values for each Y axis channel that span the duration that the display has been used. The user can choose to clear the history arrays via a command in the XY Chart properties dialog box. The figure above shows the XY Chart properties dialog box. The parameter selection area of the dialog box allows the user to select the primary Y axis and primary X axis channels. These two channels are used to determine the scaling of the Y axis in the X axis. Data values that fall outside of the scale limits will be clipped by the software. The user can also scale the X axis and the Y axis to zoom in or to zoom out. Additional Y axis channels may be added by increment gain the total Y axis channels combination box in the drawing style area of the XY Chart properties dialog box. In the drawing style area the user can also select connection of points and the rate at which the software saves data values to the history buffers. A larger entry in the saved points to history buffer every blank points edit box slows down the generation of data to the history buffers. The history buffers are used to redraw the traces for each Y axis channel when the XY Chart is 46

47 resized. The XY Chart also has a display title. The title functions the same as the titles for the other display types. Only the channels available in the scan list will be shown in the channel selection combination boxes. Strip Chart Display The figure above shows the strip chart display. The strip chart display can contain up to 10 different traces. Like all other displays the user can create many strip chart displays. The left-hand side of the strip chart display is the data display region. The data display region is meant to act like the paper in a mechanical strip chart. New points are added to the data display region on the right hand side. At the right hand side of the data display region is the pen carriage. Each sub region within the data display region can be scaled on the Y axis. Also, the user can have time lines placed onto the scrolling data display region at user-defined intervals. The right hand side of the strip chart display contains the channel names, counts, and engineering units values for the last data placed for the channel. The strip chart display properties dialog boxes shown above. It functions in much the same way as the properties dialog boxes described above. There are two list boxes in the upper left-hand corner of the dialog box. The left most list box shows the available channels, and a right must list box shows the channels that are part of the display. The scale region of the dialog box functions in the same fashion that the range region of the bar graph properties dialog box does. By selecting a channel in the selected list box the maximum Y axis scale and minimum Y axis scale for that channel will be displayed in the scale area. The user may enter new values for the maximum Y axis and minimum Y axis scales for the selected channel. The radix area indicates to software how the raw data should be displayed. Valid selections are decimal, hexadecimal, octal, and binary. The precision, priority, scale to fit, and options areas function identically to those found in the tabular properties dialog box. The time lines area contains a check box called display and an edit box. The 47

48 display check box is used to indicate whether or not user desires to have time lines displayed. If the user places a check in the check box the software will add time lines to the display. The time lines will be added approximately every N seconds where N is the value user placed into the time lines edit box. 48

49 Bitmap Picture Display Window The figure above shows a bitmap picture display window. The user may create many picture windows. The picture window displays a bitmap image with color dots on the image. The color dots on the image represents the values of different channels. For example, if the user is testing an aircraft he may have many sensors on the aircraft engine. If the user has a bitmap picture of the aircraft he can use the picture display window to define the location of the transducers on the wing. As data are being acquired the software will indicate whether or not the data for each of the transducers is in the alarm, warning, or good data range. The transducer data are displayed as colored circles on the engine. The user may click on the colored circles to retrieve the current data value for individual transducers. This display is useful in that the user can visualize the test article and the data being acquired. Any valid bitmap image can be imported into a picture display window. The user can also use programs such as paint to create bitmaps that will be displayed in the picture display window. If the user left mouse clicks over a sensor the PI660 software will display a message box that indicates the current value of the measurement for the sensor. The figure above shows the picture window properties dialog box. It contains the available channel list box and the selected channels list box. These function in the same fashion as the list boxes in the other display properties dialog boxes. The same can be said for the precision, priority, display title, and colors buttons. The bitmap file region of the dialog box contains the name of the bitmap file being displayed in a button that spawns the open file that dialog box. With the open file dialog box the user can search the disk and specify a bitmap file for the picture window to display. Once the user has specify a bitmap file for the picture window display the bitmap will be displayed in the lower right-hand region of the picture window properties dialog box. The bitmap is displayed here so that the user can define locations of the transducers. To define the location of the transducer highlight the channel in the selected channels list box and then a click the move button in the hot spot properties area of the dialog box. When the user does this the mouse will be captured in the bitmap display area of the picture window properties dialog box. The mouse will remain captured until the user clicks the left mouse button to define the position of the selected transducer. When the user deposits the transducer at its location the software will show the location of the transducer as a circle. The user can also define the size of the spot for each 49

50 transducer. The size of the transducer spot is defined by selecting the transducer in the selected channels list box and then entering the size (in pixels) in the size edit box inside of the hot spot properties region. When the user exits the picture window properties dialog box the new bitmap will be displayed in the picture window. If the user sizes the picture window the bitmap will be stretched to its new size. Quick Plot Window The quick plot window is shown above. It is not a dynamic data display. The quick plot window is used to display data acquired for individual channel. The user can request multiple quick plots from the software. The quick plot will display the channel data for the selected channel for the current data run. For more about data runs see the files section of this manual. The data in a quick plot can be auto scaled, digitally filtered, and annotated with alarm in warning information. The digital filtering provides low pass, high pass, band stop, and band pass filtering. The digital filtering is performed in the frequency domain, and it is performed twice with data reversal to remove time shifts. The quick plot window provides a fast mechanism for reviewing channel data acquired. The user is encouraged to perform posttest analysis with the included D-plot analysis package. Alternatively, the user is encouraged to utilize the export functions of the software and to analyze data more thoroughly with a third party package. In the above example the user has acquired a sine wave. In the following figure the user has instructed PI660 to digitally low pass filter the sine wave. The result shows some ringing at the ends as expected, but the result is not time shifted. The software performs the filtering twice with end to end data reversal to remove time shift imparted by the FFT digital filter mechanism. The data are reversed again after the two step filtering so that the user views the data in the proper left to right order. 50

51 The quick plot window properties dialog box is shown above. The user selects the channel to plot, the digital filtering (if any), and the display style (spectrum or time history). The user can also specify auto scaling and data checking. Auto scaling will provide a display in which the Y Axis is scaled to the max and min values the signal achieved during the recording. The Band pass and band stop filters require an entry in the second (from the top) cutoff frequency edit box. The first cutoff frequency edit box is the low end frequency, and the second cutoff frequency edit box is the high end frequency. Open Screen, Save Screen, Save Screen As The PI660 software has the ability to save screen display setup information to files. The files have the.dsw extension. The user specifies the prefix of the screen file name and the subdirectory to place the screen file into. The Windows/Open Screen menu selection allows the user to open a screen file. Likewise, the Windows/Save Screen and Windows/Save Screen As menu selections allow the user to save a screen setup. The screen setup files are text files that contain all of the window properties that are currently defined. One of the properties for each window is the channels contained in the display. The channels in a display must be in the scan list for the display to be valid. If a screen file is opened that contains displays that reference only channels not in the scan list then the software will remove the displays from the screen. For example consider a display file contains two tabular displays and the first tabular display contains references to channels 0-10 and the second tabular display contains references to channels If the scan list contains channels 0-9 then the software will not show the second tabular display, and the software will remove channel 10 from the first tabular display. Screen files can be opened during preview and record. When a new screen file is opened all of the current displays will be removed from the viewing area first. Cascade, Tile, & Arrange Icons, Close All The Windows/Cascade, Windows/Tile, and Windows/Arrange Icons menu selections help the user manage the displays he is viewing. The commands do the operations that are expected in conjunction with the Windows Operating System interface. The Windows/Close All menu selection closes all of the display windows. Properties, Fonts, Print The software has the ability to change the fonts for each display being shown. To change the font for a display click (left mouse) on the display to give it focus and then select the Windows/Fonts menu selection. Then pick the desired font. You may have to resize the display for the new font to take affect. Each display can be printed also. The Windows/Print opens the print common dialog box and allows the user to send the image of the display in focus to the printer. The Windows/Properties command performs the same function as a right mouse click over a display window. It opens the properties dialog box for the given display window. The properties dialog boxes are discussed above for each display type. 51

52 Calibration Of Channels The input channels of the 6000 system are calibrated at the factory, and data sheets for each channel are provided. Factory calibration ensures that the channel modules operate in accordance to the tolerances specified in the data sheets. The 6000 system can perform an automatic zero operation on the amplification stages of the channel when the gain or filter is changed. The user must activate the automatic zero functionality for each channel using the channel parameters dialog box to take advantage of this feature. Auto zero ensures that the offset of the amplifier stages remains at zero across temperature. Calibration with PI660 augments factory calibrations. It allows the user to formulate equations that convert voltage measured to voltage traceable to a standard, and that convert voltage traceable to engineering units. It should be noted that it is not entirely necessary to use PI660 for formulating an equation for voltage measured to voltage traceable to a standard since the factory calibrations of the channels provide this feature within Pacific Instruments published specifications for the channel modules. However, if the software is used to formulate voltage measured to voltage traceable equations the user will see results that are better than Pacific Instruments published specifications (in most cases). Table X lists the calibration tools that can be used and their affects on measurements. Calibration Tool Purpose Voltage Calibration Converts voltage measured to voltage traceable using an EDC model 522 programmable voltage calibration source. Note, this is done at the factory, and performing this in the field simply enhances the measurement quality and verifies proper signal conditioning accuracy. Engineering Unit (EU) Calibration Converts voltage traceable to engineering units. If the measurement is only required in mv then this process is not required. If the user wants to enter the conversion equation manually then this process is not required. If the user is using a look up table then this process is not required. EU calibration can be performed in DC and AC modes. Strain Gage Calculator Accepts user s information about gage factor, gage resistance, line resistance, and full scale expected value to arrive at a best (highest) gain for the channel(s). Also calculates an EU conversion equation for each strain gage assuming a theoretical zero EU equation offset Tare Calibration Allows the user to select one or more measurement channels and to equate the EU value measured now to a certain EU level. The Tare Calibration modifies the EU equation offset coefficient. EU Calibration Coefficient Calculator Allows the user to enter two points from a transducer data sheet so that PI660 can calculate a straight line EU conversion equation from the transducer data sheet data. Using this option is analogous to entering the EU conversion equation coefficients manually. Lookup Tables Allows the user to enter up to 50 different lookup tables that contain from 2 to 30 point pairs of mv inputs and their equivalent EU values. PI660 calculates slopes and offsets for the point pairs in a piecewise linear fashion. Using this technique for a channel alleviates the need for an EU conversion equation. Automatic Zero Instructs the 6000 system channels to remove amplifier drift using on board DACs that suppress instrumentation amplifier zero drift. Performing this operation or downloading a channel s settings will cause an automatic zero to occur. PI660 then reads the residual and uses it as part of the Voltage Calibration offset coefficient. Zero Plug Calibration Instructs the 6000 system card selected to perform an automatic zero (amplifier drift removal), read the residual zero value at the input to the instrumentation amplifier, read the zero input from the card edge connector (user supplied zero plug), store the difference between the card edge zero and the instrumentation amplifier zero input in EEPROM, and update the Voltage Calibration offset coefficient with the sum of the two offsets. Bridge Balance Instructs the 6000 system channel(s) selected to perform a bridge balance using the on board automatic balance DACs. Automatic bridge balance injects voltage into the bridge output (+ or signal) that eliminates the bridge s current offset voltage. Bridge Balance does not inherently affect coefficients of the conversion equations, but should be performed prior to EU calibration. Table X. Calibration Tools & Their Meanings Not all calibration tools need to be used to make measurements. The calibration tools that are used will vary depending on user requirements and gage type. Table XX shows some typical transducer types and possible scenarios for calibration. Please note that the PI660 software is very flexible and allows the user to define calibrations and calibration techniques with complete openness. It is the user s decision how to perform calibrations, what calibrations to perform, and the frequency of performing calibrations. 52

53 Thermocouple RTD Bridge Strain Gage Accelerometer Voltage DC LVDT ICP/IES Transducer Type Calibrations Tools That Make Sense Voltage Calibration, Automatic Zero, and Internal Lookup Tables From NIST, Zero Plug Calibration Voltage Calibration, Automatic Zero, DC EU Calibration, Tare Calibration, Lookup Tables, EU Calibration Coefficient Converter, Zero Plug Calibration Voltage Calibration, Automatic Zero, DC EU Calibration, Tare Calibration, Lookup Tables, EU Calibration Coefficient Converter, Zero Plug Calibration, Bridge Balance Voltage Calibration, Automatic Zero, DC EU Calibration, Tare Calibration, Lookup Tables, EU Calibration Coefficient Converter, Zero Plug Calibration, Bridge Balance, Strain Gage Calculator Voltage Calibration, Automatic Zero, DC EU Calibration, AC EU Calibration, Tare Calibration, Lookup Tables, EU Calibration Coefficient Converter, Zero Plug Calibration, Bridge Balance Voltage Calibration, Automatic Zero, Zero Plug Calibration Voltage Calibration, Automatic Zero, DC EU Calibration, Tare Calibration, Lookup Tables, EU Calibration Coefficient Converter, Zero Plug Calibration Voltage Calibration, Automatic Zero, DC EU Calibration, AC EU Calibration, Lookup Tables, Zero Plug Calibration Table XX. Some Transducer Types & Their Possible Calibration Tools Calibration Basics The calibration concept is to take some type of measured signal, convert it properly to a voltage representation, and to then convert that voltage representation to an Engineering Unit (EU) quantity. PI660 uses two equations to perform the task. Table Y shows the calibration equations used by PI660, and Table Z shows the meanings of the nomenclature used in Table Y. PI660 acquires raw data from the channel A to D converters. The raw data is known as A to D counts. Generally speaking the range of counts available is to equating to mv and mv respectively for the voltage presented to the A to D converter. This voltage presented to the A to D converter is known as mvrto where RTO means referenced to output of the instrumentation amplifier. mvrto is simply the mvrti (where RTI means referenced to input of the instrumentation amplifier) multiplied by the gain for the channel. For example, a gage outputting 1 mv into a channel using gain 5000 would be said to read 1 mv RTI and 5000 mv RTO. PI660 performs all conversions using mvrti as the basis. This means that the user does not need to factor gain into his calculations. PI660 takes care of the gain for the user. For instance, using the same example, the A to D converter would read counts since the input signal (1 mv) multiplied by a gain of 5000 yields 5000 mv at the input to the A to D converter. Since the A to D converter has a full scale input range of +/ mv the A to D converter would digitize the value as counts. PI660 then uses the counts measurement, the channel gain,knowledge that the A to D converter is a +/ mv device, and knowledge that the A to D converter is a +/ count device (16 bit converter) to calculate that the input to the amplifier was really 1 mv. It uses this 1 mvrti as the basis of all calculations performed by the equations listed in table Y. Equation Purpose Equation Number mv T = (mv M * Slope V ) Offset D - Offset AZ Voltage Calibration Equation 1 EU = Offset EU +(mv T * Slope EU ) + (mv 2 T * Squared EU ) + (mv 3 T * Cubed EU ) EU Conversion Equation 2 Table Y. PI660 Data Conversion Equations Quantity mv T EU Slope V mv M Offset D Offset AZ Offset EU Slope EU Meaning mv Traceable To Department Of Standards Engineering Units Value Slope obtained by performing Voltage Calibration Millivolts measured by PI660 using gain & A/D range Difference in offset in mv from shorting plug calibration and autozero reading (Offset AZ ) Offset in mv obtained from reading channel in autozero mode User s offset for EU equation converting mv to EU User s slope for EU equation converting mv to EU 53

54 Squared EU Cubed EU mv N T User s squared coefficient for EU equation User s cubed coefficient for EU equation Traceable mv raised to Nth power Table Z. Nomenclature for Table Y Equation 1 converts voltage measured to voltage traceable, and its coefficients are generally arrived at automatically using PI660 and a programmable EDC Model 522 Voltage Calibrator. Equation 2 converts either voltage measured or voltage traceable to Engineering Units (EU). Each channel in the 6000 system will have its own set of equations. Note, voltage measured will exactly equal voltage traceable if the Slope V coefficient is 1.0 and the Offset D = Offset AZ = 0.0. Input Circuit Discussion Understanding the calibration conversion equations and their usage requires a general understanding of the input circuit of a signal conditioning amplifier. The following diagram of a generic input circuit can be referred to when discussing the calibration conversion equations. + Input Protection (R1) - Input Protection (R2) i1 i2 X Filter Or Wideband Auto Zero DACs A to D Converter Auto Zero Short To Ground Voltage Cal Circuitry (R3 & R4) EDC 522 Traceable Supply Figure Input Circuit Basics The figure shows a block diagram of the input circuitry for a typical Pacific Instruments model 6000 analog input channel. It shows the voltage traceable supply (the EDC 522), the voltage calibration circuitry, the automatic zero DACs, the input protection, the input selection switch, the amplifier (X), the filter, the automatic zero input, and the A to D converter. It also points out quantities i1, i2, R1, R2, R3, and R4. These quantities are the source currents (i1 and i2) from the amplifier, the input protection resistances (R1 and R2), and the voltage calibration range selection resistances (R3 and R4). To fully understand the level of commitment Pacific Instruments has to its customers it is important for the customer to understand the basic characteristics of instrumentation amplifiers, and, in particular, how Pacific Instruments compensates for the characteristics (parasitics). Any instrumentation amplifier manufactured will generate source currents. Source currents are the currents that flow out of the inputs of the amplifier. In the figure above the source currents are denoted as i1 and i2. Contrary to engineering text on amplifier use i1 and i2 are not zero amps. They are very small, and in most circuits they can be dismissed without further investigation. However, in a signal conditioning application the source currents must be either removed (which requires expensive additional circuitry and trimming) or compensated for. Please note, i1 i

55 The source currents flow through the resistances (R1 & R2) in the amplifier input protection circuits when the input switch is in the transducer input mode, and they flow through the resistances (R3 & R4) in the voltage calibration circuit when the input switch is in the voltage calibration input mode. Please note, R1 R2 R3 R4 0. As the source currents (i1 & i2) flow through the input resistances (R1 & R2) voltages are developed. We denote those voltages as V1 and V2 where V1 = i1 * R1 V2 = i2 * R2 Since the source currents are small ( 2nA or so) and the resistances are small the voltages introduced are small. However, the voltage (V1) imparted on the + input lead can have a different polarity than the voltage (V2) imparted on the input lead. In this case the effects are additive. Typical differential voltages between the input leads can be as high as 2 microvolts. Using a high gain (ie. 5000) the affects of the source currents working against the input protection resistances comprise a larger percent error than they do at low gains since the high gain allows the A to D converter to quantify the errors. A similar situation exists for the voltage calibration path where the source currents flow through resistances R3 and R4 to develop voltages V3 and V4. It is clear from the previous discussion that it is highly likely that V3 V4 V1 V2. Determining The Offset Coefficient Of The Voltage Calibration Equation (Equation 1) PI660 uses automatic compensation of the source current errors. It also allows the user to tune the compensation. The following figure shows the input circuit from above with some additional nomenclature. Card Edge Shorting Plug + Input Protection (R1) - Input Protection (R2) i1 i2 X Filter Or Wideband Auto Zero DACs A to D Converter Offset D Offset AZ Auto Zero Short To Ground Voltage Cal Circuitry (R3 & R4) EDC 522 Traceable Supply True Ground (Zero) Figure Input Circuit Showing Voltage Calibration Offset Quantities The figure introduces the concepts of a card-edge shorting plug, the terms Offset D, Offset AZ, and True Ground (Zero). The equation for converting the input millivolts measured (differential voltage between + input and input) to voltage traceable takes the following form mv T = (mv M * Slope V ) Offset D - Offset AZ 55

56 Where mv T = mv Traceable To Department Of Standards Slope V = Slope obtained by performing Voltage Calibration. mv M = Millivolts measured by PI660 using gain & A/D range Offset D = Difference in offset in mv from shorting plug calibration and autozero reading (Offset AZ ) Offset AZ = Offset in mv obtained from reading channel in autozero mode. The offset portion of the voltage conversion equation has two terms. They are Offset D and Offset AZ. The terms are shown in the figure above. The Pacific Instruments Automatic Zero circuit uses DACs that inject voltage into the instrumentation amplifier to suppress offset drift of the instrumentation amplifier. Automatic zero is performed on a channel when the user downloads gain or filter settings to the channel or when the user selectively performs an automatic zero using a software command. When the automatic zero is performed the firmware on the amplifier card switches the amplifier input to the auto zero short to ground mode. A figure of the circuit in automatic zero mode is shown below. + Input Protection (R1) Note Switch Positions - Input Protection (R2) i1 i2 X Filter Or Wideband Auto Zero DACs A to D Converter Auto Zero Short To Ground Voltage Cal Circuitry (R3 & R4) EDC 522 Traceable Supply Figure Input Circuit With Automatic Zero As Input The input zero from the Auto Zero Short To Ground flows into the instrumentation amplifier and through the filter circuit and into the A to D converter. The firmware performs a successive approximation voltage injection routine wherein the Auto Zero DAC outputs are varied and the A to D counts are read in a looping fashion. When the firmware reads a zero value from the A to D converter that is within specifications for the automatic zero circuit (as denoted in the Pacific Instruments specifications for the amplifier) it stops looping. The result is a zero in from the automatic zero short to ground that gives a zero out (within specifications) at the A to D converter. The automatic zero is said to be within specifications when the automatic zero algorithm completes properly. This, however, does not mean that the output of the amplifier is absolutely zero (on average). The DACs used in the automatic zero circuit are digital in nature and thus can inject a finite number of different voltages. Since the circuit is not continuous in nature there will be a small residual (denoted Offset AZ ) that the software can account for. After the firmware performs an automatic zero the amplifier input is returned to normal transducer input mode by the firmware. The software then places the channel back into the automatic zero input mode and scans 1000 points of data from the channel s A to D converter. The mean value of the 1000 points is stored in the software as the quantity Offset AZ to be used in the voltage calibration conversion equation. The Offset AZ indicates the offset of the amplifier circuit in automatic zero input mode, but due to the source currents (i1 & i2) and the input protection resistances (R1 and R2) the term Offset AZ does not indicate exactly what the total offset is through the normal input path (transducer input). 56

57 Improving The Voltage Calibration Offset Coefficient Using Zero Plug Calibration The difference between the normal input path zero and the automatic zero input path can be characterized by the PI660 software. This improves measurement accuracy and has been shown to be quite useful in obtaining accuracies well beyond specified accuracies for the channel input modules. The key to resolving the difference between the two path offsets is in a process known as the zero plug calibration. The user can perform a Zero plug calibration if he desires the best accuracy (better than specifications) from his channels. It is normally performed one time in the life of the channel. The following figure shows the circuit in the zero plug calibration mode. Shorting Plug + Input Protection (R1) - Input Protection (R2) i1 i2 X Note Switch Positions Filter Or Wideband Auto Zero DACs A to D Converter Auto Zero Short To Ground Voltage Cal Circuitry (R3 & R4) EDC 522 Traceable Supply Figure. Input Circuit With Shorting Plug As Input The user affixes a card edge connector that connects the + and inputs of each channel on the card to each other (not channel to channel though). He then uses the software to perform the zero plug compensation procedure. When the software performs the zero plug compensation it is merely characterizing the difference between the transducer input path shorted by a zero plug and the automatic zero input path. In performing the zero plug compensation the software first sets the channel to its highest gain (5000 in most cases) and this in turn causes the channel firmware to perform an automatic zero. The software then places the channel into the automatic zero input mode and reads the result of the firmware s latest automatic zero operation. After that, the software returns the channel to the normal input mode and reads the zero plug average. The difference between the normal input mode zero plug reading and the automatic zero offset (Offset AZ ) is then calculated. This quantity is known as Offset D where the D stands for Delta. Offset D remains essentially constant across all gains and temperature ranges of the amplification circuit. The quantity Offset D is stored in the channel s non-volatile EEPROM memory. If the user has not performed a zero plug compensation the quantity Offset D is 0.0 and thus has no affect. When the software collects the quantity Offset AZ after an automatic zero operation it also collects the quantity Offset D from the channel. Collection of the quantities is performed when the channel gain or filter is changed or when the channel is autozeroed by the user. The zero plug calibration can either be: Bypassed (In which case the Pacific Instruments specifications apply for channel measurement accuracy). Performed at the card edge connector Performed at the end of the user s input cables (In which case all Extraneous signal anomalies are resolved). 57

58 Voltage Calibration Slope Coefficient Determination Slope V and mv M are the other parts of the voltage calibration conversion equation. The quantity mv M is millivolts measured, and it is in the millivolt signal referenced to input of the channel (ie. the A to D counts back calculated through the gain so that the input mv level is known). The equation for mv M. is mv M = (((A to D Counts) / 32768) * ) / Gain The quantity Slope V is the slope of the amplifier circuit, and it is arrived at using the voltage calibration input path and the output of the EDC precision voltage calibrator. If the user performs voltage calibration then the quantity Slope V will most likely not be It will, however, be within the specifications for voltage linearity for the Pacific Instruments channel modules. When the user performs a voltage calibration the PI660 software determines the EDC output levels necessary for the gain of each channel being calibrated. It selects channels to calibrate by gain used, and calibrates the channels in parallel. The EDC levels selected are +/-80%, +/-60%, +/-40%, +/-20% and 0% of the amplifier full scale input range. The software collects 512 points of data for each channel for each input level and then averages each collection of points for each input level. A least squares fit is performed on the data, and a slope and and offset are determined. The points are checked for overrange, noise, flat line response, and single step non-linearities. The slope is the only part of the equation that is kept from the voltage calibration. This is since (please see the discussion above) the voltage calibration path offset is different from the input path offset due to source currents (i1 and i2) and resistances (R1, R2, R3, and R4). The slopes of the paths are the same, however. The user can choose to enter an engineering unit conversion equation directly into the software for each channel, or he can perform engineering unit calibrations that calculate the equations for him. The software provides several types of engineering unit calibration techniques. It allows multi-step static level calibrations, AC calibrations, and offset calibrations. The multi-step static level calibrations are used when the gage(s) to be calibrated will have known static levels applied to them during the calibration steps. The AC calibrations are performed as one step calibrations where the input is sinusoidal with a known amplitude. The offset calibrations are performed as one step calibrations where the slope of the EU conversion equation is known and where the user desires the one calibration step to denote the initial EU value to tare out of the measurement (ie. the zero position when the gage output is non-zero). Performing Voltage Calibration Slope Coefficient Determination Voltage calibrations are performed on the analog input channels of the 6000 system and on the ICS-610 cards that can be operated with the system. The PI660 software supports the concept of a main DAS and a parallel backup DAS. When the software performs voltage calibrations on the main DAS the backup DAS is instructed to perform voltage calibrations automatically in parallel. Voltage calibration is the process whereby amplifiers are calibrated to a known traceable standard. The 6000 DAS uses the EDC Model 522 programmable precision voltage source as the basis for voltage calibrations. The PI660 software controls this source during the process of voltage calibrations. When the software performs voltage calibrations it programs the EDC voltage source to levels that represent +/- 80%, +/-60%, +/-40%, +/-20%, and zero percent of full scale for each channel. The voltage outputs of the EDC flow through the voltage calibration bus of the 6000 system and into the selected channels. The values are acquired (512 samples per step) and analyzed. The analysis of the values mimics the analysis performed during EU calibration. When all of the values have been acquired the software performs a least squares fit of the data and generates the resulting slope and offset for each channel. The slope and offset for each channel are known as voltage slope and voltage offset respectively. They form the equation of the line that converts mv measured to mv traceable. The mv measured values acquired by the software are passed through the voltage calibration equation to produce mv traceable quantities. The mv traceable quantities are passed through the EU conversion equation (or Thermocouple lookup tables) to produce EU values. To perform Voltage calibrations the user of the 6000 system must have an EDC 522 programmable precision voltage source connected to the system communication bus (GPIB) and to the Voltage Calibration bus on the 6000 system, or a non-programmable precision voltage source connected to the Voltage Calibration bus on the 6000 system. Note, the Pacific Instruments channels are calibrated using the EDC 522 at the factory before they are shipped to the customer. All gains and offsets are verified to be within specifications, and all channels are aligned. The advantage of using the EDC 522 voltage calibrator in the user s facility is that each channel (gain and filter combination) can be software compensated on a daily basis, and the software compensation can yield better overall results in cases where absolute traceable voltage measurements are a must. For example, if the root sum squared (RSS) of the error sources possible for a channel is equal to some quantity X, then performing the voltage calibration on the channel in the field has the ability to make the resulting error from the channel X/N where n can be as little as one or as much as about 5. Voltage calibrations are only suggested if Transducer data sheets are being used as a source of calibration information (ie. traceable voltages equivalent to EU from the gage) and 58

59 and the user wants better results than the RSS specified for the Pacific channels. Or End to end calibrations are not being used and the user wants better results than the RSS specified for the Pacific channels.. Or When the user wants to ensure that the factory alignments of the channels have not varied in an undesirable fashion. Or When the user wants to investigate channel linearity across the full input range for a channel or channel(s). Or If the user is using the ICS-610 high speed sigma delta A to D converters and end to end calibrations are not being performed. The reader should note that properly function channels from Pacific will have linear slopes, and that drift offsets are taken out using Pacific s automatic zero hardware algorithm. If the user decides to perform a voltage calibration then he will use the Voltage Calibration Dialog Box. The user can get to the voltage calibration dialog box by using the Test\Calibration\Amplifier Calibration menu item or from one of the many buttons on other dialog boxes. When the user selects Voltage Calibration the following dialog box appears

60 In the example figure all of the channels have failed voltage calibration since voltage calibration has not been performed yet. The important errors are indicated by circles with numbers on them. Scott is working here Area one shows the names of the channels that are in the test. If the user clicks the right side mouse button over a channel name then the software will spawn the Channel Parameters dialog box for that channel. In area one either a graphic red frowning face or a green OK icon will be shown. A red frowning face indicates that the voltage calibration incurred an error. The error type is shown in area 2 of the dialog box. Icons indicate the type of error. their meanings. The icons are shown below with Shows a flat line error Shows an over range error Shows a single step non-linearity error Shows a noise error Shows a slope error (ie. too far away from 1.00 non-dimensional) Shows an offset error Shows a calibration that has no errors Area three lists the means and deviations for all the voltage calibration data steps performed. The means and deviations are indicated in mv RTI (referenced to input) which means that they are the actual mv readings that could be measured out of the EDC. If a calibration step is noisy then the deviation area will show a sigma squared icon which indicates that there is a deviation error. The software does not record the voltage calibration data to separate files (as it does for EU calibration). It does save the means and deviations in the test file when the user saves the test file. Area four is actually to the right of where indicated in the figure. It shows the voltage slope and voltage offset for each channel. If a channel fails voltage calibration then the slope is defaulted to 1.0 and the offset is defaulted to 0.0. The voltage calibration process is a non-interactive process. Area 5 in the figure shows the status window for the calibration. When the user begins a calibration the software looks at the channels selected, sorts them by gain, and performs calibrations on groups of channels having the same gain at the same time. The status window is updated to show the user the progress. Further, in area 9 a button appears (Stop Button) that allows the user to interrupt the voltage calibration. The software communicates with the EDC522 via the GPIB interface. The EDC 522 has a GPIB address, and that address is shown in area 6 of the diagram. Please make sure that the EDC address matches the address shown in area 6. Proper addresses range from 1 to 31, and the address should not be the same address as that of the Pacific 6000 system. At this time there is no mechanism in place for using other than the EDC 522. This is because the EDC 522 offers good performance for reasonable cost. Area 7 shows the gain and offset tolerances for the voltage calibration. Gain and offset (ie. slope and offset) are checked on the voltage calibration but they have no meaning for EU calibrations (as far as the software is concerned since it has no real concept of the many different gages the user can connect). In the example above the slope and offset tolerances are set to 5%. If the user is using Pacific Instruments digitizers only then he should set these numbers to 0.07 % or slightly lower since the automatic calibration of the Pacific Instruments channels leads to very accurate results without daily voltage calibrations. If, however, the user is using the high speed ICS-610 sigma delta digitizers then the numbers shown in the figure should be used. Note, the difference in slope and offset accuracy between the Pacific Instruments digitizers and the ICS digitizers is completely taken care of by the voltage calibration, and both digitizer components exhibit extremely good results when used properly. Area 8 in the figure above shows buttons that can be used to scroll the contents of the list control all the way right (to slope and offset) or all the way left (to channel name). Area 9 contains the buttons that start and stop the voltage calibration process. A begin button is shown in the figure. When the user begins the voltage calibration a stop button is shown next to it. The user is encouraged to let the voltage calibration process proceed until it has finished. Channels are calibrated in groups where the groups of channels are determined by channels that have the same gain (and thus voltage levels for voltage calibrations). PI660 will use the results of the voltage calibration process to calculate the Slope V coefficient of the voltage calibration conversion equation. The offset of the voltage calibration will be shown in the table areas indicated by area 4, but this offset will not become the offset coefficient of the Voltage Calibration conversion equation. This offset is the offset of the Voltage Calibration Input path, and is not as accurate as the offset acquired via automatic zero and zero plug calibration. The zero offset listed in the table is used for a linearity comparison of the voltage calibration values obtained during Voltage Calibration. 60

61 Area 10 contains a button that allows the user to spawn the shorting plug calibration dialog box. Shorting plug calibration is a type of calibration that allows the user to obtain better results than are indicated by the Pacific Instruments specifications (widely available). Area 11 contains a button that allows the user to spawn the dialog box for controlling an Agilent Model 33120A programmable function generator. The dialog box is shown below. It allows the user to select the function generator s output waveform, frequency, peak to peak waveform amplitude, and DC offset. It also allows the user to select the GPIB address that the PI660 software should use to communicate with the function generator (ie. the function generator s GPIB address). Please refer to the Agilent 33120A user manual for more information about the specifics of the function generator operation. When this dialog box is spawned it shows the current settings of the generator if the generator is found on the GPIB bus. In the figure below the generator was not found. Area 12 contains buttons that allow the user to select (highlight) different groups of channels for voltage calibration. Similarly, area 13 contains a button that allows the user to select only the channels that are being backed up automatically by a PI660 backup system. Area 14 contains two radio buttons that allow the user to specify if he is using the integrated EDC 522 voltage calibrator as the voltage source or not. If he is not then during each step of voltage calibration PI660 will instruct the user (via message box) as to the voltage to select on his voltage source. Note, voltages requested by PI660 may not make entire sense to the user since PI660 uses the attenuator circuit on each channel as often as possible. This is due to the fact that programmable precision voltage sources generally are more accurate at higher voltage levels. 61

62 Engineering Unit Calibrations Users of the 6000 system may choose to perform Engineering Unit (EU) calibrations. When they perform EU calibrations they are interacting with PI660 so that it generates slope and offset coefficients for the EU conversion equation. PI660 does not calculate second or third order coefficients when it performs EU calibrations. Users can perform AC and DC EU calibrations with PI660. They do not have to perform calibrations if they are using lookup tables or entering the EU conversion equation coefficients explicitly. To perform an EU calibration the user needs to setup the characteristics of the EU calibration for each channel. PI660 has a number of different utilities to help in this setup. Channel Engineering Unit Calibration Setup In the 6000 DAS there are two distinct types of calibration that are performed. The first type is voltage calibration, and the second type is engineering unit calibration. Voltage calibration is discussed in the previous subsection of this manual. Engineering unit calibration is the process by which the software determines the conversion equation coefficients that are used to convert voltages measured to engineering unit quantities. This software provides three types of engineering unit conversion equation determination. The first type uses a least squares fit and includes all data points acquired to fit an equation to the calibration data. The second type uses a straight-line fit of two points of calibration data to determine the engineering unit conversion equation. The two point calibration technique checks each calibration point to determine if the data acquired for each point conforms to the tolerances the user has set for single point linearity. The software uses these checks to determine which of the calibration points to use along with the zero point to generate the equation of the line. The third type of engineering unit conversion equation determination is the lookup table. The lookup table contains piecewise linear line segments that convert mv values from the Voltage Conversion Equation into EU values. The user of PI660 determines which EU conversion equation determination method to use by making a selection for each channel from within the channel definition dialog box. See figure 7 of this manual for a description of how to choose the type of EU conversion equation determination for each channel. The following figure shows the calibration setup dialog box as it appears for channels using the least squares fit calibration technique. The calibration details dialog box contains very few controls when it is shown for a channel that uses least squares fitting of data. The user can select from the standard calibration types for the channel. Among the standard calibration types is a type of calibration known as freeform calibration. This type of calibration completely matches the types of calibrations available in previous versions of PI

63 The following figure shows the calibration details dialog box for a channel that uses a two point straight-line fit. The extra controls at the bottom of the dialog box (in area one) pertain to special cases of the two-point calibration technique. They are represented in the dialog box as special options The dialog box also presents the non-standard calibration type. The controls to setup the non-standard calibration type are located in area two of the above figure. Standard Calibration Types The PI660 software provides what are known as standard calibration types. A standard calibration type is a pre-defined set of calibration states and percentages of full-scale input that they represent. A standard calibration type can be associated with any channel that is in the test. The software provides 200 user definable standard calibration types. Area three in the above figure shows the button that the user clicks to define a standard calibration type. When the user clicks the button the following dialog box appears. 63

64 The standard calibration type definition dialog box allows the user to define the input states and the percent of full scale that they represent for up to eight calibration steps. It also allows the user to give each standard calibration type a name and to copy standard calibration type information between one standard calibration type and another. Area one in the standard calibration type dialog box contains a combo box for choosing the standard calibration type to define and an edit field for entering a name for the standard calibration type. The name can be up to 32 characters in length. Area two in the standard calibration type dialog box contains a set of eight combo boxes that allow the user to select a calibration state for up to eight calibration steps. Different Pacific Instruments signal conditioning units allow different input states. The user should get familiar with the input states suitable for each of his signal conditioner types. An input state is one of the following State Name Description Models Supported Transducer Input Normal channel input where the gage All (transducer signal flows through the channel to the digitizer and then on to the computer) Zero Cal Transducer disconnected from the All Analog Models amplifier, and the amplifier positive and negative inputs shorted together and connected to excitation common. Voltage Cal * 1.0 Transducer disconnected from the All Analog Models amplifier and the voltage calibration bus unattenuated connected to the amplifier. Voltage Cal * 0.1 Transducer disconnected from the All Analog Models amplifier and the voltage calibration bus divided by ten connected to the amplifier. Voltage Cal * 0.01 Transducer disconnected from the All Analog Models amplifier and the voltage calibration bus divided by 100 connected to the amplifier. Shunt 1 Bridge transducer shunted by the first 6033, 6032, 6030, 6120 onboard shunt resistor for the channel Shunt 2 Bridge transducer shunted by the 6032, 6030, 6120 second onboard shunt resistor for the channel Shunt 3 Bridge transducer shunted by the third 6120 onboard shunt resistor for the channel Shunt 4 Bridge transducer shunted by the fourth onboard shunt resistor for the channel

65 Excitation Interrupt Excitation Voltage Monitor Excitation Current Monitor Transducer input connected to the amplifier, but the excitation turned off. (Good for looking at noise on signal lines) Transducer input disconnected, and scaled down excitation voltage applied to digitizer input Transducer input disconnected, and amplified excitation current (converted to voltage) applied to digitizer input 6032, 6030, , 6030, , 6120 Area three of the figure above shows a set of eight edit controls that allow the user to enter the percent of full scale that the input stimulus should represent for each calibration state. This percent of full scale is used when the user applies a standard calibration type to a channel input to determine the equivalent engineering unit value for each calibration step for the channel. For example, if a channel has a full scale input value (defined in the channel definition dialog box) of 2000 g s then the standard calibration shown in the above figure would yield equivalent engineering units of zero g s for the first calibration step, 200 g s for the second calibration step, 500 g s for the third calibration step, 1000 g s for the fourth calibration step, 1500 g s for the fifth calibration step, and a return to zero g s for the sixth calibration step. When engineering unit calibration is performed on a channel the software places the channel in the first calibration state and records 512 samples of data. The data are then checked for overloads. Any point that overloads in the 512 points of data flags the step as overloaded. The software then proceeds to the next step and repeats the process for as many steps as are defined for the channel. When the software finishes all of the steps it calculates a slope and offset for the channel using either a least squares fit of all steps acquired or a two-step straight line fit depending on the fit type associated with the channel. The result of the engineering unit calibration is an equation that maps mv to engineering units for the channel. The equation is a straight line equation consisting of a slope and offset. Please note that if any of the calibration checks for the channel fail the slope will automatically be set to unity, and the offset will be set to zero. Calibration checks are discussed later in this manual. Area four in the figure above contains a button that allows the user to copy the definition of one cal type to another. Typically cal types are setup once for the software, and they are not modified very often. The copy button spawns a dialog box in which the user can copy selected information from one standard calibration type to another. Area five in the figure above shows how to set a calibration step as unused. All unused steps must be at the end of the standard calibration. If the user places an unused step prior to one that is used the software will mark all calibration steps after the first unused step as unused. When the user finishes defining standard calibration types the software will check all channels in the test to see if they need to be updated. If a standard calibration type changes to include input states that are not valid for certain channels, and if those channels are marked as using the changed standard calibration type then those channels will be reset to the freeform standard calibration type, and their input states for all steps will be set to transducer input. Further, these channels will be marked as having no calibration steps. This means that the user will have to redefine the calibrations for these channels. Least Squares Fit Engineering Unit Calibrations The least squares fit method of engineering unit calibrations is the standard Pacific Instruments calibration method. All previous versions of PI660 used this method. In a least squares fit calibration the software acquires all steps of calibration data that are associated with the channel being calibrated and then performs a least squares fit on the data. The least squares fit provides a slope and offset for a line that best fits the calibration data acquired. Each step of the calibration yields a mean value in mv referenced to input (RTI) and a standard deviation of the 512 values acquired. Through calibration setup the user has defined the equivalent engineering unit (EU) value for each step. Thus, the software has point pairs that consist of (mv, EU) (x,y) for each step of calibration data. The point pairs then are used to construct a line. The line is the best line that fits through all of the points. It is not required to exactly connect any of the points, however. For this reason, the two-step straight-line calibration is also provided. It does exactly connect two points of the calibration data acquired. Two-Step Straight-Line Engineering Unit Calibrations The two-step straight-line engineering unit calibrations are provided for those users that require the calibration equation to exactly connect two points of calibration data acquired. It is up to the user to determine which method best applies to their needs (two-step straight-line or least squares). The two-step straight-line engineering unit calibration method is performed by the PI660 software exactly as is the least squares engineering unit calibration. The difference between the two is in how the equation of the line fitting the calibration data is determined. In the two-step straight-line engineering unit calibration the software looks through the step data acquired and tries to fit a line between the step representing the highest engineering unit value and the step(s) 65

66 representing the lowest engineering unit value. The lowest engineering unit value step can be the average of what are known as the zero step and the return to zero step. This will be discussed later, but suffice to know that the software allows for hysteresis calibration where two steps of calibration data are acquired that both represent the zero engineering unit condition. When the software tries to fit a line between the highest EU calibration step and the lowest EU calibration step it determines a line between the two steps and then checks the other steps (between the highest and lowest) for nonlinearity. If it is found that more than one non-linear step occurs when the other steps are checked against the line then the software rejects the highest EU value step as non-linear and moves to the next highest step and repeats the process. The software continues this checking until it finds a calibration step that can be used as the highest that yields no more than one non-linear step and no less than three linear steps. If the software can not find a step that passes then the calibration is rejected as a failure and the user is alerted. The EU conversion equation slope and offset are then reset to default values or 1.0 and 0.0 respectively. The two-step straight-line calibration allows the user to select several special options. The special options generally determine how the software performs its analysis of the calibration data acquired and how it determines rejection of calibration data. The calibration setup dialog box is shown below, and the reader should note the special options area of the dialog box Special option zero (in area 1 above) means that the software processes the calibration data normally for a two-step straight-line calibration. Normal processing of this data is discussed in the previous paragraph. The only anomaly about special option zero to remember is that the zero step data will either be from a single calibration step that equates to zero EU or from the average of two calibration steps that equate to zero EU. The zero value will be the average of two steps if two zero EU steps exist in the calibration. It will be from one value if only one zero level EU steps. 66

67 Special option 1 (area 2 in the above figure) tells the software that the first step is not really at zero EU value although the calibration setup indicates that it is. This is a situation that typically arises due to a gage that is experiencing a load due to its location on the test article, and that load can not be removed from the gage for calibration. Since the software performs a single-step non-linearity analysis on the data from the calibration for the channel the non-removable load will make the calibration fail as non-linear if the load is not accounted for. The software performs the calibration as it normally does (calculating a slope and offset based on the EU values and mv readings of the calibration steps), but when the software checks for single step non-linearity all steps readings (mv) are adjusted by the amount of the zero step reading. For example, if the zero step has a reading of 2000 mv then 2000 mv is subtracted from each step when the software analyzes single step non-linearity. Note, the slope and offset are determined by the zero, return-to-zero, and highest linear point from the calibration step. Special option 3 (area 3 in the figure) tells the software that the channel undergoes a single point AC calibration. During an AC calibration a sine wave is applied to the channel through the proper input path. The proper input path is chosen by the user when the user defines the calibration state for the single calibration step for the channel. Typically users will use the voltage calibration input path un-attenuated. The software takes the peak to peak mv value that the user specifies in the edit field associated with the AC Cal as information about the source input wave that the user wants supplied to the channel. The software determines the frequency of the waveform to apply to the channel based on the sampling rate that the channel is using for the test. The software determines what frequency of sine wave will provide 7 full cycles of sine wave data in 512 points of acquisition. When the software performs an AC calibration on a channel it programs the AC function generator to the proper signal output (sine wave at the user s requested peak to peak amplitude and the 7 cycle frequency), acquires the data from the channel, determines the maximum and minimum values of the sine wave, and calculates an rms value for the resulting sine wave based on these max and min values. A slope is then calculated from the rms data calculated and the rms data value expected from the waveform generated. That slope is then applied to the mean mv value of the data acquired for the signal to determine an offset that is in engineering units for the EU conversion equation. Special option 4 (area 4 of the figure above) allows the user to tell the software to override the zero offset with a user supplied value. This special option is a case that handles a calibration where the user wants slope calculated based on the data acquired for the calibration, but where the user wants the offset calculated based on some other mv value. The software acquires the data for the calibration steps and analyzes it normally. It then uses the calculated slope and the user supplied zero override value (in mv RTI) to calculate a new offset. Special option 5 (area 5 of the figure above) indicates to the software that the user wants to force the calculation of the slope of the EU conversion equation using step 1 (the zero EU step typically) and some other step. In this case the first step of the calibration is assumed to be zero EU for the basis of calculating slope. So, the slope is calculated using step 1 of the calibration data and the user s selected step where step 1 is assumed zero mv. The offset is then calculated from the resulting slope being applied to the mv value obtained during the return to zero step of the calibration. Special option 6 (area 6 of the figure above) indicates to the software that the user wants to calculate the equation based on the fact that the first step is not really zero engineering units. The user enters the engineering units value for the first step in the edit field provided for the area. The software calculates the slope of the engineering unit conversion equation using the data acquired in the normal fashion. It then uses the slope in EU per mv and applies it to the user s entered non-zero step one engineering unit value. That value is converted to a mv RTI value based on the slope from the acquired data. The mv RTI value is subtracted from the average of the zero EU step mv and the return-to-zero step mv. The result is then multiplied by the slope to get an offset in Engineering Units. Special option 8 (area 7 of the figure above) allows the software to use only the first zero step, not the average of the first zero step and return to zero step, in determining the slope and offset of the engineering unit conversion equation. The only difference between this conversion and the normal conversion is that there is no averaging of two zero steps. Special option 9 (area 8 of the figure above) is exactly like special option 6 except for the fact that the return to zero step is not averaged together with the zero step to create the initial offset of the engineering unit equation. Non Standard Cal Type A Non-standard calibration type is simply a two-point calibration that the software can use when performing the two-point straight-line engineering unit conversion equation determination method. The non-standard calibration type is really nothing more than freeform calibration where two points are used. When the user selects non-standard calibration type the software enables two controls that allow the user to select which step of the calibration for the channel is the zero step, which step is the other step used with the zero EU step to construct the engineering units conversion equation, and what the value of the non-zero step is in terms of percentage of full scale. The software constructs a two step calibration for the user, and allows the user to select either the first step as the zero step or the second step as the zero step. Engineering Unit Calibration Failure Analysis 67

68 The PI660 software performs five checks on engineering unit calibration data acquired. Some of the checks focus on individual calibration steps, and some of the checks focus on the whole collection of calibration steps. The checks are performed regardless of whether or not the user is using two-point straight-line engineering unit conversion equation calculation or least squares fit engineering unit conversion equation calculation. The user can disable error information coming from the checks by setting the tolerances on the checks to large numbers. In order of decreasing severity the software checks Check Flat Line Error Over Range Error Hysteresis Error Single Step Non-Linearity Error Noise Error Description Using Two-Step Straight- Line Fit This check of the calibration data looks for calibrations in which the first non zero calibration step mv reading does not deviate from the zero calibration step mv reading by a user determined percentage of full scale. If the first non zero calibration step fails the flat line check the calibration is not failed unless none of the other calibration step mv readings differ from the zero step mv calibration reading by more than twice the user determined percentage of full scale. This check of the calibration data looks to see if the second lowest step, the first non-zero step, reading in mv is above the user s prescribed limit of full scale. The software also looks at all points of the 512 points acquired and if any of them actually overload the amplifier then calibration will flag the step as overrange. This check of the calibration data looks for two EU steps in the calibration that represent Zero EU value. If there are two cal steps that represent zero EU value then the software treats the steps as zero and return-to-zero steps. It compares the mv readings for the two steps, and if they differ by more than the user prescribed tolerance then the calibration is flagged with a hysteresis error. This check of the calibration data looks to make sure that the calibration data acquired yield at least three linear steps of data. The software determines which two points of calibration step data to use based on this check. It tries to use the step with the highest EU value associated with it along with the zero step to make the equation of the line. It will successively try steps lower in EU value than the highest value if the calibration fails using the highest EU value step. This check of the calibration data looks at each step and determines if any step is noisier than the user s prescribed limit on noise Description Using Least Squares Fit This check of the calibration data looks for calibrations in which any of the mv readings for cal steps that differ in EU values from the first cal step do not differ in mv reading from the first cal step s mv reading by more than a user specified percentage of full scale input for the channel. This check of the calibration data looks for any steps in the calibration that come within a user prescribed limit of full scale. This checks the mean value of the step. The software also looks at all points of the 512 points acquired and if any of them actually overload the amplifier then calibration will flag the step as overrange. This check of the calibration data looks for two EU steps in the calibration that represent Zero EU value. If there are two cal steps that represent zero EU value then the software treats the steps as zero and return-to-zero steps. It compares the mv readings for the two steps, and if they differ by more than the user prescribed tolerance then the calibration is flagged with a hysteresis error. This check of the calibration data looks to make sure that the calibration data acquired yield at least three linear steps of data. Being a least squares fit this check has no bearing on determination of the equation for EU conversion. This check of the calibration data looks at each step and determines if any step is noisier than the user s prescribed limit on noise The software will show the results of any errors using graphics that describe the highest level of error. The following show the graphics that depict the errors. Shows a flat line error Shows an over range error Shows a single step non-linearity error Shows a hysteresis error 68

69 Shows a noise error Shows a calibration that has no errors The results graphics are shown on two dialog boxes. They are the Engineering Unit Calibration dialog box and the Specific EU Calibration Details dialog box. The Engineering Unit Calibration dialog box is used to perform engineering unit calibrations. It is shown below. In the figure above a single channel is being engineering unit calibrated, and the results up to the current point indicate a flat line failure. If the user clicks the right hand mouse button over the flat line failure icon then the Specific EU Calibration details dialog box will appear. It is shown below for the above flat line calibration error. The Specific EU Calibration Details dialog box contains information that allows the user to determine the failure cause for a channel calibration. The dialog box is shown in the following figure. 69

70 In the figure above the channel named Accel has failed EU calibration since it has flat lined calibration data. The software also indicates that this calibration data would fail with a single step linearity error if it were not flat line failed. The software has reset the slope and offset of the engineering unit conversion equation to 1.0 and 0.0 respectively. Performing Engineering Unit Calibrations Once the user has setup engineering unit calibrations for a channel or channels he may perform the engineering unit calibrations. To perform the calibrations the user selects the EU Calibration menu item. When he selects this menu item the following dialog box is shown. 70

71 The Engineering Unit Calibration Details dialog box shows the details of the EU calibration setup and results for the channels in the test that can be calibrated. Some channel types (such as the 6013 reference channel) have integral calibrations and do not need to be calibrated by the software. The figure above has ten areas of interest highlighted. The first area shows the name of the channel and an icon that indicates whether or not the calibration has failed or passed. The following icons are used Means the channel passes EU Calibration Means the channel failed EU Calibration If the channel failed calibration the reason for the failure will be presented in area 2 of the figure above. Clicking the right hand mouse button above a channel name in the first column will cause the software to show the Channel Setup dialog box. Clicking the right hand mouse button above a failure reason in the second column will cause the software to show the Specific EU Calibration Details dialog box that shows more details about failed calibrations. Area three in the dialog box lists the name of the standard calibration type and shows an icon indicating if the calibration is a DC calibration or an AC calibration. The following icons are used: Indicates the calibration is an AC Calibration Indicates the calibration is a DC Calibration Indicates the channel does not have a calibration defined Clicking the right hand mouse button above a calibration type in area three will display the Calibration Setup dialog box for the associated channel. Area four in the dialog box lists all of the means and standard deviations for the calibration steps. The values are in mv RTI. Clicking the right hand mouse button above a mean or deviation will spawn the Calibration Step Plot dialog box. 71

72 The Calibration Step Plot dialog box allows the user to review the actual calibration data acquired for the channel graphically. It is discussed in a different section of this manual. Area five in the dialog box contains a button that allows the user to perform voltage calibrations on channels in the test. Voltage calibration is discussed in a different section of this manual. Voltage calibration is the only calibration necessary for thermocouples since they use table lookup as a conversion to engineering units. Area six in the dialog box contains a button that allows the user to actually begin performing DC style engineering unit calibrations. The user should highlight some channels in the dialog box before clicking the button in area six. When he clicks the button the highlighted channels will be displayed in a new dialog box. In that dialog box the user can either interactively step through the DC calibrations or instruct the software to perform the DC calibrations automatically. Area seven in the dialog box contains a button that allows the user to begin performing AC style engineering unit calibrations. The user should highlight some channels in the dialog box before clicking the button in area seven. When he clicks the button the highlighted channels will be displayed in a new dialog box. In that dialog box the user can instruct the software to perform the AC calibrations automatically. Area eight in the dialog box contains the edit controls that allow the user to specify the limits on the calibration checks that are performed. Please note that these limits are used for voltage calibrations also. The limits are entered as percentages of full scale for the channels. The limits apply to all channels. If the user changes a limit the software will recalculate the EU conversion results. Area nine in the dialog box contains a button that will spawn a dialog box wherein the user can load the calibration results from a previous calibration file. Each time an Engineering Unit calibration is begun (as denoted by clicking the button in area six of the above dialog box) a calibration file (.cal) is created. The calibration file contains the actual calibration data acquired for the channels. The data acquired consist of 512 point calibration steps as well as means and standard deviations for the steps. The dialog box that loads calibration data previously acquired gives the user a listing of the calibration files in the current test directory. If the user chooses to import a calibration file then all of the calibration information from the file will be applied to all of the channels that had calibration data acquired during the associated calibration that the file was generated during. This option is not normally performed, but it is there as a utility. The user should review the section on the Calibration Step Plot dialog box for information on a more controlled mechanism of importing previous calibration data. The Calibration Step Plot dialog box allows the user to import individual calibration steps or full calibrations for individual channels from the calibration files. Area ten contains a button that spawns the report gallery dialog box. In the report gallery the user can make text output files of calibration results. Performing DC Engineering Unit Calibrations DC engineering unit calibrations are calibrations wherein the data for each calibration step is quiescent. It is not supposed to vary. The software imposes settling time between the acquisitions of calibration step data. These settling times will ensure that the channel has had enough time to allow the signal path time to become quiescent. To perform a DC EU Calibration the user starts with the Engineering Unit Calibration Details dialog box. In that box he highlights channels to calibrate and he clicks the EU Calibration button. When he clicks the button a dialog box appears that contains a listing of the channels the user has highlighted. The dialog box that appears is shown below. 72

73 The first area of the dialog box contains the name of the channel and an icon indicating if the channel calibration has failed or has passed. The following icons are used Means the channel passes EU Calibration Means the channel failed EU Calibration Clicking the right hand mouse button above a channel name in the first area of the dialog box will spawn the channel setup dialog box for the channel. The second area of the dialog box contains an icon indicating the reason for failure and a text string describing the failure or an icon indicating success. The following icons are used Shows a flat line error Shows an over range error Shows a single step non-linearity error Shows a hysteresis error Shows a noise error Shows a calibration that has no errors Means that the calibration is still being performed Please refer to the discussion of Engineering Unit Calibration Failure for a description of the errors and their causes. Area three of the dialog box shows the means and standard deviations for the calibration data acquired for the channel. When the dialog box is first initialized these values are left blank. This is since the dialog box will scroll to the right as calibration data are acquired for each step and it will fill in the results as the calibration is being performed. If the user needs to review the information about means and deviations he can click the button marked Scroll To Equation and the 73

74 information will be placed in the dialog box. Clicking the right hand mouse button above a mean or standard deviation for a channel will spawn the Calibration Step Plot dialog box where the user can see a plot of the data acquired for the step. Area four of the dialog box is noted to point out the fact that the spread sheet in the dialog box should be scrolled to the right to look at the slope and offset for the channels as well as the other step means and deviations for the channels. Area five of the dialog box contains a text control that shows the status of the calibration. When calibration begins the status text changes to show the user which step of the calibration is being performed and how many total steps are in the calibration. Please note that the software performs EU calibrations in parallel. Many channels may be calibrated at the same time. Alternatively, the user can perform calibrations on individual channels. Please continue reading to determine how to perform the calibrations. Area six of the dialog box contains a check box and an edit control. The check box and edit control are used when a user would like to assign an EU value for the step being performed to all channels. For example, the user calibrating a large number of pressure transducers that are all connected to the same pressure plenum where the pressure in the plenum can be varied and is known can enter the plenum pressure in the edit field for the step being performed and that EU value will be applied to all selected channels for the calibration step. This option is only available during interactive calibrations. Interactive calibrations are those in which the user tells the software when to proceed with each step of the calibration. Area seven of the dialog box contains the buttons for interactive calibration. In the figure above only two of the four buttons are shown. Not shown are the Back and Stop buttons. This is because the figure above was taken when a calibration had not been started. Performing an interactive calibration allows the user to perform steps of the calibration, skip steps, re-perform steps, etc. It is very flexible. When the user performs or skips the final step the slopes and offsets and failures are re-determined. Note, calibrations are only performed on the channels in the dialog box that the user highlights. In this way the user can perform calibrations on groups of channels, all channels, or individual channels at a time. Area eight of the dialog box shows the button used to begin non-interactive calibration. Non-interactive calibration is good for calibrations that employ calibration states such as resistive shunt or resistive substitution since these states can be performed without any user interaction. The user can use non-interactive for other calibration input states, he must make sure that the input stimulus for the state is synchronized with the acquisition of the data for the step. Non-interactive calibrations can be halted by clicking the Stop button (not shown in the figure but located adjacent to the begin noninteractive button). Area nine of the dialog box shows the buttons that control display scrolling. Since there are many columns shown in the spread sheet control these buttons are presented for convenience. Area ten of the dialog box contains a button that spawns the calibration setup dialog box for the first currently selected channel. The calibration setup dialog box is used to define the EU calibration for each channel. Areas 11, 12, 13, and 14 of the dialog box contain buttons that spawn the Specific EU Calibration Details, Calibration Step Plot, Agilent Function Generator Setup, and Report Gallery dialog boxes. The Specific EU Calibration Details dialog box can also be made visible by clicking the right hand mouse button over a channel entry in area two of the dialog box. The Calibration Step Plot dialog box can also be made visible by clicking the right hand mouse button over a mean or standard deviation entry in area three of the dialog box. Performing AC Engineering Unit Calibrations AC Engineering unit calibrations are single step calibrations in which a sine wave of known magnitude is supplied to a channel or channels. The rms value of the sine wave is known, and seven waveforms of the sine wave are acquired for each channel. Channels are calibrated sequentially during AC calibrations so the AC calibrations may take more time to perform than do DC calibrations. They are performed sequentially since each channel may require a different magnitude and/or frequency sine wave for the calibration. Please read the discussion of AC calibrations for more information on what they exactly do. To perform an AC EU Calibration the user starts with the Engineering Unit Calibration Details dialog box. In that box he highlights channels to calibrate and he clicks the AC EU Calibration button. When he clicks the button a dialog box appears that contains a listing of the channels the user has highlighted. The dialog box that appears is shown below. 74

75 The first area of the dialog box contains the name of the channel and an icon indicating if the channel calibration has failed or has passed. The following icons are used Means the channel passes EU Calibration Means the channel failed EU Calibration Clicking the right hand mouse button above a channel name in the first area of the dialog box will spawn the channel setup dialog box for the channel. The second area of the dialog box contains an icon indicating the reason for failure and a text string describing the failure or an icon indicating success. The following icons are used Shows a flat line error Shows an over range error Shows a single step non-linearity error Shows a hysteresis error Shows a noise error Shows a calibration that has no errors Means that the calibration is still being performed Please refer to the discussion of Engineering Unit Calibration Failure for a description of the errors and their causes. Note, if an AC Calibration shows a noise error this is not really an error since a sine wave is basically a non-quiescent (noisy) signal. Area three of the dialog box shows the sample rate for the channel. The sample rate is defined in either the Select Test Channels Dialog Box or in the Sample Rate Definition Dialog Box. 75

76 Area four of the dialog box shows the frequency of the sine wave being generated for the channel. The frequency is determined by the software so that seven cycles of a sine wave span the 512 samples of data taken for the channel. Area five of the dialog box shows the peak-to-peak mv of the sine wave being generated for the channel. The user selects this value in the Calibration Setup dialog box. Area six of the dialog box shows the RMS value of the wave form being generated. This is calculated based on the characteristics of the sine wave being used for the calibration. Area seven of the dialog box indicates an error next to it. This is to show that there is more information about the data that has been acquired for the channel(s). The columns to the right of area seven include input peak to peak mv acquired, input RMS calculated from input peak to peak acquired, input max mv acquired, input min mv acquired, input mean mv, offset and slope calculated. Please refer to the section describing AC Calibration setup for more information on the process used for AC calibration. Area eight of the dialog box tells the user the status of the calibration(s) being performed. It indicates channel being acquired, and some information about the waveform being generated. Note, the software will drive the Agilent function generator via the GPIB bus during the calibrations. Area nine of the dialog box shows the buttons that control display scrolling. Since there are many columns shown in the spread sheet control these buttons are presented for convenience. Area ten of the dialog box shows the button for beginning AC calibrations. The user should highlight one or more channel in the spread sheet control prior to beginning AC calibrations. Area eleven of the dialog box shows the button used to spawn the calibration setup dialog box for the first of the currently selected channels. This dialog box controls the definition of the calibration for the channels in the test. Area twelve of the dialog box contains controls that allow the user to turn on or off a digital output line in the 6000 system. Since the user most likely will desire to have the Agilent wave form generator and the EDC voltage source connected to the voltage calibration bus on the 6000 system there must exist a way to switch between them. Both sources cannot simultaneously be attached to the voltage input bus of the 6000 system. The user can provide a circuit that controls the switching of the two devices onto the voltage calibration bus. The circuit can be controlled by a digital output from a model 6040 digital I/O card in the 6000 system. The controls in this area allow the user to turn on or off the Digital Output line. Areas 13, 14, and 15 of the dialog box contain buttons that spawn the Specific EU Calibration Details, Calibration Step Plot, and Agilent Function Generator Setup. The Specific EU Calibration Details dialog box can also be made visible by clicking the right hand mouse button over a channel entry in area two of the dialog box. The Calibration Step Plot dialog box can also be made visible by clicking the right hand mouse button over one of the columns in area seven of the dialog box. Using Lookup Tables For EU Conversion PI660 contains 50 user definable lookup tables for Engineering Unit conversion. They can be used in lieu of the EU conversion equation when the user has a non-linear gage. Lookup table definition is performed via the Channel Definition Dialog box. Figure 7 shows the area of the Channel Definition Dialog box that allows the association of a lookup table to a channel. When the user chooses a lookup table conversion he can associate a lookup table with the channel. He can also create and modify lookup tables. The following figure shows the lookup table association dialog box. 76

77 Figure?. Lookup Table Selection Dialog Box Area one of Figure? contains a combo box that allows the user to select from channels in his test that are using the lookup table EU conversion style. The combo box will specify the current channel that the user is focusing on in Channel Definition dialog box as a default. This area also contains information about the channel s measurement type, gage type, engineering units, and card style it is. Area two of Figure? contains a combo box that allows the user to choose from one of the 50 possible user definable lookup tables. As the user changes the lookup table number in the combo box the information in area four of the dialog box will change to show the specifics of the lookup table. Area three of Figure? contains a button that allows the user to spawn the Lookup Table Definition dialog box. The user can use this dialog box to modify any user definable lookup table in the system. Figure?? shows the Lookup Table Definition dialog box. 77

78 Figure??. Lookup Table Definition Dialog Box Area one of the lookup table definition dialog box contains a combo box that allows the user to select which lookup table is to be modified. When he changes the selection in area one the information in areas two, three, and four will be modified and show the definition for the specific lookup table the user has chosen. Area two of the lookup table definition dialog box contains an edit field that the user types into the name of the lookup table. Lookup table names can be up to 256 characters in length. Area three of the lookup table definition dialog box contains a combo box that allows the user to change the number of point pairs the lookup table uses. The minimum number allowed is two, and the maximum number allowed is 30 per table. As the user modifies the number of entries used more or less controls will become visible in area four of the lookup table definition dialog box. Area five of the lookup table definition dialog box contains buttons with Xs on them. Clicking one of these buttons will remove the associated entry from the currently viewed lookup table, and will subsequently reduce the number of entries the table uses by one. Note, there are no X buttons next to entry one and two since they can not be removed. Area six of the lookup table definition dialog box contains buttons that will generate a report of the lookup table configuration(s) currently defined. A message box will appear asking the user if he wants to view the report file with Notepad. The report file is a tab delimited text file that is named based on the time and date generated. So, it is difficult to overwrite the file. This is an excellent way to keep track of settings during a test process. Lookup tables are checked for multiple Input values (left hand column), and the software will not allow for this. Further, the software will sort the lookup tables when necessary so, the user may see some values shift position. He can be assured that what he intends is what he will see. Lookup table definitions are saved to the file LookupTables.lut in the PI660 software s working directory. Further, the contents of the lookup tables are saved inside of each and every raw data files. In this fashion the raw data files remain stand alone for re-conversion of the raw data stored inside of them. Strain Gage Calculator PI660 contains a tool for calculating theoretical EU conversion equation coefficients and suggested maximum gains for channel s in the 6000 system that are making strain gage measurements. The tool allows the user to enter the strain gage resistance, line resistance to the strain gage, expected maximum full scale deflection of the strain gage during the 78

79 test, and the strain gage s gage factor. The strain gage calculator uses this information to calculate a suggested highest gain for the channel, the gage output in mvrti for full scale compression, and the gage output in mvrti for full scale tension. The user can use the tool to change the gain for selected channels. The strain gage calculator dialog box is shown in the following figure Figure Q. Strain Gage Calculator Dialog Box Area one of Figure Q contains a column that shows the names of the channels that are selected into the test and that have bridge gage types and strain gage measurement types. See the section on Channel Definition to learn how to assign these characteristics to channels. Each row in area one includes a graphic that summarizes whether or not the current gain for the channel is optimum for the channel. The following table summarizes the possibilities for the graphic. Graphic Meaning The gain that PI660 deems the best for this channel is the gain the user has selected for this channel and the 6000 channel hardware seems to have this gain downloaded to it. The gain that PI660 deems the best for this strain gage channel is not the gain the user has selected for this channel. PI660 may think that the user s gain is or is not downloaded to the channel already. The gain that PI660 deems the best for this strain gage channel is the gain the user has selected for this channel, but PI660 thinks that the software gain setting is not downloaded to the channel. Table Q. Strain Gage Calculator Graphics & Meanings Area two of Figure Q contains a column that shows the user s currently selected software gain for the channel and a graphic that indicates if PI660 thinks the user s selected gain is the optimum gain for this strain gage channel. The graphic means that PI660 is not happy with the user s selected gain for the channel. The graphic means that PI660 thinks the user s selected gain for the channel is the optimum gain to use. Area three of Figure Q contains a column that shows the optimum gain for the strain gage channels. The optimum gain is arrived at based on excitation voltage, gage resistance, line resistance, gage factor, and expected maximum full scale input for each strain gage. Area four of Figure Q contains a column that shows PI660 s calculated slope coefficient for the EU conversion equation for each channel. PI660 arrives at the slope coefficient based on excitation voltage, gage resistance, line resistance, gage factor, and expected maximum full-scale input for each strain gage. 79

80 Area five of Figure Q contains a column that shows the gage factor for each strain gage. The column contains a graphic that indicates the user can edit the column by clicking the right hand mouse button over an entry in the column. PI660 will spawn a dialog box in which the user can enter the gage factor for all channels highlighted at the current time. If the user highlights more than one row of strain gage channels and clicks the right hand mouse button over the column then the entry he makes for gage factor in the dialog box that is spawned will be applied to each highlighted channel. Figure Q1 shows the dialog box for entering a new gage factor. Figure Q1. Dialog Box For Entering A New Gage Factor Area six of Figure Q contains a column that shows the gage resistance for each strain gage. The column contains a graphic that indicates the user can edit the column by clicking the right hand mouse button over an entry in the column. PI660 will spawn a dialog box in which the user can enter the gage resistance for all channels highlighted at the current time. If the user highlights more than one row of strain gage channels and clicks the right hand mouse button over the column then the entry he makes for gage resistance in the dialog box that is spawned will be applied to each highlighted channel. Figure Q2 shows the dialog box for entering a new gage resistance. Figure Q2. Dialog Box For Entering A New Strain Gage Resistance Area seven of Figure Q contains a column that shows the line resistance for each strain gage. The column contains a graphic that indicates the user can edit the column by clicking the right hand mouse button over an entry in the column. PI660 will spawn a dialog box in which the user can enter the line resistance for all channels highlighted at the current time. If the user highlights more than one row of strain gage channels and clicks the right hand mouse button over the column then the entry he makes for line resistance in the dialog box that is spawned will be applied to each highlighted channel. Figure Q3 shows the dialog box for entering a new line resistance. Figure Q3. Dialog Box For Entering A New Line Resistance Area eight of Figure Q contains a column that shows the full-scale ustrain expected for each strain gage. The column contains a graphic that indicates the user can edit the column by clicking the right hand mouse button over an entry in the column. PI660 will spawn a dialog box in which the user can enter the full-scale ustrain for all channels highlighted at the current time. If the user highlights more than one row of strain gage channels and clicks the right hand mouse button over the column then the entry he makes for full-scale ustrain in the dialog box that is spawned will be applied to each highlighted channel. Figure Q4 shows the dialog box for entering a new full-scale ustrain. Note, the new full-scale 80

81 ustrain for strain gage channels is analogous to the full scale measurement quantity defined in the Channel Definition Dialog box. The number of digits after the decimal point that the user enters in Figure Q4 will determine the number of digits of precision displayed for the channel(s) on PI660 s data displays. Figure Q4. Dialog Box For Entering A New Full-Scale EU Value Area nine of Figure Q shows the currently selected excitation voltage for each strain gage channel. Excitation voltage is defined in the channel definition dialog box for each channel. The user can spawn the channel definition dialog box by clicking the right hand mouse button over the first column (area one of Figure Q) of the Strain Gage Calculator Dialog Box. Area ten of Figure Q contains values that PI660 calculates for each strain gage. The values include full scale compression mv output of the gage, full-scale compression resistance of the gage, full-scale tension mv output of the gage, and full-scale tension resistance of the gage. The user must scroll the form using the scroll bar to see all the quantities. The quantities are derived based on the gage factor, gage resistance, line resistance, gage full-scale expected, and gage excitation voltage. The values are used to determine the highest gain the channel can use for the expected full-scale. Area eleven of Figure Q contains a status information area. PI660 summarizes the status of all strain gages in the test and places text in this window. The user can not edit this status text. Area twelve of Figure Q contains buttons that help the user highlight strain gage channels without having to use the Windows extended select (control, shift, click) mouse operations. The buttons allow the user to select channels not showing the graphic (Select Bad), all channels (Select All), and channels that are part of the seamless backup system s channels (Select Backups). Operations performed in the Strain Gage Calculator dialog box are performed on selected (highlighted) channels only. Area thirteen of Figure Q contains a button that allows the user to move the gains from column three (area three in Figure Q) into column two (area two in Figure Q). This means that the user is selecting PI660 s suggested best gains for the channels that are highlighted. This does not mean that the new gains will be sent to the channels. Typically, the graphic in column one will change from to indicating that the user s selected gains match the optimum gains, but that they have not been downloaded to the channels. Area fourteen of Figure Q contains a button that instructs PI660 to select (highlight) all strain gage channels that have the graphic listed in their first column of the dialog box. This readies the user to simply click the button in area fifteen of Figure Q to download the gains to the channels. This feature eases the setup of the channels significantly. Area sixteen of Figure Q contains a button that spawns the Automatic Bridge Balance Dialog Box. The Automatic Bridge Balance Dialog Box is discussed in the next subsection of this manual. Automatic Bridge Balance Tool The Automatic Bridge Balance Tool in PI660 is used to perform hardware based bridge balances on bridge type gages. The 6000 series channel modules containing bridge completion input circuits and bridge balance circuits can automatically remove quiescent bridge offset voltages by injecting small voltages into the bridges themselves. The Automatic Bridge Balance Dialog box is shown in Figure R. 81

82 Figure R. Automatic Bridge Balance Tool Dialog Box Area one of Figure R contains a column that lists the channel names and a graphic that indicates if the latest bridge balance information (in particular the Post Balance mv shown in area four of Figure R) is within the user s specified tolerance of zero. The user specifies his tolerance using the dialog box that is spawned by clicking the Define Tolerances button shown in area twelve of Figure R. If the Post Balance mv is under the specified percentage of the channel s full scale input range then the channel bridge balance is said to be good. If it is not then the channel s bridge balance is said to fail. If a channel passes then it will have the graphic shown in column one. If a channel fails then it will have the graphic shown in column one. Clicking the right hand mouse button over column one spawns the Channel Definition dialog box for the channel. Area two of Figure R contains a column that lists the Status of the bridge balance. This information follows the graphical status indication shown in column one. Areas three, four, and five of Figure R show the balance information for the channels in mvrti. This information is not stored in the channel. It is gathered when the user performs an automatic bridge balance by clicking the button in area eleven of Figure R. So, the information displayed in the columns may have been gathered at some earlier time. When the user performs an automatic bridge balance PI660 reads the starting mvrti value for the channel, instructs the channel s firmware to perform an automatic bridge balance, reads the post balance mvrti value for the channel, and calculates the difference (delta) for the channel. The resulting information is placed in columns three, four, and five of the Automatic Bridge Balance dialog box. The information is also stored with the test file when the user saves the test. Areas six, seven, and eight of Figure R show the balance information for the channels in Engineering Units (EU). This information is not stored in the channel. It is gathered when the user performs an automatic bridge balance by clicking the button in area eleven of Figure R. So, the information displayed in the columns may have been gathered at some earlier time. When the user performs an automatic bridge balance PI660 reads the starting mvrti value for the channel, instructs the channel s firmware to perform an automatic bridge balance, reads the post balance mvrti value for the channel, and calculates the difference (delta) for the channel. The resulting information is converted to EU using the user s EU conversion equation or lookup table for the channel, and it is placed in columns six, seven, and eight of the Automatic Bridge Balance dialog box. The information is also stored with the test file when the user saves the test. Area nine of Figure R shows a summary of the automatic bridge balance statuses for the channels currently selected into the test that are bridge type channels and that have automatic bridge balance enabled. The status is useful in cases where the user has more channels than can be shown in the space allotted by the Automatic Bridge Balance Dialog Box s spread sheet area. The spread sheet area will add a vertical scroll bar if there are more channels in it than are shown with one page. The status is simply a convenience. 82

83 Area ten of Figure R contains buttons that help the user highlight channels without having to use the Windows extended select (control, shift, click) mouse operations. The buttons allow the user to select channels not showing the graphic (Select Bad), all channels (Select All), and channels that are part of the seamless backup system s channels (Select Backups). Operations performed in the Automatic Bridge Balance dialog box are performed on selected (highlighted) channels only. Area eleven of Figure R contains a button that instructs PI660 to perform an automatic bridge balance operation on the channels currently selected (highlighted) in the spreadsheet. All channels selected will perform bridge balance operations in parallel with each other. This is a feature of the 6000 system s hardware and significantly reduces the amount of time it takes to perform bridge balance. The firmware for each channel performs the bridge balance on the channel. The firmware knows the filter cutoff frequency for the channel, and it will allow a longer settling time for channels using low values of cutoff frequency filter. Automatic Bridge Balance should take less than seconds to perform for all channels selected. If all channels are using high cutoff frequencies or operating in a wideband (unfiltered) mode then automatic bridge balance will take about 1-2 seconds to perform. Area twelve of Figure R contains a button that allows the user to define the tolerances for the PI660 software. One of the tolerances the user can define is the Automatic Bridge Balance tolerance. The tolerance is used by PI660 to determine which channels pass and which channels fail the automatic bridge balance process. Figure S shows the tolerance definition dialog box. Select Automatic Bridge Balance Tolerance Here Figure S. Calibration Error Bound Definitions Area thirteen of Figure R contains buttons that allow the user to create a text file that contains the current automatic bridge balance results and to clear (zero) the results. The result file is created when the user performs an automatic bridge balance using the button in area eleven of Figure R. If the user has not performed an automatic bridge balance then the report file will not exist. Tare Calibration For certain types of measurements it makes sense to remove an offset prior to performing a test. This offset removal is generally known as tare removal. PI660 contains a tool that allows for tare removal. The user can tell PI660 that the current value measured for a channel or group of channels (in mvrti) should be equated to a certain Engineering Unit (EU) value. When the user performs a tare calibration with PI660 he is instructing PI660 to change the offset coefficient(s) of the engineering unit conversion equation(s) for the currently selected channel(s). Figure T shows the Tare Calibration dialog box. 83

84 Figure T. Tare Removal Dialog Box Area one of Figure T contains a column that lists the channel names and a graphic that indicates if the current value of the channel input is within the tare percent tolerance of the EU value shown in area seven of Figure T. The user specifies his tolerance using the dialog box that is spawned by clicking the Define Tolerances button shown in area eight of Figure T. If the current value measured, in EU, is under the specified percentage of the channel s full scale input range away from the EU value listed in area seven then the channel tare is said to be good. If it is not then the channel s tare is said to fail. If a channel passes then it will have the graphic shown in column one. If a channel fails then it will have the graphic shown in column one. Clicking the right hand mouse button over column one spawns the Channel Definition dialog box for the channel. Area two of Figure T contains a column that lists the Status of the channel tares. This information follows the graphical status indication shown in column one. It will also show graphics that indicate if the channel is overloaded. If the channel is reading its full scale input it is known as overloaded, and the graphic will be shown. Area three of Figure T shows the current Engineering Unit (EU) values for channels listed in the Tare Removal Dialog Box. The EU values are arrived at using the engineering unit conversion equation or lookup table for the channels. Area four of Figure T shows the engineering unit conversion equation offset coefficient and the channel s engineering unit tag. This value will change as the result of performing a tare. Area five of Figure T contains a status box that lets the user quickly see the tare status for the channels that are part of the test. This is useful in the case that the user has more channels in the test than will fit into one screen of the spreadsheet. If the user s test has more channels in it than can be shown in the spread sheet control a vertical scroll bar will appear that allows the user to scroll down to the other channels. The status area is merely a convenient feature. Area six of Figure T contains a button that instructs PI660 to perform a tare on the selected (highlighted) channels. When PI660 performs a tare it samples each channel that is highlighted, converts the mvrti measurements to EU using the EU conversion equations for the channels, determines new EU conversion equation offset coefficients for the channels, and checks the channels for overload conditions. The new EU conversion equation offset coefficients for the channels should make the channels read the EU value shown in area seven of Figure T. 84

85 Area eight of Figure T contains buttons that help the user highlight channels without having to use the Windows extended select (control, shift, click) mouse operations. The buttons allow the user to select channels not showing the graphic (Select Bad), all channels (Select All), and channels that are part of the seamless backup system s channels (Select Backups). Operations performed in the Tare Removal dialog box are performed on selected (highlighted) channels only. It is important to note that not all channels will be listed in the Tare Removal Dialog box. Thermocouple channels use internal NIST traceable lookup tables and are therefore not Tareable. Lookup table channels do not use the engineering unit conversion equation, and thus are not listed either. EU Calibration Coefficient Calculator The EU Calibration Coefficient Calculator is a convenient tool that allows the user to enter transducer information from a transducer data sheet as the basis for calculation of the slope and offset coefficients for the EU conversion equation. From time to time the user will have a transducer that is well calibrated and that is delivered to him with a data sheet that contains information about the transducer s mv outputs for a set of EU conditions that the transducer may measure. The user can enter two of these point pairs into the EU Calibration Coefficient Calculator and have PI660 calculate the EU conversion equation from that data. Figure U shows the EU Calibration Coefficient Calculator dialog box Figure U. EU Calibration Coefficient Calculator Area one of Figure U contains two edit controls wherein the user enters two Engineering Unit (EU) values from the transducer data sheet for the channel. The values, known as step 1 and step 2 are used with the equivalent values shown in area two of Figure U. In Figure U the user has equated 100 EU to 220 mv (Step 1) and 0.0 EU to 10 mv. The equivalent values, shown in area two, are either in mv output of the gage or Ohmic value of the gage. Area three of Figure U shows two non-changeable controls that indicate if the equivalent values in area two mean mv or Ohms. PI660 determines this based on the style of excitation the user has chosen for the transducer. If the user is using constant current excitation then the equivalents are listed as Ohms. If the user is using constant voltage excitation then the equivalents are listed as mv. In either case, the equivalents have to do with the gage. Area four of Figure U contains an area that shows the excitation type and level that the user has selected for the channel. The user can not change settings with these controls. They are for information purposes only. Area five of Figure U contains two text controls that show the proposed offset and slope coefficients for the channel. The coefficients are calculated by forming a straight line fit between the point defined by (Step 1 EU, Step 1 Equivalent) and the point defined by (Step 2 EU, Step 2 Equivalent). Area five also demonstrates that the offset coefficient of the PI660 EU conversion equation is defined in EU (In the example of Figure U the units for the channel are PSI), and that the slope coefficient of the EU conversion equation is defined as EU per mvrti. In the Figure the units for the channel are PSI. 85

86 Area six of Figure U contains a button (Use) that when pressed will cause the coefficients of the proposed equation (area five of Figure U) to be used as the EU conversion equation coefficients for the channel. If the user clicks the use button then the squared and cubed coefficients of the EU conversion equation for the channel will be equated to zero. Performing Automatic Zero Automatic zero is the process by which a channel removes any amplifier offset that is due to instrumentation amplifier drift. It is performed in one of three ways. First, when the user downloads a channel s settings the channel will perform an automatic zero if it has its automatic zero circuit enabled. The user enables or disables the circuit in the Channel Definition dialog box. Second, a selective automatic zero can be performed using the Selective Automatic Zero dialog box. Third, all channels that are part of the current test configuration can be instructed to perform an automatic zero. Figure V shows the selective automatic zero dialog box. It contains a listing of the test channels that have automatic zero enabled Figure V. Selective Automatic Zero Dialog Box Area one of Figure V contains a list control showing the channels in the test that have automatic zero enabled. The user enables automatic zero for a channel using the Define Channel dialog box. Area two of Figure V contains a listing of the channel s from area one that the user desires to perform an automatic zero on. The user moves channels into area two s list control by using the buttons shown in area three of Figure V. When the user has all the channels that he wants to zero represented in the area two list control he merely clicks the button in area four of Figure V (Zero) to begin the automatic zero process. When the user clicks the Zero button PI660 tells the 6000 system to select the appropriate channels and then instructs the channels to perform automatic zero operations. At the end of the automatic zero operation PI660 reads the zero values for the channels by sampling the channels and averaging the resulting data arrays for each channel. The mean value of the data collected becomes the Voltage Conversion equation offset coefficient. PI660 performs the same hardware based automatic zero no matter which method of automatic zero the user employs. The offset coefficient of the Voltage Conversion equation is changed due to an automatic zero. The user can perform automatic zero on all test channels (without selecting them with the Selective Automatic Zero Dialog Box) by clicking the menu item Test/Zeroing/Auto Zero All Channels menu selection. Performing Zero Plug Calibrations Zero plug calibrations allow PI660 to characterize differences between a channel s card edge zero input (when the channel has its +/- leads shorted together at the card edge using a zero plug) measurement and its automatic zero (when the channel has its +/- leads shorted together automatically on board at the entrance to the input selection switch) measurement. This process is only done for users that want to try to make measurements that are better than the 86

87 specified accuracies of their channels, or by users that want to account for line losses due to extremely bad wiring situations. Figure W shows the zero plug calibration dialog box. Figure W. Zero Plug Calibration Utility The zero plug calibration utility requires that all channels on a card have a shorting plug installed as the input to the channels. The utility is quite rudimentary. The Begin button in area two of Figure W instructs PI660 to perform a zero plug calibration on all channels on the card selected in the card selection control shown in area one of Figure W. Zero plug calibrations can take 15 or so seconds per card. When PI660 performs a zero plug calibration it Performs an automatic zero Reads the automatic zero residual offset Reads the zero plug offset Calculates the difference between the automatic zero offset and the zero plug offset Stores the difference in the channel EEPROM Sums the automatic zero offset and the zero plug offset and uses that as the offset portion of The Voltage Conversion Equation Summary of Calibration Voltage Calibration is a process in which an equation is generated that maps voltage measured by 6000 system analog channels into voltage traceable to a voltage source that a NIST laboratory has calibrated. Engineering unit calibration is a process in which an equation is generated that maps traceable voltages to engineering unit quantities. Both equations can be ignored, entered by the user, or generated by PI660. PI660 contains a number of different calibration tools and possibilities. The user must carefully match the calibration requirements for his transducers with the tools required to properly use the transducers. Not all users will use all calibration tools in PI660. Further, not all transducer types will require calibration. 87