Data Sheet. RS Datascan data acquisition system

Transcription

1 Data Pack D Issued March Data Sheet RS Datascan data acquisition system Introduction The RS Datascan range of distributed data acquisition modules provides a flexible, easy to use, cost effective means of connecting transducers to computers providing a simple black box solution for small monitoring applications using analogue sensors, either centrally or distributed. Historically, analogue information about temperatures, pressures etc, has been monitored on displays near to the process which need constant observation by people to ensure that a test, process or production line is running according to certain parameters. With today s desktop computers and advances in measurement technology the ability to monitor these parameters automatically and remotely on a standard computer is now a reality. RS Datascan has been designed for engineers, technicians and process supervisors who need to log temperature, pressure, flow, stress and movement on a personal computer in applications such as industrial monitoring, process monitoring, test and research laboratories, production test, colleges and universities. Being an all-in-one black box, RS Datascan overcomes disadvantages of PC card based systems, providing software configurable inputs, on board processor, C computer interface and module to module network interconnection, all within the rugged DIN rail mounted body. It allows the user to concentrate on the external applications, the sensors needed and on the information generated and not on, for example, hardware configuration, internal address setting and difficult external cable terminations. 1.0 What is Datascan? 2.0 How to choose Datascan 3.0 Datascan overview 3.1 Analogue to digital converter 3.2 Microprocessor-RAM 3.3 local interface 3.4 RS-485 network 3.5 Packaging Figure 1 Datascan block diagram 4.0 Datascan specification 4.1 Ranges Resolution Accuracy 4.2 Speed 4.3 interface 4.4 RS-485 network 4.5 Power requirements 4.6 Battery back-up Figure 2 Single module configuration diagram Figure 3 Multi module configuration diagram 5.0 Recorder software 5.1 Overview 5.2 Configuration 5.3 Scanning to screen 5.4 Logging to disk 5.5 Other requirements 6.0 Datascan software features 6.1 Local monitor displays Figure 4 Overview Figure 5 Sample monitor display 6.2 Automatic reporting to printer/modem Figure 6 Time and triggered reporting Part no. RS stock no RS 8 channel RS 16 channel

2 1.0 What is Datascan? RS Datascan is an intelligent measurement and data collection unit developed for factory, industrial and scientific data acquisition applications. RS Datascan provides new concepts and standards in interfacing sensors to computers. Based on years of practical experience, the product has been carefully designed to take the chore out of connecting distributed plant sensors to a range of standard computers by providing a comprehensive selection of user features and facilities. The concept of Datascan is to provide the user with a distributed real time data that can be easily and cost effectively configured, installed and expanded. A Datascan 7200 system is able to monitor the following: dc voltage Temperature (thermocouples or PRT) Resistance Strain gauges (full, half or quarter bridge configuration) In addition, the powerful, programmable conversion software supplied with RS Datascan allows the user to tailor the system to suit specific transducer requirements. Simple control commands together with several reporting modes and formats, tackle the often inherent problems of interfacing to existing software packages. 2.0 How to choose Datascan The RS Datascan range consists of two modules each supplied with a simple software package to allow the user to configure and monitor information on a standard PC using Windows 3. See Section 5 for a description of the software. The 7220-RS (RS stock no ), consists of 16 analogue input channels, each individually configurable to the following signals: dc voltage, 4-20mA (with shunt), thermocouples The 7221-RS (RS stock no ), consists of 8 analogue input channels each individually configurable to the following signals: dc voltage 4-20mA (with shunt) thermocouples, PT100, strain gauges. The module should be selected according to the types of signals to be connected. Both modules can be connected on the same network and offer the same software facilities. (Section 4 for detailed specification of both modules). 3.0 Datascan overview 3.1 Analogue to digital converter The A/D converter can be programmed to provide either 16 bits or 14 bits of resolution. At 16 bits the unit can make up to 40 readings/sec with high rejection to common or series mode mains-borne noise. At 14 bits the unit can perform at 400 readings/sec with reduced noise rejection. Each channel is software selectable to either 16 bits or 14 bits via the software provided. 3.2 Microprocessor RAM The on board CMOS processor controls the scanning, the network and the interface. It can calculate engineering units and check for high and low alarm conditions. Battery supported memory enables all system configuration data to be held in a non volatile form making programming a one-off task. The measurement processors have more than 50 resident software commands ensuring information is presented to the host in engineering units, and reducing the processing load on the host. Programming facilities include: Linear calibration of channels Polynomials for non-linear calibration of channels Square root and reciprocal functions Software filtering of measured data Alarm limit checking Linearisation of thermocouples I/O definition of each channel. 3.3 local interface The isolated serial port enables the user to communicate with the module using a standard computer or VDU. The baud rate is switch selectable providing the following rates: 300 baud, 1200 baud, 9600 baud, baud as standard. Datascan can be connected to any computer utilising such as IBM PC, VAX, Macintosh etc, or to programmable controllers as a distributed analogue data acquisition system. 3.4 RS-485 isolated communication network One of the unique features of the RS Datascan is its distributed networking capability. Each measurement module can be used stand alone with a host computer or terminal, or as part of a network cluster of up to 32 modules. The token passing network can extend over a distance of 1.2km (4000ft) and support up to 1000 channels of various types. The bandwidth allows the status of these 1000 channels to be updated every second. Each measurement module has access to the data in every other measurement module in the network, providing the feature of real time global data. The network continuously broadcasts all the measured data globally. At any point a host computer or terminal can connect to the measurement module user port and access part or all of the measured data on the network. Using the modules the maximum channel capacity is 256. The network is self-configuring permitting units to be switched on or off with minimal disturbance to data transmission. All communications on the network are packet orientated. Status bytes within the packet indicate the message, designation and source, the message type and the number of bytes of information. Message integrity is assured using a checksum verification byte. The network can support dual token operation. This permits channels to be scanned at a higher frequency on one ring than the other, permitting high speed scanning and reporting for any critical channels on the system. 2

3 3.5 Construction Great attention has been paid to the packaging, installation and operation of the unit in harsh environments. Extensive use of CMOS surface mounting technology enables this unit to be packaged into a compact rugged DIN rail carrier making it easy to install close to the measurement point in most confined areas. With features such as high noise rejection, wide temperature range (-10 to +60) and network distribution, RS Datascan can be located in plant areas which are normally restricted for sensitive electronic equipment offering the associated benefits of measurement integrity and significant reduction in cabling and installation costs. A block diagram is shown below. Figure 1 Datascan block diagram 8 or 16 analogue inputs, dc, 4-20mA thermocouple, strain, PT100 To host computer or local display terminals 14/16 bit A/D converter Microprocessor with battery backed up memory Interface Power supply Isolated RS-485 network interface To other 720 RS modules (max 32 ) 4.0 Datascan specification 4.1 Range, resolution, accuracy Accuracy Sensor Sensitivity (includes junction type Ranges 16 bit 14 bit error) dc 10V 320µV 1.28µV ±0.02% rdg % voltages range + 1 bit (7220/21) 1.3V 40µV 160µV ±0.02% rdg % range + 1 bit 150mV 5µV 20µV ±0.02% rdg % range + 1 bit 20mV 0.625µV 2.5µV 16 bit (±0.02% rdg % range + 5µV) 14 bit (±0.02% rdg % range + 10µV) Thermocouples (7220/21) K type 100 to to to J type 50 to to T type 150 to R type 0 to S type 0 to E type 50 to to B type 200 to N type 200 to to to PRTs 7221 only PT to (4 wire) 50 to Strain gauges 7221 only Full bridge 0-10,000µE 0.62µE 3µE 10µE Current 4 to 20mA 4 to 20mA.01µA.08µA ±0.15% dc common mode interference error <50µV/V on 1.3V and 10V ranges. <5µV/V on 20mV and 150mV ranges ac common mode interference error <1µV/V (50 or 60Hz) ac series mode interference error <1mV/V for line frequencies within 0.05% of nominal (50 or 60Hz) Overload protection ±30V continuous on one channel ±200V transients of 0.1s duration occurring less than 1/min. All accuracies are for temp coeff <30ppm/ +0.2µV/ Power consumption Dimensions Weight Environmental 7220 <2 Watt at 24V Width 230mm 750gm Operating temp RH Height 123mm 10 to % non- Depth 80mm Storage temp condensing 7221 <2 Watt at 24V 20 to +80 3

4 4.2 Measurement speed (individual channel speed selection) 16 bit 40 readings/second 14 bit 400 readings/second 4.3 interface baud rates: 300, 1.2K, 9.6K and 38.4K (switch selectable) 10m maximum to host Local display pages 10 System performance Single 72xx 300 analogue results/sec Network with 4 72xx 600 analogue results/sec 4.4 Network Electrical specification RS-485 Transmission 93.75Kbaud Data rate 1000 results/sec Total channels per network 256 Maximum number of nodes 32 Maximum length 1.2km (4000ft) Recommended cable Belden 9207 (up to 1.2km) types Belden 8761 (up to 300m) 4.5 Power requirements 24Vac or 500mA 4.6 Battery Back-up life Battery type 5 years unpowered Lithium Figure 2 Minimum configuration requirements without expandability Combination module Host computer }Scanning (8/16 Channels) Figure 3 Building block method: multi-module configuration Secondary computer or display terminal Host computer Module RS-485 network Module }Scanning (8/16 Channels) }Scanning (8/16 Channels) 4

5 5.0 Recorder software 5.1 Overview Each RS Datascan module comes complete with a Windows 3.0 based software package called RS Recorder. Recorder breaks down into two main sections enabling the user to configure each Datascan module and Record data to disk for later analysis by using industry standard analysis packages such as Lotus 123 and Excel. The package is designed to be easy to use utilising the standard Windows environment and should enable the user to quickly set up and run a simple monitoring system. 5.2 Configuration The configuration utility allows the user to create, modify and save multiple Datascan set ups which relate to specific experiments or processes. A maximum of 64 channels can be configured to different channel types on both the 7200 series modules ie and Selectable options include Range, Resolution, Channel Description and Alarm Checking. Channel setups can be copies allowing rapid configuration of similar inputs. Scanning speed is selectable from 1 second to 32,000 seconds or approximately 8 hours. 5.3 Scanning to screen Using Recorder the user can load a previously created configuration and monitor the selected channels to a standard screen layout at the user defined scanning rate. Channel value, description, units as well as alarms that are occurring are displayed in real time. 6.0 Datascan software features In addition to the standard data acquisition facilities which are brought out in standard software packages such as configuration monitoring and alarming RS Datascan has a whole selection of advanced facilities that can be configured by the user of simple ASCII commands. These include the following: Local monitor displays Automatic reporting to printer/modem Software driven clock Communications watchdog Square root polynomial and filter functions Alarm hysteresis Autonomous output support Channel shadowing. Refer to RS Datascan manual for a full listing and detail of use. However, below follows a brief introduction to two very useful advanced facilities. Local monitor displays Automatic reporting to printer/modem. 6.1 Local monitor displays Each RS Datascan module has an on board port for connecting to a host computer or dumb terminal display. Datascan supports multiple host connection which utilising the networking facilities can provide local and remote displays for operators or for use when commissioning or fault finding. Figure 4 gives an overview. Figure 4 PC Local display Printer 5.4 Logging to disk Using Recorder the data can be logged to a disk based file as well as being displayed on screen. The data is saved in CSV (Comma Separated Values) for easy import into standard analysis packages. The use of Windows facilities allows the user to collect data through Recorder while utilising other software packages for analysis of data previously collected Other features Recorder has full on line help on all aspects of its operation. Two standard configurations are provided with simple default settings to enable the user to easily install and collect data from the module. Standard macros are also supplied which enable data to be imported into formats suitable for both Lotus 123 and Excel. 5

6 Each RS Datascan module can be configured to display up to 10 pages of monitoring display to either a TV925, VT52 or VT100 type terminal or a terminal emulation package on a PC or other host computer. Each page can display channels located on a RS Datascan network and can be used to group channels in meaningful combinations. Channel number units and value are displayed together with alarm and error conditions as well as titles per page and a global message. Once a monitor is running displayed pages are changed by a single key action (0.9 for displays 0.9). Figure 5 shows a sample monitor display. See RS Datascan manual for further details. Figure 5 Sample monitor display 09:46:48 A GLOBAL MESSAGE Boiler Monitor OVERIDEMANUAL INTERLOK AUTO Riser Riser Riser Ambient Top L Top Lower Lower Lower Power Power Power Speed Speed bar bar bar MW MW MW rpm rpm A AL AH 6.2 Automatic reporting to printer/modem It is possible to set up RS Datascan to output a set of measurements at a defined time, interval or when an alarm condition is detected. This facility can be used with a modem or local printer () to provide a simple alarm monitoring, or logging function independent of the host computer. A software clock can be set up to label reports with the time of day Note: Clocks are not linked and are accurate to within 20 seconds per day.) This facility can be programmed remotely from the host or through a dumb terminal or terminal emulation package. Figure 6 gives an example format. See RS Datascan manual for further detail. Figure 6 Time and triggered reporting $ $ $ BOILER R MONITOR 09:12: L L H Monitor page: 40 colomn mode The information provided in RS technical literature is believed to be accurate and reliable; however, RS Components assumes no responsibility for inaccuracies or omissions, or for the use of this information, and all use of such information shall be entirely at the user s own risk. No responsibility is assumed by RS Components for any infringements of patents or other rights of third parties which may result from its use. Specifications shown in RS Components technical literature are subject to change without notice. RS Components, PO Box 99, Corby, Northants, NN17 9RS Telephone: An Electrocomponents Company RS Components 1997