^3 MLDT Interface Board. ^4 3Ax xUxx. ^5 October 15, 2003

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1 ^1 USER MANUAL ^2 Accessory 29 ^3 MLDT Interface Board ^4 3Ax xUxx ^5 October 15, 2003 Single Source Machine Control Power // Flexibility // Ease of Use Lassen Street Chatsworth, CA // Tel. (818) Fax. (818) //

2 Copyright Information 2003 Delta Tau Data Systems, Inc. All rights reserved. This document is furnished for the customers of Delta Tau Data Systems, Inc. Other uses are unauthorized without written permission of Delta Tau Data Systems, Inc. Information contained in this manual may be updated from time-to-time due to product improvements, etc., and may not conform in every respect to former issues. To report errors or inconsistencies, call or Delta Tau Data Systems, Inc. Technical Support Phone: (818) Fax: (818) Website: Operating Conditions All Delta Tau Data Systems, Inc. motion controller products, accessories, and amplifiers contain static sensitive components that can be damaged by incorrect handling. When installing or handling Delta Tau Data Systems, Inc. products, avoid contact with highly insulated materials. Only qualified personnel should be allowed to handle this equipment. In the case of industrial applications, we expect our products to be protected from hazardous or conductive materials and/or environments that could cause harm to the controller by damaging components or causing electrical shorts. When our products are used in an industrial environment, install them into an industrial electrical cabinet or industrial PC to protect them from excessive or corrosive moisture, abnormal ambient temperatures, and conductive materials. If Delta Tau Data Systems, Inc. products are directly exposed to hazardous or conductive materials and/or environments, we cannot guarantee their operation.

3 Table of Contents INTRODUCTION...1 Connectors...1 P1...1 J1...1 J2...1 J3...1 J4...2 J5...2 J6 (JS3)...2 J7 (JS4)...2 J8...2 TB1...2 MLDT OPERATIONAL PRINCIPLE...3 Linearity...4 Resolution...4 Range...5 Circulation...5 Update Time...5 ACC-29 to MLDT Connections...6 ACC-29 Compatible MLDT Timing...6 PMAC Parameter Setup...8 Timer (1/T Counter Capture) Register Addresses for ACC Encoder Decode I-variable Setup (I940-I975)...10 Servo Cycle Extension...10 User Unit Definition...11 Nonlinerality Compensation...11 CONNECTION TO ACC Incremental Encoder Input...13 DSPGATE General Purpose Outputs...13 Incompatibility with ACC-24P/V...13 An Example of Parameter Setup...13 Servo Cycle Extension Setup...13 Encoder Conversion Table Setup...14 Timing Considerations...14 A List of Tested MLDT Devices...14 CONNECTOR PINOUTS...19 J2 (10 Pin Header)...19 J3 (10 Pin Header)...19 J4 (34 Pin Header)...20 J5 (34 Pin Header)...21 J6 (16 Pin Header)...22 J7 (16 Pin Header)...22 J8 (37 Pin DB Connector) 1,2, TB1 (4 Pin Terminal Block)...24 ACC-29 E-POINT JUMPER DESCRIPTIONS...25 Interrogation Pulse Echo Enable...25 Incremental Encoder Interface...26 LDT Single-Ended/ Differential...27 J2 Output Supply Voltage Configuration...27 J3 Output Supply Voltage Configuration...28 Interrogation Pulse Width...28 Table of Contents i

4 Servo Clock Extension for Channels 1 to Servo Clock Extension for Channels 5 to DCLK Divide Jumpers 1, Power Supply Jumpers...30 ii Table of Contents

5 INTRODUCTION PMAC s Accessory 29 (ACC-29) is a standalone printed circuit board which is designed to interface with up to eight channels of Magnetorestrictive Linear Displacement Transducers (MLDTs). ACC-29 can be used in conjunction with both the PMAC-PC and the PMAC-VME. It communicates to PMAC via its J1 connector. This connector should be linked to PMAC CPU board s J2 (JEXP) connector via the supplied 50-pin flat cable. Since PMAC-STD does not have a JEXP connector on its CPU board, it is not compatible with ACC-29. The ACC-29 board is designed as a 1/2-size PC extension board. However, it uses the PC bus only for digital power supply (+5V). In standalone operations, or for use in conjunction with PMAC-VME, a terminal block is provided for power supply connections. The basic ACC-29 interface board can handle a maximum of four channels of MLDT inputs through one on-board DSPGATE. ACC-29 with Option 1 extends the board's capability to eight channels by adding a second on-board DSPGATE. This manual is intended to provide the relevant information for the use of ACC-29 in conjunction with PMAC. The PMAC and the transducer connections to ACC-29 will be explained. In addition, the required changes to the relevant I-variables of PMAC, and the modifications to its default Encoder Conversion Table entries will be pointed out. We start by describing the connectors on the ACC-29 interface board. This is followed by a brief description of the operation principle of the categories of MLDTs which are compatible with ACC-29. ACC-29 to MLDT connections, compatible timing sequences, and the required PMAC parameter modifications will be described next. ACC-29 s complete connectors and jumpers definition lists are provided at the end of this manual. Connectors Please refer to the schematic layout diagram of ACC-29 for the connectors' locations on the board. This is shown in Figure 1. Also, refer to the connectors pin definition listings at the end of this manual. P1 This connector provides structural support as well as the power supply (+5V) for digital side of the onboard opto-isolation circuits. It is also possible to bring in the +12V and +5V power supplies required for the transducer side of the on-board opto-isolation circuits through P1. To do this, jumpers E32 and E33 must be installed Note: The installation of these jumpers voids the opto-isolation feature of ACC-29. J1 This connector provides the link between ACC-29 and PMAC via the J2 (JEXP) connector on the CPU board. A 50-pin flat cable is provided for this task (see Figure 2, the connection diagram). J1 must be connected to the PMAC CPU board's J2 (JEXP). J2 This connector brings out the four Compare-Equal signals (EQU9 to EQU12) and the four generalpurpose output signals (OUT9 to OUT 12) associated with the first DSPGATE on ACC-29. Jumpers E18 and E19 determine the signals polarities. For MLDT interfacing this connector is not required. J3 This connector brings out the four Compare-Equal signals (EQU13 to EQU16) and the four generalpurpose output signals (OUT13 to OUT16) associated with the second DSPGATE on ACC-29. Jumpers E21 and E22 determine the signals polarities. For MLDT interfacing this connector is not required. (This connector is only available on ACC-29 with Opt. 1). Introduction 1

6 J4 This connector brings in all the encoder channels and the home flags associated with the first DSPGATE on ACC-29. For MLDT interfacing this connector is not required. J5 This connector brings in all the encoder channels and the home flags associated with the second DSPGATE on ACC-29. For MLDT interfacing this connector is not required. (This connector is only available on ACC-29 with Opt. 1). J6 (JS3) This connector contains miscellaneous I/O signals related to the first DSPGATE on ACC-29. It is typically used for direct connection to an ACC-28 (the four channel analog-to-digital converter board). For MLDT interfacing this connector is not required. J7 (JS4) This connector contains the miscellaneous I/O signals related to the second DSPGATE on ACC-29. It is typically used for direct connection to an ACC-28 (the four channel analog-to-digital converter board). For MLDT interfacing this connector is not required. (This connector is only available on ACC-29 with Opt. 1) J8 This is a 37-pin DB connector used for interfacing with up to 8 channels of MLDTs. In addition, in order to take full advantage from the opto-isolation feature of the board, the +5V and the +12V (to +15V) power supplies for the transducer side of the board should be brought in through this connector. TB1 This is a 4-pin terminal block which provides an alternative power supply input for standalone applications outside the PC bus. The +5V power supply input is intended for digital side of the on-board opto-isolation circuits. However, it is possible to bring in the +12V and +5V power supplies for the circuits on the MLDT side of the opto-isolation through TB1. To do this, jumpers E32 and E33 must be installed. Note: The installation of these jumpers voids the opto-isolation feature of ACC Introduction

7 MLDT OPERATIONAL PRINCIPLE For a detailed discussion of a particular MLDT device the reader should refer to its manufacturer's manual. In addition, the article by J. Smith and S. Deiters in the Nov./Dec issue of Motion Control provides a general discussion of these transducers and their motion control applications. For the users convenience, a brief discussion of MLDT operational principle will follow here. Figure 1 on the following page shows the essential elements of a typical MLDT. It consists of three basic elements: the processing head, the waveguide, and the magnetic ring. The cylindrical waveguide, which is attached to the processing head, has a ferromagnetic (typically steel) outer shell. Inside this shell, a conducting wire runs longitudinally. The magnetic ring is typically attached to the moving part whose relative displacement with respect to the processing head is to be measured. A magnetostrictive transducer provides (indirectly) position information based upon the travel time of a strain pulse between two points on a conducting medium (the waveguide's outer shell). This pulse, which is propagated at ultrasonic velocity (typically around 9.01 to 9.3 ms/in.), is generated underneath the magnetic ring whenever an "interrogation pulse" is transmitted from the processing head via the conducting wire. This strain pulse (also known as the "return pulse"), is then detected in the receiver circuit of the processing head. Since the velocity is a material constant for a given waveguide, the travel time is directly proportional to the instantaneous distance between the processing head and the traveling magnetic ring. When used with PMAC through an ACC-29, this travel time is measured by one of the timer registers (1/T binary counters) within its DSPGATEs. For each MLDT device one period counter is required. First, at the beginning of each servo cycle, the interrogation pulse is generated on ACC-29. This pulse is transmitted to the processing head via the appropriate pins of the J8 connector. Either the interrogation pulse, or its echo (jumper selectable), would initiate the counting process of the designated counter. The counting continues until the strain pulse is returned from MLDT device via the same connector. The strain pulse stops the counting and latches the counter's value for a PMAC read. This value is a direct measure of the relative displacement between the magnetic ring and the processing head. MLDT Operational Principle 3

8 Processing Head Wire Guide Conducting Wire Magnetic Ring Traveling Marker Power supply, Interrogation, and Return (strain) pulse signals Typical Timing: Interrogation Pulse (from ACC-29) (Typ. 1 ms) Echo Time (measure of distance) Return Pulse (to ACC-29) (Typ. 1 m s) Figure 1: Typical Elements and Timing for a MLDT device Linearity Typical deviations from linearity are quoted as 0.05%. However, it is possible to compensate for such nonlinearities using look up tables (e.g. PMAC's Leadscrew Compensation Table). Some of the MLDT manufacturers provide a linearity compensation table which can be used in conjunction with the PMAC s Leadscrew Compensation feature (see the section on "Nonlinearity Comp."). Resolution The positional resolution (minimum increment of stroke that can be detected) of an MLDT transducer is directly proportional to the resolution of time measurement between the initial interrogation pulse and the echoed strain pulse. Typically, a digital counter is used to measure this travel time (e.g. DSPGATE's timers for the case of ACC-29). The higher, the counter clock frequency, the higher the resolution, or the smaller the minimum detectable incremental motion. In general, the resolution is given by the following formula. Resolution = 1/ (G x F) Where F is the clock frequency, and G is the manufacturer supplied transducer gradient (typically 9.05 µs/in. or µs/mm). For example, the DSPGATE 1/T counters used in ACC-29 run at MHz. Hence, ACC-29 Resolution=(9.05 x ) -1 = inches. Note that this resolution will vary slightly with different makes of MLDTs due to slight changes in their given G values. Note that a 50 MHz version of ACC-29 may be special ordered direct from factory. With this version, the resolution improves to inches. 4 MLDT Operational Principle

9 Range The range of measurable displacement is directly proportional to the counter size (its number of bits). For example, the effective size of the timers within the DSPGATES is 23 bits. Thus, for the above example the ACC-29 displacement range will be ACC-29 Range = ( x 2 23 ) = 31,457 inches Circulation Circulation or recirculation is a digital process that improves the resolution of an MLDT by (artificially) increasing its gradient G. This provides more counting time for the counter, improving resolution. The process involves retriggering an interrogation pulse, a fixed number of times, by the return pulse. Required Circulation # = Int.[1/(G x F x DR)] Where DR is the Desired Resolution, and Int.[x] means x s integer value when rounded up to the next higher number. Thus for the above example, in order to increase the resolution to (better than) in., the number of circulation required is given Required Circulation # = int. [(9.05 x x 0.001) -1 ] = int.[3.747]= 4 Note that the "Update Time" will now be increased to 36.2 (9.05 x 4) ms/in. This delay may become unacceptable for longer ranges of motion. As a result, circulation is not recommended for high performance servo applications. The best way to improve resolution is to increase the clock frequency F. Note that ACC-29 does not support Circulation due to its adverse effects on the servo performance. However, some MLDT processing heads contain electronics that carry out circulation internally. This leads to larger manufacturer specified equivalent G values and improved resolution. As far as ACC-29 is concerned, still one return pulse is expected per each interrogation pulse. Update Time For a given counter clock frequency, and a fixed transducer gradient, the Update Time is proportional to the stroke length (relative distance between the traveling magnetic ring and the processing head). Update Time= S x G x Circulation where S is the stroke length. Note that for ACC-29, since Circulation is not supported, Update Time reduces to: ACC-29 Update Time= S x G For example, the update time to measure 100 inches of relative distance is given by: ACC-29 Update Time (for 100 in.) =100 x 9.05 = 905 ms Note that this period is more than twice the default PMAC servo cycle which is approximately 442 ms. The servo cycle clock is used on the ACC-29 board for generation of the interrogation pulse. To handle long strokes with ACC-29 and because only one interrogation pulse can be generated per servo cycle, ACC-29 is equipped with jumpers which can divide down the servo clock for the purpose of interrogation pulse generation. These jumpers (E25 and E26) can divide the servo clock by 2, 4, 8, 32, 64, 128, or 256 (see the jumper definition section at the end of this manual). For instance, to handle 100 in., the servo clock should be divided by 4 (E25C or E26C should be installed). Also, note that for this particular channel, PMAC s Ix60 (the servo cycle extension parameter) should be modified accordingly. In this particular case, the appropriate Ix60 should be set to 3 (see PMAC s User Manual under the section on I- variable Specification and the section on "Servo Cycle Extension" later in this Manual). It is important to realize that reducing the servo loop closure frequency can adversely affect the closed loop performance for an otherwise unchanged set of gains. Thus if, due to long stroke lengths, servo cycle period extension is required, all the servo gains (especially the derivative gain Ix31) would often MLDT Operational Principle 5

10 have to be reduced. Still, the servo performance is very likely to be negatively impacted, especially if the servo loop was originally tuned for a very fast closed loop response. ACC-29 to MLDT Connections All the connections between the ACC-29 and MLDT processing heads are through the 37-pin DB connector J8 (please refer to the pin description lists at the end of this manual). Up to four MLDT devices may be interfaced with the basic ACC-29. With its Opt.1, ACC-29 can handle a maximum of eight MLDTs. Each MLDT s interface consists of two signals LDTOx (x=1 to 8) and LDTIx. LDTOx is the interrogation pulse sent from ACC-29 to the MLDT processing head. LDTIx is the return (strain) pulse sent back to ACC-29 from the processing head. ACC-29's default jumper setting accepts LDTIx signals as single-ended inputs. When used as differential inputs, the matching LDTIx/ should also be connected for each channel. Jumpers E9 through E16 determine the type of input signals for channels 1 through 8 respectively. LDTOx and LDTOx/signals are also and differential. However, if single-ended interrogation pulse is required, either LDTOx or LDTOx/ may be connected. The signal, which is not used, must be left floating. Both of these signals are TTL level type. The maximum allowable voltage level on the input signals LDTIx and LDTIx/ should not exceed +15V with respect to the GND signal. J8 also brings in the power supply (+12V to +15V) for the transducer side of the opto-isolation circuity on ACC-29. To take full advantage of this feature, the power supply connectors on J8 should be connected to a separate power supply from that used for the "digital" side of the opto-isolation circuitry. This "digital" power supply is brought in through either P1 or TB1. It is possible to use the digital power supply for the transducer side of the opto-isolators by installing jumpers E32 and E33. However, this would defeat the opto-isolation feature of the board and should not be done if an unacceptable level of electrical noise is suspected to be present. ACC-29 Compatible MLDT Timing Figure 4 shows the three types of MLDT timing sequences which are compatible with ACC-29 s DSPGATE counting operations. As mentioned above, each of the four 1/T counters within each DSPGATE measures the time between the interrogation pulse and the return pulse for a single channel of MLDT interface. 6 MLDT Operational Principle

11 ACC-29 TRANSMIT RS422 4 ms LDTOX LDTOX/ TYPE A ACC-29 RECEIVE RS422 LDTIX 0.1 ms(min.) LDTIX/ ACC-29 TRANSMIT RS422 1 ms LDTOX LDTOX/ TYPE B ACC-29 RECEIVE RS422 LDTIX 0.1 ms(min.) LDTIX/ ACC-29 TRANSMIT RS422 1 ms LDTOX LDTOX/ TYPE C ACC-29 RECEIVE RS422 LDTIX LDTIX/ Figure 4: ACC-29 Compatible MLDT Timing Diagrams MLDT Operational Principle 7

12 For type A (e.g. Magnetek Quick-Stik transducer), the interrogation pulse width must be 4 ms. This is achieved by removing jumper E23 for the first DSPGATE (channels 1 to 4), or removing jumper E24 for the second DSPGATE (channels 5 to 8). In addition, since the interrogation pulse is not immediately echoed back from the processing head, the corresponding channel's jumper ExA must be installed. Here x refers to the channel number (from 1 to 8). In addition, the corresponding channel's Encoder Decode I- variable (I940 to I975) should be set for pulse and direction. More about I-variable settings will be said in the next section. For type B (e.g. Temposonics II RPM, or Balluff s MLDTs), the period of the interrogation pulse is 1 ms. Thus the default (installed) values of E23 or E24 must be used. In addition, Jumpers ExA need not be installed, however, if installed, the counting will still work. As with the type A timing, the corresponding Encoder Decode I-variable should be set to "pulse and direction". For type C (e.g. Norstat s model GYRG), the interrogation pulse width is 1 ms. Thus the default (installed) values of E23 or E24 should be used. In addition, since the interrogation pulse is not immediately echoed back from the processing head, the corresponding channel's jumper ExA must be installed. In addition, the corresponding channels Encoder Decode I-variable (I940 to I975) should now be set for "x4 quadrature decode". PMAC Parameter Setup PMAC's default feedback sensor decode parameters are set for incremental encoders. In this mode, PMAC reads the contents of the encoder counters within the DSPGATEs every servo cycle. It then calculates incremental distance traveled during that cycle. When using MLDTs through ACC-29, the timer registers are used instead of the encoder counters, and their contents represent absolute distance. Therefore, the default values of these sensor decode parameters must be modified. This requires changes to PMAC's Encoder Conversion Table. In addition, for longer distances, it is very likely that servo cycle extension is required (see "update time" definition above). In addition, usually the PMAC s default feedback gains need to be tuned for optimum response. Encoder Conversion Table Setup The first DSPGATE on an ACC-29 board is memory mapped to the address of the Gate Array 3. The second DSPGATE (which comes with ACC-29 Option 1) is memory mapped to the address of Gate Array 4 (see the I/O memory map in PMAC User Manual). The address map for the eight timer registers within these two DSPGATEs are given in the following table Timer (1/T Counter Capture) Register Addresses for ACC-29 (See PMAC Users Manual for detailed I/O map) Channel no. GATE no. Hex. Address Dec. Address 9 3 Y:$C Y:$C Y:$C Y:$C02C Y:$C Y:$C Y:$C Y:$C03C To set up the Encoder Conversion for ACC-29, the above timer registers contents should be treated as absolute position. This requires the use of the Parallel Position Feedback option for the conversion table setup. In addition, it is recommended that the "filter" option be used. This safeguards against spurious changes, while not delaying legitimate changes at all. For more details of the Encoder Conversion Table, refer to the PMAC User Manual under Feedback Features. 8 MLDT Operational Principle

13 As an example, suppose we wish to use four channels of MLDT feedback with no other feedback device installed. To do this, the following two-step procedure should be carried out: Step 1 - Modify the Conversion table to the following form: Address Y-word Meaning $720 $30C020 Parallel from Channel 9 $721 $07FFFF Use low 19 bits $722 $ Filter is 6 counts * $723 $30C024 Parallel from Channel 10 $724 $07FFFF Use low 19 bits $725 $ Filter is 6 counts * $726 $30C028 Parallel from Channel 11 $727 $07FFFF Use low 19 bits $728 $ Filter is 6 counts * $729 $30C02C Parallel from Channel 12 $72A $07FFFF Use low 19 bits $72B $ Filter is 6 counts * $72C $ Signifies end-of-table * The filter count size is very much application dependent (amount of noise, maximum speed etc.). The exact size of this filter should be chosen by the user by considering the maximum amount of clock counts per one servo cycle. This is of course, directly related to the maximum speed of motion being sensed. Usually numbers between 2 to 8 cover the majority of applications. These correspond to the maximum speeds of 16 in./s to 64 in./s when running ACC-29 with the MHz clock and using the default servo cycle time of 442 ms. To actually carry out the above modification, you may use the conversion table editor screen in the PMAC Executive program. If you do not wish to use this editor, you can replace the default conversion table entries with the above entries using the Write (W) command. For example for the first three word entry of the above table you would command WY:$720,$30C020,$7FFFFF,$ To verify these changes you can use the Read Hex. command (RH). The same procedure would be used to extend the Conversion table for channels 5 to 8. Note: If I9 is 2 or 3 the addresses I-variables are reported back to the host in hexadecimal form which is usually desired). Step 2 - Modify the following I-variables related to feedback addresses: Ix03, Ix04, and possibly Ix25 need to be modified. Bits 0 to 15 of Ix03 tell PMAC where to look for its position feedback for motor x in the PMAC "X" address space. For the case of an MLDT feedback via ACC-29, this should point to the "X" address of its third entry in the conversion table. This is always the case with all "Parallel Conversions with Filter". If no "homing" is desired, for the above example Ix03 should set as: I103=$722, I203=$725, I303=$728, and I403=$72B. Ix04 holds the address of position feedback device which is used for velocity feedback information by PMAC. In most MLDT applications, this is going to be the MLDT device itself. In such case, the value of Ix04 would set equal to that of the corresponding Ix03 lowest 16 bits. Thus for the above example, I104=$722, I204=$725, I304=$728, and Ix404=$72B. The lowest 16 bits of Ix25 designate the address location of PMAC inputs corresponding to limit switches, home switches, and amplifier (actuator) fault flag inputs for each motor. For MLDT use, these bits should be set to the corresponding addresses of the first or the second DSPGATE on the PMAC main board (usually the default values). This is because the limit switches etc., for each servo channel, are always directed to PMAC via its JMACH connectors. These signals are not brought into the DSPGATEs on ACC-29. Note that since MLDT devices are MLDT Operational Principle 9

14 absolute position sensors the "homing" (initialization) function is often not required. However, PMAC will allow this function anyway. To do so Bit 16 of Ix03 should be set to 1 in order to indicate that the position capture for homing should be done in software. This is because Ix25 often points to a DSPGATE channel which is within the main PMAC board. As a result, automatic hardware home capture is not possible. Thus for the above example, I103=$10722, I203=$10725, I303=$10728, and I403=$1072B. Also the user would usually want to set I14=1 in order to automatically match the axis position to the absolute sensor position whenever a motor move (jog, open loop, abort, or limit) changes the motor position without letting the axis position "know" of the change. Encoder Decode I-variable Setup (I940-I975) In the previous discussion on ACC-29 / MLDT timing, it was mentioned that the return pulse from the transducer can be either a pulse signal (types A and B), or a level change signal (type C). Both kinds are acceptable to ACC-29. However, since these signals are directed into the DSPGATEs timer registers, the gate arrays must be set up properly. These counters' normal task is to measure the period of time between two subsequent encoder pulses in the quadrature form. For MLDT devices using the type C timing pattern, the corresponding Encoder Decode I-variable should be set as x4 quadrature. For example for the first counter within the first DSPGATE on ACC-29, this setting will be I940=3 or I940=7. For the second counter this setting would be I945=3 or I945=7 and so on. For type A and type B timing patterns, the pulse and direction mode is required. For the "pulse and direction" mode, I940=0, and I945=0. Servo Cycle Extension In our previous discussion of the update time, it was mentioned that due to MLDTs physical characteristics, long displacements could cause a delay time which may exceed one PMAC servo cycle. For a typical MLDT a distance greater than 48 in. would generate a delay approximately equal to one PMAC default servo cycle (442 µs). As a result, if longer distances are to be measured the servo cycle extension I-variable Ix60 must be modified accordingly. To carry out this task the following calculation should be performed Required Servo Extension= Maximum UpdateTime/ default Servo Cycle Time Since Ix60's valid values are one less than power of two (2 n -1), the nearest valid odd integer number which allows for this extension should be chosen. For example for 350 inches of travel, we have Required Servo Extension =(350 x 9.05) / 442 = If this particular MLDT (with 9.05 gradient and 350 inches of travel) is to be used for say the channel 1 of an ACC-29, then I160=7 would be the correct setup. Note that the corresponding servo clock divide jumpers on ACC-29 should be also installed. In this case, E25D should be installed. Important Note: If using PMAC firmware version V1.14 or later, it is necessary to use motor setup variable Ix10 to get the absolute power-on position from the MLDT sensor. Ix10 specifies the register to read for absolute power-on position, and how to read the data in that register. If Ix10 is set to 0, PMAC will set the power-on position for that motor to 0, even if an absolute position device is used for the motor. Ix10 must use the raw data register for the sensor, not the processed data register in the conversion data. For the ACC-29 MLDT interface, the values of Ix10 to use are: MLDT1 Timer 9 (Y:$C020) Ix10 = $18C020 MLDT2 Timer 10 (Y:$C024) Ix10 = $18C024 MLDT3 Timer 11 (Y:$C028) Ix10 = $18C028 MLDT4 Timer 12 (Y:$C02C) Ix10 = $18C02C 10 MLDT Operational Principle

15 MLDT5 Timer 13 (Y:$C030) Ix10 = $18C030 MLDT6 Timer 14 (Y:$C034) Ix10 = $18C034 MLDT7 Timer 15 (Y:$C038) Ix10 = $18C038 MLDT8 Timer 16 (Y:$C03C) Ix10 = $18C03C The '18' in the first two hexadecimal digits specifies that this is a 24-bit register that is being read (18 hex =24 dec). The last 4 hex digits specify the Y address of the register to be read. User Unit Definition To command motion in user units, the axis definition within a coordinate system must be modified. The appropriate scaling value should be set according to a particular transducer's resolution. In addition, an offset may be added if desired. For example for a typical ACC-29 with the resolution of inches, the command #1->266.67X, specifies the axis definition in units of inches. Nonlinerality Compensation If a transducer's displacement measurement is unacceptably nonlinear with respect to the length of travel, PMAC's "leadscrew compensation" feature may be used for correction. This correction is done for the end point of each commanded move if I13=0. If I13>0, then this correction is carried out continuously every I13 milliseconds (move segmentation). The correction is computed as a number of counts linearly interpolated between two closest entries in a table created by the user using the DEFINE COMP command. For more details, refer to the Feedback Features section in the PMAC User Manual. MLDT Operational Principle 11

16 12 MLDT Operational Principle

17 CONNECTION TO ACC-28 Through connectors J6 and J7, two ACC-28s (the 4 channel analog-to -digital converters) may be interfaced to the two DSPGATEs on ACC-29 and its Opt. 1. The ADC registers within ACC-29 s DSPGATEs are memory mapped to the addresses of PMAC's DSPGATE 3 and DSPGATE 4 (see the I/O map section of the PMAC Users Manual). The required DCLK clock (used for ACC-28 analog conversion) is generated on ACC-29 by dividing down the MHz clock. Jumpers E27A to E27E determine the divide down ratio. This clock frequency should be set according to ACC-28's maximum allowable clock input specification (typically less than 2 MHz). Incremental Encoder Input Through connectors J4 and J5, 8 channels of incremental encoder pulses (A, B, and C) and their associated home flags may be brought in for the two DSPGATEs on ACC-29 and its Opt.1. For those channels of DSPGATEs which are not used for MLDT interfacing, these encoder inputs may be directed to the DSPGATEs by removing the corresponding ExB jumpers. These inputs are expected to be TTL level compatible. Internal pulls up resistors (3.3K) are installed on all inputs through J4 and J5 connectors. However, they are not protected by PMAC's usual opto-isolation circuitry. DSPGATE General Purpose Outputs The eight compare equal signals (EQU9 to EQU16) and the eight general-purpose outputs (OUT9 to OUT16) associated with the two DSPGATEs on ACC-29 and its Opt. 1 are available for user functions. J2 and J3 connectors provide the outlet. Jumpers E18, E19, E21, and E22 determine the signals' polarities. These signals may be defined by M-variable assignments. Their addresses correspond to those for the third and the fourth PMAC DSPGATEs (please see the I/O map section in PMAC User's Manual). Incompatibility with ACC-24P/V The maximum number of DSPGATEs used with each PMAC is four providing 16 channels of feedback. The DSPGATEs are used for PMAC's specific motor/ amplifier/ encoder (or MLDT) interface functions. Each DSPGATE handles these functions for four channels. Thus, the basic 4 axes PMAC talks to one DSPGATE. A PMAC with Opt.1 talks to two on-board DSPGATEs providing eight channels. An ACC- 29 with one DSPGATE provides 12 channels. Its Opt. 1 provides the remaining allowable 4 channels. Since the ACC-24, the Axis Expansion board, also provides channels , it follows then: whenever an ACC29 is interfaced with a PMAC, the Axis Expansion board (ACC-24) should not be used with the same PMAC. An Example of Parameter Setup As an example, consider the case of the connection a MLDT device with Type B timing to an ACC-29 through its first channel (LDTI1 and LDTO1). Assume that the G value provided by the manufacturer is 9.05 ms/in., and the stroke length is 45 inches. Also, assume that PMAC is running with its default servo cycle frequency (442 ms per servo cycle). In addition, suppose that the limit switches and the home switch corresponding to this MLDT are connected to the first channel of the first DSPGATE on PMAC itself. Servo Cycle Extension Setup Using the expression for the Required Servo Extension explained above, we get Required Servo Extension = (40 x 9.05)/442= Since this value is less than one, no servo cycle extension is required in this case (I160=0). In addition, the default jumper position for interrogation pulse frequency generation for DSPGATE 1, E25A, Connection to ACC-29 13

18 must be installed. Note that this installation also limits any other MLDT channel connected to the first DSPGATE to be less than 48 inches long. Encoder Conversion Table Setup Since the address of the first DSPGATE s timer register (LDT channel 1) is $C020, the following command should be used to set up the conversion table: WY:$720,$30C020,$7FFFFF, Note that, as explained previously, the filter size of 6 is very much application dependent. In addition, the conversion table editor screen in the PMAC Executive software may be used to facilitate the conversion table setup I-variable Setup Since the conversion table entry for this channel is now three words long, I103=$10722 I104=$00722 I125=$xxC000 Note that bit 16 of I103 is set in order to specify that the "software method" of home position capture is required. As explained above this method is always required for "homing" with MLDTs. However, since MLDTs are absolute sensors, homing is often not needed. In addition, since the home/limit/ amplifier fault inputs are directed to the channel one of the first DSPGATE in PMAC, I125 is made to point to this gate's address. The most significant 8 bits of I125 should be set according to the user's particular desired operating mode (see PMAC Users Manual). Timing Considerations Since the transducer is assumed be interfacing with ACC-29 through the type B timing pattern, E23 should be installed (default setting) to provide the 1 ms interrogation pulse. Jumper E1A need not be installed since the interrogation pulse is immediately echoed back by the processing head electronics of the transducer. However, regardless of the setting of E1A, the correct displacement measurement will be made for the type B timing pattern. Note that for the type A and the type C transducers ExA must be installed. Also, setting I940=0 will take care of the required "pulse and direction" mode for the type B timing through channel 1 of this ACC-29. If using PMAC version 1.14 or later, it is necessary to use motor setup variable Ix10 to get the absolute power on position from the MLDT sensor (see PMAC Users Manual & Addendums for version 1.14 & above). In this case I110 = $18c020 is required for correct power on position registration for channel 1 of MLDT. A List of Tested MLDT Devices The following MLDT devices have been successfully interfaced and tested with PMAC through ACC-29 at Delta Tau's Motion Control Laboratories: Temposonics II RPM MTS Systems Corporation, Sensor Div. BOX Research Triangle Park NC Tel: (919) Connection to ACC-29

19 Quik-Stik Magnetek Controls, Gemco Electric 1080 N. Crooks Rd. Clawson, Michigan Tel: (313) GYRG Norstat Inc. P.O. Box 377 Hibernia,N.J Tel: (201) BTL Balluff Inc Holton Dr. Florence, KY Tel: (606) Connection to ACC-29 15

20 Interface Board for: Magnetostrictive Linear Displacement Transducer (M L D T) 4/8 channels 7.50 in. (190.5 mm) J2 1 E18 1 E17 E20 1 E19 E21 E24 U2 J1 J4 J3 1 E22 E23 J5 J6 J7 E9 E10 E J8 E26A E25A E26B E25B E26C E25C E25D E26D E25E E26E E26F E25F E25G E26G E26H E25H E25I E26I E1A E4A E1B E2A E4B E3A E2B E3B 1 1 E12 E13 E27A E27B E27C E27D E27E E5A E8A E5B E6A E8B E6B E7A E7B U1 TB1 E16 E14 E15 E33 E32 Figure 1: Layout of PMAC's ACC in (98.6 mm) 16 Connection to ACC-29

21 CPU J2 PMAC-PC JMACH1 P1 Limit, Home, Amp. Enable Switches etc. to ACC-8D or ACC-8P J1 ACC-29 (MLDT Interface board) J8 P1 Up to 8 MLDT connections Figure 2: PMAC Connection to ACC-29, note that for PMAC-VME the same connector is used. ACC-29 cannot be connected to PMAC-STD. Connection to ACC-29 17

22 18 Connection to ACC-29

23 CONNECTOR PINOUTS J2 (10 Pin Header) Pin # Symbol Function Description Notes 1 OUT9/ Output General Purpose Output Low true * 2 EQU9/ Output General Purpose Output Low true ** 3 OUT10/ Output General Purpose Output Low true ** 4 EQU10/ Output General Purpose Output Low true ** 5 OUT11/ Output General Purpose Output Low true ** 6 EQU11/ Output General Purpose Output Low true ** 7 OUT12/ Output General Purpose Output Low true ** 8 EQU12/ Output General Purpose Output Low true ** 9 +V In or Out +5V Power I/O +V= +5V to +24V +5V out of ACC to +24V in from external source. Diode Isolation from ACC GND ACC-29 Common Digital Ground * Controlled by bit 14 of the corresponding DSPGATE s status/ Control register. **Controlled by bit 13 of the corresponding DSPGATE s status/ Control register. This connector brings out the four Compare-Equal signals (EQU9 to EQU12) and the four general-purpose output signals (OUT9 to OUT 12) associated with the first DSPGATE on ACC-29. Jumpers E18 and E19 determine the signals polarities. For MLDT interfacing this connector is not required. J3 (10 Pin Header) Pin # Symbol Function Description Notes 1 OUT13/ Output General Purpose Output Low true * 2 EQU13/ Output General Purpose Output Low true ** 3 OUT14/ Output General Purpose Output Low true ** 4 EQU14/ Output General Purpose Output Low true ** 5 OUT15/ Output General Purpose Output Low true ** 6 EQU15/ Output General Purpose Output Low true ** 7 OUT16/ Output General Purpose Output Low true ** 8 EQU16/ Output General Purpose Output Low true ** 9 +V In or Out +5V Power I/O +V= +5V to +24V +5V out of ACC to +24V in from external source. Diode Isolation from ACC GND Acc-29 Common Digital Ground * Controlled by bit 14 of the corresponding DSPGATE's Status/ Control register. **Controlled by bit 13 of the corresponding DSPGATE's Status/ Control register. This connector brings out the four Compare-Equal signals (EQU13 to EQU16) and the four general purpose output signals (OUT13 to OUT 16) associated with the second DSPGATE on ACC-29 Opt 1. Jumpers E21 and E22 determine the signals polarities. For MLDT interfacing this connector is not required. This connector is only available on ACC-29 with Opt. 1. Connector Pinouts 19

24 J4 (34 Pin Header) Pin # Symbol Function Description Notes 1 +5V Output Power Supply For encoders 2 +5V Output Power Supply For encoders 3 DGND Common PMAC Common For encoders 4 DGND Common PMAC Common For encoders 5 CHC11 Input Encoder C Channel Channel 11 6 CHC12 Input Encoder C Channel Channel 12 7 CHB11 Input Encoder B Channel Channel 11 8 CHB12 Input Encoder B Channel Channel 12 9 CHA11 Input Encoder A Channel Channel CHA12 Input Encoder Chan. Channel HF411 Input Home Flag 4 Channel HF412 Input Home Flag 4 Channel HF 311 Input Home Flag 3 Channel HF312 Input Home Flag 3 Channel HF211 Input Home Flag 2 Channel HF212 Input Home Flag 2 Channel HF111 Input Home Flag 1 Channel HF112 Input Home Flag 1 Channel CHC9 Input Encoder C Channel Channel 9 20 CHC10 Input Encoder C Channel Channel CHB 9 Input Encoder B Channel Channel 9 22 CHB10 Input Encoder B Channel Channel CHA9 Input Encoder A Channel Channel 9 24 CHA10 Input Encoder A Channel Channel HF49 Input Home Flag 4 Channel 9 26 HF410 Input Home Flag 4 Channel HF39 Input Home Flag 3 Channel 9 28 HF310 Input Home Flag 3 Channel HF219 Input Home Flag 2 Channel 9 30 HF210 Input Home Flag 2 Channel HF19 Input Home Flag 1 Channel 9 32 HF110 Input Home Flag 1 Channel DGND Common Acc-29 Common 34 DGND Common Acc-29 Common This connector brings in all the encoder channels and the home flags associated with the first DSPGATE on ACC-29. For MLDT interfacing this connector is not required. All of the input signals are internally pulled up to +5V. However, no opto-isolation circuitry is included for these inputs. For encoder input through this connector, Jumpers E1B through E4B should be removed for channels 9 to 12 respectively. Note that for a given channel either an incremental encoder or a MLDT device may be used. 20 Connector Pinouts

25 J5 (34 Pin Header) Pin # Symbol Function Description Notes 1 +5V Output Power Supply For encoders 2 +5V Output Power Supply For encoders 3 DGND Common PMAC Common For encoders 4 DGND Common PMAC Common For encoders 5 CHC15 Input Encoder C Channel Channel 15 6 CHC16 Input Encoder C Channel Channel 16 7 CHB15 Input Encoder B Channel Channel 15 8 CHB16 Input Encoder B Channel Channel 16 9 CHA15 Input Encoder A Channel Channel CHA16 Input Encoder A Channel Channel HF415 Input Home Flag 4 Channel HF416 Input Home Flag 4 Channel HF 315 Input Home Flag 3 Channel HF316 Input Home Flag 3 Channel HF215 Input Home Flag 2 Channel HF216 Input Home Flag 2 Channel HF115 Input Home Flag 1 Channel HF116 Input Home Flag 1 Channel CHC13 Input Encoder C Channel Channel CHC14 Input Encoder C Channel Channel CHB 13 Input Encoder B Channel Channel CHB14 Input Encoder B Channel Channel CHA13 Input Encoder A Channel Channel CHA10 Input Encoder A Channel Channel HF49 Input Home Flag 4 Channel 9 26 HF410 Input Home Flag 4 Channel HF39 Input Home Flag 3 Channel 9 28 HF310 Input Home Flag 3 Channel HF219 Input Home Flag 2 Channel 9 30 HF210 Input Home Flag 2 Channel HF19 Input Home Flag 1 Channel 9 32 HF110 Input Home Flag 1 Channel DGND Common Acc-29 Com. 34s DGND Common Acc-29 Com. This connector brings in all the encoder channels and the home flags associated with the second DSPGATE on ACC-29 with Option 1. For MLDT interfacing, this connector is not required. All of the input signals are internally pulled up to +5V. However, no opto-isolation circuitry is included for these inputs. For encoder input through this connector, Jumpers E5B through E8B should be removed for channels 13 to 16 respectively. Note that for a given channel either an incremental encoder or a MLDT device may be used. Connector Pinouts 21

26 J6 (16 Pin Header) Pin # Symbol Function Description Notes 1 DCLK Output A to D Clock Channel 9 to 12 2 BDATA3 Output A to D Data Channel 9 to 12 3 ASEL4/ Output Channel Select Bit 0 Select for channel 9 to 12 4 ASEL5/ Output Channel Select Bit 1 Select for channel 9 to 12 5 CNVRT45 Output A to D Convert ADC convert for 9 to 12 6 ADCIN3 Input A to D Data ADC data for channel 9 to 12 7 OUT9/ Output Output 9 See also J2 8 OUT10/ Output Output 10 See also J2 9 OUT11/ Output Output 11 See also J2 10 OUT12/ Output Output 12 See also J2 11 HF49 Input Input Channel 9 See also J2 12 HF410 Input Input Channel 10 See also J2 13 HF411 Input Input Channel 11 See also J2 14 HF412 Input Input Channel 12 See also J V Output +5V Supply 16 GND Common ACC-29 Common This connector contains miscellaneous I/O signals related to the first DSPGATE on ACC-29. Typically, it is used for direct connection to an ACC-28 (the four channel analog-to-digital converter board). For MLDT interfacing this connector is not required. For an ACC-29 with 50 MHz clock, jumper E27B should be installed to provide the correct ADC clock frequency of MHz. J7 (16 Pin Header) Pin # Symbol Function Description Notes 1 DCLK Output A to D Clock Channel 13 to 16 2 BDATA4 Output A to D Data Channel 13 to 16 3 ASEL6/ Output Channel Select Bit 0 Select for Channel 13 TO 16 4 ASEL7/ Output Channel Select Bit 1 Select for Channel 13 TO 16 5 CNVRT67 Output A to D Convert ADC convert for 9 to 12 6 ADCIN4 Input A to D Data ADC data for Channel 13 to 16 7 OUT13 Output Output 13 See also J2 8 OUT14/ Output Output 14 See also J2 9 OUT15/ Output Output 15 See also J2 10 OUT16/ Output Output 16 See also J2 11 HF413 Input Input Channel 13 See also J2 12 HF414 Input Input Channel 14 See also J2 13 HF415 Input Input Channel 15 See also J2 14 HF416 Input Input Channel 16 See also J V Output +5V Supply 16 GND Common Acc-29 Common This connector contains miscellaneous I/O signals related to the second DSPGATE on ACC-29 Opt. 1. Typically, t is used for direct connection to an ACC-28 (the four channel analog-to-digital converter board). For MLDT interfacing this connector is not required. For an ACC-29 with 50 MHz clock, jumper E27B should be installed to provide the correct ADC clock frequency of MHz. 22 Connector Pinouts

27 J8 (37 Pin DB Connector)1,2,3 Pin # Symbol Function Description Notes 1 LDTO1 Output Interrogation Pulse Channel 1 2 LDTI1 Input Return Pulse Channel 1 3 LDTO2 Output Interrogation Pulse Channel 2 4 LDTI2 Input Return Pulse Channel 2 5 LDTO3 Output Interrogation Pulse Channel 3 6 LDTI3 Input Return Pulse Channel 3 7 LDTO4 Output Interrogation Pulse Channel 4 8 LDTI4 Input Return Pulse Channel 4 9 LDTO5 Output Interrogation Pulse Channel 5 10 LDTI5 Input Return Pulse Channel 5 11 LDTO6 Output Interrogation Pulse Channel 6 12 LDTI6 Input Return Pulse Channel 6 13 LDTO7 Output Interrogation Pulse Channel 7 14 LDTI7 Input Return Pulse Channel 7 15 LDTO8 Output Interrogation Pulse Channel 8 16 LDTI8 Input Return Pulse Channel 8 17 LDTGND Common ACC-29 LDT Common See E33 description 18 LDT15V Input ACC-29 LDT Power Supply See E32 description 19 LDTGND Common ACC-29 LDT Common See E33 description 20 LDTO1/ Output Negative Interrog. Pulse Channel 1, do not GND if not used. 21 LDTI1/ Input Negative Return Pulse Channel 1, do not GND if not used 22 LDTO2/ Output Negative Interrogation Pulse Channel 2, do not GND if not used 23 LDTI2/ Input Negative Return Pulse Channel 2, do not GND if not used 24 LDTO3/ Output Negative Interrogation Pulse Channel 3, do not GND if not used 25 LDTI3/ Input Negative Return Pulse Channel 3, do not GND if not used 26 LDTO4/ Output Negative Interrogation Pulse Channel 4, do not GND if not used 27 LDTI4/ Input Negative Return Pulse Channel 4, do not GND if not used 28 LDTO5/ Output Negative Interrogation Pulse Channel 5, do not GND if not used 29 LDTI5/ Input Negative Return Pulse Channel 5, do not GND if not used 30 LDTO6/ Output Negative Interrogation Pulse Channel 6, do not GND if not used 31 LDTI6/ Input Negative Return Pulse Channel 6, do not GND if not used 32 LDTO7/ Output Negative Interrog. Pulse Channel 7, do not GND if not used 33 LDTI7/ Input Negative Return Pulse Channel 7, do not GND if not used 34 LDTO8/ Output Negative Interrog. Pulse Channel 8, do not GND if not used 35 LDTI8/ Input Negative Return Pulse Channel 8, do not GND if not used 36 LDTGND Common Acc-29 LDT Power Supply See E33 description 37 LDT15V Input Acc-29 LDT Power Supply See E32 description This is a 37-pin DB connector used for interfacing with up to 8 channels of MLDTs. 1 Channels 5 to 8 are operative only if ACC-29's Option 1 is installed. 2 To take full advantage of the opto-isolation feature of ACC-29 a separate power supply input should be brought in through this connector. If this is not possible, by installing jumpers E33, and E32 the "digital" power supply may be used for both sides of the opto-isolators. However, this voids the optoisolation feature of the board. 3 If differential interface signals (LDTIx, LDTIx/ and LDTOx, LDTOx/) are not used, the corresponding negative signals should be left floating. In addition, jumpers E9 through E16 should be set correctly for their respective channels. Connector Pinouts 23

28 TB1 (4 Pin Terminal Block) Pin # Symbol Function Description Notes 1 GND Common Digital (PMAC Side) See E33 description Common 2 +5V Power Digital (PMAC Side) Power Supply 3 +12V Power " See E32 description Supply 4 Not used This is a 4-pin terminal block which provides a alternative power supply input for standalone applications outside the PC bus. The +5V power supply input is intended for digital side of the on-board opto-isolation circuits. However, it is possible to bring in the +12V and +5V power supplies for the circuits on the MLDT side of the opto-isolation through TB1. To do this, jumpers E32 and E33 must be installed. (Note: the installation of these jumpers voids the opto-isolation feature of ACC-29). 24 Connector Pinouts