How to manually test CAMAC modules
Contents
1. eee eee eene 6 TESTING BRANCH COUPLERS BC AND CRATE CONTROLLERS CC ee eeeee eee eee eren 7 BRANCILCOUPEBER pietre d gene tease 7 CERATEXONTBOLELEERAC 26 E 7 READ AND WRITE TESTS SYSTEM TO BRANCH BRANCH TO 5 5 8 TESTING INPUT REGISTER AND OUTPUT DRIVER MODUDLSES e eee eene eene eee eene eese eatenus 10 butter t 11 MODULE TEST PRELIMINARIES erre deii e eere boe Ho eeu e coi iau etes s 12 RAS WAL OA BIT INPUT REGISTER 8 eee ee 12 OD45 DUAL 4 8 OU TLPUINDRIV lee ae 13 pec arte 14 25 15 PR2402 AND PR2403 PARALLEL INPUT 17 TESTING PR2403 PARALLEL INPUT REGISTER sersan a A 18 OD2407 DUAE 24 BIFOUTPUT DRIVER pes ead bees EU teh ds 19 TESTING THE RGO 32BIT COUNTER MODULE t eias2. Test REG1 1 16 Move the test cable to the lower connector on the module Toggle the switch A1 to the right 1 and repeat the above tests If all LED s in the lower group on the OD48 and those on the test box agree the module is working correctly If some of the LED s on the test box are not illuminated it may be simply a bad cable connection So check the cable connectors are properly seated before deciding if the module is faulty TESTING THE OD2411 This is a 48 channel 40mA 30V O P Register with handshake and is used in the WHT NASMYTH crate to provide the velocity demand control bits to the CW and CCW instrument rotator servos This module functionally is the same as the OD48 The difference being that the connectors on the module are standard 37way D types and not the 31way high density D type as used on the OD48 module The cable labelled OD2411 is required for testing this module and plugs into the plastic test box The module connectors are labelled OUTPUTS A and B instead of REG 0 and REG 1 but to test this model follow the procedure above as for an OD ORA8 Output A AO F16 Output B A1 F16 John Mills CAMAC TEST PROCEDURES 14 HYTEC 450 4 24 BIT INPUT OUTPUT REGISTER These WHT modules are used to read the data from the absolute encoders The inputs and outputs are differential pairs and conform to RS422 423 standards To test this module a special test box is available see description on pag
3. To set the RGO32BIT COUNTER to an initial known value there are inputs for both the encoder 1ppr and ZEROSET pulses The encoder data needs to be continually updated thus the counter module needs to be CLOCKED at a constant rate This also needs to be referenced to Universal Time UTC due the rotation of the Earth and the apparent movement of celestial objects across the sky 20Hz 50 5 signal which comes from the Time Service and thus referenced to UTC is used to clock the RGOS2BIT COUNTERS for this purpose There are 3 GREEN Leds below the main 32 bit display to show these actions These being labelled from the bottom up e 1PPR e ZERO e CLOCK The main 32 bit LED display uses RED Leds set in blocks of four which show the binary weighting of the counts John Mills CAMAC TEST PROCEDURES 21 TEST SETUP USING A BEI INCREMENTAL ENCODER The image below shows the test setup using a BEI incremental as the pulse generating source A co axial lead with LEMO connectors takes the 20Hz output from the FREQUENCY GENERATOR to the CLOCK input connector of the module This emulates the 20Hz signal from the Time Service F one ee i js Figure 19 RGO32bit counter test setup 1 Between the encoder and the counter module a special line driver box is used to convert the TTL outputs from the LEAD LAG and 1PPR of the encoder to differential pair opto
4. BR CPR 4 1 is fitted into slots 15 16 This allows modules in the lower branch crate to be tested when either or both of the switches labelled as BR16 on the test controller are toggled to the right John Mills CAMAC TEST PROCEDURES 3 THE BRANCH CRATE The lower crate is a BRANCH crate Although a single system crate can be used to test most of the modules in use at the ING using a two crate system has the advantage that the more complex modules such as crate controllers branch couplers and branch terminators can also be checked out if suspect The branch crate is fitted with a standard CRATE CONTROLLER which always occupies slots 24 25 It should be noted there are several models of crate controllers in use at the ING Some are of the earlier CC A1 types and others are the more recent CC A2 models There are also variations between different manufactures GEC FISHER etc For example some have C and Z push buttons for performing a crate re initialisation whilst others use a centre biased C Z toggle switch However they all perform the same function and are interchangeable The number of the BRANCH is determined by in which slots the BRANCH COUPLER module in the SYSTEM crate is placed In the WHT the branch coupler in the system crate occupies slots 19 20 This when under computer control determines the branch and the three crates daisy chained from it to be on B6 In the test rack the branch coupler occupies slots 15 16 which wo
5. Mills CAMAC TEST PROCEDURES 9 TESTING INPUT REGISTER AND OUTPUT DRIVER MODULES There are a variety of these modules in use Some types are only used in the WHT and others in the INT JKT systems These being WHT system 450 4 24 bit twisted pair input and output register 52w D connectors RA8 Dual 24 bit input register 31way D connectors e OD48 or OR48 Dual 24 bit output driver output register has less current drive e 002411 Dual 24 bit output register 37w D type connectors INT JKT system PR2402 Dual 24 bit input register standard TTL inputs also used in WHT PR2403 Dual 24 bit input register with opto isolated inputs 002407 Dual 24 bit output driver To test these modules special test boxes are available which provide a 24 bit input function using switches and a 24 bit output display using LED s Connections are via 37way D sockets and are labelled as to which is an INPUT or an OUTPUT connection There is also a third connector but this is never used and is marked as such DEAD ER T3 124 4 7t ML I 2 3 TAL Te E IR we 2 xs bs ue xem xr P L9 Figure 7 Input Register and Output Driver test boxes These boxes are essentially the same and both can be used for module testing However when testing the WHT OD OR48 or the IR48 modules use the box shown on the left referred to as the plastic test box as the test cables for these modul
6. TCS Some of these signals are now obsolete but recently changed what was the 50Hz output to 20Hz This is the timing signal used on all telescopes to strobe clock the incremental encoder up down 32 bit counters and would normally come from the Time Service and referenced to UTC Other useful signals still used and available from this module are the 1MHz square wave and the 1 pulse of 20005 per second These signals are needed when testing CAMAC modules such as the ED012 pulse generator and the millisecond generator BASIC SETTINGS FOR THE SC TST 1 TEST CONTROLLER The SC TST 1 contains two rows of switches for Operation 1 and 2 see Fig 2 allowing module address sub address and functions to be set up or modules in branch crates to be checked The test module can work in 3 modes determined by a 3 position toggle switch 1 Up Continuous clocking at 1MHz 2 Down Slow speed clocking at 10Hz 3 Centre Single step operation using the MAN CYCLE switch John Mills CAMAC TEST PROCEDURES 3 Figure 2 SC TST 1 Test Controller Normally the continuous mode CONT switch up as shown is used This clocks the CAMAC system at its normal 1MHz rate The setup as shown is used to test the read and write bits in the SYSTEM crate The DTM4 monitor display should be in slot NT and the WGR2403 word generator in slot N4 As we will be reading from the word generator as the first operation and writing the configuration of the WGR2403 swi
7. the DTM4 as well as on the test box IMPORTANT as these modules use Hughes connectors ensure the test cable connector is squarely aligned before clamping down the finger screw John Mills CAMAC TEST PROCEDURES 19 Figure 18 OD2407 Test Controller setup This INT module has two 24 bit output registers The output connectors are 38way Hughes types These being OUTPUT A upper connector module sub address 0 F16 OUTPUT B lower connector module sub address A1 F16 Test OUTPUTA 0 16 Using the OD2407 test cable and either the metal or plastic test box connect the cable to OUTPUT A upper socket It should be noted that the 38way Hughes connectors on this module have the polarising sleeve reversed between OUTPUT A and OUTPUT B On the upper connector the cable is at the top of the plug on the B side the cable is at the bottom of the plug as shown in the photo With the SC TST 1 set up as shown in Figure 18 toggle the switches on the WGR2403 to produce the following bit patterns Write allones 111111111111111111111111 Write all zeros 000000000000000000000000 Alternate bits 101010101010101010101010 Reverse bits 010101010101010101010101 Check that both the read and the write groups of LED s displayed on the DTM4 and the LED s on the test box conform to the word generator switches This is important as the data displayed on the DTM4 module may be correct but the data sent out from the module connector could
8. this Refer to the User Manual for more information John Mills CAMAC TEST PROCEDURES 21 012 Clock Pulse Generator Equipment needed 1 Frequency Generator module as used for the RGO 33bit counters 2 WGR 241 Word Generator 3 Anoscilloscope and the Marconi DFM Set to Period Milliseconds LED Indicator TMhz Cock Input co ux Lema 4 x TIL outputs 00 05 Lema 4 cleck outputs timia Lema 1 PROCEDURE Connect a Lemo cable between the 1MHz output of the frequency generator and the 1MHz input socket of the EDO12 A cable with a large and small LEMO connector fitted for this use is in the box of test cables Set up the BCNAF for the EDO12 and Word generator e g WGR N4A0 FO ED012 N8 AO FO Initialise the test crate using the C and Z switch Set the WG switch 7 to bit 1 all the rest at O i e set the word to 64 Enable the ED012 s internal rate multiplier with setting switches on the test module to F26 A1 Now reset the EDO12 for a normal write cycle F16 0 Plug in a test lead from SK to the oscilloscope and DFM these are connected in parallel and check a 500nS pulse is present and the DFM set to PER A Ms reads a value of 156 24milliseconds Now set the WGR switches 4 7 and 8 01 41 i e bits 8 64 128 set to generate a word of 200 This equates to a generated 50005 pulse of 20Hz 50 5 See MAP below 0 0 0 1 0 0 1 1
9. value e g 1024 2048 4096 and the highest value with this unit 8192 COARSE and FINE knobs control the velocity of the bit rate sent These set usually to their maximum values The two toggle switches are 1 Count direction UP U or DOWN D 2 Mode of operation CONTINUOUS C or BURST B The push buttons ON and OFF will start or stop the counts being sent to the encoder module In the photo the settings correspond to an UP count of 8192 with BURST mode selected Thus when the ON button is pushed a single stream of 8192 pulse will be sent at full velocity rate to the module under test John Mills CAMAC TEST PROCEDURES 26 USING THE SIMULATOR To use the simulator after the cable has been connected to the module take the crate off line and perform a C Z This resets all the counter registers to zero Make sure the RGO32Bit counter is receiving the 20Hz clock signal from the frequency generator Put the crate back on line and push the ON button With the value of 8192 selected the LED s on the module will count up in binary fashion but finally stopping with just one displayed This being bit 15 See photo below Another point regarding the operation of the simulator and demonstrated in the image is the CLOCK and ZEROSET green Leds are illuminated but not the 1PPR indicator There is a push button on the simulator labelled Z M Zero Marker for emulating the ZEROSET pulse but there is no switch or push bu
10. 0 0 20 2 1 2 4 8 16 32 64 128 256 512 Bit 1 Word generator switches X Bit 10 Check the DFM shows a value of 49 999mS 10 Check the remaining outputs SK3 to SK9 that this 20Hz signal is present If so the EDO12 is working correctly John Mills CAMAC TEST PROCEDURES 28 HYTEC ADC1232 Analogue to Digital Module There are several versions of ADC modules in use but they all have similar characteristics and use the same CAMAC commands for addressing them The HYTEC ADC1232 being the most common one in use There are 32 input channels Channels 1 to 16 are on the upper 37way D connector and channels 17 to 32 on the lower 37way D connector The ADC1232 samples to 12 bits resolution These ADC modules are primarily used for measuring the temperature sensors fitted on the trusses of the telescopes and on the mirror To test these modules there is a special Break Out Box BOB This allows input voltages from the Precision Voltage Generator which has a thumbwheel switch for selecting voltages in small increments which can be applied to the input channels of the ADC module The BOB cables are fitted with 37way standard D type connectors one male the other female so the box can also be used in series with the ADC to measure for example the voltages coming in from the temperature sensors The terminal pins on the BOB are arranged as such that pins 1 to 16 are the ADC input channels Ve and pins 20 to 36 are the OV return
11. 16 and C2 set to 1 e Operation 2 right hand column BR and C switches set to 0 Perform read or write operations only within the Branch crate e Operation 1 left hand column switches BR16 and C2 set to 1 e Operation 2 right hand column switches BR16 and C2 set to 1 From the above it can be seen in the case of performing read or write operations only using the System crate the BR and C switches on the TST 1 would be e Operation 1 left hand column BR and C switches set to 0 e Operation 2 right hand column BR and C switches set to 0 Note Switches set to the left 0 Switches toggled to the right 1 John Mills CAMAC TEST PROCEDURES 4 CRATE INTER CONNECTIONS Connections between the branch coupler in the system crate and the branch crate controller are made using a standard CAMAC DATAWAY cable which comes fitted with Hughes 132 pin connectors A shorter cable of the same specification connects the crate controller to the branch terminator The cable connectors are fitted with a polarising sleeve over the fastening screw which ensures the connector can only be fitted in one orientation VERY IMPORTANT Always take great care when removing or inserting these cables If the connector is not perfectly aligned with the socket on the module it is very easy to bend or break a male pin or worst still damage a female socket The individual sockets are very difficult to replace and there is now only one ext
12. 2 23 24 25 DRAWING No oystem crate test REV 1 0 AUTHOR E J Mills FILENAME test system crate vsd SYSTEM CAMAC DATE 30 5 2010 Figure 25 Testing the System crate John Mills CAMAC TEST PROCEDURES 3l CAMAC TESTING BRANCH CRATE ADDRESS e 2 GEN april BT 6502 CC 2089 WGR 241 FREQUENCY A2 CRATE LAM GENERATOR BRANCH CONTROLLER TERMINATOR R E EH CRATE SETUP FOR TESTING e FA THE FH RGO32BIT COUNTER MODULE CAMAC CAMAC DATAWAY DATAWAY 1mS Sec n n n n nUnUnUnUnUn n nOee o O O O O oo oo eo eo oo R 2 1 2 3 4 5 6 7 8 9 101112 13 14 15 16 17 18 19 20 21 22 23 24 25 DRAWING Branch crate REV 1 0 AUTHOR E J Mills FILENAME test branch crate vsd SYSTEM DATE 7 5 2010 Figure 26 Branch crate John Mills CAMAC TEST PROCEDURES 22
13. 402 has two 24 bit input registers The 58way Hughes connectors labelled INPUT A upper and INPUT B lower There is also a push button for clearing out the data from the input registers The modules sub addresses are INPUT A upper connector AO FO INPUT B lower connector A1 FO Using the PR2402 test cable and either the metal or plastic test box connect the cable to INPUT B lower socket It should be noted that the 58way Hughes connectors on this module have the polarising sleeve reversed between INPUT A and INPUT B On the upper connector the cable is at the top of the plug on the B side the cable is at the bottom of the plug as shown in the photo With the SC TST 1 set up as shown in Figure 16 toggle the switches on the box to produce the following bit patterns Write allones 111111111111111111111111 Write all zeros 000000000000000000000000 Alternate bits 101010101010101010101010 Reverse bits 010101010101010101010101 Check the Read and Write LED s on the DTM4 conform to the switch settings Now move the cable to INPUT A upper socket Toggle the switch A1 on the SC TST 1 to the left This sets A 0 to read from INPUT A Perform the tests as described above and again check the LED s on the DTMA follow the switches Bits failing to be detected are usually caused by a damaged input buffer chip and these are easy to replace A similar effect may be produced if the test cable is not fully inserted so check th
14. CS is used in a generic sense and refers to both the hardware and software which performs this function Under normal use commands to are sent or received via a DEC ALPHA computer running VMS and performs various tasks such as reading the telescope s position encoders sending the demanded velocity rate moving the dome adjusting the focus etc A CAMAC system always consists of a SYSTEM CRATE and normally one or more BRANCH crates The CAMAC BUS consists of 24 read write lines which are used to pass data between the TCS and the outside world The bus also carries lines for module number decoding module sub addressing function codes control signals and interrupt handling In CAMAC terminology these interrupts are known as LAM s Look At Me The bus is extended out to the other crates in the system referred to as branch crates using a high density twisted pair DATAWAY cable Although commands are sent or read by a computer in normal use it is possible to run a CAMAC system manually and it is for this non standard mode of operation why this document has been written It enables many different types of modules to be tested and likewise repaired without the need of a computer Throughout this document will use the standard convention of nomenclature for CAMAC commands The only difference being that these will now be generated by setting up switch patterns on a test controller rather than being sent by a computer According to CA
15. GISTER AND OUTPUT DRIVER TEST BOXES 21 DIM mM MET M E IR48 TEST CONTROLLER SETUP TRA BEST eL E D M LE a a TEST SETUP FOR OD OR48 MODULES OD OR48 TEST CONTROLLER SETUP HY TEC 450 4 TEST SEPUP he ate etie 450 4 TEST CONTROLLER SETUP PR AOD TEST SETUP e inesse diese Sait e MEE ES PR2402 TEST CONTROLLER SETUP 00220721 2 P ture cM e dE UE M d UE M OD2407 TEST CONTROLLER SETUP RGO32BIT COUNTER TEST SETUP 1 RGO32BIT COUNTER SETUP 255 ettet ade RGO32BIT COUNTER TEST CONTROLLER SETUP GAEBRIDGE ENCODER SIMULATOR 15 0 BREAK OUT BOX FOR ADC MODULES TESTING THE SYSTEM CRATE BRANCH CRATE DOCUMENT HISTORY Revision Revision 1 0 First released June 2010 E J MILLS 2 0 2014 E J MILLS Added the procedure for testing the EDO12 Clock Generator module John Mills CAMAC TEST PROCEDURES OVERVIEW CAMAC Computer Automated Measurement And Control is a control data acquisition system based on CRATES and MODULES which was originally developed in the 1960 s for the nuclear research industry CERNE It conforms to a standard both in mechanical and electronic specifications CAMAC is used to interface the various mechanisms of the telescope to and from the TCS Telescope Control System The abbreviation T
16. MAC convention the BCNAF protocol is B Branch number 1 to 7 System crate is always BO CO C Crate number 1 to 7 Determined by a switch on the Crate Controller X Module slot number 1 to 23 olots 24 25 reserved for Crate Controller A Module sub address 0 to 15 Input Output A or B channels etc F Function 0 to 31 Read write test or set LAM etc John Mills CAMAC TEST PROCEDURES 2 LAYOUT OF RACK FOR CAMAC TESTING AND REPAIRS The image below shows the test rack used for CAMAC module testing which is located in an office on the first floor of the INT first door on the left after entering the floor from the east stairwell This rack has been left in a state to be usable at any time It is powered from the mains sockets behind on the wall but these are switched off when the equipment is not in use Two crates are used SU rrrPM rwbeA bbeb bbbbt SE teeewee tee yess es sss teed A ini wm M Figure 1 Test crates THE SYSTEM CRATE The upper crate is the SYSTEM crate which contains a standard EXECUTIVE CONTROLLER type MX CTR 3 and a manual test controller SC TST 1 It should be noted that a link cable with 4 pin LEMO connectors must be present between the executive controller OUT and test controller IN rear EMO sockets This is called the Arbitration Bus and if missing or broken the test system will not work A BRANCH COUPLER
17. Operation 1 switches 16 41 2 1 4 1 e Operation 2 switches N1 1 F16 1 Send the following bit patterns using the 24 switches on the BRANCH crate WGR2403 Check that the WRITE LEDS on the SYSTEM crate DTM4 agree Write allones 111111111111111111111111 Write all zeros 000000000000000000000000 Alternate bits 101010101010101010101010 Reverse bits 010101010101010101010101 If any bits are missing or refuse to change state change the CRATE CONTROLLER for a known working spare and repeat the above test If the problem persists change the BRANCH COUPLER for a known working spare and repeat the above test Providing the WGR2403 and DTMA are working ok then changing a CC or BC should resolve the problem of which module is faulty If any of the above tests fail it will generally identify either a faulty CRATE CONTROLLER or BRANCH COUPLER There could be a problem in that a fault situation may exist if the crate number is changed but the Branch Coupler test as described at the beginning of this section should identify this when the crate number switch is changed and if a corresponding LED on the Branch Coupler does not come on It is worth carrying out these tests again using a different crate number if such a problem is suspected Another indication of the heath of the system is to check the OPERATION 1 and 2 and Q and X LED s on the TST 1 These should all be on when running the TST 1 in Continuous 1MHz clocking mode John
18. SYSTEM crate this determines the branch number to be 16 The branch crate number can be set from 1 to 7 In these tests we will use 2 as the crate number So ensure the rotary switch is set to this number These tests also assume that a DTM4 dataway monitor is in slot NT and a WGR2403 Word Generator is in slot N4 in BOTH crates Set up the SC TST 1 Test Controller as follows TEST 1 Read WGR2403 in SYSTEM crate and write to the DTM4 in the BRANCH crate John Mills Figure 5 System to Branch crate transfer Operation 1 All switches set to 0 except 4 1 e Operation 2 switches 16 41 2 1 N1 1 F16 1 Send the following bit patterns using the 24 switches on the SYSTEM crate WGR2403 Check that the WRITE LED s on the BRANCH crate DTM4 agree Write allones 111111111111111111111111 Write all zeros 000000000000000000000000 Alternate bits 101010101010101010101010 Reverse bits 010101010101010101010101 If any bits are missing or refuse to change state change the CRATE CONTROLLER for a known working spare and repeat the above test If the problem persists change the BRANCH COUPLER for a known working spare and repeat the above test Providing the WGR2403 and DTMA are working ok then changing a CC or BC should resolve the problem of which module is faulty CAMAC TEST PROCEDURES 8 TEST 2 Read WGR2403 in BRANCH crate and write to the DTM4 in the SYSTEM crate Figure 6 Branch to System crate transfer e
19. THE ISAAC NEWTON GROUP OF TELESCOPES CAMAC TESTING PROCEDURES A GUIDE ON HOW TO MANUALLY TEST CAMAC MODULES REV 2 0 Author J Mills Date May 2014 Source eng document archive electronics camac manuals test procedure rev2 doc This document is also available in PDF format in the public html directory at http www ing iac es eng electronics misc test procedure rev2 pdf TABLE OF CONTENTS THE ISAAC NEWTON GROUP OF TELESCOPES cce eeuee eoe e eene enne enne sempus esa e eaae eene rasa keen uae anao 0 LIST OE FIGURES 5 ninos MD Saiten EN 1 TOC IVE INE TENSE ORY ctetu dod a uet nU 1 OVERVIEW 2 LAYOUT OF RACK FOR CAMAC TESTING AND 5 3 3 THE BRANCH CRA TB 4 CRATEINTER CONNECTIQONS iteitsustes 5 2226 E EIE ERE N ER Ho ES 5 BASIC SETTINGS FOR THE SC TST 1 TEST 21 00 111 5 WGR2403 WORD GENERATOR AND DTM4 DATAWAY MONITOR TESTING
20. The image above shows the test setup using the plastic test box with the OD48 test cable plugged into REG 0 upper connector The LED s in the test boxes need a supply so a special power cable is required which plugs into the crate s 9 pin front panel D connector This is nominally at 6V but this voltage is reduced to 5 within the test box The OV earth return is made via the test cable John Mills CAMAC TEST PROCEDURES 13 Figure 12 OD OR48 Test Controller setup This WHT module has two 24 bit output registers The output connectors are high density 31way D type These being REG 0 upper connector module sub address AO F16 REG 1 lower connector module sub address A1 F16 Test REGO 0 16 Using the OD48 test cable and the plastic test box connect the cable to REG 0 upper socket With the SC TST 1 set up as shown in Figure 12 toggle the switches on the WGR2403 to produce the following bit patterns e Writeallones 111111111111111111111111 e Write all zeros 000000000000000000000000 e Alternate bits 101010101010101010101010 e Reverse bits 010101010101010101010101 Check that the upper group of LED s illuminated on the OD48 and the LED s on the test box are the same This is important as the local display on the module may be working but the data sent out from the module connector could be faulty It is not unknown for an output driver chip to be damaged and this test will show if this is so
21. annel to be tested This completes the ADC test John Mills CAMAC TEST PROCEDURES 29 Conclusion In this document have covered the testing of most of the CAMAC modules in use at ING Those have not being the LP34 millisecond generator and the 3340 5232 communications modules as used in the INT JKT The LP34 modules are easy to test using the in house built CAMAC Frequency Generator and the User Manuals for these modules are readily available The 3340 RS232 serial communications modules are somewhat difficult to test and require a 220 terminal or similar to be connected to the 25way D socket on this module Carlos Martin knows how to test these modules John Mills Rev 2 0 May 2014 John Mills CAMAC TEST PROCEDURES 30 CAMAC TESTING TESTING THE SYSTEM CRATE ARBITRATION BUS 4 PIN LEMO Switches on modules are shown in correct positions to produce an alternate 1010 bit pattern OPERATION 1 READ FROM WORD GENERATOR IN SLOT 4 Address BO CO 4 AO FO OPERATION 2 WRITE TO DATAWAY MONITOR IN SLOT 1 Address BO CO N1 AO F16 0 0 O O O O O 90 24 Oe eO O eO Oe eO O eO W O O O O O O DATAWAY JUUUUMUUUUUUTM UU UU UU UU JOUR UU LINK EEE O O O O O O O O O O 1 O O O O 9 01000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 2
22. at also before deciding if the module is faulty TESTING A PR2403 PARALLEL INPUT REGISTER These modules are only used in the INT JKT CAMAC system The difference being the A and B inputs are OPTO ISOLATED whereas on the PR2402 the input circuitry accepts standard TTL signals Testing the PR2403 module uses the same procedure as above However use the plastic test box for these modules and change the middle toggle switch in the group of three from STD to OPTO John Mills CAMAC TEST PROCEDURES 18 OD2407 DUAL 24 BIT OUTPUT DRIVER These modules are only used in the INT JKT CAMAC systems They are used for driving hardware such as relays and generating commands for moving the dome focus and instrument turntables For testing this module use the WGR2403 word generator in slot 4 0 FO to write data to the OD2407 in slot 8 AO or A1 with F16 being set The DTMA4 will automatically display the read and write data present on the bus and does not need to be addressed as such Figure 17 OD2407 test setup This photo shows the OD2407 module under test using the metal test box As with the plastic test box the LED s on the metal box require a Vcc supply also Connect the special power cable as shown in the photo In this example OUTPUT B lower connector is being tested and the switches on the word generator set to produce an alternate 010101 bit pattern This can be seen displayed on both the read and write groups of LED s on
23. be faulty It is not unknown for an output driver chip to be damaged and this test will show if this is so Test REG1 1 16 Now move the test cable to the lower connector This is the setup as shown in Figure 17 Toggle the switch A1 Operation 2 group to the right 1 and repeat the above tests If the LED s on both output channels are in agreement with the word generator switches then the module is working correctly If some of the LED s on the test box are not illuminated it may be simply a bad cable connection So check the cable connectors are properly seated before deciding if the module is faulty John Mills CAMAC TEST PROCEDURES 20 TESTING THE RGO 32BIT COUNTER MODULE GENERAL INFORMATION These modules are used on all telescope CAMAC systems and convert the data from the INCREMENTAL encoders to an UP DOWN binary count which the TCS requires to determine the angular position of where the telescope is pointing An incremental encoder produces two trains of pulses known as LEAD and LAG The optical plate or tape band is made in such a way to produce these 90 degree phase shifted signals Depending on what signal is detected first by the steering logic within the counter module e g LEAD gt LAG or LAG gt LEAD determines whether the encoder is moving in a CW CCW direction The electronics used for this is known as a QUADRATURE DETECTOR Another consideration is that an incremental encoder needs a datum or
24. blems with 450 4 modules are missing or stuck bits and the above test is more than adequate to show this type of fault John Mills CAMAC TEST PROCEDURES 16 PR2402 AND PR2403 PARALLEL INPUT REGISTERS These modules are used extensively in the INT and JKT for providing input signals to the TCS from many of the telescope s mechanisms and console push buttons that are still in use PR2402 modules are also used in the WHT CLIP crate for reading some of the engineering console switches and status from the dome and shutters In all telescope SYSTEM crates a PR2402 is used to supply the TCS with UTC data from the Time Service Figure 15 PR2402 test setup This photo shows a PR2402 under test using the metal test box As only the switches on the box are used the box doesn t require the Vcc supply derived from the crate s 9 pin D connector In this example the switches have been set to random ON or OFF positions and the bits activated can be seen displayed the DTM4 in slot 1 The two toggle switches at the top on the box are set to CAMAC and STAT n b The OPTO STD option doesn t work Leave the switch on the side of the box set to STD John Mills CAMAC TEST PROCEDURES 17 IMPORTANT As these modules use Hughes connectors the pins or sockets on the connectors can be easily damaged Ensure the test cable connector is squarely aligned before clamping down the finger screw Figure 16 PR2402 Test Controller setup The PR2
25. e 10 A nice feature about this setup is that both the INPUT and OUTPUT registers can be tested together x ET 9Seoccodeccc00000000 0Q Pee cae 000000000000000000000009 d 7 mH E d n e 4 1 v d b 23 gt E Figure 13 HYTEC 450 4 test setup The photo shows the test box in use In this example all 24 bits have been set which can be seen displayed on the DTM4 and Branch Terminator in the branch crate as well as on the test box The 450 4 OUTPUT connector is the upper one the INPUT connector being the lower Ensure the cables labelled as 450 4 OUT and 450 4 IN are inserted into the appropriate connectors There are two more cables coming from the test box labelled TO and FROM ENCODER but for this test they are not required Below the LED s are test points for the 24 differential input and output connections and can be used for monitoring purposes using a meter or oscilloscope John Mills CAMAC TEST PROCEDURES 15 The test box requires a 5V supply of at least 2A and the power cable seen to the right connects to a bench PSU The input signals are derived from 24 toggle switches on the box their state being shown by the row of red LED s below The green LED s are drive
26. eae resp e eee evan epo 21 GENERAL INPORMAT ICON iua susct coc m a Seed he eonun onset sop Ee ood epp eae 21 TEST SETUP USING BEI INCREMENTAL 2 0 2224 2 0000000000000000055 22 ENCODER SIMULATOR eene detnr ae nonne te anre Eka dare nee eda eco da e aaepe een aac 26 USING THE SIMUEA TOR it adu irse me 27 2555 27 MULTIDAC Digital to Analogue Converter 27 EDOI2 Clock 408 552 28 HY TBC ADCI 32 CAnalopued0 DioHal 56 bet op o 29 I I I MINI I A I MIN LUE 30 LIST OF FIGURES FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 FIGURE 16 FIGURE 17 FIGURE 18 FIGURE 19 FIGURE 20 FIGURE 21 FIGURE 22 FIGURE 23 FIGURE 24 FIGURE 25 FIGURE 26 TES D CRATES nee en eee SC TST 1 TEST CONTROLLER BRANCHCOUPEERS S EA CRATE CONTROLLER SYSTEM TO BRANCH CRATE TRANSFER BRANCH TO SYSTEM CRATE TRANSFER ettet ttt INPUT RE
27. ed i e Once for each rotation of the encoder shaft e Check that the DTM4 and the Led display on the RGO23bit counter are in agreement e Turn the encoder shaft for a time then stop and push the ZERSET button on the line driver box e Check that the DTM4 and the Led display on the RGO23bit counter are in agreement This completes the general data transfer tests on the RGOS2bit counter using the test BEI encoder More information and the full set of CAMAC commands can be found in the RGO 32BIT CAMAC COUNTER USER MANUAL A copy of which is in the office where the CAMAC testing is done John Mills CAMAC TEST PROCEDURES 25 GAEBRIDGE ENCODER SIMULATOR This piece of test equipment can also be used for testing RGOS2Bit counter modules Although using the BEI incremental encoder in my experience is a better method this unit can be set up to send a given number of pulses to the encoder module This is useful if missing bits are suspected as it is very difficult to move the BEI encoder shaft to generate a known number of counts The simulator is very easy to use The cable plugs directly into the 37way D connector on the counter module 1 11 n Mi pit 11 A 57 FH Figure 22 GAEBRIDGE encoder simulator In the photo the simulator is setup to send 8192 pulses to the counter module The thumb wheel switch can be set to any value up to 9999 but its common sense to select a value which equals a standard binary
28. es will only fit into these connectors which are mounted without the clamping plate The same applies for testing the OD2411 module Another caveat is to use this box for testing the PR2403 input registers opto isolated inputs The metal box has this facility also but no longer works Unfortunately we have no documentation for these boxes and the circuitry within the metal box is very fragile The boxes are also fitted with 3 toggle switches to set the mode of operation Set these to CAMAC other position is CF never used SIAT other position is PULSE SID other position is OPTO on plastic test box John Mills CAMAC TEST PROCEDURES 10 For testing the HYTEC 450 4 modules a special test box is available 0000000000 99990966966990909 gt e9909900000000 M 0000000000909090 0999020909090 ee FROM 458 4 TO ENCODER t eececceccecec ene e us x a Figure 8 HY450 4 Test Box This box has a dual function 1 Using the 2 cables labelled 450 4 INPUT and OUTPUT It can be used for testing the module in a standalone mode which will be described later 2 Using all 4 cables two are marked as TO and FROM encoder the box can be used to monitor real time encoder data by un plugging an encoder cable from the 450 4 module and connecting the box in a series configuration For this to work all the switches must be set to DIRECT toggled up The centre and bottom
29. he green LED s on the 32 bit counter will stay illuminated Only by taking the branch crate OFF LINE and performing a C Z will these bits and displays be cleared As the 20Hz signal is being supplied from the Frequency Generator the CLOCK Led should re appear once the crate is brought back on line Using the BEI encoder to test the module is simple Just rotate the shaft and depending on the direction the red LED s on the module s 32 bit display will move either UP or DOWN However if the SC TST 1 is not setup to address the module although the red LED s will change with movement the data from the module will not be transferred to the bus and that is what we need to test Note On the encoder body and shaft are marked two reference lines The point where these two lines cross is when the 1ppr signal is generated Figure 21 RGO32bit counter test Controller setup The diagram shows for Operation 1 the address of the module at N8 and sub address A1 FO selected The sub address will be changed from 0 to 4 during the test procedure Operation 2 is set to write data to the DTM4 module 1 0 F16 Test the Clock 1ppr ZERSET signals e the crate off line and perform a C Z All the LED s on the module should be OFF e Put the crate back on line again and the CLOCK Led should come on e Move the encoder shaft slowly and when the 1ppr reference lines pass check the 1ppr LED comes on Now push the ZEROSET button o
30. here are still problems with either WGR2403 or DIM4 these are easy to repair but these modules are generally very reliable IMPORTANT 7hese test modules must be in full working order before carrying out tests for suspected faults on either a Branch Coupler or Crate Controller module For this reason it is best to test these modules in the SYSTEM crate If for some reason bits are missing or stuck when sent across a branch it s more likely to be a fault with a crate controller or branch coupler rather than with the WGR2403 or DTMA4 test modules John Mills CAMAC TEST PROCEDURES 6 TESTING BRANCH COUPLERS BC AND CRATE CONTROLLERS CC The usual method of checking these modules would be to perform a read or write instruction from the system crate to the branch crate and then reverse the procedure A failure to read or write data over a branch could be due to either module Experience has shown it is generally the CC which fails but on rare occasions the BC was faulty Figure Branch coupler BRANCH COUPLER BC In the test system crate this module occupies slots 15 16 and is selected by setting a BR16 switch on the TST 1 to 1 Ensure both crates are powered up and the branch crate is on line The 3 way switch OFF INTERNAL ON is usually left in the ON position This should illuminate the Branch Demand ENABLED led on the BC On the CC rotate the crate number selector switch threw positions 1 to 7 Check the SH Leds 1
31. isolated inputs which the counter module requires The input connector is standard 37way D type The line driver box requires a 5V supply and a bench PSU is used for this To simulate the ZERSET pulse a push button the line driver box provides this signal John Mills CAMAC TEST PROCEDURES 27 Figure 20 RGO32bit counter setup 2 The above image shows the line driver box bench PSU and sitting above that the GAEBRIDGE ENCODER SIMULATOR which will describe how to use later When testing this module there is an important point to take into consideration A standard CAMAC bus has 24 read and write lines but this module reads in 32 bits of data To achieve this the data is transferred to the bus by reading in two 16 bit blocks The module s sub address lines being set to either 0 to read the lower 16 or LSB bits or 1 to read the upper 16 or MSB bits There are also two modes of reading the encoder data into the RGOS2bit counter 1 Clocked in continuously at 20Hz normal operation 2 he data is read in when a Strobe Pulse from either the 1PPR or ZEROSET signal is detected In practice the second mode of operation would only be required when the telescope is ZEROSET at the start of observing and from then on the encoder modules are STATICISED from the 20Hz signal from the Time Service John Mills CAMAC TEST PROCEDURES 23 It should also be noted that when a 1PPR or ZEROSET pulse in or the CLOCK signal is detected t
32. n from the module s output register The toggle switches have 3 positions but only the centre and down positions are used These are labelled as 5V and However due to internal buffering and chip inversion the logic states sent to the 450 4 input register are Switch Centre Bit 0 Switch Down Bit 1 Figure 14 450 4 Test Controller setup Both read and write data operations are performed simultaneously on the same module Operation 1 To read the switch data N8 AO FO read input register Operation 2 To write data to LED s N8 A1 F16 overwrite output register Use the switches on the 450 4 test box to generate the following bit patterns e Writealones 111111111111111111111111 e Write all zeros 000000000000000000000000 e Alternate bits 101010101010101010101010 e Reverse bits 010101010101010101010101 Because the input data is being passed back out of the module both the GREEN and RED Leds should be in agreement As mentioned for the previous I O module tests bad connection between the test cable and module connector can cause problems with bits missing so ensure these connectors are pushed in fully The 450 4 is quite a complex module with a host of CAMAC commands for performing other operations such as clearing setting or testing the LAM bit There are also commands for clearing a register after reading it A full set of instructions along with the connector pin details are readily available The usual pro
33. n the line driver box Check that the ZERO Led comes on If all this works ok the module is detecting these pulses correctly Test the LSB bits are being read onto the bus in continuous mode Using Register 1 e A 0 0 switch A1 in diagram toggled to the left e Take the crate off line do a C Z and put the crate back on line The red LED display should be blank If the encoder is just even lightly touched either most certainly the MSB upper 16 bits will be displayed or just a few of the low order bits displaying Now move the encoder shaft rapidly The LED s will either count up down in pure binary depending on the direction of rotation e Check the DTM4 displays show the same bit pattern as the red LED s on the RGO32bit counter module If all looks ok the LSB encoder bits are being read correctly Test the MSB bits are being read onto the bus in continuous node Using Register 1 e A 1 0 switch A1 set as in Figure 21 John Mills CAMAC TEST PROCEDURES 24 e Perform the test as above The bits displayed on the DIM4 will now be changing much more slowly This is because the encoder needs to complete a full 16 bit 65 535 counts before bit 16 the lowest order bit in the MSB range will change state e Check again that the DIM4 and LED display on the RGO32bit counter are in agreement When the encoder is rotated and the bits are counting UP it would take many turns of the encoder shaft to check out the full 32 bit
34. ns Write allones 111111111111111111111111 Write all zeros 000000000000000000000000 Alternate bits 101010101010101010101010 Reverse bits 010101010101010101010101 Figure 10 1 48 test setup Check the lower group of LED s on the IR48 and also the R W LED s on the DTM4 agree with the switches This is shown in the photo and with an alternate 101010 bit pattern generated Now move the cable to the REG 0 connector upper socket Toggle the switch A1 on the SC TST 1 to the left This sets A 0 to read REG 0 Perform the tests as described above and check the upper group of LED s on the IR48 follow the switches Bits failing to be detected are usually caused by a damaged input buffer chip and these are easy to replace A similar effect may be produced if the test cable is not fully inserted so check that also before deciding if the module is faulty John Mills CAMAC TEST PROCEDURES 12 OD48 DUAL 24 BIT OUTPUT DRIVER Note There are two versions of this module used in the WHT the OD48 and the OR48 For test purposes these modules are the same The only difference being the OD48 can sink more current For testing these modules we use the WGR2403 word generator in slot 4 AO FO to write data to the OD48 in slot 8 AO or 1 and F16 being set The DTMA will automatically display the read and write data present on the bus and does not need to be addressed as such Figure 11 Test setup for OD OR48 modules
35. raction tool for Hughes connectors that still works on site Experience has shown it is best to partially insert the connector then carefully wiggle the plug to ensure it will seat squarely before tightening down the screw The screw only needs to be finger tight MODULES GENERALLY LEFT IN TEST CRATES Both the system and branch crates contain DIM4 dataway monitor and a WGR24093 24 bit Word generator These can also be found in the CAMAC systems on all ING telescopes and are left there for test purposes if needed The WGR2403 consists of 24 toggle switches left O right 1 for generating bit patterns on the bus There is also a switch at the top for setting the LAM The DTMA4 displays via LED s 24 bit read and write operations on the bus There are also LED s which display the status of the A module sub address and F function lines Other signals such as the 51 52 and Busy lines and the Z and C lines Initialise and Clear commands and the X and Q responses are also displayed This is a useful module in that data can be also written to it using AO F16 which is good for showing if there are any bits stuck or which refuse to clear on the bus In the branch crate although in what slot it is located is unimportant is a FREQUENCY GENERATOR module This was built in house many years ago 1986 by Nuria a student who still remember This module was made to provide standard frequencies for test purposes that are used by the
36. range but doing this for a minute or so is good enough to show that the MSB bits are being read onto the bus A further test is to rotate the encoder shaft so the bits count DOWN All the MSB will then be displayed when a 32 bit zero count is passed To reset the counter registers take the crate off line and perform a C Z This will return the counter displays to a cleared condition Another way to clear the counter is by sending the CAMAC command F9 AO To do this set the switches on the SC TST 1 Operation 1 column to AO and F9 and the counter should reset to zero Test the LSB bits are being read onto the bus in strobed mode Using Register 2 These tests are basically the same as before the difference being that data will only be transferred to the bus when 1ppr signal or a ZEROSET pulse is received Setthe SC TST 1 to A22 0 e Turn the encoder shaft Data will now only be transferred when the 1ppr is detected i e Once for each rotation of the encoder shaft e Check that the DTM4 and the LED display on the RGO293bit counter are in agreement e Turn the encoder shaft for a time then stop and push the ZERSET button on the line driver box e Check that the DTM4 and the LED display on the RGO293bit counter are in agreement Test the MSB bits are being read onto the bus in strobed mode Using Register 2 Setthe SC TST 1 to A 3 0 e Turn the encoder shaft Data will now only be transferred when the 1ppr is detect
37. reference point to set the counter module to a known value or starting position Along with the lead and lag tracks there is also a 1 pulse per revolution 1ppr signal generated by the encoder The BEI incremental encoders used on the INT produce 16 000 bits counts from the lead and lag tracks plus a very narrow 1ppr pulse for every revolution completed However in the case of a telescope a more precise reference is required and this is achieved by an external signal sent from either a proximity switch usually an inductive sensor or a slotted opto switch In both of these systems a metal flag attached to the telescope axes moves past or through the sensor thus generating a pulse known as the ZEROSET signal As this signal can only occur when the telescope axes are in a certain position we now have a way of determining exactly where the telescope is pointing and a means for the TCS to set the encoder count to a known value In practice the ZEROSET pulse is logically ANDED within the encoder line driver box with the encoder 1ppr so that a very accurate angular position is determined for the telescope axes In the case of the INT JKT the ZEROSET occurs when the telescope is vertical at the ZENITH and the Hour Angle at 0 degrees and the DEC axis 28 degrees With the WHT being an Alt azimuth mounting this is determined with the ALTITUDE elevation axis at 90 degrees 89 48 and the AZIMUTH axis at 300 degrees 298 35
38. s Figure 24 Break out box for ADC modules Pins 1 20 are Channel 1 0 A 0 Pins 2 and 21 are Channel 2 0 A 1 Pins and 22 are Channel 3 F 0 A 2 Pins 4 and 23 are Channel 4 0 A 3 test channels 17 to 32 on the lower connector the F bit is changed to F 1 Pins 1 and 20 are Channel 17 1 0 Pins 2 and 21 are Channel 18 1 1 Pins 3 and 22 are Channel 19 1 2 Pins 4 and 23 are Channel 20 1 A 3 test the ADC as with previous tests Insert the module into slot N8 e g test ADC Channel Toggle the switch A2 on the SC TST 1 to 1 All other A and switches are set to 0 Operation 1 8 A2 FO read ADC channel 3 Operation 2 1 AO F16 write to the DTM4 1 Connect the Ve and Ve leads from the Precision Voltage Source across pins and 22 of the BOB 2 he User Manual will give the information regarding binary counts for a particular voltage input think 10mV LSB bit 0 is the lowest voltage change that the ADC will detect 3 Step through the voltage increments using the thumbwheel switches on the Precision Voltage Generator and check what bits are displayed on the DTMA The binary counts should match the voltage selected 1 bit The Users manual gives instructions on how to calibrate the ADC if required To test Channels 17 to 32 use the lower connector and toggle the F1 switch to 1 and set the switches to the number of the ch
39. switch positions 5 and OV simply generate a logic 1 or 0 state for module bit pattern testing In the photo the switches have been set to produce an alternate 1010 bit pattern TEST CABLES These are kept in box near the test rack and are as follows OD OR48 Output Driver IR48 Input Register OD2411 Output driver PR2402 3 Input Register OD2407 Output Driver al os John Mills CAMAC TEST PROCEDURES 11 MODULE TEST PRELIMINARIES Figure 9 IR48 Test Controller setup For standard module tests prefer to use the BRANCH crate This is simply because the test rack has a pull out tray and cables running between the test box placed on the tray and the module under test are closer together As the following tests will be performed using the Branch crate and the module under test will be inserted into slot N8 the SC TST 1 needs to be configured as shown in Figure 9 That is Operations 1 and 2 are executed using BR 16 and C22 N8 1 FO reads REG 1 of the IR48 and 1 AO F16 writes the data to the DTMA 1848 DUAL 24 BIT INPUT REGISTER This WHT module has two 24 bit standard TTL input registers These being REG 0 upper connector module sub address AO FO REG 1 lower connector module sub address 1 FO Using the IR48 test cable and the plastic test box connect the cable to REG 1 lower socket With the SC TST 1 set up as shown in Figure 9 toggle the switches on the box to produce the following bit patter
40. tches to the DIM4 second operation and no branch crate used the TST 1 switches as shown are correct The BCNAF order would be Operation 1 Read WGR2403 switches in slot N4 BO CO N4 AO FO Operation 2 Write result to DTM4 in slot N1 BO CO N1 AO F16 The LED s on both the READ and WRITE displays should show the state of the switches as set on the word generator e g Set all bits high 111111111111111111111111 Clear all bits low 000000000000000000000000 Alternate bits 101010101010101010101010 as shown in image Heverse bits 010101010101010101010101 WGR2403 WORD GENERATOR AND DTM4 DATAWAY MONITOR TESTING The above test is also useful for checking the correct operation of the WGR2403 and DIM4 modules The switches on the word generator can suffer with dirty contacts which may cause bits to fail LED buffer chips on a DIM4 or the LED s themselves rarely fail but it s not unknown A more likely problem with missing or intermittent bits are the gold plated edge connectors which can tarnish or dirty contacts within an edge connector socket mounted on the back plane within the crate Simply cleaning the module contacts with a solvent cleaner usually cures these problems In the case of the internal edge connectors spray the solvent into the contacts then using a module which is missing the bottom locking screw there are plenty push it in and out several times to ensure the cleaner has worked its way into the contacts If t
41. to 7 on the BC corresponds to the crate number selected on the CC If this works the Branch Coupler is probably ok but further tests for reading and writing via the Branch crate to the System crate and then again but in the opposite direction will need to be carried out to confirm that both the BC and CC are functioning correctly Figure 4 Crate controller CRATE CONTROLLER CC Figure 4 shows the Crate Controller and Branch Terminator as fitted in the test branch crate LC The crate number 1 to 7 rotary switch is between the connectors To the left of this is a locking lever switch for taking the crate ON or OFF line Below that is a biased toggle switch for performing a crate Clear and Initialise C Z operation These three switches are present on all makes and models of crate controllers but not necessarily in the positions as shown It is always advisable to take the crate off line and execute a C Z before using the branch crate This will clear all module data registers and will extinguish any LED s that may be ON from a previous operation For example take the crate off line perform a C Z and put the crate back on line again Any LED s which come back illuminated may signify a stuck bit s on the bus if no read or write instruction from a module has been set up John Mills CAMAC TEST PROCEDURES 7 READ AND WRITE TESTS SYSTEM TO BRANCH BRANCH TO SYSTEM As the Branch Coupler is across slots 15 16 in the test rack
42. tton for a 1PPR test For this reason it is best in the first instance to use the BEI encoder for testing as this sends out a REAL 1ppr signal If the simulator is put in CONTINUOUS mode with the 8192 count selected this is a good method of testing for changes in the MSB bits as it can be left running for a long period which would be laborious if rotating the BEI encoder shaft by hand This completes the use of the encoder simulator and RGO32Bit counter tests TESTING MISCELLANEOUS MODULES MULTIDAC Digital to Analogue Converter The 9085 MULTIDAC modules as used in the INT JKT are easy to test All that is required is a LEMO cable with an open end which can be connected to a MULTIMETER This is set on a low voltage range The DAC uses 12 bit sampling and generates a 5 and 5V output voltage These modules are setup as such that a binary word of 2048 gives a OV zero volts output A data word of 4096 gives a 5V output and 0000 a minus 5V output Use the WGR2403 word generator in slot 4 to produce the binary word for the DAC to output these voltages The DAC under test would be setup say in slot N8 with an F16 or AO A1 A2 or A3 set on the SC TST 1 to write to the appropriate output channel There are 4 channels used on the INT There is a trim pot on the module for output voltage calibration The user manual will explain how to adjust this It should be noted the 9085 is no longer made and a HYTEC 640VSL substitutes for
43. uld equate to B4 as used on the INT system have used this branch number to simplify the use of the SC TST 1 test controller in that only toggling the switch B16 will enable read write operations via the branch crate As this test setup is only a two crate system the branch crate is fitted with a BRANCH TERMINATOR BT 6502 and mounted as always beside the crate controller and occupying slots 22 23 The branch crate address is determined by a rotary switch on the crate controller There are 7 positions thus a maximum of seven crates can be supported on a branch In the WHT three branch crates are used C1 C2 and C2 and all are on B6 Each crate controller is therefore setup up accordingly On the test branch crate this can be set to any number between 1 and 7 but normally have left this to be C2 Changing this number is required to test the functionality of branch couplers and crate controllers However whatever branch crate number is selected the same value must be enabled on the TEST CONTROLLER TST 1 for data transfers to or from the branch crate E g The branch and crate selection switches on the TST 1 would be set as thus Read from System crate and write to the Branch crate e Operation 1 left hand column BR and C switches set to 0 Operation 2 right hand column BR and C switches BR16 and C2 set to 1 Read from Branch crate and write to the System crate e Operation 1 left hand column BR and C switches BR
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