Model DRC-80 - Lake Shore Cryotronics, Inc.
Contents
1. EBE Bits 1 4 SW 10 A Display Sensor switch settings with bit 1 being the Least Significant Bit and bit 4 being the Most Significant Bit b Bit 5 N A c Bit 6 N A d Bit 7 Display Sensor 0 1 Bit 8 Scale EXPAND Mode 0 Button Out Normal 1 Button In Expanded Scale NOTE The expanded scale bit is set only if the button is in and the display temperature is below 100 0 K A chart which shows the pushbutton information and corresponding output character is shown below This is data represented by the first character of the Panel information variable or bits 5 8 above Output Bit Expanded Display Character Representation Scale Sensor 0 0000 4 0100 NO B 8 1000 YES A C 1100 YES B The SW 10A switch position is represented by the characters 1 9 and The 1 9 stands for positions 1 thru 9 the A stands for position 10 The switch position information is only present for the B display sensor When the A position is selected as display sensor the position is returned as zero When there is no position present for the B display sensor the switch position is returned as zero An example of the panel information for a DRC instrument that is in the expanded scale mode has B as display sensor and has an SW 10A position of 2 would look like C2 An example for a transmission for an instrument which has switch l of the IEEE address switch up at power on scale expand button in A as di2. LIST OF MATERIALS LAKE SHORE CAVOTRONICS ME El sa OB Np MACHINE FINISH 2 m DRC 80 IEEE E Ai SCHEMATIC 39 295 d a SIZE DRWG NO REVISION Eeer DESIGN ACTIVITY SCALE SHEET OF ERHEBEN NEN asia a See EESTI JD 22 R20 GND V of sensor 11 U10 7103A JG 5 1 a Oo gt O i PT TTT Ty Ty GJ 0 f 1 un 8052 ic MMM mM 1 I Ne ee amp 9 LA c c 110410 ulaji moje lt 28 ig c c m m i c Q O lt m gt I gt 0 U14 74LS 257 A A I H s C USA NOTES I Ce 1 U14 15 PIN 15 enable N 1 disable PIN 1 O A input 1 Binput 2 IS NOT PRESENT 5Vo CY R6 B 21 ue 7 LM308N a ume ECKED DAT DATE 679 XJ DRWG NO D 145 81 01 pug s pm SHORE CRVBTRORNS Westerville Ohio 43081 DRC 80 SCHEMATIC 2 100000000000 4 EH t C57 4 e JA U62 000000000000 CONTRACT NO DRAWN DATE DATE 7 19 m aa LAKE SHORE CRYOTRONICS Westerville Ohio
3. Initialize System Check for Input Overrange Is there an Overrange No Input A D Readings Is it a Valid Reading Yes Load Yes in Temperature Storage Area Input Display Sensor amp Switch Position Determine Voltage Temperature Table to be used Find Break Point dT Calculate Slope dv for that Break Point Find Multiply by a Add Check for Scale Expand Bit Is Scale Expand in Yes Set up Output Information and Decimal Point Drive for Format of XXX X 15 Temperature gt 100 Set up Output Info and Decimal Point Drive for Format of XX XX vtput Temperature to Display Software Flow Diagram for DRC 80 Digital Thermometer 2955 0781 Point is determined The program finds the correct break point for temperature determination by checking each breakpoint voltage to see if it is lower than the input voltage As the break point is found the temperature is calculated using the following equation T dT T BP AD dv BP where T is temperature in K is break point voltage Van is input voltage aT Spp is slope between successive break points Tap is break point temperature After the correct temperature has been calculated the program looks to see if the instrument is in the scale expand mode In this mode the front panel display converts to a resolut
4. User s Manual Model DRC 80 Digital Cryogenic Thermometer Obsolete Notice This manual describes an obsolete Lake Shore product This manual is a copy from our archives and may not exactly match your instrument Lake Shore assumes no responsibility for this manual matching your exact hardware revision or operational procedures Lake Shore is not responsible for any repairs made to the instrument based on information from this manual LakeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA Internet Addresses sales lakeshore com service lakeshore com Visit Our Website www lakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Obsolete Manual July
5. 23325 21911 20497 19083 17774 16464 15155 m DT 500DRC El Voltage Temperature Characteristic BP 30 29 28 27 26 25 24 Table 3 2 TEMP K ON ON Qn Un Ex FH Ww 9 WW W N PO kA LA Q O un CH Ln Un O NEMO O O O O AA O O OOO ON ON fF i gt O PROM VOLTAGE BRO F P 2 NN 2 S mm 6591 6567 6542 6518 6494 6470 6446 6355 6265 49179 6084 5994 5868 2742 5610 2490 5364 22221 2077 4934 4791 4648 4290 3932 3574 3216 2858 52200 2142 1784 1516 1247 0708 0170 9632 9011 8390 7769 7148 20527 _10 DT 500DRC E1 Voltage Temperature Characteristic BP 23 22 21 20 18 17 16 15 14 13 12 11 10 TEMP K 19 0 20 0 21 0 22 0 2340 24 0 25 0 26 0 2440 28 0 29 0 30 0 32 0 34 0 36 0 38 0 40 0 45 0 50 0 55 0 60 0 65 0 70 0 T2950 12439 80 0 85 0 90 0 95 0 100 0 105 0 110 0 115 0 120 0 125 0 130 0 135 0 140 0 145 0 150 0 155 0 PROM VOLTAGE en O O O O O O O O O O O A bh FH gt bh bh e O O O O O 5724 4922 4120 3317 2837
6. IN4006 IN4006 4006 IN4006 IN4006 MR501 MR501 IN743A IN743A IN4148 Hewlett Packard 5082 7651 Hewlett Packard 5082 7651 Hewlett Packard 5082 7651 Hewlett Packard 5082 7651 E 0781 CIRCUIT DESIGNATION Ul U2 U3 U4 U5 U6 U7 U8 09 010 011 U12 U13 U14 15 CIRCUIT DESIG or FIG NO TX1 INTEGRATED CIRCUITS DESCRIPTION 15V Positive Voltage Regulator 15V Positive Voltage Regulator 15V Negative Voltage Regulator SV Positive Voltage Regulator Temp Stabilizer Voltage Reference Current Source Operational Amplifier Current Source Driver Not Present Operational Amplifier A D Converter Building Block Timer Circuit A D Converter Building Block Microprocessor Unit Tri State 4 line to 4 line Multiplexers MISCELLANEOUS DESCRIPTION Main Fuse 3 AG Slow Blow 90V 125 3 4A 210V 250V 4 10A Fuseholder Power Transformer Power Cord 115V CEE Color Coded 230V Strain Relief Heat Sink for U4 MFR and PART NO 7815 7815 7915 7805 LM399H LM308N 3N163 OPO7EJ 71603 7555 8052 38P70 Plus Prom Memory Dependent 74L8 257 MFR and PART NO Bussmann MDL 3 4 Bussmann MDL 4 10 Littlefuse 342004A LSCI Supplied 696 107 Belden 17236 Belden 17740C Smith 939 Aavid 60130 020B 2335 0781 CIRCUIT DESIGNATION R1 R2 R3 R4 R5 R6 R7 R8 R10 R11 R12 R13 R14 R15 R16 R17
7. R18 R19 R20 R21 R22 R23 24 27 R101 R102 105 CIRCUIT DESIGNATION 51 53 54 55 S2 56 RESISTORS VALUE 3 74 10 Trimpot 20K Trimpot 4 75 499 Not Present Not Present Not Present RATING TYPE 1 Mt F 1 XW Mt F I Source Adjust Operational Amplifier Adjust 1 Mt F 1 MESE DRC 80 DRC 80 4 75K 1 xW MET 10K 1 ZW KSE 93 2 1 XW Meal 36 5K 1 xW Mt F 301K 1 xW Mt F 1 18K 1 xW RE AER 5K Trimpot A D Adjust 196 ohm 1 xW Mt F 107 ohm 1 xW MESE 121K 1 ZW 121K 1 xW Mt F 19 6K 1 SN MESES 4 75K 1 SM MESE 10 ohm 1 xW Mt F 4 7K 4 Element Resistance Network 3 74K 1 xW Mt F 330 ohm 4 Element Resistance Network SWITCHES DESCRIPTION MFR and PART NO Power Switch LSCI Supplied Scale Expand Switch LSCI Supplied Sensor B LSCI Supplied Sensor A 115 230 Switch Not Present LSCI Supplied Switchcraft DRC 80 DRC 80 E m DRC 80 BCD L A REPLACEABLE PARTS LIST CAPACITORS CIRCUIT DESIGNATION VALUE RATING TYPE C56 40232 100 Mylar C57 68 f 100V Poly C58 68 f 100 1 C59 68 f 100V Poly CONNECTOR CIRCUIT DESIGNATION DESCRIPTION MFR and PART NO J4 20 pin PC Mount Header T amp B Ansley 609 5022M INTEGRATED CIRCUITS CIRCUIT DESIGNATION USED IN PART NO U51 BCD L A 741 5175 052 BCD 741 5175 053 BCD 7415175 U54 BCD L A 741 5175 056 BCD only 74123 U61 L A only OP15FJ U62 L
8. check U12 Also check resistance string R15 18 for proper value and operation d A D Output The digit drives Pins 19 24 25 See of 110 26 and 27 are positive going Figure pulses and last for 200 clock pulses scan sequence is D5 on following MSD D4 D3 D2 and LSD page The BCD pins pins 20 23 are positive going signals that go on simultaneously with the digit de vice If not present and signals a b and c are correct replace 510 Pin 2 of 1013 This is the uP clock signal This is generated by an external RC net work with the help of the main processor If not present check 2 R21 C21 and U13 for proper 9 Sues operation 29 D5 UIO 19 _ x TL 0 24 D3 UIO 25 02 00 26 D1 UIO 27 MSB B8 N N UIO 23 B4 NN N N UIO 22 B2 N Y UIO 21 B1 NN SS UIO 20 20 40 msec Figure 5 1 DRC 80 A D Typical Output Signals 0781 30 0781 CIRCUIT DESIGNATION C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 17 C18 C19 C20 C21 C22 CIRCUIT DESIC Ji J2 J3 J4 JA SECTION VI DRC 80 REPLACEABLE PARTS LIST CAPACITORS VALUE RATING 470 uf 35V 470 uf 35V 470 uf 35V 2700 uf 25V 1 uf 100V uf 100 EE 100 68 uf 100V 150 uf 500V DOT uf 100V 330 pf 500 68uf 100V 142 AME 29V 330 pf 500 233 UE 100V 68 uf 100V 68 uf 100 68 uf 100 3
9. 1 Depress the power switch and observe that the display shows the proper temperature relative to the sample temperature The sensor and readout display should follow the curve in Table 3 2 This curve illustrates typical values expected of the DT 500 DRC or DT 500CU DRC 36 sensors If the diode or lead wires are shorted the display will read If the diode is connected backwards the display will read 428 0 for all curves the case of an open current or voltage lead the display will slowly drift higher in temperature The curves and appropriate PROM mark ings are given below Curve PROM U13 Version 3 Version 6 B Version 2 D Version 4 E Version 5 If the instrument or sensor does not agree with values listed in the table within the accuracy of the system consult sections on instal lation and or section on troubleshooting to determine the cause and cure of the malfunction 0781 A KELVIN FIGURE 3 1 FIGURE 3 2 teere 4 meaaaanaaaamaaaauuprueaeeseedesd422240 ee e nahme D VE RA CRYOGENIC THERMOMETER MODEL DRC 80 DRC 80 Front Panel A 9 Qo 17 DRC 80 Rear Panel 0781 DT 500DRC D Voltage Temperature Characteristic BP 30 29 28 27 26 25 Table 3 2 TEMP K 14 15 16 1 7 18 O O O O O PROM VOLTAGE k E NO RO RO RO No gt M2 RO RO NO NO P
10. 1981 Table of Contents Section I General Information 1 1 Introduction 1 2 Description 1 3 Major Assemblies Supplied 1 4 Ordering of Replacement or Additional Sensors II Installation Introduction Initial Inspection Power Requirements Grounding Requirements Installation Repackaging for Shipment 2 RO P ON Ui T Uto FS F gt Operating Instructions 3 1 Introduction 3 2 Controls Indicators Connectors 3 3 Temperature Readout 3 4 Analog Output of Temperature 3 4 1 Field Installation of DRC Options 8022 and 8025 3 5 Standard DT 500DRC and DT 500CU DRC 36 Curves 3 6 Rack Mounting the DRC 80 3 7 The 10 Sensor Selector Switch 3 8 Remove Parallel BCD Output Option 3 9 Interface Option 3 9 1 General IEEE Specifications amp Operation 3 9 2 Specific Operation of the DRC8 IEEE Interface Model 8024 3 9 3 Sample Programming 3 9 4 Field Installation of DRC IEEE Model 8024 IV Theory of Operation 4 1 Introduction 4 2 Detailed Description 4 2 1 Power Supplies 4 2 2 Precision Constant Current Source and Front Panel Switching 4 2 3 A D Converter and Microprocessor System 4 2 4 Software DRC 80 Cryogenic Thermometer 4 2 5 Digital Display Board Cal 5 1 Introduction 5 2 Test Equipment 5 3 General Remarks 5 4 Instrument Calibration 4 1 Current Source 4 2 A D Converter 4 3 Adjustment of Output Buffer 4 4 DRC8 L A Option Model 8025 5 5 Instrument Tests VI DRC 80 Replace
11. 43081 80 BCD L A PARTS LAYOUT DRWG NO REVISION B 203 81 01 CR1 1 3 CR2 CR5 uz 3 CASE L2 LOW Uo 3 C5 15 15 C6 ANALOG GN 7 159 C8 GND 4 er rs H SIZE DRWG NO REVISION B 178 81 01 e OF SS
12. 92921 1877 1299 1365 1239 1150 1080 0981 0909 0848 50797 0746 0630 0915 0399 0284 0159 0035 9911 9849 9780 9649 9518 9388 9257 29122 8988 8853 s8118 8584 8449 OILI 9173 8035 7896 27759 de DT 500DRC El Voltage Temperature Characteristic BP TEMP K 160 0 165 0 170 0 175 0 180 0 185 0 190 0 195 0 200 0 205 0 210 0 215 0 220 0 225 0 230 0 235 0 240 0 245 0 250 0 232940 260 0 265 0 270 0 2 540 280 0 285 0 290 0 295 0 300 0 305 0 310 0 315 0 320 0 325 0 330 0 PROM VOLTAGE 0 7620 0 7482 0 7344 0 7202 0 7060 0 6918 0 6777 0 6635 0 6493 0 6351 0 6210 0 6068 0 5926 0 5789 0 5651 0 5514 0 5377 0 5246 0 5115 0 4984 0 4853 0 4722 0 4588 0 4454 0 4320 0 4186 0 4045 0 3904 0 3763 0 3622 0 3476 0 3330 0 3184 0 3038 0 2893 E i 0781 3 4 Analog Output of Temperature The analog output of temperature takes the display temperature and converts it to an analog signal which has a sensitivity of 10 mV K under normal operation Under scale expand this signal increases to 100 mV K below 100K due to the movement of the decimal point The analog output voltage is located on the monitor connector Key 9 of Figure 3 2 3 4 1 Field Installation of DRC Options 8022 and 8025 The installation of either the Model 8022 option Parallel BCD or 8025 10 mV K can be done as foll
13. A only DAC HP16D 063 BCD L A 7420 RESISTORS CIRCUIT DESIGNATION VALUE RATING TYPE R76 2 MEG 1 SN Mt F R86 2 MEG 1 5 Mt F R87 511K 1 SN Mt F R88 50K Trimpot R89 50K Trimpot 0781 This Page Intentionally Left Blank ez ENT EN Gate Kt Jee OR O 000000000000000000 omo 10050000 vin 000000 _ 00000000000000000000 A5 000000000000 00000000000 9 Jj 100 000 2 HT Q 5 sin O UE E 9 0000000 23 ub 7 n 000000000000 00000000000 u 00000000 55 amp 2 K 1 1 H oza 3 O O Tin dino COMM or 9 3000000 j00 SW 10A CONNECTOR PECIF NOMENCLATURE OR DESCRIPTION MATERIAL OR NOTE LIST OF MATERIALS i LAKE SHORE CRVOTRORICS IB KS 6 Ei Westerville Ohio 43081 CS DRC 80 PARTS LAYOUT TE DO NOT SCALE DRAWING AR mas Id UD DRWG REVISION OF w o K 9 xil F R 9 Ee 2 2 a g 295078 CR2000 0 E uoo AER tg OT FORO Ss 8 cE RN Ap J U202 U215 ceo n XB e 000000 0000000 2 e cpgr00000000000000000000 S gt Towel 0201 R200 0000000000000000000 o 8905020 i 100000000 U210 U211 4204 000000 ooooooolof nononono C210 C207 Pete HN 00000000 0212 U213 R211 218 000000 DODODO 00000000 000000
14. Its wide measurement range covers the spectrum of most cryogenic temperature needs The dual sensor input enables two sensors to be used concurrently either for verification or for monitoring temperature at different points This multi input capability can be further expanded with the Model SW 10A 10 position Selector Switch which conveniently mounts side by side with the 80 in a standard 35 rack opening Sensor selection is via front panel pushbuttons The display sensor voltage is fed to an Analog to Digital converter pair A D where it is converted to a digital voltage signal proportional to the sensor voltage The multiplexed BCD outputs from the A D are sampled and verified by the microprocessor The microprocessor executes a program which takes the sampled sensor voltage and using break point voltage and temperature information stored in a tabulor array calculates the associated Kelvin temperature to better than 0 01 Kelvin micro processor then outputs the temperature information to the display board The decoder driver decodes this temperature data latches the informa tion and drives the display digits The sensor display voltage is also available as a buffered output through the monitor plug on the rear of the instrument The m croprocessor also controls the BCD and IEEE options 4 2 Detailed Description A detailed description of the operation of the DRC instrument is outlined in the following sections The Figures r
15. display will then return the data from the instrument 10 06 5 5 20 PRINT 20 PRINT 40 PRINT PANEL P 50 PRINT TEMPERATURE T 60 END Set the address switch to 6 by putting address switches 6 and 7 down 8 5 and 4 up Make sure switch 3 is up off to allow the DRC8 IEEE to talk Set switch 1 down on to select CR LF as the delimiter orien tation NOTE The address switch is updated only on power up Connect the DRC8 IEEE to the 98034A IEEE interface of the 9845B Turn on the unit and enter the program below including line numbers by pressing the STORE 21 key after each line is entered Press the RUN key The display will then return the data from the instrument 10 DIMPS 5 TS 10 20 06 5 5 30 PRINT 40 PRINT 50 PRINT PANEL SPS 60 PRINT TEMPERATURE T 70 END Set the address switch to 6 by putting address switches 6 and 7 down 8 5 and 4 up Make sure switch 3 is up off to allow the DRC8 IEEE to talk Set switch l down on to select CR LF as the delimiter orientation NOTE The address switch is updated only on power up Connect the DRC8 IEEE to the 98034A IEEE interface of the 9825A Turn on the unit and enter the program below by pressing the STORE key after each line is typed Press the RUN key The printer will read the data from the instrument O dim PS 5 TS 10 1 red 706 PS TS 2 prt P 3 prt TS 4 end 3 9 3 5 9835 Set the address switch t
16. joo86000 4 15V 15V 15 59 C58 or gt 2 6 C 19 23 20 3 7 SE 4 1 215V 15V 15V U62 12 14 ef CH AC 5 C 21 R89 E D HPI6 DG R87 15V U51 7ALS175 74 U53 L 175 ME eec NOTES 1 There are additional IC sockets and components on the DRC 80 BCD L A option board They serve no functional purpose JE D JE C JE B JE A JE 47 J J LAHE SHORE CRVOTRORIKS amp Westerville Ohio geng DRC 80 BCD L A OPTION WA HI ie DTW SIZE DRWG NO E REVISION 169 81 07 22 pee amp 27404 lt 73481 7 8 2982 gt 9 36 NOTES 1 JA AND JB MATE TO MAIN BOARD CONNECTORS JG AND JH RESPECTIVELY 2 PINS 5 6 7 9 10 11 0102 ARE NC DS4 MSD DS3 DS2 Dei LSD 5082 7751 5082 7751 5082 7751 5082 7751 6 10 81 Westerville Ohio 43081 DISPLAY SCH BOA ARD EMATIC SIZE DRWG NO REVISION ml 5 4 Ze E 719 NNN 12V 5V rac C201 T THEM 4 3 18 1 10 57 D v lt C2 1 2 v 4 38 LE 29 10 53 32 10 54 1 3 26 10 52 J pit tit ee EE 20 10 50 ITIITI 1111B7 C C CC gt 2 10 47 74 4 13 37 10 46 36 10 45 the 31 10 44 30 10 43 25 102 4
17. range Please note that any sensor may be used with this option i e the customer is not restricted to the DRC Series sensors There are two computer options available each will output the displayed temperature and sensor selected from the SW 10A The Model 8022 is in a parallel BCD format while the Model 8024 is in the popular IEEE 488 format The DRC 80 Series is designed around an 3870 microprocessor and associ ated support circuits The DRC curve is stored in a PROM which can handle up to 32 break points The data consists of a table of temperature and voltage associated with each break point These straight line segments can generate the DRC curve to an accuracy of better than O 1 Kelvin over the entire tempera ture range 4 0 400 K 14 Major Assemblies Supplied The DRC 80 Series includes as standard equipment in addition to the digital thermometer controller the following A Operating and Servicing Manual B Two five Pin Plugs for Temperature Sensor Cables C One seven Pin Plug for Monitor of Sensor Output Voltage and the DRC8 L A option Model DT 500 Series silicon diodes are not supplied as part of the DRC 80 instrument Complete Specifications Accessory Equipment and Customs Options are listed in the front of the Manual 0781 0781 1 4 Ordering of Replacement or Additional Sensors Two different sensor configurations are available for use with the Model DRC 80 Series instruments These are the DT 500 DR
18. 211 5 Eee ell 8 S _____ el AE __ 4 ES 5 19 10 40 E F Hilli lt WEEN KEEN DEENEN m ss EEEEB e gt LT O 3211 R200 4 7K _____ ___________ 055 8 8 SWITCH DIP SWITCH CR200 e ps CUTLER HAMMER 5 2 591 8 R210 30 CR200 IN4148 MOTOROLA U202 pa U202 29 8 R21 218 AW 9 PLESSY BOX TYPE gt SE E E dama R201 C202 NOTES L C206 5 205 n 1 PORT DESIGNATION FOR MK3871 ARE C 204 Ai 40 47 50 57 203 n PIN8to GND C200 S n n n 3 JD IS A 24 PIN DIP SOCKET 1011 U210 213 MC3448AP MOTOROLA U204 0 811595 or 97N NATIONAL 611 U202 CD4049BN NATIONAL OR MOTOROLA 4 U205 U201 MC68488P MOTOROLA mua END 4 1 1200 MK3871 90071 MOSTEK 1311 BELDEN 9642 3 3 IEEE CABLE 1415 7 16 32 x 3 8 5 5 ON PORT 57 SELECTS TIMER 1 229966 4 DUST COVERS CLOCK Eben 55 266 1 BUS INTERFACE CONN KITS N T __________ 652633 4 REAR PANEL MOUNT HARDW ES 25 prey oye SELES 55579 Pc RECEPTACLE 3 1 AMP IEEE SOCKET 6 IF THERE ARE ADDITIONAL IC SOCKETS 21 JD 24PIN DIP SOCKET MATES W HEADER TO DRC JE AND COMPONTS ON THE DRC 80 JF N A 14 PIN DIP SOCKET MATES W HEADER TO NO FUNCTIONAL PURPOSE
19. 3 uf 100V 68 uf 100V 18 pf 500 st uf 100V CONNECTORS DESCRIPTION gt Pin Socket Sensor A 5 Pin Socket Sensor B 7 Pin Socket BCD Out IEEE Out Interface 10 Contact PC Mount Display Board MFR and PART NO Amphenol 126 218 mates with 126 217 Amphenol 126 218 mates with 126 217 Amphenol 126 198 mates with 126 195 Lake Shore PE Cryotronics Inc AMP MOD II 3 86018 5 mates to JG CIRCUIT DESIG JB JC JD JE JG JH JL CIRCUIT DESIG CR1 CR2 CR3 CR5 CR6 CR CR8 CRY CR10 051 052 053 054 0781 CONNECTORS DESCRIPTION 10 Contact PC Mount Display Board 14 Pin IC Socket SW 10 Input of switch position 16 Pin IC Socket IEEE Micro Interface 24 Contact Edge Card BCD L A Option 10 Contact PC Mount To Display Board 10 Contact PC Mount To Display Board 12 Contact PC Mount Power Transformer MFR and PART NO AMP MOD II 3 86018 5 mates to JH Cambion 703 5314 01 04 12 Cambion 703 5316 01 04 12 50 24B 10 MOD II 87228 5 mates to JA AMP MOD 87228 5 mate to JB AMP 350213 1 mates to 1 480 DIODES TYPE Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon 7 Segment LED Least significant LED 7 Segment LED 2nd Significant Digit 7 Segment LED 3rd Significant Digit 7 Segment LED Most Significant Digit 287 0 MFR and PART NO
20. 88 Model 8024 Component Layout Page iv LO 14 14 16 17 21 25 29 30 36 37 38 39 40 41 42 43 iii 0781 Specifications DRC 80 Thermometer Input Temperature Range 1 4 to 330K with standard DRC Sensor to 380K with other Sensors Sensor Silicon Diode order separately DT 500 DRC DT 500C U DRC 36 or any calibrated DT 500 Series Diode See below for proper response curve Sensor Input Dual sensor input 4 terminal input for each sensor Selection is via front panel pushbuttons Sensor Excitation 10 microampere current source Stabil ity 0 005 Sensor Response Curve Domestic US units require Sensor Curve 0 Export units require Sensor Curve E Sensor curves subject to change refer to manual for proper curve when reordering Sensors Curves to match existing Sen sors available on special request See also DRC Precision Option Input Resistance Greater than 1000 megohms Maximum Sensor Power Dissipation 25uW at 4 2K Temperature Readout Display 4 digit 11cm 0 43 LED shows temperature directly in Kelvin Resolution 0 1K Scale Expand increases resolution to 0 01K for temperatures below 30K 0 05K from 30K to 100K no increase in accuracy Accuracy 20 25 ambient 0 5 at4K and 77K 1 0K at 330K with standard Sensor See DRC Precision Option for accuracy with Lake Shore calibrated Sensor Temperature Coefficient 10 20 C and 25 45 ambient 0 01 Respon
21. C and the DT 500CU DRC 36 sensors Their description is included elsewhere in this manual All sensor configurations are available if the diode is calibrated and a special PROM is cut More than one curve presently exists which can be used with the DRC 80 Series instruments If additional sensors are ordered for use with your instrument you must be certain to order the correct curve so that your instrument will have its stated accuracy The proper curve may be determined in one of the following ways A Specify the sensor serial number that is currently being used with the instrument serial number is found on the end of the plastic box in which the sensor was received B Specify the serial number of your instrument Our records will indicate with which sensor the instrument is compatible C Remove the top of your instrument and observe the indicator on the PROM D The fourth way is to measure the diode voltage at 4 2K and give this value to Lake Shore Cryotronics Inc when re ordering sensors This Page Intentionally Left Blank 0781 SECTION II Installation 2 1 Introduction This section contains information and instructions necessary for the installation and shipping of the model DRC 80 Cryogenic Thermometer Included are initial inspection instructions power and grounding requirements install ation information and instructions for repackaging for shipment Led Initial Inspection This instrument was electricall
22. DO rS NO Ech 5984 42958 2932 2906 2880 2854 2828 69499 2643 2951 5458 5366 2226 2086 4946 4807 4667 4527 4387 4247 4108 3968 3618 3269 2919 2270 2220 1871 1521 1172 0909 0646 0119 9592 9066 8338 7610 6984 6359 2656 E 0781 DT 500DRC D Voltage Temperature Characteristic 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 1225 150 159 TEMP K PROM VOLTAGE k fa Hx GA n 4932 4219 3505 3006 2 50 7 2114 1720 1486 1308 41190 1116 1058 0970 0902 0850 0798 0746 0633 0520 0407 0287 0166 0046 99172 97690 96609 95927 93987 92647 91307 89966 88626 87286 85946 84606 83228 81850 80472 79094 2777110 11 DT 500DRC D Voltage Temperature Characteristic 0781 360 0 365 0 370 0 375 0 380 0 PROM VOLTAGE 76338 74961 73582 72170 70757 69344 07931 66518 65105 63693 62280 60867 59455 28080 56707 99334 53960 52649 451357 50026 48714 47403 46057 44711 43365 42019 40613 39208 37802 36397 34940 33482 22023 30568 29111 27654 226197 24739
23. Gnd LOGIC Note Gnd n refers to the signal ground return of the referenced contact EOI and REN return on con tact 24 3 9 2 Specific Operation of the DRC8 IEEE Interface Model 8024 The DRC 8 IEEE Model 8024 provides a digital output of temperature in Kelvin as well as the status of the front panel switches and SW 10 switch position Address and function selection are made via a switch package located on the rear panel of the DRC 80 see Figure 3 6 DRC IEEE Panel Layout Positions 4 8 of the switch are the address switches for the interface with 4 being the most significant bit and 8 being the least significant bit As an example with switches 5 6 and 7 ON or down and switches 4 and 8 OFF or up the address selected is 14 or E base 16 The DRC 80 IEEE Interface is a talker only The talk mode can be de selected by turning switch 3 ON or down Switch position 1 is used to select the order in which the output delimiters are put onto the IEEE bus The following table gives the deli miter orientation versus switch position 0382 Delimiter Order Switch 1 Position Delm 1 Delm 2 Up OFF LF CR Down ON CR LF The use of this switch allows the DRC8 IEEE to interface to controllers which accept both forms of delimiters to terminate input strings NOTE the address switches are updated on power up only The address and de limiter orientation is read only when the instrument is turned on Any change
24. able Parts List 0781 Page N FS Qn 13 13 13 13 13 15 18 18 19 20 21 22 22 22 23 23 24 26 27 27 27 27 27 28 28 28 28 31 9781 Reference Figure 1 1 Figure 2 1 Table 3 1 Figure 3 1 Figure 3 2 Table 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Table 3 3 Table 3 4 Figure 3 6 Figure 4 1 Table 5 1 Figure 5 1 Figure 6 1 Figure 6 2 Figure 6 3 Figure 6 4 Figure 6 5 Figure 6 6 Figure 6 7 Figure 6 8 Table of Illustrations Description Model DRC 80 Digital Cryogenic Thermometer Sensor Cable and Monitor Connections Entry Number Correlation DRC 80 Front Panel DRC 80 Rear Panel DT 500DRC D curve Voltage Temperature Characteristic Model DRC 80 shown with RM 3H Rack Mounting Hardware Model DRC 80 and SW 10A shown with Rack Mounting Hardware Model DRC 80 and SW 10A Rear View showing Rack Mounting Hardware and Umbilical Cord Connections SW 10A Connector Detail BCD Temperature Output Model 8022 DRC8O0 IEEE 488 Model 8024 Panel Layout Software Flow Diagram for DRC 80 Digital Thermometer DRC 80 Signals Associated with Fig 5 1 DRC 80 Signals DRC 80 Power Supply Schematic DRC 80 Main Board Schematic DRC 80 Main Board Component Layout DRC 80 Display Schematic DRC 80 BCD L A Model 8022 25 Schematic DRC 80 BCD L A Model 8022 25 Component Layout DRC 80 IEEE 488 Model 8024 Schematic DRC 80 IEEE 4
25. ature If a precision voltage source is used a breakpoint voltage should be dialed in and the display should be calibrated as above A breakpoint tempera ture above 40K should be used since the voltage sensitivity with tempera ture is lower at the higher temperatures 2 5 mV K than for temperatures below 30K 2 4 3 Adjustment of Output Buffer With a constant voltage fed into the instrument place a voltmeter between pins A amp B of connector J3 U9 is a buffer of input voltage and should have an output equal to input R4 is varied to obtain the proper buffered signal 5 4 4 DRC8 L A Option Model 8025 if present The output of the DRC8 L A Model 8025 is 10 mV K in the normal dis play mode In other words 100 0 K on the display corresponds to a 1 0000V output between pins C and D of monitor connector J3 To recali brate the option two adjustments need to be made With a low temperature on the display e g 22 0 k adjust the offset adjustment potentiometer R89 see Fig 6 DRC 80 BCD L A Layout until the output corresponds to 10 mV K Then take the display to a higher temperature e g 300 Adjustment of Gain Potentiometer R88 will bring the output to 10 nV K The procedure may need one more iteration that is go to the low tempera ture on the display adjust the offset then adjust the gain 255 Instrument Tests The first check to be made would be to check the input line fuse The type of fuse and line vo
26. cated that the fault is in the instrument after these tests the represen tative will provide shipping and labeling instructions for returning it When returning an instrument please attach a tag securely to the instrument itself not on the shipping carton clearly stating A Owner and Address B Instrument Model and Serial Number C Malfunction Symptoms D Description of External Connections and Cryostats If the original carton is available repack the instrument in a plastic bag place in carton using original spacers to protect protruding controls and close carton Seal lid with paper or nylon tape Affix mailing labels and FRAGILE warnings DO NOT GROUND SHIELD A RECOMMENDED SENSOR CABLE DO NOT GROUND SHIELD B ALTERNATE SENSOR CABLE GROUND 0 2 5V x B SENSOR VOLTAGE M 2 1OmV K a TEMPERATURE E _ GROUND IOmV K C MONITOR OUTPUT FIGURE 2 1 Sensor Cable and Monitor Connections 0781 6 This Page Intentionally Left Blank SECTION III Operating Instructions Jal Introduction Th s section contains a description of the operating controls and their adjustment under normal operating conditions and typical controller applications These instructions are based upon the instrument having been installed as outlined in Section II The diode polarity as shown in Figure 2 1 a in particular must be correct Ju Controls Indicators Connectors The operating controls indicators and
27. connectors on the DRC 80 instrument s front and rear panels are shown in Figures 3 1 and 3 2 The numbers with leaders to various controls in the figures are keyed to the entries in Table 3 1 Table 3 1 Entry Number Correlation NO KEY NAME FUNCTION 1 POWER A C line switch ON OFF Display serves as indicator light 2 Scale Expand With button out the display reads to 0 1K at all temperatures with button in detent position temperature reads to 0 01 below 30K 0 05 between 30K and 100K and to O 1K above 100K Sensor B Selects Sensor B 4 Sensor A Selects Sensor A 5 NO LABEL Digital temperature display located behind filter panel Sensor displayed depends on sensor selected LA 6 NO LABEL A C line cord 7 Fuse A C line fuse 8 Sensor A Sensor input lead terminals Pin A I Pin E V Pin B I Pin D V Pin H Shield 0781 9 Monitor Analog output of sensor voltage 0 2 5V Pin A and optional linear analog output of temperature O 4V Pin C Pin is ground for sensor voltage while Pin D is ground for L A output 10 Sensor B Same as Sensor A 11 Interface BCD input of set point output of temperature Also IEEE interface port 2 9 Temperature Readout The sensor s and heater should be installed following the sugges tions listed in the Installation and Application Notes for Cryogenic Sensors brochure in Section VIII Connect the sensor s to the instrument following the diagram in Figure 2
28. e SW 10A a specific curve or position can be called up through the use of 56 56 is actually four switches 4 position dip switch BO LSB of switch position is between pins 1 and 8 and B3 MSB is between pins 4 and 5 an example if the customer had precision options in positions 1 2 and 3 of the DRC 80 and wanted to use dip switches to call up the curves instead of the SW 10A umbilical he could insert a four station dip switch and turn on or off the desired position Switch S6 should not be used in conjunction with 16 pin header JC of the SW 10A The location for S6 is an 8 pin socket placed near JC see Fig 6 3 DRC 80 Component Layout 3 8 Remote Parallel BCD Output Option The BCD option consists of a 16 bit parallel output of temperature along with a scale expand bit to indicate decimal point and a 4 bit out put of switch position from the SW 10A Table 3 4 can be used for output line coding The BCD out is handled through connector J4 denoted on back panel as INTERFACE a 50 pin nector on the rear panel of the instrument Data latches internal to the instrument provide a 1 2 4 8 code using positive logic with standard TTL levels of 0 4 volts or less for low logic O and 2 4 volts or higher for the high or 1 state under full load conditions The drivers are sufficient to drive two standard loads 3 2 mA in the low state The sensor temperature output is externally gated through the use of an inte
29. equired for each sec tion will be denoted in that discussion 4 2 1 Power Supplies Please refer to Figure 6 1 Schematic 1 for the following dis cussion There are four different power supplies incorporated in the DRC 80 instrument The main power transformer 1 has split pri maries for 115 or 230 volt AC operation The slide switch 52 selects the proper line voltage EU 0781 The first secondary is output through leads 1 and 3 This secondary is rectified by CR1 and a floating 15 volt supply is obtained through C1 65 and the positive 15 volt regulator U1 This supply is used to power the constant current source for the diode The second secondary through leads 2 4 and 6 is a full wave bridge rectified by CR2 5 A 15 volt supply is generated by C2 C6 and a positive 15 volt regulator U2 negative 15 volt supply is gener ated by C3 C7 and voltage regulator U3 Both these supplies are used in the A D converter the buffer section and the L A option The third secondary is through leads 8 10 and 12 and is full wave rectified by CR6 7 The five volt supply that is used by the TTL 1C s is formed by C4 C8 and a 5 volt positive voltage regulator U4 4 2 2 Precision Constant Current Source and Front Panel Switching A 100A floating constant current source is used to excite either Sensor A or B depending on the switch position chosen by the front panel switches S5 Sensor A or S4 Sensor B A precision ref
30. erence voltage is generated by an internally stabil ized precision voltage reference U5 and resistor Ri which determines the bias current for the zener reference Resistor R6 has a nominal 499K value so that when the voltage picked off the stable reference is close to 4 99V the output current determined by the operational amplifier U6 the output FET U7 will be exactly 10uA with a compliance voltage greater than 10V The 109A current is directed to Sensor or Sensor B by the switch S5 Switch 4 directs the positive sensor voltage of Sensor A or B to the A D converter pair Note that both the Sensor A and Sensor B low voltage terminals are tied together to analog ground Therefore the I r turn of the current source will be slightly below ground by a few millivolts depending on lead resistance Since 55 and 54 are interlock ing switches the switch 54 is used to tell the microprocessor which sensor has been selected This information is important to the micro processor only if a calibrated sensor is present or if a SW 10A ten position switch option is present in Sensor position B Switch 53 indicates to the microprocessor whether or not scale expand below 100K is desired switch S1 is the ON OFF switch Power ON is indicated by a lighted display board 4 2 3 A D Converter and Microprocessor System The analog to digital convertor consists of a high input impedance precision 45 digit I C pair 8052A 7103A U12 and U10 tha
31. in Style L half rack package Model RM 3H Rack mounting hardware to mount either one or two Style L half rack unit s in standard 3 rack space DRC Precision Option Custom programmed read only memory for DRC instruments which improves specified accuracy to 0 1K or better over a given calibration range Any DT 500 Series Silicon Diode Sensor can be utilized Requires that an appropriate calibration be purchased for the Sensor Specify Sensorinput position A or Bor 1 10 on SW 10A to assure proper location of calibration within PROM First calibration stored Subsequent calibrations stored in same PROM Model DT 500 DRC Sensor Silicon Diode Temperature Sensor for DRC 80 1 5mm diameter x 4 1mm long Specify response curve Model DT 500CU DRC 36 Silicon Diode Temperature Sensor for DRC 80 8mm diameter x 3 3mm thick with mounting hole Specify response curve SS LakeShoreCryotronics Inc CRYOGRENIC THERMOMETER MODEL QAO UR Digital Oryogenic Thermometer ep 0781 SECTION I General Information 1 1 Introduction The following is a description of the DRC 80 Cryogenic Digital Thermometer The DRC 80 Series of instruments is designed to be used with the Model DT 500 DRC and DT 500CU DRC 36 silicon diode sensors manufactured by Lake Shore Cryotronics Inc Several different diode sensor curves are available for use with this instrument When ordering replacement sensors care must be taken to assure that the co
32. in the address switch while the instrument is on will be ignored The DRC8 IEEE transmits and receives all characters in ASCII The cable connector meets IEEE 488 1978 standards and is polarized for proper cable insertion In the talker mode the interface outputs switch settings front panel settings and display temperature The data is output in the form of two string variables After each of the variables is output delimiters DELM 1 and DELM 2 are transmitted After the second variable the last delimiter has the EOI line set for end of transmission NOTE In programming for an input from the DRC8 IEEE interface two string variables must be used or read into the computer or the inter face will hang up waiting to output all of the data In outputting data to an array the array must have enough elements to allow the input of both variables from the DRC8 IEEE interface in this case the number of elements is 13 Since there are two sets of delimiters output and most computers use these delimiters to terminate string variables the need for two string variables arises An example of a transmission is as follows Function Format for Data Format Limits X Front Panel XX DELMI DELM2 0 9 A F Temperature XXXX XX DELMI DELM2 numberics only The two front panel characters are output in a packed format with individual bits representing a piece of data The front panel indicators are denoted as follows 0382 20 0382 Bit
33. ion IEEE Standard Digital Inter face for Programmable Instrumentation All instruments on the interface bus must be able to perform the interface functions of TALKER LISTENER or CONTROLLER A TALKER transmits data onto the bus to other devices A LISTENER receives data from other devices through the bus Some devices perform both functions The CONTROLLER designates to the devices on the bus which function to perform The IEEE works on a party line basis with all devices on the bus connected in parallel All the active circuitry of the bus is contained within the individual devices with the cable connecting all the devices in parallel to allow the transfer of data between all devices on the bus There are 16 signal lines contained on the bus and consist of A 8 Data Lines B 3 Byte Transfer Control Lines C 5 General Interface Management Lines The data lines consist of 8 signal lines that carry data in a bit parallel byte serial format These lines carry universal commands addresses program data measurement data and status to all the devices on the bus The controller designates the functions of the units on the bus by setting the ATN line low true and sending talk or listen address es on the DATA lines When the ATN line is low all devices listen to the DATA lines When the ATN line goes high false then the devices address ed to send or receive data perform their functions while all others ignore the DATA lines Transfe
34. ion of 01 below 30K and 0 05K between 30K and 100K The temperature data is output in a bit parallel digit serial form and is latched into the display board 4 2 5 Digital Display Board The display board receives its data in a bit parallel digit serial form The information is latched into the display decoder driver U101 which drives the display digits DS1 4 Control of the decimal point is carried out by the BCD decimal decoder driver U102 This driver receives its information directly from the microprocessor 26 This Page Intentionally Left Blank SECTION V Calibration and Troubleshooting Died Introduction This section contains the instructions for calibrating and trouble shooting the DRC 80 instrument 232 Test Equipment A high input impedance digital voltmeter and oscilloscope and a precision resistor connected to simulate the diode wired according to Figure 2 1 b are normally sufficient to test and calibrate the DRC 80 instrument a d General Remarks On installation one of the major problems is an improperly connect ed temperature sensing diode It is advised that other portions of the cryogenic system be tested before the instrument is troubleshooted Some checks that could be made are 1 Open or shorted sensor leads especially in an area of frequent disassembly 2 Leakage paths between heater and sensor leads that induce electrical feedback in addition to thermal feedback If the malfuncti
35. ltage are shown on the rear panel of the instrument If the input line voltage and sensor input voltage have been checked the following sequence should be followed 1 Check all power supplies for proper operation The voltages can be noted on Fig 6 3 DRC 80 Parts Layout 2 Check for the waveforms at the following pins and refer to Fig 5 1 for waveforms 28 0781 Ge 0781 Signal paths should also be checked If signals are present at source components and not at destination components a printed circuit problem requiring a repair of the printed circuit foil may be required Continuity checks between points will turn up any unwanted open circuits in signal paths If the signals at the component pins outlined in Table 5 1 are present and a problem still exists a factory representative should be contacted Table 5 1 DRC 80 Signals Associated with Figure 5 1 Signal Function Wave Form a Pin 12 of 010 Clock signal of A D converter The or frequency should be about 50K Hz i Pin 3 of Ull If not present replace 011 Also 3 check R12 R11 and Cll 0 _ 20 20 eer b Pin 14 of U12 Integrated signal of A D to deter mine the count period The period should be about 35 seconds If not present check 010 and Uli 0 5 Volts Input 2 5 Volts Input c Pin 7 of 110 This is a D C level that is the reference voltage for the inte grator The value should be between 1 4 and 1 8 volts If not present
36. o 6 by putting address switches 6 7 down 8 5 4 up Make sure switch 3 is up off to allow the DRC8 IEEE to talk Set switch 1 down on to select CR LF as the delimiter orientation NOTE The address switch is updated only on power up Connect the DRC8 IEEE to the 98034A interface of the HP 35A Turn the unit and enter the program below by pressing the STORE key after each line is typed Press the RUN key The display will return the data from the instrument 10 706 5 5 20 PRINT 30 PRINT 40 PRINT PANEL PS 50 PRINT TEMPERATURE T 60 END 0382 21 3 9 4 Field Installation of DRC IEEE Model 8024 DRCS8 IEEE Model 8024 is easily field installed as follows 1 Remove instrument cover 2 Remove blank plate from Interface opening J4 3 Plug 24 pin umbilical into DRC 80 board connector see Fig 6 3 DRC 80 Component Layout 4 Place Model 8024 board in the unit and install with screws Component side up 5 Replace instrument cover Cable Connection Select switch Open 12345678 Figure 3 6 DRC8O IEEE Panel Layout 0382 21 This Page Intentionally Left Blank 0781 SECTION IV Theory of Operation AT Introduction The Lake Shore DRC 80 is the ideal Cryogenic Thermometer for lab or system use Its features options and accessories enable it to handle routine measurements or complex multi point monitoring assignments with equal ease
37. on points toward the instrument more detailed tests should be made 5 4 Instrument Calibration The DRC 80 has been factory calibrated If a recalibration is need ed the following procedure should be followed Please refer to the component layout for the DRC 80 Figure 6 3 for the following discussion 5 4 1 Current Source A precision resistor of not less than 01 tolerance should be connected across pins A and B Figure 2 1 of the A Sensor socket A high input impedance voltmeter connected across the precision resistor should measure a voltage equal to 10 microamperes times the value of the resistor For example a 100K ohm 01 resistor should read 1 0000 volts within 100 pvolts If recalibration is needed the voltage across the 100K resistor can be adjusted by varying resistor R3 0781 uc 5 4 2 A D Converter To adjust the A D converter a voltage needs to be applied across pins E and D Figure 2 1 of the display sensor connector A variable 200K resistor hooked up as in Fig 2 1 a or precision voltage source in place of the diode are ideal ways to generate this voltage If a re sistor is used it should be varied until one of the breakpoint voltages indicated in the Voltage Temperature Characteristic Table is generated A high impedance voltmeter must be used for this adjustment After an appropriate voltage is obtained the display should be calibrated by ad justing trimpot R16 until the display reads the correct temper
38. or fro R21 and C21 if needed The MPU has 4 8 bit bi directional ports used for communication to and from the pro cessor Two of these ports Port O and 5 are used for internal control of the instrument A D input BCD temperature output to BCD L A option and display and internal housekeeping The remaining two ports Port 1 and 4 are used for option access IEEE 488 4 2 4 Software DRC 980 Cryogenic Thermometer Figure 4 1 is a flow chart of the major steps in the cryogenic thermometer program When the instrument is turned on the program does a power ON reset and starts the software program at the beginning At this point the program initializes internal registers to be used in the program The program first checks for an A D converter overrange and then inputs multiplexed A D information When the A D tells it there is fresh data ready the program loops until the A D information is ready the program then verifies that no illegal characters are present and stores the reading The program then inputs display sensor information There is one standard curve for the instrument and there are a maximum of twelve additional curves There can be a calibrated curve for Sensor A B and ten different switch positions generated by the SW 10A The program through the use of some internal identifiers determines the proper curve to be used Once the curve is determined the proper Voltage Temperature Break 0781 22 6 0781 FIGURE 4 1
39. ows 1 Remove instrument cover 2 Insert the model 8022 25 option board into instrument JE connector the instrument has its edge card connector configured such that the option board can only be inserted in one way 3 Take 50 pin ribbon connector with mounting plate attached and place it in Interface opening J4 after any existing plate is removed Note Ribbon cable is only present for Model 8022 option 4 Connect black or green and white wires of option board to 7 pin rear panel connector J3 White goes to pin C and black or green goes to pin D 5 Replace instrument cover Standard DT 500DRC and DT 500CU DRC 36 Curves The standard DT 500 DRC and DT 500CU DRC 36 curve is explained in Section 3 3 The Tables include a list of PROM sensor voltages and break points used in the linearization of the DRC curve to arrive at the correct temperature readout 3 6 Rack Mounting the DRC 80 The DRC 80 cryogenic thermometer can be rack mounted with the RM 3H rack mounting hardware as shown in Figure 3 3 This hardware kit also allows the mounting of two style L half rack units as shown in Figures 3 4 and 3 5 3 7 The 10 Sensor Selector Switch The 10 Sensor Selector Switch includes an umbilical which ties to the DRC 80 main printed circuit board via a 16 pin ribbon cable header which plugs into internal socket JC see Figure 6 3 DRC 80 Component x13 0781 ee ee eer ShoreCryat
40. ptacle grounds the instrument 2 29 Installation The DRC 80 Thermometer is all solid state and does not generate signifi cant heat It may therefore be rack mounted in close proximity to other equip ment in dead air spaces The heat from such adjacent equipment should not subject the thermometer to an ambient temperature in excess of 50 C 122 F 0781 As with any precision instrument it should not be subjected to the shock and vibrations which usually accompany high vacuum pumping systems The recommended cable diagrams for the sensor diodes are shown in Figure 2 1 a The use of a four wire diode connection is highly recommended to avoid introducing lead IR drops which will occur if the alternate two lead sensor cable connection is used For example for a two lead connection every 25 ohms of cable resistance corresponds to a 1 K error above 30 Kelvin The alternate wiring scheme shown in Figure 2 1 b may be used for the diode in less critical applications where lead resistance be kept small The indica ted shielding connections are the recommended standard practice to avoid ground loops 2 6 Repackaging for Shipment Before returning an instrument to the factory should repair be neces sary please discuss the malfunction with a factory representative He may be able to suggest several field tests which will preclude returning a satisfac tory instrument to the factory when the malfunction is elsewhere If it is indi
41. r of the information on the data lines is accomplished through the use of three signal lines DAV Data Valid NRFD Not Ready For Data and NDAC Not Data Accepted These signals operate in an interlocking handshake mode The two signal lines NRFD and NDAC are each connected in a logical AND to all devices connected to the bus The DAV is sent by the talker and received by listeners while the NRFD and NDAC are sent by listen ers back to the talker The General Interface Management Lines manage the bus and control the orderly flow of commands on the bus The IFC Interface Clear message 18 basically clears the interface to a known state appropriate to the device being addressed SRQ Service Request is used by a device to indicate the need for attention or service and to request an interruption of data flow REN Remote Enable is used to select between two sources of device data as an example front panel or rear panel controls on a measurement device EOL End or Identify indicates the end of a multiple byte transfer sequence or along with the ATN line executes a polling sequence The following table shows cable connector contact wiring for the IEEE 488 bus Contact Signal Line Cont ct Signal Line 1 DIOL 13 DIO5 2 DIO2 14 106 3 DIO3 15 DIO7 4 DIOA 16 DIOS 5 EOI 24 17 REN 24 6 DAV 18 Gnd 6 7 NRFD 19 Gnd 7 8 NDAC 20 Gnd 8 9 IFC 21 Gnd 9 10 SRO 22 Gnd 10 11 23 11 12 SHIELD 24
42. ranics Ine THERMOMETER MODEL GRE 88 POWER eoi FIGURE 3 3 Model DRC 80 shown with RM 3H Rack Mounting Hardware Lake Shore Cyotenics he SENSOR BELECTOR MODEL SW 104 SERA PONER 7277 7 TO HOKBESTOR FIGURE 3 5 Model DRC 80 and SW 10A Rear View showing RM 3H Rack Mounting and Umbilical Cord Connections awas cu Sore SaaS 4 2 2 zs po 2 D A 4i 4 Hardware 14 0781 Layout and a cable to connect the selected sensor leads to the DRC 80 Sensor plug B is Key 10 of Figure 3 2 SW 10A is supplied with an 18 cable which is shielded and has male 5 pin amphenol connectors at each end see Figure 3 5 SW 10A Option This cable connects between J11 of the SW 10A and the B sensor plug of the DRC 80 Sensors are connected to the SW 10A via printed circuit edge 710 36 pin edge card connector and hood has been supplied with the SW 10A Connectors to this edge J10 are given in Table 3 3 The hood mechanical assembly is given in Figure 6 9 SW 10A Hood Assembly Provisions have been made in the DRC 80 for setting the switch posi tion which the instrument will see S6 Since the software of the DRC 80 allows for calibrated curves to be programmed into the 10 positions of th
43. rnally generated data valid pulse E Table 3 3 SW 10A CONNECTOR DETAIL Shield All 11 I V V 14 V I V V I V V I V Va I V Ve I V V I V 1 V in I E lt C QO o Z DG O G vn IJ E J O LA JG ON ON Ohn Cn Cn GA CO CO n2 N MPH gt e O O O e 0781 0781 Table 3 4 BCD TEMPERATURE OUTPUT MODEL DRC SERIES REMOTE OUTPUT 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 L 2 5 7 91113221517 19 21 23 25 27 29 31 33 35 37 39 41 43 45 4T 49 BCD TEMPERATURE OUTPUT 800 80 400 40 200 20 100 10 80 8 40 4 20 2 10 1 8 8 12 14 16 18 20 22 24 26 28 30 22 BCD TEMPERATURE OUTPUT Data Valid 34 Ground Trend Bit 36 SW B2 1 01 O 24 SW B3 38 Not used 40 42 44 46 48 Not used 50 Not used oW BO SW B1 di 0781 3 9 IEEE Interface Option The IEEE interface option available for the DRC 80 fully complies with the IEEE standard 488 1978 and incorporates the functional electrical and mechanical specifications of the standard 3 9 1 General IEEE Specifications and Operation The following discussion covers the general operation of the IEEE 488 interface For a more detailed description of signal level and interaction refer to the IEEE Std 488 1978 publicat
44. rrect sensor curve is specified Multiple curves are needed so that Lake Shore can assure the customer that replacement sensors will be available at any time in the future For details please see Section 1 4 12 Description DRC 80 Series is comprised of completely self contained units providing direct digital readout in Kelvin temperature units and for the controllers temperature control by direct analog comparison between the sensor voltage and an analog equivalent of the digital temperature set point The DRC 80 displays temperature to O 1 Kelvin over its operating range of 1 400 Kelvin for normal operation In the scale expand mode the resolution is 0 01 Kelvin below 30 Kelvin and 0 05 Kelvin from 30K to 100 Kelvin The specified range of operation is 4 0 to 380K utilizing standard DRC series sensors which have been pre selected to provide uniform character istics over this range These sensors conform to the standard table see Table 3 3 to 0 5 or better below 77K and better than 1 Kelvin above 77K The instrument however displays down to although accuracy is only speci fied above 4K Pre selection allows the DRC 80 Series to be used with the DT 500 DRC and DT 500CU DRC 36 sensors without adjustments of any kind Since the standard sensors are interchangeable the instruments may be used to read out any number of sensors with equal accuracy when selected through an appro priate switch such as the SW 10A The DRC 80 ha
45. s dual sensor inputs Sensor selection is made via front panel pushbuttons As a standard feature all units are equipped with buffered analog output of the display sensor voltage This allows the instrument user the ability to record the display sensor voltage versus time or to use a digital voltmeter to measure the display sensor voltage directly Since this output is buffered high input impedance recorder or voltmeter is not required If possible temperatures above 330K should be avoided with DRC Series sensors since these sensors may slightly shift their values below 20K if heated above 330K If the sensor is calibrated by the user or by Lake Shore Cryotronics Inc temperature may be determined to approximately 10 Five options are available with the DRC 80 Series of instruments One option is an analog signal which is proportional to temperature Model 8025 and has a sensitivity of 10 mV K A second option is a ten position switch SW 10A for multiple sensor readout This switch is a separate half rack box which plugs into the Sensor B posit on of the DRC 80 The sensor selected is also identified via digi tal interface of the DRC 80 if present Another option is a custom cut PROM DRC Precision Option which corres ponds to the calibration curve of the customer s DT 500 Series sensor A combination of a calibration and custom cut PROM will increase display accur acy to better than 1 Kelvin over the calibrated
46. se Time Less than 1 second to rated accuracy General Monitor Output Buffered output of Display Sensor voltage additional outputs listed below as options Dimensions Weight 216mm wide x 102mm high x 330mm deep 8 5 inx4 in x 13 Style L half rack package Net weight 3 6 kg 7 9 Ibs Power 90 110 105 125 or 210 250VAC switch selected 50 or 60Hz Accessories Supplied Mating connectors for sensor inputs and monitor instruction manual FIGURE 1 1 Model DRC 80 Options and Accessories Available Model 8022 Parallel BCD output for DRC 80 TTL compat ible Provides BCD output of temperature in Kelvin and Sensor selected either from front panel or optional SW 10A Model 8024 IEEE 488 output for DRC 80 Provides digital output of temperature in Kelvin and Sensor selected either from front panel or optional SW 10A Model 8025 Analog output proportional to Kelvintempera ture for use with recorders or other readouts 10mV K at 10 ohm output resistance field installable Model 8022 25 Combination of 8022 BCD output and 8025 Analog output installed in same unit Model SW 10A 10 Sensor Selector Switch for use with DRC Thermometer or Controller Push button selection of any one of up to 10 sensors Connects to Sensor B position of instrument Sensor selected is also identified via 8022 or 8024 digital interfaces Dimensions 216mm wide x 102mm high x 330mm deep 8 in x 4 in x 13
47. splay sensor no SW 10A input and a display of 24 06 K would look like 80 LF CR 0024 06 LF CR EOI SET ON FINAL CR 0382 3 9 3 Sample Programming This section contains some sample programming for the DRC8 IEEE option 3 9 3 1 Commodore Pet CBM 2001 Set the address switch to 6 by putting address switches 6 and 7 down 8 5 and 4 up Make sure switch 3 is up off to allow the DRC8 IEEE to talk Set switch 1 up off to select LF CR as the delimiter orientation NOTE The address switch is updated only on power up Con the CBM IEEE cable to the DRC8 IEEE interface Turn on the PET and enter the program below including line numbers by pressing the RETURN key after every line After entering the program type RUN and press the RETURN key The display will then return the data from the instrument 10 OPEN2 6 20 INPUT 2 PS TS 30 CLOSE2 40 PRINT 50 PRINT 60 70 PRINT TEMPERATURE T 80 END 3 9 3 2 HP 85 Set the address switch to 6 by putting address switches 6 and 7 down 8 5 and 4 up Make sure switch 3 is up off to allow the DRC8 IEEE to talk Set switch 1 down on to select CR LF as the delimiter orien tation NOTE The address switch is updated only on power up Connect the DRC8 IEEE to the IEEE interface of the HP 85 Turn on the unit and enter the program below including line numbers by pressing the END LINE key after every line Press the RUN key The
48. t produces a BCD output that is accurate to 1 count over its entire 40 000 count mc range The 7103A U10 runs on a 50K Hz clock cycle generated by a 7555 clock U11 and its associated components R11 R12 and C11 This clock frequency allows for one reading every 0 8 seconds The digital output signal is in a bit parallel byte serial form The A D converter output is multiplexed by U14 and U15 and input to the microprocessor In addition to the A D voltage information the microprocessor inputs the sensor selected scale expand switch position and in the case of the SW 10A the position selected The microprocessor outputs temper ature information in BCD form to the display as well as to the options BCD or IEEE if present If a ten position switch is also present the sensor position selected is also output to the option BCD or IEEE The microprocessor system used in the DRC 80 is a 38P70 which utilizes a piggy back memory architecture A 3870up was originally a mask memory part with the user tied to one program form when the part was fabricated The piggy back variation of the part allows for variable memory space between 8K and 64K of PROM to be placed on the top of the up This allows all lines that were used for addresses and data to be used for Input Output The microprocessor unit MPU has an internal RAM scratchpad memory used for programming The unit uses an internally generated clock which is derived from the resist
49. y and mechanically inspected prior to shipment It should be free from mechanical damages and in perfect working order upon receipt To confirm this the instrument should be inspected visual ly for obvious damage upon receipt and tested electrically by use to detect any concealed damage Be sure to inventory all components supplied before dis carding any shipping materials If there is damage to the instrument in tran sit be sure to file appropriate claims with the carrier and or insurance company Please advise the company of such filings In case of parts short ages please advise the company The standard Lake Shore Cryotronics warranty is given on the title page 243 Power Requirements Before connecting the power cable to line voltage insure that the instru ment is of the proper line voltage and fused accordingly The line voltage and fuse are shown on the rear panel of the instrument The line voltage can be changed by switching line voltage selector switch S2 Figure 6 3 DRC 80 Component Layout located on the main printed circuit board of the unit Nominal permissible line voltage fluctuation is 10 at 50 to 60 Hz 2 4 Grounding Requirements To protect operating personnel the National Electrical Manufacturer s Association NEMA recommends and some local codes require instrument panels and cabinets to be grounded This instrument is equipped with a three conductor power cable which when plugged into an appropriate rece
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