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Model DRC-91C - Lake Shore Cryotronics, Inc.

1. NECI UR AND ARE OPEN COLLECTOR INVERTERS 7486 P CER PIN 14 I 5 6 PIN 7 18 GND LAKE SHORE CRYOTRONICS INC MODEL 8229 SCANNER OPTION CARD _ me 16 e7 SIZE NO 27 26 1 525 86 91 0 SHEET i OF 1 Figure 8 229 1 _ 8229 Scanner Conversion Option APPENDIX A Standard Diode Voltage Temperature Characteristics D CURVE El CURVE DT 470 CURVE 10 LEE d VOLTAGE BP VOLTAGE BP VOLTAGE 2 5984 220094 1 69808 2 5958 2 6567 1 69674 2 5932 2 6542 1 69521 2 5906 2 6518 1 69355 2 5880 2 6494 1 69177 2 5854 2 6470 1 68987 30 2 5828 29 2 6446 28 1 68912 2 5735 2 6355 1 68352 2 5643 2 6265 1 67880 2 5551 2 6175 1 67376 2 5458 2 6084 1 66845 29 2 5366 28 2 5994 1 66292 2 5226 2 5868 1 65721 2 5086 2 5742 1 65134 2 4946 2 5616 1 64529 2 5490 1 64112 27 2 5364 1 63263 2 5221 1 62602 2 5077 1 61920 2 4934 1 61220 2 4791 1 60506 2 4648 1 59782 2 4290 2 3932 1 56027 2 3574 1 54097 2 3216 1 52166 2 2858 1 50272 2 2500 1 48443 2 2142 1 46700 26 2 1784 26 1 44850 2422516 1 43488 2 0646 2 1247 1 42013 2 0119 2 0708 1 39287 1 9592 2 0170 25 1 36687 24 1 9066 25 1 9632 1 34530 1 8338 1 9011 1 32412 1 7
2. 37 341125 HEATER ap ee 4 3 11 6 The HEATER POWER RANGE s s 3 11 3 12 LOCAL REMOTE BLOCK o9 46854 6444 4 e gt 3 11 2 1221 3 12 2 a 3 11 REAR PANEL DESCRIPTION 3 12 REMOTE SENSOR ID 4 i s s e d a X UE 37 l3 3 14 HEATER CURRENT LIMIT amp a a 3 13 SECTION IV REMOTE OPERATION 4 zx 1 4 88 INTERFACE gt a 4 T 1 4 2 GENERAL IEEE SPECIFICATIONS AND OPERATION Sm oe de c 4 1 4 3 INTERFACE CAPABILITIES gt 5 4 2 12 87 TABLE OF CONTENTS Cont d 4 4 DRC 91C IEEE 488 ADDRESS SWITCH 4 3 4 4 1 Terminating Characters delimiters 4 3 4 4 2 Talker and or Listener Configuration 4 3 4 4 3 The IEEE 488 INTERFACE bus address 4 5 4 5 IEEE 488 BUS COMMANDS 4 5 4 5 1 Uniline Commands 4 5 4 5 2 Universal Commands E 4 5 4 5 3 Addressed Commands 4 5 4 5 4 Unaddress Commands OPI 4 6 4 5 5 Device Dependent Commands 4 6 4 5 6 Talker and Listener Status 4 6 4 6 PROGRAMMING INSTRUCTIONS 4 7 4 6 1 Comm
3. D3 44 2 pe 599 14ANL 21 1 CARD Lg 415 ______ _ 54 m JL 121 ome MZ lm RS8 CS IEEE U16 RESET e 51 1 A DBIN 2 wa ADS GUS Ae eee eee Re e MC 26 ATN p M E RI 7 IFC 3 IFC Al 519 2 SRO AB 9 21 EO AD 659 52 abs 1518 24 ADS 619 56 619 58 AD3 1519 38 5188 32 Abi 619 34 LEITET 619 98 nee 2 pego quem a Int AA IB 58 U4gb EAS neu MERE E MM 82C55A 5 3 pe ae AL A AE o X Gc ABO E 9 9 15 o pata EE 14 18 amp DaTA 9 0874 37 i AAA PAT ce NEP iR Ao AE Tee E 5 ALAS D A S RA ___ 111 1 tp cc roue RTM ____ Lx ee ee 5556 06 8 21 rope re a ET ______11 Ui do dn 1 1112 EST i 14
4. i SLOT 4 hate XU20 XU37 XU39 XU23 U32 C32 XU19 RN7 xu I _ 2 000000000 z o x gt 11 1 TX1 XU26 Figure 91C 1a Component Layout DRC 91C Main Board es em ae PARTS LIST DRC 91C MAIN BOARD ITEM LSCI Part NO Number 1a Description D MFR PART PART NO _ 101 275 CAP ELECT 9500MF 15V 35188BA952U015AMA1 101 225 CAP ELECT 470MF 35 ECEAIVVATIS 101 238 101 034 CAP ELECT 2100MF 75V CAP PP 1MF 100V 5186 2120075 1 MPP2X 1 0 100 10 C40 42 CR2 6 CR7 10 102 008 102 003 BRIDGE RECTIFIER DIODE RECTIFIER WO2M MR501 d AJ ow 26 29 CR12 13 102 001 DIODE RECTIFIER 1N4006 CR19 102 058 DIODE ZENER 24V 1 4749 CR20 102 053 DIODE 2ENER 5 1V 1N751A 106 310 CONNECTOR IEEE 57 92245 12 106 412 CONNECTOR REMOTE ID 609 1602M 106 146 CONNECTOR TX1 TO MB 2630 09 74 1091 106 419 CONNECTOR DB TO MB 5592 6002 106 139 106 143 106 129 CONNECTOR TX2 TO MB CONNECTOR BP TO MB CONNECTOR POSTS 2650 09 74 1041 2630 09 74 1061 TSW 120 04 06 105 302 105 304 DRY
5. 6 8 Te 3 LAKE SHORE CRYOTRONICS INC up L 157 B ees OA CHANNEL CURRENT SOURCE SUPPLY DRC 91C MAINBOARD oF oT _ INPUT POHER SUPPLY SIM HS H6 89 14 97 DHG NO 444 86 91 AC POHER BUSS aoe E Em SHEET 1 OF 7 Figure 91C 1b Schematic DRC 9 1C Main Board 1 Input Power Supply gt CR13 144994 624 25 iere E BRN HHT 1 3 gt BLK WHT Ja WHT E TPE es 0o 9 gt 16 GRN GRN 2 1 6 gt 4 15 E 52 gt 16 U13 MOUNTED ON HEAT SINK ASSEMBLY 2 AE ABOVE MAINBOARD mE DRC 31C MAINBOARD DUTPUT POWER SUPPLY 89 11 87 09 11 67 size SIZE DWG NO 458 86 01 15 47 59 B oe US 8 C 81 SHEET 2 OF 7 Figure 91C 1c Schematic DRC 91C Main Board 2 Output Power Supply A m 5 NOTE 1 048 IS 7406 PIN 14 GND D PIN 7 WITH C amp 1 ACROSS 7 AND 14 D A a 18 18 17 8 0 z 7194540 amp De 16 64 94 4 24
6. E BEER ER 8 1 PLACE WHEN esis 16 REQUIRED qe LINT FOR ADDED a ue mee GND Model DRC 91C Section VI SECTION VI ACCESSORIES INPUT CARDS AND OPTIONS TABLE OF CONTENTS MODEL OR PART NUMBER DESCRIPTION PAGE ACCESSORIES RM 3F Rack Mounting Kit E e E 6 2 8072 IEEE 488 Interface Cable 6 2 8271 04 Scanner Sensor Cable for 8229 6 2 8271 21 Sensor Heater Cable i xo x xe ww 6 2 8271 22 Sensor Heater Output Cable 6 2 HTR 50 50 ohm Cartridge Heater 50 W 6 3 HTR 25 25 ohm Cartridge Heater 25 W 6 3 INPUT CARDS Old Input Card Dip Switch Definitions 6 3 8210 8211 8219 P2 8219 P3 8219 R1 9210 Diode Input Card L 9210 1 9215 Capacitance Input Card 9215 1 9220 User configurable Input Card 9220 1 9305 Thermocouple Input 9305 1 9317C Ultra low 0 3K Resistance Card 2 931 C 1 9318C Germanium Carbon Glass Resistance Card 9318C 1 OPTIONS 8223 RS 232C Interface Option 8223 1 8225 Analog Output Option 8225 1 8229 Scanner Conversion Option amp 8229 1 9126 High Resolution Set Point Option 9126 1 COPYRIGHT 12 87 LSCI 6 1 Section VI 6 1 INTRODUCTION This section contains information concerning the Accessories Input Cards and Opti
7. or C102 C5 CgC7 8 9 N1N5 1 12 NAN5 Ne C135 32 characters plus up to 2 terminators where C4C5 is the Display Sensor AO A1 A2 A3 A4 or BO C4C4 is the Control Sensor AO Al 2 A4 or BO Cs is the Set Point Units K C F V N or R C6C7 is the Remote Position 00 through 1F ID 00 through FF Curve Number 00 through 31 Input Resolution O xxx to 4 x xxxx Input Units K C F V N or R 4 9 THE CONTROL COMMANDS 4 9 1 The Set Point Value The S Command The set point is sent from the controller to the DRC 91C in a free field format of which examples are given in Table 4 9 Note that the sign only has to be present if negative celsius fahrenheit settings are desired Although the limits on the input range above the values possible for the various sen sors the set point is limited by the input card present as shown in the table Note that the temper ature limit can be different for the DT 470 depending on whether curve number 02 324 9K or curve number 04 474 9K has been selected If a number above the limitation for the card is entered the set point is set to the upper temperature limit Also note that an S sent by itself to the 91C sets the set point to O kelvin or its equivalent in the units chosen which will result in shutting down the heater 4 13 Section IV output stage of the temperature controller N
8. 4 2 is cil Trs DIG Interface Option _ Figure 8223 1 Model DRC 91C 93C Model 8225 Analog Output MODEL 8225 ANALOG OUTPUT 8225 1 INTRODUCTION This section contains information pertaining to the Model 8225 Analoq Output for the 91 93 Temperature Controller Included is a description specifications installation operation and main tenance information 8225 2 DESCRIPTION The 8225 Analog Output is designed to be installed in DRC 91C 93C and provide analog output proportional to the Kelvin temperature of the display or control sensor for the purpose of recording either with strip chart recorder or other similar device the sensor temperature The analog output is present on the J3 MONITORS connector the 91C 93C back panel with pin C being the V output and pin D being the V output 8225 3 SPECIFICATIONS Specifications for the Model 8225 Analog Output are given in Table 8225 1 8225 4 INSTALLATION The 8225 can be installed in the DRC 91C 93C Option Slot 1 or Option Slot 2 if a Model 8223 RS 232C Interface is not present The 8225 Analog Output 15 factory installed if ordered with a DRC 91C 93C or can be field instailed at a later date If field installation is required use the following procedure 1 Configure the red jumper on the 8225 printed circuit board for SAMPLE Display Sensor or CONTROL Co
9. Se B HEATER GND NOTE at 1 Ji J2 J3 AND S4 ARE SHOWN AS VIEWED FROM INSIDE THE UNIT LAKE SHORE CRYOTRONICS INC DRC 91C REAR PANEL INTERCONNECTI ONS DUG 14 48 13 _ 8754 87 91 91CRPINTER _ SHEET 1 OF 1 _ 91 1 Schematic DRC 91 Main Board 8 Rear Panel Interconnections COPYRIGHT 1986 LSCI 0 285 86 01 XDS10 XDS11 XDS12 XDS13 0514 0515 XDS35 XDS36 XDS37 Chest sis s14 2 O XU11 2 gt 0539 xpso 0535 0536 0519 T D D D XDS16 XDS17 XDS18 XDS19 XDS20 XDS21 16 XUG S17 Coss 085 a 0830 0532 0533 0534 E 3 JH 087 058 B osos ss R1 de REPLACEABLE PARTS LIST DRC 91C DISPLAY BOARD CABLE MB TO DB 01 4 102 072 TRANSISTOR SIGNAL PNP 2153906 81 517 105 146 SWITCH POT 100K CCM DET BA12030018 R2 S16 R3 105 145 POT 100K BA12010043 86 9 103 200 RES MTF 4 99 1W 103 181 RES NET 8 22 IND 4116R 001 220 1 15 105 651 SWITCH KEF 10901 U1 3 104 453 IC 8 BIT A D CONVERTER 0831 U4 104 310 IC 8 BIT MULTIPLEXER DM81LS95AN 5 104 526 KB DISPLAY INTERFACE P8279 5 06 104 277 IC 4 16 LINE DECODER 74LS154N 07 8 104 210 2 IC IN
10. V Chopra and G Dharmadurai Cryogenics 20 659 1980 9 D A Kleinman Bell Syst Tech J 35 685 1956 P R Swinehart L A Smith and J K Krause private communication values are consistent with numerous other measurements made at Lake Shore Cryotronics Inc Morrison Grounding and Shielding Techniques Instrumentation Wiley New york 1977 Vol 2 18 Application Notes
11. know that SENSOR ID switch number 4 is off and the curve is being selected from the SENSOR ID Switches 5 8 The above example indicates that a 9220 card is installed in Input A and that the input is reading Curve 2 which from Table 3 2 we know is the CRV 10 for the DT 470 Series Sen sors Consequently switches 4 8 for the A SENSOR ID are 00010 Since the DRC 91C knows which type of input card is present for each input assuming that two input cards were installed it will not for example allow the selection of the platinum curve Curve No 03 for a diode input card If Curve 03 is selected from the back panel SENSOR ID switch the DRC 91C will default to the lowest curve number with the correct temperature coef ficient in this case curve 00 For the case of a platinum input card and no Precision Option curves present the DRC 91C will select Curve Number 03 regardless of the settings for switches 5 8 unless of course a Precision Option exists for a positive coefficient tempera ture sensor and that curve has been selected by the SENSOR ID This is true for any type of input card If the SENSOR ID selects the wrong type of curve the DRC 91C will default to the lowest order COPYRIGHT 12 87 LSCI Model DRC 91C curve of the correct type The input card type and curve num ber for each input is also display ed on Power Up for a fraction of a second Table 3 4 Position versus Curve Correlati
12. LOCAL key is used to return the instrument from remote control by the IEEE 488 BUS or the RS 232C optional interface to front panel control When the LOCAL key is depressed and held down for more than one second the display shows the curve information for the input indicated 3 12 2 REMOTE Ihe REMOTE key is used to place the controller under remote control and to disable the front panel When the REMOTE key is depressed for more than one second the display shows the IEEE 488 address of the instrument 3 11 Section III Model DRC 91C Figure 3 2 DRC 91C Temperature Controller Rear Panel 12 13 5 D OOO w 19 IEEE 4 ec 3 e fr xxl ma O 9 6 Figure 3 2 Model DRC 91C Cryogenic Thermometer Rear Panel Description Tx Line cord receptacle with fuse and voltage selection 2 sensor INPUT A connector 21 Sensor INPUT connector 72 4 CONTROL input selector switch 5 SENSOR A ID 6 SENSOR B ID 75 Monitors output of Sensor INPUT A and Sensor INPUT B buffered voltages and 8225 linear analog output option J3 8 REMOTE SENSOR ID J5 Position data for option only 9 IEEE 488 address switch 10 IEEE 488 connector J4 11 HEATER OUTPUT Power terminals J6 J7 J8 12 Optional interface access plate J10 8223 RS 232C Option 13 Optional interface access plate 29 8229 Scanner Option 14 MAX HEATER POWER Limit Optional co
13. the Terminal Block Locate the test points 24 CNT V and TP1 GND 2s of the Calibration Card Avoid using clip on leads during calibration because they do not make good electrical connections Attach test equipment lead wires with the terminal screws calibration procedure is divided into three parts 1 Calibration of the Secondary Sensor Current Source of the Calibration Control Signal Amplifier and Rear Panel Offset Adjustment Calibration of the Thermocouple and Secondary Sensor A D converters the 9305 Thermocouple card 9305 9 1 Secondary Sensor Current Source Calibration l Connect the DVM plus lead to terminal 1 and the DVM minus lead to the I terminal Adjust the trimpot labelled 10 so that the DVM reads 1 000 voit 0 001 volt COPYRIGHT 6 88 LSCI 9305 Thermocouple Input Card 9305 9 2 Control Amplifier and Rear Panel Offset Adjustment Calibration 1 2 2b With the front panel of the instrument select the thermocouple input and place in the V voltage units the disable on DRC 91C Reference Junction Compensation by opening 0 switch 3 of the appropriate SENSOR ID on the rear of the instrument See Section 9305 7 2 On the DRC 93C disable Reference Junction Compensation by using the SENSOR SCAN and or keys The Display should show 9305 when the SENSOR key 15 pressed See Section 9305 7 3 Connect the DVM plus and minu
14. 4 31 amp 4 a SECTION MAINTENANCE Dl INTNODUCTLON s de 4e ge O4 de 5 1 5 2 GENERAL MAINTENANCE 5 1 5 3 FUSE REPLACEMENT o x 5 1 5 4 LINE VOLTAGE SELECTION M wk ey Oe 5 1 5 5 PERFORMANCE VERIFICATION 5 2 5 5 1 Performance Verification Connector gt 5 2 5 5 2 Performance Verification Procedure 5 2 5 6 CALIBRATION 5 5 2 5 6 1 Input Card Calibration d 5 2 5 6 2 Set Point Voltage Calibration a 5 2 12 87 TABLE OF CONTENTS Cont d 5 6 3 Calibration of GAIN RATE and RESET 5 3 5 6 4 Calibration of Power Output 5 3 5 7 TROUBLESHOOTING a a 5 4 SECTION ACCESSORIES INPUT CARDS AND OPTIONS APPENDIX Standard Curve Data APPENDIX B Sensor Curve Character Information 4 APPENDIX Error Code Summary LIST TABLES AND SECTION I GENERAL INFORMATION Table 1 1 Specifications Model DRC 91C Temperature Controller SECTION II INSTALLATION Table Figure Table Figure Table Figure Table Table Line Voltage Selection Typical I
15. 69 33 8 PID CLke 5 4 gc 1P29 SU4 16 CAIN 0 16 PID DATA 28 CRIS B Scone 1 45 lt TSC914 D 2 51 4 13 AN OUT RNG amp R79 4 75K X 18 Uie SL4 33 RESET V IN DATA CLK Teas SL4 36 RATE V CR16 14468 28 R17 ADTS33LN 2 ET ond PIN 4 PEN 1 T amp C914 8 Me mum __ LAKE SHORE CRYOTRONICS INC E MAINBOARD c PID CONTROL V V E 89 29 91 445 85 81 a SHEET GF 7 Figure 91 1g Schematic DRC 91C Main Board 6 PID Control TPi8 TPIS 21 CR19 1N4749A E 3 5834 51 258234 _ Tees 0 6 D 514 921 LOW L 4 3 PUR HI LO CND V 17 e vec vref 831 B V 1514 23 TP15 SLB 29 POT CLK 518 27 CS POT V E LAKE SHORE CRYOTRONICS INC BRC B1C MAINBOARD POWER OUTPUT STAGE 12 83 37 CONT V CONT V 5 D 0 CONT ID SP GND QF SP CONTROL A 54 CM MD P D Eo En x AS 5 4
16. MODEL DRC 941cCc TEMPERATURE CONTROLLER Input Card Configurati n Input Standard 3 volt Configuration Input B 0 9210 3 6 6 Volt Diode 9215 15 Standard 15 Nanofarad Capacitance Input E 150 150 Nanofarad Configuration 9220 3 Standard 3 volt Configuration 6 6 Volt Configuration P2 100 ohm platinum conversion module P3 1000 ohm platinum conversion module R1 27 ohm Rh Fe conversion module 9305 Thermocouple Input Card 9317C Ultra low 0 3K Germanium input Card an 9318C Germanium Carbon Glass Input Card No Input Card Precision Option s 8223 RS 232C Interface C 8002 C 8225 Analog Output Interface 0 10 volt Output Power option 8229 Scanner Input Option C wo weo High Resolution Set Point This manual applies directly to iristruments with Serial Number s 16000 and higher COPYRIGHT 1987 Lake Shore Cryotronics Inc Westerville Ohio U S A WARRANTY Lake Shore Cryotronics Inc the manufacturer warrants this product to the owner for a period of 12 months from the date of shipment During the warranty period under authorized return of instruments or component parts to Lake Shore freight prepaid the company will repair or at its option replace any part found to be defective in material or workmanship without charge to the Owner for parts service labor or associated customary shipping cost Rep
17. N11N12N13 N14N15 26 characters plus up to 2 terminators where may vary in position dependent on units and temperature N4 N5 is the Sign Display Sensor reading and units Ng N1g is the Sign Control Sensor reading and units N41 N45 is the Sign Set Point and units Examples of the Display reading N NoN3 N4N5 F N1NQN3 N4N5 R or 1 Note that all are free field where the units are K C F V and the sign may for the and scales 4 13 SAMPLE PROGRAMMING 4 13 1 HP86B Keyboard Interactive Program The following program for the HP86B is an interactive program with the keyboard of the computer For example when the user sees the prompt on the screen and types in a valid DRC 91C command such as WO the program will result in the display of the DRC 91C response on the screen 10 REM Set IEEE Address to 12 20 REM Address Switch 1 to get CR LF 30 REM This program allows the user to communicate with the 91C interactively from the computer keyboard 40 DIM 5 100 Must be increased for curve information 50 INPUT BS INPUT KEYBOARD COMMAND 60 OUTPUT 712 5 SEND COMMAND TO 91C 70 ENTER 712 5 RECEIVE ANSWER FROM 91C Qe 80 DISP 5 DISPLAY ANSWER 90 GOTO 50 100 END 4 24 COPYRIGHT 3 88 LSCI Model DRC 91C Section IV 4 13 2 National Instrum
18. monitoring as well as for control selection For the 9210 3 configuration it is multiplied by 1 for the 9210 6 configuration it is multiplied by 0 457771 3 0000 6 5535 9210 6 CALIBRATION The 9210 was calibrated to specification in the configuration specified prior to shipment If recalibration is needed refer to the following procedure The following equipment is used to calibrate the 9210 Diode Input Card 1 Digital Voltmeter Multimeter DVM 4 digit resolution or better COPYRIGHT 12 87 LSCI Model DRC 91C 93C 2 Precision Standard Resistor 100 kilohms with a tolerance of 0 01 or better 3 Precision Voltage Source capable of supplying a voltage with an accuracy and resolution of 100 microvolts out of 10 volts or better The unit should be allowed a one hour warm up time to achieve rated specifications Use the following procedure to calibrate the 9210 Diode Input Card 1 Remove the three panel screws and slide the panel cover off 2 Set 104A Current Connect the precision resistor across the A and B I pins of the five pin input connector for the input the 9210 occupies Connect the DVM plus lead to the I pin and the minus lead to the I pin Adjust the trimpot marked LOLA on the calibration cover for the appropriate Input Card until the voltage across the resistor is 1 0000 0 0001 volts 3 Calibrate the Buffered Sensor Output Signal Connect the DVM plus lea
19. 12 13 14 15 22 characters plus up to 2 terminators where C1 is the SCAN status H olding or S canning 2 3 12 13 is the AO 4 and BO dwell times in seconds 14 15 is the SCAN position AO A1 A2 A3 A4 card is present since one current source is associated with the 4 inputs The display which will scan is the sample display 4 10 5 Holding the Scan Function Command The Scan can be stopped any time over the IEEE 488 Bus by sending out the YH command The scanner should be in hold when any of the other scanner commands are sent to the scanner 4 10 6 The WY Data String This command gives the scan informa tion including whether the instru ment is scanning or holding the channel dwell information and the scan position COPYRIGHT 3 88 LSCI 4 11 The Service Request Status Register Status Reports and the Status Register Mask As mentioned earlier a Service Request can be initiated by the DRC 91C to indicate a function has been performed or a limit overload or error has been encountered The DRC 91C does this by pulling its SRQ Service Request management line low The BUS CONTROLLER uses the serial poll SPOLL to obtain the contents of the register in the DRC 91C called the Status Register The DRC 91C Status Register is a single byte of data from the DRC 91C containing five bits called the Status Reports These Status Reports indicate when certain pro
20. 2 103 077 105 403 104 081 104 005 4104 001 104 665 104 074 104 020 _ 102 010 102 041 104 345 104 511 104 660 104 528 _ 102 040 103 990 MOSFET REGULATOR REGULATOR 45 VOLTAGE REFERENCE 2 5v C24 user PART NUNBER 099 M a Description BE POLY 0015 400v CAP TANT 35 cap 4 4100000 TANT SMF 10V DIODE SWITCHING ae CONNECTOR 6 Post RA HDR Bf CTRIMPOT Tus arene _ A D CONVERTER CHANNEL OPTOCOUPLER Te MICROPROCESSOR EPROM PROGRAM 8 LATCH VOLTAGE REFERENCE 1 aa CRYSTAL 5 0004 05 C25 xus 1 1 J JMP1 EET UT dem M claim qe 22 71 1 i llo t IL t MODEL 9305 INPUT CARD MFR PART NO P 1190106x0035081 NE MPP 11 47MFD 11509155 901042 _ 2420 09 75 1061 1508 38163 7905 2778050 LM336B2 2 5 OWCPL 2731 0 31 27 64 3 P82c82 5 000N az Br TM PUER Figure 9305 1 Model 9305 Thermocouple Input Car
21. 5 15 60 uw tes tea 9 PWR V ADJ Pi 13 gt v 4 gt gt 8 8888 88 545 LAKE SHORE CRYOTRONICS INC SiC CALIBRATION AND SERVICE CARD Figure 910 3 DRC 91C Calibration and Service Card disci part Number 104 310 104 210 104 207 103 990 REPLACEABLE PARTS LIST ifs SX MI 10 10 MICA 1 5004 x CAP 047MF POLY 600V _ CAP TANT 33MF 25V MICROPROCESSOR D eo __ 10 416 LINE DECODER 2 8 BIT LATCH FC EPROM PROGRAM 8 8 WOVRAM UPS sias BIT MULTIPLEXER Lb tc 0 C HEX 5 p HEX INVERTER 5X 5 000 LLLA een Cul LL ERU e 1 i Eo IH Ax A9 MICROPROCESSOR CARD MER PART NO 1190106 0035081 p 915 01000030 WwMF6S47 S 1990336 0025 2 _ renege acd 28200 esta25v P DMBILSSS H upi 5 5 100 uU EM uu HE Tea Te e a SCRE OR x RST A iis NT QM lt lt lt g sonF Ius BIF G PAK 5 an 21 29 gt
22. The XCN N5 command is the most powerful curve command in the 91C It allows for the remote input of Sensor Curves The Sensor Curves that can be input using the XC command are 06 thru 31 note that the first five curves 00 thru 04 are the Standard Curves with Curve 05 reserved The format for the XC command is given in Table 4 16 The format for the XC command must be followed for the curve entry to be successful Following the 1 2 where N4N5 is between 06 and 31 is a comma Then up to 18 characters be entered as a curve information line At least one character is required and any more than 18 characters are ignored If 18 characters are input the last 6 are used in the Sensor Curve Information Table as capsule description of the curve in the 8000 Series Precision Option curves these 6 characters are used to indicate the sensor serial number The 18 characters must be immediately followed by a comma The data points are then input in the form X XXXXX comma TTT T The X XXXXX input is in Voltage Capacitance or LogR Refer to Table 4 19 for the conversion of the raw units information into the format required for the XC command The unit automatically COPYRIGHT 3 88 LSCI Model DRC 91C fills leading and trailing zeroes in the data point A data point entered as 0 8 70 would be converted by the unit into 0 80000 070 0 The data points must be entered in units order After all the
23. thermocouples supported with internal curves that enable the controllers to temperature units C F and K as well as voltage in millivolts The 9305 utilizes secondary temperature sensor to monitor the Reference Junction room temperature and provide curve compensation The Reference Junction Compensation disabled so the 9305 can be used with external compensation techniques Offset Adjustment is provided adjacent to the Terminal Block to compensate for thermocouple variations and System irregularities COPYRIGHT 6 88 LSCI operate in 9305 2 2 Specifications Specifications for the Model 9305 Thermocouple Input Card are given in Table 9305 1 The temperature range for each type of thermocouple is given in Table 9305 2 9305 3 INSTALLATION The 9305 can be installed in a DRC 91C or a DRC 93C as either Input A or Input B The 9305 is installed prior to shipment if ordered with a controller If only one card is ordered and its input 16 not specified when ordered it is installed in Input A When a card is ordered for field installation the Input Card Configuration Table located on the first page of the Instruction Manual should be updated to keep documentation current Use the following procedure for the installation of the 9305 Thermocouple Input Card WARNING To prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment be
24. 1186 CS 401lILG Ci 11 1972 12 9423 15 3912 14 9303 9 3561 5 9762 4 3180 3 9989 1248 CS 5012 6 5884 7 1334 9 0452 10 1940 14 0355 21 7233 91 0746 130 140 10002 Notes 1 9215 15 configuration 2 9215 150 configuration 3 No Calibration Data Available 9215 2 COPYRIGHT 2 88 LSCI Model DRC 91C 93C 9215 3 NOTES ON 5 501 CAPACITANCE SENSORS 9215 3 1 Short Term Stability The capacitance sensor provides very stable temperature control over long periods of time However since an operational aging phenomenon exists some care must be exercised in their use The short term minutes to hours capacitance temperature drift is initiated by a thermal perturbation of the sensor In order to minimize this short term drift it is recommended that approximately one hour be allowed for the sensor to stabilize after the initial cooldown The short term drift is then on the order of a few tenths of millikelvin minute at 4 2K several millikelvin minute at 77K and one millikelvin minute at 305K For temperatures less than 290K the short term drift is such that the equivalent tempera ture will decrease with time and for temperatures above 290K saca increase with time 9215 3 2 Thermal Cycling and Reproducibility Thermal cycling of capacitance sensors can produce variations in capacitance temperature values equivalent to several tenths of a degree over the short term days The
25. 4 Connect the wiring harness mating connector 9317C 9318C Input Card making sure that the wiring harness locking tab is seated over the extended edge the wiring harness mating connector Plug the 9317C 9318C into the Input Card Slot with the component side facing to the left of the unit as viewed from the front Make sure the card is thoroughly seated Verify that the wiring harness is in place correctly by noting that the A or B on the harness connector is facing up if it is not review the harness installation again 5 Install the calibration cover by reversing step 2 6 Install the top panel 9317C 9318C 5 OPERATION The 9317C 9318C is a highly complex microprocessor controlled Input Card It s resistance measuring technique is distinctly different from the way a DMM would measure resistance Most DMMs force a large enough signal across the device being measured to make any thermal offset negligible Using this method in a cryogenic environment could add a significant amount of power in the form of sensor self heating to the test system The 9317 9318 Input Card limits the amount of power added to the system by limiting the voltage across the sensor to 1 9317C or 10 millivolts 9318 9317 9318 also reverse the current polarity order to correct for thermal EMFs in the sensor connections and leads The 9317C 9318C current source has four ranges 0 1 to 1 m
26. 49 LSCI REPLACEABLE PARTS LIST 9215 IMPUT CARD arn oen eure MFR PART NO Number 101 034 101 025 106 142 102 072 105 649 104 051 102 075 104 461 104 099 104 460 104 001 104 010 102 020 104 087 104 078 104 355 102 037 104 054 104 101 104 356 Part 1 0 100 CAP PP 33MF 100V CONNECTOR IC TO BP 6 POST LOCKING HEADER TRANSISTOR PNP SIGNAL SWITCH 2 POS 4 POLE INTERLOCKING IC TIMER MOSFET N CHANNEL 1C A D CONVERTER IC P S SHIFT REGISTER A D REFERENCE IC IC F V CONVERTER REGULATOR 5 IC DUAL OP IC SWITCHED CAPACITOR IC OPTOCOUPLER VOLTAGE REFERENCE 10V 1 OSCILLATOR IC DECADE COUNTER OPTOCOUPLER MPP2X 1 0 100 10 MPP 11 33MFD 2420 09 75 1061 2N5906 2XMTA7 5 NONE 4UGRP CM7555IPA VN0535N2 1CL7104 16CPL CD4021BCN ICL8068ACPD LM331N 79105 5 1 LT1043CN 74016000 REF 01EN8 SG 10 10KA 4029CBN 78016010 NUM MEN IE ol muselo ol misse edo o NEM ju 2000 OPEN CAL ve A D CAL V A D CAL P2 4 gt V CONT 2 5 3 89K 0 orla ON 2 4 C 1 36 D C 1 32 GND D B 5 45 15 9 CP1 31 DATA IN lt Pi 89
27. BVD A D C P1 33 CLK C 1 18 DATA OUT 8215 CAPACITANCE INPUT CARD SCHEMATIC b 585 97 81 lt lt Figure 9215 1 Model 9215 Capacitance Input Card Model DRC 91C 93C 9220 Input Card 9220 USER CONFIGURABLE INPUT CARD OPTION 9220 1 INTRODUCTION This section contains information pertaining to the Model 9220 Diode and Platinum User Configurable Input Card Included is a description specifications installation operation and maintenance information 9220 2 DESCRIPTION The Model 9220 Diode and Platinum Input is designed to be installed in a DRC 91C or DRC 93C to convert either the Input A or Input B or both with two options to accommodate either diode or positive temperature coefficient sensors such platinum or rhodium iron The 9220 3 configuration is equivalent to the 9210 3 configuration described earlier The 9220 6 configuration is equivalent to the 9210 6 configuration The 9220 P2 converts either Input A or B or both with two options to accommodate 100 ohm platinum RTD s which conform to DIN 43760 tolerances 0 1 have interchangeability of 0 1 at OC and a temperature coefficient of 0 00385 9C from O to 100 C This card also be configured as a 9220 P3 1000 ohm platinum ofr 9220 1 rhodium iron input card 9220 3 SPECIFICATIONS Specifications for the Model 9220 User Configurable Input Card ar
28. GAIN INQ4N5 etc DN4N5 etc integral RESET Derivative RATE Heater Range Table Scanner Setup and Selection Commands Select Channel AC4 Set the Scanner channel dwell time AO thru 4 Enable the S CAN function Disable or H old the SCAN Table Status Register Mask Command 4 13 1 2 Set the Status Register mask COPYRIGHT 3 88 LSCI Section IV 4 6 1 Commands and Requests The device dependent commands to program the DRC 91C are given in Table 4 4 The 91 must be addressed a LISTENER to receive instruction or string of instruct ions from the Command list The DRC 91C input data format does not require a set number or set sequence of Commands to implement proper instrument set up These Commands are processed only after the terminators TERM1 TERM2 are sent across the bus The listing and explanation of the 91C commands are summarized in Table 4 4 There are commands for Interface Setup Instrument Setup Control Setup Scanner Setup and Status Register The Output Statement Requests are sent by the BUS CONTROLLER to the DRC 91C to tell the 91C what data to output when data output is requested These requests are listed in Table 4 5 and the data formats are described in detail in the following tables as well as the adjoining text associated with those tables Table 4 5 Model DRC 91C 4 7 INSTRUMENT SETUP COMMANDS AND REQUESTS 4 7 1 EOI Status The
29. Note on the calibration cover the position of Option Slot 2 which the 8229 will occupy 2 Remove the four screws that secure the calibration cover to its clips and remove the cover Remove the two back panel mounting clips that secure the J9 blank cover plate to the interface opening and remove the plate 3 Plug the internal sensor lead cable into the 8229 printed circuit board PCB with the locking tab configured properly Plug the 8229 PCB into Option Slot 2 with the component side to the left of the unit as viewed from the front Thread the 8229 internal cable along the inside edge of the rear panel so that it won t interfere with the installation of the calibration cover or top cover 4 Position the 24 pin 8229 Scanner connector in the J9 opening on the back panel and secure it in place using the screws provided 5 Disconnect the Input Card wiring harness from the A Input Card by lifting the locking tab on the Input Card connector and pulling on the body of the wiring COPYRIGHT 12 87 LSCI Model DRC 91C 93C harness mating connector Plug the Input Card wiring harness into the 8229 input making sure that the wiring harness locking tab is seated properly Thread the 8229 output cable along the component side of the 8229 and plug the cable into the Input Card making sure the locking tab is seated properly 6 Install the calibration cover by reversing procedure 2 7 Install the top cover panel 8229
30. Sensors Ordered Separately Card optimized for CGR Series Carbon Glass or GR Series Germanium Resistance Thermometers Other negative temperature coefficient resistors such as thermistors can also be used Sensor Response Curve The DRC 91C 93C display resistance in ohms directly calibrated sensor and an 8001 Precision Option curve generated using Lake Shore s proprietary Polynomial Interpolation Algorithm are required for the unit to display temperature accurately Input Resistance Greater than 109 ohms sensor voltage measurement Maximum Sensor Power Dissipation Depends on sensor resistance Voltage applied is 1 millivolt for the 9317C power is 1 R in micro watts or 10 millivolts for the 9318C power is 100 R in microwatts Display Resolution 5 digits Displays 0 000 to 9999 9 ohms for the 9317C and 0 000 to 99999 ohms for the 9318C Resultant temperature accuracy is a function of sensor characteristic and is the product of the input accuracy in percent times R dT dR plus any transfer inaccuracy introduced by the sensor response curve Temperature Control Signal Card generates an analog voltage output Signal which is related to the sensor temperature The instrument generates a similarly related set point voltage based on the set point resistance or temperature selected Real time analog comparison of these two voltages provides the required control signal 9317 9318 2 COPYRIGHT 12 87 LSCI Model DRC 91C 93C
31. Since the card has to provide a signal across the sensor that will control the heater power as well as measure resistance or temperature it can no longer force the sensor signal to 1 05 or 10 5 millivolts immediately When a set point is entered by the user the DRC 91C 93C calculates its equivalent control sensor resistance From this resistance and the calibration constants current and voltage for the 9317C 9318C input card the set COPYRIGHT 12 87 LSCI Model DRC 91C 93C point voltage which will result in a sensor voltage as close to 1 05 or 10 5 millivolts as possible when the control point is reached is calculated If the thermal correction is active and there has been a valid thermal value deter mined it is included the calculation If no valid thermal has been determined or the thermal correction is inactive a thermal value of 0 is used The resultant voltage is then sent to the main board of the controller as the set point voltage or equivalent resistance for control The 9317 9318 input card then determines if the control sensor resistance is above or below the equivalent set point resistance If the actual resistance is less than the set point resistance an over temperature condition exists and the heater power should be off The 9317C 9318C changes the current it applies to the sensor in order to maintain between 0 8 and 1 0 9317C or 8 and 10 millivolts across it until the set p
32. With some instru ments GTL also unlocks front panel controls if they were previously locked out with the command SPE Serial Poll Enable SPD Serial Poll Disable Serial polling is used to obtain the SRQ Status Register The Status Register contains important operational information from the unit requesting service The SPD command ends the polling sequence Section IV 4 5 4 The Unaddress Commands The Unaddress Commands in Table 4 3 are used by the BUS CONTROLLER to remove any TALKERS or LISTENERS from the bus The ATN line is asserted low when these commands are asserted UNL Unlisten LISTENERS placed in the listener idle state by the UNL command UNT Untalk Previous TALKERS will be placed in the TALKER idle state by the UNT command Table 4 3 summarizes the IEEE 488 Bus Commands acknowledged by the DRC 91C 4 5 5 Device Dependent Commands The DRC 91C supports a variety of device dependent commands to allow the user to program the instrument remotely from a digital computer and to transfer measurements to the computer These commands are sent from the computer BUS CONTROLLER to the DRC 91C as one or more ASCII characters tnat tell the device to Table 4 3 Model DRC 91C perform a specific function For example the command sequence FOK sent by the BUS CONTROLLER to the DRC 91C is used to select kelvin as the set point units The IEEE 488 bus actually treats these commands
33. as data in that ATN is high when these device dependent commands are transmitted 4 5 6 TALKER and LISTENER Status For the DRC 91C to be a LISTENER it has to be in REMOTE and can be returned LOCAL with the device dependent command or GTL addressed command as desired For most but not all computers the DRC 91C as a TALKER does not have to be placed in REMOTE operation but can remain under LOCAL control This allows the user to collect data while maintaining front panel control The HP computers will allow this mode of operation If your computer automatically places the DRC 91C in remote and keeps it in remote after the transmission is over sending the additional command MO after the request for data will return the DRC 91C to LOCAL IEEE 488 Bus Commands Message 25 86 p BE usa NN p woe Uniline cowmands 7 Remote REN Interface Clear IFC Universal Commands Local Lock Out LLO Device Clear DCL Addressed Command Selected Device Clear SDC Go to Local GTL Serial Poll Enable SPE Unaddress Commands Unlisten UNL Untalk UNT 1107 clr7 1 712 1712 712 5 U IFC LOCAL LOCKOUT 7 CLEAR7 20 LLO U DCL CLEAR712 LOCAL712 S SPOLL 712 U SDC U GTL 20 SPE U is the controller computer Talk Address Address 21 4 6 COPYRIGHT 3 88 LSCI Model DRC 91cC 4 6 PROGRAMM
34. c AP Us DISPLAY AND DISPLAY SENSOR Units 3 8 5 1 Units Select 19 C CO CJ LJ C9 CJ C CJ LJ C9 CJ CO C9 CJ QOO odo OY UI Ul UL e 3 8 5 2 Sensor Units Mode 3 8 5 3 Voltage Units gt 3 8 5 4 Resistance Units 3 8 5 5 Capacitance Units s gt 3 8 6 Display Resolution s s s s 3 8 6 1 Temperature Display Resolution Set 3 8 7 Filtering the er 3 3 9 SENSOR CURVES 3 9 1 Standard Curves 3 9 2 The Precision Option Table 3 10 SENSOR CURVE SELECTION 3 10 1 SENSOR ID Switch 4 Open 0 3 10 1 1 Display of Accessed Curve 3 10 2 SENSOR ID Switch 4 Closed 1 No REMOTE SENSOR ID Present 3 9 3 10 3 SENSOR ID Switch 4 Closed 1 REMOTE SENSOR ID Present 3 9 3 10 4 Addition of 8229 Scanner Option 3 10 3 10 5 Display of Accessed Position and Assigned Curve 350 3 10 6 Sensor Curve to Sensor Position 3 10 3 11 CONTROL BLOCK o ca XE de edes d Ue uo 2 3 11 1 POINT AO X 3 11 2 GAIN un TO 3 11 3 RATE ss 8 gt gt o e 3 10 3 11 4 RESET UR
35. closed or power open DRC 91C is shipped to read in power 2 4 REMOTE SENSOR ID Connector The REMOTE SENSOR ID connector J5 on the rear panel receives POSITION DATA from a Model 8084 or 8085 Sensor Scanner or a Model SW 10A Ten Sensor Selector Switch The REMOTE SENSOR ID Interconnecting Cable and REMOTE SENSOR ID connec tor assignments are given in Table 2 5 COPYRIGHT 12 87 LSCI Section II Table 2 5 REMOTE SENSOR ID Connector Assignments REMOTE SENSOR ID Connector Pin Function Bit 0 BO LSB Bit 1 B1 Bit 2 B2 Bit 3 B3 Bit 4 4 Digital Ground The POSITION DATA is the binary representation of the remote posi tion Table 3 4 gives the POSITION DATA binary combinations The remote position input can be used to select specific sensor curve tables stored in the DRC 91C The correlation between remote position and sensor curve is given in Sec tion III The REMOTE SENSOR ID can be expanded to allow for the use of up to three 8084 or 8085 Sensor Scanners with the 8082 Position Data Adapter Remote position 1F 31 is reserved to indicate that more than one scanner is active to the 8082 When this condition is present the DRC 91C displays ERRO9 until the fault is corrected 2 5 488 INTERFACE Connector The IEEE 488 Connector on the back of the DRC 91C is in full compli ance with the IEEE Standard 488 19 78 The connector has metric threaded mounting studs visu
36. platinum This default will only occur if a curve of opposite temp erature dependence has been inad vertently selected by the user In the case of the 9215 card tempera ture units are not allowed due to COPYRIGHT 12 87 LSCI Section III the inability of this sensor to hold a calibration upon cycling 3 8 5 2 Sensor Units Mode 3 8 5 3 Voltage Units voltage mode is allowed for the 9210 3 and 6 configurations the 9220 3 and 6 configurations as well as the older version 8210 and 8211 cards In the voltage mode the display has a resolution of 0 1 millivolt with the full scale range dependent on the input card 2 9999 volts for the 3 configurations and the 8210 card and 6 5535 volts for the 6 configurations and the 8211 input card actual Input Card resolution is 0 05 millivolts and 0 1 millivolts respectively Ifa voltage exceeding full scale is ap plied to the displayed input an overload condition is present and is indicated by OL on the display 3 8 5 4 Resistance Units Ihe Resistance mode is allowed for the 9317C 9318C and the 9220 2 P3 and R1 configurations as well as the older 8219 P2 the 8219 3 and 8219 R1 cards Ihe display range and resolution for the 9317C is 0 000 to 9999 9 ohms the 9318C is 0 000 to 99999 ohms Note that the resistance automatically ranges from to to to as the resistance increases in value If the input resistance exceeds the re
37. the last one received will be acknowledged Programming Codes and Output Statements can be sent in the same command string For example the command string 524 5 40120 25 2 would result the Set Point being updated to 24 5 the Gain to 40 the Reset to 20 the Rate to 25 and the Heater Range to 1073 No Output Statement was given so no response will be output by the interface The command string 524 5P40T20D25R2WO will result in the WO contents being output the interface Refer to Section 4 for a detailed discussion of the Output Statement commands COPYRIGHT 12 87 LSCI Model DRC 91C 93C Tables 4 11 and 4 12 give the Program Curve Summary The XDT XDA and XDNQ4N5 commands are Output Statement style commands which result in a response from the interface The balance of the commands are Programing Code style commands which do not result in a response from the interface Care must be taken with the XCNjN5 command not to overrun the 256 character buffer of the 8223 interface in the IEEE operation if a hardware problem is detected in modifying one of the memory locations ERRO1 error wlll be displayed in the Display and instrument operation will be halted Consult factory representative if this error occurs There are three errors that could be detected by the 8223 interface as defined in Table 8223 6 Detection of an error does not effect the operation of the interface The so
38. typically better than 20mK within this region is 0 03K Above 28K system accuracy gradually moderates to a typical value of 75mK above 40K See the Lake Shore Cryotronics Inc Low Temperature Calibration Service brochure for additional discussion of calibration accuracy The Model DRC 91C can also be used with the 29220 input card which handles both diodes and positive temperature coefficient metallic resistors i e platinum or rhodium iron resistors The DIN curve is standard within the instrument and is called up automatically unless positive temperature coefficient precision option is selected by the SENSOR ID for that input The accuracy of the reading is dictated by the sensor and its conformity to the DEN curve tolerance on these devices is given on the technical data sheet for the Lake Shore PLATINUM RTDs The combined accuracy of the instrument and a calibrated resistor with a preci sion option is on the order of 40mK over the useful range of the sensor above 40K for the platinum Note that a precision option is required 1 2 Model DRC 91C for a rhodium iron to read correct ly in temperature The Model DRC 91C with the 9318C germanium carbon glass input card results in the most accurate system below 50K in temperature For both Sensors precision option is required to read in temperature Near 4K the overall accuracy of the system including the calibra tion accuracy
39. 104 461 104 460 102 020 104 051 104 078 CAP PP 1 0MF 100V CAP PP 33MF 100V CONNECTOR IC TO BP 6 POST LOCKING HEADER TRANSISTOR PNP SIGNAL SWITCH 2 POS 4 POLE INTERLOCKING MOSFET P CHANNEL IC OP AMP VOLTAGE REFERENCE 6 95V IC OP AMP IC OPTOCOUPLER IC OPTOCOUPLER IC P S SHIFT REGISTER IC A D CONVERTER IC A D REFERENCE REGULATOR 5V IC TIMER IC SWITCHED CAPACITOR REPLACEABLE PARTS LIST ANALOG INPUT CARD MPP2X 1 0 100 10 1 0 100 10 MPP 11 335MFD 2420 09 75 1061 2N3906 2XMTA7 5 NONE 4UGRP 3N163 LM308 LM399H 76016000 74016010 CD4021BCN ICL7104 16CPL ICL8068ACPD 79105 1 555 1 LTC1043 wes PIED esv P173 2 lt 2 2 2 io e 3 pe a be Lae LTC1242 ua 9305 THERMOCOUPLE INPUT CARD 9305 1 INTRODUCTION This section contains information pertaining to the Model 9305 Thermocouple Input Card Included is a description and information on Specifications installation operation and field calibration 9305 2 CATIONS DESCRIPTION AND SPECIFI 9305 2 1 Description The Model 9305 Thermocoupie Input Card is designed to be installed in a Lake Shore DRC 91C or DRC 93C Temperature Controller allows either Input or Input B or both with two cards to accommodate thermocouple sensors Chromel vs Gold 0 03 at Chromel vs Gold 0 07 at Fe E and
40. 488 TEST PROGRAM Quick Basic 3 0 Example THIS PROGRAM WAS WRITTEN FOR THE NATIONAL INSTRUMENTS GPIP PC2 IEEE 488 CARD FOR IBM PC AND COMPATIBLES This program will allow the user to communicate with Lake Shore s instruments interactively from the keyboard of an IBM compatible computer which has a National Instruments GPIB PC2 installed common shared IBSTA IBERR IBCNT TEMPS dev12 call IBFIND TEMPS TEMP Required command to address instrument AS space 10000 Loop1 input B Entered from keyboard while running BS BS chr 13 chr 10 Add CR and LF to command call IBWRT TEMP BS Send command to instrument call IBRD TEMP AS ENTER from instrument SEE BELOW FOR I 1 to 10000 C MIDS AS 1 IF C CHR 13 THEN Loop2 PRINT C NEXT I Loop2 PRINT AS space 10000 Clear AS GOTO 1 END COPYRIGHT 3 88 LSCI 4 25 Section IV Model DRC 91C Lake Shore Cryotronics instruments will return the data requested but if the command input to the instrument does not request any information the instrument will respond with the information last requested 4 13 4 HP86B Bus Commands Program The following program is for the HP86B and exercises the various bus commands 10 REM Set IEEE Address to 12 20 REM Address Switch 1 OPEN 0 to get CR LF 30 DIM A 42 For longest string 40 OUTPUT 712 wo Note WO 50 ENTER 712 5 Ask for string WO 60 DISP WO 5 Display string WO 70 DISP
41. 5 1742 5 0315 4 9126 4 5494 4 3810 4 1733 3 9952 3 8132 3 6270 3 4370 3 2435 2 9477 2 6452 2 3372 2 0242 1 6004 1 1693 0 6232 0 0705 0 5986 0 7158 0 8431 0 9944 1 1940 1 4841 15 0010 COPYRIGHT 6 88 LSCI Model DRC 91C 93C Table 9305 4 cont Breakpoint Number Jo0YU pmP Chromel vs Constantan E Temp Vere mV 15 0000 9 8355 9 8298 9 8182 9 7956 9 7570 9 7013 9 6204 9 5071 9 3366 9 1345 8 9030 8 6475 8 3673 7 9064 7 3943 6 8386 6 2400 5 3831 4 4564 3 4702 2 1605 0 7666 0 9948 2 8428 4 7704 7 1149 9 5570 9305 Thermocouple Input Card 15 0000 6 4582 6 4551 6 4486 6 4376 6 4205 6 3951 6 3529 6 2913 6 2149 6 1022 6 0099 5 8634 5 6989 5 5156 5 3166 4 9881 4 6240 4 2267 3 7994 3 1866 2 5259 1 6463 0 5186 0 8688 3 1298 4 9999 7 6164 9305 Thermocouple Curves Copper vs Constantan Temp K mV 15 0000 6 2584 6 2523 6 2401 6 2184 6 1888 6 1404 6 0615 5 9535 5 7995 5 5753 5 3204 5 0337 4 7194 4 3767 3 8781 3 3278 2 7342 1 9295 1 0586 0 1254 1 0616 2 3247 3 6639 5 3095 7 0419 9 1113 11 2758 1 13 8053 14 9685 15 0010 9 6125 12 2790 15 0010 12 4425 13 5573 15 0010 COPYRIGHT 6 88 LSCI 9305 13 LSC REPLACEMENT PARTS List Part Number _ 101 034 101 001 101 137 101 027 2 101 132 102 064 106 142
42. 8 1 9 2 3 4 5 D 6 E 7 F 4 12 COPYRIGHT 3 88 LSCI Model DRC 91C Section IV DRC 91C Output Request Summary for Instrument Setup eee ce eee ee ee ee hee e e ee ee ee ehe ee ee ee ee dee ee ee ee e de dee dee dee dece eee ee ee e kk Functional Description and B Input Information Table 4 8 the A N4N5 is the A N4 is the A C10 is the A TET 475 Ng is the B is the B 4 8 7 The W1 Data String This Data String gives the Display Sensor Control Sensor Set Point Units Remote Position the A ID curve number A display resolution and units the B ID B curve number and the B display resolution and units The data string will have the following format A0 B0 K 00 A20 02 3 K B42 04 2 K The above string indicates that the Display Sensor is A0 the Control Sensor is B0 set point is in kelvin units the remote position is off the SENSOR A ID indicates that the Digital Filtering for this channel is ON and the curve assigned is 4 the curve being used is also 4 B resolution is 10mK B units are also in kelvin Both channels are using the DT 470 Curve 10 the difference is that INPUT A is set for an upper limit of 325K and INPUT B is set with an upper limit of 475 COPYRIGHT 3 88 LSCI ID 00 through FF curve number 00 through 31 Input Resolution 0 xxx to 4 Display Units
43. 8271 21 Sensor Heater Cable is a six pair individually shielded cable with two five pin miniature hexagonal plugs which mate with the SENSOR A and SENSOR B connectors on the back panel of the DRC 91C Temperature Controller addition to the sensor connectors it has a dual banana plug for heater output and a single banana plug for heater output shield and are cable s mechanical electrical specifications included with the cable 6 2 2 4 8271 22 Sensor Heater Output Cable The 8271 22 sensor Heater Output Cable consists of two discrete cables The first is a six pair individually shielded cable with two five pin miniature hexagonal plugs which mate with the SENSOR A and SENSOR B connectors on the back panel of the 91 Temperature Controller In addition to the sensor connectors it has a dual banana plug for heater output and a single banana plug for heater output shield The second cable is three pair overall shielded cable for the Monitors Outputs The cable s mechanical electrical specifications are included with the cable COPYRIGHT 12 87 LSCI Model DRC 91C 6 2 3 Cartridge Heaters 6 2 3 1 50 Ohm Cartridge Heater This cartridge heater is 1 4 in diameter 1 in length and is rated at 50 watts 6 2 3 2 25 Ohm Cartridge Heater This cartridge heater is 3 8 in diameter by 1 in length and is rated at 25 watts 6 3 Installation of Input Cards from a DRC 81C or DRC 82C Inpu
44. 9220 4 INSTALLATION The 9220 can be installed in the 91C 93C as either Input or Input B or both with two options The 9220 is factory installed if ordered with 91 or 93C Temperature Controller or can be field installed at a later date If field installation is required use the following procedure WARNING To prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment before removing cover 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off Note on the calibration cover the position of the Input Card the 9220 will occupy 2 Remove the four screws that secure the calibration cover to its clips and remove the cover 3 If an Input Card must removed disconnect the wiring harness mating connector by lifting the locking tab on the Input Card connector and gently pulling on the body of the wiring harness mating connector 4 Plug the new 9220 Input Card into the A Input Card Slot 4 or the B Input Card Slot 5 with the component side to the left of the unit as viewed from the front Connect the wiring harness mating connector to the 9220 making sure that the wiring harness locking tab is seated over the extended edge of the wiring harness mating connector Verify that the wiring harness is in place correctly by noting that the A or B on the 9220 2 Model DRC
45. Capacitance Input Card 1 Digital Voltmeter Multimeter DVM 4 digit resolution or better 2 Precision Standard Capacitors 10 nanofarad and 100 nanofarad with tolerance of 0 1 better 3 Precision Voltage Source capable of supplying a voltage with an accuracy and resolution of 100 microvelts out of 10 volts or better 9215 6 DRC 91C 93C The unit should be allowed a one hour warm up time to achieve rated specifications TO begin remove the three top panel screws and slide the panel off The procedure is divided into three parts as follows 1 Calibration verter of the A D Con 2 Zero calibration 3 Span Calibration The zero and span calibration is done with the instrument and system wiring configured as it will be used This will provide optimum accuracy because lead and stray capacitance will be taken into account 9215 8 1 A D Calibration 1 Locate DIP switch package 51 Switch 2 Under normal opera tion this switch is CLOSED 1 Change this switch to the OPEN O position 2 Connect the DVM plus lead to the Buffered Sensor Output Signal pin for the appropriate Input Card and the minus lead to the V pin on the MONITORS connec tor connect the precision voltage source across the E V and D V pins of the five pin input connector for the input corresponding to the Capacitance Card 3 Set the standard to 1 5000 volts 4 Verify that the Display indi cates
46. Characteristics Inputs Two Sensor Inputs 8229 Scanner Conversion Option provides for four additional channels of Sensor Input Display sensor can be selected from front panel or interface or display can be set to scan between sensor inputs Dwell time per channel can be set independently from O skip to 99 seconds Input character istics are a function of Sensor Input Option Installed The DRC 91C can accommodate two input options which allows the A input and the B input to each be assigned their own input card This allows concurrent use of different sensors dependent on the application The Sensors Ordered Separately DRC 91C will handle all types of diodes germanium carbon glass carbon etc negative temperature coefficient resistors thermistors platinum rhodium iron etc metallic resistors and ther mocouples as well as capacitance thermometers with proper choice of input option cards See the Lake Shore Cryotronics Inc Sensor catalog for details on the above Sensors Display Readout Display 5 digit LED Display of Sensor reading Sensor Units Volts Ohms or Nanofarads or 1 4 Model DRC 91C The Model 8229 Scanner Option provides four additional channels of sensor input to the A input The A input is channel AO with the additional inputs designated 1 4 with the selection indicated on the display Specifications Model DRC 91C Temperature Controller temperature in K C or
47. Connect the DVM plus and minus leads to the V and V Sensor Output Signal terminals of the MONITORS connector for the input being calibrated Apply a 41 9317C or 10 9318C millivolt signal to the V and V Sensor Input terminals Enable CAL 6 on the card CAL 8 is still enabled The DVM should read about 1 volt and the display of the unit should read approximately 10000 Adjust the trimpot labeled A D so that the voltage read on the DVM matches the display of the unit if the DVM reads 1 0085 the display read 10085 4b If the trimpot is adjusted wait a minimum of 10 readings before disabling CAL 6 Apply a 1 9317C or 10 9318C millivolt signal to the input and enable CAL 5 Do not adjust any of the trimpots Disable CAL 5 after approxi mately 30 seconds When the display goes to 0 the unit has completed determining the voltage input calibration constants and has stored them in the 9317C 9318C calibration EEPROM COPYRIGHT 12 87 LSCI Model DRC 91C 93C 5 Current Range 1 Value 6 Configure the 10K 93170 or 100 9318 resistor to simulate the sensor Enable CAL 4 and monitor the unit s display The display should indicate the number 106 for approximately 30 seconds then display 0 indicating the end the calibration Disable CAL 4 and continue Current Range 1 Value 60 and Current Range 2 Value 6 Substitute a 1K 9317C or 10K 9318C resistor the pr
48. D DRC 91C Program Code Summary Instrument Setup DRC 91C Summary of Output Requests DRC 91C Interface Setup Commands and Request Status DRC 91C Command Summary for Instrument Setup DRC 91C Output Request Summary for Instrument Setup DRC 91C Command Request Summary for Setpoint Setup DRC 91C Command Request Summary for the Control Parameters E DRC 91C Command Request Summary for Scanner 3 DRC 91C Command Request Summary for Status Register Mask ERO DRC 91C SRQ MASK and Status Byte Format wo E d Commands to Fix the Status Register Mask DRC 91C Output Data Statements e o s Sensor Curve Commands and Description Sensor Curve Information Table Output Format Sensor Curve output Format e gt Conversion of Raw Units Data for the XC Command 40 ILLUSTRATIONS OG EX EJUS 0 0 4 21 4 22 4 22 4 24 4 28 4 29 4 29 4 32 Model DRC 91C Section I SECTION I GENERAL 1 1 INTRODUCTION The information contained in this operations manual pertains to the installation operation remote programming options and acces sories for the Lake Shore Cryotro nics Inc Model DRC 91C Tempera ture Controller This manual also contains troubleshooting and calibration procedures schematics component layouts and a complete parts list This se
49. Display Sensor 1 8 Display Sensor reading 80 DISP Control Sensor 5 10 17 Display Control Sensor Reading 90 DISP Set Point A 19 26 Display Set Point Reading 100 DISP Space a Line 110 OUTPUT 712 W1 A and B Input information 120 ENTER 712 5 Ask for string 1 130 DISP 1 5 Display string W1 140 DISP Space a Line 150 OUTPUT 712 w2 Interface Status 160 ENTER 712 A Ask for string W2 170 DISP W2 AS Display string W2 180 DISP Space a Line 190 OUTPUT 712 W3 Control Data Gain Reset etc 200 ENTER 712 AS Ask for string W3 210 DISP W3 5 Display string W3 220 DISP Gain A 1 3 Display Gain setting 230 DISP Rate AS 5 7 Display Rate setting 240 DISP Reset 5 9 11 Display Reset setting 250 DISP Heater Range 13 Heater Range 260 DISP Power 5 15 17 Power 270 DISP Space a Line 280 OUTPUT 712 WS Set for WS 290 ENTER 712 300 DISP WS AS 310 DISP 320 OUTPUT 712 330 ENTER 712 5 340 DISP WC 5 350 DISP 360 OUTPUT 712 370 ENTER 712 A 380 DISP WP 5 390 DISP 400 OUTPUT 712 WY 410 ENTER 712 5 420 DISP WY AS 430 DISP 440 OUTPUT 712 WI 450 ENTER 712 A 460 DISP WI 5 Ask for string WS Display Sensor Reading Space a Line Set for WC Ask for string WC Display Control Sensor Reading Space a Line Set for WP Ask for set point data Display string WP Space a Line Set for WY Ask for
50. Input Card Configurations 342 2 Single Input Card 3532 3 Dual Input Cards 3 2 4 Old Version Input Cards 33 CURVE ENTRY s V 7 RO WB SO 3 4 PRECISION OPTIONS d 3 4 1 Model 8000 Precision Option 3 4 2 Model 8001 Precision Option 3 4 3 The Model 8002 05 Precision Option 5 CONTROL FUNDAMENTALS a e 6 CONTROLS AND INDICATORS QJ gt The W50 and W60 Power Output Options Li 4 2 3 9 2 Current or Power Output Display ANH PO R PS NN FO hh NO P2 t 1 1 1 t d Ov Ov OY OY Ov OY OY Oy Ut Qi QI Wwf th SNO EB p S d F fF d d d t LJ LJ C3 UL GU UL LJ LJ C9 LY GJ NNN NM PO NO p PRR Ree pu TABLE OF CONTENTS cont d FRONT PANEL DESCRIPTION 3 7 POWER ON Bw lx 3 7 1 POWER UP Sequence o Ede 34452 POWER UP Status e e 3 8 DISPLAY SENSOR Block s as E DISPLAY SENSOR Input s s s s d d 8 4 8 2 8229 Scanner Conversion Option 8 3 SCAN Function 5 8 4 8 5 LJ LJ LJ LJ C9 LJ 2 gt 4 d RN The SCAN Dwell Time
51. OP AMP TSC914A 104 162 1 IC DISPLAY DRIVER MM5451N _ 104 355 5 IC OPTOCOUPLER 74016000 104 456 1 OPTOCOUPLER 74016010 104 453 1 IC 8 BIT A D CONVERTER ADCO831CCN 104 210 1 IC HEX INVERTER 7406 104 022 1 IC OP AMP JFET INPUT LF356N 102 104 1 POWER MOSFET 90V N CH VN0109N5 104 068 1 IC OP AMP DUAL MC1741 1458PI 102 095 1 POWER MOSFET 100 P CH IRF9130 CABLE MB TO U1 106 571 SOCKET TO 3 8080 1640 REPLACEABLE PARTS LIST DRC 91C LSCI Number 113 131 106 010 106 012 106 414 106 415 107 017 115 006 110 014 105 671 105 676 105 143 105 677 106 028 106 140 110 150 106 011 106 013 106 002 106 001 106 001 103 765 105 504 102 095 106 571 106 147 Part ed gt f gt gt A d gt 2 CONNECTOR KIT consisting of 5 PIN PLUG MATE TO J3 7 PIN PLUG MATE TO 45 16 PIN IDC SOCKET 16 PIN STRAIN RELIEF RMA INSERTS POWER CORD FUSE 1 0A SB 115 VAC 0 5A SB 250 VAC KEY TOP BLUE KEY TOP LIGHT GREY KNOBS KEY TOP MEDIUM GREY AC LINE CORD PLUG FUSE HOLDER LINE VLTG SLCTR CNNCTR J3 ON RB TO MB CONNECTOR TERMINALS CONNECTOR 5 PIN SOCKET CONNECTOR 7 PIN SOCKET HEATER HI OUT GRAY HEATER LO OUT BLACK HEATER GND BLACK POT 20 OHM 10 2 TAPER A B CONTROL SELECT POMER MOSFET 100V P CH SOCKET TO 3 TX1 TO MB 9
52. Range 0 to 3 V Resolution 0 05 millivolts Accuracy 0 1 millivolts Display Resolution 5 digits Displays 0 0000 to 2 9999 volts Equivalent temperature accuracy is a function of sensor type sensitivity and curve specifica tion or Precision Option 9210 6 Input Voltage Range 0 6 5535V Resolution 0 1 millivolts Accuracy 0 2 millivolts Display Resolution 5 digits displays 0 0000 to 6 5535 volts equivalent temperature accuracy is a function of sensor type and sensitivity Precision Option required for TG 120 Sensors 9210 1 9210 Diode Input Card 9210 4 INSTALLATION Ihe 9210 can be installed in the 91C 93C as either Input A or Input B or both with two options The 9210 is factory installed if ordered with DRC 91C 93C Temperature Controller or can be field installed at a later date If field installation is required use the following procedure 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and siide the panel Note on the calibration cover the position of the Input Card the 9210 will occupy WARNING TO prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment before removing cover 2 Remove the four screws that secure the calibration cover to its clips and remove the cover 3 If an Input Card must removed disconnect the wiring harness mating connector by liftin
53. Temperature Controll Front Panel in 3 5 9 O 9 19 15 Figure 3 1 Model DRC 91C enic Thermometer Front Panel Description Display Sensor 1 Display Sensor reading in temperature kelvin celsius or fahren heit or sensor units voltage resistance or Capacitance 25 Anning tated Display Sensor Selector Buttons with annunciated Scan on 3 Annunciators indicating units of Display Sensor Set Point 4 Display of Set Point in temperature kelvin celsius fahrenheit or sensor units voltage resistance or capacitance as indicated by Set Point Units ann nciators 5 Buttons which increment or decrement Units Set Point Dwell and where appropriate change sign of Set Point 6 Annunciators indicating units of Set Point Control 7 Annunciated CONTROL SENSOR indicator 8 Variable GAIN proportional control potentiometer 9 Variable RATE derivative control potentiometer 10 Variable RESET integral control potentiometer 11 HEATER CURRENT or HEATER POWER INDICATOR in percent of full scale 12 Full Scale selection of HEATER CURRENT or HEATER POWER for four orders of magnitude Includes output power OFF position 13 Return to LOCAL key with annunciator 14 REMOTE key with annunciator 15 POWER ON OFF switch COPYRIGHT 12 87 LSCI 3 3 Section III 2 Next the unit displays 91C in the upper display and indicates the IEEE 488 interface address in the lower display For a factory set IE
54. Type The first step to check the instru ment s display and operation is to determine the type of sensor input a The type of input option card s installed in the DRC 91C is located on the front page of every DRC 91C manual b The DRC 91C displays the type of input card s installed in the A and B inputs sequentially when the instrument is powered on Possibilities are 9210 3 9210 6 9215 30 9215 150 9220 3 9220 6 9220 P2 9220 3 9220 R1 9305 9317C or 9318C c The type of input can also be displayed by holding down the A B Display key 5 5 5 2 Check units display Verify that the A units can be changed by holding in the UNITS key and using the 44 or the vv to scroll through the sequence K C F V K etc Note the unit goes to V for a diode configuration 9210 3 6 or 9220 3 6 or for a resistance card configuration 9220 P2 P3 R1 or 9317C 9318C Input card 5 5 5 3 Check sensor units reading Next check to see if the instru ment is reading the correct sensor units volts ohms or nanofarads value for the appropriate test resistor or capacitor from Table 5 1 The reading should match the value given in the Display in Sen sor Units column of Table 5 1 The allowable error is provided in the Input A D Accuracy column 5 5 5 4 Check temperature reading Confirm that the temperature in kelvin displayed corresponds to the selected curve number COPYRIGHT 3 88 Section V a Check
55. V OUT 15 15 Figure 8225 1 Model 8225 Analog Output Option Model DRC 91C 93C 8229 Scanner Conversion Option 8229 SCANNER CONVERSION OPTION 8229 1 INTRODUCTION Table 8229 1 J9 8229 Scanner Conversion Option Connections This Section contains information pertaining to the Model 8229 Scanner Conversion for the DRC 91C 93C Temperature controller Channel Channel Included description Channel Channel specifications installation Channel Channel operation and maintenance Channel Channel information Channel Channel 8229 2 DESCRIPTION The 8229 Scanner Conversion is designed to be installed in a DRC 91 93 and additional channels of sensor input to Input A The 8229 inputs are designated Al through A4 and their selection is identified the display window at the left of the display With the 8229 installed the DRC 91C 93C is expanded from the standard dual sensor input to handle six input sensors The 8229 A1 through A4 channels can be selected directly using the SENSOR A key or included in the SCAN sequence independent Dwell time O to 99 seconds can be assigned to each of the additional inputs The A1 through A4 channeis of the Model 8229 Scanner are accessed through 24 pin Dp style connector located in the J9 Option Port the 91 93 rear panel Pin assignments for the connector are shown in Table 8229 1 The pin configuration for this connector is identical to th
56. ZN Command When EOI end or identify is enabled Z0 Table 4 6 the EOI line is set active concurrent with the last byte of a transfer Use of EOI identifies the last byte allowing for variable length data transmis sions EOI can be disabled 21 Table 4 6 4 7 2 Interface Mode Command the 4 7 2 1 Local This message Table 4 6 clears the remote opera tion of the DRC 91C and enables front panel operation Pressing the front panel LOCAL button also sets the instrument to local provided the button has not been disabled by the Local Lockout Message see Section 4 7 2 3 See Section 4 5 6 for a discussion of the DRC 91C under local operation while acting as a TALKER DRC 91C Summary of Output Requests 000 WI Input and Option Card Data ces wiser Scan Information Service Request mata Display Sensor Data Control Sensor Data Display Control Sensors and Set Point Data COPYRIGHT 3 88 LSCI Model DRC 91C Section IV Table 4 6 DRC 91C Interface Setup Commands and Request Status Functional Description Selects IEEE EOI status Forms of the command are ZO and Z1 When is EOI Status is 0 EOI line is set accepted on last character input or output EOI line is not set on last character output or acknowledged on input Selects Remote Interface mode Forms of the command are MO M1 and M2 When is Mode is 0 Local 1 Remote 2 Remote wi
57. and Operation Application Note Page 10 4 Measurement System Induced Errors In Diode Thermometry Article Reprint Page 14 FUNDAMENTALS FOR USAGE OF CRYOGENIC TEMPERATURE CONTROLLERS by Dr John M Swartz Lake Shore Cryotronics Lawrence G Rubin MIT National Magnet Laboratory 575 McCorkle Blvd Westerville OH 43082 170 Albany St Cambridge 02139 INTRODUCTION Cryogenic temperature controllers have been available for years but users often have an incomplete understanding of their operating principles and of the closed loop interactions between the controller and the controlled low temperature environment The object of this primer is to address this problem by presenting some fundamental and practical concepts of control at low temperatures The so called three mode PID controller utilizing Proportional gain Integral reset and Derivative rate functions will be discussed and examples given of its operation and adjustment While the emphasis will be placed on analog control systems the advantages and disadvantages of digital versus analog control will also be presented CHARACTERISTICS OF CRYOGENIC TEMPERATURE CONTROL SYSTEMS The adjective cryogenic as applied to temperature control systems defines a set of conditions that distinguishes such systems from those for which the great majority of applications exist i e industrial processes in which temper
58. and discon nect it from AC line power and all test equipment before re moving cover 2 Remove the four screws that secure the calibration cover to its clips and remove the cover Remove the two back panel 9215 73 9215 Capacitance Input Card mounting clips that secure the 711 blank cover plate to the interface opening and remove the plate Note some early DRC 91Cs do not have the J11 opening Use the J9 8229 Scanner option opening If an 8229 is present move the 8229 to the J10 RS 232 siot 3 If an Input Card must be removed disconnect the wiring harness mating connector by lifting the locking tab on the Input Card connector and qently pulling on the body of the wiring harness mating tor 4 Plug the new Input Card into the A Input Card Slot 5 or the Input Card Slot 6 with the component side to the left of the unit as viewed from the front Connect the wiring harness mating connector to the card making sure that the wiring harness locking tab is seated over the extended edge of the wiring harness mating connector Verify that the wiring harness is in place correctly by noting that the A or B on the harness mating connector is facing up if it is not review the harness installation again Thread the wiring harness along the rear edge of the unit and slip it into the harness strain relief the rear panel Thread the 9215 internal cable along the inside edge of the rear pane
59. at a later time A Precision Option Curve can have up to 97 points with two additional end points automatically put into the curve table by the DRC 91C software Up to 25 Precision tion Curves can be stored in the DRC 91C with an average of 31 points per curve Note For Lake Shore stored Ger manium and Carbon Glass Precision Option Curves a proprietary al gorithm is used to fit the cali bration data to within a few millikelvin over the entire temp erature range Section III Table 3 3 Sensor Curve Table Information Precision Option Table Crve Switch of Address Dscrptn No 45678 Lines 00 RESERVED ERR 09 3 10 SENSOR CURVE SELECTION 3 10 1 SENSOR ID Switch 4 Open 0 Ihe DRC 91C software interrogates the appropriate SENSOR ID switch i e A or B to determine which standard curve or Precision Option curve has been selected Switches 5 8 The SENSOR ID switch func tions are defined in Figure 2 3 3 8 Model DRC 91Cc The first sixteen curves 00 through 15 in Table 3 3 can be selected from the SENSOR ID switches 5 8 with switch number 4 off 3 10 1 1 Display of Accessed Curve To determine which curve you are using is a simple matter for the DRC 91C Select either the A or B input and depress and hold the LOCAL key After approximately one second the display will show the following format A 02 20 3 Since the HEATER display is now blank
60. be observed since the sensor temperature will continue to rise long after the output from the controller has been reduced to zero The obvious way to reduce this effect is to limit the heater power to the system to for example 0 5 watts This can readily be done with a controller such as the DRC 82C which has multiple maximum output power settings The overshoot will therefore be smaller when the set point is changed and the system will stabilize much faster although the rate of temperature rise will be less Because changing the power output setting affects the loop gain dP dT it may be necessary to readjust the deviation amplifier gain controller gain setting for optimum control It is normally good practice to determine the power requirements for one s system prior to or during the first experimental run Some system manufacturers may have that information available and may possibly supply a power load curve with the system Two other aspects of temperature control should be mentioned First ON Off controllers are frequently encountered at room temperature and above As the name implies such systems have only two states power on when the temperature is below the set point and off when it is above The proportional controller with excessive loop gain approximates this mode Although ON OFF controllers perform adequately with large furnaces for example they are generally unsatisfactory for cryogenic applications because of the relatively short t
61. between the A and B inputs with the A and B keys or automatically toggle between the two inputs by pressing the SCAN button for less than one second to initiate the scanning function 3 8 2 8229 Scanner Input Option With the addition of the Model 8229 Scanner Input Option four more inputs are added to the A channel input These additional inputs are designated 1 4 and their selec tion identified in the left side of the display window With the scanner conversion option present the SENSOR A button incre ments the inputs in the sequence 1 2 4 etc 8229 Scanner Input Option is covered Section VI of this manual 3 8 3 SCAN Function The SCAN function allows the in strument to step between the two inputs with a scan rate indepen dently set between O Skip and 99 seconds for each input If the scanner option is present inputs A1 A4 are included in the SCAN function and may each be set in dependently in their dwell scan time Setting a dwell time to zero automatically skips the channel only when in the SCAN mode 3 8 4 The SCAN Dwell Time The dwell time for each input can be displayed and changed by select ing an input for DISPLAY pressinq the SCAN key down for more than one second and using the 4 and v keys to increment or decrement the dis played dwell time for the input chosen similar result may be obtained by holding down the A or B COPYRIGHT 12 87 LSCI Model DR
62. current instrument status of the Sample Data Ready Example 2 Q2F All Status Reports with the SRQ bit off With the SRQ bit of the Status Register mask disabled no SRQ Table 4 13 Section IV interrupt by the DRC 91C will be generated however the BUS CON TROLLER can still read the Status Register and this command will give all five Status Reports Example 3 006000 1 Enable the Control Data Ready and Control Channel Limit with band of 0 1 about the control point 4 11 3 6 Status Register Mask at Power Up The Status Register Mask at power up is set to zero as is the Status Register DRC 91C Command Request Summary for Status Register Mask Functional Description The Status Register mask is set using the Q command Forms of the command are QOC5 02 2 04 2 Q6C5 and QC40 QC11 QC12 QC44 QC45 QC16 QC47 Status Register Mask is Error Overload Indicator Request OFF C1 C2 Service Request ON OFF ON Display Data X X X X A X X X SO Ut WN 1 SRQ Mask Data N4 8 Characters plus up to 2 terminators where C C5 COPYRIGHT 3 88 LSCI is the SRQ Mask Byte is the control channel limit band Section IV Model DRC 91C Figure 4 2 DRC 91C Status Register Mask and Status Register Format 4 1 gt 54 2 gt 7 6 5 4 3 2 1 Bit 8 4 2 1 8 4 2 1 lt We
63. designed to power a 25 ohm heater for maximum heater output a smaller resis tance is used the maximum heater power corresponds to the heater resistance i e 10 ohms yields 10 watts larger heater can also be used Since the compliance voltage is 25 volts a 50 ohm heater will allow a maximum power output of 12 5 watts 25 2 50 Two optional output power stages W50 and W60 of 50 and 60 watts respectively are available for the DRC 91C The W50 is rated at 1 ampere and 50 volts into 50 ohm COPYRIGHT 12 87 LSCI Model DRC 91C load while the W60 is rated at 1 5 amperes at approximately 43 volts into 25 ohm load A 50 ohm 50 watt 1 4 dia x 1 long cartridge heater is available as well as a 25 ohm 25 watt 3 8 dia x 1 long cartridge heater A 30 gauge stranded copper lead wire ND 30 is recommended for connecting to the heater 2 3 9 1 MAX HEATER POWER Limit Make sure that the MAX HEATER POWER limit potentiometer is turned fully clockwise during the setup of the instrument so that full power is available on the MAX power scale if desired Fully clockwise corre sponds to approximately 1 ampere while fully counterclockwise cor responds to the 1 range 330mA 2 3 9 2 Current or Power Output Display The HEATER meter can be set to read either of output power or of output current The internal DIP switch setting main board S7 switch 1 controls whether the meter reads in current
64. detent in shipping When the error occurs the unit displays dashes if it is the DISPLAY SENSOR input and continues operation until the fault is corrected The error is stored in the WI A Input data location and is displayed when the IOCAL key is pressed to determine the Input Card type Unrecognized B Input Card type Operation is the same for Err25 except the error is stored in the WI B Input data location Incorrect A Input Card polarity The 92xx Series Input Cards determine the input signal polarity doesn t match the temperature coefficient of the sensor type selected there is either an error in the sensor wiring an open circuit or a fault on the Input Card When the error occurs the unit displays the error if it is the DISPLAY SENSOR input and continues operation until the fault is corrected The error is stored in the WI A Input data location and is displayed when the LOCAL key is pressed to determine the Input Card type Incorrect B Input Card polarity Operation is the same as for Err27 except the error is stored in the WI B Input data location COPYRIGHT 5 88 3 Lake Shore Cryotronics Inc APPLICATION NOTES This appendix includes the following Lake Shore documentation 1 Fundamentals For Usage Of Cryogenic Temperature Controllers Application Note Page 1 2 Standard Curve 10 Technical Page 8 3 DT 470 Series Temperature Sensors Installation
65. error signal The amount of reset action can also be measured in repeats per minute or the number of times which the integrator can integrate between zero and full output in a time period of one minute for the constant proportional band error signal Thus if the time constant were say two minutes this is the same as saying that the reset circuitry repeats the proportional action in two minutes or 72 repeats per minute The term reset windup refers to a condition occurring in reset controller when an offset persists for a sufficiently long time The integration of the error with time will cause the integrator to saturate or windup at maximum output and remain so until the control point is traversed By the time this has happened a large overshoot may have occurred This problem can be prevented by disabling the reset action when controller response goes outside the proportional band A controller such as the DRC 82C accomplishes this with an anti reset windup or reset inhibit circuit 4 Application Notes Lake Shore Cryotronics Inc The Real World Revisited Since a real cryogenic system has non zero thermal resistance the value of the reset is important in setup of the controller The amount of reset desired is dependent on 1 the time required for the control sensor to reach equilibrium once it enters the proportional band and 2 the amount of output signal required from the reset action to overcome the cooling power of the cry
66. grease and other con taminants Use the following pro cedure 1 Clean the front and back panels and case with a soft cloth damp ened with a mild detergent and water solution Note DO NOT use aromatic hydrocarbons or chlorinated 501 vents to clean the DRC 91C They may react with the plastic mater ials used in the unit or the silk screen printing on the back panel 2 Clean the surface of the printed circuit boards PCB using clean dry air at low pressure If grease 15 encountered spray with Freon T F degreaser remove grime with dry low pres sure air 5 3 FUSE REPLACEMENT The line fuse is accessible from the rear of the DRC 91C Use the following procedure to check and or replace the fuse COPYRIGHT 3 88 To prevent shock hazard turn off instrument and disconnect it from AC line power and all test equipment before replacing the fuse 1 Set the POWER switch to OFF and disconnect the power cord from the unit The fuse compartment is located just to the right of the power connector 2 Open the fuse compartment by prying open the cover with a small screw driver 3 Remove the lower fuse holder by sliding it out of its position with the aid of the small screw driver CAUTION For continued protection against fire hazard replace only with the same type and rating of fuse as specified for the line for the line voltage selected 4 Replace the fuse per Table 2 1 5 Re
67. is held down for over 1 second the rate at which the set point changes is increased by a factor of five If in degrees celsius or degrees fahrenheit the button can be used to toggle the sign of the set point The set point is limited in tem perature to the range of the curve stored in the instrument Table 3 2 gives these limitations in kelvin for curves 00 through 04 3 11 2 GAIN Variable gain pro portional allows adjustment of overall controller gain over a 1000 to i range Maximum gain is full clockwise Logarithmic scaling is used Therefore a gain setting of X100 is approximately two thirds of full rotation 3 11 3 RATE Adjusts rate time constant of differentiator Effectively sets time constant between 1000 seconds and 1 second with full clockwise rotation repre senting the shortest time constant or between 0 001 and 1 beat s per COPYRIGHT 12 87 LSCI Model DRC 91Cc second BPS For a discussion of beats per second time constants see the Application Note enclosed as an Appendix to this manual 3 11 4 RESET Adjusts reset integral time constant of tegrator Effectively sets time constant between 1000 seconds and 1 second with full clockwise rotation representing the shortest time con stant Reset and Rate Times Figure 3 3 for 91C 3 11 5 HEATER Displays the magnitude of the heater power in percent of full scale Full scale is defined as the product of the maxi
68. line Section III 3 4 PRECISION OPTIONS 3 4 1 The Option There are three types of Precision Options available for the DRC 91C The Model 8000 Precision Option generates the data table from a Lake Shore calibrated sensor The upper limit of data points is again 99 with typical calibration ranging between 30 and 40 points depending on sensor type and temp erature range for the calibration The data and accuracy of the fit is supplied to the user as a separate document This information then be entered by the user over the computer interface Model 8000 Precision 3 4 2 The Model 8001 Precision Option Lake Shore can also generate custom sensor response curves from the in dividual sensor calibrations as indicated above and store them in the DRC 91C via the 8001 Precision Option prior to shipment The data and accuracy of the fit is then supplied to the user as a Appendix to this manual 3 4 3 The Model 8002 05 Precision Option The 8002 Precision Option is used when the customer already owns a DRC 91C and wants new sensor cali bration data stored in the instru ment LSCI stores the calibration data in a NOVRAM and sends the programmed chip to the customer The PROM is then installed in the DRC 91C by the customer Note that additional calibrations can be added to the instrument at a later time by specifying with the sensor calibration time of order the serial number of the instrument an
69. materials mentioned which are used in sensor installation are available from Lake Shore Cryotronics Inc References Krause J K and Swinehart P R 1985 Demystifying Cryogenic Temperature Sensors Photonics Spectra August 61 68 Available on request from Lake Shore Cryotronics Inc Krause J K and Dodrill B C 1986 Measurement System Induced Errors in Diode Thermometry Review of Scientific Instruments 57 4 661 665 Available on request from Lake Shore Cryotronics Inc Sparks L L 1983 Temperature Strain and Magnetic Field Measurements In Materials at Low Temperatures Ed By R P Reed and A F Clark American Society of Metals Metals Park 515 571 White G K 1979 Experimental Techniques in Low Temperature Physics Clarendon Press Oxford Application Notes 13 Lake Shore Cryotronics Inc MEASUREMENT SYSTEM INDUCED ERRORS IN DIODE THERMOMETRY by John K Krause and Brad C Dodrill Diode temperature sensors are capable of being used at the accuracy level of a few hundredths of a kelvin However in order to achieve this performance proper measurement techniques must be used Poorly shielded or improperly grounded measurement systems can introduce ac noise which will create an apparent shift in the dc voltage reading across a diode sensor This results in a temperature measurement error which may approach several tenths of a kelvin The presence of the ac noise in question is not obvious during normal
70. may require the removal of a plastic cover plate If the JF mating connector on the main board interferes with installation of the Terminal Block remove it by lifting the locking tab and gently pulling the body of the connector sure to lock the JF mating COPYRIGHT 6 88 LSCI 5 6 9305 Thermocouple Input Card 9305 Thermocouple Input Card Temperature Ranges Thermocouple Type Compensated Uncompensated Chromel vs Au 0 03 connector securely place after this step is complete Connect the wiring harness from the Terminal Block to the bottom Connector on the 9305 Card Also connect the J1 Input or J2 Input B wiring harness mating connector to the top P2 Connector on the 9305 Card Make sure that the wiring harness locking tab is seated over the extended edge of the wiring harness mating connector Plug the 9305 into the appropriate Input Card Slot with the component side facing to the left of the unit as Viewed from the front Make sure the card is thoroughly seated Verify that the wiring harness is in place correctly by noting that the A or p on the harness connector is facing up if it is not review the harness installation again Replace the calibration cover making sure to align the cards so that their respective 9305 3 9305 Thermocouple Input Card adjustment trimpots are accessible through the cover Place the cover on top of the cover clip
71. operate properly the sign of the voltage must reflect the tempera ture coefficient of the sensor It is necessary for the user to determine which range the sensor is in and to inform the controller of the sign of the temperature coefficient This is accomplished on the DRC 91C by a switch switch l of the SENSOR ID on its rear COPYRIGHT 2 88 LSCI Model DRC 91C 93C panel and on the DRC 93C by a sequence of key strokes from its front panel Also the Sign of the temperature coefficient entered via the computer interface using the 1 or command 9215 6 1 Selection of Temperature Coefficient Sign on the DRC 91C The sign to be used on the Tempera ture Coefficient of the capacitance is selected using Switch 1 of the appropriate SENSOR ID located on the rear panel of the DRC 91C When Switch 1 of the SENSOR ID is closed the Temperature Coefficient is Positive When Switch 1 of the SENSOR ID is open the Temperature Coefficient is Negative 9215 6 2 Selection of Temperature Coefficient Sign on the DRC 93C When a 9215 Capacitance Input Card is installed pressing the SENSOR key will display for the propriate channel either 15 15 or 15 50 the 15 for the 9215 15 configuration or 50 for the 9215 150 configuration The sign indicates whether the Temperature Coefficient is positive or nega tive The plus means that the Temperature Coefficient is posi tive The minus means th
72. over their respective temperature ranges The thermocouple voltage is amplified by 100 by a circuit which is attached to the Terminal Block Ihe thermocouple voltage is further amplified by factor of 2 tunable by the Control Amplifier on the 9305 Thermocouple Input Card The amplified signal is sent to the main board analog control circuitry and can be accessed from the Buffered Output line of the 03 Monitor Connector on the controllers back panel In addition the amplified thermocouple voltage is applied to a 15 bit A D converter on the Thermocouple Input Card so that digitized thermocouple voltage can be sent to the main board microprocessor Ihe Thermocouple A D converter has auto zero function which means that the only calibration required is for the relative gain A secondary diode temperature sensor is attached to the Terminal Block to monitor the reference junction temperature needed for Reference Junction Compensation A constant current source on the 9305 is applied to the Secondary Sensor A 15 bit A D converter on the 29305 Card digitizes the secondary sensor voltage and sends the data to the main board microprocessor The microprocessor on the main board of the controller calculates the reference junction temperature The reference junction temperature is used in compensation to account for the difference between room temperature and the normalization temperature of the curves zero
73. point resistance and is determined with the individual card calibration constants there is no way to enter a set point that results in a pre determined value for the set point The Internal ID Switch S7 on the Main Board is used in the calibration Note the position of the Internal ID switches before proceeding Attach the plus and minus leads of the DVM to TP25 SP V and TP1 GND 2s respectively of the Calibration and Service Card Make switch 7 CLOSED ON This forces the unit to output a set point of 0 volts Adjust the SP ZERO ADJ trimpot until the DVM reads as close to zero as possible Turn switch 6 of the Internal ID This forces the unit to output a set point of 2 7 volts Adjust the SP SPAN ADJ trimpot until the DVM reads as close to 2 7000 volts as possible This procedure should be done until the 0 and 2 7 readings are as close as possible to the calibration values Before returning to normal operation make sure switches 7 and 6 of the Internal ID are OPEN OFF Replace the calibration cover and then the top cover 9317C 9318C 7 9317C 9318C Input Cards Table 9317C 9318C 2 Calibration Switch Definitions Viewed from the Component Side of 9317C 9318C Micro LI of PCB Viewed through Calibration Cover Model 91 93 9317C 9318C 8 SENSOR CURVE INFORMATION The curves used with the 9317C 9318C Input Card are generat ed using a proprietary Polynomial Interpolatio
74. poles make before break 2 voltage poles break before make Maximum Input Voltage 32 volts DC or peak AC Maximum Current 10 milliamperes Thermal Offset Less than 3 micro volts per contact on break before make poles less than 50 microvolts on others Contact Resistance Less than 19 Open Channel Isolation gt 1019 ohms Input Output 24 pin D style connector mate supplied Channel Selection Front panel SENSOR key increments 0 1 A2 A3 A4 AO etc each time it is pressed or automatically in the SCAN mode All front panel operations can be duplicated over the remote interfaces Switch Contact Life gt 10 operations at rated load Configuration Channels 0 through A4 are confiqured as Remote Position A00 through 04 with respect to Sensor Curve selection with 8229 present Channel Selected Data Chnnl selected present in BCD form on J9 connector 8229 4 INSTALLATTON The 8229 Scanner Conversion is factory installed if ordered with an DRC 91C Temperature Controller 8229 2 Model DRC 91C 93cC or can be field installed at a later date If field installation is required use the following procedure WARNING To prevent shock hazard turn off instrument and disconnect it from AC line power and all test equip ment before removing cover 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off
75. power dissipation magnetic field dependence and temperature range In the less common case of cryogenic thermocouples the very low sensitivity 10uV K requires quite large pre amplifier gains and a stable reference junction arrangement Thermocouples are sometimes used when sensor size or time response are more important than temperature stability and accuracy At cryogenic temperatures thermocouple accuracy does not approach that of a semiconductor diode or resistance thermometer when either are properly installed Vil ANALOG VERSUS DIGITAL CONTROL In this day of computers designing digital instrumentation with a microprocessor is definitely in vogue In a digital control system the sensor voltage is digitized by an analog to digital AD converter The digitized temperature is then compared to the digital set point within the microprocessor and by means of an appropriate algorithm the average power to the heater is adjusted A converter with a 14 bit resolution 1 part in 16 384 enables the microprocessor to determine the temperature to approximately 4 mK at 4 2 kelvin using the diode sensor of Figure 2 In a system which is inherently stable the control temperature stability can be no better than the temperature resolution of the AD converter 4 mK for this example Cost effective AD converters with such resolution have sampling times in the half second range In the world of ovens furnaces and other large industrial processes which operat
76. the Capacitance Input Card 5 Adjust the trimpot marked A D until the display reads 15 000nF for the 9215 15 or 75 00nF for the 9215 150 Check linearity by inputting 2 0000 and 1 0000 COPYRIGHT 2 88 LSCI Model DRC 91C 93C volts and verify that the unit displays 20 000 10 000nF within 0 001nF for the 9215 15 or 100 0 and 50 0nF within 0 01nF for the 9215 150 6 Return 51 Switch 2 to the CLOSED 1 position 9215 8 2 Zero Calibration 1 Be sure that the leads are in the configuration which will be used in your system Detach the capacitance sensor 2 Verify that the Display indi cates the Capacitance Input Card 3 Adjust the trimpot marked ZERO so that the display reads 0 000 on the 9215 15 or 0 00 on the 9215 150 9215 8 3 Span Calibration 1 Be sure that the leads are in the configuration which will be used in your system Attach the standard capacitor in place of the capacitance sensor 2 Verify that the Display indi cates the Capacitance Input Card 3 Adjust the trimpot marked SPAN so that the display reads the value of the standard capacitor 9215 9 REPLACEABLE PARTS Included in this section is Figure 9215 1 It includes the Model 9215 Capacitance Input Schematics replaceable parts list and 11 lustrated component layout Refer to the manual for ordering informa tion COPYRIGHT 2 88 LSCI 9215 Capacitance Input Card 9215 7 T ITEM NO
77. the Sensor Curve Table Table 3 2 or below to deter mine the curve number that selects the standard curve or precision option that is needed A 9215 card will not read temp erature The 9317C 9318C will not read accurately temp erature unless a precision option is present b Select the curve as described in Section 3 9 5 5 5 5 Check Input B Change the connector from J1 INPUT A to J2 INPUT B Repeat the above process by verifying the current source and the A D settings for this input as well as the units change 5 5 6 Heater Output Test 5 5 6 1 Heater Output Conditions The heater should output power when the setpoint temperature is above the display temperature as long as the heater is on and a gain value has been entered If the sensor is a diode the voltage across the device will change inversely with temperature Therefore the higher the voltage the lower the tempera ture For Platinum sensors the resistance increases as the temper ature increases Germanium and carbon glass sensors are negative temperature coefficient resistance sensors which vary several orders of magnitude resistance with temperature 5 3 Section V 5 5 6 2 Test Setup Test the heat er by placing an appropriate test resistor see Table 5 1 into the control sensor input and place a 10 ohm at least 10 watts up to 50 ohm at least 50 watts resistor across the heater terminals 5 5 6 3 The Heater Display The he
78. the enabled disabled status of the upper display press the key Similarly to change the sign of the lower display press the vv key 4 Release the or vv then the SCAN 1 key key 5 Press the SENSOR key to verify that the proper sign is selected 9317C 9318C 4 Model DRC 91C 93C 9317C 9318C 5 3 Sample Input When the input occupied by the 9317C 9318C is selected as the sample Input Sample only not Control the 9317C 9318C deter mines the sample resistance by forcing the voltage across the sensor to 1 05 9317 or 10 5 9318C millivolts as quickly as possible with the microprocessor controlled current source Once the forward current range and value results in the desired voltage the current is reversed and the thermal value determined As long as the voltage across the sensor does not change more than 0 5 of reading from one reading to the next the forward and reverse readings are taken each time the input card is asked for an update approximately once a second and a new thermal value is determined If the voltage changes more than 0 5 of reading the card stops reversing the current and uses the thermal value previously determined until the sensor signal stabilizes Operation as the 9317C 9318C 5 4 Control Input Operation as the When the input occupied by the 9317C 9318C is selected as the Control Input Control only Sample and Control the operation of the card changes
79. the shortest for higher settings Next turn the reset off and make sure that the reading returns to 0 0 volts 5 5 7 3 Rate The operation of the Rate can not be observed without measuring voltages in the unit To check the RATE move the DVM HI lead to TP31 keep the GAIN at 10 turn the RESET off 0 0 and enter a RATE to 99 The DVM should read 0 0 volts Quickly change the set point value from approximately equal to the display value to a value 20 higher equivalent kelvin temperature e g from 1 00 volts to 0 80 volts The DVM should show a positive transient whose peak value will lie between 0 1 and 7 volts depending on the rate at which you change the set point the amount of gain the speed at which you change the volt age as well as when the reading is read by the DVM For the change from be negative in value The GAIN RATE and RESET values are summed together before the heater drive circuit with the GAIN being multiplied by two signal strength before summation The sum of the three terms can be measured at TP28 ANA OUT 5 5 8 Checking the Heater Ranges 5 5 8 1 Standard 25 Watt output Set up the unit so that 100 percent is output to the heater load At full power out on the Max scale 1 amp should be through the resistor as long as the resistor is 25 ohms or less The heater circuit has a compliance voltage limit of 25 volts so a resistor larger than 25 ohms will limit the current to 25 div
80. the software interpolation accuracy and the Calculation of the resistance results in an overall accuracy on the order of 10mK These input option cards are easily installed by the user thus units can be changed or upgraded satisfy changing requirements The ample memory space provided in the DRC 91C allows several response curves to be stored in the instru ment Depending on the complexity of the curves up to 25 can be programmed into the unit A rear panel DIP switch Sensor ID is used to select the particular sensor response curve for each input The data for calibrated sensors can be stored in the instrument as an 8001 Precision Option or by the customer via the IEEE 488 inter face These curves can contain up to 99 sensor temperature data points With the standard preci sion option format of 31 data points and an 18 character informa tion line up to twenty curves can be stored Although data points are stored as a table the interpolation 1 gorithm used results the equivalent of a high order Cheby chev polynomial calculation in the converting of the input voltage COPYRIGHT 1 88 LSCI Model DRC 91C or resistance to temperature This is done by means of propri etary algorithm developed at Lake Shore Cryotronics An averaging algorithm be selected to average up to ten temperature readings This mode eliminates noise within the system analogous to averaging with a digital voltm
81. together The CO assembly should appear as shown in the accompanying drawings Bolt the assembly into a 4 40 threaded hole The stop on the brass screw should rest against the mounting surface and it also prevents over compressing the spring Lift the edge of the clip using a small pliers or screw driver Slide the SD package into place underneath the clip and gently lower the clip onto the lid of the SD package Note that a slot is cut underneath the clip to accept the SD package Refer to the drawing for details If the device is to be used only below 325 K apply a layer of Apiezon N Grease between the SD package and mounting surface to enhance thermal contact 12 SD Sensor Beryllium Oxide Heat Sink Chip 2 95 mm diameter for 4 40 machine Cathode Anode 4 40 shoulder screw extends 6 9 mm above clamp Application Notes Lake Shore Cryotronics Inc Sensor Current Source V FIGURE 1 Four Wire Configuration for DT 470 Installation SENSOR OPERATION Temperature controllers and thermometer instrumentation manufactured by Lake Shore Cryotronics are designed to be directly compatible with the DT 470 sensor to give optimum performance and accuracy together with direct temperature readouts Simply follow the instructions provided with the instrument concerning sensor connection and instrument operation If a user supplied current source voltmeter or other instrumentation are going to use
82. when all 32 Curves are present plus up to 2 Terminators where N NoN3N the decimal number of curve locations available BYTES FREE 2 4 is the Hex address the next curve will start at 1 2 is the Sensor Curve assigned to Remote Position A00 through and BOO through BIF Table 4 18 MIENNE MENSEM Sensor Curve Output Format C1o N4NA C X XXXXX X XXXXX A minimum of 54 Characters for a curve with the minimum of 2 data points and a maximum of 1412 Characters for a curve the maximum of 97 data points plus up to 2 Terminators where 1 2 is the Sensor Curve number 00 thru 31 1 18 is the 18 Character Information line C19 is the Temperature Coefficient P or N is the number of data points 00 thru 99 X XXXXX is the Voltage Equivalent V or Log R TTT T is the Temperature to 0 1 only COPYRIGHT 3 88 LSCI 4 29 Section IV 10 Program to output Curve Table 20 DIM Curve 462 30 OUTPUT 720 XDOO 40 ENTER 720 50 REM Display Curve Title Temperature 60 REM Coefficient and Number of Breakpoints 70 DISP Curve 1 27 80 REM Display voltage and temp data points 90 1 238 100 DISP CurveS I I 41 Temp 110 IF 447 THEN 140 I 477 for D Pnt 31 120 1 1 42 130 GOTO 100 140 DISP 5 448 460 150 END Voltage Note that th
83. with annunciators F shown Resolution Display resolution is 0 001K below 100K 0 01K above 100K 0 0001K below 10K for 9317 Resistance Sensor Input Card Resolution can be user limited to 1K 0 1K or 0 01K Same resolution considerations apply for C F and Sensor Units Changes made by front panel keys or over interface Temperature Accuracy Dependent on Sensor Input Card and Sensor See Input Options available ture Range Dependent of Sensor Input Card and Sensor Temperature Control Set Point Button increment either fast or slow of set point in set point units Set Point Resolution Selection in kelvin celsius fahrenheit or Sensor Units Temperature to 0 1 in corresponding units in Sensor Units 0 1mV in voltage 0 01 ohms but limited to five digits in resistance and 0 001 nanofarads out of 15 nanofarads 0 01 nanofarads out of 150 nanofarads for second scale in capacitance May also be set over the interface COPYRIGHT 1 88 LSCI Model DRC 91C Typical Controllability Dependent on Sensor its temperature and the resultant Sensor gain i e sensitivity Typically better than 0 001K in a properly designed system below 30K and 10mK above 30K using a Diode Sensor But for example a thermistor due to its large sensitivity may result in a controllability approaching 0 5mK above 200K over a narrow tempera ture range in certain systems and a germanium below 10K may control to O 1mK in an
84. 000 112 39000 216 25553 218 01000 219 78000 221 55000 223 31000 225 07000 226 83000 228 59000 230 34000 232 10593 23 52499 233 84000 25 67000 235 57000 27 82000 237 31000 29 95000 239 06000 32 08087 240 79000 34 16000 242 52000 36 25000 244 25000 38 34000 245 97000 40 42000 247 71350 42 49000 249 42000 85 0 90 0 95 0 100 0 105 0 110 0 115 0 120 0 125 0 0 APPENDIX B Sensor Curve 18 Character Information Line Reserved Character Definitions Each Sensor Curve has an 18 character information line Some of the characters are reserved for specific operations The definitions are as follows Curve type L Unit performs Lagrangian calculations on the data Any other character Unit performs Straight Line interpolation on the data Temperature Range Setpoint Limit 0 Up to 324 9 1 Up to 374 9 K 2 Up to 474 9 K 3 Up to 799 9 K 4 Up to 999 9 K Sensor type used for front panel curve entry here alphanumerics cannot be entered with the standard numeric keypad 0 DI 470 Series Silicon Diode Sensors 1 DT 500 Silicon Diode Sensors 2 TG 100 TG 200GaAs and GaA As 3 100 Ohm Platinum Resistance Thermometers PRT s 4 1000 Ohm Platinum Resistance Thermometers PRT s 5 Rhodium Iron Resistance Sensors 6 Ge
85. 12 0 00 0 1 to 0 01 0 01 0 01 to 0 001 0 1 0 001 to 0 0001 0 0001 to 0 00001 AR R 1 R 4R R Note 1 input resolution is 0 05 millivolts for the 9210 9220 3 and is 0 1 millivolts for the 9210 9220 6 Note 2 This assumes an ability to resolve between 1 part in 104 and 1 part in 10 where varies between 1074 and 10 3 6 COPYRIGHT 12 87 LSCI Model DRC 91C necessarily accuracy of the read ing Also note that if the sen sitivity of the sensor is too low to support this resolution i e one bit corresponds to greater than the above resolution some tempera tures may be skipped This will be true for a silicon diode sensor between 30 kelvin and 100 kelvin where the sensitivity is approx imately 2 5 millivolts per kelvin and the voltage resolution is 0 05 millivolts For this case the resulting temperature resolution is 0 05 2 5 0 02 kelvin However below 30 kelvin the silicon diode sensitivity is approximately 25 millivolts per kelvin which results in an approximate resolution of 0 002 kelvin 0 05 25 3 8 7 Filtering the Display An averaging algorithm within the instrument is available which averages up to ten readings This reading mode eliminates noise with in the cryogenic system analogous to averaging within a digital volt meter This function selected or deselected by switch 2 of the SENSOR ID on the back panel for each input separately The DRC 9
86. 1C is shipped from the factory with the filtering function Selected for both inputs The decimal point on the sign digit at the far left of the display win dow flags Filter on will indicate whether the averaging 1 gorithm is being used for that input The averaging algorithm is a moving average in that when a A D reading is taken the new reading replaces the oldest reading and the new average is displayed If the averaging algorithm is used dis played temperature is on the aver age somewhere between 1 and ten readings depending on the tempera ture variation If an abrupt change in temperature is observed averaging is disabled and the last calculated reading displayed As the disturbance is reduced in COPYRIGHT 12 87 LSCI Section III value the averaging gradually increases until a total of ten readings are considered 3 9 SENSOR CURVES 3 9 1 Standard Curves The standard curves with their curve number temperature range and SENSOR ID switch position are given in Table 3 2 Table 3 2 Standard Curve Information Switch oe 2e Temperature Curve pee 3 9 2 The Precision Option Table Table 3 3 gives the standard curves present in the DRC 91C as well as any Precision Options which are factory installed including their address the number of data points associated with each curve This Table should be updated for the instrument if additional curves are added
87. 337 0 34881 0 32416 0 29941 0 27456 0 24963 0 22463 0 19961 0 17464 0 14985 0 12547 0 10191 0 09062 Lighter numbers indicate truncated portion of Standard Curve 10 corresponding to the reduced temperature range of DT 471 diode sensors The 1 4 325 K portion of Curve 10 is applicable to the DT 450 miniature silicon diode sensor 8 Application Notes Lake Shore Cryotronics Inc POLYNOMIAL REPRESENTATION Curve 10 can be expressed by a polynomial equation based on the Chebychev polynomials Four separate ranges are required to accurately describe the curve Table 1 lists the parameters for these ranges The polynomials represent Curve 10 on the preceding page with RMS deviations of 10 mK The Chebychev equation is T x at x 1 0 where T x temperature in kelvin amp Chebychev polynomial and the Chebychev coefficient parameter x is V VL VU V VU VL where V voltage and VL VU lower and upper limit of the voltage over the fit range The Chebychev polynomials can X 2xt ha X be generated from the recursion relation 3 x 1 4 Alternately these polynomials given by t x cos ixarccos 4 2 a normalized variable given by The use of Chebychev polynomials is no more complicated than the use of the regular power series and they offer significant advantages in the actual fitting process The first step is to transfo
88. 5 OPERATION 8229 Scanner implemented Operation of the Conversion can be either locally from the front panel or remotely through the remote interfaces 8229 5 1 Local 8229 Operation The 8229 A1 through A4 channels are accessed locally using the SENSOR A key The Display Sensor is incremented each time the SENSOR A key is pressed in the sequence A Al A2 A3 A4 A etc 8229 5 1 1 Channel Dwell Times The dwell times for the 1 through A4 channels are selected the same as for and B See Sections 3 8 3 and 3 8 4 for complete description of this operation 8229 5 1 2 Units The units for the A1 through A4 channeis are the same as for Input and are defined by the A Input Card Selection units 165 covered in Section 3 8 5 8229 5 1 3 Resolution Resolution is by input card and not channel Consequently resolution 15 the same for all scanner COPYRIGHT 12 87 LSCI 8229 Scanner Conversion Option channels See Section 3 8 6 for a discussion of how to set resolution 8229 5 2 Remote 8229 Operation The remote operation of the 8229 Scanner is covered in Section 4 REMOTE OPERATION See Table 4 7 and Section 4 11 entitled THE OPTIONAL SCANNER CARD 8229 5 3 Curve Selection The 8229 is considered an internal Remote Position The AO through A4 channels are interpreted as Remote Position 00 through A04 for curve selection when the SENSOR ID Switch 4 is OPEN 0 The curve for the input i
89. 610 1 8390 1 30422 1 6984 1 7769 1 28527 25 1 6359 1 7148 1 26702 1 5646 24 1 5527 1 24928 1 4932 1 5724 1 23184 1 4219 1 4922 1 21555 1 19645 1 17705 1 15558 22 1 13598 1 12463 1 11896 1 1486 1 1559 20 1 1308 19 1 1365 19 1 11517 1 1190 18 1 1239 18 1 11202 18 1 1116 17 1 1150 1 10945 1 1058 16 1 1080 1 10702 1 10465 16 1 0970 1 10263 15 1 0902 1 09864 1 0850 l6 1 09477 1 0798 1 09131 1 0746 1 08781 1 08105 1 0633 1 0630 1 0520 1 0515 1 07053 13 1 0407 1 0399 1 0287 11 1 0284 14 12095277 1 0166 1 0159 1 04353 1 0046 1 0035 1 03425 0 9911 0 9849 1 02482 13 1 02044 0 9780 1 01525 0 9649 1 00552 0 9518 99565 0 9388 12 98574 0 9257 97550 0 9122 0 8988 0 8853 0 8718 0 8584 0 8449 0 8311 0 8173 0 8035 0 7896 0 7758 0 7620 0 7482 7 0 7344 0 7202 0 7060 0 6918 0 6777 0 6635 0 6493 0 6351 0 6210 0 6068 6 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 APPENDIX A DIN Standard Curve for 100 ohm Platinum Sensors 94 83000 96 80000 98 78433 100 72000 102 67000 104 62000 106 57000 108 51000 110 45
90. 80 51 5 HCPL 2731 LTC1043 DAC703BH 5 2 1 13202 TSC500CPE CD4020BCN 79105 27 64 3 5 000MHZ ck Eae ui 27 _ LPLUGCED IN J Pit PLD 1 Ar Pig 6 50 23383288 ON uis DETAIL BOTTOM VIEW 195 DATA IN RAKE SHORE CRYOTRONICS nme 9318 RESISTANCE OPTION CARD 7 Figure 9318 1 Model 9318C Resistance Input Card Model DRC 91C 93C Model 8223 RS 232C Interface MODEL 8223 RS 232C INTERFACE 8223 1 INTRODUCTION This Section contains information pertaining to the Model 8223 RS 232C Interface for the DRC 91C 93C Temperature Controller Included is a description Specifications installation operation and maintenance information 8223 2 DESCRIPTION The 8223 RS 232C Interface is designed to be installed in a DRC 91C 93C and provide an interface with an external 5 232 instrument such as a computer modem or CRT The interface operates in a half duplex mode it can only transmit and receive information direction at a time and data transmission is asynchronous each character is bracketed by start and stop bits that separate a
91. 8223 Interface when shipped none of the switches on the 8223 board need to be changed When connecting the HP 86B Serial Interface to the 8223 Interface a transition cable needs to be made to connect the socket connector of the HP to the socket connector of the 8223 Interface Figure 8223 3 shows the adapter cable that must Duplex with Handshake Figure 8223 4 shows the adapter cable for Half Duplex with handshake communications with an HP 86B Serial Interface The arrows indicate the source direction of signal flow Figure 8223 4 Half Duplex with Handshake Connector to HP 86B be made The arrows indicate the Protective Protective source and direction of signal Ground Ground flow Transmitted Transmitted Data Data Figure 8223 3 Half Duplex W O Received Received Handshake Data Data Request to Request to Connection to HP 86B Send Send Clear to Send Send Data Set Data Set Ready Ready Signal Signal Ground Ground Carrier Carrier petect Detect Data Data Terminal Terminal Ready Ready Clear to Protective Ground Protective Ground Transmitted Data Received Data Signal Ground following program will input DRC 91C 93C command from the keyboard and Computer 8223 6 COPYRIGHT 12 87 LSCI Line Signal Model DRC 91C 93C The Auto Handshake capability of the HP 86B Serial Interface must be enabled The addition of the program line 16 CONTROL DSR DCD CTS 10 2 7 E
92. 91 nau I EEBRBDLHI V E A A R E A A ae V TERRY 7110 E E MEME 7 a ee i ee S ee ao ee RNS 4 75 8 9 1 6 28 2199 9 0000000 1 X a DRC O1C MAINOOARD 2 1 o o o o o o o Q 9 DIGITAL SECTION 2 5 es NY DI EM 4544 4 69 18 24 Figure 91C 1d Schematic DRC 91C Main Board 3 Digital Section 8 7 6 5 4 3 2 1 SLOT 6 SOTS B CHANNEL A CHANNEL SLOT 4 ANALOG INPUT ANALOG INPUT CALIBRATION AND Figure 91C 1e Schematic DRC 91C Main Board 4 interconnections CARD CARD SERVICE CARD GND A s 15 GND 5 15 A PWR V GND A 15V CS 9 15 15V 15 PMR VREF HTR REF gv cS B CS B BV CS A Ve CS A V CS HTR DRV B VIN B A D IN A A D 12 CS PWR LOW JB CS B HTR V Moe CS B GND DISPLAY BOARD PWR V ADJ CONNECTOR 15 A 15 A F V GAIN V B DATA OUT A DATA OUT CNT V X GND ED GND Ald GND Ald AN OUT 8 A ADE GND ET GND Add 15 A 8 A 404 5 A 5 A 5 A 5 A V 5 A 45 A 5 A 5 5 AD 15 A 15 A 15 A 15 A 15 A SP SPAN ADJ _ CS
93. 91C 93C 9215 Capacitance Input Card 9215 CAPACITANCE INPUT CARD OPTION 9215 1 INTRODUCTION This section contains information pertaining to the Model 9215 15 9215 150 Capacitance Input Card Configurations Specifications installation and operating instruc tions a description of the principle of operation and maintenance information are included Section 9215 3 describes some characteristics of Capacitance sensors 9215 2 DESCRIPTION AND SPECIFI CATIONS The Model 9215 Capacitance Input Card is designed to be installed in a DRC 91C or DRC 93C to convert either Input A or Input B to accommodate Capacitance sensors When used to control temperature in magnetic fields the capacitance sensor is superior to other sensors since the displacement current in a capacitor is magnetic independent Accurate temperature reading requires the use of another type of sensor in zero magnetic field This accurate sensor can be placed in the other Input Slot of the DRC 91C DRC 93C The 9215 15 configuration is used with Capacitance sensors with a maximum of 30 nanofarads for example Lake Shore CS 401 Series Sensors The 9215 150 configuration will accommodate Capacitance sensors of up to 150 nanofarads for example Lake Shore CS 501 Series The card can be configured by the user as either a 15 nanofard 9215 15 or a 150 nanofarad 9215 150 card by switches on the card Specifications for the Model 9215 COPYRIGH
94. 91C 93C harness mating connector is facing up if it is not review the harness installation again Thread the wiring harness along the rear edge of the unit and slip it into the harness strain relief on the rear panel 5 Install the calibration cover by reversing procedure 2 6 Install the top panel 9220 5 OPERATION The 9220 3 9220 65 configurations are equivalent to the 9210 3 9210 6 configurations terms of operation The Model 9220 P2 Configuration provides the 1 milliampere excitation current to the platinum sensor the 9220 P3 supplies 0 1 milliampere the 9220 R1 supplies 3 milliamperes The resulting sensor voltage is amplified factor of 10 negative 10 and digitized a 16 bit A D converter with a resolution of better than 100 microvolts out of 3 0000 volts full scale The digitized value is converted to a serial data string and transferred to the main microprocessor using optical isolation The amplified 7 10 sensor voltage is transferred to the J3 MONITORS connector for external monitoring 9220 6 CALIBRATION The 9220 was calibrated to specification prior to shipment If recalibration is needed refer to the following procedure The following equipment is used to calibrate the 9220 Input Card 1 Digital Voltmeter Multimeter DVM 4 digit resolution or better COPYRIGHT 9 87 LSCI Model DRC 91C 93C 2 Precision Standard Resistor 1 k
95. 9220 9220 3 9220 Input Card 9220 8 REPLACEABLE PARTS Included in this section is Figure 3220 1 It includes the Model 9220 input schematics replaceable parts list and illustrated component layout Refer to the manual for ordering information 2220 4 Model DRC 91C 93C COPYRIGHT 9 87 LSCI REPLACEABLE PARTS LIST 9220 ANALOG INPUT CARD Part ITEM LSCI NO Number 101 034 101 025 106 142 102 072 105 649 102 074 104 005 102 043 104 001 104 355 104 356 104 099 104 461 104 460 102 020 104 051 104 078 diy _ Description CAP PP 1 0MF 100V 100V _ CONNECTOR IC TO BP 6 POST LOCKING HEADER TRANSISTOR PNP SIGNAL SWITCH 2 POS 4 POLE INTERLOCKING MOSFET P CHANNEL IC OP AMP VOLTAGE REFERENCE 6 95V IC OP AMP IC OPTOCOUPLER Ic OPTOCOUPLER IC P S SHIFT REGISTER IC A D CONVERTER IC A D REFERENCE REGULATOR 5V TIMER IC SWITCHED CAPACITOR MPP2X 1 0 100 10 MPP 11 33MFD 2420 09 75 1061 283906 2 7 5 4UGRP 3N163 LM308 LM399H 276016000 74016010 CD4021BCN 1CL7104 16CPL ICL8068ACPD 79105 7555 LTC1043 lt 1 32 GND DF GND 5 GND Ald 1 NASA IN BUF IN 101 034 101 025 106 142 102 072 105 649 102 074 104 005 102 043 104 001 104 355 104 356 104 099
96. 9317C and 100 000 ohms with 1 ohm resolution for the 9318C To read temperature accurately a calibrated sensor and an 8000 Series Precision Option is quired Refer to Section 9317C 9318C 5 for a detailed description of the operation of the 9317 9318 9317C 9318C 3 SPECIFICATIONS Specifications for the Model 9317C 9318C Resistance Input Card are given in Table 9317C 9318C 1 of this Section COPYRIGHT 12 87 LSCI 9317C 9318C 4 INSTALLATION The 9317C 9318C can be installed in a DRC 91C or a DRC 93C as either Input A or Input B or both with two cards The 9317 9318 is installed prior to shipment if ordered with either controller If only one 9317C 9318C is ordered and its input is not specified when ordered it is installed in Input Use the following procedure for the installation of the 9317 9318 Resistance Input Card Note when card is ordered for field installation the Input Card Configuration Table located on the first page of the Instruction Manual should be updated to keep documentation current WARNING To prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment before removing cover 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off Note from the calibration cover the position of the Input Card the 9317C 9318C will occupy 2 Remove th
97. Before it is decided that U47 and U48 are bad be sure the relays K4 K8 are working If they can be heard clicking as they are turned off and on then they are probably operating properly They are turned off and on by se lecting different heater ranges Model DRC 91c COPYRIGHT 3 88 LSCI Table 5 1 Input Card Characteristics Sensor Type Pange DD Test Display Standard ith st Input S Resistor in Curves d Units Lodi Resolution Units Curves K E E 8210 1 4 to 475K 9210 3 0 2 9999 9220 3 9210 6 GaAlAs 4 to 325K 0 1mV 0 2mV reg 1 0000V no std crv 9220 6 Diodes 0 6 5535V see note 3 ur s o d d Fe ML M M edo b ll E 8219 1 RhFe 14 to 800K 9220 R1 RTDs 0 99 9990 prend e ceu el occ 9999 I note 5 4 0 3 to 100 see note 1 no std crv see note 3 1 4 to S 25K 10 0000 1 4 to 100K 0 05 fr no std crv see note 1 note 3 0 25 fr TOk 100k Note 1 Pi ae a erature limit is dependent upon e 195156 characteristic of sensor used Note 2 0 1 to Sensor voltage pinned at 9317C or Tomy 9318C Note 3 To read in temperature these input cards must be use with calibrated sensors and the 8001 precision option Note 4 9317C and 9318C will read to 1 ohm full scale with reduced accuracy COPYRIGHT 3 88 5 9 SLOT 6 SLOT 5 C12 C17
98. C 91C input button for longer than one Second This operation differs if a scanner is present If the A button is pressed the input increments also for both the A and B buttons the resolution as well as the dwell time is displayed 3 8 5 DISPLAY AND DISPLAY SENSOR Units 3 8 5 1 Units Select The display units are indicated by LEDs in the block directly below the DISPLAY SENSOR block The units of the display are changed by simultaneously depressing the yirs button with the double UP ARROW or double DOWN ARROW vv until the units desired are obtained Each time the 44 key is pressed the units cycle clockwise and each time the vv key is pressed the units cycle counterclockwise The units which do not pertain to the input card selected are automatically skipped i e only one of the sensor units V 0 nF is possible depending on which sensor input card is present within the instrument For any input card except the 9215 the DRC 93C will read temperature regardless of whether a curve is stored within the instrument which corresponds to the temperature sensor being interrogated For diodes germanium carbon glass and all other negative temperature dependence sensors the default curve is Curve 00 which is the D curve for the DT 500 DRC sensors For a positive temperature depen dence temperature sensor such as platinum and rhodium iron the default curve is Curve 03 which is the standard 3750 DIN curve for
99. C 91C provided that Bit 6 in the Status Register Mask is set See Section 4 11 3 With the SRQ bit of the Status Register mask disabled SRQ interrupt by the DRC 91C will be generated however the BUS CON TROLLER can still read the Status Register to determine appropriate instrument conditions 4 18 Model DRC 91C 4 11 2 The Status Register and Status Reports The DRC 91C Status Register is a single byte of data from the DRC 91C containing five bits called the Status Reports which give information indicating which process is complete whether the channel was changed or a limit overload or error countered The Status Register can be read at any time by means of a Serial Poll Enable command Reading the Status Register resets the Status Register to all zeros so that only new status reports will be registered by the DRC 91C Execut ing the Q command Section 4 11 3 also resets the Status Register to all zeros Reading the Status Register resets all of its bits to zero 4 11 2 1 Status Reports O and 1 Display and Control Data Ready Bit O of the Status Register is set when a valid Display data reading is available Bit 1 of the Status Register is set when a valid Control data reading is available If the Service Request is enabled either one of these being set will cause the DRC 91C to pull the SRQ manage ment low to signal the BUS CON TROLLER These bit s are reset to zero upon reading the St
100. CAP TANT 10MF 35 CAP CER 30PF 500v CAP PP 33MF 100V CAL ENABLE 4 DIP RA IC MICROPROCESSOR IC EEPROM OPTOCOUPLER IC D A CONVERTER IC ANALOG SVITCH IC SWITCHED CAPACITOR CONVERTER IC BINARY COUNTER REGULATOR 5 IC EPROM CRYSTAL 5 000MHZ CONNECTOR 6 POST RA HDR 9317C RESISTANCE SENSOR INPUT CARD 1190106 0035084 CD15bED300J03 11 T6PSBO4 MBOCS1VS x2404 2731 _ 5 LF13202 LTC1043 TSC500CPE CD4020BCN 79105 27 64 3 1 5 000 2 XU13 XU T U P1 EE XU14 REPLACEABLE PARTS LIST 9318C RESISTANCE SENSOR INPUT CARD 21190106 0035 1 Description 101 137 137 CAP TANT 10MF 35V 101 067 101 025 105 405 104 509 104 652 104 001 104 345 104 419 104 060 104 078 104 465 104 089 104 098 104 020 104 660 103 990 106 142 500 CAP PP 33MF 100V CAL ENABLE 4 DIP IC MICROPROCESSOR IC EEPROM IC OPTOCOUPLER 1C D A CONVERTER IC ANALOG SWITCH IC SWITCHED CAPACITOR IC A D CONVERTER IC BINARY COUNTER REGULATOR 5V _ IC EPROM CRYSTAL 5 000MHZ CONNECTOR 6 POST RA HDR 76 5 04 X2404 5 00403 __ 11
101. CU DT 470 DI DT 470 CY between the adapter and mounting surface The CU adapter has four color coded leads Red Green V Clear V and Blue CY adapter has two color coded leads Yellow and Green The green lead on the adapter is the cathode Application Notes 11 Lake Shore Cryotronics Inc DT 470 ET DT 470 MT SD 6 32 sensor Threaded Stud Sensor Cathode an es Anode 5 lt gum DD 5 5 mm 5 5 iS across 6 mm across flats 6 mm flats Cathode DT 470 ET 3mm x0 5 metric thread y FE DT 470 MT Both adapters are gold plated copper hex head bolts with the SD package mounted in a slot on the adapter head The ET adapter screws into a 1 4 inch deep 6 32 threaded hole while the MT adapter screws into mm deep 3x0 5 mm threaded hole Before assembly the threads should be lightly greased with Apiezon N Grease Do not over tighten since the threads are copper and can be easily sheared Finger tight should be sufficient DT 470 BO The BO adapter should be mounted in the same manner as the CU The BO adapter contains its own thermal anchor and is an epoxy free assembly DT 470 CO The CO adapter is a spring loaded clamp to attach the DT 470 SD package to a flat surface It maintains pressure on the SD package as the temperature varies First remove the hold down cap which holds the three piece CO assembly
102. EE address of 12 the display would indicate Add12 This address can obviously be changed by the user and verification of that change always given power up Note that this ad dress is only read by the in Strument on power up 3 The unit then displays for INPUT A the curve number as sociated with that input on the upper display and on the lower display the input option card and its configuration 4 The unit then displays the same information for Input B 5 unit then goes into normal operation 3 7 2 POWER UP STATUS A provision has been made to store parameter changes in the DRC 91C memory NOVRAM The A and B units the control units heater range and set point as well as the scan dwell times can be stored as power up settings When enabled any time the parameter is changed either in the LOCAL or REMOTE mode the NOVRAM is updated The inter nal DIP switch setting main board S7 switch 2 controls whether or not the settings are updated The updating is disabled switch 2 off at the factory prior to shipment 3 8 DISPLAY SENSOR Block 3 8 1 DISPLAY SENSOR Input Ihe choice of DISPLAY SENSOR input as well as enabling the 11 scan function is made with keys located in the DISPLAY SENSOR Block The selection of A or B input and SCAN is indicated by the LEDs to the 3 4 Model DRC 91C left of these keys When the 8229 Scanner Conversion Option is not present the display can be toggled
103. ING INSTRUCTIONS The following discussion references the DRC 91C at address 12 The allowable address codes are given in Table 4 2 Therefore its Talk ASCII Code is IL and its LISTENER ASCII Code is comma The controller referred to the following discussion is the BUS CONTROLLER and is normally a digital computer It should not be confused with the temperature controller on the bus DRC 91C Set the IEEE Address of the DRC 91C to 12 by Section IV making Switches 5 and 6 CLOSED 1 4 7 and 8 OPEN 0 and make sure Switch 1 is OPEN 0 to select CR LF as the terminating charac ters Note that this should be done prior to turning on the instru ment since the DRC 91C updates the IEEE address power up only Confirm that the address selected is correct by holding in the REMOTE button for longer than one second and observe the IEEE address on the front panel display as follows 91C Add12 DRC 91C Command Summary of Instrument Setup Summary of Input Command Formats Choices of the commands are Table Interface Setup Commands Changes terminating Characters Select the A or B Input Resolution 4 6 Selects EOI status Selects Remote Interface Mode Clear Command Table Instrument Setup Commands 4 7 FOC4 Select Control Units FlAC F1BC4 Select or B Input Units F2C4N4 Select Display Sensor F3AN4 F3BN4 Table Control Setup Commands 4 9 S etc Set Point Input 4 10 PN4N5 etc Proportional
104. INTRODUCTION 152 DESCRIPTION 1 3 SERCIPICATIONS gt Me 1 4 OPTIONS SECTION II INSTALLATION INTRODUCTION 4 6 eX amp INITIAL INSPECTION r a gt s e s e e as s PREPARATION FOR USE s e 2 3 1 Power Requirements Power Cord Grounding Requirements Wt Bench USG e a w Rack Mounting Sensor Input Connections J3 Sensor Output MONITORS SENSOR ID Switches Heater Power 2 3 9 1 HEATER POWER Limit e 919 9 UJ LJ Wo ya i Lut REMOTE SENSOR ID Connector gt IEEE 488 INTERFACE Connector gt OPTIONS X ous 5 44 2 6 1 Ihe RS 232C Option 2 The 8229 Scanner Option 3 Ihe 8225 Linear Analog Option 4 High Resolution Set Point 5 6 2 Un gt The 8001 and 8002 Precision Options 2 7 ENVIRONMENTAL REQUIREMENTS 2 7 1 Operating Temperature 2 7 2 Humidity Altitude 2 8 REPACKAGING FOR SHIPMENT SECTION III OPERATING INSTRUCTIONS 3 1 INTRODUCTION UE 3 2 INSTRUMENT CONFIGURATION Ek dew 3 2 1
105. ION COMPATIBILITY The special nature of thermocouple sensors and their connections limits compatibility with Lake Shore options and accessories Thermocouples must be attached directly to a terminal block The 8229 Scanner Input Option and 8085 External Sensor Scanner are not adapted with terminal blocks so they can not be used with the 9305 Thermocouple Card The 8225 Linerized Analog Output Option will function in temperature units only COPYRIGHT 6 88 LSCI Model DRC 91C 93C with a 9305 installed giving an output of 10mV K The 8000 series Precision Calibration Options are not available from Lake Shore for thermocouple sensors 9305 11 REPLACEABLE PARTS Included in this section is Figure 9305 1 showing the Model 9305 Thermocouple Input Card Schematic Replaceable Parts List and illustrated Component Layout Also included is Figure 9305 2 showing the 9305 Terminal Block Schematic Replaceable Parts List and Component Layout COPYRIGHT 6 88 LSCI 9305 Thermocouple Input Card 9305 11 9305 Thermocouple Input Card Model DRC 91C 93C Table 9305 4 9305 Thermocouple Curves 15 0000 15 0000 J a orm Wh 2395712 4 6676 4 6067 4 5259 4 4571 4 3703 4 2869 3 9928 3 8830 3 8126 3 7411 3 5948 3 4436 3 2026 3 0374 2 8689 2 6957 2 5184 2 2468 2 0615 1 8725 1 5839 1 2905 0 9912 0 6847 0 1670 0 0378 0 2387 0 6350 1 0387 15 0010 4 5 2982 5 2815 5 2594 5 2285
106. NABLE to the program above enables the HP to receive and transmit handshake mode Example 3 General Serial Interface Interconnection The HP 86B Serial Interface Standard cable configuration already takes care of some of the interface interconnection problems to route signals to their proper pins Figures 8223 5 and 8223 6 give more general interconnection configurations for Half Duplex with and without Handshake Figure 8223 5 General Serial Interface Interconnection for Half Duplex with Handshake Protective Ground Transmitted Data Received Data Request to Send Clear to Send Protective Ground Transmitted Data Received Data Request to Received Line Signal Detector Data Terminal Ready Data Set Ready Signal Ground Received Detector Data Terminal Ready Data Set Ready Signal Ground COPYRIGHT 12 87 LSCI Transmitted Model 8223 RS 232C Interface Figure 8223 6 General Serial Interface Interconnection for Half Duplex without Handshake Protective Ground Protective Ground Transmitted Data Received Data Signal Ground Data Received Data Signal Ground Note It may be necessary to jumper pins 5 6 8 and 20 to disable the handshake functions of the Host This is not required for the 8223 Interface 8223 8 REPLACEABLE PARTS Included in this section is Figure 8223 1 It includes the Model 8223 RS 232C Interface Option Schematic replaceable parts li
107. NPUT Connections for 21 INPUT A ana J2 Sensor Connections e s J3 MONITORS Connections gt Rack Configuration INPUT 02 SENSOR ID Definitions Ede ut wid SENSOR ID Standard Curve Address REMOTE SENSOR ID Connector Assignments va SECTION III OPERATING INSTRUCTIONS Figure Table Table Table Table Figure Figure Table SECTION IV Table Figure Table Table Table Table Table Table Table Table Table Table Table Figure Table Table Table Table Table Table 3 1 2 12 3 2 272 3 4 3 3 2 2 3 2 4 1 4 1 4 2 4 3 4 4 425 4 6 4 7 4 8 4 9 4 10 4 11 4 13 4 2 4 14 4 15 4 16 4 17 4 18 4 19 12 87 DRC 91C Temperature Controller Front Panel SYSTEM RESOLUTION VERSUS SENSOR SENSITIVITY Standard Curve Information e Sensor Curve Table Information Precision Option Table Position versus Curve Correlation Table SENSOR ID Switch 4 1 Reset and Rate Ties for 91C amp xo DRC 91C Temperature Controller Rear Panel Pin Assignments for the J5 REMOTE SENSOR ID Connector REMOTE OPERATION Interface Functions s IEEE 488 Address Switch for the DRC 91C E Xe cd Allowable Address Codes for the DRC 91C IEEE 488 Bus Commands
108. POST CNNCTR CONNECTOR TERMINALS INPUT TRANSFORMER TX2 TO MB 4 POST RCPTCL CONNECTOR TERMINALS OUTPUT TRANSFORMER FAN ASSEMBLY MFR PART NO _ 113 131 126 127 126 195 609 1630 609 1631SP 107 017 MDL 1 MDL 1 2 105 671 105 676 KNSSO1BA 105 677 FN372 6 22 2139 09 50 3061 2878 08 50 0116 126 218 126 198 111 0113 001 111 0103 001 111 0103 001 LSCI 765 7301 M Y 2 Q IRF9130 M8080 1G40 2139 09 50 3091 2878 08 50 0116 C696 114 2139 09 50 1041 2878 08 50 0116 696 115 107 180 Fi SHAFFNER FN372 6 22 TO DISPLAY BOARD MOUNTED ON TOP TES MOMENTE RIGHT SIDERAIL pee oM Ui o o Txi n Dp RED D m P ORN WHT JA1 7 45 MICROPROCESSOR O TP14 CARD BLK 5 MAIN BOARD C3 B 68 F o TP12 J 1 3 1 4 15 D C 5 15 D TP9 JAe 1 4 8 gt Tid GRN 15 A GRN WHT JA2 2 vt v O 15 B m YEL 8 10 5 1A YEL S1 SHOWN IN OFF AM DIGITAL GND POSIT ITION GRY WHT JA2 4 A f Q v E 0 o ANALOG CND BLU 7 NA V _ CHANNEL A CURRENT SOURCE SUPPLY BLU Q av cs a V VIO 5 TL
109. POT DVD B DVD A POT CLK B DATA IN GND D A DATA IN GND D GND D SP WR B CLK A CLK RESET V SP ZERO ADJ CS PDAT 5 D 6 6 D RATE V _INT KB SLOT SLOT 3 SLOT 1 MICROPROCESSOR AND OPTION 3 OPTION 1 MEMORY CARD OPT3 ID _OPTI ID INT OPT _ INT OPT1 INT OPT1 DBIN RESET _ DBIN RD WR RD RD RI IEEE CLK RESET PID DATA ALE INTS A2 Ai 2 2 A2 Ag AD ADS 8 CLK OPT3 ID ADS vice ee _A CLK AD4 5 POT CLK ADe PID CLK1 PID CLKe ADB B DATA IN A DATA INO 45 D mw CS OLD CARD 5 D __ C 4 __ CS 6 CS DISP CS 0PT3 GND D 5 2 CS OPT1 CS 0PT1 15 5 15 D 5 0 DRC 91C MAINBOARD INTERCONNECTIONS y 6 5 4 I ELM 4 e 7 e 5 5 888888 5 o _ IN DATA 72 CONT ID e d e E NOTE 1 U32 PIN 4 PIN 11 SHORE CRYOTRONICS INC DRC 91C MAINBOARD SETPOINT AND SUMMATION T es 14 81 s rptu a B 445 86 81 ou aTe m tat 11 ER SHEET 5 OF 7 F igure Schematic 31 gt Board 5 Setpoint and ration 6 0 4 35 ree e 1
110. R serial poll cap ability Talk only Unaddressed to Talk if addressed to Listen Basic LISTENER Unaddressed to Listen if addressed to Talk Service Request capability Complete Remote Local capablty No Parallel Poll capability Full Device Clear capability No Device Trigger capability No System Controller capablty Open Collector Electronics COPYRIGHT 3 88 LSCI Model DRC 91C 4 4 DRC 91C IEEE 488 ADDRESS SWITCH The IEEE 488 Address Switch is located on the instrument s rear panel see Figure 3 2 Key No 9 Refer to Figure 4 1 for the following discussion 4 4 1 Terminating Characters delimiters Switch 1 is used to define the instrument s terminating characters delimiters The OPEN 0 position selects the ASCII characters CR and LF Carriage Return and Line Feed as the terminating characters for input and output data For the output data from the DRC 91C back to the computer over the Bus the EOI line is set by the DRC 91C with the output of the Line Feed LF This setting 0 for switch 1 is the Section IV When Switch 1 is CLOSED 1 a variable terminating character format may be selected for the input and output data this configuration the power up default terminating characters are LF and CR with the EOI line being set with the output of the Carriage Return CR How ever the two terminating characters can be changed via input data to the DRC 91C as detailed in Table 4 6 If the terminati
111. REED RELAY 20 W DRY REED RELAY 50 W B1A5AH P1A5A 4 T A A 102 072 TRANSISTOR PNP 2N3906 113 063 no RES PREC 100K MATCHED PAIR 01 103 399 1 RES MTF 30 1 1 4W 1 103 495 1 9 84 1 4W 1 103 540 1 RES MTF 2 92 1 4W 1 103 586 1 RES MTF 3 5 1 W 1 103 583 1 RES MTF 1 25 3 W 1 103 675 1 RES WWD 587 5 W 1 105 014 POWER SWITCH 2 POLE F 01 2UEE NE15 1B 105 408 106 229 106 227 765808 1 80 51 DIP SWITCH 8 POS CONNECTOR 25 50 CONNECTOR 18 56 102 011 102 021 102 014 REGULATOR 5V REGULATOR 5V REGULATOR 15V MC7805ACT 7905CT 7815CT 102 024 REGULATOR 15V 7915CT gt UN gt 2 A e OX Ul 102 012 REGULATOR 8V 7808CT 102 022 REGULATOR 8V 7908CT 102 036 REGULATOR ADJ 1 2 57V LM317HVK STEEL 104 712 IC IEEE CHIP TMS9914ANL 104 710 IC IEEE SUPPORT CHIP SN75160AN 104 711 IC IEEE SUPPORT CHIP SN75161AN 104 529 IC PORT EXPANDER 82C554A 5 104 310 IC 8 BIT MULTIPLEXER 811595 104 419 IC 16 BIT D A CONVERTER DAC7038H 5 104 061 IC DISPLAY DRIVER MM5480N 104 408 1 10 BIT D A CONVERTER AD7533JN 104 076 IC DUAL SPDT ANL SWITCH HI5043 5 104 088 IC QUAD
112. SOR ID is closed 1 the Reference Junction 9305 6 Model DRC 91C 93C Compensated value of the thermocouple voltage is displayed When Switch 3 of the SENSOR ID is open 0 the actual measured thermocouple voltage uncompensated temperature is displayed With the 9305 selected as the Display Sensor hold the LOCAL key to show card type and curve number If compensation is active the display will show 9305 and if it is inactive 9305 Table 9305 3 Curve Numbers Thermocouple Standard Type Curve Chromel vs Chromel vs Au 0 03 at Fe 9305 7 3 Selection of Reference Junction Compensation the DRC 93C When 9305 Thermocouple Input Cards is installed pressing the SENSOR key will display either 9305 or 9305 The 9305 means that the thermocouple voltage is corrected for the Terminal Block temperature The 9305 means that the thermocouple voltage is being displayed with no compensation To select whether Reference Junction Compensation is used or not is accomplished from the front panel by a combination of the SENSOR key SCAN key and the key and key The procedure is as follows COPYRIGHT 6 88 LSCI Model DRC 91C 93C 1 Press and hold the SENSOR key 2 While holding the SENSOR key press the SCAN key You may now release the SENSOR key 3 To change the sign if in the upper Display press the key while still holding down the SCAN key Similarly to change the sign
113. Scan Information Display Scan Information Space a Line Set for WI Ask Input Cards and Options Display string WI dum Gum d bau 4 d gt m u Qum Qum Dm 05 m 4 26 COPYRIGHT 3 88 LSCI Model DRC 91C 4 14 SENSOR CURVE PROGRAMMING INSTRUCTIONS The commands which will either output input edit or erase Sensor Curve are given in Table 4 16 In addition the commands to assign or change assignments of the various curves to the Sensor ID tables both A and B are given in Table 4 16 4 14 1 The XDT Command This command from the BUS CON TROLLER tells the DRC 91C that when it is asked to output data that data should be the output of the standard Sensor Curves stored Precision Option Curves stored and the format associated with the REMOTE SENSOR ID Remote Position to Sensor Curve assignments as given in Table 4 17 This output is defined as the Sensor Curve Infor mation Table SCIT As can be seen from the output shown on this page the instrument is shipped with all remote positions calling up Standard Curve 02 The information lines for Sensor Curves 05 through 31 will only be present if these curves are actually present either as user generated curves Precision Option curves The Information Table is output as one very long charac
114. T 2 88 LSCI field Capacitance Input Card Configura tions are given in Table 9215 1 Table 9215 1 Specifications of the Capacitance Input Card Display Resolution 5 digits Display Units Capacitance in nanofarads Temperature Accuracy A function of sensor sensitiv ity See Table 9215 2 Unit supports capacitance only Sign of Temperature Coefficient User Seiectable by Switch on on DRC 91C Keys on DRC 93C or via Computer Interface Magnetic Field Sensitivity lt 0 15 for lt 19 Tesla and gt 4 2K See Section 9215 3 9215 15 Sensor Excitation 5 kilohertz charging current Capacitance Range 0 to 15 nF 0 30 nF with reduced accuracy Sensor ordered separately CS 401 Series from LSCI or or other Capacitance Sensor Resolution 0 001 nF Accuracy 0 25 of Full Scale Range 0 000 to 29 999 nF Analog Output Signal 0 1 times capacitance nF in volts 9215 150 Sensor Excitation 1 kilohertz charging current Capacitance Range 0 to 150 nF Sensor ordered separately CS 501 Series from LSCI or other Capacitance Sensor Resolution 0 01 nF Accuracy 0 25 of Full Scale Range 0 00 to 149 99 nF Analog Output Signal 0 02 times capacitance nF in volts 9215 1 9215 Capacitance Input Card DRC 91C 93C Table 9215 2 Typical Temperature Ranges and Sensitivities 8 401 1 1 7609 2 0347 1184 2 4227 2 3544 1 4847 0 9445 0 6307 CS 401GR Bl
115. This channel will be read over the IEEE 488 Bus only if the channel is designated as the Display Sensor or Control Sensor Normal operation would be for the B input to be Control Sensor input with the Display assigned to the A channel selected by this command directing the appropriate sensor from the scanner input to the A input card 4 10 4 Enabling the Scan Function YS Command Upon sending the YS command from the BUS CONTROLLER the DRC 93C starts its scan of the inputs from the channel input which it is currently on The scan sequence is AO Al A2 A3 A4 B AO etc with any channel whose dwell time is set to zero being skipped It is strongly recommended that the control channel be the B channel when the scanner is used If it is not it will be changed if a scanner COPYRIGHT 3 88 LSCI Model DRC 91C YAN4N5N4 or YBONSN4 After YH cmmd Select Scanner Channel AC AO thru 4 Command are YCAO YCA1 YCA2 YCA3 and YCA4 asynchronously selects a scanner channel for readout Enable the S CAN function Disable or H old the SCAN Section IV DRC 91C Command Request Summary for Scanner Functional Description Set the AN 0 4 or BO Scanner channel dwell time time to seconds are 000 thru YAO99 YA100 thru YA199 etc is 00 to 99 seconds Forms Forms of the Command Scan Information 1 2 3 4 5 6 7 8 10 11
116. USER S MANUAL Model DRC 91C Temperature Controller 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 akeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA Internet Addresses sales lakeshore com service Q 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 nght 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 Manual No MAN DRC 91C December 1987 SERIAL NUMBER SOFTWARE
117. VERTER O C 7406 U9 10 104 160 TRANSISTOR DRIVER UDN 2585A U11 104 261 3 8 LINE DECODER 7015138 4 mE CABLE DB TO MB 2 CABLE DB TO 012 Figure 91 2 Component Layout DRC 91C Display Board 100 lel gt gt Slee AD3 198 Ab4 pat ADG kb7 ALE JNT KB MEE um IP PEEL ux 18 M9 8 uc CS DISP 1 U7 U8 7406 14 5 0 PIN GND D pRC 91C DISPLAY BOARD DIGITAL SECTION M g 448 06 82 TUE 29 14 97 a mom s9 jm 52 Ae A 8 jus w a LOCAL DISPLAY 1537 5082 7611 0514 0516 5882 7611 5882 7611 m d p 2513 E 5 7 1 8292 761 1 256 20517 e IELE 5082 7616 Us emen ac 2 662 1611 6862 7611 REARS 6882 7611 LAKE SHORE CRYOTRONICS INC DRC 91C DISPLAY BOARD DISPLAY SECTION 09 14 87 Figure 91C 2c Schematic DRC 91C Display Board LAN 74 86 010 TP 8 2 1 14 15
118. age is 2 we 1 AV V V la 1n 1 lac e 2 where lac X lac Is If a small signal linear model is used the rms voltage across the diode can be easily related to lac lee OV hs Vine E 5 5 Evaluation of Eq 5 and substitution back into 4 yields 2 i e 6 I lgc 5 1 nkT where 2 eVims lt 1 for a physical solution Equation 6 predicts an offset voltage which is independent of both frequency and dc operating current and is shown plotted in Fig 4 by the solid line The agreement with the experimental measurements is quite good verifying the overall picture as to the effect of induced currents on diode temperature sensors The results recorded at 305 K are described equally well by Eq 6 16 1uA 10 uA 100 uA 0 1 2 3 4 5 6 7 8 RMS AC VOLTAGE mV FIGURE 4 DC offset voltage as a function of rms ac voltage across a silicon diode temperature sensor operating at 77 K The symbols represent data recorded at three different dc operating currents with a 60 Hz signal superimposed The solid curve gives small signal model results while the dashed curve represents the extended calculations Equivalent temperature errors are indicated along the right edge 01 K 001 K 1uA 10 uA 100 uA 0 4 8 12 16 20 24 28 32 RMS AC VOLTAGE mV FIGURE 5 DC offset voltage as a function of rms ac voltage across a s
119. ally indicated the color black Metric threaded cable lockscrews also black must be used to secure an IEEE 488 interface cable to the instrument Model 8072 488 Interconnect Cables one meter long available from Shore 2 5 Section II 2 6 OPTIONS 2 6 1 The 8223 RS 232C Interface The RS 232C option is described in Section VI of this manual including connections 2 6 2 The 8225 Linear Analog output is described in Section VI of this manual 2 6 3 The 8229 Scanner Input Option is described in Section III and Section VI of this manual 2 6 4 The High Resolution Set Point expands the set point resolution to 0 01 kelvin above 100K and 0 001 kelvin below 100K The equivalent voltage is expanded to 25 micro volts out of 3 volts full scale This results in setability of approximately 0 01 kelvin above 40K and 0 001 kelvin below 28K for the DT 470 series sensors 2 6 5 8001 Precision Option Cus tom programming of specific Sensor calibration curve s at factory Provides highest degree of readout accuracy 2 6 6 The W50 and W60 Output Op tions will deliver 50 or 60 watts respectively The W50 is rated at 1 ampere and 50 volts into a 50 ohm load with the W60 rated at 1 5 amperes at approximately 43 volts into a 25 ohm load These are factory options only 2 7 ENVIRONMENTAL REQUIREMENTS WARNING To prevent electrical fire or shock hazards do not expose the instrument to rain
120. alter the time response of the measurement system so allow sufficient time for the capacitor to charge and for the system to equilibrate If the dc voltage reading across the diode increases with the addition of the capacitor there are probably ac noise currents present The second method simply involves measuring the ac voltage signal across the diode Although an oscilloscope is often the logical choice for looking at ac signals many do not have the sensitivity required and they often introduce unwanted grounds into the system and compound the problem Most testing can be performed with the same digital voltmeter used to measure the dc voltage by simply selecting the ac voltage function There should be no ac voltage across the diode If there is the data presented in the following sections can be used to estimate the potential error in the temperature measurement ll EXPERIMENTAL In order to quantify the effects of induced currents on silicon diode temperature sensors the circuit of Fig 3 was used to superimpose an ac current on the dc operating current The dc current source was 10 battery powered with currents selectable from lt 1 uA to gt 1 mA The signal generator could be varied in both amplitude and frequency All voltage measurements were made with a Hewlett Packard 3456A d HE voltmeter in either the dc voltage mode or the ac rms voltage mode The dc measurements were taken with an integration time of 10 DVM
121. amount of error signal allowed before the controller is directed to produce full output power The DRC 82C requires a 0 to 8 volt signal from the deviation amplifier to drive the power output stage from zero to maximum In Figure 2 For Av 1000 there is a narrow band of error signals 0 to 8 mV within which the proportional action occurs This proportional band expands tenfold for A 100 and so on for lower gains obviously gain and proportional band are inversely related Proportional band is expressed as a percentage of full scale range Note that the proportional band in mV can be converted to temperature in kelvins if the sensitivity of the sensor in mV K is known As an example suppose the sensor Variable Set Point Deviation Power Stage Amplifier Non Inverting Inverting FIGURE 1 Block diagram of Cryogenic Temperature Controller A is amplifier voltage gain Proportional Proportional 100 Band 1000 8V Deviation A 1000 Amplifier Output Error Signal FIGURE 2 Output plot of the deviation amplifier showing Proportional Bands for gain settings of 100 and 1000 For the DRC 82C the maximum available gain is 1000 8 E 5 E REN 5 2 Error 2 Signal 40 mV 0 B 0 8 K 0 K 16 K 0 FIGURE 3 Output Power versus error signal in voltage or equivalent temperature of sensor for two different power settings A corresponds to a se
122. ands and Requests 4 8 4 7 INSTRUMENT SETUP COMMANDS AND REQUESTS dog et ae ay 4 8 4 7 1 EOI Status The ZN 4 8 4 7 2 Interface Mode The MN Command s s e s e s s 4 8 4 7 2 1 Local uM 4 8 4 7 2 2 Remote 4 10 4 7 2 3 Local Lockout 4 10 4 7 3 Terminating Characters The TN Command 4 10 4 7 4 Clear WO xe we XP 4 10 4 7 5 The Data String 20 4 10 4 7 6 The WI Data String b 4 10 4 8 SELECTION OF SET POINT UNITS INPUT UNITS DISPLAY SENSOR RESOLUTION Table 4 27 4 10 4 8 1 Units for Set Point The FOC Command 4 10 4 8 2 Units for and B Inputs The and F1BC Commands r 4 11 4 8 3 Display Sensor Selection The F2C4N4 Command 4 11 4 8 4 Resolution for Inputs The F3AN and F3BN Commands s s s e 4 11 4 8 5 The and B SENSOR ID Information The BC C5 Commands 4 11 4 8 6 Sensor ID on Return to local 4 11 4 8 7 The W1 Data AES OG A DES 4 13 4 9 THE CONTROL COMMANDS 4 13 4 9 1 The Set Point Value x The S Command Ee 4 9 2 The WP Request Data String EX 4 14 4 9 3 Setting the GAIN Proportional The P Command 4 15 4 9 4 Se
123. aracter before the next one becomes available The overrun character s are lost Framing Error may be caused by signal line transients or incorrectly specified stop bits or or character length Input Buffer Overrun caused by more than 256 characters being input input to the FIFO buffer Any characters received after the 256th character are lost 8223 7 INTERFACING EXAMPLES Example 1 HP 86B Computer Half Duplex Without Handshake 8223 5 Model 8223 RS 232C Interface HP82939A Serial Interface for the HP 86B is preset at the factory for the following default values 1 Interface select code 10 2 Baud rate 300 Baud 3 Autohandshake Off 4 Character Length 7 bits Model DRC 91C 93C output it to the 8223 will then input the 8223 s response display return for another command The program specified it and 10 REM HALF DUPLEX W O HANDSHAKE 15 REM I O TEST RS232 TEST1 20 DIM A 256 B 3000 25 REM AS IS OUTPUT BS IS INPUT 30 INPUT AS MAKE SURE TO GIVE AN 35 OUTPUT STATEMENT COMMAND 40 OUTPUT 10 AS OUTPUT COMMAND 5 Parity Odd 50 ENTER 10 BS INPUT THE DATA 55 1 FROM THE CONTROLLER 6 Stop bits 1 60 DISP BS DISPLAY DATA 70 GOTO 30 RETURN FOR MORE 7 Cable Option Standard 25 pin 80 END Socket Example 2 HP 86B Computer Half Since the HP default Baud rate character length parity and stop bit configuration are the same as those of the
124. ases tnis means that service is required Transfer of the information on the data lines is accomplished through the use of the three signal lines DAV Data Valid NRFD Not Ready for Data and NDAC Not Data Ac cepted Signals on these lines operate interlocking hand 4 2 Mnemonic Interface Function Name 2 Model 91 shake mode The two signal lines NRFD and NDAC are each connected in a logical AND to all devices connected to the bus The DAV line is pulled low by the TALKER after it places its data on the DATA lines This tells the LISTENERS that information on the DATA lines is valid A LISTENER holds the NRFD line low to indicate it is not ready Since these lines are connected in a logical AND to all other devices then the NRFD line will not go high until all of the devices are ready The NDAC line is pulled low by a LISTENER while it is receiving the DATA and lets it go high when the DATA is captured Since the NDAC lines of all devices are connected in a logical AND the NDAC line will not go high until all devices have received the DATA 4 3 INTERFACE CAPABILITIES The IEEE 488 Interface capabilities of the Model DRC 91C are listed in Table 4 1 as well as in mnemonic format on the instrument s rear panel Table 4 1 Interface Functions Source Handshake Capability Acceptor Handshake Capability Basic TALKE
125. at is measured and the true sample temperature Such temperature errors can be eliminated by proper selection and installation of the connecting leads In order to minimize any heat flow through the leads the leads should be of small diameter and low thermal conductivity Phosphor bronze or manganin wire is commonly used in sizes 32 or 36 AWG These wires have a fairly poor thermal conductivity yet the resistivities are not so large as to create any problems in four wire measurements Lead wires should also be thermally anchored at several temperatures between room temperature and cryogenic temperatures to guarantee that heat is not being conducted through the leads to the sensor A final thermal anchor at the sample itself is a good practice to assure thermal equilibrium between the sample and temperature sensor Note that the CU CY BO and DI mounting adapters serve as their own sample thermal anchor If the connecting leads have only a thin insulation such as Formvar or other varnish type coating a simple thermal anchor cn be made by winding the wires around a copper post or other thermal mass and bonding them in place with a thin layer of GE 7031 varnish There are a variety of other ways in which thermal anchors can be fabricated and a number of guidelines which may be found in detail in the references given below SENSOR MOUNTING General Comments Before installing the DT 470 sensor identify which lead is the anode and which lead is the ca
126. at the Temperature Coefficient is nega tive Select the Temperature Coefficient sign from the front panel by using a combination of the SENSOR key SCAN tl key and the 44 key and vv key as follows 1 Press and hold the SENSOR key 2 While holding down the SENSOR key press the SCAN 11 key You may now let up on the SENSOR key 3 To change the sign if in the COPYRIGHT 2 88 LSCI 9215 Capacitance Input Card upper display hit the 44 key while still holding down the SCAN t key Similarly to change the sign if in the lower display hit the key while still holding down the SCAN 11 key 4 Now let up on the 44 key or key and then the SCAN 11 key You should press the SENSOR key to make sure that the sign is as desired 9215 6 3 Selection of the Sign of the Temperature Coefficient via the Computer Interface TO select the sign of the tempera ture coefficient via the IEEE interface check the and BC4C9 commands in the instrument manual 9215 7 PRINCIPLE OF OPERATION The 9215 15 configuration provides a charging current switched at a frequency of 5 kilohertz The frequency is precisely controlled by a crystal oscillator The operation of the 9215 150 is identical except that the frequency is 1 kilohertz The charging current produces a sawtooth voltage waveform with peak to peak voltage of about 7 volts Another voltage of precise amplitude is generated which has a duty cycle
127. ate This action is similar to turning the instrument OFF and then turning it back ON except that it occurs in milliseconds rather than seconds and the DRC 91C does not go through the power up display se quence 4 7 5 The W2 Data String For the case of W2 the data string would have the following format Z0 M2 T1 TERMI1 TERM2 where the ZO M2 and Ti are defined in Table 4 6 4 7 6 The WI Data String This Data String gives the input cards present 9210 9220 9215 9305 9317C or 9318C in Input A and B whether the analog option is presentand the interface option is present A typical data string would be A 9220 P2 B 9318C 1 8225 2 8223 3 8229 which indicates 9220 card configured as a 100 ohm platinum input for Input A a germanium carbon glass input for Input B a linear analog option in Option Slot 1 a RS 232C option in Option Slot 2 and a Scanner Card option in Option Slot 3 4 8 SELECTION OF SET POINT UNITS INPUT UNITS DISPLAY SENSOR AND RESOLUTION Table 4 7 4 8 1 Units for Set Point The FOC Command The FOC command sets the tempera ture or sensor units for the set point Sensor units volts ohms or nanofarads are selected automa tically by the input card type COPYRIGHT 3 88 LSCI Model DRC 91C Consequently the command for selecting sensor units for control is FOS Temperature units selected with the same command with K C or F substituted for S Note that only on
128. ate the 8225 Analog Output 1 Remove the three top panel screws and slide the panel off 2 Connect the DVM plus lead to the J3 MONITORS connector pin C and the minus lead to pin D 3 With the load resistors or the voltage standard to simulate the input sensor go to a low temperature and adjust the trimpot labeled Z for Zero on the calibration cover until the voltmeter reading corresponds to 10 mV K Go to a high temperature and adjust the trimpot labeled S for Span 4 Repeat procedure in paragraph 3 until there is no further Zero or Span adjustment required 5 Install the top panel 8225 7 REPLACEABLE PARTS Included in this Section is Figure 8225 1 It includes the Model 8225 Analog Output schematic replaceable parts list and illustrated component layout Refer to the manual for ordering information COPYRIGHT 12 87 LSCI B 312 83 01A CONTROL cs SAMPLE REPLACEABLE PARTS LIST MODEL 8225 ANALOG OUTPUT OPTION ITEM LSCI Part NO Number 104 524 IC PORT EXPANDER 104 425 IC 4 DIGIT DAC 104 001 IC Description MFR PART NO 255 5_ DAC71 CCD V __ 5 OPTION SLOT AD2 O 1082 AD3 CONTROL CS JUMPER TO SELECT SAMPLE OR CONTROL ANALOG OUTPUT V P8255A 5 C2 68 C42 5 D lt 58 16 DAC 71 CCD V
129. ater display is shipped from the factory reading the percent of power out If the heater is 10 ohms then at 100 percent output current the heater will have 1 amp through it and 10 volts across it If the heater bar graph is reading 50 then the instrument is deliver ing 5 watts 0 707 amps and 7 07 volts to the 10 ohm load If the unit is reading in current a read ing of 50 will mean 2 5 watts 0 5 amps and 5 volts The heater dis play can be changed from power to current by switching internal dip switch 57 1 5 5 7 Checking Gain Reset and Rate Check the operation of the Gain Rate and Reset as follows 1 Place a dummy load into the selected sensor input a 50K to 100K for a diode b Short vt to V for 9317C or 9318C Input Card c 10 capacitor for 9215 Input Card 2 Place 10 ohm 10 watt greater resistance load on the heater terminals 3 Set the Display Units to Sensor Units volts ohms or nanofarads a If 9210 3 20 3 enter a volt age 0 01 volts less than the display b If 9317C or 9318C enter a resistance of 1 ohm for the set point If 9215 enter 11nF set point 5 4 Model DRC 91C 5 5 7 1 Gain Enter a gain value Ihe heater display should now indi cate that power is being delivered to the heater The amount of power is a scaled factor of the error signal times the gain Sensor voltage Setpoint voltage Gain If the setpoint temperature is increased o
130. atures are above and often well above room temperature There at least five factors which crucially affect temperature control performance when one compares a cryogenic system with that existing inside a furnace for example 1 The values of heat capacity lower and thermal conductivity often higher are such that much shorter thermal time constants are the rule at low temperatures 2 The temperature sensor used in a furnace is almost always one of a variety of thermocouples with sensitivities in the 10 100uV C range In the cryogenic regime resistance thermometers both metallic and semi conductive diode and capacitance thermometers provide from one to three order of magnitude higher sensitivity 3 heat input for furnaces is almost always derived from a line frequency source and is controlled by relays variable transformers saturable reactors or SCRs Experiments performed in a cryostat usually involve low level signals and hence require a low noise background For that reason ripple free direct current usually controlled by a series transistor bank should be used to power the heater 4 traverses the cryogenic regime from the liquid helium range up towards room temperature there can be quite large variations in both the thermal time constants and thermometer sensitivities 5 case of the furnace in which the load does not experience large endo or exothermic reactio
131. atus Register on response to a serial poll or if the reading is no longer valid These functions can be inhibited by turning their corresponding bits in the Status Register mask off 4 11 2 2 Status Report 2 The Control Channel Limit When the control sensor reading gets within the chosen limit from the set point bit 2 is set in the Status Register If the Service Request is enabled this bit being COPYRIGHT 3 88 LSCI Model DRC 91C set will cause the DRC 91C to pull the SRQ management low to signal the BUS CONTROLLER As with all of the Status Reports this bit is reset to zero upon reading the Status Register The bit will not revert to zero if the control sensor difference from the set point later exceeds the limit selected The control channel limit is entered using the Q command See Section 4 11 4 2 This function can be inhibited by turning off bit 2 in the Status Register mask 4 11 2 3 Status Report 3 Display Sensor Channel Change Bit 3 of the Status Register is set when a channel change occurs for the Display If the Service Request is enabled this bit being set will cause the DRC 91C to pull the SRQ management low to signal the BUS CONTROLLER This Status Register bit is reset to zero upon reading the Status Register This function can be inhibited by turning off the bit 3 in the Status Register Mask 4 11 2 4 Status Report 5 Overload Error Indicator If the display has an overloa
132. brated DT 500 or DT 470 Series Sensors accommodated with an 8000 Series Precision Option The 9210 6 configuration will accommodate diode sensors TG 120 series with voltages between 0 and 6 5535 volts calibrated sensor and 8001 Precision Option required for the DRC 91C 93C to read accurately temperature 9210 3 can be converted to 9210 6 configuration by switch on the 9210 Diode Input Option Card This configuration will also read DT 470 and DT 500 series sensors but with reduced resolution and accuracy See Table 9210 1 9210 3 SPECIFICATIONS Specifications for the Model 9210 Diode Input Card are given in Table 9210 1 The card can be configured by the user as either a 3 volt 9210 3 or 6 volt 9210 6 card COPYRIGHT 12 87 LSCI Table 9210 1 9210 Diode Card Sensor ordered separately DT 470 series DT 500 series and TG 120 series from LSCI as well as any other diode sensor See Lake Shore Diode Sensor brochures Temperature Range Dependent on Diode Sensor See Sensor brochure Sensor Excitation DC current source 10 microamperes 40 0055 AC current noise less than 0 01 of DC current Compliance voltage 7 volts minimum Maximum Sensor Power Dissipation 20 microwatts 8 4 2 for DT 470 Series 25 microwatts 8 4 2K for DT 500 Series Dissipation under other conditions is product of Sensor Excitation Current and developed sensor voltage 9210 3 Input Voltage
133. cedure to eight calibration switches CAL 8 through CAL 1 Refer to Table 9317C 9318C 2 for the hardware Switch definitions of CAL 8 through CAL 1 References are made to test points adjustments and calibration Switches that are labeled on the calibration cover Use the following procedure to calibrate the 9317C 9318C Resistance Input Card 1 Remove the three top panel screws and slide the panel off 2 Configure the input that contains the 9317C 9318C as the SAMPLE input only and make the units R Turn off Digital Filtering and Thermal Cor rection DIP switches of the appropriate SENSOR ID switches 2 and 3 to the OPEN OFF position for the DRC 91C or disable from the front panel on the DRC 93C 3 Current Source Zero Connect the 10K 9317C ohm precision resistor across the I and I pins of the Resistance Input Card input connector and enable both CAL 8 and CAL 7 of the 9317C 9318C 6 4a Model DRC 91C 93C card Attach the plus and minus leads of the DVM to the test points marked V and V respectively of the 9317C 9318C PCB and adjust the trimpot marked IZ so that the voltage reads as close to zero as possible If this voltage is not close to zero it may effect the sensor current setting Consequently this operation should be performed before any current calibrations are performed Disable CAL 7 and continue Note that CAL 8 will remain enabled for all calibration operations Voltage Match or Span
134. cesses are complete whether the channel was changed or a limit overload or error encountered The Status Register Mask is provided so that the Status Request interrupt and 4 17 Section IV undesired Status Reports can be inhibited Reading the Status Register resets the Status Register to all zeros so that only new status reports will be registered by the DRC 91C Thus through the SRQ management line and the Status Register the DRC 91C is able to signal Status Reports on five conditions immediately to the BUS CONTROLLER It is possible to disable the DRC 91C SRQ line thereby preventing the DRC 91C from interrupting the BUS CONTROLLER However the BUS CON TROLLER can still read the Status Register to determine appropriate instrument conditions 4 11 1 The Service Request The Service Request Message is independent of all other IEEE 488 activity and is sent on a single line called the SRQ line When the Service Request is sent and more than one instrument on the Bus has the capability to send this message the BUS CONTROLLER must decide which instrument is sending the request This is done by conducting a Serial Poll of the instruments on the Bus The instrument polled responds by sending a Status Regis ter The Status Register indicates whether the device has requested service and if so for what reason Once the reading on a given channel becomes stable or valid a service request is issued by the DR
135. convenient ly monitor power applied to his system accommodate systems which require lower heater power the maximum output can be at tenuated in three steps of a decade each When greater output power is required the optional W50 and W60 output stages can provide either 50 or 60 watts respectively An IEEE 488 interface is standard in the DRC 91C This interface can be used to remotely control 11 front panel functions When two input cards are used data from both inputs is available via the interface 1 3 SPECIFICATIONS Instrument specifications are listed Table 1 1 These specifications are the performance standards or limits against which the instrument is tested 1 4 OPTIONS The options for the DRC 91C Controller are listed in Section Three option ports are designed into the DRC 91C The options are field installable by the user gt 822x series options can be factory installed in the DRC 91C or field installed at a later time The 8223 RS 232C Interface Option operates similar to the IEEE 488 interface The Model 8225 Analog Output option is available to provide a linearized analog output 1 3 Section I of 10mV K independent the display temperature units If the display is in sensor units the output for diodes is 1V V for 100 ohm platinum 10mV ohm for 1000 ohm platinum 1mV ohm for rhodium iron 100mv ohm and for capaci tance units 100mV nF and 10mV nF Table 1 1 Input
136. ction contains general information for the Lake Shore Cryotronics Inc DRC 91C Tempera ture Controller Included is an instrument description specifica tions instrument identification option and accessory information 1 2 DESCRIPTION The DRC 91C Temperature Controller is a microprocessor based instru ment which provides true analog control It is capable of scanning multiple sensor inputs and display ing temperature with up to 5 digits of resolution in K C or F or sensor units volts ohms or nanofarads to five digits The DRC 91C can be used with either 1 or 2 input cards When two input cards are used these cards can be different to allow two separate types of sensors to be used with the controller The dual sensor input with the optional 8229 Scanner Conversion Card expand the input capability of the DRC 91C to up to 6 input sensors Depending on the input COPYRIGHT 1 88 LSCI INFORMATION option selected the DRC 91C handles silicon 9210 3 or 9220 3 or the patented Gallium Aluminum Arsenide 9210 6 or 9220 6 diodes platinum or rhodium iron resistors 9220 series germanium or carbon glass resistors 9317C 9318C or capacitance sensors 9215 With or without the 8229 Scanner Card the DRC 91C can be set to scan automatically with in dividual dwell time of 1 to 99 Seconds per channel or stepped to any available input and held there Setting the dwell time to zero causes a particular c
137. d Figure 9305 2 Model 9305 REPLACEMENT PARTS LIST MODEL 9305 INPUT MODULE BOARD LSCI PART WUNBER 113 180 aliu dL 101 s ds e pnm ae d 109 M 102 064 2 DIODE SWITCHING Qype mme nm tei Noe dementia da edm o m rt aeu et rm M S35 THERACCOUMLE HODULE VR Wurm an nic ERE d 1 ec 88 stax uU Figure 9305 3 Model 9305 Thermoc ouple Input Card Module E Model DRC 91C 93C 9317C 9318C Input Cards 9317C 9318C RESISTANCE INPUT CARD 9317C 9318C 1 INTRODUCTION This section contains information pertaining to the Model 9317 9318 Resistance Input Card Included is description specifications installation operation and maintenance information 9317C 9318C 2 DESCRIPTION The Model 9317 9318 Resistance Input Card is designed to be installed in a DRC 91C 93C to convert either Input A or Input B or both with two cards to accommodate sensors where the voltage ievel must be kept at levels on the order of 1 or 10 millivolts and where thermal voltage may exist The 9317C 9318C can be used with germanium carbon glass or carbon resistors or any other negative temperature coeffi cient resistors Both cards read in ohms from a full scale reading of 10 ohms with 1 milliohm resolu tion to a full scale reading of 10 000 chms with 0 1 ohm resolution for the
138. d condition on any selected channel or an error occurs then bit 5 of the Status Register is set and a Service Request is issued if enabled This Status Register bit is reset to zero upon reading the Status Register This function can be inhibited by turning bit 5 off in the Status Register Mask COPYRIGHT 3 88 LSCI Section IV 4 11 2 5 When operating without the Service Request It is still possible for the BUS CONTROLLER to read the Status Register Service Request is inhibited by turning off the SRQ bit bit 6 in the Status Register Mask However it must be understocd that certain bits in the Status Register are continually changing The Status Reports for the Overload Error Display Data Ready and Control Data Ready are continuously updated to reflect current instrument status The Channel Change and Control Channel Limit once en countered are latched set to 1 and remain latched until the Status Register is read 4 11 3 The Status Register Mask The Command The Status Reports listed above may not be desired or perhaps only a few are of interest The Status Register Mask is provided to allow the user to select whether he wants a given Status Report or not The various bits of the Status Register Mask enable the various Status Reports The bits in the Status Register Mask have the same bit position as the bits in the Status Register Only those bits which are allowed by the Status R
139. d in modifying one of the NOVRAM locations 01 error will be displayed and instrument operation is halted Err02 error is displayed if the unit detects a NOVRAM hardware problem 4 28 COPYRIGHT 3 88 LSCI Model DRC 91C Section IV Table 4 17 Sensor Curve Information Table Output Format N4N4N4N4 BYTES FREE H H gt H3H IS NEXT LOCATION 00 31 1040 DRC D 01 31 10 0 DRC E1 02 31 LEAO 10 03 31 1250 DIN PT 04 31 2000 10 05 31 20BO RESVRD Pm C1C2 4 1 2 2 1 2 4 1 2 1 2 1 2 C1C2 C1C2 2 2 1 2 1 2 1 2 2 2 1 2 2 2 1 2 1 2 1 1 2 122 122 1 2 1 2 1 2 1 2 1 2 1 1 2 1 2 1 2 1 2 1 2 1 2 1 5 152 162 1 2 162 1 2 162 1 2 1 2 4 C1 Co 1 2 1 2 1 2 1 2 1 2 1 2 1 2 162 1 2 162 1 2 162 1 2 6162 TERM1 2 A minimum of 321 Characters when only the 6 Standard Curves are present and a maximum of 805 Characters
140. d it would be good practice to read out the changed table by means of the XDT command and update Table 3 4 1 2 is the hex Remote Position 00 thru 1 NN is the decimal curve number 00 thru 31 Section IV Table 4 19 Input Card 9210 20 3 9210 20 6 9215 9317C 9318C 9220 1 Voltage Capacitance Resistance Resistance Resistance Model DRC 91C Conversion of Raw Units Data for the XC Command Units Conversion Input range is 0 00000 to 6 55350 volts No conversion is necessary No conversion to temperature is allowed Input range is 1 to 104 n for the 9317C 1 to 10 for the 9318C Input must be in Log R where 1 0 would look like 0 00000 and 10 n would look like 5 00000 Input range is 0 00 to 299 99 ohms 0 00 ohms looks like 0 00000 and 299 99 ohms looks like 2 99990 0 01 times Input range is 0 0 to 2999 9 ohms 0 0 ohms looks like 0 00000 and 2999 9 ohms looks like 2 99990 0 001 times R Input range is 0 00 to 100 00 ohms 0 00 ohms looks like 0 00000 and 100 00 ohms looks like 3 00000 0 03 times R COPYRIGHT 3 88 LSCI Model DRC 31C Section V SECTION V MAINTENANCE 5 1 INTRODUCTION This section contains information necessary to maintain the Model DRC 91C General maintenance fuse replacement line voltage selection and performance testing is contai ned in this section 5 2 GENERAL MAINTENANCE Clean the DRC 91C periodically to remove dust
141. d to the V Buffered Sensor Output Signal pin for the appropriate Input Card and the minus lead to the V pin on the MONITORS connector Connect the precision voltage source across the E V and D V pins of the five pin input connector for the appropriate input Set the standard to 1 5000 volts and adjust the trimpot marked the calibration cover until the DVM reads as close to 1 5000 volts as possible for the 9210 3 configuration and adjust the value to 0 68666 volts for the 9210 6 configuration COPYRIGHT 12 87 LSCI 9210 Diode Input Card 4 Calibrate the A D Converter Verify that the Display selects the desired Input Card and that the units selected are V Set the standard to 1 5000 volts for the 9210 3 and adjust the trimpot marked A D until the display reads 1 5000 V Check linearity by inputting 2 0000 and 1 0000 volts and verify that the unit displays those settings within 0 0001 volts 5 0000 and 1 0000 volts for the 9210 6 If this specification is not met check the Technical Service Guide for further instructions 5 Install the top cover panel 9210 7 SENSOR CURVE INFORMATION Sensor Curve data for use with the 9210 Diode Input Card must be put in table form consisting of voltage and temperature points with the voltage in ascending voltage order Refer to Section 4 of this manual for a discussion of how the data must be formatted for entry into the unit over the remote interfaces and to App
142. d with the DT 470 sensor special attention should be given to the following details The DT 470 is designed to operate at a constant current of 10 microamperes while the voltage variation with temperature is monitored Therefore the accuracy of the temperature measurement depends directly onf the specifications of the current source and the voltmeter A current source operating at the level of 10 20 01 microamperes 0 1 gives a nominal temperature uncertainty of 10 millikelvin 0 01 K which is probably suitable for most applications The voltmeter resolution required can be estimated from the sensitivity dV Dt of the DT 470 Temperature K Sensitivity mV K 305 2 4 77 1 9 4 2 33 Multiplying the above sensitivity by the desired temperature resolution in kelvin will give the required voltage resolution in millivolts The static impedance of the DT 470 sensor operating at a 10 microampere current is the order of 100 000ohms Therefore the input impedance of the voltmeter must be significantly larger than this to avoid measurement errors Voltmeters with input impedances of greater than 109 or 1010 ohms should be used Good quality instrumentation must be used and all instrumentation and wiring should be properly grounded and shielded Temperature measurement errors will result if there is excessive AC noise or ripple in the circuitry Further details can be found in the article by Krause and Dodrill given in the references NOTE All
143. d with which input the sensor will be associated if remote 3 2 Model DRC 91C operation is used 3 5 CONTROL FUNDAMENTALS An application note entitled Fundamentals for Usage of Cryo genic Temperature Controllers is included as an appendix in this manual and should be read in detail if you are not familiar with cryo genic temperature controllers 3 6 CONTROLS AND INDICATORS Figures 3 1 and 3 2 identify the DRC 91C displays annunciators controls and connectors The identification of each item is key ed to the appropriate figure FRONT PANEL DESCRIPTION 3 7 POWER ON Before connecting AC power to the DRC 91C make sure the rear panel voltage selector is set to cor respond to the available power line voltage Be certain the correct fuse is installed the instrument 3 7 1 POWER UP SEQUENCE Immediately on POWER ON the 91 runs through a power up sequence as follows 1 The Display Block indicates 8 8 8 8 8 in both the upper and lower displays and the Heat er 5 indicates 188 addition all the annunciators and LED s are turned on The annunciators Al A2 A3 A4 are displayed in a column on the left of the dis play The LED s include DISPLAY SENSOR A 171 scan CONTROL SENSOR A and B as well as six sets of units for both DISPLAY SENSOR and CONTROL SENSOR HEATER POWER RANGE from OFF to MAX LOCAL and REMOTE COPYRIGHT 12 87 LSCI Model DRC 91Cc Section III Figure 3 1 DRC 91C
144. data points are entered the charac ter terminates the Sensor Curve input Following the input of the to indicate to the unit that the there are no more data points it determines and stores whether the curve is a positive or negative temperature coefficient curve Based on temperature coefficient the unit then stores the curve end points For a negative temperature coefficient curve the first end point is 0 00000 499 9 and the last end point is 6 55360 000 0 Fora positive temperature coefficient curve the first end point is 0 00000 000 0 and the last point is 6 55360 999 9 Therefore the minimum number of data points which the user can input for a curve is 1 which would result in a 3 data point curve and the maximum number of data points is 97 which would result in a 99 point curve The XC information must be output to the unit as one very long character string The first character of the 18 character management string indicates the type of breakpoints to be entered If the character is ZL then the unit performs Lagrangian calculations the data If the character is anything else the unit performs Straight Line interpolation on the data See Appendix B for a description of the difference between the two In addition sensor type and tempera ture range is included in this 18 characters as well Curves 06 thru 31 are stored in Non Volatile RAM NOVRAM where the first 0200 hex bytes are r
145. dc current independence in Fig 4 and the frequency independence in Figs 6 and 7 The data taken at 305 K have not been shown as the results are qualitatively very similar to the 77 K measurements and can be adequately described by the mathematical model which is presented below One surprising aspect of the data acquisition was how well the signal processing in the voltmeter could hide even high ac levels in the dc measurement modes For example operating at 10 dc and 77 with a rms noise level of mV gives a dc voltage offset of about 1 5 mV which is about a 0 6 K temperature error When reading the voltage signal using the filtering and integrating capabilities of the HP 3456A the dc voltage reading is stable to better than 20 02 mV 8 mK Application Notes 15 Lake Shore Cryotronics This stability gives a deceptive view of exactly how accurate the temperature measurement really is and emphasizes the importance of checking all aspects of a measuring system The measured offset voltages shown in Figs 4 and 6 can be understood by using the well known result from p n junction theory ls exp eV nkT 1 1 where the forward current through the junction the reverse saturation current e the electron charge V the voltage across the junction k Boltzmann s constant and T the absolute temperature n is a parameter depending on the location of the generation and recombination of the electrons and hole
146. de sensor These curves introduce the concept of loop gain dP dT watts kelvin which includes the gain of the sensor as well as that of the deviation amplifier and power output stage As the transition in temperature 1 from above 30 kelvin to below 30 kelvin is made the loop gain is increased by a factor of 20 because of the increased sensitivity of the silicon diode thermometer Because of noise and thermal phase lag the deviation amplifier gain will normally have to be reduced by the same factor so that the 100 200 300 loop gain remains relatively constant 50 mV kelvin 2 5 mV kelvin Temperature kelvin In order to maintain any desired temperature above that of FIGURE 4 Idealized curve for Lake Shore Cryotronics Inc DT the cryogen in a cryogenic system of course some level of 500 Series silicon diode temperature sensors heater power must be supplied by the controller We have seen in Figures 2 and 3 that a non zero temperature error signal is necessary to produce an output and that the magnitude of the error or temperature offset is a function of the power output level and the loop gain Let us demonstrate the nature of the offset also called droop with an example Heater Output Voltage in Volts P 7150 V Assume that a system sample block the mass whose temperature is to be controlled has a finite heat capacity but that its thermal conductivity is infinite as is the thermal conductance be
147. degrees Celcius COPYRIGHT 6 88 LSCI 9305 Thermocouple Input Card An Offset Adjustment is provided adjacent to the Terminal Block This adjustment will zero out small voltage offsets that result from sensor lead attachment and differences from the internal curve 9305 6 1 Display Operation Digitized thermocouple and secondary sensor voltages on the 9305 card are sent to the main board of the controller The secondary sensor temperature is computed from its voltage thermocouple voltage corresponding to the secondary sensor temperature is calculated If correction is selected the compensation value is added to the thermocouple voltage Corrected voltage in millivolts is then used as a display value or converted to Celcius degrees Fahrenheit degrees or Kelvin for display 9305 6 2 Control Operation Control operation begins when the operator enters a Setpoint voltage in millivolts If the Setpoint is in temperature the main board computes an equivalent voltage using the built in Thermocouple table The main board microprocessor then checks to see if Reference Junction Compensation is enabled If the Reference Junction Compensation is disabled a signal which is 200 times the digital value of Setpoint voltage is applied to the Setpoint D A to obtain the Setpoint voltage for control If the Reference Junction Compensation is enabled a voltage corresponding to the Terminal Block temperature is subtrac
148. dependent on the charging time of the capacitor This waveform is averaged and filtered to produce a positive DC voltage proportional to the capacitance This DC voltage is sent to a 16 bit A D converter on the card The A D converter has a resolution of 50 microvolts and a full scale input voltage of 3 0000 volts With the 9215 15 Configura tion the 3 0000 volts corresponds to a capacitance of 30 nanofarads and on the 9215 150 configuration to 150 nanofarads The digitized 9215 5 9215 Capacitance Input Card value is converted to a serial data string and transferred to the main microprocessor using optical isolation A relay on the Card configures the sensor voltage negative or positive based on the temperature coefficient sign selected by the user Section 9215 5 That voltage is buffered and transferred to the rear panel MONITORS connec tor for external monitoring as well as to the main board control circuitry 9215 8 CALIBRATION The 9215 was calibrated to specifi cation prior to shipment The card meets specification for operation either in the 9215 15 or 9215 150 configuration by simply pressing the switches located on the card This Section provides information to permit recalibration if needed NOTE Calibration for zero capacitance may be required to meet accuracy specifications if your sensor lead capacitance or stray capacitance is excessive The following equipment is used to calibrate the 9215
149. e given in Table 9220 1 of this manuai The card can be configured as a 9220 3 or 9220 6 diode card a 9220 P2 or 9220 P3 platinum card or a 9220 R1 rhodium iron input card COPYRICHT 12 87 LSCI Table 9220 1 Input Card 9220 3 See 9210 3 specifications 9220 Configurable 9220 6 See 9210 6 specifications Sensor ordered separately Platinum RTD sensor PT 100 series or any other 100 ohm or 1000 ohm platinum sensor 27 rhodium iron sensor See Lake Shore Sensor brochures Temperature Range Dependent on Sensor See Sensor brochure RTD Sensor Power Dissipation Depends on Sensor Resistance Dissipation is the product of sensor excitation current squared and the Sensor resistance 9220 P2 100 ohm platinum Current Excitation 1mA 0 005 Resistance Range 0 00 299 990 Resolution 0 005 ohms Accuracy 0 01 ohms Display Resolution 5 digits Displays 0 00 to 299 99 ohms 9220 P3 1000 ohm platinum Current Excitation 0 1mA 0 005 Resistance Range 0 0 to 2999 9 Resolution 0 05 ohm Accuracy 0 1 ohm Display Resolution 5 digits Displays 0 0 to 2999 9 ohms 9220 R1 27 ohm platinum Current Excitation 3 mA 0 005 Resistance Range 0 000 to 99 9990 Resolution 0 003 ohm Accuracy 0 003 ohm Display Resolution 5 digits Displays 0 000 to 99 999 ohms Equivalent temperature accuracy is a function of sensor type sensitivity and Precision Option 9220 1 9220 Input Card
150. e PID control parameters and for deriving the set point signal This approach is used in most of the Lake Shore Cryotronics Inc controllers 6 Application Notes Lake Shore Cryotronics Inc For Further Reading 1 E M Forgan On the Use of Temperature Controllers in Cryogenics Cryogenics 14 1974 pp 207 214 This is a cogent discussion of the interaction between the electrical and thermal response times in a typical cryogenic control system The mathematical analyses are straightforward and relatively easy to follow A series on process Control published in the journal Measurement amp Control Part 3 On Off and Proportional Control September 1984 pp 165 170 Part 4 Reset and Rate Control October 1984 pp 133 145 Part 5 Selecting the Mode of Control December 1984 pp 132 136 Some of this material has appeared in Principles of Temperature Control available from Gulton Industries West Division Unlike reference 1 the discussion is not related to cryogenics but temperature control system principles are briefly and clearly explained C L Pomernacki Micro Computer Based Controller for Temperature Programming the Direct Inlet Probe of a High Resolution Mass Spectrometer Review of Scientific Instruments 48 1977 pp 1420 1427 W M Cash E E Stansbury C F Moore and C R Brooks Application of a Digital Computer to Data Acquisition and Shield Temperature Control of a High Temperature Adiabatic Calo
151. e above room temperature stable control can be maintained by digital systems updating temperature only once or twice a second This is for the same reason that ON OFF controllers are successful in these cases the large thermal time constants of the controlled environments However as discussed in Section the time constants are much shorter cryogenic systems so much so that temperature can and frequently does change at a rate which exceeds the sampling frequency of a typical digital cryogenic controller approximately 2 Hz A good example is a mechanical refrigerator based on the Gifford McMahon cycle At 10 kelvin and below these refrigerators unloaded often have a peak to peak variation in temperature which exceeds 1 kelvin at a nominal 3 Hz frequency That variation represents an inherent disadvantage which is difficult for the all digital system to overcome since the sampling rate is lower than the frequency of the temperature variation The Sampling Theorem of Electrical Engineering implies that no sampled data control system can be stable unless it is sampled at a rate which exceeds at least twice the highest frequency variation within the system Some designers of all digital controllers for cryogenic temperatures appear to have overlooked this sampling rate problem There are also examples of digital controller which fail to achieve optimum performance because of the design of their output stage heater power is varied on a cyclica
152. e choice of sensor units volts ohms or nanofarads is available which is dependent on the control input and the input card type and configuration selected 4 8 2 Units for A and B Inputs The and F1BC Commands Ihe A input units and the B input units may be set independently by the commands F1AC and F1BC4 respectively units are tied to the input and not to the display Sensor units are selected auto matically by the input card type Consequently the command for selecting sensor units is F1AS or F1BS Temperature units are selected with the same command with K C or F substituted for S for either input 4 8 3 Display Sensor Selection The F2C N Command The sensor to be selected for display can be changed by the F2C N command This command is important with a scanner card because it chooses which sensor on Input A will be read over the bus when data is output from the instrument 4 8 4 Resolution for A and B Inputs The F3AN and F3BN4 Commands The resolution for the A input and the B input can be set independently with the and F3BN4 commands The resolution is tied to the A and B inputs and not to the display The quantity Nj is a number 0 through 4 where 0 for resolution of XXX 1 for a resolution of xxx x 2 for a resolution of xxx xx 3 for a resolution of xx xxx 4 for a resolution of COPYRIGHT 3 88 LSCI Section IV 4 8 5 The A and B SENSOR ID Infor
153. e four screws that secure the calibration cover to its clips and remove the cover 3 If the 9317C 9318C is to replace an existing Input Card unplug the Input Card which is to be replaced Disconnect the wiring harness mating connector by lifting the locking tab on the Input Card and gently pulling on the body of the wiring harness mating connector 9317C 9318C 1 9317C 9318C Input Cards Model DRC 91C 93Cc Table 9317C 9318C 1 Specifications 9317C 9318C Resistance Input Cards Input Range 9317C Less than 1 ohm to 10 000 ohms with a resolution of 1 part in 10 000 and an accuracy of 0 1 of reading for resistances from 1 to 1 000 ohms and 0 5 of range for resistances from 1 000 to 10 000 ohms 9318C Less than 1 ohm to 100 000 ohms with a resolution 1 part 10 000 and an accuracy of 0 05 of reading for resistances from 10 to 10 000 ohms and 0 25 of range for resistances less than 10 ohms and from 10 000 to 100 000 ohms Sensor Excitation Current range is from 0 1 microampere to 1 milliampere The current is varied automatically to maintain the voltage across the sensor at 1 millivolt for the 9317C and 10 milli volts for the 9318C Current polarity is periodically reversed to allow for automatic digital correction for thermal EMFs in the sensor connections and leads Temperature Range Depends on sensor type used Sensor resistance scales from 1 to 10 000 ohms 9317C or 100 000 ohms 9318 can be accommodated
154. e in HP Basic illustrate the commands associated with obtaining output data from the DRC 91C The addition of the MO command returns the instrument to front panel control where it stays even when data is requested from the 91C by the HP computer 10 DIM A 19 20 OUTPUT 712 WOMO 30 ENTER 712 A The following information is sent across the bus in the 488 format as a result of the above software commands Command mode sent U W O M O CR LF Data returned 5 123 45 123 42 123 40 CR LF Data returned 91C s Talk Address BUS CONTROLLER s Listen Add Universal Unlisten Command The data above indicates that the display temperature is 123 45K and that the set point is 123 40K 4 23 Section IV Model DRC 91C Table 4 15 DRC 91C Output Data Statements Request Output of Instrument Data WS Sample Sensor Data N1N2N3 N4Ns 8 Characters plus up to 2 Terminators where the N4 Ng variations are the same as for WO see below WC Control Sensor Data NgN Ng NgN490 8 Characters plus up to 2 terminators where the Ng N1g variations are the same as for WO see below Set Point Data 11 12 13 4 5 8 Characters plus up to 2 terminators where the 11 15 variations are the same as for WO see below WO Sample WS Control Sensor WC and Set Point WP Data N4NoN5 NgN5Ng 10
155. e last character to be displayed is number 460 since the Terminators CR LF have to input but not displayed This results in the following display 00 STANDARD DRC D N 31 0 00000 499 9 0 19083 365 0 0 24739 345 0 0 36397 305 0 0 42019 285 0 0 47403 265 0 0 53960 240 0 0 59455 220 0 0 73582 170 0 0 84606 130 0 0 95327 090 0 1 00460 070 0 1 04070 055 0 1 07460 040 0 1 09020 034 0 1 09700 032 0 1 10580 030 0 1 11160 029 0 1 11900 028 0 1 13080 027 0 1 14860 026 0 1 07200 025 0 1 25070 023 0 1 35050 021 0 1 63590 017 0 1 76100 015 0 1 90660 013 0 2 11720 009 0 2 53660 003 0 2 59840 001 4 6 55360 000 0 The N indicates that the silicon diode is a negative temperature coefficient device For the platinum curve 03 which is a positive temperature coefficient device a P will appear in that position Model DRC 91c 4 14 3 The XDA Command Ihe XDA command asks for the output of the Sensor Curve Information Table as well as all the Sensor Curves stored in the unit When the command is used the 91 will output the Information Table formatted as in Table 4 17 followed by a comma in place of the Terminators followed by each Sensor Curve in ascending order with a comma between each Sensor Curve in place of the Terminators as in Table 4 18 until all the curves have been output followed by the Terminators The information is output as one very long character string 4 14 4 The Command
156. e observed 20 S123 4P45I30D25R4W1 CR LF The Universal Unlisten Command is sent so that no other instru ments on the Bus will eavesdrop on the Bus and assume that the data being sent is for their attention The DRC 91C s Talk Address L is sent to unaddress existing Note that the BUS CON TROLLER could have designated another instrument as the TALKER Therefore to keep the format consistent it must send a Talk Address even when the DRC 91C is going to be that TALKER The Listen Address must be sent to tell which instrument on the Bus is to receive the Data String Note that TERMI TERM2 have been indicated to be CR LF carriage return line feed these are the correct terminators for the HP computer example Note that the string P45I30P40 would result in a gain of 40 and an integral value of 30 i e only COPYRIGHT 3 88 LSCI Section IV the last value sent over the bus for that program code will be entered after the appropriate terminators have been sent over the pus 4 12 1 Output Data Statements Ihe DRC 91C s Output Requests for Data Statements are summarized in The DRC 91C will always respond when asked to talk with the last command sent to it i e if WO is sent once then the 91C will always output the WO information whenever it is asked to talk as long as it has not received another output data statement 4 12 2 The WO Data String The following exampl
157. e output power check to see that U13 on Figure 91 1 the IM317HVK is tightly screwed into its heat sink It is on standoffs near the fan in the left rear of the unit Confiqure the DRC 91C as in Section 5 5 6 2 Verify that there is heater current going to the load resistor Next measure the analog out signal to be sure the PID circuits are operating correctly The analog out signal can be measured at TP28 Gnd at TP1 this is a 51 tive value that varies from 0 7 3 volts as the gain setpoint or reset values are changed then the circuit is probably operating cor rectly Now measure the voltage across from TP19 to TP21 The voltage should vary from O to 1 volt as the analog out signal var ies from O to 7 3 volts As the gain or manuali heater is increased the analog signal will increase and the voltage between TP19 and TP21 will increase If the voltage stays at 0 Volts then U45 or U46 is probably bad as long as the raw V TP21 to TP6 is close to 28 volts The V be checked by measuring approximately 28V from TP21 to TP1 The V value is over 50 Volts if a W50 watt option is installed in a DRC 91C or if the resistor setting is 50 ohms on the DRC 93C If a W60 Watt option is installed the V voltage should be approximately 44 volts If the Voltage from TP19 to TP2 is 2 7 Section V correct and there is no heater power on any range than U47 or U48 are probably bad and both should be replaced
158. e pin configuration for the IEEE 488 connector Even though the Input contacts are not on the J9 connector the sensor signal from Input is routed through the 8229 Scanner COPYRIGHT 12 87 LSCI Channel Channel Channel Shield Shield Shield Channel Channel Channel BO LSB Bi Out B2 MSB provides four Shield 24 Digital Grnd In essence the 38229 routs the sensor signals from all five Input channels to the A Input Card The Al through 4 8229 inputs are designed for four lead measurements and have independent pairs of current and voltage leads The current leads have a make before break switching action and the voltage leads break before make The BO through B2 outputs 29 ECD representation of the channel selected with BO being the least significant bit and B2 the most significant bit 0 represents logic LO and a 1 logic HI with respect to the Digital Ground on J9 Logic 000 represents channel 0 001 channel A1 010 cbannel A2 011 channel A3 and 100 represents channel B2 B and respectively 8229 3 SPECIFICATIONS Specifications for the Model 8229 Scanner Conversion Option are given in Table 8229 2 8229 1 8229 Scanner Conversion Option Table 8229 2 Model 8229 Scanner Conversion Specifications Number of Channels 4 in addition to the existing Inputs and designated 1 through A4 Contact Configuration 4 pole 2 current
159. e units 3a On the DRC 91C enable Reference Junction Compensation by closing 1 Switch 3 of the appropriate SENSOR ID on the rear of the instrument Hold the LOCAL key and verify the display as 9305 See Section 9305 7 2 3b the DRC 93C enable Reference Junction Compensation by using the SENSOR SCAN and Or keys The Display should show 9305 when the SENSOR key is pressed See Section 9305 7 3 4 Adjust the Offset Adjustment trimpot so that the Display reads the Reference Temperature Note The Offset Adjustment compensates for the thermocouple used in the calibration If another thermocouple is attached or the thermocouple has aged or the configuration of the system is changed then the Offset Adjustment must be repeated 9305 7 6 Curve Data Format The 9305 Thermocouple Input Card will operate with a user defined curve as well as the Internal Curves listed in Table 9305 4 Temperature is calculated by linear interpolation between curve points 9305 7 9305 Thermocouple Input Card The card is hardware limited to reading input between 15 millivolts and 15 millivolts All curves should be limited in temperature so not to exceed these voltage values If Reference Junction Compensation is desired the thermocouple curve must normalized to zero degrees Celcius Compensation also limits the practical range of the card by approximately the room temperature voltage of the thermocouple
160. eady CD asserted by the Interface whenever the DRC 91C 93C 8223 power is to indicate that the Interface is ready to receive and transmit data 8223 2 host tParity Bit optional 8223 3 Switches Configuration of Dip 8223 3 1 Selection of Baud Rate The Model 8223 has a field selectable baud rate using DIP switch package S1 8 switches on the Interface card The baud rate is selected by closing the switch position for the desired baud rate and making sure all other positions are open Table 8223 3 gives the baud rate selection table Only the 300 and 1200 baud rates have been tested and are fully supported Table 8223 3 Baud Rate Switch 51 Baud Rate Switch S1 1234567 8 ececorcs eceorocs OH 8223 3 2 Word Structure Selection The word structure is determined by switch settings for character length parity and stop bits using DIP switch package 52 the Interface Card 6 switches Refer to Table 8223 4 for settings where is OPEN and 1 is CLOSED COPYRIGHT 12 87 LSCI Model DRC 91C 93C Table 8223 4 Switch S2 Switch S2 12345 6 Word Structure Word Structure Choices Stop Bits Invalid 1 Bit 14 not supported 2 Bits Parity Genertn Chck Even Odd Parity Enable Enable Disable Character Length Bits 5 not supp
161. egister Mask Command are potentially changeable in the Status Register Note that the corresponding bit in the Status Register Mask determines whether its counterpart the Status Register can change The Status Register Mask is shown in Figure 4 2 It consists of 8 bits one bit bit 6 which deter mines whether the DRC 91C is to report via the SRQ line and five bits to determine which Status Reports to make Bit 6 is the SRQ 4 19 Section IV Service Request bit and if set allows the DRC 91C to send out a Service Request on the SRQ 488 line If the SRQ bit is not set off then the DRC 91C is inhibited from producing a Service Request The Status Register can still be read by the BUS CONTROLLER to examine the Status Reports but the BUS CONTROLLER will not be interrupted by the Service Request Five of the other seven bits select which of the five Status Reports to make If one of these five bits is set on the DRC 91C will update the correspond ing Status Report bit in the Status Register Then if the SRQ bit bit 6 of the Status Register Mask is set the DRC 91C will send out a Service Request on the SRQ IEEE 488 line By means of a serial poll enable 5 the BUS CONTROLLER determines that the DRC 91C has sent out a service request and then reads the Status Register Reading the Status Register resets the Status Register to all zeros Executing the Q command also resets the Status Register to all ze
162. endix B for a discussion of Precision Option curves and examples of curves that would be used with the 9210 9210 8 REPLACEABLE PARTS Included in this section is Figure 9210 1 It includes the Model 9210 Diode Input Schematics replaceable parts list and illustrated component layout Refer to the manual for ordering information 9210 3 101 034 101 025 106 142 102 072 105 649 102 074 104 005 102 043 104 001 104 355 104 356 104 099 104 461 104 460 104 051 CAP PP 1 0MF 100V CAP PP 33MF 100V_ CONNECTOR IC TO BP 6 POST LOCKING HEADER TRANSISTOR PNP SIGNAL _ 1 2 POS 4 POLE INTERLOCKING MOSFET P CHANNEL IC OP AMP VOLTAGE REFERENCE 6 95V OPTOCOUPLER IC OPTOCOUPLER P S SHIFT REGISTER A D CONVERTER A D REFERENCE TIMER MPP2X 1 0 100 10 MPP 11 33MFD 2420 09 75 1061 283906 2XMTA7 5 NONE 4UGRP 3165 LM308 LM399H OPO7E 740L6000 74016010 CD4021BCN ICL7104 16CPL ICL8068ACPD 1 7555 de Se 2 e vc d E ieu ee s Lou 7 Bb a c T 5 1 1 1 Rol locu qo oL L E E d S 5 d 45 Model DRC
163. entifying a noise problem This is most easily done by connecting the capacitor across the input to the voltmeter The size of the capacitor needed will depend on the frequency of the noise generally related to the power line frequency of 60 Hz and the dynamic impedance of the diode on the order of a few thousand ohms at a 10 pA operating current A capacitor in the range of 10 to 20 uF should reduce most noise effects to an acceptable level However because the capacitor increases the time constant in the circuit a sluggish response should be expected In switching operations 30 seconds or more may be required for the circuit to stabilize This quick fix is not meant as a substitute for proper measurement techniques but in certain circumstances it may be useful Note added in proof The capacitance values given above are for the elimination of the effects of low frequency noise such as 60 Hz If high frequency noise is a problem an additional capacitor of lower capacitance value may be needed The reason for this is because larger capacitors often have an associated inductance which limits their usefulness as a high frequency shunt A S Grove Physics and Technology of Semiconductor Devices Wiley New York 1967 Chap 6 5 M Sze Physics of Semiconductor Devices Wiley Interscience New York 1969 Chap 4 D A Fraser The Physics of Semiconductor Devices Clarendon Oxford 1983 Aldridge Solid State Electron 17 617 1974
164. ents GWBASIC or BASICA IBM Example The following is the same program written for the National Instruments GPIP PC2 IEEE 488 Card for IBM PCs and Compatibles using Quick Basic 3 0 10 CLEAR 60969 BASIC DECLARATIONS 20 1 60969 This number is different for each computer 30 IBINIT2 IBINIT1 3 40 BLOAD bib m IBINIT1 50 CALL IBINIT1 IBFIND IBTRG IBPCT IBSIC IBLOC IBBNA IBONL IBRSC IBSRE IBRSV IPPAD IBSAD IBIST IBDMA IBEOS IBTMO IBEOT IBRDF IBWRTF 60 CALL IBINT2 IBGTS IBCAC IBWAIT IBPOKE IBWRT IBWRTA IBCMD IBCMDA IBRD IBRDA IBSTOP IBRPP IBRSP IBDIAG IBXTRC IBRDI IBWRTI IBRDIA IBWRTIA IBSTA IBERRZ IBCNT 70 TEMPS 91C 91C is IEEE address label set up in IBCONF 80 CALL IBFIND TEMPS TEMP3 Required command to address 91C 90 5 5 5 255 255 largest transfer allowed by IBM format 100 INPUT B Entered from keyboard while running 110 13 10 Add CR and LF to command 120 CALL 5 Send command to 91C 130 CALL IBRD TEMP AS ENTER from 91C SEE NOTE BELOW 140 PRINT 5 Display received information on screen 150 AS SPACES 255 Clear AS 160 GOTO 110 170 END 180 REM 91C will return the data requested but if the command input 190 REM does not request new information the 91C will give the information 200 REM last requested 4 13 3 National Instruments QUICK BASIC IBM Example IEEE
165. eserved for file manage ment There are 3584 bytes free for the storage of curves If the COPYRIGHT 3 88 LSCI Section IV curve stored has 31 data points it will take up 177 bytes For this length curve up to 20 curves can be stored the unit Refer to Appendix B for additional infor mation on curve entry and how the curves are generated 4 16 5 The XEN N gt Command The command XEN No X XXXXX TIT T either adds a point to or edits the curve provided that this curve 15 present The ter minates the data point input If either the units or temperature information matches one of the data points in the curve the curve data point edited to match the XE data point If the information does not match any of the data points for the curve the unit inserts the point in its proper position in the table 4 16 6 The 2 Command Ihe command XKN4N5 erases all the data associated with curve number and repacks the remaining curves stored within the NOVRAM Standard Curves 00 thru 05 are stored in a Prom and are not erasable by this command 4 16 7 The XAC1C N1N5 and Commands The XA an XB commands allows Table 3 4 which defines the correlation between the Remote Position Sensor Curves for the REMOTE SEN SOR ID Note that this correlation exists for both inputs and normally only one input would select the REMOTE SENSOR ID position data Once this data has been change
166. eter This averaging mode can be deselected by switch 2 of the SENSOR ID dip switch on the back panel for a given input if the customer prefers not to average readings The control set point selection is made via increment and decrement buttons on the front panel The display above the buttons indicates the set point value The set point units may be selected independently from the display sensor units The standard set point temperature can be set to 0 1 degree This temperature is converted to equivalent voltage with a resolu tion of 100 microvolts out of 3 volts full scale The optional High Resolution Set Point expands the set point resolution to 0 01 kelvin above 100K and 0 001 kelvin below 100K the equivalent voltage is expanded to 25 microvolts out of 3 volts full scale in a setability of approximately 0 01 kelvin above 40K and 0 001 kelvin below 28K for the DT 470 series sensors control section of the DRC 91C provides three term temperature control Proportional GAIN integral RESET and derivative RATE are individually tuned via front panel potentiometers The gain reset and rate are in a nominal log per cent COPYRIGHT 1 88 LSCI This results Section I Heater power output of the DRC 91C Temperature Controller is a maximum of 25 watts when a 25 ohm heater is used digital meter on the front panel displays the output as a percentage of output range select ed Thus the user can
167. evious resistor and re enable CAL 4 The display will display the number 160 for approximately 30 seconds then the number 206 for another 30 seconds and when complete 0 will be displayed Disable CAL 4 and continue Current Range 2 Value 60 and Current Range 3 Value 6 Substitute a 100 ohm 9317C or 1K 9318 0 resistor for the previous resistor and enable CAL 3 The display will indicate 260 for approximately 30 seconds then 306 for another 30 seconds and finally a 0 Disable CAL 3 continue Current Range 3 Value 60 and Current Range 4 Value 6 Substitute a 10 ohm 9317 or 100 ohm 9318 resistor for the previous resistor and enable CAL 2 The display will indicate 360 then 406 with each time period being proximately 30 seconds When the 0 appears disable CAL 2 and continue Current Range 4 Value 60 Finally substitute the 1 ohm 93170 or 10 ohm 9318 resistor for the previous resistor and enable the last COPYRIGHT 12 87 LSCI 10 ll 9317C 9318C Input Cards switch CAL 1 The display will indicate 460 for ap proximately 30 seconds and then a 0 indicating that the calibration of the card complete Disable CAL 1 and then CAL 8 Set Point D A Calibration A special set point calibration is required for a DRC 91C or DRC 93C with two 9317 9318 Input Cards or if the 9317C 9318C is the only Input Card Since the set point voltage is related to the set
168. fore removing cover 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off Note from the calibration cover the position of the Input Slot the 9305 will occupy 9305 1 9305 Thermocouple Input Card Model DRC 91C 93C Table 9305 1 Specifications Model 9305 Thermocouple Input Card Input Voltage Range Room Temperature Compensated 10 to 10 millivolts Uncompensated 15 to 15 millivolts ture Range Depends on Thermocouple type Refer to Table 9305 2 Thermocouples Ordered Separately Chromel vs Au 0 03 at Fe Chromel vs Au 0 07 at Fe Chromel vs Constantan E Chromel vs Alumel K and Copper vs Constantan T Thermocouple EMF Tables Curve tables are stored in the controller and accessed through normal curve selection The curves are normalized to zero degrees Celcius and listed in Table 9305 4 Input Resistance Greater than 10 ohms Terminal Block and Room Temperature Compensation secondary sensor is installed in the rear panel mounted Terminal Block to measure the Reference Junction Temperature Compensation can be enabled or disabled Offset Adjustment One point hardware adjustment built into the Terminal Block Electronic Resolution 1 microvolt Electronic Accuracy 3 uV for 10 to 10 millivolts 5 up to the 15 and 15 millivoit full scales Overall Accuracy Depends on conformity of the thermoc
169. ftware that interprets the data tries to match the character input to the possible command inputs and processes the command The error is also transmitted by the interface the next time it is asked for a response The error is transmitted in addition to the Output Statement data output For example if a framing error were detected in a command string transmitted to a DRC 91C 93C as P50W3 the interface might respond with Err12 50 25 20 2 047 CR LF If the error were detected in the transmission of the P the gain change would be ignored if it was in the 50 one or two numerics may have been generated If the error were detected in the the interface may not respond in which COPYRIGHT 12 87 ISCI Model 8223 RS 232C Interface case it would need to see another Output Statement command If the error was in the 3 the interface may or may not have responded with data it may default to WO Although errors rarely occur it is suggested that any commands sent to the 91C 93C echoed back by sending the appropriate output Statement command and inputting the stored parameters Any error that is detected is cleared following the first transmission after the error Table 8223 6 interface Error Codes Error Possible Cause Parity Error may be caused by signal line transients or incorrectly specified parity Overrun Error caused by the main processor not reading the input ch
170. g the locking tab on the Input Card connector and gently pulling on the body of the wiring harness mating connector 4 Plug the new 9210 Input into the A Input Card Slot 5 or the B Input Card Slot 6 with the component side to the left of the unit as viewed from the front Connect the wiring harness mating connector to the 9210 making sure that the wiring harness locking tab is seated over the extended edge of the wiring harness mating connector Verify that the wiring harness is in place correctly by noting that the A or B on the 9210 2 DRC 91C 93c harness mating connector is facing up if it is not review the harness installation again Thread the wiring harness along the rear edge of the unit and slip it into the harness strain relief on the rear panel 2 Install the calibration cover by reversing procedure 2 6 Install the top panel 9210 5 OPERATTON The Model 9210 3 Configuration provides microampere excitation current to the sensor The resulting sensor voltage is digitized by a 16 bit A D converter with a resolution of 50 microvolts and a full scale input voltage of 3 0000 volts 100 microvolts and 6 5535 volts for the 9210 6 configuration The digitized value is converted to a serial data string and transferred to the main microprocessor using Diode the 10 optical isolation The sensor voltage is also buffered transferred to the rear panel MONITORS connector for external
171. ge Mode nmv K 3 0 1 0 5 ls 1 0 0 05 0 1 10 0 0 005 0 01 100 0 0 0005 0 001 9210 9220 1 zv 0 1 millikelvin for the Sensor Sensitivity Resistance Mode 6 1 R dR dT 1 Model DRC 91C 3 8 6 1 Temperature Display Resolu tion Set To change the display resolution from the front panel hold in the DISPLAY SENSOR A or B button or the t scan button for longer than one second The display will read M ES Or Use the 44 or vv keys to move the decimal point the direction of increased or decreased resolution Changing the display resolution fixes the resolution transmitted over the bus as well but does not change the resolution of the system Display resolu tion can also be different for each input card i e A and B Also note that the chosen resolution will only be displayed when ap propriate In other words only five digits can be displayed In the temperature mode the chosen input is displayed in the selected scale K C or F with a maximum display capability of 0 01 degrees above 100 kelvin to 0 001 degrees between 1 and 100 kelvin and in the case of the 8217 resistance card to 0 0001 kelvin 0 1 millikelvin below 1 kelvin Please note that this is display capability and neither system resolution nor SYSTEM RESOLUTION VERSUS SENSOR SENSITIVITY Maximum Temperature Resolution in K 9317C 9318C 9220 P2 P3 R
172. gnl Dtctr Data Terminal Rdy The RS 232C signals are used in the following manner Protective Ground AA conductor is taken to case ground potential and is common with the signal ground AB Transmitted Data BA transmits data using the EIA voltage levels 12V and 5V Received Data BB accepts data using EIA voltage levels 8223 1 Model 8223 RS 232C Interface Figure 8223 2 Model DRC 91C 93C Word Structure iStop Bit s Start Bit Character 7 Bits Request to Send CA indicates to the host computer or terminal that the DRC 91C 93C Interface is ready to transmit data The Interface transmits data on line BA when the ON state is maintained on CC CB and CF while a low level on these lines inhibits transmission by the Interface Clear to Send CB indicates to the Interface that Gata transmission is allowed Internally pulled up to maintain ON state when left disconnected Data Set Ready CC indicates to the Interface the computer or terminal is not in a test mode and that power is ON Signal Ground AB this line is the common signal connection for the Interface Received Line Signal Detector CF this line is held positive ON when the Interface is receiving signals from the host computer When held low OFF the BB line is clamped to inhibit data reception Internally pulled up to maintain ON state when left disconnected Data Terminal R
173. hannel to be skipped If all dwell times are zero the instrument stays on the channel selected The DRC 91C gives a direct reading in temperature when used with any DT 470 Series Temperature Sensor All DT 470 Sensors follow the same temperature response curve Four bands of tracking accuracy available Refer to DT 470 technical data for details Diode sensor voltages are digitized to a resolution of 100 microvolts with full scale dependent on input card configuration The tempera ture display has resolution capability of 0 01 kelvin above 100 kelvin and 0 001 kelvin below 100 kelvin For greater precision individual sensor calibrations can be accommo dated with the 8001 Precision Calibration Option which programs the instrument with calibration data for a specific Sensor The algorithm within the instrument l 1 Section I interpolates between data points to an interpolation accuracy which exceeds 0 01K over the entire temperature range of the Precision Option The 16 bit analog to digital converter is accurate to plus or minus the least significant bit which for the 470 series sensor results in an uncertainty of imK below 28K and 45mK above 40K with a transitional region between these two temperatures Therefore temperatures below 28K the overall system accuracy the sum of the instrument accuracy 11mK and that of the calibration itself Lake Shore calibrations
174. he unit Remove the three top panel screws and slide the panel off Note on the calibration cover the position of Option Slot 2 which the 8223 will occupy 3 Remove the four screws that secure the calibration cover to its clips and remove tbe cover Remove the two back panel mounting clips that secure the J10 blank cover plate to the interface opening and remove the plate 8223 3 Model 8223 RS 232C Interface 4 Remove the red jumper JMP6 on the Microprocessor Board This is the jumper closest to the front edge of the microprocessor card 5 Plug the internal interface cable into the 8223 printed circuit board PCB with the locking tab configured properly Plug the 8223 PCB into Option Slot 2 with the component side to the left of the unit as viewed from the front Gently thread the RS 232C internal cable along the inside edge of the rear panel so that it will not interfere with the installation of the calibration cover or top cover 6 Position the 25 pin RS 232C Interface connector in the J10 opening the back panel secure it in place using the screws provided 7 Install the calibration cover by reversing procedure 3 8 Install the top panel 8223 6 OPERATION The 8223 RS 232C Interface has a 256 character FIFO buffer for input commands The interface accepts commands the same as for the IEEE 488 Interface until it sees the End of Line EOL sequence The 8223 requires carriage return li
175. he A input or the B input of the DRC 91C If the remote position is non zero then the correlation table of Table 3 4 column 1 is valid for positions 01 through 30 The differences from the SENSOR ID s is that the position can be changed remotely and 30 positions rather than 16 are available for one but not both of the inputs Note that AOO or BOO is available over the REMOTE SENSOR ID if the SENSOR ID switch is set at 10000 The DRC 91C is shipped from the factory with curve 02 stored in all positions of this table Caution Do not set both SENSOR ID switch 4 s to 1 since only one input should be tied to the REMOTE SENSOR ID and its position Section III 3 10 4 Addition of 8229 Scanner Option Adding the 8229 Scanner to Input A with Switch 4 closed 1 overrides the correlation Table for that input and switches 5678 of the A SENSOR ID scanner Inputs AO through A4 now correspond to posi tions A00 through A04 which indicated in Bold letters in Table 3 4 Consequentiy different curves can be assigned to each of the five scanner inputs if desired 3 10 5 Display of Accessed Position and Assigned Curve By holding in the IOCAL key for more than one second the Display and the Heater windows will have the following format Display Heater 07 OO 09 20 3 For the input chosen switches 45678 are set as 10111 selecting position 7 the curve selected is curve 09 Either that curve does not exist or i
176. he TAIK listed and LISTEN address COPYRIGHT 3 88 LSCI Model DRC 91C 4 4 3 The IEEE 488 INTERFACE bus address for the DRC 91C is set by Switches 4 through 8 which are reserved for the address selection Switch 4 is the most significant bit MSB 216 and 8 is the least signi ficant bit LSB 1 The factory preset address of this instrument is 12 see Table 4 2 Address switch numbers 5 and 6 should be CIOSED 1 which will result in the Address Switch having a setting of 00001100 or 10001100 dependent on the requirements for the delimiters 4 5 488 BUS COMMANDS 4 5 1 A Uniline Command A Uniline Command Message is a command which results in a single signal line being asserted The DRC 91C recognizes two of these messages from the BUS CONTROLLER REN and IFC See Table 4 3 When the BUS CONTROLLER executes the ap propriate software code the effect is to pull the corresponding Inter face Management line low For example when the software command REMOTE712 is executed by the 86 digital computer the management line REN is pulled low and the listen address 12 issued to signal the instrument having address 12 DRC 91C to go into the remote mode The SRQ is a uniline command asserted by the DRC 91C when it wishes to signal the BUS CONTROLLER The BUS CONTROLLER will in turn use the Addressed command SPE Serial Poll Enable described below to inter rogate the DRC 91C about the reason or reas
177. he unit 5 6 1 Input Card Calibration Calibrate each input card as speci fied in Section VI for that card 5 5 Section V 5 6 2 Set Point Voltage Calibration Calibrate the Set Point Voltage as follows 1 Remove the instrument cover 2 Calibrate with the Control Switch selecting either a 9210 or 9220 Input Card and the 3 configuration If the DRC 93C does not contain one of these input cards calibrate the set point by following the procedure described with that Input Card 3 To calibrate the Set Point voit age with a 9210 or 9220 card connect the LO lead of your DVM to and the HI lead to TP25 SP V 4 Enter a set point of 0 0000V and adjust the potentiometer labeled SP ZERO ADJ until the DVM reads 0 0000 volts 5 Enter a set point of 2 7000V and adjust the potentiometer labeled SP SPAN ADJ until the DVM reads 2 7000 volts 6 Repeat the two settings until the values are constant 5 6 4 Calibration of Power Output If the heater output is not the standard 25 watts for the DRC 91C the optional power output installed should be indicated on the front page of this manual 1 Use a load resistor between 10 and 25 ohms with a wattage rat ing equivalent to its resis tance The W60 output requires a 25 ohm load with a wattage rated 1 5 times the resistance value Set a set point and gain value which results in full scale output 5 6 Model DRC 91c on the MAX Heater Range scale 2 W
178. hermal time constants encountered at low temperatures Secondly some controllers such as the DRC 82C have a manually adjustable power output control This control can be used in either of two modes 1 open loop with a manual adjust of heater power in place of the signal from the deviation amplifier and 2 automatic where the adjustment is in addition to the controller s closed loop signal Mode 1 is extremely helpful in set up procedures and in subsequently determining the power levels associated with the desired temperatures In Mode 2 one can reduce and sometimes eliminate temperature offset by providing the required power without the need for a large error signal to drive the output stage This latter method has a name manual reset and serves as an introduction to the next section on reset control IV PROPORTIONAL GAIN PLUS INTEGRAL RESET TEMPERATURE CONTROL The manual reset adjustment described above varies markedly with the temperature set point and with the often changing heater power demands of the system Thus it is normally neither convenient nor desirable to have to resort to such a means of eliminating temperature droop offset Instead suppose a circuit could be added to the loop that would 1 sense that there is a steady state offset signal within the proportional band 2 make a bit by bit addition to the power output proportional to the magnitude of the offset and 3 continue the corrective action until the offset i
179. hich makes it extremely easy to determine one wire from another 2 3 7 J3 Sensor Output MONITORS Buffered voltage outputs for both Sensor Input A and B are available on the J3 connector on the back panel of the instrument The volt age from the Model 38225 Analog Output Option is present on this connector also The connector pin assignments are given in Table 2 3 Table 2 3 J3 MONITORS Connections 7 A verag output Output Input A Voltage Output Input B 10 mV K Analog Output Ground for Analog Output Setpoint Output Ground A B Setpoint Optional Shield 2 3 8 SENSOR ID Switches The SENSOR ID and B SENSOR ID switches determine slope for a 9215 capacitance input card if present activate or deactivate digital filtering and enables thermal aver aging on the 9317C or 9318C resis tance input card when present or ice point compensation when a 9305 thermocouple input card is present Switch 4 determines whether Switches 5 8 select a stored curve directly or a curve via the posi tion correlation table 1 table of position versus curve num ber for non thermocouple inputs Switches 5 8 define the thermo couple type when 9305 thermo couple input card is present The switch information is described in Figure 2 3 Section II Table 2 4 indicates the position of the address switches to select standard curves stored within the instrument Information on Pre cisio
180. icroamperes Range 1 1 to 10 microamperes Range 2 10 to 100 microamperes Range 3 and 100 to 1000 microamp COPYRIGHT 12 87 LSCI 9317C 9318C Input Cards eres Range 4 Each range has 64 independent current values The ranges overlap each other for example Range 1 Value 60 is equivalent to Range 2 Value 6 so that a smooth transition from range to range can be made The current value as well as direction is controlled by a 16 bit bipolar D A converter Jhis current resolution is required to maintain as close to 1 05 9317 or 10 5 9318 millivolts across the sensor possible on card microproces sor stores calibration constants for each of the four ranges at the end point values of 6 and 60 for both the positive and negative directions a total of 16 current calibration constants in all The resulting sensor voltage is converted from a differential to single ended signal and amplified by a factor of 1000 9317C or 100 93180 amplified signal is digitized microprocessor controlled 15 bit A D converter The microprocessor also has calibration constants stored for the gain and offset of the input amplifier As a result of the A D resolution and calibration constant manipulation of the sensor signal the sensor signal can be digitized with a resolution of 1 part in 10 000 over most of the resistance range the 9317 9318 covers There is also sample and hold net
181. ided by the load s Resistance If the next lower range 1 is COPYRIGHT 3 88 80 to 1 00 the reading will Section V selected then the heater will put 0 33 amperes through the resistor 100 percent 2 range will output 0 10 at full scale output At the 3 range the output will be 0 033 fuli scale and at the 4 range the output will be 0 001 amperes 5 5 8 2 W60 Watt Option If the unit has a W60 output option the Max scale has a 1 55 amp 40 volt limit If a 25 ohm resistor is used the controller will supply 60 watts to the load If a 100 ohm resistor is used on the Max scale the unit will output 40 volts at 0 4 amps or 16 watts lower ranges are scaled as explained in 5 5 7 1 above except the voltage limit is 44 volts NOTE The values given above are nominal values If they are slight ly off it should not effect opera tion since the heater circuit is part of a feedback loop 5 6 CALIBRATION The adjustments and test points referred to in this section are la beled on the instrument calibration cover Remove the two top panel screws and slide the top cover off to gain access to the adjustments and test points Note The unit should be allowed a one hour warm up time to achieve rated specifications This cali bration procedure is for a DRC 91C with standard diode A and B inputs For other configurations refer to Section VI for the specific Input Card present in t
182. if in the lower Display press the key while still holding down the SCAN key 4 Release the key or and then the SCAN key key You should press the SENSOR key to verify that the sign is as desired 9305 7 4 Selection of Reference Junction Compensation via the Computer Interface To select or prevent Reference Junction Compensation via the IEEE interface use the 1 and commands described in the DRC 91C Section 4 8 5 or DRC 93C Section 4 8 9 Instruction Manual The Reference Junction Compensation bit may be listed as Switch 3 or the Thermal Correction bit used on the 9318C card Turning on 1 that position turns on the compensation 9305 7 5 Rear Panel Offset Adjustment When a new or different thermocouple 15 attached to the instrument it is desireable to permit the addition of an offset to compensate for discrepancies in the thermocouple material leads and connections Offset Adjustment trimpot is provided next to the Terminal Block on the Back Panel to allow quick calibration of the thermocouple without removal of the instrument cover COPYRIGHT 6 88 LSCI 9305 Thermocouple Input Card The procedure is as follows 1 Place the thermocouple in a reference bath of known temperature liquid nitrogen ice etc Allow the system to stabilize to the Reference Temperature 2 With the front panel of the instrument select the thermocouple input and the desired temperatur
183. ified by the controller for a high enough amplifier gain setting the output of the controller will become unstable and oscillate In addition the placement of the sensor with respect to the heater and the sensor construction and mounting itself introduce thermal lags This is due to the finite thermal conductivity of the block and the thermal resistances between the heater sensor and the block These thermal lags introduce a phase shift between the controller output and the sensor which will reduce even further the gain at which the system will be stable Therefore the thermal block design is extremely important in the proper performance of any cryogenic system No controller can make up for poor thermal design of the system nor can good design overcome the inherent limiting properties of the materials and sensor packages which are currently available Application Notes 3 Lake Shore Cryotronics Inc Since the thermal conductivity of cryogenic materials is finite good practice dictates that the controller power output be the same order of magnitude as the cooling power If for example the cooling power is 0 2 watt and 50 watts is available a change in set point to a higher temperature outside the proportional band of the controller will dump 50 watts into the system block Due to the thermal lag of the block etc a large temperature overshoot may occur with the system stabilizing only after several oscillations This thermal lag can easily
184. ighting 0 0 1 0 1 0 0 1 0 1 0 1 0 1 Bit Choices SRQ Bit lt Display Data Overload Error 4 Indicator Display Sensor Channel Change Table 4 14 Commands to Fix the Status Register Mask Overload Not Display Control 1 Display Error Used Channel Data Data QC Not SRQ Used Bit Indicator Change Limit Ready Ready 2 2 2 4 jr 1 on on on on on n on on on on on Note On means 1 Those entries left blank are OFF 0 2 4 22 COPYRIGHT 3 88 LSCI Model DRC 91C 4 11 4 The Data String This command gives the Status Register Mask and control channel limit information 4 12 COMMAND OPERATIONS The following example in HP Basic sets the set point to 123 4 K the gain to 45 the reset integral to 30 the rate derivative to 25 the heater range to 107 and the output statement to be 1 OUTPUT 712 S123 4P45130D25RAW 1 L pata 12 91C preset address 7 IEEE card address Output Data Command If the user were to monitor the IEEE 488 Bus when the computer sent its command string over the Bus the following IEEE 488 Format would b
185. ilicon diode temperature sensor operating at 4 2 K The symbols represent data recorded at three different dc operating currents with a 60 Hz signal superimposed Equivalent temperature errors are indicated along the right edge Application Notes Lake Shore Cryotronics Inc The utilization of the small signal model has the advantage of being analytically simple However the model does not contain the nonlinearity inherent in the forward biased IV characteristics of a p n junction In an attempt to retain the non linear characteristics V lac lac was expanded in a Fourier series The first term constant term is just the average dc voltage in Eq 3 and is not seen by the voltmeter operating in an ac measurement mode The remaining terms in the Fourier series can then be used to calculate the rms voltage which will be read by the voltmeter 2 B ME S a cosnat b umor dt 7 where and bm are the Fourier coefficients In order to evaluate the Fourier coefficients V I was expanded in a power series around lac Sufficient terms were maintained in both the power series expansion and in Eq 7 to give a second order correction to Eq 5 1 5 12 Vis E 8 2 dc lac I Substitution of this result into Eq 4 gives the 77 K offset voltages shown in Fig 4 by the dashed line Slightly better agreement with the experimental data is seen at the higher rms voltages At 305 K the t
186. ilohms for 9220 3 or 100 ohms for 9220 2 and 9220 1 with a tolerance of 0 01 or better 3 Precision Voltage Source capable of supplying a voltage with an accuracy and resolution of 10 microvolts out of 1 volt or better The unit should be allowed a one hour warm up time to achieve rated specifications Refer to the 9210 section for the calibration procedure for the 9220 3 and 9220 6 configurations Use the following procedure to calibrate the 9220 P2 P3 and R1 Configurations 1 Remove the three top panel screws and slide the panel off 2 Set 100 1 Current Connect the appropriate precision resistor across the A I and B I pins of the five Pin input connector for the input 21 or J2 the 9220 occupies Connect the DVM plus lead to the I pin and the minus lead to the I pin Adjust the trimpot marked 1mA for P2 on the for P3 for R1 for the appropriate Input Card until the voltage across the resistor is equal to the sensor current times the resistance the tolerance of the resistor 3 Calibrate the Input 10 Amplifier Connect the DVM plus and minus leads to the V and V Sensor Output Signal pins for the appropriate Input Card of the 73 MONITORS connector Connect the precision voltage source across the and D V of 21 INPUT or J2 INPUT B COPYRIGHT 12 87 LSCI calibration cover 100 9220 Input Card for the appropriate inp
187. ing the Time has a destabilizing influence It should therefore be normal practice io FIGURE 6 The effect of adding Rate to the contro circuit to dynamically widen the proportional band and turn off the rate control when near the control point reduce the overshoot which would occur in its absence 150secs The differentiator circuit should precede the reset integrator in the circuit so that the deviation and derivative signals acting on the integrator input will be just sufficient to create the proper reset value by the time the temperature reaches set point In some cases it is important for the rate circuit to precede the deviation amplifier as well i e immediately following the sensor input This would then prevent the rate circuit from operating on changes in the set point such as in temperature seep applications Fortunately most sweeping is done slowly enough so as to be unaffected by typical rate time constants To determine the rate control setting in seconds for a system an abrupt increase in power is applied to the system while in equilibrium The time delay is then observed to the start of the resulting temperature increase as indicated by the control sensor This delay corresponds to the value to be set on the rate control Application Notes 5 Lake Shore Cryotronics Inc VI SENSOR CONSIDERATIONS Sensor Gain Revisited Since a controller will amplify input noise as well as sensor signal it becomes im
188. is thermocouple has the highest sensitivity of the three ASTM standard thermocouple types typically used for low temperature applications types E K and T The E thermocouple is the best choice for temperatures down to about 40 K It is recommended for use in oxidizing environments or in sulphurous reducing atmospheres It should not be used in environments that promote corrosion 9305 5 3 Type K Thermocouples The ASTM designation type indicates a thermocouple pair consisting of Ni Cr alloy Chromel as the positive thermoelement KP a 1 1 alloy Alumel as the negative thermoelement It should not be used in sulphurous or reducing environments that promote corrosion 9305 5 4 Type T Thermocouples The ASTM designation type T indicates a thermocouple pair consisting of Cu Copper as the positive thermoelement TP and a Cu Ni alloy Constantan as the negative thermoelement TN This type of thermocouple may be used in vacuum as well oxidizing or reducing environments down to about 90 K At temperatures below 80 K the thermoeietric properties of the positive thermoelement very dependent on the impurity of iron 9305 6 PRINCIPLE OF OPERATION The 9305 Thermocouple Input Card has the capability of interfacing 5 different thermocouple types COPYRIGHT 6 88 LSCI Model DRC 91C 93C Table 9305 2 to the Lake Shore DRC 91C and DRC 93C Temperature Controllers
189. ital Computer which tells the DRC 91C which functions to perform COPYRIGHT 3 88 LSCI Section IV V OPERA TION The interface works on a party line basis with all devices on the bus connected 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 The following discussion of the Signal lines on the bus are for general information Your digital computer handles these lines through its circuitry and software The user need never concern himself with these lines or signals however knowledge of their purpose will help one to understand the operation of the Interface There are 16 signal lines contained on the bus 1 8 Data Lines 2 3 Transfer Control Lines 3 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 three Transfer Control lines and the five Interface Management lines are asserted low which means that they carry out their function when pulled low When the voltage on one of these lines is high then the line is not asserted and the function is inhibited The General Interface Management Lines IFC Interface Clear ATN Attention REN Re
190. ith full power across the load resistor on the 1 scale place the DVM LO probe in TP19 PWR V and the DVM HI probe in TP21 and adjust PWR V until the DVM reads 1 000 volts There now should be one ampere through the load 1 5 amperes in the case of the W60 The heater can now be turned off 3 Place the DVM IO into TP15 PWR V and the DVM HI into TP17 HTR V and adjust PWR V ADJ until the DVM reads 1 0000 volts 4 Place the DVM IO into TP20 PWR LO and the DVM HI into TP16 VREF and adjust PWR VREF until the DVM reads 1 0000 volts 5 Repeat 3 and 4 until they do not change Note TP 24 CNT V is the control voltage For the 9210 20 3 it is the voltage across the sensor for the 9210 20 6 it is 0 458 times the voltage across the sensor TP 25 is the set point voltage and is of opposite sign from TP 24 These two voltages algebraically sum to the error signal 5 7 TROUBLESHOOTING Information on troubleshooting the Model DRC 91C controller is con tained in this Section 5 7 1 Sensor Current If the sensor current is not within specifications Section 5 5 3 then adjust the current trimpot on the input card Section VI COPYRIGHT 3 88 LSCI Model DRC 91C 5 7 1 Monitor Voltage Display Voltage or Resistance The display reading in volts or resistance should match the monitor reading and the voltage across the sensor except for the 9215 9305 9317C and 9318C input cards and the 6 configuration If the readi
191. k Bits 0 and 1 Display and Control Data Ready Enables 4 20 4 11 3 2 Status Register Mask Bit 2 The Control Channel Limit Enable 4 20 4 11 3 3 Status Register Mask Bit 3 Display Sensor Channel Change Enable 4 20 4 11 3 4 Status Register Mask Bit 5 Overload Error Indicator Enable 4 20 4 11 3 5 Examples for setting Mask 4 21 4 11 3 6 Status Register Mask at Power up 4 21 4 11 4 The Data String 4 23 4 12 Command Operations 4 23 4 12 1 Output Data Statemants 4 23 4 12 2 The WO Data String 4 23 4 13 Sample Programming e 4 24 4 13 1 HP86B Keyboard Interactive Program Ew ae 4 24 4 13 2 National Instruments IBM Example s 4 25 4 13 3 National Instruments QUICK BASIC IBM Example 4 25 4 13 4 HP86B Bus Commands Program e gt 4 26 4 14 SENSOR CURVE PROGRAMMING INSTRUCTIONS 4 27 4 14 1 The Command E Iw dA TE 4 27 4 14 2 1 2 Command e d 4 27 4 14 3 The XDA Command E 4 30 4 14 4 XCNQ N5 Command de si 4 30 4 14 5 Command m 24721 4 14 6 XKN N5 Command 4 4 31 4 14 7 The XAC4Co5 N4N5 and N1N5 Commands
192. kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkhk kk ee dede he fe dece dede eee Set Point Data Request Output of Instrument Data nt D Lu N11N12N13 N14N15 8 Characters plus up to 2 terminators where the 11 15 variations are the same as for WO see Table 4 15 COPYRIGHT 3 88 LSCI Model DRC 91C 4 9 3 Setting the GAIN Proportional The P Command The gain is a multiplier between 0 1 and 99 a range of 990 i e 99 0 1 990 A gain of 0 0 is not allowed The format is free field with examples of the command being P 1 0 1 P9 9 9 0 99 99 etc Section IV The string P987 12 will be inter preted as P87 i e the first valid combination tied to the decimal point or end of string will be retained A P transmitted by itself is equivalent to PO or 0 and sets the gain to 0 1 When returning to LOCAL the gain setting if changed over the IEEE 488 Bus is no longer valid since the 91C will now read the front panel gain potentiometer setting Table 4 10 DRC 91C Command Request Summary for the Control Parameters Command Functional Description PN4 N 5 PN 1 2 1 N gt or DN 112 RN4 Setting of all other Control Parameters Proportional GAIN is 0 1 through 99 Examples the command are P PO 0 0 and P99 Integral RESET is 0 0 OFF through 99 three characters including the decimal point Forms of the com
193. l to but opposite in polarity to the set point signal and the error signal will be zero In older instruments the set point is normally calibrated in millivolts or volts or resistance corresponding to the sensor output signal Most modern controllers have stored within them the appropriate voltage temperature or resistance temperature sensor characteristic so that the set point can be calibrated directly in temperature However as discussed in Section VII this convenience feature can compromise the resolution and accuracy of the controller The output of the controller is dc power to a resistive heater the output magnitude of which depends on the size and sign of the error signal as well as on the gain of the deviation amplifier and the output power supply Since the controller s power output state tracks the deviation amplifier output it is evident that the power output is proportional to the magnitude of the error signal In process control nomenclature this response is described in terms of proportional control Let us examine the behavior of the sensor signal set point deviation circuit in a modern cryogenic controller the Lake Shore Cryotronics Model DRC 82C In figure 2 the amplifier output deviation gain times error is plotted against the error signal for two amplifier gains A 100 and A 1000 Gain in this closed loop system refers not to the power gain as in an audio amplifier but is related to the maximum
194. l so that it won t interfere with the installation of the calibration cover or top cover NOTE Be sure that the card is centered in the slot The harness will have a tendency to push the card forward and may some instances cause the card instrument to not behave properly 9215 4 DRC 91C 93C 5 Position the 9215 connector plate in the appropriate opening and secure it in place using the screws provided 6 Install the calibration cover by reversing procedure 2 7 Select either the 9215 15 9215 150 configuration pressing the appropriate pushbutton switch 8 Install the top panel 9215 5 SENSOR CONNECTIONS The 9215 connector plate supplies two independent dual isolated connectors for the sensor connec tions four lead measurement is used to minimize the effect of series resistance on the capaci tance measurement Since the capacitance sensor is non polariz ed one pair should be used for the current connections and the other pair for the voltage connections The pin contact of the connector is and the socket 9215 6 SELECTION OF THE SIGN OF THE TEMPERATURE COEFFICIENT The temperature coefficient of some Capacitance Sensors can be positive or negative depending the temperature range The 9215 Card produces a voitage proportional to the Capacitance which is sent to the control circuitry of the DRC 91C 93C to be compared to a user selected setpoint For control to
195. l time proportioning ON OFF basis This often introduces noise within the system which may interfere with the cryogenic experiment An advantage that the microprocessor and its read only memory provides for users of digital controllers is that of a direct reading in temperature set point and sensor readout However as noted in Section Ill this feature may exact a price In the real world there is always an error due to lack of perfect conformity between the true sensor voltage or resistance temperature characteristic and the value actually stored in memory This error will depend on the degree of non linearity of the characteristic and on the amount of storage available It is seldom cost effective to keep the conformity error as small as the useful resolution of the controller system Thus in the 14 bit system referred to earlier in this section its 4 mK resolution would be swamped by e g a conformity limited 100 mK Fortunately in a controller such as the DRC 82C the user can select either a temperature or voltage resistance set point and readout The choice between analog and digital controllers turns out to be not a choice at all but an optimum combination of the best features of each True analog control provides a heater output that is a continuous function of the sensor signal and so eliminates the sampled data problem This analog control may be combined with digital circuitry for readout of sensors and power output for setting th
196. lable to the user of this instrument Lake Shore Cryotronics Inc offers a calibration service Contact a factory representative for information concerning calibration NOTE Setpoint calibration is described in Chapter 5 of the DRC 91C and DRC 93C Instruction manual The only additional instructions required when calibrating the setpoint D A converter with the 9305 card is to make sure that the Reference Junction Compensation is turned off Section 9305 7 3 9305 9 CALIBRATION The controller should be allowed a one hour warm up time to achieve rated specifications Use the following procedure to begin calibration of the 9305 Thermocouple Input Card 1 Remove the three top panel screws and slide the panel off 2 Configure the controller so the card to be calibrated is the CONTROL input 3 Locate the DIP switch S1 on the 9305 Input Card Open 0 S1 1 for calibration This forces the 9305 to update Secondary Sensor information every conversion Cycle Under normal operation 51 1 closed 1 COPYRIGHT 6 88 LSCI Model DRC 91C 93C The Secondary Sensor information is updated once every 25 cycles Locate the current Secondary Sensor sensing resistor terminals I and the Secondary current source adjustment 104A the Control Amplifier Span adjustment CNT V and the A D converter span adjustment A D on the calibration cover for the 9305 Card Locate the Rear Panel Offset Adjustment
197. lacement or repaired parts will be warranted for only the unexpired portion of the original warranty All products are thoroughly tested and calibrated to published specifications prior to shipment Calibration Certifications are offered for six month periods only Where such documentation must be updated re certification service is offered by Lake Shore Cryotronics Inc at a reasonable cost LIMITATION OF WARRANTY This warranty does not apply to defects resulting from improper or inadequate maintenance unauthorized modification or misuse operation outside of the environmental specifications for any product or part or buyer supplied software or interfacing THIS WARRANTY IS IN LIEU OF ANY OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE WHICH ARE EXPRESSLY EXCLUDED THE OWNER AGREES THAT LAKE SHORE S LIABILITY WITH RESPECT TO THIS PRODUCT SHALL BE SET FORTH IN THIS WARRANTY AND INCIDENTAL OR CONSEQUENTIAL DAMAGES ARE EXPRESSLY EXCLUDED CERTIFICATION bake Shore Cryotronics Inc certifies that this product has been inspected and tested in accordance with its published specifications and that this product met its published specifications at the time of shipment The accuracy and calibration of this product at the time of shipment are traceable to the United States National Bureau of Standards Copyright 12 87 TABLE CONTE SECTION I GENERAL INFORMATION
198. ling which could fracture a solder joint or lead if installed under tension at room temperature The DT 470 sensor is designed for easy removal for recalibration checks or replacement and the following discussions for each of the adapters are geared in this direction If semi permanent mountings are desired the use of Stycast epoxy can replace the use of Apieson N Grease In all cases the mounting of the sensor should be periodically inspected to verify that good thermal contact to the mounting surface is maintained 10 Application Notes Lake Shore Cryotronics Inc DT 470 SD The SD version is the basic package for the DT 470 sensor line from which all 2 16 mm other configurations are made using the appropriate adapter The base of the 0 98 mm X 1 4 mm device has a gold metallized surface and is the largest flat surface on the Anode sensor The base is electrically isolated from the sensing element and leads 1 84 mm and all thermal contact to the sensor must be made through the base A thin braze joint around the sides of the SD package is electrically connected to the gt Cathode sensing element Contact to the sides with any electrically conductive material 3mm must be avoided When viewed with the base down and with leads towards the observer the positive lead anode is on the right For a removable mount the Sd sensor can be3 held against the mounting surface with the CO adapter see below or similar clamping mecha
199. mand are IO 10 0 through 199 Derivative RATE 1 2 is 0 0 OFF through 99 three characters including the decimal point Forms of the command are DO 00 0 through 099 Heater Range is 0 through 5 Forms of the command are RO through R5 Heater Current 0 0 33 mA 100 mA 330 mA lA dede de dede de hee dede de dee de che de dee dede dee dede he de dee dece ehe ede debe dee de de e de f de x An A Request Functional Description Control Parameters N4N5N4 N4N5Ng Nj3NgNo N49 N41N45N44 17 characters plus up to 2 terminators where N4N3N4 is the Gain Value 5 6 is the Rate Value N7NgNo is the Reset Value N10 is the Heater Range COPYRIGHT 3 88 LSCI N11N12N13 the 3 of Heater Power or Current out Section IV 4 9 4 Setting the RESET Integral I Command The reset is set from 0 1 through 99 1 to 990 seconds Like the gain command it is free field with the same characteristics and format It will also revert back to front panel settings under LOCAL control A setting of 0 0 turns the reset off 4 9 5 Setting the RATE Derivative D Command The rate is also set in seconds 10 0 1 to 99 0 0 off It handles its input format exactly the same as both gain and reset commands as well as the transition to front panel control from REMOTE 4 9 6 Heater Range The R Command heater range be changed over the bus with the RN command Rl or and up are e
200. mation The and BC4C Commands Ihe purpose of this command is to select Filtering of the A and B input whether the Remote Position Data is used to establish the curve numbers the Temperature Coefficient sign for the 9215 card and whether or not the thermal correction is desired on the 9317C 9318C cards The information for these commands is sent to the DRC 91C to set the functional parameters as described in Table 4 7 Table 4 7 defines the and 1 2 definitions as independent functions If multiple functions are to be selected the character equivalents are additive see examples below which are given as SENSOR A ID s they pertain to SENSOR B ID s as well A20 Select Sensor 02 to be used to determine temperature A22 Enable digital filtering and select Sensor Curve 02 to be used to determine temperature 28 Enables the REMOTE SENSOR ID If the remote position data is 0 then the sensor curve reverts to the curve in 00 or BOO rather than being selected from the REMOTE SENSOR ID Table 2 Enable digital filtering in addition to the A28 description 4 8 6 The SENSOR ID on Return to Local When the DRC 91C is returned to local the SENSOR ID s on the back panel are read and data entered over the IEEE 488 Bus using the commands Or 1 is lost Section IV Model DRC 91C Table 4 7 DRC 91C Command Summary for Instrument Setup Functional Descriptio
201. mote Enable EOI End or Identify and the 580 Service request manage the bus and control 4 1 Section IV the orderly flow of commands on the bus The IFC ATN and REN manage ment lines are issued only by the BUS CONTROLLER The IFC Interface Clear management line is pulled low by the BUS CONTROLLER to clear the interface The ATN Attention line is the management line used by the BUS CONTROLLER to get the attention of the devices on the bus The BUS CONTROLLER does this by pulling the ATN line low and sending talk or listen addresses on the DATA lines When the line is low all devices listen to the DATA lines When the ATN line goes high then the devices addressed to send or receive data for example the DRC 91C perform their functions while all others ignore the DATA lines The REN Remote Enable management line is pulled low by the BUS CONTROLLER to enable a device the DRC 91C to perform the functions of TALKER or LISTENER The EOI End or Identify management line is pulled low by the BUS CONTROLLER or TALKER the DRC 91C to indicate the end of a multiple byte transfer sequence Also the EOI line along with the ATN line are pulled low by the BUS CONTROLLER to execute a polling sequence The SRO Service Request management line is pulled low by a device for example the DRC 91C to signal the BUS CONTROLLER that a process is completed a limit overload or error encountered In some c
202. mum heater current of one amp ere squared times the heater resis tance times the range setting The DRC 91C Temperature Controller is shipped from the f actory with the front panel meter indicating power If the user prefers he can change this to a current meter by turning on switch 6 of S7 the eight sta tion dip switch located at the rear center of the main board COPYRIGHT 12 87 LSCI Section III 3 11 6 The HEATER POWER RANGE set ting is determined by the Push Buttons directly below the HEATER POWER display MAX corresponds to a 100 or 1 multiplier while 1 2 and 3 corresponds to a 10 1 1072 and 10 gt multiplier respectively The OFF button turns off the output power independent of the set point and the control parameters NOTE The DRC 91C is equipped with a current limit vernier on the rear panel which can iimit the output current on the MAX scale between 0 33 and 1 ampere dependent on setting If your instrument will not deliver full power this ver nier may be set wrong or your load resistance may be too large and you are compliance voltage limited NOTE a range change the DRC 91C ramps the GAIN to 0 and turns OFF the RESET and RATE prior to changing ranges After the range is changed the settings are re turned to what they were prior to the range change This protects the load from seeing the increase or decrease in range power as a step function 3 12 LOCAL REMOTE BLOCK 3 12 1 LOCAL
203. n Selection of Units Sensors Resolution and Deviation FOC Function 0 Select Set Point Control Units Forms of the command are FOK kelvin FOC celsius FOF fahrenheit F1AC4 or 1 1 and FOS for Sensor Units in volts ohms or nanofarads Function 1 Select the A or B Input Units Forms of the command are 1 kelvin celsius F1F fahrenheit and F1S for Sensor Units in volts ohms or nanofarads Function 2 Select Display Sensor bn S A or Input B Forms of the command are F2A0 F2A1 F2A2 F2A3 25 4 and F2SB or F2SBO With 8229 Scanner Card Only F3AN4 Function 3 Select the or B Input Resolution N4 is or XXX 1 xxx x 2 3 XX Xxx or 4 x xxxx F3BN4 Forms of the command are F3AO or F3BO F3A1 or F3B1 etc 1 Input A ID and B ID 1 2 are 00 thru FF Forms of the command are 00 thru AFF C ranges between 0 and F BC1 C3 If is between and 7 then C selects the Sensor Curve number 00 0 thru 15 F If 1s between 8 and then corresponds to a Remote Position between 0 and ERO 2 __ 3 4 4 3 2 1 3 4 56 7 8 4 8 8 4 2 t ft 4 is MSB 1 is LSB Switch Nos on SENSOR ID 1 Binary Weighting Remote Position On Curve Off Bit L Thermal Correction Digital Filtering Thermal Correction or Ice Point Compensation Card Thermal Correction 0
204. n rate reset units and heater power range Provides output of display in units chosen units and all front panel functions except power on off and Display Sensor Selec tion Allows input of curve data for calibrated sensors Dimensions Weight 432mm wide x 102mm high x 330mm deep 17in x 4in x 13in Style L full rack package Net weight 8kg 17 lb Power 90 110 105 125 or 210 250 VAC selected via rear panel with instrument off 50 or 60 Hz 75 watts Accessories connector connector Supplied Mating for sensor monitor instruction manual Model DRC 91C SECTION Section II INSTALLATION 2 1 INTRODUCTION This Section contains information and instructions pertaining to instrument set up Included are inspection procedures power grounding requirements environ mental information bench and rack mounting instructions a descrip tion of interface connections and repackaging instructions 2 2 INITIAL INSPECTION This instrument was electrically mechanically and functionally spected prior to shipment It should be free from mechanical damage and perfect working order upon receipt To confirm this the instrument should be visually inspected for damage and tested electrically to detect any concealed damage upon receipt Be sure to inventory all components supplied before discarding any shipping materials If there is damage to the instrument in tran sit be su
205. n Algorithm developed by Lake Shore The format for the data to be stored using the XCN N gt 5 command as outlined in Section 4 is the same as for a standard curve except the resistance is converted to LOG value where 1000 ohms would look like 4 0000 Refer to APPENDIX B for a definition of the curve requirements The curve data is resistance order The resistance and temperatures for the 9317C 9318C are in ohms up to 100 000 ohms and in kelvin up to 399 9 9317C 9318C 9 REPLACEABLE PARTS Included in this section is Figure 9317C 9318C 1 It includes the Model 9317C 9318C Resistance Input Schematic replaceable parts list and illustrated component layout Refer to the manual for ordering information Switch Definition switch closed Calibration Enable Current Source DAC Zero 9317C 9318C 10mvV 10 10K 100K 1K ohm 100 ohm 10 ohm 9317C 9318C 8 Input A D Cal Input A D Verify Current Verify Current Verify Current Verify Current Verify COPYRIGHT 12 87 LSCI R27 BATA e ex OUT 333333233 m R15 R17 Y SK R19 R18 i 37K 316 2323233223 33 9 01 Figure 9317C 1 Model 931 7C Resistance Input Card REPLACEABLE PARTS LIST 101 137 101 067 101 025 105 405 104 509 104 652 104 001 104 345 104 419 104 060 104 078 104 465 104 089 104 098 104 020 104 660 103 990 166 14
206. n Option Curves is given in Appendix B Figure 2 3 SENSOR ID Definitions SENSOR ID SENSOR ID Negative T C Positive T C Continuous Update Digital Filter On No Thermal Cnsdrd Thermal Considered Curve Selection Position selection Multiple Bit 3 Multiple Bit 2 Multiple Bit 1 Multiple Bit O Table 2 4 SENSOR ID Standard Curve Address Model DRC 91C See SECTION III for more informa tion on sensor selection and the operation of the SENSOR ID switches and J5 REMOTE SENSOR ID Note that Curve 10 is given twice Curve 02 has a set point limit of 325K and Curve 04 has an upper limit of 475 kelvin Switch 4 of the SENSOR ID must 0 for the instrument to read the curve directly from the rear panel SENSOR ID hardware If a thermocouple card is present the SENSOR ID switches select the appropriate thermocouple table instead of the diode or platinum curves 2 3 9 Heater Power The heater output leads should be electrically isolated from the sensor s ground s to preclude the possibility of any of the heater current affecting the sensor input signal The heater leads should not run coincident with the sensor leads due to the possibility of capacitive pick up between the two sets of leads If they are in close proximity they should be wound so as to cross the sensor leads at ninety degrees if at all possible The heater output is a current drive and does not have to be fused The DRC 91C is
207. n the test 1 Digital Voltmeter 4 resolution or better digit Model DRC 91C 2 Test Connector fabricated per Section 5 5 1 Complete the following set up procedure for this test 1 Plug the connector into INPUT A 2 Connect the DVM across the test resistor of Input A 3 Connect the DRC S51C to line power and turn the unit ON Verify that the DRC 91C initial izes to the proper POWER ON state as defined in Section 3 7 The following procedure is used to test the overall DRC 91C operation Note The unit should be allowed a one hour warm up time to achieve rated specifications 5 5 3 Current Source Check The DVM across the test resistor should read as follows 9210 20 3 1 0000V 100 9210 20 6 1 0000V 100 9220 2 0 10000V 104V 9220 3 0 10000V 1 9220 1 0 03000V 10 9317C N A 9318C N A 5 5 4 Monitor Voltage The voltage across the sensor or test resistor is also available on the monitor plug The connections are given in Section II of this manual The monitor voltage will be equal to the sensor voltage for 3 volt 3 diode inputs and all platinum 2 P3 and rhodium iron R1 inputs If the input is a GaAlAs Diode 6 input then the monitor voltage will be 0 458 times the sensor voltage This test is not applicable for the 9215 9305 9317C or 9318C input cards COPYRIGHT 3 88 LSCI Model DRC 91C 5 5 5 Temperature Display 5 5 5 1 Determine Input
208. nd synchronize the transmission and receipt of data The baud rate is switch selectable at 300 or 1200 baud and the interface maintains EIA voltage levels for data transmission Figure 8223 2 gives a transmission format which shows the data bits framed by the start stop synchronization bits The data is transmitted using two voltage levels which represent the two binary states of the digit A logic O or SPACE is 3 to 12 VDC A logic 1 or MARK is 3 to 5 VDC When data is not being transmitted the line is held low MARK state When the transmission device is ready to send data it takes the line to the high SPACE state for the time of one bit This transition is called the start bit The remaining data 15 then transmitted If a parity bit is used it follows the character The parity bit is determined by the COPYRIGHT 12 87 ISCI Table 8223 2 number of 1 bits in the character Refer to Table 8223 1 for parity determination Table 8223 1 Parity Determination umber of 1 s Parity Parity pun ema Specified Odd 0 zd Odd 1 Odd Even 1 Even 0 ihe Model 8223 RS 232C Interface has a 25 pin D style connector located on the rear panel Pin Assignments shown Table 8223 2 Connector Pin Assignments for RS 232C sm Protective Ground Transmitted Data Received Data Request to Send Clear to Send Data Set Ready Signal Ground Rcvd Ln S
209. ne feed CR LF or just line feed LF as its input EOL and transmits carriage return line feed CR LF as its output EOL Following the EOL Sequence the command string is processed Operation of the Interface link is initiated by the computer The computer will transmit either a Program Code or an Output Request to the 8223 Interface The DRC 91C 93C will respond to the Output Request with the appropriate response or with the response and an error message if an error was 8223 4 Model DRC 91C 93C detected interface responds to Program Code Commands by storing the variables input The Programming Codes given Tables 4 4 4 7 and 4 8 are input only do not result in response from the interface The Codes IN and ZN will be accepted and updated even though they have no relevance to the interface the EOL terminator sequence is always LF and there is EOI status The MN command can be considered the OFF LINE Local and ON LINE Remote or Remote with Local Lockout states When OFF LINE Local parameters such as SENSOR ID as well as Gain Rate and Reset are updated from the hardware settings while ON LINE these parameters can be updated from the computer only The Output Statement commands given in Tables 4 9 and 4 10 will result in the requested data being output immediately following the reception of the EOL sequence If more than one Output Statement command is given
210. ng characters are changed by the user these are only in effect until the instrument is turned off 4 4 2 TALKER and or LISTENER Configuration Since the DRC 91C is both a TALKER and a LISTENER normally switches two and three should both be OPEN 0 These switches are usually of setting for all Hewlett Packard use when one instrument is a TALKER computers and another instrument is a LISTENER and they are to share the same address Figure 4 1 IEEE 488 Address Switch for the DRC 91C D D L 16 8 4 2 1 CLOSED 1 OPEN 0 Address switches 4 is MSB 16 8 is ISB 1 Switch 3 CLOSED 1 position sets the 91C in the talk only mode by disabling LISTENER capability Switch 2 CLOSED 1 position sets the 91C in the listen only mode by disabling TALKER capability Switch 1 used to define the instrument s delimiters Refer to Section 4 4 1 of the text for details COPYRIGHT 3 88 ISCI 4 3 Model DRC 91C 5 Decimal Code Bit 1 Address Switches 3 4 5 6 7 8 2 Allowable Address Codes for the DRC 91C Factory preset address is decimal 12 m O 0 m IV Table 4 2 ASCII Code Character Listen Talk We Om V The sixth and seventh bits BUS CONTROLLER originated determine whether the instrument is being addressed to TAIK or LISTEN Only the first five bits of the binary code are These bits are the same for t
211. ngs do not match then the input card should be calibrated If the moni tor reading is incorrect and can not be adjusted then the following IC s may need to be replaced Old Input cards 1 8210 8211 cards replace U5 2 8219 8220 cards replace 05 If that does not solve the problem then replace U4 New Input Cards 1 9210 9220 cards replace 05 2 For the 9318C the monitor volt age should be approximately 10mV If it is not between 5 16mV then 016 U13 or 010 could be bad For the 9317C the moni tor voltage should be approxi mately a factor of ten lower The same three IC s involved If the monitor voltage is incor rect the input card may control at an offset or not at all If the sensor voltage matches the monitor voltage and the display voltage is incorrect then the A D needs to be calibrated 5 7 2 Units Display is correct but If the units display matches the voltage or resistance value of the sensor but the temperature display is incorrect then check the curve selected This can be accomplished by holding down the LOCAL button or by reading the selected curve over the interface using the W1 command If the correct curve is selected COPYRIGHT 3 88 Section V but the display in temperature is Still incorrect then check the data in the curve This can be done over the IEEE by using the test program and the XDN4N5 command 5 7 3 The Heater Circuit If the DRC 91C does not hav
212. nism Any method of clamping the sensor must avoid excessive pressure and should be designed so that thermal contractions or expansions do not loosen contact with the sensor For uses restricted to below 325 K a thin layer of Apiezon N Grease should be used between the sensor and sample to enhance the thermal contact The SD package can also be bonded with an epoxy such as Stycast The sensor should be pressed firmly against the surface during curing to assure a thin epoxy layer and good thermal contact The device may be removed in the future by using the appropriate epoxy stripper The SD adpater can be soldered using a rosin flux non corrosive if extreme care is exercised First tin the base of the sensor using a low wattage temperature controlled soldering iron which will not exceed 200 C Use only a minimal amount of solder Tin the surface to which the sensor is to bonded and again avoid an excessive thickness of solder Clean both the sensor and mounting surface of any residual flux Next re heat the mounting surface to the melting point of the solder press the device into position and allow the sensor to warm to the melting point of the solder After both tinned surfaces have flowed together remove the heat source and let the sample and sensor cool Under no circumstance should the sensor be heated above 200 C and the solder must be limited to only the base of the sensor Excess solder running up the sides of the SD package can create shor
213. nnector access plate 711 3912 COPYRIGHT 12 87 ISCI Model DRC 91C REAR PANEL DESCRIPTION 3 13 REMOTE SENSOR ID The REMOTE SENSOR ID connector receives position data from a Model 8084 or Model 8085 Sensor Scanner or Model SW 10A ten position switch This input allows the user to automatically call up different curves for different sensor channel positions when the instrument is used with either remote switch see Section 3 10 2 The Parallel input data format is given in Table 3 5 Table 3 5 Assignments for the J5 REMOTE SENSOR ID Connector J5 CONNECTOR Pin Assignments 151311 9 7 5 3 1 16 14 1210 8 6 4 2 ONLY BOLD PINS USED Bit 3 Bit 2 Bit 1 Bit O LSB DIGITAL GROUND Bit 4 MSB COPYRIGHT 12 87 LSCI Section III The user may supply to the REMOTE SENSOR ID his own parallel BCD 5 volt signal referred to the DIGITAL GROUND on pin 12 3 14 HEATER CURRENT LIMIT The DRC 91C Temperature Controller has a current drive output with a maximum current rating of one amp ere unless the optional 1 5 ampere output W60 was ordered or the current limiting vernier has been set at a lower value With the current limiting vernier on the back of the instrument the output current on the MAX scale can be limited anywhere between 1 amp ere and the maximum current for the 1071 scale 330 mA This allows the user to limit the maximum power to between 25 watts and 2 5 watts dependent on his req
214. ns The four lead connection is required for a four lead sensor use of a four wire connection Figure 2 2b is highly recommended for two lead resistive elements and diodes to avoid introducing drops in the voltage sensing pair which translates into a temperature measurement error An alternate two line wiring method Terminals A and E shorted toget her B and D shorted may be used for the DT 470 and TG 120 series diodes in less critical applica tions where lead resistance 15 small and small readout errors can be tolerated c Measurement er rors due to lead resistance for a two lead hook up can be calculated using T IR dV dT where I is 10 microamperes R is the total lead resistance dV dT is the diode sensitivity and 6T is the measure ment error For example R 2500 with dV dT 2 5 mV K results in a temperature error of 1 kelvin Two wire connections are not recom mended for other sensor types Table 2 2 INPUT Connections for J1 Input A and J2 Input B Current Out Current Out Voltage Sense Voltage Sense Shield The Lake Shore Cryotronics Inc QUAD LEAD 36 Gauge Cryogenic wire is ideal for connections to the sensor since the four leads are run together and color coded The wire COPYRIGHT 12 87 LSCI Section II is Phosphor Bronze with a Formvar insulation and Butryral bonding between the four leads Color cod ing is red green clear and blue on the four leads w
215. ns the heat input required to maintain a set point temperature is approximately constant This is because the heat loss through a fixed thermal conductance to the room temperature environment outside the furnace is also constant However there are cryogenic systems where the low temperature environment provided by e g a surrounding cryogen such as a liquid helium or liquid nitrogen bath may vary drastically as the level of the cryogen changes In addition the thermal conductance to the outside world is highly dependent on the gas pressure vacuum maintained in the cryostat The resulting variations in cooling power will cause the heat input requirements to be anything but constant A few cryogenic systems employ a controller cooling loop but this type of system will not be discussed Most of the difficulties in cryogenic control applications are associated with factors 4 and 5 where changes in parameters are involved Application Notes 1 Lake Shore Cryotronics Inc PROPORTIONAL CONTROL The block diagram in Figure 1 shows a systems in which only proportional control is being used In this system the desired control temperature setting set point is being compared to the sensor signal and the difference or error signal including polarity is amplified within the controller When the sensor temperature corresponds to the set point temperature in voltage for a diode or resistance for a resistor the sensor signal will be equa
216. nsor sensitivity of 50 mV K B corresponds to a sensor sensitivity of 2 5 mV K Note that the curves are linear in voltage not power producing the error signal in Figure 2 had a sensitivity of 1 mV K and the set point full scale range was 100 mV 100 K The proportional band would then be 8 or 8 and 80 or 80 K for A 1000 and 100 respectively In cryogenic applications this terminology is less significant gain which is multiplicative is usually more useful since it is more easily understood by the user The power output stage of a cryogenic controller may or may not have variable gain associated with it If the controller has several output power stage ranged for example 5 covering 5 orders of magnitude in power as does the DRC 82C then the controller output into a 50 ohm load and with a gain of 200 for 5 watts and 50 watts would have the response shown in figure 3 Note that the overall voltage and power gain of the controller is modified by changing the output power settings Application Notes Lake Shore Cryotronics Inc To illustrate the effect of the sensor in more detail consider the idealized curve Figure 4 for a Lake Shore silicon diode which has a nominal sensitivity of 50 mV K below 30 kelvin and 2 5 mV K above 30 kelvin Figure 3 illustrates the effect of converting the voltage error signal horizontal axis to its equivalent temperature error for the two sensitivity regions of 2 the silicon dio
217. ntrol Sensor COPYRIGHT 12 87 LSCI Table 8225 1 Model 8225 Analog Output Specifications Output Range 0 000 to 10 000 V Output Resolution out of 10V Output Resistance Less than 100 Output Equivalence Temperature for all Input Cards Output 0 000 to 9 999 V for display of 0 to 999 9 Sensitivity 10 mV K Voltage for 9210 and 9220 Output 0 0000 to 6 554 V for display 0 0000 6 5535 V Sensitivity 1 V V Resistance 9220 P2 P3 and R1 8 P2 Output 0 000 to 3 000 V for display 0 00 300 00 D Sensitivity 10 mV ohm P3 3 Output 0 000 to 3 000 V for dispiay 0 0 3000 0 f Sensitivity 1 mV ohm Rl Output 0 000 to 10 000 V for display 0 000 99 999 n Sensitivity 100 mV ohm Note The resistance of the 9317C and 9318C Input Cards is not output by the 8225 because of the number of orders of magnitude the display cover The analog output of temperature displayed by these Input Cards is available if a Precision Option is present for the sensor 8225 1 Model 8225 Analog Output WARNING To prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment before removing cover 2 Set the power switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off Note on the calibration cover the position of Option Slot 1 or 2 which the 8225 will occu
218. ocedure being careful to use spacers or suitable packing material on all sides of the instrument COPYRIGHT 12 87 LSCI Model DRC 91C SECTION OPERATING 3 1 INTRODUCTION This section contains information and instructions concerning the operation of the Model DRC 91C Temperature Controller Included is a description of the front and rear panel controls and indicators 3 2 INSTRUMENT CONFIGURATION 3 2 1 Input Card Configurations Model DRC 91C can be used with either one or two input cards The input cards available for use with the DRC 91C are summarized in Sec tion I The input cards available allow the 91C to be used with al most any type of cryogenic sensor Input cards can be mixed allowing two different sensor types to be used with the DRC 91C 3 2 2 Single Input Card When only one input card is present within the unit it occupies the A INPUT CARD slot of the DRC 91C mainframe and is connected to the Sensor input of the controller Only one sensor can be used with the controller under these condi tions 3 2 3 Dual Input Cards When two input cards are present in the unit the input card that oc cupies the A INPUT CARD slot is routed to the Sensor A input and the input card that occupies the B INPUT CARD slot is routed to the Sensor B input Consequently both sensors are energized at all times second input card allows the instrument to mix sensor types e g both a diode thermome
219. ogenic system For example assume that 5096 output is required and the time to reach equilibrium is 3 seconds 05 minutes Therefore the repeats per minute is 10 and the time constant is 0 1 minutes In actuality this is not easy to determine without a few tries Almost always however the time constant increases with increasing temperature so that if one is operating over a broad temperature range finding the appropriate time constants for the two extremes will bracket the appropriate time constants within that temperature range Once the correct time constant has been selected the system should settle to its control set point within two or three time constants If significant overshoot is still occurring the system design should be carefully reviewed V ADDING DERIVATIVE RATE TO THE TEMPERATURE CONTROL LOOP If there is still an overshoot of the control temperature during transient changes of the set point within one s system it can be significantly reduced by the addition of a third control function to the controller called rate or derivative control Normally overshoot can be attributed to one of two causes 1 the application of much more power than is required to maintain the system at its desired set point or 2 the result of the thermal response relationships between the cooling power the heating power and the control sensor The best solution to the first possibility is to reduce the available power as discussed previously The sec
220. oint current range and value have been reached In this way the heater remains off until the actual sensor resistance approaches the set point resistance Once the final control sensor current value has been reached the 9317C 9318C allows the sensor voltage to range as high as 1 3 9318C millivolts If the sensor voltage and the equivalent resistance continues to increase an under temperature condition exists the 9317 9318 then reduces the current to maintain between 1 1 and 1 3 9317C or 11 and 13 9318 millivolts across the sensor The heater power remains on Even though this operation takes the sensor voitage away from the optimum signal until it reaches the control point the resulting error in the resistance determination is small If the new 9317C or 13 COPYRIGHT 12 87 LSCI 9318c 9317C 9318C Input Cards set point results in an under temperature condition the opposite operation is performed thermal correction is the 91C 93C monitors the sensor resistance until it is within 0 5 of the set point resistance Once it is the 91C 93C signals the 9317 9318 card to reverse the sensor current and update the thermal value The 9317C 9318C card the 91 93 use this new thermal to determine the resistance and correct the set point The thermal value is updated every 120 instrument update cycles about 2 minutes after the initial update When the set point is changed the previous
221. oltage reading across the diode when operated with an ac dc current and the dc voltage reading when operated with a pure dc current see Fig 2 At first glance the logical choice seems to be to examine the variation of this offset as a function of the ac current amplitude However the ac rms voltage across the diode was chosen instead for two reasons the first of which is purely practical many circumstances the ac voltage measurement can be made without any modifications to existing measurement systems so laboratory checks can be quickly taken and compared directly to the data presented here to give an estimate of potential temperature errors Second in the calculations using the model presented below one unknown parameter could be eliminated from the calculations by using the voltage across the diode instead of the current Figures 4 and 5 give the offset voltage as a function of the ac rms voltage across the diode for dc currents of 1 10 and 100 pA with the ac current modulation at 60 Hz The equivalent temperature error corresponding to the dc offset voltage is indicated along the right edge of the figure Figures 6 and 7 give similar plots but at a fixed 10 uA dc current with the ac current modulation at 60 1000 and 20 000 Hz The magnitude of the dc offset voltages is consistent with what has been observed in measurement systems when corrective action has been taken to eliminate noise problems Special note should be taken of the
222. ommand The XDN N gt command is used to output a particular Sensor Curve rather than all the curves stored within the instrument as in the XDA command with N4N5 being the curve number 00 thru 31 format of the Sensor Curve output is given in Table 4 17 The information is output as one very long character string The following program is for the HP86B and is an example of the XDN N5 to output Sensor Curve 00 4 27 Section IV Model DRC 91C Table 4 16 Sensor Curve Commands and Description Commands Output of Information Table Sensor Curve or All Curves XDT Output the Sensor Curve Information Table Refer to Table 4 17 for the format of the output 1 2 Output Sensor Curve number where N4N5 is from 00 to 31 Refer to Table 4 18 for the format of the Sensor Curve output XDA Output the Sensor Curve Information Table XDT and all the Sensor Curves stored in the unit Refer to Table 4 17 for format of the Information Table output and Table 4 18 for format of the Sensor Curve output Curve Input Curve Edit and Curve Erasure Sensor Curve Input NN is Sensor Curve number from 06 to 31 Immediately after Sensor Curve XCN1N2 a comma is required Up to 18 characters can be input as a curve description When all 18 characters are input the last 6 are used in the Sensor Curve table in the 8000 Series Precision Option curves these 6 characters are used to indicate
223. on Table SENSOR ID Switch 4 1 Correlation Table INPUT B 0010000 10001 10010 10011 10100 10101 10110 10111 11000 11001 11010 11011 11100 11101 11110 11111 Lo 2 J a n ar es S ascen Debe io a El J It is possible to store up to 31 curves total in the DRC 91C These additional Precision Option Curves 25 possible if present can be accessed by means of the Position COPYRIGHT 12 87 5 Section III Number versus Correlation Table The first 10 Precision Options Curves 06 through 15 can also be accessed through either SENSOR with Switch 4 open 0 Curve Number J 10 2 SENSOR ID Switch 4 Closed 1 No REMOTE SENSOR ID Present With no external Remote Position i e REMOTE SENSOR ID reading 00 and SENSOR ID switch 4 closed 1 switches 5 through 8 give an equi valent sensor position the Position versus Curve Correla tion Table 3 4 Column 2 It is therefore possible to assign any curve number 00 through 30 to any of 16 positions 00 through AOF for the A SENSOR ID and BOO through BOF for the B SENSOR ID 3 10 3 SENSOR ID Switch 4 Closed 1 REMOTE SENSOR ID Present Up to three 8084 or 8085 Scanners can be daisy chained together to give 30 remote positions for either t
224. ond problem normally occurs with a large thermal mass where response is slow and overshoot due to the thermal inertia of the system can be quite large This overshoot is caused by the time lag between a change in output power and the control sensor sensing this change In very large non cryogenic systems this time lag can be 10 30 minutes In cryogenic systems it is usually less than a minute even near room temperature Consequently placement of the control sensor with respect to the heater is extremely important in the design of a cryogenic system as is the placement of both the heater and sensor with respect to the cooling power Rate action can be achieved by means of a differentiator circuit which provides a signal proportional to the rate of temperature change and 450 which is subtracted from the proportional output signal This reduces the effective overall amplifier gain driving the output power stage The reduced gain effectively increases the proportional band of the controller This slows down the rate of temperature rise and therefore allows more time for the block to stabilize Consequently the overshoot is substantially reduced or eliminated depending on the magnitude of the thermal problem as is indicated in Figure 6 100 Without Rate The addition of rate is necessary only because of inherent thermal problems which cannot be substantially eliminated by improvements in thermal design Also note that rate is effective only dur
225. ons for the communication 4 5 2 The Universal Commands shown in Table 4 3 are those multiline commands that address all devices on the bus A multiiine command involve a group of signal lines COPYRIGHT 3 88 LSCI Section IV All devices equipped to implement such commands will do so simultanecusly when the command is transmitted As with all multiline commands these commands are transmitted with ATN line asserted low There are two Universal commands recognized by the DRC 91C LLO Local Lockout and DCL Device Clear LLO Local IOckout LIO is sent to instruments to lock out prevent the use of their front panel controls DCL Device CLear DCL is used to return the DRC 91C to the power up conditions 4 5 3 The Addressed Commands shown in Table 4 3 are multiline commands that must include the DRC 91C listen address before it will respond to the command in question Note that only the addressed device will respond to these commands The DRC 91C recognizes three of the Addressed commands SDC Selective Device Clear GTL Go To Iocal and SPE Serial Poll Enable SDC Selective Device SDC command performs essentially the same function as the DCL command except that only the addressed device responds Generally instruments return to their power up default conditions when responding to the SDC command Go To Local The GTL command is used to remove instruments from the remote mode
226. ons for use with the DRC 91C Temperature Controller Each Accessory Input Card and Option is listed by part number in the Table on page 6 1 6 2 ACCESSORIES 6 2 1 RM 3F Rack Mounting Kit The DRC 91C can be rack mounted in a Standard 19 inch instrument rack by using the RM 3F Rack Mounting Kit The RM 3F mounts controller in a height of 3 5 inches Use the following procedure to install the RM 3F Kit l Remove the two blue rack mount access covers if present from the front side corners of the unit to be rack mounted This is easily done by sliding the cover up as far as possible and using a blade screwdriver on the bottom edge to remove it from its position 2 If the H handles option was added mount the handles onto the rack ears 3 Attach the rack ears on opposite sides of the unit 6 2 2 Cables 6 2 2 1 8072 488 Interface Cable The 8072 IEEE 488 Interface cable is one meter long and is equipped with double ended connectors so it may interconnected in serial or star patterns common IEEE 488 instrument configurations 2 The Model DRC 91c 6 2 2 2 8271 04 Scanner Sensor Cable The 8271 04 Scanner sensor cable for the 8229 Scanner Card is 3 meters long and brings out leads for the four additional input sensors provided by the 8229 Option The cable s mechanical and electrical specifications are included with the cable 6 2 2 3 8271 21 Sensor Heater Cable The
227. or excess moisture 2 7 1 Operating Temperature In order to meet and maintain the specifications in Table 1 1 the 2 6 Model DRC 91C DRC 91C should be operated at an ambient temperature range of 23 C 4 5C The unit may be operated within the range of 15 35 with less accuracy 2 7 2 Humidity Altitude The DRC 91C is for laboratory use and no humidity or altitude speci fications have been determined for this unit 2 8 REPACKAGING FOR SHIPMENT 17 the Model DRC 91C appears to be operating incorrectly refer to the Technical Service Guide for troubleshooting advice If these tests indicate that there is a fault with the instrument contact ISCI or a factory representative for a Return Goods Authorization RGA number before returning the instrument to our service depart ment When returning an instrument for service the following information must be provided before Lake Shore can attempt any repair 1 Instrument Model and Serial 5 2 User s Name Company Address and Phone Number 2 Malfunction Symptoms 4 Description of system 55 Returned Goods Authorization i If the original carton is avail able repack the instrument in a plastic bag place it in the carton using original spacers to protect protruding controls Seal the carton with strong paper or nylon tape Affix shipping labels and FRAGILE warnings If the original carton 15 not available pack the instrument similar to the above pr
228. orted 6 not supported 7 Supported 8 not supported Note settings not interface respond but the card has not been tested with these settings at tbe For tne the supported will factory X is a don t care setting for that switch 8223 4 SPECIFICATIONS Specifications for the Model 8223 RS 232C Interface are given Table 8223 5 8223 5 INSTALLATION The 8223 RS 232C Interface is factory installed if ordered with a DRC 91C Temperature Controller or can be field installed at a later date If field installation is required use the following procedure 1 Configure the 8223 baud rate and word structure switches as outlined in Section 8223 3 COPYRIGHT 12 87 LSCI Model 8223 RS 232C Interface Table 8223 5 Model 8223 RS 232C Interface Specifications Timing Format Asynchronous Transmission Mode Half Duplex Baud Rate 300 or 1200 Bits sec Factory set to 300 Bits per Character 7 excluding start stop or parity bits Parity Enable Enabled Disabled Factory set Enabled Parity Select Odd or Even Factory set Odd Number of Stop Bits 1 2 Factory set to 1 Data Interface levels Transmit or receive using EIA voltage levels 12V and 5 WARNING To prevent shock hazard turn off the instrument disconnect it from AC line power and all test equipment before removing cover 2 Set the POWER switch to OFF and disconnect the power cord from t
229. ote Although limitations on the range of the set point are set within the software when in temper ature units these limits are not possible for sensor units due to the different characteristics for each sensor Model DRC 91C Since the set point is soft the transition from REMOTE to LOCAL does not result in a change in the set point 4 9 2 The WP Request Data String This request is a subset of the WO command the WP command giving the set point value by itself Table 4 9 DRC 91C Command Request Summary for Setpoint Setup Functional Description Set Point Input units Units Sensor The decimal point is FREE FIELD and its allowable position depends on the control Limits are The Set Point is limited based on input card and Lower limit is 0 K 273 1 C or 459 6 OF through 999 9 999 9 through 999 9 0 0000 through 9 9999 0 through 99999 0 through 99 999 or 999 99 9210 20 3 9210 20 6 9317C DT 470 DT 500 TG 100 TG 120 Germanium Carbon Glass 9318C Germanium Carbon Glass 9215 15 5 400 5 501 9215 150 5 401 5 501 9210 20 3 DT 470 PT 100 Series PT 1000 Series Rhodium iron 999 9 526 7 980 1 Upper Set Point Limit K e Sensor Units 2 9999 volt 6 5535 volt 9999 9 ohms 99999 ohms 29 999 nF N A 149 99 nF 474 474 9 201 7 395 1 2 9999 volt 299 99 ohms kkkkk
230. other system Control Modes GAIN integral RESET and derivative RATE Set via front panel knobs or with interface Heater output Up to 25 watts 1A 25V standard Four output ranges can be selected either from front panel or interface provide approximate decade step reductions of maximum power output Optional 50 or 60 watt outputs available Rear panel maximum current limit for MAX scale Proportional Heater output Monitor LED display continuously shows heater current or power output as a percentage of range with a resolution of 1 Control Sensor Either Sensor Input designated from rear panel General Sensor Voltage Monitor For 9210 and 9220 diode Option configura tions 3 6 buffered output of diode sensor voltage Multiplier COPYRIGHT 1 88 LSCI Section I is 0 457771 for 6 configurations For 9220 Option positive tempera ture coefficient configurations P2 P3 R1 buffer is sensor voltage output times 10 Buffered outputs for 9210 6 and 9220 6 are multiplied by 0 457771 For 9215 signal is proportional to capaci tance value for 9317C 9318 monitor not of use Response time electronics Less than 1 second to rated accuracy for non Lagrangian calculations Lagrangian curves result in update times between one and two seconds Three readings on channel change or range change to reach rated accuracy IEEE 488 Interface Allows remote control of set point gai
231. ouple to it s standard curve and system confiquration Controllability Typically 0 2K in a properly designed system Display Resolution 5 digits Compensated and uncompensated voltage in millivolts from 0 000 to 15 000 or temperature in Celcius Fahrenheit and Kelvin Note When displaying millivolts the unit V is shown Temperature Control Signal Card processes an analog voltage output signal 200 times the thermocouple voltage The instrument generates setpoint voltage based on the voltage or temperature entered by the user If compensation is enabled the setpoint voltage is modified to reflect the compensation required Real time analog comparison of these two voltages provides the required control error signal 9305 2 COPYRIGHT 6 88 LSC Model DRC 91C 93C Table 9305 2 Chromel vs 0 07 at Fe Remove the four screws that secure the calibration cover to its clips and remove the cover If the 9305 is to replace an existing Input Card unplug the Input Card which is to be replaced Disconnect the wiring harness mating connector by lifting the locking tab on the Input Card gently pulling on the body of the Wiring harness mating connector Attach the Thermocouple Terminal Block into the Alternate Connector Slot J9 if the Card is Input A or in Alternate Connector Slot J11 if the Card is Input B with the wires facing the input Slots are shown Figure 3 2 Uncovering the Connector Slot
232. perating at 77 K The symbols represent data recorded at 10 dc current with the ac current modulation at 60 1000 and 20 000 Hz 10 4 2 10 uA 10 S F gt 10 lt e 2 e A e A 60 Hz 10 1 kHz 20 kHz 1 0 4 8 12 16 20 24 28 32 RMS AC VOLTAGE mV FIGURE 7 DC offset voltage as a function of rms ac voltage across a silicon diode temperature sensor operating at 77 K The symbols represent data recorded at 10 dc current with the ac current modulation at 60 1000 and 20 000 Hz 17 Lake Shore Cryotronics Inc IV CONCLUDING REMARKS Noise in any measurement circuit is undesirable and should be eliminated to as great an extent as possible The first step is to electrically shield all instrumentation and wiring and use proper grounding techniques Secondly the diode measurement circuit should have a single circuit ground which is generally made at the voltmeter and which then requires a floating current source The installation of the diode and its connecting leads should be done carefully to avoid introducing any unwanted circuit ground connections such as an electrical short to a cryostat As last resort a quick fix be used to eliminate much of the dc offset voltage with some degradation in the diode circuit performance A good quality capacitor low leakage can be placed across the diode to shunt the induced ac currents similar to the test procedure used for id
233. place fuse holder close fuse compartment and connect power cord 5 4 LINE VOLTAGE SELECTION The rear panel three pronged line power connector permits the DRC 91C to be connected to 100 120 220 or 240 VAC line voltages Use the following procedure to change the line voltage Section V To prevent shock hazard turn off the instrument and disconnect it from AC line power and all test equipment before changing the line voltage selection 1 Pull fuse compartment cover using the procedure found in Section 5 3 2 Remove voltage selector wheel and insert with the proper vol tage facing out Note that the wheel can only be inserted with the writing read from the left 3 Install the proper fuse as out lined in Section 5 3 5 5 OPERATIONAL CHECKS 5 5 1 Test Connector A test connector for the rear panel 1 INPUT A J2 INPUT B connector to simulate a diode sensor input is required for operational checks of the DRC 91C The test connector can be made by taking one of the plugs supplied with the DRC 91C and configuring a resistor to simulate the temperature sensor in the two wire configuration as described in Section 2 3 6 The test resistors specified in Table 5 1 are used in the operational checks 5 5 2 Operational Test Procedure The operational test procedure is designed to verify the overall operation of the DRC 91C and can be used as a periodic maintenance check The following equipment is used i
234. portant to consider sensor performance when designing a complete system The Lake Shore DT 500 Series Sensors have a voltage temperature characteristic which lend themselves to cryogenic temperature control use because of their high sensitivity at low temperatures Figure 3 Coupled with this sensitivity is an extremely low noise level which results in part from assembly techniques used for all DT 500 Sensors which comply with the relevant portions of MIL STD 750C It is therefore possible to obtain short term control at low temperatures which can approach 0 1 mK in specially designed systems such as the Lake Shore calibration facility Even above 30 K where the sensitivity is reduced by a factor of 20 short term controllability is better than 2 mK With diodes there is no need for a sensor pre amplifier which would precede the set point control and deviation amplifier However in the case of resistance thermometers including both semiconductor and metal types a pre amplifier becomes necessary In a dc measurement system such as is used in the DRC 82C it is sometimes possible to obtain temperature control stability with resistance thermometers superior to that obtainable with diodes This requires a highly stable and adjustable constant current source in addition to a pre amplifier designed for very low noise and drift The choice of sensor is not at all obvious it depends on many factors besides sensitivity including sensor size time response
235. power line cycles without using the filtering options available on the voltmeter The average of several readings was taken to reduce the measurement uncertainty An oscilloscope was also used to double check and monitor signal frequency shape and distortion but the FIGURE 3 Measurement circuit schematic diagram oscilloscope was removed from the circuit when actual data were recorded Data were recorded at the three dc current values of 1 10 and 100 pA with the temperature stabilized at 305 77 or 4 2 K At each temperature and dc current value the dc voltage and the ac voltage across the diode were recorded as the amplitude and frequency of the signal generator were varied The dc voltage reading across the 10 kQ standard resistor was also monitored to verify that the dc component of the current remained constant to within 0 05 In addition the IV characteristic of the diode was measured at each temperature from 0 1 to 150 UA Although detailed measurements were taken on only one diode other diodes were randomly selected and spot checked at all three temperatures and frequencies to verify consistency with the measured data The diodes tested were of the DT 500 series of Lake Shore Cryotronics Inc and have been in production long enough to have a substantial reliability and calibration history RESULTS AND DISCUSSION The data were analyzed by calculating a voltage offset AV This offset is defined as the difference between the dc v
236. py 3 Remove the four screws that secure the calibration cover to its clips and remove the cover 4 Plug the 8225 printed circuit board into Option Slot 1 or 2 with the component side to the left of the unit as viewed from the front Thread the two black and white wires from the 8225 along the inside edge of the rear panel and solder the white wire to MONITOR connector 93 Pin C and black wire to Pin D 5 Install the calibration cover by reversing procedure in 3 6 Install the top panel 8225 5 OPERATION resolution and equivalence is given Table 8225 1 For a temperature display of 100 00 K the 8225 would output 1 000 V The output is rounded to the equivalent unit for the 1 mV output display of 23 42 K would result in an output of 0 234 V and a display of 23 47 K would result in an output of 0 235 V The output 8225 6 CALIBRATION The Model 8225 has been calibrated to specification prior to shipment 8225 2 Model DRC 91C 93C If re calibration is needed use to the following procedure The following equipment used to calibrate the 8225 Analog Output 1 Digital Voltmeter Multimeter DVM 44 digit resolution or better 2 Precision Standard Resistor to simulate the input sensor or a Precision Voltage Source with an output resolution of 100 uV out of 3 V or better The unit should be allowed one hour to warm up to achieve rated specifications Use the following procedure to calibr
237. quivalent the RO command see Table 4 10 4 9 7 NOTE The Return to Local Although the Gain Rate Reset and Sensor ID s can be changed over the IEEE Bus with the 91C in REMOTE when the 91 returns to LOCAL these settings are read and updated from the hardware i e the front panel gain rate and reset and the SENSOR ID switches on the back panel 4 9 8 The W3 Data String The settings for the gain rate reset heater range as well as the instantaneous of Heater Power can be transmitted from the DRC 91C with the W3 command The command SPIDR or any combina tion without a value following the letter sets the chosen parameters to O e g SP sets the set point and gain to O Model DRC 91C 4 10 THE SCANNER INPUT CARD 4 10 1 SCAN Programming Instructions NOTE The YA YB and YC commands should be issued when the SCAN mode is Holding Changing a SCAN time or Scanner Channel while the unit is actively scanning may cause unpre dictable results 4 10 2 Setting the Dwell Time The YAN N5N3 and YBON SN Commands The time spent on a given scanner channel can be varied between O and 99 seconds setting the dwell time for that channel This can be done over the IEEE 488 Bus with these commands or from the front panel Setting the dwell time to O skips that channel 4 10 3 Selecting the Scanner Channel The YCAC Command The A channel input AO A1 A2 A3 Or A4 is selected by this command
238. r the gain is creased the output power will in crease Keep the LO lead of the DVM at 1 and move the HI lead to TP29 Turn off the GAIN RATE and RESET by entering a value of 0 0 for each The DVM will now read approximately 0 0 volts change the GAIN to 1 0 and the DVM will read approximately 0 1 volts which is the error Of 0 01 times the gain of 10 Change the GAIN to 10 and the DVM will read approximately 1 volt Setting the GAIN to 99 will result in a reading of approximately 7 2 volts 5 5 7 2 Reset Set up the con troller instructed step 5 5 6 1 Enter a gain and setpoint value that results in less than full power to the load If a Reset value is now entered the instru ment will try to integrate out the error With a test resistor in the control sensor input and a fixed setpoint the error signal will be constant With a constant error the Reset will continue to increase the analog output control signal until the heater display reads 100 percent If the heater output in creases to approximately 100 per cent for these conditions the reset circuit is operating To check the RESET circuit in more detail use the same set point and a GAIN of 10 Move the HI lead of the DVM to TP30 and enter a RESET of 1 0 The reading on the DVM should gradually integrate to ap proximately 7 2 volts The time required will depend on the amount COPYRIGHT 3 88 LSCI Model DRC 91C of reset with time required being
239. re to file appropriate claims promptly with the carrier and or insurance company Please advise Lake Shore Cryotronics Table 2 1 COPYRIGHT 12 87 LSCI Line Voltage Volts Operating Range Volts Inc of such filings parts shortages advise LSCI im mediately LSCI can not be respon sible for any missing parts unless notified within 60 days of ship ment The standard Lake Shore Cryotronics Warranty is given on the first page of this manual In case of 2 3 PREPARATION FOR USE 2 3 1 Power Requirements The Model DRC 91C requires a power source of 100 120 220 or 240 VAC 5 10 50 to 60 Hz single phase CAUTION Verify that the AC Line Voltage Selection Wheel Figure 3 2 Key 1 located on the rear panel of the Model DRC 91C is set to the AC voltage to be used Table 2 1 and that the proper fuse is installed before inserting the power cord and turning on the instrument Line Voltage Selection 90 105 108 126 198 231 216 252 Section II Figure 2 1 Model DRC 91C Typical Rack Configuration 2 3 2 Power Cord A three prong detachable power cord for 120 VAC operation which mates with the rear panel UL IEC ICEE standard plug is included with the instrument 2 3 3 Grounding Requirements To protect operating personnel the National Electrical Manufacturer s Association NEMA recommends and some local codes require instru ment panels and cabinets be ground ed This inst
240. respect to the voltage reading corresponding to lac When voltmeter operating in a dc voltage mode reads this signal the signal is processed by integrating filtering etc to give an average dc voltage reading which will be lower than expected The apparent temperature measurement will then be too high Note that this voltage offset is due to induced currents in the total measuring system and is not simply a voltage pickup by the diode itself An ac voltage superimposed symmetrically about the dc operating voltage of the diode would not cause a dc voltage offset 14 0 0 100 200 300 TEMPERATURE K FIGURE 1 Voltage temperature curve for a typical silicon diode temperature sensor at a constant current of 10 uA IV CURVE laccoswt FIGURE 2 IV curve for a silicon diode sensor showing effect of an induced ac current superimposed on the dc operating current lac The expected dc operating voltage is Vac which is shifted from the average voltage Vave indicated by the voltmeter in a dc measurement mode Application Notes Lake Shore Cryotronics Inc There are two simple techniques which can be used to test whether these errors might be present in a measuring system The first is to connect a capacitor about 10 pF in parallel with the diode to act as a shunt for any ac noise currents The capacitor must have low leakage current so as not to alter the dc current through the diode The capacitor may also
241. responding bit on the Status Register is set and a Service Request is issued if the SRQ bit of the mask is a 1 The user can check which overload or error was detected by sending the Output Data Statement WO See Section 4 12 2 and Table 4 15 For example in Figure 4 2 Q21 will allow the setting of the Overload Error Indicator and Display Data Ready bits in the Status Register but will not send an Service Request if either condition is met Q61 however will allow either of these bits to be set and when either is set an Service Request will be issued by the DRC 91C over the IEEE 488 Bus This Service Request Will remain on the Bus until either a Serial Poll is initiated or the cause of the setting of the SRQ is eliminated The Status Register mask and control channel limit is part of the power up save settings like the set point and units It is updated on power up to the last settings with internal switch 2 set If this switch is not set then the Status Register mask is set to 00 and the control channel limit to 000 0 COPYRIGHT 3 88 LSCI Model DRC 91C 4 11 3 5 Examples for setting Mask Example 1 Q61 Sample Data Ready with the Service Request bit SRQ on With the SRQ bit of the Status Register mask enabled the DRC 91C SRQ interrupt will generated The BUS CONTROLLER can read the Status Register to determine appropriate instrument conditions In this case bit 1 is continuously updated to reflect
242. rimeter Review of Scientific Instruments 52 1981 pp 895 901 R B Strem B K Das and S C Greer Digital Temperature Control and Measurement System Review of Scientific Instruments 52 1981 pp 1705 1708 Application Notes Lake Shore Cryotronics Inc Standard Curve 10 Standard Curve 10 Measurement Current 10 pA 0 05 dV dT T Voltage T Voltage T Voltage 1 69812 1 69521 1 69177 1 68786 1 68352 1 6 880 1 67376 1 66845 1 66292 1 65721 1 65134 1 64529 1 63905 1 63263 1 62602 1 61920 1 61220 1 60506 1 59782 1 57928 1 56027 1 54097 1 52166 1 50272 1 48443 1 46700 1 45048 1 43488 1 42013 1 40615 1 39287 1 38021 1 36809 1 35647 1 34530 1 33453 1 32412 1 31403 1 30422 1 29464 1 28527 1 27607 1 26702 1 25810 1 24928 1 24053 1 23184 1 22314 1 21440 19645 17705 15558 13598 12463 11896 11517 11212 10945 10702 10263 1 09864 1 09490 1 09131 1 08781 1 08436 1 08093 1 07748 1 07402 1 07053 1 06700 1 06346 1 05988 1 05629 1 05267 1 04353 1 03425 1 02482 1 01525 1 00552 0 99565 0 98564 0 97550 0 95487 0 93383 0 91243 0 89072 0 86873 0 84650 0 82404 0 80138 0 77855 0 75554 0 73238 0 70908 0 68564 0 66208 0 63841 0 61465 0 59080 0 56690 0 54294 0 51892 0 49484 0 47069 0 44647 0 42221 0 39783 0 37
243. rm the measured voltage into the normalized variable using Equation 2 Equation 1 is then used in combination with equations 3 and 4 to calculate the temperature Programs 1 and 2 provide sample BASIC subroutines which will take the voltage and return the temperature T calculated from Chebychev fits The subroutines assume the values VL and VU have been input along with the degree of the fit The Chebychev coefficients are also assumed to be in any array 0 1 A iaegree An interesting property of the Chebychev fits is evident in the form of the Chebychev polynomial given in Equation 4 No term in Equation 1 will be greater than the absolute value of the coefficient This property makes it easy to determine the contribution of each term to the temperature calculation and where to truncate the series if full accuracy is not required FUNCTION Chebychev Z as double as double FUNCTION Chebychev Z as double as double REM Evaluation of Chebychev series REM Evaluation of Chebychev series Z ZL ZU Z ZU ZL X 2 71 ZU Z ZU ZL 0 1 T 0 1 X FOR I 0 to Ubound A 0 1 FOR I 2 to Ubound A NEXT I Tc I 2 X Tc I 1 2 Chebychev T T T A I END FUNCTION NEXT I Chebychev T NOTE T X arccos X arctan END FUNCTION 2 1 y Program 1 BASIC subroutine for evaluating the Program 2 BASIC
244. rmal cycling over the long term weeks can result in variations that exceed degree These variations are always such that the equivalent temperature increases with time and with increased cycling The reduced capacitance C T C 4 2K for T 290K is stable to within 0 5 on the average Also these variations do not create instabilities and do not impair the sensors primary function control device in magnetic fields They also are not seen within a temperature cycle COPYRIGHT 2 88 LSCI 9215 Capacitance Input Card 9215 3 3 Magnetic Field Dependency Magnetic field sensitivity is less than 0 15 at 4 2K and less that 0 05 between 77K and 305K for fields up to 18 7 Tesla 9215 3 4 Frequency Dependence For frequencies between 1 and 5 kilohertz the frequency sensitivity is as follows 0 18K kilohertz at 4 2K 1K kilohertz at 77K 0 06K kilohertz at 305K 9215 4 INSTALLATION The 9215 can be installed in the DRC 91C 93C as either Input A or Input B The card is factory installed if ordered with a DRC 91C 93C Temperature Controller or can be field installed at a later date If field installation is required use the following procedure 1 Set the POWER switch to OFF and disconnect the power cord from the unit Remove the three top panel screws and slide the panel off Note on the calibration cover the position of the Card will occupy WARNING To prevent shock hazard turn off the instrument
245. rmanium Resistance Sensors 7 Carbon Glass Resistance sensors 8 Capacitance Sensors 9 Reserved for Thermocouples COPYRIGHT 5 88 B 1 13 thru 18 Stored in the Sensor Curve Information Table typically where the sensor serial number is stored in Precision Options sensor serial number formats are as follows where is used to indicate a 0 9 numeric Sensor Type Format D F Di HHHH PHHH No S N 0 1 2 3 4 5 6 7 8 9 B 2 COPYRIGHT 5 88 C DRC 91C Error Code Summary The error codes for the DRC 91C are separated into categories The Errox codes are for mainframe error conditions the Errlx codes are for Input Card error conditions If an ErrOx or an OL or Err2x error occurs for an input selected as the control input the heater range is taken to OFF and must be reset following correction of the fault condition The following is a summary of the error codes Possible Cause Corrective Action COPYRIGHT 5 88 The unit encountered an unwriteable NOVRAM data location When this error occurs the unit displays the error stores it in the WS data location and halts operation The NOVRAM initialization sequence should be performed to try to correct the problem If the error code still exists the NOVRAM needs to be replaced The unit performs a NOVRAM check on power up If the unit detects a NOVRAM data error or if the in
246. ros The Status Register Mask command is the ASCII letter Q followed by two alphanumerics representing the most Significant four bits and the least significant four bits respectively Note that the controller can be programmed for more than one set of conditions simultaneously To enable the Service Request Bit 6 must be a 1 4 11 3 1 Status Register Mask Bits O and 1 Display and Control Data Ready Enables If either Bit O or Bit 1 of the Status Register Mask is set 1 then for that data the corresponding bit in the Status Register is set when a valid data reading is available 4 11 3 2 Status Register Mask Bit 2 The Control Channel Limit Enable If the control channel limit Figure 4 2 Bit 2 is selected the limit must follow the Q command and is in a free field format Examples are 4 20 Model DRC 91C XXX X X X X XX X X etc If Bit 2 of the Mask is set 1 then when the control sensor reading gets within the chosen limit from the set point the corresponding bit is set in the Status Register 4 11 3 3 Status Register Mask Bit 3 Display Sensor Channel Change Enable If the Sensor Channel Change Bit 3 is selected the bit 3 in the Status Register is set when a channel change occurs 4 11 3 4 Status Register Bit 5 Overload Error Indicator Enable If the Overload Error Indicator Enable Bit 5 is set then if the display has an overload condition on any channel or an error occurs the cor
247. rument is equipped with a three conductor power cable which when plugged into an appro priate receptacle grounds the instrument 2 3 4 Bench Use The DRC 91C is shipped with plastic feet and a tilt stand installed and is ready for use as a bench instrument front of the in strument may be elevated for con venient operation and viewing by extending the tilt stand 2 3 5 Rack Mounting The DRC 91C can be installed in a standard 19 inch instrument rack by using the optional RM 3F or RM 3F H rack mounting kit A typical RM 3F H kit installation is shown in Figure 2 1 2 2 2 3 6 Sensor Input Connections The DRC 91C has two rear panel 5 pin input connectors for diode and resistance sensors The lead connection definition for the sen sor s is given in Table 2 2 and is shown in Figure 2 2 Figure 2 2 Sensor Connections gt E 4 4 Lead Sensor 4 Lead Hook up e g Germanium Carbon Glass Rhodium Iron 1 b 2 Lead Sensor 4 Lead Hook up e g Platinum Silicon Diode bj gt cr monzmo c 2 Lead Sensor 2 Lead Hook up Silicon Diode TT m COPYRIGHT 12 87 LSCI Model DRC 91C Connections for capacitance sensors and thermocouples are made through alternate connectors Refer to the appropriate input card section for sensor connectio
248. s leads to the TP24 CNT V and GND 2s found the calibration card of the controller Apply a zero signal to the V and Thermocouple Input terminals by shorting across the Terminal Block with a short jumper wire Allow the Terminal Block temperature to settle for five minutes Adjust the Rear Panel Offset Adjustment the Terminal Block until the output on the DVM is 0 0000 volt Be sure to remove the jumper wire after this step Apply 410 millivolt signal to the V and V Thermocouple Input terminals on the Terminal Block and allow the temperature to settle The DVM should read about 2 volts Adjust the input card trimpot labeled CNT V Control 9305 9 9305 Thermocouple Input Card Voltage Span until the output on the DVM is 2 000 volts 0 0001 volt 9305 9 3 Thermocouple and Secondary Sensor A D Calibration The Thermocouple and Secondary Sensor A D converters have an auto zero function which means that the only calibration required is for the relative gain span The procedure is as follows 1 Make sure the instrument is setup as described in parts 1 2a 2b and 3 the previous section Amplifier Calibration 2 Apply a 10 millivolt signal to the V Thermocouple Input terminals on the Terminal Block 3 The Display should read about 10 millivolts Adjust the trimpot labeled A D Thermocouple A D Span so that the voltage read on the Dispia
249. s and start the screws Carefully move any misaligned cards to their proper position and tighten the cover screws Replace the top panel and three panel screws 9305 4 SENSOR ATTACHMENT Thermocouple leads are attached to the Terminal Block by aluminum screws Be sure to tighten the terminal screws carefully Loose connections will result in unstable readings and control The leads must be connected with the proper polarity or the 29305 will not operate properly The positive terminal of the terminal block is marked with a plus sign and should correspond with the thermoelement listed for each type of thermocouple in Section 9305 5 9305 5 NOTES ON THERMOCOUPLES Lake Shore s 9305 Thermocouple Input Card supports the Chromel vs Gold E K and type thermocouples 9305 5 1 Gold Chromel Thermocouples The Gold Chromel thermocouple consists of Gold Au 0 03 or 0 07 at Iron Fe alloy as the negative thermoelement and a Ni Cr alloy Chromel as the positive thermoelement KP This type of thermocouple can be used at very low temperatures even below 10 K 9305 5 2 Type E Thermocouples The ASTM American Society for Testing and Materials designation type E indicates a thermocouple pair consisting of a Ni Cr alloy 9305 4 positive atmospheres Model DRC 91C 93C Chromel as the positive thermoelement and Cu Ni alloy Constantan as the negative thermoelement EN Th
250. s and typically has a value between 1 and 2 This expression for the IV characteristics of a p n junction is valid from approximately 40 K to above 300 K for the silicon diodes discussed here Below 40 K a new conduction mechanism becomes dominant suggesting the influence of impurity conduction carrier freezeout increased ohmic behavior of the bulk material and p i n diode type behavior The only adjustable parameter in Eq 1 which is necessary for the present analysis is the parameter n This parameter can be determined quite easily from the IV characteristics of the silicon diode temperature sensor The parameter ls is eliminated by normalizing the IV curve to an arbitrarily chosen point on the curve The value of n 1 8 was found to give a relatively good fit to the IV data for both 305 and 77 K and has been assumed in the present discussion 7 Equation 1 can now be solved for V I V I nkT e in I ls 1 2 Substituting a dc current with ac modulation lac lac cosaf the average voltage read by the voltmeter in the dc voltage mode can be calculated from 1 rr V l cos cat dt 3 where T the period of integration of the voltmeter or approximately 21 0 Implied in this derivation is the assumption that is sufficiently small so that effects from diode capacitance on the order of picofarads can be ignored On carrying out the integration of Eq 3 and subtracting V lac the dc offset volt
251. s reset to zero The practical realization of this circuit is an integrator inserted between the deviation amplifier and the power stage The origin of the interchangeable terms integral control and automatic reset is evident How does a proportional plus integral controller behave in a cryogenic system First in the idealized case let us again assume an infinite thermal conductivity which results in zero thermal resistance between the sensor and the heater The reset integrator continues to integrate until the error signal reaches zero which stops the integral action but keeps its output at the level corresponding to that needed by the power stage to overcome the droop This output is now the only drive to the power stage since the proportional error signal has been forced to zero No overshoot will occur since zero thermal resistance eliminates the thermal lag which is the cause of overshoot The zero thermal time constant also means that any amount of reset will eventually force the system to zero error Before we switch the discussion back to real systems let us deal with the nomenclature and units involved in integral control Automatic reset action can be expressed in terms of a time constant minutes or its inverse reset rate repeats per minute The reset time constant is the time required measured in minutes for the reset circuit to integrate to full output with an input signal which is constant and equal to the proportional band
252. s then determined from Table 3 4 the Curve Number to Position Number Correlation Table A complete discussion of curve selection is given in Section 3 9 and in particular Section 3 9 2 1 8229 6 REPLACEABLE PARTS Included in this Section is Figure 8229 1 It includes the Model 8229 Scanner Conversion Option schematic replaceable parts list and illustrated component layout Refer to the manual for ordering information 8229 3 105 321 105 322 106 250 106 142 106 424 104 524 RELAY DPST DRYREED 6 POST LOCKING RA PORT EXPANDER 104 210 RELAY DPST DRY REED CONNECTOR 26 PIN RA HEADER IC OC HEX INVERTER CR 3402 05 91 _ 7102 05 1010 57 30240 2420 09075 1061 609 2602MR 8255 5 _ 7406 7 6 E POSITION DATA POS 1 Pos e2 POS GND 82 y Ve v _ POS 1 POS e 3 POS 4 GND 1 I T I HOST UNIT P4 24 23 12 11 Ie 8 6 Eu E L4 213 14 22216 16 17 18 19 20 p P O J 24 22 23 21 16 2 6 WIRE J CABLE I INPUT CARD 2 S Yi ME 18412 D tub 0482 2
253. sistance range for the card an overload condition is present and is indicated by OL on the display The display ranges and resolutions for the 9220 P2 and 8219 2 9220 P3 and 8219 P3 and 9220 R1 and 8219 R1 are 0 00 to 299 99 ohms 0 0 to 2999 9 and 0 000 to 99 999 ohms respectively Again if a resistance exceeding full scale is applied to the input OL is indicated on the display Section III 3 8 5 5 Capacitance Units The capacitance mode is allowed for the 9215 Input Card which can be configured in the 15 or 150 con figurations The display range and resolution is 0 000 to 30 000 or 0 00 to 150 00 nanofarads respect ively An input in excess of the configured maximum is indicated by OL the display 3 8 6 Display Resolution The Model DRC 91C allows the user to set the display resolution over the range from 1 kelvin to i milli kelvin 9317C input card temperature is rounded to the least significant digit of the resolution range se lected Since the temperature display resolution is dependent on both the sensor units voltage resistance or capacitance resolu tion of the Input Card as well as the sensor sensitivity temperature resolution is greatly dependent on the sensor Refer to Table 3 1 for a representative summary of system resolution sensor plus instrument resolution versus sen sor sensitivity TABLE 3 1 Sensor Maximum Temperature Sensitivity Resolution in K Volta
254. st illustrated component layout Refer to the manual for ordering information 8223 7 REPLACEABLE PARTS LIST MODEL 8223 RS 232C INTERFACE OPTION LSCI Part Number 106 253 102 071 105 408 105 406 104 053 102 018 104 310 104 203 104 523 104 720 104 721 XSTR Description 0 25 PIN D STYLE PLUG GEN PURP NPN DIP SWITCH 8 POS DIP SWITCH 6 POS IC BAUD GENERATOR REGULATOR 12 IC 8 BIT MUX QUAD 2 INPUT NOR IC UART IC TRANSCEIVER IC TRANSCEIVER MFR PART NO DB 25s 255225 _ 76808 d 765806 MC14411 78112 DM8B1LS95AN 741502 P8251A 1488 _ MC1489NL 6 12 M c DATA TERMINAL READY amp 1 d Lal 992999922 OPTION SLOT 2 1 21 gt E Jind REQUEST TO SENO 3 44441 71 RGB Ld d od dod PE d Il b TRANSMITTED DATA TX RDY v5 P8281A ET i DATA SET READY gt cH neceweo Lite DET TIT 79 MOUNTS BACK INTERFACE CUTOUT H1 1 93 IS WITH HOOD TO 41 9 T Tits __ __ is ca E 4 741582 GND PINT 27 2015 12 14 Y1 E x Et 1 8432 4
255. subroutine for evaluating the temperature 7 from the Chebychev series using temperature 7 from the Chebychev series using Equations 1 and 3 An array should be Equations 1 and 4 Double precision calculations are dimensioned See text for details recommended Table 1 Chebychev Fit Coefficients 120Kto245K 245 1000 4100Kto4 5K VL 1 32412 VL 1 32412 VL 1 32412 VL 1 32412 VU 1 69812 VU 1 69812 VU 1 69812 VU 1 69812 A 0 7 556358 A 0 17 304227 A 0 71 818025 A 0 287 756797 53 799888 O OOO OOO W NO CO OD NM BW O ONO 0 014814 0 008789 0 008554 0 039255 0 015619 0 058580 A A A A A A A A A A WW n i 00 1 Application Notes 9 Lake Shore Cryotronics Inc DT 470 SERIES TEMPERATURE SENSORS INSTALLATION AND OPERATION There are three aspects of using a temperature sensor which are critical to its optimum performance The first involves the proper electrical and thermal installation of the connecting leads which run to the sensor while the second aspect is the actual mounting of the sensor to the sample assembly The final concern is the measurement electronics used for reading and recording temperature data from the sensor CONNECTING LEADS Although the majority of the DT 470 series sensors are
256. t cards from the DRC 81C or DRC 82C can be used in the DRC 91C Section VI The DRC 91C will cards if the dip switch settings are set correctly This Dip Switch is located in the rear right hand corner of the main board below the AC input connector recognize these WARNING lo prevent shock hazard turn off the instrument and discon nect it from the AC line power before changing the Input Card switch settings OLD INPUT CARD DIP SWITCH DEFINITIONS BIT O PS OG NEW CARD NON 8210 8211 OR 8219 CARD NON 8210 8211 OR 8219 ALSO COMBINATIONS OF A AND B BIT 7 1 ON OFF X DON T CARE SWITCHES 4 AND 8 ARE RESERVED COPYRIGHT 12 87 5 Model DRC 91C 93C 9210 Diode Input Card 9210 DIODE INPUT CARD OPTION 9210 1 INTRODUCTION This section contains information pertaining to the Model 9210 Diode Input Card Included description specifications installation operation and maintenance information 9210 2 DESCRIPTION The Model 9210 Diode Input Card is designed to be installed in a DRC 91C or DRC 93C to convert either the Input A or Input B or both with two options to accommodate diode sensors with a voltage output of up ta 3 0000 volts 9210 3 configuration The 9210 3 is used with Lake Shore DT 500 DRC DT 470 Series Sensors Cali
257. t is not a diode curve since the instrument is de faulting to the lowest number diode curve 00 Since the Heater display is not blank we know that the SENSOR ID switches are indicat ing position and not curve number The other possibility is that the REMOTE SENSOR ID is on position 7 3 10 6 Sensor Curve assignment to Sensor Position After selecting either the A or B input along with the selected posi tion from the SENSOR ID the REMOTE SENSOR ID or the position from the 8229 scanner option the curve number associated with the selected position number is changed by de pressing the LOCAL button for more than one second simultaneously with the or as desired to select the Sensor Curve The current curve number selected is displayed in the 3 10 Model DRC 91C Heater window with the default curve number shown in the display window along with selected posi tion Curves associated with positions 00 through 15 in Table 3 4 are changed as described above Curves sociated with positions 16 30 can only be changed over the 488 Bus see Section 4 16 7 3 11 CONTROL BLOCK 3 11 1 SET POINT change the Set Point numerical ly pressing the 4 or v key incre ments or decrements the least sig nificant digit pressing the 44 or vv key changes the third digit from the right and using the combination of the 44 and 4 keys or vv and v keys alters the fourth digit from the right If one of these keys
258. ted from the Setpoint voltage A signal which is 200 times the digital value as 9305 5 9305 Thermocouple Input Card calculated above is applied to the Setpoint D A to obtain the Setpoint voltage for control The control analog hardware compares the Setpoint voltage from the Setpoint D A converter and the amplified thermocouple voltage to obtain an error signal The error signal is minimized through the PID control circuitry 9305 7 OPERATING INSTRUCIIONS 9305 7 1 Selection Thermocouple Curve Thermocouple Tables are chosen by selecting one of the Curves numbers given in Table 9305 3 The instruments detect the presence of the Thermocouple Input Card and then select the proper Thermoccuple Table rather than the Standard Diode or Resistance curve listed in the Instruction Manual The SENSOR ID Switches on the rear panel of the DRC 91C are used to select curves as described in Instruction Manual Section 2 3 8 Curve selection can also be made over Computer Interface as described in Section 4 8 5 On the DRC 93C the Thermocouple Table is selected by selecting the Curve as described in the DRC 93C Instruction Manual Section 3 9 1 Curve selection can also be made over Computer Interface as described in Section 4 8 9 9305 7 2 Selection of Reference Junction Compensation on the DRC 91C Whether or not Reference Junction Compensation is used is selected using Switch 3 of the SENSOR ID When Switch 3 of the SEN
259. ter string The following program is for the HP86B and is an example of the XDT output SCIT for a unit with only Standard Curves 00 thru 05 present 10 REM Program to Output SCIT 20 DIM FILETABLES 321 OUTPUT 712 XDT Ask for 40 ENTER 712 FILETABLES Input SCIT 50 DISP FILETABLES 1 16 Bytes Free 60 DISP FILETABLE 17 38 Nxt Loc 70 DISP 39 56 Curve 00 80 DISP FILETABLES 57 74 Curve 01 90 DISP FILETABLE 75 92 Curve 02 100 DISP FILETABLES 93 110 Crv 03 COPYRIGHT 3 88 LSCI Section IV 110 DISP FILETABLES 111 128 Crv 04 110 DISP FILETABLE 129 152 A00 120 DISP FILETABLES 153 176 130 DISP FILETABLES 177 200 140 DISP FILETABLES 201 224 TO 150 DISP FILETABLES 225 248 B00 160 DISP FILETABLES 249 272 170 DISP FILETABLES 273 296 180 DISP FILETABLE 297 319 TO 190 END Note that the last character to be displayed is number 319 since the Terminators CR LF have to be input but not displayed This program results in the following output of the Sensor Curve Informa tion Table 3584 BYTES FREE 0200 IS NEXT LOCATION 00 31 1D40 DRC D 01 31 1DFO DRC E1 02 31 1EA0 CRV 10 03 31 1F50 DIN PT 04 31 2000 CRV 10 05 31 20B0 RESVRD 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 4 14 2 The XDN N gt C
260. ter and COPYRIGHT 12 87 LSCI Section III III INSTRUCTIONS a resistance thermometer can be used on the two inputs Another possibility with the 9318C and 9220 Options would be the presence of a GR 200A Series Germanium Sensor as well as a PT 100 Series Platinum Resistance Sensor Both inputs are updated independently which allows them both to be queried under IEEE 488 RS 232C control dependent of which input is dis played The addition of the 8229 Sensor Scanner Option adds capability for 4 additional inputs to the A chan nel resulting in up to 5 sensors of the same type being allowed on inputs A Al A2 A3 and A4 3 2 4 Old Version Input Cards The 8210 8211 diode input cards can be used in the 91C as well as the 8219 series resistance input card The installation of these cards is covered in Section VI of this manual Note that there are Dip Switch settings on the main board which must be set in order for these older cards to work pro perly 3 3 CURVE ENTRY The DRC 91C allows the user to enter his own sensor calibration over the remote interface Section IV of the manual covers entry over the IEEE 488 or RS 232C inter faces Ihe curve is stored in a battery back up non volatile RAM NOVRAM which be read wrote to an unlimited number of times and that the number of data points stored per curve can be any where between 2 and 99 two being the lower limit which defines a straight
261. terface XR amp I function was performed the unit displays the error stores it in the WS data location and waits for the NOVRAM initialization sequence to be performed Repeated ErrO2 conditions could signal a failure by the NOVRAM to retain data and it should be replaced The REMOTE SENSOR ID for the unit allows for an input range of 00 00000 on bits B4 thru BO of the ID to iF 11111 on bits B4 thru BO The 1F input is reversed for a REMOTE SENSOR ID error condition the Position Data Adaptor uses this code to indicate that more than one Sensor Scanner is active to the unit When the error stores it in the WS data location and continues to monitor the REMOTE SENSOR ID until the fault is corrected 8223 RS 232C Interface Parity Error The error may be caused by problems with the signal lines or incorrectly specified parity The error and any of the other DRC91 RS errors is transmitted when the unit is asked to output and ls cleared following the first transmission after the error Possible Cause Corrective Action 8223 RS 232C Interface Overrun Error The error is caused by the unit s main processor not reading the input character before the next one becomes available The overrun character s are lost 8223 RS 232C Interface Framing Error The error may be caused by signal line transients or incorrectly specified stop bits or character length 8223 RS 232C Interface Input Buffer Overrun Error The error occurs
262. th Local Lockout Changes terminating characters when IEEE Address Switch 1 is CLOSED 1 Forms of the command are TO Tl T2 and T3 When is Terminators are P ENDE LF also with Switch OPEN LF END CR default unless changed LF Clear command returns unit to power up state Restart kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Request Functional Description Interface Status ZN MN5 TN 8 Characters plus up to 2 Terminators where is EOI status is Mode status is Terminator status Input and Option Card Data A C4C5C3C4C5C6C B CgC9C10C11C12C13C14 1 5 16 17 1 8 2 lt 19 20 21 622 3 23 24 25 lt 26 40 Characters plus up to 2 Terminators where is the A Input Card 4 is the B Input Card 15 18 is the Option 1 Present 19 22 is the Option 2 Present C237C26 is the Option 3 Present corresponds to a numeric value 0 9 b The AND symbol is used to indicate messages sent concurrently C END EOI d DAB last data byte e corresponds to an alphanumeric 0 F COPYRIGHT 3 88 LSCI 4 9 Section IV 4 7 2 2 Remote The DRC 91C is the local front panel mode when first turned remote message 1 see Table 4 6 allows the 91C to be controlled over the IEEE 488 inter face In Remote the front panel controls are disabled except the LOCAL button and are
263. the sensor serial no The 18 characters must be immediately followed by a comma The data is input in units temperature pairs with the units in the form of Voltage LogR Data points must be entered in ascending units order The character terminates the Sensor Curve input XCN1N5 C1 X XXXXX TTT T Edit Sensor Curve point is either inserted in its proper position in the curve or it is added to gt j X XXXXX TTT T the curve as a new data point XKN4N5 Erases kills Sensor Curve N4N5 and repacks all curve data Standard Curves 00 thru 05 cannot be erased XR amp I Command sent five times will delete all Precision Options and any curves stored in unit by user Assignment of Curve 4 to Position in Correlation Tables 182 Assign the Input A or Input B Remote Position 2 to XBCiC59 N4N5 Sensor Curve number NjN5 2 is the Remote Position 00 thru is the Sensor Curve number 00 thru 31 This Command modifies the Remote Position to Sensor Curve Correlation Table 3 3 and XDT output data NOTE The added to the end of the 2 XCNQ4N5 XENjN5 commands is required for the command to operate properly Due to the length of some of the data strings appropriate computer time outs must be allowed when performing these functions If a hardware problem is detecte
264. then control lable over the IEEE Bus The instrument s initial set up is determined by the front panel settings at the time when the instrument is placed into Remote The DRC 91C may also be placed into remote by pressing the REMOTE button on the front panel or ad dressed to talk by the BUS CON TROLLER 4 7 2 3 Local Lockout This message M2 Table 4 6 disables the DRC 91 Local Front Panel controls including the LOCAL button The message is in effect until the message is cleared over the Bus or power is cycled Many IEEE 488 cards for IBM PC s automatically place addressed instruments into Local Lockout To be able to place the DRC 91C into Remote without Local Lockout the user may need to reconfigure his IEEE 488 card 4 7 3 Terminating Characters The TN Command Terminating characters TO 2 and T3 Table 4 6 are used to indicate the end of a record Record terminators are used when the unit has completed its message transfer Switch 1 of the IEEE address defines the terminator status If switch 1 is OPEN 0 the terminator status is defined as TO CR LF and terminator status can not be changed over the interface When switch 1 is CLOSED 1 the terminator status is defined as Ti LF CR and the status can be changed using the TO T1 T2 or commands 4 10 Model DRC 91C 4 7 4 Clear The C lear Message see Table 4 6 sets the DRC 91C to the turn on st
265. thermal value is used until the correction criteria is met and the thermal updated again If the active 9317C 9318C 6 CALIBRATION SCHEDULE AND EQUIPMENT The design of the 9317C 9318C Resistance Input Card is such that re calibration should not required more often than every six to twelve months in order to keep the card within its accuracy specification However if re calibration is required the following equipment is needed to re calibrate the card 1 Digital Voltmeter DVM 5 1 2 digit resolution or better 2 Five 5 Precision Standard Resistors which are accurate in value to at least 0 01 Their values in ohms must be 9317C 1 10 100 1K 10K 9318C 10 100 1K 10K 100K 3 Precision Voltage Standard capable of a plus and minus 10 millivolt signal to within 0 1 microvolt 9317C 9318C 5 9317C 9318C Input Cards Since very often these values will not be available to the user of this instrument Lake Shore Cryotronics Inc offers a calibration service Contact a factory representative for informa tion concerning re calibration Note that the card believes that the correct resistance and voltage is applied during calibration therefore the accuracy of the calibration depends on the accuracy of the standards used 9317C 9318C 7 CALIBRATION The 91C 93C should be allowed a one hour warm up time to achieve rated specifications References are made in the calibration pro
266. thode by referring to the accompanying device drawings Be sure that the lead identification remains clear even after installation of the sensor and record the serial number and location The procedure used to solder the connecting leads to the sensor leads is not very critical and there is very little danger in overheating the sensor If for some reason the leads have to be cut short they should be heat sunk with a copper clip or needle nose pliers before soldering Standard rosin core electronic solder m p 180 C is suitable for most applications Applications involving the use of the SD package up to 200 C will require a higher melting point solder A 90 Pb 10 Sn solder has been used quite successfully with a rosin flux For all adapters except the CY CU DI the leads are a gold plated Kovar Prolonged soldering times may cause the solder to creep up the gold plated leads as the solder and gold alloy This is not detrimental to the device performance When installing the sensor make sure there are no shorts or leakage resistance between the leads or between the leads and ground GE 7031 varnish or epoxy may soften varnish type insulations so that high resistance shunts appear between wires if sufficient time for curing is not allowed Teflon spaghetti tubing is useful for sliding over bare leads when the possibility of shorting exists Also avoid putting stress on the device leads and allow for the contractions that occur during coo
267. to as low as 1 K with reproducibilities to better than 50 mK Figure 1 shows the voltage variation with temperature for a typical silicon diode temperature sensor An error arises in diode thermometry if the excitation current is not a true dc current but has an ac component superimposed on the dc Although the ac component can be due to a poorly designed current supply a more common source of the ac is noise induced in the measurement circuit This noise can be introduced through improper shielding improper electrical grounds or ground loops Currently available voltmeters have sufficient normal mode rejection capabilities in their dc measurement modes that these noise effects can go completely unnoticed if they are not explicitly checked The equivalent temperature error which may be caused by this problem is typically a few tenths of a kelvin although an extreme case with a 4 K error has been observed The effect of the ac noise appears as a shift in the dc voltage measurement due to the nonlinear current voltage characteristics of the diode An illustration of this effect is shown in Fig 2 where an exaggerated IV curve is given An induced ac noise current superimposed on the dc operating current lac is shown along the current axis The resulting voltage seen by the voltmeter is shown along the voltage axis The nonlinear IV characteristics of the diode have caused a distortion in the ac voltage signal making it asymmetrical with
268. ts Repeated mounting and demounting of a soldered sensor may eventually cause wetting deterioration and ruin the thermal contact to the sensing element although the nickel buffer layer should minimize these problems CAUTION The preferred method for mounting the SD sensor is either the CO adapter or bonding with epoxy Lake Shore Cryotronics Inc will not warranty replace any device damaged by a user designed clamp or damaged through solder mounting DT 470 LR 3 2 12 19 The gold plated copper LR adapter is designed for insertion into 1 8 inch diameter hole A thin layer of Apiezon N Grease should be applied to the copper adapter Anode before insertion This eases installation at room temperature and enhances the thermal contact 3 1 mm dia Cathode DT 470 CU DT 470 DI DT 470 CY The gold plated copper CU DI and CY 2 9 mm diameter 14 3 mm dia adapters serve as both sensor and thermal 0 76 mm off center anchor assembly These adapters mount to a flat surface with 4 40 brass screw Avoid over tightening the screw use only enough force to firmly hold the sensor in place A brass screw is recommended as the differential thermal contraction between the 3 8 mm 8mm 2 9mm dia hole adapter and the screw causes the mounting thick diameter 5 1 mm centered assembly to tighten as opposed to loosen thick when the system cools Apply a thin layer of Apiezon N Grease to enhance thermal contact DT 470
269. tting the RESET Integral The I Command 4 16 4 9 5 Setting the RATE Derivative The D Command 4 16 4 9 6 Heater Range The Command s s e s e 4 16 4 9 7 NOTE The Return to Local 4 16 4 9 8 The Data String 4 16 4 10 THE SCANNER INPUT CARD P Ae de 4 16 4 10 1 SCAN Programming Instructions WS 4 16 4 10 2 Setting the Dwell Time The YAN NoN3 and YBONAN4 Commands 4 16 4 10 3 Selecting the Scanner Channel The Command E d 4 16 4 10 4 Enabling the Scan Function The YS Command ewe 4 16 4 10 5 Holding the Scan Function Command 4 17 4 10 6 The Data String o 4 17 12 87 TABLE CONTENTS cont td 4 11 THE SERVICE REQUEST STATUS REGISTER STATUS REPORTS AND THE STATUS REGISTER MASK T 4 17 4 11 1 The Service Request E del ee 4 18 4 11 2 Status Register and Status Reports e 4 18 4 11 2 1 Status Reports 0 and 1 Display and Control Data Ready 4 18 4 11 2 2 Status Report 2 The Control Channel Limit 4 18 4 11 2 3 Status Report 3 Display Sensor Channel Change 4 19 4 11 2 4 Status Report 5 Overload Error Indicator 4 19 4 11 2 5 When operating without the Service Request 4 19 4 11 3 The Status Register Mask The Command 4 19 4 11 3 1 Status Register Mas
270. tween the block and the sensor and heater The result will be that the temperature within the block will be isothermal no matter at what rate the block is heated or cooled For the following discussion ignore any noise associated with the system and assume that to control at 20 kelvin the heating power required is 0 2 watts Assume also that 50 watts of heater power is available reducible in five steps of one decade each Figure 5 shows the control offset for 1 6 1 6 0 32 0 an amplifier gain of 100 and three output power settings which will 0 1 deliver enough power to the system to balance the cooling power FIGURE 5 Effect of output power setting on offset for a The temperature offsets for a power level of 0 2 watts at 20 kelvin proportional controller only are easily calculated from Figures 2 and 4 for the three maximum power settings 0 1 K for a 50 watt setting 0 32 for a 5 watt setting and 1 0 for the 0 5 watt setting As expected the temperature offsets become smaller as the loop gain increases However there are limits to this approach as we move from the idealized example to a real system The Real World Unfortunately the thermal conductivity within a system is not infinite and both it and the heat capacity may vary by several orders of magnitude between 1 K and 300 K Also the controller the sensor the sensor leads and the block may all have electrical noise This noise is ampl
271. two lead devices measurements should preferably be made using a four wire configuration to avoid all uncertainties associated with the lead resistance This is done by using four connecting leads to the device and connecting the V and leads to the anode and the V and leads to the cathode as shown in Figure 1 The exact point at which the connecting leads are soldered to the device leads results in negligible temperature measurement uncertainties In a two wire measurement configuration the voltage connections point A in Figure 1 are made near or at the current source so only two leads are actually connected to the device Some loss in accuracy can be expected since the voltage measured at the voltmeter is the sum of the diode voltage and the voltage drop across the connecting leads The exact temperature uncertainty will depend on the temperature range and lead resistance For a 10 ohm lead resistance the diode voltage will be offset by 0 1 mV which gives a negligible temperature error at liquid helium temperature but a 50 error near liquid nitrogen temperature Note the DI and CY adapter can be used only in a two wire configuration An excessive heat flow through the connecting leads to any temperature sensor can create a situation where the active sensing element for the DT 470 this is the diode chip is at a different temperature than the sample to which the sensor is mounted This is then reflected as a real temperature offset between wh
272. uirements Model DRC 91C SECTION 4 1 IEEE 488 INTERFACE The IEEE 488 INTERFACE is an in strumentation bus with hardware and programming standards designed to simplify instrument interfacing The IEFE 488 INTERFACE of the DRC 91C fully complies with the IEEE 488 1978 standard and incor porates the functional electrical and mechanical specifications of the standard It also follows the supplement to that standard titled Code and Format Conventions for use with IEEE Standard 488 1978 This section contains general bus information Model DRC 91C interface capabilities addressing and the programming instructions that control the DRC 91C functions 4 2 GENERAL 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 Standard 488 1978 publication IEEE Standard Digital Interface for Programmable Instrumentation All instruments on the interface bus must be able to perform one or more of the interface functions of TALKER LISTENER or BUS CONTROLLER A TALKER transmits data onto the bus to other devices A LISTENER receives data from other devices through the bus The BUS CONTROLLER designates to the devices on the bus which function to perform The DRC 91C performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is your Dig
273. usage and several quick tests are outlined to verify whether or not a noise problem exists Experimental data and derivations from theoretical p n junction characteristics are given which correlate the ac noise level with possible voltage temperature measurement errors These results can be used in estimating the accuracy and performance of a temperature measurement system Several of the more common problems which introduce noise into diode circuitry are described INTRODUCTION Current technological uses of temperature sensors require better calibration accuracies and better device performance than ever before However the assurance of an accurate temperature measurement does not stop with simply the sensor specifications Just as critical is the instrumentation used with the sensor and the manner in which the instrumentation is used This paper concentrates on identifying verifying and eliminating an often overlooked instrumentation or system induced error in the use of diode temperature sensors PROBLEM DEFINITION Semiconductor diode temperature sensors have been in use for over 20 years and with the advantages they offer over resistance sensors or thermocouples for many applications their popularity continues to increase Diodes are operated at a constant current typically 1 10 or 100 pA while the voltage variation with temperature V T is monitored The diode sensor has a useful temperature range from above room temperature
274. used The controllers are designed to operate on sensor curve data in the range of 0 00000 to 3 00000 volts so thermocouple voltage must be converted to this range before it is entered into a curve table obtain the proper table vaiue from a thermocouple voltage it must be summed with 15 millivolts to make it positive and multiplied by one hundred to shift resolution 100 VTHERMOCOUPLE mV 15 mV 15 0000 millivolt thermocouple voltage will result in a 0 00000 volt table value 15 0000 millivolts will result in 3 00000 volts Once the Thermocouple Curve has been converted carefully read and follow the instructions in DRC 91C Manual Section 4 14 or DRC 93C Manual Section 4 16 on how to enter the data into a controller 9305 8 EQUIPMENT CALIBRATION SCHEDULE AND The design of the 9305 Thermocouple Input Card is such that calibration should not be required more often than every six to twelve months in order to keep the card within its accuracy specification However if calibration is required the following equipment is needed 9305 8 Model DRC 91C 93C 1 Digital Voltmeter DVM 5 1 2 digit resolution or better 2 Precision Voltage Standard capable of a 10 millivolt signal to within 1 microvolt The accuracy of the calibration depends on the accuracy of the Digital Voltmeter DVM and the Voltage Standards used Since very often these values will not he avai
275. ut and set the standard to 0 0000 volts Adjust the trimpot marked 2 the calibration cover until the DVM reads as close to 0 volts as possible Set the standard to 0 2500 volts and adjust the trimpot marked S the calibration cover until the voltage reads 2 5000 volts 4 Calibrate the A D Converter Verify that the Display Sensor is the desired Input Card and that the units are ohms Set the standard to 0 2700 volts and adjust the trimpot marked A D until the display reads 270 00 ohms for the 9220 P3 an input of 0 2700 volts results in a display of 2700 0 ohms and for the 9220 R1 an input of 0 2700 volts results in a display of 81 00 chms Check linearity by inputting 0 2000 and 0 1000 volts and verify that the unit displays 200 00 and 100 00 ohms within 0 01 ohms equivalent for the 9220 P3 and 9220 R1 5 Install the top panel 9220 7 SENSOR CURVE INFORMATION Sensor Curve data for use with the 9220 RTD Configurations must be put in table form consisting of voltage and temperature points with the voltage in ascending voltage order Since the 9220 raw data would be in resistance form it must be converted prior to entering Refer to Section 4 of this manual for a discussion of how the data must be converted and formatted for entry into the unit over the remote interface and to Appendix B for a discussion of Precision Option curves and examples of curves that would be used with the
276. when more than 256 characters are input to the FIFO buffer of the unit Any characters received after the 256th character are lost Input Overload When an input signal which exceeds the maximum allowed for that input is applied the error occurs When the error occurs the displays OL if it is the DISPLAY SENSOR input and stores OL in either the WS and or WC data locations 8217 8218 Input Card Error 8217C and 8218C Input Cards have an EEPROM that stores the calibration constants used to set the sensor current and determine the resulting voltage accurately When the card detects an error in the EEPROM storage it tries to correct it If it cannot correct the error it transmits the Err20 code to the main processor and resets the sensor current to the lowest value to avoid any potential sensor damage The unit displays the error stores it in the WS data location and halts operation The Input Card calibration procedure should be preformed to try to correct the problem If the error code still exists the Input Card EEPROM needs to be replaced C 2 COPYRIGHT 5 88 Possible Cause Corrective Action Unrecognized A Input Card type The 92xx Series cards and Smart microprocessor controlled Input Cards tell the main processor what card type they transmitted the error could be caused by the Input Card not being present or if the card had a selection switch de selected for example if it were not pressed correctly or came out of
277. wo calculation methods are in even better agreement and a plot similar to Fig 4 would show no difference The details of the extended calculation have not been given as the mathematics is somewhat tedious and the slight discrepancies between the small signal model and the extended model do not justify the added complexity For all practical purposes Eq 6 can be reliably used above 40 The physics of a p n junction at 4 2 K is not clearly understood and attempts to correlate the present data by modeling low temperature IV characteristic of a diode failed If the diode does take on a p i n type behavior the different curves shown in Fig 5 for 1 10 and 100 pA can possibly be understood in terms of the additional current dependent terms in the IV curve 6 Another explanation for the significant offset voltage at 100 pA could be self heating in the diode If the diode is operated at too high a power level the diode has a tendency to warm slightly above the surrounding environment This will have the effect of distorting the IV curve in the direction of lower voltages at higher currents This distortion will then increase the offset voltage At 4 2 K self Heating usually becomes a problem as the current approaches 100 Application Notes T 77K loc 10 uA AV uV 1 kHz 20 kHz 0 1 2 3 4 5 6 7 8 RMS AC VOLTAGE mV FIGURE 6 DC offset voltage as a function of rms ac voltage across a silicon diode temperature sensor o
278. work on the card so that when the sensor signal is reversed for thermal correction while controll ing the correct polarity of the control signal is maintained 9317C 9318C 5 1 Thermal Correction Selection for the DRC 91C The control thermal correction function is enabled or disabled using switch 3 of the appropriate SENSOR ID located on the rear panel of the DRC 91C 9317C 9318C 3 9317C 9318C Input Cards When switch 3 of the SENSOR ID is CLOSED ON the thermal correction is enabled When switch 3 is OPEN OFF the thermal correction is disabled Pressing the IOCAL key for the appropriate channel will display either 18 C or 17 C plus that the control thermal correction is enabled The minus means the control thermal correction is disabled 9317C 9318C 5 2 Thermal Correction Selection for the DRC 93C When a 9317C or 9318C Resistance Input Card is installed pressing the SENSOR key will display either 9317C or 9318C for the appro priate channel plus means the control thermal correction is enabled The minus means the control thermal correction is disabled Enable disable the control thermal correction from the front panel by using a combination of the SENSOR SCAN 1 1 44 and keys as follows 1 Press and hold the SENSOR key 2 While holding the SENSOR key press the SCAN 1 key The SENSOR key may released 3 To change the sign change
279. y is 10 000 millivolts 4 This test is to verify that the A D converter is symmetrical Apply a 10 millivolt signal to the V and V Thermocouple Input terminals The DVM should read 2 0000 0 0006 volt The Display should read 10 000 0 003 If it does not meet these specifications the unit should be returned to the factory for calibration 9305 9 4 Reference Junction Test This test is to verify that the Reference Junction Compensation circuitry is operating properly If this test does not produce the following results please consult the factory 1 Apply a zero volt signal to the 9305 10 Control Model DRC 91C 93C and V Thermocouple Input terminals by shorting across the Terminai Block with a short jumper wire 2 Select the controller to display the 9305 card in temperature units 3 Enable the Reference Junction Compensation as described in Section 9305 6 The reading on the display should read Room Temperature 4 Disable the Reference Junction Compensation and the display should read Zero degrees Celcius the normalization point of the curves 9305 9 4 Calibration Completion 1 Close 1 51 1 to return the 9305 to normal Secondary Sensor update operation 2 Remove anything that may be shorting the two halves of the terminal block 3 Verify that thermal correction is properly selected 4 Slide the top cover onto the instrument and replace the three screws 9305 10 OPT

Model DRC-91C - Lake Shore Cryotronics, Inc.

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