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1. W ju A wi mijo WOON AA Aja mui O D Jia j lt x z lt je jo jajo N y rin lt ix E lt ciAjojajojo u lolololololololo olololo lolololo H olo o o olo lolo g lol o o o Jo s o Jo Jol o 3 3 x gt lo Io ajo o jaa o Olzlz r ixic nHiiio AMO w pP mal yu lAl Ei mii m American Wire Gage AWG Wiring sizes are defined as diameters in inches and millimeters as follows AWG Dia In Dia mm AWG Dia In Dia mm AWG Dia In Dia mm AWG Dia In Dia mm 1 0 2893 7 348 11 0 0907 2 304 21 0 0285 0 7230 31 0 0089 0 2268 2 0 2576 6 544 12 0 0808 2 053 22 0 0253 0 6438 32 0 0080 0 2019 3 0 2294 5 827 13 0 0720 1 829 23 0 0226 0 5733 33 0 00708 0 178 4 0 2043 5 189 14 0 0641 1 628 24 0 0207 0 5106 34 0 00630 0 152 5 0 1819 4 621 15 0 0571 1 450 25 0 0179 0 4547 35 0 00561 0 138 6 0 1620 4 115 16 0 0508 1 291 26 0 0159 0 4049 36 0 00500 0 127 7 0 1443 3 665 17 0 0453 1 150 27 0 0142 0 3606 37 0 00445 0 1131 8 0 1285 3 264 18 0 0403 1 024 28 0 0126 0 3211 38 0 00397 0 1007 9 0 1144 2 906 19 0 0359 0 9116 29 0 0113 0 2859 39 0 00353 0 08969 10 0 1019 2 588 20 0 0338 0 8118 30 0 0100 0 2546 40 0 00314 0 07987 ambient temperature The temperature of the surrounding medium such as gas or liquid which comes into contact with the apparatus ampere T
2. Use the numeric keypad to enter the 3 digit lock code The keypad locks and the normal display appears Changes attempted to any parameters result in a brief display of the LOCKED message To unlock the keypad press and hold the Enter key for 10 seconds to display the screen shown as follows Use the numeric keypad to enter the 3 digit lock code The keypad unlocks and the normal display again appears All Model 331 parameters are now accessible 4 34 Operation 4 18 4 19 4 20 Lake Shore Model 331 Temperature Controller User s Manual DISPLAY BRIGHTNESS The user is able to control the brightness of the vacuum fluorescent display Press and hold the Display Format key for several seconds until you see the following display With ar Use the A or Y key to select 25 50 75 or 100 Press the Enter key The instrument returns to the normal display CAUTION Prolonged use of the display brightness on the 100 setting will reduce the life of the vacuum fluorescent display REMOTE LOCAL Local refers to operating the Model 331 from the front panel Remote refers to operating the controller via the IEEE 488 Interface They keypad is disabled during remote operation The mode of operation can be changed by pressing the Remote Local key When in the Local mode the Remote LED in the upper right hand corner of the front panel will be Off When in the Remote mode t
3. mar we The Integral I value is entered using the numeric keypad which includes the numbers 0 9 and decimal point Integral has a range of 0 1 to 1000 with a default of 20 Press the Enter key to accept the new setting You will see the next display The Derivative D value is entered using the numeric keypad which includes the numbers 0 9 and decimal point Derivative has a range of 0 to 200 percent with a default of 0 Press the Enter key to accept the new setting You will see the next display The MHP Output setting is entered using the numeric keypad which includes the numbers 0 9 and decimal point Manual heater has a range of 0 001 to 100 percent with a default of 0 Press the Enter key to accept the new heater setting Assuming the zone is controlling using Loop 1 you will see the next display Use the A or Y key to select the Heater Range High Medium Low or Off Press the Enter key to accept the new heater range and return to the normal display If you are controlling using Loop 2 the last heater range setting is omitted This completes the setting of Zone 01 Repeat the process for the subsequent zones 4 20 Operation Lake Shore Model 331 Temperature Controller User s Manual Zone Setting WorkSheet Zone 10 Seto int Proportional Integral Derivative MHP Output Heater Rance 0 1 1000 0 1 1000 0 200 0 100 g Off Lo
4. DO UL 4 26 Operation Lake Shore Model 331 Temperature Controller User s Manual Linear Continued 4 14 3 Use the A or Y key to toggle between the Linear B Variable SP1 SP1 SP2 SP2 Value Press the Enter key to accept the new setting You will see the next display sanar The Linear Variable B is entered using the numeric keypad which includes the numbers 0 9 and decimal point Press the Enter key to accept the new setting Press the Escape key to return to the normal display or continue with the Filter settings Paragraph 4 14 3 Filter The reading filter applies exponential smoothing to the sensor input readings If the filter is turned on for a sensor input all reading values for that input are filtered The filter is a running average so it does not change the update rate of an input Filtered readings are not used for control functions but they are used for all input features including Max Min The number of filter points determines how much smoothing is done One filter point corresponds to one new reading on that input A larger number of points does more smoothing but also slows the instruments response to real changes in temperature The default number of filter points is 8 which settles in approximately 50 readings or 5 seconds The filter window is a limit for restarting the filter If a single reading is different from the filter value by more than the limit the ins
5. 4 16 2 Analog Output In Manual Mode In Manual mode the analog output provide a fixed output according to a percentage of full scale entered by the user 100 00 to 100 00 corresponding to 10 V to 10 V The setting resolution on the display is 0 001 but the output itself is limited to 0 003 Press the Analog Output key Press the A or Y key to toggle between Bipolar Mode On or Off Bipolar mode refers to whether or not negative voltages are used as shown below 100 User Entry 0 100 Bipolar Mode On 10 V Output OV 10 V Manual Mode 0 User Entry 100 Bipolar Mode Off OV Output 10 V For this example we will choose Bipolar Mode On Press the Enter key The desired fixed output you want as a percent of full scale is entered using the numeric keypad which includes the numbers 0 9 and decimal point For this example we will enter 50 Press the Enter key The instrument will return to the normal display The analog output will begin to output a constant voltage that is 50 x 10 volts 5 volts In a second example if you repeat the same procedure using all the same settings but enter 75 then the output would be 75 x 10 volts 7 5 volts In a third example if you repeat the same procedure but choose Bipolar Off enter 25 then the output would be 25 x 10 volts 2 5 volts The difference being that any negative sign will be ignored with Bipolar
6. 128 64 32 16 8 4 2 1 Bit Name Bits 2 and 6 are not used The bus controller will only be interrupted with the reports of this register if the bits have been enabled in the Standard Event Status Enable Register and if bit 5 of the Service Request Enable Register has been set The Standard Event Status Enable Register allows the user to enable any of the Standard Event Status Register reports The Standard Event Status Enable command kESE sets the Standard Event Status Enable Register bits If a bit of this register is set then that function is enabled To set a bit send the command ESE with the bit weighting for each bit you want to be set added together See the ESE command discussion for further details 6 4 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Standard Event Status Register and Standard Event Status Enable Register Continued 6 1 4 1 The Standard Event Status Enable Query ESE reads the Standard Event Status Enable Register ESR reads the Standard Event Status Register Once this register has been read all of the bits are reset to zero Power On PON Bit 7 This bit is set to indicate an instrument off on transition Command Error CME Bit 5 This bit is set if a command error has been detected since the last reading This means that the instrument could not interpret the command due to a syntax error an unrecognized header unrecognized te
7. 222 00 151 28 6935 670 00 44 9 257090 54 00 98 2 610520 226 50 152 30 1761 688 50 45 9 216690 56 00 99 2 343820 231 50 153 31 8242 709 00 46 9 175140 58 00 100 2 073770 236 50 154 33 7187 732 50 47 9 132450 60 00 101 1 800570 241 50 155 36 1028 762 00 48 9 088620 62 00 102 1 524210 246 50 156 41 8502 833 00 49 9 043710 64 00 103 1 244740 251 50 157 44 2747 863 00 50 8 997710 66 00 104 0 962207 256 50 158 46 2907 888 00 51 8 950650 68 00 105 0 676647 261 50 159 48 1007 910 50 52 8 902530 70 00 106 0 359204 267 00 160 49 8256 932 00 53 8 840980 72 50 107 0 009079 273 00 161 51 5056 953 00 54 8 777760 75 00 108 0 344505 279 00 Curve Tables D 7 Lake Shore Model 331 Temperature Controller User s Manual Table D 9 Type T Copper vs Copper Nickel Thermocouple Curve Break Break point mV Temp K point mV Temp K point mV Temp K 1 6 257510 3 15 56 5 424100 84 00 111 0 623032 289 00 2 6 257060 3 56 57 5 380600 86 50 112 0 843856 294 50 3 6 256520 4 00 58 5 336260 89 00 113 1 067190 300 00 4 6 255810 4 50 59 5 291080 91 50 114 1 293090 305 50 5 6 254950 5 04 60 5 245070 94 00 115 1 521570 311 00 6 6 253920 5 62 61 5 188800 97 00 116 1 752660 316 50 7 6 252780 6 20 62 5 131290 100 00 117 1 986340 322 00 8 6 251380 6 85 63 5 072630 103 00 118 2 222600 327 50 9 6 249730 7 55 64 5 012780 106 00 119 2 461410 333 00 10 6 247810 8 30 65 4 951770 109 00 120 2 702740 338 50 1
8. C V mV Q Temperature sensor units max min and linear equation All readings twice per second 0 001 between 0 99 999 0 01 between 100 999 99 0 1 above 1000 Sensor dependent to 5 digits Setpoint Heater Range and Heater Output user selected Same as display resolution actual resolution is sensor dependent Numeric display in percent of full scale for power or current 1 Control Input Remote Alarm Tuning Ramp Max Min Linear 20 full travel keys numeric and specific functions Front panel curve entry display brightness control keypad lock out IEEE 488 2 Interface Model 331S Only Features Reading Rate Software Support Serial Interface Electrical Format Max Baud Rate Connector Reading Rate Special Interface Features Alarms Number Data Source Settings Actuators Relays Model 331S Only Number Contacts Contact Rating Operation Connector SH1 AH1 T5 L4 SR1 RL1 PP0 DC1 DT0 C0 E1 To 10 readings per second on each input LabView Driver RS 232C 9600 Baud DE 9 To 10 readings per second on each input at 9600 Baud Model 330 command emulation mode 4 High and Low for each input Temperature Sensor Units Linear Equation Source High amp Low Setpoint Deadband Latching or Non Latching Audible On Off Display annunciator beeper relays 2 Normally Open NO Normally Closed NC and Common COM 30 VDC at5A Activate relays on high low or both alarms
9. NTC RTD Reversal Off 13 NTC RTD Reversal On lt value gt Zero offset calibration constant value Remarks Provides the zero offset calibration constant for the selected input or analog output CALZ Zero Offset Calibration Constant Query Input CALZ lt input gt lt type gt term Format a nn lt input gt A B or V lt type gt 0 7or10 13 Returned lt value gt term Format nnnnnnn Refer to command for description Service 8 17 Lake Shore Model 331 Temperature Controller User s Manual This Page Intentionally Left Blank 8 18 Service Lake Shore Model 331 Temperature Controller User s Manual APPENDIX A GLOSSARY OF TERMINOLOGY absolute zero The temperature of 273 16 C or 459 69 F or O K thought to be the temperature at which molecular motion vanishes and a body would have no heat energy accuracy The degree of correctness with which a measured value agrees with the true value electronic accuracy The accuracy of an instrument independent of the sensor sensor accuracy The accuracy of a temperature sensor and its associated calibration or its ability to match a standard curve Alumel An aluminum nickel alloy which comprises the negative lead of a Type K thermocouple American Standard Code for Information Exchange ACSII A standard code used in data transmission in which 128 numerals letters symbols and special control codes are represented by a 7 bit binary number as follows
10. One point SoftCal calibrations for applications under 30 K are performed at liquid helium 4 2 K temperature Accuracy for the DT 470 SD 13 diode is 0 5 K from 2 K to lt 30 K with no accuracy change above 30 K Two point SoftCal calibrations for applications above 30 K are performed at liquid nitrogen 77 35 K and room temperature 305 K Accuracy for the DT 470 SD 13 diode sensor is as follows 1 0K 2K to lt 30 K no change below 30 K 0 25K 30K to lt 60K 0 15K 60K to lt 345 K 0 25K 345K to lt 375 K 41 0K 375to475K Three point SoftCal calibrations are performed at liquid helium 4 2 K liquid nitrogen 77 35 K and room temperature 305 K Accuracy for the DT 470 SD 13 diode sensor is as follows 40 5K 2K to lt 30 0 25K 30K to lt 60K 0 15K 60K to lt 345 K 0 25K 345 K to lt 375 K 41 0K 375to475K 5 8 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual SoftCal With Platinum Sensors The platinum sensor is a well accepted temperature standard because of its consistent and repeatable temperature response above 30 K SoftCal gives platinum sensors better accuracy than their nominal matching to the DIN 43760 curve SoftCal Point 1 SoftCal Point 2 SoftCal Point 3 Liquid Nitrogen Room Temperature High Temperature Boiling Point Point Point 77 35 K 305 K 480 K EA Ya AA E 0 50 100 150 200 250 300 350 400 450 500 550 600 650 Band LN 50 100 K 200 325 K 400 600 K Acceptable Tempe
11. Remote Interface Mode Query MODE term lt mode gt term n Refer to command for description Control Loop Manual Heater Power MHP Output Command MOUT lt loop gt lt value gt term n nnnnnniterm lt loop gt Specifies loop to configure 1 or 2 lt value gt Specifies value for manual output MOUT 1 22 45 term Control Loop 1 manual heater output is 22 45 Control Loop Manual Heater Power MHP Output Query MOUT lt loop gt term n lt loop gt Specifies which loop to query 1 or 2 lt value gt nnnnnnfterm Refer to command for description Remote Operation 6 35 Lake Shore Model 331 Temperature Controller User s Manual PID Control Loop PID Values Command Input PID lt loop gt lt P value gt lt I value gt lt D value gt term Format n nnnnnn nnnnnn nnnnNnnn lt loop gt Specifies loop to configure 1 or 2 lt P value gt The value for control loop Proportional gain 0 1 to 1000 lt value gt The value for control loop Integral reset 0 1 to 1000 lt D value gt The value for control loop Derivative rate 0 to 200 Remarks Setting resolution is less than 6 digits indicated Example PID 1 10 50 term Control Loop 1 P is 10 and is 50 PID Control Loop PID Values Query Input PID lt loop gt term Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt P value gt lt l value gt lt D value gt term Format nnnnnn tnnnnnn tnnnnnn Ref
12. Thermo 25mV 25 mV NA Thermocouple Chromel AuFe 0 07 y Type E Chromel Constantan mV K Positive Thermo 50mV 150 mV NA Thermocouple Type K Chromel Alumel Type T Copper Constantan Refer to the Lake Shore Temperature Measurement and Control Catalog for complete details on all Lake Shore Temperature Sensors 4 4 1 Diode Sensor Input Setup Diode sensors include the Silicon and Gallium Aluminum Arsenide GaAlAs detailed in Table 4 1 More detailed specifications are provided in Table 1 2 Input ranges for are fixed to 0 2 5 V for silicon diodes and 0 7 5 V for GaAlAs diodes Both use a sensor excitation current of 10 pA To setup a diode sensor input press the Input Setup key The first screen appear as follows Use the A or Y key to cycle through the sensor types shown in Table 4 1 with Silicon Diode and GaAlAs Diode being the relevant choices Press the Enter key Proceed to Paragraph 4 5 1 to select a temperature curve or press the Escape key to return to the normal display Operation 4 7 4 4 2 4 4 2 1 Lake Shore Model 331 Temperature Controller User s Manual Resistor Sensor Input Setup Resistor sensors include the Platinum Rhodium lron and various NTC RTD sensors teg Cernox Rox Thermox detailed in Table 4 1 More detailed specifications are provided in Table 1 2 Input range is fixed to type of sensor The excitation current ap
13. WARNING To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures Identify the line input assembly on the instrument rear panel See Figure 8 1 Turn the line power switch OFF O Remove the instrument power cord With a small screwdriver release the drawer holding the line voltage selector and fuse Slide out the removable plastic fuse holder from the drawer Rotate the fuse holder until the proper voltage indicator shows through the window Verify the proper fuse value Re assemble the line input assembly in the reverse order 9 Verify the voltage indicator in the window of the line input assembly 10 Connect the instrument power cord Dm Jo mF WN gt 11 Turn the line power switch On I Line Cord Power Switch Screwdriver Fuse Input O Off On Slot Drawer N 100 120 220 240 V S 10 5 Voltage 100 120V 1 5AT250V 0 25x1 25 50 60 Hz 120 VA MAX 220 240V 0 75 A T 250V 5x20mm F 331 8 1 eps Figure 8 1 Power Fuse Access 8 3 FUSE REPLACEMENT Use the following procedure to remove and replace a line fuse WARNING To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures CAUTION For continued protection against fire hazard replace only with the same fuse type and rating specified for the line for the line voltage selected NOTE Test fuse with an
14. ivi a a a a R a a a aa aa iE 4 11 4 5 1 Diode Sensor Curve Selection niiin arene iio eo SEENEN 4 12 4 5 2 Resistor Sensor Curve Selection ooooooccccnnonicononocinonononononannnonnnnn cnn nn n cnc nano nn rr nn cnn rr 4 12 4 5 3 Thermocouple Sensor Curve Selection ooooococcccconocccinonaccnononcncnnnn nn nn nono cnn nao nn nn nana nn nr nn nn rca nan nnnncnnns 4 12 Table of Contents Lake Shore Model 331 Temperature Controller User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 4 6 TEMPERATURE CONTROL iscing oiva Add rata 4 13 4 6 1 Control LOOPS EE 4 13 4 6 2 Control Modes sitio ticas 4 14 4 6 3 Tuning MOdeS E 4 14 4 7 CONTROL SETUP iia tt ti d EE E 4 14 4 8 MANUAL TUNING viii bae 4 16 4 8 1 Manually Setting Proportional P 4 16 4 8 2 Manually Setting Integral UN 4 16 4 8 3 Manually Setting Derivative Di 4 17 4 8 4 Setting Manual Heater Power MHP Output 4 17 4 9 AUTOTUNE CLOSED LOOP PID CONTROL cocococccococononononcnnnonononononononanoncnrnnnnnnn nar nn rr naar n cn rre nnnnns 4 18 4 10 ZONE SETTINGS CLOSED LOOP CONTROL cccccococcncnononcnononnnonononcnnnnnnnnnnnnnnnnnnnn non nn naar cnn nannnncnnnos 4 19 4 11 ele RRE 4 22 4 12 KI TEE 4 23 4 13 HEATER RANGE AND HEATER OFF 0 ceecsceeeeeseeeeeeeeeeeesaeeeeeeeaeeeeeeeeeesaaeeeseseaaeeesnneeeeeenaeeeesenaes 4 24 4 14 MAT aaa boa 4 25 4 14 1 Max Mifi annie i aep eenn i agaaa n eaaa aaa a e r ai a aaraa 4 25 4 14 2 Linda ii
15. 10 090 0 0 95327 075 0 0 99110 11 070 0 1 00460 060 0 1 02840 12 055 0 1 04070 040 0 1 07460 13 040 0 1 07460 036 0 1 08480 14 034 0 1 09020 034 0 1 09090 15 032 0 1 09700 032 0 1 09810 16 030 0 1 10580 030 0 1 10800 17 029 0 1 11160 029 0 1 11500 18 028 0 1 11900 028 0 1 12390 19 027 0 1 13080 027 0 1 13650 20 026 0 1 14860 026 0 1 15590 21 025 0 1 17200 025 0 1 18770 22 023 0 1 25070 024 0 1 23570 23 021 0 1 35050 022 0 1 33170 24 017 0 1 63590 018 0 1 65270 25 015 0 1 76100 013 0 1 96320 26 013 0 1 90660 009 0 2 17840 27 009 0 2 11720 004 0 2 53640 28 003 0 2 53660 003 0 2 59940 29 001 4 2 59840 001 4 2 65910 These Lake Shore sensors are no longer in production D 2 Curve Tables Lake Shore Model 331 Temperature Controller User s Manual Table D 4 Lake Shore PT 100 1000 Platinum RTD Curves Break PT 100 PT 1000 point Temp K Ohms Q Temp K Ohms Q 1 030 0 3 820 030 0 38 20 2 032 0 4 235 032 0 42 35 3 036 0 5 146 036 0 51 46 4 038 0 5 650 038 0 56 50 5 040 0 6 170 040 0 61 70 6 042 0 6 726 042 0 67 26 7 046 0 7 909 046 0 79 09 8 052 0 9 924 052 0 99 24 9 058 0 12 180 058 0 121 80 10 065 0 15 015 065 0 150 15 11 075 0 19 223 075 0 192 23 12 085 0 23 525 085 0 235 25 13 105 0 32 081 105 0 320 81 14 140 0 46 648 140 0 466 48 15 180 0 62 980 180 0 629 80 16 210 0 75 044 210 0 750 44 17 270 0 98 784 270 0 987 84 18 315 0 116 270 315 0 1162 70 19 355 0 131 616 355 0 1316 16 20 4
16. Disable Setpoint Ramp Off Heater Output Display Current Display Format Display Location 1 Input A Temp K Display Location 2 Input B Temp K Display Location 3 Setpoint Display Location 4 Heater Output Display Brightness 75 Heater Heater Range Off Input Setup Diode Resistor Configuration Input Type ssassn Silicon Diode A ends DT 470 Input Setup Thermocouple Configuration Input Type saosan Thermocouple 25mV GUN Oni Type K Room Comp On Room Cal Cleared Interface Bad ina tel n 9600 IEEE Address 12 IEEE Terminators CR LF Emulation Mode 331 Keypad Locking Mode Unlocked Lock Code IA 123 Loop Selected Loop Loop 1 Math OUNCE veria dica Temp K Linear Equation MX B Linear Equation M Value 0 0000 Linear Equation X Source Temp K Linear Equation B Source Value Linear Equation B Value 0 0000 A Y Off PID Manual Heater Power MHP Output Proportional P 50 000 Integral e 20 000 Derivative Di 0 0000 MHP Output 0 0000 Remote Local Remote oc Local Setpoint Setpoint Value 0 000K Tuning Tuning Mode Manual PID Zone Settings All Zones Setpoint Limit 0 000K Proportional P 50 000 Integral e 20 000 Derivative Di 0 0000 Manual Output 0 0000 Operation
17. HEATER SELECTION AND INSTALLATION There is a variety of resistive heaters that can be used as the controlled heating source for temperature control The mostly metal alloys like nichrome are usually wire or foil Shapes and sizes vary to permit installation into different systems Heater Resistance and Power Cryogenic cooling systems have a wide range of cooling power The resistive heater must be able to provide sufficient heating power to warm the system The Model 331 can supply up to 50 W of power to a heater if the heater resistance is appropriate The Model 331 heater output current source has a maximum output of 1 A limiting maximum power to Max Power watts 1 ampere x Resistance ohms Even though the Model 331 output is a current source it has a voltage limit called the compliance voltage of 50 V which also limits maximum power 2 Max Power watts 50 vols Resistance ohms Both limits are in place at the same time so the smallest of the two computations gives the maximum power available to the heater A heater of 50 Q allows the instrument to provide its maximum power of 50 watts A typical smaller resistance of 25 Q allows 25 watts of power while a typical larger resistance of 100 Q is limited by compliance voltage to 25 watts The resistor chosen as a heater must be able to withstand the power being dissipated in it Pre packaged resistors have a power specification that is usually given for the resisto
18. Input Connector 6 pin DIN Ceramic isothermal block Isolation A D Resolution Input Accuracy Measurement Resolution Maximum Update Rate User Curves SoftCal Math Filter Control Control Loops Control Type Tuning Control Stability PID Control Settings Proportional Gain Integral Reset Derivative Rate Manual Heater Zone Control Setpoint Ramping Sensor inputs optically isolated from other circuits but not each other 24 bit Sensor dependent Refer to Table 1 2 Sensor dependent Refer to Table 1 2 10 readings per second on each input except 5 readings per second on input A when configured as thermocouple Room for twenty 200 point CalCurves or user curves Improves accuracy of DT 470 Diode to 0 25 K from 30 to 375 K Improves accuracy of Platinum RTDs to 0 25 K from 70 to 325 K Stored as user curves Maximum Minimum and Linear Equation Mx B or M x B Averages 2 to 64 input readings 2 on Model 331S 1 on Model 331E Closed Loop Digital PID with Manual Heater or Open Loop AutoTune one loop at a time Manual PID Zones Sensor dependent refer to performance chart 0 1000 with 0 1 setting resolution 1 1000 1000 s with 0 1 setting resolution 1 200 with 1 resolution 0 100 with 0 001 setting resolution 10 temperature zones with P D Manual Heater and Heater Range 0 1 to 100 K min Protection Cur
19. Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 5 ADVANCED OPERATION 5 0 GENERAL This chapter covers the advanced operation of the Model 331 Temperature Controller Advanced operation consists of the functions related to temperature response curves A temperature response curve can be entered into the Model 331 in several ways order it factory installed Paragraphs 2 2 and 7 2 create a SoftCal curve Paragraph 5 3 load a curve via the computer interface refer to the various curve commands detailed in Paragraph 6 3 or enter a user generated curve from the front panel Advanced functions include details on curve numbers and storage in Paragraph 5 1 front panel curve entry operations in Paragraph 5 2 and SoftCal in Paragraph 5 3 5 1 CURVE NUMBERS AND STORAGE The Model 331 has 20 standard curve locations numbered 1 thru 20 At present not all locations are occupied by curves the others are reserved for future updates If a standard curve location is in use the curve can be viewed using the edit operation Standard curves can not be changed by the user and reserved locations are not available for user curves The Model 331 has 20 user curve locations numbered 21 thru 41 Each location can hold from 2 to 200 data pairs breakpoints including a value in sensor units and a corresponding value in kelvin Using fewer than 200 breakpoints will not increase the number of available curve locations SoftCal generated curv
20. Liquid Helium Liquid Nitrogen Room Temperature Boiling Point Boiling Point Point 4 2K 77 35 K 305 K K Pop 0 25 50 75 100 125 150 175 350 E GE 2 10K 50 100 K 200 325 K Acceptable Temperature Range for Silicon Diode SoftCal Inputs C 331 5 1 eps Figure 5 1 SoftCal Temperature Ranges for Silicon Diode Sensors Point 1 Calibration data point at or near the boiling point of helium 4 2 K Temperatures outside 2 Kto 10 K are not allowed This data point improves between the calibration data point and 28K Points 2 and 3 improve temperatures above 28 K Point 2 Calibration data point at or near the boiling point of nitrogen 77 35 K Temperatures outside 50 K to 100 K are not allowed This data point improves accuracy between 28 K and 100 K Points 2 and 3 together improve accuracy to room temperature and above Point 3 Calibration data point near room temperature 305 K Temperatures outside the range of 200 K to 350 K are not allowed 5 3 2 SoftCal Accuracy With Silicon Diode Sensors A SoftCal calibration is only as good as the accuracy of the calibration points The accuracies listed for SoftCal assume 0 01 K for 4 2 K liquid helium 0 05 K for 77 35 K liquid nitrogen and 305 K room temperature points Users performing the SoftCal with Lake Shore instruments should note that the boiling point of liquid cryogen though accurate is affected by atmospheric pressure Use calibrated standard sensors if possible
21. P N 106 737 is included with the Model 331 For convenient installation of wires the terminal block may be removed from the socket According to the manufacturer up to 12 AWG stranded copper wire may be used with the terminal block though it is unlikely that wire that large is required to carry the rated 5 amp current of the relay 3 10 INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE The following is an initial instrument setup and checkout procedure The intent is to verify basic operation of the unit before beginning use for measurements The procedure assumes a setup with two Lake Shore DT 470 Silicon Diode Sensors one control loop a single 50 2 heater all readings in Kelvin and running in a liquid nitrogen environment CAUTION Check power source for proper voltage before connecting the line cord to the Model 331 Also check the line voltage setting on the window in the fuse drawer Damage to unit may occur if connected to improper voltage 1 Check power source for proper voltage The Model 331 operates with 100 120 220 or 240 5 10 AC input voltage 2 Check window in fuse drawer for proper voltage setting If incorrect refer to Paragraph 8 2 3 Ensure the power switch is in the off O position CAUTION The sensor must be connected to the rear of the unit before applying power to the Temperature Controller Damage to the sensor may occur if connected with power on 4 Verify your sensor installation in the liquid nit
22. Run IBCONF to configure the GPIB PCII IIA board and dev 12 Set the EOS byte to OAH and Enable Repeat Addressing to Yes See Figure 6 3 IBCONF modifies gpib com S E eow NA 7 Connect the instrument to the interface board and power up the instrument Verify the address is 12 and terminators are CR LF Quick Basic Program The IEEE 488 interface program in Table 6 3 works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible running DOS or in a DOS window It assumes your IEEE 488 GPIB card is installed and operating correctly refer to Paragraph 6 1 4 3 Use the following procedure to develop the Serial Interface Program in Quick Basic 1 Copy c gpib pc Qbasic qbib obj to the QuickBasic directory QB4 2 Change to the QuickBasic directory and type link Jo qbib obj bqlb4x lib where x 0 for QB4 0 and 5 for QB4 5 This one time only command produces the library file qbib qlb The procedure is found in the National Instruments QuickBasic readme file Readme qb 3 Start QuickBasic Type qb I qbib qlb Start QuickBasic in this way each time the IEEE interface is used to link in the library file 4 Create the IEEE example interface program in QuickBasic Enter the program exactly as presented in Table 6 3 Name the file ieeeexam bas and save 5 Run the program 6 Type a command query as described in Paragraph 6 1 4 5 7 Type EXIT to quit the program 6 10 Remote Operation Lake Shore Model
23. Sets values for both P and parameters D is set to zero This mode is recommended for stable control at a constant temperature lt may take slightly longer to stabilize after setpoint change than Auto PID Expect some overshoot or undershoot of the setpoint and stable temperature control at the setpoint value Auto PID Sets values for P and D parameters D is always set to 100 This mode is recommended when setpoint changes are frequent but temperature is allowed to stabilize between changes Stability at setpoint may be worse than Auto PI in noisy systems Expect slightly less overshoot or undershoot than the other modes and control at the setpoint value Once AutoTune mode is selected the Tune annunciator turns on steady to indicate that AutoTune is on No activity takes place until the setpoint is changed at least 0 5 K At that time the Tune annunciator blinks to indicate the instrument is gathering data This process takes from 1 to 17 minutes depending on the system reaction time The tune annunciator stops blinking when calculations are complete and new parameter values have been stored The annunciator will also stop blinking if the algorithm is unable to complete Possible reasons include setpoint change too small manual control parameter changed during tuning heater not turned on or control sensor curve not selected If the controller is not tuned satisfactorily on the first attempt make several small 2 degree setpoint chan
24. The arrangement of wires in a cable is also important For best results voltage leads V and V should be twisted together and current leads I and should be twisted together The twisted pairs of voltage and current leads should then be covered with a braided or foil shield which is connected to the shield pin of the instrument This type of cable is available through local electronics suppliers Instrument specifications are given assuming 10 feet of sensor cable Longer cables 100 feet or more can be used but environmental conditions may degrade accuracy and noise specifications Refer to Paragraph 2 3 6 for information about wiring inside the cryostat 3 5 3 Grounding and Shielding Sensor Leads The sensor inputs are isolated from earth ground to reduce the amount of earth ground referenced noise that is present on the measurement leads This isolation can be defeated by connecting sensor leads to earth ground on the chassis of the instrument or in the cooling system If one sensor lead must be grounded ground only one lead and ground it in only one place Grounding leads on more than one sensor prevents the sensor excitation current sources from operating Shielding the sensor lead cable is important to keep external noise from entering the measurement A shield is most effective when it is near the measurement potential so the Model 331 offers a shield that stays close to the measurement The shield of the sensor cable should be connected
25. The heater is connected between the HI and LO terminals The ground terminal is reserved for shielding the heater leads when necessary HEATER OUTPUT HI LO L cov wax Loop 1 Heater Output Wiring Heater output current is what determines the size gauge of wire needed to connect the heater The maximum current that can be sourced from the Loop 1 heater output is 1 A When less current is needed to power a cooling system it can be limited with range settings When setting up a temperature control system the lead wire for the heater be capable of carrying a continuous current that is greater than the maximum current Wire manufactures recommend 30 AWG or larger wire to carry 1 A of current but there is little advantage in using wire smaller than 20 to 22 AWG outside the cryostat Inside the cryostat smaller gauge wire is often desirable It is recommended to use twisted heater leads Large changes in heater current can induce noise in measurement leads and twisting reduces the effect It is also recommended to run heater leads in a separate cable from the measurement leads to further reduce interaction There is a chassis ground point at the rear panel of the instrument for shielding the heater cable The cable shield can be tied to this point with a single banana plug The shield should not be connected at the opposite end of the cable and should never be tied to the heater output leads The Loop 1 heater output is isolated from
26. Turn off timer Remote Operation 6 19 Lake Shore Model 331 Temperature Controller User s Manual 6 2 7 2 Quick Basic Serial Interface Program Setup The serial interface program listed in Table 6 7 works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible running DOS or in a DOS window with a serial interface It uses the COM1 communication port at 9600 Baud Use the following procedure to develop the Serial Interface Program in Quick Basic Start the Basic program Enter the program exactly as presented in Table 6 7 Adjust the Com port and Baud rate in the program as necessary Lengthen the TIMEOUT count if necessary Save the program Run the program Type a command query as described in Paragraph 6 2 7 3 Type EXIT to quit the program E A Mm Table 6 7 Quick Basic Serial Interface Program CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may need more BAUDS 9600 TERMS CHR 13 CHR 10 Terminators are lt CR gt lt LF gt OPEN COM1 BAUDS 0 7 1 RS FOR RANDOM AS 1 LEN 256 LINE INPUT ENTER COMMAND or EXIT CMDS Get command from keyboard CNDS UCASES CMDS Change input to upper case IF CMD EXIT THEN CLOSE 1 END Get out on Exit CMDS CMDS TERMS PRINT 1 CMDS Send command to instrument IF INSTR CMDS lt gt 0 THEN Test for query RSS me If query read response N 0 Clr return string and cou
27. mV K where V K volts per kelvin Q K ohms per kelvin log Q K logarithm of the resistance per kelvin and mV K millivolts per kelvin For this example we will select V K Press the Enter key Use the numerical keypad to enter a setpoint limit in kelvin appropriate for the sensor being used For this example we will enter 475 00K Press the Enter key 1 The temperature coefficient positive or negative of the curve is displayed The coefficient is calculated from the first two points of the curve and cannot be changed Press the Enter key 5 4 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual Edit Curve Continued 5 2 1 1 Now that the curve identification parameters are entered it is time to enter curve breakpoints TE mo CH The cursor initially blinks on the curve breakpoint number When the cursor is in this position use the A or Y key to scroll through the breakpoints in the curve Press the Enter key to modify the current breakpoint Use the numerical keypad to enter the applicable sensor value For this example we will enter 0 09062 V then press the Enter key The cursor will jump to the temperature reading Again use numerical keypad to enter the applicable temperature in kelvin For this example we will enter 475 0 K Press the Enter key ru Use the numerical keypad to enter the remaining voltage and temperature points After entering the final poi
28. the existing setting and return to the normal display Use the A or Y key to toggle between 331 and 330 The default setting is 331 If 331 mode is selected pressing the Enter key will return you to the normal display To support owners of the Lake Shore Model 330 Temperature Controller 330 Emulation Mode is provided The 330 Emulation Mode only affects remote operation front panel operation of the Model 331 is not changed In 330 Emulation Mode curve locations are mapped to match Model 330 locations For example the DT 500 D Curve found at curve location 3 in the Model 331 is mapped to location 0 when in 330 mode This applies to the following remote commands ACUR ACUR BCUR BCUR The following Model 330 commands are not supported in 330 Emulation Mode CUID CURV CURV ECUR KCUR and SCAL Please refer to your Model 330 User s Manual for any additional questions concerning remote commands Selecting 330 Emulation Mode causes two additional screens to appear BEZ E y Eu LL A emm Use the A or Y key to toggle between Sample Channel A or B The default setting is A Press the Enter key You will see the following display Use the A or Y key to cycle through the Sample Units K C and Sensor where K kelvin C degrees Celsius and Sensor volts V or ohms Q The default setting is K Press the Enter key You will return to the normal display 4 36 Operatio
29. using the left and right arrow keys This address is used to compute the talk and listen addresses which identify the board or device on the GPIB Valid primary addresses range from 0 to 30 00H to 1EH Adding 32 to the primary address forms the Listen Address LA Adding 64 to the primary address forms the Talk Address TA EXAMPLE Selecting a primary address of 10 yields the following 10 32 42 10 64 74 Listen address Talk address C 331 6 3 eps Figure 6 3 Typical National Instruments GPIB Configuration from IBCONF EXE Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Table 6 3 Quick Basic IEEE 488 Interface Program IEEEEXAM BAS EXAMPLE PROGRAM FOR IEEE 488 INTERFACE This program works with QuickBasic 4 0 4 5 on an IBM PC or compatible The example requires a properly configured National Instruments GPIB PC2 card The REM SINCLUDE statement is necessary along with a correct path to the file QBDECL BAS CONFIG SYS must call GPIB COM created by IBCONF EXE prior to running Basic There must be QBIB QBL library in the QuickBasic Directory and QuickBasic must start with a link to it All instrument settings are assumed to be defaults Address 12 Terminators lt CR gt lt LF gt and EOI active To use type an instrument command or query at the prompt The computer transmits to the instrument and displays any response If no query is sent the instrument respon
30. 1 09864 85 001 7 1 69367 28 190 0 0 77857 57 033 0 1 10060 86 001 4 1 69818 29 180 0 0 80139 58 032 0 1 10263 Curve Tables Lake Shore Model 331 Temperature Controller User s Manual Table D 2 Standard DT 670 Diode Curve _ Pov Temp K _ ov Temp K _ _ ov Temp K 0 090570 1 01064 1 19475 0 110239 1 02125 1 24208 0 136555 1 03167 i 1 26122 0 179181 1 04189 1 27811 0 265393 y 1 05192 1 29430 0 349522 S 1 06277 S 1 31070 0 452797 3 1 07472 1 32727 0 513393 1 09110 1 34506 0 563128 1 09602 1 36423 0 607845 10014 1 38361 0 648723 d 10393 i 1 40454 0 686936 10702 1 42732 0 722511 3 10974 i 1 45206 0 755487 11204 1 48578 0 786992 S 11414 1 53523 0 817025 11628 i 1 56684 0 844538 d 11853 1 58358 0 869583 12090 1 59690 0 893230 E 12340 3 1 60756 0 914469 12589 1 62125 0 934356 12913 1 62945 0 952903 d 13494 S 1 63516 0 970134 14495 1 63943 0 986073 16297 1 64261 0 998925 17651 1 64430 Table D 3 Lake Shore DT 500 Series Silicon Diode Curves Break DT 500 D Curve DT 500 E1 Curve point Temp K Volts Temp K Volts 1 365 0 0 19083 330 0 0 28930 2 345 0 0 24739 305 0 0 36220 3 305 0 0 36397 285 0 0 41860 4 285 0 0 42019 265 0 0 47220 5 265 0 0 47403 240 0 0 53770 6 240 0 0 53960 220 0 0 59260 7 220 0 0 59455 170 0 0 73440 8 170 0 0 73582 130 0 0 84490 9 130 0 0 84606 100 0 0 92570
31. 5 TOP OF ENCLOSURE REMOVE AND REPLACE PROCEDURE WARNING To avoid potentially lethal shocks turn off controller and disconnect it from AC power line before performing this procedure Only qualified personnel should perform this procedure REMOVAL Set power switch to Off O and disconnect power cord from rear of unit If attached remove 19 inch rack mounting brackets Use 5 64 hex key to remove four screws attaching top panel to unit Use 5 64 hex key to loosen two rear screws attaching bottom panel to unit Carefully remove the back bezel by sliding it straight back away from the unit Slide the top panel back and remove it from the unit INSTALLATION Slide the top panel forward in the track provided on each side of the unit Carefully replace the back bezel by sliding it straight into the unit Use 5 64 hex key to install four screws attaching top panel to unit Use 5 64 hex key to tighten two rear screws attaching bottom panel to unit If required reattach 19 inch rack mounting brackets Connect power cord to rear of unit and set power switch to On I DABAN gt Dm Foz 8 6 FIRMWARE AND NOVRAM REPLACEMENT There are three integrated circuits ICs that may potentially require replacement The location of the ICs is shown in Figure 8 7 e Input Microcontroller U16 Contains software that configures the inputs takes readings and performs control functions Has a sticker on top labeled M331IF HEX and a version num
32. 50 mV so any part of the curve that extends beyond 50 mV is not usable by the instrument Amessage of S OVER or S UNDER on the display indicates that the measured thermocouple input is over or under the 50 mV range Advanced Operation 5 5 5 2 2 5 2 3 Lake Shore Model 331 Temperature Controller User s Manual Erase Curve User curves that are no longer needed may be erased Erase Curve sets all identification parameters to default and blanks all breakpoint values To erase an existing user curve press the Curve Entry key Press the A or Y key until you see the following display Press the Enter key You can press the Escape key anytime during this routine to return to the normal display Use the A or Y key to cycle through the various user curve numbers 21 thru 41 You cannot erase the standard curve numbers 01 thru 20 Once the user curve number is selected press the Enter key You will see the following message Press the Escape key to cancel or the Enter key to erase the selected user curve You now return to the normal display Copy Curve Temperature curves can be copied from one location inside the Model 331 to another This is a good way to make small changes to an existing curve Curve copy may also be necessary if the user needs the same curve with two different temperature limits or needs to extend the range of a standard curve The curve that is copied from is al
33. 579930 102 50 66 0 774384 308 00 100 7 657460 608 00 33 3 504020 106 50 67 0 840638 311 00 101 7 104410 610 00 34 3 427530 110 50 68 1 126350 324 00 D 10 Curve Tables
34. 7 70 76 3 61092 1 150 11 3 36495 27 5 44 3 42910 7 35 T77 3 62451 1 055 12 3 36659 26 4 45 3 43202 7 00 78 3 63912 0 965 13 3 36831 25 3 46 3 43515 6 65 79 3 65489 0 880 14 3 37014 24 2 47 3 43853 6 30 80 3 67206 0 800 15 3 37191 23 2 48 3 44230 5 94 81 3 69095 0 725 16 3 37377 22 2 49 3 44593 5 62 82 3 71460 0 645 17 3 37575 21 2 50 3 44984 5 30 83 3 73889 0 575 18 3 37785 20 2 51 3 45355 5 02 84 3 76599 0 510 19 3 37942 19 50 52 3 45734 4 76 85 3 79703 0 448 20 3 38081 18 90 53 3 46180 4 48 86 3 83269 0 390 21 3 38226 18 30 54 3 46632 4 22 87 3 87369 0 336 22 3 38377 17 70 55 3 47012 4 02 88 3 92642 0 281 23 3 38522 17 15 56 3 47357 3 85 89 3 98609 0 233 24 3 38672 16 60 57 3 47726 3 68 90 4 05672 0 190 25 3 38829 16 05 58 3 48122 3 51 91 4 14042 0 153 26 3 38993 15 50 59 3 48524 3 35 92 4 24807 0 120 27 3 39165 14 95 60 3 48955 3 19 93 4 40832 0 088 28 3 39345 14 40 61 3 49421 3 03 94 4 57858 0 067 29 3 39516 13 90 62 3 49894 2 88 95 4 76196 0 055 30 3 39695 13 40 63 3 50406 2 73 96 4 79575 0 051 31 3 39882 12 90 64 3 50962 2 58 97 4 81870 0 050 32 3 40079 12 40 65 3 51528 2 44 33 3 40286 11 90 66 3 52145 2 30 Curve Tables D 5 Lake Shore Model 331 Temperature Controller User s Manual Table D 7 Type K Nickel Chromium vs Nickel Aluminum Thermocouple Curve SSC e EE me a T SI ee Se 1 6 45774 3 15 48 6 10828 57 4 95 2 95792 192 142 18 1482 714 5 2 6 45733 3 68 49 6 08343 59 4 96 2 82629 196 143 19 2959 741 5
35. Compatibility EMC of electronic equipment is a growing concern worldwide Emissions of and immunity to electromagnetic interference is now part of the design and manufacture of most electronics To qualify for the CE Mark the Model 331 meets or exceeds the requirements of the European EMC Directive 89 336 EEC as a CLASS A product A Class A product is allowed to radiate more RF than a Class B product and must include the following warning WARNING This is a Class A product In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures The instrument was tested under normal operating conditions with sensor and interface cables attached If the installation and operating instructions in the User s Manual are followed there should be no degradation in EMC performance This instrument is not intended for use in close proximity to RF Transmitters such as two way radios and cell phones Exposure to RF interference greater than that found in a typical laboratory environment may disturb the sensitive measurement circuitry of the instrument Pay special attention to instrument cabling Improperly installed cabling may defeat even the best EMC protection For the best performance from any precision instrument follow the grounding and shielding instructions in the User s Manual In addition the installer of the Model 331 should consider the following Shield measurement and comp
36. Connector Polarities Thermocouple Installation Thermocouples are commonly used in high temperature applications Cryogenic use of thermocouples offers some unique challenges A general installation guideline is provided in Paragraph 2 3 Consider the following when using thermocouples at low temperatures e Thermocouple wire is generally more thermally conductive than other sensor lead wire Smaller gauge wire and more heat sinking may be needed to prevent leads from heating the sample Attaching lead wires and passing through vacuum tight connectors are often necessary in cryogenic systems Remember the thermocouple wire is the sensor any time it joins or contacts other metal there is potential for error e Temperature verification and calibration of room temperature compensation is difficult after the sensor is installed When possible keep a piece of scrap wire from each installation for future use Grounding and Shielding For lowest measurement noise do not ground thermocouple sensors The instrument usually operates with more noise if one of the thermocouples is grounded Grounding both thermocouples is not recommended The instrument does not offer a shield connection on the terminal block Twisting the thermocouple wires helps reject noise If shielding is necessary extend the shield from the oven or cryostat to cover the thermocouple wire but do not attach the shield to the instrument Installation 3 7 3 7 3 7 1
37. D Style Connector Paragraph 6 2 1 Figure 8 5 HEATER OUTPUT and Ground Banana Paragraph 3 7 Figure 8 3 Jacks INPUT A and INPUT B Sensor or Paragraphs 3 5 Figure 8 2 Thermocouple Input Connectors and 3 6 RELAYS and ANALOG OUTPUT Terminal Paragraphs 3 8 Figure 8 4 Block Model 331S Only and 3 9 IEEE 488 INTERFACE Connector Paragraph 8 4 2 Figure 8 6 Model 331S Only Figure 3 1 Model 331 Rear Panel 3 2 Installation Lake Shore Model 331 Temperature Controller User s Manual AA LINE INPUT ASSEMBLY 3 4 1 3 4 2 3 4 3 This section describes how to properly connect the Model 331 to line power Please follow these instructions carefully to ensure proper operation of the instrument and the safety of operators Line Cord Power Switch Fuse Drawer Input O Off On N 100 120 220 240 V S 10 5 Voltage 100 120V 1 5AT250V 0 25x1 25 50 60 Hz 120 VA MAX 220 240V 0 75 A T 250V 5x20mm F 331 3 2 eps Figure 3 2 Line Input Assembly Line Voltage The Model 331 has four different AC line voltages configurations so that it can be operated from line power anywhere in the world The nominal voltage and voltage range of each configuration is shown below The recommended setting for 230 V operation is 240 V Nominal Minimum Maximum 100 V 90 V 105 V 120 V 108 V 126 V 220 V 198 V 231 V 240 V 216 V 252 V Verify that the AC line voltage indicator in t
38. ENTER COMMAND RANGE 1 RANGE Heater range command followed by a query Instrument will change to heater Low setting then return a string RESPONSE 1 term with the present setting The following are additional notes on using either Serial Interface program e Ifyou enter a correctly spelled query without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries and should have a space separating the command and associated parameters e Leading zeros and zeros following a decimal point are not needed in a command string but they will be sent in response to a query A leading is not required but a leading is required 6 2 8 Troubleshooting New Installation 1 Check instrument Baud rate 2 Make sure transmit TD signal line from the instrument is routed to receive RD on the computer and vice versa Use a null modem adapter if not 3 Always send terminators 4 Send entire message string at one time including terminators Many terminal emulation programs do not 5 Send only one simple command at a time until communication is established 6 Be sure to spell commands correctly and use proper syntax Old Installation No Longer Working 1 Power instrument off then on again to see if it is a soft failure 2 Power computer off then on again to see if communication port is locked up 3 Verify that Baud rate has not been changed on the instrument during a me
39. Input CALG lt input gt lt type gt term Format a nn lt input gt A B or V lt type gt 0 7 or 10 13 Returned lt value gt term Format nnnnnnn Refer to command for description CALREAD Six Digit Input Reading Query Input CALREAD lt input gt term Format a lt input gt AorB Returned lt value gt term Format n nnnnn Remarks Returns 6 digit value of selected input reading Used for CALZ and CALG functions 8 16 Service Lake Shore Model 331 Temperature Controller User s Manual CALRSTG Reset Gain Calibration Constant Command Input CALRSTG lt input gt lt type gt term Format a nn lt input gt Specifies which input for which to reset the gain calibration constant to the default value Valid entries are A or B for inputs and V for the analog output lt type gt Specifies the input sensor type Valid entries are 0 Silicon Diode 6 Thermo 25mV 1 GaAlAs Diode or Analog Output 7 Thermo 50mV 2 1000 Plat 250 Reversal Off 10 1004 Plat 250 Reversal On 3 100Q Plat 500 Reversal Off 11 1000 Plat 500 Reversal On 4 10000 Plat Reversal Off 12 1000Q Plat Reversal On 5 NTC RTD Reversal Off 13 NTC RTD Reversal On Remarks Resets the gain calibration constant for a specific input and type to its default value CALRSTZ Reset Zero Offset Calibration Constant Command Input CALRSTZ lt input gt lt type gt term Format a nn lt
40. K 20 mK at 4 2 K 48 mK at 30 K 50 mK at 30 K 24 1 mK at 4 2 K 125 mK at 77 K 255 mK at 77 K 39 mK at 77 K 44 mK at 77 K 238 mK at 20 K 105 mK at 300 K 180 mK at 300 K 84 mK at 300 K 112 mK at 300 K 705 mK at 40 K 100 mK at 475 K 123 mK at 475 K 195 mK at 800 K 272 mK at 800 K Temperature Accuracy including electronic accuracy CalCurve and calibrated sensor Control Stability Sensor Units 20 uV 40 uV 4 mQ 40 mQ 80 MQ Temperature Equivalence 0 6 mK at 4 2 K 0 2 mK at 4 2 K 22 mK at 30 K 22 mK at 30 K 1 mK at 4 2 K 11 mK at 77 K 32 mK at 77 K 9 5 mK at 77 K 9 5 mK at 77 K 20 mK at 20 K 8 4 mK at 300 K 14 mK at 300 K 10 mK at 300 K 10 mK at 300 K 76 mK at 40 K 9 mK at 475 K 13 mK at 475 K 11 mK at 800 K 12 mK at 800 K Magnetic Field Use Recommended for Recommended for Recommended for Recommended for Recommended for T260K amp B lt 3T T gt 42K84B lt 5T T gt 40K8B lt 25T T gt 40K8B lt 25T T gt 2K8B lt 10T Sensor no longer sold by Lake Shore Typical sensor sensitivities were taken from representative calibrations for the sensor listed Introduction 1 5 Lake Shore Model 331 Temperature Controller User s Manual Table 1 2 Model 331 Sensor Input Performance Chart Continued Example LSCI Sensor TX 104 GB with CGR 1 500 with CX 1050 SD with Chromel versus Type K H 70L calibration 1 4L calibration 1 4L calibration AuFe 0 07 Standard Sensor Curve Requires calibrated Requires calibrated Requi
41. Loop 1 and 2 Operates with Control Setup Setpoint PID MHP Zone Settings AutoTune Heater Range and Heater Off Refer to Paragraph 4 6 1 Heater Range For Loop 1 allows selection of High 50 W Medium 5 W or Low 0 5 W heater range For Loop 2 allows selection of Heater On Off Refer to Paragraph 4 13 Heater Off Turns the heater off for Loop 1 or turns the control output off for Loop 2 Refer to Paragraph 4 13 LakeShore 331 Temperature Controller Control A Tune Remote 00000 0 222 00000 0000000 ee Control Zone Input Display Alarm Remote Escape Heater Setup Setting Setup Format Local H Range La C A PID Curve Analog Heater Setpoint Entry Math Output Interface Enter Loop Off aja eos Quo aa a A a en O e Reeg C331 1 1 eps Figure 4 1 Model 331 Front Panel Operation 4 1 Lake Shore Model 331 Temperature Controller User s Manual Keypad Definitions Continued Control Setup Setpoint Zone Settings PIDIMHP Input Setup Curve Entry Display Format Math Alarm Analog Output Remote Local Interface A v Escape Enter 0 9 Allows selection of control input setpoint units closed or open loop control mode power up enable display of heater output units setpoint ramp enable and ramp rate for the currently selected loop Refer to Paragraph 4 7 for control setup and Paragraph 4 12 for ramp feature Allows entry of control setpoint for the currently sel
42. Model 330 or 340 Temperature Controllers Jumper 4 for Input A and Jumper 7 for Input B are used to select the function of Pin 3 of the connectors The Model 330 provides a constant 1 mA sensor excitation current on Pin 3 and 10 pA current on Pin 5 The Model 340 provides both 1 mA and 10 yA excitation current on Pin 5 and connects Pin 3 to sensor ground reference If the sensor being used was wired for use with a Model 330 the jumper should be placed in the 330 position factory default This provides the output current selected via the front panel input setup function on both Pins 5 and 3 If the sensor was wired for use with a Model 340 the jumper should be placed in the 340 position This provides the output current on Pin 5 only and connect Pin 3 to sensor ground reference Pin Symbol Description E Gan Voltage 3 IN 1 mA Model 330 Configuration Shield Model 340 Configuration Voltage 6 None Shield SCS Figure 3 3 Diode Resistor Input Connector 3 4 Installation Lake Shore Model 331 Temperature Controller User s Manual 3 5 2 Sensor Lead Cable The sensor lead cable used outside the cooling system can be much different from what is used inside Between the instrument and vacuum shroud error and noise pick up need to be minimized not heat leak Larger conductor 22 to 28 AWG stranded copper wire is recommended because it has low resistance yet remains flexible when several wires are bundled in a cable
43. Model 331 are not able to read some sensors over their entire temperature range Lake Shore sells calibrated sensors that operate down to 50 millikelvin mK but the Model 331 is limited to above 1 K in its standard configuration Sensor Sensitivity Temperature sensor sensitivity is a measure of how much a sensor signal changes when the temperature changes It is an important sensor characteristic because so many measurement parameters are related to it Resolution accuracy noise floor and even control stability depend on sensitivity Many sensors have different sensitivities at different temperatures For example a platinum sensor has good sensitivity at higher temperatures but has limited use below 30 kelvin K because its sensitivity drops sharply It is difficult to determine if a sensor has adequate sensitivity over the experimental temperature range This manual has specifications Table 1 2 that include sensor sensitivity translated into temperature resolution and accuracy at different points This is typical sensor response and can be used as a guide when choosing a sensor to be used with the Model 331 Cooling System Design 2 1 Lake Shore Model 331 Temperature Controller User s Manual 2 2 2 2 1 Environmental Conditions The experimental environment is also important when choosing a sensor Environmental factors such as high vacuum magnetic field corrosive chemicals or even radiation can limit the use of some types of
44. Otherwise the Model 331 will operate in sensor units like ohms or volts The Model 331 may not work over the full temperature range of some sensors The standard inputs in are limited to operation above 1 K even with sensors that can be calibrated to 50 mK SoftCal SoftCal is a good solution for applications that do not require the accuracy of a traditional calibration The SoftCal algorithm uses the well behaved nature of sensors that follow a standard curve to improve the accuracy of individual sensors A few known temperature points are required to perform SoftCal Lake Shore sells SoftCal calibrated sensors that include both the large interpolation table and the smaller breakpoint interpolation table A CalCurve may be required to get the breakpoint table into a Model 331 where it is called a temperature response curve Refer to Paragraph 2 2 4 The Model 331 can also perform a SoftCal calibration The user must provide one two or three known temperature reference points The range and accuracy of the calibration is based on these points Refer to Paragraph 5 3 Standard Curves Some types of sensors behave in a very predictable manner and a standard temperature response curve can be created for them Standard curves are a convenient and inexpensive way to get reasonable temperature accuracy Sensors that have a standard curve are often used when interchangeability is important Some individual sensors are selected for their ability to m
45. Output Wiring icono A ea 3 8 3 7 4 Loop 1 Heater Output NoiSe arpei r e E det aR E E aiaa i apaa Eede ak Riaan aaa iaa 3 9 3 7 5 Loop 2 Output ie 3 9 3 7 6 Loop 2 Output RESIStanCe guddes e aii e 3 9 3 7 7 Loop Output Comme cto 3 9 3 7 8 Loop 2 Heater Protection cisnes 3 9 3 7 9 Boosting the Output Power 3 9 3 8 ANALOG OUTPUT rrai ida 3 10 3 9 RELAISE 3 10 3 10 INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE cooocccccnconcnonononononncncnanancnnnnnnncnnnannncnnnnnos 3 11 Ai OPERATION inicia rocas 4 1 4 0 GENERAL uti reos 4 1 4 1 FRONT PANEL DESCRIPTION cccocccccocccncccoconcnnnnnononannno nono nc cnn cc arrancan rana nnnnrran ranas 4 1 4 1 1 Keypad Dennitions it a ee 4 1 4 1 2 ANO Cd A ia 4 3 4 1 3 General Keypad Operation 4 3 4 1 4 Display Definition sa es 4 4 4 2 TURNING POWER ON viii ibas 4 4 4 3 DISPLAY FORMAT AND SOURCE UNITS GELECTION ecceeeeeeeeeeeeneeeeeeaeeeenneeeeeenaeeeeeeaas 4 5 4 4 INPUT SETUP ss sesh cacti cee sagittal a be dnt A ias 4 7 4 4 1 Diode Sensor Input Setup eege e eat iea e ibi 4 7 4 4 2 Resistor Sensor InpUESStU oeiee auii koeien trade 4 8 4 4 2 1 Thermal EMF Compensation sorosiane aridinio sete iaat diiad edian 4 8 4 4 3 Thermocouple Sensor Input Setup 4 9 4 4 3 1 Room Temperature Compensation nano cnn nro nnnn nan nn rr narrar rn rr nnn rra 4 9 4 4 3 2 Room Temperature Calibration Procedure sssssssseenssssssrnrrerssnsstttrrrnnsstnnnnnsnrtnnn nnns nnne nt 4 10 4 5 CURVE SELECTION
46. SETP lt loop gt lt value gt term Format n tnnnnnn lt loop gt Specifies which loop to configure lt value gt The value for the setpoint in whatever units the setpoint is using Example SETP 1 122 5 term Control Loop 1 setpoint is now 122 5 based on its units SETP Control Setpoint Query Input SETP lt loop gt term Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt value gt term Format nnnnnn SRDG Sensor Units Input Reading Query Input SRDG lt input gt term Format a lt input gt Specifies which input to query A or B Returned lt sensor units value gt term Format nnnnnn Remarks Also see the RDGST command 6 38 Remote Operation TEMP Input Returned Format Remarks TUNEST Input Returned Format ZONE Input Format Remarks Example ZONE Input Format Returned Format Lake Shore Model 331 Temperature Controller User s Manual Thermocouple Junction Temperature Query TEMP lt junction temperature gt term nnnnnnn Temperature is in kelvin Control Tuning Status Query TUNEST lt tuning status gt term n 0 no active tuning 1 active tuning Control Loop Zone Table Parameter Command ZONE lt loop gt lt zone gt lt top value gt lt P value gt lt I value gt lt D value gt lt mout value gt lt range gt term n nan znnnnnn tnnnnnn tnnnnnn tnnnnnn tnnnnnn n term lt loop gt Specifies which loo
47. Shore Model 331 Temperature Controller User s Manual AutoTuning Continued 2 9 When the user selects a new setpoint the Model 331 logs the change in temperature at the load and the change in heater output that was required to make the load temperature change The old control settings are used while data is being logged so a good initial guess of settings can improve the efficiency of the AutoTune feature Once the load temperature is at or near the new setpoint the Model 331 looks at the logged data to calculate the best P and D settings values Those values are then loaded and used as the control parameters so the control loop can stabilize at the new setpoint AutoTune does not function during a ramp because the dominant time constant of the load is disguised by the ramp rate The Tune LED blinks to indicate that tuning data is being logged The LED is illuminated but not blinking when the tuning process is complete The LED will not blink again until the user changes the setpoint If AutoTune does not give desired results the first time make a few small 2 to 5 degree changes in setpoint and let the Model 331 go until the Tune LED stops blinking In many cases AutoTune is able to arrive at a better set of control settings There are situations where AutoTune is not the answer The algorithm can be fooled when cooling systems are very fast very slow have a large thermal lag or have a nonlinear relationship between heater power an
48. also be manually controlled as a voltage source for any other application or used as the control output for Loop 2 The analog output is a variable DC voltage source that can vary from 10V to 10V The voltage is generated by a 16 bit D A converter with resolution of 0 3 mV or 0 003 of full scale The output is short circuit protected but should never be used to drive a resistance lower than 100 Q When acting as the Loop 2 heater the output can provide up to 1 W of power 0 1 A into a 100 Q minimum heater load For further specifications refer to the Loop 1 and 2 comparison table in Paragraph 1 3 The analog output has four modes of operation Off Input Manual and Loop 2 If you select Off the analog output is set to O volts and you are returned to the normal display Once a mode is selected the parameters associated with that mode follow on setting screens 4 16 1 Analog Output In Input Mode In Input mode the analog output will track the input according to scaling parameters entered by the user Press the Analog Output key Press the A or Y key until Input A is showing Press the Enter key Press the A or Y key to cycle through the data source units Temp K Temp C Sensor or Linear where K kelvin C Celsius Sensor volts V or ohms Q and Linear MX B or M X B refer to Paragraph 4 14 2 For this example choose Temp K Press the Enter key Press the A or Y key to toggle
49. an input its readings may also be displayed in temperature Table 4 2 Sensor Curves Curve Display Sensor Model Temperature For Data Points Number Type Number Range Refer To 01 DT 470 Silicon Diode DT 470 1 4 475 K Table D 1 02 DT 670 Silicon Diode DT 670 1 4 500 K Table D 2 03 DT 500 D Silicon Diode DT 500 D 1 4 365 K Table D 3 04 DT 500 E1 Silicon Diode DT 500 E1 1 1 330 K Table D 3 05 Reserved 06 PT 100 e GE PT 100 30 800K Table D 4 07 PT 1000 10009 Plat PT 1000 30 800 K Table D 4 08 RX 102A AA NTC RTD Rox RX 102A 0 05 40 K Table D 5 09 RX 202A AA NTC RTD Rox RX 202A 0 05 40 K Table D 6 10 Reserved 11 Reserved 12 Type K Thermo 25mV 8 50mV Type K 3 1645 K Table D 7 13 Type E Thermo 25mV 8 50mV Type E 3 1274 K Table D 8 14 Type T Thermo 25mV amp 50mV Type T 3 670 K Table D 9 15 AuFe 0 03 Thermo 25mV amp 50mV AuFe 0 03 3 5 500 K Table D 10 16 AuFe 0 07 Thermo 25mV amp 50mV AuFe 0 07 3 15 610K Table D 11 17 Reserved 18 Reserved 19 Reserved 20 Reserved 21 41 User Curves No longer sold by Lake Shore Operation 4 5 1 4 5 2 4 5 3 Lake Shore Model 331 Temperature Controller User s Manual Diode Sensor Curve Selection Once the input is setup for the Silicon or Gallium Aluminum Arsenide Diode Paragraph 4 4 1 you
50. and velocities of the molecules in a body are increased the temperature is increased whether the body is a solid liquid or gas Thermometers are used to measure temperature The temperature scale is based on the temperature at which ice liquid water and water vapor are all in equilibrium This temperature is called the triple point of water and is assigned the value 0 C 32 F and 273 15 K These three temperature scales are defined as follows Celsius Abbreviation C A temperature scale that registers the freezing point of water as 0 C and the boiling point as 100 C under normal atmospheric pressure Formerly known as Centigrade Originally devised by Anders Celsius 1701 1744 a Swedish astronomer Fahrenheit Abbreviation F A temperature scale that registers the freezing point of water as 32 F and the boiling point as 212 F under normal atmospheric pressure Originally devised by Gabriel Fahrenheit 1686 1736 a German physicist residing in Holland developed use of mercury in thermometry Kelvin Abbreviation K An absolute scale of temperature the zero point of which is approximately 273 15 C Scale units are equal in magnitude to Celsius degrees Originally devised by Lord Kelvin William Thompson 1824 1907 a British physicist mathematician and inventor COMPARISON The three temperature scales are graphically compared in Figure B 1 Boiling point of water 373 15 K 100 C 212 F Freezing point o
51. any of the user curve locations 21 thru 41 Press the Enter key You will see the following message Use the numerical keypad to enter the applicable sensor serial number to a maximum of 10 digits For this example we will enter 0123456789 Press the Enter key NOTE If Point 1 is not being used press the Enter key with both settings at their default value and advance to Point 2 Use the numerical keypad to enter the measured data point at or near the boiling point of helium 4 2 K Temperatures outside the range of 2 10 K are not permitted The message Invalid Point Please Reenter is displayed if either point is outside the acceptable range For this example we will enter 1 62999 Press the Enter key The cursor will jump to the temperature reading Again use numerical keypad to enter the temperature the measurement was taken at For this example we will enter 4 18 K Press the Enter key a Hr 5 10 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual SoftCal Calibration Curve Creation Continued NOTE If Point 2 is not being used press the Enter key with both settings at their default value and advance to Point 3 Use the numerical keypad to enter the measured data point at or near the boiling point of nitrogen 77 35 K Temperatures outside the range of 50 100 K are not permitted For this example we will enter 1 02111 Press the Enter key
52. between Bipolar Mode On or Off Operation 4 31 Lake Shore Model 331 Temperature Controller User s Manual Analog Output In Input Mode Continued Bipolar mode refers to whether or not negative voltages are used as shown below Lowest Pap Middle Highest Bipolar Mode On 10V output OV 10 V Input Mode Lowest Middle Put Highest Bipolar Mode Off 0 V 5 V Output 10 V For this first example we will choose Bipolar Mode On Press the Enter key The 10 V value is entered using the numeric keypad which includes the numbers 0 9 and decimal point For this example we will enter 0 K Press the Enter key The 10 V value is entered using the numeric keypad which includes the numbers 0 9 and decimal point For this example we will enter 100 K Press the Enter key You are returned to the normal display The analog output will now correspond to the input temperature as shown below For example if the actual reading was 50 K the analog output would be at 0 V middle of the scale OK Input 50 K 100 K Bipolar Mode On If we repeat the same procedure using all the same settings but select Bipolar Mode Off the output would be as shown below In this case if the actual reading was 50 K the analog output would be 5 V middle of the scale 0K Input 50 K 100 K Bipolar Mode Off 0 V Output 5 V 10 V 4 32 Operation Lake Shore Model 331 Temperature Controller User s Manual
53. can be an appreciable part of a low voltage sensor measurement The Model 331 can help with a thermal correction algorithm The instrument will automatically reverse the polarity of the current source every other reading The average of the positive and negative sensor readings will cancel the thermal EMF voltage which is present in the same polarity regardless of current direction To turn reversal on or off press the Input Setup key and press the Enter key until the following display appears Resistor sensors have the additional choice of turning current reversal On or Off with the default being Off If turned On the Model 331 will automatically reverse the polarity Press the Enter key Proceed to Paragraph 4 5 2 to select a temperature curve or press the Escape key to return to the normal display 4 8 Operation 4 4 3 4 4 3 1 Lake Shore Model 331 Temperature Controller User s Manual Thermocouple Sensor Input Setup Model 331X TX only The following thermocouple screens are only displayed when the Model 331 hardware is configured at the factory with one or two thermocouple sensor inputs being Model 331X T1 or T2 The user has the choice of two different input voltage ranges 25 mV and 50 mV The 25 mV range is recommended for cryogenic applications or higher temperatures less than 500 K Since thermocouple voltage can exceed 25 mV on some thermocouple types the 50 mV range is recommended for temperatu
54. commands EXAMPLE Input A Range 100Q Plat 250 Reversal Off Zero Offset Reset Command CALRSTZ A 2 Gain Reset Command CALRSTG A 2 3 Short all four terminals I I V V of the input together do not tie the terminals to ground 4 Via the interface obtain the input reading using the CALREAD command and record this number 5 Program the offset calibration by negating the value read in the previous step and providing it using the CALZ command EXAMPLE Input A Range 100Q Plat 250 Reversal Off CALREAD Reading 000 003 Calibration Command CALZ A 2 0 003 6 From Table 8 2 select the calibration resistor for the range being calibrated and use the DMM in 4 lead resistance measurement mode to measure the value of the resistor to the tolerance shown 7 Attach the calibration resistor to the Model 331 sensor input Be sure to connect the resistor using proper 4 lead connection techniques 8 Via the interface obtain the input reading using the CALREAD command and record this number 9 Program the gain calibration by dividing the actual resistance of the calibration resistor by the value read in the previous step and provide the result using the CALG command Note that the gain calibration constant will always be within 5 of 1 00000 EXAMPLE Input A Range 10012 Plat 250 Reversal Off Measured Value of Calibration Resistor 100 0250Q CALREAD Reading 100 145 Constant Calculation 100 0250 100 145 0 99880 Calibr
55. converter and separate current source for each input Sensors are optically isolated from other instrument functions for quiet and repeatable sensor measurements Sensor data from each input can be read up to ten times per second with display updates twice each second Standard temperature response curves for silicon diodes platinum RTDs and many thermocouples are included Up to twenty 200 point CalCurves for Lake Shore calibrated sensors or user curves can be loaded into non volatile memory via computer interface or the instrument front panel A built in SoftCal algorithm can also be used to generate curves for silicon diodes and platinum RTDs for storage as user curves Temperature Control The Model 331E offers one and Model 331S two proportional integral derivative PID control loops A PID control algorithm calculates control output based on temperature setpoint and feedback from the control sensor Wide tuning parameters accommodate most cryogenic cooling systems and many small high temperature ovens Control output is generated by a high resolution digital to analog converter for smooth continuous control The first control loop drives heater output Both versions also include manual control mode Heater output for the Models 331S and 331E is a well regulated variable DC current source Heater output is optically isolated from other circuits to reduce interference and ground loops Heater output can provide up to 50 W of continuous
56. fields GaAlAs diodes require calibration Platinum RTDs offer high uniform sensitivity from 30 to over 800 K with excellent reproducibility they are useful as a thermometry standard They follow a standard curve above 70 K and are interchangeable in many applications but are not useful at cryogenic temperatures below 20 K Rhodium Iron RTDs offer high stability and high resistance to ionizing radiation across a wide temperature range from 1 4 to 400 K with a linear response above 100 K They are not recommended for use in magnetic fields below 77 K Rhodium lron RTDs require calibration Cernox and High Temperature Cernox RTDs offer excellent sensitivity at low cryogenic temperatures with resistance to strong magnetic fields and ionizing radiation Sensitivity decreases at higher temperatures Cernox sensors require calibration Table 1 1 Temperature Range of Typical Lake Shore Sensors Diodes Model Useful Range Silicon Diodes DT 470 1 4 475K GaAlAs Diode TG 120 1 4 475K Positive Temperature Coefficient PTC RTDs 100 Q Platinum RTD PT 100 250 4 full scale 30 675 K 100 Q Platinum RTD PT 100 500 Q full scale 30 800 K Rhodium lron RTD RF 800 4 1 4 400 K Negative Temperature Coefficient NTC RTDs Germanium RTD GR 200A 1000 2 100K Germanium RTD GR 200A 250 1 2 40K Carbon Glass RTD CGR 1 500 3 325K Cernox RTD CX 1050 AA or SD 3 5 325 K Cer
57. for Loop 1 has several ranges that can improve resolution but its output is in current not voltage To use Loop 1 to program a larger power supply a programming resistor can be placed across the heater output to produce a programming voltage The programming voltage is related to output current by V program 7 R x program output The resistor must be chosen to convert a full scale current from the highest heater output range being used to the full scale programming voltage of the auxiliary supply For example if the auxiliary supply has a full scale programming voltage of 10 V and the maximum current for the highest heater output range being used is 0 3 A the programming resistor should be 10 V 0 3 A 33 Q The programming resistor must be rated for the power being dissipated in it which is 2xR Power outpu program or 3 W The Low heater output range can be selected to reduce the power dissipated in the programming resistor Installation 3 9 Lake Shore Model 331 Temperature Controller User s Manual 3 8 3 9 ANALOG OUTPUT Model 331S Only The Analog Output available on the rear panel of the Model 331S is a voltage output that can be used for monitor and control applications Their most basic function is a temperature monitor where it puts out a voltage that is proportional to temperature lt can be configured to monitor the output of a linear equation which allows the user to select an offset and gain The a
58. gt Specifies which input to query A or B Returned lt min value gt lt max value gt term Format nnnnnn nnnnnn Remarks Returns the minimum and maximum input data Also see the RDGST command MNMX Minimum and Maximum Input Function Parameter Command Input MNMX lt input gt lt source gt term Format a n lt input gt Specifies input to configure A or B lt source gt Specifies input data to process through max min Valid entries 1 kelvin 2 Celsius 3 sensor units 4 linear data Example MNMX B 3 term Input B min max function is on and processes data from the input sensor units reading 6 34 Remote Operation MNMX Input Format Returned Format Lake Shore Model 331 Temperature Controller User s Manual Minimum and Maximum Input Function Parameter Query MNMX lt input gt term a lt input gt Specifies which input to query A or B lt source gt term n Refer to command for description MNMXRST Minimum and Maximum Function Reset Command Input Remarks MODE Input Format Example MODE Input Returned Format MOUT Input Format Example MOUT Input Format Returned Format MNMXRST term Resets the minimum and maximum data for all inputs Remote Interface Mode Command MODE lt mode gt term n lt mode gt O local 1 remote 2 remote with local lockout MODE 2 term Places the Model 331 into remote mode with local lockout
59. instrument Previously called Precision Option calibrate To determine by measurement or comparison with a standard the correct value of each scale reading ona meter or other device or the correct value for each setting of a control knob cathode The terminal from which forward current flows to the external circuit Anode H Cathode Carbon Glass A temperature sensing material fabricated from a carbon impregnated glass matrix used to make the Lake Shore CGR family of sensors Celsius C Scale A temperature scale that registers the freezing point of water as O C and the boiling point as 100 C under normal atmospheric pressure Celsius degrees are purely derived units calculated from the Kelvin Thermodynamic Scale Formerly known as centigrade See Temperature for conversions Cernox A Lake Shore resistance temperature detector based on a ceramic oxy nitride resistance material CGR Carbon Glass Resistor cgs system of units A system in which the basic units are the centimeter gram and second Chebychev polynomials A family of orthogonal polynomials which solve Chebychev s differential equation Chebychev differential pe earan A special case of Gauss hypergeometric second order differential equation 1 x f x xP x n x Chromel A chromium nickel aie which comprises the positive lead of Type E and K thermocouples closed loop See feedback control system coercive forc
60. is configured at the factory with one or two thermocouple sensor inputs being Model 331X T1 or T2 Once the input is setup for the thermocouple input voltage Paragraph 4 4 3 you may choose a temperature curve Press the Input Setup key Standard curve numbers 12 thru 16 being relevant You are also given the choice of None You may also choose from any appropriate User Curves stored in Curve Numbers 21 thru 41 Data points for thermocouple curves are detailed in Tables D 7 thru D 11 in Appendix D Press the Enter key until you see the curve selection screen shown below Use the A or Y key to cycle through the sensor curves until the desired curve is displayed Press the Enter key to return to the normal display 4 12 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 6 TEMPERATURE CONTROL There are many steps involved in setting up a temperature control loop Chapter 2 of this manual describes the principals of closed loop feedback control Chapter 3 describes necessary hardware installation The following sections of this chapter describe how to operate the control features and set control parameters Each control parameter should be considered before enabling a control loop or the instrument may not be able to perform the most simple control functions A good starting point is deciding which control loop to use whether to operate in open or closed control mode and which tuning mode is best
61. may choose a temperature curve Standard curve numbers 1 thru 4 being relevant choices You are also given the choice of None You may also choose from any appropriate User Curves stored in Curve Numbers 21 thru 41 Data points for standard diode curves are detailed in Tables D 1 thru D 3 in Appendix D Press the Input Setup key Press the Enter key until you see the curve selection screen shown below Use the A or Y key to cycle through the sensor curves until the desired curve is displayed Press the Enter key to return to the normal display Resistor Sensor Curve Selection Once the input is setup for the Platinum Rhodium lron or various NTC RTD sensors Paragraph 4 4 2 you may choose a temperature curve Standard curve numbers 6 and 7 being relevant to Platinum or curves 8 and 9 being relevant to Rox sensors You are also given the choice of None You may also choose from any appropriate User Curves stored in Curve Numbers 21 thru 41 Data points for resistor curves are detailed in Tables D 4 thru D 6 in Appendix D Press the Input Setup key Press the Enter key until you see the curve selection screen shown below Es 1628 AR Use the A or Y key to cycle through the sensor curves until the desired curve is displayed Press the Enter key to return to the normal display Thermocouple Sensor Curve Selection The following thermocouple screens are only displayed when the Model 331 hardware
62. must be wired to Pin 2 on the other used for receive Cables that swap the complementing lines are called null modem cables and must be used between two DTE wired devices Null modem adapters are also available for use with straight through cables Paragraph 8 4 1 illustrates suggested cables that can be used between the instrument and common computers The instrument uses drivers to generate the transmission voltage levels required by the RS 232C standard These voltages are considered safe under normal operating conditions because of their relatively low voltage and current limits The drivers are designed to work with cables up to 50 feet in length 6 2 2 Hardware Support The Model 331 interface hardware supports the following features Asynchronous timing is used for the individual bit data within a character This timing requires start and stop bits as part of each character so the transmitter and receiver can resynchronized between each character Half duplex transmission allows the instrument to be either a transmitter or a receiver of data but not at the same time Communication speeds of 300 1200 or 9600 Baud are supported The Baud rate is the only interface parameter that can be changed by the user Hardware handshaking is not supported by the instrument Handshaking is often used to guarantee that data message strings do not collide and that no data is transmitted before the receiver is ready In this instrument appropriate software ti
63. ohmmeter Do not rely on visual inspection of fuse 1 Locate line input assembly on the instrument rear panel See Figure 8 1 Turn power switch Off O 2 3 Remove instrument power cord 4 With a small screwdriver release the drawer holding the line voltage selector and fuse 8 2 Service Lake Shore Model 331 Temperature Controller User s Manual 5 Remove existing fuse s Replace with proper Slow Blow time delay fuse ratings as follows 100 120V 15AT250V 0 25x 1 25 inches 220 240VW 0 75AT250V 5x20 mm Re assemble line input assembly in reverse order Verify voltage indicator in the line input assembly window Connect instrument power cord o gt Turn power switch On I 8 4 REAR PANEL CONNECTOR DEFINITIONS The Sensor Input Heater Output Relays and Analog Output and RS 232 connectors are defined in Figures 8 2 thru 8 5 For thermocouple connector details refer to Figure 3 4 C331 8 2 eps Description Current Voltage 1 mA Model 330 Configuration Shield Model 340 Configuration Refer to Paragraph 8 8 for jumper settings that determine the output of this pin and to Paragraph 3 5 1 for a general explanation Voltage Current 6 None Shield Figure 8 2 Sensor INPUT A and B Connector Details HEATER OUTPUT HI LO C 331 8 3 eps HI Banana LO Banana Ground Banana Figure 8 3 HEATER OUTPUT Connector Details Service 8 3 Lake Sho
64. process until the load warms up to room temperature Do not leave the system unattended the heater may have to be turned off manually to prevent overheating If the load never reaches room temperature some adjustment may be needed in heater resistance or load The list of heater range versus load temperature is a good reference for selection the proper heater range It is common for systems to require two or more heater ranges for good control over their full temperature Lower heater ranges are normally needed for lower temperature The Model 331 is of no use controlling at or below the temperature reached when the heater was off Many systems can be tuned to control within a degree or two above that temperature Tuning Proportional The proportional setting is so closely tied to heater range that they can be thought of as fine and course adjustments of the same setting An appropriate heater range must be known before moving on to the proportional setting Begin this part of the tuning process by letting the cooling system cool and stabilize with the heater off Place the Model 331 in closed loop control mode with manual PID tuning then turn integral derivative and manual output settings off Enter a setpoint several degrees above the cooling systems lowest temperature Enter a low proportional setting of approximately 5 or 10 and then enter the appropriate heater range as described above The heater display should show a value greater than zero
65. produce and implement these programs not included with the instrument the concepts illustrated apply to almost any application where these tools are available IEEE 488 Interface Board Installation for Visual Basic Program This procedure works for Plug and Play GPIB Hardware and Software for Windows 98 95 This example uses the AT GPIB TNT GPIB card 1 Install the GPIB Plug and Play Software and Hardware using National Instruments instructions 2 Verify that the following files have been installed to the Windows System folder a gpib 32 dll b gpib dll c gpib32ft dll Files b and c will support 16 bit Windows GPIB applications if any are being used 3 Locate the following files and make note of their location These files will be used during the development process of a Visual Basic program a Niglobal bas b Vbib 32 bas NOTE If the files in Steps 2 and 3 are not installed on your computer they may be copied from your National Instruments setup disks or they may be downloaded from www natinst com 4 Configure the GPIB by selecting the System icon in the Windows 98 95 Control Panel located under Settings on the Start Menu Configure the GPIB Settings as shown in Figure 6 1 Configure the DEV12 Device Template as shown in Figure 6 2 Be sure to check the Readdress box Remote Operation 6 5 Lake Shore Model 331 Temperature Controller User s Manual System Properties 2 x General Device Manager Hardware Profiles Perfor
66. provided by the internal temperature sensor when compensation is on No Use the room temperature calibration value determined the last time the room temperature calibration procedure was performed Yes Perform the room temperature calibration procedure that follows Calibration Procedure 1 Attach a thermocouple sensor or direct short across the input terminals of the thermocouple input See Figure 3 4 for polarity 2 Place the instrument away from drafts If calibrating using a short place an accurate room temperature thermometer near the terminal block 3 Allow the instrument to warm up for at least Y hour without moving or handling the sensor If calibrating with a short skip to step 6 otherwise insert the thermocouple into the ice bath liquid nitrogen helium dewar or other know fixed temperature The temperature should be close to the measurement temperature that requires best accuracy 5 Read the displayed temperature If the temperature display is not as expected check to be sure that the thermocouple is making good thermal contact If possible add a thermal mass to the end of the thermocouple 6 Press the Input Setup key and press the Enter key until the Room Cal screen appears Press the A or Y key until the Yes selection appears then press the Enter key sn E T Enter the true temperature that the thermocouple should read If input is shorted then enter the actual
67. remains in the normal state On Manual On Relay remains in the active state AAlarm Relay will follow Input A alarms Both Alarms Relay active when either the High or Low Alarm is active Low Alarms Relay active only when the Low Alarm is active High Alarms Relay active only when the High Alarm is active B Alarm Relay will follow Input B alarms Both Alarms Relay active when either the High or Low Alarm is active Low Alarms Relay active only when the Low Alarm is active High Alarms Relay active only when the High Alarm is active Figure 4 6 Relay Settings To configure Relay 1 press the Alarm key and press Enter until the following display appears Use the A or Y key to cycle through the options for Relay 1 Off On A Alarm or B Alarm Press the Enter key If the relay is set to follow either the A or B Alarm the following screen will appear Fe Use the A or Y key to cycle through the relay alarm functions Low Alarm High Alarm and Both Alarms Press the Enter key Configuration for Relay 2 is identical to Relay 1 4 30 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 16 ANALOG OUTPUT Model 331S Only The Model 331S has a single analog output on Pins 7 and 8 of the terminal block at the rear of the instrument It is normally configured to send a voltage proportional to temperature to a strip chart recorder or separate data acquisition system The output can
68. state gt term Format n n lt high state gt 0 Off 1 On lt low state gt 0 Off 1 On 6 26 Remote Operation ALMRST Input Remarks ANALOG Input Format Example Lake Shore Model 331 Temperature Controller User s Manual Reset Alarm Status Command ALMRST term Clears both the high and low status of all alarms including latching alarms Analog Output Parameter Command ANALOG lt bipolar enable gt lt mode gt lt input gt lt source gt lt high value gt lt low value gt lt manual value gt term n n a n znnnnnn znnnnnn znnnnnn lt bipolar enable gt Specifies analog output is 0 positive output only or 1 bipolar lt mode gt Specifies data the analog output monitors Valid entries O off 1 input 2 manual 3 loop lt input gt Specifies which input to monitor if lt mode gt 1 lt source gt Specifies input data Valid entries 1 kelvin 2 Celsius 3 sensor units 4 linear equation lt high value gt If lt mode gt is 1 this parameter represents the data at which the analog output reaches 100 output lt low value gt If lt mode gt is 1 this parameter represents the data at which the analog output reaches 100 output if bipolar or 0 output if positive only lt manual value gt If lt mode gt is 2 this parameter is the output of the analog output ANALOG 0 1 A 1 100 0 0 0 term Sets analog output to monitor Input A kelvin reading with 100 0 K at 1
69. such as niobium tin Nb3Sn it is capable of generating magnetic fields of 100 000 oersteds and more with no steady power dissipation See electromagnet susceptance In electrical terms susceptance is defined as the reciprocal of reactance and the imaginary part of the complex representation of admittance suscept ibility conduct ance Glossary of Terminology A 7 Lake Shore Model 331 Temperature Controller User s Manual susceptibility x Parameter giving an indication of the response of a material to an applied magnetic field The susceptibility is the ratio of the magnetization M to the applied field H x M H In both SI units and cgs units the volume susceptibility is a dimensionless parameter Multiply the cgs susceptibility by 4r to yield the Sl susceptibility See also Initial Susceptibility and Differential Susceptibility As in the case of magnetization the susceptibility is often seen expressed as a mass susceptibility or a molar susceptibility depending upon how M is expressed temperature scales See Kelvin Scale Celsius Scale and ITS 90 Proper metric usage requires that only kelvin and degrees Celsius be used However since degrees Fahrenheit is in such common use all three scales are delineated as follows Boiling point of water 373 15 K 100 C 212 F Triple point of water 273 16 K Freezing point of water 273 15 K 0 C 32 F Absolute zero OK 273 15 C 459 67 F kelvin Celsius Fahrenheit To convert
70. symbol CalCurve Carbon Glass Cernox Duo Twist High Temperature Cernox Quad Lead Quad Twist Rox SoftCal and Thermox are trademarks of Lake Shore Cryotronics Inc MS DOS and Windows 95 98 NT are trademarks of Microsoft Corporation NI 488 2 is a trademark of National Instruments PC XT AT and PS 2 are trademarks of IBM Copyright 2000 2002 by Lake Shore Cryotronics Inc All rights reserved No portion of this manual may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the express written permission of Lake Shore Lake Shore Model 331 Temperature Controller User s Manual DECLARATION OF CONFORMITY d We Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville OH 43082 8888 USA hereby declare that the equipment specified conforms to the following Directives and Standards Application of Council Directives eee 73 23 EEC 89 336 EEC Standards to which Conformity is declared EN61010 1 Overvoltage Il Pollution Degree 2 EN61326 Class A Annex B Laka e 2 200 Signature Date Michael S Swartz Printed Name Vice President of Research and Development Position Lake Shore Model 331 Temperature Controller User s Manual Electromagnetic Compatibility EMC for the Model 331 Temperature Controller Electromagnetic
71. terminators must be set from the front panel before communication with the instrument can be established Other interface parameters can be set with device specific commands using the interface Paragraph 6 3 Press the Interface key The first screen is for selecting the Serial Interface Baud Rate and can be skipped by pressing the Enter key The Address screen is then displayed as follows Press the A or Y keys to increment or decrement the IEEE Address to the desired number Valid addresses are 1 thru 30 Default is 12 Press Enter to accept new number or Escape to retain the existing number Pressing Enter displays the Terminators screen Press the A or Y keys to cycle through the following Terminator choices CR LF LF CR LF and EOI The default is Cr Lf To accept changes or the currently displayed setting push Enter To cancel changes push Escape IEEE 488 Command Structure The Model 331 supports several command types These commands are divided into three groups 1 Bus Control Refer to Paragraph 6 1 2 1 a Universal 1 Uniline 2 Multiline b Addressed Bus Control 2 Common Refer to Paragraph 6 1 2 2 Device Specific Refer to Paragraph 6 1 2 3 4 Message Strings Refer to Paragraph 6 1 2 4 Di Bus Control Commande A Universal Command addresses all devices on the bus Universal Commands include Uniline and Multiline Commands A Uniline Command Message asserts only a single
72. to accept the new setting then the Escape key to return to the normal display Setting Manual Heater Power MHP Output Manual Heater Power MHP output is a manual setting of control output It can function in two different ways depending on control mode In open loop control mode the MHP output is the only output to the load The user can directly set control output from the front panel or over computer interface In closed loop control mode the MHP output is added directly to the output of the PID control equation In effect the control equation operates about the MHP output setting Manual heater power output setting is in percent of full scale When using the heater on Loop 1 percent of full scale is defined as percent of full scale current or power on the selected heater range Manual heater power output setting range is 0 to 100 with a resolution of 0 001 When using Loop 2 analog voltage output the setting range is 0 to 100 and resolution is 0 001 but the actual resolution of the output is only 0 003 To enter a MHP Output setting press the PID MHP key and press Enter until the following display appears The MHP Output setting is entered using the numeric keypad which includes the numbers 0 9 and decimal point Press the Enter key then the Escape key to return to the normal display Operation 4 17 4 9 Lake Shore Model 331 Temperature Controller User s Manual AUTO TUNE Closed Loop PID Cont
73. type to query 1 Low Alarm or 1 High Alarm lt status gt term n O Off 1 On Remote Operation 6 37 Lake Shore Model 331 Temperature Controller User s Manual REV Input Firmware Revision Query Input REV term Returned lt revision gt term Format n n Remarks Returns the version number of the input firmware installed in the instrument SCAL Generate SoftCal Curve Command Input SCAL lt std gt lt dest gt lt SN gt lt T1 value gt lt Ul value gt lt T2 value gt lt U2 value gt lt T3 value gt lt U3 value gt term Format n nn aaaaaaaaaa tnnnnn tnnnnn tnnnnn tnnnnn tnnnnn znnnnn lt std gt Specifies the standard curve to generate a SoftCal from Valid entries 1 6 7 lt dest gt Specifies the user curve to store the SoftCal curve Valid entries 21 41 lt SN gt Specifies the curve serial number Limited to 10 characters lt T1 value gt Specifies first temperature point lt U1 value gt Specifies first sensor units point lt T2 value gt Specifies second temperature point lt U2 value gt Specifies second sensor units point lt T3 value gt Specifies third temperature point lt U3 value gt Specifies third sensor units point Remarks Generates a SoftCal curve Refer to Paragraph 5 3 Example SCAL 1 21 1234567890 4 2 1 6260 77 32 1 0205 300 0 0 5189 term Generates a three point SoftCal curve from standard curve 1 and saves it in user curve 21 SETP Control Setpoint Command Input
74. unit of the magnetomotive force required to produce one maxwell of magnetic flux in a magnetic circuit of unit reluctance One gilbert is equal to 10 41 ampere turn Named for William Gilbert 1540 1603 an English physicist hypothesized that the earth is a magnet gilbert per centimeter Practical cgs unit of magnet intensity Gilberts per cm are the same as oersteds Greek alphabet The Greek alphabet is defined as follows Alpha Oo A lota 1 I Rho p P Beta B B Kappa K K Sigma O z Gamma Y T Lambda A A Tau T T Delta A Mu u M Upsilon v Y Epsilon e E Nu v N Phi d di Zeta E Z Xi E E Chi H X Eta n H Omicron O Psi y Y Theta 0 e Pi T II Omega 0 Q ground A conducting connection whether intentional or accidental by which an electric circuit or equipment is connected to the earth or to some conducting body of relatively large extent that serves in place of the earth Note It is used for establishing and maintaining the potential of the earth or of the conducting body or approximately that potential on conductors connected to it and for conducting ground current to and from the earth or of the conducting body H Symbol for magnetic field strength See Magnetic Field Strength Hall effect The generation of an electric potential perpendicular to both an electric current flowing along a thin conducting material and an external magnetic field applied at right angles to the current Named for Edwin H Hall 1855 1938 an American ph
75. used to label components as ESDS so A Es Handling Electrostatic Discharge Sensitive Components Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and everything that contacts it to ground potential by providing a conductive surface and discharge paths As a minimum observe these precautions 1 De energize or disconnect all power and signal sources and loads used with unit Place unit on a grounded conductive work surface 3 Ground technician through a conductive wrist strap or other device using 1 MQ series resistor to protect operator 4 Ground any tools such as soldering equipment that will contact unit Contact with operator s hands provides a sufficient ground for tools that are otherwise electrically isolated 5 Place ESDS devices and assemblies removed from a unit on a conductive work surface or in a conductive container An operator inserting or removing a device or assembly from a container must maintain contact with a conductive portion of the container Use only plastic bags approved for storage of ESD material 6 Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested Service 8 1 Lake Shore Model 331 Temperature Controller User s Manual 8 2 LINE VOLTAGE SELECTION Use the following procedure to change the instrument line voltage selector Verify the fuse value whenever line voltage is changed
76. where 100 seconds Start with a setting of 50 to 100 Again do not be afraid to make some small setpoint changes halving or doubling this setting to watch the affect Expect positive setpoint changes to react differently from negative setpoint changes AUTOTUNING Choosing appropriate PID control settings can be tedious Systems can take several minutes to complete a setpoint change making it difficult to watch the display for oscillation periods and signs of instability With the AutoTune feature the Model 331 automates the tuning process by measuring system characteristics and along with some assumptions about typical cryogenic systems computes setting values for P and D AutoTune works only with one control loop at a time and does not set the manual heater power output or heater range Setting an inappropriate heater range is potentially dangerous to some loads so the Model 331 does not attempt to automate that step of the tuning process When the AutoTune mode is selected the Model 331 evaluates the control loop similar to the manual tuning section described in Paragraph 2 7 One difference is that the Model 331 does not initiate changes to control settings or setpoint for the purpose of tuning t only gathers data and changes control settings after the user changes the setpoint Unexpected or unwanted disturbances to the control system can ruin experimental data being taken by the user Cooling System Design 2 13 Lake
77. 0 mA of current For the maximum of 1 W output power use a 100 Q resistive heater with a power rating greater than 1 W Smaller resistance values should not be used but larger resistances can be used for lower power applications Loop 2 Output Connector The connector for the Loop 2 output is on the RELAYS and ANALOG OUTPUT Terminal Block See Pins 7 and 8 in Figure 3 5 Twisted pair of small gauge wire is recommended Loop 2 Heater Protection The output is short protected so the instrument is not harmed if the heater resistance is too small It is not recommended because the additional load on instrument power supplies causes noise on internal circuits The second control loop has fewer features than the first including software protection and limits The user must be careful to build a robust system and account for the voltage range and power up state of the control output Boosting Output Power There are temperature control systems that require more power than the Model 331 can provide An auxiliary DC power supply can be used to boost the output of the Model 331 Programmable power supplies are available that use a low current programming voltage as an input to control a high current voltage output Analog Voltage Output used for Loop 2 output provides an ideal programming voltage for an auxiliary power supply The only drawback with using the analog output to program auxiliary supplies is it only has one voltage range The heater output
78. 00 output 10 0 V and 0 0 K at 0 output 0 0 V ANALOG Analog Output Parameter Query Input Returned Format AOUT Input Returned Format Remarks BEEP Input Format Remarks BEEP Input Returned Format ANALOG term lt bipolar enable gt lt mode gt lt input gt lt source gt lt high value gt lt low value gt lt manual value gt term n n a n tnnnnnn nnnnnn tnnnnnn Refer to command for definition Analog Output Data Query AOUT term lt analog output gt term nnn n Returns the percentage of output of the analog output Most often used for input or loop modes when the output value is set by the instrument Resolution is 0 5 Alarm Beeper Command BEEP lt state gt term n lt state gt O Off 1 On Enables or disables system beeper sound when an alarm condition is met Alarm Beeper Query BEEP lt state gt term n Refer to command for description Remote Operation 6 27 Lake Shore Model 331 Temperature Controller User s Manual BRIGT Display Brightness Command Input BRIGT lt bright gt term Format n lt bright gt 0 25 1 50 2 75 3 100 Default 2 BRIGT Display Brightness Query Input BRIGT term Returned lt bright gt term Format n Refer to command for description CMODE Control Loop Mode Command Input CMODE lt loop gt lt mode gt term Format n n lt loop gt Specifies which loop to configure 1 or 2 lt mode
79. 00 0 148 652 400 0 1486 52 21 445 0 165 466 445 0 1654 66 22 490 0 182 035 490 0 1820 35 23 535 0 198 386 535 0 1983 86 24 585 0 216 256 585 0 2162 56 25 630 0 232 106 630 0 2321 06 26 675 0 247 712 675 0 2477 12 27 715 0 261 391 715 0 2613 91 28 760 0 276 566 760 0 2765 66 29 800 0 289 830 800 0 2898 30 Curve Tables D 3 Lake Shore Model 331 Temperature Controller User s Manual Table D 5 Lake Shore RX 102A Rox Curve Break Temp Break Temp Break Temp point log Sg point lege Sg point logo K 1 3 02081 40 0 36 3 05186 13 50 71 3 17838 2 96 2 3 02133 38 8 37 3 05322 13 10 72 3 18540 2 81 3 3 02184 37 7 38 3 05466 12 70 73 3 19253 2 67 4 3 02237 36 6 39 3 05618 12 30 74 3 20027 2 53 5 3 02294 35 5 40 3 05780 11 90 75 3 20875 2 39 6 3 02353 34 4 41 3 05952 11 50 76 3 21736 2 26 7 3 02411 33 4 42 3 06135 11 10 17 3 22675 2 13 8 3 02472 32 4 43 3 06330 10 70 78 3 23707 2 00 9 3 02537 31 4 44 3 06537 10 30 79 3 24842 1 87 10 3 02605 30 4 45 3 06760 9 90 80 3 26000 1 75 11 3 02679 29 4 46 3 06968 9 55 81 3 27169 1 64 12 3 02749 28 5 47 3 07190 9 20 82 3 28462 1 53 13 3 02823 27 6 48 3 07428 8 85 83 3 29779 1 43 14 3 02903 26 7 49 3 07685 8 50 84 3 31256 1 33 15 3 02988 25 8 50 3 07922 8 20 85 3 32938 1 23 16 3 03078 24 9 51 3 08175 7 90 86 3 34846 1 130 17 3 03176 24 0 52 3 08447 7 60 87 3 37196 1 020 18 3 03280 23 1 53 3 08786 7 25 88 3 39220 0 935 19 3 03393 22 2 54 3 09150 6 90 89 3 41621 0 850 20 3 0
80. 00 kQ Miscellaneous e Dummy loads for warm up 1 each for Diode Resistor inputs 6 pin DIN 240 connectors plug with 100 kQ resistors configured for 4 lead measurement Calibration cable with 100 kQ standard can be used Short length of uninsulated wire 1 each for Thermocouple inputs Diode Resistor Sensor Input Calibration NOTE The thermocouple input calibration procedure in provided in Paragraph 8 9 3 Overview Each sensor input requires calibration Sensor Inputs contain a current source which can supply 10 yA or 1 mA of current only the 10 yA current sources are calibrated They are calibrated by adjusting pots on the Model 331 Main Board The sensor inputs contain multiple gain stages to accommodate the various sensors the Model 331 supports The input circuitry is not adjusted during calibration Instead precision voltages and resistors are attached to each input and mathematical calibration constants are calculated and programmed into the Model 331 Constants are stored to compensate for both input offset and gain errors Calibration Process Sensor Input Calibration Setup and Serial Communication Verification Allow the Model 331 to warm up for at least one hour with 100 kQ resistors attached to all inputs configured as diode resistor and all thermocouple inputs shorted Connect the Model 331 to the PC via the serial port Verify operation of serial communication by sending the IDN command and receiving the proper re
81. 044070 39 60 91 2 638010 198 00 146 11 3664 511 50 37 6 025470 41 40 92 2 512340 202 00 147 11 8098 519 50 38 6 006200 43 20 93 2 384920 206 00 148 12 2564 527 50 39 5 986280 45 00 94 2 255770 210 00 149 12 7342 536 00 40 5 965730 46 80 95 2 124900 214 00 150 13 2155 544 50 41 5 942210 48 80 96 1 992320 218 00 151 13 7 553 00 42 5 917930 50 80 97 1 858060 222 00 152 14 1879 561 50 43 5 892970 52 80 98 1 705090 226 50 153 14 7079 570 50 44 5 864730 55 00 99 1 549970 231 00 154 15 2314 579 50 45 5 835680 57 20 100 1 392820 235 50 155 15 7583 588 50 46 5 805860 59 40 101 1 233640 240 00 156 16 2887 597 50 47 5 776670 61 50 102 1 072450 244 50 157 16 8224 606 50 48 5 741100 64 00 103 0 909257 249 00 158 17 3594 615 50 49 5 704560 66 50 104 0 744065 253 50 159 17 9297 625 00 50 5 667130 69 00 105 0 576893 258 00 160 18 5037 634 50 51 5 628800 71 50 106 0 407776 262 50 161 19 1116 644 50 52 5 589590 74 00 107 0 217705 267 50 162 19 7538 655 00 53 5 549510 76 50 108 0 025325 272 50 163 20 4611 666 50 54 5 508560 79 00 109 0 188573 278 00 164 20 8627 673 00 55 5 466760 81 50 110 0 404639 283 50 D 8 Curve Tables Lake Shore Model 331 Temperature Controller User s Manual Table D 10 Chromel AuFe0 03 Thermocouple Curve Breakpoint mV Temp K Breakpoint mV Temp K 1 4 6667 3 5 32 2 24537 160 2 4 62838 6 35 33 2 06041 170 3 4 60347 8 15 34 1 86182 1
82. 1 6 245590 9 10 66 4 889610 112 00 121 2 946550 344 00 12 6 243040 9 95 67 4 826300 115 00 122 3 192800 349 50 13 6 240300 10 80 68 4 761840 118 00 123 3 441440 355 00 14 6 237210 11 70 69 4 696250 121 00 124 3 715300 361 00 15 6 233710 12 65 70 4 629530 124 00 125 3 991980 367 00 16 6 229800 13 65 71 4 561670 127 00 126 4 271300 373 00 17 6 225630 14 65 72 4 492700 130 00 127 4 553250 379 00 18 6 221000 15 70 73 4 422610 133 00 128 4 837770 385 00 19 6 215860 16 80 74 4 351390 136 00 129 5 148790 391 50 20 6 210430 17 90 75 4 266950 139 50 130 5 462770 398 00 21 6 204430 19 05 76 4 180930 143 00 131 5 779560 404 50 22 6 198680 20 10 77 4 093440 146 50 132 6 099160 411 00 23 6 191780 21 30 78 4 004430 150 00 133 6 421500 417 50 24 6 184530 22 50 79 3 913940 153 50 134 6 746540 424 00 25 6 176930 23 70 80 3 821970 157 00 135 7 099510 431 00 26 6 168310 25 00 81 3 728520 160 50 136 7 455590 438 00 27 6 159280 26 30 82 3 633620 164 00 137 7 814630 445 00 28 6 149830 27 60 83 3 537260 167 50 138 8 176630 452 00 29 6 139220 29 00 84 3 439460 171 00 139 8 541540 459 00 30 6 128130 30 40 85 3 340240 174 50 140 8 909320 466 00 31 6 116580 31 80 86 3 239610 178 00 141 9 306450 473 50 32 6 103700 33 30 87 3 122930 182 00 142 9 706830 481 00 33 6 090300 34 80 88 3 004370 186 00 143 10 1103 488 50 34 6 075460 36 40 89 2 884040 190 00 144 10 5169 496 00 35 6 060040 38 00 90 2 761910 194 00 145 10 9264 503 50 36 6
83. 1 Else ZeroCount 0 strHold frmSerial MSComml Input strReturn strReturn strHold End If Wend If strReturn lt gt Then strReturn Mid strReturn 1 Else strReturn No Response End If frmSerial txtResponse Text strHold ZeroCount 0 End If Loop End Sub Used to return response Temporary character space Terminators Counter used for Timing out Data string sent to instrument Show main window Terminators are lt CR gt lt LF gt Initialize counter Clear return string Clear holding string Close serial port to change settings Example of Comm 1 Example of 9600 Baud Parity Data Stop Read one character at a time Open port Wait loop Give up processor to other events Loop until Send button pressed Set Flag as false Get Command Clear response display Set all characters to upper case Get out on EXIT Send command to instrument Check to see if query Wait for response Add 1 to timeout if no character Wait for 10 millisecond timer False Timeout at 2 seconds Reset timeout for each character Read in one character Add next character to string Get characters until terminators Check if string empty Term 1 Strip terminators Send No Response Put response in textbox on main form Reset holding string Reset timeout counter Private Sub Timerl Timer frmSerial Timerl Enabled End Sub False Routine to handle Timer interrupt
84. 10 8 9 2 Diode Resistor Sensor Input Calbratton nano nn nr nono cnn narrar rr 8 11 8 9 3 Thermocouple Sensor Input Calibration o o oocconnnncnnniccnnnonccccnnnannno nono nonn non nn nano nnn nr naar nn rra nnnnnnns 8 14 8 9 4 Analog Output CalibratiON dese ee lcd 8 15 8 9 5 Calibration Specific Interface Commandes 8 16 APPENDIX A GLOSSARY OF TERMINOLOGY cconnccconnoccconnccccnnnnnninnnrninccr rre A 1 APPENDIX B TEMPERATURE SCALES onmccinccccnnnnnncnnnccinnscrrnnnrccrnrer rr B 1 APPENDIX C HANDLING OF LIQUID HELIUM AND NITROGEN cc ceeceseeseseeeeseeneeeeseeseeseeeeseseeeseeeseenenssneeeeenees C 1 APPENDIX D CURVE TABLES iii e a a iia acia D 1 iv Table of Contents Figure No 1 1 2 1 2 2 2 3 3 1 3 2 3 3 3 4 3 5 4 1 4 2 4 3 4 4 4 5 4 6 5 1 5 2 6 1 6 2 6 3 7 1 7 2 7 3 7 4 8 1 8 2 8 3 8 4 8 5 8 6 8 7 B 1 C 1 Lake Shore Model 331 Temperature Controller User s Manual LIST OF ILLUSTRATIONS Title Page Model 331 Temperature Controller Front Panel 1 1 Silicon Diode Sensor Calibrations and CalCurve ooooocincococcnonoccnonononcnnnonnncnnno cnn nnnnn cnn naar rr rr naar ran nn nrnnn rra 2 4 Typical Sensor Installation In A Mechanical HRetigerator A 2 6 Examples of PID COMON comica id a 2 11 Model 331 Rear Panel iirin iiie oni A a tad 3 2 Line Input Assembly iii at 3 3 Diode Resistor Input Connector c c c ca iba 3 4 Thermocouple Input Definition and Common Connector Polar
85. 100 K High Alarm Activated High Alarm Setpoint Temperature Reading Alarm Latching Off Deadband 5 K 55K Low Alarm Setpoint 50 K Low Alarm Activated Low Alarm Deactivated Figure 4 5 Deadband Example To begin alarm setup press the Alarm key With A Use the A or Y key to toggle between Input A and B Press the Enter key 4 28 Operation Lake Shore Model 331 Temperature Controller User s Manual Alarms Continued Use the A or WV key to Use the A or Y key to cycle through the following data sources Temp C Temp K Linear or Sensor where Temp C degrees Celsius Temp K kelvin Linear MX B or M X B refer to Paragraph 4 14 2 or Sensor volts V millivolts mV or ohms Q Press the Enter key The Low Alarm Point is entered using the numeric keypad which includes the numbers 0 9 and decimal point For this example enter 50 K Press the Enter key L tik The High Alarm Point is entered using the numeric keypad which includes the numbers 0 9 and decimal point For this example enter 100 K Press the Enter key ss y i H AT ps pa gie Use the A or Y key to toggle between Latching On or Off For this example select Alarm Latching Off Press the Enter key The dead band is entered using the numeric keypad which includes the numbers 0 9 and decimal poi
86. 23 Lake Shore Model 331 Temperature Controller User s Manual 6 3 1 Interface Commands Alphabetical Listing CLS Clear Interface Command Input CLS term Remarks Clears the bits in the Status Byte Register and Standard Event Status Register and terminates all pending operations Clears the interface but not the controller The related controller command is RST ESE Event Status Enable Register Command Input ESE lt bit weighting gt term Format nnn Remarks Each bit is assigned a bit weighting and represents the enable disable mask of the corresponding event flag bit in the Standard Event Status Register To enable an event flag bit send the command ESE with the sum of the bit weighting for each desired bit Refer to Paragraph 6 1 3 2 for a list of event flags Example To enable event flags 0 3 4 and 7 send the command ESE 143 term 143 is the sum of the bit weighting for each bit Bit Bit Weighting Event Name 0 1 OPC 3 8 DDE 4 16 EXE 7 128 PON 143 ESE Event Status Enable Register Query Input KESE term Returned lt bit weighting gt term Format nnn Refer to Paragraph 6 1 3 2 for a list of event flags ESR Standard Event Status Register Query Input ESR term Returned lt bit weighting gt Format nnn Remarks The integer returned represents the sum of the bit weighting of the event flag bits in the Standard Event Status Register Refer to Paragraph 6 1 3 2 for a list of event fla
87. 28 110 5 118 2 69954 339 5 165 38 3767 1199 5 25 6 40435 23 72 5 13359 113 5 119 3 75883 365 166 38 9915 1215 26 6 39841 24 2 73 5 06651 116 5 120 4 29687 378 167 39 6038 1230 5 27 6 39214 25 4 74 4 99801 119 5 121 4 74986 389 168 40 2136 1246 28 6 38554 26 6 75 4 92813 122 5 122 5 17977 399 5 169 40 821 1261 5 29 6 37863 27 8 76 4 85687 125 5 123 5 60705 410 170 41 4063 1276 5 30 6 37077 29 1 77 4 78426 128 5 124 6 03172 420 5 171 41 9893 1291 5 31 6 36253 30 4 78 4 71031 131 5 125 6 49428 432 172 42 5699 1306 5 32 6 35391 31 7 79 4 63503 134 5 126 7 09465 447 173 43 1288 1321 33 6 34422 33 1 80 4 55845 137 5 127 8 15226 473 5 174 43 6853 1335 5 34 6 33408 34 5 81 4 48056 140 5 128 8 75291 488 5 175 44 2394 1350 35 6 3235 35 9 82 4 38814 144 129 9 25576 501 176 44 7721 1364 36 6 3117 37 4 83 4 29393 147 5 130 9 74087 513 177 45 3024 1378 37 6 29939 38 9 84 4 19806 151 131 10 2285 525 178 45 8114 1391 5 38 6 2866 40 4 85 4 10051 154 5 132 10 7186 537 179 46 3182 1405 39 6 27241 42 86 4 00133 158 133 11 2317 549 5 180 46 8038 1418 40 6 25768 43 6 87 3 90053 161 5 134 11 7883 563 181 47 2873 1431 41 6 24239 45 2 88 3 79815 165 135 12 3888 577 5 182 47 7684 1444 42 6 22656 46 8 89 3 6942 168 5 136 13 054 593 5 183 48 2287 1456 5 43 6 21019 48 4 90 3 58873 172 137 13 7844 611 184 48 6868 1469 44 6 19115 50 2 91 3 46638 176 138 14 5592 629 5 185 49 1426 1481 5 45 6 17142 52 92 3 34204 180 139 15 378
88. 3 6 45688 4 2 50 6 05645 61 5 97 2 6762 200 5 144 20 8082 777 4 6 45632 4 78 51 6 02997 63 5 98 2 52392 205 145 23 1752 832 5 5 6 45565 5 4 52 6 00271 65 5 99 2 36961 209 5 146 24 5166 864 6 6 45494 6 53 5 97469 67 5 100 2 21329 214 147 25 6001 889 5 7 6 4541 6 65 54 5 94591 69 5 101 2 05503 218 5 148 26 5536 912 8 6 4531 7 35 55 5 91637 71 5 102 1 87703 223 5 149 27 4199 932 5 9 6 45201 8 05 56 5 8861 73 5 103 1 69672 228 5 150 28 2413 952 10 6 45073 8 8 57 5 85508 75 5 104 1 51427 233 5 151 29 0181 970 5 11 6 44934 9 55 58 5 82334 77 5 105 1 32972 238 5 152 29 7714 988 5 12 6 44774 10 35 59 5 78268 80 106 1 12444 244 153 30 5011 1006 13 6 44601 11 15 60 5 74084 82 5 107 0 91675 249 5 154 31 2074 1023 14 6 44403 12 61 5 69792 85 108 0 70686 255 155 31 8905 1039 5 15 6 44189 12 85 62 5 6539 87 5 109 0 47553 261 156 32 571 1056 16 6 43947 13 75 63 5 60879 90 110 0 22228 267 5 157 33 2489 1072 5 17 6 43672 14 7 64 5 5626 92 5 111 0 053112 274 5 158 33 9038 1088 5 18 6 43378 15 65 65 5 51535 95 112 0 350783 282 159 34 5561 1104 5 19 6 43065 16 6 66 5 46705 97 5 113 0 651006 289 5 160 35 2059 1120 5 20 6 42714 17 6 67 5 4177 100 114 0 973714 297 5 161 35 8532 1136 5 21 6 42321 18 65 68 5 36731 102 5 115 1 31919 306 162 36 4979 1152 5 22 6 41905 19 7 69 5 3159 105 116 1 70801 315 5 163 37 14 1168 5 23 6 41442 20 8 70 5 26348 107 5 117 2 14052 326 164 37 7596 1184 24 6 40952 21 9 71 5 199
89. 3 7 2 3 7 3 Lake Shore Model 331 Temperature Controller User s Manual HEATER OUTPUT SETUP The following paragraphs cover the heater wiring from the vacuum shroud to the instrument for both control loop outputs Specifications are detailed in Paragraph 1 3 For help on choosing and installing an appropriate resistive heater refer to Paragraph 2 4 Loop 1 Output Of the two Model 331 control loops Loop 1 is considered the primary loop because it is capable of driving 50 W of heater power The heater output for Loop 1 is a traditional control output for a cryogenic temperature controller It is a variable DC current source with software settable ranges and limits The maximum heater output current is 1 A and maximum compliance voltage is 50 V Heater power is applied in one of three ranges Low Medium or High as specified below Loop 1 Full Scale Heater Power at Typical Resistance Heater Resistance Heater Range Heater Power Low 100 mW 100 Med 1W High 10 W Low 250 mW 250 Med 2 5 W High 25 W Low 500 mW 50 Q Med 5 W High 50 W Loop 1 Heater Output Connector A dual banana jack on the rear panel of the instrument is used for connecting wires to the Loop 1 heater A standard dual banana plug mating connector is included in the connector kit shipped with the instrument This is a common jack and additional mating connectors can be purchased from local electronic suppliers or from Lake Shore P N 106 009
90. 31 to warm up for at least 1 hour with shorts placed across all thermocouple sensor inputs If calibrating a dual thermocouple Model 331 leave a short across the input not currently being calibrated If the other input is diode resistor place a 100 kQ resistor on the input CAUTION All thermocouple connections must be tight and direct with no unnecessary jumpers or connections Thermocouple Input Ranges Calibration Purpose To determine the input offset and gain errors when the input is configured for the thermocouple ranges and provide offset and gain calibration constants back to the Model 331 Process 1 Configure the input for the thermocouple range to be calibrated Turn Room Cal off 2 Reset the calibration constants to their default values using the CALRSTZ and CALRSTG commands EXAMPLE Input A Range Thermo 25mV Zero Offset Reset Command CALRSTZ A 6 Gain Reset Command CALRSTG A 6 Short the V and V terminals together do not tie the terminals to ground 4 Via the interface obtain the input reading using the CALREAD command and record this number 5 Program the offset calibration by negating the value read in the previous step and providing it using the CALZ command EXAMPLE Input A Range Thermo 25mV CALREAD Reading 00 0122 Calibration Command CALZ A 6 0 0122 Ke 8 14 Service Lake Shore Model 331 Temperature Controller User s Manual Thermocouple Input Ranges Calibr
91. 331 Temperature Controller User s Manual National Instruments Primary GPIB Address Secondary GPIB Address Timeout setting Terminate Read on EOS Set EOI with EOS on Writes Type of compare on EOS Send EOI at end of Write System Controller Assert REN when SC Enable Auto Serial Polling Enable CIC Protocol 500nsec Parallel Poll Duration Default Use this GPIB board Board Type Base I O Address GPIBO Configuration GPIB PC2 2A Ver 2 1 Select the primary GPIB address by using the left and right arrow keys This address is used to compute the talk and listen addresses which identify the board or device on the GPIB Valid primary addresses range from O to 30 00H to 1EH Adding 32 to the primary address forms the Listen Address LA Adding 64 to the primary address forms the Talk Address TA EXAMPLE Selecting a primary address of 10 yields the following 10 32 42 10 64 74 Listen address Talk address Fl Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board National Instruments Primary GPIB Address Secondary GPIB Address Timeout setting Serial Poll Timeout Terminate Read on EOS Set EOI with EOS on Writes Type of compare on EOS Send EOI at end of Write Enable Repeat Addressing Fl Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board DEV12 Configuration GPIB PC2 2A Ver 2 1 Select the primary GPIB address by
92. 35 K and room temperature 305 K Accuracy for the PT 102 PT 103 or PT 111 platinum sensor is as follows 250 mK from 70 K to 325 K 500 mK from 325 K to 1400 mK at 480 K DIN Class A or Class B tolerance Three point SoftCal calibrations are performed at liquid nitrogen 77 35 K room temperature 305 K and high temperature 480 K Accuracy for the PT 102 PT 103 or PT 111 platinum sensor is 250 mK from 70 K to 325 K and 250 mK from 325 K to 480 K Advanced Operation 5 9 Lake Shore Model 331 Temperature Controller User s Manual 5 3 5 SoftCal Calibration Curve Creation Once the calibration data points have been obtained you may create a SoftCal calibration This example illustrates SoftCal of a DT 470 Diode Press the Curve Entry key Press the A or Y key until you see the following display hr dr Press the Enter key You can press the Escape key anytime during this routine to return to the normal display Use the A or Y key to cycle through the sensor type you wish to SoftCal DT 470 PT 100 and PT 1000 Once the sensor type is selected press the Enter key You will see the following message NOTE The copy routine allows you to overwrite an existing user curve Please ensure the curve number you are writing to is correct before proceeding with curve copy Use the A or Y key to select the user curve location where the SoftCal curve will be stored You can choose
93. 3500 21 4 55 3 09485 6 60 90 3 44351 0 765 21 3 03615 20 6 56 3 09791 6 35 91 3 47148 0 690 22 3 03716 19 95 57 3 10191 6 05 92 3 50420 0 615 23 3 03797 19 45 58 3 10638 5 74 93 3 54057 0 545 24 3 03882 18 95 59 3 11078 5 46 94 3 58493 0 474 25 3 03971 18 45 60 3 11558 5 18 95 3 63222 0 412 26 3 04065 17 95 61 3 12085 4 90 96 3 68615 0 354 27 3 04164 17 45 62 3 12622 4 64 97 3 75456 0 295 28 3 04258 17 00 63 3 13211 4 38 98 3 82865 0 245 29 3 04357 16 55 64 3 13861 4 12 99 3 91348 0 201 30 3 04460 16 10 65 3 14411 3 92 100 4 01514 0 162 31 3 04569 15 65 66 3 14913 3 75 101 4 14432 0 127 32 3 04685 15 20 67 3 15454 3 58 102 4 34126 0 091 33 3 04807 14 75 68 3 16002 3 42 103 4 54568 0 066 34 3 04936 14 30 69 3 16593 3 26 104 4 79803 0 050 35 3 05058 13 90 70 3 17191 3 11 D 4 Curve Tables Lake Shore Model 331 Temperature Controller User s Manual Table D 6 Lake Shore RX 202A Rox Curve pomt mp ag pont 092 le pame ml e 1 3 35085 40 0 34 3 40482 11 45 67 3 52772 2 17 2 3 35222 38 5 35 3 40688 11 00 68 3 53459 2 04 3 3 35346 37 2 36 3 40905 10 55 69 3 54157 1 92 4 3 35476 35 9 37 3 41134 10 10 70 3 54923 1 80 5 3 35612 34 6 38 3 41377 9 65 71 3 55775 1 68 6 3 35755 33 3 39 3 41606 9 25 72 3 56646 1 57 7 3 35894 32 1 40 3 41848 8 85 73 3 57616 1 46 8 3 36039 30 9 41 3 42105 8 45 74 3 58708 1 35 9 3 36192 29 7 42 3 42380 8 05 75 3 59830 1 25 10 3 36340 28 6 43 3 42637
94. 550 138 50 74 2 324710 378 50 7 5 214770 7 90 41 2 776950 143 50 75 2 523070 387 50 8 5 196980 9 05 42 2 675700 148 50 76 2 643480 393 00 9 5 176250 10 35 43 2 563610 154 00 17 2 708890 396 00 10 5 150910 11 90 44 2 450770 159 50 78 2 764030 398 50 11 5 116700 13 95 45 2 337230 165 00 79 2 797580 400 00 12 5 049770 17 90 46 2 223010 170 50 80 2 950200 406 50 13 5 002120 20 70 47 2 097700 176 50 81 3 008310 409 00 14 4 938000 24 50 48 1 971630 182 50 82 3 031200 410 00 15 4 876180 28 20 49 1 844890 188 50 83 3 218040 418 00 16 4 801670 32 70 50 1 706840 195 00 84 3 300110 421 50 17 4 648620 42 00 51 1 568040 201 50 85 4 000810 451 50 18 4 569170 46 80 52 1 428520 208 00 86 4 246390 462 00 19 4 499080 51 00 53 1 277520 215 00 87 4 701810 481 50 20 4 435090 54 80 54 1 114900 222 50 88 4 947390 492 00 21 4 370520 58 60 55 0 940599 230 50 89 5 636410 521 50 22 4 303610 62 50 56 0 754604 239 00 90 5 870300 531 50 23 4 234290 66 50 57 0 556906 248 00 91 6 547630 560 50 24 4 164270 70 50 58 0 358437 257 00 92 6 711600 567 50 25 4 093560 74 50 59 0 170179 265 50 93 6 781410 570 50 26 4 022170 78 50 60 0 041150 275 00 94 6 931500 577 00 27 3 950100 82 50 61 0 152699 280 00 95 7 001360 580 00 28 3 877360 86 50 62 0 163149 280 50 96 7 166710 587 00 29 3 803960 90 50 63 0 374937 290 00 97 7 260420 591 00 30 3 729910 94 50 64 0 542973 297 50 98 7 412010 597 50 31 3 655230 98 50 65 0 598604 300 00 99 7 529070 602 50 32 3
95. 6 649 186 49 5779 1493 5 46 6 15103 53 8 93 3 21584 184 140 16 2428 669 5 187 50 0111 1505 5 47 6 12998 55 6 94 3 08778 188 141 17 1518 691 D 6 Curve Tables Lake Shore Model 331 Temperature Controller User s Manual Table D 8 Type E Nickel Chromium vs Copper Nickel Thermocouple Curve gier mV Temp K geg mV Temp K e mV Temp K 1 9 834960 3 15 55 8 713010 77 50 109 0 701295 285 00 2 9 834220 3 59 56 8 646710 80 00 110 1 061410 291 00 3 9 833370 4 04 57 8 578890 82 50 111 1 424820 297 00 4 9 832260 4 56 58 8 509590 85 00 112 1 791560 303 00 5 9 830920 5 12 59 8 438800 87 50 113 2 161610 309 00 6 9 829330 5 72 60 8 366570 90 00 114 2 534960 315 00 7 9 827470 6 35 61 8 292900 92 50 115 2 943070 321 50 8 9 825370 7 00 62 8 217810 95 00 116 3 355100 328 00 9 9 822890 7 70 63 8 141330 97 50 117 3 770870 334 50 10 9 820010 8 45 64 8 047780 100 50 118 4 190420 341 00 11 9 816880 9 20 65 7 952190 103 50 119 4 613650 347 50 12 9 813290 10 00 66 7 854690 106 50 120 5 040520 354 00 13 9 809180 10 85 67 7 755260 109 50 121 5 470960 360 50 14 9 804510 11 75 68 7 653960 112 50 122 5 938380 367 50 15 9 799510 12 65 69 7 550790 115 50 123 6 409870 374 50 16 9 793900 13 60 70 7 445790 118 50 124 6 885210 381 50 17 9 787610 14 60 71 7 338970 121 50 125 7 364360 388 50 18 9 780590 15 65 72 7 230370 124 50 126 7 881760 3
96. 7031 Varnish formerly GE 7031 Varnish 1 pint can IMI 7031 Insulating Varnish and Adhesive possesses electrical and bonding properties which when combined with its chemical resistance and good saturating properties make it an excellent material for VGE 7031 cryogenic temperatures As an adhesive IMI 7031 bonds a variety of materials has fast tack time and may be air dried or baked It is also an electrically insulating adhesive at cryogenic temperatures and is often used as a calorimeter cement When soaked into cigarette paper it makes a good high thermal conductivity low electrical conductivity heat sinking layer Maximum operating temperature 423 K 150 C Lake Shore Cryogenic Wire Lake Shore sells the following types of cryogenic wire DT Duo Twist MN Single Strand MW Manganin NC Nichrome Heater ND Heavy Duty QL Quad Lead and QT Quad Twist Lake Shore Coaxial Cable Lake Shore sells the following types of coaxial cable CC Ultra Miniature Coaxial Cable SR Semi Rigid Coaxial Cable CRYC CryoCable Accessories included with a new Model 331 Options and Accessories 7 3 Lake Shore Model 331 Temperature Controller User s Manual CONNECTOR PLUG QTY 2 YA BLK_ lt GRN gt REAR VIEW DOUBLE BANANA PLUG SINGLE BANANA PLUG P 331 7 1 bmp Figure 7 1 Model 3507 2SH Cable Assembly 7 4 MODEL 3003 HEATER OUTPUT CONDITIONER The Lake Shore Model 3003 Heater Output Cond
97. 80 5 4 4 58043 9 75 35 1 66004 191 5 4 53965 12 5 36 1 47556 200 5 6 4 47226 16 95 37 1 0904 220 7 4 43743 19 3 38 0 73397 237 5 8 4 39529 22 2 39 0 68333 240 9 4 34147 26 40 0 3517 256 10 4 29859 29 1 41 0 2385 261 5 11 4 26887 31 3 42 0 078749 277 12 4 22608 34 5 43 0 139668 280 13 4 2018 36 3 44 0 426646 294 5 14 4 02151 49 8 45 0 546628 300 5 15 3 94549 55 4 46 0 858608 316 16 3 87498 60 5 47 0 938667 320 17 3 80464 65 5 48 1 3456 340 18 3 73301 70 5 49 1 7279 358 5 19 3 65274 76 50 1 76905 360 5 20 3 5937 80 51 2 20705 381 5 21 3 51113 85 5 52 2 51124 396 22 3 45023 89 5 53 2 69878 405 23 3 43451 90 5 54 2 94808 417 24 3 37842 94 55 3 13562 426 25 3 35469 95 5 56 3 43707 440 5 26 3 28237 100 57 3 85513 460 5 27 3 11919 110 58 4 17136 475 5 28 2 95269 120 59 4 28662 481 29 2 78168 130 60 4 64037 498 30 2 60639 140 61 4 68168 500 31 2 42737 150 This thermocouple is no longer sold by Lake Shore Curve Tables D 9 Lake Shore Model 331 Temperature Controller User s Manual Table D 11 Chromel AuFe0 07 Thermocouple Curve S ch ee A e Les 1 5 279520 3 15 35 3 340820 115 00 69 1 313400 332 50 2 5 272030 3 78 36 3 253410 119 50 70 1 511140 341 50 3 5 263500 4 46 37 3 165360 124 00 71 1 709250 350 50 4 5 253730 5 20 38 3 076690 128 50 72 1 928940 360 50 5 5 242690 6 00 39 2 977480 133 50 73 2 127070 369 50 6 5 229730 6 90 40 2 877
98. 96 00 19 9 773150 16 70 73 7 120010 127 50 127 8 403380 403 50 20 9 764910 17 80 74 6 989110 131 00 128 8 928940 411 00 21 9 755820 18 95 75 6 855790 134 50 129 9 493760 419 00 22 9 746230 20 10 76 6 720200 138 00 130 10 0629 427 00 23 9 735700 21 30 77 6 582330 141 50 131 10 6361 435 00 24 9 724650 22 50 78 6 442220 145 00 132 11 2494 443 50 25 9 713080 23 70 79 6 299900 148 50 133 11 867 452 00 26 9 699960 25 00 80 6 155400 152 00 134 12 5253 461 00 27 9 686220 26 30 81 6 008740 155 50 135 13 188 470 00 28 9 671890 27 60 82 5 859960 159 00 136 13 892 479 50 29 9 655790 29 00 83 5 687430 163 00 137 14 6005 489 00 30 9 638980 30 40 84 5 512090 167 00 138 15 3507 499 00 31 9 621500 31 80 85 5 334130 171 00 139 16 1432 509 50 32 9 602020 33 30 86 5 153520 175 00 140 16 9403 520 00 33 9 581740 34 80 87 4 970330 179 00 141 17 7798 531 00 34 9 560710 36 30 88 4 784590 183 00 142 18 6624 542 50 35 9 537440 37 90 89 4 596330 187 00 143 19 5881 554 50 36 9 513290 39 50 90 4 405600 191 00 144 20 5573 567 00 37 9 486720 41 20 91 4 212440 195 00 145 21 5702 580 00 38 9 457560 43 00 92 3 992330 199 50 146 22 627 593 50 39 9 427340 44 80 93 3 769140 204 00 147 23 7279 607 50 40 9 396080 46 60 94 3 543070 208 50 148 24 873 622 00 41 9 363810 48 40 95 3 314120 213 00 149 26 0623 637 00 42 9 330540 50 20 96 3 082340 217 50 150 27 3356 653 00 43 9 296270 52 00 97 2 847790
99. E with the sum of the bit weighting for each desired bit Refer to Paragraph 6 1 3 1 for a list of status flags To enable status flags 0 2 4 and 6 send the command SRE 89 term 89 is the sum of the bit weighting for each bit Bit Bit Weighting Event Name 1 0 New A amp B 3 8 Alarm 4 16 Error 6 64 SRQ 89 Service Request Enable Register Query SRE term lt bit weighting gt term nnn Refer to Paragraph 6 1 3 1 for a list of status flags Status Byte Query STB term lt bit weighting gt term nnn Acts like a serial poll but does not reset the register to all zeros The integer returned represents the sum of the bit weighting of the status flag bits that are set in the Status Byte Register Refer to Paragraph 6 1 3 1 for a list of status flags Remote Operation 6 25 TST Input Returned Format Remarks WAI Input Remarks ALARM Input Format Remarks Example ALARM Input Format Returned Format Lake Shore Model 331 Temperature Controller User s Manual Self Test Query TST term lt status gt term n lt status gt 0 no errors found 1 errors found The Model 331 reports status based on test done at power up Wait to Continue Command KWAI term This command is not supported in the Model 331 Input Alarm Parameter Command ALARM lt input gt lt off on gt lt source gt lt high value gt lt low value gt lt deadband gt lt latch enab
100. EE 4 26 4 14 3 RTE 4 27 4 15 ALARMS AND RELAYS iii a ade 4 28 4 15 1 LE EE 4 28 4 15 2 O E E ied gcctetentie Gaeta See ae Sead E E TE 4 30 4 16 ANALOG QUTPU Ti A add 4 31 4 16 1 Analog Output In Input Mode ioioccocconococincccicnican baaaie edi 4 31 4 16 2 Analog Output In Manual Mode ooooococcnccccnonoccnonononcnononononono cnn nnnnno cnn rn n nn nano rn rr narran rn rre rra 4 33 4 16 3 Analog Output In Loop 2 Mode 4 34 4 17 LOCKING AND UNLOCKING THE KEYPAD coooccccoccccccconcccnononcnonononcnnnnnnnnc nano ncn nro nnn nan nnn naar nnnr ninas 4 34 4 18 DISPLAY BRIGHTNESS ci ais 4 35 4 19 REMOTE LOCA D as a e Aaaa Aa Na E EEE RAET R iuit 4 35 4 20 INTERFACE ocio aid 4 35 4 21 DEFAULT VALUES oia A o ao 4 37 5 ADVANCED OPERATION onnciccccconscccinnsirnnncrns rr 5 1 5 0 GENERAL 000 a ltda 5 1 5 1 CURVE NUMBERS AND STORAGE ccccccococccccoconcnononcncnnnonnnnnnnn cnn nnnnn nn nano nr rr narrar r nr nn rre narran 5 1 5 1 1 Curve Header Parameters A 5 1 5 1 2 Curve BreakpointS ciar ios 5 2 5 2 FRONT PANEL CURVE ENTRY OPERATIONS AA 5 2 5 2 1 lee 5 4 5 2 1 1 Thermocouple Curve Considerations nn nn nn nn rn nana rca rn cnn rr 5 5 5 2 2 Erase Curve 5 2 3 Copy Curve 5 3 SOFT EE 5 3 1 SoftCal With Silicon Diode Sensors oooooconccccnnococccnononnnononononononcncnnnn cnn rn non cnn nan nn nn naar rca ran n rra nan nnnnnnns 5 7 5 3 2 SoftCal Accuracy With Silicon Diode Gensors nn nc nano nnnn naar nnn nan nnnnnnns 5 8 5 3 3 SoftCal With
101. ES Type exit to end program Command Response 15 Type in a command or query in the Command box as described in Paragraph 6 1 4 5 16 Press Enter or select the Send button with the mouse to send command 17 Type Exit and press Enter to quit 6 8 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Table 6 2 Visual Basic IEEE 488 Interface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Click gSend True End Sub Routine to handle Send button press Set Flag to True Private Sub Form Load Dim strReturn As String Dim term As String Dim strCommand As String Dim intDevice As Integer frmIEEE Show term Chr 13 Chr 10 strReturn Call ibdev 0 12 0 T10s 1 amp H140A intDevice Main code section Used to return response Terminators Data string sent to instrument Device number used with IEEE Show main window Terminators are lt CR gt lt LF gt Clear return string Initialize the IEEE device Do Do Wait loop DoEvents Give up processor to other events Loop Until gSend True Loop until Send button pressed gSend False Set Flag as False strCommand frmIEEE txtCommand Text Get Command strReturn Clear response display strCommand UCase strCommand Set all characters to upper case If strCommand EXIT Then Get out on EXIT End End If Call ibwrt intDevice strCommand amp te
102. Equation Data Query 33 STB Status Byte Query sece 25 LINEAR Input Linear Equation Cmd 33 TST Self Test Query cene 26 LINEAR Input Linear Equation Query 34 WAI Wait To Continue Cmd c oococcccconocnccccnnns 26 LOCK Front Panel Keyboard Lock Cmd 34 ALARM Input Alarm Parameter Cmd coco 26 LOCK Front Panel Keyboard Lock Query 34 ALARM Input Alarm Parameter Query 26 MDAT Min Max Data Query 34 ALARMST Input Alarm Status Query ee 26 MNMX Min Max Input Function Cmd 34 ALMRST Reset Alarm Status Cmd ee 27 MNMX Min Max Input Function Query 35 ANALOG Analog Output Parameter Cmd 27 MNMXRST Min Max Function Reset Cmd 35 ANALOG Analog Outputs Parameter Query 27 MODE Set Local Remote Mode ce 35 AOUT Analog Output Data Ouenm 27 MODE Query Local Remote Mode 35 BEEP System Beeper Cmd cece 27 MOUT Control Loop MHP Output Cmd 35 BEEP System Beeper Ouer 27 MOUT Control Loop MHP Output Query 35 BRIGT Display Brightness Command 28 PID Control Loop PID Values Cmd 36 BRIGT Display Brightness Query ee 28 PID Control Loop PID Values Query 36 CMODE Control Loop Mode Cmd 28 RAMP Control Loop Ramp Cmd 36 CMODE Control Loop Mode Ouer 28 RAMP Control Loop Ramp Ouer 36 CRDG Cel
103. If it is set improperly check the first two breakpoints A positive coefficient indicates the sensor signal increases with increasing temperature A negative coefficient indicates the sensor signal decreases with increasing temperature Table 5 2 Recommended Curve Parameters Typical Lake e Limit Es Recommended Type Shore Model Units Format K Coeficient Sensor Resolution Silicon Diode DT 470 Volts VIK 475 Negative 0 00001 V GaAlAs Diode TG 120 Volts VIK 325 Negative 0 00001 V Platinum 100 PT 100 Ohms Q K 800 Positive 0 001 Q Platinum 1000 PT 100 Ohms Q K 800 Positive 0 01 Q Rhodium lron RF 100 Ohms Q K 325 Positive 0 001 Q Carbon Glass CGR 1 1000 Ohms logQ K 325 Negative 0 00001 logQ CX 1030 Ohms logQ K 325 Negative 0 00001 log Cernox Germanium GR 200A 100 Ohms logQ K 325 Negative 0 00001 logQ Rox RX 102A Ohms logQ K 40 Negative 0 00001 log Type K 9006 005 mV mV K 1500 Positive 0 0001 mV Type E 9006 003 mV mV K 930 Positive 0 0001 mV Type T 9006 007 mV mV K 673 Positive 0 0001 mV Au Fe 0 03 No Longer Sold mV mV K 500 Positive 0 0001 mV Au Fe 0 07 9006 001 mV mV K 610 Positive 0 0001 mV Advanced Operation 5 3 Lake Shore Model 331 Temperature Controller User s Manual 5 2 1 Edit Curve The Edit Curve
104. K 50 mK 300K 25mK 50 mK 340K 100 mK 480K 100 mK A curve is fitted to these points A detailed report including Raw Temperature Data Polynomial Fits and Interpolation Tables comes with the sensor Precision ape Option User calculates break points and manually enters data into the controller 8001 331 Factory installs a NOVRAM with Precision Option breakpoint pairs loaded in it 8000 Users download Precision Option breakpoint pairs in ACSII format from a floppy disk 8002 05 331 Users install a NOVRAM with Precision Option breakpoint pairs loaded in it C 331 2 1 eps Figure 2 1 Silicon Diode Sensor Calibrations and CalCurve 2 4 Cooling System Design 2 3 Lake Shore Model 331 Temperature Controller User s Manual SENSOR INSTALLATION This section highlights some of the important elements of proper sensor installation For more detailed information Lake Shore sensors are shipped with installation instructions that cover that specific sensor type and package The Lake Shore Temperature Measurement and Control Catalog includes an installation section as well To further help users properly install sensors Lake Shore offers a line of Cryogenic Accessories Many of the materials discussed are available through Lake Shore and can be ordered with sensors or instruments Mounting Materials Choosing appropriate mounting materials is very important in a cryogenic environment The
105. K the sensitivity of a silicon diode is lower so the error would be close to 50 mK Again this may not be a problem for every user Lowering Measurement Noise Good instrument hardware setup technique is one of the least expensive ways to reduce measurement noise The suggestions fall into two categories 1 Do not let noise from the outside enter into the measurement and 2 Let the instrument isolation and other hardware features work to their best advantage Here are some further suggestions Use four lead measurement whenever possible Do not connect sensor leads to chassis or earth ground If sensor leads must be grounded ground leads on only one sensor Use twisted shielded cable outside the cooling system Attach the shield pin on the sensor connector to the cable shield Do not attach the cable shield at the other end of the cable not even to ground Run different inputs and outputs in their own shielded cable Use twisted wire inside the cooling system Use similar technique for heater leads Use a grounded receptacle for the instrument power cord Consider ground strapping the instrument chassis to other instruments or computers D D D D D D D 3 6 Installation Lake Shore Model 331 Temperature Controller User s Manual 3 6 THERMOCOUPLE SENSOR INPUTS Model 331X TX Only 3 6 1 3 6 2 3 6 3 The information in this paragraph is for a Model 331 configured at the factory with one or two the
106. LE OF CONTENTS Continued Chapter Paragraph Title Page Sc HINSTALLATION A O EAT 3 1 3 0 GENERAL ai EEN 3 1 3 1 INSPECTION AND UNPACKING A 3 1 3 2 REPACKAGING FOR SHIPMENT A 3 1 3 3 REAR PANEL DEFINITION ui td 3 2 3 4 LINE INPUT ASSEMBLY cuicos lar 3 3 3 4 1 Eine VONAGE EE 3 3 3 4 2 Line Fuse and Fuse Older co e ENEE 3 3 3 4 3 A dert g e gateecacueneesvbeateeauatstepeceacbesteodenusydesebest A ai iaeei ipai der ESu 3 3 3 4 4 ere EE 3 4 3 5 DIODE RESISTOR SENSOR INPDUTE nn nn nano nn nr n nan nnn nan nn nr nnnn nn ncnnnnss 3 4 3 5 1 Sensor Input Connector and Pinout nn no nar nnc nano rr rr rra 3 4 3 5 2 Sensor Lead Cable EE 3 5 3 5 3 Grounding and Shielding Sensor Leads oooooccccnoncccnnococcnononcnnnonncnn non nnn nano nn rro rr rn 3 5 3 5 4 Sensor Polarity EE 3 5 3 5 5 Four Lead Sensor Measurement cee ceeeeeeceeeneeeeeenneeeceeeeaeeeceneeeeesaaeeeseeaaeeeseneaeeessnaeeeenenaeeeenaeees 3 6 3 5 6 Two Lead Sensor Measurement concilio a aa a eii 3 6 3 5 7 Lowering Measurement Noise cnrirnisiinip dao 3 6 3 6 THERMOCOUPLE SENSOR INPUTS odccccccccoccnococononononcncnononcnononnncnnnonnncnonn cnn nnnnn cnn naar are rnnnn nn nnnnnncnnnns 3 7 3 6 1 Sensor Input erminalS viciosa Eder 3 7 3 6 2 Thermocouple InstallatiON oommicin ni aos 3 7 3 6 3 Grounding aNd Shieldidg EE 3 7 3 7 HEATER OUTPUTSE TU Picnic ind 3 8 3 7 1 Ree ele 3 8 3 7 2 Loop 1 Heater Output ConnectoF cciiriomimsiaiara ida dc 3 8 3 7 3 Loop 1 Heater
107. Mode Off and the output will always be a positive voltage Operation 4 33 Lake Shore Model 331 Temperature Controller User s Manual 4 16 3 Analog Output In Loop 2 Mode In Loop 2 mode the analog output is directly controlled by Model 331 To place the analog output in Loop 2 mode press the Analog Output key then press the A or Y key until you see the following display ns HA y Ps DL TF ar Press the A or Y key to toggle between Bipolar Mode Of or Off Bipolar Mode On allows the control output to go negative This is only needed when controlling a thermoelectric device For most cases Bipolar Mode should be Off Press the Enter key The instrument returns to the normal display 4 17 LOCKING AND UNLOCKING THE KEYPAD The keypad lock feature prevents accidental changes to parameter values When the keypad is locked some parameter values may be viewed but most cannot be changed from the front panel Alarm Reset and Heater Off are the only keypad functions that remain active when the keypad is locked A 3 digit keypad lock code locks and unlocks the keypad The factory default code is 123 The code can be changed only through the computer interface If instrument parameters are reset to default values the lock code resets also The instrument cannot reset from the front panel with the keypad locked To lock the keypad press and hold the Enter key for 10 seconds to display the screen shown as follows
108. Platinum Sensors ooccnnnnccconococcnononnncnnnonnnnnnnncnnnn non nncnnnnn nn rn n nn anar rn rr naar rra ran n na annann nne 5 9 5 3 4 SoftCal Accuracy With Platinum Gensors nono nnn nan nn nr nana nn nr nen nnnnn nan nnninns 5 9 5 3 5 SoftCal Calibration Curve Creton 5 10 6 COMPUTER INTERFACE OPERATION ccccccsseeeesessereeeeeeeeeeseceeeeeseenseseeeeesesseeeeseseaeseseseeesesseeeeseseenseseeensnssoneeenss 6 1 6 0 GENERAL uote dad edits sees 6 1 6 1 IEEE 488 INTERFACE occ ataca 6 1 6 1 1 IEEE 488 Interface Parameters icini incearca ie 6 2 6 1 2 IEEE 488 Command Structure scsi idiotas 6 2 6 1 3 Status Regist iia ro 6 4 6 1 4 IEEE Interface Example Programs ooocococooccccconoccnonononononononcnnnoncnnnnnn cnn rra nn EAEE EEEN AEAEE EEEE EEEn Enne neant 6 5 6 1 5 Troubleshooting escitas 6 13 Table of Contents iii Lake Shore Model 331 Temperature Controller User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 6 2 SERIAL INTERFACE OVERVIEW iitcoviciar e a dc 6 14 6 2 1 Physical Connector eener ee EAR EENS ES ee 6 14 6 2 2 Hardware EE 6 14 6 2 3 Character Fomati ssie inesi t 6 15 6 2 4 Message nl citada 6 15 6 2 5 Message Flow Control osese a ci 6 16 6 2 6 Changing Baud Rate icono A a add 6 16 6 2 7 Serial Interface Example Programs cccccceeeesseeeeeeeeeeeeneeeeeeeaeeeeeeeeeeeesaeeeeeeaeeeseneeeeeeneeeeseaaes 6 17 6 2 8 TroubleshootiINO cio anta cercada 6 21 6 3 COMMAND SUMMARY 00 eeeccceeec
109. The cursor will jump to the temperature reading Again use numerical keypad to enter the temperature the measurement was taken at For this example we will enter 77 K Press the Enter key NOTE If Point 3 is not being used press the Enter key with both settings at their default value to complete the SoftCal calibration Use the numerical keypad to enter the measured data point at or near room temperature 305 K Temperatures outside the range of 200 350 K are not permitted For this example we will enter 0 51583 Press the Enter key The cursor will jump to the temperature reading Again use numerical keypad to enter the temperature the measurement was taken at For this example we will enter 302 5 K Press the Enter key The new curve is automatically generated and you will return to the normal display You can check the new curve using the Edit Curve instructions in Paragraph 5 2 1 The curve is not automatically assigned to either input so the new curve must be assigned to an input by the user Advanced Operation 5 11 Lake Shore Model 331 Temperature Controller User s Manual This Page Intentionally Left Blank 5 12 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual 6 0 6 1 CHAPTER 6 COMPUTER INTERFACE OPERATION GENERAL This chapter provides operational instructions for the computer interface for the Lake Shore Model 331 Temperature Controller Either of the two comp
110. User s Manual Model 331 Temperature Controller LakeShore 331 Temperature Controller Control A Tune Remote IODODDTDOODDDDDIDO o HOUOL RUDI HOUOL E SS Control Zone Input Display Alarm remo Heater Setup Setting Setup Format Range pa E 7 807 PID Curve Analog Setpoint MHP Entry Math Output Interface el OTTO DI CC Gg Includes Coverage For Model 331S and Model 331E LakeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA E mail Addresses sales lakeshore com service lakeshore com Visit Our Website At www lakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Revision 1 6 P N 119 031 16 August 2002 Lake Shore Model 331 T
111. a query does not initiate a response from the instrument A response string is sent by the instrument only when it is addressed as a talker and the computer becomes the listener The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in Paragraph 6 3 Remote Operation 6 3 6 1 3 6 1 3 1 6 1 3 2 Lake Shore Model 331 Temperature Controller User s Manual Status Registers There are two status registers the Status Byte Register described in Paragraph 6 1 3 1 and the Standard Event Status Register in Paragraph 6 1 3 2 Status Byte Register and Service Request Enable Register The Status Byte Register contains six bits of information about the operation of the Model 331 STATUS BYTE REGISTER FORMAT A SAA A RATA AA Weighting ee ee a a Bit Name Ramp Not Not New If Service Request is enabled any of these bits being set will cause the Model 331 to pull the SRQ management line low to signal the BUS CONTROLLER These bits are reset to zero upon a serial poll of the Status Byte Register These reports can be inhibited by turning their corresponding bits in the Service Request Enable Register to off The Service Request Enable Register allows the user to inhibit or enable any of the status reports in the Status Byte Register The SRE command is used to s
112. ake Shore RF family of sensors Rhodium iron is a spin fluctuation alloy which has a significant temperature coefficient of resistance below 20 K where most metals rapidly lose sensitivity Roman numerals Letters employed in the ancient Roman system of numeration as follows l 1 VI 6 L 50 II 2 VII 7 C 100 lll 3 VI 8 D 500 IV 4 IX 9 M 1000 V 5 X 10 root mean square RMS The square root of the time average of the square of a quantity for a periodic quantity the average is taken over one complete cycle Also known as effective value room temperature compensation Thermocouples are a differential measurement device Their signal represents the difference in temperature between their ends An ice bath is often used to reference the measurement end to 0 degrees Celsius so most curves are normalized to that temperature Room temperature compensation replaces an ice bath by monitoring the temperature of the thermocouple terminals and normalizing the reading mathematically RS 232C Bi directional computer serial interface standard defined by the Electronic Industries Association EIA The interface is single ended and non addressable Seebeck effect The development of a voltage due to differences in temperature between two junctions of dissimilar metals in the same circuit self heating Heating of a device due to dissipation of power resulting from the excitation applied to the device The output signal from a sensor increases with excitation le
113. am Control Properties Current Name Property New Value Label1 Name IbIExitProgram Caption Type exit to end program Label2 Name IblCommand Caption Command Label3 Name IblResponse Caption Response Text1 Name txtCommand Text lt blank gt Text2 Name txtResponse Text lt blank gt Command1 Name cmdSend Caption Send Default True Form1 Name frmSerial Caption Serial Interface Program Timer1 Enabled False Interval 10 12 Add code provided in Table 6 6 a Inthe Code Editor window under the Object dropdown list select General Add the statement Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 6 6 c Inthe Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form_Load Add the code to this subroutine as shown in Table 6 6 d Double Click on the Timer control Add code segment under Private Sub Timer1_Timer as shown in Table 6 6 e Make adjustments to code if different Com port settings are being used 13 Save the program 14 Run the program The program should resemble the following ig Serial Interface Program Al ES Type exit to end program Command Response 15 Type in a command or query in the Command box as described in Paragraph 6 2 7 3 16 Pre
114. and less than 100 The load temperature should stabilize at a temperature below the setpoint If the load temperature and heater meter swing rapidly the heater range may be set too high and should be reduced Very slow changes in load temperature that could be described as drifting are an indication of a proportional setting that is too low which is addressed in the next step Gradually increase the proportional setting by doubling it each time At each new setting allow time for the temperature of the load to stabilize As the proportional setting is increased there should be a setting in which the load temperature begins a sustained and predictable oscillation rising and falling in a consistent period of time See Figure 2 3 a The goal is to find the proportional value in which the oscillation begins do not turn the setting so high that temperature and heater output changes become violent Record the proportional setting and the amount of time it takes for the load change from one temperature peak to the next The time is called the oscillation period of the load It helps describe the dominant time constant of the load which is used in setting integral If all has gone well the appropriate proportional setting is one half of the value required for sustained oscillation See Figure 2 3 b 2 12 Cooling System Design Lake Shore Model 331 Temperature Controller User s Manual Tuning Proportional Continued 2 8 If the load do
115. appears Use the A or Y key to turn room temperature compensation on or off then press the Enter key The default setting is On If curve is set to None the room temperature compensation selection is automatically turned off Operation 4 9 4 4 3 2 Lake Shore Model 331 Temperature Controller User s Manual Room Temperature Calibration Procedure Room temperature calibration is used to calibrate the built in compensation and is recommended when a thermocouple is first installed or any time a thermocouple is changed Factory calibration of the instrument is accurate to within approximately 1 K Differences in thermocouple wire and installation technique create errors greater than the instrument errors Therefore the best accuracy is achieved by calibrating with the thermocouple actually being used because it eliminates all sources of error If that is not possible use a thermocouple made from the same wire For less demanding applications a short across the input terminals will suffice If the Model 331 is configured as dual thermocouple unit calibrate both inputs even if they use the same type of thermocouple An appropriate curve must be selected and room temperature compensation must be turned on before calibration can be started There are three options for room temperature calibration Cleared The previous room temperature calibration value is cleared and no adjustment will be made to the temperature value
116. ard Null Modem Cable DE 9S to DE 9S PC DE 9P 5 GND a es GND 2 RD in 1 A TD ont 3 TD out lt gt 2 RD in 4 DTR out 25 6 DSR in 6 DSR in A A DTR out 1 NC 9 7 A RTS out 7 DTR tied to 4 gt 8 CTS in 8 NC 2 eee seer 1 DCD in Model 331 to PC Serial Interface PC with DB 25P Model 331 DE 9P Standard Null Modem Cable DE 9S to DB 25S PC DB 25P GND E EN 2 RD in SS E D 00 3 TD ot gt 3 RD in 1 NC i 4 RTS out 7 DTR tied to 4 L 5 CTS in 8 NC E 8 DCD in 6 DSR in 20 DTR out 4 DTR out 6 DSR in Model 331 to PC Interface using Null Modem Adapter Model 331 DE 9P Null Modem Adapter PC DE 9P 5 GND Te 2 RD in A TD ont 3 TD out gt 2 RD in 1 NC HAYA A BTR out 6 DSR in a ES 1 DCD in 4 DTR out 6 DSR in 7 DTR tied to 4 gt 8 CTS in 8 NC IZ T RTS ou 9 NC O O EA O NOTE Same as null modem cable design except PC CTS is provided from the Model 331 on DTR Service 8 5 Lake Shore Model 331 Temperature Controller User s Manual 8 4 2 IEEE 488 Interface Connector Connect to the IEEE 488 Interface connector on the Model 331 rear with cables specified in the IEEE 488 1978 standard document The cable has 24 conductors with an outer shield The connectors are 24 way Amphenol 57 Series or equivalent with piggyback receptacles to allow daisy chaining in mu
117. atch a published standard curve and sold at a premium but in general these sensors do not provide the accuracy of a calibrated sensor For convenience the Model 331 has several standard curves included in firmware CalCurve The CalCurve service provides the user with a convenient way get the temperature response curve from Lake Shore calibrated sensors into instruments like the Model 331 It can be performed at the factory when calibrated sensors and instruments are ordered together The factory installed CalCurve option is Model 8001 331 and should be ordered with the calibrated sensor A CalCurve can be done in the field when additional or replacement sensors are installed Curve data is loaded into some type of non volatile memory that is installed into the instrument by the user In the case of the Model 331 the curve is loaded into a non volatile memory which can be installed into the instrument The field installed version is a Model 8002 05 331 and should be ordered with the calibrated sensor Customers that have a PC compatible computer with an RS 232C or IEEE 488 interface have another option The Model 8000 is included with the calibrated sensor and can be loaded by the user Cooling System Design 2 3 Lake Shore Model 331 Temperature Controller User s Manual Regarding accuracy there are 3 things that can be done with a temperature sensor Lake Shore Silicon Diode Temperature Sensor Standard Standard sensors are int
118. ation Continued 6 Connect input to standard and DMM with cable described in Paragraph 8 9 1 7 Set the voltage reference to provide the calibration voltage shown in Table 8 3 Using the DMM measure the voltage to the tolerance shown in Table 8 3 8 Via the interface obtain the input reading using the CALREAD command and record this number 9 Program the gain calibration by dividing the measured value of the reference voltage by the value read in the previous step and provide the result using the CALG command Note that the gain calibration constant will always be within 5 of 1 00000 EXAMPLE Input A Range Thermo 25mV Measured Value of Reference Voltage 25 0032 mV DC CALREAD Reading 24 9867 Constant Calculation 25 0032 24 9867 1 00066 Calibration Command CALG A 6 1 00066 10 Send the CALSAVE command to save the constants in the E prom 11 Perform calibration on both thermocouple ranges 12 Repeat for second input if thermocouple Table 8 3 Calibration Table for Thermocouple Ranges Range Voltage Reference Reference Voltage Cal Command Output Known to Type Number Thermo 25mV 25 mV DC 0 0070 mV DC 6 Thermo 50mV 50 mV DC 0 0130 mV DC 7 8 9 4 Analog Output Calibration Model 331S Only Overview The Model 331S has one analog output which requires calibration Zero offset and gain errors are calibrated out by programming offset and gain constants to th
119. ation Command CALG A 2 0 99880 10 Send the CALSAVE command to save the constants in the E prom 11 Repeat the resistive input ranges calibration for all resistive ranges with reversal on and off 12 Repeat all of Paragraph 8 9 2 for second input if Diode Resistor Service 8 13 8 9 3 8 9 3 1 8 9 3 2 Lake Shore Model 331 Temperature Controller User s Manual Table 8 2 Calibration Table for Resistive Ranges Range Calibration Resistor Resistor Value Reversal Cal Command Nominal Value Known to Type Number 100 Plat 250 100 Q 0 0070 Q Off 100 Q Plat 250 100 Q 0 0070 Q On 10 100 Q Plat 500 500 Q 0 0270 Q Off 3 100 Q Plat 500 500 Q 0 0270 Q On 11 1000 Q Plat 5 kQ 0 520 Q Off 4 1000 Q Plat 5 kQ 0 520 Q On 12 NTC RTD 5 kQ 0 520 Q off 9 NTC RTD 5 kQ 0 520 Q On 13 Thermocouple Sensor Input Calibration Overview Each thermocouple sensor input requires calibration The sensor inputs contain multiple gain stages to accommodate the various thermocouple sensors the Model 331 supports The input circuitry is not adjusted during calibration Instead precision voltages are supplied to each input and mathematical calibration constants are calculated and programmed into the Model 331 Constants are stored to compensate for both input offset and gain errors Thermocouple inputs do not use the current source Calibration Process Sensor Input Calibration Setup Allow the Model 3
120. autions written on the storage dewar and recommended by the manufacturer be followed WARNING Liquid helium and liquid nitrogen are potential asphyxiants and can cause rapid suffocation without warning Store and use in area with adequate ventilation DO NOT vent container in confined spaces DO NOT enter confined spaces where gas may be present unless area has been well ventilated If inhaled remove to fresh air If not breathing give artificial respiration H breathing is difficult give oxygen Get medical help WARNING Liquid helium and liquid nitrogen can cause severe frostbite to the eyes or skin DO NOT touch frosted pipes or valves In case of frostbite consult a physician at once If a physician is not readily available warm the affected areas with water that is near body temperature The two most important safety aspects to consider when handling LHe and LN are adequate ventilation and eye and skin protection Although helium and nitrogen gases are non toxic they are dangerous in that they replace the air in a normal breathing atmosphere Liquid products are of an even greater threat since a small amount of liquid evaporates to create a large amount of gas Therefore it is imperative that cryogenic dewars be stored and the MTD System be operated in open and well ventilated areas Persons transferring LHe and LN should make every effort to protect eyes and skin from accidental contact with liquid or the cold gas issuing from it Prot
121. ber Main Firmware Erasable Programmable Read Only Memory EPROM U22 Contains the user interface software Has a sticker on top labeled M331F HEX and a date e Non Volatile Random Access Memory NOVRAM U23 Contains instrument settings and user curves The NOVRAM is replaced when the customer purchases a Model 8002 05 331 CalCurve Refer to Paragraph 7 2 Use the following procedure to replace any of these ICs 1 Follow the top of enclosure REMOVAL procedure in Paragraph 8 6 2 Locate the IC on the main circuit board See Figure 8 7 Note orientation of existing IC CAUTION The ICs are Electrostatic Discharge Sensitive ESDS devices Wear shock proof wrist straps resistor limited to lt 5 mA to prevent injury to service personnel and to avoid inducing an Electrostatic Discharge ESD into the device 3 Use IC puller to remove existing IC from the socket 4 Noting orientation of new IC use an IC insertion tool to place new device into socket CAUTION BH t 4 da DALLAS A 4 XXXXXXXXX L ESD XXXXXXXXX senate O 1 Match notch on Match notch on IC to notch Typical IC NOVRAM to notch Typical NOVRAM in socket in socket Eprom eps 5 Follow the top of enclosure INSTALLATION procedure in Paragraph 8 6 Service 8 7 8 7 JUMPERS There are seven jumpers located on the main circuit board of the Model 331 See Figure 8 7 for the location of the jumpers reference designators JMP1 thru JMP7 La
122. bration facility at Lake Shore for best accuracy The calibration points can be entered into the Model 331 so it can generate a curve If the CalCurve service is purchased with the calibrated sensor the curve is also generated at the factory and can be entered like any other curve 5 3 1 SoftCal With Silicon Diode Sensors Lake Shore Silicon Diode Sensors incorporate remarkably uniform sensing elements that exhibit precise monotonic and repeatable temperature response For example the Lake Shore DT 470 Series of silicon diode sensors has a repeatable temperature response from 2 K to 475 K These sensors closely follow the Standard Curve 10 response and routinely interchange with one another SoftCal is an inexpensive way to improve the accuracy of an already predictable sensor NOTE Standard Curve 10 is the name of the temperature response curve not its location inside the Model 331 Standard Curve 10 is stored in Curve Location Number 1 in the Model 331 A unique characteristic of DT 400 Series diodes is that their temperature responses pass through 28 K at almost exactly the same voltage This improves SoftCal algorithm operation by providing an extra calibration data point It also explains why SoftCal calibration specifications are divided into two temperature ranges above and below 28 K See Figure 5 1 Advanced Operation 5 7 Lake Shore Model 331 Temperature Controller User s Manual SoftCal Point 1 SoftCal Point 2 SoftCal Point 1
123. ce between the actual value of a controlled variable and the desired value corresponding to the setpoint Dewar flask A vessel having double walls the space between being evacuated to prevent the transfer of heat and the surfaces facing the vacuum being heat reflective used to hold liquid gases and to study low temperature phenomena Invented by Sir James Dewar 1842 1923 a Scottish physical chemist differential permeability The slope of a B versus H curve ua dB dH differential susceptibility The slope of a M versus H curve xa dM dH digital controller A feedback control system where the feedback device sensor and control actuator heater are joined by a digital processor In Lake Shore controllers the heater output is maintained as a variable DC current source digital data Pertaining to data in the form of digits or interval quantities Contrast with analog data dimensionless sensitivity Sensitivity of a physical quantity to a stimulus expressed in dimensionless terms The dimensionless temperature sensitivity of a resistance temperature sensor is expressed as Sa T R dR dT which is also equal to the slope of R versus T on a log log plot that is Sg d InR d InT Note that the absolute temperature in kelvin must be used in these expressions drift instrument An undesired but relatively slow change in output over a period of time with a fixed reference input Note Drift is usually expressed in percent of the
124. ceeeeeneeeeeeeaeeeeeneeeeeenaeeeeeeaaeeeeeneeeeesaeeeseeaaeeeseneeeeeenaeeeeneaeeesnneeeneaa 6 22 6 3 1 Interface Commands Alphabetical Listng eee eeeeeeeeenneeeeeeeeeeeeeaeeeeeeaeeeseneeeeneenaeeeeeenaees 6 24 7 OPTIONS AND ACCESSORIES oommccconniicinnccinsccrinerrnnn rre 7 1 7 0 GENERAL kuvina kui a itn A ee AA di 7 1 7 1 MOES deed idas 7 1 7 2 OPTIONS Ni 7 1 7 3 ACCESSORIES EERSTEN 7 2 7 4 MODEL 3003 HEATER OUTPUT CONDITIONER AA 7 4 B SERVICES EE 8 1 8 0 GENERAL ii A A id ee el tees 8 1 8 1 ELECTROSTATIC DISCHARGE oina a ie 8 1 8 1 1 Identification of Electrostatic Discharge Sensitive Components ooonooccccinocccnnoncccconannnnnnana cnn nnnnnnnnns 8 1 8 1 2 Handling Electrostatic Discharge Sensitive Components A 8 1 8 2 LINE VOLTAGE SELECTION cuca iiiis 8 2 8 3 FUSE REPLACEMENT e Meee eh Re Ser ie ee ee hi ee eee EEN 8 2 8 4 REAR PANEL CONNECTOR DEFINITIONS A 8 3 8 4 1 Serial Interface Cable Wining no nccnn nan cnnn none nc a aaan i 8 5 8 4 2 IEEE 488 Interface Connector iii a e eege e 8 6 8 5 TOP OF ENCLOSURE REMOVE AND REPLACE PROCEDURE cooococccccoconcnonononcnnnoncnonannncnnnnnnnnnnnns 8 7 8 6 FIRMWARE AND NOVRAM REPLACEMENT cccccceecceeeeeceeeeeeeeeeceeeeeeeeceaeeeeeeeceeeseeeeseeeseneeeeas 8 7 8 7 JUMPERS ci eg A Ale ee Skid is Ba ie dE i aed 8 8 8 8 ERROR MESSAGES csi tl il dia io 8 8 8 9 CALIBRATION PROCEDURE monrnon neire id aaa 8 10 8 9 1 Equipment Required for Calibration nn nn cn ncnn anna nan nnnncnns 8
125. cessories Model numbers are detailed in Paragraph 7 1 options in Paragraph 7 2 accessories in Paragraph 7 3 and the Model 3003 Heater Output Conditioner in Paragraph 7 4 7 1 MODELS The list of Model 331 Model Numbers is provided as follows Model Description Of Models Standard Temperature Controller Includes all features Model numbers as follows 3318 3318 Two Diode Resistor Inputs 331S T1 One Diode Resistor One Thermocouple Input 331S T2 Two Thermocouple Inputs Economy Temperature Controller Includes all features of the Model 331S except Relays and Analog Output 2 control loop and IEEE 488 Interface Model numbers as follows 391 KN Two Diode Resistor Inputs 331E T1 One Diode Resistor One Thermocouple Inputs 331E T2 Two Thermocouple Inputs Power Configurations The instrument is configured at the factory for customer selected power as follows VAC 100 Instrument configured for 100 VAC with U S Power Cord VAC 120 Instrument configured for 120 VAC with U S Power Cord VAC 220 Instrument configured for 220 VAC with Universal European line cord VAC 240 Instrument configured for 240 VAC with Universal European line cord VAC 120 Instrument configured for 120 VAC with U S Power Cord and universal European line ALL cord and fuses for 220 240 setting 7 2 OPTIONS The list of Model 331 options is provided as follows Model D
126. chassis ground to reduce noise For best noise performance do not connect the resistive heater or its leads to ground Also avoid connecting heater leads to sensor leads or any other instrument inputs or outputs 3 8 Installation Lake Shore Model 331 Temperature Controller User s Manual 3 7 4 3 7 5 3 7 7 Loop 1 Heater Output Noise The heater output circuitry in the Model 331 must be capable of sourcing 50 W of power This type of circuitry can generate some electrical noise The Model 331 was designed to generate as little noise as possible but even noise that is a small percentage of the output voltage or current can be too much when sensitive measurements are being made near by If the Model 331 heater leads are too noisy and the above wiring techniques do not help Lake Shore offers the Model 3003 Heater Output Conditioner that may help Refer to Paragraph 7 4 Loop 2 Output The Model 331 has a second control loop called Loop 2 Loop 2 is an auxiliary control loop with enough features to control a radiation shield or small sample heater Loop 2 has a different output from Loop 1 it uses Analog Voltage output as its actuator It is a variable DC voltage source that can vary from 0 V to 10 V The output can source up to 100 mA of current providing a maximum of 1 W of heater power Loop 2 Output Resistance 2 The power delivered by the Loop 2 output is calculated as P heater The output is rated for no more than 10
127. ck Background color Yellow Symbol and outline Black Alternating current power line Alternating or direct current power line Three phase alternating current power line Earth ground terminal Caution or Warning See instrument documentation Background color Yellow Symbol and outline Black bp p Protective conductor terminal Frame or chassis terminal On supply Off supply f Fuse O H dA Introduction 2 0 2 1 Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 2 COOLING SYSTEM DESIGN GENERAL Selecting the proper cryostat or cooling source is probably the most important decision in designing a temperature control system The cooling source defines minimum temperature cool down time and cooling power Information on choosing a cooling source is beyond the scope of this manual This chapter provides information on how to get the best temperature measurement and control from cooling sources with proper setup including sensor and heater installation Chapter 2 contains the following major topics Temperature sensor selection is covered in Paragraph 2 1 Calibrated sensors are covered in Paragraph 2 2 Sensor installation is covered in Paragraph 2 3 Heater selection and installation is covered in Paragraph 2 4 Considerations for good control are covered in Paragraph 2 5 PID Control is covered in Paragraph 2 6 Manual Tuning is covered in Paragraph 2 7 AutoTuning
128. curve number defaults to 0 Valid entries 0 none 1 20 standard curves 21 41 user curves Remarks Specifies the curve an input uses for temperature conversion Example INCRV A 23 term Input A uses User Curve 23 for temperature conversion INCRV Input Curve Number Query Input INCRV lt input gt term Format a lt input gt Specifies which input to query A or B Returned lt curve number gt term Format nn Refer to command for description INTYPE Input Type Parameter Command Input INTYPE lt input gt lt sensor type gt lt compensation gt term Format ann lt input gt Specifies input to configure A or B lt sensor type gt Specifies input sensor type Valid entries 0 Silicon Diode 5 NTC RTD 1 GaAlAs Diode 6 Thermocouple 25 mV 2 100 Q Platinum 250 7 Thermocouple 50 mV 3 100 Q Platinum 500 4 1000 Platinum lt compensation gt Specifies input compensation where O off and 1 on Reversal for thermal EMF compensation if input is resistive room compensation if input is thermocouple Always 0 if input is a diode Example INTYPE A 0 0 term Sets Input A sensor type to silicon diode 6 32 Remote Operation INTYPE Input Format Returned Format KEYST Input Returned Format Remarks KRDG Input Format Returned Format Remarks LDAT Input Format Returned Format Remarks LINEAR Input Format Example Lake Shore Model 331 Tempe
129. d load temperature If a load can reach a new setpoint in under 10 seconds with an appropriate setting gt 500 the cooling system is too fast for AutoTuning Systems with a very small thermal mass can be this fast Adding mass is a solution but is unappealing to users who need the speed for fast cycle times Manual tuning is nat difficult on these systems because new settings can be tested very quickly Some systems are too slow for the AutoTune algorithm Any system that takes more than 15 minutes to stabilize at a new setpoint is too slow with an appropriate setting lt 5 Thermal lag can be improved by using the sensor and heater installation techniques discussed above Lag times up to a few seconds should be expected much larger lags can be a problem System nonlinearity is a problem for both AutoTune and manual tuning lt is most commonly noticed when controlling near the maximum or minimum temperature of a temperature control system It is not uncommon however for a user to buy a cryogenic cooling system specifically to operate near its minimum temperature If this is the case try to tune the system at 5 degrees above the minimum temperature and gradually reduce the setpoint manually adjusting the control settings with each step Any time the mechanical cooling action of a cryogenic refrigerator can be seen as periodic temperature fluctuations the mass is too small or temperature too low to AutoTune ZONE TUNING Once the PID tuning
130. ds to the last query received Type EXIT to exit the program REM INCLUDE c gpib pc qbasic qbdecl bas CLS PRINT IEEE 488 COMMUNICATION PROGRAM PRINT CALL IBFIND dev12 DEV12 TERM CHR 13 CHR 10 INS SPACES 2000 LINE INPUT ENTER COMMAND or EXIT CMDS CMD UCASES CMD IF CMD EXIT THEN END CMD CMDS TERMS CALL IBWRT DEV12 CMDS CALL IBRD DEV12 INS ENDTEST INSTR IN CHRS 13 IF ENDTEST gt 0 THEN INS MIDS INS 1 ENDTEST 1 PRINT RESPONSE INS ELSE PRINT NO RESPONSE END IF GOTO LOOP2 Link to IEEE calls Clear screen Open communication at address 12 Terminators are lt CR gt lt LF gt Clear for return string Get command from keyboard Change input to upper case Get out on Exit Send command to instrument Get data back each time Test for returned string String is present if lt CR gt is seen Strip off terminators Print return string No string present if timeout Get next command 6 12 Remote Operation 6 1 4 5 Lake Shore Model 331 Temperature Controller User s Manual Program Operation Once either example program is running try the following commands and observe the response of the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND IDN Identification query Instrument will ret
131. dy when the Ramp feature is on blinking during a setpoint ramp Refer to Paragraph 4 12 for turning ramping on and setting the ramp rate Remote On when the instrument is in Remote mode i e may be controlled via the IEEE 488 Interface Refer to Paragraphs 4 19 and 4 20 Alarm On steady when the alarm feature is on blinking when any alarm is active Refer to Paragraph 4 15 Display Annunciators A Sensor Input A Q Sensor Units of Ohms B Sensor Input B mV Sensor Units of Millivolts S Setpoint gt Maximum Reading Value K Temperature in Kelvin lt Minimum Reading Value C Temperature in Celsius Result of Linear Equation V Sensor Units of Volts General Keypad Operation There are three basic keypad operations Direct Operation Setting Selection and Data Entry Direct Operation The key function occurs as soon as the key is pressed e g Loop Heater Off and Remote Local Setting Selection Allows the user to select from a list of values During a selection sequence the A or Y key are used to select a parameter value After a selection is made the Enter key is pressed to make the change and advance to the next setting or the Escape key is pressed to return to the normal display without changing the present setting The instrument retains any values entered prior to pressing the Escape key Some selections are made immediately after pressing a function key like Heater Range Most are part of a string of settings Setting selections al
132. e Model 331S only Local refers to operation via the front panel Refer to Paragraph 4 19 Sets the Baud rate of the serial interface and IEEE 488 address and terminators 331S Only Refer to Paragraph 4 20 Serves two functions chooses between parameters during setting operations and to increment a numerical parameter values Serves two functions chooses between parameters during setting operations and decrements numerical parameter values Terminates a setting function without changing the existing parameter value Press and hold to reset instrument to default values Refer to Paragraph 4 21 Completes setting functions and returns to normal operation Press and hold to lock or unlock keypad Refer to Paragraph 4 17 Used for entry of numeric data Includes a key to toggle plus or minus and a key for entry of a decimal point Refer to Paragraph 4 1 3 4 2 Operation Lake Shore Model 331 Temperature Controller User s Manual Annunciators LED Annunciators Six blue LED annunciators are included to provide visual feedback of the following operation Control A On when Input A is being used as the control input for the loop being displayed Refer to Paragraph 4 4 Control B On when Input B is being used as the control input for the loop being displayed Refer to Paragraph 4 4 Tune On steady when the AutoTune feature is on blinking when AutoTune is actively gathering data Refer to Paragraph 4 9 Ramp On stea
133. e coercive field The magnetic field strength H required to reduce the magnetic induction B in a magnetic material to zero coercivity generally used to designate the magnetic field strength H required to reduce the magnetic induction B in a magnetic material to zero from saturation The coercivity would be the upper limit to the coercive force Constantan A copper nickel alloy which comprises the negative lead of Type E J and T thermocouples cryogen See cryogenic fluid cryogenic Refers to the field of low temperatures usually 130 F or below as defined by 173 300 f of Title 49 of the Code of Federal Regulations cryogenic fluid A liquid that boils at temperatures of less than about 110 K at atmospheric pressure such as hydrogen helium nitrogen oxygen air or methane Also known as cryogen cryostat An apparatus used to provide low temperature environments in which operations may be carried out under controlled conditions cryotronics The branch of electronics that deals with the design construction and use of cryogenic devices Curie temperature Tc Temperature at which a magnetized sample is completely demagnetized due to thermal agitation Named for Pierre Curie 1859 1906 a French chemist current source A type of power supply that supplies a constant current through a variable load resistance by automatically varying its compliance voltage A single specification given as compliance voltage
134. e at the ramp rate A positive ramp rate is always entered and it is used by the instrument for ramps up and down in temperature The ramping feature is useful by itself but it is even more powerful when used with other features Setpoint ramps are often used with zone control mode As temperature is ramped through different temperature zones control parameters are automatically selected for best control Ramps can be initiated and status read back using a computer interface During computer controlled experiments the instrument generates the setpoint ramp while the computer is busy taking necessary data AutoTune does nat function during a setpoint ramp The ramp rate disguises the reaction of the cooling system and no valid tuning data can be taken NOTE When an incomplete ramp is shut off the setpoint will remain on the most current setting i e the reading will not jump to the end of the ramp NOTE If the input type or input curve is changed while a ramp is in progress both ramping and the heater are turned off NOTE If Ramp is on and the setpoint is set to sensor units the ramping function will remain on but when another setpoint is entered the setpoint goes directly to the new setpoint value The Ramp LED will stay on solid no blinking To enable setpoint ramping press the Control Setup key then press the Enter key until you see the following display Use the A or Y key to select Setpoint Ramp On Press the Ent
135. e good thermal conductivity They must also withstand the environmental extremes Indium foil and cryogenic grease are good examples Cooling System Design 2 5 2 3 5 2 3 6 Lake Shore Model 331 Temperature Controller User s Manual Contact Pressure When sensors are permanently mounted the solder or epoxy used to hold the sensor act as both gasket and adhesive Permanent mounting is not a good solution for everyone because it limits flexibility and can potentially damage sensors Much care should be taken not to over heat or mechanically stress sensor packages Less permanent mountings require some pressure to hold the sensor to its mounting surface Pressure greatly improves the action of gasket material to increase thermal conductivity and reduce thermal gradients A spring clamp is recommended so that different rates of thermal expansion do not increase or decrease pressure with temperature change Lead Wire Different types of sensors come with different types and lengths of electrical leads In general a significant length of lead wire must be added to the sensor for proper heat sinking and connecting to a bulk head connector at the vacuum boundary The lead wire must be a good electrical conductor but should not be a good thermal conductor or heat will transfer down the leads and change the temperature reading of the sensor Small 30 to 40 AWG wire made of an alloy like phosphor bronze is much better than copper wire Thin wire insu
136. e instrument Calibration Process 8 9 4 1 Analog Output Calibration Purpose To determine the analog output offset and gain errors and provide offset and gain calibration constants back to the Model 331 Process 1 Reset the calibration constants to their default values using the CALRSTZ and CALRSTG commands EXAMPLE Zero Offset Reset Command CALRSTZ V 1 Gain Reset Command CALRSTG V 1 2 Connect the 100 kQ resistor to the analog output Connect the positive lead of the DMM to the analog output positive terminal the negative lead is connected to the analog output negative terminal 3 Set the analog output to manual mode bipolar mode on manual output of 100 Read the output voltage with the DMM to a tolerance of 0 0010 VDC and record this negative full scale FS value 4 Determine the offset calibration constant by dividing the FS value by 10 adding 1 and then negating the result Service 8 15 Analog Output 5 Lake Shore Model 331 Temperature Controller User s Manual Calibration Continued Use the CALZ command to send the offset calibration constant EXAMPLE FS DMM Reading 10 0564 Offset Constant Calculation 10 0564 10 1 0 00564 Calibration Command CALZ V 1 0 00564 NOTE Be careful to use the formula described above and not use the same process that calibrates 6 7 the zero offset of the inputs Set the analog output to 100 Read the output voltage with the DMM to a tole
137. e instrument chassis In these cases the operators safety should remain the highest priority and low impedance from the instrument chassis to safety ground should always be maintained Installation 3 3 Lake Shore Model 331 Temperature Controller User s Manual 3 4 4 Power Switch The power switch is part of the line input assembly on the rear panel of the Model 331 and turns line power to the instrument On and Off When the circle is depressed power is Off When the line is depressed power is On 3 5 DIODE RESISTOR SENSOR INPUTS This paragraph details how to connect diode and resistor sensors to the Model 331 inputs Refer to Paragraph 4 4 to configure the inputs The optional thermocouple input is described in Paragraph 3 6 3 5 1 Sensor Input Connector and Pinout The input connectors are 6 pin DIN 45322 sockets The sensor output pins are defined in Figure 3 3 Two mating connectors 6 pin DIN plugs are included in the connector kit shipped with the instrument These are common connectors so additional mating connectors can be purchased from local electronics suppliers They can also be ordered from Lake Shore P N 106 233 NOTE Pin 3 should not be used for new installations However to match existing Model 330 or Model 340 connector wiring the definition of Pin 3 may be changed with a jumper See Figure 8 7 for jumper location To provide compatibility with sensor input connectors that have been wired for either Lake Shore
138. e to the sensor as possible This can be accomplished by putting a significant length of lead wire in thermal contact with every cooled surface between room temperature and the sensor Lead wires can be adhered to cold surfaces with varnish over a thin electrical insulator like cigarette paper They can also be wound onto a bobbin that is firmly attached to the cold surface Some sensor packages include a heat sink bobbin and wrapped lead wires to simplify heat sinking Thermal Radiation Thermal black body radiation is one of the ways heat is transferred Warm surfaces radiate heat to cold surfaces even through a vacuum The difference in temperature between the surfaces is one thing that determines how much heat is transferred Thermal radiation causes thermal gradients and reduces measurement accuracy Many cooling systems include a radiation shield The purpose of the shield is to surround the load sample and sensor with a surface that is at or near their temperature to minimize radiation The shield is exposed to the room temperature surface of the vacuum shroud on its outer surface so some cooling power must be directed to the shield to keep it near the load temperature If the cooling system does not include an integrated radiation shield or one cannot be easily made one alternative is to wrap several layers of super insulation aluminized mylar loosely between the vacuum shroud and load This reduces radiation transfer to the sample space
139. e type specified in lt X source gt Valid entries 1 a value 2 SP1 SP1 4 SP2 5 SP2 Specifies a value for b in the equation if lt B source is 1 LINEAR A 1 1 0 1 3 term The linear data for Input A is calculated from the kelvin reading of the input using the equation y 1 0 x SP1 Remote Operation 6 33 Lake Shore Model 331 Temperature Controller User s Manual LINEAR Input Linear Equation Parameter Query Input LINEAR lt input gt term Format a lt input gt Specifies which input to query A or B Returned lt equation gt lt varM value gt lt X source gt lt B source gt lt varB value gt term Format n tnnnnnn n n tnnnnnn Refer to command for description Remarks Returns input linear equation configuration LOCK Front Panel Keyboard Lock Command Input LOCK lt state gt lt code gt term Format n nnn lt state gt 0 Unlocked 1 Locked lt code gt Specifies lock out code Valid entries are 000 999 Remarks Locks out all front panel entries except pressing the Alarm key to silence alarms Refer to Paragraph 4 17 Use the CODE command to set the lock code Example LOCK 1 123 term Enables keypad lock and sets the code to 123 LOCK Front Panel Keyboard Lock Query Input LOCK term Returned lt state gt lt code gt term Format n nnn Refer to command for description MDAT Minimum Maximum Data Query Input MDAT lt input gt term Format a lt input
140. e within 0 3 of the value calculated in Step 6 Service Lake Shore Model 331 Temperature Controller User s Manual 8 9 2 3 Diode Input Ranges Calibration Purpose To determine the input offset and gain errors when the input is configured for the diode ranges and provide offset and gain calibration constants back to the Model 331 Process 1 Configure the input for the diode range to be calibrated 2 Reset the calibration constants to their default values using the CALRSTZ and CALRSTG commands EXAMPLE Input A Range GaAlAs Diode Zero Offset Reset Command CALRSTZ A 1 Gain Reset Command CALRSTG A 1 3 Short all four terminals I I V V of the input together do not tie the terminals to ground 4 Via the interface obtain the input reading using the CALREAD command and record this number 5 Program the offset calibration by negating the value read in the previous step and providing it using the CALZ command EXAMPLE Input A Range GaAlAs Diode CALREAD Reading 0 00005 Calibration Command CALZ A 1 0 00005 6 Disconnect the V terminal from the others and connect to the positive output of the voltage reference Connect the voltage reference negative output to the V I and terminals 7 Set the voltage reference to provide the calibration voltage shown in Table 8 1 Using the DMM measure the voltage to the tolerance shown in Table 8 1 8 Via the interface obtain the
141. eate solder bumps for microelectronic chip attachments and also as gaskets for pressure and vacuum sealing purposes ID 10 31 Indium Disks are 0 312 diameter x 0 005 inches ID 10 56 Indium Disks are 0 562 diameter x 0 005 inches Indium Foil Sheets Quantity 5 When used as a washer between DT 470 CU silicon diode or other temperature sensors and refrigerator cold stages indium foil increases the IF 5 thermal contact area and prevents the sensor from detaching due to vibration It also may be used as a sealing gasket for covers flanges and windows in cryogenic applications Each sheet is 0 005 x 2 x 2 inches Apiezon H Grease 25 gram Tube It is designed for general purposes where operating GAH 25 temperatures necessitate the use of a relatively high melting point grease Melting point is 523 K 250 C Can be removed using Xylene with an Isopropyl alcohol rinse ID 10 XX Accessories included with a new Model 331 7 2 Options and Accessories Lake Shore Model 331 Temperature Controller User s Manual Accessories Continued Description Of Accessories Continued Apiezon N Grease 25 gram Tube General purpose grease well suited for cryogenic use because of its low viscosity It is often used as a means of thermally anchoring cryogenic sensors as well as lubricating joints and o rings Contains high molecular weight polymeric hydrocarbon additive which gives it a tenacious rubber
142. ect Properties Window 7 Inthe Properties window use the dropdown list to select between the different controls of the current project IEEE Interface Program Bisi E 10 Set the properties of the controls as defined in Table 6 1 11 Save the program Remote Operation 6 7 Lake Shore Model 331 Temperature Controller User s Manual Table 6 1 IEEE 488 Interface Program Control Properties Current Name Property New Value Label1 Name IbIExitProgram Caption Type exit to end program Label2 Name IblCommand Caption Command Label3 Name IblResponse Caption Response Text1 Name txtCommand Text lt blank gt Text2 Name txtResponse Text lt blank gt Command1 Name cmdSend Caption Send Default True Form1 Name frmlEEE Caption IEEE Interface Program 12 Add code provided in Table 6 2 a Inthe Code Editor window under the Object dropdown list select General Add the statement Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 6 2 c Inthe Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form_Load Add the code to this subroutine as shown in Table 6 2 13 Save the program 14 Run the program The program should resemble the following ig IEEE Interface Program Al
143. ect your eyes with full face shield or chemical splash goggles Safety glasses even with side shields are not adequate Always wear special cryogenic gloves Tempshield Cryo Gloves or equivalent when handling anything that is or may have been in contact with the liquid or cold gas or with cold pipes or equipment Long sleeve shirts and cuffless trousers that are of sufficient length to prevent liquid from entering the shoes are recommended RECOMMENDED FIRST AID Every site that stores and uses LHe and LN should have an appropriate Material Safety Data Sheet MSDS present The MSDS may be obtained from the manufacturer distributor The MSDS will specify the symptoms of overexposure and the first aid to be used A typical summary of these instructions is provided as follows If symptoms of asphyxia such as headache drowsiness dizziness excitation excess salivation vomiting or unconsciousness are observed remove the victim to fresh air If breathing is difficult give oxygen If breathing has stopped give artificial respiration Call a physician immediately If exposure to cryogenic liquids or cold gases occurs restore tissue to normal body temperature 98 6 F as rapidly as possible then protect the injured tissue from further damage and infection Call a physician immediately Rapid warming of the affected parts is best achieved by bathing it in warm water The water temperature should not exceed 105 F 40 C and under no circ
144. ected loop Refer to Paragraph 4 11 A discussion of the ramp feature is provided in Paragraph 4 12 Allows entry of up to 10 temperature control zones of customer entered PID settings and Heater Ranges for the currently selected loop Refer to Paragraph 4 10 Allows manual adjustment of control parameters Proportional Integral and Derivative or Manual Heater Power MHP output for the currently selected loop Refer to Paragraph 4 8 Allows selection of sensor input type and curve Refer to Paragraph 4 4 for sensor input setup and Paragraph 4 5 for curve selection Allows entry of up to twenty 200 point CalCurves or user curves and SoftCal Refer to Chapter 5 Advanced Operation Paragraph 5 2 Front Panel Curve Entry Operations Allows the user to configure the display and select the units or other source of the readings Refer to Paragraphs 4 1 4 and 4 3 Press and hold to set display brightness Refer to Paragraph 4 18 Allows the user to configure the math features Max Min linear equation and filter Press twice to reset the stored Max Min readings Refer to Paragraph 4 14 Allows the user to configure both the alarms and relays 331S Only Refer to Paragraph 4 15 Allows the user to configure the analog output feature Also used to assign the analog output to Loop 2 control output thus enabling Loop 2 331S Only Refer to Paragraph 4 16 Sets remote or local operation Remote refers to operation is via IEEE 488 Interfac
145. emp in kelvin and R is the resistance in ohms normally closed N C A term used for switches and relay contacts Provides a closed circuit when actuator is in the free unenergized position normally open N O A term used for switches and relay contacts Provides an open circuit when actuator is in the free unenergized position O D Outer diameter oersted Oe The cgs unit for the magnetic field strength H 1 oersted 10 1 ampere meter 79 58 ampere meter ohm Q The SI unit of resistance and of impedance The ohm is the resistance of a conductor such that a constant current of one ampere in it produces a voltage of one volt between its ends open loop A control system in which the system outputs are controlled by system inputs only and no account is taken of actual system output pascal Pa The SI unit of pressure equal to 1 Nim Equal to 1 45 x 10 psi 1 0197 x 10 kgs cm 7 5 x 107 torr 4 191 x 10 inches of water or 1 x 107 bar permeability Material parameter which is the ratio of the magnetic induction B to the magnetic field strength H u B H Also see Initial Permeability and Differential Permeability platinum Pt A common temperature sensing material fabricated from pure platinum to make the Lake Shore PT family of resistance temperature sensor elements polynomial fit A mathematical equation used to fit calibration data Polynomials are constructed of finite sums of terms of the form a
146. emperature Controller User s Manual LIMITED WARRANTY Lake Shore Cryotronics Inc henceforth Lake Shore the manufacturer warrants this product to be free from defects in material and workmanship 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 Replacement or repaired parts will be warranted for only the unexpired portion of the original warranty or 90 days whichever is greater All products are thoroughly tested and calibrated to published specifications prior to shipment Calibration Certifications are offered for 12 month periods only Where such documentation must be updated a re certification service is offered by Lake Shore at a reasonable cost LIMITATION OF WARRANTY This warranty is limited to Lake Shore products purchased and installed in the United States or Internationally through our approved distribution agents This same protection will extend to any subsequent owner during the warranty period It does not apply to damage resulting from improper or inadequate maintenance unauthorized modification or misuse or operation outside of the environmental specifications It does not apply to damage caused by accident mis
147. er key You will see the following L De De p D The ramp rate is entered using the numeric keypad which includes the numbers 0 9 and decimal point The user can set a ramp rate in degrees per minute with a range of 0 to 100 and a resolution of 0 1 Ramp rate will be in the same units specified for the setpoint Press the Enter key The front panel Ramp LED will illuminate indicating the ramp function is active Any subsequent change in setpoint will ramp at the specified rate and the Ramp LED will blink while ramping is in progress If you wish to pause a ramp press the Setpoint key then immediately press the Enter key This stops the ramp at the current setpoint but leaves the ramping function activated Then to continue the ramp enter a new setpoint To turn the ramping feature off press the Control Setup key then press the Enter key until you see the following screen Use the A or Y key to select Setpoint Ramp Off Press the Enter key then the Escape key The Ramp LED will turn off Operation 4 23 4 13 Lake Shore Model 331 Temperature Controller User s Manual HEATER RANGE AND HEATER OFF Heater output for Loop 1 is a well regulated variable DC current source The Heater output is optically isolated from other circuits to reduce interference and ground loops The Heater output for the main control loop Loop 1 can provide up to 50 W of continuous power to a resistive heater load and include
148. er to command for description RAMP Control Setpoint Ramp Parameter Command Input RAMP lt loop gt lt off on gt lt rate value gt term Format n n nnnnn lt loop gt Specifies which loop to configure 1 or 2 lt off on gt Specifies whether ramping is 0 Off or 1 On lt rate value gt Specifies setpoint ramp rate in Kelvin per minute from 0 1 to 100 The rate is always positive but will respond to ramps up or down Example RAMP 1 1 10 5 term When Control Loop 1 setpoint is changed ramp the current setpoint to the target setpoint at 10 5 K minute RAMP Control Setpoint Ramp Parameter Query Input RAMP lt loop gt Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt off on gt lt rate value gt term Format n tnnnnn Refer to command for description RAMPST Control Setpoint Ramp Status Query Input RAMPST lt loop gt term Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt ramp status gt term Format n lt ramp status gt 0 Not ramping 1 Setpoint is ramping 6 36 Remote Operation RANGE Input Format RANGE Input Returned Format RDGST Input Format Returned Format Remarks RELAY Input Format Example RELAY Input Format Returned Lake Shore Model 331 Temperature Controller User s Manual Heater Range Command RANGE lt range gt term n 0 Off 1 Low 0 5 W 2 Medium 5 W 3 High 50 W Hea
149. erchange able within published tolerance bands Below is a list of Standard Curve 10 DT 470 Tolerance Accuracy Bands 305 K Bana Ae Sok ara 1 of Temp 0 1 of Temp 1 of Temp Temperatures down to 1 4 K only with a Precision Calibrated Sensor To increase accuracy perform a SoftCal with the controller and sensor After sensor calibration the custom sensor curve replaces the standard Curve 10 A Precision Option can be generated for either SoftCal or the Precision Calibration SoftCal Calibration A Lake Shore SoftCal applies only to Silicon Diodes A 2 point SoftCal takes data points at 77 35 K and 305 K A 3 point SoftCal takes data points at 4 2 K 77 35 K and 305 K Typical 2 Point Accuracy 1 0K 2 K to lt 30 K 0 25K 30K to lt 60 K 0 15K 60K to lt 345 K 0 25K 345 K to lt 375 K 1 0K 375 K to 475 K Typical 3 Point Accuracy 0 5 K 2 K to lt 30 K 0 25K 30K to lt 60K 0 15K 60K to lt 345 K 0 25K 345K to lt 375 K 1 0K 375 K to 475 K Enter voltages at the 2 or 3 data points into SoftCal capable controllers A calibration report comes with the sensor Precision Calibration Lake Shore precision calibrates most sensor types by taking up to 99 data points concentrated in areas of interest Typical silicon diode calibration accuracy is listed below Temp Typical Maximum lt 10K 12mK 20 mK 10K 12mK 20 mK 20K 15mK 25 mK 30K 25mK 45 mK 50K 30mK 55 mK 100K 25m
150. errors from room temperature compensation 0 4 uV 32 mK at 4 2 K 18 mK at 300 K 1 uV 0 05 of reading 288 mK at 4 2 K 58 mK at 300 K Calibration not available from Lake Shore 0 8 uV 64 mK at 4 2 K 36 mK at 300 K 0 4 uV 435 mK at 4 2 K 10 mK at 300 K 11 mK at 1500 K 1 uV 0 05 of reading 4 6 K at 4 2 K 38 mK at 300 K 722 mK at 1500 K Calibration not available from Lake Shore 0 8 uV 870 mK at 4 2 K 20 mK at 300 K 22 mK at 1500 K Not Recommended Recommended for Recommended for Recommended for Naf Recommended T gt 2K8B lt 19T T gt 2K8B lt 19T T gt 2K8B lt 19T Typical sensor sensitivities were taken from representative calibrations for the sensor listed 1 6 Introduction Lake Shore Model 331 Temperature Controller User s Manual 1 3 SPECIFICATIONS Thermometry Number of Inputs Input Configuration 2 Each input is factory configured as either Diode RTD or Thermocouple Diode RTD Thermocouple Measurement Type Four lead differential with current reversal Two lead room temperature compensated Excitation Constant current Not Applicable Supported Sensors Diodes Silicon GaAlAs RTDs 100 2 Platinum 1000 2 Platinum Germanium Carbon Glass Cernox ROX Thermox Most thermocouple types Standard Curves DT 470 DT 500D DT 670 PT 100 PT 1000 RX 102A RX 202A Type E Type K Type T AuFe0 07 vs Ch AuFe0 03 vs Ch
151. es Both DT 400 Series and Platinum SoftCal algorithms require a standard curve that is already present in the Model 331 When the user enters the type of sensor being calibrated the correct standard curve must be selected When calibration is complete the user must assign the new curve to an input The Model 331 does not automatically assign the newly generated curve to either input Calibration data points must be entered into the Model 331 These calibration points are normally measured at easily obtained temperatures like the boiling point of cryogens Each algorithm operates with one two or three calibration points The range of improved accuracy increases with more points There are two ways to get SoftCal calibration data points The user can record the response of an unknown sensor at well controlled temperatures or Y The user can purchase a SoftCal calibrated sensor from Lake Shore There are advantages to both methods O User When the user can provide stable calibration temperatures with the sensor installed SoftCal calibration eliminates errors in the sensor measurement as well as the sensor Thermal gradients instrument accuracy and other measurement errors can be significant to some users Calibration can be no better than user supplied data Purchased Lake Shore sensors with SoftCal calibration include a set of calibration points in the calibration report The SoftCal calibration points are generated in a controlled cali
152. es and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command strings can be chained together in one communication but they must be separated by a semi colon Only one query is permitted per communication but it can be chained to the end of a command The total communication string must not exceed 64 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting When a command is issued the computer is acting as talker and the instrument as listener The format is lt command mnemonic gt lt space gt lt parameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 6 3 Terminators must be sent with every message string A query string is issued by the computer and instructs the instrument which response to send Queries are issued similar to commands with the computer acting as talker and the instrument as listener The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in Paragraph 6 3 Terminators must be sent with every message string Issuing
153. es are stored in user curve locations 5 1 1 Curve Header Parameters Each curve has a set of parameters that are used for identification and to allow the instrument to use the curve effectively The parameters must be set correctly before a curve can be used for temperature conversion or temperature control Curve Number 1 41 Name Defaults to the name User Curve for front panel entry When entering a user curve over the computer interface a curve name of up to 15 characters can be entered Serial Number Up to a 10 character sensor serial number Both numbers and letters can be entered over computer interface only numbers can be entered from the front panel Format The format parameter tells the instrument what breakpoint data format to expect Different sensor types require different formats Formats for Lake Shore sensors are V K Volts vs Kelvin for Diode sensors Q K Resistance vs Kelvin for platinum RTD sensors Log Q K Log Resistance vs Kelvin for NTC resistive sensors Limit Enter a temperature limit in Kelvin for the curve Default is 375 K Enter a setting of 9999 K if no limit is needed Temperature Coefficient The unit derives the temperature coefficient from the first two breakpoints The user does not enter this setting If it is not correct check for proper entry of those points A positive coefficient P indicates that the sensor signal increases with increasing temperature A negative coefficient N indicat
154. es not oscillate in a controlled manner the heater range could be set too low A constant heater reading of 100 on the display would be an indication of a low range setting The heater range could also be too high indicated by rapid changes in the load temperature or heater output with a proportional setting of less than 5 There are a few systems that will stabilize and not oscillate with a very high proportional setting and a proper heater range setting For these systems setting a proportional setting of one half of the highest setting is the best choice Tuning Integral When the proportional setting is chosen and the integral is set to zero off the Model 331 controls the load temperature below the setpoint Setting the integral allows the Model 331 control algorithm to gradually eliminate the difference in temperature by integrating the error over time See Figure 2 3 d An integral setting that is too low causes the load to take too long to reach the setpoint An integral setting that is too high creates instability and cause the load temperature to oscillate Begin this part of the tuning process with the system controlling in proportional only mode Use the oscillation period of the load that was measured above in seconds Divide 1000 by the period to get the integral setting Enter the integral setting into the Model 331 and watch the load temperature approach the setpoint If the temperature does not stabilize and begins to oscillate arou
155. es that the sensor signal decreases with increasing temperature Advanced Operation 5 1 5 2 Lake Shore Model 331 Temperature Controller User s Manual Curve Breakpoints Temperature response data of a calibrated sensor must be reduced to a table of breakpoints before entering it into the instrument Each breakpoint consists of one value in sensor units and one temperature value in kelvin Linear interpolation is used by the instrument to calculate temperature between breakpoints From 2 to 200 breakpoints can be entered as a curve The instrument will show an error message on the display if the sensor input is outside the range of the breakpoints No special endpoints are required Sensor units are defined by the format setting in Table 5 2 Breakpoint setting resolution is six digits in temperature Most temperature values are entered with 0 001 resolution Temperature values of 1000 K and greater can be entered to 0 01 resolution Temperature values below 10 K can be entered with 0 0001 resolution Temperature range for curve entry is 1500 K Setting resolution is also six digits in sensor units The curve format parameter defines the range and resolution in sensor units as shown in Table 5 2 The sensor type determines the practical setting resolution Table 5 2 lists recommended sensor units resolutions For most sensors additional resolution is ignored The breakpoints should be entered with the sensor units value increasing as point
156. escription Of Options CalCurve on CD or E Mail The Model 8000 CalCurve is offered on CD or via e mail free of charge at time of order to any customer who orders a calibrated sensor The Model 8000 consists of calibration breakpoint interpolation data stored in ASCII format Also included is a PC executable program to load the data into a Lake Shore Instrument via IEEE 488 or RS 232 Interface Once loaded the instrument uses the data to calculate and display temperature The following information is included raw data coefficients interpolation table instrument breakpoints LSCurves exe DOS based program and Readme txt describing the file formats Options and Accessories 7 1 Lake Shore Model 331 Temperature Controller User s Manual Options Continued CalCurve Factory Installed Provides users with a convenient method of storing 8001 331 sensor calibrations within Lake Shore Instruments Calibration data breakpoint interpolation table for a specific sensor is stored into a nonvolatile memory CalCurve Field Installation For users who already own a Model 331 When ordering please specify your instrument serial number and calibrated sensor model and serial number A new NOVRAM will be sent for Customer installation 8002 05 331 7 3 ACCESSORIES Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit Refer to the Lake Shore Temperature Measurement and Control Catal
157. ess experienced users get started This technique will not solve every problem but it has worked for many others in the field This section assumes the user has worked through the operation sections of this manual has a good temperature reading from the sensor chosen as a control sensor and is operating Loop 1 It is also a good idea to begin at the center of the temperature range of the cooling system not close to its highest or lowest temperature AutoTune Paragraph 2 8 is another good place to begin and do not forget the power of trial and error Setting Heater Range Setting an appropriate heater output range is an important first part of the tuning process The heater range should allow enough heater power to comfortably overcome the cooling power of the cooling system If the heater range will not provide enough power the load will not be able to reach the setpoint temperature If the range is set too high the load may have very large temperature changes that take a long time to settle out Delicate loads can even be damaged by too much power Often there is little information on the cooling power of the cooling system at the desired setpoint If this is the case try the following Allow the load to cool completely with the heater off Set manual heater power output to 50 while in Open Loop control mode Turn the heater to the lowest range and write down the temperature rise if any Select the next highest heater range and continue the
158. et Integral press the PID MHP key then press Enter until you see the following display 7 The Integral reset is entered using the numeric keypad which includes the numbers 0 9 and decimal point Integral has a range of 0 1 to 1000 with a default of 20 Press the Enter key then the Escape key to return to the normal display 4 16 Operation Lake Shore Model 331 Temperature Controller User s Manual Manually Setting Derivative D The derivative parameter sometimes called rate is the D part of the PID control equation The rate time constant should normally be somewhere between 1 4 and 1 8 the integral time in seconds if used at all As a convenience to the operator the Model 331 Derivative time constant is expressed in percent of the integral time The range is between 0 and 200 Start with settings of either 0 50 or 100 and determine which setting gives you the type of control you desire Do not be surprised if the setting you prefer is 0 Note that by using a percent of integral time derivative scales automatically with changes in the integral value and does not have to be revisited frequently To set Derivative press the PID MHP key then press Enter until you see the following display The Derivative rate is entered using the numeric keypad which includes the numbers 0 9 and decimal point Derivative has a range of 0 to 200 percent with a default of O Press the Enter key
159. et the bits If a bit in the Service Request Enable Register is set 1 then that function is enabled Refer to the SRE command discussion Ramp Done Bit 7 This bit is set when the ramp is completed Service Request SRQ Bit 6 Determines whether the Model 331 is to report via the SRQ line If bits 0 3 4 5 and or 7 are set then the corresponding bit in the Status Byte Register will be set The Model 331 will produce a service request only if bit 6 of the Service Request Enable Register is set If disabled the Status Byte Register can still be read by the BUS CONTROLLER by means of a serial poll SPE to examine the status reports but the BUS CONTROLLER will not be interrupted by the Service Request The STB common command will read the Status Byte Register but will not clear the bits Standard Event Status ESB Bit 5 When bit 5 is set it indicates if one of the bits from the Standard Event Status Register has been set Refer to Paragraph 6 1 3 2 Error Bit 4 This bit is set when there is an instrument error not related to the bus Alarm Bit 3 This bit is set when there is an alarm condition New A amp B Bit 0 This bit is set when new data is available from the normal inputs Standard Event Status Register and Standard Event Status Enable Register The Standard Event Status Register reports IEEE bus status of the Model 331 STANDARD EVENT STATUS REGISTER FORMAT Ba e e AE E NA ee ee Weighting
160. etting D is related to the dominant time constant of the load similar to the lsetting and is therefore set proportional to lsetting when used Manual Heater Power MHP Output The Model 331 has a control setting that is not a normal part of a PID control loop Manual Heater Power MHP output can be used for open loop control meaning feedback is ignored and the heater output stays at the users manual setting This is a good way to put constant heating power into a load when needed The MHP output term can also be added to the PID output Some users prefer to set a power near that necessary to control at a setpoint and let the closed loop make up the small difference MHP output is set in percent of full scale current or power for a given heater range NOTE MHP output should be set to 0 when not in use 2 10 Cooling System Design Lake Shore Model 331 Temperature Controller User s Manual 3 change in setpoint 5 actual temperature response P Only too high a time P Only b P Only too low c P d P 1 D e P 331 2 3 bmp Figure 2 3 Examples of PID Control Cooling System Design 2 11 2 7 2 7 1 2 7 2 Lake Shore Model 331 Temperature Controller User s Manual MANUAL TUNING There has been a lot written about tuning closed loop control systems and specifically PID control loops This section does not attempt to compete with control theory experts It describes a few basic rules of thumb to help l
161. etup Display Location 1 detailed above the display will resemble the following De To change the setpoint units refer to Control Setup Paragraph 4 7 4 6 Operation 4 4 INPUT SETUP The Model 331 supports a variety of temperature sensors sold by Lake Shore and other manufacturers An appropriate sensor type must be selected for each of the two inputs If the exact sensor model is not shown use the sensor input performance chart in Table 4 1 to choose an input type with similar range and excitation For additional details on sensors refer to the Lake Shore Temperature Measurement and Control Catalog or visit our website at www lakeshore com Table 4 1 Sensor Input Types Lake Shore Model 331 Temperature Controller User s Manual Display Message Input Excitation Sensor Type Curve Coefficient Lake Shore Sensors Range Format Silicon Diode 2 5V 10 pA Silicon Diode VIK Negative DT 4XX DT 500 DT 670 Series GaAlAs Diode 75V wu Salllum Aluminum VIK Negative TG 120 Series Arsenide Diode 1000 Plati250 2509 1ma 100 0Plat RTD lt 675K PT 100 Series Platinum Rhodium lron RTD QIK Positive RF 800 Rhodium lron 100Q Plat 500 500 Q 1mA 100 Q Plat RTD gt 675K 10000 Plat 5000 Q 1 mA 1000 2 Plat RTD Q K Positive Cernox High Temperature Negative Temperature Cernox Carbon Glass MORID aa P Coefficient NTC RTD PRESSE Germanium Rox and Thermox
162. f Terminology A 1 Lake Shore Model 331 Temperature Controller User s Manual autotuning In Lake Shore Temperature Controllers the Autotuning algorithm automatically determines the proper settings for Gain Proportional Reset Integral and Rate Derivative by observing the time response of the system upon changes in setpoint B Symbol for magnetic flux density See Magnetic Flux Density bar Unit of pressure equal to 10 pascal or 0 98697 standard atmosphere Baud A unit of signaling speed equal to the number of discrete conditions or signal events per second or the reciprocal of the time of the shortest signal element in a character bel B A dimensionless unit expressing the ration of two powers or intensities or the ratio of a power to a reference power such that the number of bels is the common logarithm of this ratio bifilar windings A winding consisting of two insulated wires side by side with currents traveling through them in opposite directions bit A contraction of the term binary digit a unit of information represented by either a zero or a one BNC Bayonet Nut Connector boiling point The temperature at which a substance in the liquid phase transforms to the gaseous phase commonly refers to the boiling point at sea level and standard atmospheric pressure CalCurve Service The service of storing a mathematical representation of a calibration curve on an EEPROM or installed in a Lake Shore
163. f the samples magnetization magnetic induction B See magnetic flux density magnetic moment m This is the fundamental magnetic property measured with dc magnetic measurements systems such as a vibrating sample magnetometer extraction magnetometer SQUID magnetometer etc The exact technical definition relates to the torque exerted on a magnetized sample when placed in a magnetic field Note that the moment is a total attribute of a sample and alone does not necessarily supply sufficient information in understanding material properties A small highly magnetic sample can have exactly the same moment as a larger weakly magnetic sample see Magnetization Measured in SI units as Am and in cgs units as emu 1 emu 10 Am magnetic units Units used in measuring magnetic quantities Includes ampere turn gauss gilbert line of force maxwell oersted and unit magnetic pole magnetization M This is a material specific property defined as the magnetic moment m per unit volume V M m V Measured in SI units as A m and in cgs units as emu cm 1 emu cm 10 A m Since the mass of a sample is generally much easier to determine than the volume magnetization is often alternately expressed as a mass magnetization defined as the moment per unit mass material safety data sheet MSDS OSHA Form 20 contains descriptive information on hazardous chemicals under the OSHA Hazard Communication Standard HCS These data sheets also provide precaut
164. f water 273 15 K 0 C 32 F Absolute zero OK 273 15 C 459 67 F kelvin Celsius Fahrenheit Figure B 1 Temperature Scale Comparison CONVERSIONS To convert Fahrenheit to Celsius subtract 32 from F then divide by 1 8 or C F 32 1 8 To convert Celsius to Fahrenheit multiply C by 1 8 then add 32 or F 1 8 x C 32 To convert Fahrenheit to kelvin first convert F to C then add 273 15 To convert Celsius to kelvin add 273 15 Temperature Scales B 1 273 15 270 267 78 267 59 263 15 262 22 262 04 260 256 67 256 48 253 15 251 11 250 93 250 245 56 245 37 243 15 240 239 82 234 44 234 26 233 15 230 228 89 228 71 223 33 223 15 220 217 78 217 59 213 15 212 22 212 04 210 206 67 206 48 203 15 201 11 200 93 200 195 56 195 37 193 15 190 189 82 184 44 184 26 183 15 Lake Shore Model 331 Temperature Controller User s Manual Table B 1 Temperature Conversion Table B 2 Temperature Scales C1 0 C2 0 C3 0 Lake Shore Model 331 Temperature Controller User s Manual APPENDIX C HANDLING LIQUID HELIUM AND NITROGEN GENERAL Use of liquid helium LHe and liquid nitrogen LN is often associated with the Model 331 Temperature Controller Although not explosive there are a number of safety considerations to keep in mind in the handling of LHe and LN PROPERTIES LHe and LN are colorless odorles
165. fect of most error sources Install the sensor properly following guidelines in Paragraph 2 3 Have the sensor and instrument periodically recalibrated or in some other way null the time dependent errors Use a sensor calibration that is appropriate for the accuracy requirement Sensor Package Many types of sensors can be purchased in different packages Some types of sensors can even be purchased as bare chips without any package A sensor package generally determines its size thermal and electrical contact to the outside and sometimes limits temperature range When different packages are available for a sensor the user should consider the mounting surface for the sensor and how leads will be heat sinked when choosing CALIBRATED SENSORS There can sometimes be confusion in the difficult task of choosing the right sensor getting it calibrated translating the calibration data into a temperature response curve that the Model 331 can understand then getting the curve loaded into the instrument Lake Shore provides a variety of calibration and curve loading services to fit different accuracy requirements and budgets Traditional Calibration Calibration is done by comparing a sensor with an unknown temperature response to an accepted standard Lake Shore temperature standards are traceable to the U S National Institute of Standards and Testing NIST or the National Physical Laboratory in Great Britain These standards allow Lake Shore to cal
166. for either input or manual Detachable terminal block Analog Voltage Output Model 331S Only Scale Update Rate Data Source Settings Range Resolution Accuracy Minimum Load Resistance User selected 10 readings per second Temperature Sensor Units Linear Equation Input Source Top of scale Bottom of scale or manual 10 V 0 3 mV 2 5 mV 100 Q short circuit protected 1 8 Introduction Lake Shore Model 331 Temperature Controller User s Manual Specifications Continued General Ambient Temperature 15 35 C at rated accuracy 10 40 C at reduced accuracy Power Requirement 100 120 220 240 VAC 5 10 50 or 60 Hz 120 VA Size 217 mm wide x 90 mm high x 317 mm deep 8 5 x 3 5 x 14 5 inches half rack Weight 4 8 kilograms 10 5 pounds Ordering Information Part Number Description Input configuration cannot be changed in the field Standard Temperature Controllers all features included 331S Two Diode Resistor Inputs 331S T1 One Diode Resistor One Thermocouple Input 331S T2 Two Thermocouple Inputs Economy Temperature Controllers all features of the 331S except does not include the following IEEE 488 relays analog voltage output second control loop 331E Two Diode Resistor Inputs 331E T1 One Diode Resistor One Thermocouple Input 331E T2 Two Thermocouple Inputs Refer to Chapter 7 of this manual for a complete description of Model 331 options and accessories Specificat
167. for the application Other parameters fall into place once these have been chosen 4 6 1 Control Loops The Model 331 is capable of running either one 331E or two simultaneous 331S control loops Their capabilities are compared in Table 4 3 As shown there the primary difference between the two loops is their control output Loop 1 Loop 1 the primary control loop is the traditional control loop for a cryogenic temperature controller It includes the largest set of hardware and software features making it very flexible and easy to use Loop 1 uses the heater output as its control output giving it several advantages The heater output is a well regulated 50 W DC output with three power ranges This provides quiet stable control for a broad range of temperature control systems in a fully integrated package Loop 2 Loop 2 the auxiliary control loop 331S only shares most of the operational features of loop 1 but uses the 1 W analog voltage output as its control output By itself loop 2 is capable of driving a sample heater or other low power load It is also well suited to drive the programming input of a voltage programmable power supply In combination the controller and supply can be used to control large loads at high temperatures or can be used in bipolar mode to control thermoelectric devices The keypad and display operate on one loop at a time To toggle display and keypad operation between loop 1 and loop 2 press the Loop key to tog
168. fy the shipping agent immediately Open the shipping containers A packing list is included with the system to simplify checking that the instrument sensor s accessories and manual were received Please use the packing list and the spaces provided to check off each item as the instrument is unpacked Inspect for damage Be sure to inventory all components supplied before discarding any shipping materials If there is damage to the instrument in transit be sure to file proper claims promptly with the carrier and insurance company Please advise Lake Shore Cryotronics of such filings In case of parts or accessory shortages advise Lake Shore immediately Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment The standard Lake Shore Warranty is included on the A Page immediately behind the title page of this manual REPACKAGING FOR SHIPMENT If it is necessary to return the Model 331 sensor s or accessories for recalibration repair or replacement a Return Goods Authorization RGA number must be obtained from a factory representative before returning the instrument to our service department When returning an instrument for service the following information must be provided before Lake Shore can attempt any repair Instrument model and serial number User s name company address and phone number Malfunction symptoms Description of system 5 Returned Goods Authorization RGA number B
169. ges to see if better parameter values are calculated To select an AutoTune mode press the AutoTune key and press either the A V or AutoTune key to cycle the display to AutoTune PID You will see the following display E TI be UH We Use the A or Y key to cycle between Auto PID Auto PI and Auto P Press the Enter key The controller is now in Autotuning mode When the AutoTune feature is on the front panel Tune LED will be on steady When there is a setpoint change and the Model 331 is actively gathering data the Tune LED will blink 4 18 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 10 ZONE SETTINGS Closed Loop Control Mode The Model 331 allows the user to establish up to 10 custom contiguous temperature zones where the controller will automatically use pre programmed PID values and heater ranges Zone control can be active for both control loops at the same time The user should configure the zones using 01 as the lowest to 10 as the highest zone Zone boundaries are always specified in kelvin K The bottom of the first zone is always 0 K therefore only the upper limit is required for all subsequent zones Make a copy of Figure 4 4 to plan your zones Once all zone parameters have been programmed the controller must be placed in zone tuning mode To do this press the AutoTune key Use the A or W key to select Zone Then press Enter to accept the new tuning mode Once zone is tu
170. gle the display and keypad operation between Loop 1 and 2 A brief display message indicates which control loop has been selected You can determine which loop is active by looking at the heater output display Loop 1 has Low Med or High in the heater display Loop 2 has L2 in the heater display Also when you select any of the following parameters the active loop number will be displayed Control Setup Setpoint PID MHP Zone Settings AutoTune and Heater Range Table 4 3 Comparison of Control Loops 1 and 2 Loop 2 Feature Loopt rose ony Operation 4 13 Lake Shore Model 331 Temperature Controller User s Manual 4 6 2 4 6 3 4 7 Control Modes The Model 331 offers two control modes closed loop and open loop To select a control mode refer to Paragraph 4 7 Closed Loop Control Closed loop control often called feedback control is the control mode most often associated with temperature controllers In this mode the controller attempts to keep the load at exactly the user entered setpoint temperature To do this it uses feedback from the control sensor to calculate and actively adjust the control output or heater setting The Model 331 uses a control algorithm called PID that refers to the three terms used to tune the controller for each unique system Manual heater power output can also be used during closed loop control Closed loop control is available for both control loops and offers severa
171. gs IDN Identification Query Input IDN term Returned lt manufacturer gt lt model gt lt serial gt lt date gt term Format aaaa aaaaaaaa aaaaaa mmddyy lt manufacture gt Manufacturer ID lt model gt Instrument model number lt serial gt Serial number lt date gt Instrument firmware revision date Example LSCI MODEL331S 123456 020399 6 24 Remote Operation OPC Input Remarks OPC Input Returned Remarks RST Input Remarks SRE Input Format Remarks Example SRE Input Returned Format STB Input Returned Format Remarks Lake Shore Model 331 Temperature Controller User s Manual Operation Complete Command OPC term Generates an Operation Complete event in the Event Status Register upon completion of all pending selected device operations Send it as the last command in a command string Operation Complete Query OPC term 1 term Places a 1 in the controller output queue upon completion of all pending selected device operations Send as the last command in a command string Not the same as OPC Reset Instrument Command RST term Sets controller parameters to power up settings Service Request Enable Register Command SRE lt bit weighting gt term nnn Each bit has a bit weighting and represents the enable disable mask of the corresponding status flag bit in the Status Byte Register To enable a status flag bit send the command SR
172. gt Specifies the control mode Valid entries 1 Manual PID 2 Zone 3 Open Loop 4 AutoTune PID 5 AutoTune PI 6 AutoTune P Example CMODE 1 4 term Control Loop 1 uses PID AutoTuning CMODE Control Loop Mode Query Input CMODE lt loop gt term Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt mode gt term Format n Refer to command for description CRDG Celsius Reading Query Input CRDG lt input gt term Format a lt input gt AorB Returned lt temp value gt term Format nnnnnn Remarks Also see the RDGST command CRVDEL Curve Delete Command Input CRVDEL lt curve gt term Format nn lt curve gt Specifies a user curve to delete Valid entries 21 41 Example CRVDEL 21 term Deletes User Curve 21 6 28 Remote Operation CRVHDR Input Format Remarks Example Lake Shore Model 331 Temperature Controller User s Manual Curve Header Command CRVHDR lt curve gt lt name gt lt SN gt lt format gt lt limit value gt lt coefficient gt term nn aaaaaaaaaaaaaaa aaaaaaaaaa n nnn nnn n lt curve gt Specifies which curve to configure Valid entries 21 41 lt name gt Specifies curve name Limited to 15 characters lt SN gt Specifies the curve serial number Limited to 10 characters lt format gt Specifies the curve data format Valid entries 1 mV K 2 V K 3 Q K 4 log Q K lt limit value gt Specifies the curve temperature limi
173. h 2 7 To place the controller in Manual PID tuning mode press the AutoTune key and press the A or Y key until you see the following display Press the Enter key The controller is now in Manual PID mode Manually Setting Proportional P The proportional parameter also called gain is the P part of the PID control equation It has a range of 0 to 1000 with a resolution of 0 1 Enter a value greater than zero for P when using closed loop control To set Proportional press the PID MHP key You will see the following display The Proportional gain limit is entered using the numeric keypad which includes the numbers 0 9 and decimal point Proportional has a range of 0 1 to 1000 with a default of 50 Press the Enter key then the Escape key to return to the normal display Manually Setting Integral I The integral parameter also called reset is the part of the PID control equation It has a range of 0 to 1000 with a resolution of 0 1 Setting to zero turns the reset function off The setting is related to seconds by _ 1000 setting I I seconds For example a reset number setting of 20 corresponds to a time constant of 50 seconds A system will normally take several time constants to settle into the setpoint The 50 second time constant if correct for the system being controlled would result in a system that stabilizes at a new setpoint in between 5 and 10 minutes To s
174. h 4 7 and the active control loop is selected Paragraph 4 6 1 the desired heater range is selected by pressing the Heater Range key p E Use the A or Y key to cycle through Loop 1 Heater settings Off Low Med and High Once the desired heater setting is displayed press the Enter key You will return to the normal display For the Model 331S only use the A or Y key to toggle between Loop 2 Heater settings Off and On Once the desired heater setting is displayed press the Enter key You will return to the normal display NOTE If the display shows Heater Disabled the analog output is not properly configured to work as a control loop Refer to Paragraph 4 16 To immediately turn the heater off press the Heater Off key If the Heater Range is not being displayed on the front panel the user should immediately press the Heater Range key to verify that the proper loop is displayed and the heater shows Off 4 24 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 14 MATH Three math features are included for convenience and aid in setting up experiments Max and Min readings can be captured A linear equation can be applied to input data to correct system errors or improve performance of the analog outputs Readings can be filtered to quiet effects of a noisy environment These math features can be performed on both sensor inputs however each input must be configured separately When you f
175. he Remote LED will be On INTERFACE The Interface key serves three functions set the Serial Interface Baud rate set the IEEE 488 Interface Address and Terminators Model 331S Only and select the Model 330 Emulation Mode To set the Serial Interface Baud rate press the Interface key Use the A or Y key to cycle through the choices of 300 1200 and 9600 Baud The default Baud rate is 9600 Press the Enter key to accept the changes or the Escape key to keep the existing setting and return to the normal display On the Model 331S only to set the IEEE 488 Interface Address and Terminators press the Interface key then press the Enter key until you see the following screen mns lz Use the A or Y key to increment or decrement the IEEE Address to the desired number The default address is 12 Press the Enter key to accept the changes or the Escape key to keep the existing setting and return to the normal display Press the Enter key again to see the following screen Lie L 1 or UL LEI an Operation Lake Shore Model 331 Temperature Controller User s Manual Interface Continued Use the A or Y key to cycle through the following Terminator choices Cr Lf Lf Cr Lf or EOI where Cr Carriage Return Lf Line Feed and EOI End Or Identify The default terminator is Cr Lf Press the Enter key to accept the changes and continue to the next screen or the Escape key to keep
176. he constant current that if maintained in two straight parallel conductors of infinite length of negligible circular cross section and placed one meter apart in a vacuum would produce between these conductors a force equal to 2 x 10 newton per meter of length This is one of the base units of the SI ampere turn A MKS unit of magnetomotive force equal to the magnetomotive force around a path linking one turn of a conducting loop carrying a current of one ampere or 1 26 gilberts ampere meter A m The SI unit for magnetic field strength H 1 ampere meter 41 1000 oersted 0 01257 oersted analog controller A feedback control system where there is an unbroken path of analog processing between the feedback device sensor and control actuator heater analog data Data represented in a continuous form as contrasted with digital data having discrete values analog output A voltage output from an instrument that is proportional to its input For example from a digital voltmeter the output voltage is generated by a digital to analog converter so it has a discrete number of voltage levels anode The terminal that is positive with respect to the other terminal when the diode is biased in the forward direction Anode B Cathode asphyxiant gas A gas which has little or no positive toxic effect but which can bring about unconsciousness and death by displacing air and thus depriving an organism of oxygen Glossary o
177. he fuse drawer window shows the appropriate AC line voltage before turning the instrument on The instrument may be damaged if turned on with the wrong voltage selected Instructions for changing the line voltage configuration are given in Paragraph 8 2 Line Fuse and Fuse Holder The line fuse is an important safety feature of the Model 331 If a fuse ever fails it is important to replace it with the value and type indicated on the rear panel for the line voltage setting The letter T on the fuse rating indicates that the instrument requires a time delay or slow blow fuse Fuse values should be verified any time line voltage configuration is changed Instructions for changing and verifying a line fuse are given in Paragraph 8 3 Power Cord The Model 331 includes a 3 conductor power cord that mates with the IEC 320 C14 line cord receptacle Line voltage is present on the two outside conductors and the center conductor is a safety ground The safety ground attaches to the instrument chassis and protects the user in case of a component failure A CE approved power cord is included with instruments shipped to Europe a domestic power cord is included with all other instruments unless otherwise specified when ordered Always plug the power cord into a properly grounded receptacle to ensure safe instrument operation The delicate nature of measurement being taken with this instrument may necessitate additional grounding including ground strapping of th
178. high vacuum used to insulate cryostats is one source of problems Materials used in these applications should have a low vapor pressure so they do not evaporate or out gas and spoil the vacuum insulation Metals and ceramics do not have this problem but greases and varnishes must be checked Another source of problems is the wide extremes in temperature most sensors are exposed to The linear expansion coefficient of a materials becomes important when temperature changes are so large Never try to permanently bond materials with linear expansion coefficients that differ by more than three A flexible mounting scheme should be used or the parts will break apart potentially damaging them The thermal expansion or contraction of rigid clamps or holders could crush fragile samples or sensors that do not have the same coefficient Thermal conductivity is a property of materials that can change with temperature Do not assume that a heat sink grease that works well at room temperature and above will do the same job at low temperatures Sensor Location Finding a good place to mount a sensor in an already crowded cryostat is never easy There are less problems if the entire load and sample holder are at the same temperature Unfortunately this not the case in many systems Temperature gradients differences in temperature exist because there is seldom perfect balance between the cooling source and heat sources Even in a well controlled system unwanted heat s
179. ibrate sensors from 50 mK to above room temperature Calibrated sensors are more expensive than uncalibrated sensors of the same type because of the labor and capitol equipment used in the process This type of calibration provides the most accurate temperature sensors available from Lake Shore Errors from sensor calibration are almost always smaller than the error contributed by the Model 331 The Lake Shore Temperature Measurement and Control Catalog has complete accuracy specifications for calibrated sensors 2 2 Cooling System Design Lake Shore Model 331 Temperature Controller User s Manual Traditional Calibration Continued 2 2 2 2 2 3 2 2 4 Calibrated sensors include the measured test data printed and plotted the coefficients of a Chebychev polynomial that has been fitted to the data and two tables of data points to be used as interpolation tables Both interpolation tables are optimized to allow accurate temperature conversion The smaller table called a breakpoint interpolation table is sized to fit into instruments like the Model 331 where it is called a temperature response curve Getting a curve into a Model 331 may require a CalCurve described below or hand entering through the instrument front panel It is important to look at instrument specifications before ordering calibrated sensors A calibrated sensor is required when a sensor does not follow a standard curve if the user wishes to display in temperature
180. ic pressure See Temperature for conversions feedback control system A system in which the value of some output quantity is controlled by feeding back the value of the controlled quantity and using it to manipulate an input quantity so as to bring the value of the controlled quantity closer to a desired value Also known as closed loop control system four lead measurement technique where one pair of excitation leads and an independent pair of measurement leads are used to measure a sensor This method reduces the effect of lead resistance on the measurement GaAlAs Gallium aluminum arsenide semiconducting material used to make the special Lake Shore TG family of diode temperature sensors gamma A cgs unit of low level flux density where 100 000 gamma equals one oersted or 1 gamma equals 10 oersted gauss G The cgs unit for magnetic flux density B 1 gauss 10 tesla Named for Karl Fredrich Gauss 1777 1855 a German mathematician astronomer and physicist gaussian system units A system in which centimeter gram second units are used for electric and magnetic qualities general purpose interface bus GPIB Another term for the IEEE 488 bus germanium Ge A common temperature sensing material fabricated from doped germanium to make the Lake Shore GR family of resistance temperature sensor elements Glossary of Terminology A 3 Lake Shore Model 331 Temperature Controller User s Manual gilbert Gb A cgs electromagnetic
181. input gt Specifies which input for which to reset the zero offset calibration constant to the default value Valid entries are A or B for inputs and V for the analog output lt type gt Specifies the input sensor type Valid entries are 0 Silicon Diode 6 Thermo 25mV 1 GaAlAs Diode or Analog Output 7 Thermo 50mV 2 1000 Plat 250 Reversal Off 10 100 Plat 250 Reversal On 3 100Q Plat 500 Reversal Off 11 1000 Plat 500 Reversal On 4 10000 Plat Reversal Off 12 1000Q Plat Reversal On 5 NTC RTD Reversal Off 13 NTC RTD Reversal On Remarks Resets the zero offset calibration constant for a specific input and type to its default value CALSAVE Calibration Save Command Input CALSAVE term Remarks Saves all CALZ and CALG calibration constants to the E prom CALZ Zero Offset Calibration Constant Command Input CALZ lt input gt lt type gt lt value gt term Format a nn tnnnnnnn lt input gt Specifies which input or analog output the zero offset calibration constant will be provided to Valid entries are A or B for inputs and V for the analog output lt type gt Specifies the input sensor type Valid entries are 0 Silicon Diode 6 Thermo 25mV 1 GaAlAs Diode or Analog Output 7 Thermo 50mV 2 1000 Plat 250 Reversal Off 10 100 Plat 250 Reversal On 3 100Q Plat 500 Reversal Off 11 1000 Plat 500 Reversal On 4 10000 Plat Reversal Off 12 1000Q Plat Reversal On 5
182. input reading using the CALREAD command and record this number 9 Program the gain calibration by dividing the measured value of the reference voltage by the value read in the previous step and provide the result using the CALG command Note that the gain calibration constant will always be within 5 of 1 00000 EXAMPLE Input A Range GaAlAs Diode Measured Value of Reference Voltage 7 50002 VDC CALREAD Reading 7 49852 Constant Calculation 7 50002 7 49852 1 00020 Calibration Command CALG A 1 1 00020 10 Send the CALSAVE command to save the constants in the E prom 11 Perform calibration on both diode ranges Table 8 1 Calibration Table for Diode Ranges Range Voltage Reference Output Reference Voltage Known To Cal Command Type Number Silicon Diode 2 5 VDC 0 00010 VDC GaAlAs Diode 7 5 VDC 0 00040 VDC 1 8 12 Service Lake Shore Model 331 Temperature Controller User s Manual 8 9 2 4 Resistive Input Ranges Calibration Purpose To determine the input offset and gain errors when the input is configured for the resistive ranges and provide offset and gain calibration constants back to the Model 331 This step will calibrate all resistive ranges with reversing both on and off Process 1 Configure the input for the resistive range to be calibrated 2 Reset the calibration constants to their default values using the CALRSTZ and CALRSTG
183. ins common interface command 2 Required to identify queries aa String of alpha numeric characters nn String of number characters that may include a decimal point term Terminator characters lt gt Indicated a parameter field many are command specific lt state gt Parameter field with only On Off or Enable Disable states lt value gt Floating point values have varying resolution depending on the type of command or query issued 6 22 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Table 6 8 Command Summary Command Function Page Command Function Page CLS Clear Interface Cmd 24 HTRST Heater Status Query 31 ESE Event Status Enable Cmd ccoo 24 IEEE IEEE Interface Parameter Cmd 32 ESE Event Status Enable Query 24 IEEE IEEE Interface Parameter Query 32 ESR Event Status Register Query 24 INCRV Input Curve Number Cmd ee 32 IDN Identification Query 24 INCRV Input Curve Number Query sses 32 OPC Operation Complete Cmd o 25 INTYPE Input Type Parameter Cmd 000 32 OPC Operation Complete Query 25 INTYPE Input Type Parameter Query 33 RST Reset Instrument Cmd ee 25 KEYST Keypad Status Query ece 33 SRE Service Request Enable Cmd 25 KRDG Kelvin Reading COuenm 33 SRE Service Request Enable Query 25 LDAT Linear
184. instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously locked out with the LLO command SPE Serial Poll Enable and SPD Serial Poll Disable Serial polling accesses the Service Request Status Byte Register This status register contains important operational information from the unit requesting service The SPD command ends the polling sequence Common Commands Common Commands are addressed commands which create commonalty between instruments on the bus All instruments that comply with the IEEE 488 1987 standard share these commands and their format Common commands all begin with an asterisk They generally relate to bus and instrument status and identification Common query commands end with a question mark Model 331 common commands are detailed in Paragraph 6 3 and summarized in Table 6 8 Device Specific Commands Device specific commands are addressed commands The Model 331 supports a variety of device specific commands to program instruments remotely from a digital computer and to transfer measurements to the computer Most device specific commands perform functions also performed from the front panel Model 331 device specific commands are detailed in Paragraph 6 3 and summarized in Table 6 8 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queri
185. ion where these tools are available 6 2 7 1 Visual Basic Serial Interface Program Setup The serial interface program works with Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better with a serial interface lt uses the COM1 communications port at 9600 Baud Use the following procedure to develop the Serial Interface Program in Visual Basic Start VB6 Choose Standard EXE and select Open Resize form window to desired size On the Project Menu click Components to bring up a list of additional controls available in VB6 Scroll through the controls and select Microsoft Comm Control 6 0 Select OK In the toolbar at the left of the screen the Comm Control will have appeared as a telephone icon Select the Comm control and add it to the form 7 Add controls to form a Add three Label controls to the form b Add two TextBox controls to the form c Add one CommandButton control to the form d Add one Timer control to the form 8 On the View Menu select Properties Window 9 Inthe Properties window use the dropdown list to select between the different controls of the current project SANS o Label Command Label3 Label 10 Set the properties of the controls as defined in Table 6 5 11 Save the program Remote Operation 6 17 Lake Shore Model 331 Temperature Controller User s Manual Table 6 5 Serial Interface Progr
186. ionary information on the safe handling of the gas as well as emergency and first aid procedures microcontroller A microcomputer microprocessor or other equipment used for precise process control in data handling communication and manufacturing MKSA System of Units A system in which the basic units are the meter kilogram and second and the ampere is a derived unit defined by assigning the magnitude An x 107 to the rationalized magnetic constant sometimes called the permeability of space NBS National Bureau of Standards Now referred to as NIST negative temperature coefficient NTC Refers to the sign of the temperature sensitivity For example the resistance of a NTC sensor decreases with increasing temperature National Institute of Standards and Technology NIST Government agency located in Gaithersburg Maryland and Boulder Colorado that defines measurement standards in the United States Glossary of Terminology A 5 Lake Shore Model 331 Temperature Controller User s Manual noise electrical Unwanted electrical signals that produce undesirable effects in circuits of control systems in which they occur normalized sensitivity For resistors signal sensitivity dR dT is geometry dependent i e dR dT scales directly with R consequently very often this sensitivity is normalized by dividing by the measured resistance to give a sensitivity st in percent change per kelvin st 100 R dR dT K where T is the t
187. ions subject to change without notice 1 4 SAFETY SUMMARY Observe these general safety precautions during all phases of instrument operation service and repair Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended instrument use Lake Shore Cryotronics Inc assumes no liability for Customer failure to comply with these requirements The Model 331 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instrument Environmental conditions outside of the conditions below may pose a hazard to the operator and surrounding area e Indoor use e Altitude to 2000 meters e Temperature for safe operation 5 C to 40 C e Maximum relative humidity 80 for temperature up to 31 C decreasing linearly to 50 at 40 C e Power supply voltage fluctuations not to exceed 10 of the nominal voltage e Overvoltage category Il e Pollution degree 2 Ground The Instrument To minimize shock hazard the instrument is equipped with a three conductor AC power cable Plug the power cable into an approved three contact electrical outlet or use a three contact adapter with the grounding wire green firmly connected to an electrical ground safety ground at the power outlet The power jack and mating plug of the power cable meet Underwriters Laboratories UL and Inter
188. irst press the Math key you will see the following display Press the Math key again to reset the stored maximum and minimum values This does not reset the math settings it only resets the data that has been collected since the function was initiated or since the last math reset The controller will return to the normal display Otherwise press the Enter key to continue to the math settings The first screen appear as follows Use the A or Y key to toggle between Input A and B Press the Enter key to accept or press the Escape key to cancel the entry and return to the normal display All subsequent math functions will be set for the selected input The following paragraphs detail the math settings in order of appearance 4 14 1 Max Min The Max Min feature captures and stores the highest Max and lowest Min reading taken since the last reset The feature will only capture from one reading source at a time for each input Temp K Temp C Sensor and Linear selection determines the source for the selected sensor input TempK Kelvin temperature reading from input Temp C Celsius temperature reading from input Sensor Sensor units V mV or Q reading from input Linear Linear equation data from input Max and Min are always being captured so there is no need to turn the feature on or off The readings are reset when the instrument is turned off parameters related to the input are changed or the Math Re
189. is covered in Paragraph 2 8 Finally Zone Tuning is covered in Paragraph 2 9 TEMPERATURE SENSOR SELECTION This section attempts to answer some of the basic questions concerning temperature sensor selection Additional useful information on temperature sensor selection is available in the Lake Shore Temperature Measurement and Control Catalog The catalog has a large reference section that includes sensor characteristics and sensor selection criteria Temperature Range Several important sensor parameters must be considered when choosing a sensor The first is temperature range The experimental temperature range must be known when choosing a sensor Some sensors can be damaged by temperatures that are either too high or too low Manufacturer recommendations should always be followed Sensor sensitivity is also dependent on temperature and can limit the useful range of a sensor It is important not to specify a range larger than necessary If an experiment is being done at liquid helium temperature a very high sensitivity is needed for good measurement resolution at that temperature That same resolution may not be required to monitor warm up to room temperature Two different sensors may be required to tightly cover the range from helium to room temperature but lowering the resolution requirement on warm up may allow a less expensive one sensor solution Another thing to consider when choosing a temperature sensor is that instruments like the
190. isable means the controller will always power up with the heater off no matter how it was set when power was turned off To change the Power Up parameter press the Control Setup key and press Enter until the following display appears Use the A or Y key to toggle between Power Up Enable or Disable Press the Enter key The Model 331 will display the heater output as either percent of full scale current or percent of full scale power for the heater range selected for Loop 1 For Loop 2 the control output is always reported in percent of full scale voltage and this parameter will not appear in the Control Setup menu This parameter affects the heater output display and the scale of the Manual Heater Power MHP output parameter for Loop 1 The MHP Output scale is always the same as the control output display To change control output units press the Control Setup key and press Enter until the following display appears Use the A or Y key to toggle between Heater Out Power or Current Press the Enter key Operation 4 15 4 8 4 8 1 4 8 2 Lake Shore Model 331 Temperature Controller User s Manual MANUAL TUNING Closed Loop PID Control In manual PID mode the controller will accept user entered Proportional Integral and Derivative parameters to provide three term PID control Manual heater power output can be set manually in open loop and closed loop control modes For details on PID tuning refer to Paragrap
191. isplayed refer to Paragraph 8 8 for details The Model 331 should now be controlling the temperature in the experimental setup at the setpoint temperature Once this initial checkout procedure is successfully completed the unit is ready for normal operation We recommend all users thoroughly read Chapter 4 Operation before attempting to use the Model 331 in an actual experiment or application 3 12 Installation Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 4 OPERATION 4 0 GENERAL This chapter describes Model 331 Temperature Controller operation A definition of front panel controls is provided in Paragraph 4 1 Turning power on is described in Paragraph 4 2 Paragraphs 4 3 thru 4 20 describe operation of instrument features Instrument default settings are provided in Paragraph 4 21 Advanced operation is described in Chapter 5 Computer interface operation is detailed in Chapter 6 4 1 FRONT PANEL DESCRIPTION This paragraph provides a description of the front panel controls and indicators for the Model 331 4 1 1 Keypad Definitions An abbreviated description of each key is provided as follows A more detailed description of each function is provided in subsequent paragraphs See Figure 4 1 AutoTune Allows selection of closed loop tuning mode AutoTune PID PI P Manual PID or Zone for the currently selected loop Refer to Paragraph 4 9 Loop Toggles the front panel display and key functions between
192. ith Model 330 commands The 330 Emulation Mode only affects remote operation front panel operation of the Model 331 is not changed In 330 Emulation Mode curve locations are mapped to match Model 330 locations For example the DT 500 D Curve found at curve location 3 in the Model 331 is mapped to location 0 when in 330 mode This applies to the following remote commands ACUR ACUR BCUR BCUR The following Model 330 commands are not supported in 330 Emulation Mode CUID CURV CURV ECUR KCUR and SCAL 330 Emulation Mode Query EMUL term lt off on gt term n Refer to command for description Input Filter Parameter Command FILTER lt input gt lt off on gt lt points gt lt window gt term a n nn nn lt input gt Specifies input to configure A or B lt off on gt Specifies whether the filter function is 0 Off or 1 On lt points gt Specifies how many data points the filtering function uses Valid range 2 to 64 lt window gt Specifies what percent of full scale reading limits the filtering function Reading changes greater than this percentage reset the filter Valid range 1 to 10 FILTER B 1 10 2 term Filter input B data through 10 readings with 2 of full scale window Input Filter Parameter Query FILTER lt input gt term a lt input gt Specifies input to query A or B lt off on gt lt points gt lt window gt term n nn nn Refer to command for description Heater Outp
193. ities AAA 3 7 RELAYS and ANALOG OUTPUT Terminal Block 3 10 Model331 Front Panel ooooomrorai tara adria 4 1 Display RT ll 4 4 Display Format Definition des 4 5 Record ot ZONE SHIN iii ad olen ok 4 21 Deadbannd EXam ples iss 2 scssesensetess vac chang a ot ata dE 4 28 Relay Settings A eae ein ee en ee eee ee 4 30 SoftCal Temperature Ranges for Silicon Diode Sensors ooooncccnnocccnnnocccccononcnnnonnnonanonnncnnnnn cnn rnnn nn naar nro 5 8 SoftCal Temperature Ranges for Platinum Sensors oonoccccconocccononoccnononcnccnnnnnnnn nono nnnn no nn rr nano rra ran nr rra 5 9 GPIB Setting Configuration EE 6 6 DEV 12 Device Template Configuration o ooocccnnoncccnnnoccnononcnnnnnnon iiidid eded rare rr 6 6 Typical National Instruments GPIB Configuration from IBCONF EXE ooococococccccononcnonononcconnoncno nano ncnrnnnnnn 6 11 Model 3507 2SH Cable ASSEMDIY doocccccnoccconnococcnononononnnoncno nono eiin iddaa adadad ded nene rra 7 4 Model 3003 Heater Output Conditioner oooiococcnonocccononocanonononcnonon rn nonnno nn nr nono nnn nan n nr EnEn rr rra rre 7 4 Model RM 1 2 Rack Mount Kit iban 7 5 Model RM 2 D al Rack MountKit ico ged dees Seege edeEe ege Sebo 7 6 Power TEE 8 2 Sensor INPUT A and B Connector Details 8 3 HEATER OUTPUT Connector Detail dd 8 3 RELAYS and ANALOG OUTPUT Terminal Block 8 4 RS 232 Connector DetallS iii iaa 8 4 IEEE 488 Rear Panel Connector Details ooooocconnnccccnonoccccnnoncccnononcnonano cnn crono cn
194. itioner is a passive filter which reduces the already low noise present in the heater output of the Model 331 The Model 3003 connects between the heater output terminals on the rear panel of a controller and a resistive heater See Figure 7 2 Specifications are as follows Max Current 2A Max Voltage 60 V Attenuation 50 or 60 Hz line frequency 20 dB 100 Hz and above line frequency harmonics 40 dB Enclosure Size 144 mm wide x 72 mm long x 165 mm deep 5 7 x 2 8 x 6 5 inches Weight 1 6 kilograms 3 5 pounds The Model 3003 is a passive filter and requires no external power supply The High and Low terminals on the controller must be connected to the High and Low terminals marked From Controller on the Model 3003 The binding posts or a dual banana plug can be used to connect to the model 3003 Precautions must be taken to ensure the High and Low terminals are not reversed A diode in the Model 3003 shorts the heater output if the polarity of the terminals is reversed The High and Low terminals marked To Heater on the Model 3003 should be attached to a resistive heater used for temperature control The binding posts or a dual banana plug can be used to connect to the Model 3003 The ground terminals on the Model 3003 continue the shield if the heater cable is shielded FROM CONTROLLER CAUTION a THIS HI TERMINAL THE CONTROLLER S BI akeShore 3003 Heater Output Conditioner F 331 7 2 eps Figure 7 2 Model 3003 Heater Output Conditi
195. ke Shore Model 331 Temperature Controller User s Manual CAUTION Only JMP4 and JMP7 should be changed by the user Please consult with Lake Shore before changing any of the other jumpers pla Silkscreen Default Description esignator JMP1 RUN TEST RUN Used for diagnostic purposes only JMP2 RS 485 RS 232 RS 232 Serial Interface mode RS 485 is not supported JMP3 IEEE SHIELD Not Used Used for ground loop testing Set at factory to reflect configuration of Input A where 330 1 mA excitation current on Pin 3 of MES SE ene the connector and 340 Pin 3 connected to shield Refer to Paragraph 3 5 1 Set at factory to reflect configuration of Input A JMP5 DI RE TC where DI RE diode resistor and TC thermocouple Set at factory to reflect configuration of Input B JMP6 DI RE TC where DI RE diode resistor and TC thermocouple JMP7 330 340 330 Set at factory to reflect configuration of Input B where 330 1 mA excitation current on Pin 3 of the connector and 340 Pin 3 connected to shield Refer to Paragraph 3 5 1 8 8 ERROR MESSAGES The following are error message that may be displayed by the Model 331 during operation Message Description Di sabl eg Input is turned off Ho Curve Input has no curve DG Over Input is at or over full scale sensor units DG Under Input is at or under negative full scale sensor units T Over Input at or
196. kelvin to Celsius subtract 273 15 To convert Celsius to Fahrenheit multiply C by 1 8 then add 32 or F 1 8 x C 32 To convert Fahrenheit to Celsius subtract 32 from F then divide by 1 8 or C F 32 1 8 temperature coefficient measurement The measurement accuracy of an instrument is affected by changes in ambient temperature The error is specified as an amount of change usually in percent for every one degree change in ambient temperature tesla T The SI unit for magnetic flux density B 1 tesla 10 gauss thermal emf An electromotive force arising from a difference in temperature at two points along a circuit as in the Seebeck effect thermocouple A pair of dissimilar conductors so joined at two points that an electromotive force is developed by the thermoelectric effects when the junctions are at different temperatures tolerance The range between allowable maximum and minimum values torr Unit of pressure 1 torr 1 mm of mercury 1 atmosphere 760 torr two lead Measurement technique where one pair of leads is used for both excitation and measurement of a sensor This method will not reduce the effect of lead resistance on the measurement Underwriters Laboratories UL An independent laboratory that establishes standards for commercial and industrial products unit magnetic pole A pole with a strength such that when it is placed 1 cm away from a like pole the force between the two i
197. l PRODUCT DESCRIPTION Intelligently designed and well integrated for high performance and ease of use the Model 331 Temperature Controller is suitable for most cryogenic and many higher temperature measurement and control applications The Model 331 Temperature Controller combines the easy operation and unsurpassed reliability of the Model 330 with improved sensor input and interface flexibility including compatibility with negative temperature coefficient NTC resistance temperature detectors RTDs Backed by the Lake Shore tradition of excellence in cryogenic sensors and instrumentation the Model 331 Temperature Controller sets the standard for mid price range temperature control instruments The Model 331 Temperature Controller is available in two versions The Model 3318S is fully equipped for interface and control flexibility The Model 331E shares measurement and display capability with the Model 331S but does not include the IEEE 488 interface relays analog voltage output or a second control loop The choice of Model 331S or 331E must be specified by the purchaser at time of order and cannot be reconfigured in the field Sensor Inputs The Model 331 Temperature Controller is designed for high performance with sensors across the 1 4 K to over 1000 K temperature range and in difficult sensing conditions including magnetic fields The Model 331 Temperature Controller features two inputs with a high resolution 24 bit analog to digital
198. l P integral I and derivative D See Figure 2 3 Changing these variables for best control of a system is called tuning The PID equation in the Model 331 is Heater Output Po le dt D ei where the error e is defined as e Setpoint Feedback Reading Proportional is discussed in Paragraph 2 6 1 Integral is discussed in Paragraph 2 6 2 Derivative is discussed in Paragraph 2 6 3 Finally the manual heater output is discussed in Paragraph 2 6 4 Cooling System Design 2 9 2 6 1 2 6 2 2 6 3 2 6 4 Lake Shore Model 331 Temperature Controller User s Manual Proportional P The Proportional term also called gain must have a value greater than zero for the control loop to operate The value of the proportional term is multiplied by the error e which is defined as the difference between the setpoint and feedback temperatures to generate the proportional contribution to the output Output P Pe If proportional is acting alone with no integral there must always be an error or the output will go to zero A great deal must be known about the load sensor and controller to compute a proportional setting P Most often the proportional setting is determined by trial and error The proportional setting is part of the overall control loop gain and so are the heater range and cooling power The proportional setting will need to change if either of these change Integral I In the control loop the integral te
199. l 331S Only The Model 331S has one high and one low relay They are most commonly associated with the alarm feature The relays can also be placed in manual mode and controlled directly by the user from the front panel or over the computer interface Refer to Paragraph 4 15 and the RELAY command in Chapter 6 Normally Open N O Normally Closed N C and Common COM contacts are available for each relay All contacts including common are isolated from the measurement and chassis grounds of the instrument If a relay is inactive Off it will be in its normal state of open or closed When the relay is active On it will be in the opposite state Slides into slot at rear of Model 331 Use screwdriver to lock or unlock wires Terminal Block Connector Lake Shore P N 106 739 Insert wire into slot H 5 Description Pin Description Relay 1 Normally Closed NC 5 Relay 2 Common COM Relay 1 Common COM 6 Relay 2 Normally Open NO Relay 1 Normally Open NO 7 Loop2 Analog Voltage Output Hi Relay 2 Normally Closed NC 8 Loop2 Analog Voltage Output Lo Figure 3 5 RELAYS and ANALOG OUTPUT Terminal Block hon 3 10 Installation Lake Shore Model 331 Temperature Controller User s Manual Relays Continued Relay connections are available in positions 1 thru 6 of the detachable RELAY and ANALOG OUTPUT Terminal Block See Figure 3 5 The terminal block
200. l methods of tuning Open Loop Control Open loop control is less complicated than closed loop control but is also less powerful Open loop control mode allows the user to directly set the manual heater power output for Loop 1 control output for Loop 2 using only the Manual Heater Power MHP parameter During Open Loop control only the heater range and MHP Output parameters are active the setpoint control sensor and PID parameters are ignored This type of control guarantees constant power to the load but it does not actively control temperature Any change in the characteristics of the load will cause a change in temperature Closed loop control is available for both loops and no tuning is required Tuning Modes The Model 331 offers three tuning modes or ways to set the necessary P and D parameters for closed loop control MHP output is active during closed loop control and must be set to zero if not wanted Heater range must also be considered as part of tuning when using control Loop 1 Manual PID Tuning Manual tuning is the most basic tuning method The user manually enters parameter values for P and D as well as heater range using their knowledge of the cooling system and some trial and error Refer to Paragraphs 2 7 and 4 8 for guidelines Manual tuning can be used in any situation within the control capabilities of the instrument AutoTune The Model 331 automates the tuning process with an AutoTune algorithm This algorithm measu
201. latching mode where alarms automatically reset when the activation condition ends to perform simple on off control functions Relay assignments are configurable so that one relay may be assigned to each input or both assigned to a single input for high low control The analog voltage output on the Model 331S can be configured to send a voltage proportional to temperature to a strip chart recorder or data acquisition system The user may select the scale and data sent to the output including temperature sensor units or linear equation results Under manual control the analog voltage output can also serve as a voltage source for any other application Factory Configured Inputs Sensor inputs for both versions of the Model 331 are factory configured and compatible with either Diode RTD or Thermocouple sensors The choice of 2 Diode RTD inputs 1 Diode RTD input and 1 Thermocouple input or 2 Thermocouple inputs must be specified by the purchaser at time of order The configuration cannot be changed in the field The software selects the appropriate excitation current and signal gain levels when the sensor type is entered via the instrument front panel The Diode RTD input configuration is compatible with most diode and negative and positive temperature coefficient RTDs Current reversal eliminates thermal EMF voltage errors for resistor sensors The Thermocouple input configuration is compatible only with thermocouple sensors Room temperature co
202. lation is preferred and twisted wire should be used to reduce the effect of RF noise if it is present The wire used on the room temperature side of the vacuum boundary is nat critical so copper cable is normally used j To Room Temperature Vacuum Shroud Refrigerator Expander Vacuum Space Radiation Shield Dental Floss Tie Down Thermal Anchor or Bobbin Cryogenic Tape Refrigerator Second Stage Thermal Anchor Cryogenic Wire Bobbin small diameter large AWG Cold Stage and Sample Holder Sensor Drawing Heater Not To Scale g z fairing not shown Optical Window y If Required P 331 2 2 bmp Figure 2 2 Typical Sensor Installation In A Mechanical Refrigerator 2 6 Cooling System Design 2 4 2 4 1 Lake Shore Model 331 Temperature Controller User s Manual Lead Soldering When additional wire is soldered to short sensor leads care must be taken not to overheat the sensor A heat sink such as a metal wire clamp or alligator clip will heat sink the leads and protect the sensor Leads should be tinned before bonding to reduce the time that heat is applied to the sensor lead Solder flux should be cleaned after soldering to prevent corrosion Heat Sinking Leads Sensor leads can be a significant source of error if they are not properly heat sinked Heat will transfer down even small leads and alter the sensor reading The goal of heat sinking is to cool the leads to a temperature as clos
203. le gt term a n n tnnnnnn tnnnnnn nnnnnn n lt input gt Specifies which input to configure A or B lt off on gt Determines whether the instrument checks the alarm for this input where 0 off and 1 on lt source gt Specifies input data to check Valid entries 1 kelvin 2 Celsius 3 sensor units 4 linear data lt high value gt Sets the value the source is checked against to activate the high alarm lt low value gt Sets the value the source is checked against to activate low alarm lt deadband gt Sets the value that the source must change outside of an alarm condition to deactivate an unlatched alarm lt latch enable gt Specifies a latched alarm remains active after alarm condition correction where 0 off no latch and 1 on Configures the alarm parameters for an input ALARM A 0 term Turns off alarm checking for Input A ALARM B 1 1 270 0 0 0 1 term Turns on alarm checking for input B activates high alarm if kelvin reading is over 270 and latches the alarm when kelvin reading falls below 270 Input Alarm Parameter Query ALARM lt input gt term a lt input gt AorB lt off on gt lt source gt lt high value gt lt low value gt lt deadband gt lt latch enable gt term n n tznnnnnn nnnnnn tnnnnnn n Refer to command for description ALARMST Input Alarm Status Query Input ALARMST lt input gt term Format a lt input gt AorB Returned lt high state gt lt low
204. ltiple device systems The connectors are secured in the receptacles by two captive locking screws with metric threads The total length of cable allowed in a system is 2 meters for each device on the bus or 20 meters maximum The Model 331 can drive a bus of up to 10 devices A connector extender is required to use the IEEE 488 Interface and Relay Terminal Block at the same time Figure 8 6 shows the IEEE 488 Interface connector pin location and signal names as viewed from the Model 331 rear panel IEEE 488 INTERFACE SH1 AH1 T5 L4 SR1 RL1 PPO DC1 DTO CO E1 gt 12 11 10 9 8 7 6 5 4 3 2 1 2 23 2 21 20 9 18 17 16 15 14 13 PIN SYMBOL DESCRIPTION Data Input Output Line 1 Data Input Output Line 2 Data Input Output Line 3 Data Input Output Line 4 End Or Identify Data Valid Not Ready For Data Not Data Accepted Interface Clear Service Request Attention Cable Shield Data Input Output Line 5 Data Input Output Line 6 Data Input Output Line 7 Data Input Output Line 8 Remote Enable Ground Wire Twisted pair with DAV Ground Wire Twisted pair with NRFD Ground Wire Twisted pair with NDAC Ground Wire Twisted pair with IFC Ground Wire Twisted pair with SRQ Ground Wire Twisted pair with ATN Logic Ground C 331 8 6 eps OO Oo JO om P Gobh Figure 8 6 IEEE 488 Rear Panel Connector Details 8 6 Service Lake Shore Model 331 Temperature Controller User s Manual 8
205. maximum rated value of the variable being measured dynamic data exchange DDE A method of interprocess communication which passes data between processes and synchronized events DDE uses shared memory to exchange data between applications and a protocol to synchronize the passing of data dynamic link library DLL A module that contains code data and Windows resources that multiple Windows programs can access electromagnet A device in which a magnetic field is generated as the result of electrical current passing through a helical conducting coil It can be configured as an iron free solenoid in which the field is produced along the axis of the coil or an iron cored structure in which the field is produced in an air gap between pole faces The coil can be water cooled copper or aluminum or superconductive electrostatic discharge ESD A transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field error Any discrepancy between a computed observed or measured quantity and the true specified or theoretically correct value or condition excitation Either an AC or DC input to a sensor used to produce an output signal Common excitations include constant current constant voltage or constant power Fahrenheit F Scale A temperature scale that registers the freezing point of water as 32 F and the boiling point as 212 F under normal atmospher
206. mbol are omitted from this unit See Temperature Scale for conversions A 4 Glossary of Terminology Lake Shore Model 331 Temperature Controller User s Manual Kelvin Scale The Kelvin Thermodynamic Temperature Scale is the basis for all international scales including the ITS 90 It is fixed at two points the absolute zero of temperature 0 K and the triple point of water 273 16 K the equilibrium temperature that pure water reaches in the presence of ice and its own vapor line regulation The maximum steady state amount that the output voltage or current changes as result of a specified change in input line voltage usually for a step change between 105 125 or 210 250 volts unless otherwise specified line voltage The RMS voltage of the primary power source to an instrument liquid helium LHe Used for low temperature and superconductivity research minimum purity 99 998 Boiling point at 1 atm 4 2 K Latent heat of vaporization 2 6 kilojoules per liter Liquid density 0 125 kilograms per liter EPA Hazard Categories Immediate Acute Health and Sudden Release of Pressure Hazards DOT Name Helium Refrigerated Liquid DOT Label Nonflammable Gas DOT Class Nonflammable Gas DOT ID No UN 1963 liquid nitrogen LN Also used for low temperature and superconductivity research and for its refrigeration properties such as in freezing tissue cultures minimum purity 99 998 O2 8 ppm max Boiling point at 1 atm 77 4 K La
207. means the output current is within specification when the compliance voltage is between zero and the specified voltage curve A set of data that defines the temperature response of a temperature sensor It is used to convert the signal from the sensor to temperature Curve 10 The voltage vs temperature characteristic followed by all DT 400 Series Silicon Diode Temperature Sensors A 2 Glossary of Terminology Lake Shore Model 331 Temperature Controller User s Manual decibels dB A unit for describing the ratio of two powers or intensities or the ratio of a power to a reference power SS to one tenth bel if P4 and P2 are two amounts of power the first is said to be n decibels greater where 10 logio P1 P2 sane An incremental value in the temperature scale i e there are 100 degrees between the ice point and the boiling point of water in the Celsius scale and 180 degrees between the same two points in the Fahrenheit scale demagnetization when a sample is exposed to an applied field Ha poles are induced on the surface of the sample Some of the returned flux from these poles is inside of the sample This returned flux tends to decrease the net magnetic field strength internal to the sample yielding a true internal field Hint given by Hint Ha DM where M is the volume magnetization and D is the demagnetization factor D is dependent on the sample geometry and orientation with respect to the field deviation Je differen
208. meters The curve name cannot be changed from the front panel Curve names can only be Name entered over the computer interface up to 15 characters The default curve name is User xx where xx is the curve number Identify specific sensors with serial numbers of up to 10 characters The serial Serial number field accepts both numbers and letters but the instrument front panel Num enters only numbers To enter both numbers and letters enter curves over computer interface The default is blank The instrument must know the data format of the curve breakpoints Different sensor types use different data formats The sensor inputs require one of the formats below The range and resolution specified are not always available at the same time Practical range and resolution depend on the sensor type Curve Sensor Units Sensor Units Format Format Description Full Scale Range Maximum Resolution VIR Volts vs Kelvin 10 V 0 00001 V Q K Resistance vs Kelvin 10 K Q 0 001 Q log Q K log Resistance vs Kelvin 4 log Q 0 00001 log Q mV K mV vs Kelvin 100 mV 0 0001 mV ep A setpoint temperature limit can be included with every curve When controlling in Limit temperature the setpoint cannot exceed the limit entered with the curve for the control sensor The default is 375 K Set to 9999 K if no limit is required The instrument derives the temperature coefficient from the first two breakpoints Coeff
209. ming substitutes for hardware handshaking User programs must take full responsibility for flow control and timing as described in Paragraph 6 2 5 6 14 Remote Operation 6 2 3 6 2 4 Lake Shore Model 331 Temperature Controller User s Manual Character Format A character is the smallest piece of information that can be transmitted by the interface Each character is 10 bits long and contains data bits bits for character timing and an error detection bit The instrument uses 7 bits for data in the ASCII format One start bit and one stop bit are necessary to synchronize consecutive characters Parity is a method of error detection One parity bit configured for odd parity is included in each character ASCII letter and number characters are used most often as character data Punctuation characters are used as delimiters to separate different commands or pieces of data Two special ASCII characters carriage return CR ODH and line feed LF OAH are used to indicate the end of a message string Table 6 4 Serial Interface Specifications Connector Type 9 pin D style connector plug Connector Wiring DTE Voltage Levels ElA RS 232C Specified Transmission Distance 50 feet maximum Timing Format Asynchronous Transmission Mode Half Duplex Baud Rate 300 1200 9600 Handshake Software timing Character Bits 1 Start 7 Data 1 Parity 1 Stop Parity Odd Terminators CR ODH LF OAH Command Rate 20 commands per second maxi
210. mory reset 4 Check all cable connections Intermittent Lockups 1 Check cable connections and length 2 Increase delay between all commands to 100 ms to make sure instrument is not being over loaded Remote Operation 6 21 Lake Shore Model 331 Temperature Controller User s Manual 6 3 COMMAND SUMMARY This paragraph provides a listing of the IEEE 488 and Serial Interface Commands A summary of all the commands is provided in Table 6 8 All the commands are detailed in Paragraph 6 3 1 which is presented in alphabetical order Sample Command Format Command name Brief description of command Form of the command input Input Curve Number Command Syntax of user parameter input INCRV lt input gt lt curve number gt term a nn See Key below lt input gt Specify input A or B Definition of first parameter lt curve number gt Specify input curve O none 1 20 std curves Definition of second parameter 21 41 user curves Commands may additionally include Remarks and Examples Sample Query Format Query name Brief description of query Form of the query input Input Curve Number Query Syntax of user parameter input Format Pon lt input gt term See Key below lt input gt Specify input A or B Returned lt curve number gt term Format nn Definition of returned parameter Syntax of returned parameter The initial Format definition is omitted for queries that do not require parameter input Key Beg
211. mpensation is included for any type of thermocouple in use Appropriate temperature response curves for many types of thermocouples are included Temperature response curves may be entered as user curves for other thermocouples Autotuning The Model 331S and 331E Autotuning feature computerizes the tuning process With its own measurements of system characteristics and based on characteristics of typical cryogenic systems the Autotuning function computes proportional integral and derivative setting values On the Model 331S the Autotune function tunes one control loop at a time Because setting an inappropriate heating range is potentially dangerous to some loads the Model 331S and 331E Autotuning feature does not attempt to automate that step of the tuning process SoftCal The Lake Shore SoftCal algorithm for silicon diode and platinum RTD sensors is a good solution for applications that need more accuracy than a standard sensor curve but not traditional calibration SoftCal uses the predictability of a standard curve to improve the accuracy of an individual sensor around a few known temperature reference points Both versions of the Model 331 can generate SoftCal curves Configurable Display Both versions of the Model 331 include a bright vacuum fluorescent display that simultaneously displays up to four readings Display data includes input and source annunciators for each reading All four display locations can be configured by the u
212. mple ensor 1 4H calibration 1 4H calibration 14J calibration 1 4G calibration 0 3E calibration LSCI Curve 10 Requires calibrated DIN 43760 Scaled from Requires calibrated Standard Sensor Curve sensor DIN 43760 sensor 33 6 mViK at4 2K 210 mVIKat4 2K 0 19 Q K at 30 K 1 9 QIK at 30 K 80 Q K at 4 2 K eer Soe 1 9mVIKat77K 1 25mV Kat77K 0 42 0 Kat77 K 4 2 QIK at 77 K 4 QIK at 20 K ypical Sensor sensitivity 2 4 mV K at300K 2 85 mV K at 300K 0 39 Q K at 300 K 3 9 QIK at 300 K 1 06 Q K at 40 K 2 2 mVIK at475K 3 15 mV K at475K 0 36 Q K at 800 K 3 6 Q K at 800 K Measurement Resolution Sensor Units 10 pV 20 uV 2 mQ 20 mQ 40 MQ Temperature Equivalence 0 3 mK at 4 2 K 0 1 mK at 4 2 K 10 6 mK at 30 K 11 mK at 30 K lt 1 mK at 4 2 K 55mKat77K 16 0 mK at 77 K 4 8 mK at 77 K 4 8 mK at 77 K 10 mK at 20 K 4 2 mK at 300 K 7 1 mK at 300 K 5 2 mK at 300 K 5 2 mK at 300 K 38 mK at 40 K 45 mK at 475 K 6 3 mK at 475 K 5 6 mK at 800 K 5 6 mK at 800 K Electronic Accuracy Sensor Units 80 uV 0 005 80 uV 0 01 0 004 Q 0 01 0 04 Q 0 02 0 10 Q 0 04 of reading of reading of reading of reading of reading Temperature Equivalence 5 mK at 4 2 K 3 mK at 4 2 K 23 mK at 30 K 25 mK at 30 K 8 1 mK at 4 2 K 70 mK at 77 K 180 mK at 77 K 14 mK at 77 K 19 mK at 77 K 134 mK at 20 K 45 mK at 300 K 60 mK at 300 K 39 mK at 300 K 67 mK at 300 K 491 mK at 40 K 40 mK at 475 K 38 mK at 475 K 95 mK at 800 K 172 mK at 800 K 26 mK at 4 2
213. mum Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command strings can be chained together in one communication but they must be separated by a semi colon Only one query is permitted per communication but it can be chained to the end of a command The total communication string must not exceed 64 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting The format is lt command mnemonic gt lt space gt lt parameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 6 3 Terminators must be sent with every message string A query string is issued by the computer and instructs the instrument to send a response The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in Paragraph 6 3 Terminators must be sent with every message string The computer should expect a response very soon af
214. n Lake Shore Model 331 Temperature Controller User s Manual 4 21 DEFAULT VALUES It is sometimes necessary to reset instrument parameter values or clear out the contents of curve memory Both are all stored in nonvolatile memory called NOVRAM but they can be cleared individually Instrument calibration is not affected except for Room Temperature Calibration which should be redone after parameters are set to default values or any time the thermocouple curve is changed To reset the Model 331 parameters to factory default values press and hold the Escape key until the screen shown below appears Use the A or Y key to select Yes or No to reset the NOVRAM Select Yes to reset all Model 331 parameters to the defaults listed in Table 4 5 Press the Enter key The second screen appears as follows CH Ee Use the A or Y key to select Yes or No to clear the user curves in locations 21 41 stored in the Model 331 Standard curves in locations 1 20 are unaffected Press the Enter key The instrument performs the operation then returns to the normal display Operation 4 37 Lake Shore Model 331 Temperature Controller User s Manual Table 4 5 Default Values Alarm and Relay Nee Off Alarm Audible Off Relay diiniita Off Relay 2ce Off Analog Output Analog Output Off Control Setup Control Input Input A SP Units Temp K Control Mode Closed Power Up
215. n lt curve gt Specifies which curve to query 1 41 lt index gt Specifies the points index in the curve 1 200 lt units value gt lt temp value gt term nnnnnnn tnnnnnnn Refer to command for description Returns a standard or user curve data point Remote Operation 6 29 Lake Shore Model 331 Temperature Controller User s Manual CSET Control Loop Parameter Command Input CSET lt loop gt lt input gt lt units gt lt powerup enable gt lt current power gt term Format n a n n n lt loop gt Specifies which loop to configure 1 or 2 lt input gt Specifies which input to control from A or B lt units gt Specifies setpoint units Valid entries 1 kelvin 2 Celsius 3 sensor units lt powerup enable gt Specifies whether the control loop is on or off after power up where 0 powerup enable off and 1 powerup enable on lt current power gt Specifies whether the heater output displays in current or power Valid entries 1 current or 2 power Example CSET 1 A 1 1 term Control Loop 1 controls off of Input A with setpoint in kelvin CSET Control Loop Parameter Query Input CSET lt loop gt term Format n lt loop gt Specifies which loop to query 1 or 2 Returned lt input gt lt units gt lt powerup enable gt lt current power gt term Format a n n n Refer to command for description DFLT Factory Defaults Command Input DFLT 99 term Remarks Sets all configuration val
216. n nan nn nnnnn nr rrnnn rare 8 6 Location of Internal Component iii bano 8 9 Temperature Scale Comparison dia B 1 Typical Cryogenic Storage Dewar nn nr nono nn nr non nr rra rre r nn adrasdan kiei r rear nn rra nn nnniins C 1 Table of Contents Lake Shore Model 331 Temperature Controller User s Manual LIST OF TABLES Table No Title Page 1 1 Temperature Range of Typical Lake Shore Sensors eecceeesceeeeeeeeeeeeneeeeeeeeeeeseaeeeeeeaeeeseeeeeeesenneeeeeaes 1 4 1 2 Model 331 Sensor Input Performance Chart 1 5 4 1 Sensor Input KEE 4 7 4 2 Sensor CURVES ii A A A A Mca ee 4 11 4 3 Comparison of Control Loops 1 and 2 4 13 4 4 Linear Equation Configurar tc 4 5 Default Values ts 5 1 Curve Header Parameters unan ticas it 5 2 Recommended Curve Parameters 6 1 IEEE 488 Interface Program Control Properties A 6 8 6 2 Visual Basic IEEE 488 Interface Program 6 9 6 3 Quick Basic IEEE 488 Interface Program 6 12 6 4 Serial Interface Specifications ccoo id oia 6 15 6 5 Serial Interface Program Control Properties A 6 18 6 6 Visual Basic Serial Interface Program 6 19 6 7 Quick Basic Serial Interface Program ocio inet ites 6 20 6 8 Command Summary EE 6 23 8 1 Calibration Table for Diode RANGES s 2 0 2 2 ecveuepcvsssces ues cetenewetanathescubesstecenaes sadekestobeeeuteesebeteeeeoscbcnivenstes 8 12 8 2 Calibration Table for Resistive Ranges conan no tidien tekade rr nn nn rn nnn anna rre 8 14 8 3 Calibration Table f
217. nalog output can be controlled manually by the user for any application that requires a programmable voltage source or as mentioned above as Control Loop 2 Refer to Paragraph 4 16 and the ANALOG command in Chapter 6 The analog output is a variable DC voltage source that can vary from 10 V to 10 V The resolution of the analog output is 0 3 mV or 0 003 of full scale The output can source up to 100 mA of current providing a maximum of 1 W of power It can drive a resistive load of no less than 100 Q The output is short protected so the instrument is not harmed if the heater resistance is too small It is not recommended because the additional load on instrument power supplies causes noise on internal circuits The output for the analog outputs is available from positions 7 and 8 of the detachable RELAY and ANALOG OUTPUT Terminal Block See Figure 3 5 The terminal marked positive is the output voltage terminal the terminal marked negative is the ground and is attached to chassis ground inside the instrument It is not recommended to attach the analog output ground to a ground outside the instrument The output should be read by an instrument with an isolated or differential input wherever possible Connecting to an external ground can cause noise in the analog output voltage or the sensor input measurement If this cannot be avoided try to keep the chassis of the two instruments at the same potential with a ground strap RELAYS Mode
218. national Electrotechnical Commission IEC safety standards Introduction 1 9 Lake Shore Model 331 Temperature Controller User s Manual Safety Summary Continued 1 5 Ventilation The instrument has ventilation holes in its side covers Do not block these holes when the instrument is operating Do Not Operate In An Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away From Live Circuits Operating personnel must not remove instrument covers Refer component replacement and internal adjustments to qualified maintenance personnel Do not replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them Do Not Substitute Parts Or Modify Instrument Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to an authorized Lake Shore Cryotronics Inc representative for service and repair to ensure that safety features are maintained Cleaning Do not submerge instrument Clean only with a damp cloth and mild detergent Exterior only SAFETY SYMBOLS Direct current power line Equipment protected throughout by double insulation or reinforced insulation equivalent to Class II of IEC 536 see Annex H Caution High voltages danger of electric sho
219. nd the setpoint the integral setting is too high and should be reduced by one half If the temperature is stable but never reaches the setpoint the integral setting is too low and should be doubled To verify the integral setting make a few small 2 to 5 degree changes in setpoint and watch the load temperature react Trial and error can help improve the integral setting by optimizing for experimental needs Faster integrals for example get to the setpoint more quickly at the expense of greater overshoot In most systems setpoint changes that raise the temperature act differently than changes that lower the temperature If it was not possible to measure the oscillation period of the load during proportional setting start with an integral setting of 20 If the load becomes unstable reduce the setting by half If the load is stable make a series of small two to five degree changes in the setpoint and watch the load react Continue to increase the integral setting until the desired response is achieved Tuning Derivative If an experiment requires frequent changes in setpoint or data taking between changes in the setpoint derivative should be considered See Figure 2 3 e A derivative setting of zero off is recommended when the control system is seldom changed and data is taken when the load is at steady state The derivative setting is entered into the Model 331 as a percentage of the integral time constant The setting range is 0 200
220. no strict convention exists for the use of remanent induction and remanence and in some contexts the two terms may be used interchangeably remanent induction The remaining magnetic induction in a magnetic material after an applied field is reduced to zero Also see remanence repeatability The closeness of agreement among repeated measurements of the same variable under the same conditions resistance temperature detector RTD Resistive sensors whose electrical resistance is a known function of the temperature made of e g carbon glass germanium platinum or rhodium iron resolution The degree to which nearly equal values of a quantity can be discriminated display resolution The resolution of the physical display of an instrument This is not always the same as the measurement resolution of the instrument Decimal display resolution specified as n digits has 10 possible display values A resolution of n and one half digits has 2 x 10 possible values measurement resolution The ability of an instrument to resolve a measured quantity For digital instrumentation this is often defined by the analog to digital converter being used A n bit converter can resolve one part in 2 The smallest signal change that can be measured is the full scale input divided by 2 for any given range Resolution should not be confused with accuracy RhFe Rhodium iron Rhodium alloyed with less than one atomic percent iron is used to make the L
221. not display for the system Alarm annunciator to indicate input alarm status The beeper inside the instrument can also be programmed to sound if any alarms activate The two relays on a 331S can also be tied to alarm functions as described below Latching Alarms Often used to detect faults in a system or experiment that require operator intervention The alarm state remains visible to the operator for diagnostics even if the alarm condition is removed Relays often signal remote monitors or for added safety take critical equipment off line Pressing the Alarm key clears latched alarms Non Latching Alarms Often tied to relay operation to control part of a system or experiment The alarm state follows the reading value The dead band parameter can prevent relays from turning on and off repeatedly when the sensor input reading is near an alarm setpoint Example If the high alarm setpoint 100 K and the dead band 1 K the high alarm triggers when sensor input temperature increases to 100 K and it will not deactivate until temperature drops to 99 K Figure 4 5 illustrates the interaction between alarm setpoint and dead band In Figure 4 5 with the high alarm setpoint at 100 K and the dead band at 5 K the high alarm triggers when sensor input temperature increases to 100 K and it will not deactivate until temperature drops to 95 K In addition the same 5 K dead band is applied to the low alarm setpoint as well ES High Alarm Deactivated
222. nox RTD CX 1030 AA or SD 2 325 K High Temperature Cernox RTD CX 1030 SD HT 2 420K Rox Ruthenium Oxide RTD RX 102A 2 40K Rox Ruthenium Oxide RTD RX 202A 3 40K Thermox Thermistor TX 1 4 GB 110 325 K Thermocouples Chromel versus AuFe 0 07 Model 9006 002 1 4 610K Type E Model 9006 004 3 2 930 K Type K Model 9006 006 3 2 1500 K Type T Model 9006 008 3 2 670 K Sensors sold separately Single excitation current may limit the low temperature range of NTC resistors Introduction Lake Shore Model 331 Temperature Controller User s Manual Sensor Selection Guide Continued Rox RTD thick film sensors are useful in low temperature applications in magnetic fields with a very low incidence of magnetic field errors Each model adheres to a single resistance versus temperature curve The Rox Models RX 102A and RX 202A are useful to temperatures as low as 50 mK with accuracy to within 5 mK at 50 mK the RX 202A also offers an upper temperature range to 300 K Thermocouples offer uniform sensitivity over a wide temperature range and measure the highest temperatures possible with the Model 331 While many types are inexpensive and standard curves are available thermocouples are less accurate than other sensors Repeatability is highly dependent upon installation Table 1 2 Model 331 Sensor Input Performance Chart E le LSCIS DT 470 CO 13 with TG 120 SD with PT 103 with PT 1001 with RX 102A AA with a
223. nt WHILE N lt TIMEOUT AND INSTR RS TERMS 0 Wait for response INS INPUTS LOC 1 1 Get one character at a time IF INS THEN N N 1 ELSE N 0 Add 1 to timeout if no chr RS RSS INS Add next chr to string WEND Get chrs until terminators IF RS lt gt THEN See if return string is empty RSS MIDS RS 1 INSTR RS TERMS 1 Strip off terminators PRINT RESPONSE RS Print response to query ELSE PRINT NO RESPONSE No response to query END IF END IF Get next command GOTO LOOP1 6 20 Remote Operation 6 2 7 3 Lake Shore Model 331 Temperature Controller User s Manual Program Operation Once either example program is running try the following commands and observe the response of the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND IDN Identification query Instrument will return a string identifying itself RESPONSE LSCI MODEL331S8 123456 020399 term ENTER COMMAND KRDG Temperature reading in kelvin query Instrument will return a string with the present temperature reading RESPONSE 273 15 term ENTER COMMAND RANGE 0 Heater range command Instrument will turn off the heater No response will be sent ENTER COMMAND RANGE Heater range query Instrument will return a string with the present heater range setting RESPONSE 0 term
224. nt Press the Enter key The audible parameter determines whether the internal beeper will sound when an alarm is active This is a global parameter so it is set once for all alarms After specifying either Alarm Setpoint On or Dead Band next is the Alarm Audible screen Use the A or Y key to toggle between Audible Alarm On or Off For this example select Audible Alarm On Press the Enter key Operation 4 29 Lake Shore Model 331 Temperature Controller User s Manual 4 15 2 Relays 331S Only There are two relays on the Model 331S numbered 1 and 2 They are most commonly thought of as alarm relays but may be manually controlled also Relay assignments are configurable as shown in Figure 4 6 Two relays can be used with one sensor input for independent high and low operation When using relays with alarm operation set up alarms first The relays are rated for 30 VDC and 5 A Their terminals are in the detachable terminal block on the Model 331S rear panel Relay Settings Relay 1 Relay 2 Off On A Alarm B Alarm Off On A Alarm B Alarm Manual Off Manual On Manual Off Manual On Follows Follows ema state Ave state ene cae cade Input A Input B l Both Low High Both Low High Alarms Alarm Alarm Alarms Alarm Alarm Off Manual Off Relay
225. nt in the curve press the Enter key then the Escape key You will return to the normal display To add a new breakpoint to an existing curve go to the end of the curve data and enter the new sensor reading and temperature Press the Enter key then the Escape key The new point is automatically put into its proper place in breakpoint sequence NOTE Typing over an existing reading or temperature will replace that value when you press the Enter key To delete a breakpoint go to point and enter all zeros for both the sensor reading and temperature Press the Enter key then the Escape key When curve entry is complete the user must assign the new curve to an input The Model 331 does not automatically assign the new curve to either input Thermocouple Curve Considerations The following are things to consider when generating thermocouple curves Users may enter temperature response curves for all types of thermocouples Enter curve data in mV K format with thermocouple voltage in millivolts and temperature in Kelvin e The curve must be normalized to 0 mV at 273 15K 0 C Thermocouple voltages in millivolts are positive when temperature is above that point and negative when temperature is below that point e To convert curves published in Celsius to Kelvin add 273 15 to the temperature in Celsius e The temperature range for some thermocouple types may extend below 1 K or above 1000 K s The input voltage of the 331 is limited to
226. nt load damage load The setpoint limit in the temperature response curve sets maximum safe temperature in kelvin for the sensor package It can be verified by using the Curve Entry key The setpoint is limited to a value less than or equal to the limit If the setpoint value changes from the number entered when Enter is pressed it is likely the setpoint exceeds the above limit or is inappropriate for the sensor type Once control setup parameters are configured Paragraph 4 7 and the active control loop is selected Paragraph 4 6 1 the desired temperature setpoint is entered by pressing the Setpoint key The setpoint is entered using the numeric keypad which includes the numbers 0 9 and decimal point Press the Enter key to accept the new setpoint or press the Escape key to cancel If the display format is configured to show the setpoint Paragraph 4 3 you will see something resembling the following for a normal display 4 22 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 12 RAMP The Model 331 generates a smooth setpoint ramp when the setpoint units are expressed in temperature The user can set a ramp rate in degrees per minute with a range of O to 100 and a resolution of 0 1 Once the ramp feature is turned on its action is initiated by a setpoint change When a new setpoint is entered the instrument changes the setpoint temperature from the old value to the new valu
227. number increases There should not be any breakpoint locations left blank in the middle of a curve The search routine in the Model 331 interprets a blank breakpoint as the end of the curve FRONT PANEL CURVE ENTRY OPERATIONS There are three operations associated with front panel curve entry Edit curve Copy curve Erase curve as detailed below Edit Edit allows the user to see any curve and enter or edit a curve at Refer to Curve any user curve location Standard curves cannot be changed Paragraph 5 2 1 Erase Erase allows the user to delete a curve from any user curve Refer to Curve location Standard curves cannot be erased Paragraph 5 2 2 curve locations SoftCal Allows creation of a new temperature curve from a standard Refer to curve and known data points entered by the user Paragraph 5 3 Co Copy allows the user to copy a curve from any location to any Refer to pane user curve location Curves cannot be copied into standard Paragraph 5 2 3 To begin a curve operation press the Curve Entry key and the above selections appear Press the Next Setting key until the desired operation is highlighted and press the Enter key A curve screen appears with the curve number highlighted Change to the desired curve number with the up or down arrow key then press the Enter key to begin the desired curve operation 5 2 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual Table 5 1 Curve Header Para
228. o Display C Celsius None No Display Display Location 1 Sensor V mV or Q Linear e Min lt Input Reading Source Max gt H 295 22K E 295 ZZE a 2950 BAK He OFF Display Location 3 Source Display Location 4 Source Input A F Same choices as Input A Same choices as Input B Display Location 1 Input B Display Location 1 Setpoint Units Heater Out Heater Output Loop 1 None No Display K Kelvin None No Display 0 Off Heater Off C Celsius XX Low 0 5 W Heater Range Sensor V mV or Q XX Med 5 W Heater Range XX High 50 W Heater Range Or Setpoint Units and Heater Out Current or Power settings are Heater Output Loop 2 under the Control Setup key All remaining selections in this Off L2 Heater Off illustration are made under the Display Format key XX L2 Heater On 1 W C331 4 2 eps Figure 4 2 Display Definition TURNING POWER ON After verifying line voltage Paragraph 3 4 plug the instrument end of the line cord included with the connector kit into the power and fuse assembly receptacle on the instrument rear Plug the opposite end of the line cord into a properly grounded three prong receptacle Place the power switch located next to the line cord receptacle to the On I position The instrument initiates the following power up sequence the instrument alarm sounds once the display shows the following startup message ENE emp Controlle
229. oad or clamped to a flat surface Heat sinking for good thermal contact is again important Foil heaters are thin layers of resistive material adhered to or screened on to electrically insulating sheets There are a variety of shapes and sizes The proper size heater can evenly heat a flat surface or around a round load The entire active area should be in good thermal contact with the load not only for maximum heating effect but to keep spots in the heater from over heating and burning out Heater Wiring When wiring inside a vacuum shroud we recommend using 30 AWG copper wire for heater leads Too much heat can leak in when larger wire is used Heat sinking similar to that used for the sensor leads should be included so that any heat leaking in does not warm the load when the heater is not running The lead wires should be twisted to minimize noise coupling between the heater and other leads in the system When wiring outside the vacuum shroud larger gage copper cable can be used and twisting is still recommended CONSIDERATION FOR GOOD CONTROL Most of the techniques discussed above to improve cryogenic temperature accuracy apply to control as well There is an obvious exception in sensor location A compromise is suggested below in Paragraph 2 5 3 Two Sensor Approach Thermal Conductivity Good thermal conductivity is important in any part of a cryogenic system that is intended to be at the same temperature Most systems begin wi
230. og for details A list of accessories available for the Model 331 is as follows Model Description Of Accessories Heater Output Connector Dual banana jack for Heater Output Sensor Input Mating Connector 6 pin DIN plug for Diode Resistor Input Terminal Block Mating Connector 8 pin terminal block for Relays and Analog Output Detachable 120 VAC Line Cord EN Heater Output Conditioner The heater output conditioner is a passive filter which further reduces the already low heater output noise of the Model 331 For details refer to Paragraph 7 4 and see Figure 7 2 3507 2SH Sensor Heater Cable Assembly Cable assembly for 2 diode resistor sensors and Loop 1 heater Approximately 3 meters 10 feet long See Figure 7 1 IEEE 488 Cable Kit One meter 3 feet long IEEE 488 GPIB computer interface cable Includes extender required to use both IEEE cable and relay terminal block simultaneously Stycast Epoxy 2850 FT Catalyst 9 20 packets 2 grams each Stycast is a common highly versatile nonconductive epoxy resin system for cryogenic use The primary use for Stycast is for vacuum feedthroughs or permanent thermal anchors Stycast is an alternative to Apiezon N Grease when permanent sensor mountings are desired Indium Solder Disks Quantity 10 Indium is a semi precious non ferrous metal softer than lead and extremely malleable and ductile It stays soft and workable down to cryogenic temperatures Indium can be used to cr
231. one Settings Operation 4 21 Lake Shore Model 331 Temperature Controller User s Manual 4 11 SETPOINT The control setpoint is the desired load temperature expressed in temperature or sensor units Use sensor units if no temperature response curve is selected for the sensor input used as the control channel The control setpoint has its own units parameter Set with the Control Setup key in Paragraph 4 7 Control channel readings can display in any units Display units need not match setpoint units NOTE If acurve is not assigned to the control input control reverts to sensor units and the setpoint is set to the most current reading When changing setpoint units while the control loop is active the Model 331 converts the control setpoint to the new control units for minimal disruption in control output Setpoint resolution depends on sensor type and setpoint units With setpoint expressed in temperature setpoint resolution is 0 001 degree for setpoints below 100 and 0 01 for setpoints between 100 and 1000 In sensor units the setpoint resolution matches the display resolution for the sensor input type given in the specifications Table 1 1 The instrument allows a large setpoint range to accommodate a variety of sensors and units With setpoint expressed in sensor units setpoint range is unlimited The user must determine suitability of a setpoint value In temperature units a safety feature limits the setpoint value to help preve
232. oner 7 4 Options and Accessories Lake Shore Model 331 Temperature Controller User s Manual NOTE Customer must use 5 64 2 mm hex key to remove four existing screws from sides of instrument Unit on right side mounting shown Unit on left side also possible Item Description P N Qty 1 Rack Mount Ear 107 440 1 2 Rack Mount Support 107 442 1 3 Rack Mount Panel 107 432 1 4 Rack Mount Handle 107 051 01 2 5 Screw 6 32 x 3 8 Inch 0 033 4 FHMS Phillips 6 Screw 8 32 x 3 8 Inch 0 081 6 FHMS Phillips 0 331 7 3 eps Figure 7 3 Model RM 1 2 Rack Mount Kit Options and Accessories 7 5 Lake Shore Model 331 Temperature Controller User s Manual Refer to Installation Procedure SA Installation Procedure 1 Use 5 64 inch 2 mm hex key to remove two 6 32 x 1 4 black button head screws from side of instrument 2 Place Instrument on shelf 3 Use 5 64 inch 2 mm hex key to reinstall two 6 32 x 1 4 black button head screws through side of rack into corresponding holes in the side of the instrument C 331 7 4 eps Figure 7 4 Model RM 2 Dual Rack Mount Shelf 7 6 Options and Accessories 8 0 8 1 8 1 1 Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 8 SERVICE GENERAL This chapter describes the service for the Model 331 Temperature Controller Paragraph 8 1 provides a description of Electrostatic Discharge ESD line voltage selection in Pa
233. operation is used to enter a new curve or edit an existing user curve Only user curves 21 to 41 can be changed Standard curves can only be viewed with the edit operation Entering the identification parameters associated with the curve is as important as entering the breakpoints Curve header parameters are listed in Table 5 1 Typical parameters for common sensors are listed in Table 5 2 Read this section completely and gather all necessary data before beginning the process NOTE If the curve you wish to enter has similar parameters to an existing curve first copy the similar curve as described in Paragraph 5 2 3 to a new location then edit the curve to the desired parameters To enter a new user curve or edit an existing user curve press the Curve Entry key Press the A or Y key until you see the following display Edit Press the Enter key Press the Escape key anytime during this routine to return to the normal display i F Use the A or Y key to cycle through the various curves Curve numbers 21 thru 41 are used to copy or create new curves You can also view but not modify the standard curve numbers 01 thru 20 from here For this example we will enter a new curve in location 21 Press the Enter key Use the numerical keypad to enter the applicable sensor serial number to a maximum of 10 digits For this example we will enter 0123456789 Press the Enter key L i A Use the A or Y key to cycle through the curve formats V K Q K log Q K
234. or Thermocouple Ranges A 8 15 B 1 Temperature Conversion Table miooo A A ic B 2 C 1 Comparison of Liquid Helium and Liquid Ntrogen nono nono non cnn nano ncnr non nr ronca C 1 D 1 DT 470 Silicon Diode Curve ui eed he eee Sie dives D 1 D 2 DI 670 Silicon Diode Curves piu ta ii D 2 D 3 DT 500 Series Silicon Diode Curves ooococccccnnoconocononcnnnonnncnnnonnnnnnnnn nn cnn nn nrnnn nn rr nan nn nana n nn rn nan diuca dea dade ddnei ini D 2 D 4 PT 100 1000 Platinum RTD CUIVOS i sseccces cc sesh eitpereacen es avhans socenenensscosewevsseevobobcetukantebbue duane sosusarsuatenesavientete D 3 D 5 RX 102A RO MCU neta niin hentia E ein ala chives D 4 D 6 RX 202A ROX M CHE ii A Ad D 5 D 7 Type K Thermocouple Curve iii ds D 6 D 8 Type E Thermocouple CUNE uiioiiros datan Ke EEN EENS dE EEN AER D 7 D 9 Type T Thermocouple e D 8 D 10 Chromel AuFe 0 03 Thermocouple Curve coooococcccccnnoccnonononononononcnanonnnr nono nnn nan n nn rra n nr ren rre D 9 D 11 Chromel AuFe 0 07 Thermocouple Curve cooococccccconoccnonononcnononcncnanonnncnnnnn nro ran nn nr nnne nn rr nan nn nara nr nr naar rre D 10 vi Table of Contents Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 1 INTRODUCTION 1 0 GENERAL This chapter provides an introduction to the Model 331 Temperature Controller The Model 331 was designed and manufactured in the United States of America by Lake Shore Cryotronics Inc The Model 331 Temperature Controller is a micro
235. ources like thermal radiation and heat conducting through mounting structures can cause gradients For best accuracy sensors should be positioned near the sample so that little or no heat flows between the sample and sensor This may not however be the best location for temperature control as discussed below Thermal Conductivity The ability of heat to flow through a material is called thermal conductivity Good thermal conductivity is important in any part of a cryogenic system that is intended to be the same temperature Copper and aluminum are examples of metals that have good thermal conductivity while stainless steel does not Non metallic electrically insulating materials like alumina oxide and similar ceramics have good thermal conductivity while G 10 epoxy impregnated fiberglass does not Sensor packages cooling loads and sample holders should have good thermal conductivity to reduce temperature gradients Surprisingly the connections between thermally conductive mounting surfaces often have very poor thermal conductivity Contact Area Thermal contact area greatly affects thermal conduction because a larger area has more opportunity to transfer heat Even when the size of a sensor package is fixed thermal contact area can be improved with the use of a gasket material A soft gasket material forms into the rough mating surface to increase the area of the two surfaces that are in contact Good gasket materials are soft thin and hav
236. output is related to the error signal in three ways Proportional gain acts on the instantaneous error as a multiplier Integral reset acts on the area of error with respect to time and can eliminate control offset or droop Derivative rate acts on the rate of change in error to dampen the system reducing overshoot quench A condition where the superconducting magnet goes normal i e becomes non superconductive When this happens the magnet becomes resistive heat is generated liquid cryogen is boiled off and the magnet power supply is shut down due to the sudden increase in current demand rack mount An instrument is rack mountable when it has permanent or detachable brackets that allow it to be securely mounted in an instrument rack The standard rack mount is 19 inches wide A full rack instrument requires the entire width of the rack Two half rack instruments fit horizontally in one rack width relief valve A type of pressure relief device which is designed to relieve excessive pressure and to reclose and reseal to prevent further flow of gas from the cylinder after reseating pressure has been achieved A 6 Glossary of Terminology Lake Shore Model 331 Temperature Controller User s Manual remanence The remaining magnetic induction in a magnetic material when the material is first saturated and then the applied field is reduced to zero The remanence would be the upper limit to values for the remanent induction Note that
237. over the high end of the curve T Under Input at or under the low end of the curve No heater load is connected to the rear panel heater terminals HTE Most commonly repaired by checking the heater connections UFen May also be caused by a loose connection or malfunctioning component within the instrument HTE Fail Internal component malfunction Contact Lake Shore Defective HOWRAM Defective NOVRAM Contact Lake Shore Invalid data or contents in NOVRAM Press and hold the Invalid HOLURARN Escape key for 20 seconds to initialize NOVRAM Refer to Paragraph 4 21 8 8 Service Lake Shore Model 331 Temperature Controller User s Manual U23 U22 yao ER O cala Sie A Ta E PE Zidi P 331 8 7 bmp Figure 8 7 Location Of Internal Components 8 9 Service 8 9 8 9 1 Lake Shore Model 331 Temperature Controller User s Manual CALIBRATION PROCEDURE The Model 331 requires calibration of both of the sensor inputs and analog output to operate within specification None of the other circuits require calibration The sensor inputs may be configured as diode resistor or thermocouple and the calibration process differs for each This procedure contains instructions for both input types The analog output calibration is necessary for the Model 331S only and may be ignored for the Model 331E Refer to Paragraph 8 9 5 for details on calibration specific interface commands Equipment Required for Calibra
238. p to configure 1 or 2 lt zone gt Specifies which zone in the table to configure Valid entries are 1 10 lt top value gt Specifies the top temperature of this zone lt P value gt Specifies the P for this zone 0 1 to 1000 lt I value gt Specifies the for this zone 0 1 to 1000 lt D value gt Specifies the D for this zone 0 to 200 lt mout value gt Specifies the manual output for this zone 0 to 100 lt range gt Specifies the heater range for this zone if lt loop gt 1 Valid entries 0 3 Configures the control loop zone parameters Refer to Paragraph 2 9 ZONE 1 1 25 0 10 20 0 0 2 term Control Loop 1 zone 1 is valid to 25 0 K with P 10 20 D 0 and a heater range of 2 Control Loop Zone Table Parameter Query ZONE lt loop gt lt zone gt term n nn lt loop gt Specifies which loop to query 1 or 2 lt zone gt Specifies which zone in the table to query Valid entries 1 10 lt top value gt lt P value gt lt I value gt lt D value gt lt mout value gt lt range gt term nnnnnn tnnnnnn tznnnnnn tnnnnnn tnnnnnn n Refer to command for description Remote Operation 6 39 Lake Shore Model 331 Temperature Controller User s Manual This Page Intentionally Left Blank 6 40 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 7 OPTIONS AND ACCESSORIES 7 0 GENERAL This chapter provides Model 331 Temperature Controller options and ac
239. parameters have been chosen for a given setpoint the whole process may have to be done again for other setpoints significantly far away that have different tuning needs Trying to remember when to use which set of tuning parameters can be frustrating The Model 331 has a Zone feature as one of its tuning modes that can help To use the Zone feature the user must determine the best tuning parameters for each part of the temperature range of interest The parameters are then entered into the Model 331 where up to ten zones can be defined with different P I D heater range and manual heater settings A setpoint setting is assigned as the maximum temperature for that zone The minimum temperature for a zone is the setpoint for the previous zone O K is the starting point for the first zone When the Zone tuning mode is on each time the setpoint is changed to a new temperature appropriate control parameters are chosen automatically Control parameters can be determined manually or by using the AutoTune feature AutoTune is a good way to determine a set of tuning parameters for the control system that can then be entered as zones Once the parameters are chosen AutoTune is turned off and zone tuning takes over Zone tuning has advantages over AutoTune during normal operation When a new setpoint is set the zone tuning automatically sets the appropriate control parameters for the destination Approach to the new setpoint is controlled with the best parame
240. plied by the Model 331 is determined by the user selection of Negative Temperature Coefficient NTC 10 pA or Positive Temperature Coefficient PTC 1 mA To setup a resistor sensor input press the Input Setup key The first screen appear as follows T Use the A or Y key to toggle between Input A and B Press the Enter key d ipu LH Aa Use the A or Y key to cycle through the sensor types shown in Table 4 1 with 1000 Plat 250 100 Plat 500 100022 Plat and NTC RTD being the relevant choices Press the Enter key Thermal EMF Compensation To keep power low and avoid sensor self heating the sensor excitation is kept low There are two major problems that occur when measuring the resulting small DC voltages The first is external noise entering the measurement through the sensor leads which is discussed with sensor setup The second problem is the presence of thermal EMF voltages sometimes called thermocouple voltages in the lead wiring Thermal EMF voltages appear whenever there is a temperature gradient across a piece of voltage lead Thermal EMF voltages must exist because the sensor is almost never the same temperature as the instrument They can be minimized by careful wiring making sure the voltage leads are symmetrical in the type of metal used and how they are joined and by keeping unnecessary heat sources away from the leads Even in a well designed system thermal EMF voltages
241. power as resistive heater load and includes two lower ranges for systems with less cooling power Heater output is short circuit protected to prevent instrument damage if the heater load is accidentally shorted The setpoint ramp feature allows smooth continuous changes in setpoint and can also make the approach to a setpoint temperature more predictable The zone feature can automatically change control parameter values for operation over a large temperature range Values for ten different temperature zones can be loaded into the instrument which will select the next appropriate value on setpoint change Introduction Lake Shore Model 331 Temperature Controller User s Manual Product Definition Continued Interface The most frequently used functions can be accomplished from the instrument front panel with one or two keystrokes Nearly every function on the instrument front panel can also be performed via computer interface The Model 331E is equipped with a serial RS 232C Interface while the Model 331S also includes a parallel IEEE 488 Interface Maximum reading rates can be achieved with either interface Both versions include Model 330 command emulation mode for drop in interchangeability with Model 330 Temperature Controllers in existing systems High and low alarms for each input can be used in latching mode requiring user intervention before alarms reset For the Model 331S alarms can also be used in conjunction with relays in non
242. processor based instrument with digital control of a variable current output The Model 331 features include the following e Two Models Available Model 331S Standard Instrument adds IEEE 488 interface and Relay Analog Output Model 331E Economy Instrument e Two Sensor Inputs Supporting Diodes Positive Temperature Coefficient PTC Resistance Temperature Detectors RTDs Negative Temperature Coefficient NTC RTDs Thermocouples e Five Tuning Modes Autotuning P Autotuning PI Autotuning PID Manual Zone 10 Temperature Zones Two Temperature Control Loops Loop 1 50 W Output Loop 2 1 W Output e Bright Large Character Display 2 Row by 20 Character Vacuum Fluorescent Display Display of Sensor Temperature in K C or sensor units in volts ohms Model 330 Command Emulation Mode Serial Interface RS 232C Electrical Format IEEE 488 Interface Model 331S Only Relays and Analog Voltage Output Terminal Block Model 331S Only LakeShore 331 Temperature Controller Control A Tune Remote 00000 00 222 00000 0000000 ee Control Zone Input Display Alarm Remote Escape Heater Setup Setting Setup Format Local H Range La C PID Curve Analog Setpoint M Math Output Interface Enter Loop al A A SC C331 1 1 eps Figure 1 1 Model 331 Temperature Controller Front Panel Introduction 1 1 1 1 Lake Shore Model 331 Temperature Controller User s Manua
243. pters 4018 E y Ports COM amp LPT Interface Termination Methods Timeouts SS zB System devices GPIBO y IV Send EOI at end of Write 140 E TeminateReadoneas 10c 2 GPIB Address od Ed Serial Pol Primary IV Set EO with EOS on Write fisc 8 KS 1sec E 12 y ine Properties Refresh A T 8 bit EOS Compare Secondary NONE y fi 0 EOS Byte M Readdress Figure 6 2 DEV 12 Device Template Configuration 6 6 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual 6 1 4 2 Visual Basic IEEE 488 Interface Program Setup This IEEE 488 interface program works with Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better lt assumes your IEEE 488 GPIB card is installed and operating correctly refer to Paragraph 6 1 4 1 Use the following procedure to develop the IEEE 488 Interface Program in Visual Basic 1 Start VB6 2 Choose Standard EXE and select Open 3 Resize form window to desired size 4 On the Project Menu select Add Module select the Existing tab then navigate to the location on your computer to add the following files Niglobal bas and Vbib 32 bas 5 Add controls to form a Add three Label controls to the form b Add two TextBox controls to the form c Add one CommandButton control to the form 6 Onthe View Menu sel
244. r Lake Shore Model T The normal reading display appears If the instrument does not complete the sequence or if a general error message displays there may be a problem with the line power or the instrument Individual messages in a reading location normally indicate that input setup is required 4 4 Operation Lake Shore Model 331 Temperature Controller User s Manual 4 3 DISPLAY FORMAT AND SOURCE UNITS SELECTION In the normal display the display is divided into four user configurable areas that can provide temperature readings setpoint display and heater status Figure 4 3 illustrates the display location numbering and available selections for each location To change Setpoint units and select Heater Out Power or Current refer to the description of Control Setup in Paragraph 4 7 To change display brightness refer to Paragraph 4 18 Display Location 1 Display Location 2 Input A Input A Input B Input B None None Display Location 3 Display Location 4 Input A Input A Input B Input B Setpoint Heater Out None None C 331 4 3 eps Figure 4 3 Display Format Definition To configure a display location press the Display Format key to display the following screen Use the A or Y key to increment or decrement through Display Locations 1 thru 4 For this example select Display Location 1 then press the Enter key You will see the following display Use the A or Y ke
245. r GPIB TNT Plug and Play Properties Lx A General GPIB Settings Resources View devices by type View devices by col m Computer Y AT GPIB TNT Plug and Play Q CDROM 1 Disk drives 7154 PrP Serial Number ODAD7FAD o RB Display adapters 4 2 Floppy disk controllers Interface Name r Termination Methods zz Hard disk controllers areo y IV Send EOI at end of Write z Keyboard W o 2 Monitor GPIB Address M Terminate Read on EOS Py Mouse gt y National Instruments GPIB Interfaces Ga M Set EOI with EOS on Wite AT GPIB TNT Plug and Play E 8 bit EOS Compare E 5 Network adapters Secondary 2 Ports COM amp LPT 10 System devices Gel D Ste 1 1 0 Timeout 10sec M Properties Refresh Remove IV System Controller OK Cancel Figure 6 1 GPIB Setting Configuration System Properties 2 x General Device Manager Hardware Profiles Performance 1 View devices by type Y en dad National Instruments GPIB Interfaces Properties 124 x El Computer General Device Templates 9 Zi CDROM H E Disk drives y National Instruments GPIB Interfaces S Display adapters H 6 Floppy disk controllers 0 Hard disk controllers ee Keyboard E O Monitor A Mouse National Instruments GPIB Interface o m DEV12 Attributes E Network ada
246. r in free air This power may need to be derated if used in a vacuum where convection cooling can not take place and it is not adequately heat sinked to a cooled surface Cooling System Design 2 7 2 4 2 2 4 3 2 4 4 2 5 2 5 1 2 5 2 Lake Shore Model 331 Temperature Controller User s Manual Heater Location For best temperature measurement accuracy the heater should be located so that heat flow between the cooling power and heater is minimized For best control the heater should be in close thermal contact with the cooling power Geometry of the load can make one or both of these difficult to achieve That is why there are several heater shapes and sizes Heater Types Resistive wire like nichrome is the most flexible type of heater available The wire can be purchased with electrical insulation and has a predictable resistance per given length This type of heater wire can be wrapped around a cooling load to give balanced even heating of the area Similar to sensor lead wire the entire length of the heater wire should be in good thermal contact with the load to allow for thermal transfer Heat sinking also protects the wire from over heating and burning out Resistive heater wire is also wound into cartridge heaters Cartridge heaters are more convenient but are bulky and more difficult to place on small loads A typical cartridge is 1 4 inch in diameter and 1 inch long The cartridge should be snugly held in a hole in the l
247. ragraph 8 2 fuse replacement in Paragraph 8 3 rear panel connector definitions in Paragraph 8 4 top of enclosure remove and replace procedure in Paragraph 8 5 firmware and NOVRAM replacement in Paragraph 8 6 jumpers in Paragraph 8 7 error messages in Paragraph 8 8 and calibration procedure in Paragraph 8 9 ELECTROSTATIC DISCHARGE Electrostatic Discharge ESD may damage electronic parts assemblies and equipment ESD is a transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field The low energy source that most commonly destroys Electrostatic Discharge Sensitive ESDS devices is the human body which generates and retains static electricity Simply walking across a carpet in low humidity may generate up to 35 000 volts of static electricity Current technology trends toward greater complexity increased packaging density and thinner dielectrics between active elements which results in electronic devices with even more ESD sensitivity Some electronic parts are more ESDS than others ESD levels of only a few hundred volts may damage electronic components such as semiconductors thick and thin film resistors and piezoelectric crystals during testing handling repair or assembly Discharge voltages below 4000 volts cannot be seen felt or heard Identification of Electrostatic Discharge Sensitive Components The following are various industry symbols
248. rance of 0 0010 VDC and record this positive full scale FS value Determine the gain calibration constant by negating the FS reading obtained in Step 3 and adding the FS reading to the result and then dividing that number into 20 Use the CALG command to send the gain calibration constant EXAMPLE FS DMM Reading 10 0432 FS DMM Reading 10 0564 Gain Constant Calculation 20 10 0432 10 0564 0 99504 Calibration Command CALG V 1 0 99504 9 Send the CALSAVE command to save the constants in the E prom 8 9 5 Calibration Specific Interface Commands CALG Gain Calibration Constant Command Input CALG lt input gt lt type gt lt value gt term Format a nn tnnnnnnn lt input gt Specifies which input or analog output the gain calibration constant will be provided to Valid entries are A or B for inputs and V for the analog output lt type gt Specifies the input sensor type Valid entries are 0 Silicon Diode 6 Thermo 25mV 1 GaAlAs Diode or Analog Output 7 Thermo 50mV 2 1000 Plat 250 Reversal Off 10 100 Plat 250 Reversal On 3 100Q Plat 500 Reversal Off 11 1000 Plat 500 Reversal On 4 1000 Plat Reversal Off 12 1000Q Plat Reversal On 5 NTC RTD Reversal Off 13 NTC RTD Reversal On lt value gt Gain calibration constant value Remarks Provides the gain calibration constant for the selected input or analog output CALG Gain Calibration Constant Query
249. rature Controller User s Manual Input Type Parameter Query INTYPE lt input gt term a lt input gt Specifies input to query A or B lt sensor type gt lt compensation gt term n n Refer to command for description Keypad Status Query KEYST term lt keypad status gt term n 1 key pressed 0 no key pressed Returns keypad status since the last KEYST KEYST returns 1 after initial power up Kelvin Reading Query KRDG lt input gt term a lt input gt Specifies which input to query A or B lt kelvin value gt term innnnnn Also see the RDGST command Linear Equation Data Query LDAT lt input gt term a lt input gt Specifies which input to query A or B lt linear value gt term nnnnnn Also see the RDGST command Input Linear Equation Parameter Command LINEAR lt input gt lt equation gt lt varM value gt lt X source gt lt B source gt lt varB value gt term a n tnnnnnn n n tnnnnnn lt input gt lt equation gt lt varM value gt lt X source gt lt B source gt lt varB value gt Specifies input to configure A or B Specifies linear equation to use Valid entries 1 y mx b 2 y m x b Specifies a value for m in the equation Specifies input data to use Valid entries 1 kelvin 2 Celsius 3 sensor units Specifies what to use for b in the equation To use a setpoint set its units to the sam
250. rature Range for Platinum SoftCal Inputs C 331 5 2 eps Figure 5 2 SoftCal Temperature Ranges for Platinum Sensors One two or three calibration data points can be used If using one point the algorithm shifts the entire curve up or down to meet the single point If using two points the algorithm has enough information to tilt the curve achieving good accuracy between the data points The third point extends the improved accuracy to span all three points Point 1 Calibration data point at or near the boiling point of nitrogen 77 35 K Temperatures outside 50 K to 100 K are not allowed Point 2 Calibration data point near room temperature 305 K Temperatures outside 200 K to 350 K are not allowed Point 3 Calibration data point at a higher temperature 480 K Temperatures outside 400 K to 600 K are not allowed SoftCal Accuracy With Platinum Sensors A SoftCal calibration is only as good as the accuracy of the calibration points The accuracies listed for SoftCal assume 0 05 K for 77 35 K liquid nitrogen and 305 K room temperature points Users performing the SoftCal with Lake Shore instruments should note that the boiling point of liquid cryogen though accurate is affected by atmospheric pressure Use calibrated standard sensors if possible One point SoftCal calibrations with platinum sensors have no specified accuracy Two point SoftCal calibrations for applications above 70 K are performed at liquid nitrogen 77
251. re Model 331 Temperature Controller User s Manual Slides into slot at rear of Model 331 Use screwdriver to lock or unlock wires Terminal Block Connector Lake Shore P N 106 739 Insert wire into slot C 331 8 4 eps Pin Description Relay 1 Normally Closed NC Relay 1 Common COM Relay 1 Normally Open NO Relay 2 Normally Close NC Relay 2 Common COM Relay 2 Normally Open NO Analog Voltage Output Hi Analog Voltage Output Lo 0 JO Om P Go bh A Figure 8 4 RELAYS and ANALOG OUPUT Terminal Block RS 232 DTE F 331 8 5 eps Model 331 Temperature Controller Typical Computers DE 9P DTE DB 25P DTE Pin Description Pin Description Pin Description __ No Connection Receive Data RD in Transmit Data TD out 4 Data Terminal Ready DTR out 5 Ground GND e DsR n s GND 6 Data Set Ready DSRin _ 7 GND 6 DRM 7 Data Terminal Ready DTR out tied to 4 8 DCD in 7 RTS out BCEE tout Pers ny 9 No Connection 22 _Ringin iny 9 Ringiin in Figure 8 5 RS 232 Connector Details 8 4 Service Lake Shore Model 331 Temperature Controller User s Manual 8 4 1 Serial Interface Cable Wiring The following are suggested cable wiring diagrams for connecting the Model 331 Serial Interface to various Customer Personal Computers PCs Model 331 to PC Serial Interface PC with DE 9P Model 331 DE 9P Stand
252. res above 500 K The voltage range for Inputs A and B is set independently To setup a thermocouple sensor input press the Input Setup key The first screen appear as follows Use the A or Y key to toggle between Input A and B Press the Enter key Use the A or Y key to cycle through the sensor types shown in Table 4 1 with Thermo 25mV and Thermo 50mV being the relevant choices Press the Enter key Proceed to Paragraph 4 4 3 1 to select a room temperature compensation or press the Escape key to return to the normal display Room Temperature Compensation Room temperature compensation is required to give accurate temperature measurements with thermocouple sensors lt corrects for the temperature difference between the instrument thermal block and the curve normalization temperature of O C An external ice bath is the most accurate form of compensation but is often inconvenient The Model 331 has built in room temperature compensation that is adequate for most applications The built in compensation can be turned on or off by the user It operates with any thermocouple type that has an appropriate temperature response curve loaded Room temperature compensation is not meaningful for sensor units measurements NOTE Room temperature compensation should be calibrated as part of every installation To turn room temperature compensation on or off press the Input Setup and press Enter until the following display
253. res calibrated By Type By Type sensor sensor sensor 485 Q K at105K 4223 Q Kat4 2K 2290 Q K at4 2K 12 6 VIK at 4 2 K 0 92 uV K at 4 2 K 0 84 Q K at200K 0 098 Q Kat77K 2 15 Q K at77K 22 4 uV K at 300 K 40 pV K at 300 K 0 037 Q K at 300K 0 0094 Q K at300K 0 131 Q K at 300 K 36 pV K at 1500 K Typical Sensor Sensitivity R Measurement Resolution Sensor Units Temperature Equivalence Electronic Accuracy Sensor Units Temperature Equivalents Temperature Accuracy including electronic accuracy CalCurve and calibrated sensor Control Stability Sensor Units Temperature Equivalence Magnetic Field Use 40 MQ lt 1 mK at 105 K 48 mK at 200 K 1 081 K at 300 K 10 10 Q 0 04 of reading 4 8 mK at 105 K 131 mK at 200 K 2 729 K at 300 K 32 mK at 105 K 171 mK at 200 K 2 800 K at 40 K 80 MQ 1 mK at 105 K 96 mK at 200 K 2 162 K at 300 K 40 MQ lt 1 mK at 4 2K 408 mK at 77 K 4 255 K at 300 K 0 10 Q 0 04 of reading lt 1 mK at4 2K 1 078 K at 77 K 11 00 K at 300 K 7 mK at 4 2 K 1 138 K at 77 K 11 46 K at 300 K 80 MQ 1 mK at 4 2 K 816 mK at 77 K 8 510 K at 300 K 40 mQ lt 1 mK at 4 2 K 18 6 mK at 77 K 305 mK at 300 K 0 10 Q 0 04 of reading 1 mK at 4 2 K 77 mK at 77 K 881 mK at 300 K 8 mK at 4 2 K 127 mK at 77 K 881 mK at 300 K 80 MQ 1 mK at 4 2K 38 mK at 77 K 610 mK at 300 K Accuracy specification does not include
254. res system characteristics after a setpoint change and calculates P and D The user must set heater range AutoTune will not work in every situation Refer to Paragraphs 2 8 and 4 9 for details Zone Tuning Optimal control parameters values are often different at different temperatures within a system Once values have been chosen for each temperature range or zone the zone feature can automatically select the correct set each time the setpoint is changed This mode does not help choose control parameter values it helps use the values more efficiently Refer to Paragraphs 2 7 and 4 10 for details CONTROL SETUP After the Input Setup has been completed Paragraph 4 4 and Loop is selected Paragraph 4 6 1 the user can begin to setup temperature control parameters Control input is the sensor input that is used for control feedback in closed loop control Either Input A or B can be assigned to either Loop 1 or 2 It is not recommended to assign both loops to one input Control input is ignored when using open loop control mode To change control input press the Control Setup key and the following screen will appear Use the A or Y key to toggle between Input A or B Press the Enter key to accept the setting and continue with additional selections You can press the Escape key anytime to exit the routine 4 14 Operation Lake Shore Model 331 Temperature Controller User s Manual Control Setup Continued The con
255. rm Send command to instrument If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If InStr strCommand lt gt 0 Then Check to see if query strReturn Space 100 Build empty return buffer Call ibrd intDevice strReturn Read back response If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If strReturn lt gt Then Check if empty string strReturn RTrim strReturn Remove extra spaces and Terminators Do While Right strReturn 1 Chr 10 Or Right strReturn 1 Chr 13 strReturn Left strReturn Len strReturn 1 Loop Else strReturn No Response Send No Response End If frmIEEE txtResponse Text strReturn Put response in text on main form End If Loop End Sub Remote Operation 6 9 6 1 4 3 6 1 4 4 Lake Shore Model 331 Temperature Controller User s Manual IEEE 488 Interface Board Installation for Quick Basic Program This procedure works on an IBM PC or compatible running DOS or in a DOS window This example uses the National Instruments GPIB PCII IIA card Install GPIB PCII IIA card using National Instruments instructions Install NI 488 2 software for DOS Version 2 1 1 was used for the example Verify that config sys contains the command device gpib pc gpib com Reboot the computer Run IBTEST to test software configuration Do nat install the instrument before running IBTEST
256. rm also called reset looks at error over time to build the integral contribution to the output Output I PI f e dt By adding the integral to proportional contributions the error that is necessary in a proportional only system can be eliminated When the error is at zero controlling at the setpoint the output is held constant by the integral contribution The integral setting I is more predictable than the gain setting It is related to the dominant time constant of the load As discussed in Paragraph 2 7 3 measuring this time constant allows a reasonable calculation of the integral setting In the Model 331 the integral term is not set in seconds like some other systems The integral setting can be derived by dividing 1000 by the integral seconds lseting 1000 Iseconas Derivative D The derivative term also called rate acts on the change in error with time to make its contribution to the output de Output D PD put D ot By reacting to a fast changing error signal the derivative can work to boost the output when the setpoint changes quickly reducing the time it takes for temperature to reach the setpoint It can also see the error decreasing rapidly when the temperature nears the setpoint and reduce the output for less overshoot The derivative term can be useful in fast changing systems but it is often turned off during steady state control because it reacts too strongly to small disturbances The derivative s
257. rmal Conductivity EE 2 5 2 3 4 Contact Areas as setccnccecs E E ed docs adecco ties 2 5 2 3 5 Contact Pressure wen fii ciate a nny ias 2 6 2 3 6 ET o WAG gie eech dace seis EEN 2 6 2 3 7 LOA Ee e EE 2 7 2 3 8 Heat Sinking UE 2 7 2 3 9 Thermal RAGAUON s sirena vex idk sede te cagate eats aida 2 7 2 4 HEATER SELECTION AND INSTALLATION A 2 7 2 4 1 Heater Resistance and Power 2 c ccccececcecesseccecsedeeseesndandeedeceedesseeebdesdaceedecceeetestdaedeedndeedeneedensecie 2 7 2 4 2 Heater Loca cerca dadas 2 8 2 4 3 eater TYPOS ile 2 8 2 4 4 eater WV IFING EE 2 8 2 5 CONSIDERATIONS FOR GOOD CONTROL coooocccococoncnononcnonanannnnononnnnnnnonnnnnnnnncnn nan rra nan nn nr nnnr rr rrnnnn 2 8 2 5 1 Thermal Conductivity iii dives dn va ie de ei ee 2 8 2 5 2 WIS MANAG EEN 2 8 2 5 3 Two Se nsor Approach seceecceseccrecweeteeg tuged ea 2 9 2 5 4 BREET 2 9 2 5 5 System ul TEEN 2 9 2 6 PID CONTROL cota ia ana 2 9 2 6 1 ProportionalMP li eege Ee EE de EE oe 2 10 2 6 2 Integral Marraco dada ta dada italia ada 2 10 2 6 3 REI CL EE 2 10 2 6 4 Manual Heater Power MHP Output 2 10 2 7 MANUALSTUNING a eege eessen el e Ee 2 12 2 7 1 Setting Heater Range 2000 A diese deeg eege dree Cde egen 2 12 2 7 2 T ing Hiel 2 12 2 7 3 PUNING Ide gral ii 2 13 2 7 4 TUI e H RE 2 13 2 8 AUTOTUNIN G oiite a aaae Aaaa Aa tidad 2 13 2 9 ZONE TUNING wisn ease aa a ee i Mai a 2 14 Table of Contents Lake Shore Model 331 Temperature Controller User s Manual TAB
258. rminators or an unsupported command Execution Error EXE Bit 4 This bit is set if the EXE bit is set an execution error has been detected This occurs when the instrument is instructed to do something not within its capabilities Device Dependent Error DDE Bit 3 This bit is set if a device dependent error has been detected if the DDE bit is set The actual device dependent error can be found by executing the various device dependent queries Query Error QYE Bit 2 This bit indicates a query error It occurs rarely and involves loss of data because the output queue is full Operation Complete OPC Bit 0 This bit is generated in response to the OPC common command It indicates when the Model 331 has completed all selected pending operations It is not related to the OPC command which is a separate interface feature IEEE Interface Example Programs Two BASIC programs are included to illustrate the IEEE 488 communication functions of the instrument The first program was written in Visual Basic Refer to Paragraph 6 1 4 1 for instructions on how to setup the program The Visual Basic code is provided in Table 6 2 The second program is written in Quick Basic Refer to Paragraph 6 1 4 3 for instructions on how to setup the program The Quick Basic code is provided in Table 6 3 Finally a description of operation common to both programs is provided in Paragraph 6 1 4 5 While the hardware and software required to
259. rmocouple sensor inputs being Model 331X T1 or T2 Sensor connection is important when using thermocouples because the measured signal is small Many measurement errors can be avoided with proper sensor installation CAUTION Do not leave thermocouple inputs unconnected Short inputs when not in use Sensor Input Terminals Attach sensor leads to the screws on the off white ceramic terminal blocks Each block has two screw terminals one positive on the I V side of the connector one negative on the V side of the connector See Figure 3 4 The current and voltage references silkscreened on the back panel are for the diode resistor connectors For thermocouples the positive wire goes to the left side terminal and the negative wire to the right side terminal Remove all insulation then tighten the screws on the thermocouple wires Keep the ceramic terminal blocks away from heat sources including sunlight and shield them from fans or room drafts Thermocouple Positive Terminal Thermocouple Negative Terminal rd Common Thermocouple Polarities Positive Negative Type K Nickel Chromium vs Nickel Aluminum Chromel YEL Alumel RED Type E Nickel Chromium vs Copper Nickel Chromel PUR Constantan RED Type T Copper vs Copper Nickel Copper BLU Constantan RED Chromel AuFe 0 03 Chromel Gold Chromel AuFe 0 07 Chromel Gold Figure 3 4 Thermocouple Input Definition and Common
260. rned on the instrument will update the control settings each time the setpoint is changed to a new zone If the settings are changed manually the controller will use the new setting while it is in the same zone and update to the zone table settings when the setpoint is changed to a value outside that zone To enter parameter values into the zone table press the Zone Settings key You will see the following display Use the A or Y key to cycle through the ten zones Once the desired zone is displayed press the Enter key You will see the next display The upper setpoint limit is entered using the numeric keypad which includes the numbers 0 9 and decimal point During numeric entry you can press the Escape key one time to clear the entry and a second time to exit to the normal display NOTE The default setting for all the zone setpoints is zero 0 The Model 331 will not search for additional zones once it encounters a setpoint of zero Press the Enter key to accept the new upper limit You will see the next display 3 C3 The Proportional P value is entered using the numeric keypad which includes the numbers 0 9 and decimal point Proportional has a range of 0 1 to 1000 with a default of 50 Press the Enter key to accept the new setting You will see the next display Operation 4 19 Lake Shore Model 331 Temperature Controller User s Manual Zone Settings Continued
261. rogen environment Then plug the control sensor connector in INPUT A and the sample sensor connector in INPUT B Details of sensor hardware connections are detailed in Paragraph 3 5 5 Connect the heater to the banana jacks labeled HEATER OUTPUT A 50 heater allows the maximum power output of 50 W Details of heater installation are provided in Paragraphs 2 4 and 3 7 6 Ensure any other rear panel connections are connected before applying power to the unit For the Model 331E this includes RS 232 Paragraph 6 2 1 For the Model 331S this includes the IEEE 488 Paragraph 8 4 2 Analog Output Paragraph 3 8 and Relays Paragraph 3 9 7 Plug line cord into receptacle 8 Turn the power switch to the on I position The front panel will briefly display the following emm The front panel display is divided into four areas The default display settings place the Sensor A reading in the upper left the Sensor B reading in the upper right the Setpoint in the lower left and the heater output of Loop 1 in percent in the lower right All temperature readings are in Kelvin Each of these display areas is individually configurable by pressing the Display Format key and following the instructions in Paragraph 4 3 Installation 3 11 Lake Shore Model 331 Temperature Controller User s Manual Initial Setup and System Checkout Procedure Continued NOTE For rated accuracy the instrument should warm
262. rol The Model 331 automates the tuning process of typical cryogenic systems with the AutoTune feature For additional information about the algorithm refer to Paragraph 2 8 Before initiating AutoTune the cooling system must be set up properly with control sensor and heater making it capable of closed loop control AutoTune works only with one control loop at a time and does not set the manual heater power output or heater range The control sensor must have a valid temperature response curve assigned to it An appropriate heater range must also be determined as described in Paragraph 2 7 1 Choosing good initial control parameters by experimenting with Manual PID tuning can speed up the AutoTune process If no initial parameters are known start with the default values of P 50 and 20 It is better to set an initial P value that causes the system to be more active than desired Starting with a low P value can increase the time and number of attempts required to tune There are three AutoTune modes available They result in slightly different system characteristics Auto Pl is recommended for most applications Auto P Sets only the P parameter value and D are set to 0 no matter what the initial values are This mode is recommended for systems that have very long lag times or nonlinearity that prevents stable PI control Expect some overshoot or undershoot of the setpoint and stable temperature control below the setpoint value Auto PI
263. rom the instrument including the terminators e Guarantee that no other communication is started during the response or for 50 ms after it completes e Not initiate communication more than 20 times per second Failure to follow these simple rules will result in inability to establish communication with the instrument or intermittent failures in communication Changing Baud Rate To use the Serial Interface you must first set the Baud rate Press Interface key to display the following screen Press the A or Y key to cycle through the choices of 300 1200 or 9600 Baud Press the Enter key to accept the new number 6 16 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual 6 2 7 Serial Interface Example Programs Two BASIC programs are included to illustrate the serial communication functions of the instrument The first program was written in Visual Basic Refer to Paragraph 6 2 7 1 for instructions on how to setup the program The Visual Basic code is provided in Table 6 6 The second program was written in Quick Basic Refer to Paragraph 6 2 7 2 for instructions on how to setup the program The Quick Basic code is provided in Table 6 7 Finally a description of operation common to both programs is provided in Paragraph 6 2 7 3 While the hardware and software required to produce and implement these programs not included with the instrument the concepts illustrated apply to almost any applicat
264. room temperature measured by the thermometer Press the Enter key to save the value 8 To verify calibration check that the temperature reading for the calibrated input matches the room temperature calibration setting value 4 10 Operation 4 5 CURVE SELECTION Lake Shore Model 331 Temperature Controller User s Manual The Model 331 supports a variety of temperature sensors sold by Lake Shore and other manufacturers After the appropriate sensor type is selected for each of the two inputs Paragraph 4 4 an appropriate curve may be selected for each input The 331 can use curves from several sources Standard curves are included with every instrument and numbered 1 20 User curves numbered 21 41 are loaded when a sensor does not match a standard curve CalCurve options are stored as user curves SoftCal calibrations are stored as user curves or user can enter their own curves from the front panel Paragraph 5 2 or computer interface Chapter 6 The complete list of sensor curves built in to the Model 331 is provided in Table 4 2 During normal operation only the curves related to the input type you have selected are displayed If the curve you wish to select does not appear in the selection sequence make sure the curve format matches the recommended format for the input type selected Refer to Table 4 1 NOTE The sensor reading of the instrument can always be displayed in sensor units If a temperature response curve is selected for
265. s If possible the original packing material should be retained for reshipment If not available consult Lake Shore for shipping and packing instructions Installation 3 1 Lake Shore Model 331 Temperature Controller User s Manual 3 3 REAR PANEL DEFINITION This paragraph provides a description of the Model 331 rear panel connections The rear panel consists of the line input assembly RS 232 Connector HEATER OUTPUT Connector INPUT A and B Sensor Input Connectors the RELAY and ANALOG OUTPUT Terminal Block and the IEEE 488 INTERFACE Connector Please read the entire chapter before performing the initial setup and system checkout procedure in Paragraph 3 10 Rear panel connector pin out details are provided in Paragraph 8 4 CAUTION Verify AC Line Voltage shown in the fuse holder window is appropriate for the intended AC power input Also remove and verify the proper fuse is installed before plugging in and turning on the instrument CAUTION Always turn off the instrument before making any rear panel connections This is especially critical when making sensor to instrument connections HEATER OUTPUT HI LO GND NO Ee PARTS a0 He 120 VA 220 240V 0 75 AT 250V 5x20mm RELAYS DUDE SA BEE INPUTA INPUT B JEEE 488 INTERFACE RELAY 1 RELAY 2 OUTPUT CI EELEE F 331 3 1 eps Description Details O Line Input Assembly Paragraph 3 4 Figure 8 1 RS 232 DTE 9 pin
266. s 1 475 0 0 09062 30 170 0 0 82405 59 031 0 1 10476 2 470 0 0 10191 31 160 0 0 84651 60 030 0 1 10702 3 465 0 0 11356 32 150 0 0 86874 e 029 0 1 10945 4 460 0 0 12547 33 145 0 0 87976 62 028 0 1 11212 5 455 0 0 13759 34 140 0 0 89072 63 027 0 1 11517 6 450 0 0 14985 35 135 0 0 90161 64 026 0 1 11896 7 445 0 0 16221 36 130 0 0 91243 65 025 0 1 12463 8 440 0 0 17464 37 125 0 0 92317 66 024 0 1 13598 9 435 0 0 18710 38 120 0 0 93383 67 023 0 1 15558 10 430 0 0 19961 39 115 0 0 94440 68 022 0 1 17705 11 420 0 0 22463 40 110 0 0 95487 69 021 0 1 19645 12 410 0 0 24964 41 105 0 0 96524 70 019 5 1 22321 13 400 0 0 27456 42 100 0 0 97550 71 017 0 1 26685 14 395 0 0 28701 43 095 0 0 98564 72 015 0 1 30404 15 380 0 0 32417 44 090 0 0 99565 73 013 5 1 33438 16 365 0 0 36111 45 085 0 1 00552 74 012 5 1 35642 17 345 0 0 41005 46 080 0 1 01525 75 011 5 1 38012 18 330 0 0 44647 47 075 0 1 02482 76 010 5 1 40605 19 325 0 0 45860 48 070 0 1 03425 77 009 5 1 43474 20 305 0 0 50691 49 065 0 1 04353 78 008 5 1 46684 21 300 0 0 51892 50 058 0 1 05630 79 007 5 1 50258 22 285 0 0 55494 51 052 0 1 06702 80 005 2 1 59075 23 265 0 0 60275 52 046 0 1 07750 81 004 2 1 62622 24 250 0 0 63842 53 040 0 1 08781 82 003 4 1 65156 25 235 0 0 67389 54 039 0 1 08953 83 002 6 1 67398 26 220 0 0 70909 55 036 0 1 09489 84 002 1 1 68585 27 205 0 0 74400 56 034 0
267. s and tasteless gases Gaseous nitrogen makes up about 78 percent of the Earth s atmosphere while helium comprises only about 5 ppm Most helium is recovered from natural gas deposits Once collected and isolated the gases will liquefy when properly cooled A quick comparison between LHe and LN is provided in Table C 1 Table C 1 Comparison of Liquid Helium and Liquid Nitrogen PROPERTY LIQUID HELIUM LIQUID NITROGEN Boiling Point 1 atm in K Thermal Conductivity Gas w cm K Latent Heat of Vaporization Btu liter Liquid Density pounds liter HANDLING CRYOGENIC STORAGE DEWARS Cryogenic containers dewars must be operated in accordance with the manufacturer instructions Safety instructions will also be posted on the side of each dewar Cryogenic dewars must be kept in a well ventilated place where they are protected from the weather and away from any sources of heat A typical cryogenic dewar is shown in Figure C 1 NON MAGNETIC LIQUID HELIUM NON FLAMMABLE KEEP UPRIGHT Dewar eps Figure C 1 Typical Cryogenic Storage Dewar Handling LHe and LN2 C 1 Lake Shore Model 331 Temperature Controller User s Manual C4 0 LIQUID HELIUM AND NITROGEN SAFETY PRECAUTIONS C5 0 Transferring LHe and LN and operation of the storage dewar controls should be in accordance with the manufacturer supplier s instructions During this transfer it is important that all safety prec
268. s two lower ranges for systems with less cooling power Heater output is short circuit protected to prevent instrument damage if the heater load is accidentally shorted Loop 1 Full Scale Heater Power at Typical Resistance Heater Resistance Heater Range Heater Power Low 100 mw 100 Med 1W High 10 W Low 250 mW 25 Q Med 2 5 W High 25 W Low 500 mW 50 Q Med 5W High 50 W NOTE During normal operation if the input type or input curve is changed for the control input the heater will automatically shut off A common error condition that may appear is HTR Open This error message will appear when the heater senses there is no load connected to the rear panel terminals The user can correct this problem by properly connecting a heater load It could also indicate a malfunction internal to the Model 331 such as a loose connection or a malfunctioning component but this is much less likely Other error messages are summarized in Paragraph 8 8 Specifications of heater output are provided in Paragraph 1 3 Instrument Specifications Heater theory of operation is provided in Paragraph 2 4 Heater Selection and Installation Various Heater installation considerations are provided in Paragraph 3 7 Heater Output Setup The Model 331S only has the additional ability to configure the analog output as a variable DC voltage source capable of a 1 W output Once control setup parameters are configured Paragrap
269. s 1 dyne volt V The difference of electric potential between two points of a conductor carrying a constant current of one ampere when the power dissipated between these points is equal to one watt volt ampere VA The SI unit of apparent power The volt ampere is the apparent power at the points of entry of a single phase two wire system when the product of the RMS value in amperes of the current by the RMS value in volts of the voltage is equal to one VSM Vibrating Sample Magnetometer watt W The SI unit of power The watt is the power required to do work at the rate of 1 joule per second References 1 Sybil P Parker Editor McGraw Hill Dictionary of Scientific and Technical Terms Fifth Edition New York McGraw Hill 1994 IBSN 0 07 113584 7 2 Christopher J Booth Editor The New IEEE Standard Dictionary of Electrical and Electronic Terms IEEE Std 100 1992 Fifth Edition New York Institute of Electrical and Electronics Engineers 1993 IBSN 1 55937 240 0 3 Nelson Robert A Guide For Metric Practice Page BG7 8 Physics Today Eleventh Annual Buyer s Guide August 1994 ISSN 0031 9228 coden PHTOAD A 8 Glossary of Terminology B1 0 B2 0 B3 0 Lake Shore Model 331 Temperature Controller User s Manual APPENDIX B TEMPERATURE SCALES DEFINITION Temperature is a fundamental unit of measurement which describes the kinetic and potential energies of the atoms and molecules of bodies When the energies
270. s also useful whenever a reading of deviation from setpoint is needed Table 4 4 Linear Equation Configuration Equation IN IS B MX B Number Sensor M X B Temp K Temp C The columns settings in Table 4 4 are selected independently Number represents a number entered by the user X can be set to an input reading in sensor units or temperature in kelvin or Celsius SP1 represents setpoint of Loop 1 and similarly for other B settings NOTE When using the linear equations MX B or M X B the user should ensure that the setpoint and x variable units match If the units do not match the instrument will continue calculations but results may not be what is expected To configure a linear equation continue from the math setup screen in Paragraph 4 14 and press the Enter key until the following display appears pa Use the A or Y key to toggle between the two linear equations MX B or M X B where M slope of a line X reading data from a sensor input and B offset of a line E The Linear Variable M is entered using the numeric keypad which includes the numbers 0 9 and decimal point Press the Enter key to accept the new setting You will see the next display Use the A or Y key to toggle between the Linear X Variable Temp C Temp K Sensor Press the Enter key to accept the new setting You will see the next display l g ame aas T a
271. se proper syntax 6 Attempt both Talk and Listen functions If one works but not the other the hardware connection is working so look at syntax terminators and command format If only one message is received after resetting the interface check the repeat addressing setting lt should be enabled Old Installation No Longer Working 1 Power instrument off then on again to see if it is a soft failure 2 Power computer off then on again to see if the IEEE card is locked up 3 Verify that the address has not been changed on the instrument during a memory reset 4 Check all cable connections Intermittent Lockups 1 Check cable connections and length 2 Increase delay between all commands to 50 ms to make sure instrument is not being over loaded Remote Operation 6 13 Lake Shore Model 331 Temperature Controller User s Manual 6 2 SERIAL INTERFACE OVERVIEW The serial interface used in the Model 331 is commonly referred to as an RS 232C interface RS 232C is a standard of the Electronics Industries Association ElA that describes one of the most common interfaces between computers and electronic equipment The RS 232C standard is quite flexible and allows many different configurations However any two devices claiming RS 232C compatibility cannot necessarily be plugged together without interface setup The remainder of this paragraph briefly describes the key features of a serial interface that are supported by the in
272. sensors Lake Shore has devoted much time to developing sensor packages that withstand the temperatures vacuum levels and bonding materials found in typical cryogenic cooling systems Experiments done in magnetic fields are becoming very common Field dependence of temperature sensors is an important selection criteria for sensors used in these experiments This manual briefly qualifies the field dependence of most common sensors in the specifications Table 1 2 Detailed field dependence tables are included in the Lake Shore Temperature Measurement and Control Catalog When available specific data on other environmental factors is also included in the catalog Measurement Accuracy Temperature measurements have several sources of error that reduce accuracy Be sure to account for errors induced by both the sensor and the instrumentation when computing accuracy The instrument has measurement error in reading the sensor signal and error in calculating a temperature using a temperature response curve Error results from the sensor being compared to a calibration standard and the temperature response of a sensor will shift with time and with repeated thermal cycling from very cold temperatures to room temperature Instrument and sensor makers specify these errors but there are things a user can do to maintain good accuracy For example choose a sensor that has good sensitivity in the most critical temperature range as sensitivity can minimize the ef
273. ser Data from either input may be assigned to any of the four locations the user s choice of temperature sensor units and maximum minimum or linear equation results can be displayed Heater range and control output as current or power can also be continuously displayed for immediate feedback on control operation Introduction 1 3 1 2 Lake Shore Model 331 Temperature Controller User s Manual SENSOR SELECTION GUIDE The Lake Shore Temperature Measurement and Control Catalog contains complete information on selecting the appropriate Lake Shore Temperature Sensor for your application A list of sensors that may be used with the Model 331 is provided in Table 1 1 This paragraph provides a brief guideline covering sensors commonly used with the Model 331 Typical performance specifications can be found in Table 1 2 If a specific sensor model is not included in the table use the sensitivity of the sensor at the desired temperature to calculate temperature equivalence for your sensor Silicon Diodes are the best choice for general cryogenic use from 1 4 K to above room temperature Economical to use because they follow a standard curve and are interchangeable in many applications silicon diodes are not suitable for use in ionizing radiation or magnetic fields GaAlAs Diodes offer high sensitivity from 1 4 K to above room temperature with better sensitivity than silicon diodes at temperatures below 25 K They are useful in moderate magnetic
274. set sequence is performed To select a source for Max Min continue from the Math Setup screen in Paragraph 4 14 press the Enter key to see the following display Use the A or Y key to cycle through the data sources The user must select a source for the Max Min feature After selecting the desired source press the Enter key Press the Escape key at any time to return to the normal display The instrument retains values entered prior to pressing the Escape key Press the Math key twice to reset Max Min Max Min automatically resets when the instrument is turned off or parameters related to the input change Operation 4 25 Lake Shore Model 331 Temperature Controller User s Manual 4 14 2 Linear The Model 331 will process either of two simple linear equations for each sensor input MX B or M X B The result can be displayed or directed to the analog voltage output There are two different equations available In each M is a gain or slope X is an input reading and B is an offset or intercept not to be confused with input B The two equations are shown in Table 4 4 The difference between them is subtle The first equation is used to scale the raw reading of an input similar to a temperature response curve when the sensor has linear response The second is better at generating a control signal when a setpoint SP1 or SP2 is selected as B The control signal can then be directed to an analog output The second equation i
275. signal line The Model 331 recognizes two of these messages from the BUS CONTROLLER Remote REN and Interface Clear IFC The Model 331 sends one Uniline Command Service Request SRQ REN Remote Puts the Model 331 into remote mode IFC Interface Clear Stops current operation on the bus SRQ Service Request Tells the bus controller that the Model 331 needs interface service A Multiline Command asserts a group of signal lines All devices equipped to implement such commands do so simultaneously upon command transmission These commands transmit with the Attention ATN line asserted low The Model 331 recognizes two Multiline commands LLO Local Lockout Prevents the use of instrument front panel controls DCL Device Clear Clears Model 331 interface activity and puts it into a bus idle state 6 2 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Bus Control Commands Continued 6 1 2 2 6 1 2 3 6 1 2 4 Finally Addressed Bus Control Commands are Multiline commands that must include the Model 331 listen address before the instrument responds Only the addressed device responds to these commands The Model 331 recognizes three of the Addressed Bus Control Commands SDC Selective Device Clear The SDC command performs essentially the same function as the DCL command except that only the addressed device responds GTL Go To Local The GTL command is used to remove
276. sius Reading Query eee 28 RAMPST Control Loop Ramp Status Query 36 CRVDEL Delete User Curve Cmd eee 28 RANGE Heater Range CMA cococccccoccncconannnncnannnos 37 CRVHDR Curve Header Cmd ecer 29 RANGE Heater Range Query cocccccocccccononccccnnnnnos 37 CRVHDR Curve Header Query escenes 29 RDGST Input Status Query oe eee teers 37 CRVPT Curve Data Point Cmd eee 29 RELAY Relay Control Parameter Cmd 37 CRVPT Curve Data Point Ouer 29 RELAY Relay Control Parameter Query 37 CSET Control Loop Parameter Cmd 30 RELAYST Relay Status Ouer 37 CSET Control Loop Parameter Query 30 REV Input Firmware Revision Query 38 DFLT Factory Defaults Cmd n se 30 SCAL Generate SoftCal Curve Cmd 38 DISPFLD Displayed Field Cmd 30 SETP Control Loop Setpoint Cmd 38 DISPFLD Displayed Field Ouer 30 SETP Control Loop Setpoint Query 38 EMUL 330 Emulation Mode Cmd 31 SRDG Sensor Units Reading Query 38 EMUL 330 Emulation Mode Query 31 TEMP Room Temp Comp Temp Query 39 FILTER Input Filter Parameter Cmd 31 TUNEST Control Loop 1 Tuning Query 39 FILTER Input Filter Parameter Query 31 ZONE Control Loop Zone Table Cmd 39 HTR Heater Output Ouer 31 ZONE Control Loop Zone Table Query 39 Remote Operation 6
277. sponse from the Model 331 If the input not being calibrated is diode resistor leave a 100 KQ resistor attached If the other input is a thermocouple leave a short across the input 10 pA Current Source Calibration and 1 mA Current Source Verification Purpose To calibrate the 10 pA current source to be within the specified tolerance and verify operation of the 1 mA current source Process 1 Configure the input for the Silicon Diode range 2 Accurately determine the value of the 100 kQ resistor using the DMM Determine the calibration value by multiplying the actual resistance of the 100 KQ resistor by 10 pA Example 100 050 kQ x 10x10 A 1 00050 V 3 Attach the 100 kQ resistor to the Model 331 input using proper 4 lead connection techniques configure the DMM to read VDC and attach to the resistor 4 Adjust the current source calibration pot R97 for Input A and R98 for Input B on the Model 331 main board until the DMM reads exactly the value calculated in Step 2 to 0 00002 VDC 5 1 mA Current Source Verification Configure the input for the 100Q Plat 250 range 6 Accurately determine the value of the 1 kQ resistor using the DMM Determine the verification value by multiplying the actual resistance of the 1 kQ resistor by 1 mA 7 Attach the 1 KQ resistor to the Model 331 input using proper 4 lead connection techniques configure the DMM to read VDC and attach to the resistor 8 Verify the voltage across to resistor to b
278. ss Enter or select the Send button with the mouse to send command 17 Type Exit and press Enter to quit 6 18 Remote Operation Lake Shore Model 331 Temperature Controller User s Manual Table 6 6 Visual Basic Serial Interface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Click Routine to handle Send button press gSend True Set Flag to True End Sub Private Sub Form _Load Main code section Dim Dim Dim Dim Dim strReturn As String strHold As String Term As String ZeroCount As Integer strCommand As String frmSerial Show Term Chr 13 Chr 10 ZeroCount 0 strReturn strHold If frmSerial MSComml PortOpen frmSerial MSComm1 PortOpen End If frmSerial MSComm1 CommPort 1 frmSerial MSComml Settings frmSerial MSComml Inputlen 1 frmSerial MSComml PortOpen True Do Do DoEvents Loop Until gSend True gSend False strCommand frmSerial txtCommand Text strReturn strCommand UCase strCommand If strCommand EXIT Then End End If frmSerial MSComm1 Output If InStr strCommand lt gt 0 Then True Then False 9600 0 7 1 strCommand amp Term While ZeroCount lt 20 And strHold lt gt Chr 10 If frmSerial MSComml InBufferCount frmSerial Timerl Enable Do DoEvents Loop Until frmSerial Timerl Enabled d 0 Then True InStr strReturn strReturn ZeroCount ZeroCount
279. strument A customer supplied computer with similarly configured interface port is required to enable communication 6 2 1 Physical Connection The Model 331 has a 9 pin D Subminiature plug on the rear panel for serial communication The original RS 232C standard specifies 25 pins but both 9 and 25 pin connectors are commonly used in the computer industry Many third party cables exist for connecting the instrument to computers with either 9 or 25 pin connectors Paragraph 8 4 1 gives the most common pin assignments for 9 and 25 pin connectors Please note that not all pins or functions are supported by the Model 331 The instrument serial connector is the plug half of a mating pair and must be matched with a socket on the cable If a cable has the correct wiring configuration but also has a plug end a gender changer can be used to mate two plug ends together The letters DTE near the interface connector stand for Data Terminal Equipment and indicate the pin connection of the directional pins such as transmit data TD and receive data RD Equipment with Data Communications Equipment DCE wiring can be connected to the instrument with a straight through cable As an example Pin 3 of the DTE connector holds the transmit line and Pin 3 of the DCE connector holds the receive line so the functions complement It is likely both pieces of equipment are wired in the DTE configuration In this case Pin 3 on one DTE connector used for transmit
280. suring a sensor Four Lead Platinum Four Lead In a four lead measurement current leads and voltage leads are run separately up to the sensor With separate leads there is little current in the voltage leads so their resistance does not enter into the measurement Resistance in the current leads will not change the measurement as long as the voltage compliance of the current source is not reached When two lead sensors are used in four lead measurements the short leads on the sensor have an insignificant resistance Two Lead Sensor Measurement There are times when crowding in a cryogenic system forces users to read sensors in a two lead configuration because there are not enough feedthroughs or room for lead wires If this is the case plus voltage to plus current and minus voltage to minus current leads are attached at the back of the instrument or at the vacuum feedthrough ie Two Lead Diod iode y The error in a resistive measurement is the resistance of the lead wire run with current and voltage together If the leads contribute 2 or 3 Q to a 10 KQ reading the error can probably be tolerated When measuring voltage for diode sensors the error in voltage can be calculated as the lead resistance times the current typically 10 pA For example a 10 Q lead resistance times 10 pA results in a 0 1 mV error in voltage Given the sensitivity of a silicon diode at 4 2 K the error in temperature would be only 3 mK At 77
281. t in kelvin lt coefficient gt Specifies the curves temperature coefficient Valid entries 1 negative 2 positive Configures the user curve header CRVHDR 21 DT 470 00011134 2 325 0 1 term Configures User Curve 21 with a name of DT 470 serial number of 00011134 data format of volts versus kelvin upper temperature limit of 325 K and negative coefficient CRVHDR Curve Header Query Input Format Returned Format CRVPT Input Format Remarks Example CRVPT Input Format Returned Format Remarks CRVHDR lt curve gt term nn lt curve gt Valid entries 1 41 lt name gt lt SN gt lt format gt lt limit value gt lt coefficient gt term aaaaaaaaaaaaaaa aaaaaaaaaa n tnnn nnn n Refer to command for description Curve Data Point Command CRVPT lt curve gt lt index gt lt units value gt temp value gt term nn nnn nnnnnnn tnnnnnnn lt curve gt Specifies which curve to configure Valid entries 21 41 lt index gt Specifies the points index in the curve Valid entries 1 200 lt units value gt Specifies sensor units for this point to 6 digits lt temp value gt Specifies the corresponding temperature in kelvin for this point to 6 digits Configures a user curve data point CRVPT 21 2 0 10191 470 000 N term Sets User Curve 21 second data point to 0 10191 sensor units and 470 000 K Curve Data Point Query CRVPT lt curve gt lt index gt term nn nn
282. tent heat of vaporization 160 kilojoules per liter Liquid density 0 81 kilograms per liter EPA Hazard Categories Immediate Acute Health and Sudden Release of Pressure Hazards DOT Name Nitrogen Refrigerated Liquid DOT Label Nonflammable Gas DOT Class Nonflammable Gas DOT ID No UN 1977 load regulation A steady state decrease of the value of the specified variable resulting from a specified increase in load generally from no load to full load unless otherwise specified M Symbol for magnetization See magnetization magnetic air gap The air space or non magnetic portion of a magnetic circuit magnetic field strength H The magnetizing force generated by currents and magnetic poles For most applications the magnetic field strength can be thought of as the applied field generated for example by a superconducting magnet The magnetic field strength is not a property of materials Measure in Sl units of A m or cgs units of oersted magnetic flux density B Also referred to as magnetic induction This is the net magnetic response of a medium to an applied field H The relationship is given by the following equation B Uo H M for SI and B H 47M for cgs where H magnetic field strength M magnetization and Uo permeability of free space 41 x 10 Him magnetic hysteresis The property of a magnetic material where the magnetic induction B for a given magnetic field strength H depends upon the past history o
283. ter Range Query RANGE term lt range gt term n Refer to command for description Input Reading Status Query RDGST lt input gt term a lt input gt Specifies which input to query A or B lt status bit weighting gt term nnn The integer returned represents the sum of the bit weighting of the input status flag bits A 000 response indicates a valid reading is present Bit Bit Weighting Status Indicator 0 1 invalid reading 4 16 temp underrange 5 32 temp overrange 6 64 sensor units zero 7 128 sensor units overrange Relay Control Parameter Command RELAY lt relay number gt lt mode gt lt input alarm gt lt alarm type gt term n n a n lt relaynumber gt Specifies which relay to configure 1 or 2 lt mode gt Specifies relay mode 0 Off 1 On 2 Alarms lt input alarm gt Specifies which input alarm activates the relay when the relay is in alarm mode A or B lt alarm type gt Specifies the input alarm type that activates the relay when the relay is in alarm mode 0 Low alarm 1 High Alarm 2 Both Alarms RELAY 1 2 B 0 term Relay 1 activates when Input B low alarm activates Relay Control Parameter Query RELAY lt relay number gt term n lt relay number gt Specifies which relay to query 1 or 2 n a n Refer to command for description RELAYST Relay Status Query Input Format Returned Format RELAYST lt high low gt n lt high low gt Specifies relay
284. ter a query is sent A response string is the instruments response or answer to a query string The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in Paragraph 6 3 The response is sent as soon as possible after the instrument receives the query Typically it takes 10 ms for the instrument to begin the response Some responses take longer Remote Operation 6 15 6 2 5 6 2 6 Lake Shore Model 331 Temperature Controller User s Manual Message Flow Control It is important to remember that the user program is in charge of the serial communication at all times The instrument can not initiate communication determine which device should be transmitting at a given time or guarantee timing between messages All of this is the responsibility of the user program When issuing commands only the user program should e Properly format and transmit the command including terminators as one string e Guarantee that no other communication is started for 50 ms after the last character is transmitted e Not initiate communication more than 20 times per second When issuing queries or queries and commands together the user program should e Properly format and transmit the query including terminators as one string e Prepare to receive a response immediately e Receive the entire response f
285. ters AutoTune on the other hand is not able to learn enough about the system to change the control parameters until after the temperature gets near or to the new setpoint Approach to the new setpoint is controlled with the old parameters because they are the best available 2 14 Cooling System Design 3 0 3 1 3 2 Lake Shore Model 331 Temperature Controller User s Manual CHAPTER 3 INSTALLATION GENERAL This chapter provides general installation instructions for the Model 331 Temperature Controller Inspection and unpacking instructions are provided in Paragraph 3 1 Repackaging for shipment instructions are provided in Paragraph 3 2 An definition of rear panel controls is provided in Paragraph 3 3 The rear panel line input assembly is described in Paragraph 3 4 Standard sensor inputs are defined in Paragraph 3 5 Thermocouple sensor installation is described in Paragraph 3 6 Heater output setup is provided in Paragraph 3 7 The analog output and relays of the Model 331S are described in Paragraphs 3 8 and 3 9 respectively An initial setup and system checkout procedure is provided in Paragraph 3 10 For computer interface installation refer to Chapter 6 INSPECTION AND UNPACKING Inspect shipping containers for external damage All claims for damage apparent or concealed or partial loss of shipment must be made in writing to Lake Shore within five 5 days from receipt of goods If damage or loss is apparent please noti
286. th materials that have good conductivity themselves but as sensors heaters sample holders etc are added to an ever more crowded space the junctions between parts are often overlooked In order for control to work well junctions between the elements of the control loop must be in close thermal contact and have good thermal conductivity Gasket materials should always be used along with reasonable pressure Thermal Lag Poor thermal conductivity causes thermal gradients that reduce accuracy and also cause thermal lag that make it difficult for controllers to do their job Thermal lag is the time it takes for a change in heating or cooling power to propagate through the load and get to the feedback sensor Because the feedback sensor is the only thing that lets the controller know what is happening in the system slow information to the sensor slows the response time For example if the temperature at the load drops slightly below the setpoint the controller gradually increases heating power If the feedback information is slow the controller puts too much heat into the system before it is told to reduce heat The excess heat causes a temperature overshoot which degrades control stability The best way to improve thermal lag is to pay close attention to thermal conductivity both in the parts used and their junctions 2 8 Cooling System Design 2 5 3 2 5 4 2 5 5 2 6 Lake Shore Model 331 Temperature Controller User s Manual T
287. tion PC and Interface PC with software loaded which provides serial command line communication Example program in Paragraph 6 2 7 is ideal for this purpose DE 9 to DE 9 cable Pin to pin connections on all 9 pins Female connectors on both ends e DE 9 null modem adapter Test and Measurement Equipment e Digital Multimeter DMM with minimum of 6 digits resolution DMM DC voltage and 4 lead resistance specifications to be equivalent to or better than HP 3458A specifications e Precision reference providing up to 7 5 V with 1 mV resolution for Diode Resistor input calibration e Precision reference providing up to 50 mV with 1 uV resolution for Thermocouple input calibration Calibration Cables e Diode Resistor Calibration Cable 1 required if single or dual Diode Resistor unit L Dual Banana Plugs V 6 Pin DIN 240 Connector Plug e Thermocouple Calibration Cable 1 required if single or dual Thermocouple unit To Voltage Standard Dual Banana 4 Ring Terminals To DMM 8 10 Service Lake Shore Model 331 Temperature Controller User s Manual Equipment Required for Calibration Continued 8 9 2 8 9 2 1 8 9 2 2 Resistor Standards e Resistor standards with the following nominal values If standards are not available Y W 25ppm C metal film resistors can be used They should have connectors attached to mate with two dual banana plugs for 4 lead measurement e 0 short 10 Q 100 Q 500 Q 1kQ 5kQ 1
288. tional system of units SI A universal coherent system of units in which the following seven units are considered basic meter kilogram second ampere kelvin mole and candela The International System of Units or Syst me International d Unit s SI was promulgated in 1960 by the Eleventh General Conference on Weights and Measures For definition spelling and protocols see Reference 3 for a short convenient guide interpolation table A table listing the output and sensitivity of a sensor at regular or defined points which may be different from the points at which calibration data was taken intrinsic coercivity The magnetic field strength H required to reduce the magnetization M or intrinsic induction in a magnetic material to zero intrinsic induction The contribution of the magnetic material B to the total magnetic induction B B B HH SI Bj B H cgs IPTS 68 International Practical Temperature Scale of 1968 Also abbreviated as Tes isolated neutral system A system that has no intentional connection to ground except through indicating measuring or protective devices of very high impedance ITS 90 International Temperature Scale of 1990 Also abbreviated as Too This scale was designed to bring into as close a coincidence with thermodynamic temperatures as the best estimates in 1989 allowed Kelvin K The unit of temperature on the Kelvin Scale It is one of the base units of SI The word degree and its sy
289. to the shield pin of the input connector It should not be terminated at the opposite end of the cable The shield should not be connected to earth ground on the instrument chassis or in the cooling system NOTE The shell of the connector is in contact with the chassis so the cable shield should never touch the outer shell of the connector 3 5 4 Sensor Polarity Lake Shore sensors are shipped with instructions that indicate which sensor leads are which It is important to follow these instructions for plus and minus leads polarity as well as voltage and current when applicable Diode sensors do not operate in the wrong polarity They look like an open circuit to the instrument Two lead resistors can operate with any lead arrangement and the sensor instructions may not specify Four lead resistors can be more dependent on lead arrangement Follow any specified lead assignment for four lead resistors Mixing leads could give a reading that appears correct but is not the most accurate DT 470 SD Diode Sensor Leads Cathode rt tees Anode Installation 3 5 3 5 5 3 5 6 3 5 7 Lake Shore Model 331 Temperature Controller User s Manual Four Lead Sensor Measurement All sensors including both two lead and four lead can be measured with a four lead technique The purpose of a four lead measurement is to eliminate the effect of lead resistance on the measurement If itis not taken out lead resistance is a direct error when mea
290. trol setpoint can be displayed and set in temperature or sensor units Changing setpoint units does not change operation of the controller only the way the setpoint is displayed and entered A valid curve must be assigned to the control input to use temperature units To change setpoint units press the Control Setup key and press Enter until the following display appears Use the A or Y key to cycle through the following setpoint units Temp K Temp C and Sensor where K kelvin C degrees Celsius and Sensor volts V or ohms Q Press the Enter key The Model 331 has two control modes Closed Loop and Open Loop Closed Loop control often called feedback control is described in Paragraph 2 6 of this manual During closed loop control operation the Control Input Setpoint Heater Range PID and Manual Heater Power MHP output parameters are active Open loop control mode allows the user to directly set the heater output for Loop 1 control output for Loop 2 with the MHP Output parameter During Open Loop control only the heater range and MHP Output parameters are active To change Control Mode press the Control Setup key and press Enter until the following display appears The Power Up setting refers to how the control output will respond after the instrument is powered down Power Up Enable means the controller will power up with the control output in the same state it was before power was turned off Power Up D
291. trument will assume the change was intentional and restart the filter Filter window is set in percent of full scale range To configure a filter continue from the Math Setup screen in Paragraph 4 14 press the Enter key until the following display appears E wen Kiem kal uen aia a Te igu Tor Matr H A Use the A or Y key to toggle between Filter On and Off If you select Off the routine will end and return you to the normal display If you select On the routine will continue with the following Use the A or Y key to increment or decrement the Filter Points from 02 thru 64 with 08 being the default Press the Enter key You will see the following display Use the A or Y key to increment or decrement the Filter Window from 01 thru 10 with 01 being the default Press the Enter key You will return to the normal display Operation 4 27 Lake Shore Model 331 Temperature Controller User s Manual 4 15 ALARMS AND RELAYS Model 331S Only 4 15 1 Alarms Each input of the Model 331 has high and low alarm capability for each input Input reading data from any source can be compared to the alarm setpoint values A reading higher than the high setpoint triggers the high alarm for that input A reading lower than the low alarm setpoint triggers the low alarm for that input The Alarm annunciator steadily displays when any alarm is enabled it flashes when any alarm activates An input need
292. ues to factory defaults and resets the instrument The 99 is included to prevent accidentally setting the unit to defaults DISPFLD Displayed Field Command Input DISPFLD lt field gt lt item gt lt source gt term Format n n n lt field gt Specifies field to configure 1 4 lt item gt Specifies item to display in the field 0 Off 1 Input A 2 Input B 3 Setpoint 4 Heater Output lt source gt f Item is 1 or 2 specifies input data to display Valid entries 1 kelvin 2 Celsius 3 sensor units 4 linear data 5 minimum data and 6 maximum data Example DISPFLD 2 1 1 term Displays kelvin reading for Input A in display field 2 DISPFLD Displayed Field Query Input DISPFLD lt field gt term Format n lt field gt Specifies field to query 1 4 Returned lt item gt lt source gt term Format n n Refer to command for description 6 30 Remote Operation EMUL Input Format Remarks EMUL Input Returned Format FILTER Input Format Example FILTER Input Format Returned Format HTR Input Returned Format HTRST Input Returned Format Lake Shore Model 331 Temperature Controller User s Manual 330 Emulation Mode Command EMUL lt off on gt term n lt off on gt Specifies whether 330 Emulation Mode is 0 Off or 1 On Default 0 The 330 Emulation Mode allows the remote interface of the Model 331 to be compatible w
293. umstances should the frozen part be rubbed either before or after rewarming If the eyes are involved flush them thoroughly with warm water for at least 15 minutes In case of massive exposure remove clothing while showering with warm water The patient should not drink alcohol or smoke Keep warm and rest Call a physician immediately C 2 Handling LHe and LN2 Lake Shore Model 331 Temperature Controller User s Manual APPENDIX D CURVE TABLES D1 0 GENERAL Standard curve tables included in the Model 331 Temperature Controller are as follows Curve 01 DT 470 Silicon Diode oooococinnococccccnnccncnccconcnnnos Table D 1 Curve 02 DT 670 Silicon Diode oooooccinnococccccnncoconccconcnnnos Table D 2 Curve 03 amp 04 DT 500 D E1 Silicon Diode sssnesnnnnseeeeeeeee Table D 3 Curve 06 8 07 PT 100 1000 Platinum RTD 0 eeee Table D 4 Curve 08 RXSTOZA RO Mist ii iia Table D 5 Curve 09 RX 202A ROX TEE Table D 6 Curve 12 Type K Thermocouple oocococccccccccccncononcnccnncnnnnnnnos Table D 7 Curve 13 Type E Thermocouple oocococccccccccccnconononccnncnnanannns Table D 8 Curve 14 Type T Thermocouple coooococococccccccccncononcnccnncnnanannos Table D 9 Curve 15 Chromel AuFe 0 03 Thermocouple Table D 10 Curve 16 Chromel AuFe 0 07 Thermocouple Table D 11 Table D 1 Lake Shore DT 470 Silicon Diode Curve 10 ane Temp K Volts Ser Temp K Volts Se Temp K Volt
294. up for at least 30 minutes 10 11 12 13 The default input settings are Silicon Diodes on Inputs A and B with Input A controlling using the Curve 01 DT 470 These settings can be verified by pressing the Input Setup key and following the instructions in Paragraph 4 4 The default control mode is Manual PID where the Proportional Integral and Derivative PID settings are entered by the user The default settings are P 50 20 and D 0 These settings can be verified and or adjusted by pressing the PID MHP key and following the instructions in Paragraph 4 8 For an experiment running at liquid nitrogen temperature a setpoint of 77 K is good for testing purposes Press the Setpoint key Press the 7 key twice then press the Enter key Details of setpoint setting are discussed in Paragraph 4 11 E naang sonny nonga fren See nn wf Ki vi Gei D pros Ei The default setting for the heater is Off To turn the heater on press the Heater Range key Press the A or Y key until Low is displayed Press the Enter key Depending on your actual setup you may need to apply more current to the heater which is accomplished by selecting either the Med or High range Details of heater settings are discussed in Paragraph 4 13 a A i ei CD IT m rm NOTE If any problems appear immediately press the Heater Off key If any error messages are d
295. urn a string identifying itself RESPONSE LSCI MODEL331S8 123456 020300 term ENTER COMMAND KRDG Temperature reading in kelvin query Instrument will return a string with the present temperature reading RESPONSE 273 15 term ENTER COMMAND RANGE 0 Heater range command Instrument will turn off the heater No response will be sent ENTER COMMAND RANGE Heater range query Instrument will return a string with the present heater range setting RESPONSE 0 term ENTER COMMAND RANGE 1 RANGE Heater range command followed by a query Instrument will change to heater Low setting then return a string RESPONSE 1 term with the present setting The following are additional notes on using either IEEE 488 Interface program H you enter a correctly spelled query without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries and should have a space separating the command and associated parameters e Leading zeros and zeros following a decimal point are not needed in a command string but are sent in response to a query A leading is not required but a leading is required 6 1 5 Troubleshooting New Installation 1 Check instrument address 2 Always send terminators 3 Send entire message string at one time including terminators 4 Send only one simple command at a time until communication is established 5 Be sure to spell commands correctly and u
296. use fire flood or acts of God or from failure to properly install operate or maintain the product in accordance with the printed instruction provided 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 Lake Shore 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 Institute of Standards and Technology NIST formerly known as the National Bureau of Standards NBS FIRMWARE LIMITATIONS Lake Shore has worked to ensure that the Model 331 firmware is as free of errors as possible and that the results you obtain from the instrument are accurate and reliable However as with any computer based software the possibility of errors exists In any important research as when using any laboratory equipment results should be carefully examined and rechecked before final conclusions are drawn Neither Lake Shore nor anyone else involved in the creation or production of this firmware can pay for loss of time incon
297. ut Query HTR term lt heater value gt term nnn n lt heater value gt Loop 1 heater output in percent Use AOUT for Loop 2 Heater Status Query HTRST term lt error code gt term n lt error code gt Heater error code 0 no error 1 heater open load 2 heater short Remote Operation 6 31 Lake Shore Model 331 Temperature Controller User s Manual IEEE IEEE 488 Interface Parameter Command Input IEEE lt terminator gt lt EOI enable gt lt address gt term Format n n nn lt terminator gt Specifies the terminator Valid entries 0 lt CR gt lt LF gt 1 lt LF gt lt CR gt 2 lt LF gt 3 no terminator must have EOI enabled lt EOI enable gt Sets EOI mode 0 enabled 1 disabled lt address gt Specifies the IEEE address 1 30 Address 0 and 31 are reserved Example IEEE 0 0 4 term After receipt of the current terminator the instrument uses EOI mode uses lt CR gt lt LF gt as the new terminator and responds to address 4 IEEE IEEE 488 Interface Parameter Query Input IEEE term Returned lt terminator gt lt EOI enable gt lt address gt term Format n n nn Refer to command for description INCRV Input Curve Number Command Input INCRV lt input gt lt curve number gt term Format a nn lt input gt Specifies which input to configure A or B lt curve number gt Specifies which curve the input uses If specified curve parameters do not match the input the
298. uter which tells the Model 331 which functions to perform Below are Model 331 IEEE 488 interface capabilities e SH1 Source handshake capability e RL1 Complete remote local capability e DC1 Full device clear capability e DTO No device trigger capability e CO No system controller capability e T5 Basic TALKER serial poll capability talk only unaddressed to talk if addressed to listen s L4 Basic LISTENER unaddressed to listen if addressed to talk e SR1 Service request capability e AH1 Acceptor handshake capability e PPO No parallel poll capability e El Open collector electronics NOTE The Model 331 IEEE 488 Interface requires that repeat addressing be enabled on the bus controller Instruments are connected to the IEEE 488 bus by a 24 conductor connector cable as specified by the standard Refer to Paragraph 8 4 2 Cables can be purchased from Lake Shore or other electronic suppliers A connector extender Model 4005 is required to use the IEEE 488 Interface and the RELAY and ANALOG OUTPUT Terminal Block at the same time Cable lengths are limited to 2 meters for each device and 20 meters for the entire bus The Model 331 can drive a bus with up to 10 loads If more instruments or cable length is required a bus expander must be used Remote Operation 6 1 Lake Shore Model 331 Temperature Controller User s Manual 6 1 2 1 Changing IEEE 488 Interface Parameters Two interface parameters address and
299. uter interface cables e Leave no unused or unterminated cables attached to the instrument e Make cable runs as short and direct as possible Higher radiated emissions is possible with long cables e Do not tightly bundle cables that carry different types of signals Lake Shore Model 331 Temperature Controller User s Manual TABLE OF CONTENTS Chapter Paragraph Title Page Ti INTRODUCTION actina reegelen ee ee deele Ee 1 1 1 0 GENERAL oi A A elie 1 1 1 1 PRODUCT DESCRIPTION siet shootecs insanin aat chevu shoe savbvb t rianas edeauhens EE enake ERC 1 2 1 2 SENSOR SELECTION GUIDE aripa t A ap Add Eder devisees 1 4 1 3 SPECIFICATIONS geed A EERSTEN AS 1 7 1 4 SAFETY SUMMARY coito airoso dad peewee ceuashipeewnadeess 1 9 1 5 SAFETY SYMBOLS 0 ad 1 10 2 COOLING SYSTEM DESIGN TEE 2 1 2 0 GENERAL ces sscctesasscoepesauas evs gob cs aa ria 2 1 2 1 TEMPERATURE SENSOR SELECTION AA 2 1 2 1 1 TEMpe ature RANGE iii A AE 2 1 2 1 2 ee Er EE 2 1 2 1 3 Environmental Conditions 2 2 2 1 4 Measurement Accuracy ccccccceecceececeeeceeeeeaeeeceeeeeeeaaeaeeeeeeeecaceaaaeeeceeecaeaaaeaeceeeeeeceaeeeeeeseeeneaees 2 2 2 1 5 Sensor PACKAGE EE 2 2 2 2 CALIBRATED SENSORS etii ine inon ia i a aiie eaa eiieeii i e aaae 2 2 2 2 1 Traditional Calibration MEET 2 2 2 2 2 DOM A E E E E E SES E T 2 3 2 2 3 Standard eer 2 3 2 2 4 CalC rve M airgid ada 2 3 2 3 SENSORINSTALLATION 00 a ie 25 2 3 1 Mounting E EE 2 5 2 3 2 Sensor Locations viciado 2 5 2 3 3 The
300. uter interfaces provided with the Model 331 permit remote operation The first is the IEEE 488 Interface described in Paragraph 6 1 The second is the Serial Interface described in Paragraph 6 2 The two interfaces share a common set of commands detailed in Paragraph 6 3 Only one of the interfaces can be used at a time NOTE The remote interface of the Model 331 can be set to emulate a Lake Shore Model 330 Temperature Controller Refer to Paragraph 4 20 to select 330 Emulation Mode Refer to your Model 330 User s Manual for command syntax The following Model 330 commands are not supported in 330 Emulation Mode CUID CURV CURV ECUR KCUR and SCAL IEEE 488 INTERFACE Model 331S Only The IEEE 488 Interface is an instrumentation bus with hardware and programming standards that simplify instrument interfacing The Model 331 IEEE 488 Interface complies with the IEEE 488 2 1987 standard and incorporates its functional electrical and mechanical specifications unless otherwise specified in this manual All instruments on the interface bus 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 Model 331 performs the functions of TALKER and LISTENER but cannot be aBUS CONTROLLER The BUS CONTROLLER is the digital comp
301. ve Temperature limits Power up heater off Short circuit protection Loop 1 Loop 2 Heater Output Type Variable DC current source Variable DC voltage source Heater Output D A Resolution 18 bit 16 bit Max Heater Power 50 W 1 WW Max Heater Output Current 1A 0 1A Heater Output Compliance 50 V 10 V Heater Output Ranges 3 decade steps in power 1 Heater Load Type Resistive Resistive Heater Load Range 10 Q to 100 Q recommended 100 Q minimum Heater Load for Max Power 50 Q 100 Q Heater Noise lt 1 kHz RMS 50 uV 0 017 of output voltage lt 0 3 mV Isolation Optical isolation between output and None other circuits Heater Connector Dual banana Detachable terminal block Introduction 1 7 Lake Shore Model 331 Temperature Controller User s Manual Specifications Continued Loop 1 Full Scale Heater Power at Typical Resistance Heater Resistance Heater Range Heater Power Low 100 mw 100 Med 1W High 10 W Low 250 mW 250 Med 2 5 W High 25 W Low 500 mW 50 Q Med 5W High 50 W Front Panel Display Number of reading displays Display Units Display Source Display Update Rate Temperature Display Resolution Sensor Units Display Resolution Other Displays Setpoint Setting Resolution Heater Output Display Heater Output Resolution Display Annunciators Keypad Front Panel Features Interface 2 line by 20 character 9 mm character height vacuum fluorescent display 1 to 4 K
302. vel but so does the self heating and the associated temperature measurement error sensitivity The ratio of the response or change induced in the output to a stimulus or change in the input Temperature sensitivity of a resistance temperature detector is expressed as S dR dT setpoint The value selected to be maintained by an automatic controller serial interface A computer interface where information is transferred one bit at a time rather than one byte character at a time as in a parallel interface RS 232C is the most common serial interface SI Syst me International d Unit s See International System of Units silicon diode Temperature sensor based on the forward voltage drop at constant current through a pn semiconductor junction formed in crystalline silicon SoftCal In Lake Shore instruments SoftCal is used to improve the accuracy of a DT 400 Series Silicon Temperature Diode Sensor This reduces the error between the sensor and the Standard Curve 10 used by the instrument to convert input voltage from the diode to a corresponding temperature stability The ability of an instrument or sensor to maintain a constant output given a constant input strain relief A predetermined amount of slack to relieve tension in component or lead wires Also called stress relief superconducting magnet An electromagnet whose coils are made of a type Il superconductor with a high transition temperature and extremely high critical field
303. venience loss of use of the product or property damage caused by this product or its failure to work or any other incidental or consequential damages Use of our product implies that you understand the Lake Shore license agreement and statement of limited warranty FIRMWARE LICENSE AGREEMENT The firmware in this instrument is protected by United States copyright law and international treaty provisions To maintain the warranty the code contained in the firmware must not be modified Any changes made to the code is at the user s risk Lake Shore will assume no responsibility for damage or errors incurred as result of any changes made to the firmware Under the terms of this agreement you may only use the Model 331 firmware as physically installed in the instrument Archival copies are strictly forbidden You may not decompile disassemble or reverse engineer the firmware If you suspect there are problems with the firmware return the instrument to Lake Shore for repair under the terms of the Limited Warranty specified above Any unauthorized duplication or use of the Model 331 firmware in whole or in part in print or in any other storage and retrieval system is forbidden TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distinguish their products as trademarks Where those designations appear _in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or
304. w Med High Zone 09 Setpoint Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Heater Range Off Low Med High Zone 08 SS etpont Proportional Integral Derivative MHP Output Heater R 0 1 1000 0 1 1000 0 200 0 100 SSES Off Low Med High Zone 07 _ Setpo int Proportional Integral Derivative MHP Output Heater Rande 0 1 1000 0 1 1000 0 200 0 100 9 Off Low Med High Zone 06 E D lDOlT Proportional Integral Derivative MHP Output Heater Range 0 1 1000 0 1 1000 0 200 0 100 9 Off Low Med High Zone 05 at Setpoint Proportional Integral Derivative MHP Output Heater Ranas 0 1 1000 0 1 1000 0 200 0 100 g Off Low Med High Zone 04 Setpoint Proportional Integral Derivative MHP Output Heater Range 0 1 1000 0 1 1000 0 200 0 100 g Off Low Med High Zone 03 AS oq 17N a Setpoint Proportional Integral Derivative MHP Output Heater manne 0 1 1000 0 1 1000 0 200 0 100 g Off Low Med High Zone 02 A Setpoint Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Heater Range Off Low Med High Zone 01 SS etpoint Proportional Integral Derivative MHP Output eater Bande 0 1 1000 0 1 1000 0 200 0 100 g Off Low Med High Dk gt gt gt HK C331 4 4 eps Figure 4 4 Record of Z
305. ways include the Select for AW display a sample of which is shown below p A Fe KL mn vs n vr A enk fin K Data Entry Allows the user to enter number data using the data entry keys Data entry keys include the numbers 0 9 and decimal point Proportional control parameter is an example of a parameter that requires data entry During a data entry sequence use the data entry keys to enter the number value press the Enter key to accept the new data and advance to the next setting Press the Escape key once to clear the entry twice to return to the normal display Most data entry operations are combined with other settings and grouped under a function key Temperature or sensor unit parameters have the same setting resolution as the display resolution for their corresponding readings Data entry always includes the Enter for display a sample of which is shown below Operation 4 3 4 2 Lake Shore Model 331 Temperature Controller User s Manual Display Definition In normal operation the 2 row by 20 character vacuum fluorescent display is divided into four user configurable areas that can provide temperature readings setpoint display and heater status Other information is displayed when using the various functions on the keypad See Figure 4 2 Display Location 1 Display Location 2 Input A Source Input A Source Input B K Kelvin Input B Same choices as None N
306. ways preserved NOTE The copy routine allows you to overwrite an existing user curve Please ensure the curve number you are writing to is correct before proceeding with curve copy To copy a curve press the Curve Entry key Press the A or Y key until you see the following display Wb dr Press the Enter key You can press the Escape key anytime during this routine to return to the normal display emm Use the A or Y key to select the curve number 01 thru 41 to copy from 5 6 Advanced Operation Lake Shore Model 331 Temperature Controller User s Manual Copy Curve Continued Once the curve number is selected press the Enter key You will see the following message L BR dl 1 Use the A or Y key to select the curve number 21 thru 41 to copy to Press the Enter key to copy the curve You now return to the normal display 5 3 SOFTCAL The Model 331 allows the user to perform inexpensive sensor calibrations with a set of algorithms called SoftCal The two SoftCal algorithms in the Model 331 work with DT 400 Series Silicon Diode sensors and Platinum Sensors They create a new temperature response curve from the standard curve and known data points entered by the user The new curve loads into one of the user curve locations 21 thru 41 in the instrument The following paragraphs describe the data points needed from the user and the expected accuracy of the resulting curv
307. wo Sensor Approach There is a conflict between the best sensor location for measurement accuracy and the best sensor location for control For measurement accuracy the sensor should be very near the sample being measured which is away from the heating and cooling sources to reduce heat flow across the sample and thermal gradients The best control stability is achieved when the feedback sensor is near both the heater and cooling source to reduce thermal lag If both control stability and measurement accuracy are critical it may be necessary to use two sensors one for each function Many temperature controllers including the Model 331 have two sensor inputs for this reason Thermal Mass Cryogenic designers understandably want to keep the thermal mass of the load as small as possible so the system can cool quickly and improve cycle time Small mass can also have the advantage of reduced thermal gradients Controlling a very small mass is difficult because there is no buffer to adsorb small changes in the system Without buffering small disturbances can very quickly create large temperature changes In some systems it is necessary to add a small amount of thermal mass such as a copper block in order to improve control stability System Nonlinearity Because of nonlinearities in the control system a system controlling well at one temperature may not control well at another temperature While nonlinearities exist in all temperature control systems the
308. x where a is the i fit coefficient and x is some function of the dependent variable positive temperature coefficient PTC Refers to the sign of the temperature sensitivity For example the resistance of a PTC sensor increases with increasing temperature pounds per square inch psi A unit of pressure 1 psi 6 89473 kPa Variations include psi absolute psia measured relative to vacuum zero pressure where one atmosphere pressure equals 14 696 psia and psi gauge psig where gauge measured relative to atmospheric or some other reference pressure ppm Parts per million e g 4 x 10 is four parts per million precision Careful measurement under controlled conditions which can be repeated with similar results See repeatability Also means that small differences can be detected and measured with confidence See resolution prefixes Sl prefixes used throughout this manual are as follows Factor Prefix Symbol Factor Prefix Symbol 107 yotta Y 10 deci d 107 zetta Z 10 centi c 10 exa E 10 milli m 10 peta P 105 micro u 107 tera T 107 nano n 10 giga G 10 i pico p 10 mega M 10 femto f 10 kilo k 1078 atto a 10 hecto h 10 zepto E 10 deka da 10 yocto y probe A long thin body containing a sensing element which can be inserted into a system in order to make measurements Typically the measurement is localized to the region near the tip of the probe proportional integral derivative PID A control function where
309. y are most evident at cryogenic temperatures When the operating temperature changes the behavior of the control loop the controller must be retuned As an example a thermal mass acts differently at different temperatures The specific heat of the load material is a major factor in thermal mass and the specific heat of materials like copper change as much as three orders of magnitude when cooled from 100 K to 10 K Changes in cooling power and sensor sensitivity are also sources of nonlinearity The cooling power of most cooling sources also changes with load temperature This is very important when operating at temperatures near the highest or lowest temperature that a system can reach Nonlinearities within a few degrees of these high and low temperatures make it very difficult to configure them for stable control If difficulty is encountered it is recommended to gain experience with the system at temperatures several degrees away from the limit and gradually approach it in small steps Keep an eye on temperature sensitivity Sensitivity not only affects control stability but it also contributes to the overall control system gain The large changes in sensitivity that make some sensors so useful may make it necessary to retune the control loop more often PID CONTROL For closed loop operation the Model 331 temperature controller uses a algorithm called PID control The control equation for the PID algorithm has three variable terms proportiona
310. y consistency allowing the grease to form a cushion between mating surfaces Melting point is 316 K 43 C Can be removed using Xylene with an Isopropyl alcohol rinse 25 Q Cartridge Heater The heater features precision wound nickel chromium resistance wire magnesium oxide insulation two solid pins non magnetic package and has UL and HTR 25 CSA component recognition The heater is 25 W 6 35 mm 0 25 inch diameter by 25 4 mm 1 inch long The 25 W rating is in dead air With proper heat sinking the cartridge heater can handle many times this dead air power rating 50 Q Cartridge Heater The heater features precision wound nickel chromium resistance wire magnesium oxide insulation two solid pins non magnetic package and has UL and HTR 50 CSA component recognition The heater is 50 W 6 35 mm 0 25 inch diameter by 25 4 mm 1 inch long The 50 W rating is in dead air With proper heat sinking the cartridge heater can handle many times this dead air power rating MAN 331 Model 331 Temperature Controller User s Manual Half Rack Mounting Kit for One Model 331 Temperature Controller Half length RM 1 2 mounting panel and mounting ears to attach one Model 331 to a 483 mm 19 inch rack mount space See Figure 7 3 Dual Mounting Shelf for Two Model 331 Temperature Controllers Mounting shelf to attach any two 5 25 inch tall half rack instruments side by side on a 483 mm 19 inch rack mount shelf See Figure 7 4 IMI
311. y to cycle between Input A Input B or None For this example select Input A then press the Enter key You will see the following display Use the A or Y key to cycle through the following data sources Temp K Temp C Sensor Linear Min and Max For this example select Temp K then press the Enter key NOTE The sensor reading of the instrument can always be displayed in sensor units If a temperature response curve is selected for an input its readings may also be displayed in temperature Operation 4 5 Lake Shore Model 331 Temperature Controller User s Manual Display Format Continued With the settings from the previous example Display Location 1 will resemble the following De CA The process is the same for the other three display locations However additional choices are provided for Display Location 3 and 4 being Setpoint and Heater Out respectively In the following example we will setup Display Location 3 to show the setpoint Press the Display Format key hr dr Use the A or W key to increment or decrement through Display Locations 1 thru 4 For this example select Display Location 3 then press the Enter key You will see the following display pii Pa Use the A or Y key to cycle between Input A Input B Setpoint or None For this example select Setpoint then press the Enter key With the settings from the previous example and assuming you s
312. ysicist hazard communication standard HCS The OSHA standard cited in 29 CFR 1910 1200 requiring communication of risks from hazardous substances to workers in regulated facilities hertz Hz A unit of frequency equal to one cycle per second hysteresis The dependence of the state of a system on its previous history generally in the form of a lagging of a physical effect behind its cause Also see magnetic hysteresis 1 D Inner diameter IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronics Engineers IEEE 488 An instrumentation bus with hardware and programming standards designed to simplify instrument interfacing The addressable parallel bus specification is defined by the IEEE initial permeability The permeability determined at H 0 and B 0 initial susceptibility The susceptibility determined at H 0 and M 0 infrared IR For practical purposes any radiant energy within the wavelength range 770 to 10 nanometers is considered infrared energy The full range is usually divided into three sub ranges near IR far IR and sub millimeter input card Electronics on a printed circuit board card that plug into an instrument main frame Used by configurable instruments to allow for different sensor types or interface options interchangeability Ability to exchange one sensor or device with another of the same type without a significant change in output or response interna

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