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Lakeshore 325 User Manual

Other manuals for 325: User Manual

Summary of 325

  • Page 1

    Revision: 1.5 p/n 119-041 12 november 2013 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 disclose...

  • Page 2

    Lake shore model 335 temperature controller user’s manual limited warranty statement warranty period: three (3) years 1. Lake shore warrants that products manufactured by lake shore (the "product") will be free from defects in materials and workmanship for three years from the date of purchaser's ph...

  • Page 3

    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...

  • Page 4

    Lake shore model 325 temperature controller user’s manual.

  • Page 5

    Lake shore model 325 temperature controller user’s manual electromagnetic compatibility (emc) for the model 325 temperature controller electromagnetic compatibility (emc) of electronic equipment is a growing concern worldwide. Emissions of and immunity to electromagnetic interference is now part of ...

  • Page 7: Table Of Contents

    Lake shore model 325 temperature controller user’s manual table of contents i table of contents chapter/section title page 1 introduction .................................................................................................................................................... 1-1 1.0 produ...

  • Page 8

    Lake shore model 325 temperature controller user’s manual ii table of contents table of contents (continued) chapter/section title page 3 installation ........................................................................................................................................................

  • Page 9

    Lake shore model 325 temperature controller user’s manual table of contents iii table of contents (continued) chapter/section title page 4.6 temperature control ........................................................................................................... 4-13 4.6.1 control loops .........

  • Page 10

    Lake shore model 325 temperature controller user’s manual iv table of contents table of contents (continued) chapter/section title page 6.2 serial interface overview .................................................................................................. 6-15 6.2.1 physical connection .......

  • Page 11: List Of Illustrations

    Lake shore model 325 temperature controller user’s manual table of contents v list of illustrations figure no. Title page 1-1 model 325 front view .................................................................................................................................. 1-1 1-2 model 325 rear...

  • Page 12: List Of Tables

    Lake shore model 325 temperature controller user’s manual vi table of contents list of tables table no. Title page 1-1 sensor temperature range ......................................................................................................................... 1-4 1-2 typical sensor performance...

  • Page 13: Chapter 1

    Lake shore model 325 temperature controller user’s manual introduction 1-1 chapter 1 introduction 1.0 product description the model 325 dual-channel temperature controller is capable of supporting nearly any diode, rtd, or thermocouple temperature sensor. Two independent pid control loops with heate...

  • Page 14

    Lake shore model 325 temperature controller user’s manual 1-2 introduction product description (continued) temperature control the model 325 temperature controller offers two independent proportional-integral-derivative (pid) control loops. A pid algorithm calculates control output based on temperat...

  • Page 15

    Lake shore model 325 temperature controller user’s manual introduction 1-3 configurable display the model 325 offers a bright, easy to read oled display that simultaneously displays up to four readings. Display data includes input and source annunciators for each reading. All four display locations ...

  • Page 16

    Lake shore model 325 temperature controller user’s manual 1-4 introduction 1.1 sensor selection table 1-1. Sensor temperature range model useful range magnetic field use diodes silicon diode dt-670-sd 1.4 k to 500 k t 60 k & b 3 t silicon diode dt-670e-br 30 k to 500 k t 60 k & b 3 t silicon diode d...

  • Page 17

    Lake shore model 325 temperature controller user’s manual introduction 1-5 table 1-2. Typical sensor performance example lake shore sensor temp nominal resistance/ voltage typical sensor sensitivity 1 measurement resolution: temperature equivalents electronic accuracy: temperature equivalents temper...

  • Page 18

    Lake shore model 325 temperature controller user’s manual 1-6 introduction 1.2 specifications input specifications sensor temperature coefficient input range excitation current display resolution measurement resolution electronic accuracy (at 25 °c) measurement temperature coefficient electronic con...

  • Page 19

    Lake shore model 325 temperature controller user’s manual introduction 1-7 specifications (continued) control control loops 2 control type closed loop digital pid with manual heater output or open loop tuning autotune (one loop at a time), pid, pid zones control stability sensor dependent, refer to ...

  • Page 20

    Lake shore model 325 temperature controller user’s manual 1-8 introduction specifications (continued) interface ieee-488.2 interface: features sh1, ah1, t5, l4, sr1, rl1, pp0, dc1, dt0, c0, e1 reading rate to 10 rdg/s on each input software support labview™ driver (contact lake shore for availabilit...

  • Page 21

    Lake shore model 325 temperature controller user’s manual introduction 1-9 safety summary (continued) 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...

  • Page 22

    Lake shore model 325 temperature controller user’s manual 1-10 introduction this page intentionally left blank.

  • Page 23: Chapter 2

    Lake shore model 325 temperature controller user’s manual cooling system design 2-1 chapter 2 cooling system design 2.0 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 temper...

  • Page 24

    Lake shore model 325 temperature controller user’s manual 2-2 cooling system design 2.1.4 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 in...

  • Page 25

    Lake shore model 325 temperature controller user’s manual cooling system design 2-3 2.2.3 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 reasonabl...

  • Page 26

    Lake shore model 325 temperature controller user’s manual 2-4 cooling system design 2.2.4 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 325. It can be performed at the facto...

  • Page 27

    Lake shore model 325 temperature controller user’s manual cooling system design 2-5 2.3.5 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 flexi...

  • Page 28

    Lake shore model 325 temperature controller user’s manual 2-6 cooling system design 2.3.7 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 protec...

  • Page 29

    Lake shore model 325 temperature controller user’s manual cooling system design 2-7 2.4.2 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...

  • Page 30

    Lake shore model 325 temperature controller user’s manual 2-8 cooling system design 2.5.4 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 re...

  • Page 31

    Lake shore model 325 temperature controller user’s manual cooling system design 2-9 2.6.2 integral (i) in the control loop, the integral term, also called reset, looks at error over time to build the integral contribution to the output: by adding the integral to proportional contributions, the error...

  • Page 32

    Lake shore model 325 temperature controller user’s manual 2-10 cooling system design p-325-2-3.Bmp figure 2-3. Examples of pid control.

  • Page 33

    Lake shore model 325 temperature controller user’s manual cooling system design 2-11 2.7 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 ba...

  • Page 34

    Lake shore model 325 temperature controller user’s manual 2-12 cooling system design tuning proportional (continued) if the load does 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 se...

  • Page 35

    Lake shore model 325 temperature controller user’s manual cooling system design 2-13 autotuning (continued) when the user selects a new setpoint, the model 325 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 co...

  • Page 36

    Lake shore model 325 temperature controller user’s manual 2-14 cooling system design this page intentionally left blank.

  • Page 37: Chapter 3

    Lake shore model 325 temperature controller user’s manual installation 3-1 chapter 3 installation 3.0 general this chapter provides general installation instructions for the model 325 temperature controller. Please read this entire chapter before installing the instrument and powering it on to ensur...

  • Page 38

    Lake shore model 325 temperature controller user’s manual 3-2 installation 3.2 rear panel definition this section provides a description of the model 325 rear panel connections. The rear panel consists of the line input assembly, rs-232 connector, input a and b sensor input connectors, ieee-488 inte...

  • Page 39

    Lake shore model 325 temperature controller user’s manual installation 3-3 3.3 line input assembly this section describes how to properly connect the model 325 to line power. Please follow these instructions carefully to ensure proper operation of the instrument and the safety of operators. 120 100/...

  • Page 40

    Lake shore model 325 temperature controller user’s manual 3-4 installation 3.4 diode/resistor sensor inputs this section details how to connect diode and resistor sensors to the model 325 inputs. Refer to section 4.4 to configure the inputs. The optional thermocouple input is described in section 3....

  • Page 41

    Lake shore model 325 temperature controller user’s manual installation 3-5 3.4.3 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. Connecting sensor leads to earth grou...

  • Page 42

    Lake shore model 325 temperature controller user’s manual 3-6 installation 3.4.7 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 i...

  • Page 43

    Lake shore model 325 temperature controller user’s manual installation 3-7 3.5.2 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 section 2.3. Cons...

  • Page 44

    Lake shore model 325 temperature controller user’s manual 3-8 installation loop 1 heater output wiring (continued) 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 using a #4 spade, or ring connector. The s...

  • Page 45

    Lake shore model 325 temperature controller user’s manual installation 3-9 boosting output power (continued) 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 ...

  • Page 46

    Lake shore model 325 temperature controller user’s manual 3-10 installation initial setup and system checkout procedure (continued) note: for rated accuracy, the instrument should warm up for at least 30 minutes. 10. The default input settings are “silicon diodes” on inputs a and b, with input a con...

  • Page 47

    Lake shore model 325 temperature controller user’s manual 3-11 this page intentionally left blank.

  • Page 48

    Lake shore model 325 temperature controller user’s manual 3-12 this page intentionally left blank.

  • Page 49: Chapter 4

    Lake shore model 325 temperature controller user’s manual operation 4-1 chapter 4 operation 4.0 general this chapter provides instructions for the general operating features of the model 325 temperature controller. Advanced operation is in chapter 5. Computer interface instructions are in chapter 6....

  • Page 50

    Lake shore model 325 temperature controller user’s manual 4-2 operation keypad definitions (continued) p allows manual adjustment of the proportional control parameter for the currently selected loop. Refer to section 4.8.1. I allows manual adjustment of the integral control parameter for the curren...

  • Page 51

    Lake shore model 325 temperature controller user’s manual operation 4-3 general keypad operation (continued) function key; like heater range. Most are part of a string of settings. Setting selections always include the “select for ... St” display, a sample of which is shown below. Select for disp 1 ...

  • Page 52

    Lake shore model 325 temperature controller user’s manual 4-4 operation 4.2 turning power on after verifying line voltage (section 3.3), 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 en...

  • Page 53

    Lake shore model 325 temperature controller user’s manual operation 4-5 display format and source (units) selection (continued) use the s or t key 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 select for disp...

  • Page 54

    Lake shore model 325 temperature controller user’s manual 4-6 operation 4.4 input setup the model 325 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, ...

  • Page 55

    Lake shore model 325 temperature controller user’s manual operation 4-7 diode sensor input setup – 1 ma excitation current (continued) to access the alternative setup, the diode current must be set to 1 ma. Press and hold the input setup key for 10 seconds to display the screen shown as follows: sel...

  • Page 56

    Lake shore model 325 temperature controller user’s manual 4-8 operation 4.4.3.1 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 n...

  • Page 57

    Lake shore model 325 temperature controller user’s manual operation 4-9 4.4.4.1 room-temperature compensation room-temperature compensation is required to give accurate temperature measurements with thermocouple sensors. It corrects for the temperature difference between the instrument thermal block...

  • Page 58

    Lake shore model 325 temperature controller user’s manual 4-10 operation room-temperature calibration procedure (continued) 7. The current temperature reading is displayed in kelvin. Select for inputa temp 294.15½ enter the true temperature that the thermocouple should read. If input is shorted, the...

  • Page 59

    Lake shore model 325 temperature controller user’s manual operation 4-11 table 4-2. Sensor curves curve number display sensor type model number temperature range for data points, 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...

  • Page 60

    Lake shore model 325 temperature controller user’s manual 4-12 operation 4.5.2 resistor sensor curve selection once the input is setup for the platinum, rhodium-iron, or various ntc rtd sensors (section 4.4.3), you may choose a temperature curve. Standard curve numbers 6 and 7 being relevant to plat...

  • Page 61

    Lake shore model 325 temperature controller user’s manual operation 4-13 filter (continued) use the s or t 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. Select for...

  • Page 62

    Lake shore model 325 temperature controller user’s manual 4-14 operation control loops (continued) table 4-3. Comparison of control loops 1 and 2 feature loop 1 loop 2 maximum output power 25 w 2 w output type current source voltage source multiple output ranges yes no closed loop pid control yes ye...

  • Page 63

    Lake shore model 325 temperature controller user’s manual operation 4-15 4.7 control setup after the input setup has been completed (section 4.4) and loop is selected (section 4.6.1), the user can begin to setup temperature control parameters. Control input is the sensor input that is used for contr...

  • Page 64

    Lake shore model 325 temperature controller user’s manual 4-16 operation control setup (continued) the model 325 will display the heater output as either percent of full scale current or percent of full-scale power for the heater range selected. This parameter affects the heater output display and t...

  • Page 65

    Lake shore model 325 temperature controller user’s manual operation 4-17 4.8.2 manually setting integral (i) the integral parameter (also called reset) is the i part of the pid control equation. It has a range of 0 to 1000 with a resolution of 0.1. Setting i to zero turns the reset function off. The...

  • Page 66

    Lake shore model 325 temperature controller user’s manual 4-18 operation 4.8.4 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 i...

  • Page 67

    Lake shore model 325 temperature controller user’s manual operation 4-19 autotune (continued) once autotune mode is selected, no activity takes place until the setpoint is changed at least 0.5 k. At that time, the control channel annunciator blinks to indicate the instrument is gathering data. This ...

  • Page 68

    Lake shore model 325 temperature controller user’s manual 4-20 operation press the enter key to accept the new upper limit. You will see the next display. Enter for zone 01 prop (p) 50.0 the proportional (p) value is entered using the numeric keypad, which includes the numbers 0 – 9, +/–, and decima...

  • Page 69

    Lake shore model 325 temperature controller user’s manual operation 4-21 c-325-4-4.Bmp figure 4-4. Record of zone settings.

  • Page 70

    Lake shore model 325 temperature controller user’s manual 4-22 operation 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 co...

  • Page 71

    Lake shore model 325 temperature controller user’s manual operation 4-23 4.12 ramp the model 325 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 0 to 100 and a resolution of 0.1. Once the ramp f...

  • Page 72

    Lake shore model 325 temperature controller user’s manual 4-24 operation 4.13 heater range and heater off the heater output for loop 1 is a well-regulated variable dc current source, while the heater output for loop 2 is a variable dc voltage source. Both heater outputs are optically isolated from t...

  • Page 73

    Lake shore model 325 temperature controller user’s manual operation 4-25 4.15 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. Hea...

  • Page 74

    Lake shore model 325 temperature controller user’s manual 4-26 operation interface (continued) to set the ieee-488 interface address and terminators, press the interface key, then press the enter key until you see the following screen. Select with °® ieee address 12 use the s or t key to increment o...

  • Page 75

    Lake shore model 325 temperature controller user’s manual operation 4-27 table 4-4. Default values control setup control input ................... Input a sp units ........................... Temp k control mode .................. Closed power up ......................... Disable setpoint ramp ........

  • Page 76

    Lake shore model 325 temperature controller user’s manual 4-28 operation this page intentionally left blank.

  • Page 77: Chapter 5

    Lake shore model 325 temperature controller user’s manual advanced operation 5-1 chapter 5 advanced operation 5.0 general this chapter provides information on the advanced operation of the model 325 temperature controller. 5.1 curve numbers and storage the model 325 has 20 standard curve locations, ...

  • Page 78

    Lake shore model 325 temperature controller user’s manual 5-2 advanced operation table 5-1. Curve header parameters name: the curve name cannot be changed from the front panel. Curve names can only be entered over the computer interface (up to 15 characters). The default curve name is user xx, where...

  • Page 79

    Lake shore model 325 temperature controller user’s manual advanced operation 5-3 curve breakpoints (continued) 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 prac...

  • Page 80

    Lake shore model 325 temperature controller user’s manual 5-4 advanced operation edit curve (continued) enter for curve 21 serial # 0123456789 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...

  • Page 81

    Lake shore model 325 temperature controller user’s manual advanced operation 5-5 edit curve (continued) 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 zeros for both the sensor reading and tempe...

  • Page 82

    Lake shore model 325 temperature controller user’s manual 5-6 advanced operation 5.2.3 copy curve temperature curves can be copied from one location inside the model 325 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 ...

  • Page 83

    Lake shore model 325 temperature controller user’s manual advanced operation 5-7 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 shor...

  • Page 84

    Lake shore model 325 temperature controller user’s manual 5-8 advanced operation 5.3.3 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 t...

  • Page 85

    Lake shore model 325 temperature controller user’s manual advanced operation 5-9 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 t...

  • Page 86

    Lake shore model 325 temperature controller user’s manual 5-10 advanced operation softcal™ calibration curve creation (continued) 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. Th...

  • Page 87: Chapter 6

    Lake shore model 325 temperature controller user’s manual remote operation 6-1 chapter 6 computer interface operation 6.0 general this chapter provides operational instructions for the computer interface for the lake shore model 325 temperature controller. Either of the two computer interfaces provi...

  • Page 88

    Lake shore model 325 temperature controller user’s manual 6-2 remote operation changing ieee-488 interface parameters (continued) press the s or t keys to increment or decrement the ieee address to the desired number. Valid addresses are 1 through 30. Default is 12. Press enter to accept new number ...

  • Page 89

    Lake shore model 325 temperature controller user’s manual remote operation 6-3 6.1.3.2 common commands common commands are addressed commands that create commonalty between instruments on the bus. All instruments that comply with the ieee-488 1987 standard share these commands and their format. Comm...

  • Page 90

    Lake shore model 325 temperature controller user’s manual 6-4 remote operation 6.1.4.1.3 enable registers each register set includes an enable register as shown in figure 6-1. An enable register determines which bits in the corresponding event register will set the summary bit for the register set i...

  • Page 91

    Lake shore model 325 temperature controller user’s manual remote operation 6-5 6.1.4.1.4 status byte register the status byte register, typically referred to as the status byte, is a non-latching, read-only register that contains all of the summary bits from the register sets. The status of the summ...

  • Page 92

    Lake shore model 325 temperature controller user’s manual 6-6 remote operation 6.1.4.2 status register sets as shown in figure 6-1, there are two register sets in the status system of the model 325: standard event status register and operation event register. 6.1.4.2.1 standard event status register...

  • Page 93

    Lake shore model 325 temperature controller user’s manual remote operation 6-7 figure_6-3.Bmp figure 6-3. Operation event register 6.1.4.3 status byte and service request (srq) as shown in figure 6-1, the status byte register receives the summary bits from the two status register sets and the messag...

  • Page 94

    Lake shore model 325 temperature controller user’s manual 6-8 remote operation 6.1.4.3.2 service request enable register the service request enable register is programmed by the user and determines which summary bits of the status byte may set bit 6 (rqs/mss) to generate a service request. Enable bi...

  • Page 95

    Lake shore model 325 temperature controller user’s manual remote operation 6-9 table 6-3. Programming example to generate an srq command or operation description *esr? Read and clear the standard event status register. *ese 32 enable the command error (cme) bit in the standard event status register ...

  • Page 96

    Lake shore model 325 temperature controller user’s manual 6-10 remote operation 6.1.5 ieee interface example program a visual basic program is included to illustrate the ieee-488 communication functions of the instrument. Instructions for setting up the ieee-488 board is included in section 6.1.5.1....

  • Page 97

    Lake shore model 325 temperature controller user’s manual remote operation 6-11 vb_gpib_1.Bmp figure 6-5. Gpib setting configuration vb_gpib_2.Bmp figure 6-6. Dev 12 device template configuration.

  • Page 98

    Lake shore model 325 temperature controller user’s manual 6-12 remote operation vb_gpib_3.Bmp vb_gpib_4.Bmp visual basic ieee-488 interface program setup (continued) 7. In the properties window, use the dropdown list to select between the different controls of the current project. 8. Set the propert...

  • Page 99

    Lake shore model 325 temperature controller user’s manual remote operation 6-13 table 6-5. Visual basic ieee-488 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 privat...

  • Page 100

    Lake shore model 325 temperature controller user’s manual 6-14 remote operation 6.1.5.3 program operation once the 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]...

  • Page 101

    Lake shore model 325 temperature controller user’s manual remote operation 6-15 table 6-6. Serial interface specifications connector type: connector wiring: voltage levels: transmission distance: timing format: transmission mode: baud rate: handshake: character bits: parity: terminators: command rat...

  • Page 102

    Lake shore model 325 temperature controller user’s manual 6-16 remote operation 6.2.3 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 bi...

  • Page 103

    Lake shore model 325 temperature controller user’s manual remote operation 6-17 vb_serial_1.Bmp 6.2.6 changing baud rate to use the serial interface, you must first set the baud rate. Press interface key to display the following screen. Select-with-°® baud--9600 press the s or t key to cycle through...

  • Page 104

    Lake shore model 325 temperature controller user’s manual 6-18 remote operation vb_serial_2.Bmp table 6-7. Serial interface program control properties current name property new value label1 name caption lblexitprogram type “exit” to end program. Label2 name caption lblcommand command label3 name cap...

  • Page 105

    Lake shore model 325 temperature controller user’s manual remote operation 6-19 table 6-8. 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 ...

  • Page 106

    Lake shore model 325 temperature controller user’s manual 6-20 remote operation 6.2.7.2 program operation once the 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]...

  • Page 107

    Lake shore model 325 temperature controller user’s manual remote operation 6-21 6.3 command summary this section provides a listing of the ieee-488 and serial interface commands. A summary of all the commands is provided in table 6-9. All the commands are detailed in section 6.3.1, which is presente...

  • Page 108

    Lake shore model 325 temperature controller user’s manual 6-22 remote operation table 6-9. Command summary command function page qcls clear interface cmd .............................6-23 qese event status enable cmd .....................6-23 qese? Event status enable query ...................6-23 q...

  • Page 109

    Lake shore model 325 temperature controller user’s manual remote operation 6-23 6.3.1 interface commands (alphabetical listing) qcls clear interface command input: q cls[term] remarks: clears the bits in the status byte register and standard event status register and terminates all pending operation...

  • Page 110

    Lake shore model 325 temperature controller user’s manual 6-24 remote operation q opc operation complete command input: q opc[term] remarks: 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 ...

  • Page 111

    Lake shore model 325 temperature controller user’s manual remote operation 6-25 qtst? Self-test query input: q tst?[term] returned: [term] format: n 0 = no errors found, 1 = errors found remarks: the model 325 reports status based on test done at power up. Qwai wait-to-continue command input: q wai[...

  • Page 112

    Lake shore model 325 temperature controller user’s manual 6-26 remote operation crvhdr curve header command input: crvhdr , , , , , [term] format: nn,aaaaaaaaaaaaaaa,aaaaaaaaaa,n,±nnn.Nnn,n specifies which curve to configure. Valid entries: 21 – 35. Specifies curve name. Limited to 15 characters. Sp...

  • Page 113

    Lake shore model 325 temperature controller user’s manual remote operation 6-27 cset control loop parameter command input: cset , , , , [term] format: n,a,n,n,n specifies which loop to configure: 1 or 2. Specifies which input to control from: a or b. Specifies setpoint units. Valid entries: 1 = kelv...

  • Page 114

    Lake shore model 325 temperature controller user’s manual 6-28 remote operation filter input filter parameter command input: filter , , , [term] format: a,n,nn,nn specifies input to configure: a or b. Specifies whether the filter function is 0 = off or 1 = on. Specifies how many data points the filt...

  • Page 115

    Lake shore model 325 temperature controller user’s manual remote operation 6-29 ieee? Ieee-488 interface parameter query input: ieee?[term] returned: , , [term] format: n,n,nn (refer to command for description) incrv input curve number command input: incrv , [term] format: a,nn specifies which input...

  • Page 116

    Lake shore model 325 temperature controller user’s manual 6-30 remote operation keyst? Last key press query input: keyst?[term] returned: [term] format: nn remarks: returns a number descriptor of the last key pressed since the last keyst?. Returns “21” after initial power-up. Returns “00” if no key ...

  • Page 117

    Lake shore model 325 temperature controller user’s manual remote operation 6-31 mout control loop manual heater power (mhp) output command input: mout , [term] format: n, nnnnnn[term] specifies loop to configure: 1 or 2. Specifies value for manual output. Example: mout 1,22.45[term] – control loop 1...

  • Page 118

    Lake shore model 325 temperature controller user’s manual 6-32 remote operation ramp? Control setpoint ramp parameter query input: ramp? Format: n specifies which loop to query: 1 or 2. Returned: , [term] format: n,±nnnnn (refer to command for description) rampst? Control setpoint ramp status query ...

  • Page 119

    Lake shore model 325 temperature controller user’s manual remote operation 6-33 scal generate softcal curve command input: scal , , , , , , , , [term] format: n,nn,aaaaaaaaaa,±nnnnn,±nnnnn,±nnnnn,±nnnnn,±nnnnn,±nnnnn specifies the standard curve to generate a softcal from. Valid entries: 1, 6, 7. Sp...

  • Page 120

    Lake shore model 325 temperature controller user’s manual 6-34 remote operation temp? Thermocouple junction temperature query input: temp? Returned: [term] format: ±nnnnnnn remarks: temperature is in kelvin. This query returns the temperature of the ceramic thermocouple block used in the room temper...

  • Page 121

    Lake shore model 325 temperature controller user’s manual remote operation 6-35 zone? Control loop zone table parameter query input: zone? , [term] format: n,nn specifies which loop to query: 1 or 2. Specifies which zone in the table to query. Valid entries: 1 – 10. Returned: , , , , , [term] format...

  • Page 122

    Lake shore model 325 temperature controller user’s manual 6-36 remote operation this page intentionally left blank.

  • Page 123: Chapter 7

    Lake shore model 325 temperature controller user’s manual options and accessories 7-1 chapter 7 options and accessories 7.0 general this chapter provides information on the models, options, and accessories available for the model 325 temperature controller. 7.1 models the list of model 325 model num...

  • Page 124

    Lake shore model 325 temperature controller user’s manual 7-2 options and accessories 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 catalog for details. A list of accessor...

  • Page 125

    Lake shore model 325 temperature controller user’s manual options and accessories 7-3 accessories (continued) model description of accessories (continued) htr-25 25 cartridge heater. The heater features precision-wound nickel-chromium resistance wire, magnesium oxide insulation, two solid pins, non-...

  • Page 126

    Lake shore model 325 temperature controller user’s manual 7-4 options and accessories p-325-7-4.Jpg figure 7-2. Model rm-1/2 rack-mount kit.

  • Page 127

    Lake shore model 325 temperature controller user’s manual options and accessories 7-5 c-325-7-5.Bmp figure 7-3. Model rm-2 dual rack-mount shelf.

  • Page 128

    Lake shore model 325 temperature controller user’s manual 7-6 options and accessories.

  • Page 129: Chapter 8

    Lake shore model 325 temperature controller user’s manual service 8-1 chapter 8 service 8.0 general this chapter provides basic service information for the model 325 temperature controller. Customer service of the product is limited to the information presented in this chapter. Factory trained servi...

  • Page 130

    Lake shore model 325 temperature controller user’s manual 8-2 service 8.3 fuse drawer the fuse drawer supplied with the model 325 holds the instrument line fuses and line voltage selection module. The drawer holds two 5 × 20 mm time delay fuses. It requires two good fuses of the same rating to opera...

  • Page 131

    Lake shore model 325 temperature controller user’s manual service 8-3 8.5 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 ...

  • Page 132

    Lake shore model 325 temperature controller user’s manual 8-4 service handling electrostatic discharge sensitive components (continued) 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 el...

  • Page 133

    Lake shore model 325 temperature controller user’s manual service 8-5 c-325-8-4.Bmp pin description 1 2 loop 2 output – hi (+) loop 2 output – lo (–) figure 8-5. Loop 2 heater output terminal block f-325-8-5.Bmp model 325 temperature controller typical computers de-9p (dte) db-25p (dte) de-9p (dte) ...

  • Page 134

    Lake shore model 325 temperature controller user’s manual 8-6 service 8.7.1 serial interface cable wiring the following are suggested cable wiring diagrams for connecting the model 325 serial interface to various customer personal computers (pcs). Model 325 to pc serial interface – pc with de-9p mod...

  • Page 135

    Lake shore model 325 temperature controller user’s manual service 8-7 8.7.2 ieee-488 interface connector connect to the ieee-488 interface connector on the model 325 rear with cables specified in the ieee-488-1978 standard document. The cable has 24 conductors with an outer shield. The connectors ar...

  • Page 136

    Lake shore model 325 temperature controller user’s manual 8-8 service 8.8 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...

  • Page 137

    Lake shore model 325 temperature controller user’s manual service 8-9 8.10 jumpers there are five jumpers located on the main circuit board of the model 325. See figure 8-8 for the location of the jumpers (reference designators jmp1 through jmp5). Caution: only jmp2 and jmp4 should be changed by the...

  • Page 138

    Lake shore model 325 temperature controller user’s manual 8-10 service p-325-8-7.Bmp figure 8-8. Location of internal components.

  • Page 139

    Lake shore model 325 temperature controller user’s manual service 8-11 8.12 calibration procedure the model 325 requires calibration of both of the sensor inputs and loop 2 heater output to operate within specification. None of the other circuits require calibration. The sensor inputs may be configu...

  • Page 140

    Lake shore model 325 temperature controller user’s manual 8-12 service equipment required for calibration (continued) resistor standards • resistor standards with the following nominal values (if standards are not available, 0.25 w 25 ppm/ o c metal film resistors can be used) — they should have con...

  • Page 141

    Lake shore model 325 temperature controller user’s manual service 8-13 8.12.2.3 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 325. Process 1. C...

  • Page 142

    Lake shore model 325 temperature controller user’s manual 8-14 service 8.12.2.4 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 325. This...

  • Page 143

    Lake shore model 325 temperature controller user’s manual service 8-15 table 8-2. Calibration table for resistive ranges range calibration resistor nominal value resistor value known to reversal cal. Command type number 100 plat/250 100 ±0.0070 off 2 100 plat/250 100 ±0.0070 on 10 100 plat/500 500 ±...

  • Page 144

    Lake shore model 325 temperature controller user’s manual 8-16 service thermocouple input ranges calibration (continued) 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: -...

  • Page 145

    Lake shore model 325 temperature controller user’s manual service 8-17 loop 2 voltage output calibration (continued) 3. Set loop 2 output to open loop operation and set manual output of 0%. Read the output voltage with the dmm to a tolerance of ±0.0001 vdc and record as zero offset (zo). 4. Set loop...

  • Page 146

    Lake shore model 325 temperature controller user’s manual 8-18 service calread? Six digit input reading query input: calread? [term] format: a a or b returned: [term] format: ±n.Nnnnn remarks: returns 6-digit value of selected input reading. Used for calz and calg functions. Calsave calibration save...

  • Page 147: Appendix A

    Lake shore model 325 temperature controller user’s manual glossary of terminology a-1 appendix a glossary of terminology absolute zero. The temperature of –273.16 °c, or –459.69 °f, or 0 k, thought to be the temperature at which molecular motion vanishes and a body would have no heat energy. 1 alume...

  • Page 148

    Lake shore model 325 temperature controller user’s manual a-2 glossary of terminology coercive force (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)...

  • Page 149

    Lake shore model 325 temperature controller user’s manual glossary of terminology a-3 gauss (g). The cgs unit for magnetic flux density (b). 1 gauss = 10 –4 tesla. Named for karl fredrich gauss (1777 – 1855) a german mathematician, astronomer, and physicist. Gaussian system (units). A system in whic...

  • Page 150

    Lake shore model 325 temperature controller user’s manual a-4 glossary of terminology liquid nitrogen (ln 2 ). Also used for low temperature and superconductivity research and for its refrigeration properties such as in freezing tissue cultures: minimum purity 99.998%, o 2 8 ppm max. Boiling point a...

  • Page 151

    Lake shore model 325 temperature controller user’s manual glossary of terminology a-5 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 cal...

  • Page 152

    Lake shore model 325 temperature controller user’s manual a-6 glossary of terminology seebeck effect. The development of a voltage due to differences in temperature between two junctions of dissimilar metals in the same circuit. 1 self-heating. Heating of a device due to dissipation of power resulti...

  • Page 153: Appendix B

    Lake shore model 325 temperature controller user’s manual temperature scales b-1 appendix b temperature scales b1.0 definition temperature is a fundamental unit of measurement that describes the kinetic and potential energies of the atoms and molecules of bodies. When the energies and velocities of ...

  • Page 154

    Lake shore model 325 temperature controller user’s manual b-2 temperature scales table b-1. Temperature conversion table °f °c k °f °c k °f °c k -459.67 -273.15 0 -454 -270 3.15 -450 -267.78 5.37 -449.67 -267.59 5.56 -441.67 -263.15 10 -440 -262.22 10.93 -439.67 -262.04 11.11 -436 -260 13.15 -430 -2...

  • Page 155: Appendix C

    Lake shore model 325 temperature controller user’s manual handling lhe and ln 2 c-1 appendix c handling liquid helium and nitrogen c1.0 general use of liquid helium (lhe) and liquid nitrogen (ln 2 ) is often associated with the model 325 temperature controller. Although not explosive, there are a nu...

  • Page 156

    Lake shore model 325 temperature controller user’s manual c-2 handling lhe and ln 2 c4.0 liquid helium and nitrogen safety precautions transferring lhe and ln 2 and operation of the storage dewar controls should be in accordance with the manufacturer/supplier’s instructions. During this transfer, it...

  • Page 157: Appendix D

    Lake shore model 325 temperature controller user’s manual curve tables d-1 appendix d curve tables d1.0 general standard curve tables included in the model 325 temperature controller are as follows: curve 01 dt-470 silicon diode ................................................... Table d-1 curve 02 ...

  • Page 158

    Lake shore model 325 temperature controller user’s manual d-2 curve tables table d-2. Standard dt-670 diode curve breakpoint v temp. (k) breakpoint v temp. (k) breakpoint v temp. (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 0.090570 0.110239 0.136555 0.179181 0.265393 0.3495...

  • Page 159

    Lake shore model 325 temperature controller user’s manual curve tables d-3 table d-4. Lake shore pt-100/-1000 platinum rtd curves break- pt-100 pt-1000 point temp. (k) ohms ( temp. (k) ohms ( 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 030.0 032.0 036.0 038.0 040.0 ...

  • Page 160

    Lake shore model 325 temperature controller user’s manual d-4 curve tables table d-5. Lake shore rx- 102a rox™ curve break- point log temp. (k) break- point log temp. (k) break- point log temp. (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3.0208...

  • Page 161

    Lake shore model 325 temperature controller user’s manual curve tables d-5 table d-6. Lake shore rx- 202a rox™ curve break- point log temp. (k) break- point log temp. (k) break- point log temp. (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 3.35085 3.35...

  • Page 162

    Lake shore model 325 temperature controller user’s manual d-6 curve tables table d-7. Type k (nickel-chromium vs. Nickel-aluminum) thermocouple curve break- point mv temp (k) break- point mv temp (k) break- point mv temp (k) break- point mv temp (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20...

  • Page 163

    Lake shore model 325 temperature controller user’s manual curve tables d-7 table d-8. Type e (nickel-chromium vs. Copper-nickel) thermocouple curve break- point mv temp (k) break- point mv temp (k) break- point mv temp (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29...

  • Page 164

    Lake shore model 325 temperature controller user’s manual d-8 curve tables table d-9. Type t (copper vs. Copper-nickel) thermocouple curve break- point mv temp (k) break- point mv temp (k) break- point mv temp (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32...

  • Page 165

    Lake shore model 325 temperature controller user’s manual curve tables d-9 table d-10. Chromel-aufe0.03% thermocouple curve * breakpoint mv temp (k) breakpoint mv temp (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 -4.6667 -4.62838 -4.60347 -4.58043 -4.53965 ...

  • Page 166

    Lake shore model 325 temperature controller user’s manual d-10 curve tables table d-11. Chromel-aufe0.07% thermocouple curve break- point mv temp (k) break- point mv temp (k) break- point mv temp (k) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 -5.2795...