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Lakeshore 642 User Manual

Manual is about: Electromagnet Power Supply

Summary of 642

  • Page 1

    Revision 1.3 p/n 119-042 9 january 2008 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 a...

  • Page 2

    Lake shore model 642 electromagnet power supply user’s manual ii limited warranty statement warranty period: one (1) year 1. Lake shore warrants that this lake shore product (the “product”) will be free from defects in materials and workmanship for the warranty period specified above (the “warranty ...

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    Lake shore model 642 electromagnet power supply user’s manual iii.

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    Lake shore model 642 electromagnet power supply user’s manual iv this page intentionally left blank.

  • Page 5: Table of Contents

    Lake shore model 642 electromagnet power supply user’s manual table of contents v table of contents chapter/section title page 1 introduction .................................................................................................................................................... 1-1 1.0 g...

  • Page 6

    Lake shore model 642 electromagnet power supply user’s manual vi table of contents table of contents (continued) chapter/section title page 4 operation........................................................................................................................................................

  • Page 7

    Lake shore model 642 electromagnet power supply user’s manual table of contents vii table of contents (continued) chapter/section title page 5.1.4.2 status register sets ...................................................................................................................... 5-8 5.1.4.2...

  • Page 8

    Lake shore model 642 electromagnet power supply user’s manual viii table of contents table of contents (continued) chapter/section title page 7.9 firmware replacement ............................................................................................................... 7-7 7.10 connector an...

  • Page 9: List of Illustrations

    Lake shore model 642 electromagnet power supply user’s manual table of contents ix list of illustrations figure no. Title page 1-1 model 642 front panel ............................................................................................................................. 1-2 2-1 a typical ele...

  • Page 10: List of Tables

    Lake shore model 642 electromagnet power supply user’s manual x table of contents list of tables table no. Title page 3-1 rear panel connector identification ......................................................................................................... 3-2 3-2 voltage and current selectio...

  • Page 11: Chapter 1

    Lake shore model 642 electromagnet power supply user’s manual introduction 1-1 chapter 1 introduction 1.0 general this chapter provides an introduction to the model 642 electromagnet power supply. The model 642 was designed and manufactured in the united states of america by lake shore cryotronics, ...

  • Page 12

    Lake shore model 642 electromagnet power supply user’s manual 1-2 introduction output architecture (continued) the model 642 output architecture relies on low noise, linear input and output stages. The linear circuitry of the model 642 permits operation with less electrical noise than switch-mode el...

  • Page 13

    Lake shore model 642 electromagnet power supply user’s manual introduction 1-3 description (continued) interfaces the model 642 includes ieee-488 and rs-232c interfaces that provide access to operating data, stored parameters, and remote control of all front panel operated functions. A keypad lock-o...

  • Page 14

    Lake shore model 642 electromagnet power supply user’s manual 1-4 introduction specifications (continued) output programming internal current setting resolution 0.1 ma (20 bit) settling time 600 ms for 1% step to within 1 ma (of internal setting) accuracy ±10 ma ±0.05% of setting operation keypad, c...

  • Page 15

    Lake shore model 642 electromagnet power supply user’s manual introduction 1-5 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 software support national instruments labview ™ driver (consult lake shore for ...

  • Page 16

    Lake shore model 642 electromagnet power supply user’s manual 1-6 introduction specifications (continued) general line power power 5500 va max voltage and current 200/208 vac ± 10%, 13 a/phase 220/230 vac ± 10%, 12 a/phase 380 vac ± 10%, 7 a/phase 400/415 vac ± 10%, 6.5 a/phase protection three phas...

  • Page 17

    Lake shore model 642 electromagnet power supply user’s manual introduction 1-7 accessories included man-642 model 642 user manual 6031 two front handles 6032 two rear handles 6051 terminal block, 4 pin 6052 terminal block, 8 pin 6252 15-pin d-sub mating connector, analog i/o 108-654 strain relief bu...

  • Page 18

    Lake shore model 642 electromagnet power supply user’s manual 1-8 introduction safety summary (continued) 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 represe...

  • Page 19

    Lake shore model 642 electromagnet power supply user’s manual introduction 1-9 safety summary (continued) 1.4 safety symbols number symbol 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 none publication description iec 417, no. 5031 direct current iec 417, no. 5032 iec 417, no. 5033 both direct and alternat...

  • Page 20

    Lake shore model 642 electromagnet power supply user’s manual 1-10 introduction this page intentionally left blank.

  • Page 21: Chapter 2

    Lake shore model 642 electromagnet power supply user’s manual magnet system design 2-1 chapter 2 magnet system design, installation, and operation 2.0 general this chapter provides the user insight into the design, installation, and operation of a typical electromagnet. For information on how to ins...

  • Page 22

    Lake shore model 642 electromagnet power supply user’s manual 2-2 magnet system design 2.2 magnet construction the magnet consists of two water-cooled coils surrounding adjustable iron poles, which are fitted into an iron frame. The frame supports the poles and coils, and improves the magnet’s effic...

  • Page 23

    Lake shore model 642 electromagnet power supply user’s manual magnet system design 2-3 power lead power lead cross connection wiring power lead power lead cross connection wiring bolt belleville washer cable connection magnet power lug plain washer nut (parallel wiring) (series wiring) figure 2-3. T...

  • Page 24

    Lake shore model 642 electromagnet power supply user’s manual 2-4 magnet system design 2.3.3 temperature switches and flow switches as discussed in section 2.3.1, water-cooling for the magnet is essential. To protect the magnet from damage resulting from an interruption in cooling water, a flow swit...

  • Page 25

    Lake shore model 642 electromagnet power supply user’s manual magnet system design 2-5 2.3.6 final check-out when all of the connections have been made the system should be tested to be sure it is operating correctly. The settings for the magnet water should be checked to verify that they are correc...

  • Page 26

    Lake shore model 642 electromagnet power supply user’s manual 2-6 magnet system design figure 2-5. Typical curves of field vs. Current for various air gaps and pole cap sizes (sheet 2 of 3).

  • Page 27

    Lake shore model 642 electromagnet power supply user’s manual magnet system design 2-7 figure 2-5. Typical curves of field vs. Current for various air gaps and pole cap sizes (sheet 3 of 3) 2.4.3 operation under field control to obtain a linear field ramp, a magnetic sensor such as a hall probe is p...

  • Page 28

    Lake shore model 642 electromagnet power supply user’s manual 2-8 magnet system design 2.4.4 avoiding cooling water condensation if the temperature of the cooling water is too cool relative to the air temperature and humidity, condensation can occur. Condensation inside the power supply can cause se...

  • Page 29: Chapter 3

    Lake shore model 642 electromagnet power supply user’s manual installation 3-1 chapter 3 installation 3.0 general this chapter provides general installation instructions for the model 642 electromagnet power supply. Caution: to ensure the best possible performance and maintain operator safety, read ...

  • Page 30

    Lake shore model 642 electromagnet power supply user’s manual 3-2 installation 3.2 rear panel definition this paragraph defines the rear panel of the model 642. Refer to table 3-1. Readers are referred to paragraphs that contain installation instructions and connector pin-outs for each feature. Caut...

  • Page 31

    Lake shore model 642 electromagnet power supply user’s manual installation 3-3 1 2 3 12 8 7 6 10 15 9 14 13 15 11 5 4 figure 3-1. Model 642 rear panel (shown with wiring cover removed) 3.3 power wiring and set-up this section describes how to properly connect the model 642 to the line power. Please ...

  • Page 32

    Lake shore model 642 electromagnet power supply user’s manual 3-4 installation line voltage selection (continued) changing line voltage is accomplished by moving four wires to the required voltage terminals. The required location is shown in figure 3-2. To change the voltage setting, loosen the four...

  • Page 33

    Lake shore model 642 electromagnet power supply user’s manual installation 3-5 3.3.3 start-up fuses the start-up transformer and associated circuitry are energized whenever the power is connected. To protect this circuitry, two ¼ a, class cc fuses are provided. A fuse is accessed by pulling open the...

  • Page 34

    Lake shore model 642 electromagnet power supply user’s manual 3-6 installation power cable strip 13mm (0.5 in) wire ferrule (optional) power terminals 140 mm (5.5 in) figure 3-6. Typical power input wiring 3.3.6 wiring cover when the power wiring, voltage setting and current setting are complete, in...

  • Page 35

    Lake shore model 642 electromagnet power supply user’s manual installation 3-7 3.3.7 mains wiring no cord or disconnecting plug is provided with the unit. In all cases, the field connection of the mains wiring shall comply with all local wiring codes where the model 642 is installed. The power sourc...

  • Page 36

    Lake shore model 642 electromagnet power supply user’s manual 3-8 installation 3.6 power supply connector the power supply connector provides terminals for an optional water flow switch and an optional cooling water control solenoid valve. The flow switch must have a normally closed contact rated at...

  • Page 37

    Lake shore model 642 electromagnet power supply user’s manual installation 3-9 solenoid valve with mounting bracket adjustable hose clamp reinforced hose 230 mm (9 in) long figure 3-12. Water valve connection 3.8 magnet cable connections magnet cable connections are made at the output + and – termin...

  • Page 38

    Lake shore model 642 electromagnet power supply user’s manual 3-10 installation belleville washer bolt output lug magnet cable plain washer nut figure 3-13. Output cable connection lug cover 38 mm (1.5 in) mounting screws figure 3-14. Output lug cover installation.

  • Page 39

    Lake shore model 642 electromagnet power supply user’s manual installation 3-11 3.9 analog input/output connections the analog i/o connector provides connections to analog signals used to monitor or control the power supply. A current program input is provided to control the current output. Two outp...

  • Page 40

    Lake shore model 642 electromagnet power supply user’s manual 3-12 installation 3.12 detachable handles the model 642 is supplied with 4 detachable handles to enable handling. The handles should normally remain attached to the unit. However, in some cases it may be necessary to remove the handles to...

  • Page 41: Chapter 4

    Lake shore model 642 electromagnet power supply user’s manual operation 4-1 chapter 4 operation 4.0 general this chapter provides operating instructions for the features of the model 642 electromagnet power supply. Computer interface instructions are in chapter 5. 4.1 turning power on verify that th...

  • Page 42

    Lake shore model 642 electromagnet power supply user’s manual 4-2 operation 4.2 display definition the model 642 has an 8 line by 40 character vacuum fluorescent (vf) display capable of showing both text and graphic images. The features displayed during normal operation include current measurement, ...

  • Page 43

    Lake shore model 642 electromagnet power supply user’s manual operation 4-3 4.4 keypad definition the model 642 has 22 keys separated into 3 groups on the instrument front panel. The sixteen keys in the center of the grouping combines instrument setup and data entry. The keys below control the outpu...

  • Page 44

    Lake shore model 642 electromagnet power supply user’s manual 4-4 operation 4.4.1 general keypad operation the model 642 uses three basic keypad operations, direct operation, setting selection, and data entry, for the majority of operator interface. A few specialized keypad operations, such as ramp ...

  • Page 45

    Lake shore model 642 electromagnet power supply user’s manual operation 4-5 setting output current (continued) to change the output current setting, press the output setting key. The output current setting value on the normal display will be highlighted to prompt for the new output current setting v...

  • Page 46

    Lake shore model 642 electromagnet power supply user’s manual 4-6 operation ramp segments (continued) to configure the ramp segments press ramp segments . The first ramp segments setup screen appears as a prompt for the ramp segments mode. Ramp segments select with °® ramp segments: enable use the s...

  • Page 47

    Lake shore model 642 electromagnet power supply user’s manual operation 4-7 4.11 maximum setting limits the model 642 offers a maximum setting limit for output current and ramp rate. Typical properties of the magnet will dictate these parameters. These maximum parameters should be entered before the...

  • Page 48

    Lake shore model 642 electromagnet power supply user’s manual 4-8 operation 4.12 magnet water the model 642 provides power to control an external magnet water solenoid control valve. The setup of the valve control is available in the magnet water menu. The four menu selections are auto, on, off, and...

  • Page 49

    Lake shore model 642 electromagnet power supply user’s manual operation 4-9 4.15 external current programming the output current of the model 642 can be set internally, externally, or by the sum of the external and internal settings. Normally, the current is controlled internally by entering a setti...

  • Page 50

    Lake shore model 642 electromagnet power supply user’s manual 4-10 operation locking the keypad (continued) to lock or unlock the instrument keypad press and hold the enter key for 5 seconds. The following setup screen appears as a prompt for the keypad lock mode. Keypad lock select with °® keypad l...

  • Page 51

    Lake shore model 642 electromagnet power supply user’s manual operation 4-11 4.17.2 changing ieee-488 interface parameters two interface parameters, address and terminators, must be set from the front panel before ieee-488 communication with the instrument can be established. Other interface paramet...

  • Page 52

    Lake shore model 642 electromagnet power supply user’s manual 4-12 operation table 4-3. Default parameter values output settings output current* .....................................0 a current ramp rate..................... 99.999 a/s maximum settings max output current..........................70....

  • Page 53: Chapter 5

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-1 chapter 5 computer interface operation 5.0 general this chapter provides operational instructions for the computer interface for the lake shore model 642 electromagnet power supply. Either of the two compu...

  • Page 54

    Lake shore model 642 electromagnet power supply user’s manual 5-2 computer interface operation 5.1.1 changing ieee-488 interface parameters two interface parameters, address and terminators, must be set from the front panel before communication with the instrument can be established. Other interface...

  • Page 55

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-3 5.1.3.1 bus control commands a universal command addresses all devices on the bus. Universal commands include uniline and multiline commands. A uniline command (message) asserts only a single signal line. ...

  • Page 56

    Lake shore model 642 electromagnet power supply user’s manual 5-4 computer interface operation message strings (continued) 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...

  • Page 57

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-5 service request name bit not rqs = service request mss = master summary status bit esb = event status sumary bit mav = message available summary bit osb = operation summary bit oesb = operational error sum...

  • Page 58

    Lake shore model 642 electromagnet power supply user’s manual 5-6 computer interface operation name name name used not used not 7 6 5 4 3 2 1 0 bit used used erst? Not used 7 not used 6 5 condition register error status 7 not 6 5 not 4 3 2 1 0 bit 4 3 2 1 0 bit dac ocf oov ooc tf tf tf and and and a...

  • Page 59

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-7 5.1.4.1.6 reading registers any register in the status system may be read using the appropriate query command. Some registers clear when read, others do not. Refer to paragraph 5.1.4.1.7. The response to a...

  • Page 60

    Lake shore model 642 electromagnet power supply user’s manual 5-8 computer interface operation 5.1.4.2 status register sets as shown in figure 5-1, there are five register sets in the status system of the model 642; standard event status register, operation event register, hardware error status regi...

  • Page 61

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-9 5.1.4.2.2 operation event register set the operation event register reports the following instrument events: ramp done, compliance. Any or all of these events may be reported in the operation event summary...

  • Page 62

    Lake shore model 642 electromagnet power supply user’s manual 5-10 computer interface operation 5.1.4.3 error status register sets as shown in figure 5-1, there are two register sets in the error status system of the model 642; hardware error status register, and operational error status register. 5...

  • Page 63

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-11 5.1.4.3.2 operational error status register set the operational error status register reports the following instrument operational error events: remote enable fault detected, power supply flow switch faul...

  • Page 64

    Lake shore model 642 electromagnet power supply user’s manual 5-12 computer interface operation 5.1.4.4 status byte and service request (srq) as shown in figure 5-1, the status byte register receives the summary bits from the two status register sets and the message available summary bit from the ou...

  • Page 65

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-13 5.1.4.4.2 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 r...

  • Page 66

    Lake shore model 642 electromagnet power supply user’s manual 5-14 computer interface operation 5.1.4.4.6 using operation complete (*opc) and operation complete query (*opc?) the operation complete (*opc) and operation complete query (*opc?) are both used to indicate when pending device operations c...

  • Page 67

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-15 figure 5-7. Gpib0 setting configuration figure 5-8. Dev 12 device template configuration.

  • Page 68

    Lake shore model 642 electromagnet power supply user’s manual 5-16 computer interface operation 5.1.5.2 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...

  • Page 69

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-17 table 5-4. Ieee-488 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 c...

  • Page 70

    Lake shore model 642 electromagnet power supply user’s manual 5-18 computer interface operation table 5-5. 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 tru...

  • Page 71

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-19 primary gpib address ........ Primary gpib address ........ à à 00 secondary gpib address ...... None secondary gpib address ...... None timeout setting ............. 10sec timeout setting ............. 1...

  • Page 72

    Lake shore model 642 electromagnet power supply user’s manual 5-20 computer interface operation 5.1.5.3 program operation once the 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 [...

  • Page 73

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-21 5.2 serial interface overview the serial interface used in the model 642 is commonly referred to as an rs-232c interface. Rs-232c is a standard of the electronics industries association (eia) that describ...

  • Page 74

    Lake shore model 642 electromagnet power supply user’s manual 5-22 computer interface operation 5.2.3 hardware support the model 642 interface hardware supports the following features. Asynchronous timing is used for the individual bit data within a character. This timing requires start and stop bit...

  • Page 75

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-23 message strings (continued) a query string is issued by the computer and instructs the instrument to send a response. The query format is: >. Query mnemonics are often the same as commands with the additi...

  • Page 76

    Lake shore model 642 electromagnet power supply user’s manual 5-24 computer interface operation 5.2.7.1 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 re...

  • Page 77

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-25 table 5-7 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 capt...

  • Page 78

    Lake shore model 642 electromagnet power supply user’s manual 5-26 computer interface operation table 5-8. 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 ...

  • Page 79

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-27 5.2.7.2 program operation once the 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 ...

  • Page 80

    Lake shore model 642 electromagnet power supply user’s manual 5-28 computer interface operation 5.3 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 5-9. All the commands are detailed in paragraph 5.3....

  • Page 81

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-29 table 5-9. Command summary command function page command function ...................................................... Page *cls clear interface cmd ..................................29 intwr? Internal ...

  • Page 82

    Lake shore model 642 electromagnet power supply user’s manual 5-30 computer interface operation * ese? Standard event status enable register query input: * ese?[term] returned: weighting>[term] format: nnn (refer to command for description) * esr? Standard event status register query input: * esr?[t...

  • Page 83

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-31 *sre service request enable register command input: * sre [term] format: nnn remarks: the service request enable register determines which summary bits of the status byte may set bit 6 (rqs/mss) of the st...

  • Page 84

    Lake shore model 642 electromagnet power supply user’s manual 5-32 computer interface operation dflt factory defaults command input: dflt 99[term] remarks: sets all configuration values to factory defaults and resets the instrument. The instrument must be at zero amps for this command to work. The "...

  • Page 85

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-33 erstr? Error status register query input: erstr? [term] returned: , [term] format: nnn,nnn remarks: the integers returned represent the sum of the bit weighting of the error bits. These error bits are lat...

  • Page 86

    Lake shore model 642 electromagnet power supply user’s manual 5-34 computer interface operation limit limit output settings command input: limit , [term] format: +nn.Nnnn, +nn.Nnnn specifies the maximum output current setting allowed: 0 – 70.1000 a. Specifies the maximum output current ramp rate set...

  • Page 87

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-35 opst? Operational status query input: opst? [term] returned: [term] format: nnn remarks: the integer returned represents the sum of the bit weighting of the operational status bits. Refer to paragraph 5.1...

  • Page 88

    Lake shore model 642 electromagnet power supply user’s manual 5-36 computer interface operation rdgv? Output voltage reading query input: rdgv? [term] returned: [term] format: ± n.Nnnn actual output voltage measured at the power supply terminals. Rseg ramp segments enable command input: rseg [term] ...

  • Page 89

    Lake shore model 642 electromagnet power supply user’s manual computer interface operation 5-37 stop stop output current ramp command input: stop [term] remarks: this command will stop the output current ramp within two seconds of sending the command. To restart the ramp, use the seti command to set...

  • Page 90

    Lake shore model 642 electromagnet power supply user’s manual 5-38 computer interface operation this page intentionally left blank.

  • Page 91: Chapter 6

    Lake shore model 642 electromagnet power supply user’s manual options and accessories 6-1 chapter 6 options and accessories 6.0 general this chapter provides information on accessories available for the model 642 electromagnet power supply. 6.1 accessories included part number description man-model ...

  • Page 92

    Lake shore model 642 electromagnet power supply user’s manual 6-2 options and accessories this page intentionally left blank.

  • Page 93: Chapter 7

    Lake shore model 642 electromagnet power supply user’s manual service 7-1 chapter 7 service 7.0 general this chapter provides basic service information for the model 642 superconducting magnet power supply. Customer service of the product is limited to the information presented in this chapter. Fact...

  • Page 94

    Lake shore model 642 electromagnet power supply user’s manual 7-2 service 7.3 line voltage selection the model 642 may be configured for four basic ac power configurations: 208 vac, 230 vac, 380 vac and 415 vac. Proper voltage selection must be made before connection to the power mains. Each configu...

  • Page 95

    Lake shore model 642 electromagnet power supply user’s manual service 7-3 terminal screw wire ferrule voltage selector card voltage indicator key figure 7-2. Voltage change detail 7.4 circuit breaker setting the main three-phase input power is protected by an automatic-reset circuit breaker within t...

  • Page 96

    Lake shore model 642 electromagnet power supply user’s manual 7-4 service current setting dial access cover figure 7-3. Circuit breaker 7. If incorrect, use a small straight blade screwdriver to reset according to table 7-1. 8. Close the circuit breaker access door. 9. Replace the power wiring acces...

  • Page 97

    Lake shore model 642 electromagnet power supply user’s manual service 7-5 figure 7-4. Fuse holder detail 7.6 error messages the following messages appear on the lower part of the instrument display when it identifies a problem during operation. The fault led will light in conjunction with the error ...

  • Page 98

    Lake shore model 642 electromagnet power supply user’s manual 7-6 service table 7-3. Operational errors remote enable fault detected the remote enable connection loop is not closed. The output setting is set to 0 a and no current entry will be allowed. Once the loop is closed, the error is cleared b...

  • Page 99

    Lake shore model 642 electromagnet power supply user’s manual service 7-7 7.7.2 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 pote...

  • Page 100

    Lake shore model 642 electromagnet power supply user’s manual 7-8 service firmware replacement (continued) 4. Disconnect the ribbon cable to the analog board assembly from j-2. 5. Disconnect the cable to the fan from j-3. 6. Disconnect the ribbon cable to the keypad board assembly from j-4. 7. Disco...

  • Page 101

    Lake shore model 642 electromagnet power supply user’s manual service 7-9 digital board figure 7-5. Board locations (top view).

  • Page 102

    Lake shore model 642 electromagnet power supply user’s manual 7-10 service vr 1 r7 4 c6 7 cr 1 8 l1 a u xi l iar y c 131 k3 cr10 r7 3 k2 vr 3 k5 c 132 j10 j9 ma gn e t f9 c1 3 0 r7 1 vr 2 cr9 r78 j8 locator pins tp6 u1 3 c43 r52 r2 3 c2 9 r3 2 c2 1 r22 r2 9 r1 7 r28 r18 r2 4 r1 3 c3 0 irdg cr4 u1 5 ...

  • Page 103

    Lake shore model 642 electromagnet power supply user’s manual service 7-11 7.10 connector and cable definitions all non-power electrical connections to the rear of the model 642 are detailed in this section. 7.10.1 analog i/o connector the analog i/o connector provides the connections for the extern...

  • Page 104

    Lake shore model 642 electromagnet power supply user’s manual 7-12 service 7.10.3 auxiliary connector the auxiliary connector provides connections for three functions: 1. Emergency stop – this normally-closed circuit turns off power to the model 642 just as if the off (o) button was pressed on the f...

  • Page 105

    Lake shore model 642 electromagnet power supply user’s manual service 7-13 7.10.4 power supply connector the power supply connector provides the means to connect a water control valve (24 vac) and an associated water flow switch (closed during flow) to protect the model 642 from loss of water flow. ...

  • Page 106

    Lake shore model 642 electromagnet power supply user’s manual 7-14 service 7.10.6 serial interface cable wiring the following are suggested cable wiring diagrams for connecting the model 642 serial interface to various customer personal computers (pcs). Model 642 to pc serial interface – pc with de-...

  • Page 107

    Lake shore model 642 electromagnet power supply user’s manual service 7-15 12 1 24 13 pin symbol description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 dio 1 dio 2 dio 3 dio 4 eoi dav nrfd ndac ifc srq atn shield dio 5 dio 6 dio 7 dio 8 ren gnd 6 gnd 7 gnd 8 gnd 9 gnd 10 gnd 11 g...

  • Page 108

    Lake shore model 642 electromagnet power supply user’s manual 7-16 service 7.11 calibration lake shore maintains a fully automated calibration fixture for the model 642 that measures existing performance of the unit and then recalibrates the using nist traceable resistance and voltage standards. In ...

  • Page 109

    Lake shore model 642 electromagnet power supply user’s manual service 7-17 7.11.2 calibration equipment 1. Calibration shunt resistor – the output current of the model 642 must be measured externally as the primary reference for calibration. When current is measured, it is the result of the current ...

  • Page 110

    Lake shore model 642 electromagnet power supply user’s manual 7-18 service 7.13.3.3 calibrate output voltage reading zero this step assumes that the previous two steps are successful and the current through the shunt resistor is quite low resulting in virtually no voltage across the model 642 output...

  • Page 111

    Lake shore model 642 electromagnet power supply user’s manual service 7-19 calibrate output current gain (continued) 12. Measure the actual voltage across the shunt and record (v shunt ). 13. Calculate and record (i minpostrim ): v shunt /r shunt . 14. Send “calg 10, 0”. To set the output current ga...

  • Page 112

    Lake shore model 642 electromagnet power supply user’s manual 7-20 service 7.13.3.6 calibrate current reading gain 1. Send “calg 0, 1”. To set the output current reading gain constant to 1. 2. Set the model 642 output current to –70 a. (ramp rate 30 a/s nominal). 3. Wait 30 seconds. 4. Measure the a...

  • Page 113

    Lake shore model 642 electromagnet power supply user’s manual service 7-21 7.11.3.8 calibrate external current programming voltage reading gain this procedure calibrates only the input voltage reading of the external programming input. The actual current output from this input is specified to a 1% t...

  • Page 114

    Lake shore model 642 electromagnet power supply user’s manual 7-22 service calg? Gain calibration constant query input: calg? [term] format: nn 0 – 10. Returned: [term] format: ±nnnnnnn (refer to command for description) calsave calibration save command input: calsave[term] remarks: saves all calz a...

  • Page 115: Appendix A

    Lake shore model 642 electromagnet power supply user’s manual glossary of terminology a-1 appendix a glossary of terminology accuracy . The degree of correctness with which a measured value agrees with the true value. 2 electronic accuracy . The accuracy of an instrument independent of the sensor. S...

  • Page 116

    Lake shore model 642 electromagnet power supply user’s manual a-2 glossary of terminology 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. Calibrate . To dete...

  • Page 117

    Lake shore model 642 electromagnet power supply user’s manual glossary of terminology a-3 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 measureme...

  • Page 118

    Lake shore model 642 electromagnet power supply user’s manual a-4 glossary of terminology 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...

  • Page 119

    Lake shore model 642 electromagnet power supply user’s manual glossary of terminology a-5 permeability . Material parameter which is the ratio of the magnetic induction (b) to the magnetic field strength (h): µ = b/h. Also see initial permeability and differential permeability. Platinum (pt) . A com...

  • Page 120

    Lake shore model 642 electromagnet power supply 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 r...

  • Page 121: Appendix B

    Lake shore model 642 electromagnet power supply user’s manual units for magnetic properties b-1 appendix b units for magnetic properties table b-1. Conversion from cgs to si units quantity symbol gaussian & cgs emu a conversion factor, c b si & rationalized mks c magnetic flux density, magnetic indu...

  • Page 122

    Lake shore model 642 electromagnet power supply user’s manual b-2 units for magnetic properties table b-2. Recommended si values for physical constants quantity symbol value (si units) permeability of vacuum µ 0 4 π × 10 -7 h m -1 speed of light in vacuum c 2.9979 × 10 8 m s -1 permitivity of vacuum...