Home

Lakeshore Learning Materials 622 User's Manual

1. LSCI Model 2001 RJ 11 Cable Assembly C MPS 4 2 eps Figure 4 2 Serial Interface Adapters Remote Operation i eeses lt i sSsS AT Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 2 1 Serial Interface Hardware Configuration Below is a technical description of the 6224 option card for the Serial Interface configuration Note See Appendix C for Serial Interface on CMP Table 4 2 defines communication parameters Terminators are fixed to Carriage Return CR and Line Feed LF The serial interface connector is a standard 6 wire RJ 11 telephone jack Lake Shore offers the Model 2001 10 foot Cable Assembly Model 2002 RJ 11 to DB 25 Adapter and the Model 2003 RJ 11 to DE 9 Adapter See Chapter 5 for Serial I O connector and adapter pinouts and for RJ 11 pinouts See Paragraph 5 7 for adapter wiring Table 4 2 Serial Interface Specifications Transmission Three Wire Bits per Character 1 Start 8 Data 1 Stop Baud Rate 300 1200 or 9600 Timing Format Asynchronous Parity Type None Connector Two RJ 11 Modular Socket Fixed Terminator CR ODH LF OAH Transmission Mode Half Duplex Data Interface Levels Transmits amp Receives Using EIA Voltage Levels 4 2 2 Serial Interface Settings To use the Serial Interface set the Baud rate Press the Function Menu key then press the function key corresponding to INTERFACE SETUP to display the screen to the right Use the cursor keys to mo
2. Positive voltage supply for programming external current with a potentiometer Remote voltage sense correction Correction for load lead drops of up to 0 5 V per lead OVP Im Vm m Vp Vs lIs Ip ls S S 7 8 9 10 11 12 13 14 15 16 17 18 ET Negative voltage supply for programming external current with a potentiometer Hu lata Lata 10K 10K Figure 2 2 Analog Monitoring Programming and Remote Sense Connections The factory configures the MPS to sense but not control remote voltage Call Lake Shore to reconfigure the MPS to control voltage at the load When using remote sense the MPS measures voltage at the magnet instead of at the MPS output terminals allowing a more accurate reading of magnet voltage by eliminating voltage drops in the leads connecting the MPS to the magnet If using remote sense the MPS bases the voltage at the voltage monitor output on the remote sense voltage instead of the MPS terminal voltage Use AWG 24 shielded twisted pair wiring for sense leads to minimize pickup of external noise Any noise on the sense leads may appear at the unit output Ground sense shield to the MPS back panel Make Remote Sense Connections to the rear panel detachable terminal block defined in Table 2 3 and Figure 2 2 Setup amp Connections 2 5 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual NOTE The MPS includes a protection circuit which reduces the effect of open sense leads durin
3. where Lactive is the sensor length line 2 Enter the computed value in line 4 manually Figure 6 1 NbTi Filament Resistance Chart a m iy P o EI Normalized Resistivity R g o N EI 0 100 200 300 Temperature K 6 2 7 Model 6226 6476 IEEE 488 Remote Operation Commands Cmd Function Cmd Function Cmd Function BFLD Magnetic Field Query LALMS Program Level Alarm Status PER Program Sample Period BUNI Program Field Units LALMS Level Alarm Status Query PER Sample Period Query BUNI Field Units Query LEVL Read Level ZREF Program Probe Zero Reference IBS Field Summary Query LEVL Level Query ZREF Probe Zero Reference Query LALM Program Level Alarm LUNI Program Level Units ZREFS Program Zero Reference Status LALM Level Alarm Query LUNI Level Units Query ZREFS Zero Reference Status Query BFLD Magnetic Field Query Input BFLD Returned A number between 999 9999 Remarks Returns nine characters plus up to two terminators BUNI Program Magnetic Field Units Input BUNI units where units kG for kilogauss or T for tesla 10 kilogauss Remarks The initial status is kG Verify there is a space between the command and the units parameter BUNI Magnetic Field Units Query Input BUNI Returned Either kG for kilogauss or T for tesla 10 kilogauss Remarks Returns two characters plus up to two terminators C6 Options amp Accessories IBS Input Returned Remarks LALM Input Remarks
4. 6 Determines whether the MPS is to report via the SRQ line and five bits determine which status reports to make If bits 0 1 2 3 4 and or 5 are set then the corresponding bit in the Status Byte Register is set The MPS produces 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 Service Request does not interrupt the BUS CONTROLLER The STB common query reads the Status Byte Register but does not clear the bits Certain bits in the Status Byte Register continually change Above are bit assignments in the Status Byte Register These reports occur only if the bits are enabled in the Service Request Enable Register Event Status ESB Bit 5 When set it indicates if one of the bits from the Standard Event Status Register has been set Refer to Paragraph 4 1 4 2 Overvoltage Protection OVP Bit 4 Indicates overvoltage quench protection circuit activation Error ERR Bit 3 Indicates operation error The error displays on the front panel and can be read using the TST Command Ramp Segment Complete RSC Bit 2 Indicates active ramp segment completion Limit Exceeded LIM Bit 1 Indicates a new current or voltage exceeds the current or compliance voltage limit Read the new setting with the ISET or VSET commands Output Data Ready ODR Bit 0 When
5. 647 ramp rate 0 to 99 9999 A S 00 Reserved for future use Operation to perform Need not be present for proper command operation Reserved for future use DWELL time in days hours minutes and seconds Does not need to be present for proper command operation Remarks Truncates value to 0 001 place Enter values with no embedded spaces Undefined parameters are set to 0 Control Bus inputs 4 places display rounds to 0 01 or 0 001 place Example RAMP1 125 0000 125 0000 01 0000 term Indicates Ramp Segment 1 Initial Ramp Current 125 0000 A Final Ramp Current 125 0000 A Ramp Rate 01 0000 A S commas can be replaced by blanks RAMP Ramp Parameter Query Input RAMP Returned Values are the same format as described above for programming in the ramp segments Remarks Returns 48 characters and up to two terminators RMP Programs Ramp Status Input RMP ramp status where ramp status 0 to turn off HOLD the ramp definitely or 1 to turn on the ramp segment or continue a ramp on hold RMP Ramp Status Query Input RMP Returned 0 for holding or 1 for ramping Remarks One character plus up to two terminators are returned SEG Programs Active Ramp Segment Input SEG segment where segment 1 Future updates will allow multiple ramp segments SEG Active Ramp Segment Query Input SEG Returned 1 Future updates will allow multiple ramp segments Remarks Returns one character plus
6. When the current zero is turned off the current zero value resets to 0 Current Zero Status Query ZIS 0 if the current zero is OFF or 1 if it is ON Returns one character plus up to two terminators Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 5 Current Step Limit Commands Description The following MPS commands configure the various functions of the current step limit features ISTP Input Remarks ISTP Input Returned Remarks ISTPS Input Remarks ISTPS Input Returned Remarks STEP Input Returned Remarks STEPR1 Input Returned Remarks 4 16 Programs Output Current Step Limit ISTP step limit where step limit a value between 0 and 999 9900 Truncates the value to the 0 001 place The initial condition is 000 000 A The step limit is forced to a plus Control Bus inputs 4 places display rounds to 0 01 or 0 001 place Output Current Step Limit Query ISTP A number between 0 and 999 9900 A Returns nine characters plus up to two terminators Value is shown as a but applies to both positive and negative step changes Programs Output Current Step Limit Status ISTPS status where status 0 to turn OFF output current step limit or 1 to turn it ON The initial condition is 0 Output Current Step Limit Status Query ISTPS 0 for OFF or 1 for ON Returns one character plus up to two terminators Output Current Step Limit Ex
7. and EOI active To use type an instrument command or query at the prompt The command transmits to the instrument and the MPS receives and displays the response If no query is sent the instrument responds to the last query received Type EXIT to exit the program NOTE The INPUT instruction accepts no commas as part of an input string If a comma appears in an instrument command replace it with a space REM S INCLUDE c gpib pc qbasic qbdecl bas Link to IEEE calls CLS Clear screen PRINT IEEE 488 COMMUNICATION PROGRAM PRINT CALL IBFIND dev12 DEV12 Open communication at address 12 TERMS CHRS 13 CHR 10 Terminators are lt CR gt lt LF gt INS SPACES 2000 Clear for return string INPUT ENTER COMMAND or EXIT CMDS Get command from keyboard CMD UCASES CMD Change input to upper case IF CMDS EXIT THEN END Get out on Exit CMDS CMDS TERMS CALL IBWRT DEV12 CMDS Send command to instrument CALL IBRD DEV12 INS Get data back each time ENDTEST INSTR INS CHRS 13 Test for returned string IF ENDTEST gt 0 THEN String is present if lt CR gt is seen INS MIDS INS 1 ENDTEST 1 Strip off terminators PRINT RESPONSE INS Print return string ELSE PRINT NO RESPONSE No string present if timeout END IF GOTO LOOP2 Get next command Remote Operation A8 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual National Instruments G
8. not rounded to the tenths place The initial condition is 0 The zero reference uses the existing units Conversion is made if units are changed Probe Zero Reference Query ZREF A number between 999 9000 Returns nine characters plus up to two terminators Program Probe Zero Reference Status ZREFS status where status 1 to add the zero reference value to the level reading or 0 to return the level reading to absolute Programs the probe zero reference status The initial condition is 0 The level read above the zero reference is positive while the level read below the zero reference is negative Zero Reference Status Query ZREFS 0 if the probe zero reference status is disabled or 1 if it is enabled Returns one character plus up to two terminators Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 6 3 MODEL 6228 AND 6228 8MUX PERSISTENT SWITCH HEATER OUTPUT The Model 6228 Persistent Switch Heater PSH Output Option provides a variable 0 124 mA DC output in 4 mA increments The output compliance is an 8 volt minimum and the load can be up to 100 ohms An MPS front panel annunciator indicates PSH output current status Model 6228 specifications are as follows Output Range 0 to 124 mA Load 100 ohms maximum Output Resolution 4 mA Off State Leakage Current Less than 1 mA Output Compliance 8V minimum 8 7 typical at 124 mA The Model 6228 output current is present on
9. 0 001 kG ampere or 0 0001 tesla ampere Be aware of MPS units via the CFUNI query so as not to be in error by a factor of 10 Computed Field Ampere Constant Query CFPA Anumber between 0 and 9 999 kG ampere or 0 9999 tesla ampere Query units with CFUNI to verify correct units Returns 5 character plus up to 2 terminators Program Computed Field Display Units CFUNI Units where Units K displays kG Units T displays tesla Enable computed field status with CFPS to display computed field Computed Field Units Query CFUNI Returns K if units kG T if units tesla Returns 1 character plus up to 2 terminators Set Computed Field Display Status CFPA Status where Status 0 displays amperes Status 1 displays Computed Field The computed field kG or tesla based on the CFUNI units Computed Field Status Query CFPA 0 amperes currently displayed 1 Computed Field currently displayed Returns 1 character plus up to 2 terminators Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 7 Common Commands Description The MPS Common Commands below are input output commands defined by the IEEE 488 standard and shared with other instruments complying with the standard Common commands begin with CLS Clear Status Register Command Input CLS Returned Nothing Remarks Clears the Status Register but not the instrument It clears the bits in the Status Byte Register and the Standard Even
10. 1 stop bit CB ADD 0 Control Bus Address VW ANGLE 5 Viewing Angle 5 Straight On MF ID 622 1 Mainframe ID Number Liquid Helium Level Screens If Present READING 00 00 lt OFF gt Level Reading and Status UNITS in E Level Probe Units Inches English NEXT RDG 00 00 Next Reading HH MM PERIOD 01 00 Period HH MM ALARM 0 0 lt OFF gt Level Alarm and Status ZERO REF 0 0 lt OFF gt Level Zero Reference and Status Field Screen If Present Persistent Switch Heater PSH Screen If Present FIELD PROBE SETTING HEATER 50mA PSH Current UNITS kG Field Units in Kilogauss STATUS lt OFF gt PSH Status CALIBRATE PROBE LAST END 0 000A Ending current from last magnet charge mV kG 0 800 Field Probe Sensitivity BO Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 5 3 CALIBRATION NOTE Calibration is only as accurate as the current monitor shunt The factory uses a current monitor shunt rated at 0 02 accuracy Shunt manufacturers typically stock accuracy values of 0 25 or better To use a different value adjust readings given in the procedure 1 Equipment requirements for MPS calibration a Current monitor shunt 100 mV output at 100A 1 millionm 0 02 accurate b Load resistor 10V at 100A 0 1 ohm 1 kW c Digital Volt Meter DVM with a resolution of 100 nV 6 digits 0 0035 accurate
11. 250 VA contin Max Power 1 kVA contin Max Power 1 kVA contin Max Power 2 kVA contin Remote Sensing Corrects for load lead drop of up to 0 5 V per lead Operation with more drop per load lead is possible with a degradation of the load effect specification Output Terminals The two rear panel output bus bars are isolated from the chassis earth ground Multiple Unit Operation Connect up to four units in an auto parallel configuration for increased output current capability Protection Front panel annunciators an audio indicator and a contact closure indicate faults Remote Inhibit RI An active RI forces output settings to 0 A and 1 V until the RI is no longer active To continue normal operation enter new output settings Output Inhibit Ol Press the front panel Ol key to force output settings to 0 A and 1 V To continue normal operation enter new output settings Output Current Step Limit The output current settings are forced to 0 A and 1 V if a preset current step limit is exceeded A key entry is required to continue operation Utility Low Line or Loss Maintains operation until load is discharged or utility is restored Utility High Line Turns off input and maintains operation until load is discharged Overvoltage Crowbars output when output terminal voltage induced by the load exceeds 40 VDC Overtemperature Crowbars output and turns off input when internal heat sink temperature exceeds 95 C AC Input Mode
12. 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 620 622 623 647 Magnet Power Supply User s Manual TABLE OF CONTENTS Chapter Paragraph Title Page gell EE le iv PEMAN oE cities A te ele ds eet eed eth ciate Nats dated E sate ees iv OPE WONG iye n coke aes ash wth Dain cts Get ek a iain ca Auted Pats acetate alah v Wee lee Ee ee v e Tue Ee d WEE v Warnings Cautions and Notes 0 ccccccecccceeeeeeeeeneae cece eeeecaaeaeeeeeeeseceaaaeeeeeeeeeseccneaeeeeeeeeesecsueeseeeteees V General Installation Precautions ccccceceeeeeeeececeeeeeeecenaeaeeeeeeeseceaaeeeeeeeeesecaeaeeeeeeesesecnaeseseeeeteeeaees v Electrostatic Discharge esscr grii aiiai ii aeaa EE AAEE EE AE EEA ANEA EA A v Handling Electrostatic Discharge Sensitive Components eee ceeeee ee eeeeeeeeeeeeeeeeeeeaeeeeeeeeeeeeanens vi Safe Handling of Liquid Crvogens sc eaasin eoriet anner rAr Ee A ERARA REK EEA EA AEE Ei E EARS A vi Magnet uereg eeaeee aE EEE As EEEE EAEE ATETEA EES EAEE AEEA educa ett eas vi IR Gre Ee vi Before You Operate the Eoupment cece eeeesecaaeaeceeeeesesecaaeaeeeeeeesesencaeaeeeeeseeeaees vii e SUMMARY EE vii ately SYMBOIS E cuentas Alas een ae tae ee dante noses itn aciaediies viii T INTRODUCTION eis ctsciscsctcniv
13. As Saved Value When the PSH is turned ON the MPS checks the present current setting against the current setting stored when the PSH was turned OFF If the two Maximum Power Output Exceeded do not match the MPS sounds an alarm for about When users utilize external current programming and 2 second and displays output power exceeds 1000 watts the MPS ali ig 5 OUTPUTS r 2 Press the Data Entry up or down arrow to turn the PSH ON Press no key for approximately 30 seconds or press Esc to keep the PSH OFF Front panel settings are software limited to prevent power over 1000 watts ErrorMessages amp Troubleshooting 83 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 5 2 Factory Default Settings Below is a list of factory presets To reinitialize the MPS to factory presets at any time hold the Esc key for about 15 seconds NOTE If the MPS is part of a superconducting magnet system the system supplier may change some of the parameters below to optimize MPS operation to the superconducting magnet it works with Automatic Mode Screen This screen is unavailable if PSH option is not installed MGT START 0 000A Magnet Start MGT END 0 000A Magnet End MGT RATE 1 000A S Magnet Rate PERS RATE 1 000A S Persistence Rate LAST END 0 000A Ending current from last magnet charge PERSISTENCE lt ON gt Persistence Mode Status RUN Ramp Start Toggle Automatic Mode De
14. Enable Repeat Addressing 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 Listen address 10 64 74 Talk address L F1 Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board Figure 4 1 Typical National Instruments GPIB Configuration from IBCONF EXE Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 2 SERIAL I O INTERFACE RS 232C is a standard of the Electronics Industries Association EIA and one of the most common interfaces between a computer and electronic equipment The Customer supplied computer must have a Serial Interface port The MPS Serial Interface complies with the electrical format of the RS 232C Interface Standard A Serial Interface between the computer and the MPS permits remote monitoring and control of MPS control functions which in turn controls MPS operation See Figure 4 2 The Serial Interface can both transmit and receive information In transmit Tx mode the instrument converts parallel information to serial and sends it over a cable up to 50 feet long or longer with proper shielding In receive Rx mode the instrument converts serial information back to parallel for processing See Paragraph 4 2 1 for Serial Interface hardware configuration and adapters Paragraph 4 2 2 for Serial Interface settings and Paragraph 4 2 3
15. LALM Input Returned Remarks LALMS Input Remarks LALMS Input Returned Remarks LEVL Input Remarks LEVL Input Returned Remarks LUNI Input Remarks Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Magnetic Field Summary Query IBS IOUT BFLD STB Returns 23 characters plus up to two terminators Program Level Alarm LALM alarm where alarm is the level value between 0 and 999 9 that activates the alarm The value is truncated not rounded to the tenths place The initial condition is 0 The alarm value uses the existing units Conversion is made if units are changed Level Alarm Query LALM The value returned is a number between 999 9000 Nine characters plus up to two terminators are returned Program Level Alarm Status LALMS status where status 0 for OFF or 1 for ON The initial condition is 0 Level Alarm Status Query LALMS 0 or 1 0 indicates that the level alarm has not been reached 1 indicates that the level is below the alarm value and the alarm has been activated Returns one character plus up to two terminators Read LHe Level LEVL status where status 1 to read the level or 0 not to read it Reading the level requires a minimum of 5 seconds to update the level reading LHe Level Query LEVL A number between 999 9000 Returns nine digits plus up to two terminators Program
16. LHe Level Units LUNI units where units for percentage E for English units inches or M for metric units centimeters The initial condition is E inches Make sure there is a space between the command and the units parameter 6 7 LUNI Input Returned Remarks PER Input Remarks PER Input Returned Remarks ZREF Input Remarks ZREF Input Returned Remarks ZREFS Input Remarks ZREFS Input Returned Remarks 6 8 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual LHe Level Units Query LUNI for percentage E for English units inches or M for metric units centimeters Returns one character plus up to two terminators are returned Program Sample Period PER hours minutes where hours 0 to 23 and minutes 0 to 59 Programs the sample period in hours and minutes The initial condition is 00 00 which defines a continuous sample period Max time is 23 hours 59 seconds Sample Period Query PER Hours and minutes programmed for the sample period a comma then the hours and minutes left in the sample period Example 23 59 10 10 term Indicates an initial sample period program of 23 hours and 59 minutes with 10 hours and 10 minutes remaining Returns eleven characters plus up to two terminators Programs the probe zero reference ZREF zero reference where zero reference a value between 0 and 999 9 truncated
17. MODE BA FLT ON yo S OVP Im Vm m Vp Vs ls Ip s S S CAL AND ID 2 4 6 7 8 9 10 11 12 13 14 15 16 17 18 UN EE Open bs bes Fe be Ps Fe P Fe Fe P Fe Fe be bs E be bs 87654321 Ly w L m initi Table 5 1B Rear Panel CAL Table 5 1A Rear Panel Connector Definitions AND ID Switch Definitions RI 1 3 LSB Multi 2 RI Mainframe Address Fault indicat K F add Multi Mainframe ault Indicator Normally open contact closure r FLT to indicate a fault condition has occurred FLT 8 w Remote Inhibit Active low TTL compatible input to remotely disable the output force the output settings to 0 A and 1 V Contact rating 0 25 A resistive at 100 VDC 3 W Not Used Ee Inhibit Delay 7 ON Indicator Contact closure to indicate when ON the front panel circuit breaker is in the ON ON position Contact rating 0 25 A resistive at 100 VDC 3 W 25 VA Figure 5 2 Serial Overvoltage Protection Enable Analog signal connected in parallel to other MPS Units to remotely activate the output overvoltage protection circuit Output me Monitor Voltage output from Im to GND M is 0 01 V A Output M monitor Voltage output from Vm to GND M is 0 01 V V Table 5 2 Serial Interface Connector Definition Monitor and program ground GND M RS 485 FUNCTION KS Factory Use Only Enable external output current programming via Receive MODE switch Data Voltage input from Ip to GND M is 0 01 V A Si
18. OVP Connections 2 5 4 AC On Indicator The MPS provides a discrete ON indicator Terminals 5 and 6 on the terminal block connector shown in Figure 2 1 above connect to relay contacts that close when the front panel circuit breaker is in the ON position There is also a front panel LED that lights when the MPS is ON and connected to AC power 2 5 5 OVP Connection In auto parallel MPS configurations this connection synchronizes the firing of the Over Voltage Protection OVP circuits of each MPS see Paragraph 4 7 4 See Paragraph 2 6 and Figure 2 4 for auto parallel connections Setup amp Connections Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 2 5 6 MPS Analog Current And Voltage Monitoring Connections The MPS provides amplified and buffered current and voltage monitor output signals at the terminal block on the back panel Connect these signals to external meters to indicate output current and voltage Obtain the Current Monitor signal through connections to terminals 9 Im and 11 m with positive output currents producing a positive monitor voltage of 10 mV A from Im to m Obtain the Voltage Monitor signal through connections to terminals 10 Vm and 11 m with positive terminal voltages producing a positive monitor voltage of 10 mV V from Vm to m 2 5 7 External Current Programming Remotely program MPS output current by an external voltage or potentiometer Enable external analog progr
19. Remote Command Gummanm B 5 B 2 Additional MPS Mainframe Control Bus Remote Commands c ccecceceeeeeeeeeeceeeeeeeeeeeecaeeeeees B 6 iv Table of Contents Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual FOREWORD PURPOSE AND SCOPE This manual contains user instructions for the Model 620 622 623 647 Magnet Power Supply MPS Lake Shore Cryotronics Inc designed manufactures and assembles the MPS in the United States of America We welcome your comments concerning this manual Although every effort has been made to keep it free of errors some may occur To report a specific problem please describe it briefly and include the manual title revision number date the paragraph figure table number and the page number Send comments to Lake Shore Cryotronics Inc Attn Technical Publications 575 McCorkle Blvd Westerville Ohio 43082 8888 HARDWARE COVERED The MPS is available in the following configurations Model 620 50 A 5 V 250 VA Model 623 155 A 30 V 1 kVA Model 622 125 A 30 V 1 kVA Model 647 72 A 32 V 2 kVA Page A of this manual following the title page details the options installed in your unit See Chapter 6 for detailed definitions of hardware configurations WARNINGS CAUTIONS AND NOTES Warnings cautions and notes appear throughout this manual and precede the step to which they pertain Multiple warnings cautions or notes are bulleted WARNING An operation o
20. Train personnel in proper emergency measures such as electrical power shut off fire department notification fire extinguishing and personnel and records evacuation Here is a list of suggested personnel safety considerations e Ground Fault Interrupter GFI AC circuits e Fire Extinguisher e Magnetic Field Warnings e Emergency Lighting Locate in the immediate vicinity fire extinguisher s that extinguish all three classes of fires A B and C Class A is ordinary combustibles like wood paper rubber many plastics and other common materials that burn easily Class B is flammable liquids like gasoline oil and grease Class C is energized electrical equipment including wiring fuse boxes circuit breakers machinery and appliances Do not use chemical extinguishers even though they are less expensive and cover all classes of fires They may damage electronic equipment Use a Carbon Dioxide or Halon fire extinguisher During the planning stage consult local experts building authorities and insurance underwriters on locating and installing sprinkler heads fire and smoke sensing devices and other fire extinguishing equipment Even where not required by code install some type of automatic battery operated emergency lighting in case of power failure or fire SAFETY SUMMARY Observe the following general safety precautions during all phases of operation service and repair of this instrument Failure to comply with these precautions or
21. a detachable terminal block with the I output on the terminal towards the top of the board 1 and the I terminal towards the bottom of the board 2 6 3 1 Installation WARNING e This procedure is intended for trained service personnel who understand electronic circuitry and the hazards involved Do not attempt this procedure unless qualified e To prevent shock hazard turn off the instrument and disconnect AC line power and all test equipment before removing cover NOTE With multiple MPS units install the Model 6228 in MPS1 for proper operation The 6228 is factory installed if ordered with a MPS or can be field installed at a later date For field installation use the following procedure 1 Turn off the MPS and disconnect the power cord 2 Locate the Optional Plug In Board Slots on the MPS rear panel Remove the two screws that secure a blank cover plate to the MPS rear panel and remove the cover plate 3 Slide the Model 6228 board into the MPS with the board handle towards the bottom of the MPS Tighten the two screws that secure the board to the MPS rear panel 6 3 2 Model 6228 Operation Access PSH Control from the MPS front panel Press Function Menu then Next Menu to display Function Menu 2 If the 6228 PSH Option is not present lt NP gt appears next to PSH SETUP and the associated function key is ignored Press the PSH SETUP function key to enter the PSH Screen The cursor up and down keys mo
22. a proprietary pulse width modulated technique that incorporates power hybrid circuitry Extremely low conduction loss components minimize internal power dissipation The MPS is not a direct off line switching supply The output is fully floating and isolated from ground Active power factor correction draws a sinusoidal AC current waveform from the utility minimizes AC line harmonics and lowers AC current required Power factor is the ratio of real power measured in watts to the apparent power measured in volt amperes The combination of quiet switched mode design and active power factor correction results in a compact highly efficient air cooled unit Conventional MPS Most use linear regulated outputs The output transistor pass bank internally dissipates power not delivered to the magnet Some units use an off line switching supply to provide the bulk power and add output regulation There is no input power factor correction Low overall efficiency means higher input power and current Without power factor correction a non sinusoidal current with high peaks places tremendous stress on fuses circuit breakers outlets and wiring Dedicated lines may be required because of potential interaction with other equipment These factors result in low overall efficiency large size and considerable weight 1 6 Introduction Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTER 2 INITIAL SETUP AND CONNECTIONS 2 1 INSPECTI
23. activate output overvoltage protection circuits and turn off output circuits If a charged load is present OVP circuits discharge it The front panel Fault annunciators turn ON and the internal audio indicators beep about once per second If a MPS detects a fault it initiates Multiple MPS Remote Inhibit Mode by closing the FLT contacts No delay is allowed CAL AND ID switch 7 OFF down position and multiple MPS operation CAL AND ID switch 4 ON up position must be selected After the load discharges turn OFF all units to reset Setup amp Connections Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 2 7 POST INSTALLATION INSTRUCTIONS The MPS is electrically and mechanically inspected and operationally tested prior to shipment It should be damage free and in perfect working order upon receipt To confirm this visually inspect the instrument for damage and test it electrically to detect any concealed damage upon receipt Study the entire MPS User s Manual before attempting to run the unit See Chapter 3 for any questions on front panel control operation 2 8 SYSTEM SHUTDOWN AND REPACKAGING FOR STORAGE OR SHIPMENT Follow these general guidelines for system shutdown for storage or reshipment If returning something call Lake Shore first to obtain a Return Goods Authorization RGA Number 1 Turn off the power to all instruments Unplug the power cord 2 Remove or disconnect any interface cables and the magnet curre
24. appears to the right Note that the Channel displays for the 6228 8MUX card The heater currents and channel of the 6228 8MUX can be changed on this screen The status of the heater is either on or off The last value LAST 1 is the current of the power supply when the heater was last turned off for the given channel of the 6228 8MUX The PSH SETUP screen using ONLY a 6228 2 card appears to the right O12 Options amp Accessories 6 4 1 IPSHB Input Remarks IPSHB Input Returned Remarks PSHB Input PSHB Input Returned Remarks PSHBC Input Returned Remarks PSHBIS Input Returned Remarks PSHBS Input Returned Remarks Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Model 6228 2 Remote Operation Commands Program PSH Current IPSHB current where current a value from 0 to 125 mA The initial condition is 0 mA Current can be set from 0 to 125 mA but will actually be set in 4 mA increments PSH Current Query IPSHB A number between 0 and 125 Returns three characters plus up to two terminators Program PSH Heater Status PSHB status where status 0 to turn OFF the persistent switch heater or 1 to turn ON the persistent switch heater Heater ON means persistence is OFF PSH Heater Status Query PSHB 0 if the heater is OFF or 1 if the heater is ON If a current setting of 0 is entered
25. board handle towards the bottom of the MPS Tighten the two screws that secure the board to the MPS rear panel If Required Install the option removed from the Model 6224 slot into a different slot Set the IEEE 488 operating parameters as outlined in Paragraph 4 1 1 and the Serial Interface as outlined in Paragraph 4 2 2 6 2 MODEL 6226 6476 LIQUID HELIUM LEVEL AND GAUSSMETER INPUT CARD The Model 6226 6476 Liquid Helium Level and Gaussmeter Input Option combines liquid helium level and field monitoring in one input card It monitors liquid level in percent inches or centimeters and field in kilogauss or tesla The field measurement is quantitative Each input has independent excitation The level probe interfacing supports NbTi superconducting filaments and includes entry of probe length and determination of probe resistance over the length A unique level probe zero reference feature allows the user to define the current liquid level reading as the zero reference and reads levels above or below that reference A software level alarm notifies the user when the continuously variable liquid level set point has been reached When the liquid level measurement is not active the field measurement is The field interfacing supports Hall sensors and includes probe zero and entry of probe sensitivity in millivolts per kilogauss The Model 6226 and Model 6476 have the same level circuitry The Model 6226 Gaussmeter is designed to operate wit
26. e Output Current Step Limiting Magnet inductance and compliance di dt Vge7 L limit the output ramp programming charging current Program output for a constant 0 01 to 99 99 amperes per second as long as compliance is not exceeded Energize or de energize the magnet at a pre set ramp rate Pause the ramp at any time during the ramp During a pause the MPS maintains output values until the ramp continues Operating Ambient Temperature 15 to 35 C 59 to 95 F Dimensions 483 mm wide x 178 mm high x 508 mm deep 19 x 7 x 20 inches Weight 43 5 kilograms 96 pounds Rack mounting is standard Table 1 3 Model 620 622 623 DC Output Specifications SPECIFICATION Digital Programming Resolution for 620 622 Digital Programming Resolution for 623 Digital Programming Repeatability Electronic Resolution for 620 622 Electronic Resolution for 623 Stability Drift at 25 1 C Percent of full scale output change over 8 hours under constant line and load after 0 005 ES 3 mV a 30 minute warm up Ripple and Noise 10 Hz to 10 MHz at 1000 VA 20 pA rms 10 mV rms Temperature Coefficient Change in output per C 0 01 Lu 3 mV after 30 minute warm up Source Effect Line regulation for any line change within 0 005 LL 15 mV the rated line voltage Load Effect Load regulation for a load change equal to maximum voltage in Constant Current Mode or maximum 0 01 lax 3 mV current in Constant Voltage Mode Analog Resistance Programming Accur
27. functions to perform Below are MPS IEEE 488 interface capabilities e H1 Source handshake capability e SR1 Service request capability e RL1 Complete remote local capability e AH1 Acceptor handshake capability e DC1 Full device clear capability e PPO No parallel poll capability e DTO No device trigger capability e C0 No system controller capability e T5 Basic TALKER serial poll capability talk only unaddressed to talk if addressed to listen e L4 Basic LISTENER unaddressed to listen if addressed to talk 4 1 1 IEEE 488 Interface Settings To use the IEEE 488 interface the user must set the IEEE Address and Terminators Press the Function Menu key then press the key corresponding to INTERFACE SETUP to display the Interface Setup screen Use the cursor keys to move the arrow indicator to IEEE ADD and TRMS EOI IEEE ADD 1 to 30 Use the Data Entry up or down arrows to increment or decrement the IEEE Address The default value is 12 The range of choices is from 1 to 30 TRMS EOI CR LF LF CR DAB LF with or without EOI Use the Data Entry up or down arrows to cycle through the following choices CR LF EOI LF CR EOI DAB EOI LF EOI CR LF LF CR DAB LF If turned on End Or Identify EOI is asserted during the last byte of a multibyte transfer The default is Carriage Return and Line Feed CR LF with EOI ON Remote Operation A Lake Shore Model 620 622 623 647 Magnet Power Supply User s Ma
28. hardware installed for mounting in a standard 19 inch rack enclosure CAUTION To install the MPS in a 19 inch rack mount enclosure at any position other than the bottom install a slide rail or runner to support the MPS 2 3 ENVIRONMENTAL REQUIREMENTS Operate the MPS in an area with an ambient temperature range of 20 to 30 C 68 to 86 F The unit may be operated within the range of 15 to 35 C 59 to 95 F with reduced accuracy The MPS is intended for laboratory use no specific humidity or altitude specifications have been determined However relative humidity of 20 to 80 percent no condensation and altitudes from sea level to 2 4 km 8 000 feet are generally acceptable WARNING To prevent electrical fire or shock hazards do not expose this instrument to moisture Provide adequate ventilation The fan cooled MPS draws air in from the sides and exhausts it from the rear install it with sufficient space at the rear and sides for air flow Filter dust and other particulate matter at the site to a reasonable level For salt air corrosive gases or other air pollutants consult an air conditioning expert for special filtering arrangements 2 4 CONNECTING THE MPS TO POWER Read and thoroughly understand sections 2 4 1 through 2 4 3 and the safety recommendations in the Foreword before connecting the MPS to power Failure to do so may expose operating personnel to lethal voltages or damage the magnet and or MPS Setup amp Connec
29. leads large enough to handle the total output current of both MPS units NOTE For proper operation turn on MPS 1 and then MPS 2 within 15 seconds of MPS 1 Verify all connections as summarized in Table 2 4 Table 2 3 Two MPS Autoparallel To add a third MPS or a fourth MPS in parallel make the RI FLT Configuration Connections OVP CMP and output connections in parallel with the connections of MPS 1 and MPS 2 For MPS 3 set the CAL AND ID switches on the rear panel as follows switches 5 through 8 Control Bus Control Bus are OFF switches 4 3 2 and 1 are ON OFF ON ON 8 OVP 8 OVP respectively For MPS 4 set the rear panel CAL AND ID 1 RI 3 FLT 1 RI 3 FLT switches as follows switches 5 through 8 are OFF switches 4 2 RI 4 FLT 2 RI 4 FLT 3 2 and 1 are ON ON OFF OFF respectively Configure the OUT OUT CMP switches for MPS 3 and MPS 4 as those in MPS 1 and OUT OUT MPS 2 NOTE For proper operation turn on MPS 1 and then the remaining MPS units within 15 seconds Setup amp Connections gt gt S a Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual e MPS 2 Rear View Figure 2 4 Typical Multiple MPS Connections for Two MPS Units 2 6 1 Multiple MPS Remote Inhibit Mode In multiple MPS configuration if the MPS RI indicators activate from an external contact closure the MPS units enter Multiple MPS Remote Inhibit Mode They
30. option Without the PSH Function Menu 3 will not appear 3 6 3 1 Delays Setup Screen Select DELAYS using the Function key to display the Delays screen Here the user programs four delays associated with Automatic Mode RUN UP The time between initial ramp up to current and PSH activation Persistence Mode OFF The delay allows persistence switch current to settle Specify a time from 1 to 999 seconds Default is 60 seconds PERS OFF The time between PSH activation Persistence Mode OFF and initial ramp to setpoint The delay allows persistence switch to go normal Specify a time from 1 to 999 seconds Default is 60 seconds RAMP END The time between ramp up to setpoint and PSH deactivation Persistence Mode ON The delay allows magnet current to settle Specify a time from 1 to 999 seconds Default is 60 seconds PERS ON The time between PSH deactivation Persistence Mode ON and initial ramp back to zero The delay allows the persistence switch to superconduct Specify a time from 1 to 999 seconds Default is 60 seconds 3 8 Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 6 3 2 DELAY SETUP SCREEN WITH DITHERING To access the dithering feature turn ON up position switch 5 of the rear panel CAL AND ID DIP switches Select DELAY DITHER from Function Menu 3 to display the AUTOMATIC MODE DELAY screen to the right DITHER XXS The dwell in seconds for each of five dither
31. polarity change of the output voltage The active area of the Model HGCA 3020 Axial Hall Sensor is approximately 0 03 inch in diameter in the center of the face opposite the leads When the control current is applied with the red lead positive with respect to the black lead and the magnetic field is perpendicular into the face of the probe opposite the leads the Hall voltage is positive at the blue lead with respect to the yellow lead Again a reversal in mechanical orientation or in the direction of either the magnetic field or control current results in a output voltage polarity change Handle the Hall sensor with care The ceramic substrate is brittle and very sensitive to bending stress Mount the sensor to minimize mechanical strains as the sensor cools Failure rates approaching 10 occur on initial cool down with improperly installed sensors sensors surviving initial cool down generally experience no problems on subsequent cycles Avoid applying tension to the leads Bend the leads at any angle so long as the bend is at least 0 125 inch away from the substrate connection Mount the device to a non flexible smooth surface with a coefficient of thermal expansion no greater than a factor of three different from that of the ceramic substrate about 7 x 10 in in per K C20 Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Locate the probe in a cavity that is 0 003 inch wider and 0 01 inch long
32. set makes current and voltage readings available 4 1 3 2 Standard Event Status and Standard Event Status Enable Registers The Standard Event Status Register supplies various conditions of the instrument STANDARD EVENT STATUS REGISTER FORMAT Bits 2 and 6 are not used The reports of this register occur only if the bits are enabled in the Standard Event Status Enable Register along with bit 5 of the Service Request Enable Register Remote Operation 83 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual The Standard Event Status Enable Register enables any of the Standard Event Status Register reports The Standard Event Status Enable command ESE sets the Standard Event Status Enable Register bits Set a bit to enable its function To set a bit send the ESE command with the bit weighting for each bit to set added together See the ESE command for further details The Standard Event Status Enable Query ESE reads the Standard Event Status Enable Register ESR reads the Standard Event Status Register Once this register is read all bits are reset to zero Power On PON Bit 7 This bit is set when the power cycles from OFF to ON Command Error CME Bit 5 Set upon detection of a command error since the last reading This means the instrument could not interpret the command due to a syntax error unrecognized header unrecognized terminators or unsupported command Execution Error EXE Bit 4 Set u
33. the corresponding Display Function key places the MPS in MANUAL PSH control mode 3 6 1 2 Interface Setup Screen Press the Function Menu key followed by the INTERFACE SETUP Function key to display setup screen to the right Use the Cursor keys to move the line indicator up or down Parameters with a icon change with the Data Entry up or down key Change all others using any numeric entry mode including the cursor IEEE ADD 1 to 30 Defines the IEEE Address The default is 12 TRMS EOI CR LF LF CR DAB LF with or without EOI Choose from the following options CR LF EOI LF CR EOI DAB EOI LF EOI CR LF LF CR DAB LF When EOI displays End Or Identify EOI is asserted during the last byte of a multibyte transfer The default is Carriage Return and Line Feed CR LF with EOI ON RS 232C 1200 N 8 1 Select 300 1200 or 9600 Baud The other parameters are fixed at No Parity 8 Data Bits and 1 Stop Bit CB DEF 9600 0 7 1 Read only Control Bus Definition Fixed at 9600 Baud odd parity 7 data bits and 1 stop bit See Appendix C CB ADD 0 to 32 Control Bus Address See Appendix C VW ANGLE 2to9 Display viewing angle 9 indicates viewing from above 5 in the middle and 2 from below Initial value is 5 MF ID 620 1 622 1 623 1 or 647 1 Read only MPS ID A 1 indicates only one MPS On the master MPS MP 1 of a multiple MPS configuration the number indicates the number of units con
34. the MPS charged the magnet The MPS sets this field after it charges the magnet to the Magnet End value Once it reaches Magnet End the MPS sets the value of Last End equal to the value of Magnet End The user cannot change the Last End value The MPS stores it in non volatile memory and remembers it even when the MPS is Off PERSISTENCE lt ON gt or lt OFF gt Read only Persistence Mode Status If Persistence Mode is On the PSH heater is Off If it is Off the PSH heater is On The persistent switch takes the superconducting magnet into and out of persistence mode To exit persistent mode the MPS current ramps up to match the persistent current and the persistent switch heater coil heats the switch until it becomes normal non superconducting A delay allows magnet current to settle Then the magnet current ramps to a new value To enter persistent mode the MPS removes current from the persistent switch heater After a delay to allow the switch to superconduct the MPS current ramps down to 0 at a rate low enough to ensure the switch remains superconducting The magnet current then circulates in the superconducting loop formed by the magnet and the persistent switch Note To set PSH current see Chapter 6 Options And Accessories RUN Press either of the Data Entry up or down key to initiate Automatic Mode 3 4 Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 6 FUNCTION MENUS The MPS uses a
35. up to two terminator aU Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 4 Current Zero Commands Description The following MPS commands configure the various functions of the current zero features IMODE Input Returned Remarks VMODE Input Returned Remarks Zi Input Remarks ZI Input Returned Remarks ZIS Input Remarks ZIS Input Returned Remarks Remote Operation Current Programming Mode Query IMODE 0 if MODE switch is set to EXT or 1 if set to INT Returns one character plus up to two terminators When multiple MPS units are present the current programming mode of MPS No 1 is reported Voltage Programming Mode Query VMODE 0 if the V MODE switch is set to EXT or 1 if set to INT Returns one character plus up to two terminators When multiple MPS units are present the voltage programming mode of MPS No 1 is reported Programs Current Zero Value ZI current zero where current zero a value between 999 9999 Enter this setting after enabling ZI Status Control Bus inputs 4 places display rounds to 0 01 or 0 001 place If a ZI value is entered over the Control Bus status automatically turns ON Current Zero Value Query ZI A number between 999 9999 Returns nine characters plus up to two terminators Programs Current Zero Status ZIS status where status 0 to turn OFF the current zero or 1 to turn it ON
36. used with unit 2 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 Donot handle ESDS devices unnecessarily or remove them from their packages until actually used or tested SAFE HANDLING OF LIQUID CRYOGENS Two essential safety aspects of handling LHe are adequate ventilation and eye and skin protection Although helium gas is non toxic it is dangerous because it replaces air in a normal breathing atmosphere Liquid helium is an even greater threat because a small amount of liquid evaporates to create a large amount of gas Store and operate cryogenic dewars in open well ventilated areas WARNING e Liquid helium is a potential asphyxiant and can cause rapid suffocation without warning Store and use in an adequately ventilated area DO NOT vent the container in confined spaces DO NOT enter confined spaces where gas may be pres
37. with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Lake Shore Cryotronics Inc assumes no liability for the customer s failure to comply with these requirements Ground the Instrument To minimize shock hazard connect the instrument chassis and cabinet to an electrical ground The instrument is equipped with a three conductor AC power cable Plug this cable into either an approved three contact electrical outlet or 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 International Electrotechnical Commission IEC safety standards Do Not Operate in an Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Operating 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
38. 0 01 V A 0 01 V V 1 3 OPERATING CHARACTERISTICS CURRENT 10 mA 1 mA 10 mV 1 mV 0 01 Luss 0 1 Vmax 4mA 1mA 1mV 1mV 0 1 Imax 0 1 Vmax 10 mA 1 mA 10 mV 1mvV VOLTAGE 0 005 La 0 01 Vmax 40 uA ms 0 1 Imax 0 1 Vmax 0 005 Jun 0 05 Vmax 0 1 Imax 0 1 Vmax 10 Imax 10 Muss 1 100 mA 2 100 mV 1 100 mA 2 100 mV Many Lake Shore MPS operating characteristics ideally suit it for charge and discharge cycling of superconducting magnet loads These characteristics significantly differentiate a Lake Shore MPS from a conventional MPS Consider them when choosing the best MPS for a particular application 1 3 1 Lake Shore MPS Sets either positive or negative current and voltage values This true four quadrant operation significantly simplifies test procedures and system design by eliminating external switching or operator intervention to reverse current polarity The smooth continuous transition through zero current allows users to analyze samples at very small current increments as small as 1 mA about zero Power flow is bi directional Sink power energy stored in the magnet returns to the AC line instead of dissipating in an energy absorber The MPS either transfers power from the AC line to the magnet or from the magnet back to the AC line The MPS also tolerates AC line faults in the event of utility power failure it draws power from the charged load to maintain operation until uti
39. 0 to set IMAX to 50 Turn OFF the output current step feature during calibration Input and note the output current step status using ISTPS Send ISTPS0O to turn OFF output current step limiting Connect the DVM reading voltage across the OUT and OUT terminals Send VZER to inform the MPS of output voltage calibration and force output voltage to OV Verify a DVM reading of OV 0 1V Allow MPS output to settle for 2 minutes 10 Read actual output voltage from DVM Send the MPS the actual voltage using CALZ xxx xxxx If actual voltage is 0 0123V send CALZ 0 0123 The MPS determines the zero voltage calibration constant 11 Send VCAL5 to force output voltage to 5 volts Verify that the DVM reads 5V 10 Allow MPS output to settle for 2 minutes 12 Read actual output voltage from the DVM Send the actual voltage using CALPL xxx xxxx If actual voltage is 5 1234V send CALPL 5 1234 The MPS determines the positive voltage calibration constant 13 After the MPS determines the positive voltage calibration constant it automatically sets output voltage to the same value with the opposite sign Verify a DVM reading of 5V 10 Allow MPS output to settle for 2 minutes 14 Read actual output voltage from the DVM Send the actual voltage using CALMN xxx xxxx If actual voltage is 4 8766V send CALMN 4 8766 The MPS determines the negative voltage calibration constant 15 The MPS stores the zero positive and negative voltage calibration c
40. 4 5 EOI End Or Identify 6 DAV Data Valid 7 NRFD Not Ready For Data 8 NDAC Not Data Accepted 9 IFC Interface Clear 10 SRQ Service Request 11 ATN Attention 12 SHIELD Cable Shield 13 DIO5 Data Input Output Line 5 14 DIOG Data Input Output Line 6 15 DIO7 Data Input Output Line 7 16 DIO8 Data Input Output Line 8 17 REN Remote Enable 18 GND 6 Ground Wire Twisted pair with DAV 19 GND 7 Ground Wire Twisted pair with NRFD 20 GND 8 Ground Wire Twisted pair with NDAC 21 GND 9 Ground Wire Twisted pair with IFC 22 GND 10 Ground Wire Twisted pair with SRQ 23 GND11 Ground Wire Twisted pair with ATN 24 GND Logic Ground Figure 5 3 IEEE 488 Interface Connector Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 5 7 SERIAL INTERFACE CABLE AND ADAPTERS To aid in Serial Interface troubleshooting the figures below provide wiring information for the cable assembly and the two mating adapters TxD __ YELLOW Gnd GREEN Gnd RED RxD BLACK 123456 9G rpETHL C MPS 5 4 eps Figure 5 4 Model 2001 RJ 11 Cable Assembly Wiring RJ 11 RECEPTACLE Figure 5 5 Model 2002 RJ 11 to DB 25 Adapter Wiring Not Used RECEPTACLE Figure 5 6 Model 2003 RJ 11 to DB 9 Adapter Wiring 5 10 Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTE
41. 647 Returns nine characters plus up to two terminators Output Summary Query IV IOUT VOUT STB I MODE V MODE Returns twenty seven characters plus up to two terminators OVP Input Returned Remarks RES Input Returned Remarks RI Input Returned Remarks Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Overvoltage Quench Protection Circuit Status Query OVP 0 if the circuit is inactive or 1 if it is active One character plus up to two terminators are returned Resolution Query RES 0 for low resolution or 1 for high resolution This command maintains compatibility with older MPS versions Remote interface operation does not change since the remote resolution is already to the 0 0001 place Returns two characters plus up to two terminators Remote Inhibit Status Query RI 0 if the remote inhibit is inactive or 1 if it is active One character plus up to two terminators are returned VOUT V Output Voltage Query Input Returned Remarks VSET V Input Remarks VSET Input Returned Remarks 4 12 VOUT or V A number between 0 and 5 000 V 620 0 and 30 000 V 622 623 or 0 and 32 000 V 647 Returns nine characters plus up to two terminators Enter Compliance Voltage VSET voltage or V voltage where voltage a value from 0 and 5 000 V 620 0 and 30 000 V 622 623 or 0 and 32 000 V 647 The ini
42. E 488 Interface Connechor nsten tnnt Enn 5 9 5 7 Serial Interface Cable and Adapters ttnt nn nn nnnten nnen n ent 5 9 6 OPTIONS AND ACCESSORIES eecsccccsstscicccececessanectecccvesudescenteeneeeeuceescnectentevessdueceueateceversetneneddereeveesecetees 6 1 6 0 Ge eralis ien e eee ee a ee ed 6 1 6 1 Model 6224 IEEE 488 Serial Interface 6 1 6 2 Model 6226 6476 Liquid Helium Level and Gaussmeter Input Card 6 1 6 2 1 Hall Sensor Mounting Considerations Models HGCT 3020 and HGCA 3020 eee 6 2 6 2 2 The Model MSA 410 and MST 410 Hall Gensors 6 3 6 2 3 ele Ee E 6 3 6 2 4 Installation EE 6 3 6 2 5 Ebene Ee ee gaat we meee eege 6 4 6 2 51 LHe Level Operation ec daii eege eege eh 6 4 6 2 5 2 Field Probe Setting and Calibration 0 0 00 ccc ecceeeeeeeneeeeeeeneeeeeeneeeeeeaeeeeeeaeeeeeenaeeeeesnaeeeseaes 6 5 6 2 6 ee ee TEE 6 5 6 2 7 Model 6226 6476 IEEE 488 Remote Operation Commande 6 6 6 3 Model 6228 and 6228 8MUX Persistent Switch Heater Output 6 9 6 3 1 peter cs teres pein ee tats s ea Eege ee t 6 9 6 3 2 Model 6228 Operation 6 9 6 3 3 Model 6228 8MUX Operation sssssessknnnseesritrtnnsttsttttttnnstttt ttrt rnnr at ttrt EnEn nent rE EnEn nn nene Ennen 6 10 6 3 4 PSH Card Voltage Constraints eaaessseessiinesnneeiiinesinnnessnnandinnnaatannaniandaanaaddnaaneandunaaaannaaaaaa 6 10 6 3 5 Model 6228 Remote Operation Commande ssssssessnssssseirtrrretestttrrnntnnsttnnnnns ntt nnnn nennen ent 6 11 6 4 Model 6228 2
43. Faults Only action taken is Step Reset Mainframe Control Bus Operation
44. HP 3457A or equivalent d A computer with a RS 232C serial interface e LSCI Model 2002 RJ 11 to DB 25 adapter or Model 2003 RJ 11 to DE 9 adapter depending on the computer serial output connector Turn OFF and unplug the MPS before configuring it for calibration Configure the Control Bus Serial Interface for RS 232C Operation See Paragraph C4 0 Connect output to a computer using a modular cable or if equipped use the IEEE 6224 card Connect current monitoring shunt and load resistor in series to OUT and OUT terminals Enable MPS calibration Locate rear panel CAL AND ID switches and turn ON up switch 8 Verify that both MODE switches in the INTernal up position 6 Plug the MPS in turn it ON and allow it to warm up for one hour NOTE To terminate calibration at any time send CALDN Cycle MPS power to recover calibration constants present prior to calibration initiation Calibration determines a zero positive span and negative span digital calibration constant for both current and voltage Enter calibration constants with extreme caution If a constant is entered incorrectly terminate calibration with CALDN and re start the sequence 7 When calibrating current the MPS forces ISET to calibration current When calibrating voltage the MPS forces VSET to calibration voltage and ISET to IMAX Set IMAX to equal or greater than calibration current Input and note the IMAX value using IMAX For this calibration send IMAX 5
45. If RAMP ENABLE is ON the current or computed field ramps to the new setting at the displayed RAMP RATE If RAMP ENABLE is OFF the current or field changes to the new value immediately or to the value that causes MPS voltage COMPLIANCE However it is not recommended to operate the MPS with RAMP ENABLE OFF it may cause a magnet quench see Forward COMPLIANCE Read only Compliance Setting Change the COMPLIANCE voltage in the INSTRUMENT SETUP screen See Paragraph 3 6 1 4 RAMP RATE Ramp Rate Setting Exceeding the maximum rated magnet voltage or current ramp rate may damage the magnet Users may configure the MPS to limit the voltage by adjusting the compliance If RAMP ENABLE is ON RAMP RATE controls the rate at which the magnet current reaches the current setpoint as long as the MPS does not go into compliance See Paragraph 3 6 1 4 NOTE To pause or restart a ramp press either the Data Entry up or down key To abort a ramp press Esc 3 2 Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual The magnet manufacturer supplies the inductance of the magnet maximum ramp voltage and maximum current ramp rate The relationship for these parameters is given by the equation Vmax gt L di dt where Vmax rated maximum magnet ramp voltage in volts L magnet inductance in henrys and di dt maximum magnet current ramp rate in amps second To set the Magnet Ramp Rate for manual PSH control or no PSH
46. Magnet Power Supply User s Manual High AC HI AC Detected Output Inhibit Any time the AC line rises above 120 of the When the red Output Inhibit button is pressed the nominal line selected the MPS turns off the front MPS displays panel circuit breaker and enters AC Loss Mode AU OUTPUTS This halts excessive utility voltages to internal circuitry If this occurs on power up the MPS turns A off the front panel circuit breaker and displays ABALJ 1 999A ROUTERIT IHH I STEP Limit Exceeded When the user attempts to change the current setting 2 more than the GE limit setting the MPS si Overtemperature Detected If the MPS detects internal over temperature or other internal fault it activates the OVP circuit turns off the front panel circuit breaker and then turns itself off OVP stays active until it completely discharges the load If the heat sink temperature exceeds 95 C 203 F the MPS displays Caution Persistence Is Off Heater Is On When the user attempts to start Automatic Mode with persistence Off the MPS displays CALITIORN Rail Fault Detected Excessive DC rail voltage unable to return power to the utility or some other internal fault causes the MPS to display Caution Same Magnet Start and End Current To enter an automatic PSH cycle the magnet start and end current must be different If they are the same the MPS ee PSH Current Not The Same
47. Manual Mode ssssssseseesseressesnsserrssttrrssttrrssttnrssttntssttnnsstentssttnnnntennnsten nnt 3 2 3 4 Normal Display for Manual PSH Control 3 3 3 5 Normal Display for Automatic PSH Control 3 3 3 6 Function M nuS isi sciiret he er ee ENEE aden ap ee inde ne nae 3 5 3 6 1 Function Memes ai da lie en as deal eee eee es 3 5 3 6 1 1 Automatic Mode Manual Mode 3 5 3 6 1 2 Interface Setup Screen 2 ccc ceceeeccccce cece eeeeeeaeeeceeeeeceeeeaaneeeeeeeesacsaeaeeeeeeeeeseecaeaeeeeeeeeeeeeaees 3 5 3 6 1 3 Step Limit Zero Screen snsssneneenosenennt tt teetttr nn ntteettttn tans teettttn tannar tnnn nnne teennn nnmnnn nenen nn 3 6 3 6 1 4 Instrument Setup Screen eccccccceceeeeeeeeecece cece ee eeeeceaeeeeeeeeeecaacaeceeeeesesennanaeeeeeeeeneenaees 3 6 3 6 2 Function Meng 2 ee Sa eed ege 3 7 3 6 2 1 Outputs Only Screen cic cee it eed detec ent des fei REENEN EEN REENEN ENEE 3 8 3 6 2 2 LHe LeVel est ieee fool lie fee aaa de ee cd dade ee a a ea ee 3 8 3 6 2 3 Eiere cei ei genie atin AE a ad ea a ea 3 8 3 6 2 4 PSH Setup EE 3 8 3 6 3 Function Menu EE 3 8 3 6 3 1 Delays Setup Gcreen 20 KEVEd KREE ENER tended a A ETEA S A 3 8 3 6 3 2 Delays Setup Screen with Dithering 20 00 eee ceeeeeeenee tees tenets eeeaeeeeeeaeeeeesaeeeeeenaeeeeeeaes 3 9 3 7 Manual Persistence Control Example sssssssnnenseeetinreeestttrtntstesttttnrnnstrrtttnn nennt tenn nnns eene ee nn 3 9 3 8 Automatic Persistence Control Examp
48. N Q and press a Data Entry up down arrow key That line of the display changes to CALIBRATING MIN Q After measurement the display updates the minimum resistance in line 3 and the display returns to that shown above CALIBRATE Q inch ZS or CALIBRATE Q cm Measures the Level Sensor resistance per unit length The resistance per unit length is a function of temperature The effective value can be determined from the value measured at a more convenient temperature Figure 6 1 and Table 6 2 show the resistance values as a function of temperature of a NbTi filament The procedure described below measures the resistance per unit length at room temperature Take the level sensor out of the liquid and allow its temperature to stabilize Move the cursor to CALIBRATE Q inch and press a Data Entry up down arrow key That line of the display changes to CALIBRATING Qlinch cm After measurement the display updates the Q inch Q cm in line 4 and the display returns to that shown above NOTE If the resistance is too large the value is not updated In that case use a lower temperature or an ohmmeter to measure the resistance Options amp Accessories ss i lt i sSsSS S Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Look up the Rocco in Table 6 2 at the temperature of the sensor during measurement Use the equation R Table 6 2 NbTi Filament Resistance Values m R Q i 2 egecrive x ur active T
49. NG AND UNPACKING The MPS ships in a special cardboard box with integrated forklift skid openings Do not stack anything on top of the MPS box Upon receipt set the box on a level surface with the pallet side down Inspect the shipping container for external damage Make all claims for damage apparent or concealed or partial loss of shipment in writing to Lake Shore within five 5 days from receipt of goods If damage or loss is apparent notify the shipping agent immediately Cut off the plastic strapping and lift off the lid Locate the MPS packing list and use it to check for receipt of all components cables accessories and manuals Inspect each item for damage Use two people to lift the MPS Retain internal packing material and box for reshipment Fill out and send the warranty card If there is freight damage to any instruments promptly file proper claims with the carrier and insurance company and notify Lake Shore Cryotronics Notify Lake Shore of any missing parts immediately Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment See the standard Lake Shore Cryotronics Inc Warranty on the A Page immediately behind the title page 2 2 MPS MOUNTING After unpacking the MPS and verifying receipt of all packing list items mount the instrument in a suitable location The MPS ships with feet installed and is ready for use as a bench top instrument The MPS also ships with 19 inch rack mounting
50. PIBO Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address T Select the primary GPIB address by Secondary GPIB Address a using the left and right arrow keys Timeout setting This address is used to compute the Terminate Read on EOS talk and listen addresses which Set EOI with EOS on Writes identify the board or device on the Type of compare on EOS i GPIB Valid primary addresses range EOS byte from 0 to 30 OOH to 1EH Send EOI at end of Write Adding 32 to the primary address System Controller forms the Listen Address LA Assert REN when SC Adding 64 to the primary address Enable Auto Serial Polling forms the Talk Address TA Enable CIC Protocol Bus Timing 500nsec EXAMPLE Selecting a primary Parallel Poll Duration Default address of 10 yields the following Use this GPIB board 10 32 42 Listen address Board Type 10 64 74 Talk address Base IO Address F1 Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board National Instruments DEV12 Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address T Select the primary GPIB address by Secondary GPIB Address a using the left and right arrow keys Timeout setting This address is used to compute the Terminate Read on EOS talk and listen addresses which Set EOI with EOS on Writes identify the board or device on the Type of compare on EOS i GPIB Valid primary addresses range from 0 to 30 OOH to 1EH Send EOI at end of Write Adding 32 to the primary address
51. Persistent Switch Heater Output 6 12 6 4 1 Model 6228 2 Remote Operation Commandes 6 13 6 5 e 6 14 APPENDIX A UNITS FOR MAGNETIC PROPERTIES c ecceeeeeeeeeeeeeeeceeeeeseeeseaneeeeeeeeseesseaneeseeeens A 1 APPENDIX B MAINFRAME REMOTE OPERATION 00 cccc seecceeeeeeeeeeeeeeeeeeeeeseeseaneeseeeeeseeseeneeeeeeens B 1 B1 0 ET B 1 B2 0 Control Bus Serial Interface Gpechflcations eenn te ne teetttnntnnretrtttnn nenet nnnnnn nenene B 1 B3 0 Control Bus Serial Interface Connector 2c eeceeeccece cece eeeeceae cece ee eesecaeaeeeeeeesecenseeeeeeeeeeeeiees B 1 B4 0 Control Bus Serial Interface Configuration eccccceeeceeeeeeeeeeeeeeeeeeseeeeeeeseeeeeeeseenaeereeeaeees B 2 B5 0 Selecting the Control Bus Serial Interface Address B 2 B6 0 Control Bus Serial Interface Operation B 3 B7 0 Control Bus Serial Interface Sample Program B 4 Table of Contents Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual LIST OF ILLUSTRATIONS Figure No Title Page 1 1 Four Quadrant Power 2050 ie aad aed ENEE cess ened die eee Eden 1 4 1 2 Comparison of Old and New MPS DesignS ccc cceeeeeeeeeeeneeeeeeeaeeeeeeeeeeeeaaeeeseeaeeeeeeaeeeeeenaeeeeeeaas 1 5 2 1 RI FLT ON and OVP Connections oesnannnnuessnsrnrnrinessrrrrrrrrssrsnnrnrirrssnsnnrrriorssnnrnrrerosrennrnrreeeseeenn 2 4 2 2 Analog Monitoring Programming A Remote Sense Connections sseeeeseeeeeesereseerrereerrreerreseeen 2 5 2 3
52. Power Supply User s Manual 3 2 POWER UP Read and follow instructions in Paragraphs 2 1 2 4 3 and the Forward safety recommendations before applying power to the MPS Do not connect the MPS to the magnet yet Short the output terminals together with a 4 gauge or larger cable to protect the magnet against incorrect configurations Turn on the MPS It requires approximately 2 seconds for initialization Initially all front panel annunciators come on and the alarm sounds for a short time Within 1 second the Fault and Persistent Switch Heater On annunciators and the alarm turn off If the MPS detects a high or low AC line fault it blinks the front panel Fault annunciator and turns off the input circuit breaker If this occurs verify that the AC source matches the line voltage listed on the MPS rear panel Initially the entire display clears and the alarm sounds for a short time The MPS initializes itself and displays the model identification The Normal Display screen appears with a blinking asterisk indicating each update when the unit is in normal operation Depending on the existence of the PSH Option Card and the mode of operation the MPS displays one of three possible Normal Displays on power up one for Manual Mode no PSH Option Card one for Manual PSH Control or one for Automatic PSH Control The factory preset is the Normal Display for Manual Mode but the MPS remembers the last PSH mode selected at power down and powers up in tha
53. R 6 OPTIONS AND ACCESSORIES 6 0 GENERAL This chapter covers MPS options and accessories Model 6224 IEEE 488 Serial Interface installation Paragraph 6 1 Model 6226 6476 Liquid Helium Level and Gaussmeter Input Card Paragraph 6 2 Model 6228 Persistent Switch Heater Output Paragraph 6 3 Model 6228 2 Persistent Switch Heater Output Paragraph 6 4 and Accessories Paragraph 6 5 6 1 MODEL 6224 IEEE 488 SERIAL INTERFACE This option interfaces with a Customer supplied computer equipped with a compatible IEEE 488 or Serial Interface It accesses operating data and stored parameters and remotely controls front panel operations Only one Model 6224 is required for multiple MPS installations See Chapter 4 for MPS remote operation Installation Procedure WARNING e This procedure is intended for trained service personnel who understand electronic circuitry and the hazards involved Do not attempt this procedure unless qualified e To prevent shock hazard turn off the instrument and disconnect AC line power and all test equipment before proceeding 1 Turn unit OFF and disconnect power cord 2 Remove the two screws of the blank option cover plate to the far left of the MPS rear panel and remove the cover plate If another option exists in this slot remove it The IEEE cable should point down Install the option in the far slot to avoid IEEE cable interference with the power cord 3 Slide the Model 6224 board into the MPS with the
54. Remote Sensing Connections snie iieii ieia EEN EA A EE 2 6 2 4 Typical Multiple MPS Connections for Two MPS Untts 2 8 3 1 MS Front Panel tee a a a a dnl i a GEES 3 1 3 2 Typical Automatic Mode Cycle nesnesini iiini iai i E E AEEA A AA d 3 10 4 1 Typical National Instruments GPIB Configuration from IBCONF ENEE 4 6 4 2 Serial Interface Adapters tnne trrt Etn ERASE EE AEARACAEeE EEEn EREE s EEan ne nnen nn En 4 7 5 1 Rear Panel Connectors ae eaa a aeaa ae a daara aa aa a a aa e a aaa AAA E RLS 5 8 5 2 Serial Interface Connector 2c cece cece cece ee eeeeeeae cece eect eee aeaeceeeee ee saaeaeaeceeeeeeeseeaeaeeeeeeeseeeeieeeeeeeeetes 5 8 5 3 IEEE 488 Connector Nee aiea eel cadena nel eee toe eke ea ee ee 5 9 5 4 Model 2001 RJ 11 Cable Assembly Wiring ccceeeeeeeeeeeeeeeeseeeeeeeseneeeeeeeneeeeeseneaeeeseneaeesenaeeetenaaees 5 9 5 5 Model 2002 RJ 11 to DB 9 Adapter Wimg eee ceeeeceeeeeereeeeeeeeeeeeseeeeeeeeeeeaeeeseneaeeeseeeaeeeseeaeeeeeeaaes 5 9 5 6 Model 2003 RJ 11 to DB 25 Adapter VWimg 5 9 6 1 NbTi Filament Resistance Chart 6 6 Table No Title Page 1 1 Model 620 622 623 Input CUrrent ei aa e e aa aeaa as Eaa a ea a a aa aaea aaea 1 3 1 2 lee Hellege EE 1 3 1 3 Model 620 622 623 DC Output Specifications ecccceccceceeeeeenecceceeeeeeeeeeeaeceeeeeeesesaeaeeeeeeeeeteenaees 1 3 1 4 Model 647 DC Output Specifications ccccccccecceeeeeece cece eeeeeeceaeaeceeeeeseeeaaeaeeeeeeesesenaeeeeeeeeeesaees 1 3 2 1 Lo
55. ST 410 gaussmeter probes are used with the Model 6476 Lake Shore offers a ten foot extension cable Model MPEC 410 10 6 2 3 Connections The Model 6226 6476 has one rear panel 9 pin connector to interface with the Table 6 1 Model 6226 647 level and field probes See Table 6 1 SE Ge S Connections The 6226 6476 Liquid Helium Level and Gaussmeter Input Option is factory Field Current installed if ordered with a MPS or may be field installed at a later date For Field Voltage field installation use the procedure below Field Voltage WARNING Field Current Shield e This procedure is intended for trained service personnel who Level Current understand electronic circuitry and the hazards involved Do not Level Voltage attempt this procedure unless qualified Level Voltage To prevent shock hazard turn off the instrument and disconnect AC Level Current line power and all test equipment before removing cover 1 2 3 4 5 6 7 8 9 1 Turn off the MPS and disconnect the power cord 2 Locate the Optional Plug In Board Slots on the MPS rear panel Loosen the two screws that secure one of the blank cover plates and remove the cover plate 3 Slide the Model 6226 6476 board into the MPS with the board handle towards the bottom of the MPS Tighten the two screws that secure the board to the MPS rear panel Options amp Accessories eses lt i s B Lake Shore Model 620 622 623 647 Magnet Power Supply
56. Shielding Grounding andNoise tanet tenn nnns enerne ennn 2 4 2 5 3 MPS Remote Inhibit and Fault Indicator Connections cccccccececceceeeeeeeeeneeeeeeeeeeeeees 2 4 2 5 4 AG Om Helle e EE 2 4 2 5 5 OVP ConneCtiOn EE 2 4 2 5 6 MPS Analog Current and Voltage Monitoring Connechons cc ccceeeeeeseeeeeeeeeneeeeeeeaeees 2 5 2 5 7 External Current Prooramming 2 5 2 5 8 Remote Sense Conpnechons cess aaaeeeceeeeeseeeanaeeeeeeeeeseeenaeeeeeeeeeeess 2 5 2 6 Multiple Auto Parallel Setup cececcecccccceeeeeeeeneeceeeeeeececeaaaeceeeeeeseceeaeeeeeeeseseccasaeeeeeeeseseeaees 2 6 2 6 1 Multiple MPS Remote Inhibit Mode cccccceceeceececeeeeeeeceecaeceeeeeeeseccneaeeeeeeeeetecaeeeeeeeeeeees 2 8 2 7 Post Installation Instructions ccccccceceeeeeeeecaeceeee cece eaaececeeeeesecaaaeceeeeeeesecsnaeeeeeeeenseesiaeees 2 9 2 8 System Shutdown and Repackaging for Storage or ShHiPMeNt ce eeceeeeeeeeeeeeeeeeeeeeeeees 2 9 2 9 Returning Equipment to Lake Ghore nennen nenn 2 9 3 OPERATION r ert aee pT a a a shaded add evens r a aa Aa r Aaa EAA Aaaa a aaaea aaan TaN paaria a EaR 3 1 3 0 Eet aseene cee aie ela a cadet ee 3 1 3 1 The MPS Front Rapnek11gpgeg eege EE Egger a e a eede ar eee 3 1 3 2 Power Hee TE ee ea toate a a hal tad a a ele 3 2 Table of Contents Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 3 3 Normal Display for
57. The heater turns on and the lt ON gt changes to lt OFF gt If it does not change check the heater wiring and or heater current specified If an error message OUT OF CMPL appears then the heater power supply is at its voltage limit If so check the wiring and or change the heater current At this point the MPS and magnet currents are 20 amperes Select a suitable ramp rate for current in the magnet and enter the desired current 30 amperes into the setpoint setting The MPS and magnet current ramp to 30 amperes Using the cursor keys move to the last line PERSISTENCE lt ON gt and press a Data Entry up or down arrow The heater turns off and the lt OFF gt changes to lt ON gt Now ramp the MPS to zero current The magnet is in persistence at 30 amperes Figure 3 2 illustrates the process just described The same process can be done automatically See Paragraphs 3 5 3 8 3 8 AUTOMATIC PERSISTENCE CONTROL EXAMPLE 1 Enter the Instrument Setup screen and set the Compliance voltage limit which the MPS cannot exceed See magnet manufacturer information to determine this value Once set the MPS retains the value in non volatile memory as the default value Return to the Automatic Mode display Operation 3 9 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 2 Enter these parameters in the Automatic Mode Screen MAG START Magnet Start Current only if LAST END is unknown For this example we ass
58. Type Lake Shore Model MST 410 transverse or Model MSA 410 axial Number of Inputs 1 four lead measurement Nominal Excitation 1 mA Probe Magnetic Sensitivity 20 mV mG 50 Nominal Field Range Nominal 20 kG 20 mV kG Input Voltage Resolution gt 0 04 mV out of 0 4 volts full scale Sample Interval Probe excited continuously amp read when level is not Display Resolution 0 01 kG 0 001T Electronic Accuracy 1 of full scale Contact Lake Shore for details on a variety of Hall Probes and Sensors 6 2 1 Hall Sensor Mounting Considerations Models HGCT 3020 and HGCA 3020 The Lake Shore Model HGCT 3020 Transverse and Model HGCA 3020 Axial Cryogenic Hall Sensors are four terminal solid state devices that produce output voltage proportional to the product of the input current magnetic flux density and the sine of the angle between the field vector and the plane of the Hall generator The active area of the Model HGCT 3020 Transverse Hall Sensor is approximately 0 04 inch in diameter with the center indicated by a cross on one face of the package When the control current is applied with the red lead positive with respect to the black lead and the magnetic field is perpendicular into the face of the probe with the cross on it the Hall voltage is positive at the blue lead with respect to the yellow lead A reversal in the mechanical orientation or in the direction of either the magnetic field or the control current results in a
59. User s Manual 6 2 5 LHe Level Access liquid helium level and field monitoring from the MPS front panel Press Function Menu and then Next Menu to display Function Menu 2 If the Model 6226 6476 Option is not present lt NP gt appears next to LHe LEVEL and FIELD and associated function keys are ignored 6 2 5 1 LHe Level Operation Press the LHe LEVEL Function key to display the Liquid Helium Level screen The Menu window returns to display Output values The cursor up and down keys move the line indicator The icon indicates parameters changed only with the Data Entry up and down arrows When there are lt ON gt or lt OFF gt indicators the Data Entry up and down arrows change the status if they are the first data entry keys used READING lt OFF gt or lt ON gt Level Reading Status The Data Entry up or down arrow initiates a level reading UNITS in E or cm M Level Units The Data Entry up or down arrow scrolls through the available units inches English percent or centimeters Metric NEXT RDG 00 00 Time in Hours Minutes The Time to Next Reading PERIOD 00 00 Time in Hours Minutes Level Sample Period A time of 00 00 indicates a continuous reading 20 second period 5 seconds for level reading Use any numeric entry mode to change the value Period limit is 23 59 ALARM 0 0 Reading and lt OFF gt or lt ON gt Level Alarm and Alarm Status The Data Entry up or down arrow toggl
60. User s Manual Model 620 622 623 647 Magnet Power Supply Now Featuring AUTOMATIC MODE Model 620 50 A 5 V Model 623 155 A 30 V Model 622 125 A 30 V Model 647 72 A 32 V akeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA E Mail Addresses sales lakeshore com service lakeshore com Visit Our Website www lakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Rev 1 2 P N 119 001 9 April 1999 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual LIMITED WARRANTY Lake Shore Cryotronics Inc henceforth Lake Shore the manufacturer warrants the instrument to be free from defects in material and wor
61. ace specific commands not supported by the serial interface When programming a Mainframe from the serial interface consider the notes below See Chapter 3 for additional notes on commands e The control bus serial interface transmission mode asynchronous half duplex format 10 bits per character 1 start 7 data 1 odd parity and 1 stop and baud rate 9600 are all fixed at the factory as outlined previously in the Serial Interface Specifications e The control bus cannot be used for remote interfacing if a Multiple Mainframe MMF configuration is used In MMF mode the Control Bus is used for Mainframe to Mainframe communications e End of string terminators are fixed at CR LF e A query must be added to the end of a command string if the Mainframe is required to return information e Chain commands together with a semi colon a comma or a blank Some programming languages do not allow separators other than a blank e At 9600 baud each character takes about 1 millisecond to transmit Some host computers DMA serial interface access The program must allow for the transmission time delay before looking for a query response e Characters received by the Mainframe are stored in a buffer After receiving the terminators the Mainframe stores any new parameters and responds to the query if requested The Mainframe requires about 100 milliseconds to store new parameters before receiving any more new commands s The Mainframe impleme
62. acy 0 to 10 KQ produces negative full scale to positive full scale 10 ba 3V current or voltage output 5 KQ is 0 current Analog Voltage Programming Accuracy o o Voltage input is 0 01 V A 0 01 V V 1 100 mA 2 100 mV Monitoring Output Accuracy Voltage output is o o 0 01 V A 0 01 V V 1 100 mA 2 100 mV Introduction 1 3 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Table 1 4 Model 647 DC Output Specifications SPECIFICATION Digital Programming Resolution Standard High Digital Programming Accuracy Digital Programming Repeatability Electronic Resolution Standard High Electronic Accuracy Display Resolution Standard High Stability Drift at 25 1 C Percent of full scale output change over 8 hours under constant line and load after a 30 minute warm up Ripple and Noise 10 Hz to 10 MHz at 1000 VA Temperature Coefficient Change in output per C after 30 minute warm up Source Effect Line regulation for any line change within the rated line voltage Load Effect Load regulation for a load change equal to maximum voltage in Constant Current Mode or maximum current in Constant Voltage Mode Analog Resistance Programming Accuracy 0 to 10 KQ produces negative full scale to positive full scale current or voltage output 5 KQ is 0 current Analog Voltage Programming Accuracy Voltage input is 0 01 V A 0 01 V V Monitoring Output Accuracy Voltage output is
63. ad Wire Lengths and Current Canach 2 3 2 2 RI FLT ON and OVbPConnechons onraad taenia redan aa aee adig kranie dakare da i rairirts 2 4 2 3 Analog Monitoring Programming and Remote Sense Connechons 0 cccccesceeeeeeseeeeeetteeeeees 2 5 2 4 Connections for a Two MPS Autoparallel Conftouraton 2 7 4 1 Sample Basic IEEE 488 Interface Program 4 5 4 2 Serial Interface Specifications ccccccccceceeceneececeeeeeeeenaece cess ee seceaeaeceeeeeeeseseaeceeeeeseeesieeeeeeeeetees 4 8 4 3 Sample Basic Serial Interface Program 4 9 5 1A Rear Panel Connector Definitions ccccceeececeenecceceeeeeteceaeceeeeeecsaaaeaeeeeeeesesecaeaeeeeesesessnaneeeees 5 8 5 1B Rear Panel CAL AND ID Switch Dettnttons cece ee eeeeeeeeeeeeeeseseceaeaeeeeeeeseessnineeess 5 8 5 2 Serial Interface Connector Definition cecececcecceceeeeeeeceec eee ee eeeeceaeaeceeeeeeeseccneaeeeeeeeeesecenaeeeeeeeees 5 8 5 3 IEEE 488 Interface Connector Definition cecececceceeeeeeeeeenee cece cece teceacaeeeeeeesesencasaeeeeeeesetssneeneees 5 9 6 1 Model 6226 6476 Connections ssssnssseeessnnnrensteetttttttsttettttntt ts ttetttnnnnanst ertt EnEn ES nen tEnn Ennen en nnen tent 6 3 6 2 NbTi Filament Resistance Values ceccccecceceeeeeeeeeeeaeeeeeeeeeeeaaaeaeeeeeeesececaaeaeeeeeeesesenceeeeeeeeneeaees 6 6 A 1 Units for Magnetic Properes o arencarou iina niai a eai aS a a aiae ai dA A 1 B 1 MPS Mainframe Control Bus
64. agraph 3 7 Setup the MPS software with the MPS output terminals shorted together as in section 3 2 This ensures that while the user learns MPS operation an inadvertent keystroke causes no damage to the magnet 3 1 THE MPS FRONT PANEL Figure 3 1 below shows the MPS Front Panel The up or down Display Cursor Control keys move the line indicator to the line containing a value to be changed Use either the Data Entry Keypad to enter the desired value or the up or down Numeric Entry keys to increment or decrement the value The Enter key accepts the update while the Esc key discards the change and returns to the prior value Move the cursor to a particular digit with the right and left Display Cursor Control keys and change it with the Numeric Entry keys DI akeShore Magnet Power Supply Display Screen G Data Entry Up and Down Keys Increment and decrement numeric values Pause Restart ramps or execute some functions Output Inhibit Key Display Cursor Control Keys Enter Key Accepts a change Power Indicator Fault Indicator Persistent Switch Heater Indicator Power Switch Display Function Keys Display Menu Selection Keys Data Entry Keypad m Do D p gt Escape Key Restores an old value and returns from a Function Screen to Normal Screen Also Aborts a ramp or automatic process SS Str Str TE F Interface Keys Figure 3 1 MPS Front Panel Operation 3 1 Lake Shore Model 620 622 623 647 Magnet
65. amming via the rear panel MODE switch When the MODE switch is in the INT position external current mode is disabled When the MODE switch is in the EXT position the external programming voltage is summed with the internal programming voltage Set the internal programming to zero for external programming only Apply an external voltage from Ip to m of 0 to 1 25 volts or use a 10 KQ potentiometer to control the output current over the entire range Make connections to rear panel detachable terminal block defined in Tables 2 3 and 2 4 and Figures 2 1 and 2 2 The MPS produces 100 A of output current for 1 V at the current programming input NOTE MPS protection circuits reduce the effect of open external programming leads An open external programming lead forces external programming voltage to approximately 0 volts 2 5 8 Remote Sense Connections Table 2 2 Analog Monitoring Programming and Remote Sense Connections TERMINAL LABEL DEFINITION V Output Current Monitor Voltage output from Im to GND M is 10 mV A Output voltage monitor Voltage output from Vm to GND M is 10 mV V Im 10 m 11 m Monitor and program ground GND m 2 Vp Not Used 13 Vs Not Used 14 Is 5 16 Is 17 S 18 S Current programming input voltage Voltage input from Ip to GND m produces 100 A V Voltage may come from a voltage source or from the center tap of a potentiometer connected from Is to ls
66. ay units from amps to field units To change Normal Display units move to the Field Enable line and toggle it ON Move to the B UNITS Field Units line and toggle the units between kG or Tesla Move the cursor to the KG A or Tesla A line and enter the magnet Field to Current ratio Usually the ratio is on the magnet data sheet If not call the magnet manufacturer The MPS now sets and displays magnet field in the desired units The Default is Field Enable OFF B UNITS kG or tesla Define B Field Units in kilogauss kG or tesla The Default is kG FIELD A kG A or tesla A Magnet Field to Current ratio Obtain this value from the magnet data sheet or calculate it from magnet manufacturer information The Default is 1 000 kG A 0 1000 tesla A 3 6 Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual IMAX SET 0 00 A to 50 00 A 620 125 00 A 622 155 00 A 623 or 72 00 A 647 Current Maximum Setting MPS current cannot exceed this setting The software allows no setting above these limits The rated maximum magnet current is the current above which magnet damage may occur Never exceed the rated maximum current IMAX is the maximum output current ISET is the constant output current The value for ISET cannot exceed the value for IMAX For example if the user sets IMAx to 1 A the MPS limits any constant output current in excess of 1 A to 1 A If the user increases Imax to 10 A and sets ISET to 1 A th
67. before changing MPS configuration 2 Determine which MPS to assign as MPS 1 and configure it as follows a Locate the CAL AND ID DIP switches on the rear panel Turn ON up position switches 1 and 4 Turn OFF down position switches 2 3 and 5 through 8 Switch 4 ON designates multiple MPS operation Switches 3 2 and 1 respectively OFF OFF and ON assign the MPS address as 1 Note that the CAL AND ID switch numbers are upside down as viewed from the rear panel Switch 1 is on the right and switch 8 is on the left Take care to use the correct switch numbers b Move the MODE switch to the INTernal up position Setup amp Connections Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual c Locate Communications Microprocessor CMP in the MPS rear panel The CMP is the module with two RJ 11 telephone jacks Loosen two screws securing CMP to MPS rear panel and slide CMP out Just inside the CMP front panel there is a set of DIP switches Verify that switches 5 6 and 7 are ON closed and switches 1 through 4 and 8 are OFF OPEN Switches 1 4 define the control bus as Serial RS 232C Switches 5 8 define the control bus as RS 485 multidrop Switch 8 terminates the bus for long communications loop runs Close switch 8 to terminate the control bus only if the MPS units are a significant distance from each other Replace the CMP 3 Configure the second MPS as MPS 2 a Locate the CAL AND ID switches on the
68. ble Setup amp Connections e B Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 2 5 2 Shielding Grounding and Noise For noise reduction tightly twist and shield the leads from the MPS to the magnet Connect the shield to the MPS chassis as shown in Figure 2 3 WARNING DO NOT place magnet leads in contact with other MPS system connections or metal parts In some instances the user s measurement leads may pick up noise from the magnet leads Although this common mode noise may affect the user s measurement it rarely affects the current in the magnet If the user s measurement is earth grounded some improvement is almost always possible by tying the OUT terminal of the MPS to earth ground either at the MPS chassis or if the user s system has one the common system earth ground point WARNING If the OUT terminal is tied to earth ground make certain the OUT cable from the MPS contacts no other earth ground point it forces the MPS output current into this other ground point If the other ground point is a small wire it may melt or catch fire 2 5 3 MPS Remote Inhibit and Fault Indicator Connections The MPS has a Fault Indicator Table 2 1 RI FLT ON and OVP Connections FLT output and a discrete are both interface independent 1 RI Remote Inhibit Active low TTL compatible input to and provide fault indication and 2 RI remotely force the output settings to 0 A and 1 V Also remote output shutdown
69. calibration Do not change unless probe is actually being calibrated mV kG XXX XXX Field Probe Sensitivity Each Hall Probe comes with a mV kG sensitivity Use any numeric entry mode to change the value from 0 to 999 999 ZERO RDG lt OFF gt or lt ON gt Field Probe Zero Reading Connect the Hall Probe and place it in zero magnetic field Press a Data Entry up or down arrow key to zero the probe 6 2 6 Level Sensor Calibration To enter or measure level sensor parameters select CALIBRATE SENSOR line 8 in the LIQUID HELIUM LEVEL screen Prior to this select a length of inches or centimeters not percent Units of length do not display on the calibration screen if percent is selected LENGTH 24 0 in or LENGTH 61 0 cm Level Sensor Length Use any numeric entry mode to change the value Allows values from 0 0 to 999 9 MIN Q 0 00 ohms Level Sensor minimum resistance in ohms If minimum resistance is known enter it directly with the Data Entry keys Otherwise measure it as shown below under SELF CALIBRATION CALIBRATE MIN Q Q linch 10 41 or Q cm 4 10 Level Sensor resistance per unit length If the value is known enter it directly with the Data Entry keys Otherwise it can be measured as shown below under SELF CALIBRATION CALIBRATE Q inch cm CALIBRATE MIN OS Measures the Level Sensor minimum resistance Connect the level sensor immersed in LHe to the active level sensor length Move the cursor to CALIBRATE MI
70. ceeded Query STEP 0 if the step limit has not been exceeded or 1 if it has been exceeded Returns one character plus up to two terminators Output Current Step Limit Status Reset STEPR1 Nothing When the output current step limit has been exceeded this command must be issued before normal operation can be resumed Remote Operation 4 3 6 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Computed Field Commands Description The MPS can also display Computed Field rather than current This is useful with Superconducting magnets because there is a linear relationship between the current and actual field to a reasonable degree of accuracy This feature is not to be confused with the field as measured with the Model 6226 Liquid Helium Level and Gaussmeter Input Card The commands and queries below allow users to calculate the same Computed field in the host computer as is displayed on the MPS front panel CFPA Input Remarks CFPA Input Returned Remarks CFUNI Input Remarks CFUNI Input Returned Remarks CFPS Input Remarks CFPS Input Returned Remarks Remote Operation Programs Computed Field Ampere Constant CFPA field ampere where field ampere is kG ampere or tesla ampere dependent on the computed field units Programs the kG ampere or tesla ampere constant used primarily in superconducting magnets Limited to 9 999 kG ampere 0 9999 tesla Value is rounded to
71. ches between operation as a current source and limitation by the compliance voltage The MPS operates most smoothly as a current source As such current ramp rate is limited by NM lt vat where NM max magnet current ramp rate in amperes second Vse MPS compliance voltage and L magnet inductance in henrys In a multiple MPS configuration each MPS must operate in current mode If one unit operates in compliance mode while the others operate in current mode uneven distribution of the current load results Though compliance voltage is user defined if operation above safe diode voltage is a possibility Lake Shore can limit the hardware output voltage range and OVP to a safe level for the magnet Example 3 volts maximum output voltage limit with an OVP setting of 7 to 9 volts assuming this voltage is below the diode forward voltage at 4 2 K Return the MPS to the factory for this hardware modification To set the compliance voltage move to the COMPLIANCE line and enter a compliance voltage less than the maximum voltage for both the magnet and the magnet protection diodes Software also automatically limits MPS output power to 1000 VA 622 amp 623 or 2000 VA 647 by adjusting the voltage For example if the user sets current to 0 amps and compliance to 30 volts then changes current to 100 amps the MPS software automatically sets compliance to 10 volts 3 6 2 Function Menu 2 Screen To display Function Menu 2 shown on the r
72. ches complicate high power cabling requirements increase chances of introducing output current instabilities and require time to reverse leads Manual lead reversal introduces discontinuity at the current reversal point A discontinuous transition through zero current may require a small external supply for near zero current analysis Utility power failure in a conventional supply generally results in a magnet quench 1 3 2 Lake Shore MPS Maintains a high stability low noise current regulated output Digital setting and monitoring electronics and computer interfacing integrate into power management and precision analog control circuitry This integration maintains high output stability and repeatability Extensive output filtering and noise cancellation circuitry keep MPS output noise very low The MPS front panel graphic display allows continuous display of output current and voltage while setting parameters from the menu driven keypad In addition to the front panel and remote interface programming the MPS includes analog inputs and outputs for setting and monitoring operating parameters The MPS requires only 7 inches of rack space Conventional MPS Some use a compliance limited output with current monitoring to charge the magnet Others require output current to drive against the output current limit to prevent output current drift Most use multi turn potentiometers and digital or analog panel meters for front panel current an
73. connect to the host 5 TransmitData B computer 6 No Connection Ne Connection Mainframe Control Bus Operation BA Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual B4 0 CONTROL BUS SERIAL INTERFACE CONFIGURATION Configure the control bus serial interface for either RS 232C or RS 485 communications with DIP switches on the Communications Processor Board CMP The CMP plugs into the Mainframe rear panel The standard control bus serial interface configuration is RS 485 Use the procedure below to change or verify the serial interface configuration 1 Turn off Mainframe and unplug the power cord Terminated Unterminat d x l 2 Loosen the two screws that secure the CMP to Configuratio e RS 485 RS 485 the rear panel and slide the CMP out a Ee a 5 ose 3 Locate and configure the control bus serial interface DIP switches as defined in the table to the right The DIP switches are just inside the CMP front panel Switches 1 4 define the interface as RS 232C Switches 5 8 define the dE 6 Open Closed Closed activates 100Q bus termination for long serial H interface runs For RS 485 terminate extremely long main lines at the furthest point from the 8 Open Closed Open host Limit main line length to under 4000 feet and multiple short stub lines from the main line Mainframe to Mainframe to under 50 feet A typical RS 485 configuration runs the main line from the host to one of the firs
74. control move to the RAMP RATE line and enter a ramp rate less than the magnet s maximum ramp rate In manual PSH control the MPS uses the RAMP RATE value to ramp both the magnet current and the persistence switch current To activate ramping move to the RAMP ENABLE line and toggle RAMP ON Upon entering a new current set point the current ramps at the entered ramp rate RAMP ENABLE lt ON gt or lt OFF gt RAMP ENABLE ON causes current to ramp at the specified ramp rate when the current field is changed Turn RAMP ENABLE OFF to force the MPS to step immediately to the new CURRENT or FIELD SETTING Move to the RAMP ENABLE line and toggle the RAMP ENABLE OFF 3 4 NORMAL DISPLAY FOR MANUAL PSH CONTROL To the right is the default start up Normal Display screen for an MPS with a PSH option card installed and Manual Persistence Control Mode selected To change to Automatic Persistence Control Mode press the MENU key and select Automatic Mode from Function Menu 1 For Automatic Persistence Control Mode see Paragraph 3 5 The Normal Display for Manual PSH Control functions the same as the Normal Display for Manual Mode with the exception of the option below PERSISTENCE lt ON gt or lt OFF gt Persistence Mode Status If Persistence Mode is On the PSH heater is Off If it is Off the PSH heater is On Note To set PSH heater current see Chapter 6 Options And Accessories 3 5 NORMAL DISPLAY FOR AUTOMATIC PSH CONTROL To the right
75. d CALMN 48 7655 The MPS determines the negative current calibration constant 23 The MPS stores the zero positive and negative current calibration constants then sets output current to 0 Verify a DVM reading of OV 0 00005V before continuing the calibration 24 Use IMAX and STPS to restore IMAX and output current step to Step 7 values 25 Turn off MPS and disconnect calibration loads 26 Restore original Control Bus Serial Interface settings 27 Disable MPS calibration Turn OFF down CAL AND ID switch 8 5 4 PERFORMANCE TEST Performance tests verify proper MPS operation into a resistive load without testing all specified parameters The tests include no troubleshooting information but can provide information that may localize faults If any tests fail contact authorized service personnel WARNING For service return MPS to Lake Shore or a factory representative Lake Shore Cryotronics Inc cannot be held liable for injury or death of personnel attempting unauthorized MPS repairs Test Equipment Required 1 Current monitor shunt 100 mV output rated at 150 A Manufacturers typically stock this shunt value If a different value is used adjust readings given in the procedure 2 Digital Volt Meter DVM capable of reading DC voltage from 100 mV with 0 1 mV accuracy to 35 V with 0 1 V resolution Performance Test Procedure The test procedure includes both front panel and remote operation Execute the performance tests in t
76. d compliance Low Noise High Stability Current Regulated Output Analog Current Programmer Analog Voltage Programmer Analog Programmed Power Supply Current Reversal Energy Absorber DVM Current Monitor DVM Monitor e Magnet Load Now Replaced by Lake Shore MPS True Four Quadrant Bi Directional Power Flow az eegend Magnet Load Figure 1 2 Comparison of Old and New MPS Designs voltage setting The elegance and repeatability of keypad entry is not available There is no digital setting or monitoring integration in the output control circuitry Most achieve computer interfacing by adding computer controlled voltage sources to analog program the output current and voltage Additional inputs must be added to digitize the output current and voltage Setting and monitoring resolution is one to two orders of magnitude poorer than the standard MPS provides External setting and monitoring complicates cabling Degradation of the output current stability due to the addition of external cabling is undefined Output noise specifications are rarely given and sometimes vary with the type of magnet load driven These multiple unit configurations require up to 36 inches of rack space 1 5 Introduction Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 1 3 3 Highly Efficient Air Cooled Compact Unit Lake Shore MPS Quiet switched mode design The output uses
77. del 620 622 623 647 Magnet Power Supply User s Manual Table B 2 Additional MPS Mainframe Control Bus Remote Commands Input Command Query ADR Mainframe address Multidrop address 0 32 available Commands sent must have the address as the first character Query response will be OO thru 32 LOC CMD Mainframe Programming Status Query response will be the same LOCK as what is programmed There is no real change in Mainframe status MPS equivalent commands are UNLOCK LOC UNLOCK MODEO MODEO REM LOCK REM MODE2 MODE Mainframe Operational Status Query response is status byte register contents comma standard event status register contents ERRC equivalent to STB and ESR queries Form of the response is XXX XXX where XXX ranges from 000 to 255 SRE and ESE are forced to 255 to get a status response Mainframe Error Status Query response is equivalent to ERR a ea WA RA Output Current Setting MPS equivalent commands are WA ISET ISET RA PO O Output Current Polarity Setting and Status o o AD1 AD8 Output Current Measurement MPS equivalent command IOUT ae ae ee Output Voltage Measurement MPS equivalent command VOUT AD3 AD7 Internal Control Voltages Query response forced to 000 until required responses are defined Communications Baud Rate Not Supported Fixed at 9600 BaD fF Turn Mainframe Power ON Not Supported Ge Turn Mainframe Power OFF Not Supported Reset Mainframe
78. e DB 25 connector Used to connect Model 622 623 to Serial Port on rear of Customer s computer See Figure 5 5 RJ 11 to DE 9 Adapter Adapts RJ 11 receptacle to female DE 9 connector Used to connect Model 622 623 to Serial Port on rear of Customer s computer See Figure 5 6 6007 Serial Optical Isolation Link 8072 IEEE 488 Interface Cable Cable is 3 4 feet 1 meter in length MAN 623 Model 622 623 User s Manual MST 410 Transverse Probe Used in electromagnetic fields This probe is the same as used with the Lake Shore Model 410 Gaussmeter Axial Probe Used in electromagnetic fields This probe is the same as used with the Lake MSA 410 Shore Model 410 Gaussmeter MPEC 410 3 Extension Cable Used with the Model MST 410 and MSA 410 listed above Hall Sensor Magnetic Field Cryogenic Transverse This is an individual transverse Hall HGCT 3020 sensor meant for use in cryogenic magnet applications Refer to Paragraph 6 2 1 for mounting considerations Hall Sensor Magnetic Field Cryogenic Axial This is an individual axial Hall sensor HGCA 3020 meant for use in cryogenic magnet applications Refer to Paragraph 6 2 1 for mounting considerations MCT 3160 WN Probe Magnetic Field Cryogenic Transverse This is a complete 60 inch long Probe Assembly using a Model HGCT 3020 Transverse Hall Sensor Probe Magnetic Field Cryogenic Axial This is a complete 60 inch long Probe Assembly using a Model HGCA 3020 Axial Hall Sensor fF
79. e MPS still limits constant output current to 1 A not 10 A Changing ISET to 10 A allows a constant output current of 10 A and so on To set IMAX move to the IMAX SET line and enter the maximum current allowed for the magnet COMPLIANCE 0 00 V to 5 00 V 620 30 00 V 622 amp 623 or 32 00 V 647 Compliance Voltage Limit The MPS cannot exceed the Compliance Voltage Limit of the given model Set the compliance voltage lower than the rated voltage of both the magnet and if present the magnet protection diodes Determine these values from magnet manufacturer information Once the user enters a Compliance voltage the MPS retains it in non volatile memory as the default value Some magnets come equipped with diodes across the magnet leads to protect the magnet in the event of a magnet quench or a ramp rate that produces a charging voltage that exceeds the rated voltage of the magnet Set the MPS voltage limit to below the rated voltage of the protection diodes CAUTION Never set the MPS voltage limit above the rated voltage of the magnet s built in protection diodes Doing so may result in damage to the magnet and or its diodes If the magnet voltage reaches the MPS compliance voltage during charging the MPS limits the ramp rate and holds the voltage at the compliance until the end of charging or until the ramp rate falls below Si where Vset MPS compliance voltage and L magnet inductance in henrys The MPS automatically swit
80. e address as 12 and the terminators as CR LF 4 1 4 2 Run The Example QuickBasic Program Use the following procedure to run the QuickBasic Program 1 Copy c gpib pc Qbasic qbib obj to the QuickBasic directory QB4 2 Change to the QuickBasic directory and type link q qbib obj bqlb4x 1ib 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 1 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 See Table 4 1 Name the file ieeeexam bas and save 5 Run the program 23 Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 1 5 Notes On Using the IEEE Interface The term free field indicates a floating decimal point that may be placed any appropriate place in the string of digits term indicates where the user places terminating characters or where they appear on a returning character string from the MPS To chain commands together insert a semi colon comma or blank space between them Some programming languages allow only blank spaces to chain Multiple queries cannot be chained The MPS responds to the last query entered when addressed as a talker Queries generally use the same syntax as an associated settin
81. e interfaces 3 Through analog inputs and outputs 4 Through optional Lake Shore MPS Driver Software ONOONRWN gt Automatic Mode Easily controls Superconducting Magnets using the Model 6228 Persistent Switch Heater Option Card IEEE 488 Interface Option Model 6226 6476 Liquid Helium Level Gaussmeter Input Option Card Model 6228 Persistent Switch Heater Option Card Protection Overvoltage Quench protection circuits which limit or turn off the MPS output or turn off the input in the event of an abnormal condition current step limit exceeded internal overtemperature AC line loss detection remote inhibit output power exceeded Front panel annunciators an audio alarm and a contact closure indicate faults Introduction 1 1 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 1 2 SPECIFICATIONS Below are performance specifications for current with a 1 Henry load and voltage with a resistive load DC Output True Four Quadrant Bidirectional Power Flow output Autoranging current and voltage operate as a source or a sink in either polarity in current or voltage mode Program current and compliance voltage via the front panel remote interfaces or analog input See Table 1 1 for DC Output Specifications Model 620 Model 622 Model 623 Model 647 Current 0 to 50 A Current 0 to 125 A Current 0 to 155 A Current 0 to 72A Voltage 0 to 5 V Voltage 0 to 30 V Voltage 0 to 30 V Voltage 0 to 32 V Max Power
82. e same information that is sent e Add a query to the end of a command string if the controller must return information For example RMP 0 RMP commands the MPS to pause the ramp then return the ramp status to confirm the change e The MPS returns nothing queries without a and ignores misspelled commands and queries e The term free field indicates a floating decimal point that can be placed at any appropriate place in the string of digits e Leading zeros and zeros following a decimal point are unneeded in a command string but they are sent in response to a query A leading is not required but a leading is required e term indicates where the user places terminating characters or where they appear on a returning character string from the MPS Table 4 3 Sample BASIC Serial Interface Program SEREXAM BAS EXAMPLE PROGRAM FOR SERIAL INTERFACE This program works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible with a serial interface It uses the COM1 communication port at 9600 BAUD Enter an instrument command or query at the prompt The command transmits to the instrument which displays any query response Type EXIT to exit the program NOTE The INPUT instruction in this example accepts no commas as part of an input string If a comma appears in an instrument command replace it with a space CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may ne
83. ed more BAUDS 9600 TERMS CHRS 13 CHR 10 Terminators are lt CR gt lt LF gt OPEN COM1 BAUDS N 8 1 RS FOR RANDOM AS 1 LEN 256 INPUT ENTER COMMAND or EXIT CMDS Get command from keyboard CMD UCASES CMDS Change input to upper case IF CMDS 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 RS Mii If query read response N 0 Clr return string and count 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 D Add 1 to timeout if no chr RSS RSS INS Add next chr to string WEND Get chrs until terminators IF RSS lt gt THEN See if return string is empty RS MIDS RSS 1 INSTR RSS TERMS 1 Strip off terminators PRINT RESPONSE RSS Print response to query ELSE PRINT NO RESPONSE No response to query END IF END IF Get next command GOTO LOOP1 Remote Operation A8 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 SUMMARY OF IEEE 488 SERIAL INTERFACE COMMANDS Below is an alphabetical list of IEEE 488 Serial Interface commands consisting of Operational Commands Paragraph 4 3 1 Interface Commands Paragraph 4 3 2 Ramping Commands Paragraph 4 3 3 Current Zero Commands Paragraph 4 3 4 Current Step Limit Co
84. eeseeaeees 4 8 4 2 2 Serial Interface Settings sccur eiai N ANE ASE aA EEE Ea 4 8 4 2 3 Sample BASIC Serial Interface Program 4 8 4 2 4 Notes on Using the Serial Interface 4 9 4 3 Summary of IEEE 488 Serial Interface Commande nnn 4 10 4 3 1 Operational Commands Description 4 11 4 3 2 Interface Commands Description sssssssesnessestnntensstettt tnnt trsttttrnnnntettrtnnn nnanet tEnn Ennn ee nenn 4 13 4 3 3 Ramping Commands Description ccccceceeeeeceeceeeeeeeeecceeeeeeeesecseneceeeeeeesecsinaneeeees 4 14 4 3 4 Current Zero Commands Description 4 15 4 3 5 Current Step Limit Commands Description cecceceeceeeeeeeeeeeeeeeeeeeeeeeeenaeeeeeeeeseenaees 4 16 4 3 6 Computed Field Commands Description 4 17 4 3 7 Common Commands Description 4 18 ii Table of Contents Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 5 ERROR MESSAGES AND TROUBLESHOOTING ek 5 1 5 0 General icici iene A ae a en ee ee een ee el 5 1 5 1 Software Error Meesagesg ec cee ieieeetiaee iiieeeetea sled NENNEN nee avi NENNEN N 5 1 5 2 Factory Default Setting ve ee ELAegfn steen Eeuguetes N cae sthagete ladeceadlavincta ten lank etnanens 5 4 5 3 le te TEE 5 5 5 4 PertormancGe Testat camiadan ao aa Ed de dE 5 6 5 5 Rear Panel Connector Details cccccceccececceeceeeeeeeeecencaeceeeeeeeseceaeaeeeeeeeeesensaeaeeeeeeeseteenaees 5 8 5 6 IEE
85. en output current falls below 1 A the MPS turns OFF the front panel Fault annunciator and alarm and opens the FLT contacts When the MPS detects no OVP activity the Normal Display appears The MPS continues to display OVP and sounds the alarm until the user enters new output settings then turns them OFF This latching action informs the user of OVP activity The MPS opens the FLT contacts upon detecting OVP inactivity Level Alarm Reached A unique level probe zero reference feature allows the user to define the current liquid level reading as the zero reference and reads levels above or below that reference If turned ON the software level alarm notifies the user if the continuously variable liquid level reaches the set point The MPS closes the FLT contacts to indicate the fault sounds the alarm about once per second and displays The alarm sounds until the level alarm is turned OFF When it is turned OFF or disabled the MPS opens the FLT contacts and silences the alarm Low AC LO AC Detected If the AC line falls below 80 of the nominal line selected the MPS enters AC Loss Mode If this occurs on power up the MPS turns off the front panel circuit breaker and displays This indicates that the AC source does not match the line voltage listed on the rear panel Upon utility loss during normal operation of a single MPS with a charged load the MPS disables utility input circuitry and uses the load a
86. en the current reaches 100 5 amperes it dwells for 30 seconds at that current After the 30 seconds the current ramps at the MGT RATE to 100 1 0025 99 75 amperes that is half of the 0 5 in the opposite direction The 30 second dwell begins when the current reaches 99 75 amperes The process continues at 100 1 0 00125 100 125 amperes then 100 1 0 000625 99 9375 amperes then 100 1 0 0003125 100 031 amperes and finally 100 amperes To access the dithering feature turn ON up position switch 5 of the rear panel CAL AND ID DIP switches Select DELAY DITHER from Function Menu 3 to display the AUTOMATIC MODE DELAY screen shown to the right To enable dithering move the cursor to the last line using the Up Down cursor keys Press either the Data Entry up or down key to toggle the Dither Feature on and off Default is off For our example the DITHER delay changes to 30 S from the default 60 S The dither of 0 5 is the default If a Dither of 1 were entered the process would produce 1 over the MGT END then 0 5 under 0 25 over 0 125 under 0 0625 over and finally the MGT END selected The last line of the Automatic Mode screen shows the stage of the dithering The screen above indicates the first current of the dithering at 0 5 above the 100 amperes with 20 seconds left in the Dither delay Press either the Data Entry up or down key to skip the delay and ramp immediately to the next current in the di
87. ent unless area is well ventilated If inhaled remove to fresh air If not breathing give artificial respiration If breathing is difficult give oxygen Get medical attention e Liquid helium can cause severe frostbite to exposed body parts DO NOT touch frosted pipes or valves For frostbite consult a physician immediately If a physician is unavailable warm the affected parts with water that is near body temperature MAGNET QUENCHES For protection during a magnet quench fit the dewar with pressure relief valves of sufficient size and pressure rating to allow the helium gas to escape and to prevent excessive pressure in the dewar Operating a magnet in a dewar without proper pressure relief is dangerous and possibly life threatening The magnet may transfer tremendous energy to the cryogen during a quench Consult both the magnet and dewar manufacturers to check pressure relief valve sufficiency DANGEROUS VOLTAGES High voltages are present inside the MPS Never attempt to service the MPS Refer all service to qualified personnel There are no user serviceable parts inside the MPS The MPS current output terminals may be dangerous Although MPS output voltage is limited to 40 VDC a catastrophic failure inside the MPS could pass lethal voltages to the output terminals Do not touch the terminals during MPS operation vi Forward Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual BEFORE YOU OPERATE THE EQUIPMENT
88. envect censtineccentviesnunties annanru EEN EES ce EE SEENEN EES eee 1 1 1 0 General ae a en een ee 1 1 1 1 RE 1 1 1 2 SPECICATION EE 1 2 1 3 Operating Characteristics jo iccctecsccetedexeciacenetest ets ERARE EEN ENE AAE ARE EEEE E AEE EA REE 1 4 1 3 1 True Four Quadrant Bidirectional Power FIOW ccccssssssseeeceeeceseeseseeeeeeeeaeeaseeeeeeeeeeees 1 4 1 3 2 Low Noise High Stability Current Regulated Output 1 5 1 3 3 Highly Efficient Air Cooled Compact Un 1 5 2 INI IAL SETUP AND CONNECTIONS 0 0 ccceseeeecee cece eeeeeeeeeeee ener enaenaeeeeeeeeeesaaeaaeseaneeceeesesnasseaneeseeeensee 2 1 2 1 Inspecting ANd UNPACKING 0 ee eee ee ceeeeeeeeeeeeeeeeeeaeeeseeeaeeeceeaaeeeeeeaeeeeeeaeeeseeaeeeseenaeeeeseaes 2 1 2 2 MPS Mountng See concen rii eines niet iit niin enn ie ee nn 2 1 2 3 Environmental Requirements cesses sessaeaeeeeeeeeesessneaeeeeeeeeeenaees 2 1 2 4 Connecting the MPS to POWE ccc ccececenceecececeeceeneeceeeceneaeeeentetesecencnessensaaeeeceaeaeeeateceendeaeaeeees 2 1 2 4 1 Power and Ground Reouirements tens testrtrtnnttestttrntnnnresttnnn nannten tnnn nenene nt 2 2 2 4 2 MPS Input Power RatinNgS e sesasine iT aa iniaa aR A le eati aR E aaea ETa 2 2 2 4 3 Input Power Connections c ccccccceceeeeeeeeeaeee cece eeeneaeaeceeeeeseseceaeaeceeeeesaeeenaeeeeeeeeseenaees 2 2 2 5 POWCR UP cies enee e EE ches ie Ee EE 2 3 2 5 1 Magnet Cable Connections rociero tie iaa A EA A REAREA AT ERELT 2 3 2 5 2
89. er than the substrate and with a depth the same or slightly greater than the thickness of the package Tack the leads outside the slot with GE 7031 varnish or other similar substance Sparingly apply the mounting substance to the corners or a dot on each side of the sensor to hold it in place Avoid applying mounting substance on top of the sensor Alternately use Kapton tape or a mechanical cover over the top of the sensor to keep it in place The tape or cover should apply only light pressure to the sensor If epoxy is the mounting substance use it sparingly and use the same type as is used in the sensor Stycast 2850 FT epoxy Never pot the probe A room temperature calibration over the range of 30 kG comes with each probe The calibration specifies the terminating resistor not included required to maintain an accuracy of 1 of reading up to 30 kG and 2 of reading up to 150 kG over the entire temperature range For a terminating resistor use a metal film resistor with 1 or better accuracy mounted across the output voltage leads as close to the probe as is practical To extend the leads use AWG 34 stranded copper with Teflon insulation the same wire used on the probe Any impedance in the output leads acts as a voltage divider with the terminating resistor Probe reading reproducibility is within 1 over repeated thermal cycling between 4 2 K and room temperature 6 2 2 The Model MSA 410 and MST 410 Hall Sensors Models MSA 410 and M
90. es the status Use any numeric entry mode to change the value ZERO REF 0 0 Reading and lt OFF gt or lt ON gt Level Zero Reference Value and Status The Data Entry up or down arrow toggles the status When ON the value entered is the zero reference reading which the software subtracts from the actual level reading to give a relative level reading Use any numeric entry mode to change the value CALIBRATE SENSOR Change level sensor length units and calibration from this screen The Data Entry up or down arrow displays the Level Calibration screen If the level alarm is on and the MPS detects that the level alarm has been reached the MPS closes the FLT contacts to indicate the fault sounds an alarm about once per second and displays the screen to the right The alarm continues to sound until the level alarm is turned off When the alarm is turned off or disabled the MPS opens the FLT contacts and turns off the alarm CR Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 6 2 5 2 Field Probe Setting and Calibration Press Function Menu and then Next Menu to display Function Menu 2 Press the FIELD Function key to display the Field screen to the right FIELD PROBE SETTING UNITS T or kG Field Units The Data Entry up or down arrows scroll between the units T tesla or kG kilogauss The default is kG CALIBRATE PROBE NOTE The entries below change probe
91. esponds Only the addressed device responds to these commands The MPS 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 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 SRQ Status Register This status register contains important operational information from the unit requesting service The SPD command ends the polling sequence 4 1 2 2 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 See Paragraph 4 3 for a complete listing of all MPS common commands 4 1 2 3 Interface and Device Specific Commands Device Specific Commands are addressed commands The MPS supports a variety of Device Specific commands to program instruments remotely from a digital computer and to transfer measurements to the co
92. eturns 1 character plus up to 2 terminators Supported by Control Bus Programs MPS Interface Terminating Characters TERM type where type 0 for a carriage return and line feed CR LF amp 1 for a line feed and carriage return LF CR 2 for a line feed EPO 3 for no terminating characters DAB DAB Last Data Byte Terminating characters are sent when the MPS completes its message on output They also identify the end of an input message Control Bus fixes terminators at CR LF on receipt and transmission Terminator Query TERM 0 for a carriage return and line feed CR LF amp 1 for a line feed and carriage return LF CR 2 for a line feed LFE 3 for no terminating characters DAB DAB Last Data Byte Control Bus fixes terminators at CR LF on receipt and transmission Remote Operation da Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 3 Ramping Commands Description The following MPS Ramping Commands configure the various functions of the ramping features RAMP Programs Ramp Segment Parameters Input RAMP segment initial ramp current final ramp current ramp rate 00 where segment 1 Future updates will allow up to nine segments initial ramp current 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A 647 final ramp current 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A
93. for a sample BASIC program to establish communications between the computer and the MPS The Serial Interface shares Device Specific commands with the IEEE 488 interface listed in Paragraph 4 3 However without the advantage of the IEEE 488 Architecture there are several limitations e The OPC and RST Common Commands are not supported e The END Bus Control Command is not supported e Terminators are fixed to CRLF e A query must be added to the end of a command string if the MPS must return information Over IEEE 488 the last query response is sent when addressed to talk For example ISET 10 ISET would set the output current to 10 A and immediately query the output current setting LSCI Model 2002 RJ 11 to DB 25 SERIAL I O To customer supplied Adapter computer with DB 25 Serial Interface Connector configured as DCE If the interface is DTE a Null Modem Adapter is required to exchange Transmit and Receive lines Serial Interface Output on rear of MPS The Model 2001 2002 and 2003 are options available from Lake Shore Use whichever adapter that matches your computer serial interface connector Pin outs are described in Paragraph 5 7 LSCI Model 2003 RJ 11 Ba To customer supplied to DE 9 Adapter Il computer with DE 9 Serial Interface Connector configured as DTE If the interface is DCE a Null Modem Adapter is required to exchange Transmit and Receive lines
94. g command followed by a question mark They most often return the same information that is sent Some queries have no command form Leading zeros and zeros following a decimal point are unneeded in a command string but they are sent in response to a query A leading is not required but a leading is required As characters are received over the interface they store in a buffer with a length of 95 characters After receiving the terminators any new parameters are stored The Mainframe requires about 100 msec to store new parameters before receiving any new commands The Mainframe implements new parameters and updates measurement data once per 500 msec operation cycle noted by the blinking asterisk to the left of the mode status Sending new parameters or requesting data at a rate faster than 2 Hz is not recommended Table 4 1 Sample 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
95. g remote voltage sensing operation If the S lead opens the output voltage changes because it is sensed between OUT and the negative side of the load If the S lead opens the output voltage changes because it is sensed between the positive side of the load and OUT If both leads open the output voltage is sensed internally MPS Rear View The procedure below configures the MPS for remote voltage sensing as shown in Figure 2 3 Maintain 1 Turn off the unit Connect s to an 2 If present disconnect any wires between the OUT and OUT terminals SH and the S and S connections on the MPS rear panel 3 Connect the sense leads from the MPS S and S connections to the load Maintain polarity when making these connections CAUTION Maintain polarity between S and OUT and S and OUT The Figure 2 3 Remote S and S inputs control the output voltage Improper polarity may apply Sensing Connections damaging voltages to the load 4 Connect the ground shield to the mounting screw Make sure that the shield does not come into electrical contact with either magnet lead 2 6 MULTIPLE AUTO PARALLEL SETUP Connect up to four MPS units in an auto parallel configuration for increased output current capability The maximum total current allowed is the sum of the maximum currents of the individual units For example four 623 MPS units provide 4 x 155 620 amps total current The maximum total power is the sum of the maximum powe
96. gnal Ground SE Wu A 10 KQ potentiometer from ls to Is with center Si ignal tap to Ip produces the minimum voltage for full Ground Se scale current output 1 25 V for Model 622 or 1 55 V for Model 623 Voltage applied to Ip Transmit sums with internal current programming voltage Data S Remote voltage sense correction Correction for No No S load lead drops of up to 0 5 V per lead Connection Connection ana 5 8 Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 5 6 IEEE 488 INTERFACE CONNECTOR WHEN MODEL 6224 OPTION IS PRESENT Connect to rear MPS IEEE 488 Interface connector with cables specified in the IEEE 488 1978 standard document The cable has 24 conductors with an outer shield The connectors at each end are 24 way Amphenol 57 Series or equivalent with piggyback receptacles to daisy chain multiple devices Secure connectors in the receptacles by a pair of 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 total for a maximum of 15 devices The figure below and the table to the right shows the IEEE 488 Interface connector pin location and signal names SH1 AH1 T5 L4 SR1 RL1 PPO DC1 DTO CO E1 PIN SYMBOL DESCRIPTION 1 DIO1 Data Input Output Line 1 2 DIO2 Data Input Output Line 2 3 DIO3 Data Input Output Line 3 4 DIO4 Data Input Output Line
97. h Hall sensors requiring 100 mA of excitation current The Model 6476 Gaussmeter is designed to operate with high sensitivity Hall sensors requiring 1 mA or excitation current Cards identified by a 1996 copyright containing 6XX6 S firmware are field configurable to either model Options amp Accessories e Bi Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Below are specifications for the Model 6226 6476 Liquid Helium Level and Gaussmeter Input Card Liquid Helium Level Probe Type NbTi Superconducting Filament Sample Period Fixed at 5 seconds Number of Inputs 1 four lead measurement Maximum Resistance 428 Q Nominal Excitation Current 70 mA Display Resolution 1 0 1 inch 0 1 cm Compliance 30 V Electronic Accuracy 1 of full scale Input Voltage Resolution gt 1 mV out of 30 volts full scale Sample Interval 1 min to 24 hours continuous or read on demand Model 6226 Gaussmeter Cryogenic Hall Sensor Type Lake Shore Model HGCT 3020 transverse or Model HGCA 3020 axial Number of Inputs 1 four lead measurement Display Resolution 0 01 kG 0 001 tesla Nominal Excitation Current 100 mA Electronic Accuracy 1 of full scale Probe Magnetic Sensitivity 0 8 mV kG 30 Nominal Field Range Nominal 125 kG 0 8 mV kG Input Voltage Resolution gt 0 01 mV out of 0 1 volts full scale Sample Interval Probe excited continuously amp read when level is not Model 6476 Gaussmeter Cryogenic Hall Sensor
98. he order given Note any non compliance Test Setup 1 Connect input power to the MPS as outlined in Sections 2 5 through 2 5 3 of this manual 2 Disconnect any leads from MPS output terminals 3 Set Programming Mode Switches on the MPS rear panel s to the INT up position Set the CAL and ID switch 7 OFF down 4 Turn ON MPS Initially the display clears and the alarm sounds for a short time Within two seconds the Normal Display appears 5 6 Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Output Voltage Verification 5 From the MPS front panel select the Instrument Setup INSTR SETUP menu and change compliance voltage to 5 V Press the Normal Display key to return to the Normal Display screen Set output current to 1 A Use the DVM to read the voltage across the MPS unit s output terminals The reading should be 5 V 0 3 V Set output current to 1 A The DVM should read 5 V 0 3 V Turn OFF MPS Output Current Verification 9 10 11 12 13 14 15 16 17 Use AWG 4 wire to connect the current monitor shunt between the MPS OUT and OUT terminals Connect DVM across the shunt monitoring terminals Note DVM offset reading Turn ON MPS Within two seconds the Normal Display appears Select the Instrument Setup INSTR SETUP menu and change compliance voltage to 2 Volts Press the Normal Display key to return to the Normal Dis
99. he Operation Complete Bit in the Standard Event Status Register upon completion of all pending selected device operations This must be sent as the last command in a command string Returns one character plus up to two terminators Not supported by Control Bus Instrument Reset Command RST Nothing Restores MPS to power up settings just like the DCL and SDC bus commands The MPS reverts to the Normal Display Screen forces ramp status to the Hold mode and clears any latched error along with the Status Byte and the Standard Event Status Registers Not supported by Control Bus 4 19 SRE Input Remarks SRE Input Returned Remarks STB Input Returned Remarks TST Input Returned Remarks WAI Input Returned Remarks 4 20 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Enables Status Reports In The Service Request Enable Register SRE bit weighting where bit weighting the sum 000 to 255 of bit weighting of each bit to be set See the discussion on registers and below Each bit is assigned a bit weighting See the format of the Status Byte Register given below to see weighting and register placement of bits See the register section following the Common Command Table See Paragraph 4 1 3 1 for a complete description of status bits 7 6 5 43 241i o jet 128 64 32 16 8 4 2 1 Weighting SDR sRa EsB ovp ERR Rsc Lim ODR B
100. he current to 100 mA or greater while meeting all conditions 6 3 5 Model 6228 Remote Operation Commands IPSH Program PSH Current Input IPSH current where current a value from 0 to 125 mA Remarks The initial condition is 0 mA Current can be set from 0 to 125 mA but will actually be set in 4 mA increments IPSH PSH Current Query Input IPSH Returned A number between 0 and 125 Remarks Returns three characters plus up to two terminators PSH Program PSH Heater Status Input PSH status where status 0 to turn off the persistent switch heater or 1 to turn on the persistent switch heater Heater ON means persistence is OFF PSH PSH Heater Status Query Input PSH Returned 0 if the heater is OFF or 1 if the heater is ON If a current setting of 0 is entered the value returned is 0 Heater ON means persistence is OFF Remarks Returns one character plus up to two terminators PSHC PSH Compliance Status Query Input PSHC Returned 0 if PSH output is under the output compliance limit or 1 if the output is over the limit Remarks Returns one character plus up to two terminators PSHIS Current Setting When PSH Was Turned Off Input PSHIS Returned The value returned is a number between 125 0000 A Remarks Returns nine characters plus up to two terminators Options amp Accessories i ss i i lt CO BH Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual PSHS PSH Summary Query In
101. he definition B uo H M where to Uo 47 x 10 Him The lower one is not recognized under SI and is based on the definition B H J where the symbol is often used in place of J 1 gauss 10 gamma y Both oersted and gauss are expressed as cm g ss in terms of base units A m was often expressed as ampere turn per meter when used for magnetic field strength Magnetic moment per unit volume The designation emu is not a unit Recognized uder SI even thoug based on the definition B ul J See footnote c Ur W W 1 x all in SI p is equal to Gaussian p B H and uM H have SI units J m M H and B H 4r have Gaussian units erg cm R B Goldfarb and F R Fickett U S Department of Commerce National Bureau of Standards Bolder Colorado 80303 March 1985 NBS Special Publication 696 For sale by the Superintendent of Documents U S Government Printing Office Washington D C 20402 Magnetic Units A 1 A 2 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual This Page Intentionally Left Blank Magnetic Units Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual APPENDIX B MAINFRAME CONTROL BUS OPERATION B1 0 GENERAL There are seven elements to the Model 622 623 Mainframe Control Bus operating instructions Control Bus Serial Interface Specifications Paragraph B2 0 Control Bus Serial Interface Connector Paragraph B3 0 Control Bus Serial Interface Conf
102. he error is inactive or 1 if it is active Returns three characters plus up to two terminators Programs Upper Current Limit IMAX current where current a value between 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A 647 Programs the upper soft current limit of the MPS Truncates the value to the 0 001 place The initial condition is 000 0000 A The current limit is always forced to a plus Setting is limited by product limits Control Bus inputs 4 places display rounds to 0 01 or 0 001 place Current Limit Query IMAX A number between 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A 647 Nine characters plus up to two terminators are returned Value is shown as a but applies to both positive and negative entries Output Current Query IOUT or I A number between 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A 647 Returns nine characters plus up to two terminators Enter Output Current ISET current or current where current a value between 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A 647 Value is truncated to the 0 001 place Initial condition is 000 0000 A Setting is limited by IMAX Control Bus inputs 4 places display rounds to 0 01 or 0 001 place Output Current Setting Query ISET A number between 0 and 50 A 620 0 and 125 A 622 0 and 155 A 623 or 0 and 72 A
103. ight press the Function Menu key to display Menu 1 then the Next Menu key The 2 3 in the upper right corner indicates Menu 2 of 3 Without a PSH Option Card a 2 2 appears in the upper right corner indicating menu 2 of 2 With all options installed Function Menu 2 has four possible selections OUTPUTS ONLY LHe LEVEL FIELD and PSH SETUP lt NP gt indicates the function is Not Present and the associated function key is ignored Operation 3 7 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 6 2 1 Outputs Only Screen Press the OUTPUT ONLY Function key to display a Outputs Only Screen without LHe Level Field Option screen with output values in larger characters for fe ee eee Hl remote viewing There are two screens one with the ee LHe Level Field Option one without the LHe Level Field Option 3 6 2 2 LHe Level A Enters the Liquid Helium LHe Level screen See Paragraph 6 2 for a detailed description 3 6 2 3 Field Enters the Field screen See Paragraph 6 2 for a detailed description 3 6 2 4 PSH Setup Enters the Persistent Switch Heater PSH screen See Paragraph 6 3 for a detailed description 3 6 3 FUNCTION MENU 3 SCREEN PSH Option Card ONLY To display Function Menu 3 shown on the right press the Function Menu key then press the Next Menu key twice Function Menu 3 has one selection DELAYS NOTE The Delay Screen functions only with the PSH
104. iguration Paragraph B4 0 Selecting the Control Bus Serial Interface Address Paragraph B5 0 Control Bus Serial Interface Operation Paragraph B6 0 and a sample control bus serial interface program Paragraph B7 0 B2 0 CONTROL BUS SERIAL INTERFACE SPECIFICATIONS Serial Interface Configured Configured The MPS Mainframe control bus serial Specification For RS 232C For RS 485 De oe tes nee eae unbalanced single ended non Address Configuration Polled 1 32 terminated line for short distances 50 Feet 4000 Feet typically less than 50 feet where the Dual RJ 11 Modular phone Jacks host computer serial interface is dedicated to one MPS Mainframe RS 485 is a balanced terminated line for multidrop party line PT Ee and receivers sharing the same line 7 for data transmission Each interface ParityTye od O instrument has a unique address and operates in a polled mode Set the LF OAH MPS Mainframe to respond to one of 32 addresses B3 0 CONTROL BUS SERIAL INTERFACE CONNECTOR The serial interface connectors use dual standard 6 wire RJ 11 modular phone jacks The two Pin BSI Function RS 485 Function connectors are in parallel and facilitate the RS 485 1 No Connection No Connection multidrop configuration Lake Shore Model 2001 data cables which maintain pin 1 polarity simplify multiple Mainframe interconnection Lake Shore offers the Model 2002 RJ 11 to DB 25 adapter and Model 2003 RJ 11 to DE 9 adapter to
105. in the activate RI by shorting RI to RI with a relay contact closure event of catastrophic failure or a switch The Fault Indicator relay contact 3 FLT Fault Indicator A rel ere fie aed is open when the MPS detects ault Indica OI re ay con act Na closes to indicate a 4 FLT _ fault Contact rating 0 25 A resistive at 100 VDC 3 W 25 no faults When the MPS VA detects SE fault a 5 ON ON Indicator A relay contact that closes to indicate when remote int ibit or an output 6 ON the front panel circuit breaker is in the ON position Contact inhibit it lights the front panel rating 0 25 A resistive at 100 VDC 3 W 25 VA Fault LED and closes the relay contact The contact closure NONE Factory Use Only Do not connect to this terminal alerts other system components In auto parallel MPS configurations OVP ensures that the of the fault In an auto parallel activation of one MPS Over Voltage Protection circuit system up to four MPS units activates all the other parallel MPS units protection circuits connected in parallel these signals connect in parallel l MODE RI FLT between each of the MPS units SCH OVP Im Vm See Paragraph 2 6 for details CAL AND ID 12 3 4 5 6 7 8 9 10 on connections between two aco TI A ee connections to a rear panel ee mm Pm ee detachable terminal block See Table 5 1B for ae in Table 2 2 and Figure DIP Switch Definitions pe Figure 2 1 Rl FLT ON and
106. ing asterisk indicating each update when the unit is in normal operation 2 5 1 Magnet Cable Connections WARNING Turn off the AC power before changing any rear panel connections and verify that all connections are securely tightened before reapplying power CAUTION Initially setup the MPS without connecting it to the magnet This lessens the chance for inadvertent damage to the load while the user learns MPS operation Make MPS load connections at the Table 2 1 Load Wire Lengths and Current Capacity OUT and OUT terminals on the rear panel These plated copper bus bars Ra Capacity Resistivity Total Lead Length feet accommodate 1 4 inch mounting AWG mm Amperes 0 1000 feet 75A 100A hardware Use load wires heavy enough BEE to limit the voltage drop to less than 0 5 0 0 09827 volts per lead This ensures proper 0 1563 regulation and prevents overheating S 0 2485 while carrying the output current Use 0 3951 remote sensing to compensate for any S 0 6282 voltage drop in the load leads and obtain a more accurate voltage reading Stranded AWG 4 wire is capable of carrying in excess of 125 amperes Keep conductor temperature under 85 C for a 35 C ambient Table 2 1 lists the ampere capacity and total OUT and OUT lead lengths for load connections If connecting multiple loads to the unit use separate pairs of wires to connect each load to the output terminals Cut each pair of connecting wires as short as possi
107. ing excursions from the desired Magnet End Current Default 60 seconds DITHER X XX The maximum dither excursion from the Magnet End Current in percent Default 0 5 DITHER lt OFF gt To enable dithering this must read lt ON gt Move the cursor to the last line using the Up Down cursor keys Press either the Data Entry up or down key to toggle the Dither Feature on and off Default is off 3 7 MANUAL PERSISTENCE CONTROL EXAMPLE Assume the magnet is in persistence with a current of 20 amperes It is desired to change the magnet current to 30 amperes and return to persistence mode Connect the MPS to the magnet and the PSH heater terminals to the persistence switch Turn on the MPS and set the PSH heater current to the desired current See Paragraph 6 3 2 to set heater current The Normal manual screen displays see Paragraph 3 3 First ramp the MPS to the value of current in the magnet Actually MPS current flows in the persistence switch not the magnet As MPS current increases the persistence switch current decreases eventually to zero Select a suitable ramp rate for current in the persistence switch enable the ramp if not enabled and enter 20 amperes into the setpoint setting The MPS ramps to 20 amperes After settling the MPS current equals the magnet current with zero current in the persistence switch Using the cursor keys move to the last line PERSISTENCE lt ON gt and press a Data Entry up or down arrow
108. is the default startup Normal Display screen for an MPS with a PSH option card installed and Automatic Persistence Control selected To change to Manual Persistence Control Mode press the MENU key and select MANUAL MODE For Manual PSH Control Mode see Paragraph 3 4 When using a Persistence Switch Automatic Mode simplifies superconducting magnet control After the user defines initial parameters Automatic Mode permits the MPS to use two different ramp rates and four time delays and to manage the Persistence Switch Heater to change magnet current from its existing value to a new value automatically Dithering is supported see Paragraph 3 9 Use the Cursor keys to move the line indicator up or down Change parameters using any numeric entry mode including the cursor MGT START 0 to 50 000 A 620 0 to 125 000 A 622 0 to 155 000 A 623 0 to 72 000 A 647 Magnet Start Current The current in the magnet in persistence prior to the automatic run The MPS opens the persistence switch after it reaches this current and the user specified delay expires Operation 3 3 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual MGT END 0 to 50 000 A 620 0 to 125 000 A 622 0 to 155 000 A 623 0 to 72 000 A 647 Magnet End Current The desired magnet current To set a new current move to the MGT END line and enter a new current then move to the RUN line and toggle to activate Automatic Mode The MPS automatica
109. is turned on To change channels access the PSH SETUP screen move the cursor to the CHANNEL line and use the Data Entry up and down arrows to increment to the desired channel Select Channel 0 to force the heater off If the heater is on and connected to a channel changing channels may cause problems A warning displays to prevent a mishap The Normal Manual screen shows which channel connects to the heater when the heater turns on persistence off When a zero displays the heater is off and not connected to any of the multiplexed outputs When a 1 through 8 displays then that multiplexed channel is controlled The magnet is put in and taken out of persistence via the last line on the Normal Manual Screen as with the 6228 PSH card To change the channel number access the Normal Manual Screen use the Right Left Cursor to move to the channel number and then use the numerical keypad entry keys The data Entry up or down arrow toggles the persistence on and off The Automatic Mode shown to the right allows channel selection on line 7 prior to running the Automatic change of persistence current To change the channel number on the Automatic Screen use the Right Left Cursor to move to the channel number and then use the numerical keypad entry keys The Data Entry up or down arrow does not toggle persistence on and off Persistence toggles on and off automatically 6 3 4 PSH Card Voltage Constraints The PSH Per
110. it Name Example If a bit in the Service Request Enable Register is set 1 its function is enabled and reported in the Status Byte Register For example to enable bits 1 2 4 and 6 send the command SRE86 86 is the sum of the bit weighting for each bit Bit Weighting 1 2 2 4 4 16 6 64 86 Service Request Enable Query SRE An integer from 000 255 Reads the Service Request Enable Register The integer returned represents the sum of the bit weighting of each bit set Returns three digits plus up to two terminators Status Byte Query STB An integer from 000 255 Reads the Status Byte Register The integer returned represents the sum of the bit weighting of each bit set Although this query acts like a serial poll it does not reset the register to all zeros Returns three digits plus up to two terminators Self Test Query TST 0 No errors 3 Reserved 6 AC High 9 Ol Active 1 Remote Inhibit Active 4 STP Error 7 Rail High 2 OVP Active 5 AC Low 8 Overtemperature Error A Setpoint Entry STP B Rate Entry STP C OPP Overpower Protection Error Causes instrument to report any failures Returns 1 character plus up to 2 terminators Wait to Continue Command WAI Nothing The command prevents the instrument from executing any further commands or queries until all previous ones have been serviced This command is accepted but not supported not the IEEE 488 2 defined operation Not supported by the Co
111. kmanship for a period of twelve 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 All products are thoroughly tested and calibrated to published specifications prior to shipment Calibration Certifications are offered for six month periods only Where such documentation must be updated 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 operation outside of the environmental specifications or from buyer supplied software interfacing It does not apply to damage caused by accident misuse 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
112. lays Screen RUN UP 60 S Run Up PSH OFF 60 S PSH Off RAMP END 60 S Ramp End PSH ON 60 S PSH On Manual Mode Screen CURRENT 0 000A Current Setting COMPLIANCE 1 000V Compliance Voltage Setting Cannot be changed in this screen RAMP RATE 1 000A S Ramp Rate RAMP ENABLE lt OFF gt Ramp Enable Off PERSISTENCE lt ON gt Persistence Status Not present if PSH option not installed Instrument Setup Screen FLD ENABLE lt OFF gt Magnetic Field Enable Off B UNITS kG Magnetic B Field Units kG A 0 100 Field per Amperes IMAX SET 50 000A 620 125 000A 622 155 000A 623 72 000A 647 Maximum Current COMPLIANCE 5 000V 620 30 000V 622 623 32 000V 647 Maximum Compliance Voltage Retains Last Setting On Power Down Step Limit Zero Screen CURRENT STEP LIMIT STATUS lt ON gt Output Current Step Limit Status STEP 10 000A Output Current Step Limit ZERO STATUS lt OFF gt Output Current Zero Status ZERO 0 000A Output Current Zero Value MODE INTERNAL Output Current Programming Mode Display Only Interface Setup Screen If Present IEEE ADD 12 IEEE 488 Address TRMS EOI CRLF EOI Terminators Carriage Return amp Line Feed and EOI On RS 232C 1200 N 8 1 Serial UO Definition 9600 Baud No Parity 8 data bits 1 stop bit CB DEF 9600 0 7 1 Control Bus Definition 9600 Baud Odd Parity 7 data bits
113. le cccceceeeeeeeececeeeeeeeseceeaeeeeeeeeeeeneueeeeeeeeeeesaees 3 9 3 9 Dithering in Automatic Mode 3 11 d REMOTE OPERATION Steeg deed deed EEGENEN 4 1 4 0 Ebert ee S ien Raed E ete dae ev Lge 4 1 4 1 IEEE 468 interfaco di a e eie ENEE eg eee dae uesieeedeceeaees eines 4 1 4 1 1 IEEE 488 Interface Settings 2 2 cece ccecececcceeceeecneneeceenenneceenneeseedseaeceenneeesedeaneseseaneeeensnes 4 1 4 1 2 IEEE 488 Command Structure cccccccececeeeeeceecaeeeeeeeeeeecacaeceeeeeseseccacaeeeeeeeseeecsiaeeeeeess 4 2 4 1 2 1 Bus Control Command Ssss hess aaaea ae a Eaa ENNEN daa deeeed 4 2 4 1 2 2 Common Command iececvieectevs ees eeevdiaelan ten Move aa aaaea a a a a aaaea aana ae aada Ea Teraa ai aada 4 2 4 1 2 3 Interface and Device Specific Commandes 4 2 4 1 3 Ee EE 4 2 4 1 3 1 Status Byte and Service Request Enable Registers 0 ccceeeeseeeeeeeseeeeeeeeeeeeeesieeeeeeaas 4 3 4 1 3 2 Standard Event and Standard Event Status Registers A 4 3 4 1 4 Example IEEE Setup and Program 4 4 4 1 4 1 GPIB Board Installaatio eniin ieira aa aaua ina aaea anaa aada 4 4 4 1 4 2 Run the Example QuickBasic Program ccceceeeeeeceeeeeeeceeeeceneeeeeeaeeeeeecaeeeseenaeeeeneaas 4 4 4 1 5 Notes On Using the IEEE Interface AA 4 5 4 2 Serial I O Interface dees ceedeveriad bee aaae a NEEN EEN NENNEN ENEE iaaa ia Ee 4 7 4 2 1 Serial Interface Hardware Configuration ccccccccecceceeeeeeeeeeeeeeeeeceeeeeeeseeeeeeesenae
114. 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 or to a recognized natural standard TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations as trademarks to distinguish their products Where those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and a proceeding or symbol CalCurve Carbon Glass Cernox Duo Twist Gamma Probe Quad Lead and Quad Twist are trademarks of Lake Shore Cryotronics Inc Kapton is a trademark of 3M Stycast is a trademark of Emerson amp Cuming Teflon is a trademark of DuPont De Nemours QuickBasic is a trademark of Microsoft Corporation Copyright 1995 1999 by Lake Shore Cryotronics Inc
115. lity restoration 1 4 True Four Quadrant Bi directional Power Flow V Output Voltage Energy flows from magnet to AC line Energy flows from AC line to magnet Output Current Energy flows from AC line to magnet Energy flows from magnet to AC line Ouput Current Output Voltage Figure 1 1 Four Quadrant Power Introduction Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Conventional MPS Consists of a unipolar power supply with an energy absorber to dissipate magnet energy during discharge The energy absorber prevents reverse voltage generated during the discharge from damaging the unipolar supply output Other conventional supplies dissipate magnet energy in the power supply output transistor pass bank This two quadrant performance requires the output stage to absorb considerable power during the discharge In addition uniform charge and discharge rates are not always ensured Current reversal requires external current reversal switches or manual lead reversal These units provide pseudo four quadrant operation which introduces discontinuities at the current reversal point produced by switching the leads Current reversal switches may incorporate direction detection diodes which reduce available magnet charging voltage and dissipate additional power Current reversal switches must also interlock to prevent lead reversal when current is present Current reversal swit
116. lly ramps to the new current returns the magnet to persistence then ramps MPS current back down to zero MGT RATE 0 to 99 999 A sec Magnet Ramp Rate Rate in amperes per second that the MPS charges the magnet Exceeding the maximum rated voltage or current ramp rate may damage the magnet The user may configure the MPS to limit the charging voltage The magnet manufacturer supplies the inductance of the magnet maximum ramp voltage and maximum current ramp rate The relationship for these parameters is given by the equation L a lt a dt where L magnet inductance in henrys di dt maximum magnet current ramp rate in amps second Vmax rated maximum magnet ramp voltage in volts To set the Magnet Ramp Rate for automatic PSH control move to the MGT RATE line and enter a ramp rate less than the magnet s maximum ramp rate Upon entering a new current set point the magnet current ramps at the entered magnet ramp rate PERS RATE 0 to 99 999 A sec Persistence Switch Ramp Rate Rate in amperes per second of the MPS when in Persistence Mode The current is flowing in the Persistent Switch and the rate is chosen as such To set the Persistence Switch Ramp Rate move to the PERS RATE line and enter a persistence switch ramp rate less than the maximum allowed This value is usually considerably higher than the magnet ramp rate as there is little inductance in the persistence switch LAST END The ending charge current from the last time
117. ls 620 622 623 are factory set for operation from 100 120 200 208 220 or 240 VAC 10 5 50 to 60 Hz single phase Model 647 is factory set for operation from 200 208 220 or 240 VAC 10 5 50 to 60 Hz single phase Input Protection A front panel 20 A two pole circuit breaker protects the AC input The MPS turns off the breaker in the event of a fault Remote Interfaces Serial Interface is standard IEEE 488 is optional All front panel functions can be controlled over the interfaces In addition interfaces output displayed quantities Input Current Table 1 1 Model 620 622 623 Input Current Table 1 2 Model 647 Input Current Nominal Line Line Voltage Maximum Input Nominal Line Line Voltage Maximum Input Voltage VAC Range VAC Current A rms Voltage VAC Range VAC Current A rms 1 2 Introduction Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Front Panel Contains a menu driven keyboard and graphic display for entry and display of results Operating parameters to set and monitor from the front panel and remote interface include e Output current and compliance voltage setting e Output current and voltage measurement e Status reporting e Output ramp programming Persistent switch heater control with optional Model 6228 Card Liquid helium level monitoring with optional Model 6226 6476 Card e Field Monitoring with optional Model 6226 Card e Output Current Zeroing
118. mmands Paragraph 4 3 5 Computed Field Commands Paragraph 4 3 6 and Common Commands Paragraph 4 3 7 OPERATIONAL COMMANDS CURRENT STEP LIMIT COMMANDS Cmd Function Cmd Function ERR Error Status Summary ISTP Output Current Step Limit IMAX Upper Current Limit ISTP Output Current Step Limit Query IMAX Upper Current Limit Query ISTPS Output Current Step Limit Status IOUT Output Current Query ISTPS Output Step Limit Status Query ISET Output Current Setting STEP Output Step Limit Exceeded Query ISET Output Current Setting Query STEPR1 Output Step Limit Exceeded Reset IV Output Summary Query OVP Overvoltage Protection Query COMPUTED FIELD COMMANDS RES Resolution Cmd Function RI Remote Inhibit Status Query CFPA Program Computed Field Amp Constant VOUT Output Voltage Query CFPA Computed Field Amp Constant Query VSET Compliance Voltage Setting CFUNI Program Computed Field Display Units VSET Compliance Voltage Setting Query CFUNI Computed Field Display Units Query CFPS Set Computed Field Display Status INTERFACE COMMANDS CFPS Computed Field Status Query Cmd Function END EOI Status Se E COMMON COMMANDS MODE Interface Status Mode CLS Interface Clear See ee SE Std Event Status Enable Reg TERM Tatminator Query ESE Std Event Status Query ESR Std Event Status Enable Query IDN Identification Query RAMPING COMMANDS OPC Operation Complete Cmd Function OPC Operation Complete Query RAMP Ramp Segment Parameters RST Reset C
119. mputer Most Device Specific Commands perform functions also performed from the front panel This section discusses Common and Device Specific commands Device Specific Commands consist of Interface Display Channel Control Process and Curve commands See Paragraph 4 3 for a complete listing of all MPS interface and device specific commands 4 1 3 Status Registers There are two status registers the Status Byte Register Paragraph 4 1 3 1 and the Standard Event Status Register Paragraph 4 1 3 2 aU Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 1 3 1 Status Byte and Service Request Enable Registers The Status Byte Register consists of a single data byte containing seven bits of MPS status information STATUS BYTE REGISTER FORMAT If the Service Request is enabled any bits that are set cause the MPS to pull the SRQ management low to signal the BUS CONTROLLER These bits reset to zero upon a serial poll of the Status Byte Register The Service Request Enable Register inhibits or enables any of the status reports in the Status Byte Register The SRE command sets the bits A bit that is set enables its function Inhibit these reports by turning OFF their corresponding bits in the Service Request Enable Register Refer to the SRE discussion Setting Data Ready SDR Bit 7 When set the MPS resets current and voltage to 0 A and 1 V because of OVP or RI activity Service Request SRQ Bit
120. nected in parallel A slave MPS with a display in a multiple MPS configuration displays S for slave instead of a number Polling at power up determines the number of units in parallel Operation 3 5 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 6 1 3 Step Limit Zero Screen Press the Function Menu key to display Function Menu 1 Press the STEP LIMIT ZERO Function Key to display the Step Limit Zero screen to the right This screen combines two features Current Step Limit and Current Zero Use the Cursor keys to move the line indicator up or Entry up or down key Change all others using any numeric entry mode including the cursor 3 6 1 3 1 Current Step Limit When a superconducting magnet quenches the magnet becomes resistive The output current forces the MPS output to the compliance voltage setting and the output current drops rapidly To avoid excessive cryogen boil off the output current setting should be changed to 0 as quickly as possible The output current step limit if exceeded automatically resets the output to 0 A The Step Limit function also prevents the user from entering steps that exceed the current step limit STATUS lt OFF gt or lt ON gt ISTEP 0 010 Ato 999 99 A Output Current Step Limit Status Output Current Step Limit 3 6 1 3 2 Current Zero There may be configurations like multiple auto parallel MPS units that introduce an output current offset from zero This
121. nt output cables 3 Repack the MPS upside down in the original box If returning the MPS to Lake Shore and original box is unavailable please call Lake Shore for a replacement box 4 Label the box for storage or shipment 2 9 RETURNING EQUIPMENT TO LAKE SHORE To return the MPS for repair or replacement obtain a Return Goods Authorization RGA number from a factory representative before returning the instrument to our service department When returning an instrument for service Lake Shore requires the following information before attempting any repair 1 Instrument model and serial number User s name company address and phone number Malfunction symptoms Description of system Returned Goods Authorization number aR WN Consult the factory for shipping instructions Ship the MPS upside down in the original shipping box Setup amp Connections e Z Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual This Page Intentionally Left Blank Setup amp Connections Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTER 3 OPERATION 3 0 GENERAL This chapter covers seven areas MPS Front Panel Paragraph 3 1 Power Up Paragraph 3 2 Setting Current on an MPS with Manual PSH Control Paragraph 3 3 Setting Current with Automatic PSH Control Paragraph 3 4 Instrument Setup Screens Paragraph 3 5 Function Menus Paragraph 3 6 and an Automatic Persistence Control Example Par
122. nter Multiple MPS Remote Inhibit Mode They activate their output over voltage protection OVP circuits and turn off their output circuits If a charged load is present the OVP circuits discharge it the front panel Fault annunciators turn ON and the alarm sounds about once per second If a MPS detects a fault it closes the FLT contacts to initiate Multiple MPS Remote Inhibit Mode 5 1 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual No delay is allowed CAL AND ID switch 7 OFF down and multiple MPS operation CAL AND ID switch 4 ON up must be selected After the load discharges turn OFF all units to reset The MPS displays the OVP error message Overvoltage Protection OVP Circuit Activated If the voltage across the MPS output terminals rises above 40 volts the output over voltage protection OVP circuit activates The MPS also may activate the OVP circuit in response to faults Upon activation the OVP circuit uses thyristors to crowbar the output voltage to between 1 and 1 3 volts until magnet current reaches zero If this occurs change the output current setting to zero If the MPS detects OVP activity on power up output current greater than 1 A it turns ON the front panel Fault annunciator closes FLT contacts and sounds the alarm twice per second When the MPS detects the fault it closes the FLT contacts to indicate a fault sounds the alarm once per second and displays Wh
123. ntials 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 Forward v Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Identification of Electrostatic Discharge Sensitive Components Below are various industry symbols used to label components as ESDS H A E2 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
124. ntrol Bus Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTER 5 ERROR MESSAGES AND TROUBLESHOOTING 5 0 GENERAL This chapter covers Software Error Messages Paragraph 5 1 Factory Default Settings Para graph 5 2 Calibration Procedure Paragraph 5 3 Performance Test Paragraph 5 4 Rear Panel Connectors Definition Paragraph 5 5 IEEE 488 Connector Definition Paragraph 5 6 and Serial Interface Cable and Adapters Paragraph 5 7 5 1 SOFTWARE ERROR MESSAGES The MPS constantly monitors its circuits for faults like low or high line voltage line loss or internal temperature and rail faults Upon detection the error and a brief description display Below are error messages that may display during normal operation Error 01 Unwriteable NOVRAM Error Error 06 Calibration Data NOVRAM Error Output Current Step Limit Exceeded If the MPS detects an output current change that exceeds the step limit it enters Step Limit Mode and forces MPS output to 0 amps and 1 volt On the next display update cycle the MPS closes the FLT contacts to indicate the fault sounds an alarm about once per second and displays QUTPUTS Error Messages amp Troubleshooting The MPS sounds the alarm and halts operation until the user presses a Data Entry up or down key to clear the fault When the fault clears the MPS opens the FLT contacts silences the alarm and dis
125. nts new parameters and updates measurement data once per 500 millisecond operation cycle Do not send new parameters or request data at a rate faster than 2 Hz Mainframe Control Bus Operation BA Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual B7 0 CONTROL BUS SERIAL INTERFACE SAMPLE PROGRAM The following PC program is an interactive program that prompts the user for a Mainframe command and displays the Mainframe response The command must include a query for the Mainframe to respond This QuickBasic 4 0 program is for an IBM PC or compatible Enter the Mainframe command at the prompt The Mainframe response then displays END exits the program COUNT 1000 TERMS CHRS 13 CHR 10 OPEN com1 9600 0 7 1 RS FOR RANDOM AS 1 LEN 256 INPUT ENTER COMMAND END TO EXIT CMDS CMDS UCASES CMDS IF CMDS END THEN CLOSE 1 END PRINT 1 CMDS TERMS IF INSTR CMDS W lt gt 0 OR INSTR CMD XD lt gt 0 OR INSTR CMDS lt gt 0 THEN RSS oun N 0 WHILE N lt COUNT AND R INPUTS LOC 1 IF R THEN N RSS RSS R WEND IF RSS lt gt THEN RSS MIDS RSS 1 INSTR RS TERMS PRINT RESPONSE RS ELSE PRINT NO RESPONSE END IF END IF GOTO L1 INSTR RS TERMS 0 OR RSS 1 N 1 ELSE N 0 END Ba Mainframe Control Bus Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Table B 1 MPS Mainframe Cont
126. nual 4 1 2 IEEE 488 Command Structure The Model 622 623 supports several command types There are three groups of commands 1 Bus Control see Paragraph 4 1 2 1 a Universal 1 Uniline 2 Multiline b Addressed Bus Control 2 Common see Paragraph 4 1 2 2 3 Interface and Device Specific see Paragraph 4 1 2 3 4 1 2 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 The MPS recognizes two of these messages from the BUS CONTROLLER Remote REN and Interface Clear IFC The MPS sends one Uniline Command Service Request SRQ REN Remote Puts the MPS into remote mode IFC Interface Clear Stops current operation on the bus SRQ Service Request Tells the bus controller that the MPS 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 There are two Multiline commands recognized by the MPS LLO Local Lockout Prevents the use of instrument front panel controls DCL Device Clear Clears MPS interface activity and puts it into a bus idle state Finally Addressed Bus Control Commands are Multiline commands that must include the MPS listen address before the instrument r
127. o O Output Cable Set Output cables are 4 AWG Each cable is 12 feet 3 meters long MCA 2560 WN 614 Options amp Accessories Volume magnetization Volume magnetization 10 4n Magnetic polarization An x 107 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual APPENDIX A UNITS FOR MAGNETIC PROPERTIES Conversion from CGS to SI Units Quantit Gaussian Conversion SI amp 3 amp CGS emu Factor C Rationalized mks tesla T Wb m weber Wb volt second Ves ampere A 107 10 8 10 3 2i intensity of T Wb m magnetization Aem ko o M Magnetic dipole moment 3 3 6 3 Magnetic moment m X Permeability Relative permeability Volume energy i Ww density energy product Demagnetization factor Aen joule per tesla J T Wbem 1 10 4n x 10 dimensionless e p Henry per meter emu cm 4r x 10 H m Wb Asm Him Wb Aem 4m x 10 not defined i dimensionless erg cm 10 Jim Ui dimensionless NOTES a b c j k Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 47M Multiply a number in Gaussian units by C to convert it to SI e g 1 G x 10 T G 10 T SI Syst me International d Unit s has been adopted by the National Bureau of Standards Where two conversion factors are given the upper one is recognized under or consistent with SI and is based on t
128. o the GND terminal white or blue to the N terminal and black or brown to the L terminal 4 Position the strain relief close the cover and then tighten the cover screws 5 Connect the other end of the power cord to an appropriate AC power source 6 Plug the power cord into the detachable power connector plug on the MPS rear panel 2 5 POWER UP Read and follow instructions in Paragraphs 2 1 thru 2 4 3 and safety recommendations in the Foreword before applying power to the MPS Do not connect the MPS to the magnet at this point Short the output terminals together with a 4 gauge or larger cable This protects the magnet against incorrect configurations Turn on the MPS It requires approximately 2 seconds for initialization Initially all front panel annunciators come on and the alarm sounds for a short time Within 1 second the Fault and Persistent Switch Heater On annunciators and the alarm turn off If the MPS detects a high or low AC line fault it blinks the front panel Fault annunciator and turns off the input circuit breaker If this occurs verify that the AC source matches the line voltage listed on the MPS rear panel The MPS front panel AC On LED lights any time the MPS is connected to the AC line and the MPS power switch is ON Initially the entire display clears and the alarm sounds for a short time The MPS initializes itself and displays the model identification The Normal Display screen appears with a blink
129. omagnetic phenomena which either directly or indirectly may degrade electronic system performance Natural EMI includes thunderstorms solar disturbances cosmic rays etc Man made EMI includes fixed and mobile transmitters high voltage power lines power tools and appliances florescent lights and other equipment containing motors heaters etc Protect the AC source from EMI Consider transient surge protectors for lightning protection 2 4 2 MPS Input Power Ratings Operate the Model 620 622 623 from a nominal 100 120 200 208 220 or 240 VAC 10 5 single phase AC power source 50 to 60 Hz Table 1 1 lists input voltage range and maximum current required for each nominal input Operate the Model 647 from a nominal 200 208 220 or 240 VAC 10 5 single phase AC power source 50 to 60 Hz Table 1 2 lists input voltage range and maximum current required for each nominal input A rear panel label indicates MPS factory preset nominal line voltage Normally the line voltage setting is not changed in the field Consult the factory to reconfigure the input power 2 4 3 Input Power Connections The MPS uses a three prong detachable input power connector supplied to mate with the UL CSA IEC approved rear panel AC input connector The user supplies a three conductor power cord rated for at least 85 C operation For 100 or 120 VAC operation each conductor must be AWG 14 or larger For 200 208 220 or 240 VAC operation each conduc
130. ommand RAMP Ramp Segment Parameters Query SRE Service Request RME Ramp Status SRE Service Request Query RMP Ramp Status Query STB Status Byte Query SEG Active Ramp Segment TST Self Test Query SEG Active Ramp Segment Query WAL Wait To Continue CURRENT ZERO COMMANDS Cmd Function IMODE Current Programming Mode Query VMODE Voltage Programming Mode Query Zl Zero Current Value Status ZI Zero Current Value Query ZIS Zero Current Status ZIS Zero Current Status Query See Chapter 6 for additional IEEE 488 commands for the following MPS Options Model 6226 6476 LHe Level and Gaussmeter Input Card Paragraph 6 2 Model 6228 Persistent Switch Heater Output 2 2 eee Paragraph 6 3 COMMAND Shortcut Command Short command description Input Syntax of user input Returned Informational response to query Remarks Explanation and definition of informational response A9 Remote Operation 4 3 1 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Operational Commands Description Below is a list of MPS Operational Commands which configure the various functions ERR Input Returned Remarks IMAX Input Remarks IMAX Input Returned Remarks IOUT I Input Returned Remarks ISET I Input Remarks ISET Input Returned Remarks IV Input Returned Remarks Remote Operation Error Status Query ERR OVP RI STEP Returns 0 if t
131. onstants then sets the output voltage to 0 Verify a DVM reading of OV 0 1V before continuing the calibration 16 Connect DVM across current monitoring resistor Error Messages amp Troubleshooting S Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 17 Send IZER to force output current to 0 amps Verify a DVM reading of OV 0 01V Allow MPS output to settle for 2 minutes 18 Convert DVM voltage reading to current A reading of 0 000345V equals 0 345A Send actual current using CALZ xxx xxxx If actual current is 0 345 amps send CALZ 0 3450 The MPS determines the zero current calibration constant 19 Send ICAL50 to inform MPS of output current calibration and to force output current to 50 amps Verify a DVM reading of 0 05V 10 Allow MPS output to settle for 2 minutes 20 Convert DVM voltage reading to current A reading of 0 512345V equals 51 2345A Send actual current with CALPL xxx xxxx If actual current is 51 2345A send CALPL 51 2345 The MPS determines the positive current calibration constant 21 After the MPS determines the positive current calibration constant it automatically sets output current to the same value with the opposite sign Verify that the DVM reads 0 05V 10 Allow MPS output to settle for 2 minutes 22 Convert voltage reading from DVM to current A reading of 0 0487655V equals 48 7655A Send actual current with CALMN xxx xxxx If actual current is 48 7655A sen
132. ould be defined as above CB ADD 0 to 32 Control Bus Address Use the Data Entry up or down arrows to increment or decrement the Control Bus Address The initial condition is 0 B20 Mainframe Control Bus Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual B6 0 CONTROL BUS SERIAL INTERFACE OPERATION The host computer initiates the serial interface link and transmits either a command or a query to the Mainframe The Mainframe stores the characters in a buffer until the carriage return CR line feed LF terminator sequence After receiving the terminators the Mainframe responds appropriately to a query if present and stores the new input parameters Queries output requested data immediately following the processing of the command and terminator sequence If more than one query is sent the last query received is acknowledged Commands and queries can be sent in the same command string For example the command string ISET 10 VSET 10 updates the current setting to 10 amps and the voltage setting to 10 volts No query was sent therefore the Mainframe returns no response The command string ISET 10 VSET 10 ISET causes the Mainframe to return the current setting as well The serial interface shares device specific commands with the IEEE 488 interface Tables B 1 and B 2 summarize the commands See Chapter 3 of this manual for detailed command descriptions The END and TERM remote commands are IEEE 488 interf
133. play screen Wait 1 minute for MPS output to settle The DVM should read the same as recorded for Step 9 0 01 mV Set output current to 50 Amps The DVM should read about 33 mV After about 1 minute the DVM should read 33 333 mV 0 117 mV not including offset from Step 9 Models 622 623 ONLY Set output current to 100 Amps The DVM should read about 66 mV After about 1 minute the DVM should read 66 666 mV 0 233 mV not including offset from Step 9 Set output current to 50 Amps The DVM should read about 33 mV After about 1 minute the DVM should read 33 333 mV 0 117 mV not including the offset from Step 9 Models 622 623 ONLY Set output current to 100 Amps The DVM should read about 66 mV After about 1 minute the DVM should read 66 666 mV 0 233 mV not including the offset from Step 9 Set output current to 0 A Fault RI Operation Verification 18 19 20 Short the MPS RI input with a shorting jumper MPS output current should drop to 0 A and the alarm should sound about once per second Verify the MPS displays the RI screen shown in Paragraph 3 7 1 With the unit ON disconnect AC power connector The front panel circuit breaker should trip The performance verification is complete Error Messages amp Troubleshooting ST Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 5 5 REAR PANEL CONNECTOR DETAIL Figure 5 1 MPS Rear Panel Connectors MPS Rear Panel Connectors
134. plays the normal display Remote Inhibit Rl Detected The Remote Inhibit RI and Fault FLT indicators provide hardware fault indication and remote shutdown in addition to internal protection features The FLT indicator is a set of normally closed contacts when the unit is OFF When the unit is ON and no fault is present the contacts are open If the MPS detects a fault or an RI input assertion from an external contact closure it enters Remote Inhibit Mode forces output settings to 0 amps and 1 volt and turns ON the front panel Fault annunciator The MPS closes the FLT contacts to indicate a fault sounds the alarm once per second and displays The alarm stops sounding when RI is removed but the MPS continues to display RI until the user enters new output settings then turns them OFF This latching action informs the user of RI activity When the MPS detects no RI input activity it turns OFF the front panel Fault annunciator and internal alarm and opens the FLT contacts When the MPS software detects open FLT contacts RI is inactive it displays the Normal Display To insert a 2 to 3 second delay between RI activation and the initial fault operation turn CAL AND ID switch 7 ON up the MPS polls for RI activity after the delay If RI is still active the fault operation continues if not it is ignored In multiple MPS configuration if an external contact closure activates the MPS RI indicators the MPS units e
135. pon detection of an execution error Occurs when the instrument is instructed to do something outside its capabilities Device Dependent Error DDE Bit 3 Reserved for future use Query Error QYE Bit 2 Indicates a query error Occurs rarely and involves loss of data due to a full output queue Operation Complete OPC Bit 0 Generated in response to the OPC operation complete common command It indicates MPS completion of all selected pending operations 4 1 4 Example IEEE Setup and Program Below is an example of how to setup and run a simple program using the built in MPS IEEE 488 Interface It does not reflect every hardware software configuration found in the field This example uses the National Instruments GPIB PCII IIA card and QuickBasic 4 0 or 4 5 on a PC compatible 4 1 4 1 GPIB Board Installation Use the following procedure to install the GPIB Board 1 Install GPIB PCII IIA card using National Instruments instructions 2 Install NI 488 2 software for DOS Version 2 1 1 was used for the example 3 Verify that config sys contains the command device C GPIB COM 4 Reboot the computer 5 Run IBTEST to test software configuration Do not install the instrument before running IBTEST 6 Run IBCOMF to configure the GPIB PCII IIA board and dev 12 Set the EOS byte to OAH See setup in Fig 4 1 IBCONF modifies gpib com 7 Connect the instrument to the interface board and power up the instrument Verify th
136. put PSHS Returned PSH PSH status PSH compliance current value command status where PSH 0 if PSH is present or 1 if PSH is not present PSH heater status 0 if heater is OFF or 1 if it is ON PSH compliance 0 if PSH is under compliance or 1 if it is over current value up to three characters which give the current value command status 0 if the command status is OFF or 1 if it is ON Remarks Returns seven characters plus up to two terminators PSHCH Program PSH Channel Multiplex PSH Card ONLY Input PSHCH channel where channel 0 to 8 Returned Nothing Remarks Command applies to the Model 6228 8MUX Card ONLY 0 heater OFF 1 to 8 heater ON PSHCH PSH Channel Query Multiplex PSH Card ONLY Input PSHCH Returned Channel number from 0 to 8 Remarks Command applies to the Model 6228 8MUX Card ONLY 0 heater OFF 1 to 8 heater ON Returns one character plus up to two terminators 6 4 MODEL 6228 2 PERSISTENT SWITCH HEATER OUTPUT The Model 6228 2 Persistent Switch Heater Output Option controls a second Persistent Switch The output has the same specifications as the 6228 card The PSH SETUP screen using a 6228 and a 6228 2 card appears to the right Only the heater currents can be changed on this screen The status of the heater is either on or off The last value is the current of the power supply when the heater was last turned off The PSH SETUP screen using a 6228 8MUX and a 6228 2 card
137. r maintenance procedure which if not strictly observed may result in injury death or long term health hazards to personnel CAUTION An operation or maintenance procedure which if not strictly observed may result in equipment damage destruction or loss of effectiveness NOTE Emphasizes an operation or maintenance procedure GENERAL INSTALLATION PRECAUTIONS These recommended general safety precautions are unrelated to any specific procedure and do not appear elsewhere in this manual Personnel should understand and apply these precautions during installation Installation personnel shall observe all safety regulations at all times Keep away from live circuits Turn off system power before making or breaking electrical connections Regard any exposed connector terminal board or circuit board as a possible shock hazard Discharge charged components only when such grounding cannot damage equipment If a test connection to energized equipment is required make the test equipment ground connection before probing the voltage or signal Do not install or service equipment alone Do not under any circumstances reach into or enter any enclosure to service or adjust equipment without the presence or assistance of another person able to render aid ELECTROSTATIC DISCHARGE Electrostatic Discharge ESD may damage electronic parts assemblies and equipment ESD is a transfer of electrostatic charge between bodies at different electrostatic pote
138. r ratings of the individual units Assign each unit a unique address 1 for MPS 1 2 for MPS 2 etc The MPS at address 1 polls the control bus to determine if an auto parallel configuration is present and how many MPS units are involved When multiple MPS units are present MPS 1 sends the output current and voltage limits ramp status output current step limit and other operating parameters to the other MPS units so all units operate identically For two MPS configuration each MPS is programmed for half of the total output current This is true for the ramp destination current and ramp rate Each MPS contributes half the output current required MPS 1 software polls MPS 2 to determine the total output current The output voltage current settings during a ramp and instrument status from MPS 1 are reported since the values are the same for both units NOTE When multiple MPS units are present install the Model 6228 persistent switch heater output option in MPS 1 for proper operation An analog signal is also provided for remote activation of the output over voltage protection OVP circuit The signals connect in parallel so that the output OVP circuits of each MPS activate in unison CAUTION Consult Lake Shore prior to operating multiple MPS units in auto parallel mode Use the procedure below and see Figure 2 4 to connect multiple MPS units in auto parallel configuration 1 Turn off all units and completely disconnect power at the source
139. r returns to the AC line instead of dissipating through an energy absorber Low Noise High Stability Current Regulation Analog output control uses a precision shunt for current stabilization to better than 50 PPM of full scale current over an 8 hour period 50 A 5 V Model 620 125 A 30 V Model 622 155 A 30 V Model 623 or 72 A 32 V Model 647 Constant Current Output 1 Programming resolution for Models 620 622 647 is 1 0 mA and 1 mV 2 Programming resolution for the Model 623 is 1 2 mA and 1 mV No current reversal switch required Output current reversal is smooth and continuous with excellent near zero current performance Remote and local sensing of output voltage Compensates for voltage drops in the output leads Quiet switched mode design Results in a highly efficient lightweight unit capable of air cooling Front Panel Graphic Display Allows continuous display of output while setting parameters from the menu driven keypad Operating parameters that can be set and monitored are Output current and compliance setting Output current and voltage measurement Output current step limiting Output current zeroing Output ramp programming Status reporting Persistent switch heater control with optional Model 6228 Card Liquid Helium level and Field monitoring with optional Model 6226 6476 Card Four methods of setting and monitoring all operating parameters 1 From front panel 2 From remot
140. rear panel Turn ON up position switches 2 and 4 Turn OFF down position switches 1 3 and 5 through 8 Switch 4 ON designates Multiple MPS operation Switches 3 2 and 1 as OFF ON OFF respectively assign the MPS address as 2 b Move the MODE switch to the INTernal up position c On the CMP verify that switches 5 6 and 7 are ON closed and switches 1 through 4 and 8 are OFF OPEN Replace the CMP 4 Connect the control bus Use Lake Shore Model 2001 Modular Cables provided to interconnect the two MPS CMP units Connect the MPS 1 over voltage protection OVP pin 8 to MPS 2 pin 8 Connect the RI and FLT signals Connect the RI terminal 1 to the FLT terminal 3 on MPS 2 Connect the Hl terminal 2 to the FLT terminal 4 on MPS 2 Do the same on MPS 1 Connect the RI FLT connection of MPS 2 to the RI FLT connection of MPS 1 Connect the RI FLT connection of MPS 2 to the RI FLT connection of MPS 1 If an external contact closure will remotely inhibit operation connect it across the RI and RI terminals of MPS 1 The FLT and FLT contact closure of MPS 1 indicates a fault 7 Connect the OUT terminal of MPS 1 to the OUT terminal of MPS 2 Connect the OUT terminal of MPS 1 to the OUT terminal of MPS 2 Make these leads as short as possible to minimize output potential differences between the two MPS units and large enough to handle the maximum MPS current Connect the output terminals to the load using
141. rol Bus Remote Command Summary Input ESE ESR IDN SRE Clear all pending status Event status register enable Event status register contents Product identification Service request status byte enable STB Status byte register contents TST Self test error status MODE IEEE interface mode status not used TERM IEEE interface terminator status Terminators fixed at CR LF 1 ISET Output current setting V VSET Output compliance voltage setting IOUT Output current measurement VOUT Output voltage measurement Output current voltage status byte and programming mode IMAX Maximum output current setting limit RAMP Ramp segment parameter programming SEG Active ramp segment fixed at 1 RMP Ramp active enable and status Mainframe digital calibration ZI ZIS Output current zero setting Output current zero enable and status IMODE Current programming mode switch status VMODE Voltage programming mode switch status Wee ee WS RES Normal or high resolution status This command is obsolete It is Eo teeny ol Ke retained to maintain compatibility with older MPS units Output overvoltage protection status Error Status Remote inhibit status Output current step setting Output current step enable and status Output current step status reset OVP ERR RI ISTP ISTP ISTPS ISTPS Mainframe Control Bus Operation B 5 B 6 Lake Shore Mo
142. s an energy source It turns OFF the front panel Power annunciator and turns ON the front panel Fault annunciator It closes the FLT contacts to indicate a fault and sounds the alarm about once per second The MPS sets output voltage compliance to the level required to maintain operation and continuously monitors output current If the utility recovers the MPS enters Remote Inhibit Mode and forces output settings to 0 amps and 1 volt If the utility does not recover the MPS activates the output OVP circuit and turns OFF the front panel circuit breaker when the output current drops below 10 amps Upon power down the MPS enters AC Loss Mode NOTE A utility loss while the MPS returns energy from a charged load to the utility presents no hazard to personnel working on the utility circuit The MPS is not a UPS It uses the utility voltage wave form to draw energy from the utility with a sinusoidal current and return energy to the utility with a sinusoidal current If there is no utility reference signal the MPS disables utility input circuitry and uses the load for energy If utility loss occurs during normal operation in a multiple MPS configuration the MPS detecting the utility loss initiates Multiple MPS Remote Inhibit Mode by closing the FLT contacts and turning off the front panel circuit breaker Then the remaining MPS units enter Multiple MPS Remote Inhibit Mode Error Messages amp Troubleshooting Lake Shore Model 620 622 623 647
143. sistence Switch Heater card of the MPS supplies a current to a resistance heating element to normal a persistence wire opening the ends of a supercooled magnet to enable charge current change Program current from 0 to 124 mA through the PSH Setup screen Three conditions must be met when selecting an appropriate current 1 The current must be enough to normal the switch element The magnet manufacturer specifies this current and the heater resistance This current must fall between the two following extremes 2 The selected current multiplied by the heater resistance e i x r must be greater than 0 65 Vdc for the MPS to accurately determine switch status when heated If less than 0 65 Vdc the MPS may not properly report switch mode 60 Options amp Accessories Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 The selected current multiplied by the heater resistance e i x r must be less than 15 Vdc for the MPS to accurately determine compliance of the switch heater open resistance Examples A 100 ohm heater resistance set for 100 mA yields 10 volt compliance Ohm s Law This is greater than the required 0 75 Vdc and yet less than 15 Vdc This allows proper performance A 10 ohm heater resistance set for 50 mA yields 0 5 Vdc less than the minimium for acceptable operation The MPS cannot reliably determine the switch status and may report erroneously in some conditions The best solution is to raise t
144. small offset current may result in high energy stored in the magnet load The output current zero feature allows the user to zero this output current offset The MPS stores the current zero value in non volatile memory Before accessing output current zero from the MPS front panel enter a current of zero and allow the output current to settle to the offset value If the status is ON toggle it OFF and allow current to settle to clear the old value before entering a new value When the status is toggled ON the MPS stores the output current as the current zero and displays it as the ZERO value 3 6 1 4 Instrument Setup Screen The Instrument Setup screen defines the major operating characteristics of the Normal Display Press the Function Menu key to display Function Menu 1 Press the INSTR SETUP Function key to display the Instrument Setup screen to the right Use the Cursor keys to move the line indicator up or down Parameters with a icon toggle with the Data Entry up or down key Change all others using any numeric entry mode including the cursor NOTE FLD ENABLE B UNITS and FIELD A apply to superconducting magnets where there is a linear relationship between current and field Do not confuse this with the Model 6226 Gaussmeter Card reading This is a computed field directly related to the current by the constant entered on the fourth line FLD ENABLE lt ON gt or lt OFF gt Field Enable Allows the user to change the Normal Displ
145. ster Query Input ESE Returned An integer between 000 and 255 Remarks Reads the Standard Event Status Register The integer returned represents bits set in the Service Request Enable Register It is a sum of the bit weighting of each bit set This Query supplies various error conditions and whether the MPS has been powered off and on since the last query Returns three digits plus up to two terminators Jm Remote Operation IDN Input Returned Remarks OPC Input Returned Remarks OPC Input Returned Remarks RST Input Returned Remarks Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Identification Query IDN Manufacturer Model Number Model Serial Number Firmware Date Returns seventeen characters plus up to two terminators Example LSCI 622 0 120193 term Operation Complete Status OPC Nothing Causes the MPS to set an update cycle counter to 2 Each time through an update cycle parameters entered by device dependent commands update and the cycle count decrements Two update cycles complete all pending device dependent commands When this occurs the MPS sets the operation complete bit in the Standard Event Status Register not the IEEE 488 2 defined operation Not supported by Control Bus Operation Complete Status Query OPC 0 or 1 where 0 indicates incomplete 1 indicates complete Places 1 in the instrument output queue and sets t
146. system of three Function Menus for setup Function Menus 1 and 2 do not require a PSH Option Card but the presence of one changes the look of the menus The Function Menu 3 requires a PSH Option Card in order to display Press Function Menu to display Function Menu 1 To choose a different menu press Next Menu Function Menu 2 displays Each press of Next Menu displays the next menu Pressing Next Menu with Function Menu 3 displayed returns to Function Menu 1 To exit a Function Menu press Function Menu To exit the menu system press Normal Display or Escape See Figure 3 1 3 6 1 Function Menu 1 Function Menu 1 for an MPS with a PSH Option Card appears to the right The 1 3 in the upper right corner indicates Menu 1 of 3 It has four selections AUTOMATIC MODE MANUAL MODE INTERFACE SETUP STEP LIMIT ZERO and INSTR SETUP 3 6 1 1 Automatic Mode Manual Mode AUTOMATIC MODE appears in the menu only on MPS units with a PSH Option Card installed and operating in MANUAL MODE Without a PSH Option Card this menu item is empty and a 1 2 appears in the upper right corner indicating menu 1 of 2 If the PSH option is installed then the menu item toggles between MANUAL and AUTOMATIC PSH control If the unit is in MANUAL MODE this menu item reads AUTOMATIC MODE and pressing the corresponding Display Function key places the MPS in AUTOMATIC PSH control mode If the unit is in AUTOMATIC MODE this menu item reads MANUAL MODE and pressing
147. t Mainframe serial interface jacks a Model 2001 cable plugs into the other first Mainframe serial interface jack to connect to the second Mainframe and so on Connect up to 32 Mainframes in this way Terminate the last Mainframe only if it is a significant distance from the host Assign unique addresses to multiple Mainframes on a RS 485 interface 4 Replace the CMP B5 0 SELECTING THE CONTROL BUS SERIAL INTERFACE ADDRESS Multiple Mainframes on the RS 485 interface each have a unique address and operate in a polled mode Set the MPS Mainframe to respond to one of 32 addresses Prefix all commands sent to a Mainframe with the Mainframe address A Mainframe query response includes the address prefix if the address is not 0 The receipt of the LF OAH terminator resynchronizes communications and alerts all Mainframes that the next character is an address A Mainframe with address 0 responds to all commands on the interface A Mainframe using RS 232C can be given a unique address as well but RS 232C is not suited for multi drop operation Access the Control Bus serial interface address from the Interface Setup screen Press the Function Menu key to display Function Menu 1 Press the key corresponding to INTERFACE SETUP to display the Interface Setup screen Use the cursor key to move to the line indicating CB DEF and CB ADD defined as follows CB DEF 9600 Baud No Parity 8 Data Bits and 1 Stop Bit Control Bus Definition The control bus sh
148. t Status Register and terminates all pending operations The instrument related command is RST ESE Enables Status Reports In The Standard Event Status Enable Register Input ESE bit weighting where bit weighting the sum of the bit weighting of each bit to be set The value can be 000 to 255 See the discussion on registers and below Remarks Each bit is assigned a bit weighting See the format of the Standard Event Status Register given below to see bit weighting and register placement Further explanation of each bit is discussed in the register section following the Common Command Table See Paragraph 4 1 3 2 for a complete description of status bits 7 6 4 3 2 1 Ip 128 64 32 16 a 4 2 1 Weighting PON ive CME EXE DDE QYE OPC Bit Name Example To set a bit send the command ESE with the sum of the bit weighting for each bit desired For example to set bits 0 3 4 and 5 send the command ESE5 57 is the sum of the bit weighting for each bit Bit Weighting 1 0 3 8 4 16 5 32 57 ESE Standard Event Status Enable Query Input ESE Returned An integer between 000 and 255 Remarks Reads the Standard Event Status Enable Register The integer returned represents the bits set in the Standard Event Status Enable Register It is a sum of the bit weighting of each bit set Returns three digits plus up to two terminators ESR Standard Event Status Regi
149. t mode Without an PSH option installed the MPS powers up in the Normal Display for Manual Mode Set Magnet Ramp Rate and Persistence Switch Ramp Rate in the Normal Display screen Set Field Units Maximum Current and Compliance Voltage in the Instrument Setup Screen Set Current Step Limit in the Step Limit Zero screen CAUTION Set magnet parameters according to manufacturer s specifications Failure to do so may damage the magnet and threaten user safety 3 3 NORMAL DISPLAY FOR MANUAL MODE Shown to the right is the default startup Normal Display for Manual Mode For operation with the PSH card installed see Paragraph 3 4 for MANUAL persistence mode or Paragraph 3 5 for AUTOMATIC persistence mode The Normal Display screen allows entry of MPS output current or field settings at any time Settings cannot exceed limits in the INSTRUMENT SETUP screen The OUTPUTS portion of the screen indicates output values and computer interface status The Normal Display key returns the display to this screen at any time Use the Cursor keys to move the line indicator up or down Parameters with a icon toggle with the Data Entry up or down key Change all others using any numeric entry mode including the cursor CURRENT FIELD MPS Output Setting This line reads CURRENT if set to display amps and FIELD if set to display computed field see Paragraph 3 6 1 4 To set MPS output move to the CURRENT FIELD line and enter the new setting
150. the instrument to an authorized Lake Shore Cryotronics Inc representative for service and repair to ensure that safety features are maintained Dangerous Procedure Warnings A WARNING heading precedes potentially dangerous procedures throughout this manual Instructions in the warnings must be followed Forward vii Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual SAFETY SYMBOLS viii OSF ee Direct current power line Alternating current power line Alternating or direct current power line Three phase alternating current power line Earth ground terminal Protective conductor terminal Frame or chassis terminal On supply Off supply Equipment protected throughout by double insulation or reinforced IO insulation equivalent to Class II of IEC 536 see annex H Caution High voltages danger of electric shock Background color Yellow Symbol and outline Black Caution or Warning See instrument documentation Background color Yellow Symbol and outline Black Forward Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTER 1 INTRODUCTION 1 0 GENERAL This chapter covers Features Paragraph 1 1 Specifications Paragraph 1 2 and Operating Characteristics Paragraph 1 3 1 1 FEATURES True Four Quadrant Bidirectional Power Flow Operate current or voltage as a source or a sink in either positive or negative polarities Sink powe
151. the cycle once it stores the ending current value to LAST END To make subsequent changes to magnet current simply enter a new MGT END setpoint To pause a ramp or skip a time out press either the Data Entry up or down key To abort the operation press Escape After an abort lt RUN gt continues an automatic process from where it left off activate Automatic Mode S dan SHOR 5 ee The MPS automatically runs g 25 END ON through the cycle as defined S Delay Delay providing messages on the Sot a T bottom line of the display to S detail the current step of the RAMP PERS z 15 UP OFF cycle When complete the S Delay Delay 6 wn Q MGT RATE Ramp 25 30 Time seconds 35 40 45 50 57 5 Persistence Mode Status Figure 3 2 Typical Automatic Mode Cycle 3 10 Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 3 9 DITHERING IN AUTOMATIC MODE Dithering is a means of arriving at the magnet current by executing excursions around the final current which decay to zero in a specified dwell delay time For example suppose the final magnet current MGT END is 100 amperes the maximum dither is 0 5 and the Dither Delay is 30 seconds The operation in the Automatic Mode proceeds the same as in Paragraph 3 8 up to the time that the magnet current ramps The current in the magnet ramps to 100 1 0 005 100 5 amperes which is 0 5 above the final magnet current Wh
152. the value returned is 0 Heater ON means persistence is OFF Returns one character plus up to two terminators PSH Compliance Status Query PSHBC 0 if PSH output is under the output compliance limit or 1 if the output is over the limit Returns one character plus up to two terminators Current Setting When PSH Was Turned Off PSHBIS The value returned is a number between 125 0000 A Returns nine characters plus up to two terminators PSH Summary Query PSHBS PSHB PSHB status PSHB compliance current value command status where PSHB 0 if PSH is present or 1 if PSH is not present PSHB heater status 0 if heater is OFF or 1 if it is ON PSHB compliance 0 if PSH is under compliance or 1 if it is over current value up to three characters which give the current value command status 0 if the command status is OFF or 1 if it is ON Returns seven characters plus up to two terminators 6 13 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 6 5 ACCESSORIES Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit Below are MPS accessories mem tense zo vac egenen mem Immens Camas mem eremm tne era Euope gg a RJ 11 Cable Assembly Four Wire Cable Assembly with RJ 11 plugs on each end Used with RS 232C Interface Cable is 14 feet 4 6 meters long See Figure 5 4 am RJ 11 to DB 25 Adapter Adapts RJ 11 receptacle to femal
153. ther Operation 3 11 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual This Page Intentionally Left Blank Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual CHAPTER 4 REMOTE OPERATION 4 0 GENERAL Either of two computer interfaces on the optional 6224 card permit remote MPS operation the IEEE 488 Interface Paragraph 4 1 and the Serial Interface Paragraph 4 2 Use only one of the interfaces at a time The two interfaces share a common set of commands described in Paragraph 4 3 For further information on RS 485 Mainframe Control Bus Operation see Appendix C 4 1 IEEE 488 INTERFACE The IEEE 488 Interface is an instrumentation bus with hardware and programming standards that simplify instrument interfacing The MPS IEEE 488 Interface complies with the IEEE 488 2 1987 standard and incorporates the functional electrical and mechanical specifications of the standard 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 MPS performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is the digital computer which tells the MPS which
154. tial condition is 00 0000 V The voltage setting is always forced to a Control Bus inputs 4 places display rounds to 0 01 or 0 001 place Compliance Voltage Setting Query VSET A number between 0 and 5 000 V 620 0 and 30 000 V 622 623 or 0 and 32 000 V 647 Returns nine characters plus up to two terminators Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 3 2 Interface Commands Description The MPS Interface Commands below help configure IEEE 488 interface compatibility for a variety of computer equipment END Input Remarks END Input Returned Remarks MODE Input MODE Input Returned Remarks TERM Input Remarks TERM Input Returned Remarks Programs MPS Interface EOI End Or Identify Status END status where status 0 to enable the EOI or 1 to disable it When enabled the hardware EOI line becomes active with the last byte of a transfer Not supported by Control Bus End Of Identify EOI Query END 0 if EOI is enabled or 1 if it is disabled Returns 1 character plus up to 2 terminators Not supported by Control Bus Programs MPS Interface Mode Status MODE status where status 0 for local mode 1 for remote mode or 2 for remote mode with local lockout Supported in Control Bus operation Interface Mode Status Query MODE 0 for local mode 1 for remote mode or 2 for remote mode with local lockout R
155. tions e A Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 2 4 1 Power and Ground Requirements The AC power source for the MPS should be frequency and voltage regulated and isolated from sources that may generate Electromagnetic Interference EMI The MPS is designed for single phase 3 wire alternating current AC power do not use two wire without ground AC power Lake Shore recommends Ground Fault Interrupter GFI and Transient Surge Protection circuitry at the AC source In areas where AC voltage varies consider using a constant voltage transformer For power outages consider using an Uninterruptible Power Supply UPS CAUTION Do not attempt to apply electrical power until the MPS is checked for proper line voltage settings Factory preset MPS line voltage requirements allow proper operation at the shipping destination The line voltage setting is indicated on the rear panel Before applying power to the main input power cable check for correct input power settings for the power source voltage Ground the instrument panels and cabinets The safety ground provides a true ground path for electrical circuitry and in the event of internal electrical faults such as shorts carries the entire fault current to ground to protect users from electrical shock The MPS has a three conductor power input connector which grounds the MPS chassis when plugged into a 3 wire receptacle EMI is both a natural and man made electr
156. tor must be AWG 16 or larger Larger wires may be required to prevent excessive voltage drop in the AC power lines if the unit is located an extended distance from the main AC distribution terminals WARNING For proper circuit breaker protection mate the wire connected to the L terminal of the connector to the L hot side of the line and mate the wire connected to the N terminal to the N neutral side of the line Mate the wire connected to the GND terminal to earth ground Do not operate this instrument without an adequate ground connection CAUTION Before applying power to the MPS verify that the AC source matches the line voltage listed on the rear panel NOTE Make connections to the AC power line in accordance with applicable electrical codes The international color code for identifying utility supply conductors is green yellow for earth GND blue for neutral N and brown for line L The US and Canadian codes are green for earth GND white for neutral N and black for line L Setup amp Connections Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual Use this procedure to connect input power to the MPS 1 Loosen the two connector cover screws and open the cover 2 Slip the strain relief over the power cable with the flanged end at the end to be terminated 3 Attach the wires to the connector in accordance with prevailing color codes green or green yellow t
157. ume an initial MPS hook up to this magnet and a previous magnet charge to 20A MGT END Magnet End Current Enter 30 A MGT RATE Magnet Charging Rate Base this figure on the maximum magnet current supplied by the magnet manufacturer For this example enter 0 4 A S amperes per second PERS RATE Persistence Switch Charging Rate Base this figure on the maximum Persistence Switch current generally much higher than the magnet charging rate Anything over approximately 20 A S appears instantaneous For this example enter 4 A S 3 Enter the following parameters in the Automatic Delay Screen Function Menu 3 RUN UP The time between initial ramp up to current and PSH activation Persistence Mode OFF Enter 5 seconds PERS OFF The time between PSH activation Persistence Mode OFF and initial ramp to setpoint Enter 5 seconds RAMP END The time between ramp up to setpoint and PSH deactivation Persistence Mode ON Enter 5 seconds PERS ON The time between PSH deactivation Persistence Mode ON and initial ramp back to zero Enter 5 seconds 4 Return to the Automatic Mode Screen Move to the RUN line then toggle to 29 MGT Persist O LAST AUTOMATIC MODE MGT RE n ASI 35 PERS RATE Ramp display returns to STANDBY After determining proper system 5 Delay times it is unnecessary to visit the Delay Screen each time the delays store in non volatile memory After the MPS completes
158. ve the arrow indicator to RS232C Press the Data Entry up or down arrows to cycle between 300 1200 or 9600 Baud The remainder of the parameters are fixed at No Parity 8 Data Bits and 1 Stop Bit 4 2 3 Sample BASIC Serial Interface Program The QuickBASIC V4 0 program in Table 4 3 is a sample interactive serial poll routine for the MPS Serial Interface Below are typical examples using this BASIC program User input is in bold type ENTER COMMAND IDN Identification Query Returns manufacturer model number 0 and Firmware Date LSCI 622 0 120193 ENTER COMMAND ISET 25 I0UT Output Current Setting and Query Instructs unit to set current to 25 amps and then asks for current reading 24 9975A ENTER COMMAND OVP Overvoltage Quench Protection Circuit Status Query Unit returns setting where 0 Off and 1 On 0 ENTER COMMAND RI Remote Inhibit Status Query Unit returns setting where 0 Inactive and 1 Active 0 ENTER COMMAND MODE Mode Status Query Instrument returns mode where 0 Local 1 Remote or 2 Remote with Lockout 1 28 Remote Operation Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual 4 2 4 Notes On Using The Serial Interface e To chain commands together insert a semi colon between them Multiple queries cannot be chained e Queries use the same syntax as the associated setting command followed by a question mark They usually return th
159. ve the line indicator The icon indicates parameters changed only with the Data Entry up and down arrows Change all others using all the numeric entry modes including the cursor HEATER XXX mA PSH Heater Current Use any numeric entry mode to change the value from 0 to 999 mA STATUS lt OFF gt or lt ON gt PSH Status Use the Data Entry up or down arrows to toggle the status LAST END 0 000 A Last Current Setting This value is the current setting when the PSH was turned off This value is retained in non volatile memory so that the output current can be set to the magnet current when the PSH is turned on Options amp Accessories ss i lt i s lt O 69 Lake Shore Model 620 622 623 647 Magnet Power Supply User s Manual When PSH is ON the MPS compares the present current setting with the current setting stored when PSH was OFF If the two do not match the MPS sounds the alarm for 2 second and displays Press a Data Entry up or down arrow to turn ON the PSH If Esc is pressed or no key is pressed for approximately 30 seconds the PSH is not turned ON 6 3 3 Model 6228 8MUX Operation The 6226 8MUxX is a persistence card with a multiplexed output The output specifications are the same as the single 6228 option card The heater supply current connects to one of eight persistence heaters The PSH SETUP screen displays an additional line indicating the channel active if the heater

Lakeshore Learning Materials 622 User's Manual

Contents

Download Pdf Manuals

Related Search

Related Contents