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Model 420 Model 420 - Lake Shore Cryotronics, Inc.

1. CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may need more BAUDS 9600 TERMS CHR 13 CHR 10 Terminators are lt CR gt lt LF gt OPEN COM1 BAUDS 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 RSS vian If query read response N Clr return string and count WHILE N lt TIMEOUT AND INSTR RSS 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 RSS MIDS RSS 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 4 4 Remote Operation Lake Shore Model 420 Gaussmeter User s Manual 4 2 SERIAL INTERFACE COMMAND SUMMARY There are two command groups Interface Commands Paragraph 4 2 2 and Device Specific Commands Paragraph 4 2 3 Command Function Command Function Interface Commands M
2. 3 1 1 Front Panel Keypad Definitions LakeShore 420 Gaussmeter Gauss Tesla Relative AC DC C 420 U 1 1 Figure 3 1 Model 420 Front Panel Max Reset Works with Max Hold function Returns Max reading to normal field reading See Paragraph 3 2 Max Hold Turns Max Hold feature ON and OFF Captures and displays the highest field reading Use Max Reset key to clear reading See Paragraph 3 2 Zero Probe Zeros or nulls effects of ambient low level fields from the probe To use place tip of probe into Zero Gauss Chamber and press Zero Probe Display returns to normal readings in about 5 seconds See Paragraph 3 3 Range Selects manual field measurement range or Autorange Available ranges depend on which probe is installed There is a slight delay until the unit settles on the proper range See Paragraph 3 4 AC DC Selects periodic AC or static DC magnetic fields The AC selection provides RMS readings See Paragraph 3 5 Gauss Tesla Changes display units from gauss to tesla Gauss G is used in the cgs system where 1 G 10 T Tesla T is used in the SI system where 1 T 104 G See Paragraph 3 6 Interface Adjusts the baud rate to 300 1200 or 9600 during serial interface See Paragraph 3 7 Relative Displays the positive or negative deviation from setpoint in the lower line of the display Often used to offset large magnetic fields May also be used with Max Hold and Alarm See Paragraph 3 8 Operation 3
3. 1 4 Introduction Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 2 INSTALLATION 2 0 GENERAL This chapter covers general Model 420 installation instructions Inspection and Unpacking Paragraph 2 1 Repackaging for Shipment Paragraph 2 2 Definition of Rear Panel Connections Paragraph 2 3 and Initial Setup and System Checkout Procedure Paragraph 2 4 2 1 INSPECTION AND UNPACKING Inspect shipping containers 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 please notify the shipping agent immediately Open the shipping containers Use the packing list included with the system to verify receipt of the instrument sensor accessories and manual Inspect for damage Inventory all components supplied before discarding any shipping materials If there is freight damage to the instrument file proper claims promptly with the carrier and insurance company and notify Lake Shore Notify Lake Shore immediately of any missing parts Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment See the standard Lake Shore Warranty on the A Page immediately behind the title page 2 2 REPACKAGING FOR SHIPMENT To return the Model 420 sensor or accessories for repair or replacement obtain a Return Goods Authorization RGA number from Technical Se
4. Lake Shore Model 420 Gaussmeter User s Manual 1 2 1 Identification of Electrostatic Discharge Sensitive Components Below are various industry symbols used to label components as ESDS H A Bee 1 2 2 Handling Electrostatic Discharge Sensitive Components Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and everything that contacts it to ground potential by providing a conductive surface and discharge paths As a minimum observe these precautions 1 Deenergize or disconnect all power and signal sources and loads 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 ina 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 from the packages until actually used or tested 1 3 SAFETY SUMMARY Observe these general safety precautions during all ph
5. Number Area Material Range yp of Z e O MFT 3E03 VH 3E03 VH R 0 09 G C 0 015 C 0 15 i Flexible DC 10 to to 30 kG 0 13 G C 0 005 C Tubing 400 Hz 0 50 to 30 kG 0 0 25 o of j MFT 2903 VH to 30 kG 0 13 G C 0 005 C MFT 3E03 VG MFT 2903 VJ 0 09 G C 0 015 C This table is for L 15 inches and S 0 75 inch Corrected Operatin Temperature Coefficient Model Active Stem Frequency Accuracy Tem E maximum Number Area Material Range of Range Reading Zeo Calibration Tubing aaa 0 09 G C 0 015 C 0 150 ang DC 10 to to 30 kG 0 0 015 max T Fiber 400 Hz 0 15 S S MFT 4F 15 VG glass 2 to 30kG 0 13 G C 0 005 C MFT 4F15 VH 4F15 VH Tubing C 450 U 6 10 Figure 6 10 Definition of Lake Shore Flexible Transverse Probes mme Around large solenoids measure small variations or low values of large volume magnetic fields such as that of the T wi earth or fringe fields with ultra high sensitivity probes Resolutions of several gammas 105 gauss to tens of gammas are available depending on the mating SE Active Sensing Length Ae gaussmeter a Optimum application for homogeneous fields over lengths Cable Length A gt 1 foot The active sensing length of the gamma probe is 6 6 feet To Center of about 3 125 inches Active Volume Corrected Temperature Coefficient Operating H Model T L Freq
6. The zero probe function cancels out the zero offset of the probe or small magnetic fields It is normally used in conjunction with the zero gauss chamber but may also be used with an unshielded probe registering the local earth magnetic field To cancel large magnetic fields use the Relative function NOTE For best results allow the instrument and probe to warm up for at least 5 minutes before zeroing the probe and at least 30 minutes for rated accuracy The probe and the zero gauss chamber should be at the same temperature To zero the probe in the zero gauss chamber first allow the temperature of the probe and chamber to equalize A large temperature discrepancy affects the quality of the calibration Carefully place the probe tip into the chamber Probe orientation is not critical Once inserted press Zero Probe to display the screen to the right Press Zero Probe again to display the CALIBRATING message followed by the normal display Do not move the probe while calibrating The probe is now zeroed For best results periodically zero the probe 3 2 Operation Lake Shore Model 420 Gaussmeter User s Manual 3 4 SELECT RANGE AND AUTO RANGE The Model 420 reads each Lake Shore probe type High Stability High Sensitivity or Ultra High Sensitivity These probes sense fields as low as 0 2 mG and as high as 300 kG The tables below list full scale ranges for each probe sensitivity along with fixed display resolution
7. Appendix A A 1 Lake Shore Model 420 Gaussmeter User s Manual This Page Intentionally Left Blank Appendix A Lake Shore Model 420 Gaussmeter User s Manual APPENDIX B HALL GENERATORS B1 0 GENERAL This chapter covers useful information about Hall Generators including Theory of Operation Paragraph B2 0 Generic Hall Generator Hookup Paragraph B3 0 Hookup to a Model 420 Gaussmeter Paragraph B4 0 Specifications Paragraph B5 0 and the HALLCAL EXE Program Paragraph B6 0 Obtain additional installation and calibration information in Lake Shore Document Number C2S001 B2 0 THEORY OF OPERATION E H Hall discovered the Hall effect in 1879 For nearly 70 years it remained a laboratory curiosity Finally development of semiconductor and ceramic material brought Hall generators into the realm of the practical A Hall generator is a solid state sensor which provides an output voltage proportional to magnetic flux density The device relies on the Hall effect which is the development of a voltage across a sheet of conductor placed in a magnetic field with current flowing See Figure B 1 Electrons the majority carrier most often used in practice drift in the conductor when under the influence of an external driving electric field When exposed to a magnetic field these moving charged particles experience a force perpendicular to both the velocity and magnetic field vectors This force charges the conductor edges one sid
8. High Stability Probe High Sensitivity Probe Ultra High Sensitivity Probe tesla ges ee testa Range Res Range Res Range Res Range Res Range Res Range Res For manual ranging press Range and select one of the full scale ranges displayed The display to the right appears Press Range to cycle through allowable full scale ranges for the installed probe To accept the new range either wait about 6 seconds until the display disappears automatically or press any key other than Range In Auto Range mode the Model 420 selects the range with the best resolution for the measured field It can take up to 2 seconds for Auto Range to work so manual ranging may be better sometimes Press Range until the screen to the right displays To accept the new range either wait about 6 seconds until the display disappears automatically or press any key other than Range Do not use Auto Ranging with Max Hold operation or during small field measurement in a large background field such as measuring a small DC field in presence of a large AC field or vice versa 3 5 AC DC The AC DC key toggles between AC and DC measurements The annunciator immediately changes from DC to RMS as applicable One update cycle is required for a new display value In DC operation the display shows the DC field at the probe with sign orientation followed by the appropriate field units and the letters DC The DC value is
9. Serial Interface Connector configured as DTE If the interface is DCE a Null Modem Adapter is required to exchange Transmit and Receive lines LSCI Model 4001 RJ 11 Cable Assembly C 420 U 4 2 Figure 4 1 Serial Interface Adapters Remote Operation 4 1 Lake Shore Model 420 Gaussmeter User s Manual 4 1 1 Serial Interface Hardware Configuration Below is a technical description of the Serial Interface Table 4 1 lists communication parameters Terminators are fixed to Carriage Return CR and Line Feed LF The connector used for the serial interface is a standard 6 wire RJ 11 telephone jack Lake Shore offers the Model 4001 10 foot Cable Assembly Model 4002 RJ 11 to DB 25 Adapter and the Model 4003 RJ 11 to DE 9 Adapter See Chapter 5 for Serial UO connector and adapter pin out details and Chapter 6 for adapter dimensional data Table 4 1 Serial Interface Specifications Transmission Three Wire Connector RJ 11 Modular Socket Timing Format Asynchronous RS 232C Electrical Format Transmission Mode Half Duplex Baud Rate 300 1200 or 9600 Bits per Character 1 Start 7 Data 1 Parity and 1 Stop Parity Type Odd Data Interface Levels Transmits and Receives Using EIA Voltage Levels Fixed Terminator CR ODH LF OAH 4 1 2 Serial Interface Settings To use the Serial Interface set the Baud rate Press Interface to display the screen to the right Press Interface again to cycle through the choices of 300 12
10. The relative function displays small variations in larger fields The Relative Set key captures or defines a relative setpoint which becomes the zero point of the relative reading and appears on the lower line of the display The relative reading appears in the top display with a A symbol The relative reading maintains the same resolution and units as the setpoint Accept new settings in two ways 1 Wait a few seconds until the built in timeout returns you to the normal display or 2 Press any key other than the function currently addressed For example after changing the range press any key other than Range Introduction 1 1 Lake Shore Model 420 Gaussmeter User s Manual Table 1 1 Model 420 Specifications Measurement Number of Inputs One Update Rate Three Per Second Autorange Yes Field Ranges Resolutions High Stability Probe High Sensitivity Probe Ultra High Sensitivity Probe Gauss ep Gauss tesla tesla Electronic DC Accuracy 0 45 of reading 0 05 of range Drift of DC Electronics 0 05 of reading 1 count per degree Celsius RMS Frequency Range 10 to 400 Hertz AC RMS Accuracy 5 or better Front Panel Display Type 2 line by 16 characters backlighted LCD Display Resolution 4 character see field ranges above Display Units Gauss or tesla Keypad Eight function Interfaces Corrected Analog Output 3 volt range Uncorrected Analog Output 3 volts for full scale range accuracy is probe
11. 1 Lake Shore Model 420 Gaussmeter User s Manual 3 1 2 Front Panel Display In normal operation the two row by sixteen character LCD provides magnetic readings on the top row and special information or readings on the bottom row Other information displays when using the various keypad functions Each character is comprised of a 5 by 7 dot matrix See Figure 3 2 Units kG G Probe Orientation m Relative DC Only a Current Reading UT RMS L Lower row used for Max Hold MAX shown above and Relative Setpoint SP readings Also used for various on off messages C 420 U 3 2 Figure 3 2 Front Panel Display Definition 3 2 MAX HOLD AND MAX RESET Max Hold displays the largest field magnitude measured since the last Max Reset Press Max Hold to view the maximum value in the lower line of the display and the field reading in the upper line Max Hold may also be used in conjunction with the Relative display see Paragraph 3 8 Max Reset clears the Max Hold value The Max Hold value also resets upon power up or when changing from AC or DC Max Hold functions differently with AC and DC fields In DC operation Max Hold captures the largest magnitude field reading This monitors slowly changing signals A field change not visible on the display can not be recorded in DC Max Hold The display shows only the magnitude of the maximum reading In AC RMS operation Max Hold captures the maximum RMS value 3 3 ZERO PROBE
12. C 40 to 100 C 40 to 100 C temperature range Mean temperature 0 08 C max 0 06 C max 0 06 C max 0 005 C max 0 04 C max coefficient of magnetic sensitivity Mean temperature 1 yV C max 1 yV C max 5 uV C max 0 4 uV C max 0 3 uV C coefficient of offset I nominal control current Mean temperature 0 18 C 0 15 C 0 15 C 0 15 C 0 18 C coefficient of approx approx approx approx approx resistance 34 AWG copper 34 AWG copper Not applicable 34 AWG copper 34 AWG copper with poly nylon with poly nylon with poly nylon with poly nylon insulation insulation insulation insulation Appendix A A 9 Lake Shore Model 420 Gaussmeter User s Manual B6 0 HALLCAL EXE PROGRAM The HALLCAL EXE program interfaces customer attached Hall generators to the Model 420 Gaussmeter See the Software License Agreement behind the title page of this manual Because of the many intricacies of proper calibration the Customer must accept responsibility for measurement accuracy Requirements Lake Shore Model 420 Gaussmeter connected via RS 232 to the computer s COM1 port Lake Shore Model MCBL 6 Cable Assembly IBM or compatible CPU Hall generator meeting the sensitivity ranges given below Hall generator calibration or sensitivity constant and serial number D D D D Set the Lake Shore Model 420 Gaussmeter to 300 Baud see Paragraph 3 11 Insert th
13. HGA 3030 amp HGCA 3010 Dimensions B 4 B 6 Transverse Hall Generator HGT 3010 HGT 3030 amp HGCT 3020 Dimensions cccccceeec es eeee sees B 4 B 7 Axial Hall Generator HGA 2010 DiIMeNnsiOns cccccececceeseseeeecececeaueseeceeeeeseaaeeeeeeeeeeaeeaeeeeseeseaaaeaaeess B 5 B 8 Transverse Hall Generator HGT 1010 DIMENSIONS cccccccccseeseeeeeeceeceeseececeeeseaueaeeeeeeaeeaeeeeeeeneeaeanes B 6 B 9 Transverse Hall Generator HGT 2010 DIMENSIONS ccccccccceeseseececeeaeeseeceeeeeseaueaeeeeeeeaeeaseeeeeseeaeaees B 6 B 10 Transverse Hall Generator HGT 2100 Dimensions cccccccceeseseeeecececeaeececececeaueaeeeeeeeaueaeeeeeeeseaaeaas B 6 LIST OF TABLES Table No Title Page 1 1 Model 420 Specifications iseia a edee eatea da iiae aeiee edia Eada diae eieiei ieia diadani 1 2 4 1 Serial Interface Specifications cccccccceccceeeeeenceceeeeeeeeeseaeeeceeeseesaaaeaeeeeeeaeaaeaeeeeseeeseecaeeeeeeeeeeeeanaeees 4 2 4 2 Sample BASIC Serial Interface Program 4 3 B 1 Cryogenic Hall Generator Specifications cccccecececeeecneceeeeeeeceecaeceeeeeseeeneaecaeeeeeeesecseaeeeeesesenensaeees B 4 B 2 Axial Hall Generator Specifications 2 0 2 2 eccccecceceeeeeeeeecee cece cece eeceaeaeeeeeeeeecseceaeaeeeeeseseecaeeeeeseeesieeeeeeeees B 5 B 3 Transverse Hall Generator Specifications 0 0 ee ceeeeeeeeeeenneeeeeeaeeeeeeneeeeesaeeeseeaaeeesnaeeeeesnaeeenenaeees B 7 Table of Contents
14. If the interface is DCE a Null Modem Adapter is required to exchange Transmit and Receive lines RJ11 RECEPTACLE Figure 5 8 Model 2003 RJ 11 to DE 9 Adapter Wiring Details Service 5 3 Lake Shore Model 420 Gaussmeter User s Manual 5 5 OPERATING SOFTWARE EPROM REPLACEMENT The operating software for the Model 420 is contained on one Erasable Programmable Read Only Memory EPROM Integrated Circuit IC The EPROM is numbered U36 and located just behind the microprocessor IC U31 The EPROM also has a label on top identifying the software version and date see Figure 5 9 Use the procedure below to replace the operating software EPROM WARNING To avoid potentially lethal shocks turn off the instrument and disconnect it from the AC power line before performing this procedure 1 Set power switch to Off and disconnect power cord from rear of unit 2 Use 5 64 hex key to remove four screws attaching top panel to unit 3 Use 5 64 hex key to loosen two screws attaching bottom panel to unit 4 Carefully remove back bezel 5 Slide top panel back and remove from unit 6 Locate software EPROM U36 on main circuit board Note its orientation circular notch on front of IC See Figure 5 9 7 Use IC puller to remove existing EPROM from socket 8 Use IC insertion tool to place new EPROM into socket noting its orientation 9 Replace top of enclosure and secure with four screws 10 Replace back bezel and use 5 64 hex key to ti
15. Lake Shore Model 420 Gaussmeter User s Manual This Page Intentionally Left Blank Table of Contents Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 1 INTRODUCTION 1 0 GENERAL Lake Shore Cryotronics Inc designed and manufactures the Model 420 in the United States of America It is highly accurate and ideally suited for field work It features e Field Measurement DC Accuracy 0 45 of Reading 0 05 of Range Auto Range DC or AC Field Measurement Individual Linearization of Hall Probes e Alphanumeric Display 4 character 1 Part In 3 000 Resolution On All Ranges 2 Line by 16 Character Backlighted Liquid Crystal Display e Other Operating Functions Gauss or Tesla Units Max Hold Relative Reading e Interface Serial Interface RS 232C Electrical Format Corrected and Monitor Analog Outputs e Probe Compatibility High Stability Probes HST 300 G to 300 kG Full Scale Ranges High Sensitivity Probes HSE 30 G to 30 kG Full Scale Ranges Ultra High Sensitivity Probes UHS 300 mG to 30 G Full Scale Ranges We welcome comments concerning this manual Although we make every effort to keep it error free some may occur When reporting a specific problem describe it briefly and include the appropriate paragraph figure table and page number Send comments to Lake Shore Cryotronics Attn Technical Publications 575 McCorkle Blvd Westerville
16. Max Reser 3 2 3 3 Zero Gre 3 2 3 4 Range EE 3 3 3 5 AG RL 3 3 3 6 EE RE 3 4 3 7 un Le 3 4 3 8 Relative begeestert at deers ee 3 4 3 9 Analog EE 3 4 3 10 Locking and Unlocking the kevpad 3 5 3 11 Factory Default SettingS sonr irar aa E E ATE 3 5 3 12 Probe Considerations ssssseessnnntensseeett ttrt tsttertttnntnsttrtrnnnnnsstntEnnnn nes ennEnn nenene ennn 3 5 3 12 1 Change PTODES iere Zug ebe ii ET A T E T A 3 5 3 12 2 Probe Handling EEN 3 5 3 12 3 Probe Operation 3 6 3 12 4 Probe Accuracy Considerations eeseeeeessseeeerneseerresisnnestennestinnestnnnesnnnnesttnneennnnet 3 6 d REMOTE OPERATION sie ccscceesccccceescvsecdeavestteenveccteed susucinescestcbenvestteentestceed KANAAN NENANA KERNAN KA ARANE RARR 4 1 4 0 eelere e Ee ee ae 4 1 4 1 Serial O IMtemtace n i i eiee aiii dee ng ieee adored de E iaa dan aaa aa raei 4 1 4 1 1 Serial Interface Hardware Configuraton nn 4 2 4 1 2 Serial Interface Settings ccccecceesceeeeeeeceeeeneeceeeensneeseenenedeneneeeeeeneeaeeseeneaeeenenenees 4 2 4 1 3 Sample BASIC Serial Interface Program 4 2 4 2 Serial Interface Command Summary c ccceeceeeeeeeeeeeeeeeeeeneeeeeenaeeeeeeaeeeseeneeeeeeaes 4 4 4 2 1 Command List Structure TEE 4 4 4 2 2 Interface Commande aero aiaaaikaaiana eaaiiE aiaia caa aaa aa iaaa EAE 4 4 4 2 3 Device Specific Commande 4 5 Table of Contents Lake Shore Model 420 Gaussmeter User s Manual TABLE OF CONTENTS Continued Chapt
17. Software EPDROM enant 5 4 6 1 Model 4001 RJ 11 Cable Assembly cece eeeeeeaecaeeeeeeeeeeeaeceeeeeseeaeaeeeeeeeeeeseecueaeeeeeeeeeeseeaeees 6 2 6 2 Model 4002 RJ 11 to DB 25 Adapter 0 0 0 2 ccececceceee cece ee eeceneaeeeeeeeseceaaaeeaeeeeeseseaaeaeeeeeeeseccueaeeeeeeeseeeesaeees 6 2 6 3 Model 4003 RJ 11 to DE 9 Adapter ccccccccscececeeseeeeecsnreececeaeeeceneeeeesaeeesccsaeeesseeeeeeeseaeeeeeeaeesseeeeenees 6 2 6 4 Model 2022 Rack Mo nt Kit eege EEN NEEN KENNEN NEEN NENNEN a 6 3 6 5 Model 4026 Dual Rack Mount helt 6 3 6 6 Model 4060 Standard Zero Gauss Chamber 6 4 6 7 Model 4065 Large Zero Gauss Chamber 6 4 6 8 Definition of Lake Shore Transverse Probes ccccseeccccccsesscececececeeseeeeceeeseseeseeeeeeeseaueaeeeeeseeseeauenaness 6 6 6 9 Definition of Lake Shore Axial Probes ccccccccccseeseeccceceseeseeeeeeeceaueseeeeeeeeseaueaseeeeeeaseaseceseeeseeseeaueaanees 6 7 6 10 Definition of Lake Shore Flexible Transverse Probes c cscecccececeeeeeeceeceseeaseceeeeeseaueaseeeseeseaneeaeees 6 8 6 11 Definition of Lake Shore Gamma bProbes 6 8 B 1 Flall Ge nerator THe Ory eege ae Ae he at i et Ab aot tel at re et ee B 1 B 2 Axial and Transverse Configurations ccececceece cece eeeeeaeceeeeeeeeeeeeeaaeceeeeeseseaaaeceeeeeeeeseceesaeeeseesensanaeees B 2 B 3 Typical Hall Generator HOOKUP issamen inae a Reeg KEEN deen B 3 B 4 Hall Generator Input Impedance B 3 B 5 Axial Hall Generator HGA 3010
18. There are two rear panel analog outputs on the Model 420 called the Corrected and Monitor Analog Outputs Both use BNC connectors with the center conductor carrying the signal and the outer portion the ground The Corrected Analog Output is a DC value proportional to the displayed field The displayed field reading may be corrected for probe nonlinearity and zero offset This output is not a real time signal but updates at the same rate as the display The Corrected output range is 3 volts eauals full scale for the selected range The example below shows the 3 kG range OkG Ge Soke 2 kG 1kG 1kG 2 kG 3 kG Output Voltage 3V 2V 1V 1V 2 V 3 V OV The Monitor Analog Output is a real time analog signal proportional to the magnetic field and scaled to 3 volts for full scale of selected range It is not as accurate as the Corrected Monitor Output but it has the full 400 Hz bandwidth of the AC measurement 3 4 Operation Lake Shore Model 420 Gaussmeter User s Manual 3 10 LOCKING AND UNLOCKING THE KEYPAD The Model 420 front panel keypad may be locked preventing unauthorized changes to the settings To lock the keypad press and hold Max Hold about 10 seconds until the display to the right appears To unlock the keypad press and hold Max Hold about 10 seconds until the display to the right appears The keypad unlocks and the display reverts to the normal display 3 11 FACTORY DEFAULT SETTINGS To return the i
19. User s Manual Consider gaussmeter probe and magnet tolerances before making critical measurements The accuracy of the gaussmeter reading is better than 0 1 of reading and 0 005 of range An absolute accuracy reading for gaussmeters and Hall probes is a difficult to specify because measurement variables are difficult to reproduce For example a 1 error in alignment to the magnetic field causes a 0 015 reading error The best probes have an accuracy of 0 1 This implies that the absolute accuracy measurement of a magnetic field can be no better than 0 15 under the best of circumstances and more likely 0 20 to 0 25 Operation 29 3 B 45 13 4 30 6 0 3 4 20 o 1 5 10 0 4 5 0 0 Error Deviation from Perpendicular 0 Effect of angular variations on percentage of reading error where Error 1 cos 0 100 Figure 3 5 Effect Of Angle On Measurements 3 7 Lake Shore Model 420 Gaussmeter User s Manual This Page Intentionally Left Blank Operation Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 4 REMOTE OPERATION 4 0 GENERAL This chapter covers the Serial Interface hardware and software Paragraph 4 1 and the interface command summary Paragraph 4 2 4 1 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 suppl
20. axial Instrumentation quality axial sensitivity low temperature coefficient phenolic package phenolic package 0 005 x 0 005 inch square 0 030 inch diameter circle 0 030 inch diameter circle 11 to 28 mV kG 0 56 to 1 04 mV kG 6 0 to 10 0 mV kG 1 RDG 20 to 20 kG 1 5 RDG 100 to 100 0 25 RDG 10 to 10 kG 1 00 RDG 30 to 30 kG 1 RDG 10 to 10 kG 2 RDG 20 to 20 kG kG 2 8 mV max 50 uV max 75 uV max 20 to 75 C 40 to 100 C 40 to 100 C 0 06 C max 1 uV C max 0 15 C approx 0 15 C approx 0 18 C approx 34 AWG copper with poly 34 AWG copper with poly 34 AWG copper with poly nylon insulation 0 005 C max 0 04 C max 0 4 uV C max 0 3 uV C max nylon insulation nylon insulation Lake Shore Model 420 Gaussmeter User s Manual r 0 50 in 0 125 in Eo of E Area 9 5 in min i WE Za 0 130 in max d 0 020 in Ge soso max over Hall plate i 1 0 028 in max over leads Figure B 8 Transverse Hall Generator HGT 1010 Dimensions 0 060 in max S rn 5 0 5 in Km 1 25 in Lead Length 0 175 in SS SE whe BH FS SE d lt 0 09 in Center of Active Area Figure B 9 Transverse Hall Generator HGT 2010 Dimensions 0 073 in 0 039 in 0 098 in E f em 0 030 in Wach ty Sea he Figure B 10 Transverse Hall Generat
21. dependent Serial communication with RS 232C electrical format 300 1200 or 9600 BAUD RJ 11 connector Instrument General Ambient Temperature Range 15 C to 35 C 59 F to 95 F Power Requirement 100 120 220 240 VAC 5 10 50 or 60 Hz 25 watts Size 216 mm wide x 90 mm high x 317 mm deep 8 54 x 3 5 x 12 5 inches half rack package Weight 3 kilograms 6 61 pounds 1 2 ELECTROSTATIC DISCHARGE Electrostatic Discharge ESD may damage electronic parts assemblies and equipment ESD is a transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field The low energy source that most commonly destroys Electrostatic Discharge Sensitive ESDS devices is the human body which generates and retains static electricity Simply walking across a carpet in low humidity may generate up to 35 000 volts of static electricity Current technology trends toward greater complexity increased packaging density and thinner dielectrics between active elements which results in electronic devices with even more ESD sensitivity Some electronic parts are more ESDS than others ESD levels of only a few hundred volts may damage electronic components such as semiconductors thick and thin film resistors and piezoelectric crystals during testing handling repair or assembly Discharge voltages below 4000 volts cannot be seen felt or heard 1 2 Introduction
22. length mounting panel and mounting ears to attach one Model 420 Gaussmeter to a 482 6 mm 19 inch rack mount space See Figure 6 4 EZE Dual Mounting Shelf for Two 1 2 Rack Gaussmeters Mounting panel and mounting ears to attach two Model 420 Gaussmeters to a 482 6 mm 19 inch rack mount space See Figure 6 5 4040 Handle Carrying Kit with Feet Contains side mounting handle and feet 4060 Standard Zero Gauss Chamber Calibrates standard probes Size 32 2 x 32 2 x 61 mm 1 27 x 1 27 x 2 4 in Bore 12 2 mm dia x 50 8 mm deep 0 48 x 2 in See Figure 6 6 Large Zero Gauss Chamber Calibrates Gamma probes Size 57 1 x 53 3 x 304 8 mm 2 25 x 2 06 x 12 in Bore 19 1 mm dia x 279 4 mm deep 0 75 x 11 in See Figure 6 7 4502 Model 420 Gaussmeter User s Manual Hall Generator Cable Assembly The MCBL 6 Cable Assembly connects a discrete Hall generator to the Model 420 Gaussmeter Cable is 2 meters 79 inches long The cable ships with the MCBL 6 HALLCAL EXE program on a 3 5 inch diskette which permits cable PROM programming through an IBM PC or compatible computer serial port Because of the many calibration intricacies the user is responsible for measurement accuracy See Appendix C Probe Extension Cables Contains a EEPROM for calibration data Probe and extension cable must be calibrated together Available part numbers and cables lengths are MPEC XXX MPEC 10 Probe Extension Cable 3 meters 10 feet MPEC 2
23. to set calibration We recommend the customer always check accuracy against a reference field rather than use the sensitivity value sent with the bare Hall generator Because Lake Shore has no control of conditions beyond the cable the customer must accept responsibility for accuracy and compatibility Finally Maganin wire is not usually acceptable for cryogenic installations because its resistance is often too high In cryogenic applications Hall generators normally connect with twisted pairs of copper wire such as 34 gauge Teflon insulated There are two reasons for this 1 The gaussmeter current source is normally limited in compliance voltage The Model 420 should not drive a load Hall generator Wires in cryostat and probe cable greater than 50 Q For best performance use a load less than 30 Q 2 Because the Model 420 input impedance is 420 Q there is a voltage drop due to lead resistance in series with the gaussmeter input The Lake Shore Hall generator sensitivity given on the data sheet includes no lead resistance See Figure B 4 The gaussmeter needs input sensitivity between 0 5 to 1 5 mV kG at its input Reable Host Hall Generator Open Circuit Sensitivity Model 450 i Gaussmeter Input Reable Host Sensitivity at Gaussmeter input is reduced by the lead input voltage divider Reable Lake Shore Model Rcust Customer MCBL 6 Cable Assembly Supplied Leads C 450 U C 4 Figure B 4 Hall Generator Input Impedance App
24. 0 dia 0 050 S a Stainless 42 to f 0 010 MCT 3160 WN Lon Steel 100 kG per C C 450 U 6 8 Figure 6 8 Definition of Lake Shore Transverse Probes 6 6 Accessories and Probes Lake Shore Model 420 Gaussmeter User s Manual Corrected Op Temp Coefficient Re Temp Maximum o Reading Range Zero Calibration MMA 0602 TH 2 0 125 MMA 0604 TH 4 0 125 MMA 0608 TH 8 0 125 0 020 dia of Io MMA 0618 TH 18 40 125 approx 0 010 C MMA 1302 UH 2 40 125 MMA 1304 UH 4 40 125 MMA 1308 UH 8 0 125 MNA 1902 VH 2 0 125 MNA 1904 VH 4 0 125 0 25 MNA 1908 VH 8 0 125 to s 0 015 C 30 kG MMA 2502 VH 2 0 063 MMA 2508 VH 8 0 125 MNA 1902 VG 2 0 125 MNA 1904 VG 4 0 125 Soe approx MNA 1908 VG 8 0 125 0 005 C MMA 2502 VG 2 0 063 MMA 2508 VG 8 0 125 MMA 2536 WL 36 0 25 0 010 C C 450 U 6 9 Figure 6 9 Definition of Lake Shore Axial Probes Accessories and Probes 6 7 Lake Shore Model 420 Gaussmeter User s Manual B 2 5 L A W L Z CC Zez Ee Cable Length 6 6 feet 0 35 0 030 dia 0 125 0 020 T This table is for L 3 inches and S 0 375 inch Corrected Operating Temperature Coefficient Model Active Stem Frequency Type Accuracy Temperature maximum
25. 00 or 9600 Baud To accept the new rate either wait about 6 seconds until the display disappears automatically or press any key other than Interface 4 1 3 Sample BASIC Serial Interface Program The program in Table 4 2 is a sample interactive serial poll routine for the Model 420 Serial Interface written in QuickBASIC V4 0 The following are typical examples using this BASIC program Input provided by the user is shown in bold type ENTER COMMAND FIELD Field Reading Query Unit returns field reading in the form XXX XX Decimal point placement appropriate to range 000 12 ENTER COMMAND RANGE Range Query Unit returns appropriate range 0 highest range through 3 lowest range 0 ENTER COMMAND UNITS Units Query Unit returns appropriate units G gauss T tesla G ENTER COMMAND ACDC AC or DC Query Unit returns appropriate setting 0 DC 1 AC 0 ENTER COMMAND 4 2 Remote Operation Lake Shore Model 420 Gaussmeter User s Manual 4 1 4 Notes On Using The Serial Interface To chain commands together insert a semi colon between them Multiple queries cannot be chained Queries generally use the same syntax as the associated setting command followed by a question mark They usually return the same information that is sent Add a query to the end of acommand string to confirm command execution For example UNIT G UNIT commands the Model 420 to set units to gauss then requests the Model 420 return the u
26. 5 Probe Extension Cable 7 6 meters 25 feet MPEC 50 Probe Extension Cable 15 2 meters 50 feet MPEC 100 Probe Extension Cable 30 5 meters 100 feet Accessories and Probes 6 1 o000 Lake Shore Model 420 Gaussmeter User s Manual ent N Cable Length 4 3 meters 14 feet C 450 U 6 1 Figure 6 1 Model 4001 RJ 11 Cable Assembly O iN payo at 2 wa e oooo0oo0o000000 o o o o o o o o o o o o at 1 69 inches 15 8 mm 0 63 inches C 450 U 6 2 Figure 6 2 Model 4002 RJ 11 to DB 25 Adapter 60 3 mm 2 37 inches St Figure 6 3 Model 4003 RJ 11 to DE 9 Adapter kK 15 9 mm 0 63 inches C 450 U 6 3 Accessories and Probes Lake Shore Model 420 Gaussmeter User s Manual NOTE Remove four Model 450 side screws with 5 64 2 mm hex key Drawing shows right side mounting Left side mounting also possible Item Description Rack Mount Ear 107 430 Rack Mount Support 107 431 Rack Mount Panel 107 432 Rack Mount Handle 107 433 Screw 6 32 x 1 2 Inch 0 035 FHMS Phillips Screw 8 32 x 3 8 Inch 0 081 FHMS Phillips C 450 U 6 4 Installation Procedure 1 Use 5 64 inch 2 mm hex key to remove two 6 32 x 1 4 black button head screws from side of Gaussmeter Place Gaussmeter on shelf Procedure ee Cy Use 5 64 inch 2 mm hex key to reinstall two 6 32 x 1 4 black button head screws through side of rack into corresponding holes in the si
27. AXC Initiate Max Clear Reset IDN Query Identification MAXR Max Reading Query RST Reset Instrument MULT Reading Units Multiplier Query BAUD Set Serial Interface Baud Rate RANGE Set Manual Range Status BAUD Serial Interface Baud Rate Query RANGE Manual Range Query Device Specific Commands REL Set Relative Mode Status 2 g ACDC Set AC DC Field Reading Status Ee Relative Mage Query ACDC AC DC Field Reading Query BE Relative Mode Reading Query AUTO Set Autorange Status On Off RELS Set Relative Mode Setpoint AUTO Autorange On Off Query REESI Relative Mode Setpoint Query FIELD Present Field Reading Query Se oe Ee GC Query LOCK Set Keypad Lock Status TODS YPE UCT EE LOCK Keypad Lock Query UNIT Set Gauss or Tesla Units MAX Set Max Hold Status UNIT Gauss or Tesla Units Query MAX Max Hold Query Be ZCAL Initiate Zero Probe Command 4 2 1 Command List Command Name Brief Description of Function Structure RANGE Manual Reading Query Input RANGE Syntax of what user must input Returned 0 1 2 or 3 Information returned in response Remarks l to the query Used to query the unit for manual range Range BE is dependent on type of probe installed There Explanation and definition o are four ranges possible for each probe where 0 returned data is the highest and 3 is the lowest range 4 2 2 Interface Commands IDN Query Identification Input IDN Returned lt manufacturer gt lt model number gt lt serial number gt lt
28. For details on available accessories and probes see Chapter 6 Operation 3 5 Lake Shore Model 420 Gaussmeter User s Manual Do not bend from tip of probe N S Stem Flexible Transverse Probe Maximum Bend Angle Figure 3 3 Maximum Flexible Probe Bend Radius 3 12 3 Probe Operation NOTE For best results allow the instrument and probe to warm up Tre Lake Shore Logo for at least 5 minutes before zeroing the probe and at least 30 minutes for rated accuracy The probe and the zero gauss chamber should be at the same temperature a itt In the DC mode of operation probe orientation affects the polarity reading of the gaussmeter On a transverse probe the Lake Shore Transversa Probe Onentation name printed on the handle indicates the side for positive flux For Positive Measurement entry On an axial probe positive flux entry is always from the front of the probe See Figure 3 4 If the magnetic field orientation is unknown determine it by turning ee on Max Hold and slowly adjusting the probe As the probe turns and the measured field rises and falls its maximum value is held Axial Probe Orientation on the display Note probe orientation at the maximum reading to For Positive Measurement identify the field orientation Figure 3 4 Probe Orientation 3 12 4 Probe Accuracy Considerations for Positive Measurement NOTE For best results allow the instrument and probe to warm up for at least 5 minutes befor
29. NITIONS PROBE INPUT PIN DESCRIPTION Input NC NC ITEMP ITEMP VIEW FROM MATING SIDE OF CONNECTOR 1 2 3 4 5 6 7 8 DA 15 Connector 9 C 450 U 5 2 EE DATA Figure 5 2 DA 15 PROBE INPUT Connector Details CR ANALOG OUTPUTS Corrected Monitor PIN DESCRIPTION 1 Analog Output Center Conductor 2 Ground Connector Shell C 450 U 5 3 Figure 5 3 Corrected and Monitor ANALOG OUTPUTS Connector Details SERIAL UO Serial In RxD Serial In RxD 1 2 Serial Ground Serial Ground Serial Out TxD Serial Out TxD RJ 11 Receptacle C 450 U 5 4 Figure 5 4 SERIAL I O RJ 11 Connector Details 5 2 Service Lake Shore Model 420 Gaussmeter User s Manual 5 4 SERIAL INTERFACE CABLE AND ADAPTERS To aid in Serial Interface troubleshooting Figures 5 6 through 5 8 show wiring information for the cable assembly and the two mating adapters amp a DI TxD YELLOW N lt Gnd GREEN DI e Gnd RED A N RxD BLACK a Ze D Figure 5 6 Model 2001 RJ 11 Cable Assembly Wiring Details CONNECTOR NOT USED For Customer supplied 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 RECEPTACLE DB9 CONNECTOR NOT USED For Customer supplied computer with DE 9 Serial Interface Connector configured as DTE
30. Ohio 43082 8888 This manual is subject to change without notice 1 1 MODEL 420 GAUSSMETER SYSTEM DESCRIPTION The Model 420 has an easy to use front panel that includes an alphanumeric Liquid Crystal Display LCD for message based front panel operation Perform and monitor most operations through the front panel keypad and message display The display has a resolution of 4 characters The Model 420 measures fields from 3 mG 0 3 UT to 300 kG 30 T in either gauss or tesla Set field ranges either manually or with auto ranging The Range key displays the full scale value and cycles through allowable ranges for the probe installed The Auto Range function automatically selects the range with the best resolution for the measured field The gaussmeter measures both DC and AC field values In DC operation it displays the field at the probe with the sign orientation followed by appropriate field units In AC operation it displays a RMS value for the field at the probe The DC and AC values are available over the Serial I O Computer Interfaces and also the Corrected Analog Output The Monitor Analog Output displays actual magnetic field waveform The Max Hold function captures and displays the largest field magnitude since the last Max Reset After pressing Max Hold the maximum value appears in the lower display while the upper display contains the live field reading In AC RMS the Max Hold feature displays the maximum RMS value of the waveform
31. User s Manual Model 420 Gaussmeter El akeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA Internet Addresses sales lakeshore com service 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 0 21 August 1997 Lake Shore Model 420 Gaussmeter User s Manual LIMITED WARRANTY Lake Shore Cryotronics Inc henceforth Lake Shore the manufacturer warrants this product to be free from defects in material or workmanship for a period of twelve 12 months from the date of shipment During the warranty period under authorized return of instruments or component parts to Lake Shore freight prepaid the company will repair or at its option replace any
32. and a DA 15 Probe Input Connector See Chapter 5 for rear panel connector pin out details Power and Fuse Assembly The power and fuse assembly is the primary entry and control point for AC power to the unit The assembly consists of three parts power line jack power on off switch and the fuse drawer The line cord connects to the power line jack The on off switch controls power to the unit The I symbol shows when power is on and the O shows when power is off The fuse drawer has a dual purpose housing the fuse and setting unit input power Serial UO Connector The Serial I O Input Output Connector accepts the standard RJ 11 telephone connector Lake Shore offers RJ 11 to DE 9 or DB25 Adapters that permit connection to a computer See Paragraph 4 1 and 5 4 Corrected and Monitor Analog Outputs Analog outputs are available on two Bayonet Nut Connectors BNCs The signal is on the center conductor while the outer casing is for ground Both outputs may be used simultaneously The corrected output is not a real time signal but updates at the same rate as the display The default range of the corrected output is 3 volts equals full scale for the range The monitor output is a live analog signal proportional to the magnetic flux density waveform See Paragraph 3 12 for further operational information Probe Input Connector The probe plugs into the DA 15 connector Always turn off the instrument before connecting the probe Align t
33. angle of the tip in relation to the magnetic field The greater the angle the higher the percentage of error For example a 5 angle causes a 0 4 error a 10 angle induces a 1 5 error etc See Paragraph 3 15 Carefully place probe in contact with the magnet and hunt a bit for the maximum reading For this example we used a 999 1 Gauss probe reference magnet The top line displays the current reading The bottom line displays the maximum reading captured which is within the tolerance of our reference magnet The top line continually changes as the probe moves but the bottom remains fixed on the highest reading To capture a new maximum value press Max Reset After successfully completing this checkout procedure the unit is ready for normal operation Installation 2 3 Lake Shore Model 420 Gaussmeter User s Manual This Page Intentionally Left Blank Installation Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 3 OPERATION 3 0 GENERAL This chapter covers aspects of Model 420 operation Front Panel Controls Paragraph 3 1 Front Panel Functions Paragraphs 3 2 thru 3 10 Default Settings Paragraph 3 11 and Probe Handling Considerations Paragraph 3 12 See Chapter 4 for remote serial interface operation 3 1 DEFINITION OF FRONT PANEL CONTROLS The front panel consists of two major sections 8 front panel keys Paragraph 3 1 1 and a 2 row by 16 character Liquid Crystal Display LCD Paragraph 3 1 2
34. ases of instrument operation service and repair Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended instrument use Lake Shore Cryotronics Inc assumes no liability for Customer failure to comply with these requirements The Model 420 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instrument Environmental conditions outside of the conditions below may pose a hazard to the operator and surrounding area e Temperature 5 to 40 C e Maximum relative humidity 80 for temperature up to 31 C decreasing linearly to 50 at 40 C e Power supply voltage fluctuations not to exceed 10 of the nominal voltage Introduction 1 3 Lake Shore Model 420 Gaussmeter User s Manual Ground The Instrument To minimize shock hazard connect the instrument chassis and cabinet an electrical ground The instrument is equipped with a three conductor AC power cable Plug the power cable into an approved three contact electrical outlet or use a three contact adapter with the grounding wire green firmly connected to an electrical ground safety ground at the power outlet The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Do Not Operate In An Explosive Atmosph
35. available over the Serial Interface and both Analog Outputs In AC operation the RMS readings meet specified accuracy from 10 to 400 Hz The AC RMS reading is defined as the square root of the average of the square of the field function taken through one period The AC value is available over the Serial Interface The Corrected Analog Output yields a DC voltage representation of the Peak or RMS reading while the Monitor Analog Output yields a true analog waveform In fact the Monitor Analog Output is not affected by the selection of AC or DC When changing to AC or DC the unit maintains previously established Relative and Alarm setpoints but Max Hold operation changes see Paragraph 3 2 Operation 3 3 Lake Shore Model 420 Gaussmeter User s Manual 3 6 GAUSS TESLA The Model 420 displays magnetic field values in gauss G or tesla T Press Gauss Tesla to toggle the display between the two units The relation between gauss and tesla is 1 G 0 0001 T or 1 T 10 000 G When field units are changed relative and alarm setpoints convert to the new units with no interruption in operation The Corrected and Monitor Analog Outputs are not affected by a change in units When tesla is selected the Model 420 displays AC or DC field values followed by T for tesla mT for millitesla or uT for microtesla and formats field values over the Serial Interface accordingly When gauss is selected the Model 420 displays AC or DC field values fol
36. de of the Gaussmeter C 450 U 6 5 Figure 6 5 Model 4026 Dual Rack Mount Shelf Accessories and Probes 6 3 Lake Shore Model 420 Gaussmeter User s Manual NOTE Periodically de magnetize degauss the chamber Using a magnetized chamber to zero a probe can lead to erroneous field readings If no professional degausser is available use a bulk tape degausser Radio Shack P N 44 232 or equivalent Front View Side View a 12 2 mm 0 48 in diameter by 50 8 mm 2 in deep bore 1266 in ars Jae za Dm gt a 61 mm 2 4 in _ gt 1 266 in C 450 U 6 6 Figure 6 6 Model 4060 Standard Zero Gauss Chamber Front View 19 mm 0 75 in diameter opening 57 2 mm 2 25 in 31 8 mm 1 25 in oar 4mm 2 06 in 304 8 mm 12 in Depth of Opening 279 4 mm 11 in Side View C 450 U 6 7 Figure 6 7 Model 4065 Large Zero Gauss Chamber 6 4 Accessories and Probes Lake Shore Model 420 Gaussmeter User s Manual 6 2 PROBES There are four types of Model 420 probes available Transverse Figure 6 8 Axial Figure 6 9 Flexible Transverse Figure 6 10 and Gamma Figure 6 11 each named by its Hall sensor orientation Because the Model 420 covers such a wide magnetic field range 0 01 mG to 300 kG three probe ranges are available High Stability HST High Sensitivity HSE and Ultra High Sensitivity UHS Consult the factory for availability of probe types not detailed in these figures Selecting the
37. density Ww erg cm 10 Jim energy product Demagnetization factor dimensionless NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 47M b Multiply a number in Gaussian units by C to convert it to SI e g 1 Gx 10 T G 10 T c Sl 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 the definition B Uo H M where to uo 4r x 107 H m The lower one is not recognized under SI and is based on the definition B UoH J where the symbol is often used in place of J d 1 gauss 10 gamma y e Both oersted and gauss are expressed as cm eg ss in terms of base units f A m was often expressed as ampere turn per meter when used for magnetic field strength g Magnetic moment per unit volume h The designation emu is not a unit i Recognized under SI even though based on the definition B ua J See footnote c j Ur W Uo 1 x all in SI p is equal to Gaussian y k B Hand pM H have SI units J m M H and B H 4 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
38. e 5 25 inch disk and type the default drive A or B Type HALLCAL to execute the HALLCAL EXE program The program prompts for the Probe serial number Type any combination of 6 letters or numbers Press Enter when done kh OO N 5 The program prompts for the probe type Enter 0 for Hall generators with sensitivities between 5 6 and 10 4 mV kG 100 mA current Enter 1 for Hall generators with sensitivities between 0 56 and 1 04 mV kG 100 mA current 6 The program prompts for the Calibration Constant Enter the magnetic sensitivity in mV kG at a control current of 100 mA Remember to account for the Gaussmeter 420 input impedance when calculating the proper load resistor to install 7 The program displays all values entered along with designated F keys F1 Probe Serial Number ABC123 F10 Program Probe F2 Probe Type 0 Esc Exit Program F3 Calibration Constant X XXX To change any parameter press the appropriate F key and type in the new value When everything appears correct press F10 to program the probe 8 It takes about 20 seconds to program the probe After the probe is programmed press Esc to exit the program A 10 Appendix A
39. e ere LEE B6 0 HAEL CAL EXE Err eebe eebe ed artic tie etl Set eae ii D D Q dn Lol Lt s DOD O GAT a gt Table of Contents Lake Shore Model 420 Gaussmeter User s Manual LIST OF ILLUSTRATIONS Figure No Title Page 2 1 Model 420 Rear Panel 2 2 3 1 Model 420 Front TEE 3 1 3 2 Front Panel Display Definition 2 02 22 cce cscc teesceceueescuetes eedi iei aidia idite ainidi 3 2 3 3 Maximum Flexible Probe Bend Radius cccccccccssessececeeecesesceeeceeeseeaseeeceeeseseeaeeeeeeeseaueesseeeseeseeauensnees 3 6 3 4 Probe Orientation For Positive Measurement esssnsnnuesssrrnnrnesssnnrnriurssrnrrresnnnnrnrrssssnnrnrrresnrrrrreresnn 3 6 3 5 Effect Of Angle On Measurements anst tnnt nnnn nten ttns nn tnnn nnen 3 7 4 1 Seral Mtera ce A dA P S eege ee ENEE Ee 4 1 5 1 Power Fuse ACCESS csseececececaseesececececeauesseeceeeeseauesseceaseaueaseeeeeeeseaueasneeeeeeseaueneceesseaueasneaseeessesseauenseees 5 1 5 2 DA 15 PROBE INPUT Connector Details 5 2 5 3 Corrected and Monitor ANALOG OUTPUTS Connector Details 5 2 5 4 SERIAL I O RJ 11 Connector Details 5 2 5 5 Model 4001 RJ 11 Cable Assembly Wiring Details cccccceecceceeceeceeeeeeeeeeeaeeeeeeeeeesecsaeaeeeeeeeeeetenaeees 5 3 5 6 Model 4002 RJ 11 to DB 25 Adapter Wiring Details 5 3 5 7 Model 4003 RJ 11 to DE 9 Adapter Wiring Details 0 ieee eeeeceeeenneeeeeeeaeeeseneeeeesaeeeseenaeeeeneeeenenea 5 3 5 8 Location Of Operating
40. e positive with respect to the other This edge charging sets up an electric field which exerts a force on the moving electrons equal and opposite to that caused by the magnetic field related Lorentz force The voltage potential across the width of the conductor is called the Hall voltage This Hall voltage can be utilized by attaching two electrical contacts to the sides of the conductor The Hall voltage can be given by the expression Mu Yg B sin 0 where V Hall voltage mV Yg Magnetic sensitivity mV kG at a fixed current B Magnetic field flux density kilogauss 6 Angle between magnetic flux vector and the plane of Hall generator The Hall voltage varies with the angle of the sensed magnetic field reaching a maximum with the field perpendicular to the plane of the Hall generator B2 1 ACTIVE AREA T a The Hall generator assembly contains the 4 sheet of semiconductor material normally ae called a Hall plate to which the four Z E d contacts are made In its simplest form the 8 gt F Hall plate is a rectangle of fixed length width and thickness Due to the shorting effect of the current supply contacts most F e V B magnetic field sensitivity is contained in an force on electron area approximated by a circle centered in the Hall plate with a diameter equal to the VH VH plate width Thus when the active area is Blue Clear or Yellow given the circle as described above is the common e
41. e zeroing the probe and at least 30 minutes for rated accuracy The probe and the zero gauss chamber should be at the same temperature Several element impact probe accuracy Zero the probe before making critical measurements The zero probe function cancels out the zero offset of the probe or small magnetic fields It is normally used with the zero gauss chamber but may be used with a non shielded probe registering the local earth magnetic field To cancel out large magnetic fields use the Relative function see Paragraph 3 8 Probe temperature can also affect readings Read the probe specification sheets to determine possible temperature effects To help offset the effects of temperature on the Hall sensor a thermistor may be included in the Lake Shore High Sensitivity and Ultra High Sensitivity Probes The High Stability Probe requires no temperature correction due to inherent thermal stability of materials used in its construction Probe readings depend on the angle of the sensor Hall sensor in relation to the magnetic field Maximum output occurs when the flux vector is perpendicular to the plane of the sensor This is the condition that exists during factory calibration The greater the deviation from right angles in either of three axes the larger the reading error For example a 5 variance on any one axis causes a 0 4 error a 10 variance induces a 1 5 error etc See Figure 3 5 3 6 Operation Lake Shore Model 420 Gaussmeter
42. endix A A 5 Lake Shore Model 420 Gaussmeter User s Manual B5 0 SPECIFICATIONS This section covers three types of Hall generators available from Lake Shore HGCA amp HGCT Series Cryogenic Hall generators Figures B 5 and B 6 with specifications Table B 1 HGA Series Axial Hall generators Figures B 5 and B 7 with specifications Table B 2 and HGT Series Transverse Hall generators Figures B 8 thru B 10 with specifications Table B 3 0 25 in 9 5 in gt diameter 0 20 in min gi S Se gt D8 OOOO B 0 20 in 0 105 ord D diameter Figure B 5 Axial Hall Generator HGA 3010 HGA 3030 and HGCA 3010 Dimensions SSC 9 5 in min KH A 0 180 in w Lead Length 0 240 in SOOO max lt lt yF d gt le Center of 0 043 in max Protective Active Area Ceramic Case Figure B 6 Transverse Hall Generator HGT 3010 HGT 3030 and HGCT 3020 Dimensions Table B 1 Cryogenic Hall Generator Specifications Cryogenic HGCT 3020 Description Cryogenic transverse ceramic package Active area 0 040 inch diameter circle Output resistance 1 ohm Nominal control current Icn 100 mA Maximum continuous current 300 mA non heat sinked Magnetic sensitivity lc nominal control 0 56 to 1 04 mV kG 0 56 to 1 04 mV kG current Maximum linearity error 1 0 RDG 30 to 30 kG 1 0 RDG 30 to 30 kG sensitivity vs field 2 0 RDG 150 to 150 kG 2 0 RDG 150 to 150 kG Zero field offset voltage Ic nomi
43. eproduced 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 420 Gaussmeter User s Manual TABLE OF CONTENTS Chapter Paragraph Title Page 1 INTRODUCTION wisi cccecicectetetenttetececccctecs ec EES AAA ENKAN KENA NE AAAA A ENKAN NENAS KERANA ENNAN AANE 1 1 1 0 Gen ral el irei aieeaa N aa r dae aal raa a ud a a ded Ee 1 1 1 1 Model 420 Gaussmeter System Description 1 2 1 2 Electrostatic Discharge inesi aein ee i i ia e a RER 1 4 1 2 1 Identification of Electrostatic Discharge Sensitive Components 1 4 1 2 2 Handling of Electrostatic Discharge Sensitive Components 1 5 1 3 Safety SUMMA aieiai asii eda i ii a a aii iaid eaa aada 1 5 1 3 Safety Symbols iiis iinn ederi ENEE ed i aii ee nee en iaeia 1 6 KN INSTALLATION ME 2 1 2 0 ET 2 1 2 1 Inspection and Uppa KiM EE 2 1 2 2 Repackaging For Shipment ccc ccceesseceeeeeeeeeeeeeeneeeeeneeeeseeeneeseeneeeeeeeseeaeseeeneeeees 2 1 2 3 Definition of Rear Panel Connections s sssessseserenssrettnrtensttttttnntenrertrrrnnnnnesree nte 2 2 2 4 Initial Setup and System Checkout Procedure 2 3 3 OPERATION EE 3 1 3 0 EE 3 1 3 1 Definitions of Front Panel Controls reenn 3 1 3 1 1 Front Panel Keypads siiccsensetcecinieseti atthe naiecsee EE EEN 3 1 3 1 2 Front Panel Display ic e dscerenseceseciedc ge Ee EEN ead 3 2 3 2 Max Hold and
44. er Paragraph Title A SERV CE ees ee cece seen ch cc aenea Aaii aa tice dest ded eevee a aaa aa daai aa 5 0 General st et eebe bein neal in hee ated 5 1 General Troubleshooting eccccceeeeeeeeeeeeeeeeeeeeeeseecaeeeseenaeeeeeeneeeeeaes 5 2 Changing Power Setting and Fuse Rating 5 3 Rear Panel Connector Definitions ccccceeeeeeeeeeeceeeeeeeteeseneeeeeeeees 5 4 Serial Interface Cable and Adapters sssssenenseeseernrtnnseesrtrnrrnnsererene 5 5 Operating Software EPROM Replacement sssssessenerensseeernrrenssererenen 6 ACCESSORIES AND PROBES w cccccsceseeeceeeeeeeeeeenee eee eeeeeeaeeeeeeeeeseseeeaneeseeeeeeeeees 6 0 General deed eegen tere Nace anit ee aca tata Eege 6 1 ACCESSONES EE 6 2 Probe Selection Criteria te nrresretnntnnrtertrnnnnnentennn nanen APPENDIX A UNITS FOR MAGNETIC PROPERTIES ccseeseeeeeeeeeeeesseeneeeeeeees APPENDIX B HALL GENERATOR cccceeeeeceeeceeeeeseeeeeeeeesesseeaeeeseeeeeseeseeaneeeeeeees B1 0 nger EE andere il in E een B2 0 Theor OF Operaio er e E vagy subd EES B2 1 Active EE B2 2 OnlentatiOn EE B2 3 ie Late Lie BEE B2 4 Elan e ee ea a r ENEE Agen B2 5 Lead Configurations cccccccieccedectecesdectensedecenensedeceneedeeteneedeneeneceeteneecs B3 0 Hall Generator Generic Hookup ceceeeecceceeeeeeeeeeeeeeeeeeeeteseenaeeeeeeees B4 0 Using a Hall Generator with the Model 420 ecceeceeeeeeeeeetteeeeeeneeees B5 0 e
45. eration may continue If the unit powers up with no probe attached the message to the right displays 3 12 2 Probe Handling CAUTION Take care when handling the probe the tip is very fragile Stressing the Hall sensor can alter its calibration Any excess force can easily break the sensor Broken sensors are irrepairable Although probes are designed as sturdily as possible they are still fragile This is especially true for the exposed ceramic tip of transverse probes Take care to place no pressure on the ceramic tip during measurements Secure the probe in place only at the handle Never apply force to the probe stem Any strain on the ceramic substrate may alter the probe calibration and excessive force may destroy the Hall sensor Avoid repeated flexing of the sensor mounted at the end of a flexible stem As a rule do not bend the stem more than 45 from the base see Figure 3 3 Never apply force to the tip of the probe On all probes do not pinch or allow cables to be struck by heavy or sharp objects Although Lake Shore repairs damaged or severed cables that are returned probes are not always repairable When probes are installed on the gaussmeter but not in use place the protective tube provided with many probes over the probe handle and stem to protect the tip When the gaussmeter is not in use store probes separately in some type of rigid container preferably the cardboard and foam container in which Lake Shore probes ship
46. ere Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away From Live Circuits Operating personnel must not remove instrument covers Refer component replacement and internal adjustments to qualified maintenance personnel Do not replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them Do Not Substitute Parts Or Modify Instrument Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to an authorized Lake Shore Cryotronics Inc representative for service and repair to ensure that safety features are maintained 1 4 SAFETY SYMBOLS Direct current power line Equipment protected throughout by double insulation or reinforced insulation equivalent to Class II of IEC 536 see Annex H Caution High voltages danger of electric shock Background color Yellow Symbol and outline Black Alternating current power line Alternating or direct current power line Three phase alternating current power line Earth ground terminal Caution or Warning See instrument documentation Background color Yellow Symbol and outline Black Protective conductor terminal gt E p Frame or chassis terminal On supply Off supply f Fuse O Or ede
47. eter display appears similar to the one to the right NOTE For best results warm up instrument and probe for at least 5 minutes before zeroing probe and at least 30 minutes for rated accuracy The probe and the zero gauss chamber should be at the same temperature Some Lake Shore probes come with a clear plastic sleeve to protect the probe tip when not in use The sleeve slides up and down the probe cable To place the probe in the zero gauss chamber slide the protective sleeve back exposing the probe tip before placing the tip in the chamber Place the probe in the zero gauss chamber and press the front panel Zero Probe key The display to the right appears Press Zero Probe again The CALIBRATING message briefly displays followed by the normal display Do not move the probe while the CALIBRATING message displays NOTE If the unit performs well to this point the unit is functioning properly If there is a reference magnet available continue the test using the magnet to verify the Model 420 accuracy If continuing the procedure with a reference magnet verify the probe accommodates the magnet range Use the Range Select key to select the proper range or press Auto Range Set the display for DC Finally since probe orientation is very selective press Max Hold to capture the highest reading CAUTION Take care when handling the probe its tip is very fragile Excess force may break it NOTE Probe readings depend on the
48. fications 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 TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distinguish their products as trademarks Where those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or symbol ASYST is a trademark of MacMillian Software Co Duco is a trademark of E l DuPont de Nemours Hercules is a trademark of Hercules Inc MS DOS is a trademark of MicroSoft Corporation NI 488 2 is a trademark of National Instruments PC XT AT and PS 2 are trademarks of IBM Scotch is a trademark of 3M TACKIWAX is a trademark of CSC Scientific Co Inc Apiezon is a trademark of Biddle Instruments Formvar is a trademark of Monsanto Chemical Company IDEAS is a trademark of Unisys Corporation and is licensed for use with Lake Shore software drivers CalCurve Carbon Glass Cernox Duo Twist Quad Lead Quad Twist and SoftCal are trademarks of Lake Shore Cryotronics Inc Stycast is a trademark of Emerson amp Cuming Teflon is a trademark of DuPont De Nemours Copyright 1993 1997 by Lake Shore Cryotronics Inc All rights reserved No portion of this manual may be r
49. firmware date gt Format LSCI MODEL340 aaaaaa nnnnnn term Remarks Identifies the instrument model and software level RST Reset Instrument Input RST Returned Nothing Remarks Sets controller parameters to power up settings BAUD Set Serial Interface Baud Rate Input BAUD 0 BAUD 1 Or BAUD 2 type The 3 settings are 0 300 Baud 1 1200 Baud 2 9600 Baud Returned Nothing Remarks Sets the Serial Interface Baud rate BAUD Serial Interface Baud Rate Query Input BAUD Returned Returns current Serial Baud rate where 0 300 Baud 1 1200 Baud and 2 9600 Baud Remote Operation 4 5 4 2 3 ACDC Input Returned Remarks ACDC Input Returned Remarks AUTO Input Returned Remarks AUTO Input Returned Remarks FIELD Input Returned Remarks LOCK Input Returned Remarks LOCK Input Returned Remarks MAX Input Returned Remarks MAX Input Returned Remarks 4 6 Lake Shore Model 420 Gaussmeter User s Manual Device Specific Commands Set AC or DC Magnetic Field Reading Status ACDC Ooracpc 1 Nothing Configures the unit for AC or DC measurements 0 DC 1 AC AC or DC Magnetic Field Reading Query ACDC Oorl Queries current AC or DC measurement status 0 DC 1 AC Set Auto Range Status AUTO 0 or AUTO 1 Nothing Sets the Auto Range status 0 Auto Range Off 1 Auto Range On Auto Range Query AUTO o
50. g guideline 2 above Lake Shore gaussmeter probes provide valid readings over different ranges of magnetic fields Check the specification sheet for these usable ranges Use High Stability probes i e VG models on 300 gauss 30 millitesla to 30 kilogauss 3 tesla full scale ranges Use High Sensitivity probes e VH models on 30 G 3 mT to 30 kG 3 T full scale ranges Use specially calibrated High Field probes for fields above 30 kG 3 T Use the Gamma probe on the 300 mG 30 uT and 3 G 300 UT ranges If no standard probe configuration fits your needs Lake Shore offers custom probes to meet physical temperature and accuracy requirements Contact Lake Shore for details Accessories and Probes 6 5 Lake Shore Model 420 Gaussmeter User s Manual Probe Table Definitions Usable Full Scale Ranges vs Probe Type A Distance from tip of probe to centerline of active area E SE EES Usable on Weer E is Ranges i 300kG 30kG UHS Ultra High Sensitivity Probe Cable length 6 6 feet 0 35 0 030 dia T Es i Corrected Op Temperature fee Active Stem Fred T A Temp Coefficient Max Number L T A Area Material Range YP Qccuracy p E ler me of rdg Range Zero Calibration 2 MMT 6J02 VH MMT 6J04 VH MMT 6J08 VH MMT 6J18 VH eee MNT 4E02 VH MNT 4E04 VH MMT 6J02 VG MMT 6J04 VG MMT 6J08 VG MMT 6J18 VG MNT 4E02 VG MNT 4E04 VG 0 150 0 04
51. ghten two screws attaching bottom panel to unit 11 Reconnect power cord to rear of unit and set power switch to On 12 Perform the initial setup and system checkout see Paragraph 2 6 When replacing the operating software EPROM all operating parameters reset to factory defaults specified in Paragraph 3 14 Front Rear Power Inlet C 450 U 5 9 Figure 5 9 Location Of Operating Software EPROM 5 4 Service Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 6 ACCESSORIES AND PROBES 6 0 GENERAL This chapter lists Model 420 Gaussmeter Accessories Paragraph 6 1 and Probes Paragraph 6 2 6 1 ACCESSORIES Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit MODEL NUMBER DESCRIPTION 4001 RJ 11 Cable Assembly Four Wire Cable Assembly with RJ 11 plugs on each end Used with RS 232C Interface Cable is 4 3 meters 14 feet long See Figure 6 1 RJ 11 to DB 25 Adapter Adapts RJ 11 receptacle to female DB 25 connector Connects Model 420 to RS 232C Serial Port on rear of Customer s computer See Figure 6 2 ap RJ 11 to DE 9 Adapter Adapts RJ 11 receptacle to female DE 9 connector Connects Model 420 to RS 232C Serial Port on rear of Customer s computer See Figure 6 3 IEEE 488 Interface Cable Connects Model 420 to customer supplied computer with IEEE 488 4004 8 Interface Cable is 1 meter 3 3 feet long Half Rack Mounting Kit for One 1 2 Rack Gaussmeter Half
52. he positive terminal of the current supply and the magnetic field direction is as shown in Figure B 2 a positive Hall voltage generates at the blue lead V Reversing either the current or the magnetic field reverses the output voltage B2 5 LEAD CONFIGURATIONS All Hall generators except Models HGCA 3020 and HGCT 3020 have 34 AWG solid copper with poly nylon insulation and have the lead configuration below Red IC Green IC Input Control Current Blue VH Clear VH Output Hall Voltage The Model HGCA 3020 and HGCT 3020 Hall generators have 34 AWG stranded copper with Teflon insulation and have the lead configuration below Red IC Black IC Input Control Current Blue VH Yellow VH Output Hall Voltage B3 0 HALL GENERATOR GENERIC HOOKUP The Hall voltage leads may connect directly to a readout instrument such as a high impedance voltmeter or to electronic circuitry for amplification or conditioning Device signal levels are in the range of microvolts to hundreds of millivolts In this case a separate precision current source Lake Shore Model 120CS or equivalent is necessary See Figure B 3 CAUTION e The four Hall generator leads connect to four points on a semiconductor sheet with different potentials No two leads can connect together without adversely affecting operation The current source and the output indicator cannot connect but must be isolated from each other One or the other but not b
53. he probe connector with the rear panel connector and push straight in to avoid bent pins For best results secure the connector to the rear panel using the two thumbscrews A tight connector keeps the cable secure and prevents interference See Paragraph 3 12 for additional probe considerations 2 2 Installation 2 4 Lake Shore Model 420 Gaussmeter User s Manual INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE This procedure verifies basic unit operation before initial use for measurements 10 11 12 CAUTION Check power source for proper voltage before connecting line cord Check power setting on fuse drawer window Damage may occur if connected to improper voltage Check power source for proper voltage The Model 420 operates with 100 120 220 or 240 5 10 AC input voltage Check fuse drawer window for proper voltage setting If incorrect see Paragraph 5 2 Ensure power switch is off O CAUTION The probe must be connected to the rear of the unit before applying power to the gaussmeter Damage to the probe may occur if connected with power on Plug in the DA 15 probe connector to PROBE INPUT Use thumbscrews to tighten connector to unit Connect and check all other rear panel connections SERIAL I O or ANALOG OUTPUTS before applying power to the unit Plug line cord into receptacle Turn power switch on I The front panel display turns on and briefly displays the message to the right The normal gaussm
54. ied computer must have a Serial Interface port The Model 420 Serial Interface complies with the electrical format of the RS 232C Interface Standard A Serial Interface between the computer and the Model 420 permits remote monitoring and control of Model 420 control functions which in turn controls Model 420 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 1 1 for Serial Interface hardware configuration and adapters Paragraph 4 1 2 for Serial Interface settings and Paragraph 4 1 3 fora sample BASIC program to establish communications between the computer and the Model 420 LSCI Model 4002 RJ 11 to DB 25 SERIAL UO To customer supplied Adapter computer with DB 25 Serial Interface Serial Interface Output on rear of Connector configured as Model 420 DCE If the interface is 1 DTE a Null Modem Adapter is required to exchange Transmit and The Model 4001 4002 and 4003 Receive lines are options available from Lake Shore Use whichever adapter that matches your computer serial interface connector Pin outs are described in Paragraph 6 4 LSCI Model 4003 RJ 11 To customer supplied to DB 9 Adapter computer with DB 9
55. ies probe serial number The latest probe serial number format is HXXXXX though there is room for up to a ten character response Probe Type Query TYPE 0 1 or2 Queries probe type 0 high sensitivity 1 high stability 2 ultra high sensitivity Set Gauss or Tesla Unit Status UNIT Gor UNIT T Nothing Sets unit status G gauss T tesla Gauss or Tesla Unit Query UNIT Gort Queries unit status G gauss T tesla Initiate Zero Probe Command ZCAL Nothing Initiates zero probe function Place probe in the Zero Gauss Chamber first and then enter the ZCAL command Remote Operation Remote Operation Lake Shore Model 420 Gaussmeter User s Manual This Page Intentionally Left Blank Lake Shore Model 420 Gaussmeter User s Manual CHAPTER 5 SERVICE 5 0 GENERAL This chapter covers General Troubleshooting Paragraph 5 1 Changing Power Settings and Fuse Ratings Paragraph 5 2 Rear panel Connector Definitions Paragraph 5 3 Serial Interface Cables and Adapters Paragraph 5 4 and Operating Software EPROM Replacement Paragraph 5 5 5 1 GENERAL TROUBLESHOOTING If the keyboard locks up hold Escape for about 20 seconds to reset the Model 420 to factory defaults The gaussmeter then requires the user to re enter setpoints and zero the probe If there is no power check the outlet and the connection at both ends of the power cord Next check the fuse Remove line cord then place a small slotted scre
56. lowed by kG for kilogauss G for gauss or mG for milligauss and formats field values over the Serial Interface accordingly 3 7 INTERFACE To use the Serial Interface set the Baud rate Press Interface to display the screen to the right Press Interface again to cycle through the choices of 300 1200 or 9600 Baud To accept the new rate either wait about 6 seconds until the display disappears automatically or press any key other than Interface 3 8 RELATIVE The relative function lets the user see small variations in larger fields To set the setpoint or center of the relative reading press Relative This captures the field reading nulling the present field After pressing Relative the Relative On message briefly appears on the lower line of the display followed by the selected setpoint SP The plus or minus deviation from that setpoint displays on the upper line A small delta signifies the relative display The relative feature also interacts with other features When Relative and Max Hold functions are used at the same time the relative reading still displays on the top line with proper annunciators but the bottom line shows the relative maximum instead of the relative setpoint Press Max Hold again to turn OFF the maximum hold function returning the relative reading to the display Press Relative On Off to turn OFF the relative function The Relative Off message briefly displays 3 9 ANALOG OUT
57. nal 200 uV max 200 uV max control current Operating temperature range 4 2 K to 375K 4 2 K to 375K Mean temperature coefficient of magnetic 0 01 K approx 0 01 K approx sensitivity Mean temperature coefficient of offset Iq 0 4 uV K max 0 4 uV K max nominal control current 0 Mean temperature coefficient of resistance 0 6 K max 0 6 K max Leads 34 AWG copper w Teflon insulation 34 AWG copper w Teflon insulation fo gt 3 fe a gt 3 A 6 Appendix A Lake Shore Model 420 Gaussmeter User s Manual 0 09 in max D 0 175 in max PZ f Axial Description Active area Input resistance Output resistance Nominal control current Ion Maximum continuous current non heat sinked Magnetic sensitivity Ic nominal control current Maximum linearity error sensitivity versus field Zero field offset voltage lc nominal control current Operating temperature range Mean temperature coefficient of magnetic sensitivity Mean temperature coefficient of offset Ic nominal control current Mean temperature coefficient of resistance Appendix A a lt _ 5 0 5in 1 25 in Lead Length t BS be ae mmm Active Area Figure B 7 Axial Hall Generator HGA 2010 Dimensions gt B Table B 2 Axial Hall Generator Specifications HGA 2010 HGA 3010 HGA 3030 General purpose axial high Instrumentation quality
58. nits to confirm the change A correctly spelled query without a returns nothing Misspelled commands and queries are ignored The term free field indicates a decimal point floats and can be placed at any appropriate place in the string of digits 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 term indicates where the user places terminating characters or where they appear on a returning character string from the Model 420 The following commands are available only over the computer interface there are no front panel equivalent commands CODE BRIGT FAST and SNUM To change number inputs to the field reading resolution first set them to zero Remote Operation 4 3 Lake Shore Model 420 Gaussmeter User s Manual Table 4 2 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
59. nstrument to factory default settings press and hold Max Reset for about 20 seconds Max Hold Off Auto Range Off Relative Off Interface 300 Range Highest range for probe AC DC DC Gauss Tesla Gauss Keypad Unlocked Other gaussmeter calibration information and probe data are not affected by this reset Zero the probe after completing this operation 3 12 PROBE CONSIDERATIONS This section covers several probe concerns to avoid damage and yield the best results Changing Probes Paragraph 3 15 1 Probe Handling Paragraph 3 15 2 Probe Operation Paragraph 3 15 3 and Accuracy Considerations Paragraph 3 15 4 For details of available Lake Shore Probes see Paragraph 6 2 3 12 1 Changing Probes CAUTION Connect the probe to the unit rear before applying power to the gaussmeter Probe memory may be erased if connected with power on Each probe includes a 512 byte Electrically Erasable Programmable Read Only Memory EEPROM The EEPROM stores specific information the gaussmeter requires for operation The information includes serial number and probe sensitivity and may also include field and temperature compensation data Upon power up probe memory downloads to the gaussmeter Probe memory includes available ranges and which error correction to apply To change probes first turn power off remove existing probe then plug in the new probe When power is restored the new probe characteristics download to the gaussmeter and normal op
60. or HGT 2100 Dimensions A 8 Appendix A Lake Shore Model 420 Gaussmeter User s Manual Table B 3 Transverse Hall Generator Specifications HGT 1010 HGT 2010 HGT 2100 HGT 3010 HGT 3030 Description General purpose General purpose Low cost high Instrumentation Instrumentation transverse 0 020 transverse high sensitivity quality quality transverse inch thick sensitivity surface mount transverse low ceramic package temperature coefficient ceramic package Active area 0 040 inch 0 005 x 0 005 0 005 x 0 005 0 040 inch 0 040 inch diameter circle inch square inch square diameter circle diameter circle Input resistance 450 to 900 ohms f 450 to 900 ohms Output resistance 550 to 1350 ohms 550 to 1350 ohms Nominal control 100 mA 1mA 5 mA 100 mA 100 mA current lcn Maximum continuous 300 mA 10 mA 10 mA 300 mA 300 mA current non heat sinked Magnetic sensitivity 7 7 to 12 5 mV kG 11 to 28 mV kG 55 to 140 mV kG 0 56 to 1 04 6 0 to 10 0 mV kG Uc nominal control mV kG current Maximum linearity 1 0 RDG 1 RDG 1 RDG 1 RDG 0 25 RDG error sensitivity 10 to 10 kG 10 to 10 kG 10 to 10 kG 20 to 20 kG 10 to 10 kG versus field 2 RDG 2 RDG 1 5 RDG 1 00 RDG 20 to 20 kG 20 to 20 kG 100 to 100 kG 30 to 30 kG Zero field offset 100 uV max 2 8 mV max 14 mV max 50 uV max 75 uV max voltage Ic nominal control current Operating 40 to 100 C 20 to 75 C 55 to 125
61. or1 Queries Auto Range status 0 Off 1 On Present Magnetic Field Reading FIELD XXX XX Returns sign five numbers and decimal point Places decimal appropriate to range Requires MULT and UNIT commands to fully define the reading Set Front Panel Keypad Lock Status LOCK 0orLOCK 1 Nothing Sets front panel keypad lock status 0 Unlocked 1 Locked Front Panel Keypad Lock Query LOCK Oorl Queries front panel keypad lock status 0 Unlocked 1 Locked Set Max Hold Status MAX O or MAX 1 Nothing Sets the Max Hold feature 0 Off 1 On Works with the MAXR and MAXC commands Max Hold Query MAX Oorl Queries Max Hold status 0 Off 1 On Works with the MAXR and MAXC commands Remote Operation MAXC Input Returned Remarks MAXR Input Returned Remarks MULT Input Returned Remarks RANGE Input Returned Remarks RANGE Input Returned Remarks REL Input Returned Remarks REL Input Returned Remarks RELR Input Returned Remarks RELS Input Returned Remarks Remote Operation Lake Shore Model 420 Gaussmeter User s Manual Initiate Max Clear Reset MAXC Nothing Initiate a Max Clear or reset Upon entry Max Hold zeros out and captures a new peak Max Reading Query MAXR XXX XX Queries Max Hold reading Returns sign five digits and decimal point Places decimal appropriate to range Probe Mul
62. oth may be grounded e Do not exceed the maximum continuous control current given in the specifications The Hall generator input is not isolated from its output In fact impedance levels on the order of the input resistance are all that generally exist between the two ports To prevent erroneous current paths which can cause large error voltages isolate the current supply from the output display or the down stream electronics A 4 Appendix A Lake Shore Model 420 Gaussmeter User s Manual o Hall Generator Model 120CS WU Current Source Digital Voltmeter Load resistor required for optimum linearity if specified C 450 U C 3 Figure B 3 Typical Hall Generator Hookup B4 0 USING A HALL GENERATOR WITH THE MODEL 420 To hookup a Hall generator to the Model 420 Gaussmeter use a Lake Shore Model MCBL 6 Cable Assembly The cable is 200 cm 79 inches long with a DA 15 connector on one end and four leads on the other The Hall generator is a four lead device The four leads are labeled cc Red Ic Black VH Blue and VH Yellow corresponding to the four leads on all Hall generators except for cryogenic models see Paragraph B2 5 The Model 420 has an input impedance of 420 Therefore the actual sensitivity at the gaussmeter input is less than the value given with the Hall generator due to drop in the leads and cable This is important because a sensitivity value is supposed to load into the cable PROM
63. part found to be defective in material or workmanship without charge to the owner for parts service labor or associated customary return shipping cost Replacement or repaired parts will be warranted for only the unexpired portion of the original warranty or 90 days whichever is greater All products are thoroughly tested and calibrated to published specifications prior to shipment Calibration Certifications are offered for 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 does not apply to defects resulting from improper installation product modifications made by others without Lake Shore s express written consent or from misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries or problems arising from normal wear or failure to follow instructions This warranty is in lieu of any other warranties expressed or implied including merchantability or fitness for a particular purpose which are expressly excluded The owner agrees that Lake Shore s liability with respect to this product shall be set forth in this warranty and incidental or consequential damages are expressly excluded CERTIFICATION Lake Shore certifies that this product has been inspected and tested in accordance with its published specifications and that this product met its published speci
64. right probe can be difficult Below are simple guidelines to help in the selection process 1 2 Match the probe to the application Do not buy more accuracy field range or fragility than necessary The thinner a probe the more fragile it is Avoid selecting an easily damaged probe based on a possible but not probable future application For instance avoid using an exposed device probe such as a Model MFT 3E03 type for general field measurements A damaged probe stem or sensor is irrepairable Metal enclosed probes such as the Model MMT 6J08 and MMA 2508 offer the greatest Hall sensor protection and are the most rugged Be cautious about aluminum stemmed transverse probes like the Model MMT 6J08 types if measuring AC magnetic fields Eddy currents in the aluminum can affect accuracy A superior choice for AC measurements is the Model MNT 4E04 type fiberglass epoxy stem probes Each probe type has several stem lengths User preferences or test set up dimensions usually determine final selection Longer stems are more susceptible to accidental bending mostly bothersome not catastrophic Stem length does not affect performance Be aware of the differences in the probe active areas shown on the data sheet A Hall effect probe indicates the average field value sensed over that total active area Thus when measuring magnetic fields with a high gradient across the sensor width choose the smallest active area practical rememberin
65. rvice in the United States or from the authorized sales service representative from which the product was purchased Instruments may not be accepted without a RGA number When returning an instrument for service Lake Shore must have the following information before attempting any repair Instrument model and serial number User name company address and phone number Malfunction symptoms Description of system Returned Goods Authorization RGA number oP NS Wrap instrument in a protective bag and use original spacers to protect controls Repack the system in the LSCI shipping carton if available and seal it with strong paper or nylon tape Affix shipping labels and FRAGILE warnings Write the RGA number on the outside of the shipping container or on the packing slip Because of their fragility Lake Shore probes ship in special cardboard and foam boxes Retain these boxes to store probes when not in use or return probes to Lake Shore for re calibration or repair Installation 2 1 Lake Shore Model 420 Gaussmeter User s Manual WARNING NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO TRAINED SERVICE PERSONNEL ANALOG OUTPUTS SERIAL UO Corrected Monitor PROBE INPUT i OO E CAUTION POWER OFF TO MATE PROBE Figure 2 1 Model 420 Rear Panel 2 3 DEFINITION OF REAR PANEL CONNECTIONS The Model 420 rear panel consists of the power and fuse assembly Serial UO Connector Corrected and Monitor Analog Output BNCs
66. stimation High Mobility III V Semiconductor a Indium arsenide b Gallium arsenide wl Figure B 1 Hall Generator Theory Ic Green or Black Appendix A A 3 Lake Shore Model 420 Gaussmeter User s Manual B2 2 ORIENTATION Hall generators come in two main configurations B axial and transverse Transverse devices are generally thin and rectangular They are applied successfully in magnetic circuit gaps surface ae measurements and general open field xy measurements Axial sensors are mostly cylindrical Their applications include ring magnet center bore measurements solenoids surface field Transverse detection and general field sensing B2 3 HANDLING B CAUTION Take care when handling the Hall SE generator it is very fragile Stressing it can alter its output and any excess force can easily Axial break it Broken Hall generators are Figure B 2 Axial and Transverse Configurations irrepairable Hall Generators are very fragile and require delicate handling The ceramic substrate used to produce the Hall Generator is very brittle Use the leads to move the Hall generator Do not handle the substrate The strength of the lead to substrate bond is about 7 ounces so avoid tension on the leads and especially avoid bending them close to the substrate The Hall Generator is also susceptible to bending and thermal stresses B2 4 POLARITY If the control current enters the red lead with 1 connected to t
67. tiplier Query MULT m k Or _ Queries probe multiplier m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Set Manual Range Status RANGE X Nothing Range depends on type of probe installed There are four ranges possible for each probe 0 highest through 3 lowest See Paragraph 3 4 Manual Range Query RANGE 0 1 2 or3 Queries manual range Range depends on type of probe installed There are four ranges possible for each probe 0 highest through 3 lowest See Paragraph 3 4 Set Relative Mode Status REL 0 Or REL 1 Nothing Sets Relative Mode Status 0 Off 1 On Relative Mode Query REL Dor Queries Relative Mode status 0 Off 1 On Relative Mode Reading Query RELR XXX XX Returns sign up to 5 digits and decimal point Places decimal appropriate to range Set Relative Mode Setpoint RELS XXX XX Nothing Enter sign up to 5 digits and decimal point Place decimal appropriate to range 4 7 RELS Input Returned Remarks SNUM Input Returned Remarks TYPE Input Returned Remarks UNIT Input Returned Remarks UNIT Input Returned Remarks ZCAL Input Returned Remarks 4 8 Lake Shore Model 420 Gaussmeter User s Manual Relative Mode Setpoint Query RELS XXX XX Returns sign up to 5 digits and decimal point Places decimal appropriate to range Probe Serial Number Query SNUM XXXXXXXXXX Quer
68. uency Type oe Temperature Fee oa Number Range 0 Range Reading Calibration ie Dect Pare ES DC 10 to 0 5 0 Cto ave op uHs 1 20 5 ao 1mG C 0 02 C MLA 5009 HJ 5009 HJ rong 400 Hz to Cc C 450 U 6 11 Figure 6 11 Definition of Lake Shore Gamma Probes 6 8 Accessories and Probes Lake Shore Model 420 Gaussmeter User s Manual APPENDIX A UNITS FOR MAGNETIC PROPERTIES Conversion from CGS to SI Units Quantit Gaussian Conversion SI amp i amp CGS emu Factor C Rationalized mks Magnetic flux density d Magnetic induction CG A gauss G tesla T Wb m m D oi 0 8 MOWING Teo oersted Oe Gb cm REI A Volume magnetization 10 Alm A m 4 1 F7 o 10 Dog AF Volume magnetization 10 47 RE gilbert Gb Ons ampere A l Wbem kg l 3 weber Wb volt Magnetic Flux Oe maxwell Mx Gecm2 second Vss 1 Magnetic moment m Am kg SS E emu emu erg G Asm joule per tesla J T Magnetic dipole moment j_ emu ergG 4 x 10 Wm M M BEE E dimensionless Henry per meter volume susceptibility X emu cm 47 x 10 H m Wb Aem Kp e Magnetic polarization 3 2i intensity of J emu cm 4n x 10 T Wb m magnetization Mass susceptibility cmvig emug next CH 8 5 3 Molar susceptibility cm mol emu mol we 10 dE 3 Permeability dimensionless 4m x10 Him Wbi Am Relative permeability not defined dimensionless 3 Volume energy
69. wdriver in the slot of the small door at the rear of the unit to access the fuse see Figure 5 1 For 100 120 V operation the fuse rating is 0 5 A and the fuse type is 3AG Slow Blow For 220 240 V operation the fuse rating is 0 25 A and the fuse type is 5x20 mm T Test fuse with ohmmeter Do not rely on visual inspection of fuse 5 2 Changing power SETTING and fuse RATING There are two basic power configurations domestic and foreign Domestic has a single fuse on the hot Foreign has a double fuse for the hot and neutral Units with power requirements specified at purchase are factory pre configured for the proper power setting If power settings are incorrect for your application use the procedure below to change power settings 1 Turn Off unit 2 Unplug line cord from rear of unit 3 Use small screwdriver to open fuse drawer 4 Pull out the fuse holder rotate until the proper voltage setting displays through the fuse drawer window Place fuse holder back in fuse drawer 5 Remove existing fuse s Replace with proper fuse ratings as follows 0 5 A for 100 120 VAC or 0 25 A for 220 240 VAC 6 Slide fuse drawer back into unit Plug line cord into rear of unit 8 Perform initial setup and system checkout procedure in Paragraph 2 4 Power On Off Screwdriver Fuse Switch Sbt Drawer Figure 5 1 Power Fuse Access N Service 5 1 Lake Shore Model 420 Gaussmeter User s Manual 5 3 REAR PANEL CONNECTOR DEFI

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