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Lake Shore Model 420 Gaussmeter User’s Manual

Service

5-1

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 screwdriver 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.

Turn Off unit.

Unplug line cord from rear of unit.

Use small screwdriver to open fuse drawer.

Pull out the fuse holder, rotate until the proper

voltage setting displays through the fuse drawer

window. Place fuse holder back in fuse drawer.

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.

Slide fuse drawer back into unit.

Plug line cord into rear of unit.

Perform initial setup and system checkout procedure in Paragraph 2.4.

Power On/Off

Switch

Fuse

Drawer

Screwdriver

Slot

Figure 5-1 Power Fuse Access

Summary of Contents for 420

Page 1: ...r 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...

Page 2: ...h in this warranty and incidental or consequential damages are expressly excluded CERTIFICATION Lake Shore certifies that this product has been inspected and tested in accordance with its published specifications and that this product met its published specifications at the time of shipment The accuracy and calibration of this product at the time of shipment are traceable to the United States Nati...

Page 3: ...General 3 1 3 1 Definitions of Front Panel Controls 3 1 3 1 1 Front Panel Keypad 3 1 3 1 2 Front Panel Display 3 2 3 2 Max Hold and Max Reset 3 2 3 3 Zero Probe 3 2 3 4 Range 3 3 3 5 AC DC 3 3 3 6 Gauss Tesla 3 4 3 7 Interface 3 4 3 8 Relative 3 4 3 9 Analog Out 3 4 3 10 Locking and Unlocking the Keypad 3 5 3 11 Factory Default Settings 3 5 3 12 Probe Considerations 3 5 3 12 1 Changing Probes 3 5 ...

Page 4: ... 4 5 5 Operating Software EPROM Replacement 5 5 6 ACCESSORIES AND PROBES 6 1 6 0 General 6 1 6 1 Accessories 6 1 6 2 Probe Selection Criteria 6 6 APPENDIX A UNITS FOR MAGNETIC PROPERTIES A 1 APPENDIX B HALL GENERATORS B 1 B1 0 General B 1 B2 0 Theory of Operation B 1 B2 1 Active Area B 1 B2 2 Orientation B 2 B2 3 Handling B 2 B2 4 Polarity B 2 B2 5 Lead Configurations B 2 B3 0 Hall Generator Gener...

Page 5: ...odel 4026 Dual Rack Mount Shelf 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 6 6 6 9 Definition of Lake Shore Axial Probes 6 7 6 10 Definition of Lake Shore Flexible Transverse Probes 6 8 6 11 Definition of Lake Shore Gamma Probes 6 8 B 1 Hall Generator Theory B 1 B 2 Axial and Transverse Configuration...

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Page 7: ...el keypad and message display The display has a resolution of 4 characters The Model 420 measures fields from 3 mG 0 3 µT 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...

Page 8: ...S 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 ...

Page 9: ...on a conductive work surface or in a conductive container An operator inserting or removing a device or assembly from a container must maintain contact with a conductive portion of the container Use only plastic bags approved for storage of ESD material 6 Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested 1 3 SAFETY SUMMARY Observe these general safe...

Page 10: ...n An Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away From Live Circuits Operating personnel must not remove instrument covers Refer component replacement and internal adjustments to qualified maintenance personnel Do not replace components with...

Page 11: ...esponsible 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 Service in the United States or from the authorized sales service representa...

Page 12: ...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 ti...

Page 13: ...e tip before placing the tip in the chamber 9 Place the probe in the zero gauss chamber and press the front panel Zero Probe key The display to the right appears 10 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 I...

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Page 15: ...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 whi...

Page 16: ...d 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 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 g...

Page 17: ... 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 ...

Page 18: ...he 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...

Page 19: ...o 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 operation may continue If the unit powers up with no probe attached the message to the right displays 3 12 2 Probe Handling CAUTIO...

Page 20: ...e 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 Paragrap...

Page 21: ...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 B Deviation from Perpendicular θ θ θ θ Error 0 0 5 10 15 20 30 45 0 4 1 5 3 4...

Page 22: ...Lake Shore Model 420 Gaussmeter User s Manual 3 8 Operation This Page Intentionally Left Blank ...

Page 23: ... 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 for a sample BASIC program to establish communications between the computer and the Model 420 SERIAL I O LSCI Model 4002 RJ 1...

Page 24: ...d Receives Using EIA Voltage Levels CR 0DH LF 0AH 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 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 4 1 3 Sample ...

Page 25: ...m 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 requ...

Page 26: ...RAM PRINT TIMEOUT 2000 Read timeout may need more BAUD 9600 TERM CHR 13 CHR 10 Terminators are CR LF OPEN COM1 BAUD N 8 1 RS FOR RANDOM AS 1 LEN 256 LOOP1 INPUT ENTER COMMAND or EXIT CMD Get command from keyboard CMD UCASE CMD Change input to upper case IF CMD EXIT THEN CLOSE 1 END Get out on Exit CMD CMD TERM PRINT 1 CMD Send command to instrument IF INSTR CMD 0 THEN Test for query RS If query re...

Page 27: ...UM Probe Serial Number Query 4 7 TYPE Probe Type Query 4 7 UNIT Set Gauss or Tesla Units 4 7 UNIT Gauss or Tesla Units Query 4 7 ZCAL Initiate Zero Probe Command 4 7 4 2 1 Command List Structure 4 2 2 Interface Commands Q Q Q QIDN Query Identification Input IDN Returned manufacturer model number serial number firmware date Format LSCI MODEL340 aaaaaa nnnnnn term Remarks Identifies the instrument m...

Page 28: ...uto Range status 0 Off 1 On FIELD Present Magnetic Field Reading Input FIELD Returned XXX XX Remarks Returns sign five numbers and decimal point Places decimal appropriate to range Requires MULT and UNIT commands to fully define the reading LOCK Set Front Panel Keypad Lock Status Input LOCK 0 or LOCK 1 Returned Nothing Remarks Sets front panel keypad lock status 0 Unlocked 1 Locked LOCK Front Pane...

Page 29: ...talled There are four ranges possible for each probe 0 highest through 3 lowest See Paragraph 3 4 RANGE Manual Range Query Input RANGE Returned 0 1 2 or 3 Remarks 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 REL Set Relative Mode Status Input REL 0 or REL 1 Returned Nothing Remarks Sets Rela...

Page 30: ...e is room for up to a ten character response TYPE Probe Type Query Input TYPE Returned 0 1 or 2 Remarks Queries probe type 0 high sensitivity 1 high stability 2 ultra high sensitivity UNIT Set Gauss or Tesla Unit Status Input UNIT G or UNIT T Returned Nothing Remarks Sets unit status G gauss T tesla UNIT Gauss or Tesla Unit Query Input UNIT Returned G or T Remarks Queries unit status G gauss T tes...

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Page 32: ......

Page 33: ... 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 config...

Page 34: ... C 450 U 5 3 Figure 5 3 Corrected and Monitor ANALOG OUTPUTS Connector Details 6 5 4 3 2 1 RJ 11 Receptacle SERIAL I O C 450 U 5 4 Figure 5 4 SERIAL I O RJ 11 Connector Details PIN DESCRIPTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Input NC NC ITEMP ITEMP NC NC Ic INPUT NC GND 1 Vcc A D CLK EE DATA Ic PIN DESCRIPTION 1 2 Analog Output Center Conductor Ground Connector Shell PIN DESCRIPTION 1 2 3 4 5 ...

Page 35: ...NOT USED 6 5 4 3 2 1 DB25 CONNECTOR RJ11 RECEPTACLE RxD Gnd TxD 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 Figure 5 7 Model 2002 RJ 11 to DB 25 Adapter Wiring Details 5 4 3 2 1 9 8 7 6 NOT USED 6 5 4 3 2 1 DB9 CONNECTOR RJ11 RECEPTACLE Gnd RxD TxD For Customer...

Page 36: ... 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 ...

Page 37: ...or 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 4065 Large...

Page 38: ...able Length 4 3 meters 14 feet C 450 U 6 1 Figure 6 1 Model 4001 RJ 11 Cable Assembly 43 mm 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 15 9 mm 0 63 inches C 450 U 6 3 Figure 6 3 Model 4003 RJ 11 to DE 9 Adapter ...

Page 39: ...m hex key Refer to Note Drawing shows right side mounting Left side mounting also possible Model 420 Gaussmeter C 450 U 6 4 Figure 6 4 Model 4022 Rack Mount Kit Refer to Installation Procedure 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 2 Place Gaussmeter on shelf 3 Use 5 64 inch 2 mm hex key to reinstall two 6 32 x ...

Page 40: ...se a bulk tape degausser Radio Shack P N 44 232 or equivalent 61 mm 2 4 in 32 2 mm 1 266 in Front View Side View 32 2 mm 1 266 in 12 2 mm 0 48 in diameter by 50 8 mm 2 in deep bore C 450 U 6 6 Figure 6 6 Model 4060 Standard Zero Gauss Chamber Depth of Opening 279 4 mm 11 in 52 4 mm 2 06 in Front View Side View 57 2 mm 2 25 in 19 mm 0 75 in diameter opening 304 8 mm 12 in 31 8 mm 1 25 in C 450 U 6 ...

Page 41: ... 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 5 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...

Page 42: ...E04 VH 4 MMT 6J02 VG 2 Alum DC MMT 6J04 VG 4 MMT 6J08 VG 8 MMT 6J18 VG 18 MNT 4E02 VG 2 MNT 4E04 VG 4 0 040 dia approx Rigid Glass Epoxy DC 10 to 400 Hz 0 150 0 050 Active Area 0 C to 75 C Op Temp Range Temperature Coefficient Max 0 09 Gauss per C 0 13 Gauss per C 0 015 per C 0 005 per C 0 061 max 0 061 max 0 045 max 0 045 max 0 180 0 005 0 180 0 005 0 140 0 005 0 140 0 005 DC 10 to 400 Hz MCT 316...

Page 43: ...10 0 005 0 020 dia approx Type HST 2 HSE 1 HST 2 HST 1 0 25 to 10 kG 0 13 G per C 0 010 C 0 125 dia 0 005 0 25 to 20 kG 0 187 dia 0 005 0 030 dia approx Fiber glass Epoxy Alum 0 187 dia 0 005 Fiber glass Epoxy 0 25 0 006 Alum Stainless Steel MMA 0602 TH MMA 0604 TH MMA 0608 TH MMA 0618 TH MMA 1302 UH MMA 1304 UH MMA 1308 UH MNA 1902 VH MNA 1904 VH MNA 1908 VH MMA 2502 VH MMA 2508 VH MNA 1902 VG MN...

Page 44: ...x 0 085 max 0 020 max 0 065 0 005 0 15 to 30 kG 0 25 to 30 kG 0 50 to 30 kG MFT 3E03 VH MFT 3E03 VG MFT 2903 VJ MFT 2903 VH 0 015 C 0 005 C 0 015 C 0 005 C 0 09 G C 0 13 G C 0 09 G C 0 13 G C HSE 1 HST 1 HSE 1 HST 2 C 450 U 6 10 Figure 6 10 Definition of Lake Shore Flexible Transverse Probes Cable Length 6 6 feet B L T W Active Sensing Length 3 125 A To Center of Active Volume Model Number Tempera...

Page 45: ... Volume energy density energy productk W erg cm 3 10 1 J m 3 Demagnetization factor D N dimensionless 1 4π dimensionless NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 4πM b Multiply a number in Gaussian units by C to convert it to SI e g 1 G x 10 4 T G 10 4 T c SI Système International d Unités has been adopted by the National Bureau of Standa...

Page 46: ...Lake Shore Model 420 Gaussmeter User s Manual A 2 Appendix A This Page Intentionally Left Blank ...

Page 47: ...ve 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 ca...

Page 48: ...IONS 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 Cur...

Page 49: ...ty 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 g...

Page 50: ...fications Cryogenic HGCA 3020 HGCT 3020 Description Cryogenic axial phenolic package Cryogenic transverse ceramic package Active area 0 030 inch diameter circle 0 040 inch diameter circle Input resistance 1 ohm 1 ohm Output resistance 1 ohm 1 ohm Nominal control current ICN 100 mA 100 mA Maximum continuous current non heat sinked 300 mA 300 mA Magnetic sensitivity IC nominal control current 0 56 t...

Page 51: ...m continuous current non heat sinked 10 mA 300 mA 300 mA Magnetic sensitivity IC nominal control current 11 to 28 mV kG 0 56 to 1 04 mV kG 6 0 to 10 0 mV kG Maximum linearity error sensitivity versus field 1 RDG 10 to 10 kG 2 RDG 20 to 20 kG 1 RDG 20 to 20 kG 1 5 RDG 100 to 100 kG 0 25 RDG 10 to 10 kG 1 00 RDG 30 to 30 kG Zero field offset voltage IC nominal control current 2 8 mV max 50 µV max 75...

Page 52: ... 028 in max over leads Figure B 8 Transverse Hall Generator HGT 1010 Dimensions 0 09 in Center of Active Area 0 175 in max 0 060 in max B 1 25 in 5 0 5 in Lead Length Figure B 9 Transverse Hall Generator HGT 2010 Dimensions 0 065 in 0 098 in 0 030 in 0 012 in typical 0 073 in 0 039 in B VH Ic VH Ic Figure B 10 Transverse Hall Generator HGT 2100 Dimensions ...

Page 53: ... sensitivity IC nominal control current 7 7 to 12 5 mV kG 11 to 28 mV kG 55 to 140 mV kG 0 56 to 1 04 mV kG 6 0 to 10 0 mV kG Maximum linearity error sensitivity versus field 1 0 RDG 10 to 10 kG 1 RDG 10 to 10 kG 2 RDG 20 to 20 kG 1 RDG 10 to 10 kG 2 RDG 20 to 20 kG 1 RDG 20 to 20 kG 1 5 RDG 100 to 100 kG 0 25 RDG 10 to 10 kG 1 00 RDG 30 to 30 kG Zero field offset voltage IC nominal control curren...

Page 54: ...HALLCAL EXE program 4 The program prompts for the Probe serial number Type any combination of 6 letters or numbers Press Enter when done 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 C...

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