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Lake Shore Model 421, User Manual

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Lake Shore Model 421 Gaussmeter User’s Manual 

 

 

5-8 

Accessories and Probes 

5.3  HELMHOLTZ COIL LOW FIELD STANDARDS 

Lake Shore offers three Helmholtz coils: 2.5-, 6-, and 12-inch diameter. Check the latest Lake Shore 
brochures or our website for any recent additions to this line. 

 

These coils are accurately calibrated using field standards maintained at Lake Shore. Most standards 
are traceable to physical standards such as a coil of carefully controlled dimensions, or in some cases, 
to proton resonance. The field strengths are measured on the basis of the field generated by a current 
through the coil. 

 

When combined with a customer-supplied power supply, these coils can be used as low-field reference 
magnets to compliment our set of standard reference magnets (defined in Paragraph 5.4). The power 
supply must be capable of 2 A output and a constant-current mode is recommended. 
 
 

 MH-2.5 

MH-6 

MH-12 

Inside Diameter 

2.5 inches 

6 inches 

12 inches 

Field Accuracy 

±0.5% 

Field Strength 

≈

30 G @ 1 A 

≈

25 G @ 1 A 

≈

12 G @ 1 A 

Field Homogeneity 

0.5% within a 

cylindrical volume 

0.75" long, 0.75" 

diameter, located at 

center of coil 

0.5% within a 

cylindrical volume 

1.6" long, 1.6" 

diameter, located at 

center of coil 

0.5% within a 

cylindrical volume 

3.2" long, 3.2" 

diameter, located at 

center of coil 

Coil Resistance/Inductance 

≈

3 

Ω

 / 6.3 mH 

≈

10 

Ω

 / 36 mH 

≈

20 

Ω

 / 93 mH 

Maximum Continuous Current 

2 A DC or AC RMS 

Operating Temperature Range 

10 to 40 

°

C (50 to 104 °F) 

 
 

 

 

P-421-5-08.bmp

 

Figure 5-8. Model MH-2.5 Helmholtz Coil 

Summary of Contents for Model 421

Page 1: ...actual 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 n...

Page 2: ... incidental or consequential damages so the above limitation may not apply to you LIMITED WARRANTY STATEMENT Continued 9 EXCEPT TO THE EXTENT ALLOWED BY APPLICABLE LAW THE TERMS OF THIS LIMITED WARRANTY STATEMENT DO NOT EXCLUDE RESTRICT OR MODIFY AND ARE IN ADDITION TO THE MANDATORY STATUTORY RIGHTS APPLICABLE TO THE SALE OF THE PRODUCT TO YOU CERTIFICATION Lake Shore certifies that this product h...

Page 3: ...hereby declare that the equipment specified conforms to the following Directives and Standards Application of Council Directives 73 23 EEC 89 336 EEC Standards to which Conformity is declared EN 61010 1 2001 Overvoltage II Pollution Degree 2 EN 61326 A2 2001 Class A Annex B Model Number 421 Ed Maloof Printed Name Vice President of Engineering Position ...

Page 4: ...nt this product may cause radio interference in which case the user may be required to take adequate measures The instrument was tested under normal operating conditions with sensor and interface cables attached If the installation and operating instructions in the User s Manual are followed there should be no degradation in EMC performance Pay special attention to instrument cabling Improperly in...

Page 5: ...UTS 2 4 2 7 RELAY TERMINAL BLOCK 2 4 2 8 INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE 2 5 3 OPERATION 3 1 3 0 GENERAL 3 1 3 1 DEFINITION OF FRONT PANEL CONTROLS 3 1 3 1 1 Front Panel Keypad 3 1 3 1 2 Front Panel Display 3 2 3 1 3 General Keypad Operation 3 3 3 2 GAUSS TESLA 3 3 3 3 AC DC 3 4 3 4 DISPLAY FILTER 3 4 3 5 MANUAL RANGE AND AUTO RANGE 3 5 3 6 ZERO PROBE 3 6 3 7 MAX HOLD AND MAX RESET 3 6...

Page 6: ... 5 8 5 4 REFERENCE MAGNETS 5 10 6 SERVICE 6 1 6 0 GENERAL 6 1 6 1 GENERAL MAINTENANCE PRECAUTIONS 6 1 6 2 ELECTROSTATIC DISCHARGE 6 1 6 2 1 Identification of Electrostatic Discharge Sensitive Components 6 2 6 2 2 Handling Electrostatic Discharge Sensitive Components 6 2 6 3 LINE VOLTAGE SELECTION 6 2 6 4 FUSE REPLACEMENT 6 3 6 5 REAR PANEL CONNECTOR DEFINITIONS 6 4 6 5 1 Serial Interface Cable Wir...

Page 7: ...robes 5 7 5 7 Definition of Lake Shore Flexible Axial Probe 5 7 5 8 Model MH 2 5 Helmholtz Coil 5 8 5 9 Model MH 6 Helmholtz Coil 5 9 5 10 Model MH 12 Helmholtz Coil 5 9 5 11 Lake Shore Reference Magnets 5 10 5 12 Model 4060 Standard Zero Gauss Chamber 5 11 5 13 Model 4065 Large Zero Gauss Chamber 5 11 5 14 Model RM 1 2 Rack Mount Kit 5 12 5 15 Model RM 2 Dual Rack Mount Shelf 5 13 6 1 Power Fuse ...

Page 8: ...ties 4 5 4 3 Visual Basic Serial Interface Program 4 6 4 4 Quick Basic Serial Interface Program 4 7 4 5 Serial Interface Commands 4 10 B 1 Conversion from CGS to SI Units B 1 B 2 Recommended SI Values for Physical Constants B 2 C 1 Cryogenic Hall Generator Specifications C 5 C 2 Axial Hall Generator Specifications C 6 C 3 Transverse Hall Generator Specifications C 7 ...

Page 9: ...he Serial Interface Details on accessories and probes are provided in Chapter 5 Limited service and rear panel connector definitions are contained in Chapter 6 Appendix A is a glossary of terminology Appendix B provides units for magnetic properties Finally Appendix C provides information on Hall sensors and the Hallcal exe program 1 1 PRODUCT DESCRIPTION The Model 421 Hall Effect Gaussmeter is th...

Page 10: ...robe of customer choice A wide range of additional probes is available including Transverse Axial Flexible Transverse and Gamma Probes Refer to Paragraph 5 2 for a complete list Lake Shore probes are factory calibrated for accuracy and interchangeability Calibration data is loaded into a PROM located in the probe connector so that it does not have to be entered by the user Lake Shore can also cust...

Page 11: ...n Software Support LabView Driver consult Lake Shore for availability Compatible with Model 420 command set Alarm Settings High low setpoint Inside Outside Audible Sort Actuators Display annunciator sort message beeper relay Relay Number 1 Contacts N O N C and common C Contact Rating 30 VDC at 2 A Operation Follows alarm Connector Detachable terminal block Monitor Analog Output Configuration Real ...

Page 12: ...ug it into an approved three contact outlet or use a three contact adapter with the grounding wire green firmly connected to a ground safety ground at the power outlet The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Do Not Operate In An Explosive Atmosphere Do not operate the instrument in the pr...

Page 13: ...e to file proper claims promptly with the carrier and insurance company Please advise Lake Shore Cryotronics of such filings In case of parts or accessory shortages advise Lake Shore immediately Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment The standard Lake Shore Cryotronics Inc Warranty is included on the A Page immediately behind the title pag...

Page 14: ...AUTION Verify AC Line Voltage shown in the fuse holder window is appropriate for the intended AC power input Also remove and verify the proper fuse is installed before plugging in and turning on the instrument CAUTION Always turn off the instrument before making any rear panel connections This is especially critical when making probe to instrument connections 421_Rear bmp Description Pin Definitio...

Page 15: ...rounded three pronged receptacle 2 4 3 Power Switch The power switch turns the instrument On and Off and is located in the line input assembly on the instrument rear When l is raised the instrument is On When O is raised the instrument is Off 120 100 120 220 240 V 10 6 Voltage 50 60 Hz 40 VA MAX 100 120V 220 240V 0 5 A T 250V 0 25 A T 250V 0 25 1 25 5 20mm Line Cord Input Power Switch O Off l On F...

Page 16: ...ayonet 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 is updated at the same rate as the display The 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 wa...

Page 17: ...mbscrews to tighten connector to unit 5 Ensure any other rear panel connections SERIAL I O or ANALOG OUTPUTS are connected before applying power to the unit 6 Plug line cord into receptacle 7 Turn the power switch to the on l position The front panel display should turn on and the following message briefly appear Lake Shore 421 Field Monitor 8 The normal gaussmeter display will now appear A typica...

Page 18: ...st be exercised when handling the probe The tip of the probe is very fragile Any excess force may break the probe NOTE Probe readings are dependent upon the angle of the tip in relation to the magnetic field This and other effects on probe operation are explained in Paragraph 3 16 12 Carefully place probe into reference magnet You may have to hunt around a bit for the maximum reading For this exam...

Page 19: ...n the front panel are defined as follows Note the following are abbreviated descriptions of each key A more detailed description of each function is provided in subsequent paragraphs Max Reset Works with the Max Hold function Clears Max reading back to current reading Press and hold to reset parameters to default values This key also acts as an escape key during numeric entry Max Hold Turns the Ma...

Page 20: ... or outside the setpoint range and turn the sort feature on or off s Toggles between various settings shown in the display and increments a numerical display t Toggles between various settings shown in the display and decrements a numerical display Enter Accepts changes to parameter setting 3 1 2 Front Panel Display In normal operation the 2 row by 20 character vacuum fluorescent display provides ...

Page 21: ...5 digits of resolution in any field range available for the probe being used To begin number entry look at the range and resolution of the present parameter value If it is too small to accommodate the new value or too large to allow appropriate resolution change the setting range by pressing the Range key Pressing the Range key will cycle through all available setting ranges and zero the setting v...

Page 22: ... The RMS value is available over the Serial Interface A DC voltage representation of the RMS display reading is available from the Corrected Analog Output while a true analog waveform is available from the Monitor Analog Output In fact the Monitor Analog Output is not affected by the selection of AC or DC The resolution of AC RMS readings is fixed at 3 digits P 421 3 3 bmp Figure 3 3 Model 421 AC ...

Page 23: ...0 01 mG 0 01 G 0 001 G 0 1 mG 0 01 G 0 001 G 0 1 mG For manual ranging pressing the Range key and the following display will appear Select With 3 000 kG Use the s or t keys to toggle through the allowable full scale ranges for the probe installed Press the Enter key to accept the new setting In Auto Range mode the Model 421 selects the range with the best resolution for the field being measured It...

Page 24: ...erted press the Zero Probe key and observe the following display Press Again With Probe At Zero Press the Zero Probe key The CALIBRATING message is briefly displayed followed by a return to the normal display The probe is now calibrated For best results periodic zeroing of the probe is recommended 3 7 MAX HOLD AND MAX RESET The Max Hold function displays the largest field magnitude measured since ...

Page 25: ...he Relative key turns off the relative function The Relative Off message is briefly displayed 3 9 ALARM AND RELAY The alarm feature can be easily configured to perform several different tasks including error detection and limit testing The most powerful application is manual magnet testing and sorting A display annunciator message display beeper and relay are all available to indicate an active al...

Page 26: ...change that digit to the desired value Digits should be set to zero if not used Press the Enter key to advance to the next digit Continue until all digits are set When the Enter key is pressed on the last digit the setting value will be stored If a mistake is made press the Range key to select a new range and start over or press Max Reset to escape out of the setting function After entering the de...

Page 27: ...nside see examples below To select inside outside alarm operation continue from Audible On Off screen or press and hold the Alarm key until the Audible setting window appears then press Enter until the following message appears Select With Alarm In Out Use the s or t keys to cycle between the alarm triggered inside In or outside Out alarm setpoints Press Enter to accept the changes Model 421 can b...

Page 28: ...ide setup is useful in situations where the user is looking for an indication of a good reading such as incoming inspections For example you may be sorting a number of 1 kG magnets The magnets have an acceptable tolerance of 0 25 kG With the high alarm point set to 1 25 kG and the low alarm point at 0 75 kG the following diagram illustrates when the alarm would be active or normal 0 kG 1 kG 2 kG 3...

Page 29: ...ngs per second A Fast Data Mode has been included to increase the data rate when operating with the Serial Interface While the corrected analog output update rate does correspond to the Fast Data Mode the front panel display will not operate in this mode When the Model 421 is operating in Fast Data Mode the user will see the following front panel display Fast Data Mode There are two methods for pl...

Page 30: ...The overall brightness of the front panel vacuum florescent display is user controllable Press and hold the Relative key until you see the following display Select With Brightness Use the s or t keys until you see the desired brightness Press the Enter key to accept the new setting There are four levels of brightness The brightness can also be set using the BRIGT command via the Serial Interface U...

Page 31: ...O PROBE Power off attach 3 16 2 Probe Handling Although every attempt has been made to make the probes as sturdy as possible the probes are still fragile This is especially true for the exposed sensor tip of some transverse probes Care should be taken during measurements that no pressure is placed on the tip of the probe The probe should only be held in place by securing at the handle The probe st...

Page 32: ...est results the instrument and probe should 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 If the exact direction of the magnetic field is unknown the proper magnitude is determined by turning on Max Hold and slowly adjusting the probe As the probe turns and the measured field...

Page 33: ...gh Stability HST probes exhibit a low temperature coefficient of gain due to the inherent thermal stability of the materials used in its construction Probe readings are dependent 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 ...

Page 34: ...Lake Shore Model 421 Gaussmeter User s Manual 3 16 Operation This Page Intentionally Left Blank ...

Page 35: ...xist for connecting the instrument to computers with either 9 or 25 pin connectors Paragraph 6 5 gives the most common pin assignments for 9 and 25 pin connectors Please note that not all pins or functions are supported by the Model 421 The instrument serial connector is the plug half of a mating pair and must be matched with a socket on the cable If a cable has the correct wiring configuration bu...

Page 36: ... parity is included in each character ASCII letter and number characters are used most often as character data Punctuation characters are used as delimiters to separate different commands or pieces of data Two special ASCII characters carriage return CR 0DH and line feed LF 0AH are used to indicate the end of a message string Table 4 1 Serial Interface Specifications Connector Type Connector Wirin...

Page 37: ...ll times The instrument can not initiate communication determine which device should be transmitting at a given time or guarantee timing between messages All of this is the responsibility of the user program When issuing commands only the user program should Properly format and transmit the command including terminators as one string Guarantee that no other communication is started for 50 ms after...

Page 38: ...Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better with a serial interface It uses the COM1 communications port at 9600 Baud Use the following procedure to develop the Serial Interface Program in Visual Basic 1 Start VB6 2 Choose Standard EXE and select Open 3 Resize form window to desired size 4 On the ...

Page 39: ...lic gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 4 3 c In the Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form_Load Add the code to this subroutine as shown in Table 4 3 d Double Click on the Time...

Page 40: ...op Until gSend True Loop until Send button pressed gSend False Set Flag as false strCommand frmSerial txtCommand Text Get Command strReturn Clear response display strCommand UCase strCommand Set all characters to upper case If strCommand EXIT Then Get out on EXIT End End If frmSerial MSComm1 Output strCommand Term Send command to instrument If InStr strCommand 0 Then Check to see if query While Ze...

Page 41: ...l Interface Program CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may need more BAUD 9600 TERM CHR 13 CHR 10 Terminators are CR LF OPEN COM1 BAUD O 7 1 RS FOR RANDOM AS 1 LEN 256 LOOP1 LINE 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 Sen...

Page 42: ...ndicates kilo gauss etc RESPONSE k term ENTER COMMAND RANGE 0 Range command Instrument will change the field range to the highest setting No response will be sent ENTER COMMAND RANGE Range query Instrument will return a string with the present range setting RESPONSE 0 term ENTER COMMAND RANGE 0 RANGE Range command followed by range query Instrument will change range to highest setting then return ...

Page 43: ...ph provides a summary of the Serial Interface Commands The summary is divided into two command groups Interface Commands and Device Specific Commands Interface Commands are detailed in Paragraph 4 2 1 Device specific commands are detailed in Paragraph 4 2 2 A list of all commands is provided in Table 4 5 Command Name Brief Description of Function Syntax of what user must input ALMH Input Returned ...

Page 44: ...mmand 4 14 AUTO Auto Range Query 4 14 BRIGT Display Brightness Command 4 14 BRIGT Display Brightness Query 4 15 Command Function Page FAST Fast Data Mode Command 4 15 FAST Fast Data Mode Query 4 15 FIELD Field Reading Query 4 15 FIELDM Field Multiplier Query 4 15 FILT Display Filter Command 4 15 FILT Display Filter Query 4 15 LOCK Keypad Lock Command 4 16 LOCK Keypad Lock Query 4 16 MAX Max Hold C...

Page 45: ...dicates no serial number included date Instrument firmware revision date Example LSCI MODEL421 0 070199 QRST Reset Command Input QRST term Remarks This command resets the instrument to its power up state Similar to turning the power off and back on again BAUD Set Serial Interface Baud Rate Input BAUD baud term Format n baud 0 300 1 1200 and 2 9600 baud BAUD Serial Interface Baud Rate Query Input B...

Page 46: ... On Off Query Input ALARM term Returned state term Format n Refer to command for description ALMB Audible Alarm Beeper Enable Disable Command Input ALMB state term Format n state 0 Disabled 1 Enabled ALMB Audible Alarm Beeper Enable Disable Query Input ALMB term Returned state term Format n Refer to command for description ALMH High Alarm Setpoint Command Input ALMH field value term Format nnn nn ...

Page 47: ...s Instructs alarm feature to cause an active alarm state when the field reading is either inside of or outside of the high and low setpoint values Refer to Paragraph 3 9 ALMIO Alarm Inside Outside Query Input ALMIO term Returned inout term Format n Refer to command for description ALML Low Alarm Setpoint Command Input ALML field value term Format nnn nn field value Enter sign 4 or 5 digits and pla...

Page 48: ...rm status ALMSORT Sort Pass Fail Command Input ALMSORT state term Format n state 0 Off 1 On ALMSORT Sort Pass Fail Query Input ALMSORT term Returned state term Format n Refer to command for description AUTO Auto Range Command Input AUTO state term Format n state 0 Auto Range Off 1 Auto Range On Refer to Paragraph 3 5 AUTO Auto Range Query Input AUTO term Returned state term Format n Refer to comma...

Page 49: ...Input FAST term Returned state term Format n Refer to command for description FIELD Magnetic Field Reading Query Input FIELD term Returned field value term Format nnn nn field value Returns sign 4 or 5 digits and places decimal point appropriate to range Remarks Use FIELDM to determine units multiplier and UNITS to determine gauss or tesla units FIELDM Field Reading Multiplier Query Input FIELDM t...

Page 50: ...ds Refer to Paragraph 3 7 MAX Max Hold Query Input MAX term Returned state term Format n Refer to command for description MAXC Max Reset Command Input MAXC term Remarks This command initiates a Max Reset Upon entry the Max Hold function is zeroed out and a new peak is captured Refer to Paragraph 3 7 MAXR Max Reading Query Input MAXR term Returned field value term Format nnn nn field value Returns ...

Page 51: ...ferent from front panel operation described in Paragraph 3 8 From the front panel the current reading is captured as the setpoint when Relative is turned on However when activated by remote command the initial relative setpoint is zero The RELS command is used to enter a setpoint REL Relative Mode Query Input REL term Returned state term Format n Refer to command for description RELR Relative Mode...

Page 52: ...m Returned setpoint term Format nnn nn Refer to command for description Remarks Use RELSM to determine units multiplier RELSM Relative Mode Setpoint Multiplier Query Input RELSM term Returned multiplier term Format a multiplier µ micro 10 6 m milli 10 3 blank unity k kilo 103 Remarks Used with RELS query SNUM Probe Serial Number Query Input SNUM term Returned serial term Format annnnnnnnn serial T...

Page 53: ...m Format a unit G gauss T tesla Refer to Paragraph 3 2 UNIT Gauss or Tesla Unit Query Input UNIT term Returned unit term Format a Refer to command for description ZCAL Zero Probe Command Input ZCAL term Remarks This command initiates the Zero Probe function Place probe in the Zero Gauss Chamber first and then enter the ZCAL command Refer to Paragraph 3 6 ...

Page 54: ...Lake Shore Model 421 Gaussmeter User s Manual 4 20 Remote Operation This Page Intentionally Left Blank ...

Page 55: ...ls are available as follows Consult factory for other post heights 4030 12 Hall probe stand with 12 inch tall post and probe holder to accept 3 8 inch diameter Hall probe handle 4030 24 Hall probe stand with 24 inch tall post and probe holder to accept 3 8 inch diameter Hall probe handle 4060 Standard Zero Gauss Chamber Used for standard probe field nulling Size 32 32 61 mm 1 3 1 3 2 4 inches Bore...

Page 56: ...ter 1 kG 1 MRA 312 2K Axial Reference Magnet 0 312 inside diameter 2 kG 1 MRT 062 200 Transverse Reference Magnet 0 062 gap 200 G 1 MRT 062 500 Transverse Reference Magnet 0 062 gap 500 G 1 MRT 062 1K Transverse Reference Magnet 0 062 gap 1 kG 0 5 MRT 062 2K Transverse Reference Magnet 0 062 gap 2 kG 0 5 MRT 062 5K Transverse Reference Magnet 0 062 gap 5 kG 0 5 MRT 062 10K Transverse Reference Mag...

Page 57: ...est set up dimensions usually determine the final selection Longer stems are more susceptible to accidental bending in many cases not catastrophic but bothersome Stem length does not affect performance 6 Be aware of the differences in the probe active areas shown on the data sheet A Hall effect probe will indicate the average field value sensed over that total active area Thus when measuring magne...

Page 58: ... mating gaussmeter Application is optimum when fields are homogeneous over lengths greater than 1 foot The active sensing length of the gamma probe is 3 125 inches Model No Zero Calibration MLA 5006 HJ DC 10 to 400 Hz 0 5 to 2 gauss 0 C to 75 C 1 mG C 0 02 C Frequency Range Corrected Accuracy of Reading Operating Temperature Range Type UHS 1 0 25 0 03 0 5 2 2 W T A L 5 7 Temperature Coefficient Ma...

Page 59: ...x 0 045 max 0 180 0 005 0 180 0 005 0 150 0 005 0 150 0 005 DC 10 to 400 Hz MCT 3160 WN 61 1 0 25 dia 0 010 0 210 0 050 Stainless Steel 1 5 K to 350 K Corrected Accuracy of rdg Type HSE 1 HST 2 HST 1 0 010 per C 0 25 to 30 kG 0 15 to 30 kG 2 to 100 kG One probe is included with the purchase of the Model 421 Model numbers shown in bold are the probes available to choose from Transverse eps Figure 5...

Page 60: ...E 1 HST 2 HST 1 0 25 to 10 kG 0 13 G per C 0 01 per C MMA 0802 UH 2 0 125 MMA 0804 UH 4 0 125 MMA 0808 UH 8 0 125 0 080 dia 0 005 0 25 to 20 kG MNA 1902 VH 2 0 125 MNA 1904 VH 4 0 125 MNA 1908 VH 8 0 125 0 187 dia 0 005 0 030 dia approx Fiber glass Epoxy Alum MNA 1902 VG 2 0 125 MNA 1904 VG 4 0 125 MNA 1908 VG 8 0 125 0 187 dia 0 005 Fiber glass Epoxy 0 25 dia 0 006 Stainless Steel 0 005 0 003 0 0...

Page 61: ...G 0 25 to 30 kG 0 09 G C 0 13 G C 0 015 C 0 005 C L S This table is for L 15 0 5 inches and S 0 75 inch MFT 4F15 VH DC 10 to 400 Hz 0 25 to 30 kG 0 09 G C 0 015 C MFT 4F15 VG 0 15 to 30 kG 0 C to 75 C 0 13 G C 0 005 C 0 040 dia approx Flexible Tubing Epoxy Fiber glass HSE 1 HST 2 0 150 0 005 0 045 max 0 150 0 050 Flexible_Transverse eps Figure 5 6 Definition of Lake Shore Flexible Transverse Probe...

Page 62: ...d power supply these coils can be used as low field reference magnets to compliment our set of standard reference magnets defined in Paragraph 5 4 The power supply must be capable of 2 A output and a constant current mode is recommended MH 2 5 MH 6 MH 12 Inside Diameter 2 5 inches 6 inches 12 inches Field Accuracy 0 5 Field Strength 30 G 1 A 25 G 1 A 12 G 1 A Field Homogeneity 0 5 within a cylindr...

Page 63: ...Lake Shore Model 421 Gaussmeter User s Manual Accessories and Probes 5 9 P 421 5 09 bmp Figure 5 9 Model MH 6 Helmholtz Coil P 421 5 10 bmp Figure 5 10 Model MH 12 Helmholtz Coil ...

Page 64: ...s ranging from 100 G to 20 kG but the most widely used value is 1 kG Reference magnets accuracy is typically 0 5 except for magnets of 200 G or less for these magnets the limit of error is generally 1 The reference magnet gap is nominally 0 060 inch but may range from 0 040 to 0 250 inch for special units The usable plateau in the reference gap generally encompasses an area of about 0 5 square inc...

Page 65: ...rofessional degausser is available a bulk tape degausser Verity VS250 Data Devices PF211 or equivalent may be used 61 mm 2 4 in 32 2 mm 1 3 in 32 2 mm 1 3 in 12 2 mm 0 5 in diameter by 50 8 mm 2 in deep bore Front View Side View 4060_Chamber eps Figure 5 12 Model 4060 Zero Gauss Chamber Depth of Opening 279 4 mm 11 in 52 4 mm 2 1 in 57 2 mm 2 3 in 19 mm 0 8 in diameter opening 304 8 mm 12 in 31 8 ...

Page 66: ...le 107 051 01 2 5 Screw 6 32 1 2 Inch 0 035 4 FHMS Phillips 6 Screw 8 32 3 8 Inch 0 081 6 FHMS Phillips Item Description P N Qty 1 2 3 4 6 5 5 6 6 4 Customer must use 5 64 2 mm hex key to remove four existing screws from sides of instrument NOTE Refer to Note Unit on right side mounting shown Unit on left side also possible RM12_Rack eps Figure 5 14 Model RM 1 2 Rack Mount Kit ...

Page 67: ...n 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 1 4 black button head screws through side of rack into corresponding holes in the side of the Gaussmeter Installation Procedure Refer to Installation Procedure RM2_Dual_Rack eps Figure 5 15 Model RM 2 Dual Rack Mount Shelf ...

Page 68: ...Lake Shore Model 421 Gaussmeter User s Manual 5 14 Accessories and Probes This Page Intentionally Left Blank ...

Page 69: ... another person nearby capable of rendering aid If there is no power verify the power cord is plugged into a live outlet and that both ends are securely plugged in Next check the fuse Use this procedure to periodically clean the Model 421 to remove dust grease and other contaminants 1 Clean front and back panels and case with soft cloth dampened with a mild detergent and water solution NOTE Do not...

Page 70: ...e 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 6 3 LINE VOLTAGE SELECTION Use the following procedure to change the ins...

Page 71: ...t Test fuse with ohmmeter Do not rely on visual inspection of fuse WARNING To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures CAUTION For continued protection against fire hazard replace only with the same fuse type and rating specified for the line for the line voltage selected 1 Locate line input assembly on the instrument re...

Page 72: ...At Rear Of Model 421 C 480 6 2 eps PIN DESCRIPTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Input Analog Signal No Connection No Connection No Connection No Connection No Connection No Connection IC Input Analog Signal Ground No Connection Digital Ground 5 Volts Power Output To Probe EEPROM EE CLK Output To Probe EEPROM EE DATA Serial Input From Probe EEPROM IC Figure 6 2 PROBE INPUT Connector Details ...

Page 73: ... 7 6 9 View Looking At Rear Of Model 421 C 421 6 5 eps Model 421 Gaussmeter DTE Computers and Printers DTE DE 9P DB 25P DE 9P Pin Description Pin Description Pin Description 1 No Connection 2 TD out 1 DCD in 2 Receive Data RD in 3 RD in 2 RD in 3 Transmit Data TD out 4 RTS out 3 TD out 4 Data Terminal Ready DTR out 5 CTS in 4 DTR out 5 Ground GND 6 DSR in 5 GND 6 Data Set Ready DSR in 7 GND 6 DSR ...

Page 74: ... 7 RTS out 7 DTR tied to 4 8 CTS in 8 NC 1 DCD in Model 421 to PC Serial Interface PC with DE 25P Model 421 DE 9P Standard Null Modem Cable DE 9S to DB 25S PC DB 25P 5 GND 7 GND 2 RD in 2 TD out 3 TD out 3 RD in 1 NC 4 RTS out 7 DTR tied to 4 5 CTS in 8 NC 8 DCD in 6 DSR in 20 DTR out 4 DTR out 6 DSR in Model 421 to PC Interface using Null Modem Adapter Model 421 DE 9P Null Modem Adapter PC DE 9P ...

Page 75: ...ing software for the Model 421 is contained on one Erasable Programmable Read Only Memory EPROM Integrated Circuit IC The reference designator for the EPROM is U36 Lake Shore Part Number 113 591 The EPROM has a sticker on top labeled with M421 HEX and the date Use the following procedure to replace the EPROM CAUTION The EPROM is an Electrostatic Discharge Sensitive ESDS device Wear shock proof wri...

Page 76: ...ssages that may be seen during normal operation OL Field range has been exceeded Refer to Paragraph 3 5 to change Range No Probe No probe attached to the instrument at power up Power the instrument off attach a probe and power it on again Locked Keypad is locked to prevent accidental parameter changes To unlock keypad refer to Paragraph 3 13 Error 1 NOVRAM memory is physically malfunctioning Conta...

Page 77: ...ction and placed one meter apart in a vacuum would produce between these conductors a force equal to 2 10 7 newton per meter of length 2 This is one of the base units of the SI ampere turn A MKS unit of magnetomotive force equal to the magnetomotive force around a path linking one turn of a conducting loop carrying a current of one ampere or 1 26 gilberts ampere meter A m The SI unit for magnetic ...

Page 78: ...nsitivity of a physical quantity to a stimulus expressed in dimensionless terms The dimensionless temperature sensitivity of a resistance temperature sensor is expressed as Sd T R dR dT which is also equal to the slope of R versus T on a log log plot that is Sd d lnR d lnT Note that the absolute temperature in kelvin must be used in these expressions drift instrument An undesired but relatively sl...

Page 79: ... whose output waveform is the time integral of its input waveform 1 international system of units SI A universal coherent system of units in which the following seven units are considered basic meter kilogram second ampere kelvin mole and candela The International System of Units or Système International d Unités SI was promulgated in 1960 by the Eleventh General Conference on Weights and Measures...

Page 80: ...of magnetic fields 1 mains See line voltage Maxwell Mx A cgs electromagnetic unit of magnetic flux equal to the magnetic flux which produces an electromotive force of 1 abvolt in a circuit of one turn link the flux as the flux is reduced to zero in 1 second at a uniform rate 1 MKSA System of Units A system in which the basic units are the meter kilogram and second and the ampere is a derived unit ...

Page 81: ...y 2 n for any given range Resolution should not be confused with accuracy root mean square RMS The square root of the time average of the square of a quantity for a periodic quantity the average is taken over one complete cycle Also known as effective value 1 RS 232C Bi directional computer serial interface standard defined by the Electronic Industries Association EIA The interface is single ended...

Page 82: ... when it is placed 1 cm away from a like pole the force between the two is 1 dyne vector A quantity that has both magnitude and direction and whose components transform from one coordinate system to another in the same manner as the components of a displacement Also known as a polar vector 1 volt V The difference of electric potential between two points of a conductor carrying a constant current o...

Page 83: ...imensionless Volume energy density energy product k 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 10 4 T G 10 4 T c SI Système International d Unités has been adopted by the National Burea...

Page 84: ... 10 15 J Hz 1 C 1 Josephson Frequency Voltage Ratio 2e h 483 5939 THz V 1 Quantum of Circulation h 2me h me 3 6369 10 4 J Hz 1 kg 1 7 2739 10 4 J Hz 1 C 1 Rydberg Constant R 1 0974 10 7 m 1 Proton Moment in Nuclear Magnetons µp µN 2 7928 Bohr Magneton µB eh 2me 9 2741 10 24 J T 1 Proton Gyromagnetic Ratio γp 2 6752 10 8 s 1 T 1 Diamagnetic Shielding Factor Spherical H2O Sample 1 σ H2O 1 0000 Molar...

Page 85: ...o a magnetic field these moving charged particles experience a force perpendicular to both the velocity and magnetic field vectors This force causes the charging of the edges of the conductor one side 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 fo...

Page 86: ...ENTATION Hall generators come in two main configurations axial and transverse Transverse devices are generally thin and rectangular in shape They are applied successfully in magnetic circuit gaps surface measurements and general open field measurements Axial sensors are mostly cylindrical in shape Their applications include ring magnet center bore measurements solenoids surface field detection and...

Page 87: ...Clear VH Input Control Current Output Hall Voltage The Model HGCA 3020 and HGCT 3020 Hall generators have 34 AWG stranded copper with Teflon insulation and have the following lead configuration Red IC Black IC Blue VH Yellow VH Input Control Current Output Hall Voltage C3 0 HALL GENERATOR GENERIC HOOKUP The Hall voltage leads may also be connected directly to a readout instrument such as a high im...

Page 88: ...Lake Shore has no control of the conditions beyond the cable the customer must accept responsibility for accuracy and compatibility Finally Manganin wire is not usually acceptable for cryogenic installations The resistance of Manganin wire is often too high In cryogenic applications Hall generators are normally connected using twisted pairs of copper wire such as 34 gauge Teflon insulated There ar...

Page 89: ...ations Cryogenic HGCA 3020 HGCT 3020 Description Cryogenic axial phenolic package Cryogenic transverse ceramic package Active area approximate 0 030 inch diameter circle 0 040 inch diameter circle Input resistance approximate 1 ohm 1 ohm Output resistance approximate 1 ohm 1 ohm Nominal control current ICN 100 mA 100 mA Maximum continuous current non heat sinked 300 mA 300 mA Magnetic sensitivity ...

Page 90: ...ce approximate 1 ohm 2 ohms 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 55 to 1 05 mV kG 6 0 to 10 0 mV kG Maximum linearity error sensitivity versus field 1 RDG 30 to 30 kG 1 5 RDG 100 to 100 kG 0 30 RDG 10 to 10 kG 1 25 RDG 30 to 30 kG Zero field offset voltage IC nominal control current 50 µ...

Page 91: ...ed 300 mA 300 mA 300 mA Magnetic sensitivity IC nominal control current 7 5 to 12 5 mV kG 0 55 to 1 05 mV kG 6 0 to 10 0 mV kG Maximum linearity error sensitivity versus field 1 0 RDG 10 to 10 kG 1 RDG 30 to 30 kG 1 5 RDG 100 to 100 kG 0 30 RDG 10 to 10 kG 1 25 RDG 30 to 30 kG Zero field offset voltage IC nominal control current 100 µV max 50 µV max 75 µV max Operating temperature range 40 to 100 ...

Page 92: ...Type 0 F3 Calibration Constant X XXX F10 Program Probe Esc Exit Program 8 At this time if any of the parameters need to be changed just press the appropriate F key and type in the new value When everything appears correct press F10 to program the probe 9 It takes about 20 seconds to program the probe After the probe is programmed press the Esc key to exit the program SOFTWARE LICENSE AGREEMENT Thi...

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