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Model 450 Gaussmeter User`s Manual, 2002

1. Lake Shore Cryotronics Inc henceforth Lake Shore the manufacturer warrants this product to be free from defects in material and workmanship for a period of 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 part found to be defective in material or workmanship without charge to the Owner for parts service labor or associated customary shipping cost Replacement or repaired parts will be warranted for only the unexpired portion of the original warranty or 90 days whichever is greater All products are tested and calibrated to published specifications prior to shipment Calibration Certifications are offered for 12 month periods only Where such documentation must be updated a re certification service is offered by Lake Shore at a reasonable cost LIMITATION OF WARRANTY This warranty is limited to Lake Shore products purchased and installed in the United States or Internationally through our approved distribution agents This same protection will extend to any subsequent owner during the warranty period It does not apply to damage resulting from improper or inadequate maintenance unauthorized modification or misuse or operation outside of the environmental specifications It does not apply to damage caused by accident misuse fire flood or acts of God or from failure to properly ins
2. Set Local Remote or Remote With Local Lockout Mode MODE 0 MODE 1 Or MODE 2 Nothing Sets the Model 330 mode 0 Local Mode 1 Remote Mode 2 Remote Mode with Local Lockout Press the front panel Local key to set the Model 330 to local provided the key has not been disabled by local lockout The Model 330 powers up in local mode At the end of acommand string MODE 0 maintains constant local operation Mode Query MODE Current mode setting 0 local mode 1 remote mode 2 remote mode with local lockout 4 13 TERM Input Returned Remarks TERM Input Returned Remarks Lake Shore Model 450 Gaussmeter User s Manual Set Terminating Character Type TERM 0 TERM 1 TERM 2 or TERM 3 Nothing Sets the terminating character type from 0 to 3 defined as follows 0 Carriage return and line feed CR LFEO 1 Line feed and carriage return LF CREO 2 Line feed LFFOI 3 No terminating characters EOI line set with last data byte if enabled End Terminating characters are sent when the Model 330 completes its message transfer on output They also identify the end of an input message This command works only with the IEEE 488 Interface and does not change the serial terminators Terminator Query TERM Returns the current terminating character type 0 Carriage return and line feed CRXLF 1 Line feed and carriage return LFXCR 2 Line feed LE 3 No terminating characters
3. Underwriters Laboratories UL An independent laboratory that establishes standards for commercial and industrial products unit magnetic pole A pole with a strength such that 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 volt V The difference of electric potential between two points of a conductor carrying a constant current of one ampere when the power dissipated between these points is equal to one watt volt ampere VA The SI unit of apparent power The volt ampere is the apparent power at the points of entry of a single phase two wire system when the product of the RMS value in amperes of the current by the RMS value in volts of the voltage is equal to one watt W The SI unit of power The watt is the power required to do work at the rate of 1 joule per second S weber Wb The unit of magnetic flux in the mks system equal to the magnetic flux which linking a circuit of one turn produces in it an electromotive force of 1 volt as it is reduced to zero at a uniform rate in 1 second References 1 Sybil P Parker Editor Dictionary of Scientific and Technical Terms Third Edition New York McGraw Hill 1969 IBSN 0 395 20360 0 2 Christopher J Booth Editor The New IEEE St
4. Input Returned Remarks ANOHM Input Returned Remarks ANOL Input Returned Remarks ANOL Input Returned Remarks 4 16 Lake Shore Model 450 Gaussmeter User s Manual Alarm Low Point Multiplier Query ALMLM u m k or Queries alarm low point multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Alarm Status Query ALMS oor1 Queries current alarm status 0 Off 1 On Off means no alarm condition exists On means an alarm exists Set Default Analog Out Status ANOD 0 ANOD 1 Of ANOD 2 Nothing Sets default analog output status 0 Off 1 On 2 analog output controlled by remote interface see AOCON Default Analog Out Query ANOD 0 1 0r2 Queries default analog output status 0 Off 1 On 2 analog output controlled by remote interface see AOCON Define Analog Out High Setpoint ANOH XXX XX Nothing Enter sign up to 5 digits and decimal point Place decimal appropriate to range Analog Out High Setpoint Query ANOH XXX XX Returns sign up to five digits and decimal point Places decimal appropriate to range Analog Out High Setpoint Multiplier Query ANOHM u m k or Queries analog out high setpoint multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Define Analog Out Low Setpoint ANOL XXX XX Nothing Enter sign
5. Returned Remarks xOPC Input Returned Remarks OPC Input Returned Remarks Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Common Commands Clear Interface Command CLS Nothing Clears the bits in the Status Byte Register and Standard Event Status Register and terminates all pending operations Clears the interface but not the controller The controller related command is RST Configure Status Reports in the Standard Event Status Register ESE lt bit weighting gt Nothing Each bit is assigned a bit weighting and represents the enable disable status of the corresponding event flag bit in the Standard Event Status Register To enable an event flag bit send the command ESE with the sum of the bit weighting for each desired bit See the ESR command for a list of event flags To enable event flags 0 3 4 and 7 send the command ESE 143 term 143 is the sum of the bit weighting for each bit Bit Bit Weighting Event Name 0 1 OPC 3 8 DDE 4 16 EXE 7 128 PON 143 Query the Configuration of Status Reports in the Standard Event Status Register ESE lt ESE bit weighting gt Format nnn term The integer returned represents the sum of the bit weighting of the enable bits in the Standard Event Status Enable Register Query Standard Event Status Register ESR lt ESR bit weighting gt Format nnn term Queries for various Model 450 error conditions and status The integer return
6. User s Manual Model 450 Gaussmeter EL akeShore 450 Gaussmeter AC DC Peak RMS Local Escape 7 Ps Fs Gauss Filter Tesla Address 4 51 Fe Relative Alarm Set Set Baud MIP Max Max Zero Select Auto Relative Alarm Analog Reset Hold Probe Range Range On Off On Off Out TE 9 Wi 9 Fei Fei Fee sn Enter El akeShore Lake Shore Cryotronics Inc 575 McCorkle Boulevard Westerville Ohio 43082 8888 USA E Mail Addresses sales lakeshore com service lakeshore com Visit Our Website www lakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Rev 1 5 P N 119 005 12 August 2002 Lake Shore Model 450 Gaussmeter User s Manual LIMITED WARRANTY
7. and _ Blank unity x 1 Set Relative Mode Setpoint RELS XXX XX Nothing Enter sign up to 5 digits and decimal point Place decimal appropriate to range Relative Mode Setpoint Query RELS XXX XX Returns sign up to 5 digits and decimal point Places decimal appropriate to range Relative Mode Setpoint Multiplier Query RELSM u m k or Queries relative setpoint multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 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 Remote Operation 4 21 4 3 5 FCOMP Input Returned Remarks FCOMP Input Returned Remarks SNUM Input Returned Remarks TCOMP Input Returned Remarks TCOMP Input Returned Remarks TYPE Input Returned Remarks ZCAL Input Returned Remarks 4 22 Lake Shore Model 450 Gaussmeter User s Manual Probe Specific Commands Set Field Compensation Status FCOMP 0 or FCOMP 1 Nothing Turns set field compensation On or Off 0 Off 1 On If Off probe field compensation table if present is ignored Field Compensation Query FCOMP Oorl Queries field compensation status 0 Off 1 On If Off probe field compensation table if present is ignored Probe Serial Number Quer
8. bus and instrument status and identification Common query commands end with a question mark Refer to Paragraph 4 3 for a list of all Model 450 common commands 4 1 2 3 Interface and Device Specific Commande Device Specific Commands are addressed commands The Model 450 supports a variety of Device Specific commands to program instruments remotely from a digital computer and to transfer measurements to the computer Most Device Specific Commands perform functions also performed from the front panel This section discusses Common and Device Specific commands Device Specific Commands consist of Interface Display Channel Control Process and Curve commands Refer to Paragraph 4 3 for a list of all Model 450 interface and device specific commands 4 2 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 1 3 Status Registers There are two status registers the Status Byte Register Paragraph 4 1 3 1 and the Standard Event Status Register Paragraph 4 1 3 2 4 1 3 1 Status Byte Register and Service Request Enable Register The Status Byte Register consists of one data byte containing six bits of information about Model 450 status STATUS BYTE REGISTER FORMAT STE A AN SA Weighting Esa 6 VE a Bit Name If the Service Request is enabled setting any of these bits causes the Model 450 to pull the SRQ management low to signal the BUS CONTROLLER These bits reset to zero upon a serial poll of the St
9. 9 Gauss Filter Tesla Address a fslfel Relative Alarm Set Set Baud MIP Max Max Zero Select Auto Relative Alarm Analo Reset Hold Probe Range Range On Off On Off Out Enter TE EE Fe Fe EA E AR dt Figure 1 1 Model 450 Gaussmeter Front Panel 450 Front bmp Introduction Lake Shore Model 450 Gaussmeter User s Manual Table 1 1 Model 450 Specifications Measurement Number of Inputs One Update Rate Five Per Second Autorange Yes Electronic DC Accuracy 0 10 of reading 0 005 of range at 25 C Drift of DC Electronics 0 02 of reading 0 003 of range C AC Frequency Range 10 to 400 Hertz Overall AC Accuracy 5 or better AC Peak Accuracy 5 typical Field Ranges Resolutions Are provided in the following three tables listed by type of probe High Stability Probe HST Tesla Resolution Resolution Range AC or DC Range AC or DC wi Filter Off PC Filter On wi Filter Off PC Filter On 0 01 KG 0 001 T 0 001 kG 0 0001 T 0 0001 kG 0 01 mT 0 01 G 0 001 mT High Sensitivity Probe HSE Tesla Resolution Resolution Range AC or DC F Range AC or DC P wi Filter off PC Filter On wi Filter Off PC Filter On 0 001 kG 0 0001 T 0 0001 kG 0 01 mT 0 01 G 0 001 mT 0 001 G 0 0001 mT Ultra High Sensitivity Probe UHS Resolution Range AC or DC 8 Range AC or DC E wi Filter Off DC Filter On wi Filter Off DC Filter On 0 001 G 0 0
10. Device signal levels will be 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 C 3 CAUTION The four Hall generator leads connect to four points on a sheet of semiconductor material having different potentials No two leads can be connected together without adversely affecting operation Therefore the current source and the output indicator cannot have a common connection but must be isolated from each other One the other but not both may be grounded CAUTION 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 the current supply must be isolated from the output display or the down stream electronics Hall Generator C 3 C4 0 C 4 Lake Shore Model 450 Gaussmeter User s Manual Hall Generator Model 120CS WU Current Source Digital Voltmeter Load resistor required for optimum linearity if specified C 421 C 3 eps Figure C 3 Typical Hall Generator Hookup USING A HALL GENERATOR WITH THE MODEL 450 To hookup a Hall generator you must use a Lake Shore Model MCBL 6 Cable Assembly The cable is 200 cm 79 inches lo
11. EOI line set with last data byte if enabled End This command works only with the IEEE 488 Interface 4 3 4 Device Specific Commands ACDC Input Returned Remarks ACDC Input Returned Remarks ALARM Input Returned Remarks ALARM Input Returned Remarks 4 14 Set AC or DC Magnetic Field Reading Status ACDC OOrACDC 1 Nothing Configures the unit for AC or DC measurements 0 DC 1 AC The AC field is further defined by the PRMS Peak or RMS command AC or DC Magnetic Field Reading Query ACDC Oorl Queries current AC or DC measurement status 0 DC 1 AC The AC field is further defined by the PRMS Peak or RMS command Set Alarm Function On Off ALARM 0 Or ALARM 1 Nothing Sets the alarm function 0 Off 1 On Alarm Query ALARM Dor L Queries unit for alarm function 0 Off 1 On Remote Operation ALMB Input Returned Remarks ALMB Input Returned Remarks ALMH Input Returned Remarks ALMH Input Returned Remarks ALMHM Input Returned Remarks ALMIO Input Returned Remarks ALMIO Input Returned Remarks ALML Input Returned Remarks ALML Input Returned Remarks Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Set Audible Alarm Status ALMB 0 or ALMB 1 Nothing Sets the audible alarm status 0 Off 1 On Audible Alarm Query ALMB Dor L Queries
12. Features 10 volt corrected analog output 5 2 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 5 11 4002 RJ 11 to DB 25 Adapter Adapts RJ 11 receptacle to female DB 25 connector Connects Model 450 to RS 232C Serial Port on rear of Customer s computer See Figure 5 12 4003 RJ 11 to DE 9 Adapter Adapts RJ 11 receptacle to female DE 9 connector Connects Model 450 to RS 232C Serial Port on rear of Customer s computer See Figure 5 13 4004 IEEE 488 Interface Cable Connects Model 450 to customer supplied computer with IEEE 488 Interface Cable is 1 meter 3 3 feet long 4022 Half Rack Mounting Kit for One 1 2 Rack Gaussmeter Half length mounting panel and mounting ears to attach one Model 450 Gaussmeter to a 482 6 mm 19 inch rack mount space See Figure 5 14 4026 Dual Mounting Shelf for Two 1 2 Rack Gaussmeters Mounting panel and mounting ears to attach two Model 450 Gaussmeters to a 482 6 mm 19 inch rack mount space See Figure 5 15 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 5 9 4065 Large Ze
13. Installation 2 1 Lake Shore Model 450 Gaussmeter User s Manual 2 3 DEFINITION OF REAR PANEL CONNECTIONS 2 2 The Model 450 rear panel consists of the power and fuse assembly IEEE 488 Interface Connector Serial UO Connector Corrected and Monitor Analog Output BNCs and a DA 15 Probe Input Connector See Figure 2 1 Refer to Chapter 5 for rear panel connector pin out details WARNING NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO TRAINED SERVICE PERSONNEL ANALOG OUTPUTS Bi aen mt Ce Corrected Monitor 6 PROBE INPUT E Y en H AF g IEEE 488 INTERFACE SH1 AH1 T5 L4 SR1 ALI PPODC1 DTO CO Et SERIAL VO 450 Back bmp Figure 2 1 Model 450 Rear Panel CAUTION 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 1 IEEE 488 Interface Connector The standard 24 pin connector connects the gaussmeter to any computer suitably equipped with a IEEE 488 interface Refer to Paragraph 4 1 2 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 o
14. Ittakes about 20 seconds to program the probe After the probe is programmed press the Esc key to exit the program C 8 Hall Generator
15. Model 450 Check power setting on fuse drawer window Damage may occur if connected to improper voltage 1 Check power source for proper voltage The Model 450 operates with 100 120 220 or 240 5 10 AC input voltage 2 Check fuse drawer window for proper voltage setting If incorrect refer to Paragraph 5 2 3 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 4 Plug in the DA 15 probe connector to PROBE INPUT Use thumbscrews to tighten connector to unit 5 Connect and check all other rear panel connections IEEE 488 SERIAL I O or ANALOG OUTPUTS before applying power to the unit 6 Plug line cord into receptacle Installation Lake Shore Model 450 Gaussmeter User s Manual Initial Setup And System Checkout Procedure Continued 7 Turn power switch on I The front panel display turns on and briefly displays the following message 8 The normal gaussmeter display appears similar to the following screen NOTE For best 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 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 p
16. TIMEOUT AND INSTR RS TERM 0 Wait for response INS INPUTS LOC 1 1 Get one character at a time IF INS THEN N N 1 ELSE N 0 Add 1 to timeout if no chr RS RSS INS Add next chr to string WEND Get chrs until terminators IF RS lt gt THEN See if return string is empty RSS MIDS RS 1 INSTR RS TERMS 1 Strip off terminators PRINT RESPONSE RS Print response to query ELSE PRINT NO RESPONSE No response to query END IF END IF Get next command GOTO LOOP1 Remote Operation 4 9 Lake Shore Model 450 Gaussmeter User s Manual 4 3 IEEE 488 SERIAL INTERFACE COMMAND SUMMARY There are four command groups Common Commands Paragraph 4 3 2 Interface Commands Paragraph 4 3 3 Device Specific Commands Paragraph 4 3 4 and Probe Commands Paragraph 4 3 5 Command Function Command Function Common Commands ANOLM Analog Out Low Setpoint Multiplier CLS Clear Interface AOCON Analog Output Control Mode ESE Set Std Event Status Enable AOCON Analog Output Control Mode Query ESE Query Std Event Status Enable AUTO Set Autorange Status On Off ESR Query Std Event Status Register AUTO Autorange On Off Query IDN Query Identification BRIGT Set Display Brightness Status OPC Set Operation Complete BRIGT Display Brightness Query OPC Query Operation Complete CODE Set Keyboard Lock Code RST Reset Instrument CODE Keyboard Lock Code Query SRE Set Service Request Enable FAST S
17. 3 11 BAUD To use the Serial Interface set the Baud rate Press Baud to display the screen to the right Press the A or V keys to cycle through the choices of 300 1200 or 9600 Baud Press Enter to accept the new number or Escape to keep the existing setting and return to the normal display 3 12 ANALOG OUT There are two rear panel analog outputs on the Model 450 called the Corrected and Monitor Analog Outputs Both use BNC connectors with the center conductor carrying the signal and the outer portion the ground Refer to Paragraph 3 12 1 for Corrected Analog Output and Paragraph 3 12 2 for Monitor Analog Output Operation 3 9 Lake Shore Model 450 Gaussmeter User s Manual 3 12 1 Corrected Analog Out The Corrected Analog Output is a DC value proportional to the displayed field The displayed field reading may be corrected for probe nonlinearity zero offset and temperature This output is not a real time signal but updates at the same rate as the display The standard Model 450 has a Corrected output where 3 volts equals full scale for the selected range The Model 450 10 features a modified Corrected Analog Output where 10 volts equals full scale for the selected range The examples in this section assume the standard 3 volt setting For the example below the 3 KG range was selected i 0 KG R 3 KG 2 KG 1 KG 1 KG 2 KG 3 KG eine 3 V 2V 1V po 1V 2 V 3 V To select the default range press the Analog Out ke
18. 3 7 Gauss Mi E ad rn en ta de 3 6 3 8 Relative Set and Relative On Off oooooocccococccococononococcnncnonnononoconnnnnnnnnnnnnncnnnnnnnnnnn nn nn nnncnnannns 3 7 3 9 Alarm Set and Alarm On Off c cccccceeeeceeece e aaae a eaaa aaa E a aaie aaae aE 3 7 3 10 Beer Add e 3 9 3 11 Balder 3 9 3 12 Analog EE 3 9 3 12 1 Corrected Analog Dti lila 3 10 3 12 2 Monitor Analog Out nussn nereigdi ride dietten attest 3 11 3 12 3 Analog Output Control Mode oooooccccnnocccccononcccconoonnccnnnoncnnnnnoncnc canon cnc nano nn cc naar aaia 3 11 3 13 Locking and Unlocking the Keyboard ooooocococccccnnococccononoccnonononcnonono nc nr nnnn cnn rnnnn nn rnnnn rca 3 12 3 14 F ctory Default Settingsz ci dia 3 12 3 15 Probe Consid rations eege reses AC dame is 3 13 3 15 1 Changing ed tee 3 13 3 15 2 Probe Handling iii ENEE NENNEN 3 13 3 15 3 Steiere 3 14 3 15 4 Probe Accuracy Considerations oooooonnnnccnnnnoccccnnnonccnnnnorcccnn arc cnn nn rr cnn 3 15 3 16 Fast Data Mode dee edd e eaa di ibid labo 3 16 4 lt REMOTE OPERATION eem aeaa aee E a raaa E rar aE Esarp rra dende Eege gedd 4 1 4 0 EEL EE E AE E E T E EEE 4 1 4 1 IEBE488 GEA EEA AE AE E es E eee 4 1 4 1 1 Model 450 IEEE 488 Interface Settings ooooncocconnncccnonocccccononccccononcccnnnancccnanncnc nana ncncnnnns 4 1 4 1 2 IEEE 488 Interface Command Structure oooococcccoccccnccccncnnononcnnnnnnnnnnnonn nn cnn nnnnnnnnnnnnncnnnnnn 4 2 4 1 2 1 Bus Control Commandes nn nn n
19. 9 ALARM SET AND ALARM ON OFF The alarm gives an audible and visual indication when the field value is outside or inside a user specified range Two settings define alarm operating parameters First is whether the audible alarm is ON or OFF Second is whether readings inside or outside the defined field range trigger the alarm Default settings are audible alarm on and alarm triggered outside the low and high alarm setpoints To set these parameters press and hold Alarm On Off until the display to the right appears Use the A or V keys to cycle between audible alarm on or off Press Enter to accept the new value or Escape to step to the next function and retain the old setting The Model 450 proceeds to the next display Use the A or V keys to cycle between the alarm triggered inside or outside alarm setpoints Press Enter to accept the changes or Escape to exit the function and retain the old settings All alarm functions are also available over the IEEE 488 and Serial Interfaces Operation 3 7 Lake Shore Model 450 Gaussmeter User s Manual The example below details operation with the Alarm Outside setting For example with the reading centered on 1 KG the high alarm point at 1 5 KG and the low alarm point at 0 5 kG the diagram below illustrates when the alarm is ON or OFF ane Alarm el Alarm gl Off Off 3 KG 2 KG 1 kG O KG 1 KG 2 KG 3 KG Example of operation with t Low Alarm F alarm triggered by Point readings OU
20. Temp MMA 0602 TH 240 125 zl MMA 0618 TH_ 18 20 125 0 020 rs Jena MMA 1802 VH 20 063 Ge la MMA 1836 VH MMA 1808 WL 8 0 125 0 25 dia MMA 2536 WL 36 0 25 0 25 del 0 025 E S A MCA 2560 WN 60 0 50 0 005 0 005 approx pp Stainless Steel DC 10 to 400 Hz 0 25 HSE 1 to 30 KG 0 030 dia approx 0 005 per C 1 to 100 kG 2 to 100 kG Stainless Steel Figure 5 2 Definition of Lake Shore Axial Probes 1 5 K to 0 010 350 K per C C450 5 2 eps Accessories and Probes 5 5 Lake Shore Model 450 Gaussmeter User s Manual FLEXIBLE TRANSVERSE B 2 5 gt L gt Ei Es a e eo i E Ze e 0 125 0 020 Cable Length 6 6 feet 0 36 0 030 dia T This table is for L 3 inches and S 0 375 inch Corrected Temperature Coefficient Accuracy _ Operating Type of Temperature Reading Range EA Calibration 0 SH SE 0 040 Hee Lento 0 09 G C 0 015 C GC 0 025 0 125 aa 30 kG max max d Model No W Active Stem Frequency maximum Area Material Range wer sec 3E03 VG 0 005 approx 0 15 to C C HST 2 0 13 G C 0 005 C Flexible DC 10 to pre 3016 OG EES Tubing 400 Hz E 2903 VJ 0 030 HSE 1 0 50 to 0 09 G C 0 015 C eseu 085 0 020 0 dia 30 kG max max o MFT 2903 VH SES HST 2 E 0 13 G C 0 005 C This table is for
21. Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Do Not Operate In An Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes It is a safety hazard Keep Away From Live Circuits Inside the Instrument 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 Because of the danger of introducing additional hazards 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 Do Not Place Conductive Probes Against Exposed Electrical Circuits Some gaussmeter probes are equipped with conductive sheaths Keep these probes away from live electrical circuits near magnetic fields 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 Alternatin
22. a command string to confirm command execution For example CUNI K CUNI commands the Model 450 to set the temperature units to kelvin then return the temperature units to confirm the change The term free field indicates that the decimal point is a floating entity 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 450 Table 4 1 Sample BASIC IEEE 488 Interface Program IEEEEXAM BAS EXAMPLE PROGRAM FOR IEEE 488 INTERFACE This program works with QuickBasic 4 0 4 5 on an IBM PC or compatible The example requires a properly configured National Instruments GPIB PC2 card The REM INCLUDE statement is necessary along with a correct path to the file QBDECL BAS CONFIG SYS must call GPIB COM created by IBCONF EXE prior to running Basic There must be QBIB QBL library in the QuickBasic Directory and QuickBasic must start with a link to it All instrument settings are assumed to be defaults Address 12 Terminators lt CR gt lt LF gt and EOI active To use type an instrument command or query at the prompt The command transmits to the instrument and the MPS receives and displays the response If no query i
23. an accuracy of 10 15 This implies that the absolute accuracy measurement of a magnetic field is not going to reliably be better than 0 15 under the best of circumstances and more likely to be 0 20 to 0 25 29 3 B 45 13 4 6 0 3 4 e 1 5 40 04 5 0 o Error Deviation from Perpendicular 6 Effect of angular variations on percentage of reading error where Error 1 cos 0 100 C 421 3 6 eps Figure 3 6 Effect Of Angle On Measurements Operation 3 15 3 16 3 16 Lake Shore Model 450 Gaussmeter User s Manual FAST DATA MODE In normal operation the instrument updates the display computer interfaces and the corrected analog output at a rate of 5 readings per second Fast Data Mode increases the data rate when operating with either the IEEE 488 or 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 In Fast Data Mode the front panel screen displays the message below To place the instrument in Fast Data Mode use the interface command FAST 1 To leave fast data mode use this command FAST 0 To query the status of Fast Data Mode use this command FAST The unit returns 0 if Fast Data Mode is Off and 1 if On NOTE Fast Data Mode activation disables the following Model 450 functions Relative Max Hold Alarms and Autorange Temperature compensation if applicable is based on the
24. as a mass susceptibility or a molar susceptibility depending upon how M is expressed temperature scales See Kelvin Scale Celsius Scale and ITS 90 Proper metric usage requires that only kelvin and degrees Celsius be used However since degrees Fahrenheit is in such common use all three scales are delineated as follows Boiling point of water 373 15 K 100 C 212 F Triple point of water 273 16 K Freezing point of water 273 15 K 0 C 32 F Absolute zero OK 273 15 C 459 67 F kelvin Celsius Fahrenheit To convert kelvin to Celsius subtract 273 15 To convert Celsius to Fahrenheit multiply C by 1 8 then add 32 or F 1 8 x C 32 To convert Fahrenheit to Celsius subtract 32 from F then divide by 1 8 or C F 32 1 8 temperature coefficient measurement The measurement accuracy of an instrument is affected by changes in ambient temperature The error is specified as an amount of change usually in percent for every one degree change in ambient temperature tesla T The SI unit for magnetic flux density B 1 tesla 10 gauss thermal emf An electromotive force arising from a difference in temperature at two points along a circuit as in the Seebeck effect tolerance The range between allowable maximum and minimum values turns N One complete loop of wire In the Model 480 the turns of a coil must be entered to perform flux measurements in units of Volt seconds V so Webers Wb or Maxwells Mx
25. cgs unit for the magnetic field strength H 1 oersted 10 4r ampere meter 79 58 ampere meter ohm Q The SI unit of resistance and of impedance The ohm is the resistance of a conductor such that a constant current of one ampere in it produces a voltage of one volt between je ends pascal Pa The SI unit of pressure equal to 1 N m Equal to 1 45x10 psi 1 0197x10 kgr lem 7 5x10 torr 4 191x10 inches of water or 1x10 bar A 4 Glossary of Terminology Lake Shore Model 450 Gaussmeter User s Manual permeability Material parameter which is the ratio of the magnetic induction B to the magnetic field strength H u B H Also see Initial Permeability and Differential Permeability polynomial fit A mathematical equation used to fit calibration data Polynomials are constructed of finite sums of terms of the form a where a is the i fit coefficient and x is some function of the dependent variable pounds per square inch psi A unit of pressure 1 psi 6 89473 kPa Variations include psi absolute psia measured relative to vacuum Zero pressure where one atmosphere pressure equals 14 696 psia and psi gauge psig where gauge measured relative to atmospheric or some other reference pressure ppm Parts per million e g 4 x 10 is four parts per million precision Careful measurement under controlled conditions which can be repeated with similar results See repeatability Also means that small differences
26. current audible alarm status 0 Off 1 On Set Alarm High Point ALMH XXX XX Nothing Enter up to 5 digits with decimal point No sign required Place decimal appropriate to range Alarm High Point Query ALMH XXX XX Returns up to 5 digits with decimal point Places decimal appropriate to range Alarm High Point Multiplier Query ALMHM u m k Or _ Queries alarm high point multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Set Alarm Trigger Inside Outside Status ALMIO 0 Or ALMIO 1 Nothing Sets alarm trigger inside outside status 0 Outside 1 Inside This setting determines whether readings inside or outside the defined magnetic field range trigger the alarm Alarm Trigger Inside Outside Query ALMIO 0or1 Queries alarm trigger inside outside status 0 Outside 1 Inside This setting determines whether readings inside or outside the defined magnetic field range trigger the alarm Set Alarm Low Point ALML XXX XX Nothing Enter up to 5 digits with decimal point No sign required Place decimal appropriate to range Alarm Low Point Query ALML XXX XX Returns up to 5 digits with decimal point Places decimal appropriate to range 4 15 ALMLM Input Returned Remarks ALMS Input Returned Remarks ANOD Input Returned Remarks ANOD Input Returned Remarks ANOH Input Returned Remarks ANOH
27. exchange DDE A method of interprocess communication which passes data between processes and synchronized events DDE uses shared memory to exchange data between applications and a protocol to synchronize the passing of data dynamic link library DLL A module that contains code data and Windows resources that multiple Windows programs can access electromagnet A device in which a magnetic field is generated as the result of electrical current passing through a helical conducting coil It can be configured as an iron free solenoid in which the field is produced along the axis of the coil or an iron cored structure in which the field is produced in an air gap between pole faces The coil can be water cooled copper or aluminum or superconductive electron An elementary particle containing the smallest negative electric charge Note The mass of the electron is approximately equal to 1 1837 of the mass of the hydrogen atom electrostatic discharge ESD A transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field error Any discrepancy between a computed observed or measured quantity and the true specified or theoretically correct value or condition Fahrenheit F Scale A temperature scale that registers the freezing point of water as 32 F and the boiling point as 212 F under normal atmospheric pressure See Temperature for conversions fl
28. for the laboratory It features e Field Measurement High Accuracy with High Resolution Auto Range DC or AC Field Measurement Individual Linearization of Hall Probes Temperature Compensation of Hall Probes certain models only Alphanumeric Display 4 digit 1 Part In 30 000 Resolution On All Ranges 5 digit with DC and Filter 1 Part In 300 000 Resolution 2 Line by 20 Character Vacuum Fluorescent Display e Other Major Operating Functions Display Filter Gauss or Tesla Units Max Hold Relative Reading Audible Alarm for High and Low Field e Interface IEEE 488 2 Interface Serial Interface RS 232C Electrical Format Corrected and Monitor Analog Outputs Fast Data Acquisition Mode 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 e Software Available LabVIEW Driver Available We welcome comments concerning this manual Although every effort has been made to keep it free from errors 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 Ohio 43082 8888 The material in this
29. high sensitivity probes also feature Gelle EE E EES Compensation OFF causes the Model 450 to ignore this data Press the A or Y keys to cycle between ON and OFF Push Enter to accept the new setting or Escape to retain the old setting and return to the normal display Ifthe probe has no temperature compensation the setting is ignored 3 7 GAUSS TESLA The Model 450 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 450 displays AC or DC field values followed by T for tesla mT for millitesla or UT for microtesla and formats field values over the IEEE 488 Serial Interface accordingly When gauss is selected the Model 450 displays AC or DC field values followed by KG for kilogauss G for gauss or MG for milligauss and formats field values over the IEEE 488 Serial Interface accordingly 3 6 Operation Lake Shore Model 450 Gaussmeter User s Manual 3 8 RELATIVE SET AND RELATIVE ON OFF The relative function lets the user see small variations in larger fields Set the setpoint or center of the relative reading with Relative Set There are two ways to enter t
30. k Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 47M Multiply a number in Gaussian units by C to convert it to SI e g 1 G x 10 T G 10 T SI Syst me International d Unit s has been adopted by the National Bureau of Standards Where two conversion factors are given the upper one is recognized under or consistent with SI and is based on the definition B Uo H M where to po 47 x 107H m The lower one is not recognized under SI and is based on the definition B uH J where the symbol I is often used in place of J 1 gauss 10 gamma y Both oersted and gauss are expressed as cm geg in terms of base units A m was often expressed as ampere turn per meter when used for magnetic field strength Magnetic moment per unit volume The designation emu is not a unit Recognized under SI even though based on the definition B uH J See footnote c Ur H Mo 1 x all in SI pris equal to Gaussian p B Hand uM H have SI units J m M H and B H 4r have Gaussian units erg cm R B Goldfarb and F R Fickett U S Department of Commerce National Bureau of Standards Bolder Colorado 80303 March 1985 NBS Special Publication 696 For sale by the Superintendent of Documents U S Government Printing Office Washington D C 20402 Units for Magnetic Properties B 1 Lake Shore Model 450 Gaussmeter User s Manual Table B 2 Recommended SI Values for Physic
31. larger fields The user defined setpoint becomes the center or zero point of the relative reading and is shown on the lower line of the display The difference from the setpoint or the relative reading appears in the top display with a A symbol Corrected and Monitor analog outputs provide high accuracy and waveform monitoring The Corrected Analog Output is a DC voltage proportional to the reading displayed on the front panel A default voltage range of 10 volts or 3 volts for full scale field can be selected or the voltage range can be customized using the Analog Out function on the keypad The Monitor Analog Output is a real time analog signal proportional to the magnetic field The scale of the Monitor Analog Output is 3 volts for full scale of selected range The Monitor Analog Output is not as accurate as the Corrected Analog Output but it has the full DC to 400 Hz bandwidth The Monitor Analog Output allows the user to observe the actual magnetic field waveform on an oscilloscope A Fast Data Acquisition Mode is included that shuts down the front panel display and provides up to 18 field readings per second over the IEEE 488 Interface In addition the Serial interface at 9600 Baud can return 15 readings per second Fast data mode is activated by issuing a FAST command using one of the remote interfaces then using the FIELD command to return a string of data El akeShor e 450 Gaussmeter AC DC Peak RMS Local Escape i 8
32. magnet The calibration point is the largest reading in the midpoint area lts amplitude will be approximately twice that of the readings that occur where the probe enters or leaves the magnet 4 7 cm dia 1 845 gt 4 cm 1 56 2 9 cm 1 13 0 32 d a min gap Transverse 0 062 gap MRT 062 200 within 1 of nominal value MRT 062 500 within 1 of nominal value MRT 062 1K within 0 5 of nominal value MRT 062 2K within 0 5 of nominal value MRT 062 5K within 0 5 of nominal value Center line of magnet is center of gap Transverse 0 062 gap MRT 062 10K within 0 5 of nominal value working space Axial 0 312 diameter working space MRA 312 2K within 1 of nominal value MRA 312 1K within 1 of nominal value 3 96cm 1 56 O D 0 79 cm 0 31 d a min working space 5 6 cm 2 191 Axial 0 312 diameter working space MRA 312 100 within 1 of nominal value MRA 312 200 within 1 of nominal value MRA 312 500 within 1 of nominal value P 450 5 8 bmp Figure 5 8 Lake Shore Reference Magnets Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual NOTE Use care to ensure the Zero Gauss Chamber does not become magnetized Using a magnetized chamber to zero a probe can lead to erroneous field readings It is a good practice to periodically degauss the chamber If no professional degausser is available a bulk tape degausser Radio Shack P N 44 232 or equivalent may be u
33. manual is subject to change without notice Introduction 1 1 1 1 Lake Shore Model 450 Gaussmeter User s Manual MODEL 450 GAUSSMETER SYSTEM DESCRIPTION The Model 450 is an extremely accurate full featured gaussmeter The Model 450 covers a wide range of magnetic fields and applications The instrument provides easy to use front panel programming and a vacuum fluorescent alphanumeric display This alphanumeric format allows for message based front panel operation Most operations can be performed and monitored through the front panel keypad and message display A list of specifications is provided in Table 1 1 The Model 450 measures fields in either gauss G or tesla T Set magnetic field ranges manually or with auto ranging The gaussmeter measures both DC and AC magnetic field values In DC operation the display shows the DC field at the probe with the sign orientation followed by the appropriate field units In AC operation the display shows a Peak or RMS value for the field at the probe The Max Hold function captures and displays the largest field magnitude seen since the last Max Reset The maximum value is shown 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 In AC Peak the Max Hold feature displays the magnitude of the peak value of a non periodic waveform The relative function lets the user see small variations in
34. unable to interpret a command due to syntax error unrecognized header or terminators or unsupported command Execution Error EXE Bit 4 Set to indicate an execution error This occurs when the controller is instructed to do something not within its capabilities Device Dependent Error DDE Bit 3 Set to indicate a device dependent error Determine the actual device dependent error by executing the various device dependent queries Query Error QYE Bit 2 Set to indicate a query error Occurs rarely but involves data loss due to full output queue Operation Complete OPC Bit 0 This bit is generated in response to the OPC common command It indicates when the Model 450 has completed all selected pending operations 4 1 4 Example IEEE Setup and Program Below is an example of how to setup and run a simple program using the built in Model 450 IEEE 488 Interface It does not reflect every hardware software configuration found in the field This example uses the National Instruments GPIB PCII IIA card and QuickBasic 4 0 or 4 5 on a PC compatible 4 1 4 1 GPIB Board Installation Install GPIB PCII IIA card using National Instruments instructions Install NI 488 2 software for DOS Version 2 1 1 was used for the example Verify that config sys contains the command device gpib pc gpib com Reboot the computer Run IBTEST to test software configuration Do nat install the instrument before running IBTEST R
35. units G gauss T tesla G ENTER COMMAND ACDC AC or DC Query Unit returns appropriate setting 0 DC 1 AC 0 ENTER COMMAND FILT Filter Query Unit returns appropriate setting 0 Off 1 On 0 ENTER COMMAND FILT 1 FILT Unit turns the filter On then returns a 1 to verify the change T ENTER COMMAND 4 8 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 2 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 Adda query to the end of a command string to confirm command execution For example UNIT G UNIT commands the Model 450 to set units to gauss then requests the Model 450 return the units to confirm the change A correctly spelled query without a 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 e Leading zeros and zeros following a decimal point are unneeded in a command string but they are sent in response to a query A leading is not required but a leading is required e term indicates where the user places terminating characters or where they appear on a returning charact
36. 0 front panel keyboard may be locked preventing unauthorized changes to the settings To lock the keyboard press and hold Enter about 10 seconds until the following display appears Enter the 3 digit lock code the default is 123 Upon entry of the third number the display reverts to the normal display The keyboard is now locked After locking the keypad any attempt to change settings displays the following Locked message To unlock the keyboard press and hold the Enter key until the following message is displayed Enter the lock code again Upon entry of the third number the display reverts to the normal display and the keyboard is unlocked Change the lock code using either the IEEE 488 or RS 232C Computer Interface For future reference record the lock code for your installation If the instrument is reset Paragraph 3 14 the lock code reverts to 123 The instrument cannot be reset when the keyboard is locked 3 14 FACTORY DEFAULT SETTINGS With the keypad unlocked and the Model 450 in local mode the user may press and hold Escape for about 20 seconds to return the instrument to factory default settings AC DC DC Filter Number 8 Address 12 Filter Window 1 Alarm Off Gauss Tesla Gauss Alarm Trigger Outside Keypad Not Locked Analog Out Default Local Remote Local Audible Alarm On Lock Code 123 Auto Range Off Max Hold Off Baud 300 Peak RMS RMS Brightness 4 Range Highest Range For Probe
37. 001 G 0 0001 mT 0 00001 mT 0 0001 G 0 00001 G 300 uT 0 01 uT 0 001 uT 300 mG 0 01 mG 0 001 mG 30 uT 0 001 uT 0 0001 uT Interfaces Audible Alarm High and Low Setpoints Corrected Analog Output Accuracy 0 1 of 3 volt or 10 volt range Monitor Analog Output Accuracy Probe Dependent IEEE 488 Capabilities Complies with IEEE 488 2 SH1 AH1 SR1 RL1 PP0 DC1 DT0 C0 E1 Serial Communication in RS 232C Electrical Format 300 1200 or 9600 Baud RJ 11 connector Fast Data Acquisition Mode Refer to Paragraph 3 16 With the IEEE 488 Interface 18 reading per second With Serial Interface at 9600 Baud 15 readings per second Introduction Lake Shore Model 450 Gaussmeter User s Manual Table 1 1 Model 450 Specifications Continued Front Panel Display Type 2 line by 20 characters vacuum fluorescent Units KG Alarm G mG Probe Orientation T DC Relative Remote DC Onl DC Only pe On On Field Reading uT RMS J Kee Lower row used for Max Hold MAX shown above and Relative um Setpoint SP readings Also used for various on off messages C 450 1 2 eps Display Resolution 4 digit 5 digit with DC amp Filter see field ranges on previous page Display Units Gauss G or tesla T 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 20 watts Size 217 mm wide x 90 mm high x 317 mm de
38. 033 4 FHMS Phillips 6 Screw 8 32 x 3 8 Inch 0 081 6 FHMS Phillips C 450 5 14 eps Figure 5 14 Model 4022 Rack Mount Kit Accessories and Probes 5 13 Lake Shore Model 450 Gaussmeter User s Manual Refer to Installation Procedure Installation Procedure 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 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 C 450 5 15 eps Figure 5 15 Model 4026 Dual Rack Mount Shelf 5 14 Accessories and Probes 6 0 6 1 6 2 Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 6 SERVICE GENERAL This chapter covers general maintenance precautions in Paragraph 6 1 electrostatic discharge in Paragraph 6 2 line voltage selection in Paragraph 6 3 fuse replacement in Paragraph 6 4 rear panel connector definitions in Paragraph 6 5 optional serial interface cable and adapters in Paragraph 6 6 operating software EPROM replacement in Paragraph 6 7 and error messages in Paragraph 6 8 There are no field serviceable parts inside the Model 450 Contact Lake Shore about specific problems with the Model 450 GENERAL MAINTENANCE PRECAUTIONS The following are general safety precautions unrelated to any other procedure in this publication Keep away from live
39. 8 32 0 0080 0 2019 3 0 2294 5 827 13 0 0720 1 829 23 0 0226 0 5733 33 0 00708 0 178 4 0 2043 5 189 14 0 0641 1 628 24 0 0207 0 5106 34 0 00630 0 152 5 0 1819 4 621 15 0 0571 1 450 25 0 0179 0 4547 35 0 00561 0 138 6 0 1620 4 115 16 0 0508 1 291 26 0 0159 0 4049 36 0 00500 0 127 7 0 1443 3 665 17 0 0453 1 150 27 0 0142 0 3606 37 0 00445 0 1131 8 0 1285 3 264 18 0 0403 1 024 28 0 0126 0 3211 38 0 00397 0 1007 9 0 1144 2 906 19 0 0359 0 9116 29 0 0113 0 2859 39 0 00353 0 08969 10 0 1019 2 588 20 0 0338 0 8118 30 0 0100 0 2546 40 0 00314 0 07987 ampere The constant current that if maintained in two straight parallel conductors of infinite length of negligible circular cross section and placed one meter apart in a vacuum would produce between these conductors a force equal to 2 x 107 newton per meter of length This is one of the base units of the SI ampere turn 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 field strength H 1 ampere meter 47 1000 oersted 0 01257 oersted analog data Data represented in a continuous form as contrasted with digital data having discrete values analog output A voltage output from an instrument that is proportional to its input From an instrument such as a digital voltmeter the output voltage is generated by a digital to analog convert
40. DE 9 Adapter Refer to Chapter 5 for Serial I O connector and adapter pin out details and Chapter 6 for adapter dimensional data Table 4 2 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 2 2 Serial Interface Settings To use the Serial Interface set the Baud rate Press Baud to display the screen to the right Press the A or V keys to cycle through the choices of 300 1200 or 9600 Baud Press Enter to accept the new number or Escape to keep the existing setting and return to the normal display 4 2 3 Sample BASIC Serial Interface Program The program in Table 4 4 is a sample interactive serial poll routine for the Model 450 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
41. Fast Data Mode Off Relative Off Field Compensation On Temperature Compensation On Filter Off Terminators CR LF Other gaussmeter calibration information and probe data are not affected by this reset Zero the probe after completing this operation 3 12 Operation Lake Shore Model 450 Gaussmeter User s Manual 3 15 PROBE CONSIDERATIONS To avoid damage and for best results during use the probes have a number of handling and accuracy requirements that must be observed Changing probes is discussed in Paragraph 3 16 1 Probe handling is discussed in Paragraph 3 16 2 Probe operation is discussed in Paragraph 3 16 3 Finally accuracy considerations are provided in Paragraph 3 16 4 3 15 1 Changing Probes A 512 byte Electrically Erasable Programmable Read Only Memory EEPROM is included in each probe The EEPROM stores specific information that the gaussmeter requires for operation The information includes serial number probe sensitivity and field compensation data CAUTION The probe must be connected to the rear of the instrument before applying power to the gaussmeter Probe memory may be erased if connected with power on When the instrument is powered up the probe memory is downloaded to the gaussmeter This is how the gaussmeter knows which ranges are available and which error correction to apply To change probes first turn power off remove the existing probe and then plug in the new probe When power is resto
42. Figure 5 4 Definition of Lake Shore Gamma Probe Accessories and Probes 5 7 Lake Shore Model 450 Gaussmeter User s Manual 5 4 HELMHOLTZ COILS 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 5 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 Strength 30G Q1A 25G 1A 12G 1A 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 3 Q 10 Q 20 Q Maximum Continuous Current 2A 10 to 40 C 50 to 104 F Oper
43. GCA 3010 DimensionS ccc ceeececeeeeeee aeons C 5 C 6 Transverse Hall Generator HGT 3010 HGT 3030 amp HGCT 3020 Dimensions c000 C 5 C 7 Axial Hall Generator HGA 2010 DIMENSIONS occccccccccccnonnconnnnoncnononononononcnonnnonnnnnononnnnnnnrnnnnnananonnnns C 6 Lake Shore Model 450 Gaussmeter User s Manual LIST OF TABLES Table No Title Page 1 1 Model 450 SpecificatiONS ooooonmiciccccnnnnnnnnononconcnncnnnnnnnonnnnnnnnnnnnnn nn nnonser nn nn nar nnnnnnnnnnnnnnnnnnnnnnnnnnnnes 1 3 4 1 Sample BASIC IEEE 488 Interface Program 4 5 4 2 Serial Interface Specifications nar nnnrnnonan rann nn nnntentrnnnnnnnnnnnnensrnnnnnnnnnnntentnnnn 4 8 4 3 Sample BASIC Serial Interface Program 4 9 C 1 Cryogenic Hall Generator Specifications ooooconnnncccnnnoniccconaccccnnnoncccnnnancccnn nn c cc nan nc cc naar nccc canaria C 5 C 2 Axial Hall Generator Specifications ooonooiccccnnnnnnnnnnocccccnnnnnnonnnonnnnnnnnnnnnnnnnnnnn a a aee aaea auai C 6 C 3 Transverse Hall Generator Specifications oooononnnncccnnnnnnnnnnoconccnnnncnonnnnnnncnncnnnnnnnnn nn nn nnnn nn ennn nnmnnn C 7 Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 1 INTRODUCTION 1 0 GENERAL This chapter provides an introduction to the Lake Shore Model 450 Gaussmeter The Model 450 was designed and manufactured in the United States of America by Lake Shore Cryotronics Inc The Model 450 is a high accuracy full featured gaussmeter ideally suited
44. L 15 inches and S 0 75 inch Corrected Operating Temperature Coefficient Model No W T a Active Stem Frequency Accuracy Temperature maximum Area Material Range of Range Reading 9 Zero Calibration D reen 150 0 045 0 150 dia g Enos DC 10 to 0 C to max max 0 050 approx POXY 400 Hz 0 15 to 75 C utse 4F15 VG Fiber HST 2 02 0 13 GPC 0 005 C glass 30 KG C450 5 3 eps Figure 5 3 Definition of Lake Shore Flexible Transverse Probes Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual GAMMA PROBE Small variations in or low values of large volume magnetic fields such as that of the i e Earth or fringe fields around large solenoids ke NS can be measured with these ultra high sensitivity probes Resolutions of several gt r Active Sensing Length W gammas 1075 gauss to tens of gammas are available depending on the mating Cable Length A 6 6 feet A gaussmeter To Center of Active Volume 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 Corrected Temperature Coefficient Accuracy Operating maximum Model No W T AJ L pr Type of Temperature ange Reading Range Calibration o o MLA 5006 HJ 0 25 0 5 2 2 5 7 DC 10 tolyys 4 05 to 0 Cto 4 mere 0 05 C 400 Hz 2 gauss 75 C C450 5 4 eps
45. Listen address 10 64 74 Talk address y F1 Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board Figure 4 1 Typical National Instruments GPIB Configuration from IBCONF EXE Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 2 SERIAL I O INTERFACE RS 232C is a standard of the Electronics Industries Association ElA and one of the most common interfaces between a computer and electronic equipment The Customer supplied computer must have a Serial Interface port The Model 450 Serial Interface complies with the electrical format of the RS 232C Interface Standard A Serial Interface between the computer and the Model 450 permits remote monitoring and control of Model 450 control functions which in turn controls Model 450 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 Refer to Paragraph 4 2 1 for Serial Interface hardware configuration and adapters Paragraph 4 2 2 for Serial Interface settings and Paragraph 4 2 3 for a sample BASIC program to establish communications between the computer and the Model 450 The Serial Interface shares Device Specific commands with the IEEE 488 interface listed in Paragrap
46. Model 450 Gaussmeter User s Manual 6 5 1 IEEE 488 INTERFACE CONNECTOR Connect to the IEEE 488 Interface connector on the Model 450 rear with cables specified in the IEEE 488 1978 standard document The cable has 24 conductors with an outer shield The connectors are 24 way Amphenol 57 Series or equivalent with piggyback receptacles to allow daisy chaining in multiple device systems The connectors are secured in the receptacles by two captive locking screws with metric threads The total length of cable allowed in a system is 2 meters for each device on the bus or 20 meters maximum A system may be composed of up to 15 devices Figure 6 5 shows the IEEE 488 Interface connector pin location and signal names as viewed from the Model 450 rear panel IEEE 488 INTERFACE SH1 AH1 T5 L4 SR1 RL1 PPO DC1 DTO CO E1 12 11 10 9 8 7 6 5 4 3 2 1 24 23 22 21 20 19 18 17 16 15 14 13 PIN SYMBOL DESCRIPTION Data Input Output Line 1 Data Input Output Line 2 Data Input Output Line 3 Data Input Output Line 4 End Or Identify Data Valid Not Ready For Data Not Data Accepted Interface Clear Service Request Attention Cable Shield Data Input Output Line 5 Data Input Output Line 6 Data Input Output Line 7 Data Input Output Line 8 Remote Enable Ground Wire Twisted pair with DAV Ground Wire Twisted pair with NRFD Ground Wire Twisted pair with NDAC Ground Wire Twisted pair with IFC Ground Wire Twisted pair with SR
47. NEE EEN ata AE de skrur 5 1 5 0 General siioni dai aat eebe rd Pil deen donee 5 1 5 1 Models Harstad 5 1 5 2 AeA E EE E A E A AA AE E A A 5 1 5 3 Lake Shore Standard Probes sste eie onae aaa ee a aaa aaa e E aeaea 5 3 5 3 1 Probe Selection Criteria nar nnnnnnnnnn rann nn nnnnnnennnnnnnnnnnnnennnnnnnnne 5 3 5 3 2 Radiation Effects on Gaussmeter Probes oooooocccccccncncocononcconcnncnnnnononncnnnnnnnnnnonnnnnnnnnnnnnnes 5 3 5 3 3 Probe Specifications att deel brakk 5 4 5 4 eil Le ee EE 5 8 5 5 Reference Magnet 2 mmmmmminitnvaredvinsandridne ned b e bd 5 10 6 SERVICE init ATA 6 1 6 0 A ab knes dene eee 6 1 6 1 General Maintenance Precautions ooooccocccncccocococcconccnnnnnnononncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnrninnnnnes 6 1 6 2 Electrostatic Discharge voii dd 6 1 6 2 1 Identification of Electrostatic Discharge Sensitive Components rnrarsrrnnnnnvvrnnnnnnvrnnnnnr 6 2 6 2 2 Handling of Electrostatic Discharge Sensitive Components nnarsnrnnnnnvvrnnnnnvvrnnnnrnrnnnnn 6 2 6 3 Line Voltage Selection ocio lada ii dd dida 6 2 6 4 Fuse Replacement eserita a aa S 6 3 6 5 Rear Panel Connector Definitions nn nn cn nnnnnnnnnrrnnncnn 6 4 6 5 1 IEEE 488 Interface Connector z pactio aaa e e a aaa aa aaa aaa a aa 6 5 6 6 Optional Serial Interface Cable and Adapters ooooocinicococccnnccococonononnnnncnnnnnnnonnnnnnnnnnanannnnnos 6 6 6 7 Operating Software EPROM Replacement cccccccceceeeeeeeeeeneeceeeeeeeseeenc
48. Psi y Y Theta 0 e Pi T I Omega o Q ground A conducting connection whether intentional or accidental by which an electric circuit or equipment is connected to the earth or to some conducting body of large extent that serves in place of the earth Note It is used for establishing and maintaining the potential of the earth or of the conducting body or approximately that potential on conductors connected to it and for conducting ground current to and from the earth or of the conducting body H Symbol for magnetic field strength See Magnetic Field Strength Hall effect The generation of an electric potential perpendicular to both an electric current flowing along a thin conducting material and an external magnetic field applied at right angles to the current Named for Edwin H Hall 1855 1938 an American physicist Hall mobility The quantity uH in the relation UH Ro where R Hall coefficient and o conductivity Helmholtz coils A pair of flat circular coils having equal numbers of turns and equal diameters arranged with a common axis and connected in series used to obtain a magnetic field more nearly uniform than that of a single coil hertz Hz A unit of frequency equal to one cycle per second hole A mobile vacancy in the electronic valence structure of a semiconductor that acts like a positive electron charge with a positive mass hysteresis The dependence of the state of a system on its previous history general
49. Q Ground Wire Twisted pair with ATN Logic Ground C450 6 5 eps OO JO Om P Go Figure 6 5 IEEE 488 Rear Panel Connector Details Service 6 5 Lake Shore Model 450 Gaussmeter User s Manual 6 6 OPTIONAL SERIAL INTERFACE CABLE AND ADAPTERS To aid in Serial Interface troubleshooting Figures 6 6 thru 6 8 show wiring information for the optional cable assembly and the two mating adapters TxD YELLOW Gnd GREEN Gnd RED RxD BLACK Figure 6 6 Model 2001 RJ 11 Cable Assembly Wiring Details 123456 95 vez CONNECTOR O 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 RJ11 RECEPTACLE DB9 CONNECTOR NOT USED For Customer supplied computer with DE 9 Serial Interface Connector configured as DTE If the interface is DCE a Null Modem Adapter is required to exchange Transmit and Receive lines RJ11 RECEPTACLE Figure 6 8 Model 2003 RJ 11 to DE 9 Adapter Wiring Details 6 6 Service Lake Shore Model 450 Gaussmeter User s Manual 6 7 OPERATING SOFTWARE EPROM REPLACEMENT The operating software for the Model 450 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 labe
50. TSIDE user defined setpoints High Alarm Point To enter this alarm setup push Alarm Set The unit prompts for the High Alarm Point The initial range displayed is the same as the latest probe range To set an alarm in a different range push Select Range until the proper range displays Then use the numeric keypad to enter the high alarm point After entering the desired high alarm point press Enter to accept the new value or Escape to retain the old value The display proceeds to the Low Alarm Point The initial range displayed is the same as the latest probe range To set an alarm in a different range push Select Range until the proper range displays Then use the numeric keypad to enter the low alarm point After entering the desired alarm point press Enter to accept the new value or Escape to retain the old value The alarm setpoints are absolute unsigned i e only the magnitude of the field reading is used After entering proper high and low alarm points press Alarm On Off to activate the alarm The message Alarm On appears on the lower line of the display and the musical note appears in the upper right hand corner of the display signifying alarm ON When the field reading is outside the alarm setpoints the musical note flashes and if turned ON the alarm sounds To turn the alarm OFF press Alarm On Off again The message Alarm Off appears The example below details how the alarm operates on the Insi
51. abvolt in a circuit of one turn link the flux as the flux is reduced to zero in 1 second at a uniform rate MKSA System of Units A system in which the basic units are the meter kilogram and second and the ampere is a derived unit defined by assigning the magnitude 47 x 107 to the rationalized magnetic constant sometimes called the permeability of space NBS National Bureau of Standards Now referred to as NIST National Institute of Standards and Technology NIST Government agency located in Gaithersburg Maryland and Boulder Colorado that defines measurement standards in the United States See Standards Laboratories for an international listing noise electrical Unwanted electrical signals that produce undesirable effects in circuits of control systems in which they occur normalized sensitivity For resistors signal sensitivity dR dT is geometry dependent i e dR dT scales directly with R consequently very often this sensitivity is normalized by dividing by the measured resistance to give a sensitivity sr in percent change per kelvin st 100 R dR dT K where T is temperature in kelvin and R is resistance in ohms normally closed N C A term used for switches and relay contacts Provides a closed circuit when actuator is in the free unenergized position normally open N O A term used for switches and relay contacts Provides an open circuit when actuator is in the free unenergized position oersted Oe The
52. aeeeeeeeeeseesnaeess 6 7 APPENDIX A GLOSSARY OF TERMINOLOGY rrnnnnnnnnnnnnvnvennnnnnnnnnnnvnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnen A 1 APPENDIX B UNITS FOR MAGNETIC PROPERTIES rannnnrnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnvnnnnnnnnnnnnnnnvnnnen B 1 APPENDIX C HALL GENERATORS mennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnen C 1 C1 0 EES seint ee eessen C 1 C2 0 Theory Operations ege deg Vodka deet age Seege de SEA edu trudde C 1 C2 1 ACTIVE Area unner adel Seege drit gs ee EEN e C 1 C2 2 Onentatlon vaske enn aan net C 2 C2 3 eut nts EE C 3 C2 4 Polar 201 NEEN neg i E a A ENEE C 3 C2 5 Lead Configurations rana e REA aT A E A AET ER EA AEA AR C 3 C3 0 Hall Generator Generic Hookup ran nnnnnnnnnnnn nar nnnennenrnnn nn nnnnneenenrnnnnnnnnnn C 3 C4 0 Using a Hall Generator with the Model A0 C 4 C5 0 elle ere EE C 5 C6 0 HALE CAL EXE Program ungarere eksen eege bar ker irer C 8 Lake Shore Model 450 Gaussmeter User s Manual LIST OF ILLUSTRATIONS Figure No Title Page 1 1 Model 450 Gaussmeter Front Panel 1 2 2 1 Model 450 Rear Panel ME 2 1 2 2 Line Input Assemblyruanskuuisen rige ta 2 3 2 3 Model MCBL 6 User Programmable Cable ACcessonm nc canon nn ccnnnnnccnnnns 2 4 3 1 Model 450 Front Panel iconos ii danene he Sal Ee 3 1 3 2 Front Panel Display Definitia canon cnc canon cnc naar nc deaa A 3 3 3 3 Display Filter Response Examples ccccccsee
53. age 50 60 Hz 40 VA MAX FUSE DATA 100 120 V 05A 0 25 x 1 25 In T 220 240 V 0 25 A 5x 20mm I 450_Power bmp Figure 2 2 Line Input Assembly PROBE INPUT CONNECTION WARNING Some probes used with the gaussmeter have conductive parts Never probe near exposed live voltage Personal injury and damage to the instrument may result CAUTION Always turn off the instrument before making any rear panel Probe Input connections The Lake Shore probe plugs into the 15 pin D style connector on the rear panel Turn the instrument off before attaching the probe Align the probe connector with the rear panel connector and push straight in to avoid bending the 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 Refer to Paragraph 3 15 for additional probe considerations When power is turned on the instrument reads parameters from probe memory The probe is ready to use No parameters need to be entered into the Model 450 However the Zero Probe function should be performed the first time a probe is used with the instrument and periodically during use Installation 2 3 Lake Shore Model 450 Gaussmeter User s Manual 2 5 1 2 6 2 7 2 4 Attachment To A Hall Generator The Model MCBL 6 has a 15 pin D Style connector on one end for direct attachment to the PROBE INPUT connection on the back panel of the Model 450 Gaussmeter F
54. age drop due to lead resistance in series with the gaussmeter input The Lake Shore Hall generator sensitivity given on the data sheet is basically with no lead resistance See Figure C 4 The gaussmeter needs input sensitivity between 0 5 to 1 5 mV kG HST or R 5 0 and 15 mV KG HSE at its input cable Roust Hall Generator Open Circuit Sensitivity Gaussmeter Input Reable Roust Sensitivity at Gaussmeter input is 8 R Lake Shore Model R Customer reduced by the lead input voltage divider cable E y SE Se MCBL 6 Cable Assembly Supplied Leads C 421 C 4 eps Figure C 4 Hall Generator Input Impedance Hall Generator Lake Shore Model 450 Gaussmeter User s Manual C5 0 SPECIFICATIONS This section covers three types of Hall generators available from Lake Shore HGCA amp HGCT Series Cryogenic Hall generators Figures C 5 and C 6 with specifications Table C 1 HGA Series Axial Hall generators Figures C 5 and C 7 with specifications Table C 2 and HGT Series Transverse Hall generators Figures C 8 thru C 10 with specifications Table C 3 0 25 in 9 5 in PR 0 20 EE min 2 ODD ea gt DIXIE B Zen las er in diameter C 421 C 5 eps Figure C 5 Axial Hall Generator HGA 3010 HGA 3030 and HGCA 3020 Dimensions 0 63 in 9 5 in min 0 180 in Lead Length 0 240 in ZA max B SPE Center of rotective i Active Area 0 043 in max Ceramic Case C 421 C 6 e
55. agraph 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 press Zero Probe then Enter Refer to Paragraph 3 3 Select Range Manually selects field measurement range Available ranges depend on which probe is installed Refer to Paragraph 3 4 Auto Range Turns Auto Range feature ON and OFF Allows the Model 450 to automatically select field measurement range Refer to Paragraph 3 4 ACIDC Selects periodic AC or static DC magnetic fields The AC selection provides the option of Peak or RMS readings Refer to Paragraph 3 5 Peak RMS The AC selection provides the option of Peak or Root Mean Square RMS readings Also use Peak with the Max Hold feature to measure single peaks Refer to Paragraph 3 5 Ta Ell akeShore 450 Gaussmeter AC DC Peak RMS Local Escape Fl Pal E Gauss i Filter Tesla Address 4 5 Pel Pal Relative Alarm Set Set Baud 1 2 3 v Max Max Zero Select Auto Relative Alarm Analog Reset Hold Probe Range Range On Off On Off Out Enter Si S PIP FAN 450 Front bmp Figure 3 1 Model 450 Front Panel Operation 3 1 Lake Shore Model 450 Gaussmeter User s Manual Front Panel Keypad Definitions Continued Filter Turns filter ON or OFF and configures filter Filter ON enables high resolution DC readings Press and hold Filter to select Field Compensation and Temperature Compensation ON o
56. al Constants pera ven me terte 0 0073 Fine Structure Constant u0ce2 2h m 137 0360 Elementary Charge AE DE a N 1 6022x10 C l 6 6262 x 10 J Hz Plank Constant pene 1 0546 x 10 J s Avogadro s Constant 6 0220 x 10 mor Atomic Mass Unit lu 10 kg mol NA 1 6605 x 10 kg 0 9109 x 10 kg Electron Rest Mass 5 4858 x 10 u 1 6726 x 10 kg 1 6749 x 10 kg o h 2e 2 0679 x 10 Wb Magnetic Flux Quantum 4 1357 x 10 J Hz 0 Josephson Frequency Voltage Ratio 483 5939 THz V h 2me 3 6369 x 10 J Hz kg Quantum of Circulation 7 2739 x 10 J Hz C Rydberg Constant PR 1 0974x 10 mt Proton Moment in Nuclear Magnetons 2 7928 Bohr Magneton ue eh 2me 9 2741 x 10 JT Proton Gyromagnetic Ratio 2 6752 x 10 s T Diamagnetic Shielding Factor Spherical H20 Sample 1 o H20 1 0000 Molar Mass Constant PR 8 3144 J mol K Molar Volume Ideal Gas To 273 15K po 1 atm Vm RTo po 0 0224 mi mol Boltzman Constant k BIN 1 3807 x 107 J K Stefan Boltzman Constant 17 60 k E Ce 5 6703 x 10 W m K First Radiation Constant 3 7418 x 10 W m Second Radiation Constant 0 0144 mK Gravitation Constant 6 6720 x 107 N m kg Data abbreviated to 4 decimal places from CODATA Bulletin No 11 ICSU CODATA Central Office 19 Westendstrasse 6 Frankfurt Main Germany Copies of this bulletin are available from this office Units for Magnetic Properties C1 0 C2 0 C2 1 Lake Shore Model 450 Gauss
57. amber but may also be used with an open probe registering the local earth magnetic field Users wishing to cancel out large magnetic fields should use the Relative function Refer to Paragraph 3 8 Probe temperature can also affect readings Refer to the two separate temperature coefficients listed on the specification sheet The High 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 The greater the deviation from orthogonality from right angles in either of three axes the larger the error of the reading For example a 5 variance on any one axis causes a 0 4 error a 10 misalignment induces a 1 5 error etc See Figure 3 6 Tolerance of instrument probe and magnet must be considered for making critical measurements The accuracy of the gaussmeter reading is better than 0 20 of reading and 0 05 of range Absolute accuracy readings for gaussmeters and Hall probes is a difficult specification to give because all the variables of the measurement are difficult to reproduce For example a 1 error in alignment to the magnetic field causes a 0 015 reading error Finally the best probes have
58. andard Dictionary of Electrical and Electronic Terms IEEE Std 100 1992 Fifth Edition New York Institute of Electrical and Electronics Engineers 1993 IBSN 1 55937 240 0 Definitions printed with permission of the IEEE 3 Nelson Robert A Guide For Metric Practice Page BG7 8 Physics Today Eleventh Annual Buyer s Guide August 1994 ISSN 0031 9228 coden PHTOAD A 6 Glossary of Terminology Magnetic flux density Magnetic induction Magnetic Flux magnetomotive force Magnetic field strength magnetizing force Volume magnetization Volume magnetization Ach 10 47 A Magnetic polarization Lake Shore Model 450 Gaussmeter User s Manual APPENDIX B UNITS FOR MAGNETIC PROPERTIES Conversion from CGS to SI Units Quantit Gaussian Conversion SI amp 3 amp CGS emu Factor C Rationalized mks VARER E weber Wb volt F gilbert Gb 10 47 ampere A oersted Oe Gb cm 107 41 A Al 3 H M 3 intensity of magnetization Se Se 1 A m kg i o M emu a m emu erg G 103 Asia joule per Magnetic dipole moment Volume susceptibility Wbm k dimensionless BS a Henry per meter X emu cm 47 x 10 H m Wb A m 3 6 3 Permeability Relative permeability Volume energy density Demagnetization factor D J H Him Wb A m Ur not defined dimensionless W erg cm 10 Jim N dimensionless dimensionless k energy product NOTES a b C j
59. anges and block noise The filter also quiets noise within the instrument by adding a digit of usable resolution in DC To turn ON the display filter press Filter to display the screen to the right Press Filter or the A or Y keys to toggle between ON and OFF Press Enter to accept the new setting or Escape to retain the old setting and return to the normal display With Filter turned on two additional displays appear the Filter Points display and the Filter Window display The Filter Points display sets the number of points to use in the filter algorithm Enter from 2 to 64 points 8 is the default The unit takes one point each display update cycle so filter settling time depends on update speed and number of samples The Filter Window display sets a limit for restarting the filter If a single field reading differs from the filter value by more than the limit specified the instrument assumes an intentional change and restarts the filter at the new reading value This allows faster instrument response to changing fields than if the filter functioned continually Enter settings from 1 to 10 1 is the default Operation 3 5 The Model 450 uses two different filter algorithms that result in slightly different settling time computations For 2 to 8 filter points a linear average is used for the fastest response In this case the filter settles in the same number of samples as entered For example when set at 8 points and
60. arrier 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 Refer to the standard Lake Shore Warranty on the A Page immediately behind the title page REPACKAGING FOR SHIPMENT To return the Model 450 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 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 1 Instrument model and serial number 2 User name company address and phone number 3 Malfunction symptoms 4 Description of system 5 Returned Goods Authorization RGA number Wrap instrument in a protective bag and use original spacers to protect controls Repack the system in the Lake Shore 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
61. ata Mode which obtains data rates up to 18 readings per second via IEEE 488 or 15 readings per second via Serial Interface with a corresponding increase in corrected analog output The front panel display does not function in this mode Refer to Paragraph 3 16 Fast Data Mode Status Query FAST 0or1 Queries Fast Data Mode status 0 Off 1 On Obtains data rates up to 18 readings per second via IEEE 488 or 15 readings per second via the Serial Interface with a corresponding increase in corrected analog output The front panel display does not function in this mode Refer to Paragraph 3 16 Present Magnetic Field Reading FIELD XXX XX Returns sign six numbers if the filter is on five numbers if the filter is off and decimal point Places decimal appropriate to range Requires MULT and UNITS commands to fully define the reading Field Reading Multiplier Query FIELDM u m k Or _ Queries field reading multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Set Display Filter Status FILT 0orFILT 1 Nothing Turns display filter On or Off 0 Off 1 On Quiets the display reading by a degree depending on the points FNUM and window FWIN settings Refer to Paragraph 3 6 1 Display Filter Query FILT oor1 Queries display filter status 0 Off 1 On Quiets the display reading by a degree depending on the points FNUM and window FWIN settings R
62. ating Temperature Range 1 25 WIDE 1 00 HIGH OPENING THRU BOTH SIDES BANANA JACKS CURRENT INPUT P 450 5 5 bmp Figure 5 5 Model MH 2 5 Helmholtz Coil 5 8 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual 233 Banana Jacks Input E e 3 5 b Leg 5 4 ees P 450 5 6 bmp P 450 5 7 bmp Figure 5 7 Model MH 12 Helmholtz Coil Accessories and Probes 5 9 Lake Shore Model 450 Gaussmeter User s Manual 5 5 5 10 REFERENCE MAGNETS Magnetic reference standards containing highly stable permanent magnets have been in use for many years The highest quality units are usually shielded from external magnetic effects and use Alnico V or VI magnets for long term stability They are supplied in both transverse flat and axial configurations Typical transverse reference magnets are usually stabilized for use at ambient temperatures between 0 50 C and have nominal temperature coefficients of about 0 02 C Because the temperature coefficient is negative the field strength will be reduced as the temperature rises Since these references are temperature cycled during manufacture their change with temperature is predictable and retraceable they will always return to a known value at any specific ambient temperature The high permeability shell which surrounds the reference magnet serves two function 1 it shields the magnet from ex
63. atus Byte Register Inhibit or enable these reports by turning their corresponding bits off or on in the Service Request Enable Register The SRE command sets the bits Setting a bit in the Service Request Enable Register enables that function Refer to the SRE command Service Request SRQ Bit 6 Determines whether the Model 450 reports via the SRQ line Four bits determine which status reports to make If bits 0 1 2 4 and or 5 are set then the corresponding bit in the Status Byte Register is set The Model 450 produces a service request only if bit 6 of the Service Request Enable Register is set If disabled the BUS CONTROLLER still examines Status Byte Register status reports by serial poll SPE but the Service Request cannot interrupt the BUS CONTROLLER The STB common command reads the Status Byte Register but will not clear the bits The Status Byte Register bit assignments are described below These reports occur only if enabled in the Service Request Enable Register Field Data Ready FDR Bit 0 When set new valid field readings are available Range Change RNG Bit 1 Range changed in Auto Range mode on any channel Alarm ALM Bit 2 When set an alarm condition exists on any channel This condition latches until acknowledged by the bus controller Overload Indicator OVI Bit 4 When set indicates a display overload on any selected channel Issues a Service Request if enabled Standard Event Sta
64. can be detected and measured with confidence See resolution prefixes Sl prefixes used throughout this manual are as follows Factor Prefix Symbol Factor Prefix Symbol 10 yotta Y 101 deci d 1021 zetta Z 102 centi c 1018 exa E 103 milli m 1015 peta P 10 micro u 1012 tera T 102 nano n 109 giga G 10 12 pico p 106 mega M 10 15 femto f 103 kilo k 10 18 atto a 102 hecto h 10 21 zepto E 101 deka da 10 yocto y probe A long thin body containing a sensing element which can be inserted into a system in order to make measurements Typically the measurement is localized to the region near the tip of the probe remanence The remaining magnetic induction in a magnetic material when the material is first saturated and then the applied field is reduced to zero The remanence would be the upper limit to values for the remanent induction Note that no strict convention exists for the use of remanent induction and remanence and in some contexts the two terms may be used interchangeably remanent induction The remaining magnetic induction in a magnetic material after an applied field is reduced to Zero Also see remanence repeatability The closeness of agreement among repeated measurements of the same variable under the same conditions resolution The degree to which nearly equal values of a quantity can be discriminated display resolution The resolution the physical display of an instrument This is not always the same as the measurement resolu
65. circuits Installation personnel shall observe all safety regulations at all times Turn off system power before making or breaking electrical connections Regard any exposed connector terminal board or circuit board as a possible shock hazard Discharge charged components only when such grounding results in no equipment damage If a test connection to energized equipment is required make the test equipment ground connection before probing the voltage or signal to be tested Do not install or service equipment alone Do not reach into or adjust the equipment without having 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 refer to Paragraph 6 4 Use this procedure to periodically clean the instrument 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 nof use aromatic hydrocarbons or chlorinated solvents to clean the instrument They may react with the plastic materials used in the case or the silk screen printing on the back panel 2 Clean the surface of printed circuit boards PCBs with clean dry air at low pressure If the keyboard locks up hold the Escape key for about 20 seconds to reset the Model 450 to factory defaults The gaussmeter then requires the user to re enter setpoints and zer
66. de setting Use the alarm inside setup to look for good readings For example to check 1 kG magnets for a tolerance of 0 25 kG set the high alarm point 1 25 kG and the low alarm point to 0 75 kG The diagram below illustrates when the alarm is ON or OFF Alarm Se Geht Dead SE Off n 3 kG 2 kG 1 KG 0 kG 1 KG 2 KG 3 kG Example of operation with tb Low Alarm 1 alarm triggered by Point readings INSIDE user defined setpoints High Alarm Point 3 8 Operation Lake Shore Model 450 Gaussmeter User s Manual To enter this alarm setup push Alarm Set The unit prompts for the High Alarm Point The initial range displayed is the same as the latest probe range To set an alarm in a different Se vu range push Select Range until the proper range displays Then use the numeric keypad to enter the high alarm point After entering the desired high alarm point press Enter to accept the new value or Escape to retain the old value The display proceeds to the Low Alarm Point The initial range displayed is the same as the latest probe range To set an alarm in a different range push Select Range until the proper range displays Then use the numeric keypad to enter the low alarm point After entering the desired alarm point press Enter to accept the new value or Escape to retain the old value The alarm setpoints are absolute unsigned i e only the magnitude of the field reading is used After entering proper high and low alarm p
67. e probe will exhibit its full accuracy if used without the extension cable Part numbers and cables lengths are defined as follows MPEC 10 Probe Extension Cable 3 meters 10 feet MPEC 25 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 5 2 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual 5 3 LAKE SHORE STANDARD PROBES There are several types of Lake Shore Model 450 probes available Transverse Axial Flexible Transverse and Gamma each named by its Hall sensor orientation Because the Model 450 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 Please consult the factory for availability of probe types not detailed in this section Information on Hall generators is presented in Appendix C of this manual 5 3 1 Probe Selection Criteria Some guidelines are provided below to aid in the selection of a probe for you application 1 2 Choose a probe to match the application Do not buy more accuracy field range or fragility than is actually necessary The thinner a probe the more fragile it is Try to avoid the temptation to select an easily damaged probe based on a possible but not probable future application For instance avoid using an exposed device probe such a
68. ed represents the sum of the bit weighting of the event flag bits in the Standard Event Status Register Query Identification IDN lt manufacturer gt lt model number gt lt serial number gt lt firmware date gt Format LSCI MODEL450 a nnnnnn term Identifies the instrument model and software level Operation Complete Command OPC Nothing Generates an Operation Complete event in the Event Status Register upon completion of all pending selected device operations Send it as the last command in a command string Query Operation Complete OPC 1 Format n term Places a 1 in the controller output queue upon completion of all pending selected device operations Send as the last command in a command string Not the same as OPC 4 11 Lake Shore Model 450 Gaussmeter User s Manual RST Reset Instrument Input RST Returned Nothing Remarks Sets controller parameters to power up settings SRE Configure Status Reports in the Service Request Enable Register Input SRE lt bit weighting gt Returned Nothing Remarks Each bit has a bit weighting and represents the enable disable status of the corresponding status flag bit in the Status Byte Register To enable a status flag bit send the command SRE with the sum of the bit weighting for each desired bit See the STB command for a list of status flags Example To enable status flags 0 3 4 and 6 send the command SRE 89 term 89 is the sum of the bit weight
69. efer to Paragraph 3 6 1 Set Display Filter Points FNUM XX Nothing Sets filter points XX 2 thru 64 Numbers 2 thru 8 produce a linear filter response Numbers 9 thru 64 produce an exponential filter response In general the higher the number the longer the display settle time Refer to Paragraph 3 6 1 Remote Operation FNUM Input Returned Remarks FWIN Input Returned Remarks FWIN Input Returned Remarks LOCK Input Returned Remarks LOCK Input Returned Remarks MAX Input Returned Remarks MAX Input Returned Remarks MAXC Input Returned Remarks MAXR Input Returned Remarks Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Display Filter Points Query FNUM XX Queries filter points setting XX 2 thru 64 Numbers 2 thru 8 produce a linear filter response Numbers 9 thru 64 produce an exponential filter response In general the higher the number the longer the display settle time Refer to Paragraph 3 6 1 Set Display Filter Points FWIN XX Nothing Sets the filter window XX 1 thru 10 The smaller the percentage the smaller the change in magnetic field that causes the filter to restart Refer to Paragraph 3 6 1 Display Filter Points Query FWIN XX Queries filter window setting XX 1 thru 10 The smaller the percentage the smaller the change in magnetic field that causes the filter to restart Refer t
70. enerator meeting the sensitivity ranges given below Calibration or sensitivity constant and serial number of the Hall generator 1 Setthe Lake Shore Model 450 Gaussmeter to 300 Baud Refer Paragraph 3 11 of this User s Manual on how to set the Gaussmeter to communicate at 300 Baud 2 Insert the 3 5 inch disk and type in the default drive A or B Type in HALLCAL This will execute the HALLCAL EXE program 4 The program will prompt for the Probe serial number Any combination of 6 letters or number can be entered Press Enter when this is accomplished 5 The program will prompt for the probe type 0 or 1 Enter 0 for Hall generators with sensitivities between 5 5 and 10 5 mV kG 100 mA current Enter 1 for Hall generators with sensitivities between 0 55 and 1 05 mV KG 100 mA current 6 The program will prompt for the Calibration Constant Enter the magnetic sensitivity in mV kG at a control current of 100 mA Remember to account for the 420 Q input impedance of the Gaussmeter when calculating the proper load resistor to install 7 The program will display all the values entered along with designated F keys F1 Probe Serial Number ABC123 F2 Probe Type 0 F3 Calibration Constant X XXX F10 Program Probe Esc Exit Program 8 Atthis 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
71. ep 8 54 x 3 5 x 12 5 inches half rack package Weight 3 kilograms 6 6 pounds Introduction 1 2 1 3 Lake Shore Model 450 Gaussmeter User s Manual SAFETY SUMMARY Observe the following general safety precautions during all phases 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 use of the instrument Lake Shore Cryotronics Inc assumes no liability for customer failure to comply with these requirements The Model 450 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 temperatures up to 31 C decreasing linearly to 50 at 40 C e Power supply voltage fluctuations not to exceed 10 of the nominal voltage Ground The Instrument To minimize shock hazard connect instrument chassis and cabinet to electrical ground The instrument is equipped with a 3 conductor AC power cable either plug it into an approved 3 contact outlet or use a 3 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
72. er string from the Model 450 e 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 Table 4 3 Sample BASIC Serial Interface Program SEREXAM BAS EXAMPLE PROGRAM FOR SERIAL INTERFACE This program works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible with a serial interface It uses the COM1 communication port at 9600 BAUD Enter an instrument command or query at the prompt The command transmits to the instrument which displays any query response Type EXIT to exit the program NOTE The INPUT instruction in this example accepts no commas as part of an input string If a comma appears in an instrument command replace it with a space CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may need more BAUDS 9600 TERMS CHR 13 CHR 10 Terminators are lt CR gt lt LF gt OPEN COM1 BAUDS 0 7 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 CMD CMDS TERMS PRINT 1 CMDS Send command to instrument IF INSTR CMD lt gt 0 THEN Test for query RS If query read response N 0 Clr return string and count WHILE N lt
73. er to accept the new setting or Escape to retain the old setting and return to the normal display Do not use Auto Ranging with Peak and 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 4 Operation Lake Shore Model 450 Gaussmeter User s Manual 3 5 AC DC AND PEAK RMS The AC DC key toggles between AC and DC measurements The annunciator immediately changes from DC to PK or RMS as applicable One update cycle is required for a new display value The Model 450 updates the field reading 5 times per second For faster updates refer to Fast Data Mode in Paragraph 3 16 In DC operation the display shows the DC field at the probe with sign orientation followed by the appropriate field units the letters DC displaying 4 digits with filter OFF or 5 digits with Filter ON The DC value is available over the IEEE 488 and Serial Interfaces and both Analog Outputs In AC operation select either RMS or Peak Both meet specified accuracy from 10 to 400 Hz The lowest range for the type probe installed is not available in the AC Peak mode The AC RMS reading is a measurement of true RMS defined as the square root of the average of the square of the field function taken through one period The RMS reading works on complex waveforms to a crest factor of 7 and rejects the DC component if it is not large enough to overload t
74. er with a discrete number of voltage levels anode The terminal that is positive with respect to the other terminal when the diode is biased in the forward direction Anode Cathode area A measure of the size of a two dimensional surface or of a region on such a surface area turns A coil parameter produced by the multiplication of a magnet s area and number of turns Gives an indication of the sensitivity of a coil In the Model 480 the area turns of a coil must be entered to perform flux density measurements in units of gauss G or tesla T B Symbol for magnetic flux density See Magnetic Flux Density baud A unit of signaling speed equal to the number of discrete conditions or signal events per second or the reciprocal of the time of the shortest signal element in a character bit A contraction of the term binary digit a unit of information represented by either a zero ora one Glossary of Terminology A 1 Lake Shore Model 450 Gaussmeter User s Manual calibration To determine by measurement or comparison with a standard the correct accurate value of each scale reading on a meter or other device or the correct value for each setting of a Jen knob cathode The terminal from which forward current flows to the external circuit Anode gt Cathode Celsius C Scale A temperature scale that registers the freezing point of water as 0 C and the boiling point as 100 C under norma
75. erything that contacts it to ground potential by providing a conductive surface and discharge paths As a minimum observe these precautions 1 De energize or disconnect all power and signal sources and loads used with unit 2 Place unit on a grounded conductive work surface 3 Ground technician through a conductive wrist strap or other device using 1 MQ series resistor to protect operator 4 Ground any tools such as soldering equipment that will contact unit Contact with operator s hands provides a sufficient ground for tools that are otherwise electrically isolated 5 Place ESDS devices and assemblies removed from a unit on a conductive work surface or in a conductive container An operator inserting or removing a device or assembly from a container must maintain contact with a conductive portion of the container Use only plastic bags approved for storage of ESD material 6 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 instrument line voltage selector Verify the fuse value whenever line voltage is changed WARNING To avoid potentially lethal shocks turn off gaussmeter and disconnect it from AC power before performing these procedures Identify the line input assembly on the instrument rear panel See Figure 6 1 Turn the line power switch OFF 0 Remove the instrument power cord With a small screwd
76. es for each probe sensitivity along with fixed display resolution High Stability Probe HST Gauss Tesla Resolution Resolution Range AC or DC i Range AC or DC e w Filter Off DC Filter On er wl Filter Off PC Filter On High Sensitivity Probe HSE ass 1 gt Tela Range AC or DC Range AC or DC e wi Filter Off PC Filter On wi Filter Off PC Filter On 0 001G 3mT 0 0001mT 0 00001 mT Ultra High Sensitivity Probe UHS Gaus 1 Testa Resolution Resolution Range AG or DC z Range AC or DC i 0 01mG 0 001 mG 30 uT 0 001 uf For manual ranging press Select Range to view the full scale value for the present range The display to the right appears Press Select Range or the A or V keys to cycle through allowable full scale ranges for the installed probe Press Enter to accept the new range or Escape to retain the old range Changing ranges in this way disables the Auto Range function until Auto Range is pressed NOTE In AC Peak Mode only you cannot select the lowest range for the installed probe This is true for both Manual and Auto Range In Auto Range mode the Model 450 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 in some conditions Press Auto Range to display the screen to the right Press Auto Range or the A or V keys to cycle between On and Off Push Ent
77. es unit for RMS or Peak measurements 0 RMS 1 Peak RMS or Peak is selected after ACDC is set to AC Peak or RMS Magnetic Field Reading Query PRMS Oorl Queries Peak or RMS measurement status 0 RMS or 1 Peak RMS or Peak is selected after ACDC is set to AC 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 Refer to Paragraph 3 4 Manual Range Query RANGE 0 1 2 o0r3 Queries manual range Range depends on type of probe installed There are four ranges possible for each probe 0 highest through 3 lowest Refer to Paragraph 3 4 Set Relative Mode Status REL O 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 Remote Operation RELRM Input Returned Remarks RELS Input Returned Remarks RELS Input Returned Remarks RELSM Input Returned Remarks UNIT Input Returned Remarks UNIT Input Returned Remarks Lake Shore Model 450 Gaussmeter User s Manual Relative Mode Reading Multiplier Query RELRM u m k or Queries relative reading multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000
78. et Fast Data Mode SRE Query Service Request Enable FAST Fast Data Model Status Query STB Query Status Byte FIELD Present Field Reading Query TST Query Self Test FIELDM Present Field Multiplier Query WAI Wait To Continue FILT Set Display Filter Status Interface Commands FILT e Filter Query ADDR Set Address FNUM et Filter Points ADDR Address Query FNUM Filter Points Query BAUD Set Serial Interface Baud Rate FWIN Set Filter Window FWIN Filter Window Query 2 Ee Serial Interface Baud Rate Query LOCK Set Keyboard Lock Statue LOCK Keyboard Lock Query END EOI Query MODE Remote Mode MAX Set Max Hold Status MODE Remote Mode Query MAX Max Hold Query TERM Terminator MAXC Initiate Max Clear Reset MAXR Max Reading Query TERM oe Jester Query MAXRM Max Reading Multiplier Query Device Specific Commands PRMS Set Peak RMS AC Field Status ACDC Set AC DC Field Reading Status PRMS Peak RMS AC Field Reading Query ACDC AC DC Field Reading Query RANGE Set Manual Range Status ALARM Set Alarm Function On Off RANGE Manual Range Query ALARM Alarm Query REL Set Relative Mode Status ALMB Set Audible Alarm Status REL Relative Mode Query ALMB Audible Alarm Query RELR Relative Mode Reading Query ALMH Set Alarm High Point RELRM Relative Mode Reading Multiplier ALMH Alarm High Point Query RELS Set Relative Mode Setpoint ALMHM Alarm High Point Multiplier Query RELS Relative Mode Setpoint Query ALMIO Set Alarm Trigger I
79. ff 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 3 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 DB 25 Adapters that permit connection to a computer Refer to Paragraph 4 2 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 However the scaling of the corrected output may be reconfigured The monitor output is a live analog signal proportional to the magnetic flux density waveform Refer to Paragraph 3 12 for further operational information 5 Probe Input Connector The probe plugs into the DA 15 connector Always turn off the instrument before connecting the probe Align the 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
80. g 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 gt E p Protective conductor terminal Frame or chassis terminal On supply Off supply f Fuse O Ot ede Introduction 1 5 Lake Shore Model 450 Gaussmeter User s Manual This Page Intentionally Left Blank Introduction Lake Shore Model 450 Gaussmeter User s Manual 2 0 2 1 2 2 CHAPTER 2 INSTALLATION GENERAL This chapter covers general Model 450 installation instructions Inspection and unpacking in Paragraph 2 1 repackaging for shipment in Paragraph 2 2 definition of rear panel connections in Paragraph 2 3 and initial setup and system checkout procedure in Paragraph 2 4 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 c
81. gn or transfer this license or this software is void To maintain software warranty the source code must not be modified Any changes made to the HALLCAL EXE source code is at the user s risk Lake Shore assumes no responsibility for damage or errors incurred as result of any changes made to the source code This agreement allows you to use the HALLCAL EXE Software on any one computer system One archival floppy disk is permitted Any unauthorized duplication or use of the software in whole or in part in print or in any other storage and retrieval system is forbidden Lake Shore works to ensure the HALLCAL EXE Software is as free of errors as possible and that the results you obtain from the system are accurate and reliable However understand that with any computer software the possibility of software errors exist In any important research as when using any laboratory equipment results should be carefully examined and rechecked before final conclusions are drawn Neither Lake Shore nor anyone else involved in the creation or production of this software can pay for loss of time inconvenience lost of use of the product or property damage caused by this product or its failure to work or any other incidental or consequential damages Use of our product implies that you understand the Lake Shore license agreement and statement of limited warranty TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distinguish their pr
82. h 4 3 However without the advantage of the IEEE 488 Architecture there are several limitations e No Bus Control Commands apply e Only IDN and RST Common Commands are usable e Terminators are fixed to CRLF A query must be added to the end of a command string if the Model 450 must return information Over IEEE 488 the last query response is sent when addressed to talk For example UNIT G UNIT sets the units to gauss and immediately queries unit status LSCI Model 4002 RJ 11 to DB 25 Adapter SERIAL I O RS 232C Interface Output on rear of Model 450 To Customer Supplied Computer DB 25 Serial Interface Connector Use whichever adapter that matches your computer serial interface connector LSCI Model 4003 RJ 11 to DE 9 Adapter LSCI Model 4001 RJ 11 Cable Assembly To Customer Supplied Computer DE 9 Serial Interface Connector C 450 U 4 2 Figure 4 2 Serial Interface Adapters Remote Operation 4 7 Lake Shore Model 450 Gaussmeter User s Manual 4 2 1 Serial Interface Hardware Configuration Below is a technical description of the Serial Interface Table 4 2 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
83. he contribution of the magnetic material B to the total magnetic induction B B B HoH SI Bj B H cgs isolated neutral system A system that has no intentional connection to ground except through indicating measuring or protective devices of very high impedance Kelvin K The unit of temperature on the Kelvin Scale It is one of the base units of SI The word degree and its symbol are omitted from this unit See Temperature Scale for conversions Kelvin Scale The Kelvin Thermodynamic Temperature Scale is the basis for all international scales including ITS 90 It is fixed at two points the absolute zero of temperature 0 K and the triple point of water 273 16 K the equilibrium temperature that pure water reaches in the presence of ice and its own vapor Glossary of Terminology A 3 Lake Shore Model 450 Gaussmeter User s Manual line regulation The maximum steady state amount that the output voltage or current will change as the result of a specified change in input line voltage usually for a step change between 105 125 or 210 250 volts unless otherwise specified line of flux An imaginary line in a magnetic field of force whose tangent at any point gives the direction of the field at that point the lines are spaced so that the number through a unit area perpendicular to the field represents the intensity of the field Also know as a Maxwell in the cgs system of units line voltage The RMS voltage of the pr
84. he relative setpoint The first method captures the field reading nulling the present field The field reading displays as the setpoint upon pressing Relative Set Press Enter to accept the setpoint or Escape to retain the old value and quit the Relative Set function The second method is by keypad entry Press Relative Set and change the setpoint by pressing number keys or using the A or W keys Press Select Range to enter a setpoint different from the current range Press Enter to accept the new setpoint or Escape to return to the old value Once the relative setpoint is established push Relative On Off to initiate the relative function 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 ANE aam is active the alain poins follow the relative reading When Relative and Max Hold bom O pom functions are used at the same time the relative reading is 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 displays 3
85. he selected range The AC Peak readings can be used in two different ways With Max Hold OFF it measures the Peak Crest of a periodic symmetrical waveform If field change at the probe is unpredictable the peak reading will not always show the largest field value In this case check monitor output with an oscilloscope to see how the reading relates to the field With Max Hold ON the Peak reading measures the amplitude of a single peak like a magnetizing pulse lt captures the reading until reset with Max Reset The AC value is available over the IEEE 488 and Serial Interfaces 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 Paragraph 3 3 Ap FILTER The Filter key initiates the display filter function Paragraph 3 6 1 Press and hold Filter for about 5 seconds to display field and temperature compensation Paragraph 3 6 2 3 6 1 Display Filter The display filter function quiets the display making it more readable when the probe is exposed to a noisy field Take care when using the filter on changing fields it may level off peaks and slow instrument response Users may configure the filter function to view desired field ch
86. hese commands transmit with the Attention ATN line asserted low The Model 450 recognizes two Multiline commands LLO Local Lockout Prevents the use of instrument front panel controls DCL Device Clear Clears Model 450 interface activity and puts it into a bus idle state Finally Addressed Bus Control Commands are Multiline commands that must include the Model 450 listen address before the instrument responds Only the addressed device responds to these commands The Model 450 recognizes three of the Addressed Bus Control Commands SDC Selective Device Clear The SDC command performs essentially the same function as the DCL command except that only the addressed device responds GTL Go To Local The GTL command is used to remove instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously locked out with the LLO command SPE Serial Poll Enable and SPD Serial Poll Disable Serial polling accesses the Service Request SRQ Status Register This status register contains important operational information from the unit requesting service The SPD command ends the polling sequence 4 1 22 Common Commands Common Commands are addressed commands which create commonalty between instruments on the bus All instruments that comply with the IEEE 488 1987 standard share these commands and their format Common commands all begin with an asterisk They generally relate to
87. his Page Intentionally Left Blank Service Lake Shore Model 450 Gaussmeter User s Manual APPENDIX A GLOSSARY OF TERMINOLOGY accuracy The degree of correctness with which a measured value agrees with the true value electronic accuracy The accuracy of an instrument independent of the sensor sensor accuracy The accuracy of a Hall generator and its associated calibration algorithm A set of well defined rules for the solution of a problem in a finite number of steps American Standard Code for Information Exchange ASCII A standard code used in data transmission in which 128 numerals letters symbols and special control codes are represented by a 7 bit binary number as follows WD OCOIN MD U1 Al Ww mi O D Yo IN lt Ix lt c H u ajo o u Tia a ls x z lt Je je jojo N lolololololololo 4 lo ololol Jojojolo a gr lojo 0ojola olo lolo 7 lo fo o oj of ol ol fo o 3 3 x to alo ajo joja j o olz la Irizle H I mImlo 0l ml mal yu lAl American Wire Gage AWG Wiring sizes are defined as diameters in inches and millimeters as follows AWG _ Dia In Dia mm AWG Dia In Dia mm AWG Dia In Dia mm AWG _ Dia In Dia mm 1 0 2893 7 348 11 0 0907 2 304 21 0 0285 0 7230 31 0 0089 0 2268 2 0 2576 6 544 12 0 0808 2 053 22 0 0253 0 643
88. imary power source to an instrument load regulation A steady state decrease of the value of the specified variable resulting from a specified increase in load generally from no load to full load unless otherwise specified M Symbol for magnetization See magnetization magnetic air gap The air space or non magnetic portion of a magnetic circuit magnetic field strength H The magnetizing force generated by currents and magnetic poles For most applications the magnetic field strength can be thought of as the applied field generated for example by a superconducting magnet The magnetic field strength is not a property of materials Measure in SI units of A m or cgs units of oersted magnetic flux density B Also referred to as magnetic induction This is the net magnetic response of a medium to an applied field H The relationship is given by the following equation B uo H M for SI and B H 47M for cgs where H magnetic field strength M magnetization and Ho permeability of free space 47 x 10 H m magnetic hysteresis The property of a magnetic material where the magnetic induction B for a given magnetic field strength H depends upon the past history of the samples magnetization magnetic induction B See magnetic flux density magnetic moment m This is the fundamental magnetic property measured with dc magnetic measurements systems such as a vibrating sample magnetometer extraction magnetometer SQUID magnet
89. ing for each bit Bit Bit Weighting Event Name 0 1 New A amp B 3 8 Alarm 4 16 Error 6 64 SRQ 89 SRE Query the Configuration of Status Reports in the Service Request Enable Register Input SRE Returned lt SRE bit weighting gt Format nnn term Remarks The integer returned represents the sum of the bit weighting of the enabled bits in the Service Request Enable Register See the STB command for a list of status flags STB Query Status Byte Input STB Returned lt STB bit weighting gt Format nnn term Remarks Acts like a serial poll but does not reset the register to all zeros The integer returned represents the sum of the bit weighting of the status flag bits that are set in the Status Byte Register TST Query Self Test Input TST Returned 0 or 1 Format n term Remarks The Model 330 performs a self test at power up 0 no errors found 1 errors found WAI Wait to Continue Input WAI Returned Nothing Remarks Prevents execution of any further commands or queries until completion of all previous ones Changing the sample sensor and reading it immediately with a device dependent query may result in a reading error because the sensor needs time to stabilize Place a WAI between the sensor change and query for a correct reading Achieve the same results with repeated queries or using a Service Request but WAI is easier Send WAI as the last command in a command string followed by appropriate termination It cann
90. installed on the gaussmeter but not in use the protective tubes provided with many probes should be placed over the probe handle and stem in order to protect the tip When the gaussmeter is not in use the probes should be stored separately in some type of rigid container The cardboard and foam container that Lake Shore probes are shipped in may be retained for probe storage For further details on available accessories and probes refer to Chapter 5 Operation 3 13 Lake Shore Model 450 Gaussmeter User s Manual Do not bend from tip of probe A ie El LakeShore The tip is Flexible Transverse Probe VERY FRAGILE Maximum Bend Angle C 421 3 4 eps Figure 3 4 Maximum Flexible Probe Bend Radius 3 15 3 Probe Operation In the DC mode of operation the orientation of the probe affects the polarity reading of the gaussmeter On a transverse probe the Lake Shore name printed on the handle indicates the side for positive flux entry On an axial probe positive flux entry is always from the front of the probe See Figure 3 5 NOTE For best 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 meas
91. l atmospheric pressure Celsius degrees are purely derived units calculated from the Kelvin Thermodynamic Scale Formerly known as centigrade See Temperature for conversions cgs system of units A system in which the basic units are the centimeter gram and second coercive force coercive field The magnetic field strength H required to reduce the magnetic induction B in a magnetic material to zero coercivity generally used to designate the magnetic field strength H required to reduce the magnetic induction B in a magnetic material to zero from saturation The coercivity would be the upper limit to the coercive force compliance voltage See current source Curie temperature Tc Temperature at which a magnetized sample is completely demagnetized due to thermal agitation Named for Pierre Curie 1859 1906 a French chemist current source A type of power supply that supplies a constant current through a variable load resistance by automatically varying its compliance voltage A single specification given as compliance voltage means the output current is within specification when the compliance voltage is between zero and the specified voltage demagnetization when a sample is exposed to an applied field Ha poles are induced on the surface of the sample Some of the returned flux from these poles is inside of the sample This returned flux tends to decrease the net magnetic field strength internal to the sample yieldi
92. l numbers end in VG are usable on full scale ranges of 300 gauss 30 millitesla to 30 kilogauss 3 tesla The High Sensitivity family of probes i e VH models can be used on 30 G 3 mT to 30 KG 3 T full scale ranges High field probes are specially calibrated to provide use above 30 kG 3 T and the Gamma Probe operates on the 300 mG 30 uT and 3 G 300 uT ranges If none of the standard probe configurations seem to fit your needs always remember that Lake Shore can provide custom probes to meet your physical temperature and accuracy requirements Contact Lake Shore with details of your special requirements 5 3 2 Radiation Effects on Gaussmeter Probes The HST and HSE probes use a highly doped indium arsenide active material The HST material is the more highly doped of the two and therefore will be less affected by radiation Some general information relating to highly doped indium arsenide Hall generators is as follows Gamma radiation seems to have little effect on the Hall generators Proton radiation up to 10 Mrad causes sensitivity changes lt 0 5 e Neutron cumulative radiation gt 0 1 MeV 10 sq cm can cause a 3 to 5 decrease in sensitivity In all cases the radiation effects seem to saturate and diminish with length of time exposed Accessories and Probes 5 3 Lake Shore Model 450 Gaussmeter User s Manual 5 3 3 Probe Specifications Terminology used in Figures 5 1 thru 5 4 are defined as follows Defini
93. l on top identifying the software version and date see Figure 6 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 Set power switch to Off O and disconnect power cord from rear of unit Use 5 64 hex key to remove four screws attaching top panel to unit Use 5 64 hex key to loosen two screws attaching bottom panel to unit Carefully remove back bezel Slide top panel back and remove from unit Locate software EPROM U36 on main circuit board Note its orientation circular notch on front of IC See Figure 6 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 tighten two screws attaching bottom panel to unit 11 Reconnect power cord to rear of unit and set power switch to On I 12 Perform the initial setup and system checkout Paragraph 2 4 When replacing the operating software EPROM all operating parameters reset to factory defaults specified in Paragraph 3 14 Wee DEER la Operating Software Transformer Power Inlet oak wn gt Front Rear C 450 U 6 9 Figure 6 9 Location Of Operating Software EPROM Service 6 7 Lake Shore Model 450 Gaussmeter User s Manual T
94. last temperature reading prior to FAST DATA MODE activation The temperature is not updated during FAST DATA MODE Use the normal interface command to query field measurement data Without display overhead the instrument can take 18 new readings each second An efficiently written IEEE 488 program can return all 18 readings without slowing the instrument down When using the IEEE 488 Interface never try to read faster than 18 readings a second The additional overhead associated with Serial Communication slows instrument Serial Interface communications to a maximum of 15 readings per second at 9600 Baud When using the Serial Interface never try to read faster than 15 readings a second Operation Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 4 REMOTE OPERATION 4 0 GENERAL Either of the two computer interfaces provided with the Model 450 permit remote operation First is the IEEE 488 Interface in Paragraph 4 1 and second is the Serial Interface in Paragraph 4 2 The two interfaces share a common set of commands provided in Paragraph 4 3 Use only one of the interfaces at a time 4 1 IEEE 488 INTERFACE The IEEE 488 Interface is an instrumentation bus with hardware and programming standards that simplify instrument interfacing The Model 450 IEEE 488 Interface complies with the IEEE 488 2 1987 standard and incorporates its functional electrical and mechanical specifications unless otherwise specified in this manual All in
95. ly in the form of a lagging of a physical effect behind its cause Also see magnetic hysteresis IEEE Institute of Electrical and Electronics Engineers IEEE 488 An instrumentation bus with hardware and programming standards designed to simplify instrument interfacing The addressable parallel bus specification is defined by the IEEE initial permeability The permeability determined at H 0 and B 0 initial susceptibility The susceptibility determined at H 0 and M 0 integrator A circuit or network whose output waveform is the time integral of its input waveform In the Model 480 the input is a voltage with the integral output being in volt seconds V s 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 Syst me International d Unit s SI was promulgated in 1960 by the Eleventh General Conference on Weights and Measures For definition spelling and protocols see Reference 3 for a short convenient guide interpolation table A table listing the output and sensitivity of a sensor at regular or defined points which may be different from the points at which calibration data was taken intrinsic coercivity The magnetic field strength H required to reduce the magnetization M or intrinsic induction in a magnetic material to zero intrinsic induction T
96. meter User s Manual APPENDIX C HALL GENERATORS GENERAL This chapter provides theory of operation specifications mechanical drawings and definition of terminology Hall Generator theory of operation is detailed in Paragraph C2 0 Generic Hall generator hookup is detailed in Paragraph C3 0 Hookup to a Model 450 Gaussmeter is discussed in Paragraph C4 0 Specifications of the various available Hall generators are detailed in Paragraph C5 0 Finally the HALLCAL EXE program is detailed in Paragraph C6 0 Additional installation and calibration information is available in Lake Shore Document Number C25001 Hall Generator Installation Instructions THEORY OF OPERATION The Hall effect was discovered by E H Hall in 1879 For nearly 70 years it remained a laboratory curiosity Finally development of semiconductors 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 As implied by its name this device relies on the Hall effect The Hall effect is the development of a voltage across a sheet of conductor when current is flowing and the conductor is placed in a magnetic field See Figure C 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
97. mum linearity error 1 0 RDG 1 RDG 0 30 RDG sensitivity versus field 10 to 10 kG 30 to 30 KG 10 to 10 KG 1 5 RDG 1 25 RDG 100 to 100 KG 30 to 30 KG Zero field offset voltage Ic 100 uV max 50 uV max 75 uV max nominal control current Operating temperature 40 to 100 C 40 to 100 C 40 to 100 range Mean temperature 0 08 C max 0 005 C max 0 04 C max coefficient of magnetic sensitivity Mean temperature 1 yV C max 10 4 uV C max 0 3 V C coefficient of offset Io nominal control current Mean temperature 0 18 C approx 0 15 C approx 0 18 C approx coefficient of resistance Leads 34 AWG copper with poly 34 AWG copper with poly 34 AWG copper with poly nylon insulation nylon insulation nylon insulation Hall Generator C 7 Lake Shore Model 450 Gaussmeter User s Manual C6 0 HALLCAL EXE PROGRAM The HALLCAL EXE program was developed by Lake Shore Cryotronics Inc to allow the interfacing of customer attached Hall generators to the Model 450 Gaussmeter Please refer to the Software License Agreement behind the title page of this manual Because of the many intricacies involved with proper calibration the Customer must accept responsibility for the measurement accuracy Requirements Lake Shore Model 450 Gaussmeter connected via RS 232 to the computer in the COM1 port Lake Shore Model MCBL 6 Cable Assembly IBM or compatible CPU Hall g
98. ng a true internal field Hint given by Hint Ha DM where M is the volume magnetization and D is the demagnetization factor D is dependent on the sample geometry and orientation with respect to the field deviation The difference between the actual value of a controlled variable and the desired value corresponding to the setpoint differential permeability The slope of a B versus H curve ua dB dH differential susceptibility The slope of a M versus H curve xa dM dH digital controller A feedback control system where the feedback device sensor and control actuator heater are joined by a digital processor In Lake Shore controllers the heater output is maintained as a variable DC current source digital data Pertaining to data in the form of digits or interval quantities Contrast with analog data dimensionless sensitivity Sensitivity of a physical quantity to a stimulus expressed in dimensionless terms The dimensionless temperature sensitivity of a resistance temperature sensor is expressed as Sg T R dR dT which is also equal to the slope of R versus T on a log log plot that is Sy d INR d InT Note that the absolute temperature in kelvin must be used in these expressions drift instrument An undesired but relatively slow change in output over a period of time with a fixed reference input Note Drift is usually expressed in percent of the maximum rated value of the variable being measured dynamic data
99. ng with a DA 15 connector on one end and four leads on the other The Hall generator is a 4 lead device The 4 leads are labeled lc Red Ic Black or Green VH Blue and VH Yellow corresponding to the 4 leads on all the Hall generators The Model 450 has an input impedance of 420 Q Therefore the actual sensitivity at the gaussmeter input will be less than the value given with the Hall generator due to drop in the leads and cable This fact is important because a sensitivity value is supposed to be loaded into the cable PROM to set calibration We recommend that 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 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 are two reasons for this 1 The gaussmeter current source is normally limited in compliance voltage The Model 450 should not drive a load Hall generator Wires in cryostat and probe cable greater than 50 Q In fact for best performance the load should be less than 30 Q 2 Because the Model 450 input impedance is 420 Q there is a volt
100. nnnnonnrnnnn nar nnnenntrnnnn nn nnnnneennnrnnnnnnnnen 4 2 4 1 2 2 COMMON COMME e e a 4 2 4 1 2 3 Interface and Device Specific Commandes ooococococococinonoconanononcnnnnnnnnnnnononnnnncnnnnnnnnnnnnn 4 2 4 1 3 Status Register S g asia eit Ladi ann dare near ete iit anden dead Edi 4 3 4 1 3 1 Status Byte Register and Service Request Enable Register arrrrnnnrnnrrnnvonnrrnnnnnnnnn 4 3 Lake Shore Model 450 Gaussmeter User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 4 1 3 2 Standard Event Status Register and Standard Event Status Enable Register 4 3 4 1 4 Example IEEE Setup and Program 4 4 4 1 4 1 GPIB Board Installation cnn anar nn nn cnn daiat 4 4 4 1 4 2 Running the Example QuickBasic Program 4 4 4 1 5 Notes on Using the IEEE Interface AA 4 5 4 2 Serial I O Interface iii ENNEN ENNEN dee 4 7 4 2 1 Serial Interface Confiouration nn cnn nn nn cnc nan nnc cnn non cnc nana nncnnnnnns 4 8 4 2 2 Serial Interface Settings oirean EA EREE A EE 4 8 4 2 3 Sample BASIC Serial Interface Program 4 8 4 2 4 Notes on Using the Serial Interface ooooonnnocinnninocicononocannnnonannno nono ncnn nono narran rca rra rca 4 9 4 3 IEEE 488 Serial Interface Command Summary 4 10 4 3 1 Command List ne ET 4 10 4 3 2 ei ue Ren EI 4 11 4 3 3 Interface Commande 4 13 4 3 4 Device ee ee eu EE 4 14 4 3 5 Probe Specific Commande nn nnnnneenernnnn nn nnnnneensrnnnnnnnnn 4 22 5 ACCESSORIES AND PROBES eege rada
101. nside Outside RELSM Relative Mode Setpoint Multiplier ALMIO Alarm Trigger Inside Outside Query UNIT Set gauss or tesla Units ALML Set Alarm Low Point UNIT Gauss or tesla Units Query ALML Alarm Low Point Query Probe Commands ALMLM Alarm Low Point Multiplier Query FCOMP Set Field Compensation Status ALMS Alarm Status Query E ANOD Define Analog Out Default FCOMP Field Compensation Status Query SNUM Probe Serial Number Quer ANOD Anaog Qut Default Quen TCOMP Set Temp Compensation Status ANOH Define Analog Out High Setpoint TCOMP Temp Compensation Status Quer ANOH Analog Out High Setpoint Query TYPE i Boke T GE E ANOHM Analog Out High Setpoint Multiplier Sen Gem ei E SS E ANOL Define Analog Out Low Setpoint A O ANOL Analog Out Low Setpoint Query 4 3 1 Command List Structure Command Name Brief Description of Function RANGE Manual Reading Query Input RANGE Syntax of what user must input Returned 0 1 2 or 3 Information returned in response Remarks f to the query Used to query the unit for manual range Range i ar is dependent on type of probe installed There Explanation and definition of are four ranges possible for each probe where 0 returned data is the highest and 3 is the lowest range 4 10 Remote Operation 4 3 2 CLS Input Returned Remarks ESE Input Returned Remarks Example ESE Input Returned Remarks ESR Input Returned Remarks IDN Input
102. ntrols Refer to Paragraph 3 10 Address If using the IEEE 488 Interface press this key to adjust the bus address of the Model 450 and terminators Refer to Paragraph 3 10 Baud If using the Serial Interface press this key to select the Model 450 Baud Rate from 300 1200 or 9600 Refer to Paragraph 3 11 Analog Out Adjusts the scaling of the Corrected Analog Output The default setting makes the currently selected range the maximum and minimum values corresponding to the 3 volt and 3 volt outputs The Monitor Analog Output scaling cannot be modified Refer to Paragraph 3 12 Escape Terminates a function without changing existing settings Press and hold Escape for about 20 seconds to reset the instrument returning many parameters to factory defaults Refer to Paragraph 3 14 A Toggles between various settings shown in the display and increments a numerical display V Toggles between various settings shown in the display and decrements a numerical display Enter Accepts changes in the field display Press and hold Enter to access the Keypad Lock display and enter a 3 digit code to lockout the keypad from accepting changes 3 2 Operation Lake Shore Model 450 Gaussmeter User s Manual 3 1 2 Front Panel Display In normal operation the two row by twenty character vacuum fluorescent display provides magnetic readings on the top row and special information or readings on the bottom row Other information displays when using the
103. o Paragraph 3 6 1 Set Front Panel Keyboard Lock Status LOCK 0 Or LOCK 1 Nothing Sets front panel keyboard lock status 0 Unlocked 1 Locked Front Panel Keyboard Lock Query LOCK oor1 Queries front panel keyboard lock status 0 Unlocked 1 Locked Set Max Hold Status MAX 0 Or MAX 1 Nothing Sets the Max Hold feature 0 Off 1 On Works with the MAXR and MAXC commands Max Hold Query MAX 0or1 Queries Max Hold status 0 Off 1 On Works with the MAXR and MAXC commands 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 the plus sign five digits and decimal point Places decimal appropriate to range 4 19 MAXRM Input Returned Remarks PRMS Input Returned Remarks PRMS Input Returned Remarks RANGE Input Returned Remarks RANGE Input Returned Remarks REL Input Returned Remarks REL Input Returned Remarks RELR Input Returned Remarks 4 20 Lake Shore Model 450 Gaussmeter User s Manual Max Reading Multiplier Query MAXRM u m k or Queries maximum reading multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Set Peak or RMS Magnetic Field Reading Status PRMS 0 Or PRMS 1 Nothing Configur
104. o the probe 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 Service 6 1 Lake Shore Model 450 Gaussmeter User s Manual 6 2 1 Identification of Electrostatic Discharge Sensitive Components Below are various industry symbols used to label components as ESDS so AEE 6 2 2 Handling Electrostatic Discharge Sensitive Components Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and ev
105. odel 4001 RJ 11 Cable Assembiv cnn c nano nc nc nano nn nr nano rn rra rra rnnn rra 5 12 5 12 Model 4002 RJ 11 to DB 25 Adanter 5 12 5 13 Model 4003 RJ 11 to DE 9 Adapter ne gt 5 12 5 14 Model 4022 Rack Mount Kn 5 13 5 15 Model 4026 Dual Rack Mount Shelf rrrurrrannnvnrrnnanvvnnnnnnrrannenvrnnenevnnnnenvrannnenvrnnenennnnneerrnnnnenvvnnnune 5 14 6 1 Power EE 6 3 6 2 DA 15 PROBE INPUT Connector Details 6 4 6 3 Corrected and Monitor ANALOG OUTPUTS Connector Details 6 4 6 4 SERIAL I O RJ 11 Connector Details 6 4 6 5 IEEE 488 Connector Details im ear r aa a Sean iar e a aA Aaaa eaa ikona aitada 6 5 6 6 Model 4001 RJ 11 Cable Assembly Wiring Details mornnrrnnnnnnrrnnnrnnrrnnnnnnrrnnnrnnrrnnsrnnrrnnrersrrensennnn 6 6 6 7 Model 4002 RJ 11 to DB 25 Adapter Wiring Details 6 6 6 8 Model 4003 RJ 11 to DE 9 Adapter Wiring Details ornnrrnnnonnrrnnnnnnrrnnnnnnrrnnnrnnrrnnnrnsrrnnsersrrnneennnn 6 6 6 9 Location Of Operating Software EPROM A 6 7 C 1 Hall Generator Theory viii A eee iris C 2 C 2 Axial and Transverse Configurations oooononcccnnnoccccnnnoncccnononcccnnnnnnncnnnoncnc naar n cnc nano nc cnn nn nn cc cnn nnccnnnns C 2 C 3 Typical Hall Generator Hookup nn nn nnnnnntnrn nn nn nn nn cnnnnnnnnnn nn nn nnnnnnnnnnnnnnnnnnnnnnnnnnes C 4 C 4 Hall Generator Input Impedance anononnnnnnnnnnnnrnnnvnnonnnnnnnnnnnnnnntontrnn nn nn nnnnntentrnnnnnnnnnnntennrnnnnnnnnnnn C 4 C 5 Axial Hall Generator HGA 3010 HGA 3030 amp H
106. oducts 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 CalCurve Carbon Glass Cernox Duo Twist Quad Lead Quad Twist and SoftCal are trademarks of Lake Shore Cryotronics Inc MS DOS and Windows 95 98 NT are trademarks of Microsoft Corporation NI 488 2 is a trademark of National Instruments PC XT AT and PS 2 are trademarks of IBM Copyright 1992 2000 and 2002 by Lake Shore Cryotronics Inc All rights reserved No portion of this manual may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the express written permission of Lake Shore Lake Shore Model 450 Gaussmeter User s Manual DECLARATION OF CONFORMITY CE We Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville OH 43082 8888 USA hereby declare that the equipment specified conforms to the following Directives and Standards Application of Council Directives Standard to which Conformity is declared Model Number fete Signature John M Swartz Printed Name President Position 73 23 EEC 89 336 EEC EN55022 EN50082 1 EN61010 1 450 Aag a 1997 Date Lake Shore Model 450 Gaussmeter User s Manual Electromagnetic Compatibility EMC for the Model 450 Gaus
107. oints press Alarm On Off to activate the alarm The message Alarm On appears on the lower line of the display the musical note appears in the upper right hand corner of the display signifying alarm on To turn the alarm off again press the Alarm On Off key The message Alarm Off appears When the field reading is inside the alarm setpoints the musical note flashes and if turned ON the alarm sounds 3 10 LOCAL AND ADDRESS Normal front panel operation is called Local operation However the IEEE 488 Interface provides remote operation A Model 450 connected to a suitably equipped computer may either permit or inhibit front panel operation The Local key toggles between local front panel functional or remote front panel disabled The letter R displays in the upper right side of the display to signify Remote mode activation Before using the IEEE 488 Interface set the IEEE E and E Ne Address to display the screen to the right Press the A or W keys to a EN increment or decrement the IEEE Address to the required number Press Enter to accept the new number or Escape to retain the existing number The Model 450 automatically proceeds to the IEEE 488 Terminator display Press the A or Y keys to cycle through the following IEEE 488 Terminator choices Cr Lf Carriage Return and Line Feed LfCr Line Feed and Carriage Return LF Line Feed EOI End Or Identify Terminators are fixed to Cr Lf for the Serial Interface
108. ometer etc The exact technical definition relates to the torque exerted on a magnetized sample when placed in a magnetic field Note that the moment is a total attribute of a sample and alone does not necessarily supply sufficient information in understanding material properties A small highly magnetic sample can have exactly the same moment as a larger weakly magnetic sample see Magnetization Measured in SI units as A m and in cgs units as emu 1 emu 10 A m magnetic scalar potential The work which must be done against a magnetic field to bring a magnetic pole of unit strength from a reference point usually at infinity to the point in question Also know as magnetic potential magnetic units Units used in measuring magnetic quantities Includes ampere turn gauss gilbert line of force maxwell oersted and unit magnetic pole magnetization M This is a material specific property defined as the magnetic moment m per unit volume V M m V Measured in SI units as A m and in cgs units as emu cm 1 emu cm 10 A m Since the mass of a Get is generally much easier to determine than the volume magnetization is often alternately expressed as a mass magnetization defined as the moment per unit mass magnetostatic Pertaining to magnetic properties that do not depend upon the motion of magnetic fields 1 Maxwell Mx A cgs electromagnetic unit of magnetic flux equal to the magnetic flux which produces an electromotive force of 1
109. ormat of xxx xx allows a sign and resolution of 0 01 As a safety precaution this setting always equals zero if the instrument loses power or is turned off The setting cannot be changed from the front panel Refer to Paragraph 4 5 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 0 or 1 Queries Auto Range status 0 Off 1 On Set Front Panel Display Brightness BRIGT 0 thru 7 Nothing Sets front panel display brightness 0 lowest through 7 highest Default 4 Front Panel Display Brightness Query BRIGT O thru 7 Returns a single digit corresponding to the current display brightness setting 0 lowest through 7 highest Default 4 Set Front Panel Keyboard Lock Code CODE XXX Nothing Sets front panel keyboard lock code Default 123 Enter any three numbers 4 17 CODE Input Returned Remarks FAST Input Returned Remarks FAST Input Returned Remarks FIELD Input Returned Remarks FIELDM Input Returned Remarks FILT Input Returned Remarks FILT Input Returned Remarks FNUM Input Returned Remarks 4 18 Lake Shore Model 450 Gaussmeter User s Manual Front Panel Keyboard Lock Code Query CODE XXX Returns the 3 numbers that comprise the front panel keyboard lock code Set Fast Data Mode FAST 0 Or FAST 1 Nothing Sets Fast D
110. ot be embedded between other commands 4 12 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 3 3 INTERFACE COMMANDS ADDR Input address Returned Remarks ADDR Input Returned Remarks BAUD Input type Returned Remarks BAUD Input Returned END Input Returned Remarks END MODE Input Returned Remarks Example MODE Input Returned Remote Operation Input Returned Set IEEE Address ADDR address An integer from 1 to 30 Address 0 and 31 are reserved Nothing Sets the IEEE address The Model 450 is factory preset to 12 IEEE Address Query ADDR 1 to 30 Returns the current IEEE address setting The Model 450 is factory preset to 12 Set Serial Interface Baud Rate BAUD 0 BAUD 1 or BAUD 2 There are three settings for the type parameter 0 300 Baud 1 1200 Baud 2 9600 Baud Nothing Sets the Serial Interface Baud rate Serial Interface Baud Rate Query BAUD Returns current Serial Baud rate where 0 300 Baud 1 1200 Baud and 2 9600 Baud Set End Or Identify EOI Status END 0 Or END 1 Nothing Sets the EOI status 0 enabled 1 disabled When enabled the hardware EOI line becomes active with the last byte of a transfer The EOI identifies the last byte allowing for variable length data transmissions End Or Identify EOI Status Query END Current EOI status 0 EOI enabled 1 EOI disabled
111. our tinned wires are provided for connection to the Hall Generator The leads may be soldered directly to these wires G Wire Current to ESNIE Sensor Red Wire 6 Foot Cable to Gaussmeter Hall Voltage d Beare from Sensor Yellow Wire F 460 2 3 eps Figure 2 3 Model MCBL 6 User Programmable Cable Accessory CAUTION The Hall Generator should be isolated from all line voltages or voltages referenced to earth ground f not damage to the Model 450 Gaussmeter is almost a certainty Refer to Appendix C for a complete list of compatible Hall generators manufactured by Lake Shore Once connections are made refer to Paragraph C6 0 for instructions on using the Hallcall exe program to store probe parameters in the internal EPROM CORRECTED AND MONITOR ANALOG OUTPUTS Analog outputs are available on 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 is updated at the same rate as the display The Monitor output is a live analog signal proportional to the magnetic flux density waveform of the respective channel Refer to Paragraph 3 12 for further operational information INITIAL SETUP AND SYSTEM CHECKOUT PROCEDURE This procedure verifies basic unit operation before initial use for measurements CAUTION Check power source for proper voltage before connecting line cord to the
112. 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 force The voltage potential across the width of the conductor is called the Hall voltage This Hall voltage can be utilized in practice by attaching two electrical contacts to the sides of the conductor The Hall voltage can be given by the expression Vi yg B sin 8 where V Hall voltage mV Ya Magnetic sensitivity mV kG at a fixed current B Magnetic field flux density kilogauss 9 Angle between magnetic flux vector and the plane of Hall generator As can be seen from the formula above the Hall voltage varies with the angle of the sensed magnetic field reaching a maximum when the field is perpendicular to the plane of the Hall generator ACTIVE AREA The Hall generator assembly contains the sheet of semiconductor material to which the four contacts are made This entity is normally called a Hall plate The Hall plate is in its simplest form a rectangular shape of fixed length width and thickness Due to the shorting effect of the current supply contacts most of the sensitivity to magnetic fields is contained in an area approximated by a circle centered in the Hall plate whose diameter is eq
113. ps Figure C 6 Transverse Hall Generator HGT 3010 HGT 3030 and HGCT 3020 Dimensions Table C 1 Cryogenic Hall Generator Specifications Maximum continuous current 300 mA 300 mA non heat sinked Magnetic sensitivity lc nominal control 0 55 to 1 05 mV kG 0 55 to 1 05 mV kG current Maximum linearity error 1 0 RDG 30 to 30 kG 1 0 RDG 30 to 30 kG sensitivity vs field 12 0 RDG 150 to 150 KG 2 0 RDG 150 to 150 kG Zero field offset voltage I nominal 200 uV max 200 uV max control current Operating temperature range 4 2 K to 375K 4 2 K to 375 K sensitivity nominal control current 34 AWG copper w Teflon insulation Hall Generator C 5 Lake Shore Model 450 Gaussmeter User s Manual 0 50 11 0 125 in gt Center of Active Area A a SOOO DDO OOO 0 130 in max ye E lt EE max over 0 028 in max Hall plate over leads 9 5 in min C 421 C 7 eps Figure C 7 Transverse Hall Generator HGT 1010 Dimensions Table C 2 Axial Hall Generator Specifications HGA 3010 HGA 3030 Description Instrumentation quality axial low Instrumentation quality axial phenolic temperature coefficient phenolic package package Active area approximate 0 030 inch diameter circle 0 030 inch diameter circle Output resistance approximate Nominal control current Icy 100 mA 100 mA Maximum continuous current non 300 mA 300 mA heat sinked Magnetic sensiti
114. r OFF Refer to Paragraph 3 6 Gauss Tesla Changes display units from gauss to tesla Gauss G is used in the cgs system where 1 G 10 4 T Tesla T is used in the SI system where 1 T 104 G Refer to Paragraph 3 7 Relative Set With the relative feature turned ON this key captures the field reading as the relative setpoint or the user may enter a number via the keypad Works with the Relative On Off key Refer to Paragraph 3 8 Relative On Off 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 Refer to Paragraph 3 8 Alarm Set Sets high and low alarm points The alarm setpoints are absolute unsigned i e the positive or negative aspect of the field reading is ignored Refer to Paragraph 3 9 Alarm On Off Turns alarm feature ON or OFF After setting high and low alarm points with Alarm Set the alarm is activated whenever the magnetic field goes inside or outside the range defined regardless of the sign positive or negative of the reading Press and hold Alarm On Off to turn the alarm ON or OFF and select the alarm to sound inside or outside the range Refer to Paragraph 3 9 Local Selects local or remote operation When set to Local the unit responds to front panel controls When set to Remote the unit is controlled via the IEEE 488 Interface Remote users have the option to lock out front panel co
115. red the characteristics of the new probe are downloaded to the gaussmeter memory Normal operation may continue after the new probe offset is nulled using the Zero Probe operation If the instrument is powered up with no probe attached the following message is displayed 3 15 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 stem should never have force applied Any strain on the sensor may alter the probe calibration and excessive force may destroy the Hall generator CAUTION Care must be exercised when handling the probe The tip of the probe is very fragile Stressing the Hall sensor can alter its calibration Any excess force can easily break the sensor Broken sensors are not repairable Avoid repeated flexing of the stem of a flexible probe As a rule the stem should not be bent more than 45 from the base See Figure 3 4 Force should never be applied to the tip of the probe On all probes do not pinch or allow cables to be struck by any heavy or sharp objects Although damaged or severed cables should be returned to Lake Shore for repair please understand that probes are not always repairable When probes are
116. ress is used to compute the talk and listen addresses which identify the board or device on the Type of compare on EOS GPIB Valid primary addresses range EOS byte from O to 30 00H to 1EH Send EOI at end of Write Adding 32 to the primary address System Controller forms the Listen Address LA Assert REN whe SC Adding 64 to the primary address Enable Auto Serial Polling forms the Talk Address TA Enable CIC Protocol Bus Timing 500nsec EXAMPLE Selecting a primary address Parallel Poll Duration Default of 10 yields the following Use this GPIB board 10 32 42 Listen address Board Type 10 64 74 Talk address Base NO Address y F1 Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board National Instruments DEV12 Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address T Select the primary GPIB address by Secondary GPIB Address H using the left and right arrow keys Timeout setting This address is used to compute the Terminate Read on EOS talk and listen addresses which Set EOI with EOS on Writes Yes identify the board or device on the Type of compare on EOS 7 Bit GPIB Valid primary addresses range EOS byte from 0 to 30 00H to 1EH Send EOI at end of Write Yes Adding 32 to the primary address Enable Repeat Addressing Yes forms the Listen Address LA Adding 64 to the primary address forms the Talk Address TA EXAMPLE Selecting a primary address of 10 yields the following 10 32 42
117. river release the drawer holding the line voltage selector and fuse Slide out the removable plastic fuse holder from the drawer Rotate the fuse holder until the proper voltage indicator shows through the window Verify the proper fuse value D Zomm bk Wn gt Re assemble the line input assembly in the reverse order 9 Verify the voltage indicator in the window of the line input assembly 10 Connect the instrument power cord 11 Turn the line power switch On I 6 2 Service Lake Shore Model 450 Gaussmeter User s Manual Fuse Drawer Screwdriver Slot Line Cord Power Switch Input O Off I On Figure 6 1 Power Fuse Access 6 4 FUSE REPLACEMENT N LINE 10 5 Voltage 50 60 Hz 40 VA MAX FUSE DATA 100 120 V 0 5A 0 25 x 1 25 in T 220 240 V 0 25A 5 x 20 mm T F 450 6 1 eps Below is the procedure to remove and replace a line fuse There are two basic power configurations U S and International Units produced for use in the U S have a single fuse on the hot Units produced for International use have a double fuse for the hot and neutral To change line input from the factory setting use the appropriate fuse in the connector kit shipped with the instrument Test fuse with ohmmeter Do not rely on visual inspection of fuse WARNING To avoid potentially lethal shocks turn off gaussmeter and disconnect it from AC power before performing these procedures CAUTION For continued protec
118. ro 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 5 10 4502 Model 450 Gaussmeter User s Manual MCBL 6 Hall Generator Cable Assembly The MCBL 6 Cable Assembly connects a discrete Hall generator to the Model 450 Gaussmeter Cable is 2 meters 79 inches long The cable ships with the 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 Refer to Appendix C Accessories and Probes 5 1 Lake Shore Model 450 Gaussmeter User s Manual Accessories Continued MODEL NUMBER DESCRIPTION OF ACCESSORY MH XX Helmholtz Coils Provides stable low magnetic field when used with customer supplied power supply Often used to provide reference field to help check gaussmeter accuracy Three coils are available as follows Refer to Paragraph 5 3 MH 2 5 Helmholtz Coil 2 5 inch inner diameter field strength 30 G 1 A maximum continuous current 2 A coil resistance 3 Q See Figure 5 5 MH 6 Helmholtz Coil 6 inch inner diameter field strength 25 G 1 A maximum continuous current 2 A Coil Resistance 10 Q See Figure 5 6 MH 12 Helmholtz Coil 12 inch inner diameter field strength 12 G 1A maximum continuous current 2 A Coil Re
119. robe 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 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 the Enter key 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 450 accuracy 11 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 the Max Hold key to capture the highest reading CAUTION Take care when handling the probe its tip is very fragile Any excess force may break it NOTE Probe readings depend on the 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 Refer to Paragraph 3 15 Installation 2 5 Lake Shore Model 450 Gaussmeter User s Manual Initial Setup And System Checkout Procedure Continued 12 Carefully place probe in contact
120. s a Model MFT 3E03 type for general field measurements Once a stem or sensor has been damaged the probe is not repairable Metal enclosed probes such as the Model MMT 6J08 and MMA 2508 types offer the greatest amount of protection to the Hall sensor and therefore are the most rugged types Be cautious about using aluminum stemmed transverse probes such as the Model MMT 6J08 type where AC magnetic fields are to be measured Eddy currents in the stem material can affect reading accuracy superior choice for AC measurements would b the Model MNT 4E04 type fiberglass epoxy stem probes Several stem lengths are offered for each probe type User preferences or test 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 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 magnetic fields with a high gradient across the sensor width choose the smallest active area practical keeping in mind however the fragility rule in number 2 above Lake Shore gaussmeter probes exhibit different ranges of magnetic fields over which they will provide valid readings Check the specification sheet for these usable ranges High Stability probes such as those whose mode
121. s of carriers namely negative electrons and positive holes sensitivity The ratio of the response or change induced in the output to a stimulus or change in the input Temperature sensitivity of a resistance temperature detector is expressed as S dR dT setpoint The value selected to be maintained by an automatic controller serial interface A computer interface where information is transferred one bit at a time rather than one byte character at a time as in a parallel interface RS 232C is a common serial interface SI Syst me International d Unit s See International System of Units stability The ability of an instrument or sensor to maintain a constant output given a constant input Glossary of Terminology A 5 Lake Shore Model 450 Gaussmeter User s Manual susceptance In electrical terms susceptance is defined as the reciprocal of reactance and the imaginary part of the complex representation of admittance suscept ibility conduct ance susceptibility x Parameter giving an indication of the response of a material to an applied magnetic field The susceptibility is the ratio of the magnetization M to the applied field H x M H In both SI units and cgs units the volume susceptibility is a dimensionless parameter Multiply the cgs susceptibility by 47 to yield the SI susceptibility See also Initial Susceptibility and Differential Susceptibility As in the case of magnetization the susceptibility is often seen expressed
122. s sent the instrument responds to the last query received Type EXIT to exit the program NOTE The INPUT instruction accepts no commas as part of an input string If a comma appears in an instrument command replace it with a space REM INCLUDE c gpib pc qbasic qbdecl bas Link to IEEE calls CLS PRINT IEEE 488 COMMUNICATION PROGRAM PRINT CALL IBFIND dev12 DEV12 TERM CHR 13 CHR 10 INS SPACES 2000 INPUT ENTER COMMAND or EXIT CMD CMD UCASES CMD IF CMD EXIT THEN END CMD CMDS TERMS CALL IBWRT DEV12 CMDS CALL IBRD DEV12 IN ENDTEST INSTR IN CHRS 13 IF ENDTEST gt 0 THEN INS MIDS INS 1 ENDTEST 1 PRINT RESPONSE INS ELSE PRINT NO RESPONSE END IF GOTO LOOP2 Clear screen Open communication at address 12 Terminators are lt CR gt lt LF gt Clear for return string Get command from keyboard Change input to upper case Get out on Exit Send command to instrument Get data back each time Test for returned string String is present if lt CR gt is seen Strip off terminators Print return string No string present if timeout Get next command Remote Operation 4 5 Lake Shore Model 450 Gaussmeter User s Manual National Instruments GPIBO configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address T Select the primary GPIB address by Secondary GPIB Address A using the left and right arrow keys Timeout setting This add
123. seccececeeeeeeeeeaeceeeeeeesecacaeceeeeesesecaacaeeeeesesesensaaeeeeeess 3 6 3 4 Maximum Flexible Probe Bend Radius ssis atinsa aiaa aaa aaia aa aaaeaii aa 3 14 3 5 Probe Orientation For Positive Measurement cece cecccececeacesssceceeeeeceaaeeeeeeeeeeeeaueasaeeeeeseeaeanees 3 14 3 6 Effect Of Angle On Measurements rsrnnnnanuvnnnnnnnvrnnnnnsvrnnnensrrnnnensrrnnssnsrrnnnersrvnnsersrrnnsesrrnnsersrnnneenn 3 15 4 1 Typical National Instruments GPIB Configuration from IBCONF EXE rrnrrrrvrvnvrrvnvnnnrrvnrennrrenrrnnnnn 4 6 4 2 Serial Interface Adapters te a a k rde lidad dida 4 7 5 1 Definition of Lake Shore Transverse Probes occccccccccconncnconnnnnncononncnnnononcnonnnonnnnnnnnnnononnnrnnnnnnnnnonanos 5 4 5 2 Definition of Lake Shore Axial Probes cccccccccccesessseeceeeceanesseececeeeaeaaeaseceeeeaeeaseeseeeeeeaeananereeeees 5 5 5 3 Definition of Lake Shore Flexible Transverse Probe c cssscecccececeeseceeeceeeeeauessseeeeeeeeanaaeeeees 5 6 5 4 Definition of Lake Shore Gamma Probe sS r mmranervnrvnrannrsrsvnrnnrransnnrsrerverrnnnnnrarsrnevnnrnnsnerssernerrnnsnnre 5 7 5 5 Model MH 2 5 Helmholtz Col 5 8 5 6 Model MH 6 Helmholtz Col 5 9 5 7 Model MH 12 Helmholtz Col 5 9 5 8 Lake Shore Reference Magnet cccecceceeeeeeeeeeeeneeeeeeeneeeeeeueeeeeeueneeeeeaneeseceneeeeeeeeeeeeeeenaeees 5 10 5 9 Model 4060 Standard Zero Gauss Chamber 5 11 5 10 Model 4065 Large Zero Gauss Chamber 5 11 5 11 M
124. sed Front View Side View 12 2 mm 0 5 in diameter a II by 50 8 mm 2 in deep bore gt E 53 d 822mm 61 em 24 in gt 22 mm C450 5 9 eps Figure 5 9 Model 4060 Zero Gauss Chamber Front View 19 mm 0 75 in diameter opening 57 2 mm 2 25 in 31 8 mm 1 25 in 52 4 mm 2 1 in lt 304 8 mm 12 in lt Depth of Opening 279 4 mm 11 in Side View C450 510 eps Figure 5 10 Model 4065 Large Zero Gauss Chamber Accessories and Probes 5 11 Lake Shore Model 450 Gaussmeter User s Manual Cable Length 4 3 meters 14 feet C450 511 eps Figure 5 11 Model 4001 RJ 11 Cable Assembly 00000000000001 2000000000000 Ek say9ul Z Z WW GG A 43 mm gt 1 7 inches E 0 6 inches C450 512 eps Figure 5 12 Model 4002 RJ 11 to DB 25 Adapter O 000001 90000 O 0 6 inches C450 513 eps Figure 5 13 Model 4003 RJ 11 to DE 9 Adapter 5 12 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual a lt gt Note ee NOTE Customer must use 5 64 2 mm hex key to remove four existing screws from sides of instrument Unit on right side mounting shown Unit on left side also possible N Item Description P N Qty Se 6 1 Rack Mount Ear 107 440 1 e 2 Rack Mount Support 107 442 1 3 Rack Mount Panel 107 432 1 4 Rack Mount Handle 107 051 01 2 5 Screw 6 32 x 3 8 Inch 0
125. sistance 20 Q See Figure 5 7 MRA XXX Reference Magnets High quality reference magnets are available in transverse flat and MRT XXX axial round configurations Refer to Paragraph 5 4 and see Figure 5 8 MRA 312 100 Axial Reference Magnet 0 312 inch inside diameter 100 G 1 MRA 312 200 Axial Reference Magnet 0 312 inch inside diameter 200 G 1 MRA 312 300 Axial Reference Magnet 0 312 inch inside diameter 300 G 1 MRA 312 500 Axial Reference Magnet 0 312 inch inside diameter 500 G 1 MRA 312 1K Axial Reference Magnet 0 312 inch inside diameter 1 kG 1 MRA 312 2K Axial Reference Magnet 0 312 inch inside diameter 2 kG 1 MRT 062 200 Transverse Reference Magnet 0 062 inch gap 200 G 1 MRT 062 500 Transverse Reference Magnet 0 062 inch gap 500 G 1 MRT 062 1K Transverse Reference Magnet 0 062 inch gap 1 kG 0 5 MRT 062 2K Transverse Reference Magnet 0 062 inch gap 2 kG 0 5 MRT 062 5K Transverse Reference Magnet 0 062 inch gap 5 kG 0 5 MRT 062 10K Transverse Reference Magnet 0 062 inch gap 10 KG 5 MRT 343 50 Transverse Reference Magnet 0 343 inch gap 50 G 1 MRT 343 100 Transverse Reference Magnet 0 343 inch gap 100 G 1 MPEC XXX Probe Extension Cables Four cables are available Each extension cable contains a EEPROM for calibration data Each extension cable must be matched to a specific probe To maintain probe accuracy that probe and extension cable must be calibrated together at Lake Shore Th
126. smeter Electromagnetic Compatibility EMC of electronic equipment is a growing concern worldwide Emissions of and immunity to electromagnetic interference is now part of the design and manufacture of most electronics To qualify for the CE Mark the Model 450 meets or exceeds the generic requirements of the European EMC Directive 89 336 EEC 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 installed cabling may defeat even the best EMC protection For the best performance from any precision instrument follow the grounding and shielding instructions in the User s Manual In addition the installer of the Model 450 should consider the following e Leave no unused or unterminated cables attached to the instrument e Make cable runs as short and direct as possible e Do not tightly bundle cables that carry different types of signals Add the clamp on ferrite filter Part Number 109 053 included with the connector kit to the serial interface cable near the instrument rear panel when that interface is used Lake Shore Model 450 Gaussmeter User s Manual TABLE OF CONTENTS Chapter Paragraph Title Page 1 INTRODUCTION geseet ende Eege ee dee ees 1 1 1 0 Generali can at ee 1 1 1 1 Model 450 Gaussmeter Sy
127. st be at full amplitude for at least a few milliseconds 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 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 Orientation of the probe is not critical Once inserted press Zero Probe to display the screen above Press Enter to display the CALIBRATING message followed by a return to the normal display Do not move the probe while calibrating The probe is now zeroed For best results periodically zero the probe Operation 3 3 Lake Shore Model 450 Gaussmeter User s Manual 3 4 SELECT RANGE AND AUTO RANGE The Model 450 reads each Lake Shore probe type High Stability High Sensitivity or Ultra High Sensitivity These probes sense fields as low as 0 01 mG and as high as 300 KG The tables below list full scale rang
128. stem Description ooononccccnninocicnnococnnonononcnn nono ncnrnnno narran nn 1 2 1 2 Safety SUMMA Vicio tdi 1 5 1 3 Safety MIS iii A A A AE 1 5 2 INSTALLATION saa 2 1 2 0 ET 2 1 2 1 Inspection and Unpackimg nn aaa aaa ea a aae aeai a a 2 1 2 2 Repackaging For Shipment seerne a a aS ACA a E 2 1 2 3 Definition of Rear Panel Connections ooooccccococococcconocononononcnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnannnnes 2 2 2 4 Line Input AssemblY ssoicosiotinisca sienta tiras 2 3 25 Probe Input Connection vue ii a t ka ped ad 2 3 2 6 Corrected and Monitor Analog Outputs oooococonococccccccoconononcnnnnnnnnnnnononnnnnnnnnnnnnnnnnnnnnnnnnnnnnns 2 4 2 7 Initial Setup and System Checkout Procedure oocccccccococococccocccononononcnnnnncnnnnnnnoncnnnnnnnnnnnnes 2 4 3 OPERATION iii e a ii rd 3 1 3 0 Coi a A eee 3 1 3 1 Definition of Front Panel Controls oooooocccccccococococcconcnonononononnnnnnnnnnnnnnnonnnnnnnnnnn me nnnnnnnnnnnnnnnes 3 1 3 1 1 Front Panel Keypad Definitions arrrnnnonnrrnnnnnnrrnnnnnnrrnnnennrrnnsnnsrrnnsensrrnnsensrrnnsensrrnnsennnn 3 1 3 1 2 LS era pie katun aE A de wate elven katun kaka las netted kanna kast 3 3 3 2 Max Hold and Max Heset A 3 3 3 3 Zero Gite 3 3 3 4 Select Range and Auto Range o en a e a a narran 3 4 3 5 AC DC and Peak 3 5 3 6 Eltere A AE et ka eros 3 5 3 6 1 Display EEN 3 5 3 6 2 Field and Temperature Compensation oooooccccccncocococcncnnnnnnnoncnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnns 3 6
129. struments on the interface bus perform one or more of the interface functions of TALKER LISTENER or BUS CONTROLLER A TALKER transmits data onto the bus to other devices A LISTENER receives data from other devices through the bus The BUS CONTROLLER designates to the devices on the bus which function to perform The MPS performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is the digital computer which tells the MPS which functions to perform Below are Model 450 IEEE 488 interface capabilities e SH1 Source handshake capability e RL1 Complete remote local capability e DC1 Full device clear capability e DTO No device trigger capability e CO No system controller capability e T5 Basic TALKER serial poll capability talk only unaddressed to talk if addressed to listen e L4 Basic LISTENER unaddressed to listen if addressed to talk e SR1 Service request capability e AH1 Acceptor handshake capability e PPO No parallel poll capability EI Open collector electronics 4 1 1 Model 450 IEEE 488 Interface Settings If using the IEEE 488 interface set the IEEE Address and Terminators Press Address to display the screen to the right Press the A or V keys to increment or decrement the IEEE Address to the desired number Press Enter to accept new number or Escape to retain the existing number Pressing either Enter or Escape displays the Terminators screen below Press the A or W keys to cycle
130. tall operate or maintain the product in accordance with the printed instruction provided 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 specifications at the time of shipment The accuracy and calibration of this product at the time of shipment are traceable to the United States National Institute of Standards and Technology NIST formerly known as the National Bureau of Standards NBS FIRMWARE LIMITATIONS Lake Shore has worked to ensure that the Model 450 firmware is as free of errors as possible and that the results you obtain from the instrument are accurate and reliable However as with any computer based software the possibility of errors exists In any important research when using any laboratory equipment results should be carefully examined and rechecked before final conclusions are drawn Neither Lake Shore nor anyone else involved in the creation or production of this firmware can pay for loss of time inconvenience loss of use of the product or property damage caused by
131. ternal field and 2 serves as the flux return path Physical damage to the outer shell can cause a permanent change in the gap flux density Reference magnets should not be dropped or physically abused Magnets of this type can have magnetic reference values ranging from 100 G to 20 kG but the most widely used value is 1 kG Reference magnet 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 inches In reference magnets used for axial field probes Alnico V or VI is the usual magnet material charged to saturation and stabilized down to a particular value The same temperature coefficients hold true as in the transverse probe and the same care in handling must be observed This assembly uses concentric mu metal shield cans to protect the magnet from the effects of external magnetic field Axial reference magnets are available in values up to 2 kG with 500 G being the most widely used value When a probe is inserted completely through the access guide three distinct magnetic peaks will be observed on the gaussmeter One peak occurs as the probe enters the magnet a second and greater peak is observed as the midpoint is reached and a third smaller peak is read as the probe leaves the
132. the cable secure and prevents interference Refer to Paragraph 3 15 for additional probe considerations Installation 2 4 2 4 1 2 4 2 2 4 3 2 5 Lake Shore Model 450 Gaussmeter User s Manual LINE INPUT ASSEMBLY This section covers line voltage and fuse verification in Paragraph 2 4 1 power cord in Paragraph 2 4 2 and power switch in Paragraph 2 4 3 Line Voltage and Fuse Verification To verify proper line voltage selection look at the indicator in the window on the fuse drawer of the line input assembly Line voltage should be in the range shown in the specifications listed on the back of the instrument See Figure 2 2 If not change the line voltage selector per instructions in Paragraph 6 3 The fuse must be removed to verify its value refer to the procedure in Paragraph 6 4 Use slow blow fuses of the value specified on back of the instrument Power Cord The Model 450 includes a three conductor power cord Line voltage is present across the outer two conductors The center conductor is a safety ground and connects to the instrument metal chassis For safety plug the cord into a properly grounded three pronged receptacle Power Switch The power switch turns the instrument On and Off and is located in the line input assembly on the instrument rear When I is raised the instrument is On When O is raised the instrument is Off Power Switch Line Cord Input O Off On Fuse Drawer LINE _ 10 5 Volt
133. this product or its failure to work or any other incidental or consequential damages Use of our product implies you understand the Lake Shore license agreement and statement of limited warranty FIRMWARE LICENSE AGREEMENT The firmware in this instrument is protected by United States copyright law and international treaty provisions To maintain the warranty the code contained in the firmware must not be modified Any changes made to the code is at the user s risk Lake Shore will assume no responsibility for damage or errors incurred as result of any changes made to the firmware Under the terms of this agreement you may only use the Model 450 firmware as physically installed in the instrument Archival copies are strictly forbidden You may not decompile disassemble or reverse engineer the firmware If you suspect there are problems with the firmware return the instrument to Lake Shore for repair under the terms of the Limited Warranty specified above Any unauthorized duplication or use of the Model 450 firmware in whole or in part in print or in any other storage and retrieval system is forbidden SOFTWARE LICENSE AGREEMENT This software is protected by United States copyright law and international treaty provisions Lake Shore provides this software package and grants you the user of the software a non exclusive and non transferable right to use this software Unless as provided in this Agreement any attempt to sublicense lease rent assi
134. through the following Terminator choices CR LF LF CR LF and EOI To accept changes or the currently displayed setting push Enter To cancel changes push Escape Power down the Model 450 then power it up again to allow other devices on the IEEE 488 bus to recognize a new Address or Terminator setting Remote Operation 4 1 Lake Shore Model 450 Gaussmeter User s Manual 4 1 2 IEEE 488 Command Structure The Model 450 supports several command types These commands are divided into three groups 1 Bus Control Refer to Paragraph 4 1 2 1 a Universal 1 Uniline 2 Multiline b Addressed Bus Control 2 Common Refer to Paragraph 4 1 2 2 3 Interface and Device Specific Refer to Paragraph 4 1 2 3 4 1 2 1 Bus Control Commande A Universal Command addresses all devices on the bus Universal Commande include Uniline and Multiline Commande A Uniline Command Message asserts only a single signal line The Model 450 recognizes two of these messages from the BUS CONTROLLER Remote REN and Interface Clear IFC The MPS sends one Uniline Command Service Request SRQ REN Remote Puts the Model 450 into remote mode IFC Interface Clear Stops current operation on the bus SRQ Service Request Tells the bus controller that the Model 450 needs interface service A Multiline Command asserts a group of signal lines All devices equipped to implement such commands do so simultaneously upon command transmission T
135. tion against fire hazard replace only with the same fuse type and rating specified for the line for the line voltage selected Turn power switch Off O Remove instrument power cord ak WN gt 0 25 x 1 25 inches 5x20 mm 100 120 V 220 240 V 0 5 AT 250 V 0 25 AT 250 V Re assemble line input assembly in reverse order Verify voltage indicator in the line input assembly window Connect instrument power cord Turn power switch On I mp Am Service Locate line input assembly on the instrument rear panel See Figure 6 1 With a small screwdriver release the drawer holding the line voltage selector and fuse Remove existing fuse s Replace with proper Slow Blow fuse ratings as follows 6 3 Lake Shore Model 450 Gaussmeter User s Manual 6 5 REAR PANEL CONNECTOR DEFINITIONS PIN DESCRIPTION PROBE INPUT DA 15 Connector View looking at rear panel 1 2 3 4 5 6 7 8 9 C450 6 2 eps Figure 6 2 DA 15 PROBE INPUT Connector Details ANALOG OUTPUTS Corrected Monitor PIN DESCRIPTION o Co 1 Analog Output Center Conductor 2 Ground Connector Shell C450 6 3 eps Figure 6 3 Corrected and Monitor ANALOG OUTPUTS Connector Details SERIAL UO ee Be Serial In RxD Serial In RxD Serial Ground Serial Ground Serial Out TxD Serial Out TxD RJ 11 Receptacle C450 6 4 eps Figure 6 4 SERIAL I O RJ 11 Connector Details 6 4 Service Lake Shore
136. tion of Probe Terminology A Distance from tip of probe to center line of active area B Magnetic flux density vector for positive gaussmeter reading HST High Stability Probe HSE High Sensitivity Probe UHS Ultra High Sensitivity Probe Usable Full Scale Ranges Versus Probe Type HST 1 HST 2 HSE 1 UHS 1 300 G 300 G 300 mG Usable on 300 G Ranges 30 kG 30 kG 300kKG_ oe TRANSVERSE Cable length 6 6 feet 0 36 20 030 dia T A l Corrected Temperature Model No L T W A E Fa Type Accuracy Coefficient Max rea aterial Range 3 of rdg Calibration MMT 6J02 VH 2 0 125 MMT 6J04 VH 4 0 125 0 061 0 180 S DC MMT 6J08 VH 8 0 125 0 005 HSE 1 DC MMT 6J18 VH 18 0 125 MNT 4E02 VH 2 0 125 9 o45 0450 Ce MNT 4E04 VH 4 20 125 max 80005 0 150 0 040 MMT 6J02 VG 2 0 125 0 050 approx MMT 6J04 VG 4 0 125 0 061 MMT 6J08 VG 8 0 125 max HST 2 MMT 6J18 VG 18 0 125 MNT 4E02 VG 2 0 125 0 045 0 150 l DC max MNT 4E04 VG 4 0 125 0 005 10 to 0 25 dia 0 210 Stainless 400 Hz 2 to 15Kto MCT 3160 WN 60 0 05 20 010 _ 20 050 MST to0K6 350k Figure 5 1 Definition of Lake Shore Transverse Probes C450 5 1 eps 5 4 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual Corrected Accuracy Reading Op AXIAL Temp Coefficient Max
137. tion of the instrument Decimal display resolution specified as n digits has 10 possible display values A resolution of n and one half digits has 2 x 10 possible values measurement resolution The ability of an instrument to resolve a measured quantity For digital instrumentation this is often defined by the analog to digital converter being used A n bit converter can resolve one part in 2 The smallest signal change that can be measured is the full scale input divided by 2 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 RS 232C Bi directional computer serial interface standard defined by the Electronic Industries Association ElA The interface is single ended and non addressable scalar A quantity which has magnitude only and no direction in contrast to a vector semiconducting material A conducting medium in which the conduction is by electrons and holes and whose temperature coefficient of resistivity is negative over some temperature range below the melting point semiconductor An electronic conductor with resistivity in the range between metals and insulators in which the electric charge carrier concentration increases with increasing temperature over some temperature range Note Certain semiconductors possess two type
138. tus ESB Bit 5 When set indicates if one of the bits from the Standard Event Status Register has been set Paragraph 4 1 4 2 4 1 3 2 Standard Event Status Register and Standard Event Status Enable Register The Standard Event Status Register supplies various conditions of the Model 450 STANDARD EVENT STATUS REGISTER FORMAT E E Je ME TE Weighting 128 64 32 16 8 4 2 1 Bit Name Bits 2 and 6 are not used Reports of this register interrupt the user only if the bits are enabled in the Standard Event Status Enable Register and if bit 5 of the Service Request Enable Register is set The Standard Event Status Enable Register allows the user to enable any of the Standard Event Status Register reports The Standard Event Status Enable command ESE sets the Standard Event Status Enable Register bits Setting a bit of this register enables that function To set a bit send the command ESE with the sum of the bit weighting for each bit to be set Refer to the RESE command The Standard Event Status Enable Query ESE reads the Standard Event Status Enable Register ESR reads the Standard Event Status Register Once this register is read the bits reset to zero Remote Operation 4 3 Lake Shore Model 450 Gaussmeter User s Manual Power On PON Bit 7 Set to indicate a controller off on off transition Command Error CME Bit 5 Set to indicate a command error since the last reading Controller
139. ual to the plate width Thus when the active area is given the circle as described above is the common estimation Hall Generator C 1 Lake Shore Model 450 Gaussmeter User s Manual Ic Red gt lt Conventional Current force on electron VH gt Clear or Yellow VH Blue High Mobility IV Semiconductor a Indium arsenide b Gallium arsenide U Ic Green or Black C 421 C 1 eps Figure C 1 Hall Generator Theory C2 2 ORIENTATION 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 general field sensing El h r AM KLAG AAA Transverse DA B d Q amp DL Axial C 421 C 2 eps Figure C 2 Axial and Transverse Configurations C 2 Hall Generator C2 3 C2 4 C2 5 C3 0 Lake Shore Model 450 Gaussmeter User s Manual HANDLING CAUTION Care must be exercised when handling the Hall generator The Hall generator is very fragile Stressing the Hall generator can alter its output Any excess force can easily break the Hall generator Broken Hall generators are not repairable Hall Generators are very fragile and req
140. uire 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 POLARITY If the control current enters the red lead with l connected to the positive terminal of the current supply and the magnetic field direction is as shown in Figure C 2 a positive Hall voltage will be generated at the blue lead V Reversing either the current or the magnetic field will reverse the output voltage LEAD CONFIGURATIONS All Hall generators except Models HGCA 3020 and HGCT 3020 have 34 AWG solid copper with poly nylon insulation and have the same lead configuration as follows Red I Green Fig Input Control Current Blue Vy Clear Vy I 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 I Ge d Input Control Current Blue V Yellow SN Output Hall Voltage HALL GENERATOR GENERIC HOOKUP The Hall voltage leads may also be connected directly to a readout instrument such as a high impedance voltmeter or can be attached to electronic circuitry for amplification or conditioning
141. umber 3 on the numerical keypad and press Enter The unit places a maximum output of 3 0 kG into memory and displays the Min Output screen Enter the numbers 0 0 on the numerical keypad and press Enter The unit places a minimum output of 0 0 KG into memory Changes to the Corrected Analog Output are immediately observable For best results put at least 100 counts between minimum and maximum for the range For example if the 3 0000 KG range was selected with a minimum scale of 1 0000 KG enter a maximum setting of 1 0100 KG or greater 3 12 2 Monitor Analog Out 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 Most of the error is on lower ranges and results from zero offsets in the probe and instrument The error can be minimized by subtracting output voltage observed at zero field from the live output 3 12 3 Analog Output Control Mode It is sometimes convenient to use the corrected analog output as a control voltage output instead of an analog output proportional to measured field A set of computer interface commands control the digital to analog converter DAC for the corrected analog output One common application is using the output to program an electromagnet power supply By using the analog output the user can avoid p
142. un IBCONF to configure the GPIB PCII IIA board and dev 12 Set the EOS byte to OAH See the setup in Figure 4 1 IBCONF modifies gpib com oa fF wN e 7 Connect the instrument to the interface board and power up the instrument Verify address as 12 and terminators as CR LF 4 1 4 2 Running The Example QuickBasic Program Copy c gpib pc Qbasic qbib obj to the QuickBasic directory QB4 2 Change to the QuickBasic directory and type link q qbib obj bqlb4x lib where x 0 for QB4 0 and 5 for QB4 5 This one time only command produces the library file qbib qlb The procedure is found in the National Instruments QuickBasic readme file Readme qb 3 Start QuickBasic Type qb l qbib qlb Start QuickBasic in this way each time the IEEE interface is used to link in the library file 4 Create the IEEE example interface program in QuickBasic Refer to Table 4 1 Name the file ieeeexam bas and save 5 Run the program 4 4 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 1 5 Notes On Using the IEEE Interface To chain commands or queries together insert a semi colon between them Multiple queries cannot be chained The Model 450 responds to the last query entered when addressed as a talker Queries generally use the same syntax as an associated setting command followed by a question mark They most often return the same information that is sent Some queries have no command form Add a query to the end of
143. up to 5 digits and decimal point Place decimal appropriate to range Analog Out Low Setpoint Query ANOL XXX XX Returns sign up to five digits and decimal point Places decimal appropriate to range Remote Operation ANOLM Input Returned Remarks AOCON Input Returned Remarks Example AOCON Input Returned Remarks AUTO Input Returned Remarks AUTO Input Returned Remarks BRIGT Input Returned Remarks BRIGT Input Returned Remarks CODE Input Returned Remarks Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Analog Out Low Setpoint Multiplier Query ANOLM u m k Or _ Queries analog out low setpoint multiplier u micro x 1 1 000 000 m milli x 1 1 000 k kilo x 1 000 and _ Blank unity x 1 Set Analog Output Control Mode AOCON XXX XX Nothing Sets bipolar output voltage in percent of full scale Allows a resolution of 0 01 As a safety precaution this setting always equals zero if the instrument loses power or is turned off The setting cannot be changed from the front panel Refer to Paragraph 4 5 The command AOCON 50 25 sets output to 50 25 of full scale This is 5 025 volts for a 10 volt output or 1 5075 volts for a 3 volt output Analog Output Control Mode Query AOCON XXX XX Queries the unit for the current analog output control mode percentage of full scale reading The setting f
144. updating at 5 readings per second the filter settles in 1 6 seconds For 9 to 64 filter points an exponential algorithm is used for a smooth response The settling time for a 1 change to full display resolution is about the same as the Lake Shore Model 450 Gaussmeter User s Manual Exponential Response with Filter Points set to 9 Linear Response with Filter Points set to 8 Step Change in Magnetic Field Seconds 15 60 Readings 0 20 30 40 50 Figure 3 3 Display Filter Response Examples number of filter points in seconds For example a setting of 10 filter points settles in about 10 seconds Figure 3 3 illustrates the difference between linear and exponential response 3 6 2 Field and Temperature Compensation NOTE Unless there is a specific reason Lake Shore strongly advises customers not to turn field and temperature compensation off it may reduce reading accuracy substantially To disable Field and Temperature Compensation press and hold the Filter key for about 5 seconds to display the Field Compensation screen To improve accuracy all probes have a magnetic field compensation table stored in a PROM Turning Field Compensation OFF causes the Model 450 to ignore this table Press the A or V keys to cycle between ON and OFF Push Enter to accept the new setting or Escape to retain the old setting and return to the normal display If the probe has no field compensation the setting is ignored Some
145. urchasing a magnet supply controller and adding a separate interface to their computer The Model 450 software dated 10 1 94 and newer supports this feature Update older Model 450 software at no charge The actual output voltage and voltage resolution depends on an instrument hardware setting The Model 450 comes with standard 3 volt output or optional 10 volt output To upgrade from 3 volt output to 10 volt output consult the factory Output Range 3 volts 10 volts Resolution 0 37 mV 1 2 mV Two commands control the corrected analog output via the IEEE 488 or Serial Interface The ANOD command specifies interface control of the output set it to 2 Send this command only once The ANOD query confirms the change This setting will not change if the instrument is powered off but it can be changed back to normal operation from the front panel The AOCON command sets bipolar output voltage in percent of full scale The setting format of xxx xx allows for a sign and a resolution of 0 01 As a safety precaution this setting always equals zero if the instrument looses power or is turned off The setting cannot be changed from the front panel The AOCON query confirms the change Example Sending AOCON 50 25 sets output to 50 25 of full scale This is 5 025 V for a 10 V output or 1 5075 V for a 3 V output Operation 3 11 Lake Shore Model 450 Gaussmeter User s Manual 3 13 LOCKING AND UNLOCKING THE KEYBOARD The Model 45
146. ured field rises and falls its maximum value is held on the display Make note of the probe orientation at the maximum reading to identify the field orientation Lake Shore Logo Towards North Pole HE s 5 Deeg D Transverse Probe Orientation For Positive Measurement B gt NERE gt Axial Probe Orientation For Positive Measurement C 421 3 5 eps Figure 3 5 Probe Orientation For Positive Measurement 3 14 Operation Lake Shore Model 450 Gaussmeter User s Manual 3 15 4 Probe Accuracy Considerations NOTE Probe readings are dependent upon the angle of the sensor in relation to the magnetic field The farther from 90 the angle between the probe and the field the greater the percentage of error For example a 5 deviation causes a 0 4 error a 10 deviation causes a 1 5 error etc NOTE For best 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 The user must consider all the possible contributors to the accuracy of the reading Both the probe and gaussmeter have accuracy specifications that may impact the actual reading The probe should be zeroed before making critical measurements The zero probe function is used to null cancel out the zero offset of the probe or small magnetic fields It is normally used in conjunction with the zero gauss ch
147. ux The electric or magnetic lines of force in a region flux density B Any vector field whose flux is a significant physical quantity examples are magnetic flux density electric displacement and gravitational field gamma A cgs unit of low level flux density where 100 000 gamma equals one oersted or 1 gamma equals 10 oersted A 2 Glossary of Terminology Lake Shore Model 450 Gaussmeter User s Manual gauss G The cgs unit for magnetic flux density B 1 gauss 10 tesla 1 Mx cm line cm Named for Karl Fredrich Gauss 1777 1855 a German mathematician astronomer and physicist gaussian system units A system in which centimeter gram second units are used for electric and magnetic qualities general purpose interface bus GPIB Another term for the IEEE 488 bus gilbert Gb A cgs electromagnetic unit of the magnetomotive force required to produce one maxwell of magnetic flux in a magnetic circuit of unit reluctance One gilbert is equal to 10 47 ampere turn Named for William Gilbert 1540 1603 an English physicist hypothesized that the earth is a magnet gilbert per centimeter Practical cgs unit of magnet intensity Gilberts per cm are the same as oersteds Greek alphabet The Greek alphabet is defined as follows Alpha Q A lota 1 I Rho p P Beta B B Kappa K K Sigma o z Gamma Y r Lambda A A Tau T T Delta A Mu u M Upsilon v Y Epsilon E Nu v N Phi d Ru Zeta E Z Xi R E Chi p X Eta n H Omicron O
148. various functions on the keypad Each character is comprised of a 5 by 7 dot matrix See Figure 3 2 Units KG Alarm G mG Probe Orientation T DC Relative Remote DC Onl nly mT PK On On Field Reading uT RMS J Lo Lower row used for Max Hold MAX shown above and Relative Setpoint SP readings Also used for various on off messages C 450 1 2 eps 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 Refer to Paragraph 3 7 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 i e operates the same as DC Max In AC Peak operation Max Hold uses a hardware circuit to trap peaks in the Hall voltage In this mode the unit displays the magnitude of the actual peak of an impulse or event For best accuracy the event mu
149. vity I nominal 0 55 to 1 05 mV KG 6 0 to 10 0 mV kG control current Maximum linearity error sensitivity 11 RDG 30 to 30 kG 0 30 RDG 10 to 10 kG versus field 1 5 RDG 100 to 100 KG 1 25 RDG 30 to 30 KG Zero field offset voltage Ic nominal 50 uV max 75 uV max control current Operating temperature range 40 to 100 C 40 to 100 C Mean temperature coefficient of 0 005 C max 0 04 C max magnetic sensitivity Mean temperature coefficient of offset 0 4 uV C max 0 3 uV C max lc nominal control current Mean temperature coefficient of 0 15 C approx 0 18 C approx resistance Leads 34 AWG copper with poly nylon 34 AWG copper with poly nylon insulation insulation C 6 Hall Generator Lake Shore Model 450 Gaussmeter User s Manual Table C 3 Transverse Hall Generator Specifications HGT 1010 HGT 3010 HGT 3030 Description General purpose Instrumentation quality Instrumentation quality transverse 0 020 inch thick transverse low temperature transverse ceramic package coefficient ceramic package Active area approximate 0 040 inch diameter circle 0 040 inch diameter circle 0 040 inch diameter circle input resistance aprox Output resistance approx Nominal control current 100 mA 100 mA 100 mA len current non heat sinked Magnetic sensitivity lc 7 5 to 12 5 mV kG 0 55 to 1 05 mV kG 6 0 to 10 0 mV kG nominal control current Maxi
150. with reference 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 the Max Reset key After successfully completing this checkout procedure the unit is ready for normal operation 2 6 Installation Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 3 OPERATION 3 0 GENERAL This chapter covers aspects of Model 450 operation Front panel controls are defined in Paragraph 3 1 front panel functions in Paragraphs 3 2 thru 3 13 default settings in Paragraph 3 14 and probe handling considerations in Paragraph 3 15 Refer to Chapter 4 for remote operation IEEE 488 Serial 3 1 DEFINITION OF FRONT PANEL CONTROLS The front panel consists of two major sections the 21 front panel keys described in Paragraph 3 1 1 and the 2 row by 20 character vacuum fluorescent display described in Paragraph 3 1 2 3 1 1 Front Panel Keypad Definitions Max Reset Works with Max Hold function Returns Max reading to normal field reading Refer to 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 Refer to Par
151. y SNUM XXXXXXXXXX Queries probe serial number The latest probe serial number format is HXXXXX though there is room for up to a ten character response Set Temperature Compensation Status TCOMP 0 or TCOMP 1 Nothing Turns set temperature compensation On or Off 0 Off 1 On If off probe temperature compensation if present is ignored Temperature Compensation Query TCOMP 0ori Queries temperature compensation status 0 Off 1 On If off probe temperature compensation if present is ignored Probe Type Query TYPE 0 1 0r2 Queries probe type 0 high sensitivity 1 high stability 2 ultra high sensitivity 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 Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 5 ACCESSORIES AND PROBES 5 0 GENERAL This chapter provides information on the accessories and probes available for the Model 450 Gaussmeter Model numbers are detailed in Paragraph 5 1 accessories in Paragraph 5 2 Lake Shore standard probes in Paragraph 5 3 Helmholtz coils in Paragraph 5 4 and reference magnets in Paragraph 5 5 5 1 MODELS The list of Model 450 Model numbers is provided as follows Model Description 450 Standard Model 450 Gaussmeter Features 3 volt corrected analog output 450 10 Optional Model 450 Gaussmeter
152. y to display the screen to the right Press the Analog Out A or V key to cycle the arrow gt to Def Default Press Enter to set the Corrected Analog Output for 3V 3 kG The user may also change Corrected Analog Output scaling User defined scaling can improve resolution over a selected area For example below is a symmetrical scaling similar to the default scale i 0 kG Reding 1 5kG 1 KG 0 5kG 0 5 KG 1 KG 1 5 KG Wollege 3 V 2V 1V 1V 2 V 43 V OV To enter this scale press Analog Out Press the Analog Out A or Y key to cycle the arrow gt to User as shown Press Enter to display the Max Output screen Enter the numbers 1 5 on the numerical keypad and press Enter The unit places a maximum output of 1 5 kG into memory and displays the Min Output screen Enter the numbers 1 5 on the numerical keypad and press Enter The unit places a minimum output of 1 5 kG into memory Changes to the Corrected Analog Output are immediately observable The example below is an asymmetrical scaling which demonstrates the versatility of user selectable scaling i 1 5 KG ed O KG 0 5 KG 1 KG 2 KG 2 5 KG 3 KG Output Voltage 3 V 2 V 1 V ae 1V 2 V 3 V To enter this scale press Analog Out Press the Analog Out A or V key to cycle the arrow gt to User as shown 3 10 Operation Lake Shore Model 450 Gaussmeter User s Manual Press Enter to display the Max Output screen Enter the n

Model 450 Gaussmeter User`s Manual, 2002

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