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Model 450 - Lake Shore Cryotronics, Inc.
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1. LSCI Model 4003 RJ 11 to DE 9 Adapter LSCI Model 4001 RJ 11 To customer supplied Cable Assembly 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 C 450 4 4 eps Figure 4 4 Serial Interface Adapters Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 2 2 Hardware Support The Model 450 interface hardware supports the following features Asynchronous timing is used for the individual bit data within a character This timing requires start and stop bits as part of each character so the transmitter and receiver can resynchronized between each character Half duplex transmission allows the instrument to be either a transmitter or a receiver of data but not at the same time Communication speeds of 300 1200 or 9600 Baud are supported The Baud rate is the only interface parameter that can be changed by the user Hardware handshaking is not supported by the instrument Handshaking is often used to guarantee that data message strings do not collide and that no data is transmitted before the receiver is ready In this instrument appropriate software timing substitutes for hardware handshaking User programs must take full responsibility for flow control and timing as described in Paragraph 4 2 5 4 2 3 Character Format A character is the smallest piece of inform
2. SCH 8 oy i p Refer to Pa E Installation L Procedure Ce 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 18 eps Figure 5 18 Model RM 2 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 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
3. 233 Banana Jacks un Input E 1 e 3 5 lt _ 5 4 P 450 5 09 bmp P 450 5 10 bmp Figure 5 10 Model MH 12 Helmholtz Coil Accessories and Probes 5 9 5 5 5 10 Lake Shore Model 450 Gaussmeter User s Manual 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 and have nominal temperature coefficients of about 0 0296 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 external 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 hav
4. R 10sec h GPIB Address IV Terminate Read on EOS Sen Primary IV Set EDI with EOS on Write nz z Se 1sec Y Properties Refresh H T amp bt EOS Compare Secondary NONE gt fi 0 EOS Byte v Readdress Figure 4 2 DEV 12 Device Template Configuration 4 6 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 1 4 2 Visual Basic IEEE 488 Interface Program Setup This IEEE 488 interface program works with Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better It assumes your IEEE 488 GPIB card is installed and operating correctly refer to Paragraph 4 1 4 1 Use the following procedure to develop the IEEE 488 Interface Program in Visual Basic 1 Start VB6 2 Choose Standard EXE and select Open 3 Resize form window to desired size 4 On the Project Menu select Add Module select the Existing tab then navigate to the location on your computer to add the following files Niglobal bas and Vbib 32 bas 5 Add controls to form a Add three Label controls to the form b Add two TextBox controls to the form c Add one CommandButton control to the form 6 Onthe View Menu select Properties Window 7 Inthe Properties window use the dropdown list to select between the different controls of the current project iw IEEE Interface Program LL ES 10 Set the properties of th
5. Remote Operation 4 1 4 1 2 1 4 2 Lake Shore Model 450 Gaussmeter User s Manual Changing IEEE 488 Interface Parameters Two interface parameters address and terminators must be set from the front panel before communication with the instrument can be established Other interface parameters can be set with device specific commands using the interface Paragraph 4 3 Press Address to display the following screen Select With AT IEEE Address 12 Press the A or W keys to increment or decrement the IEEE Address to the desired number Valid addresses are 1 thru 30 Default is 12 Press Enter to accept new number or Escape to retain the existing number Pressing either Enter or Escape displays the Terminators screen Select With A IEEE Term Cr Lf Press the A or V keys to cycle 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 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 Device Specific Refer to Paragraph 4 1 2 3 4 Message S
6. 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 This 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 Dn 5 o m O D rn Xx cldle x o v wi 3 3 x 7 b j elo ce alB o 2 2 2 25 2 25 o oj o o o ololo l g 2 2 5 0 oj oo l olo ool S 2 o o 2 O o 2 2 o o olo g jo lol o lol2 Jo o o o 5 Ooj z zi r x c Oiz o m m icj oj mm o m re x lt Je 14 a o N e Iv iu A l o 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 _ D
7. RJ 11 Receptacle C450 6 4 eps Figure 6 4 SERIAL I O RJ 11 Connector Details 6 4 Service 6 5 1 Service 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 Lake Shore Model 450 Gaussmeter User s Manual 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 PIN SYMBOL OO OO Joo ob ch IEEE 488 INTERFACE SH1 AH1 T5 L4 SR1 RL1 PPO DC1 DTO CO E1 11 10 9 8 7 6 5 4 3 2 1 23 22 21 20 19 18 17 16 15 14 13 C450 6 5 eps 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 T
8. EXAMPLE Selecting a primary address of 10 yields the following A 10 32 42 Listen address 10 64 74 Talk address Fl Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board IBCONF EXE eps Figure 4 3 Typical National Instruments GPIB Configuration from IBCONF EXE Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Table 4 3 Quick Basic IEEE 488 Interface Program IEEEEXAM BAS EXAMPLE PROGRAM FOR IEEE 488 INTERFACE This program works with QuickBasic 4 0 4 5 on an IBM PC or compatible The example requires a properly configured National Instruments GPIB PC2 card The REM SINCLUDE statement is necessary along with a correct path to the file QBDECL BAS CONFIG SYS must call GPIB COM created by IBCONF EXE prior to running Basic There must be QBIB QBL library in the QuickBasic Directory and QuickBasic must start with a link to it All instrument settings are assumed to be defaults Address 12 Terminators lt CR gt lt LF gt and EOI active To use type an instrument command or query at the prompt The computer transmits to the instrument and displays any response If no query is sent the instrument responds to the last query received Type EXIT to exit the program REM INCLUDE c gpib pc qbasic qbdecl bas Link to IEEE calls CLS Clear screen PRINT IEEE 488 COMMUNICATION PROGRAM PRINT CALL IBFIND dev12 DEV12 Open communication at address 12 TERMS CHR 13 C
9. F ANOL Define Analog Out Low Setpoint SH ANOL Analog Out Low Setpoint Query Command Name Brief Description of Function 4 3 1 Command List Structure 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 v is dependent on type of probe installed There Explanation and definition o are four ranges possible for each probe where 0 returned data is the highest and 3 is the lowest range 4 22 Remote Operation 4 3 2 CLS Input Returned Remarks ESE Input Returned Remarks Example ESE Input Returned Remarks ESR Input Returned Remarks xIDN Input Returned Remarks xOPC Input Returned Remarks xOPC 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 bit weighting 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 fl
10. For 9 to 64 filter points an exponential algorithm is used for a smooth response The settling time for a 1 change to 0 10 20 30 40 50 60 full display resolution is Figure 3 3 Display Filter Response Examples Readings about the same as the 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 Seconds 15 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 W 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 high sensitivity probes also feature temperature compensation Turning Temperature Compensation OFF causes the Model 450 to ignore this data 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
11. Lake Shore Model 450 Gaussmeter User s Manual 0 50 in 10 in min 0 125 in Center of dz Active Area SoS So R SEES 0 130 in max ERN SE Ss AXA max over H in max Hall plate over leads C 421 C 7 eps Figure C 7 Transverse Hall Generator HGT 1010 Dimensions Table C 2 Axial Hall Generator Specifications Description Instrumentation quality axial low Instrumentation quality axial phenolic temperature coefficient phenolic package package Maximum continuous current non 300 mA 300 mA heat sinked Magnetic sensitivity Ic nominal 0 55 to 1 05 mV kG 6 0 to 10 0 mV kG control current Maximum linearity error sensitivity 1 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 40 to 100 C 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
12. User s Manual Model 450 Gaussmeter E1 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 8 P N 119 005 13 September 2005 Lake Shore Model 450 Gaussmeter User s Manual LIMITED WARRANTY STATEMENT WARRANTY PERIOD ONE 1 YEAR 1 Lake Shore warrants that this Lake Shore product the Product will be free from defects in materials and workmanship for the Warranty Period specified above the Warranty Period If Lake Shore receives notice of any such defects during the Warranty Per
13. 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 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 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 14 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 15 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 Figur
14. eee nnne 3 3 Display Filter Response Examples nennen nennen ener enne 3 6 Maximum Flexible Probe Bend Hacdus nennen nnn 3 14 Probe Orientation For Positive Measurement ene 3 14 Effect Of Angle On Measurements nennen enne een sinn enne en 3 15 GPIB Setting Configuration essesssissieseseseseeeesee ee enne entem nennen nnns atn nasi nete snas sinn ni nannten 4 6 DEV 12 Device Template Configuration esses ener enne nnne 4 6 Typical National Instruments GPIB Configuration from IBCONE ENEE 4 11 Serial Interface AGapters ccccccsesceceecceceseeeesaceenecaeeaeeeeaaesaaaessaaeeeaeesseaaessaaaesnaeeseaaeseaaesseaaeenags 4 14 Definition of Lake Shore Gamma Probe sse enne enne nnne nnns ens 5 4 Definition of Lake Shore Robust Brass Stem Transverse Probes essesseeseeeeseeereeereeree ere 5 4 Definition of Lake Shore Transverse Probes sse enne nennen nennen 5 5 Definition of Lake Shore Tangential Probe c ccccsceeeeeceeeeeeeaeeeeeeeeeeeeeseaeeeeaaeseeeeeseeeesaeeeeneeeeaes 5 5 Definition of Lake Shore Axial Probes enne enne nennen 5 6 Definition of Lake Shore Flexible Transverse Probes sse 5 7 Definition of Lake Shore Flexible Axial Probe sesssssssseseeeeeeennen nnnm 5 7 Model MH 2 5 Helmholtz Col 5 8 Model MH 6 Helmholtz Col 5 9 Model MH 12 Helmholtz Col 5 9 Lake Shore Reference Magnets eene nnne enne nnns nnne renis 5 10 Model 4060 Standard Zero Gauss Chamber 5 11
15. v Max Max Zero Select Auto Relative Alarm Analog j Reset Hold Probe Range Range On On Off Out Enter 450_Front bmp Figure 1 1 Model 450 Gaussmeter Front Panel Introduction Lake Shore Model 450 Gaussmeter User s Manual 1 2 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 1 o o Gauss U Range AC or DC Range AC or DC wi Filter off DC Filter On wi Filter off DC Filter On High Sensitivity Probe HSE Tesla Gauss Resolution Resolution Range AC or DC Range AC or DC wi Filter oft DC Filter On wi Filter oft DC Filter On Ultra High Sensitivity Probe UHS Tesla 1 Gauss Range AC or DC Range AC or DC wi Filter off DC Filter On wi Filter off DC Filter On 0 001 G 0 0001 G 50 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
16. 0 32 dia min working space Transverse 0 062 gap MRT 062 200 within 1 of nominal value MRT 062 500 within 1 of nominal value Axial 0 312 diameter working space MRT 062 1K within 0 5 of nominal value MRA 312 2K within 1 of nominal value MRT 062 2K within 0 5 of nominal value MRA 312 1K within 1 of nominal value MRT 062 5K within 0 596 of nominal value 3 96cm 5 6 cm 1 56 O D 8 19 0 79 cm 0 31 dia min working space Axial 0 312 diameter working space Center line of magnet MRA 312 100 within 1 of nominal value is center of gap MRA 312 200 within 1 of nominal value Transverse 0 062 gap MRA 312 500 within 196 of nominal value MRT 062 10K within 0 596 of nominal value P 450 5 11 bmp Figure 5 11 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 Verity VS250 Data Devices PF211 or equivalent may be used Front View Side View 12 2 mm 0 5 in diameter T by 50 8 mm 2 in deep bore T n 53 22mm 61 mm 24 in 1 3 in J 4060_Chamber eps Figure 5 12 Model 4060 Zero Gauss Chamber Front View 19 mm 0 8
17. 4 Set Front Panel Keyboard Lock Code CODE XXX Nothing Sets front panel keyboard lock code Default 123 Enter any three numbers 4 29 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 30 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 0or FAST 1 Nothing Sets Fast Data 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 00r1 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 Pl
18. Command1 Name cmdSend Caption Send Default True Form1 Name frmSerial Caption Serial Interface Program Timer1 Enabled False Interval 10 12 Add code provided in Table 4 6 a Inthe Code Editor window under the Object dropdown list select General Add the statement Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend Click as shown in Table 4 6 c In the Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form Load Add the code to this subroutine as shown in Table 4 6 d Double Click on the Timer control Add code segment under Private Sub Timer1 Timer as shown in Table 4 6 e Make adjustments to code if different Com port settings are being used 13 Save the program 14 Run the program The program should resemble the following Serial Interface Program ioj ES Type exit to end program Command Response 15 Type in a command or query in the Command box as described in Paragraph 4 2 7 3 16 Press Enter or select the Send button with the mouse to send command 17 Type Exit and press Enter to quit 4 18 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Table 4 6 Visual Basic Serial Interface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Cl
19. M H and B H 4x 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 Lake Shore Model 450 Gaussmeter User s Manual Table B 2 Recommended SI Values for Physical Constants e naO ce soe et van Tsar o 0 0073 Fine Structure Constant pOce2 2h 137 0360 Elementary Charge UNE t 1 6022 x 10 C 6 6262 x 107 J Hz Plank s Constant Bats 1 0546 x 10 J s Avogadro s Constant s Constant 6 0220 x 107 mol Atomic Mass Unit 1u NEN 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 h 2e 2 0679 x 10 Wb Magnetic Flux Quantum 4 1357 x 107 J Hz C 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 RS O 1 0974 x 10 m Proton Moment in Nuclear Magnetons 2 7928 Bohr Magneton Us eh 2me 9 2741 x 10 JT Proton Gyromagnetic Ratio 2 6752 x 109 s T Diamagnetic Shielding Factor Spherical H2O Sample 1 o H2O0 1 0000 Molar Mass Constant pn O O 8 3144 J mol K Molar Volume Ideal Gas To 273 15K po 1 atm Vm RTo po 0 0224 m mol Boltzman Constant k R NA 1 3807 x 10 J K Ste
20. Refer to Chapter 5 for rear panel connector pin out details Lica WARNING 100 120 V VO USER SERVICE ABLE P PARTS ee ES EEN mA i SERVICING T RAINED Lu LULU Fa U ka JEDE i MERE jm 6 Monitor SERIAL WO 6 PROBE INPUT mmm 6 22 d POWER OFF TO MATE E 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 off switch and the fuse drawer The line cord connects to the power line jack The on off switch controls power to the unit The I symbol shows when power is on and the O shows when power is off The fuse drawer has a dual purpose housing the fuse and setting unit input power 3 Serial I O Connector The Serial UO Input Output Connector accepts the standard RJ 11 telephone conne
21. 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 Status Byte Register This status register contains important operational information from the unit requesting service The SPD command ends the polling sequence Common Commands Common Commands are addressed commands which create commonalty between instruments on the bus All instruments that comply with the IEEE 488 1987 standard share these commands and their format Common commands all begin with an asterisk They generally relate to bus and instrument status and identification Common query commands end with a question mark Model 450 common commands are detailed in Paragraph 4 3 Device Specific Commands 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 Model 450 device specific commands are detailed in Paragraph 4 3 Message Stri
22. T tesla Remote Operation 4 33 Lake Shore Model 450 Gaussmeter User s Manual 4 3 5 Probe Specific Commands 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 34 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 o orl Queries field compensation status 0 Off 1 On If Off probe field compensation table if present is ignored Probe Serial Number Query 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 Of 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 Oorl 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
23. 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 require delicate handling The ceramic substrate used to produce the Hall Generator is very brittle Use the leads to move the Hall generator Do not handle the substrate The strength of the lead to substrate bond is about 7 ounces so avoid tension on the leads and especially avoid bending them close to the substrate The Hall Generator is also susceptible to bending and thermal stresses POLARITY If the control current enters the red lead with I 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 lc Green Je Blue zu Clear V4 Input Control Current Output Hall Voltage
24. 4 2 8 Troubleshooting eite RR E e er 4 21 4 3 IEEE 488 Serial Interface Command Gummar sse 4 22 4 3 1 Command BEE te EE 4 22 4 3 2 eu ei Bet elle EE 4 23 4 3 3 Interface Command icti eigo a ede Eege dE de 4 25 4 3 4 Device Specific Commande AAA 4 26 4 3 5 Probe Specific Commands nessies a e aa e ea e N 4 34 5 ACCESSORIES AND PROBES neuen etit ec Boereeiiedee DeL lodo eigen aiii cus era sd toan lir elasde ice ka cese eso ciue nU 5 1 5 0 aerietal mue reiten De OE EIER EEG MM 5 1 5 1 Models 5 5 mendo E beet e ent ebbe ee ie race ratore e eerte ea tad 5 1 5 2 AGCCOSSOMNOS E 5 1 5 3 Lake Shore Standard Probes uk e de eie i im de er ree Lg o decipere Rete 5 3 5 3 1 Probe Selection Criteria EE 5 3 5 3 2 Radiation Effects on Gaussmeter PDrobes AA 5 3 5 3 3 Probe Specifications 2 1 tain icm eeu ere lili sie 5 4 5 4 Helmholtz Coil Low Field Standards AA 5 8 5 5 Reference Magnets eei mede bo o e ibi ete ais eee etn di 5 10 Ee E T A E E E AA 6 1 6 0 General A TE ET T A TE 6 1 6 1 General Maintenance Precautions nnne nnnnn nennen nnne nnn nnne 6 1 6 2 Electrostatic Discharge gere ete bec eet ee que eris 6 1 6 3 Line Voltage Selection s ete eire reae Ere re hace ct eine re Pra e ERE Raas Es 6 2 6 4 STEE E EE 6 3 6 5 Rear Panel Connector Definitions AAA 6 4 6 5 1 IEEE 488 Interface Connector essssssssssseseeseseenee nennen nennen entere enne nter
25. 488 Interface Board Installation for Visual Basic Program This procedure works for Plug and Play GPIB Hardware and Software for Windows 98 95 This example uses the AT GPIB TNT GPIB card 1 Install the GPIB Plug and Play Software and Hardware using National Instruments instructions 2 Verify that the following files have been installed to the Windows System folder a gpib 32 dll b gpib dll c gpib32ft dll Files b and c will support 16 bit Windows GPIB applications if any are being used 3 Locate the following files and make note of their location These files will be used during the development process of a Visual Basic program a Niglobal bas b Vbib 32 bas NOTE If the files in Steps 2 and 3 are not installed on your computer they may be copied from your National Instruments setup disks or they may be downloaded from www ni com 4 Configure the GPIB by selecting the System icon in the Windows 98 95 Control Panel located under Settings on the Start Menu Configure the GPIB Settings as shown in Figure 4 1 Configure the DEV12 Device Template as shown in Figure 4 2 Be sure to check the Readdress box Remote Operation 4 5 Lake Shore Model 450 Gaussmeter User s Manual System Properties General Device Manager Hardware Profiles Perform AT GPIB TNT Plug and Play Properties HES View devices by type C View devices by coi m Computer si Zi CDROM A E Disk drives bi ia Display adapters H 6 Floppy disk controlle
26. ALARM 0 Or ALARM 1 Nothing Sets the alarm function 0 Off 1 On Alarm Query ALARM Oorl 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 Of ALMB 1 Nothing Sets the audible alarm status 0 Off 1 On Audible Alarm Query ALMB Oorl Queries 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 mag
27. Accuracy Probe Dependent IEEE 488 Capabilities Complies with IEEE 488 2 SH1 AH1 SR1 RL1 PPO DC1 DTO CO 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 1 3 Lake Shore Model 450 Gaussmeter User s Manual Specifications Continued Front Panel Display Type 2 line by 20 characters vacuum fluorescent Units kG Alarm Probe Orientation mG Relative Remote T DC DC Only mT PK Field Reading uT RMS s Lower row used for Max Hold MAX shown above and Relative E Setpoint SP readings Also used for various on off messages C 450 1 2 eps Display Resolution 434 digit 534 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 deep 8 5 x 3 5 x 12 5 inches half rack package Weight 3 kilograms 6 6 pounds Introduction 1 3 1 4 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 precautio
28. B these ultra high sensitivity probes Resolutions of several gammas 10 G to tens of gammas are available depending on the mating gaussmeter r Application is optimum when fields are homogeneous over lengths greater gt Active Sensing Length 3 125 Cable Length 6 6 feet i SEN Ke eet W than 1 foot The active sensing length of the gamma probe is 3 125 inches Active Volume Corrected Operating Temperature Coefficient Model No W TIT ATL Type Accuracy Temperature Maximum ofReading Range Calibration 0 25 wl awl DC 10 to 40 5 to 0 C to o MLA 5006 HJ doghe CAS d pee 1mG C 0 02 C Gamma eps Figure 5 1 Definition of Lake Shore Gamma Probe ROBUST BRASS STEM TRANSVERSE PROBES 2 9 T 7 L E C0 QA N 0 20 dia T 0 37 dia max Corrected Operating Temperature Coefficient Model Active Stem Frequency f N L S W T A Area Material Type Accuracy Temperature maximum e 96 of Reading Range Zero Calibration 0 25 to E T 30kG 0 09 G C x0 01590 C 0 C to Brass DC 75 C 0 15 to Cl op 30 kG 0 13 G C 0 005 C Brass Transverse eps Z7 A Cable Length 6 6 feet MMTB 8 6J08 VG 0 125 Figure 5 2 Definition of Lake Shore Robust Brass Stem Transverse Probes MMTB 2 E MMTB 4 6J04 VH 0 125 6J08 VH 0 125 0 22 0 061 0 150 MMTB 2 max 6J04 VG lat l n 5 4 Accessories an
29. Baud Use the following procedure to develop the Serial Interface Program in Quick Basic Start the Basic program Enter the program exactly as presented in Table 4 7 Adjust the Com port and Baud rate in the program as necessary Lengthen the TIMEOUT count if necessary Save the program Run the program Type a command query as described in Paragraph 4 2 7 3 Type EXIT to quit the program Oo oll noU een eor I ce Table 4 7 Quick Basic Serial Interface Program 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 O 7 1 RS FOR RANDOM AS 1 LEN 256 LINE INPUT ENTER COMMAND or EXIT CMDS Get command from keyboard CMD UCASES CMDS Change input to upper case IF CMD 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 TIMEOUT AND INSTR RS TERMS 0 Wait for response INS INPUTS LOC 1 1 Get one character at a time IF INS THEN N N 1 ELSE N 0 Add 1 to timeout if no chr RSS RSS INS Add next chr to string WEND Get chrs until terminators IF RS lt gt THEN See if return string is empty RS MIDS RSS 1 INSTR RS TERMS
30. Commands in Paragraph 4 3 3 Device Specific Commands in Paragraph 4 3 4 and Probe Commands in Paragraph 4 3 5 Command Function Command Function Page 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 Set 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 RIET Display Filter Query ADDR Set Address FNUM Set Filter Points ADDR Address Query FNUM Filter Points Query BAUD Set Serial Interface Baud Rate FWIN Set Filter Window FWIN Filter Window Query Siak Serial Interface Baud Rate Query LOCK Set Keyboard Lock Status END EOI Query LOCK Keyboard Lock Query MODE Remote Mode MAX Set Max Hold Status MAX Max Hold Query 2 MODE Remote Mode Query MAXC Initiate Max Clear Re
31. Heg 4n x 10 mol Molar susceptibility cm mol emu mol an x ae REN Permeability u dimensonles 4m x 10 H m Wh A m Relative permeability ae not defined IERESCSEN dimensionless Volume energy density Ww 3 10 E 8 weber Wb volt 10 1 P x H M m u u 1 3 energy product erg cm 10 J m Demagnetization factor dimensionless NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 4nM F M l M Kp r N b Multiply a number in Gaussian units by C to convert it to SI e g 1 G x 10 T G 10 T c 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 po H M where to uo 4n x 10 H m The lower one is not recognized under SI and is based on the definition B oH J where the symbol is often used in place of J d 1 gauss 10 gamma y eges in terms of base units e Both oersted and gauss are expressed as cm f A m was often expressed as ampere turn per meter when used for magnetic field strength g Magnetic moment per unit volume h The designation emu is not a unit i Recognized under SI even though based on the definition B poH J See footnote c j Us p p 1 x all in SI p is equal to Gaussian p k BeH and ua H have SI units J m
32. 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 It 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 3 6 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 4 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 changes 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 W keys to toggle between ON and OFF Press
33. Or ede Introduction 1 5 1 6 Lake Shore Model 450 Gaussmeter User s Manual This Page Intentionally Left Blank Introduction Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 2 INSTALLATION 2 0 GENERAL 2 1 2 2 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 carrier and insurance company and notify Lake Shore Notify Lake Shore immediately of any missing parts Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment Refer to the standard Lake Shore Warranty on the A Page immediately behind the title page REPACKAGING FOR SHIPMENT To retu
34. The Model HGCA 3020 and HGCT 3020 Hall generators have 34 AWG stranded copper with Teflon insulation and have the following lead configuration Red ze Black l Blue Vj Yellow Mu Output Hall Voltage E Input Control Current 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 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
35. 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 Address and Terminators Press Address to display the screen to the right Press the A or W keys to 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 V keys to cycle through the following IEEE 488 Terminator choices CrLf Carriage Return and Line Feed Lf Cr Line Feed and Carriage Return LF Line Feed EOI End Or Identify Terminators are fixed to Cr Lf for the Serial Interface 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 ex
36. Type Exit and press Enter to quit 4 8 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Table 4 2 Visual Basic IEEE 488 Interface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Click gSend True End Sub Routine to handle Send button press Set Flag to True Private Sub Form Load Dim strReturn As String Dim term As String Dim strCommand As String Dim intDevice As Integer frmIEEE Show term Chr 13 amp Chr 10 strReturn Call ibdev 0 12 0 T10s 1 amp H140A intDevice Call ibconfig intDevice ibcREADDR 1 Main code section Used to return response Terminators Data string sent to instrument Device number used with IEEE Show main window Terminators are lt CR gt lt LF gt Clear return string Initialize the IEEE device Setup Repeat Addressing Do Do Wait loop DoEvents Give up processor to other events Loop Until gSend True Loop until Send button pressed gSend False Set Flag as False strCommand frmIEEE txtCommand Text Get Command strReturn Clear response display strCommand UCase strCommand Set all characters to upper case If strCommand EXIT Then Get out on EXIT End End If Call ibwrt intDevice strCommand amp term Send command to instrument If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If InStr strCommand lt gt 0 Then Ch
37. 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 434 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 the 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
38. and Standard Event Status Enable Register 4 4 4 1 4 IEEE Interface Example Programs eere rien eee etin 4 5 Lake Shore Model 450 Gaussmeter User s Manual TABLE OF CONTENTS Continued Chapter Paragraph Title Page 4 1 4 1 IEEE 488 Interface Board Installation for Visual Basic Program eeeeeeeese 4 5 4 1 4 2 Visual Basic IEEE 488 Interface Program Getup 4 7 4 1 4 3 IEEE 488 Interface Board Installation for Quick Basic Program 4 10 4 1 4 4 Quick Basic Program zie nee te ct eio e ep ee tie atin eR DE at 4 10 4 1 4 5 Program Operation nier DRE EHE REC AEA 4 13 4 1 5 Troubleshooting oe eed rec De pe T D Pe eec E Ls es p e ERO oe Dee eet 4 13 4 2 SERIAL INTERFACE OVERVIEW A 4 14 4 2 1 Physical Gonnet Missoni tcr oce ro tet ph cbe E ethane Lr ces Do Rate dece nn oaa 4 14 4 2 2 Hardware SUpPO Mies D dE Eege egene ed EE e de dE gute 4 15 4 2 3 Character Formal EE 4 15 4 2 4 E El EE 4 15 4 2 5 Message Flow Control Liane Liter er Lea pe dni Bee Dee veo dde 4 16 4 2 6 Ghanging Baud Rate ide c era eee ep iculrie d ed 4 16 4 2 7 Serial Interface Example Progorams A 4 17 4 2 7 1 Visual Basic Serial Interface Program Setup ssseseeseesieesreeiteiretttstttttnnetnntinntnnttnnstnnenstennne 4 17 4 2 7 2 Quick Basic Serial Interface Program Setup sssssseeeeeeeenene 4 20 4 2 7 3 Program Operation asie enema e cetera ia eec e ede eso Tete iv ode v eee iden 4 21
39. and return to the normal display If the 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 the 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
40. 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 O 2 Because the Model 450 input impedance is 420 Q there is a voltage drop due to lead resistance in series with the gaussmeter input The Lake Shore Hall generator sensitivity given on the data sheet 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 5 0 and 15 mV kG HSE at its input Reable Rcust e oe pen Circui Sensitivity Gaussmeter Input Rcable Poust Sensitivity at Gaussmeter input is Ee Reable Lake Shore Model Reust Customer reduced by the lead input voltage divider 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
41. 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 W 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 4 Alarm Alarm Off On Alarm On 4 Alarm Alarm Off On 3 kG 2 kG 1 kG 0 kG 1 kG 2 kG 3 kG Example of operation E Low zem with alarm triggered by readings OUTSIDE Point 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 The
42. 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 Accuracy 0 5 Field Strength 30G 91A 25G I1A 12G I1A 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 3 Q 6 3 mH 10 Q 36 mH 20 Q 93 mH 2 A DC or AC RMS 10 to 40 C 50 to 104 F Coil Resistance Inductance Maximum Continuous Current Operating Temperature Range 1 25 WIDE 1 00 HIGH OPENING THRU BOTH SIDES BANANA JACKS CURRENT INPUT P 450 5 08 bmp Figure 5 8 Model MH 2 5 Helmholtz Coil 5 8 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual
43. 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 not 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 zero 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 electr
44. 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 model 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 Ra
45. 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 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 a command 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 25 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 TE
46. in diameter opening 57 2 mm 2 3 in 31 8 mm 1 3 in 524mm 4 mm 2 1 in p 304 8 mm 12 in gt Depth of Opening 279 4 mm 11 in gt Side View 4065_Chamber eps Figure 5 13 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 C 450 5 14 eps Figure 5 14 Model 4001 RJ 11 Cable Assembly 000000000000010 25000000000000 gae s you zz uuu gg Se A3 mm 1 7 inches 0 6 inches C 450 5 15 eps Figure 5 15 Model 4002 RJ 11 to DB 25 Adapter 000001 90000 O 0 6 inches C 450 5 16 eps Figure 5 16 Model 4003 RJ 11 to DE 9 Adapter 5 12 Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual Refer to NOTE Customer must use 5 64 2 mm hex key to remove four existing ee screws from sides of instrument Unit on right side mounting shown Unit on left side also possible N X Bw Item Description P N Qty PS Ke 1 Rack Mount Ear 107 440 1 Ng 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 1 2 Inch 0 035 4 FHMS Phillips 6 Screw 8 32 x 3 8 Inch 0 081 6 FHMS Phillips C 450 5 17 eps Figure 5 17 Model RM 1 2 Rack Mount Kit Accessories and Probes 5 13 Lake Shore Model 450 Gaussmeter User s Manual
47. nennen nennen 6 5 6 6 Optional Serial Interface Cable and Adapters 6 6 6 7 Operating Software EPROM Deplacement 6 7 APPENDIX A GLOSSARY OF TERMINOLOGY eeeeeeeeeeeeee nennen nnn nnne nnn tnn nn nnn natnm sinn n ns tnn nantes nennt A 1 APPENDIX B UNITS FOR MAGNETIC PROPERTIES ccsssccsseeeseeeesseeeeseeenseeeneeeenseeeaeeaeaseeeaseasaseeeaseaeaseeeasaeseeaees B 1 APPENDIX C HALL GENERATOR S eege C 1 C1 0 EE C 1 C2 0 Theory OF Operatia eegen fen ees rees Hades egene een eege WE Gier C 1 C3 0 Hall Generator Generic Hookup eene nnne nnne nennen nennen nennen nnns nes C 3 C4 0 Using a Hall Generator with the Model Ap C 4 C5 0 Specifications s PAT oR ERU UE IER C 5 C6 0 HALEGAL EXE Program wits pesieveins aote tir re cepe eee y ve Gent a i steed ae nee C 8 Qooodoommym AAAA 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 daaa AA KAU OO cl OO E Oh A ROM DARWON WNH A anno ooo Ci CIO C1 O1 C1 C1 OF C1 C1 C1 OO Joo ob O OO OO OO OO OD OO OO Joo ob OOOOOoO0 cz OO P GO Lake Shore Model 450 Gaussmeter User s Manual LIST OF ILLUSTRATIONS Figure No Title Page Model 450 Gaussmeter Front Panel 1 2 Model 450 Ke ET WEE 2 2 Ball e ue 2 3 Model MCBL XX User Programmable Cable Accessory sssssseseiesrssirssirssirssirrssrrssrrssrnssrnssrns 2 4 Model 450 Front Panel i ucc adiret bn tote ie rra Lag etd ie pea Fa Regna d eta eed Reden a o Aade 3 1 Front Panel Display Definitton
48. of Lake Shore Cryotronics Inc MS DOS and Windows 95 98 NT 2000 are trademarks of Microsoft Corp NI 488 2 is a trademark of National Instruments PC XT AT and PS 2 are trademarks of IBM Copyright 1992 2000 2002 2005 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 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 73 23 EEC 89 336 EEC Standard to which Conformity is declared EN 61010 1 2001 Overvoltage II Pollution Degree 2 EN 61326 A2 2001 Class A Annex B Model NUMBER Sui a cam UO bct 450 d eren Signature Date Ed Maloof Printed Name Vice President of Engineering Position Lake Shore Model 450 Gaussmeter User s Manual Electromagnetic Compatibility EMC for the Model 450 Gaussmeter Electromagnetic Compatibility EMC of electronic equipment is a growing concern worldwide Emissions of and immunity to electromagnetic interference is now part of the design a
49. port at 9600 Baud Use the following procedure to develop the Serial Interface Program in Visual Basic 1 Or to noo Start VB6 Choose Standard EXE and select Open Resize form window to desired size On the Project Menu click Components to bring up a list of additional controls available in VB6 Scroll through the controls and select Microsoft Comm Control 6 0 Select OK In the toolbar at the left of the screen the Comm Control will have appeared as a telephone icon Select the Comm control and add it to the form Add controls to form a Addthree Label controls to the form b Addtwo TextBox controls to the form c Add one CommandButton control to the form d Addone Timer control to the form On the View Menu select Properties Window In the Properties window use the dropdown list to select between the different controls of the current project Label1 Command1 ia Serial Interface Program Label3 Label2 10 Set the properties of the controls as defined in Table 4 5 11 Save the program Remote Operation 4 17 Lake Shore Model 450 Gaussmeter User s Manual Table 4 5 Serial Interface Program Control Properties Current Name Property New Value Label1 Name IbIExitProgram Caption Type exit to end program Label2 Name IbICommand Caption Command Label3 Name lbIResponse Caption Response Texti Name txtCommand Text lt blank gt Text2 Name txtResponse Text lt blank gt
50. see AOCON Set ANOD to 0 for user scaling Paragraph 3 12 1 then use ANOH and ANOL to define maximum and minimum Default Analog Out Query ANOD 0 1 0r2 Refer to ANOD command for description Define Analog Out High Setpoint ANOH XXX XX Nothing Set ANOD to Mode 0 for user scaling Enter sign up to 5 digits and decimal point Place decimal appropriate to range Analog Out High Setpoint Query ANOH IXXX 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 Set ANOD to Mode 0 for user scaling Enter sign 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 Ma
51. 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 gt amp akeShore 450 Gaussmeter AC DC Peak RMS Local Escape 7 felfoll 1 Filter esia Address 4 5 6 l l A ko so Baud l 1 l 2 3
52. 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 The relative feature also interacts with other features wien alarm is EES the alar pormi follow the relative reading When Relative and Max Hold EE 1 om P oD ope 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 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
53. the turns of a coil must be entered to perform flux measurements in units of Volt seconds V s Webers Wb or Maxwells Mx 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 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 Te
54. they must be separated by a semi colon Only one query is permitted per communication but it can be chained to the end of a command The total communication string must not exceed 64 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting The format is command mnemonic gt lt space gt lt parameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 4 3 Terminators must be sent with every message string Remote Operation 4 15 Lake Shore Model 450 Gaussmeter User s Manual Message Sirings Continued 4 2 5 4 2 6 4 16 A query string is issued by the computer and instructs the instrument to send a response The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in Paragraph 4 3 Terminators must be sent with every message string The computer should expect a response very soon after a query is sent A response string is the instruments response or answer to a query string The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parame
55. 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 4 20 Remote Operation 4 2 7 3 Lake Shore Model 450 Gaussmeter User s Manual Program Operation Once either example program is running try the following commands and observe the response of the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND FIELD 000 12 ENTER COMMAND RANGE 0 ENTER COMMAND UNITS G ENTER COMMAND ACDC 0 ENTER COMMAND FILT 0 Field Reading Query Unit returns field reading in the form XXX XX Decimal point placement appropriate to range Range Query Unit returns appropriate range 0 highest range through 3 lowest range Units Query Unit returns appropriate units G gauss T tesla AC or DC Query Unit returns appropriate setting 0 DC 1 AC Filter Query Unit returns appropriate setting 0 Off 1 On ENTER COMMAND FILT 1 FILT Unitturns the filter On then returns a 1 to verify the change 1 ENTER COMMAND The following are additional notes on using either Serial Interface program e If you enter a correctly spelled query without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries an
56. 2 kG 1 MRT XXX 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 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 The probe will exhibit its full accuracy if used without the extension cable MPEC XXX 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 460 probes available Axial Transverse Tangential and Gamma named for the Hall sensor orientation Because the Mo
57. Auto Range DCor AC Field Measurement Individual Linearization of Hall Probes Temperature Compensation of Hall Probes certain models only e Alphanumeric Display 434 digit 1 Part In 30 000 Resolution On All Ranges 5 4 digit with DC and Filter 1 Part In 300 000 Resolution 2Line by 20 Character Vacuum Fluorescent Display Other Major Operating Functions Display Filter Gauss or Tesla Units Max Hold Relative Reading Audible Alarm for High and Low Field Interface EEE 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 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 manual is subject to change without notice Introduction 1 1 1 1 Lake Shore Model 450 Gaussmete
58. EEE 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 4 0 4 1 Lake Shore Model 450 Gaussmeter User s Manual CHAPTER 4 COMPUTER INTERFACE OPERATION GENERAL This chapter provides operational instructions for the computer interface for the Lake Shore Model 450 Gaussmeter Either of the two computer interfaces provided with the Model 450 permit remote operation The first is the IEEE 488 Interface described in Paragraph 4 1 The second is the Serial Interface described in Paragraph 4 2 The two interfaces share a common set of commands detailed in Paragraph 4 3 Only one of the interfaces can be used at a time 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 instruments on the interface bus perform one or more of the interface functions of TALKER LISTENER or BUS CONTROLLER A TA
59. Enter to i 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 Lake Shore Model 450 Gaussmeter User s Manual 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 updating at 5 readings per second the filter settles in 1 6 seconds Exponential Response with Filter Points set to 9 Linear Response with Filter Points set to 8 Step Change in Magnetic Field
60. 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 is raised the instrument is On When O is raised the instrument is Off Power Switch Line Cord Input O Off On Fuse Drawer s LINE 10 5 Voltage 40 VA MAX FUSE DATA 100 120 V 05A 0 25 x 125 in T 220 v 5x20mmT 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 pa
61. G Flexible DC 10 to HST 30kG 0 Cto 0 13 G C 0 005 Tubin 400 Hz 9 75 C MFT 2903 VJ 0 030 gt SE 1 E 0 09 G C 0 015 ped ed Pod e MFT 2903 VH UU approx HST 2 30 o 0 13 G C 0 005 C This table is for L 15 0 5 inches and S 0 75 inch Flexible MFT 4F15 VH 0 040 Tubing HSE 1 po j 0 09 GPC 0 015 0 150 0 150 DC 10 to 0 C to C 40 005 song de SRo oH 40 15 75 C MFT F15 VG 9 9 099 approx Fiber Z HsT 2 015 to 0 13 GPC 0 005 C discs 30 kG Flexible_Transverse eps Figure 5 6 Definition of Lake Shore Flexible Transverse Probes FLEXIBLE AXIAL PROBE r 25 L SS E Cable Length 6 6 feet er dia 0 125 0 020 Active Stem Frequency Corrected Operating Temperature Coefficient max Model No L A e Material Bane Type Accuracy Temperature e WA Le ea i Ld 15 0 025 0 125 0 040 dia Flexible DC 10 to 0 25 to 0 C to g MFA 1815 VH 0 005 approx 400 Hz HSE 1 30 kG 75 C 0 09 G C 0 015 C Flexible_Axial eps Figure 5 7 Definition of Lake Shore Flexible Axial Probe Accessories and Probes 5 7 Lake Shore Model 450 Gaussmeter User s Manual 5 4 HELMHOLTZ COIL LOW FIELD STANDARDS Lake Shore offers three Helmholtz coils 2 5 6 and 12 inch diameter Check the latest Lake Shore brochures or our website for any recent additions to this line These coils
62. Gamma Y r Lambda A A Tau T T Delta A Mu u M Upsilon v Y Epsilon E Nu v N Phi d o Zeta 6 Z Xi e Chi X X Eta n H Omicron o O Psi y KN Theta 0 Pi T II Omega m 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 p
63. HR 10 Terminators are lt CR gt lt LF gt INS SPACES 2000 Clear for return string LINE INPUT ENTER COMMAND or EXIT CMD Get command from keyboard CMD UCASES CNDS Change input to upper case IF CMD EXIT THEN END Get out on Exit CMD CMD TERMS CALL IBWRT DEV12 CMD Send command to instrument CALL IBRD DEV12 INS Get data back each time ENDTEST INSTR INS CHR 13 Test for returned string IF ENDTEST 0 THEN String is present if CR is seen INS MIDS INS 1 ENDTEST 1 Strip off terminators PRINT RESPONSE INS Print return string ELSE PRINT NO RESPONSE No string present if timeout END IF GOTO LOOP2 Get next command 4 12 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 1 4 5 Program Operation Once either example program is running try the following commands and observe the response of the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND IDN Identification query Instrument will return a string identifying itself RESPONSE LSCI MODEL450 0 020303 term ENTER COMMAND FIELD Field reading query Instrument will return a string with the present field reading RESPONSE 12 345 term ENTER COMMAND FIELDM Field multiplier query Instrument will return a string with the field units multiplier Blank indic
64. Hall generators Figures C 8 thru C 10 with specifications Table C 3 10 in min Ge 0 20 in i diameter E gt LES 2a O B gt gt gt 0 105 M LL 0 20 in diameter C 421 C 5 eps Figure C 5 Axial Hall Generator HGA 3010 HGA 3030 and HGCA 3020 Dimensions 0 63 in gt 10 in min 0 180 in Lead Length 0 240 in PD Ka Pad xX XK max e XXNX SCH B d Center of a ae Protective Active Area 0 043 in max Ceramic Case C 421 C 6 eps 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 Ic 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 2 0 RDG 150 to 150 kG 2 0 RDG 150 to 150 kG Zero field offset voltage Ic nominal 200 uV max 200 uV max control current Operating temperature range 4 2Kto 375K 4 2 Kto 375K Mean temperature coefficient of magnetic 0 01 K approx 0 01 K approx sensitivity Mean temperature coefficient of offset Ic 0 4 p V K max 0 4 uV K max nominal control current Mean temperature coefficient of resistance 0 6 K max 0 6 K max 34 AWG copper w Teflon insulation 34 AWG copper w Teflon insulation Hall Generator C 5
65. IVE 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 equal 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 F e v x B force on electron VH VH Blue Clear or Yellow High Mobility I V 5 Semiconductor a Indium arsenide b Gallium arsenide 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 e CAA C AZ D Transverse C4 B lt lt T x Axial C 421 C
66. Initial Susceptibility and Differential Susceptibility As in the case of magnetization the susceptibility is often Seen expressed 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
67. L XX 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 BNOs 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 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 4596 1096 AC input voltage 2 Check fuse drawer window for proper voltage setting If incorr
68. LKER 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 Model 450 performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is the digital computer which tells the Model 450 which functions to perform Below are Model 450 IEEE 488 interface capabilities SH1 Source handshake capability RL1 Complete remote local capability DC1 Full device clear capability DTO No device trigger capability 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 SR1 Service request capability AH1 Acceptor handshake capability e PPO No parallel poll capability Et Open collector electronics NOTE The Model 450 IEEE 488 Interface requires that repeat addressing be enabled on the bus controller Instruments are connected to the IEEE 488 bus by a 24 conductor connector cable as specified by the standard Refer to Paragraph 6 5 1 Cables can be purchased from Lake Shore or other electronic suppliers Cable lengths are limited to 2 meters for each device and 20 meters for the entire bus The Model 450 can drive a bus with up to 10 loads If more instruments or cable length is required a bus expander must be used
69. Memory EPROM Integrated Circuit IC The EPROM is numbered U36 and located just behind the microprocessor IC U31 The EPROM also has a label on top identifying the software version and date see Figure 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 n e e 3i LES Operating Software Transformer Power Inlet On TOUS ou poule
70. Model 4065 Large Zero Gauss Chamber 5 11 Model 4001 RJ 11 Cable Assembly sse enne 5 12 Model 4002 RJ 11 to DB 25 Adatter eene nnne nnns 5 12 Model 4003 RJ 11 to DE 9 Adapter esent nennen 5 12 Model RM 1 2 Rack Mount kt 5 13 Model RM 2 Dual Rack Mount Ghet nennen ener nnn 5 14 Power Fuse ee 6 3 DA 15 PROBE INPUT Connector Details 6 4 Corrected and Monitor ANALOG OUTPUTS Connector Details ssessseesse 6 4 SERIAL I O RJ 11 Connector Details sss eene 6 4 IEEE 488 Connector Detalls 5 5 r rrr etia nsa ct rto eh n nea Ra e eh ka eT da ee RR Fe EIER EVARA 6 5 Model 4001 RJ 11 Cable Assembly Wiring Details sese 6 6 Model 4002 RJ 11 to DB 25 Adapter Wiring Details 6 6 Model 4003 RJ 11 to DE 9 Adapter Wiring Details sen mm 6 6 Location Of Operating Software EPROM nennen nnne nennen senten nennen nas 6 7 Hall Generator Theory cei dade it o te ia atenta teats nates C 2 Axial and Transverse Configurations nennen nennen nennen nnns C 2 Typical Hall Generator Hookup ssssssssssssseeeseeene enne entente nennen nensi nnns inner nnns C 4 Hall Generator Input Impedance sss esee enne ener enne nnn snnt nenas C 4 Axial Hall Generator HGA 3010 HGA 3030 amp HGCA 3010 Dimensions e C 5 Transverse Hall Generator HGT 3010 HGT 3030 amp HGCT 3020 Dimensions C 5 Axial Hall Generator HGA 2010 D
71. Off 3 kG 2 kG 1 kG 0 kG 1kG 2kG 3kG Example of operation Low Alarm with alarm triggered by readings INSIDE user Point 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 St ete Pe EUER 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 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
72. Query mnemonics and parameter data if necessary is described in Paragraph 4 3 Terminators must be sent with every message string Issuing a query does not initiate a response from the instrument A response string is sent by the instrument only when it is addressed as a talker and the computer becomes the listener The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in Paragraph 4 3 Remote Operation 4 3 Lake Shore Model 450 Gaussmeter User s Manual 4 1 3 Status Registers 4 1 3 1 There are two status registers the Status Byte Register described in Paragraph 4 1 3 1 and the Standard Event Status Register in Paragraph 4 1 3 2 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 E ee a EE es a E EH Weigh ng 128 64 32 16 8 4 2 1 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 Status Byte Register Inhibit or enable these reports by turning their corresponding bits off or on in the Service Request Enable Register The xSRE command sets the bit
73. R RARE ihe 2 1 2 2 Repackaging For Shipment eristuse ie e eerie Dep aree erg epe aee eoe dee vd 2 1 2 3 Definition of Rear Panel Connechlons enne 2 2 2 4 Line Input Assermbly 2 eet cette ente tee rp ederet rere cec e SEN cd ge bees Ed 2 3 2 5 lee ele Ile 2 3 2 5 1 Attachment to a Hall Generator 2 4 2 6 Corrected and Monitor Analog Outputs nennen nnne rennen nnne 2 4 2 7 Initial Setup and System Checkout Procedure nennen 2 4 Be OPERAT ON EE 3 1 3 0 EIC EE 3 1 3 1 Definition of Front Panel Controls AAA 3 1 3 1 1 Front Panel Keypad Deimtons AA 3 1 3 1 2 Front Papel Display ne eei ds east ee reve ade OE ened ates 3 3 3 2 Max Hold and Max EE 3 3 3 3 Zero Mee TEE 3 3 3 4 Select Range and Auto Range eene enne nnne nen en nnne enn entrent enne nnne 3 4 3 5 AG DG and Peak RMS ue steen rk T rper cta re ue Pa a Cr de ate Zeien EE ERE Cr RR deepens 3 5 3 6 BI i eite ia i mai ud mete edet 3 5 3 6 1 Display IEEE 3 5 3 6 2 Field and Temperature Compensation essen 3 6 3 7 Gauss Tesla EE 3 6 3 8 Relative Set and Relative OniCnt AAA 3 7 3 9 Alarm Set and Alarm OnVOff rtis ri order eset rete atento nta Settee fa map cipe eoe s 3 7 3 10 l ocal and Address ite piti Oe HE a e DU thas DR GI ERR GI Dig 3 9 3 11 Baud EE 3 9 3 12 Analog Out nne E e Rete ieee DE EL den bus 3 9 3 12 1 Gorrected Analog Out fie 12 me trees ite iie eder i eerie o reca re eda ee aes beer 3 10 3 12 2 Monitor Analog Ke LEE 3 11 3 12 3 Analog O
74. RM 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 LFEO 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 CR LF 1 Line feed and carriage return LF CR 2 Line feed LF 3 No terminating characters 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 26 Set AC or DC Magnetic Field Reading Status ACDC Ooracpc 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
75. Tesla Resolution Resolution Range AC or DC Range AC or DC e EN w Filter on DC Filter On EN w Filter ort DC Filter On 430 kG 43 kG 300 G 30 G Ultra High Sensitivity Probe UHS Oooo o oo o o Gauss OOO U Tesla Resolution Resolution Range AC or DC Range AC or DC 0 01 mG 0 001 mG 0 001 uT 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 W 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 Enter 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
76. 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 approx Output resistance approx Nominal control current 100 mA 100 mA 100 mA Ion current non heat sinked Magnetic sensitivity SCH 7 5 to 12 5 mV kG 0 55 to 1 05 mV kG 6 0 to 10 0 mV kG Maximum 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 lc 100 uV max uV max 75 uV max nominal control current Operating temperature 40 to 100 C 40 to 100 C 40 to 100 C range Mean temperature 0 08 C max 0 005 C max 0 04 C max coefficient of magnetic sensitivity Mean temperature 1 uV C max 0 4 uV C max 10 3 uV C coefficient of offset Ic 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 Gaussmet
77. aces 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 0O0rFILT 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 Refer 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 Displa
78. ached the following message is displayed 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 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 separat
79. ag 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 ESE bit weighting 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 ESR bit weighting Format nnn term Queries for various Model 450 error conditions and status The integer returned represents the sum of the bit weighting of the event flag bits in the Standard Event Status Register Query Identification IDN manufacturer model numbers serial numbers 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 comm
80. and string Not the same as OPC 4 23 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 weighting 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
81. ated gauss k indicates kilo gauss etc RESPONSE k term ENTER COMMAND RANGE 0 Range command Instrument will change the field range to the highest setting No response will be sent ENTER COMMAND RANGE Range query Instrument will return a string with the present range setting RESPONSE O term The following are additional notes on using either IEEE 488 Interface program e If you enter a correctly spelled query without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries and should have a space separating the command and associated parameters Leading zeros and zeros following a decimal point are not needed in a command string but are sent in response to a query A leading is not required but a leading is required 4 1 5 Troubleshooting New Installation 1 Check instrument address 2 Always send terminators 3 Send entire message string at one time including terminators 4 Sendonly one simple command at a time until communication is established 5 Be sure to spell commands correctly and use proper syntax 6 Attempt both Talk and Listen functions If one works but not the other the hardware connection is working so look at syntax terminators and command format If only one message is received after resetting the interface check the repeat addressing setting It should be enabled Old Installation No Longer Working 1 P
82. ation that can be transmitted by the interface Each character is 10 bits long and contains data bits bits for character timing and an error detection bit The instrument uses 7 bits for data in the ASCII format One start bit and one stop bit are necessary to synchronize consecutive characters Parity is a method of error detection One parity bit configured for odd parity is included in each character ASCII letter and number characters are used most often as character data Punctuation characters are used as delimiters to separate different commands or pieces of data Two special ASCII characters carriage return CR ODH and line feed LF OAH are used to indicate the end of a message string Table 4 4 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 4 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command strings can be chained together in one communication but
83. b com 7 Connect the instrument to the interface board and power up the instrument Verify the address is 12 and terminators are CR LF Quick Basic Program The IEEE 488 interface program in Table 4 3 works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible running DOS or in a DOS window It assumes your IEEE 488 GPIB card is installed and operating correctly refer to Paragraph 4 1 4 3 Use the following procedure to develop the Serial Interface Program in Quick Basic 1 Copy c gpib pc Qbasic qbib obj to the QuickBasic directory QB4 2 Change to the QuickBasic directory and type link q qbib obj bqlb4x 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 I qbib glb 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 Enter the program exactly as presented in Table 4 3 Name the file ieeeexam bas and save 5 Run the program 6 Type acommand query as described in Paragraph 4 1 4 5 7 Type EXIT to quit the program Remote Operation Lake Shore Model 450 Gaussmeter User s Manual National Instruments GPIBO Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address Select the primary GPIB address by Secondary GPIB Address using the le
84. ces 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 Donot 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 OO AEN OD Oc cerco DO SIE 9 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 O Remove the instrument power cord With a small screwdriver release the drawer holding the line voltage selector and fuse Slide out the removable plastic fuse holder from the drawer Rotate the fuse holder
85. ches and relay contacts Provides an open circuit when actuator is in the free unenergized position oersted Oe The cgs unit for the magnetic field strength H 1 oersted 105 4n 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 its ends pascal Pa The SI unit of pressure equal to 1 N m Equal to 1 45x104 psi 1 0197x10 kgr cm 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 xi where ais the 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 unde
86. chnical Terms Third Edition New York McGraw Hill 1969 IBSN 0 395 20360 0 2 Christopher J Booth Editor The New IEEE Standard 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 Lake Shore Model 450 Gaussmeter User s Manual APPENDIX B UNITS FOR MAGNETIC PROPERTIES Table B 1 Conversion from CGS to SI Units 5 Gaussian Conversion SI amp Quantity Symbol amp CGS emi Factor CH Rationalized mks Magnetic flux density Magnetic induction 4 o Magnetic Flux Magnetic potential difference gilbert Gb 10 47 ampere A magnetomotive force Magnetic field strength magnetizing force O oersted Oe Gb cm 10 4n Am Volume magnetization MI emu cem Al E NI U L 10 1 Volume magnetization T 107 47 Al J emu g A m kg 4n x 10 Wb m kg X 3 3 Mass magnetization Magnetic polarization intensity of magnetization 3 Asm joule per Magnetic moment emu erg G eae UT Magnetic dipole moment Vom VUN dimensionless Henry per meter Volume susceptibility euer Wal x 107 H m Wb A m n 3 An x 10 m kg Mass susceptibility cm g emu g 4n 2 x 107
87. ctor 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 the cable secure and prevents interference Refer to Paragraph 3 15 for additional probe considerations Installation Lake Shore Model 450 Gaussmeter User s Manual 2 4 2 4 1 2 4 2 2 4 3 2 5 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
88. d Probes Lake Shore Model 450 Gaussmeter User s Manual TRANSVERSE PROBES Cable length 6 6 feet 0 36 0 030 dia Active Stem Fre Corrected Temperature Model No Area Material Se Type Accuracy bud Coefficient Max 9 of rdg Range Calibration MMT 6J02 VH 2 0 125 6J04 VH 4 30 125 MNT 6J04 VH 4 0125 o ces 9 489 Dc MMT 608 VH 8 50 125 max 20 005 HSE 1 MMT 6J18 VH 18 0 25 MNT 4E02 VH 2 50 125 0 045 0 x ie 0 150 0 040 MNT 4E04 VH 4 amp 0 125 max S din 400 Hz MMT 6J02 VG 2 0 125 0 050 approx MMT 6J04 VG 4 0 125 0 MMT 6J08 VG 8 0 125 MMT 6J18 VG 18 0 125 0 125 MNT 4E02 VG 2 0 125 9 045 MNT 4E04 VG 4 0 125 ax 10 to 0 25 dia 0 210 Stainless 400 Hz 42 to 1 5Kto 0 010 61 1 HST 1 UU ici EES 0 010 10 050 Steel 100kG 350K per C Transverse eps Figure 5 3 Definition of Lake Shore Transverse Probes TANGENTIAL PROBE m 2 5 f L ER S D RC NN GS F he Area 1 Cable length 6 6 feet 0 36 0 030 dia del Acti St F Corrected Temperature c A pn See Deg Type Accuracy Pur Coefficient Max 9 of rdg Range Calibration unm 1 5 0 125 0 38 0 030 0 020 dia DC 10 to 0 25 0 Cto Plastic 1 HSE 1 0 1 G C 0 05 C Tangential eps Figure 5 4 Definition of Lake Shore Tangential Probe Accessories and Probes 5 5 Lake Shore Model 450 Gau
89. d should have a space separating the command and associated parameters Leading zeros and zeros following a decimal point are not needed in a command string but they will be sent in response to a query A leading is not required but a leading is required 4 2 8 Troubleshooting New Installation 1 Check instrument Baud rate 2 3 Always send terminators 4 do not 5 6 Make sure transmit TD signal line from the instrument is routed to receive RD on the computer and vice versa Use a null modem adapter if not Send entire message string at one time including terminators Many terminal emulation programs Send only one simple command at a time until communication is established Be sure to spell commands correctly and use proper syntax Old Installation No Longer Working Power instrument off then on again to see if it is a soft failure 2 Power computer off then on again to see if communication port is locked up 3 Verify that Baud rate has not been changed on the instrument during a memory reset 1 4 Check all cable connections Intermittent Lockups Check cable connections and length Increase delay between commands to 100 ms to make sure instrument is not being over loaded 1 2 4 21 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 3 IEEE 488 SERIAL INTERFACE COMMAND SUMMARY There are four command groups Common Commands in Paragraph 4 3 2 Interface
90. del 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 4 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 as a Model MFT 3E03 or MNA 1904 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 A superior choice for AC measurements would b the Model MNT 4E04 type fiberglass epoxy stem probes Several stem lengths are offered for
91. diation 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 0 596 Neutron cumulative radiation 20 1 MeV 10 5 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 8 Probe Specifications Terminology used in Figures 5 1 thru 5 7 are defined as follows Definition of Probe Terminology Usable Full Scale Ranges Vs Probe Type A Distance from tip to center line of active area Type HST 1 HST 2 HSE 1 UHS 1 B Magnetic flux density vector for reading 300G 300G 30G 300mG HST High Stability Probe Usable zk 3kG 300G 3G HSE High Sensitivity Probe BEE 30kG 30kq 8kG 30G UHS Ultra High Sensitivity Probe 300 kG 30 kG EH GAMMA PROBE gt BS e n L Small variations in or low values of large volume magnetic fields such as that CH 1 T Ba of the Earth or fringe fields around large solenoids can be measured with Ke
92. e 5 16 4004 IEEE 488 Interface Cable Connects Model 450 to customer supplied computer with IEEE 488 Interface Cable is 1 meter 3 3 feet long See Figure 6 5 Half Rack Mounting Kit for One 1 2 Rack Gaussmeter Half length mounting panel and RM 1 2 mounting ears to attach one Model 450 Gaussmeter to a 483 mm 19 inch rack mount space See Figure 5 17 Dual Mounting Shelf for Two 1 2 Rack Gaussmeters Mounting panel and mounting RM 2 ears to attach two Model 450 Gaussmeters to a 483 mm 19 inch rack mount space See Figure 5 18 4060 Standard Zero Gauss Chamber For standard probe calibration Size 32 x 32 x 61 mm 1 3 x 1 3 x 2 4 in Bore 12 mm dia x 51 mm deep 0 5 x 2 in See Figure 5 12 4065 Large Zero Gauss Chamber For Gamma Probe calibration Size 57 x 53 x 305 mm 2 3 x 2 x 12 in Bore 19 mm dia x 279 mm deep 0 75 x 11 in See Figure 5 13 MAN 450 Model 450 Gaussmeter User s Manual Hall Generator Cable Assembly The MCBL Cable Assembly connects a discrete Hall generator to the Model 450 Gaussmeter See Paragraph 2 5 1 The cable ships with the HALLCAL EXE program which permits cable PROM programming through a PC or MCBL XX compatible computer serial port Because of the many calibration intricacies the user is responsible for measurement accuracy Refer to Appendix C MCBL 6 Hall Generator Cable Assembly 2 meters 6 feet long MCBL 20 Hall Generator Cable Assembly 6 mete
93. e 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 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 l
94. e controls as defined in Table 4 1 11 Save the program Remote Operation 4 7 Lake Shore Model 450 Gaussmeter User s Manual Table 4 1 IEEE 488 Interface Program Control Properties Current Name Property New Value Label1 Name IbIExitProgram Caption Type exit to end program Label2 Name IbICommand Caption Command Label3 Name IblResponse Caption Response Texti Name txtCommand Text lt blank gt Text2 Name txtResponse Text lt blank gt Command1 Name cmdSend Caption Send Default True Form1 Name frml EEE Caption IEEE Interface Program 12 Add code provided in Table 4 2 a Inthe Code Editor window under the Object dropdown list select General Add the statement Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend Click as shown in Table 4 2 c In the Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form Load Add the code to this subroutine as shown in Table 4 2 13 Save the program 14 Run the program The program should resemble the following i IEEE Interface Program iof E Type exit to end program Command Response 15 Type in a command or query in the Command box as described in Paragraph 4 1 4 5 16 Press Enter or select the Send button with the mouse to send command 17
95. e magnetic reference values ranging from 100 G to 20 kG but the most widely used value is 1 kG Reference magnet accuracy is typically 0 596 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 magnet The calibration point is the largest reading in the midpoint area Its amplitude will be approximately twice that of the readings that occur where the probe enters or leaves the magnet 4 7 cm dia 61 845
96. eck to see if query strReturn Space 100 Build empty return buffer Call ibrd intDevice strReturn Read back response If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If strReturn lt gt Then Check if empty string strReturn RTrim strReturn Remove extra spaces and Terminators Do While Right strReturn 1 Chr 10 Or Right strReturn 1 Chr 13 strReturn Left strReturn Len strReturn 1 Loop Else strReturn No Response Send No Response End If frmIEEE txtResponse Text strReturn Put response in text on main form End If Loop End Sub Remote Operation 4 9 4 1 4 3 4 1 4 4 4 10 Lake Shore Model 450 Gaussmeter User s Manual IEEE 488 Interface Board Installation for Quick Basic Program This procedure works on an IBM PC or compatible running DOS or in a DOS window This example uses the National Instruments GPIB PCII IIA card 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 Qu dps Uer uno toe Run IBTEST to test software configuration Do not install the instrument before running IBTEST 6 Run IBCOMF to configure the GPIB PCII IIA board and dev 12 Set the EOS byte to OAH and Enable Repeat Addressing to Yes See Figure 4 3 IBCONF modifies gpi
97. ect 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 Plugin 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 probe cable To place the probe in the zero gauss chamber slide the protective sleeve back exposing the probe tip before placing the tip in the chamber 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 th
98. efined scaling can improve resolution over a selected area For example below is a symmetrical scaling similar to the default scale i 0kG ecd 1 5 kG 1kG 0 5 kG 40 5 kG 1 KG 41 5 kG Output T Voltage 3V 2v 1V Ge 41V 42V 43 To enter this scale press Analog Out Press the Analog Out A or V key to cycle the arrow 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 41 5 kG d 0 KG 40 5 kG 41 KG 2 KG 42 5 KG 43 kG vanes 8v 2V AN HV 42V 48V OV To enter this scale press Analog Out Press the Analog Out A or V key to cycle the arrow 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 number 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 m
99. electronics Hall Generator C 3 Lake Shore Model 450 Gaussmeter User s Manual C4 0 CA lc Hall Generator Model 120CS WW 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 long 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 O 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
100. ely 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 N ie BI akeShore 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 measured 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 E L EE 2 Transverse P
101. emory 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 purchasing 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 dep
102. ends 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 450 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
103. er 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 This program is provided with the purchase of a Model MCBL 6 or 20 Cable Assembly 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 or 20 Cable Assembly IBM or compatible CPU Hall generator meeting the sensitivity ranges given below Calibration or sensitivity constant and serial number of the Hall generator Operation 1 C 8 Set the 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 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 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 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 w
104. es so the above limitation may not apply to you LIMITED WARRANTY STATEMENT Continued 9 EXCEPT TO THE EXTENT ALLOWED BY APPLICABLE LAW THE TERMS OF THIS LIMITED WARRANTY STATEMENT DO NOT EXCLUDE RESTRICT OR MODIFY AND ARE IN ADDITION TO THE MANDATORY STATUTORY RIGHTS APPLICABLE TO THE SALE OF THE PRODUCT TO YOU CERTIFICATION Lake Shore certifies that this product 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 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 firmware can pay for loss of time inconvenience loss 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 o
105. f our product implies that 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 TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distinguish their products as trademarks Where those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or symbol CalCurve Carbon Glass Cernox Duo Twist Quad Lead Quad Twist Rox SoftCal and Thermox are trademarks
106. fan Boltzman Constant c 1 60 k n c 5 6703 x 10 W m K First Radiation Constant 3 7418 x 106 W m Second Radiation Constant 0 0144 mK Gravitation Constant 6 6720 x 10 Nm 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 Gaussmeter 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 C2S001 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 densi
107. ft and right arrow keys Timeout setting This address is used to compute the Terminate Read on EOS talk and listen addresses which Set EOI with EOS on Writes identify the board or device on the Type of compare on EOS i GPIB Valid primary addresses range from 0 to 30 00H to 1EH Send EOI at end of Write Adding 32 to the primary address System Controller forms the Listen Address LA Assert REN when SC Adding 64 to the primary address Enable Auto Serial Polling forms the Talk Address TA Enable CIC Protocol EXAMPLE Selecting a primary address Parallel Poll Duration of 10 yields the following Use this GPIB board EH 10 32 42 Listen address v 10 64 74 Talk address Base I O Address Fl 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 Select the primary GPIB address by Secondary GPIB Address using the left and right arrow keys Timeout setting Serial Poll Timeout This address is used to compute the talk and listen addresses which Terminate Read on EOS identify the board or device on the Set EOI with EOS on Writes GPIB Valid primary addresses range Type of compare on EOS i from 0 to 30 00H to 1EH Send EOI at end of Write Adding 32 to the primary address forms the Listen Address LA Enable Repeat Addressing Adding 64 to the primary address forms the Talk Address TA
108. gister and Standard Event Status Enable Register 4 4 The Standard Event Status Register supplies various conditions of the Model 450 STANDARD EVENT STATUS REGISTER FORMAT Biete qpoer itcm ER Wo Weighing 128 64 32 16 8 4 2 1 Bit Name Bits 1 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 at GE with the sum of the bit weighting for each bit to be set Refer to the xESE command Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Standard Event Status Register and Standard Event Status Enable Register Continued 4 1 4 1 The Standard Event Status Enable Query ESE reads the Standard Event Status Enable Register xESR reads the Standard Event Status Register Once this register is read the bits reset to zero 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 unable to interpret a command due to syntax error unrec
109. he 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 ranges for each probe sensitivity along with fixed display resolution High Stability Probe HST Le Gaus O Tesla Range AC or DC 3 Range AC or DC 3 wi Filter off DC Filter On wi Filter off DC Filter On 0 01 G High Sensitivity Probe HSE Oooo o oo o o Gauss OOO
110. he 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 controls 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 t
111. ia 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 6438 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 10 newton per meter of length This is one of the base units of the SI ampere turn A MKS unit of magnetomotive force equal to the magnetomotive force around a path linking one turn of a conducting loop carrying a current of one ampere or 1 26 gilberts ampere meter A m The SI unit for magnetic field strength H 1 ampere meter 41 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 inst
112. iation from Perpendicular 8 Effect of angular variations on percentage of reading error where Error 1 cos 8 100 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 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 I
113. ick Routine to handle Send button press gSend True Set Flag to True End Sub Private Sub Form Load Main code section Dim strReturn As String Used to return response Dim strHold As String Temporary character space Dim Dim Dim Term As String ZeroCount As Integer strCommand As String frmSerial Show Term Chr 13 amp Chr 10 ZeroCount 0 strReturn strHold vn If frmSerial MSComml PortOpen frmSerial MSComml PortOpen End If frmSerial MSComm1 CommPort frmSerial MSComml Settings 1 True Then False 9600 0 7 1 frmSerial MSComml InputLen 1 frmSerial MSComml PortOpen True Do Do DoEvents Loop Until gSend True gSend False strCommand frmSerial txtCommand Text strReturn strCommand UCase strCommand If strCommand EXIT Then End End If frmSerial MSComml Output If InStr strCommand strCommand amp Term lt gt 0 Then While ZeroCount lt 20 And strHold lt gt Chr 10 If frmSerial MSComml InBufferCount frmSerial Timerl Enabled 0 Then True Terminators Counter used for Timing out Data string sent to instrument Show main window Terminators are lt CR gt lt LF gt Initialize counter Clear return string Clear holding string Close serial port to change settings Example of Comm 1 Example of 9600 Baud Parity Data Stop Read one character at a time Open port Wait loop Give up processor to other events Loop un
114. ier concentration increases with increasing temperature over some temperature range Note Certain semiconductors possess two types 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 ata 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 4r to yield the SI susceptibility See also
115. imensions eese enne C 6 Table No 4 1 Lake Shore Model 450 Gaussmeter User s Manual LIST OF TABLES Title Page IEEE 488 Interface Program Control Properties sssssssssssseeeeeneen nennen 4 8 Visual Basic IEEE 488 Interface Program ccccceeeeeeeeeeeeeeeeeeeeeceeeeecaeeeeaaeeeeaeeseeeesaeeesaaeeeenees 4 9 Quick Basic IEEE 488 Interface Program 4 12 Serial Interface Specifications sess eene enne nnne 4 15 Serial Interface Program Control Properties nennen 4 18 Visual Basic Serial Interface Program 4 19 Quick Basic Serial Interface Program eee 4 20 Conversion from CGS to SI Units ssssssssssssssesseseeeee eene nentes nnne nnns B 1 Recommended SI Values for Physical Constants sse B 2 Cryogenic Hall Generator Specifications ssssssssssssseseseeeeneen enne C 5 Axial Hall Generator Specifications sesssssssssssssee esee nennen nenne C 6 Transverse Hall Generator Gpechhicaitons nennen 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 for the laboratory It features Field Measurement High Accuracy with High Resolution
116. in communication Changing Baud Rate To use the Serial Interface you must first set the Baud rate Press Interface key to display the following screen Select With AT Baud 3 412 36 Press the A or V key to cycle through the choices of 300 1200 or 9600 Baud Press the Enter key to accept the new number Remote Operation Lake Shore Model 450 Gaussmeter User s Manual 4 2 7 Serial Interface Example Programs Two BASIC programs are included to illustrate the serial communication functions of the instrument The first program was written in Visual Basic Refer to Paragraph 4 2 7 1 for instructions on how to setup the program The Visual Basic code is provided in Table 4 6 The second program was written in Quick Basic Refer to Paragraph 4 2 7 2 for instructions on how to setup the program The Quick Basic code is provided in Table 4 7 Finally a description of operation common to both programs is provided in Paragraph 4 2 7 3 While the hardware and software required to produce and implement these programs not included with the instrument the concepts illustrated apply to almost any application where these tools are available 4 2 7 1 Visual Basic Serial Interface Program Setup The serial interface program works with Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better with a serial interface It uses the COM1 communications
117. ine 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 4 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 Paragraph 3 2 Zero Probe Zeros or nulls effects of ambient low level fields from the probe To use place tip of probe into Zero Gauss Chamber press Zero Probe then Enter Refer to Paragraph 3 3 Select Range Manually selects field measurement range Available ranges depend on which p
118. ing 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 3 15 2 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 restored 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 att
119. iod and the Product is shipped freight prepaid Lake Shore will at its option either repair or replace the Product if it is so defective without charge to the owner for parts service labor or associated customary return shipping cost Any such replacement for the Product may be either new or equivalent in performance to new Replacement or repaired parts will be warranted for only the unexpired portion of the original warranty or 90 days whichever is greater 2 Lake Shore warrants the Product only if it has been sold by an authorized Lake Shore employee sales representative dealer or original equipment manufacturer OEM 3 The Product may contain remanufactured parts equivalent to new in performance or may have been subject to incidental use 4 The Warranty Period begins on the date of delivery of the Product or later on the date of installation of the Product if the Product is installed by Lake Shore provided that if you schedule or delay the Lake Shore installation for more than 30 days after delivery the Warranty Period begins on the 217 day after delivery 5 This limited warranty does not apply to defects in the Product resulting from a improper or inadequate maintenance repair or calibration b fuses software and non rechargeable batteries c software interfacing parts or other supplies not furnished by Lake Shore d unauthorized modification or misuse e operation outside of the published specifications or f i
120. isting 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 0kG Rea 3kG 2 KG 1 KG 1 kG 2 KG 3 kG Output V Veo r3 2V 1 V P NET 42V 3 To select the default range press the Analog Out key to display the screen to the right Press the Analog Out A or V key to cycle the arrow 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 d
121. ith sensitivities between 0 55 and 1 05 mV kG 100 mA current 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 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 At this time if any of the parameters need to be changed just press the appropriate F key and type in the new value When everything appears correct press F10 to program the probe It takes about 20 seconds to program the probe After the probe is programmed press the Esc key to exit the program Hall Generator
122. laces decimal appropriate to range NOTE The plus sign is displayed but is insignificant The reading is magnitude only 4 31 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 32 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 Configures 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 0r 3 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 Rela
123. lux from these poles is inside of the sample This returned flux tends to decrease the net magnetic field strength internal to the sample yielding 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 uia 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 S 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 fi
124. mproper site preparation or maintenance 6 TO THE EXTENT ALLOWED BY APPLICABLE LAW THE ABOVE WARRANTIES ARE EXCLUSIVE AND NO OTHER WARRANTY OR CONDITION WHETHER WRITTEN OR ORAL IS EXPRESSED OR IMPLIED LAKE SHORE SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY SATISFACTORY QUALITY AND OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE PRODUCT Some countries states or provinces do not allow limitations on an implied warranty so the above limitation or exclusion might not apply to you This warranty gives you specific legal rights and you might also have other rights that vary from country to country state to state or province to province 7 TO THE EXTENT ALLOWED BY APPLICABLE LAW THE REMEDIES IN THIS WARRANTY STATEMENT ARE YOUR SOLE AND EXCLUSIVE REMEDIES 8 EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW IN NO EVENT WILL LAKE SHORE OR ANY OF ITS SUBSIDIARIES AFFILIATES OR SUPPLIERS BE LIABLE FOR DIRECT SPECIAL INCIDENTAL CONSEQUENTIAL OR OTHER DAMAGES INCLUDING LOST PROFIT LOST DATA OR DOWNTIME COSTS ARISING OUT OF THE USE INABILITY TO USE OR RESULT OF USE OF THE PRODUCT WHETHER BASED IN WARRANTY CONTRACT TORT OR OTHER LEGAL THEORY AND WHETHER OR NOT LAKE SHORE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES Your use of the Product is entirely at your own risk Some countries states and provinces do not allow the exclusion of liability for incidental or consequential damag
125. n 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 Inside 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 Alarm Alarm Alarm Alarm Off On Off On
126. nd 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 Leave no unused or unterminated cables attached to the instrument Make cable runs as short and direct as possible 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 T INTRODUCTION BE 1 1 1 0 eric DES 1 1 1 1 Model 450 Gaussmeter System Description nennen 1 2 1 2 jeep 1 3 1 3 EIAS is HE EIE 1 5 1 4 Safety ul EE 1 5 2 INSTALLATION WE 2 0 General 2 1 Inspection and Unpacking ere RR PIRE EEan e err te eie t RR STRSEDBAD
127. nel 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 2 5 1 2 6 2 7 2 4 Lake Shore Model 450 Gaussmeter User s Manual Attachment To A Hall Generator The Model MCBL XX 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 Four tinned wires are provided for connection to the Hall Generator The leads may be soldered directly to these wires The cable comes in two lengths the MCBL 6 is 2 meters 6 feet and the MCBL 20 is 6 meters 20 feet Green Wire Current to Senor Red Wire 6 Foot Cable to Gaussmeter Blue Wire Hall Voltage from Sensor Yellow Wire F 450 2 3 eps Figure 2 3 Model MCB
128. netic field range trigger the alarm Alarm Trigger Inside Outside Query ALMIO Oorl 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 27 ALMLM Input Returned Remarks ALMS Input Returned Remarks ANOD Input Returned Remarks ANOD Input Returned Remarks ANOH Input Returned Remarks ANOH Input Returned Remarks ANOHM Input Returned Remarks ANOL Input Returned Remarks ANOL Input Returned Remarks 4 28 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 Oorl 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 0r ANOD 2 Nothing Sets default analog output status 0 Off 1 On 2 analog output controlled by remote interface
129. ngs A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command strings can be chained together in one communication but they must be separated by a semi colon Only one query is permitted per communication but it can be chained to the end of a command The total communication string must not exceed 64 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting When a command is issued the computer is acting as talker and the instrument as listener The format is command mnemonic gt lt space gt lt parameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 4 3 Terminators must be sent with every message string A query string is issued by the computer and instructs the instrument which response to send Queries are issued similar to commands with the computer acting as talker and the instrument as listener The query format is query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries
130. ns 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 Temperature 5 to 40 C e Maximum relative humidity 80 for temperatures up to 31 C decreasing linearly to 50 at 40 C 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 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 instr
131. nual 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 ANOD must set to Mode 2 before Aocon will function The AOCON command sets bipolar output voltage in percent of full scale Allows a resolution of 0 0196 For safety 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 3 12 3 The command AOCON 50 25 sets output to 50 2596 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 Refer to AOCON command for description 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 Oorl 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 0 thru 7 Returns a single digit corresponding to the current display brightness setting 0 lowest through 7 highest Default
132. o 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 various functions on the keypad Each character is comprised of a 5 by 7 dot matrix See Figure 3 2 Units kG Alarm G gt mG Probe Orientation T Dc Relative Remote Onl DC Only mT PK On On Field Reading uT RMS J Lo s Lower row used for Max Hold MAX shown above and Relati
133. ode Celsius C Scale A temperature scale that registers the freezing point of water as 0 C and the boiling point as 100 C under normal 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 7 coercive force coercive field The magnetic field strength H required to reduce the magnetic induction B ina magnetic material to zero coercivity generally used to designate the magnetic field strength H required to reduce the magnetic induction B ina 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 f
134. 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 96 196 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 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 complet
135. ognized 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 IEEE Interface Example Programs Two BASIC programs are included to illustrate the IEEE 488 communication functions of the instrument The first program was written in Visual Basic Refer to Paragraph 4 1 4 1 for instructions on how to setup the program The Visual Basic code is provided in Table 4 2 The second program is written in Quick Basic Refer to Paragraph 4 1 4 3 for instructions on how to setup the program The Quick Basic code is provided in Table 4 3 Finally a description of operation common to both programs is provided in Paragraph 4 1 4 5 While the hardware and software required to produce and implement these programs not included with the instrument the concepts illustrated apply to almost any application where these tools are available IEEE
136. ositive electron charge with a positive mass hysteresis The dependence of the state of a system on its previous history generally 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 O 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 s
137. ostatic 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 6 2 1 6 2 2 Lake Shore Model 450 Gaussmeter User s Manual Identification of Electrostatic Discharge Sensitive Components Below are various industry symbols used to label components as ESDS H A Ee Handling Electrostatic Discharge Sensitive Components Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and everything that contacts it to ground potential by providing a conductive surface and discharge paths As a minimum observe these precautions 1 De energize or disconnect all power and signal sour
138. ower instrument off then on again to see if it is a soft failure 2 Power computer off then on again to see if the IEEE card is locked up 3 Verify that the address has not been changed on the instrument during a memory reset 4 Check all cable connections Intermittent Lockups 1 Check cable connections and length 2 Increase delay between commands to 50 ms to make sure instrument is not being over loaded Remote Operation 4 13 4 2 4 2 1 4 14 Lake Shore Model 450 Gaussmeter User s Manual SERIAL INTERFACE OVERVIEW The serial interface used in the Model 450 is commonly referred to as an RS 232C interface RS 232C is a standard of the Electronics Industries Association EIA that describes one of the most common interfaces between computers and electronic equipment The RS 232C standard is quite flexible and allows many different configurations However any two devices claiming RS 232C compatibility cannot necessarily be plugged together without interface setup The remainder of this paragraph briefly describes the key features of a serial interface that are supported by the instrument A customer supplied computer with similarly configured interface port is required to enable communication Physical Connection The Model 450 has an RJ 11 connector on the rear panel for serial communication The original RS 232C standard specifies 25 pins but 9 pin 25 pin and RJ 11 connectors are commonly used in the computer industry Fo
139. r 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 larger fields The user defined setpoint becomes the center or zero point of the relative reading and is
140. r controlled conditions which can be repeated with similar results See repeatability Also means that small differences can be detected and measured with confidence See resolution prefixes SI prefixes used throughout this manual are as follows Factor Prefix Symbol Factor Prefix Symbol 1024 yotta Y 107 deci d 10 zetta Z 107 centi C 1018 exa E 107 milli m 10 5 peta P 1075 micro u 102 tera T 107 nano n 10 giga G 10712 pico p 106 mega M 10 15 femto f 108 kilo k 10718 atto a 10 hecto h 107 zepto Zz 10 deka da 1074 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 di
141. r you convenience Lake Shore offers a Model 4001 RJ 11 Cable When combined with either the Model 4002 DB 25 Adapter or Model 4003 DE 9 Adapter this cable assembly can be used to connect the instrument to a computer with the corresponding connector type See Figure 4 4 These adapters are described in Chapter 6 Options and Accessories and are schematically diagramed in Figures 6 6 thru 6 8 Equipment with Data Communications Equipment DCE wiring can be connected to the instrument with a straight through cable However if the interface is for Data Terminal Equipment DTE a Null Modem Adapter is required to exchange the transmit TxD and receive RxD lines The instrument uses drivers to generate the transmission voltage levels required by the RS 232C standard These voltages are considered safe under normal operating conditions because of their relatively low voltage and current limits The drivers are designed to work with cables up to 50 feet in length LSCI Model poesi SERIAL UO to DB 25 Serial Interface To customer supplied Adapter Output on rear of computer with DB 25 Model 450 Serial Interface Connector configured as DCE If the interface is DTE a Null Modem Adapter is required to exchange Transmit and Receive lines The Model 4001 4002 and 4003 are See options available from Lake Shore Use whichever adapter that matches your computer serial interface connector Pin outs are described in Paragraph 6 6
142. 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 an accuracy of 10 1596 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 B 0 0 Error Dev
143. represents the intensity of the field Also know as a Maxwell in the cgs system of units line voltage The RMS voltage of the primary 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 Uo permeability of free space 4r 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 prope
144. rn 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 Instrument model and serial number User name company address and phone number Malfunction symptoms AE O Ww oc 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 Installation 2 1 2 3 2 2 Lake Shore Model 450 Gaussmeter User s Manual DEFINITION OF REAR PANEL CONNECTIONS The Model 450 rear panel consists of the power and fuse assembly IEEE 488 Interface Connector Serial I O Connector Corrected and Monitor Analog Output BNCs and a DA 15 Probe Input Connector See Figure 2 1
145. robe Orientation For Positive Measurement B E NNETERINNS m a 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 0 496 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 chamber 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
146. robe 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 AC DC 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 BI akeShor e 450 Gaussmeter AC DC Peak RMS Local Escape E fel fel 1 I3 Filter Ed Address E Fs EX fa Relative Alarm Set t Sel Baud 1 2 3 v Max Max Zero Select Auto Relative Alarm Analog Reset Hold Probe Range Range n Off n Off Out Enter E x Si E SS an EE Si ES 450_Front bmp Figure 3 1 Model 450 Front Panel Operation 3 4 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 or 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 t
147. rs amp 25 Hard disk controllers ve Keyboard Monitor 9 9 A Mouse W National Instruments GPIB Interfaces AT GPIB TNT Plug and Play Big Network adapters X Ports COM amp LPT ES F F General GPIB Settings Resources y AT GPIB TNT Plug and Play Interface Name cio D GPIB Address Primary DR Secondary NONE ISA PnP Serial Number 004D7F40 r Termination Methods IV Send EOI at end of Write IV Terminate Read on EOS IV Set EO with EDS on Write 8 bit EOS Compare D 05 Byte 8 System devices 1 0 Timeout 10sec Remove Properties Refresh IV System Controller OK Cancel Figure 4 1 GPIB Setting Configuration KE System Properties General Device Manager Hardware Profiles Performance i ett National Instruments GPIB Interfaces Properties 29 x General Device Templates View devices by type m Computer c3 CDROM amp 9 Disk drives S Display adapters Floppy disk controllers 5 Hard disk controllers F Eti E w National Instruments GPIB Interfaces Device Name H H F E E Network adapters Ree 7 Ports COM amp LPT Interface m Termination Methods Timeouts I m H System devices leen J IV Send EO at end of Write fom
148. rs 20 feet long Accessories and Probes 5 1 Lake Shore Model 450 Gaussmeter User s Manual Accessories Continued Model Description j 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 4 MH 2 5 Helmholtz Coil 2 5 inch inner diameter field strength 30 G 9 1 A maximum continuous current 2 A coil resistance 3 Q See Figure 5 8 MH 6 Helmholtz Coil 6 inch inner diameter field strength 25 G 9 1 A maximum continuous current 2 A Coil Resistance 10 Q See Figure 5 9 MH 12 Helmholtz Coil 12 inch inner diameter field strength 12 G 1 A maximum continuous current 2 A Coil Resistance 20 Q See Figure 5 10 Reference Magnets High quality reference magnets are available in transverse flat and axial round configurations Refer to Paragraph 5 5 and see Figure 5 11 MRA 312 100 Axial Reference Magnet 0 312 inch inside diameter 100 G 196 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 XXX MRA 312 2K Axial Reference Magnet 0 312 inch inside diameter
149. rty measured with dc magnetic measurements systems such as a vibrating sample magnetometer extraction magnetometer SQUID magnetometer 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 ao weakly magnetic sample see Magnetization Measured in SI units as A m and in cgs units as emu 1 emu 10 magnetic scalar potential The work which must be done against a magnetic field to bring a eee 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 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 sample 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 g Maxwell M
150. rument that is proportional to its input From an instrument such as a digital voltmeter the output voltage is generated by a digital to analog converter 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 or a 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 control knob cathode The terminal from which forward current flows to the external circuit Anode Cath
151. s 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 O 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 xSTB 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 Status 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 Re
152. set TERM Terminator MAXR Max Reading Query 2 TEM casas t MH SUO 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 Inside 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 de Probe Commands ALMLM Alarm Low Point Multiplier Query ALMS Alarm Status Query FCOMP Set Field Compensation Status ANOD Define Analog Out Default FCOMP Field Compensation Status Query SNUM Probe Serial Number Query ANOD Analog Out Default Query i TCOMP Set Temp Compensation Status ANOH Define Analog Out High Setpoint TCOMP 1 C tion Status Q ANOH Analog Out High Setpoint Query INDES Gr e QN OM SAUS eU y ANOHM Analog Out High Setpoint Multiplier ym i f e Ee GE
153. splay resolution The resolution the physical display of an instrument This is not always the same as the measurement resolution 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 EIA 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 carr
154. ssmeter User s Manual AXIAL PROBES MMA 1802 VH 0 25 dia MMA 1836 VG MMA 1808 WL 80 125 0 004 MMA 2536 WL 36 0 25 10 005 0 25 dia 30 006 0 25 dia 0 025 MCA 2560 WN 50 Figure 5 5 Corrected Accuracy Reading Temp Coefficient Max Temp Coefficient Max cient Max Zeo Calibration Se Range Zero Stem Freq Type Material Range DC 10 to 400 Hz Alum HST 2 DC 0 005 i 0 003 HSE 1 0 030 DC dia 10 to approx 400 Hz 0 016 0 005 HST 2 HST 1 DC Stainless Steel Definition of Lake Shore Axial Probes 0 25 to 0 020 10 kG dia approx 0 25 to 20 kG 0 25 to 30 kG 0 015 per C 10 09 G M C per C 1 to 100 kG 2 to 100 kG 1 5 K to 350 K 0 010 per C Axialeps Accessories and Probes Lake Shore Model 450 Gaussmeter User s Manual FLEXIBLE TRANSVERSE PROBES B 2 5 L i S HE a e SC C O V Ge Cable Length 6 6 feet 0 125 0 020 0 36 0 030 dia T This table is for L 3 inches and S 0 375 inch Corrected Temperature Coefficient Acti Accuracy Operating maximum Model No W T A P See Geet Type of Temperature rea ateria ange Reading Range Zero Calibration 0 25 to MFT 3E03 VH H 0 09 G C 0 015 C wera 0 135 0 025 Ge Ei 30 kG ane max max i i l i approx SE 1 0 15 to 2503 S on ai Jo MFT 3E03 V
155. ter Response data formats are listed along with the associated queries in Paragraph 4 3 The response is sent as soon as possible after the instrument receives the query Typically it takes 10 ms for the instrument to begin the response Some responses take longer Message Flow Control It is important to remember that the user program is in charge of the serial communication at all times The instrument can not initiate communication determine which device should be transmitting at a given time or guarantee timing between messages All of this is the responsibility of the user program When issuing commands only the user program should e Properly format and transmit the command including terminators as one string e Guarantee that no other communication is started for 50 ms after the last character is transmitted e Not initiate communication more than 20 times per second When issuing queries or queries and commands together the user program should e Properly format and transmit the query including terminators as one string e Prepare to receive a response immediately e Receive the entire response from the instrument including the terminators e Guarantee that no other communication is started during the response or for 50 ms after it completes e Not initiate communication more than 20 times per second Failure to follow these simple rules will result in inability to establish communication with the instrument or intermittent failures
156. til Send button pressed Set Flag as false Get Command Clear response display Set all characters to upper case Get out on EXIT Send command to instrument Check to see if query Wait for response Add 1 to timeout if no character Wait for 10 millisecond timer Timeout at 2 seconds Reset timeout for each character Read in one character Add next character to string Get characters until terminators Check if string empty Term 1 Strip terminators Send No Response Put response in textbox on main form Reset holding string Reset timeout counter Do DoEvents Loop Until frmSerial Timerl Enabled False ZeroCount ZeroCount 1 Else ZeroCount 0 strHold frmSerial MSComml Input strReturn strReturn strHold End If Wend If strReturn lt gt Then strReturn Mid strReturn 1 InStr strReturn Else strReturn No Response End If frmSerial txtResponse Text strReturn strHold vn ZeroCount 0 End If Loop End Sub Private Sub Timerl Timer frmSerial Timerl Enabled End Sub False Routine to handle Timer interrupt Turn off timer Remote Operation 4 19 Lake Shore Model 450 Gaussmeter User s Manual 4 2 7 2 Quick Basic Serial Interface Program Setup The serial interface program listed in Table 4 7 works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible running DOS or in a DOS window with a serial interface It uses the COM1 communication port at 9600
157. tive Mode Status REL 0or REL 1 Nothing Sets Relative Mode Status 0 Off 1 On Relative Mode Query REL 0 or 1 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 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 OF 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
158. trength H required to reduce the magnetization M or intrinsic induction in a magnetic material to zero intrinsic induction The contribution of the magnetic material Bi to the total magnetic induction B Bji B pgoH 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
159. trings Refer to Paragraph 4 1 2 4 g Bus Control Commands A Universal Command addresses all devices on the bus Universal Commands include Uniline and Multiline Commands A Uniline Command Message asserts only a single signal line The Model 450 recognizes two of these messages from the BUS CONTROLLER Remote REN and Interface Clear IFC The Model 450 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 These 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 Remote Operation Lake Shore Model 450 Gaussmeter User s Manual Bus Control Commands Continued 4 1 2 2 4 1 2 3 4 1 2 4 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
160. ty 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 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 V yg B sin 0 where V Hall voltage mV Yg Magnetic sensitivity mV kG at a fixed current B Magnetic field flux density kilogauss 0 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 ACT
161. ument 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 Alternating or direct current power line Three phase alternating current power line Earth ground terminal Caution or Warning See instrument documentation Background color Yellow Symbol and outline Black Protective conductor terminal gt E p Frame or chassis terminal On supply Off supply f Fuse O
162. until the proper voltage indicator shows through the window Verify the proper fuse value Re assemble the line input assembly in the reverse order 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 1095 5 Voltage 50 60 Hz 40 VA MAX FUSE DATA 100 120 V 0 5A 0 25 x 1 25 in T 2201240 V 0 25A 5x20mmT 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 protection 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 po
163. utput Control MOde nb t me IR Le CHR EORR er RSS 3 11 3 13 Locking and Unlocking the Keyboard 3 12 3 14 Factory Default Settings iie es ERU tr D Ur odere o Elbe lite eases Le do tein Ea 3 12 3 15 Probe eene Ee 3 13 3 15 1 Ghangihg Probes eese ee nere nU be ER Eu 3 13 3 15 2 Probe e Etuien WEE 3 15 3 Probe Operation 3 15 4 Probe Accuracy Considerations sess nennen nnne 3 15 3 16 Fast Data MOG ec 6i o rette toe itat Qt eben Ere spuria Drees 3 16 4 COMPUTER INTERFACE OPERATION e eeeeeeeeeeeetne nene s nnnm nne tnn nnnm ani tn aset s ss tn sse onono sn ases sss sn ases assa sanas 4 1 4 0 GENERAL en DIRIGERE INEO toni e DUCES 4 1 4 1 IEEE 488 INTERFAGE 2 La pectet ette Lid etae Le Pe ect dto de ade e eee dee e 4 1 4 1 1 Changing IEEE 488 Interface Parameters A 4 2 4 1 2 IEEE 488 Command Structutte eremo Dee te rd e e eas retin De ree erica 4 2 4 1 2 1 Bus Gontrol Gommarids 2 eite eth e ER t c tee UD e ee 4 2 4 1 2 2 Common ComMandS 5 ne m i e eei ie e Eu p f b hee des 4 3 4 1 2 3 Device SpecificGommlands 4 2 ci e e eie RE REOR EE IR ENS 4 3 4 1 2 4 Message Stings soren Deer oc cec ene ane enced et er e ege Gielen RL 4 3 4 1 3 Status Registers euet eie RH dte REI etu Tenet ge ee uet e ROO ucc e Rep eet er 4 4 4 1 3 1 Status Byte Register and Service Request Register sssssssseeee 4 4 4 1 3 2 Standard Event Status Register
164. ve 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 must 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 t
165. wer cord af ON gt 0 5 AT 250 V 0 25 A T 250 V 0 25 x 1 25 inches 5 x 20 mm 100 120 V 220 240 V Re assemble line input assembly in reverse order Verify voltage indicator in the line input assembly window Connect instrument power cord oono Turn power switch On I 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 Input Analog Signal No Connection No Connection ITEMP ITEMP No Connection No Connection lc Input Analog Signal Ground No Connection Digital Ground C450 6 2 ops 5 Volts Power Output To Probe EEPROM EE CLK Output To Probe EEPROM EE DATA Serial Input From Probe EEPROM lc 1 2 3 PROBE INPUT M 6 7 8 9 DA 15 Connector View looking at rear panel Figure 6 2 DA 15 PROBE INPUT Connector Details ANALOG OUTPUTS Corrected Monitor PIN DESCRIPTION 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 TI Serial In RxD Serial In RxD Te Serial Ground Serial Ground Serial Out TxD Serial Out TxD
166. wisted 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 SRQ Ground Wire Twisted pair with ATN Logic Ground Figure 6 5 IEEE 488 Rear Panel Connector Details 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 D E w TxD YELLOW D lt Gnd GREEN i e Gnd RED uc A RxD BLACK a o Figure 6 6 Model 2001 RJ 11 Cable Assembly Wiring Details CONNECTOR NOT USED For Customer supplied computer with DB 25 Serial Interface Connector configured as DCE If the interface is DTE a Null Modem Adapter is required to exchange Transmit and Receive lines RECEPTACLE DB9 CONNECTOR NOT USED For Customer supplied computer with DE 9 Serial Interface Connector configured as DTE 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
167. x A cgs electromagnetic unit of magnetic flux equal to the magnetic flux which produces an electromotive force of 1 abvolt in a circuit of one turn link the flux as the flux is reduced to zero in 1 second at a uniform rate 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 4x x 10 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 swit
168. xTST 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 xWAI 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 cannot be embedded between other commands 4 24 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
169. xed reference input Note Drift is usually expressed in percent of the maximum rated value of the variable being measured dynamic data 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 free
170. y 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 to 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 Max Hold feature 0 Off 1 On Works with MAXC MAXR and MAXRM commands Max Hold Query MAX Oorl Queries Max Hold status 0 Off 1 On Works with MAXC MAXR amp MAXRM 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 5 digits and decimal point P
171. zing point of water as 32 F and the boiling point as 212 F under normal atmospheric pressure See Temperature for conversions flux 6 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 4x 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 a A lota 1 I Rho p P Beta B B Kappa K K Sigma o X
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