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Lake Shore Model 425 Gaussmeter Manual

1. ference magnetomotive U F gilbert Gb 10 47 ampere A force Magnete ned strengur H oersted Oe Gb cm 103 47 A mf magnetizing force Volume magnetizationg M emu cm3h 103 A m Volume magnetization 47M G 10347 A m Magnetic polarization intensity of magnetiza J emu cm3 4T x 10 4 T Wb m i tion cle 1 A m2 kg Mass magnetization o M emu g An x 107 Wb m kg A m2 joule per 3 Magnetic moment m emu erg G 10 tesla J T Magnetic dipole moment j emu erg G 4n x 10 10 Wb m2 ee dimensionless Henry per meter H Volume susceptibility XK enmia 47 2 x 107 m Wb A m 4r x 103 m3 kg M tibilit K 3 9 Mass susceptibility Ko Ks cm3 g emu g 472 x 1020 H m2 kg no 41 x 10 6 m3 mol Molar susceptibility YF mois Tee cm3 mol emu mol 47 x 10 3 H m mol Permeability u dimensionless 4T2 x 107 H m Wb A m Relative permeabilityi Hr not defined dimensionless Volume energy density W ergicm3 10 1 J m3 energy productk Demagnetization factor D N dimensionless 1 41 dimensionless TABLE A 1 Conversion from CGS to SI units u Lake Shore CRYOTRONICS www lakeshore com 66 Appendix A Model 425 Gaussmeter
2. 16 CHAPTER 2 Background Model 425 Gaussmeter 3 1 General 17 Chapter 3 Installation 3 1 General 3 2 Inspection and Unpacking 3 3 Rear Panel Definition CAUTION This chapter provides general installation instructions for the Model 425 gaussmeter Please read this entire chapter before installing the instrument and powering it on to ensure the best possible performance and to maintain safety For instrument operat ing instructions refer to Chapter 4 and Chapter 5 For computer interface installation and operation refer to Chapter 6 Inspect shipping containers for external damage before opening them Photograph any container that has significant damage before opening it Inspect all items for both visible and hidden damage that occurred during shipment If there is visible damage to the contents of the container contact the shipping company and Lake Shore immediately preferably within five days of receipt of goods for instruc tions on how to file a proper insurance claim Lake Shore products are insured against damage during shipment but a timely claim must be filed before Lake Shore will take further action Procedures vary slightly with shipping companies Keep all damaged shipping materials and contents until instructed to either return or discard them Open the shipping container and keep the container and shipping materials until all contents have been accounted for Check off each item on the packing list as it
3. Do not bend from tip of probe Flexible transverse probe The tip is maximum bend angle VERY FRAGILE FIGURE 3 4 Maximum flexible transverse probe bend radius The probe should only be held in place by securing it at the handle Do not apply force to the probe stem The stems are not designed to handle clamping forces Clamping to the stem can also strain the sensor and alter the probe calibration and excessive force may destroy the Hall sensor Lake Shore offers two probe stands for mounting your probe FIGURE 3 5 shows a probe properly mounted using a Lake Shore probe P N 4030 12 or 4030 24 stand 3 6 3 Probe Operation 3 6 3 Probe Operation 21 FIGURE 3 5 Proper mounting of the probe 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 s circular face FIGURE 3 6 Lake Shore logo towards north pole N HE e 32 AA Transverse probe orientation 5 for positive measurement B Ed ENS SRNR d9 3 L3 Axial probe orientation for positive measurement FIGURE 3 6 Probe orientation for positive measurement For best results the instrument and probe should warm up for at least 5 min before zeroing the probe and atleast 30 min for rated accuracy Also the
4. In DC mode and RMS narrow band mode the monitor output has the frequency response shown in FIGURE 5 3 The output will work down to DC levels but rolls off above 400 Hz due to the product detector filter This filter exists to reduce high frequency noise generated by the 5 4 kHz carrier Refer to section 2 2 for a sys tem block diagram 2 4 10 20 30 Error 50 60 1 10 100 400 1000 Frequency Hz FIGURE 5 3 Monitor output DC and narrow band mode frequency response In RMS wide band mode the monitor output has a frequency response shown in FIGURE 5 4 Here the frequency responds up to 10 kHz but rolls off below 50 Hz because the input is AC coupled 0 5 0 5 10 50 100 1000 10000 Frequency Hz FIGURE 5 4 Monitor output wide band mode frequency response The Model 425 has several capabilities that allow the best possible measurements with Lake Shore probes These firmware based features work in tandem with probe calibration and programming to ensure accurate repeatable measurements and ease of setup Many of the features require probe characteristics stored in non vola tile memory during calibration that are located in the probe connector mw Lake Shore www lakeshore com CRYOTRONICS 38 CHAPTER 5 Advanced Operation 5 4 1 Probe Serial Number 5 4 2 Field Compensation 5 4 3 Extension Cable 5 4 4 Clear Zero Probe Calib
5. calibrated in a way to provide the most accurate DC readings The gaussmeter reads the probe information on power up or any time the probe is changed to allow hot swapping of probes Critical probe information can be viewed onthe front panel and read over the computer interface to ensure proper system con figuration The Model 425 is only half the magnetic measurement equation For the complete solution Lake Shore offers a full complement of standard and custom Hall effect probes in a variety of sizes and sensitivities One often standard Hall probes is included with the Model 425 Refer to page 5 for details on the Hall probes you can choose to receive with the Model 425 1 3 4 Extension Cable 1 3 5 Hall Effect Generators Magnetic Field Sensors 1 4 Display and Interface Features 1 3 4 ExtensionCable 3 The complex nature of Hall effect measurements makes it necessary to match exten sion cables to the probe when longer cables are needed Keeping probes and their extensions from getting mixed up can become a problem when more than one probe is used The Model 425 alleviates most of the hassle by allowing you to match probes to extension cables in the field Stored information can be viewed on the front panel and read over the computer interface to ensure proper mating The Model 425 will operate with a discrete Hall effect generator when a suitable probe is not available You can program the nominal sensitivity and serial number i
6. contacts are made This entity is normally called a Hall plate In its simplest form the Hall plate is a conductor rectangular in shape and of fixed length width and thick ness 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 on the Hall plate the diameter of which is equal to the plate width This circle is considered an approximation of the active area FIGURE 2 2 illustrates an image of the approxi mate active area mw Lake Shore www lakeshore com CRYOTRONICS 10 CHAPTER 2 Background Approximate active area VH VH B FIGURE 2 2 Approximate active area 2 4 2 Temperature There are two technically different temperature coefficients that always affect a Coefficients gaussmeter probe the temperature coefficient of zero and the temperature coeffe cient of sensitivity section 2 4 2 1 and section 2 4 2 2 Under normal usage reading a magnetic field itis virtually impossible to separate the effect of each The Model 425 gaussmeter does not possess circuitry to allow compensation for these temperature errors Thus a useroperating a probe in a variable temperature environment must be aware that both errors exist and what the maximum effect could be The temperature coefficients are repeatable for an individual probe A user can pre measure the changes and manually correct the data for zero and sensitivity e
7. www lakeshore com CRYOTRONICS 40 CHAPTER 5 Advanced Operation Model 425 Gaussmeter 6 1 General 41 Chapter 6 Computer Interface 6 1 General 6 2 USB Interface 6 2 1 Physical Connection 6 2 2 Hardware Support Operation This chapter provides operational instructions for the computer interface for the Lake Shore Model 425 gaussmeter The computer interface provided with the Model 425 permits remote operation its commands are detailed in section 6 3 The Model 425 USB interface provides a convenient way to connect to most modern computers as a USB interface is provided on nearly all new PCs as of the writing of this manual The USB interface is implemented as a virtual serial communication port connection This implementation provides a simple migration path for modifying existing RS 232 based remote interface software It also provides a simpler means of communicating than a standard USB implementation The Model 425 has a B type USB connector on the rear panel This is the standard connector used on USB peripheral devices and it allows a common USB A type to B type cable to be used to connect the Model 425 to a host PC The pin assignments for A type and B type connectors are shown in section 8 7 The maximum length of a USB cable as defined by the USB 2 0 standard is 5 m 16 4 ft This length can be extended using USB hubs every 5 m 16 4 ft up to 5 times for a maximum total length of 30 m 98 4 ft The USB
8. 425 to the computer 2 Turnonthe Model 425 3 When the Found New Hardware wizard appears select Locate and install driver software recommended 4 fUserAccount Control UAC is enabled a UAC dialog box may appear asking if you want to continue Click Continue 5 TheFound New Hardware wizard should automatically connect to Windows Update and install the drivers If the Found New Hardware Wizard is unable to connect to Windows Update or find the drivers a message to Insert the disc that came with your Lake Shore Model 425 will be displayed Click Cancel and refer to section 6 2 3 3 to install the driver from the Internet 6 Whenthe Found New Hardware wizard finishes installing the driver a confirma tion message stating the software for this device has been successfully installed will appear Click Close to finish installation 6 2 3 2 Installing the Driver From Windows Update in Windows XP 1 Connectthe USB cable from the Model 425 to the computer 2 Turn on the Model 425 3 Whenthe Found New Hardware wizard appears select Yes this time only and click Next 4 Select Install the software automatically Recommended and click Next 5 TheFound New Hardware wizard should automatically connect to Windows Update and install the drivers If the Found New Hardware wizard is unable to connect to Windows Update or find the drivers a message saying Cannot install this hardware will be displayed Click Cancel and
9. Calibration 2 6 4 Off Axis Effects 2 6 5 Induced AC Voltage 2 7 Cryogenic Measurement Considerations 2 7 1 Thermal Stresses 2 7 2 Temperature Coefficients Model 425 Gaussmeter Tolerance of instrument probe and magnet must be considered for making critical measurements The accuracy of the gaussmeter reading is typically 0 20 of read ing and 0 05 of range but the absolute accuracy readings for gaussmeters and Hall probes is a difficult specification to give because all the variables of the mea surement are difficult to reproduce Differences in alignment and positioning will degrade measurement accuracy and repeatability Finally the best probes have an accuracy of 0 10 This implies that the combined accuracy of a magnetic field measurement will not reliably be better than 0 20 of reading and is likely to be 0 30 or higher In the unusual circumstance where a large off axis field is present when making a measurement this off axis field generates an error An example of this is when trying to read a small transverse field in a high field solenoid This error occurs because there are geometric limitations in the manufacturing of the sensors Additional errors can be caused by the planar Hall effect and magneto resistance The amount of reading error can be as much as a few percent of this off axis field This is significant when the off axis field is many times larger than the field of interest There is no way to dis
10. In this instance finished magnets are installed into a motor assembly and then they are verified using the Model 425 to measure the field magni tude and field polarity In this example the alarm function will be setup the same asthe previous example with the exception of using the algebraic setting instead of the magnitude setting The algebraic setting is chosen since the orientation matters in this application The low setpoint will be set to 0 9 kG and the high setpoint will be set to 1 1 kG After the assembly is placed on the test fixture if the measured field is between the high and low alarm setpoints the part is considered conforming and the display will indicate a Pass condition If the measured field is 1 0 kG the assembly is non conforming and the display will indicate Fail Low In this case the magnitude of the field was cor rect but the magnet was installed with the wrong orientation Pass alarming Fail low Fail high non alarming non alarming 3 kG 2 kG 1 kG 0 kG 1 kG 2 kG 3 kG Alarm triggered by readings OUTSIDE Lowalarm High alarm user defined setpoints in algebraic mode point point FIGURE 5 2 Alarm on with algebraic and outside settings 5 2 7 3 Monitoring a Static Field In this application an electromagnet is used to generate a static field for an experi ment This field is monitored using the Model 425 The results of the experiment are valid only if the field remains stable wit
11. No connection 8 Relay 1normallyopen 21 No connection 9 Relay 1 common 22 No connection 10 Relay 1 normally closed 23 No connection 11 Internal use only 24 No connection 12 Internal use only 25 No connection 13 Internal use only TABLE 3 3 Auxiliary I O connector details Model 425 Gaussmeter 3 8 Attaching a Hall Generator to the Model 425 AWARNING CAUTION 3 8 Attachinga Hall Generatortothe Model 425 23 Monitor output the Model 425 has a monitor output that provides an analog represen tation of the reading and is corrected for probe offset and nominal sensitivity The monitor output has an output scale of 3 5 V which is proportional to the measured field on the selected range You can connect an oscilloscope or data acquisition sys tem to the monitor out to analyze the readings Relay 1 the Model 425 has one mechanical relay designated as relay 1 The relay is associated with the high and low alarms or you can manually control it Refer to the website http www lakeshore com products gaussmeters model 425 gaussme ter pages Specifications aspx for voltage and current ratings for the relay Refer to section 5 2 6 for more operational details Connecting a Hall generator to the Model 425 requires a Lake Shore Model HMCBL 6 2 m 6 ft or HMCBL 20 6 m 20 ft cable assembly which are sold separately Each Hall generator purchased from Lake Shore will come with a nominal field sensitivity value Howeve
12. RMS TT I Lm a E SE Soan Max or relative setpoint DC MX RMS SP FIGURE 4 2 Front panel display definition 4 3 1 Display Units 4 3 2 Display Annunciators 4 4 Display Setup 4 4 1 Field Units Parameter 4 4 2 Display Contrast 4 5 DC and RMS Measurement Modes 4 3 1 DisplayUnits 27 ove 77 NN G Field in gauss T Field in tesla Oe Field in oersted A m Field in ampere meter Resistance in ohms TABLE 4 2 Display units There are display annunciators that appear as necessary to indicate additional infor mation Display annunciators are visible when their associated feature is enabled Annunciator Function DC RMS DC or RMS mode readings MX Indicates the max hold value it is displayed on the lower row E Indicates the relative reading it is displayed on the upper row SP Indicates the relative setpoint value 4 On steady when the alarm function is on blinks when in the alarming state Pass Lu Fail Hich Shown when the sort parameter is enabled indicates when a voli measurement passes or fails the user specified magnet test Fail Low TABLE 4 3 Display annunciators This section describes how to set up the field units and display contrast The field units parameter determines which units are used to display the measured field maximum field and relative field readings Menu navigation Units gauss tesla oersted or ampere meter Default gauss Inte
13. RMS to DC converter The signal is then sent into the A D converter The digitized data is then sent to the microprocessor The monitor output will provide an unfiltered AC voltage proportional to the mea sured AC field Refer to section 4 5 2 2 for the procedure to set the AC wide band mode The Model 425 has a monitor output that provides an analog representation of the reading and is corrected for probe offset and nominal sensitivity This monitor output makes it possible to view the analog signal which has not been digitized The monitor output can be connected to an oscilloscope or data acquisition system for analysis A magneticfield can be envisioned as lines of force measured in maxwells Mx In the cgs system magnetic flux 0 is the Mx where 1 Mx 1 line of flux In the SI system magnetic flux is the weber Wb where 1 Wb 108 Mx Flux density is the number of flux lines passing perpendicular through a plane of unit area A The symbol for flux density is B where B A The cgs system measures flux density in gauss C where 1G 1 Mx cm2 The SI system measures flux density in tesla T where 1 T 1 Wb m2 Flux density is important when magnet systems concentrate flux lines into a specific area like the pole pieces of an electromagnet Forces generated on current carrying wires like those in a motor armature are proportional to flux density Saturation of magnetic core material is also a function of flux density Ad
14. audible signal that the magnet passed the test In this example the alarm sort parameter is chosen to also show a pass or fail condition on the Model 425 display The low alarm setpoint will be set to 0 9 kG 0 09 T and the high alarm setpoint will be setto 1 1 kG 0 11 T The beeper will sound and the display will indicate a Pass condition ifthe magnet has a field magnitude between the two setpoints regardless of field polarity If the field magnitude is less than 0 9 kG the dis play will indicate Fail Low and if itis greater than 1 1 kG it will indicate Fail High Since the alarm is configured with the magnitude setting a reading between 0 9 kG and 1 1 kG will also indicate a Pass condition since the orientation is not a fac tor in this scenario mw Lake Shore www lakeshore com CRYOTRONICS 36 CHAPTER 5 Advanced Operation Model 425 Gaussmeter Pass Pass alarming alarming Failhigh Fail low Fail high non alarming s BE non alarming non alarming 3 kG 2 kG 1 kG 0 kG 1kG 2 kG 3 kG Alarm triggered by readings Lowalarm point EE OUTSIDE user defined High alarm point setpoints in magnitude mode FIGURE 5 1 Alarm on with magnitude and outside settings 5 2 7 2 Testing a Magnet Installed in an Assembly Another common application is testing magnets installed into an assembly In this case the orientation ofthe magnet matters An example ofthis isthe magnets used in a motor assembly
15. for 3 s filter band narrow filter band wide Default filter band narrow Interface command RDGMODE mw Lake Shore www lakeshore com CRYOTRONICS 30 CHAPTER 4 Operation 4 5 3 Autorange and Range Selection Model 425 Gaussmeter 4 5 2 1 Narrow Band Mode The narrow band mode has been designed to measure AC fields ranging from 10 Hz to 400 Hz The monitor output will provide an AC voltage proportional to the measured AC field where 3 5 V equals full scale for the selected range 10 0 10 20 30 Error 40 50 60 1 10 100 400 1000 Frequency Hz FIGURE 4 3 Narrow band mode frequency response plot 4 5 2 2 Wide Band Mode The wide band mode has been designed to measure fields of higher frequencies expanding the instrument s capability to measure AC fields ranging from 50 Hz to 10 kHz The monitor output will provide an unfiltered AC voltage proportional to the measured AC field where 3 5 V equals full scale for the selected range 0 0 0 4 1 0 1 5 Error 2 0 2 5 3 0 I 3 0 10 50 100 1000 10000 Frequency Hz FIGURE 4 4 Wide band mode frequency response plot The Model 425 is equipped with an autoranging feature that will automatically select the appropriate field range for the measured field In some cases it may be desirable to manually select the field range Autorange is not
16. in approximately O 5 s It is a moving average filter so it does not change the reading update rate If the filter is turned on all reading values are filtered including the relative reading and all fea tures will use the filtered reading including maximum reading and alarms The filter has no effect on the monitor output The filter function is used to quietthe display and make it more readable when the probe is exposed to a noisy field The filter also acts to quiet noise within the instru ment making an additional digit of usable resolution available to 43 4 digits with the filter on Care should be taken when using the filter on changing fields because it may level off peaks and slow the response of the instrument In AC mode the filter function is always active to help quiet the reading Although the filter is active in AC the resolution remains 33 4 digits Menu navigation In DC mode DC RMS press and hold for 3 s Filter on off Default on Interface command RDGMODE 4 5 1 2 DCOperation Zero Probe The zero probe function cancels out the zero offset of the probe or small DC magnetic fields It is normally used in conjunction with the zero gauss chamber but may also be used with an unshielded probe registering Earth s local magnetic field The zero probe function should be used any time a probe is changed when operating in condi tions such as significant temperature change and periodically during normal use To cancel
17. instrument uses a 100 mA 5 4 kHz square wave excitation current This type of excitation provides the benefit of noise cancellation characteristics of the product detector but it limits the maximum field frequency of the Model 425 to approximately 400 Hz The voltage that is generated by the Hall sensor goes through an AC coupled pro grammable gain stage From there it passes through the product detector for demod ulation a low pass filter and an RMS to DC converter before it is sent into the A D converter The digitized data is then sent to the microprocessor The monitor output will provide an AC voltage proportional to the measured AC field Refer to section 4 5 2 1 for the procedure to set the narrow band AC measurement mode Wide band mode in this mode the instrument uses a 100 mA DC excitation current to drive the Hall sensor This excitation type provides the greatest frequency range for AC RMS measurements up to 10 kHz Since the signal doesn t pass through the prod uct detector and low pass filter it has a higher noise floor than narrow band mode mw Lake Shore www lakeshore com CRYOTRONICS 8 CHAPTER 2 Background 2 2 3 Monitor Output 2 3 Flux Density Overview 2 3 1 What is Flux Density 2 3 2 How Flux Density B Differs from Magnetic Field Strength H Model 425 Gaussmeter The voltage that is generated by the Hall sensor goes through an AC coupled pro grammable gain stage and is sent directly to an
18. refer to section 6 2 3 3 to install the driver from the Internet 6 Whenthe Found New Hardware wizard finishes installing the driver a confirma tion message stating the wizard has finished installing the software for Lake Shore Model 425 gaussmeter will appear Click Finish to complete the installation 6 2 3 3 Installing the Driver From the Internet The Model 425 USB driver is available on the Lake Shore website To install the driver it must be downloaded from the website and extracted Use the procedure in section 6 2 3 3 1 through section 6 2 3 3 3 to download extract and install the driver using Windows Vista and XP 6 2 3 Installingthe USB Driver 43 6 2 3 3 1 Download the driver 1 Locate the Model 425 USB driver on the downloads page on the Lake Shore website 2 Right click on the USB driver download link and select save target link as 3 Save the driver to a convenient place and take note as to where the driver was downloaded 6 2 3 3 2 Extract the driver The downloaded driver is in a ZIP compressed archive The driver must be extracted from this file Windows provides built in support for ZIP archives If this support is disabled a third party application such as WinZip or 7 Zip must be used For Windows Vista 1 Right click on the file and click extract all 2 An Extract Compressed Zipped Folders dialog box will appear It is recom mended the default folder is not changed Take note of this fold
19. s cred cen EE AERE ER ii Res dauid 2 Irisereme E Prope Festo 2 1 3 1 Probe Field COMPCNS AHO ssa aadesena cid errori 2 L32 Probe MOMAN aote toad E e eat e E EE EEN SUPR EM INS 2 1 3 3 The Prope Connection nicer sacesnanenas ee CAI 2 lo PANON ADIE rici 3 1 3 5 Hall Effect Generators Magnetic Field Sensors 0 cece cece eee ees 3 Display ald RIGLE E RARO at PR NN RUP S Fea WS 3 ONE KEV rele E E EE 3 1 4 2 Alarm Relay and Sort ssaa 3 LAS Monitor OULDUE clin 3 1 4 4 Computer Interface acresubes pac VUE apdR Euri JO CIO PEDE QUE RU ERO ai chu aute Cato Tra 4 1 4 5 Model 425 Rear Panel 1 25 5 ru rhcratiRo beh RR br y ERE RR ERR KR 3G daa a 4 Hal PROBE Se ECHO prin dua Meaux IE DEDE NE 4 MCE 42S Specifications rarr dite denn io opas dubi ou MER ES 4 Safety Summary and Symbols usua vivid e ve bp Euobde x tc aaa 5 cc M tas 7 Wilsec MASS d I MM 7 2 Ll DEMS8SSUISITISIID stili DEMEURE HI sailor 22 9 M TOTHEOT EOD EDITO Pose ez ins ode oap Ea sU aude phonies desi SH UA d 8 Fux Dens V OVEVIEW MT 8 2 3 1 Wpatis Fux Density Losada dudo ica t aria Rc PRU ea Pb he dae au 8 2 3 2 How Flux Density B Differs from Magnetic Field Strength H 8 Hall Measurement TiO sotass d red tado de vu mbar redeo e a ow ada 9 2911 JAGUVEATB uisscuscisuiudobtureniadeUA iaia nd 9 2 4 2 Temperature Coefficients 25 kar
20. the defective Product is shipped freight prepaid back to Lake Shore Lake Shore will at its option either repair or replace the Product if it is so defective with out charge for parts service labor or associated customary return shipping cost to the Purchaser Replacement for the Product may be by either new or equivalent in performance to new Replacement or repaired parts or a replaced Product will be warranted for only the unexpired portion ofthe original warranty or 90 days whichever is greater 2 Lake Shore warrants the Product only if the Product has been sold by an authorized Lake Shore employee sales representative dealeror an authorized Lake Shore original equipment manufacturer OEM 3 The Product may contain remanufactured parts equivalent to new in performance or may have been subject to incidental use when itis originally sold to the Purchaser 4 The Warranty Period begins on the date the Product ships from Lake Shore s plant 5 This limited warranty does not apply to defects in the Product resulting from a improper or inadequate installation unless OT amp V services are performed by Lake Shore maintenance repair or cali bration b fuses software power surges lightning and non rechargeable batteries c software interfacing parts or other sup plies not furnished by Lake Shore d unauthorized modification or misuse e operation outside of the published specifications f improper site preparatio
21. 2 Rack mount kit for one 1 2 rack gaussmeter in 483 mm 19 in rack RM 2 Rack mount kit for two 1 2 rack gaussmeter in 483 mm 19 in rack 4030 12 Hall probe stand 305 mm 12 in post 4030 24 Hall probe stand 610 mm 24 in post TABLE 7 4 Accessories available mw Lake Shore www lakeshore com CRYOTRONICS 56 CHAPTER 7 Probes and Accessories 7 4 Rack Mounting The Model 425 can be installed into a 483 mm 19 in rack mount cabinet using the optional Lake Shore Model RM 1 2 rack mount kit or the Model RM 2 dual rack mount shelf The rack mount kit contains mounting ears panel handles and screws that adapt the front panel to fit into a 88 9 mm 3 5 in tall full rack space Refer to FIGURE 7 1 for installation details Ensure that there is a 25 mm 1 in clearance on both sides of the instrument after rack mounting Refer to NOTE NOTE Customer must use 5 e4 in 2 mm hex key to remove four existing screws from sides of instrument Unit on right side mounting shown Unit on left side also possible Item Description Rack mount ear 107 440 Rackmountsupport 107 442 Rack mount panel 107 432 Rack mounthandle 107 051 01 Screw 6 32x15in 0 035 FHMS Phillips Screw 8 32 x 3s in 0 081 FHMS Phillips FIGURE 7 1 Model RM 1 rack mount kit Model 425 Gaussmeter 7 5 Probe Accessories 7 6 Hall Generator Additional accessories are available that may be desirable A list of accessories avail 7 5 Pr
22. 3 Click the Go to the download bar and follow the prompts that are provided on the screen for you TABLE 8 6 describes the updates made to the temperature controller in each version Instrument Features added firmware version 1 2 Fixed an issue with the monitor output when switching between AC and DC modes TABLE 8 6 Instrument firmware updates Refer to the following sections when contacting Lake Shore for application assistance or product service Questions regarding product applications price availability and shipments should be directed to sales Questions regarding instrument calibration or repair should be directed to instrument service Do not return a product to Lake Shore without a Return Material Authorization RMA number section 8 10 2 The Lake Shore Service Department is staffed Monday through Friday between the hours of 8 00 AM and 5 00 PM EST excluding holidays and company shut down days Contact Lake Shore Service through any of the means listed below However the most direct and efficient means of contacting is to complete the online service request form at http www lakeshore com sup serf html Provide a detailed description of the problem and the required contact information You will receive a response within 24 hours or the next business day in the event of weekends or holidays If you wish to contact Service or Sales by mail or telephone use the following Lake Shore Cryotronics e Instrume
23. 3 4 1 Line Voltage 3 4 2 Power Cord AVE ile Model 425 Gaussmeter TUS PASV IEEE T A OR Cre Re Ane RI AA I BR TR LITE E FE TIE AR CTS ETNO OM POT a EI RISO EA eee et RENEE aa 5 T xy ATRIA AZIO VARI IA RL ENEA VEY Aa ONT ee A x RICE SEIT AES SA RITO ARL CRG pe LATE IRSA NE RANSIE x Loe PL E JL gt une CE A WARNING 100 240 V RoHS Shock hazard 50 60 Hz COMPLIANT No user servicable parts 40 VA MAX inside Refer servicing to trained service personnel FIGURE 3 1 Model 425 rear panel Includes the IEC 320 C14 line cord receptacle and instrument power switch Line input assembly Refer to section 3 4 USB interface Standard B type USB connector Referto section 6 2 and see 8 3 25 pin D sub that provides access to the monitor output and relays Refer to section 3 7 15 pin D sub for probes or Hall generator cables Refer to section 3 6 for additional probe considerations Auxiliary I O Probe input TABLE 3 1 Rear panel connector descriptions see FIGURE 3 1 for the corresponding image This section describes how to properly connect the Model 425 to line power Please follow these instructions carefully to ensure proper operation of the instrument and the safety of operators COMPLIANT FIGURE 3 2 Line input assembly The Model 425 will operate between the range of 100 VAC to 240 VAC with 50 Hz or 60 Hz configurations so that it can be operated from line power
24. 425 Gaussmeter This section defines and discusses things to consider when selecting a probe Because accessing the field is part of the challenge when selecting a probe field ori entation dictates the most basic probe geometry choice of transverse versus axial Other variations are also available for less common more challenging applications Listed below are the standard configurations for HSE and HST probes UHS probes require special construction that is not described here m Transverse most often rectangular in shape transverse probes measure fields per pindicular to their stem width They are useful for most general purpose field measurements and are essential for work in magnet gaps Several stem lengths and thicknesses are available as standard probes m Axial usually round axial probes measure fields perpindicular to their end They can also be used for general purpose measurements but are most commonly used to measure fields produced by solenoids Several stem lengths and diame ters are available as standard probes m Flexible with a flexible portion in the middle of their stem flexible probes have an active area at the tip that remains rigid and somewhat exposed This unique fea ture makes them significantly more fragile than other transverse probes Flexible probes should only be selected for narrow gap measurement applications m Tangential these probes are transverse probes designed to measure fields parallel to and ne
25. 8 1 Parameter Default Measurement mode DC DC filter On RMS measurement band Narrow Measurement Autorange On Field compensation On Max hold Off Relative Off Brightness 10 Display gt Field units Gauss Alarm off Alarm mode Magnitude Alarm trigger Outside Alarm and relay Alarm audible On Alarm sort On Relay off Keypad locking Mode Unlocked TABLE 8 1 Default parameter values Menu navigation Escape press and hold for 3 s Interface command DFLT 8 5 2 Product Information 8 6 Error Messages 8 7 Rear Panel Connector Definitions 8 5 2 Productinformation 61 Product information for your instrument is also found in the Factory Reset menu The following information is provided BH Firmware version m Serial number The messages listed in TABLE 8 2 appear on the instrument display when it identifies a problem during operation The messages are divided into three groups Instrument hardware messages are related to the instrument s internal circuits or non volatile memory If one of these messages persists after power is cycled the instrument requires repair or recalibration Measurement messages are most often associated with over field conditions caused by an improperly selected field range excessive noise on the measurement leads or a missing or invalid probe If these messages per sist after proper configuration the instrument may require repair Illegal operation m
26. CHOM sasso denotare 19 Probe Handling and Operation esist 20 Lol Probe HONG sissi arri 20 3 6 2 Probe uUi a 20 3 6 3 Probe Operation aus rada a bud tuat iodato SU ord dar QUIDNE Iq 21 RIDIRE siii eiA 22 Attaching a Hall Generator to the Model 425 sss 23 Lo POT sosia a EEE A E ratio artrosi da dia 24 foc sente 25 Front Panel DESCDUO Mics sea sri sate ating yee ead n 6 Feder eni la 25 4 2 1 Keypad Definition irritare 25 4 2 2 General Keypad Operation ccc ccc cece cece es 26 DISD ay DeMMTOM ueaess venenat atti cada rebus dut rela Selle TUER rbd 26 23 0 Display UM us enema x gute pad dria creata 27 2 3 Display ANNUNCIATOTS pila 27 Bi Rd E M 27 44 1 Field Units Parameter rire prora 27 4 4 2 Display Contrast casus siot oec rac ae apu ob xdi jun d ORDER MR ic 27 DC and RMS Measurement MOdeS 0 cece cece cence e 27 4 5 1 DC Measurement Mode 0 cece ccc cece cece e es 28 Ae PC MEHR 28 4 5 1 2 DC Operation Zero Probe 0 ccc ccc en 28 4 5 2 AC Measurement Modes siii 29 4 5 2 1 Narrow Band Mode 0 cece cece cece teen eee eee s 30 250292 INSINNA OOS pain ah tacta dp rtm attrahere wine EDUC ar atid 30 4 5 3 Autorange and Range Selection 0 ccc ccc cece cence ence ee 30 4 5 4 Max Hold Function resine are rp 31 4 5 5 Max Reset Function scurrile E Rr ac eU na 31 45 6 Relative MODE iaia M ra eru Noe vun tels 31 Locking and
27. Format Remarks 6 3 1 InterfaceCommands 49 Auto Range Command AUTO off on term n lt off on gt Specifies autorange on or off O Off 1 On AUTO 1 term turns on the autorange feature Auto Range Query AUTO term off on term n refer to command for description Alarm Audible Command BEEP lt off on gt n lt off on gt Specifies alarm audible on or off O Off 1 On This command is included to support compatibility with the Model 455 and Model 475 gaussmeters the alarm audible parameter is now combined with the alarm command term Alarm Audible Query BEEP term off on term n refer to command for description This command is included to support compatibility with the Model 455 and Model 475 gaussmeters the alarm audible parameter is now combined with the alarm command Display Contrast Command BRIGT contrast value gt term nn contrast value 1 to 32 Sets the display contrast for the front panel LCD Display Contrast Query BRIGT term contrast value term nn referto command for description Factory Defaults Command DFLT 99 term Sets all configuration values to factory defaults and resets the instrument the 99 is included to prevent accidentally setting the unit to defaults Keypad Status Query KEYST term keypad status term nn Returns a number descriptor of the last key pressed since the last KEYST KEYST returns a OO if no ke
28. ING RoHS Shock hazard 50 60 Hz COMPLIANT No user servicable parts E Es aaa service personnel Ny USB AUXILIARY 1 0 A PROBE INPUT FIGURE 1 4 Model 425 rear panel showing the line input assembly USB interface auxiliary I O and the probe input 1 5 Hall Probe Full details on Hall probes are provided on our website Please see Selection http www lakeshore com products Hall Probes 1 6 Model 425 Full specifications about the Model 425 gaussmeter are provided on our website Specifications Please see http www lakeshore com products gaussmeters model 425 gaussmeter pages Specifications aspx Model 425 Gaussmeter 1 7 Safety Summary and Symbols 1 7 SafetySummaryand Symbols 5 Observe these general safety precautions during all phases of instrument operation service and repair Failure to comply with these precautions or with specific warn ings elsewhere in this manual violates safety standards of design manufacture and intended instrument use Lake Shore Cryotronics Inc assumes no liability for user failure to comply with these requirements The Model 425 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instru ment Environmental conditions outside of the conditions below may pose a hazard to the operator and surrounding area m Indoor use m Altitude to 2000 m m Temperature for safe operation 5 C to 40 C gm Maximum relativ
29. LSP 1200 term configure the relative setpoint as 1200 G if units in Gauss refer to RELcommand Relative Setpoint Query RELSP term lt setpoint gt term tnnn nnnEtnn refer to command for description Probe Type Query TYPE term lt type gt term nn Returns the probe type 40 high sensitivity 41 high stability 42 ultra high sensitivity 50 user programmable cable high sensitivity probe 51 user programmable cable high stability probe 52 user programmable cable ultra high sensitivitiy probe Field Units Command UNIT lt units gt term n lt units gt 1 Gauss 2 Tesla 3 Oersted 4 Ampere meter UNIT 2 term configures the Model 425 to report readings in Tesla Field Units Query UNIT term units term n refer to command for description u Lake Shore www lakeshore com CRYOTRONICS 54 CHAPTER 6 Computer Interface Operation ZCLEAR Clear Zero Probe Command Input ZCLEAR term Remarks Clears the results of the zero probe function ZPROBE Zero Probe Command Input ZPROBE term Remarks Initiates the Zero Probe function place the probe in zero gauss chamber before issu ing this command Model 425 Gaussmeter 7 1 General 7 2 Models 7 3 Accessories 7 1 General 55 Chapter 7 Probes and Accessories This chapter provides information on standard probes and the accessories available for the Model 425 gaussmeter The list of Model 425 model numbers fol
30. Properties dialog m Click the Hardware tab and then click Device Manager Click View and ensure the Devices by Type checkbox is selected c Inthe main window of Device Manager locate the Ports COM amp LPT device type In many instances this will be between the Network adapt ers and Processors items If the Ports COM amp LPT item is not already expanded click the icon Lake Shore Model 425 should appear indented underneath Ports COM amp LPT If itis not displayed as Lake Shore Model 425 it might be displayed as USB Device If neither are displayed click Action and then select Scan for hardware changes which may open the Found New Hardware wizard automatically If the Found New Hardware wizard opens continue to step 4 d Right click on Lake Shore Model 425 and click Update Driver 4 Select No not at this time and click Next 5 Select Search for the best driver in these locations click to clear the Search removable media floppy CD ROM checkbox and click the Include this loca tion in the search checkbox 6 Click Browse and open the location of the extracted driver Click Next 8 When the driver finishes installing a confirmation message stating The wizard has finished installing the software for Lake Shore Model 425 gaussmeter should appear Click Finish to complete the installation da 6 2 3 4 Installing the USB Driver from the Included CD ROM The Model 425 USB driver is available on the include
31. T CONTINUED Under the terms of this agreement you may only use the Model 425 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 425 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 distin guish 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 LabVIEW is a trademark of National Instruments Microsoft Windows Windows XP and Windows Vista are regis tered trademarks of Microsoft Corporation in the United States and other countries WinZip is a trademark of Nico Mak of Computing Inc Teflon is a registered trademark of E I DuPont de Nemours and Co Manganin is a registered trademark of Isabellenh tte Heuster Gmb H amp Co Copyright 2010 2017 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 reco
32. Unlocking the Keypad 32 Chapter 5 Advanced Operation Chapter 6 Computer Interface Operation Chapter 7 Probes and Accessories 5 1 3 5 3 5 4 5 5 6 1 6 2 6 3 7 1 7 2 7 3 7 4 f 6 2 T 33 The Alarm and Relay FUNCTIONS xsona rr i oh etes 33 5 2 1 Low and High Alarm Setpoints 0c cc cece cence e 33 5 2 2 Magnitude and Algebraic Parameter ccc cece cece ence e 33 5 2 3 Inside and Outside PAFA MELE criniera 34 5 2 4 Alarm Sort Parameter zizi natia 34 5 2 5 Alarm Audible Parameter cece cece cece eee mee 34 NEGRE RT 34 5 2 7 Alarm and Relay Examples spopola 35 5 2 7 1Testing and Sorting of Discrete Magnets ccc cece cence eee 35 5 2 7 2Testing a Magnet Installed inanAssembly ccc cece eee 36 5 2 7 3Monitoring a Static Field uscira dama odo benda Coda Etude ea 36 IAODITOF OHIO ici rum FP aes desde os PSP Ta 37 zueio mucnr p gwE 37 5 4 1 Probe Serial NUMDED 2css0csxaereceuesadusdxsniedsavrdoneoeseaneeeranseveees 38 5 4 2 Field COMPENSAtION 0 cece cece eee Hmmm 38 Edo BXSDSIOH CAD es iocos sided cre se nents cantons qi udo pU Fanb aded s uses 38 5 4 4 Clear Zero Probe Calibration 0 ccc cece cence eee I 38 see RR ei 39 5 5 1 User Programmable Cable ciccia 39 5 5 2 Ohms Measurement MO niat wa db dd irai Yd bantur bad vada 3d tenus 39 GONG idl
33. User s Manual Model 425 Gaussmeter ae 329 MIN m m Y Lake Shore Cryotronics Inc sales lakeshore com 575 McCorkle Blvd service lakeshore com Fax 614 891 1392 Westerville Ohio 43082 8888 USA www lakeshore com 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 2 P N 119 053 25 July 2017 Lake Shore www lakeshore com CRYOTRONICS LIMITED WARRANTY STATEMENT WARRANTY PERIOD THREE 3 YEARS 1 Lake Shore warrants that products manufactured by Lake Shore the Product will be free from defects in materials and workmanship for three years from the date of Purchaser s physical receipt of the Prod uct the Warranty Period If Lake Shore receives notice of any such defects during the Warranty Period and
34. V kG HSE m Between 550 mV kG and 1100 mV kG gamma The Model 425 will adjustthe available ranges based on the values entered for the current and sensitivity Using a sensitivity outside the above ranges may cause reduced performance Values near but lower than the 55 minimum will reduce resolution Values near but above the 11 maximum may cause an instrument overload OL condition before full scale range is reached Therefore using Hall generators with sensitivities outside the above indicated ranges is discouraged All of the above entries will be stored in the HMCBL cable PROM located in the con nector Thus any time you use the cable Hall generator combination the Model 425 will recognize the stored parameters and operation may proceed You can reprogram the HMCBL cables for other Hall generators as needed You can connect a Hall generator directly to the Model 425 without using an HMCBL cable Probe parameters can be configured as stated above but the settings will be lost if power is cycled Menu navigation Probe Setup press and hold for 3 s HMCBL serial number entry nominal sensitivity entry Interface command PRBSENS query only The Model 425 can make a 4 lead resistive measurement If the sensitivity of the probe is set to O the instrument will read in ohms Instrument features are limited in this mode The following ranges are available in this mode 3 5 mO 35 mO 350 mQ and 3 50 mw Lake Shore
35. a cR bone arr P c bacon b aca 10 243 RAGA ON ariete sean 11 Probe CODSIOBI LIONS usus etait d RE n xri T CUR da d Sedul RE ab ach dd ae eaae 12 25 1 OUS iii Lada eU db s Qe canta Us 12 23 E E E E EEE O E EE T E OEE 12 UG O MUTET TT 13 254 eibi M dinak 13 Probe ACCUFACVCONSICETALIONS s crei hard a ob or pde ii 13 26 1 Prope FEMPe dE ll E coniate ia bu ei tuo b ERU odio OR Parto d 13 26 2 Prope CHEN DEDE escriba vicia d dns ODE Sari aede itis UE DRUSI BI d dE 13 20 35 COMO ANON oriana EAE 14 204 OMAX EES eranan eene air lata 14 2 6 5 Induced AC Voltage eririsirercirirerei ead een eS acia eiae bed 14 Cryogenic Measurement Considerations sss 14 2 2L INCA SES cauto rad be ck debui etii aaa deb ss hit pq RED 14 2 2 Temperature Coeficients siriani 14 2 1 3 PIDDSDESIEN pisani 15 alc Een sic RTI ite ie 15 mw Lake Shore www lakeshore com CRYOTRONICS ii TABLE OF CONTENTS Chapter 3 Installation Chapter 4 Operation Model 425 Gaussmeter 3 3 2 3 3 3 4 3 5 3 6 3 7 3 8 4 1 4 2 4 3 4 4 4 5 4 6 Sa FR A E E A E 17 Inspection and Unpacking ssaa nia 17 Rear Panel Definition sae roncsenveuda tances prora nerd 17 Line INpPuUtASSEMDIV e EEE 18 SA LSM E 18 o NI uec P 18 3 4 3 Power Switch RTT m 19 Probe Input COM Me
36. anty Some countries states or provinces do not allow limitations on an implied warranty so the above limita tion or exclusion might not apply to you This warranty gives you spe cific legal rights and you might also have other rights that vary from country to country state to state or province to province 8 Further with regard to the United Nations Convention for Interna tional Sale of Goods CISC if CISG is found to apply in relation to this agreement which is specifically disclaimed by Lake Shore then this limited warranty excludes warranties that a the Product is fit for the purpose for which goods of the same description would ordinarily be used b the Product is fit for any particular purpose expressly or impliedly made known to Lake Shore at the time of the conclusion of the contract c the Product is contained or packaged in a manner usual for such goods or in a manner adequate to preserve and protect such goods where it is shipped by someone other than a carrier hired by Lake Shore 9 Lake Shore disclaims any warranties of technological value or of non infringement with respect to the Product and Lake Shore shall have no duty to defend indemnify or hold harmless you from and against any or all damages or costs incurred by you arising from the infringement of patents or trademarks or violation or copyrights by the Product 10 THIS WARRANTY IS NOT TRANSFERRABLE This warranty is not transferrable 11 Except to the e
37. anywhere in the world No user configuration is required for different voltage operations The Model 425 includes a 3 conductor power cord that mates with the IEC 320 C14 line cord receptacle Line voltage is present on the two outside conductors and the center conductor is a safety ground The safety ground attaches to the instrument chassis and protects the user in case of a component failure A CE approved power cord is included with instruments shipped to Europe a U S power cord is included with all other instruments unless otherwise specified when ordered Always plug the power cord into a properly grounded receptacle to ensure safe operation of the instrument 3 4 3 Power Switch 1 CAUTION 3 5 Probe Input Connection 3 4 3 PowerSwitch 19 The power switch is part of the line input assembly on the rear panel of the Model 425 and it turns line power to the instrument on and off When the circle is depressed power is off When the line is depressed power is on FIGURE 3 2 Position the instrument so that the power switch is easily accessible This section describes the probe input connection and pin out details The Lake Shore Hall probe plugs into the 15 pin D sub socket on the rear panel Align the probe connector with the probe input socket and push straight in to avoid bend ing the pins For best results secure the connector to the rear panel using the two thumbscrews Atight connector keeps the cable secure and preve
38. ar a surface The active area is very close to the stem tip These probes are intended for this specific application and should not be selected for general transverse measurements Flexible and tangential probes are significantly more fragile than other transverse probes m Multiple axis multi axis probes are available for multi axis gaussmeters like the Lake Shore Model 460 These probes are not compatible with the Model 425 Hall effect gaussmeters are equally well suited for measuring either static DC fields or periodic AC fields but proper probe selection is required to achieve optimal performance HST probes are not recommended for use in wide band mode because of their lower sensitivity These probes perform better with the the noise cancellation benefits of the narrow band mode m Metal stem these probe stems are the best choice for DC and low frequency AC measurements Non ferrous metals are used for probe stems because they provide the best protection for the delicate Hall effect sensor without altering the measured field Aluminum is the most common metal stem material but brass can also be used Metal stems do have one drawback eddy currents are generated in them when they are placed in AC fields These eddy currents oppose the field and cause measurement error The error magnitude is proportional to frequency and is most noticeable above 800 Hz m Non metal stem these probe stems are required for higher frequency AC fields an
39. ate sensor with a conductor that provides an output voltage proportional to magnetic flux density As implied by its name this sensor relies on the Hall effect Electrons the majority carrier most often used in practice drift in the conductor when underthe 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 the other side negative This edge charging sets up an electric field which exerts a force on the moving electrons equal and oppo site 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 used in practice by attaching two electrical contacts to each ofthe sides of the con ductor The Hall voltage can be given by the expression Vu ygBsin 0 where V Hall voltage mV yg Magnetic sensitivity mV kG at a fixed current B Magnetic field flux density kG 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 ofthe Hall generator The Hall generator assembly contains the semiconductor material to which the four
40. ated by the user program according to some simple rules to establish effective message flow control 6 2 4 1 Character Format A character is the smallest piece of information that can be transmitted by the inter face Each character is ten bits long and contains data bits bits for character timing and an error detection bit The instrument uses seven bits for data in the American Standard Code for Information Interchange 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 Punctua tion characters are used as delimiters to separate different commands or pieces of data A special ASCII character line feed LF OAH is used to indicate the end of a mes sage string This is called the message terminator 6 2 4 2 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 or query strings can be chained together in one communication but they must be separated by a semicolon The total commu nication string must not exceed 60 characters in length A command string is issued b
41. ccu racy and calibration of this product at the time of shipment are trace able to the United States National Institute of Standards and Technology NIST formerly known as the National Bureau of Stan dards NBS FIRMWARE LIMITATIONS Lake Shore has worked to ensure that the Model 425 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 com puter 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 con clusions 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 conse quential damages Use of 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 copy right law and international treaty provisions To maintain the war ranty 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 FIRMWARE LICENSE AGREEMEN
42. ce the probe tip into the chamber Orientation of the probe is not critical 3 Begin the zeroing process by pressing Zero Probe and then Enter A calibrating message appears on the top line along with a progress bar on the bottom line 4 Press Escape at any time during the zeroing process to cancel the sequence and return to the normal display Previous probe offset values will be retained 5 The process is complete when the instrument returns to normal display Menu navigation Zero Probe Interface command ZPROBE The Model 425 offers two AC measurement bands to improve the overall AC measure ment performance In narrow band mode the instrument uses a 100 mA 5 4 kHz Square wave excitation current This type of excitation provides the benefit of noise cancellation characteristics but it limits maximum frequency to approximately 400 Hz In wide band mode the instrument uses a 100 mA DC excitation current This type of excitation provides the greatest frequency range for RMS measurements up to 10 kHz but this wide bandwidth allows more noise into the measurement It is recommended to use the narrow band mode unless the frequencies of interest are greater than 400 Hz The resolution in AC measurement mode is fixed at 33A digits Menu navigation DC RMS toggle Default DC Interface command RDGMODE To change between the two AC measurement bands follow this menu navigation Menu navigation In AC mode DC RMS press and hold
43. crete Hall generator when a suitable probe is not available You can program nominal sensitivity and serial number into a blank connector HMCBL XX ordered separately to provide all gaussmeter functions except field compensation If the HMCBL cable is not loaded with sensitivity informa tion or a 0 0 sensitivity is mistakenly entered the Model 425 reverts to resistance measurement Unlike a fully calibrated probe the accuracy is affected by the Hall sensor non linearity If you connect an HMCBL cable with no sensitivity information a new blank cable to the Model 425 a message stating invalid probe displays Press Enterto clearthe message Then program the cable with the serial number and nominal sensitivity of the Hall generator If you need to change a previously programmed HMCBL cable connect the HMCBL cable to the instrument If an invalid HMCBL cable is attached for instance a fully calibrated Lake Shore cable and the HMCBL program is attempted a message stat ing Invalid MCBL Cable will appearfor approximately 5 s If this occurs verify that the cable is properly connected If the invalid message continues to appear either replace the cable with a proper HMCBL cable or contact Lake Shore Service Enter the nominal sensitivity in mV kG This sensitivity is based on a 100 mA Hall cur rent Use these ranges to set the nominal sensitivity value m Between 0 550 mV kG and 1 100 mV kG HST m Between 5 500 mV kG and 11 000 m
44. d for measuring pulse fields fiberglass epoxy is a common non metal stem material Alternatively the Hall effect sensor can be left exposed on its ceramic substrate but provides less protection for the sensor Eddy currents do not limit the frequency range of these non conductive materials but other factors may None of these probe types are suitable for direct exposure to high voltage The possibility exists for damage to equipment or injury to the operator if the probe is exposed to high voltage 2 5 3 Gradient 2 5 4 Probe Durability CAUTION 2 6 Probe Accuracy Considerations 2 6 1 Probe Temperature 2 6 2 Probe Orientation 2 5 3 Gradient 13 Probe selection would be easier if all fields were large and uniform but most fields are limited in volume and contain gradients changes in magnitude Hall effect probes measure an average magnitude over their active area making it necessary to under stand the relationship between active area and field gradients Severe field gradients are always experienced as the active sense element is moved away from a permanent magnet pole making it important to know the distance between the active area and probe tip The distance between probe tip and active area is specified for axial probes but is less easily defined for transverse probes m Nominal active area HSE and HST probes have a nominal active area on the order of 1 mm 0 04 in diameter which is useful for all but the most s
45. d CD ROM The following section describes the process of installing the driver from the CD ROM To install the driver you must be logged into a user account that has administrator privileges For Windows Vista Insert the CD ROM into the computer Follow steps 1 to 9 of the Windows Vista procedure in section 6 2 3 3 3 Click Browse and select the drive containing the included CD ROM Ensure the Include subfolders checkbox is selected and click Next When the driver finishes installing a confirmation message stating Windows has successfully updated your driver software should appear Click Close to com plete the installation ae Pe S For Windows XP 1 Insertthe CD ROM into the computer 2 Connect the USB cable from the Model 425 to the computer 3 Turnonthe Model 425 6 2 4 Communication 6 2 4 Communication 45 4 Whenthe Found New Hardware wizard appears select No not at this time and click Next 5 Select Install the software automatically recommended and click Next 6 The Found New Hardware Wizard should automatically search the CD ROM and install the drivers 7 When the Found New Hardware wizard finishes installing the drivers a message stating the wizard has finished installing the software for Lake Shore Model 425 gaussmeter should appear Click Finish to complete the installation Communicating via the USB interface is done using message strings The message strings should be carefully formul
46. ding this bit is set when there is a new field reading 3 8 Alarm this bitis set when there is an alarm condition 4 16 Invalid probe this bit is set when an invalid probe is attached to the instrument 6 6A Calibration error this bit is set if the instrument is not calibrated or the calibration data has been corrupted 7 128 Zero probe done this bit is set when the zero probe function is completed Probe Field Compensation Command PRBFCOMP off on term n off on Specifies probe field compensation off or on valid entries O Off 1 2 On PRBFCOMP 1 term field measurement uses the probe field compensation table PRBFCOMP Input Returned Format PRBSENS Input Returned Format Remarks PRBSNUM Input Returned Format Remarks RANGE Input Format Example RANGE Input Format Returned Format RDGFIELD Input Returned Format Remarks RDGMODE Input Format Example 6 3 1 InterfaceCommands 51 Probe Field Compensation Query PRBFCOMP term off on term n refer to command for description Probe Sensitivity Query PRBSENS term lt sensitivity gt term nnn nnnEtnn Returns the probe sensitivity in mV kG Probe Serial Number Query PRBSNUM term lt type gt term s 8 Returns the probe serial number Field Range Command RANGE lt range gt term n lt range gt Specifies range from lowest to highest 1 to 4 field values are probe dependent RANGE 4 term sets the p
47. ditional conversion factors can be found in the Appendix Flux density is often confused with magnetic field strength Magnetic field strength is a measure of the force producing flux lines The symbol for magnetic field strength is H In the cgs system it is measured in oersteds Oe In the SI system it is measured in amperes per meter A m 1 Oe 79 58 A m Flux density and magnetic field strength are related by the permeability u of the magnetic medium B pH Permeability is a measure of how well a material makes a path for flux lines The confusion of flux density and magnetic field strength is also related to permeabil ity In the cgs system the permeability of air of vacuum is 1 Therefore 1 G 1 Oe or B Hinair Many people incorrectly assume therefore that in the cgs system B Hat all times Adding to the confusion in the SI system permeability of air is not 1 so B is not equal to H even in air 2 4 Hall Measurement Theory F e vxB force on electron 2 4 1 Active Area 2 4 1 ActiveArea 9 The Hall effect is the development of a voltage across a sheet of conductor when cur rentisflowing and the conductor is placed in a magnetic field FIGURE 2 2 The Hall effect was discovered by E H Hall in 1879 and it remained a laboratory curi osity for nearly 70 years Finally development of semiconductors brought Hall gener ators into the realm of the practical A Hall generator is a solid st
48. e IIIa 60 S9 Factory Reset MENU 2 02cuusesrngacsecumsocatbecceetetssnremseabcanbntee ARSS 60 Sb POEN AT 60 8 5 2 Product Information 4u lt a mauarcte ara 61 OO IMO WieSS0C CS A Q 61 8 7 Rear Panel Connector Definitions asducenescarcascaed andra pr 61 8 5 COnDIauoEPFOGSOUG x ss anemone 10 3194 93 00 92 ri bd basse iud uod rd Dd 9d 63 8 9 Firmware Updates e cduaed etr En E 63 8 9 1 Updating the Firmware os oon bad prints vd EXE SR peau hebraice 63 8 9 2 Record of Updates Made to the Firmware cc cece cece e 63 SL TecDICal EO HIIS eoo musco meo ETE veacaes tensa bud dedu md ddd uod dud bate ad wounded 63 9 10 1 Contacting Lake SMOS uacua es count Obs EEUU Ro MEG bte a iro acta 63 8 10 2 Return of EquIDFTiellt sussects rr etrbt Rr a xg xS at 64 8 10 3 RMA Valid PeTIOGQs usd acuaicesduns badare 64 8 104 SMIDDIBE Cal ES cLou sp rOo SIUE osano 64 405 cia did ieri AEREE nni 64 1 1 ProductDescription 1 Chapter 1 Introduction 1 1 Product Description 1 1 1 Throughput Max Alarm Reset Relay M FIGURE 1 1 Model 425 front view Features Field ranges from 350 mG to 350 kG DC measurement resolution to 43 4 digits 1 part of 35 000 Basic DC accuracy of 0 20 DC to 10 kHz AC frequency USB interface Large liquid crystal display Sort function displays pass fail message Alarm with relay Standard probe included Standard and custom
49. e benefits and limitations of the instrument and help apply the features of the Model 425 to a variety of situations It covers flux den sity Hall measurement and probe operation Forinformation on how to install the Model 425 please refer to Chapter 3 Instrument operation information is contained in Chapter 4 and Chapter 5 The Model 425 gaussmeter is a highly configurable device with many built in fea tures It offers a DC mode to measure static or slowly changing fields two different modes to measure AC fields narrow band and wide band and a monitor output Refer to section 2 2 1 and section 2 2 2 for more information on these modes To better illustrate the capabilities ofthe gaussmeter refer to the Model 425 system block dia gram FIGURE 2 1 Product Low pass detector filter Switch FIGURE 2 1 Model 425 system block diagram When in DC mode the instrument uses a 100 mA 5 4 kHz square wave excitation cur rent The voltage that is generated by the Hall sensor goes through an AC coupled pro grammable gain stage From there it passes through the product detector for demodulation a low pass filter and the A D converter The digitized data is then sent to the microprocessor The monitor output will provide a DC voltage proportional to the measured DC field Refer to section 4 5 1 for the procedure to set the DC measure ment mode Refer to section 5 3 for information on monitor output Narrow band mode in this mode the
50. e contributors to the accuracy ofthe reading Both the probe and gaussmeter have accuracy specifications that may impactthe actual reading The probe should be zeroed before making critical measurements The zero probe function is used to null cancel 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 Earth s local magnetic field If you wish to cancel out large magnetic fields use the relative mode section 4 5 6 Probe temperature can also affect readings Referto the two separate temperature coefficients listed in Chapter 1 and section 2 4 2 for an explanation ofthe tempera ture coefficients The HST probes exhibit a low temperature coefficient of gain due to the inherent thermal stability of the materials used in their 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 calibration at Lake Shore The greater the deviation from orthogonality field perpindicular to the plane of the sensor the largerthe error ofthe reading For example a 5 variance on any one axis causes a 0 4 error a 10 misalignment induces a 1 5 error etc FIGURE 3 7 mw Lake Shore www lakeshore com CRYOTRONICS 14 CHAPTER 2 Background 2 6 3
51. e humidity 80 for temperature up to 31 C decreasing linearly to 50 at 40 C m Environments with conducted RF of 1V or EM fields of 1 V m can cause a shift in field readings up to 10 and monitor output up to 5 m Powersupply voltage fluctuations not to exceed 10 of the nominal voltage m Overvoltage category Il m Pollution degree 2 Ground the Instrument To minimize shock hazard the instrument is equipped with a 3 conductor AC power cable Plug the power cable into an approved 3 contact electrical outlet or usea 3 contact adapter with the grounding wire green firmly connected to an electrical ground safety ground at the power outlet The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Ventilation The instrument has ventilation holes in its side covers Do not block these holes when the instrument Is operating Do Not Operate in an Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Opera tion of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away from Live Circuits Operating personnel must not remove instrument covers Refer component replace ment 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
52. e max hold function captures the maximum field reading in magnitude with field polarity sign from the time when the function was turned on or from the last Max Reset press For example if the present maximum reading is 2 kG and the new reading is 3 kG the 3 kG becomes the new maximum reading because field is larger in magnitude and the sign only represents the direction of the field When the max hold function is on the active reading shows on the top line and the maximum read ing shows on the bottom line Menu navigation Max Hold toggle Default off Interface command MXHOLD If the max hold function is on and the Max Reset key is pressed the maximum reading is cleared and reset with the present field reading Menu navigation With max hold function on Max Reset Interface command MXRST The relative mode allows you to take field measurements relative to a measured ref erence field which acts as the relative setpoint The relative reading is equal to the present field value minus the relative setpoint When the relative mode is on the rela tive reading will appear on the top line of the display including the small delta sign signifying the relative display The relative setpoint is shown on the bottom line of the display The relative mode also interacts with other features Relative can be used with max hold to display the maximum relative reading If the alarm function is turned on the instrument uses the relat
53. e service engineer will use the information provided in the service request form and will issue an RMA This number is necessary for all returned equipment It must be clearly indicated on both the shipping carton s and any correspondence relating to the shipment Once the RMA has been approved you will receive appropriate documents and instructions for shipping the equipment to Lake Shore RMAs are valid for 60 days from issuance however we suggest that equipment needing repair be shipped to Lake Shore within 30 days after the RMA has been issued You will be contacted if we do not receive the equipment within 30 days after the RMA is issued The RMA will be cancelled if we do not receive the equipment after 60 days All shipments to Lake Shore are to be made prepaid by the customer Equipment serviced under warranty will be returned prepaid by Lake Shore Equipment serviced out of warranty will be returned FOB Lake Shore Lake Shore reserves the right to charge a restocking fee for items returned for exchange or reimbursement 65 Appendix A Units for Magnetic Properties A 1 Conversion from CGS to SI Units Quantit UI Gaussian Conversion factor SI and rationalized y d and CGS emua Cb mks Magnete fux density B gauss G d 10 4 tesla T Wb m2 magnetic induction E weber Wb cm2 8 Magnetic flux b maxwell Mx G cm 10 volt second V s Magnetic potential dif
54. er location 3 Clickto clear the Show extracted files when complete checkbox and click Extract For Windows XP 1 Right click on the file and click extract all 2 The Extraction wizard will appear Click Next 3 Itis recommended the default folder is not changed Take note of this folder loca tion and click Next 4 An Extraction complete message will be displayed Click to clear the Show extracted files checkbox and click Finish 6 2 3 3 3 Manually install the driver Manually installing drivers differ between versions of Windows The following sections describe how to manually install the driver using Windows Vista and XP To install the driver you must be logged into a user account that has administrator privileges For Windows Vista 1 Connect the USB cable from the Model 425 to the computer 2 Turnon the Model 425 3 Ifthe Found New Hardware wizard appears click Ask me again later 4 Open Device Manager Use this procedure to open Device Manager a Clickthe Windows Start button and type Device Manager in the Start Search box b Click on the Device Manager link in the Search Results Under Programs dialog box c IfUserAccount Control is enabled click Continue on the User Account Control prompt 5 ClickView and ensure the Devices by Type checkbox is selected 6 Inthe main window of Device Manager locate Other Devices in the list of device types In many instances this will be between Network adapte
55. essages remind the operator when a feature is locked out or the instrument is not configured to support a feature Message Defective RAM Description Internal RAM is defective and must be replaced Invalid EEPROM EEPROM contents are corrupt and parameter values will be reset to default Instrument Reoccurrence may indicate defective EEPROM hardware Instrument has not been calibrated or calibration memory has been cor error messages n rupted Recalibration is required for accurate measurements Press the Invalid calibration Escape and Enter keys simultaneously to clear the message The instrument can still be used butit may not be operating within specifications No probe There is no probe attached orthe attached probe is damaged The detected probe does not contain calibration information This is more Invalid probe often the case when using a Hall generator Press Enter to continue and refer to section 5 5 1 to enter probe sensitivity Measurement A previous generation probe has been attached Press Enter to continue Incompatible probe m errror Measurement uses only nominal probe sensitivity Accuracy not guaranteed messages The measured field is larger than the range Increase the measurement range OL orturn autorange on Check probe zero If error condition still exists the probe may be damaged Probe offset larger The amount of adjustment required to set the probe to zero is greater than than expected normal for
56. etime directly related to the number of times they are cycled from room tempera ture to cryogenic temperatures and back The magnitudes of the zero and sensitivity temperature coefficients section 2 4 2 1 and section 2 4 2 2 are amplified substantially by the large temperature changes from room to cryogenic temperatures The approximate magnitude ofthe error can be found in a table with the probe specifications Refer to the magnetics catalog for details Note that this function is not a linear relationship between room tempera ture and 1 5 K 271 65 C If the gaussmeter can be zeroed after the probe reaches the final temperature then the zero temperature coefficient is nullified However if zeroing is not possible at operating temperature then its effect must be considered Especially in low field measurements 100 G 0 01 T the zero offset change must be manually determined and recorded so it can be used for data correction 2 7 3 Probe Design 2 8 Hall Generator CAUTION 2 7 3 Probe Design 15 The HMCA 2560 WN and HMCT 3160 WN probes are long rigid tubes designed mainly for entry into Dewars through o ring fittings This physical configuration may not fit all applications in particular those where the measurement volume is notin direct line with an entry port Contact Lake Shore Applications Engineering to discuss any specific physical requirement Special configurations are available and new probe designs can be quoted I
57. f probes are not suitable for your application cryogenic Hall generators are also available Hall probes may not be suitable in applications with size constraints or in difficult mounting situations In these cases Hall generators may be used Hall generators come in different configurations and sizes Cryogenic Hall generators are also avail able Most Hall generators come with a single point sensitivity calibration that can be entered into the Model 425 referto section 5 5 1 Some Hall generators are avail able with full calibrations butthis data needs to be processed outside the Model 425 it will only use the nominal sensitivity Refer to the Magnetics Catalog on the Lake Shore website for a list of Hall generators that are available Hall generators are very fragile and require delicate handling The ceramic substrate used to produce the Hall sensor is very brittle Use the leads to move the Hall genera tor Do not handle the substrate The strength of the lead to substrate bond is about 198 5 g 7 oz 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 Care must be exercised when handling the Hall generator The device is very fragile Stressing the Hall sensor can alter its output Any excess force can easily break the Hall generator Broken Hall generators are not repairable mw Lake Shore www lakeshore com CRYOTRONICS
58. ffects or the combination of both at specific magnetic field values The Model 425 gaussmeter also has its own temperature coefficients which are typically less than probe coefficients These are listed in on our website http www lakeshore com products gaussmeters model 425 gaussmeter pages Specifications aspx 2 4 2 1 The Temperature Coefficient of Zero The temperature coefficient of zero is a change in the zero field offset with tempera ture This change is always present whether or not a field is measured However the temperature error caused by zero change is often the dominant source of error at magnetic field levels 100 G If you have the ability to zero the gaussmeter at operat ing temperature this coefficient is nullified and has no effect on accuracy If the gaussmeter cannot be zeroed then the zero change effect is present The unit of measure is G C It is generally a fixed number and can be either a positive or negative value This error is specific to each probe and can be a fixed magnitude anywhere from the negative maximum to positive maximum value Model 425 Gaussmeter 2 4 3 Radiation 2 4 3 Radiation 11 Example of zero error assume that the Model 425 is zeroed at 25 C and then the tem perature rises to 50 C AT 25 C Foran HMMT 6J04 VR the worst case zero drift would be 0 09 G C x 25 C 2 25 G maximum This is the maximum temperature error to be expected Most Lake Shore probes exh
59. gap 5 kG 0 5 MRT 062 10K 1 6 mm 0 062 in gap 10 kG 0 5 MRT 343 50 8 7 mm 0 343 in gap 50 G 1 MRT 343 100 8 7mm 0 343 in gap 100 G 1 MRT 343 200 8 7mm 0 343 in gap 200 G 1 MRT 343 1K 8 7 mm 0 343 in gap 1 kG 1 MRT 343 2K 8 7 mm 0 343 in gap 2 kG 1 TABLE 7 5 Probe accessories Lake Shore sells a series of bare Hall generators for applications that are unsuitable for standard probe configurations Refer to the Hall Generator Application Guide for specifications and other details on the various Hall generators Specific instructions for installing Hall generators to the Model 425 are in section 3 8 Please consult Lake Shore for availability of bare Hall generator types not detailed in the Magnetics Catalog www lakeshore com u Lake Shore CRYOTRONICS 58 CHAPTER 7 Probes and Accessories Model 425 Gaussmeter 8 1 General 59 Chapter 8 Service 8 1 General This chapter provides basic service information for the Model 425 gaussmeter Cus tomer service of the product is limited to the information presented in this chapter Lake Shore service personnel should be consulted if the instrument requires repair The purpose of this chapter is to help determine if there is a simple solution to your prob lem or if something is out of working order If you verify that there is something wrong with your instrument do not attempt to open the instrument as there are no serv
60. high low or both alarms For example if you associate the relay with the low alarm the relay will only be activated when the low alarm setpoint is breached If it is set to both the relay will activate if either the high alarm or the low alarm setpoint is breached Menu navigation Alarm Relay gt alarm low alarm setting high alarm setting relay alarm low high both Interface command RELAY Section 5 2 7 1 and section 5 2 7 2 describe some common applications where the alarm function can be used Although the alarm can be used in a variety of applica tions these examples provide an overview of how the alarm features can be used together 5 2 7 1 Testing and Sorting of Discrete Magnets A common application in magnet manufacturing is testing magnets after they have been magnetized In this example the unmagnetized material comes down the assembly line and enters the magnetizer After it is magnetized it continues to a QC area where it is tested for field strength An operator places the magnet into a fixture where the Model 425 is used to measure the flux density The magnet can be placed in the fixture with the north pole facing either up or down In this application the alarm should be setup with the magnitude setting since the orientation is not a factor The inside setting will be used with the audible setting on so that the instrument sounds when the measured field is within tolerance This will give the operator an
61. hin 0 05 kG If the field deviates beyond this amount the Model 425 will alarm indicating that the experimental results are no longer valid The relay will signal external equipment to shut down the experiment In this example the alarm will be setup using the algebraic setting and the outside setting The experiment will be done ata field of 1 kG The low alarm setpoint will be set to 0 95 kG and the high alarm setpoint will be set to 1 05 kG The relay will be setup to follow both alarms If the field remains between the two setpoints the instrument is notin an alarming state and the relay remains deactivated If the field goes higher than 1 05 kG or lower than 0 95 kG then the instrument will alarm and the relay will activate and shut down the experiment 5 3 Monitor Output 5 4 Probe Management 5 3 MonitorOutput 37 The Model 425 provides a monitor output that can be connected to an oscilloscope or data acquisition system The monitor output function provides a voltage proportional to the measured field where 3 5 V equals full scale for the selected range It is cor rected for nominal probe sensitivity and probe offset but it is not corrected for probe non linearities The monitor output function is always enabled To use it connect your measurement device to the monitor output terminals on the rear panel as defined in FIGURE 8 1 The monitor output has two different frequency responses depending on how the instrument is set up
62. ibit lower temperature coefficients 2 4 2 2 The Temperature Coefficient of Sensitivity Calibration The temperature coefficient of sensitivity is related to a change in the magnetic sensi tivity of the Hall device with temperature This change is present only when afield is measured The larger the field the greater the error in G for the same temperature change This characteristic is present in all probes and is specified in units of G C The intrinsic value is always negative for Lake Shore HSE and HST probes meaning that the sensitivity of the Hall sensor decreases with increased temperature Therefore the reading will be lower than the actual magnetic field when the probe is at a tem perature higher than room temperature Lake Shore Hall probes are calibrated at room temperature 25 C when they are used in temperatures other than this tem perature coefficient becomes another source of error Lake Shore HST probes nor mally exhibit a temperature coefficient of sensitivity about ten times better lower than the HSE probes Simply handling the probe at the stem can cause sufficient temperature change of the sensor which can cause the reading to drift handling the probe by the stem is not recom mended as it can break the probe Examples of sensitivity error assume that the Model 425 is zeroed at 25 C and then the temperature rises to 50 C Delta T 25 C Foran HMMT 6J04 VR and Model 425 no compensation measu
63. iceable parts inside contact Lake Shore for service section 8 10 8 2 General Ifthe Model 425 registers a reading that is not appropriate to the situation try the Troubleshooting following solutions m Referto section 8 6 fora list of error messages m Cycle the power m Rezero the probe section 4 5 1 2 m Reset the instrument to factory defaults Section 8 5 m Todetermine whether the issue is with the probe or the instrument test the instrument with a different probe m If none of these solutions work contact Lake Shore section 8 10 8 3 USB This section provides USB interface troubleshooting for issues that arise with new Troubleshooting installations existing installations and intermittent lockups 8 3 1 New Installation 1 Check that the USB driver is installed properly and that the device is functioning Follow this procedure to check the device status m In Microsoft Windows open Device Manager m Locate the Ports COM amp LPT device type In many instances this will be between the Network adapters and Processors items If the Ports COM amp LPT item is not already expanded click the icon m Lake Shore Model 425 should appear indented underneath Ports COM amp LPT or Other Devices Select Lake Shore Model 425 m Click Properties Refer to section 6 2 3 for details on installing the USB driver 2 Check thatthe correct communication port is being used In Microsoft Windows the communication port number can be checked in
64. ing resolution depending on the type of command or query issued TABLE 6 3 Interface commands key Lake Shore www lakeshore com CRYOTRONICS 48 CHAPTER 6 Computer Interface Operation Input Returned Remarks QIDN Input Returned Format Example QRST Input Remarks ALARM Input Format Example ALARM Input Returned Format ALARMST Input Returned Format Model 425 Gaussmeter Process Last Query Received term The response ofthe last query received by the instrument Reprocesses the last query received by the instrument and sends a new response this command cannot be chained with other commands and must be sent by itself Identification Query QIDN term lt manufacturer gt lt model gt lt instrument serial number firmware version term s 4 s 8 s 7 n n manufacturer Manufacturer ID model Instrument model number serial Instrument serial number firmware version Instrument firmware version LSCI MODEL425 4250022 1 0 Reset Instrument Command QRST term Sets controller parameters to power up settings use the DFLT command to set defaults Input Alarm Parameter Command ALARM lt off on gt lt mode gt lt low value gt lt high value gt lt out in gt lt alarm sort gt lt audible gt term n n tnnn nnnEtnn tnnn nnnEtnn n n n lt off on gt Specifies alarm checking on or off O off 1 on lt mode gt Specifies checking magnitude ab
65. interface emulates an RS 232 serial port at a fixed baud rate of 57 600 but with the physical connections of a USB This programming interface requires a cer tain configuration to communicate properly with the Model 425 The proper configu ration parameters are listed in TABLE 6 1 Baud rate 57 600 Data bits 7 Start bits 1 Stop bits 1 Parity Odd Flow control None Handshaking None TABLE 6 1 Host communication port configuration The Model 425 hardware connection uses the USB 2 0 12 000 000 bits s signaling rate however since the interface uses a virtual serial communication port at a fixed data rate the data throughput is still limited to a baud rate of 57 600 mw Lake Shore www lakeshore com CRYOTRONICS 42 CHAPTER 6 Computer Interface Operation 6 2 3 Installing the USB Driver Model 425 Gaussmeter The Model 425 USB driver has been made available through Windows Update This is the recommended method for installing the driver as it will ensure that you always have the latest version of the driver installed If you are unable to install the driver from Windows Update refer to section 6 2 3 3 to install the driver from the Internet or from the CD ROM provided with the Model 425 These procedures assume that you are logged into a user account that has adminis trator privileges 6 2 3 1 Installing the Driver From Windows Update in Windows Vista 1 Connect the USB cable from the Model
66. is unpacked Instruments themselves may be shipped as several parts The items included with the Model 425 are listed below Contact Lake Shore immediately if there is a shortage of parts or accessories Lake Shore is not responsible for any miss ing items if not notified within 60 days of shipment If you need to return the instrument for recalibration replacement or repair a return authorization RMA number must be obtained from a Lake Shore representative Refer to section 8 10 3 for the Lake Shore RMA procedure Probes are shipped in cardboard containers and are often included in the instrument shipping carton Please retain the probe container for probe storage This will help protect the delicate probe from being damaged Items Included with Model 425 gaussmeter BH 1Model425 gaussmeter 1 Model 425 user s manual 11 O mating plug Zero gauss chamber 1 line power cord 1 line power cord for alternative voltage Included only when purchased with VAC 120 ALL power option This section provides a description of the Model 425 rear panel connections The rear panel consists of the probe input socket auxilliary I O socket B type USB connector and the line input assembly FIGURE 3 1 Refer to section 8 7 for rear panel connector pin out details Always turn off the instrument before making the auxiliary I O connection mw Lake Shore www lakeshore com CRYOTRONICS 18 CHAPTER 3 Installation 3 4 Line Input Assembly
67. ive reading to test for alarm conditions mw Lake Shore www lakeshore com CRYOTRONICS 32 CHAPTER 4 Operation 4 6 Locking and Unlocking the Keypad Model 425 Gaussmeter When relative mode is turned on the present reading will be captured and made the new relative setpoint It is also possible to manually set a new relative setpoint through the computer interface Menu navigation Relative toggle Default off Interface command REL RELSP The relative mode is turned off when the instrument is powered off and when chang ing between DC and RMS measurement modes The keypad lock feature prevents accidental changes to parameter settings When the keypad is locked all parameter settings may be viewed but none may be changed from the front panel The Max Reset key remains active even when the keypad is locked When you lock the keypad a message stating Keypad Locked displays for 2 s Changes attempted to any setting result in a brief display of the Keypad Locked message When you unlock the keypad a message stating Keypad Unlocked dis plays for 2 s You are now able to change all Model 425 parameters Menu navigation Enter press and hold for 3 s toggle Default unlocked Interface command LOCK 5 1 General 33 Chapter 5 Advanced Operation 5 1 General 5 2 The Alarm and Relay Functions 5 2 1 Low and High Alarm Setpoints 5 2 2 Magnitude and Algebraic Parameter This chapter pr
68. junction with the magnitude and algebraic parameter Menu navigation Alarm Relay press and hold for 3 s magnitude algebraic inside outside inside out side Default outside Interface command ALARM You can configure the Model 425 alarm to display a pass or fail message when used in repetitive magnet testing situations or sorting operations When the sort parameter is on pass or fail will be displayed on the lower portion of the display When the read ing is in between the high and low alarm setpoints Pass will be shown When the reading is outside of the setpoints Fail High or Fail Low will be shown depending on which setpoint the measured field has crossed The sort message can be turned on or off as necessary and does not affect other operations of the alarm feature The sort parameter is dependent on the magnitude and algebraic parameter butis independent of the inside and outside parameter This means that Pass is always shown between the high and low setpoints Although it is not a typical situation for sorting operations when the inside and out side parameter is set to inside the instrument will show Pass when itis in the alarming state Refer to section 5 2 7 for examples of alarm and relay Menu Navigation Alarm Relay press and hold for 3 s magnitude algebraic inside outside gt audible sort on off Default off Interface command ALARM The Model 425 has an audible alarm annu
69. large magnetic fields use the relative mode section 4 5 6 During the zero probe process do not move the probe until the zero probe process is complete and the display returns to the normal display If during the zero probe pro cess the measured offset is larger than expected the Model 425 will display a mes sage stating The Measured Probe Offset Larger Than Expected The Model 425 will continue to operate with the offset correction but it will be up to the user to investi gate the nature of the offset If through the process of elimination you are not able to discover the reason forthe offset the error message may bean indication of a dam aged probe The Measured Probe Offset Larger Than Expected message can also appear if the probe is exposed to a large magnetic field during the zero probe process If that is the intended operation zero the probe in the zero gauss chamber and then use the relative mode to cancel the large magnetic field 4 5 2 AC Measurement Modes 4 5 2 ACMeasurement Modes 29 For best results allow the instrument and probe to warm up for at least 5 min before zeroing the probe and at least 30 min 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 follow this procedure 1 Allowthe temperature of the probe and chamber to equalize a large tempera ture discrepancy affects the quality of the calibration 2 Carefully pla
70. lows a 425 Model 425 gaussmeter Model 425 gaussmeter with standard probe choice specify selected probe number for HMXX XXXX XX Please see http www lakeshore com products Hall Probes TABLE 7 1 Model description 425 HMXX XXXX XX Power configurations the instrument is configured at the factory for customer selected power as follows 100 V US NEMA 5 15 120 V US NEMA 5 15 220 V EU CEE 7 7 240 V EU CEE 7 7 240 V UK BS 1363 240 V Swiss SEV 1011 220 V China GB 1002 TABLE 7 2 Power configurations NF Ui BP UU MN HB Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit A list of accessories for the Model 425 is as follows G 106 253 I O mating plug G 106 264 I O mating connector shell 4060 Zero gauss chamber MAN 425 Model 425 user manual RoHs compliant TABLE 7 3 Accessories included with Model 425 Description of Accessories 4065 Large zero gauss chamber for gamma probe HMCBL 6 User programmable cable with EEPROM 6 ft HMCBL 20 User programmable cable with EEPROM 20 ft HMPEC 10 U Probe extension cable with EEPROM 10 ft uncalibrated HMPEC 25 U Probe extension cable with EEPROM 25 ft uncalibrated HMPEC 50 U Probe extension cable with EEPROM 50 ft uncalibrated HMPEC 100 U Probe extension cable with EEPROM 100 ft uncalibrated RM 1
71. match a probe with an extension cable 1 Attach the probe and power on the Model 425 2 Pressand hold Probe Setup for approximately 3 s 3 Select HMPEC program and press Enter 4 With the instrument on remove the probe and attach the HMPEC extension cable to the Model 425 Press Enter m ifavalid HMPEC cable is attached a confirmation message stating Copying to Cable will appear while the extension cable is pro grammed with the probe characteristics When the copying process is completed the instrument returns to the normal display m Ifan invalid HMPEC cable is attached and the probe matching process is attempted a message stating invalid HMPEC cable appears for 3 s If this occurs verify that the HMPEC cable is properly connected This message will also appear if an attempt is made to copy to a previously calibrated Lake Shore cable Menu navigation Probe Setup press and hold for 3 s HMPEC In some instances it may be useful to clear the results of the zero probe function This could be of value if the probe was zeroed improperly or if there is reason to believe the probe is damaged By clearing the results of the zero probe function the instrument clears all probe offset values Menu navigation Zero Probe press and hold for 3 s yes no Interface command ZCLEAR 5 5 Hall Generator 5 5 1 User Programmable Cable 5 5 2 Ohms Measurement Mode 5 5 HallGenerator 39 The Model 425 will operate with a dis
72. measurement modes Probe zero allows you to zero all ranges while in DC mode with the simple push of a key Display units field magnitude can be displayed in units of G T Oe and A m with resistance in Q Max hold the instrument stores and displays the captured maximum DC or AC field reading Relative reading the relative mode calculates the difference between a live reading and the relative setpoint to highlight deviation from a known field point This feature can be used in DC or AC measurement modes Instrument calibration Lake Shore recommends an annual recalibration schedule for all precision gaussmeters Recalibrations are always available from Lake Shore butthe Model 425 allows you tofield calibrate the instrument if necessary Recalibra tion requires a computer interface and precision low resistance standards of known value The Model 425 offers the best measurement performance when used along with Lake Shore Hall probes Firmware based features work in tandem with the probe s calibration and programming to ensure accurate repeatable measurements and ease of setup Many ofthe features require probe characteristics that are stored in the probe connector s non volatile memory The Hall effect devices used in gaussmeter probes produce a near linear response in the presence of a magnetic field The small nonlinearities present in each individual device can be measured and subtracted from the field reading Model 425 probes are
73. meter Click Properties 1 Check cable connections and length 2 Increase delay between all commands to 100 ms to make sure instrument is not being overloaded 3 Ensurethatthe USB cable is notunplugged and that the Model 425 is not pow ered down while the com port is open The USB driver creates a com port when the USB connection is detected and removes the com port when the USB connection is no longer detected Removal of the com port while in use by software can cause the software to lock up or crash The Model 425 will operate between the range of 100 VAC to 240 VAC 50 Hz or 60 Hz configurations so that it can be operated from line power anywhere in the world No manual switches need to be configured for different voltage operations It is sometimes necessary to reset instrument parameter values to factory defaults Instrument parameters are stored in nonvolatile memory called EEPROM and can be cleared without affecting instrument calibration The factory defaults can be reset using the factory reset menu To access the factory reset menu press and hold Escape for 3 s The firmware version screen will appear press Enter to advance to the instrument serial number information screen and press Enter to go onto the factory reset menu Once the menu appears set default values to yes then press Enter to confirm and execute the reset Press Escape at any time to return to the normal display Default parameter values are listed in TABLE
74. must be observed Probes used with the gaussmeter have conductive parts Never probe near exposed live voltage Personal injury and damage to the instrument may result Although every attempt has been made to make the probes as sturdy as possible they are still fragile This is especially true for the exposed sensor tip of some transverse probes While taking measurements be careful not to place pressure on the probe tip 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 Hall 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 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 object Although damaged or severed cables should be returned to Lake Shore for repair understand that probes are not always repairable When probes are installed on the gaussmeter but are 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 The cardboard and foam container that Lake Shore probes are shipped in should be retained for probe storage when the gaussmeter is notin use For further details on available accessories and probes refer to Chapter 7
75. n 4 2 2 General Keypad Operation 4 3 Display Definition Model 425 Gaussmeter The Model 425 uses three basic keypad operations for the majority of operator inter face direct operation press and hold and setting selection Direct operation the key feature occurs immediately when the key is pressed DC RMS Max Hold and Relative are examples of keys that operate this way Press and hold the key feature occurs when the key is pressed and held for approx imately 3 s Itis used to modify less frequently changed features This operation is described in the individual sections for keys with secondary functions available Setting selection allows you to select from a finite list of values During setting selection the s and t keys are used to select a value Enter is used to accept the change and advance to the next setting Escape will cancel the change to that setting and return to the normal display Setting selection screens always include the message Select with st Numeric data entry allows you to enter numeric data using the s and t keys Low and high alarm setpoints are examples of parameters that require numeric data entry Presssortto cycle through the available ranges the sign and the numerals 0 through 9 depending on what is being entered Press Enter to advance the cursor to the next position orto save the number and return from numeric data entry mode if it is in the last position Press Escape to restart the number en
76. n or site maintenance g natural disasters such as flood fire wind or earthquake or h damage during ship ment other than original shipmentto you if shipped through a Lake Shore carrier 6 This limited warranty does not cover a regularly scheduled or ordi nary and expected recalibrations of the Product b accessories to the Product such as probe tips and cables holders wire grease varnish feed throughs etc c consumables used in conjunction with the Product such as probe tips and cables probe holders sample tails rods and holders ceramic putty for mounting samples Hall sample cards Hall sample enclosures etc or d non Lake Shore branded Products that are integrated with the Product 7 To the extent allowed by applicable law this limited warranty is the only warranty applicable to the Product and replaces all other war ranties or conditions express or implied including but not limited to the implied warranties or conditions of merchantability and fitness for a particular purpose Specifically except as provided herein Model 425 Gaussmeter Lake Shore undertakes no responsibility that the products will be fit for any particular purpose for which you may be buying the Products Any implied warranty is limited in duration to the warranty period No oral or written information or advice given by the Company its Agents or Employees shall create a warranty or in any way increase the scope ofthis limited warr
77. nciator or beeper The beeper will sound when the instrument is in an alarming state If the beeper is not appropriate for your application you can turn it off Menu navigation Alarm Relay press and hold for 3 s magnitude algebraic inside outside audible on off Default on Interface command ALARM The Model 425 has one mechanical relay that you can connect to external control equipment It is most commonly associated with the high and low alarms but it can be controlled manually and used for other purposes When the instrument is powered off the relay defaults to its normal state The relay is rated for 30 VDC and 2 A and its terminals are located in the auxiliary I O socket on the Model 425 rear panel Refer to section 8 7 for rear panel connector definitions 5 2 7 Alarm and Relay Examples 5 2 7 Alarmand Relay Examples 35 The relay has two modes of operation m Manual allows you to turn the relay off normal or on active manually from the front panel or over the computer interface m Alarm the relay follows the operation of the alarms You can tie the action of the relay to the high alarm low alarm or both alarms The relay is activated any time the associated alarm is in an alarming state Menu navigation Alarm Relay gt alarm gt low alarm setting gt high alarm setting relay on off alarm Default off Interface command RELAY If the relay is in alarm mode you can associate the relay with the
78. nge on or off Definition of first parameter 0 Off 1 On some commands have multiple parameters Example AUTO 1 term turns on the autorange feature FIGURE 6 1 Sample command format Query name Brief description of query Form of the query input Auto Range Query AUTO term Definition of returned parameter Returned lt off on gt term Format n refer to command for description Syntax of returned parameter FIGURE 6 2 Sample query format Model 425 Gaussmeter 6 3 1 InterfaceCommands 47 Command Function Page Command Function Page Process Last Query Received 48 PRBSENS Probe Sensitivity Query 51 IDN Identification Query 48 PRBSNUM ProbeSerial Number Query 51 RST Reset Instrument Command 48 RANGE Field Range Command 51 ALARM Input Alarm Parameter Command 48 RANGE Field Range Query 51 ALARM Input Alarm Parameter Query 48 RDGFIELD Field Reading Query 5 ALARMST AlarmStatus Query 48 RDGMODE Measurement Mode Command 51 AUTO Auto Range Command 49 RDGMODE Measurement Mode Query 52 AUTO Auto Range Query 49 RDGMNMX Minimum and Maximum Reading Query 52 BRIGT Display Contras Command 49 RDGMX Maximum Reading Query 52 BEEP Alarm Audible Command 49 RDGREL Relative Reading Query 52 BEEP Alarm Audible Query 49 REL Relative Mode Command 52 BRIGT Display Contrast Query 49 REL Relative Mode Query 52 DFLT Factory Defaults Command 49 RELAY Relay C
79. nput socket LINECCCNNLINNC CNN 1 Vinput V input 2 No connection 10 No connection 3 Internal use only 11 EEPROM GND 4 Internal use only 12 EEPROM VCC 5 Internal use only 13 EEPROM CLK 6 Internal use only 14 EEPROM DATA 7 No connection 15 Hall 8 Hall TABLE 8 4 Probe input connector details 2 1 Ll 3 4 FIGURE 8 3 USB connector ERI 1 VCC 5 VDC 2 D Data 3 D Data 4 GND Ground TABLE 8 5 USB connector details Model 425 Gaussmeter 8 8 Calibration Procedure 8 9 Firmware Updates 8 9 1 Updating the Firmware 8 9 2 Record of Updates Made to the Firmware 8 10 Technical Inquiries 8 10 1 Contacting Lake Shore 8 8 Calibration Procedure 63 Instrument calibration can be obtained through Lake Shore Service Refer to section 8 10 for technical inquiries and contact information This section provides instructions on updating your firmware It also provides a table of the updates that have been made thus far Periodically Lake Shore provides updates to instrument firmware The files for these updates can be downloaded from our website To access the firmware updates follow this procedure 1 Goto http www lakeshore com products gaussmeters Mode 425 Gaussme ter pages overview aspx to download the instrument and Ethernet firmware 2 Enter yourname and email address so that we can keep you updated on any new firmware for your instrument
80. nt Service Department Maring andres 575 McCorkle Blvd Westerville Ohio USA 43082 8888 sales lakeshore com Sales Emel agence service lakeshore com Product Service EUR 614 891 2244 Sales P 614 891 2243 option 4 Product Service Far 614 818 1600 Sales 614 818 1609 Product Service Web service request http www lakeshore com sup serf html Product Service TABLE 8 7 Contact information u Lake Shore www lakeshore com CRYOTRONICS 64 CHAPTER 8 Service 8 10 2 Return of Equipment 8 10 3 RMA Valid Period 8 10 4 Shipping Charges 8 10 5 Restocking Fee Model 425 Gaussmeter The gaussmeter is packaged to protect it during shipment The user should retain any shipping carton s in which equipment is originally received in the event that any equipment needs to be returned If original packaging is not available a minimum of 76 2 mm 3 in of shock absorbent packing material should be placed snugly on all sides ofthe instrument in a sturdy corrugated cardboard box Please use reasonable care when removing the gaussmeter from its protective packaging and inspect it carefully for damage If it shows any sign of damage please file a claim with the carrier immediately Do not destroy the shipping container it will be required by the carrier as evidence to support claims Call Lake Shore for return and repair instructions All equipment returns must be approved by a member of the Lake Shore Service Department Th
81. nt unintended changes of instrument setup High and low alarm functions and one relay are included with the instrument and can be used to automate repetitive magnet testing and sorting operations Alarm actuators include display annunciator audible beeper and a relay The alarm can be configured to display a pass or fail message and the relay can be configured to acti vate a mechanism to separate parts that meet pre set fail criteria The relay can also be controlled manually for other system needs The monitor output provides an analog representation ofthe reading that is cor rected for probe offset and nominal sensitivity This feature makes it possible to view the analog signal which has not been digitally processed The monitor output can be connected to an oscilloscope or data acquisition system mw Lake Shore www lakeshore com CRYOTRONICS 4 CHAPTER 1 Introduction 1 4 4 Computer The Model 425 is equipped with a universal serial bus USB interface It emulates an Interface RS 232C serial port at a fixed baud rate of 57 600 but with the physical connections of a USB In addition to gathering data nearly every function of the instrumentcan be controlled through the USB interface The reading rate over the interface is nominally 30 readings per second A LabVIEW driver is available from the download section of the Lake Shore website at www lakeshore com 1 4 5 Model 425 Rear Panel E Z WARN
82. nto an optional HMCBL blank connector to provide all gaussmeter functions except field compensation If no sensitivity information is available the Model 425 reverts to resistance measurement The Model 425 has a 2 line by 20 character liquid crystal display During normal operation the display is used to report field readings and give results of other fea tures such as max or relative When setting the instrument parameters the display gives you meaningful prompts and feedback to simplify operation Following are four examples of the various display configurations FIGURE 1 2 Left Normal reading the default mode with the display of the live DC field reading Right Max DC hold on the maximum value is shown in the lower display while the upper display contains the live DC field reading FIGURE 1 3 Left Alarm on the alarm gives an audible and visual indication of when the field value is selectively outside or inside a user specified range The relay can be associated with the alarm Right Sort on the live reading is shown in the upper display while the lower display contains the pass fail repetitive sorting or testing message The relay facilitates pass fail operation 1 4 1 Keypad 1 4 2 Alarm Relay and Sort 1 4 3 Monitor Output The instrument keypad has 14 keys with individual keys assigned to frequently used features Menus are reserved for less frequently used setup operations The keypad can be locked out to preve
83. nts interference Refer to section 3 6 for additional probe considerations An 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 field compensa tion data and calibration data When a new probe is connected the instrument reads parameters from probe memory and the probe is ready to use A new probe can be connected atany time even while the instrument is turned on No parameters need to be entered into the Model 425 for a Lake Shore probe However the zero probe func tion should be performed the first time a probe is used with the instrument and peri odically during use section 4 5 1 2 PROBE INPU FIGURE 3 3 Probe input socket out ron 1 V input 9 V input 2 Internal use only 10 No connection 3 Internal use only 11 EEPROM GND 4 Internal use only 12 EEPROM VCC 5 Internal use only 13 EEPROM CLK 6 Internal use only 14 EEPROM DATA 7 No connection 15 Hall I Hall TABLE 3 2 Probe input connector details mw Lake Shore www lakeshore com CRYOTRONICS 20 CHAPTER 3 Installation 3 6 Probe Handling and Operation AWARNING 3 6 1 Probe Handling 1 CAUTION 3 6 2 Probe Mounting Model 425 Gaussmeter To avoid damage and for best results during use probes have a number of handling and accuracy requirements that
84. obeAccessories able for the 425 gaussmeter is provided in TABLE 7 5 Refer to the Lake Shore Magnetics Catalog for more details Description of accessories 3 Probe extension cables HMPEC 10 m 10 ft HMPEC 10 U m 10 ft HMPEC 25 m 25 ft HMPEC 25 U 8m 25 ft HMPEC 50 15 m 50 ft HMPEC 50 U 15m 50ft HMPEC 100 30m 100ft HMPEC 100 U 30m 100 ft Hall generator cable assemblies HMCBL 6 2 m 6 ft HMCBL 20 6 m 20 ft Helmholtz coils 63 5 mm 2 5 in inner diameter field strength 30 G at 1 A ii maximum continuous current 2 A coil resistance 3 Q MH 6 152 4 mm 6 in inner diameter field strength 25GatlA maximum continuous current 2 A coil resistance 10 O MH 12 304 8 mm 12 in inner diameter field strength 13GatlA maximum continuous current 2 A coil resistance 20 O Axial reference MRA 312 100 7 9mm 0 312 in inside diameter 100 G 1 magnets MRA 312 200 7 9 mm 0 312 in inside diameter 200 G 1 MRA 312 300 7 9mm 0 312 in inside diameter 300 G 1 MRA 312 500 7 9mm 0 312 in inside diameter 500 G 1 MRA 312 1K 7 9 mm 0 312 in inside diameter 1 kG 1 MRA 312 2K 7 9 mm 0 312 in inside diameter 2 kG 1 Transverse reference MRT 062 200 1 6mm 0 062 in gap 200 G 1 magnets MRT 062 500 1 6 mm 0 062 in gap 500 G 1 MRT 062 1K 1 6 mm 0 062 in gap 1 kG 0 596 MRT 062 2K 1 6 mm 0 062 in gap 2 kG 0 596 MRT 062 5K 1 6 mm 0 062 in
85. ommunication determine which device should be transmitting at a given time or guarantee timing between mes sages All of this is the responsibility of the user program When issuing commands the user program alone should m Properly format and transmit the command including the terminator as one string m Guarantee that no other communication is started for 30 ms after the last char acter is transmitted m Notinitiate communication more than 30 times s When issuing queries or queries and commands together the user program should m Properly format and transmit the query including the terminator as one string m Prepare to receive a response immediately m Receive the entire response from the instrument including the terminator m Guarantee that no other communication is started during the response or for 30 ms after it completes m Not initiate communication more than 30 times s Failure to follow these rules will result in inability to establish communication with the instrument or intermittent failures in communication 6 3 Command This section provides a listing of the interface commands Asummary of all the com Summary mands is provided in TABLE 6 2 All the commands are detailed in section 6 3 1 and are presented in alphabetical order Command name Brief description of command Form of the command input Auto Range Command AUTO off on term n Syntax of user parameter input see key below off on Specifies autora
86. ontrol Parameter Command 52 KEYST Keypad Status Query 49 RELAY Relay Control Parameter Query 53 LOCK Front Panel Keypad Lock Command 50 RELAYST Relay Status Query 53 LOCK Front Panel Keypad Lock Query 50 RELSP Relative Setpoint Command 53 MXHOLD Max Hold Command 50 RELSP Relative Setpoint Query 53 MXHOLD Max Hold Query 50 TYPE Probe Type Query 53 MXRST Max Hold Reset Command 50 UNIT Field Units Command 53 OPST Operational Status Query 50 UNIT Field Units Query 53 PRBFCOMP Probe Field Compensation Command 50 ZCLEAR Clear Zero Probe Command 54 PRBFCOMP Probe Field Compensation Query 51 ZPROBE Zero Probe Command 54 These commands were included to support compatibility with the Model 455 and Model 475 gaussmeters 6 3 1 Interface Commands Q TABLE 6 2 Command summary Begins common interface command This section lists the interface commands in alphabetical order s n Required to identify queries String of alphanumeric characters with length n Send these strings using surrounding quotes Quotes enable characters such as commas and spaces to be used without the instrument interpreting them as delimiters String of number characters that may include a decimal point term Terminator characters lt gt lt state gt Indicates a parameter field many are command specific Parameter field with only On Off or Enable Disable states lt value gt Floating point values have vary
87. oose between testing for magnitude only magnitude setting or for both magnitude and field polarity alge braic setting With the magnitude setting the instrument ignores the field polarity or sign and instead only tests the magnitude of the field This setting is used when orientation of the magnet is nota factor for determining whether a magnet passes or fails a magnet test With the algebraic setting the instrument measures the magnitude of the field as well as field polarity For instance you could use the algebraic setting if you test mag nets that are part of an assembly where both the orientation and magnitude are important Menu navigation Alarm Relay press and hold for 3 s gt magnitude algebraic Default magnitude Interface command ALARM mw Lake Shore www lakeshore com CRYOTRONICS 34 CHAPTER 5 Advanced Operation 5 2 3 Inside and Outside Parameter 5 2 4 Alarm Sort Parameter 5 2 5 Alarm Audible Parameter 5 2 6 Relay Model 425 Gaussmeter The inside and outside parameter allows you to choose whether the alarm activates when the field reading is either inside or outside the user specified setpoints Choos ing the inside setting means the alarm will activate when the reading is inside the range of the high and low setpoints Choosing the outside setting means the alarm will activate when the reading is outside the range of the high and low setpoints The inside and outside parameter works in con
88. ovides information on advanced operations for the Model 425 gaussmeter The alarm function is commonly used to automate magnet testing and sorting in a factory environment To configure the alarm choose between the magnitude or alge braic setting section 5 2 2 then choose between an inside or outside setting section 5 2 3 To complete the alarm setup enter your high and low alarm setpoints In addition to these steps you can configure the alarm to work in a way that best suits your working conditions For instance while the instrument will automatically dis play an annunciator when the alarm function is turned on you can also choose to display a pass fail message section 5 2 4 Finally the alarm can be configured to work in conjunction with the relay section 5 2 6 which can be connected to external control equipment Menu navigation Alarm Relay off on Default off Interface command ALARM The alarm must be turned on in order to set the high and low alarm setpoints from the front panel When entered the high and low alarm setpoint values will match the field units in which the instrument is set The range of values that can be entered are limited to 350 kG independent of the probe that is attached Refer to section 4 2 2 for numeric entry Menu navigation Alarm Relay gt on gt low alarm setpoint high alarm setpoint Default O Interface command ALARM The magnitude and algebraic parameter allows you to ch
89. probe and the magnet being measured should be at the same temperature Simply handling the magnet can cause sufficient temperature change to cause the reading to drift mw Lake Shore www lakeshore com CRYOTRONICS 22 CHAPTER 3 Installation If the exact orientation of the magnetic field is unknown the proper magnitude is determined by turning on max hold and slowly rotating 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 orienta tion 29 396 B 13 4 in O 6 0 i 3 4 20 E 15 0 4 po 096 0 Error Deviation from perpendicular a Effect of angular variations on percentage of reading error where percent error 1 cos a 100 FIGURE 3 7 Effect of angle on measurements 3 7 Auxiliary 1 0 The auxiliary I O connector is a 25 pin D sub socket This provides access to the mon Connection itor output and relays The mating plug and connector shell are included with the Model 425 The pins are defined in TABLE 3 3 AUXILIARY I O UTI ny n RO RA M be E45 LA S NI jJ ai sli E ebria limi 4 i FIGURE 3 8 Auxiliary I O socket out ron 1 Monitor out 14 Ground 2 Internal use only 15 Ground 3 Internal use only 16 Ground 4 No connection 17 No connection 5 Internal use only 18 No connection 6 Internal use only 19 No connection 7 No connection 20
90. probes available Designed to meet the demanding needs of the permanent magnet industry the Lake Shore Model 425 gaussmeter provides high end functionality and performance in an affordable desktop instrument Magnet testing and sorting have never been easier When used in combination with the built in relay and audible alarm features the Model 425 takes the guesswork out of pass fail criteria Additional features including DC to 10 kHz AC frequency response max hold and relative measurement make the Model 425 the ideal tool for your manufacturing quality control and R amp D flux density measurement applications For added functionality and value the Model 425 also includes a standard Lake Shore Hall probe Put the Model 425 gauss meter to use with confidence knowing it s supported by the industry leading experts in magnet measurement instrument sensor and Hall probe technology Throughput involves much more than just the update rate of an instrument An intui tive menu navigation and keypad along with overall ease of use are equally import ant The Model 425 is designed with these qualities in mind The operation is straightforward with user display prompts to aid set up We understand that time is money In addition to being user friendly the automated magnet testing and sorting features ofthe Model 425 streamline sorting and testing operations In addition hot swapping of Hall probes allows you to switch probe types without powering the in
91. r we recommend that the customer always check accuracy against a reference field to verify the sensitivity value sent with the bare Hall generator Lake Shore has no control of the installation therefore the user must accept respon sibility for accuracy and compatibility In cryogenic applications Manganin lead wire is frequently used because of its thermal conductivity properties Manganin wire is not usually acceptable for con nection to a Hall generator because the resistance of Manganin wire is often too high The gaussmeter current source is limited in compliance voltage The Model 425 should not drive a load Hall sensor customer leads and cable greater than 30 O In cryogenic applications Hall generators are normally connected using twisted pairs of copper wire such as 34 AWG Teflon insulated wire The HMCBL XX cable has a 15 pin D sub plug on one end for direct attachment to the probe input socket on the rear panel of the Model 425 gaussmeter The four leads illustrated in FIGURE 3 9 correspond to the four leads on the Hall generators The leads may be soldered directly to these wires Once connections are made refer to section 5 5 1 for instructions on programming parameters into the internal EEPROM Currentto J Green wire Ic Sensor Red wire lc Hall voltage Blue wire V from sensor Yellow wire Vy FIGURE 3 9 Model HMCBL XX user programmable cable accessory Accidental contact of Hall generator
92. ration Model 425 Gaussmeter You can view the serial number of the attached probe from the display of the Model 425 This feature can be used to check the programming of extension cables To view the serial number press Probe Setup The probe serial number screen will appear for approximately 3 s The serial number is up to 10 digits in length Menu navigation Probe Setup probe serial number screen appears for 3 s Interface command PRBSNUM To improve accuracy all Lake Shore probes have a magnetic field compensation table stored in their EEPROM Turning field compensation off causes the Model 425 to ignore this table and calculate the field based on a nominal probe sensitivity Unless there is a specific reason Lake Shore strongly advises users not to turn field com pensation off it may reduce reading accuracy substantially Menu navigation Probe Setup probe serial number appears for 3 s off on Default on Interface command PRBFCOMP Hall effect measurements make it necessary to match extension cables to probes when longer cables are needed When using an extension cable the calibration in the probe needs to be copied to the extension cable Stored information can be viewed on the front panel and read over computer interface to ensure proper mating In most cases you can use uncalibrated extension cables the probe calibration can be transferred to the extension cable using the Model 425 Follow this procedure to
93. rding or otherwise without the express written permission of Lake Shore u Lake Shore EL ce s www lakeshore com u Lake Shore CRYOTRONICS EU DECLARATION OF CONFORMITY CE This declaration of conformity is issued under the sole responsibility of the manufacturer Manufacturer Lake Shore Cryotronics Inc 575 McCorkle Boulevard Westerville OH 43082 USA Object of the declaration Model s 425 Description Gaussmeter The object of the declaration described above is in conformity with the relevant Union harmonization legislation 2014 35 EU Low Voltage Directive 2014 30 EU EMC Directive 2011 65 EU RoHS Directive References to the relevant harmonized standards used to the specification in relation to which conformity is declared EN 61010 1 2010 Overvoltage Category Il Pollution Degree 2 EN 61326 1 2013 Class A Controlled Electromagnetic Environment EN 50581 2012 Signed for and on behalf of Place Date Westerville OH USA Scott Ayer 21 JUL 2017 Director of Quality amp Compliance Model 425 Gaussmeter Chapter 1 Introduction Chapter 2 Background 1 1 1 2 1 3 1 4 1 5 1 6 1 7 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 Table of Contents Product Descrip UON aan sad us asd hid rare ea ere 1 LIO oor E E tation causa EE it T 1 11 2 DCMeasurement Mode paesi eine 2 1 1 3 AC Measurement Mode ae armies caren ra P PRU E adr dd a bR a 2 Measurement Featul6S
94. recommended when measuring AC fields with a large DC background field Autorange and manual range selection are available by pressing Range Menu navigation Range Range refer to TABLE 4 4 Default range 4 highest Interface command RANGE AUTO 4 5 4 MaxHoldFunction 31 The ranges that are available depend on the probe type high stability high sensitiv ity and ultra high sensitivity TABLE 4 4 lists full scale ranges for each probe sensitiv ity along with the maximum number of digits of display resolution Measurement resolution noise floor varies depending on probe and application OE Oersted Ampere meter 350 00 kG 35 000 T 350 00 kOe 28 000 MA m A 35 000 kG 3 5000 T 35 000 kOe 2 8000 MA m High stability probe HST 3 5000 kG 350 00 mT 3 5000 kOe 280 00 kA m 350 00G 35 000 mT 350 00 Oe 28 000 kA m 35 000 kG 3 5000T 35 000 kOe 2 8000 MA m A va 3 5000 KG 350 00 mT 3 5000 kOe 280 00 kA m High sensitivity probe HSE 350 00 G 35 000 mT 350 00 Oe 28 000 kA m 35 000G 3 5000 mT 35 000 Oe 2 8000 kA m een 35 000G 3 5000 mT 35 000 Oe 2 8000 kA m a ele ME ERE 3 5000 G 350 00 pT 3 5000 Oe 280 00 A m 350 00 mG 35 000 uT 350 00 mOe 28 000 A m Accuracy for this range is not guaranteed for all HST probes 4 5 4 Max Hold Function 4 5 5 Max Reset Function 4 5 6 Relative Mode TABLE 4 4 Range and resolution for each probe type Th
95. resent range to 4 Field Range Query RANGE term n range term n refer to command for description Field Reading Query RDGFIELD term field term nnn nnnEtnn Returns the field reading in a format based on the present units this is valid for DC or RMS Measurement Mode Command RDGMODE lt mode gt lt filter gt lt band gt term n n n mode Specifies the measurement mode 1 DC 2 RMS filter Turns DC filter on or off O Off 1 On band RMS measurement mode 1 wide band 2 narrow band RDGMODE 2 1 1 term the Model 425 is configured for RMS field measurement in wide band mode u Lake Shore www lakeshore com CRYOTRONICS 52 CHAPTER 6 Computer Interface Operation RDGMODE Input Returned Format RDGMNMX Input Returned Format Remarks RDGMX Input Returned Format Remarks RDGREL Input Returned Format Remarks REL Input Format Example REL Input Returned Format RELAY Input Format Example Model 425 Gaussmeter Measurement Mode Query RDGMODE term lt mode gt lt filter gt lt band gt term n n n refer to command for description Maximum and Minimum Reading Query RDGMNMX term min maxo term tnnn nnnEtnn tnnn nnnEtnn This command is included to support compatibility with the Model 455 and Model 475 gaussmeters in the Model 425 this query will always return zero forthe mini mum value Maximum Reading Que
96. rface command UNIT The front panel LCD display contrast can be adjusted for optimal viewing The default should work well in most standard room temperature environments but deviations from room temperature and extreme viewing angles can cause the display contrast to require adjustment for optimal viewing Menu navigation Interface press and hold for 3 s gt Contrast 1 to 32 Default 10 Interface command BRIGT The Model 425 can be configured for DC or RMS measurements Pressing DC RMS toggles between DC and RMS measurement modes The DC RMS annuncia tor on the display will immediately change to DC or RMS depending on what mea surement mode has been selected mw Lake Shore www lakeshore com CRYOTRONICS 28 CHAPTER 4 Operation 4 5 1 DC Measurement Mode Model 425 Gaussmeter To measure static or slowly changing fields use the DC measurement mode In DC measurement mode the display shows the measured DC field and the polarity sign followed by the appropriate field units The resolution of DC readings is 33 4 digits when the filter function is turned off and 43 4 digits when the filter is turned on section 4 5 1 1 The monitor output will provide a DC voltage proportional to the measured DC field where 3 5 V equals full scale for the selected range Menu navigation DC RMS toggle Default DC Interface command RDGMODE 4 5 1 1 Filter The filter is a moving average filter of 16 readings and settles
97. ring a 1 000 KG field the worst case sensitivity change would be 0 04 C x 25 C 1 maximum 1 of 1 000 kG 10G reads low 10 G Also note that if the probe were a Model HMMT 6J04 VF the worst case sensitivity change would be 0 005 C x 25 C 0 125 maximum 0 125 of 1 000 kG 1 25 G reads low 1 25 C This is the maximum temperature error to be expected Most Lake Shore probes exhibit lower temperature coefficients The HST and HSE probes use a highly doped indium arsenide conductor 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 provided in the following list The changes in sensitivity are the maxi mums expected if the sensor is exposed atthe given rates indefinitely m Gammaradiation seems to have little effect on the Hall generators m Proton radiation up to 10 Mrad causes sensitivity changes less than 0 5 m Neutron cumulative radiation gt 0 1 MeV 1015 cm2 can cause a 3 to 596 decrease in sensitivity In all cases the radiation effects on the Hall sensors seem to saturate and diminish with cumulative exposure the length of time for these effects to diminish varies depending upon radiation intensity mw Lake Shore www lakeshore com CRYOTRONICS 12 CHAPTER 2 Background 2 5 Probe Considerations 2 5 1 Orientation 2 5 2 Frequency AWARNING Model
98. rs and Ports COM amp LPT Ifthe Other Devices item is not already expanded click the icon Lake Shore Model 425 should appear indented underneath Other Devices If it is not displayed as Lake Shore Model 425 it might be displayed as USB Device If neither are displayed click Action and then Scan for hardware changes which may open the Found New Hardware wizard automatically If the Found New Hardware wizard opens click Cancel 7 Right click on Lake Shore Model 425 and click Update Driver Software 8 Click Browse my computer for driver software mw Lake Shore www lakeshore com CRYOTRONICS ad CHAPTER 6 Computer Interface Operation Model 425 Gaussmeter 9 Click Browse and select the location of the extracted driver 10 Ensure the Include subfolders check box is selected and click Next 11 When the driver finishes installing a confirmation message stating Windows has successfully updated your driver software should appear Click Close to com plete the installation For Windows XP 1 Connect the USB cable from the Model 425 to the computer 2 Turnonthe Model 425 3 The Found New Hardware wizard should appear If the Found New Hardware wizard does not appear the following procedure can be used to open the Hard ware Update wizard which can be used instead a Open Device Manager Use this procedure to open Device Manager m Right clickon My Computer and then click Properties This will open the System
99. ry RDGMX term max term nnn nnnEtnn Returns the most recent maximum field reading Relative Reading Query RDGREL term lt relative reading gt term nnn nnnEtnn Returns the relative field reading Relative Mode Command REL off on term n lt off on gt Specifies Relative mode off or on O Off 1 On REL 1 term relative mode turned on Relative Mode Query REL term lt off on gt term n refer to command for description Relay Control Parameter Command RELAY lt mode gt lt alarm type term n n lt mode gt lt alarm type gt Specifies relay mode 0 Off 1 On 2 Alarm Specifies the input alarm type that activates the relay when the relay is in alarm mode 1 Low alarm 2 High Alarm 3 Both Alarms RELAY 2 1 term relay activates when low alarm activates RELAY Input Returned Format RELAYST Input Returned Format RELSP Input Format Example RELSP Input Returned Format TYPE Input Returned Format Remarks UNIT Input Format Example UNIT Input Returned Format 6 3 1 InterfaceCommands 53 Relay Control Parameter Query RELAY term mode alarm type term n n refer to command for description Relay Status Query RELAYST term status term n 0 20ff 1 0n Relative Setpoint Command RELSP lt setpoint gt term nnn nnnEtnn lt setpoint gt Specifies the setpoint to use in the relative calculation 350 kG RE
100. s to hazardous live voltage can cause injury or death Lake Shore Hall generators are not designed for direct exposure to live voltage Exposing the Hall generator to live voltage can cause damage to the instrument Refer to the Lake Shore Magnetics Catalog for a list of compatible Hall generators manu factured by Lake Shore mw Lake Shore www lakeshore com CRYOTRONICS 24 CHAPTER 3 Installation If the control current enters the red lead with I connected to the positive terminal of the current supply and the magnetic field direction B is as shown in section 2 4 a positive Hall voltage will be generated at the Vy lead Reversing either the current or the magnetic field will reverse the output voltage 3 8 1 Polarity Model 425 Gaussmeter 4 1 General 4 2 Front Panel Description 4 2 1 Keypad Definition Chapter 4 Operation 4 1 General 25 This chapter provides instructions for the general operating features of the Model 425 gaussmeter Advanced operation including probe management is in Chapter 5 Computer interface instructions are in Chapter 6 FIGURE 4 1 Model 425 front panel Model 425 This section provides a description ofthe front panel controls and indicators for the The Model 425 has 14 keys separated into two groups on the instrument front panel Key Function Refer to section Max Hold Used to turn the max hold function on and off 4 5 4 Relative Used to
101. sa rene 41 USB Interface o esos te dian s eu tatis aon RUSO AA 41 62 1 Physical COMME HOM zine 41 6 2 2 Hardware Support ccc cece e ees 41 6 2 3 Installing the USB Driver ecesat iot hPEE PERPE EPI xe tes koere iiki 42 6 2 3 1 Installing the Driver From Windows Update in Windows Vista 42 6 2 3 2 Installing the Driver From Windows Update in Windows XP 42 6 2 3 3 Installing the Driver From the Internet 0 cece eee eee 42 6 2 3 4 Installing the USB Driverfrom the Included CD ROM 44 6 2 4 COMMUNICATION 5 ues cedes ce in oh toe v n OO US E ERR on re re FLA RT b ci ta 45 S241 Character nali 45 6 2 4 2 Message STINGS saprei ridire 45 6 2 5 MESSESFIONCONAIO iii arr ERU 46 Command SUMMA cirie cin ra ca 46 6 3 1 Interlace Commands ilaria 47 T ne PE E E ATI 55 KOE 55 ducto gp M 55 RaR MOUNINO arenili e ideata 56 Prope ACCESSO ES sii iii iaia 57 g REEN ES E E E E EEE neon 57 mw Lake Shore www lakeshore com CRYOTRONICS iv TABLE OF CONTENTS Chapter 8 Service Model 425 Gaussmeter IRE PR AA IE 59 54 General WOU DISS MO OUWNS ronnie aaa 59 9 2 TISBTTOUDIOSIIODEITIE asa cauti ronan rair A EES orata 59 SSCMMEIUENCI u ip EE 59 8 3 2 Existing Installation No Longer Working 59 8 3 3 Intermittent LockupS irritati 60 SRL LIVORNO iii encour ng Ee TEn EER
102. solute value used or algebraically inlcudes sign 1 magnitude check 2 algebraic check lt low value gt Sets the value the source is checked against to activate low alarm 350 kG lt highvalue gt Sets the value the source is checked against to activate high alarm 350 kG lt out in gt Specifies the alarm to trigger on value outside or inside of setpoints 1 outside 2 inside Turns alarm sort function on or off O off 1 on Specifies if the internal speaker will beep when an alarm condition occurs Valid entries 0 off 1 on ALARM 1 1 100 300 1 0 0 term turns alarm checking on activates alarm if the absolute value of the field is over 300 G or if the absolute value of the field is below 100 G sorting is turned off and instrument will not beep when an alarm condition occurs lt alarm sort gt lt audible gt Input Alarm Parameter Query ALARM term off on mode low value gt lt high value gt lt out in gt lt alarm sort gt lt audible gt term n n tnnn nnnEtnn tnnn nnnEtnn n n n refer to command for description Alarm Status Query ALARMST term lt state gt term n lt state gt 0 Non alarming 1 Alarming AUTO Input Format Example AUTO Input Returned Format BEEP Input Format Remarks BEEP Input Returned Format Remarks BRIGT Input Format Remarks BRIGT Input Returned Format DFLT Input Remarks KEYST Input Returned
103. strument off and back on These features support increased productivity allowing you to spend lesstime setting up your instrument and more time working on the task at hand E Lake Shore www lakeshore com CRYOTRONICS 2 CHAPTER 1 Introduction 1 1 2 DC Measurement Mode 1 1 3 AC Measurement Mode 1 2 Measurement Features 1 3 Instrument Probe Features 1 3 1 Probe Field Compensation 1 3 2 Probe Information 1 3 3 The Probe Connection Model 425 Gaussmeter Static or slowly changing fields are measured in DC mode In this mode the Model 425 uses probe field compensation to correct for probe nonlinearities result ing in a DC accuracy to 0 20 Measurement resolution is enhanced with internal filtering allowing resolution to 43 4 digits with reading rates to 30 readings per sec ond over the USB interface In addition to the DC measurement mode the Model 425 offers an AC measurement mode for measuring periodic AC fields The instrument provides an overall frequency range of 10 Hz to 10 kHz and is equipped with both narrow and wide band frequency modes While in narrow band mode frequencies above 400 Hz are filtered out for improved measurement performance The Model 425 offers a variety of features to enhance the usability and convenience ofthe gaussmeter Autorange in addition to manual range selection the instrument automatically chooses an appropriate range for the measured field Autorange works in DC and AC
104. the Device Manager window under the Ports COM amp LPT device type 3 Check thatthe correct settings are being used for communication Refer to section 6 2 2 for communication port configuration details 4 Check cable connections and length 5 Send the message terminator 6 Send entire message string at one time including the terminator Many terminal emulation programs do not 7 Send only one simple command at a time until communication is established 8 Besure to spell commands correctly and use proper syntax 8 3 2 Existing 1 Power the instrument off then on again to see if it is a soft failure Installation No Longer 2 Powerthe computer off then on again to see if communication port is locked up li 3 Checkall cable connections Working 4 Check that the com port assignment has not been changed In Microsoft Windows the com port number can be checked in the Device Manager window under the Ports COM amp LPT device type mw Lake Shore www lakeshore com CRYOTRONICS 60 CHAPTER 8 Service 8 3 3 Intermittent Lockups CAUTION 8 4 Line Voltage 8 5 Factory Reset Menu 8 5 1 Default Values Model 425 Gaussmeter 5 Check that the USB driver is installed properly and that the device is functioning In Microsoft Windows the device status can be checked using the Device Man ager Click Ports COM amp LPT or Other Devices in the device type list and then right click Lake Shore Model 425 gauss
105. the probe model LOCKED A change was attempted with the keypad locked Illegal Invalid HMPEC Improper cable attached during the HMPEC programming process operation error cable section 5 5 1 messages Improper cable attached during the HMCBL programming process Invalid HMCBL cable section 5 5 1 TABLE 8 2 Model 425 error messages The auxiliary I O probe input and USB connectors are shown in FIGURE 8 1 through FIGURE 8 3 and defined in TABLE 8 3 through TABLE 8 5 het a d RENE HMM py PDC tna rs CMR OP LAT En EN I exe atom ym T ws VV p A N RE ni f Jj 7 f M gt M manm een it CRA AE re it rt o a I L ae ae Pode Mo ri LIII Ira By d Pe Lgs rA Deci IF FEL rM der Dr a petu _ Lo P Ce eae gt HM i RTE Nd LIU FIGURE 8 1 Auxialiary I O socket mw Lake Shore www lakeshore com CRYOTRONICS 62 CHAPTER 8 Service recite re pece 1 Monitor out Ground 2 Internal use only 15 Ground 3 Internal use only 16 Ground 4 No connection 17 No connection 5 Internal use only 18 No connection 6 Internal use only 19 No connection 7 No connection 20 No connection 8 Relay 1normallyopen 21 No connection 9 Relay 1 common 22 No connection 10 Relay 1 normally closed 23 No connection 11 Internal use only 24 No connection 12 Internal use only 25 No connection 13 Internal use only TABLE 8 3 Auxiliary I O connector details PROBE INPUT FIGURE 8 2 Probe i
106. tin guish this errorfrom what is the desired field reading unless the off axis field can be eliminated When measuring AC fields the stray AC fields that are present can induce a voltage on the leads which results in reading error The effect ofthis error increases with fre quency and proximity to the field being measured The induced voltage can be many times greater in magnitude than the actual field being measured Care should be taken to keep the probe stem and cables away from the field being measured to mini mize this error Magnetic field measurements are often taken in very cold environments Conditions inside superconducting magnets and around many high energy physics experiments involve cryogenic temperatures Lake Shore offers two Model 425 gaussmeter probes capable of operation in temperatures down to 1 5 K 271 65 C These are the axial HMCA 2560 WN and the transverse HMCT 3160 WN for cryogenic probe specifica tions referto the Magnetics Catalog on the Lake Shore website Section 2 7 1 through section 2 7 3 discuss several factors that may affect either the accuracy or lifetime of these probes Care must be taken to minimize the thermal expansion stress rate during exposure to or removal from cryogenic temperatures If possible allow the temperature to change at a slow rate Sudden dipping into cryogenic liquid or removal to room tem perature is not advised Even with the greatest of care cryogenic probes have a finite lif
107. touching them Do Not Substitute Parts or Modify Instrument Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to an authorized Lake Shore Cryotronics Inc rep resentative for service and repair to ensure that safety features are maintained Cleaning Do not submerge instrument Clean only with a damp cloth and mild detergent Exte rior only mw Lake Shore www lakeshore com CRYOTRONICS O AAEH Qe CHAPTER 1 Introduction Direct current power line ci Alternating current power line Alternating or direct current power line A Three phase alternating current power line Earth ground terminal AN Protective conductor terminal Frame or chassis terminal On supply Off supply FIGURE 1 5 Safety symbols Model 425 Gaussmeter Equipment protected throughout by double insulation or reinforces insulation equivalent to Class Il of IEC 536 see Annex H CAUTION High voltages danger of electric shock background color yellow symbol and outline black CAUTION or WARNING See instrument documentation background color yellow symbol and outline black 2 2 1 DCMeasurement 7 Chapter 2 Background 2 1 General 2 2 Model 425 Overview 2 2 1 DC Measurement 2 2 2 AC Measurement Wide band Computer i interface This chapter provides background information related to the Model 425 gaussmeter It is intended to give insight into th
108. tringent applica tions The measured field is the average of the active area but without severe gradients therefore the measured value accurately represents the true field Field mapping with standard probes is also practical ifa mapping resolution of 1 mm 0 04 in or greater is acceptable m Small active area HSE and HST probes with a smaller active area are also available from Lake Shore for measurements in severe gradients or for high resolution mapping applications m UHS probes UHS probes have a very large active length up to 89 mm 3 5 in They are designed to measure very low magnitude large volume ambient fields with little gradient All Hall effect probes are fragile The sensor normally located at the tip of the probe stem must not be bent physically shocked or abraded It may be tempting to choose a probe with the thinnest transverse stem or smallest diameter axial stem however itis always bestto choose the most robust probe that fits the immediate application For example the HMMT 6J04 VR aluminum stem is less prone to damage than the HMFT 3E03 VR flexible stem and the HMMA 2502 VR 6 35 mm 1 4 in diameter aluminum is more durable than the HMNA 1904 VR 4 76 mm 3Aein diameter fiberglass with its exposed Hall sensor Never fasten a probe stem to another object If a probeis clamped always apply the clamp to the handle Improper mounting can cause damage to the probe The user must consider all the possibl
109. try or cancel all changes and return from numeric data entry mode if it is atthe first position When using numeric entry the first parameterto be entered is the range Choose arange that is appropriate for the number being entered This affects both the decimal point location as well asthe units multiplier The next item to be entered is the sign of the number if the alarm function is set with the algebraic setting section 5 2 2 The final item to be entered is the number with five digits of reso lution Related setting selection and data entry sequences are often chained together under a single key To bypass a feature without changing it press Enter before pressing an arrow key To return to the normal display in the middle of a setting sequence press Escape before pressing an arrow key Changes entered before Escape is pressed are kept This section describes features of the display that appear during normal operation In normal operation the two row by twenty character liquid crystal display LCD pro vides readings defined by the selected measurement features on the top row and spe cial information or readings on the bottom row Other information displays when using the various features on the keypad The computer interface provides readings at a rate of 30 rdg s and the display will update at 3 rdg s independent of the filter Field units Relative on Field polarity DC mode only G T Oe A m DC Alarm Field or relative reading
110. turn the relative mode on and off 4 5 6 Units Allows configuration of the field units of measurement 4 4 1 DC RMS Used to select between DC and AC root mean square RMS field measurement modes Press and hold for 3 s 45 to select filter in DC mode or to select between narrow and wide band modes in RMS mode Range Allows for selection between field measurement ranges and autorange 4 5 3 Max Reset Resets the maximum field reading 4 5 5 Alarm Relay Allows configuration of the alarm setpoints and relay Press and hold for 3 s to configure alarm parameters 5 2 Interface Displays the instrument baud rate Press and hold for 3 s to adjust the display contrast 6 2 Probe Setup Used to display the probe serial number and to turn field compensation on or off Press and hold for 3 s for 54 HMPEC HMCBL extension or user cable programming Zero Probe Used to zero probe offsets or null the effects of ambient low level fields Press and hold for 3 sto clear the 4512 results of zero probe st Used to navigate menus and to select settings 4 2 2 Eca OMEN Cancels a selection Press and hold for 3 s to reset the instrument to default values and to display the firm 42 2 ware version and the instrument serial number N Used to accept a selection Also used to navigate deeper into a menu screen Press and hold for 3 s to lock or 42 unlock the keypad TABLE 4 1 Keypad definitions wu Lake Shore CRYOTRONICS www lakeshore com 26 CHAPTER 4 Operatio
111. xtent prohibited by applicable law neither Lake Shore nor any of its subsidiaries affiliates or suppliers will be held lia ble for direct special incidental consequential or other damages including lost profit lost data or downtime costs arising out ofthe use inability to use or result of use ofthe product whether based in warranty contract tort or other legal theory regardless whether or not Lake Shore has been advised of the possibility of such damages Purchaser s use of the Product is entirely at Purchaser s risk Some countries states and provinces do not allow the exclusion of liability for incidental or consequential damages so the above limitation may not apply to you 12 This limited warranty gives you specific legal rights and you may also have other rights that vary within or between jurisdictions where the productis purchased and or used Some jurisdictions do not allow limitation in certain warranties and so the above limitations or exclu sions of some warranties stated above may not apply to you 13 Except to the extent allowed by applicable law the terms of this limited warranty statement do not exclude restrict or modify the mandatory statutory rights applicable to the sale ofthe 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 a
112. y pressed since last query u Lake Shore www lakeshore com CRYOTRONICS 50 CHAPTER 6 Computer Interface Operation LOCK Input Format Remarks LOCK Input Returned Format MXHOLD Input Format Example MXHOLD Input Returned Format MXRST Input Remarks OPST Input Returned Format Remarks PRBFCOMP Input Format Example Model 425 Gaussmeter Front Panel Keypad Lock Command LOCK lt state gt term n lt state gt O Unlocked 1 Locked Locks out all front panel entries Instrument settings can still be viewed but not changed refer to section 4 6 Front Panel Keypad Lock Query LOCK term state term n refer to command for description Max Hold Command MXHOLD off on term n off on specifies max hold on or off 0 Off 1 On MXHOLD 1 term turns the max hold feature on the Model 425 displays the max value Max Hold Query MXHOLD term off on term n refer to command for description Max Hold Reset Command MXRST term Resets the stored maximum field reading and sets it equal to the present field reading Operational Status Query OPST term bit weighting term nnn Returns the sum of the bit weighting of the instrument status bits Bit Me ns Description 0 1 No probe this bit is set if no probe is attached to the instrument 1 2 Field overload this bitis set when the field reading is in an overload condition 2 4 New field rea
113. y 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 command is described in section 6 3 Terminators must be sent with every message string A query string is issued by the computer and instructs the instrument to send a response 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 Query mnemonics and parameter data if necessary are described in section 6 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 instrument s response or answer to a query string 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 section 6 3 The response is sent as soon as possible after the instrument receives the query mw Lake Shore www lakeshore com CRYOTRONICS 46 CHAPTER 6 Computer Interface Operation 6 2 5 Message Flow It is important to remember that the user program is in charge of the USB communi Control cation at all times The instrument cannot initiate c

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