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Three-axis Hall Magnetometer THM1176 User`s Manual

1. Sets up all measurement parameters Serial no Control Select the instrument you want to control by its serial number The serial number is printed on the label located on the instrument electronics Info Display The instrument information returned by the selected THM1176 in response to the IDN command see Section 6 5 IEEE 488 2 Common Commands Update rate Control Sets the interval between measurements in seconds You can slide the slider or edit the text display Notes for the handheld version 1 the slider scale Thi E T BS oad represents the power of ten 2 use the virtual keyboard to edit the text display see Section Three axis Hall Magnetometer THM1176 9 0 0 Rate Display red light no label See 0000004 RY Section 4 1 Metrolab Instruments SA f THM1176 0000004 1 0 Averaging Control Sets the number of data points that are averaged together for each measurement displayed Data averaging reduces the noise the peak to peak noise level will be reduced by approximately the square root of this number The data points are acquired in a single burst at the maximum acquisition rate see Section 7 1 Range Control Selects the maximum value that can be measured Auto automatically selects the optimum range for each measurement Power saver Control enables or disables the power saver feature of the THM1176 This is especially useful for the handheld version Note t
2. 07 08 Copyright 2008 Metrolab Instruments SA Command Description INITIATE_CL EAR Clears the device input and output buffers TRIGGER Assert bus trigger SRQ Requests service from host READ_STATUS_BYTE Read status byte REN_CONTROL Remote Enable no effect on THM1176 GO_TO_LOCAL Enable local controls no effect on THM1176 LOCAL_LOCKOUT Disable local controls no effect on THM1176 6 5 IEEE 488 2 COMMON COMMANDS As any IEEE 488 2 compliant instrument the THM1176 supports the following commands Command Name Description CLS Clear status Clear all event registers and queues not enable registers and error buffer ESE lt NRf gt Program event enable Program standard event enable register ESE Event enable query Read standard event enable register ESR Event status query Read standard event register and clear it IDN Identification query Return manufacturer model serial number software version Note that this query returns Arbitrary ASCII Response Data see IEEE488 2 standard and cannot be followed by another query in the same command sequence OPC Set operation complete Set the operation complete bit in the standard event register after all commands have been executed OPC Operation complete query Returns an ASCII 1 after all
3. Merrolah 31 www metrolab com THM1176 User s Manual v 1 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA As shown in the figure below taken from the IEEE 488 2 standard each of the registers above is actually a set of three registers S21 o Condition Register Transition Filter Selects which transitions Event Enable Register 1 Selects which Events can set the Summary Message of Condition bits will set corresponding event bils ss f or Lorboth Event Register Latched Conditions Logical AND of latched event condition bit with corresponding event enable bil Logical OR Summary Message o Condition Register Read only register that is constantly updated to reflect the current state of the instrument o Event Register Transitions in a Condition Register are latched in the corresponding Event Register The THM1176 only latches transitions from 0 to 1 Event Registers are cleared when read o Event Enable Register A mask indicating what bits in the Event Register are included in the Summary bit The enable mask of the Status Byte is called the Status Enable register and it determines which bits cause an RQS ReQuest for Service 6 4 USBTMC USB488 CONTROLS The following functions are supported directly by the USBTMC USB488 protocol Historically these correspond to dedicated hardware signals in IEEE 488 1 HPIB or GPIB Merrolah 32 www metrolab com THM1176 User s Manual v1 1 r1 0
4. CONDition Read operation condition register ENABle Query enable register ENABle lt numeric_value gt Set enable register 0 by default PRESet Reset OPERation and QUEStionable enable registers Command Parameters Description SYSTem gt ERRor NEXT Query error queue VERSion Query SCPI version e g 1999 0 HELP HEADers List all available commands SYNTax lt command_header gt List syntax for a command SLEEp Power down the acquisition electronics Power up is automatic at the next acquisition but takes approximately 100 ms Merrolalh 39 www metrolab com THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description TRIGger COUNt Query trigger count COUNt lt value gt Set the number of triggers required to complete an acquisition lt value gt min 1 max 2048 def 1 Note resets the trigger system SOURCe Query trigger source SOURce IMMediate TIMer BUS DEFault Trigger source IMMediate no wait TIMer periodic trigger BUS USB488 TRIGGER IMMediate by default Note resets the trigger system TIMer Query trigger timer TIMer lt meas_time gt Set period for periodic trigger lt meas_time gt min 488us max 2 79s def 0 1s Note resets the trigger system Command Parameters Description UNIT Query units UNIT T MT MAHZp GAUSs KGAUss Set units in which fl
5. for repair however it will of course be fully tested calibrated and guaranteed e Warranty The standard warranty period is two years from the date of purchase During this period Metrolab will replace a failing unit free of charge unless it is clear that the unit has been abused crushed probe or electronics torn cable etc We do not assume responsibility for consequential damage for example to your PC Merrolah 10 www metrolab com THM1176 User s Manual lt USING THE THM1176 4 User Interface v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA The THM1176 can be used as a laboratory instrument plugged into a Personal Computer PC or optionally as a handheld instrument The di splay of the handheld instrument will vary slightly from the illustrations below however the utilization is the same except when noted 4 1 NUMERIC DISPLAY Metro Three axis Hall Magnetometer THM1176 Displays the current measurement results on a numeric display B Display Absolute field strength Bx By Bz Display X Y and Z components of field strength See Section 2 3 Precautions for the orientation of the axes Max Control When checked capture the absolute maximum of B Bx By or Bz respectively This allows you to find the approximate maximum field strength in a volume Rate Display Indicates if the update rate is slower than requested Use the Setup page to change
6. If needed the offset correction procedure will measure and correct this offset The correction value is written to flash memory so that the same correction will be applied the next time the instrument is powered up Readout options The three field components are always acquired but the readout can be limited to any selected components The readout can include a single measurement or an entire array of measurements and can be formatted as a binary block or as an ASCII message The field values can be returned in Tesla mTesla Gauss kGauss or equivalent proton NMR frequency A timestamp 10 ms resolution and temperature arbitrary units not calibrated can also be read out INTERFACE USB interface Compliance with the USB 2 0 mechanical electrical and protocol standard provides basic connectivity with any USB capable computer The instrument supports USB full speed communication 12 Mbps Standardized USB class driver Compliance with the USB Test amp Measurement Class USBTMC allows the instrument to be connected without installing a custom USB driver All that is required is a generic class driver for test and measurement equipment as provided by suppliers of instrumentation software notably National Instruments LabVIEW The software supplied with the instrument includes the National Instruments USBTMC driver Standardized IEEE488 2 protocol Compliance with the USB488 protocol specification for USBTMC provides all
7. Internal buffer size 2048 samples Bandwidth DC to 1 kHz Resolution 100 mT range 500 mT range 3 T range 20 T range No averaging 300 uT 500 uT 3 mT 15 mT Averaging 100 samples 30 uT 50 uT 300 uT 1 5 mT Accuracy The greater of 1 of reading or specified resolution Specified 0 3 T User offset correction To be performed before each series of measurements in Zero Gauss Chamber supplied 7 2 INTERFACE Interface USB 2 0 full speed 12 Mbps Class USB driver USBTMC USB Test amp Measurement Class USB488 DFU Device Firmware Upgrade Protocol IEEE 488 2 SCPI Standard Commands for Programmable Instruments Connector USB Type A Power USB bus powered 4 3V to 5 25V 35 mA min idle power saver on 90 mA max Wake up time from power 100 ms saver 7 3 OPERATING CONDITIONS Operating temperature 0 C to 40 C Storage temperature 20 C to 60 C Operating magnetic field Instrument electronics 3 T max Merrolalh 42 www metrolab com THM1176 User s Manual 7 4 v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA MECHANICAL Size Instrument electronics Probe with housing Probe without housing 76 x 22 5 x 14 mm 113 x 16 x 10 mm 65 mm 4 1 mm thick e A 6 2 mm 47 mm 10 mm thick 16 mm Stationary mounting point For M2 5 screw not included Note to avoid breaking the mounting point use a s
8. Jo Retrieve the next entry in the error event queue source Clear all event registers and queues and Reset the OPERation and QUEStionable enable registers to their default values Enable In The new value when setting the value of an enable register Response Out Response to command Enable out Out The current value when retrieving the current value of an event or event enable register 5 14 STRAIGHTEN Straighten Compensate measurements for a possible small FEA ER A N a FLSA rotation of the sensor IC relative to the ceramic VISA session Dap VISA session plate that forms the base of the IC package Z ll l BEE eg Bx in By in Bz in In X Y and Z components dE respectively of the measured field vector o d o Bx out By out Bz out Out X Y and Z Bx in By in Bz in components respectively of the corrected field 0 00000 J 0 00000 9 00000 vector Bx out By out Bz out Rotation matrix Out Rotation matrix for this EM eech SE instrument The matrix transforms the measured F pmm 7 field vector to a coordinate system fixed relative to rror in no error Error out Es the ceramic plate the forms the base of the sensor ae IC package The field vectors are considered J column vectors source Merrolah 23 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 5 15 TRIGGER Copyright 2008 Metrolab Instruments
9. Please report to Metrolab the circumstances under which you received this error 9 7 2 205 Measurements were over range The field value exceeded the selected range Merrolah 51 www metrolab com
10. a VISA Read and sends a VISA Clear in case of error This VI is only used as a sub VI for Write and Read vi See VISA Read for a definition of the parameters ig J 0 d 0 source source 5 9 RESET RESET Reset the instrument to startup settings Acquisition buffer empty aar SE Trigger source Immediate a amp zi Se Trigger count 1 Error in no error Error out status code di Jo source Trigger timer 100 ms Range Auto Calibration state On Units Tesla Format ASCII Merrolah 21 www metrolab com THM1176 User s Manual 5 10 REVISION QUERY v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Revision Query VISA session Dup VISA session zl aa Instrument Driver Revision Instrument Firmware Revision Error in no error Error out Queries the current instrument firmware revision and instrument driver revision Instrument Driver Revision Out The revision of the instrument driver software Instrument Firmware Revision Out The revision of the instrument firmware 5 11 SELF TEST Self Test Run instrument self test Note VISA sessi ARAE T THM1176 currently does not support zi Hi f Self test response Out Response from TST Solf test response self test command Error in no error Error out status code s 0 source 5 12 SEN
11. but could not be executed because the interpreted value was outside the legal range as defined by the device e Anumeric parameter is smaller than the allowable minimum or larger than the maximum e A character parameter does not match one of the allowable choices e MEASure READ the lt expected_value gt is too large e FETCh fetching more data than what was acquired e MMEMory DATa the file does not exist e SENSe the requested range does not exist or e SYSTem HELP requesting help for a non existent command 9 3 3 225 Out of memory The device has insufficient memory to perform the requested operation e when writing the new User Offset Zero file to Flash 9 4 300 DEVICE DEPENDENT ERRORS 9 4 1 363 Input buffer overrun The internal acquisition buffer was overrun This happens when in Mer triggered mode and the host did not FETCh the data in time Merrolah 49 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 9 5 400 QUERY ERRORS 9 5 1 400 Query error Generic query error e Device being cleared when query was received On the THM1176 no other conditions should generate this error If this is not the case please report to Metrolab the circumstances under which you received this error 9 5 2 410 Query INTERRUPTED The host has sent a new command before finishing reading the response to a preceding query 9 5 3 420 Query UNTERMINATED The host is
12. commands have been executed RST Reset Reset device to power on configuration SRE lt NRf gt Program status enable Program status enable register Important you must also enable service requests on the host See Section 6 7 for details SRE Status enable query Read status enable register STB Status byte query Read status byte register TRG Trigger Generate bus trigger TST Self test Query Perform complete self test return 0 if successful 1 if not WAI Wait to Continue Wait until previous commands have completed 6 6 SCPI COMMANDS In the command definitions below the following conventions are used Merrolah 33 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA optional keywords or parameters lt gt value The abbreviated form of each command is written in capital letters For example the MEASure command can be written as MEASURE or MEAS or since capitalization doesn t matter measure or meas Each command is presented with its subcommand s indented below it For example FETCh SCALar Fetch values acquired during last MEASure READ or INITiate FLUX 2X lt digits gt Fetch x component of flux lt digits gt Fetch y component of flux According to this table the following commands are legal FETC SCAL FLUX Y FETC same as above omitting optional keywords FETC X fetc
13. m Se empty a file name is requested first Record File Name Display no label Displays the name of the recording file C Control Clear button clears the Record File Name so that the next time you press the Record button you will be prompted for a new file name i Control information button enables or disables the display of previously recorded measurements on a graph Information File Name Display no label Displays the name of the file currently being displayed 235 237 5 Bz Cu DES Information display Display no label graph n of previously recorded measurements The X seat 219 57 om Bl a axis represents the time stamp converted to cursori 234 77 10 33925 58 a seconds the Y axis the field strength in Tesla B Bx By Bz Control Enables or disables the display of the corresponding data Note not on the handheld version Merrolah 12 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Cursor Control Enables or disables the display of the cursors and cursor palette The cursor palette contains the following tools for each cursor Note not on the handheld version e Cursor name e Current X and Y values e Enable or disable movement with keypad e Change the cursor appearance e Allow the cursor to move freely snap to the nearest data point or lock onto a field component By default
14. the THM1176 software by running setup exe in the THM1176 subdirectory PC Measurement Start the THM1176 measurement software If you used the standard installation options a THM1176 link is located in the THM1176 program group of the All Programs menu Plug in the THM1176 The first time the Windows New Hardware Wizard will run which requires access to an Administrator account On the first dialog choose not to connect to Windows Update on the second choose to install the software automatically Subsequently chimes will indicate when the system has started up and the measurement software should automatically recognize the THM1176 and start measuring Place the probe into the magnet You can remove the probe cap to access narrow gaps see Chapter 3 Overview See Chapter 4 User Interface for details on using the software Be sure to check the offset before each series of measurements by placing the probe in the Zero Gauss Chamber and plotting the results If the offset is higher than desired leave the probe in the Zero Gauss Chamber and perform the User Offset Correction procedure using the Offset ZERO button on the Setup page PC Software Development Insert the installation CD and open the PC directory Copy the LabVIEW folder to your hard drive The API subfolder contains the Application Programming Interface see 5 Application Programming Interface The UIF folder contains the source code of the THM1176 measurem
15. to connect PDA to PC Pre installed acquisition software with licenses from Metrolab including free updates and from National Instruments CD with acquisition software for PC Windows XP Vista and PDA Windows Mobile LabVIEW source code for all PC and PDA software and user s manual Carrying Case PDA type Windows Mobile 5 0 with USB host interface PDA size 127 x 75 x 21 mm PDA weight 230 g with 2600 mAh battery stylus and USB adaptor cable Display 64K colour TFT LCD 3 5 240 x 320 pixels Input Device Stylus or fingertip Connectors Power jack 2 5mm audio headset jack 26 pin connector for ActiveSync USB 1 1 host and USB 2 0 client CompactFlash and SDIO expansion slots Audio Built in microphone and speaker Memory 128 MB SDRAM 256 MB NAND Flash Wireless LAN IEEE 802 11 b g internal antenna Bluetooth V2 0 EDR class 1 Battery life 6 hours min Record file format ASCII tab delimited compatible with Desktop file format Pre loaded software Acquisition software same functionality as desktop software Word Mobile Excel Mobile PowerPoint Mobile Outlook Mobile IE Mobile MSN Messenger Client Windows Media Player 10 2 Mobile ActiveSync Client Socket Mobile Wi Fi Companion Programmable Home Screen Calculator Utility programs PDA operating temperature 0 to 50 C PDA operating magnetic field 1 T max The PDA may experience forces as high as 50 N N
16. 24 e Re UC RE 25 PROGRAMMING THE THM1176 2 cccceeeeeeeeseeeeeeeeeeeeeseeeeeeeenseeneseaeeaeeeseeseeeseasesseseaneaeeeseeseeneeas 26 6 HSblotertaee SEENEN ENEE ces eaaa aaa a 26 Od ETC EE 26 6 2 SCP Instrument dl ENEE 27 6 3 IEEE 488 2 SCPI status registers ceeeseceesecceeceeeeeeeeeeeeeseeeeeeneeeeesaeesesaneeseeeesenaaeeseeeessseenseeeeeenenes 29 6 4 USBIMC USB488 Controls six i cccccccccccsencueestceesigennndgcad cssneensiecteescceecuddeeessesteeganeesiicesadeeaedesctendvanpateceeeniotas 32 6 5 IEEE 488 2 Common Commande ssissssssisrcerirnerieriiuanrinacrrunnrnnnrceancennn cienne raneren craadcna nacer uara anaran naa e 33 626 SCGPLCOMMANA EE 33 6 7 Programming Hintsasen ie nair a a iai aeaa e aaea 40 PREFERENCE rra ro aaan Aa Aaaa eraa a ara a a NEESS EES aada 42 T Technical Specification sssini anaa aa aaa 42 771 dE TE 42 eet MMOH ACC eegen e dree esdtdeerdeeg ide eege Eer enee ege eege E 42 7 3 Operating e EE 42 HPA Me chanical oriris eaaa pa cies gdivadbe bast be vgcecagastag bibexcane eta ueie Alun x a a a N EEEE sde 43 1 9 KieektOgr serrin cea tect seas cdessautens EE EES 43 7 6 Ee EE A4 7 7 Warranty Calibration Certification and Maintenance 45 PREFERENCE iiicvccccsccde se cctscensevetescedecessunsdene cesedecie ESCHER EENS EES Eege 46 8 Sensor Technical DeSCriptiOn sscccccsseeeeeeeeeeeeeeeeeseceeeeeeeseeeeeeensneeeeeeensneeeeesenseeeneeenseeeeneess 46 REFERENCE seess coeacehiiss snaune
17. METROO Magnetic precision has a name Three axis Hall Magnetometer THM1176 User s Manual Version 1 1 Revision 1 0 July 2008 THM1176 User s Manual v1 1 61 0 07 08 CONTENTS GETTING STARTED aieiaiee cece dctnceente chet ada eaaa aeda ara aa daa aandaa Sdad Esada ata 1 T de GL TO d VE 1 GETTING STARTED bi viccceccsscecsceicnntesteiceccecesssceaduecedee peddesnvcennnccuenesacuesuvdssxveuhwecsadenttes siddeeavcussesctetedcereres 2 2 Quick Start Guide in ccccccc cc sccc cee cecccctececenccee ee ctencte E EE ETEA E fenceadeceeeceoueeeeceoncee 2 2 1 Using the THM1176 with amp ele 2 2 1 1 PC Software Jnsialaton nnne 2 2 1 2 PC Measurement asec eeecesscecceeccennneneeeeccnaaeeeeeescaaaaeeenesacaaaneeeesaaaanesecsaceaaaeeseessenanesestasenssneseesaness 2 2 1 3 PC Software Development 2 2 2 Using the THM1176 with the Handbeld AAA 3 2 2 1 Handheld Assembly ressis e A E E E TAE 3 2 2 2 Handheld Measurement ennnen 3 2 2 3 Handheld Software Development ccccecccceseneeeecanereneneetenenenesasessnaneeneaaeeseaeenenensesenaneneenanenenes 3 Doe E Ge EE 4 Poe Re 5 USING THE THM1176 eege EES EENS EENS EES 6 B e NET 6 3 1 Measurement EEESC EEEEEEESOEEEEEEESOEEEEESESEEEEEEESEEEEEEESOEEES SEEE EEEE EEEE E EE 6 C A NEIE O E E E A E E A T E E N E EEE 7 3 3 Probe Mechanical DeSiQn ccescceesseeeeeeeeeseseneeeeseeeseeaeeeceaneeessesesesaneesseesesssaaeeeseaeesesaseseeseseneneeseneaeess 8 BoA DESKOP Kibosn
18. Metrolab s electronic newsletter published twice yearly see the Newsletter Subscription page of the News section of Metrolab s website and the News articles on Metrolab s website The Download page of the Metrolab website htip download metrolab com will always contain the latest versions e Firmware upgrades The THM1176 is designed such that you can upgrade the firmware yourself Firmware upgrades are a delicate procedure as a failure may render the instrument unusable Metrolab has made every effort to make the process foolproof but please take your time and follow the instructions provided with the upgrade carefully e Upgrades to the PDA software To comply with the license associated with the LabVIEW PDA module Metrolab distributes upgrades to the PDA software in an encoded file You need to contact Metrolab for the password for this file Please send an e mail with the serial number of your THM1176 to contacts metrolab com The serial number is printed on the label located on the instrument electronics It is also displayed on the Setup page of the measurement software e Repairs Due to the highly integrated construction of the THM1176 Metrolab cannot replace individual electronic components If you send a THM1176 back for repair we will send you a replacement unit at a standardized exchange price please contact Metrolab for a quotation The replacement unit may contain parts recovered from units previously sent in
19. SA TRIGger VISA session Dup VISA session E E Function Source Setup query IMMediate Count Period s Continuous 1 0 1 Ce Response Error in no error Error out status code GA y source Manages all functions of trigger system Function In Select function to be performed Setup set up the trigger system with the parameters given Setup query get current trigger setup INITiate enable the trigger ABORT abort any pending triggers Source In Trigger source for Setup function IMMediate no wait Mer periodic trigger BUS USB488 trigger Count In Trigger count for Setup function Period In Trigger period for Setup function Continuous In Continuous initiation mode for Setup function Note continuous initiation only works with a periodic trigger Response Out Response to any of the query functions 5 16 UNIT VISA session I 4 Function Units query Ez UNIT Dup VISA session F S Units Units out T Il Error in no error status code fl d source Error out Sets the units in which measurements are returned or queries the currently selected units Note that units are only used if FORMat is Ascii and CALibration STATe is On Query In If set returns current units If not sets units Units In If Query is false selects units in which measurement results are to be retu
20. SE SENSe Sets the measurement range or gets the currently selected range Note that it can be very useful to Rh cousins Ao ER get the currently selected range after performing e an auto ranging measurement H EL S Function Range Function In Whether to set the range or to get SENSe Query Auto the currently selected range Range sat Range In The range for when setting the range Range out Out The range for when getting the Error in no error Error out currently selected range status code di Jo y source Merrolah 22 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 5 13 STATUS Collects all commands concerning the IEEE488 2 SCPI status system in the THM116 See Section 6 3 for more details about the status registers Function In The function to perform For each of the four status registers Status Byte Standard Event Status Register OPERation Status and QUEStionable Status you can Get and clear the current value of the event STATus register VISA session Dup VISA session Get the current value of the event enable k k register Function Enable Set the event enable register atate aye query Dem In addition for the OPERation and QUEStionable BE Enable out Status registers you can 0000 Get the current value of the condition register Error in no error es Se Finally you can code
21. all parameters affecting the update rate Units Control Selects the units in which to display the measurement results T Tesla mT milli Tesla 1 T 10 mT MHz p NMR equivalent frequency of proton 1 T 42 5775 MHz p G Gauss 1 T 10 G kG kilo Gauss 1 T 10 kG Hold Control Hold or freeze the current measurement Merrolah 11 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 4 2 PLOT DISPLAY Displays the current measurement results on a me ROTO strip chart display The y axis is auto ranging and Three axis Hall Magnetometer THM1176 the scroll rate is fixed B Display Displays amplitude of B Bx By and or Bz on a strip chart display B Bx By Bz Control Enables or disables the display of the corresponding data on the strip chart display Note this does not work on the handheld version B Display See Section 4 1 Units Control See Section 4 1 Rate Display no label See Section 4 1 Hold Control See Section 4 1 4 3 FILE DISPLAY Allows recording the measurement data to a file and displaying the data in a recording file IT E T RS oad See Section 2 3 for the format of a recording file Three axis Hall Magnetometer THM1176 R Control Record button enables or disables 5 recording Once pressed data is recorded until D EE ed pressed again If the Record File Name is
22. asurement for temperature variations Even so offset remains a significant source of error Merrolalh 46 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Where does offset come from One common source is misalignment of the terminals As shown in the figure the effect effect can be modeled with a resistance network where the the longer current paths result in higher resistances and vice vice versa In our example the resulting offset voltage would be would be negative But if we exchange the current and voltage voltage leads thereby functionally rotating the Hall element by element by 90 the offset voltage becomes positive It is important to note that the Hall voltage is unaffected by this rotation The MAG3D exploits this effect in two ways The spinning current technique where the voltage and current leads are are rapidly switched back and forth and the results averaged averaged compensates for manufacturing imperfections such as terminal misalignment In addition by wiring orthogonally oriented pairs of sensors in series the MAGS3D increases its sensitivity while at the same time compensating for dynamic offset errors This includes the planar Hall effect whose magnitude changes sign when the current direction is rotated by 90 The combination of these techniques results in a sensor with significantly reduced offset offset drift and s
23. both cursors are locked onto B e Keypad for moving the enabled cursor s left right up or down Display controls Control at bottom of graph allow you to zoom scroll and move the cursors The following controls are provided Note not on the handheld version e Scroll bar scroll the x axis time e Cursor Movement Tool Moves the cursor on the display Note the cursors must first be enabled with the Cursor button e Zoom Zooms in and out of the display Opens a pull down menu with the following options o Zoom to Rectangle click a point on the display you want to be the corner of the zoom area and drag the tool until the rectangle covers the zoom area o X zoom zoom in on an area of the graph along the x axis o Y zoom zoom in on an area of the graph along the y axis o Zoom In about Point click a point you want to zoom in on Press and hold the lt Shift gt key to switch between Zoom In and Zoom Out o Zoom Out about Point click a point you want to zoom out from o Zoom to Fit autoscale the x and y scales to show the entire chart e Panning Tool Picks up the plot and moves it around on the display B Display See Section 4 1 Units Control See Section 4 1 Rate Display no label See Section 4 1 Hold Control See Section 4 1 Merrolah 13 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 4 4 SETUP DISPLAY
24. ceedesecancenvattenerarcesuancenasondeneuacanstacaensucrscaecoseaesancenedenseaceets 50 9 6 2 103 Wrong units for parameter isisisi nei eani A a aariaa 50 9 7 200 Instrument Dependent Execution Errors 000 eecceeeeseeeeeeneeeeseeeeseeeeeeeneeeesaeeeesaaeeseeaeeeseneeteeeaeeenaes 50 GE E ATERT 50 9 7 2 205 Measurements were OVES FANGE oie ceeseecceneeeeeneeeteneeteneeeteaeeeteeaeeesenesessnneeeseneeetsnneeeneeeesenaes 51 Merrolah Iv www metrolab com lt GETTING STARTED lt 1 Introduction The Three axis Hall Magnetometer THM1176 is used to measure the magnetic field strength Its unique extraordinarily compact design allows it to be used as a portable instrument or directly connected to a PC The THM1176 provides the total field no matter the orientation of the probe which greatly facilitates many measurement tasks such as field mapping For an overview of the Instrument e capabilities please see Chapter 3 Overview Chapter 7 Technical Specifications and Chapter 8 Sensor Technical Description The THM1176 resembles other standard USB devices it and its software are easy to install and easy to use Nonetheless please take a moment to browse through Chapter 2 Quick Start Guide and Chapter 4 User Interface Pay particular attention to the cautionary notes in Chapter 2 Quick Start Guide It is easy to develop custom software for the THM1176 especially in LabVIEW Please see Chapter 5 Application Programming Interface Chapter 6 USB I
25. dswecasenessedudavsasbaansccnesk eucusendsuguuctideceueserseiesguvacdedanenneadedewenevads 48 9 Error e E 48 9 4 E r EMO EE 48 9 2 100 Command Ertonswesj act hihealie eae eee ine As He ee Rel eee 48 9 2 1 1022 SYMAX EE 48 9 2 2 104 Datla type OIF vsecerecscacestacevstenceexteeupestctetinstvadivanda tues cougettn dtecesovs dea tudcaeeatetar dns a aaae 48 9 2 3 115 Unexpected number Of parameters o eeeeceeeeeeeneeeteneeeeeeneeeteneeeesenesetenneeeseneeesenesenenneeeennes 48 922 4 123 ExPONne Nt Ee EE 48 922 5 151 Invalid String Cala EE 48 9 2 6 24 712 INVALIC OXPIOSSION EE 48 Merrolah III www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 9 3 2002 Tute IN TEE 49 9 39 1 221 Settings Eege Eege Ee eege EE anaes a AE aE 49 9 3 2 222 Data Out e 49 92373 225 OU OF MEMO iori a aa iaa os dE aaeain 49 9 4 300 Device Dependent Errors cccseceeesscceseeeeeeseeneeeneneeseseneeesaeeeeneaeeeeseneeseaeeeseaaeesesesenseeaeeneneeeenanes 49 9 4 1 363 Input buffer overun eneee 49 9 5 400 Query ED 50 Banten dese aaia E aE Aa AAE a Ea a O E aa EARE 50 9 5 2 e Mee e RRE RE 50 9 5 3 420 Query UNTERMINATED AA 50 9 5 4 440 Query UNTERMINATED after indefinite response 50 9 6 100 Instrument Dependent Command Errors ececeeesseeeeeneeeeeneeeeeneeeeeeneeeseeeeeeeaeesesaeeeseneeeeneneteneaes 50 9 6 1 101 I v lid VAIUG INS cc scciescseasnccccsesisce
26. e Size Digits Timeout ms Dup VISA session E E Sleep Select o o o Temp Timstamp 1 5 1000 Output x Y Z sl o Vo co000 EN j 9 00000 SH 0 00000 j Temperature Timestamp Digits o Error in no error status code di Jio y source l o Performs a measurement and parses the result Function In Selects the function to be performed MEASure Abort any pending triggers and perform measurements using the default acquisition parameters o Continuous trigger initiation off o Trigger source immediate o Apply calibration correction READ Abort any pending triggers and perform a measurement with the existing parameters FETCh Fetch data values acquired during last MEASure READ or INITiate Note The following actions invalidate previously acquired data o Reset o Continuous trigger initiation o Changing trigger parameters Sleep In If set the THM1176 will switch off the analog power after executing the command The THM1176 microcontroller also puts itself to sleep whenever it can but this happens automatically The resulting power savings are significant in battery powered applications Switching the analog power back on happens automatically before the next measurement note however that this takes approximately 100 ms Select In Select the values to be returned 0 X 1 Y 2 Z 3 Temperature 4 Timestamp Size In Number o
27. e Start Settings System Power Advanced page For this reason automatic sleep is disabled for the THM1176 Failure to follow these instructions will hang the measurement software in such a way that it cannot be stopped The only way to reactivate it is to reset the PDA by using the stylus to press the Soft reset button on the bottom of the PDA gt When exposed to a strong magnetic field the touch screen of the PDA will cease to function The power of the PDA must be cycled to restore full operation Merrolah 4 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 2 4 NOTES e The orientation of the axes relative to the sensor are as follows X Y e A recording file is an ASCII file organized into seven columns delimited by tabs o B total field o Bx By Bz X Y and Z components of field respectively o Units as selected when the data was recorded o Temperature the units are arbitrary i e not calibrated in degrees o Time stamp a 16 hex digit tick count where 1 tick 10 ms Every line is terminated by an end of line marker carriage return for Windows and Windows Mobile e Some PDA USB Host adaptor cables may not have a power connector Plug the AC adaptor into the DC in connector on the PDA instead e Ifyou plug the THM1176 into the PDA before the PDA completes its initial boot procedure you will see an Unidentified USB Device dia
28. e plastics entirely This results in a package only 2 3 mm thick Note however that the sensor wires are very delicate and can easily be broken DESKTOP KIT A complete magnetic field measurement kit The desktop kit includes everything except the computer the THM11 76 instrument calibrated from 0 to 3 T a zero Gauss chamber the National Instruments VISA runtime library and USBTMC driver turn key measurement software all the LabVIEW source code software licenses from Metrolab as well as National Instruments and this manual Measurements out of the box Install the VISA Runtime library and measurement software plug in the THM1176 and go The software allows you to display B Bx By and B either numerically or on a strip chart display set the units in which the results are displayed capture the maximum field value hold freeze a given measurement record data to a file and display a recorded file A Setup page allows you to choose amongst multiple THM1176 plugged into your PC set the measurement range or auto range select the measurement update rate select the number of acquisitions to be averaged for each displayed value set the THM1176 into power saving mode and initiate the user offset correction procedure Customized measurement software A powerful and easy to use LabVIEW Application Programming Interface API allows instrumentation system programmers to readily integrate the THM1176 into their measurement s
29. ed_value gt lt digits gt Return z component of flux Merrolah 37 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description MMEMory Read the THM1176 FLASH memory CATalog Read the file directory Returns Total bytes used Total bytes available File entries consisting of File name File type File size DATA lt filename gt Read the contents of the given file Command Parameters Description READ Abort any pending triggers and perform a measurement with the existing parameters Note cannot be used when TRIGger SOURce BUS SCALar Perform a single measurement Set the range for the expected value if provided use the previously selected range if not Return at least the requested number of significant digits FLUX lt expected_value gt min 0T max 20T def 0T lt digits gt min 1 max 5 def 3 IX BCEE value gt digits gt Return x component of flux lt expected value gt Return y component of flux HE e r gits gt SE value gt lt digits gt L Return z component of flux ARRay Perform a series of lt size gt measurements The other parameters are as for MEASure SCALar FLUX lt size gt min 1 ma
30. eld applications you will need the LabVIEW PDA Module from National Instruments www ni com Note that for licensing reasons the handheld versions of the API and UIF are only available to customers who purchased the handheld option 5 1 GENERAL The VIs in the programming API have two standard inputs e VISA session VISA resource name that specifies the instrument with which we want to communicate Set to the Instr class e Error in a standard error structure describing errors in previous VIs and two standard outputs e Dup VISA session a copy of VISA session e Error out describes errors that occurred in this VI or in previous ones As is common practice in LabVIEW the connectors for these standard inputs and outputs are located on the four corners of the VI s icon In a sequence of VIs the standard outputs of each VI are wired to the standard inputs of the succeeding VI as shown in the example below INITiate 7 This chaining serves two purposes it forces the VIs to be executed in the given order and it stops the execution of the chain if an error occurs In fact each VI checks whether its Error in input Merrolah 17 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA indicates that an error has occurred in a previous VI if so instead of its normal function it simply copies Error in to Error out In this fashion the Error out at t
31. ensitivity to planar Hall effect Merrolah 47 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 4 REFERENCE 9 Error Codes Error codes returned by the USB Interface are numbered according to the SCPI standard Sections 21 8 9 through 21 8 16 of Volume 2 of the SCPI manual Command Reference provide a generic description of all possible error codes In general the codes are between 800 and 300 This chapter describes only the error codes produced by the THM1176 and the circumstances that might produce each error In addition to the SCPI errors the THM1176 Application Programming Interface might produce additional errors in the range of 1073807360 to 1073807192 and 1073676290 to 1073676457 OxBFFFOOxx and 3FFFOOxx the former are errors and the latter are warnings These are VISA error codes and are not documented here See the LabVIEW on line help under VISA Error Codes or right click on the error indicator and select Explain error 9 1 0 NO ERROR Zero indicates no error 9 2 100 COMMAND ERRORS 9 2 1 102 Syntax error The command header did not match any of the known commands 9 2 2 104 Data type error A parameter within the command was of a type invalid for the command 9 2 3 115 Unexpected number of parameters The wrong number of parameters was given in the command 9 2 4 123 Exponent too large The command contai
32. ent software Modify the THM1176 measurement software or write a measurement system from scratch using the LabVIEW development system Merrolah 2 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 2 2 USING THE THM1176 WITH THE HANDHELD 2 2 1 Handheld Assembly e Install the battery in the PDA and charge it You can charge the battery in three ways o Lift the rubber cover covering the DC in connector on the bottom left side of the PDA and plug in the AC adaptor o Plug the short USB Host adaptor cable into the USB synchronization cable connector on the bottom of the PDA and plug the AC adaptor into the power connector on the USB Host adaptor cable o Plug the 1 2 m long USB Device adaptor cable plugs into the USB synchronization cable connector on the bottom of the PDA and plug the other end of the adaptor cable into the USB port of a PC e Turn on the PDA by 1 sliding the Hold switch on the left side of the PDA to the unlocked position up and 2 pressing the Power button on the top right hand corner of the front of the PDA e If you have not done so yet plug the short USB Host adaptor cable into the USB synchronization cable connector on the bottom of the PDA e Plug the THM1176 into the USB Host adaptor cable 2 2 2 Handheld Measurement e Press the big button on the right side of the PDA to start the measurement software Alternatively you can use t
33. essage AVailable response ready to be read 5 ESB Event Summary Bit 6 RQS ReQuest for Service 7 OSB Operation Summary Bit o Standard Event Status Register Latches certain standardized events The THM1176 uses the following bits Merrolalh 30 www metrolab com THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Bit Name Description 0 Operation Complete OPC has flagged operation complete 2 Query Error Error in preceding query 3 Device Dependent Errors specific to the THM11 76 including Error internal errors 4 Execution Error Error detected during command execution 5 Command Error Error in preceding command 7 Power On THM1176 has been powered up o OPERation Status Captures conditions which are part of the instrument s normal operation The THM1176 uses the following bits Bit Name Description 0 CALibrating Measuring zero offset 2 RANGing Changing range 4 MEASuring Measuring magnetic field strength 5 Waiting for TRIGger Waiting for trigger o QUEStionable Status Indicates conditions that may reduce the quality of the measurement The THM1176 sets the following bits Bit Name Description 5 FREQuency The acquisition buffer has been overrun which makes the frequency questionable 9 The measurement was over range which makes the amplitude questionable
34. f measurements Digits In Number of significant digits in measurement result Output Out The returned measurement values if any The form of X Y Z depends on the settings of FORMat CALibration STATe and UNIT CAL STAT ON FORM ASC selected units CAL STAT ON FORMSINT pT CAL STAT OFF raw ADC values The temperature value is in arbitrary units The time stamp is a 64 bit integer returned as a string because LabVIEW does not support such a format Can be parsed as two 32 bit unsigned integers if need be If FORM ASC and Select includes X Y or Z the Digits output returns the number of digits behind the decimal point to allow displays to be correctly formatted Merrolah 20 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 5 7 MMEMORY MMEMory Read the THM1176 FLASH memory VISA session Dup VISA session What In What to read xi E CATalog a list of files stored in FLASH komans DATA the contents of the file chosen CATalog Filename In The filename for What DATA Filename Error in no error status code Ao d source Error out Response Out The returned list of filenames or file contents 5 8 READ VISA resource name 7 byte count fi error in no error status code dup VISA resource name read buffer return count 0 error out status code Performs
35. h 40 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA After an INITiate command with TRIGger SOURce BUS the THM1176 expects TRIGger COUNt triggers before resuming normal operation During this interval the following commands are illegal CALibration INITiate DIAGnostic UPGRade INITiate FETCh INITiate IMMediate ALL SENSe FLUX RANGe UPPer SENSe FLUX RANGe AUTo The following commands are legal but cause an ABORt and therefore terminate the acquisition sequence RST ABORt MEASure READ INITiate CONTinuous is only useful for TRIGger SOURce TIMer to avoid losing triggers Using the OPC command you can generate a ReQuest for Service RQS when a measurement or any other action is complete Set bit 0 of the Standard Event Enable register and the ESB Event Summary Bit in the Status Enable register Now the execution of an OPC command will generate an RQS Alternatively set bit 4 MAV Message AVailable in the Status Enable register and append the OPC command to the previous commands This will generate an RQS because OPC places a 1 on the output If you program the instrument to generate an RQS it is very important to Enable Service Requests on the host This posts a read on the appropriate USB endpoint the Interrupt endpoint In the USB protocol the host initiates all transfers so if the host has not posted a read the instrument canno
36. hat the power saver requires an update rate of at least 0 1 s see the description of the Sleep control in Section 5 6 for more details Straighten Control enable or disable the sensor rotational correction The sensor IC may be slightly twisted with respect to the ceramic base of the sensor package This misalignment is measured and recorded during calibration If it is important that the measurements be correctly aligned relative to the ceramic base generally for a fixed installation this option should be enabled Note not on the handheld version Offset ZERO Control Initiates the User Offset Correction procedure see Sections 2 1 2 and 3 1 Merrolah 14 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 4 1 OFFSET ZERO DIALOG This dialog is displayed while the User Offset Compensation procedure is in progress Keep the probe in the Zero Gauss Chamber as long as it is displayed WvietrolaD Instruments 3 Note due to an as yet unidentified bug in the PDA version of the software this dialog sometimes only appears briefly at the very end of the calibration procedure During the calibration procedure the ZERO button will be darkened 4 1 INITIALIZATION FAILURE DIALOG Indicates that the measurement software did not find the THM1176 Usually you simply need to plug in the THM1176 The THM1176 should start up and be
37. he THM1176 icon in the Programs folder of the Start menu e Press the big button on the left side of the PDA to bring up the virtual keyboard Press it again to hide the keyboard The software will hide the keyboard automatically within twenty seconds e Be sure to stop the measurement software using the Stop button on the Setup screen before turning off the PDA see the note below e Manipulate the probe and check the offset as described in Section 2 1 2 2 2 3 Handheld Software Development e Insert the installation CD and open the PDA directory e Copy the LabVIEW folder to your hard drive The API subfolder contains the Application Programming Interface see 5 Application Programming Interface The UIF folder contains the source code of the THM1176 measurement software e Modify the THM1176 measurement software or write a measurement system from scratch using the LabVIEW development system with the LabVIEW PDA Module Merrolah 3 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 2 3 PRECAUTIONS gt High magnetic field gradients as found for example around an MRI or NMR spectroscopy magnet will subject the THM1176 USB connector and the PDA to strong forces To prevent injury from flying objects or whiplashing cables be sure to hold these components securely when you are around a strong magnet NOTICE Do not bend the probe cable sha
38. he end of the chain indicates the precise error that caused the rest of the chain not to execute The sections below describe each Virtual Instrument VI with its inputs and outputs The standard inputs and outputs described above are not documented for each VI 5 2 CALIBRATION CALibration VISA session Dup VISA session E Function State INITiate P Error in no error status code Collects all functions dealing with the device calibration Function In Function to perform INITiate initiate offset correction procedure in zero gauss chamber ZERO Restore factory offset correction STATe query Get current calibration state STATe ON Apply temperature amp gain 5 calibration source STATe OFF Do not apply temperature amp gain calibration State Out Displays the current calibration state for a STATe query 5 3 CLOSE Close Closes the current session VISA session E Error in no error Error out statuscode status code aD a Merrolah 18 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 5 4 FORMAT Sets the output format for measurements or gets the current setting The output format can be text ASCii or binary INTeger The output format is further affected by the CALibration STATe and UNIT settings FORMat FORM ASC CAL STAT ON Meas
39. hes x component of flux The following special parameters are recognized MINimum MAXimum DEFault Numeric parameters usually require units Analogously the values returned by queries contain units as specified by the UNIT command In addition some units can have prefixes U micro 10 M milli 10 K kilo 10 MA mega 10 The THM1176 recognizes the following units Magnetic field strength T M Tesla default MAHZP Megahertz proton GAUSS K Gauss Other S M U Seconds The following tables list the legal commands for the THM1176 in alphabetical order Merrolah 34 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description ABORt Reset the trigger system Aborts acquisition in progress Disables trigger Disables continuous trigger Command Parameters Description CALibration Initiate the offset correction INITiate S procedure in zero gauss chamber ma Restore factory offset correction STATe Query calibration state eqns E EE Set calibration state whether or not temperature and gain calibration is applied ON by default Command Parameters Description DIAGnostic Initiate a firmware upgrade The UPGRade THM1176 will disconnect from the INITiate USB bus and reconnect as a DFU Device Firmware Upgrade device with the follow
40. ia oa a EE e Fascha a E 8 Brow Handheld EE 9 3 6 Calibration Maintenance Repair and Warrenty ccccccceeceeceeeeeeeeeeeeeeeeeeeeeeeeeseeenaeeeeeeeeenaeeeeeseeeaeees 9 USING THE THMI176 iirin enaena a aa aa tus ceeactedennccdeedccecualecdaesusacdes seaweed tdenaudendided iaiia 11 de User INGO ACC sna S 11 Gi Numere DISplay EE 11 Ge Lo DIE o EE 12 e ISDS TEE 12 e Ee BETEN 14 dal OffSet ZERO IDialOG s sciccicecececsncbedgeepeesegd headtsneshctcenseconeide cba dvacOssudes pasudeidangestaldacdestects aidosnaciingscasuecsdeeesse 15 4 1 Initialization Failure Dialog 15 4 2 Overrange Error Dialog viei2 ccsecceteciecevegs ncnsin cs eebsteciesuceess denne aans os aaia a aodai dani oaia a aaae Siadar E Ea EEEa 16 PROGRAMMING THE THM1176 2 ccecceeeeeeeeeeeeeeeeeeeeee see eeee ee EEEEEE ENEE EEEEEE ENEE ENN 17 5 Application Programming Interface sccccceseeeeeeeeseeeeeeeeeseeeneeeeeseceneeeesneeneeeenseeeeeeeeseesenens 17 SEET UE 17 5225 CAL IDFA ON EE 18 E Ee EE 18 Merrolah II www metrolab com Copyright 2008 Metrolab Instruments SA THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA BA E IT 19 Ha E EE 19 5 6 MEAGure FETOh READ ESEESE SEENEENEEESEESESNEAEESEAN EEES EES EEEn EEEE nEn 20 E Olli 21 5 8 EE 21 9 ROSGL coches Secessiue gh E E E ed 21 p VO REVISION QUO EE 22 D11 DONE EE 22 Coed eae el E 22 E EE 23 DNA SUPA MMS EE 23 ENT ie EE 24 SECO UNII E
41. ing alternate settings CODE DATA RESERVED and HWINFO The DIAGnostic UPGRade INITiate command is intended for use by the manufacturer only It can cause your THM1176 to become nonoperational 1 See Universal Serial Bus Device Class Specification for Device Firmware Upgrade Version 1 1 Aug 5 2004 available from http www usb org developers devclass_docs DFU_1 1 pdf Merrolah 35 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description FETCH SCALar Fetch data values acquired during last MEASure READ or INITiate The following actions invalidate previously acquired data Reset Continuous trigger initiation and Changing trigger parameters lt digits gt Fetch x component of flux lt digits gt min 1 max 5 def 3 lt digits gt Fetch y component of flux lt digits gt min 1 max 5 def 3 lt digits gt Fetch z component of flux lt digits gt min 1 max 5 def 3 TIMestamp Fetch time stamp Returns 8 byte hexadecimal tick counter where 1 tick 10 ms EMPerature Fetch temperature Returns unsigned integer between 0 and 64K with arbitrary units ARRay Fetch values acquired during the last MEASure ARRay or READ ARRay lt size gt must be no greater than the acquisition size If FORMat is ASCii returns a co
42. l Not used in THM1176 Generation STATus CLS Clear status STB SRE Read and enable bits in Status Byte USBTMC USB488 USBTMC USB488 Request service from host ESR ESE Read and enable bits in Standard Event Status Register OPC WA Detect and wait for operation complete STATus Read and enable bits in OPERation and QUEStionable registers SYSTem ERRor Query error queue SYSTem USBTMC USB488 Clear input and output buffers USBTMC USB488 Remote local control ineffective since THM1176 has no local controls RST Perform reset TST Perform self test not supported by THM1176 METROO 28 www metrolab com THM1176 User s Manual v 1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Functional Block Command s Function IDN Return Instrument ID SYSTem VERSion Return SCPI version SYSTem HELP Provide command help SYSTem SLEEp Power down analog subsystem MMEMory MMEMory Manipulate FLASH memory files DIAGnostic DIAGnostic Initiate firmware upgrade 6 3 IEEE 488 2 SCPI STATUS REGISTERS IEEE 488 2 compliant instruments have at least two registers the Status Byte and the Standard Event Status Register SCPI adds the Operation Status Register Questionable Status Register and Error Event Queue The diagram below taken from the SCPI standard provides a good summary This section describes how the THM1176 uses these status registers Me
43. log Simply unplug the THM1176 cancel the dialog and plug the THM1176 back in when you see the PDA s Today screen e If you are using a Windows PC the ActiveSync software included on the SoMo 650 Companion CD will simplify file transfers between the THM1176 and your PC e The PDA Reinstall directory on the THM1176 installation CD contains the files and instructions required to reinstall the PDA software Merrolah 5 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA USING THE THM1176 4 4 3 Overview This chapter provides a quick overview of what you can do with the THM1176 Additional details are provided in subsequent chapters 3 1 MEASUREMENT Three axes Simultaneous measurement of all three axes of the magnetic field provides the total field no matter the orientation of the probe Microscopic field sensitive volume A sensor size of only 150 x 150 x 10 um provides excellent localization and a self consistent measurement of the three axes even in highly inhomogeneous fields Field strengths up to 20 T Four measurement ranges 100 mT 500 mT 3 T and 20 T allow measuring even very strong fields The range may be selected manually or the instrument can auto range Bandwidth of DC to 1 kHz The 1 kHz bandwidth allows measuring AC fields generated for example by transformers and motors Immediate trigger mode Three trigger
44. mma separated list of values FLUX 2X lt size gt lt digits gt Fetch x component of flux lt size gt min 1 max 2048 def 1 lt digits gt min 1 max 5 def 3 lt size gt lt digits gt Fetch y component of flux lt size gt min 1 max 2048 def 1 lt digits gt min 1 max 5 def 3 lt size gt lt digits gt Fetch z component of flux lt size gt min 1 max 2048 def 1 lt digits gt min 1 max 5 def 3 Command Parameters Description FORMat DATA Query data output format DATA ASCii INTeger Set format for returned flux data ASCii by default INTeger returns an IEEE488 2 definite length block consisting of an 8 byte header of the form 6nnnnnn and followed by nnnnnn bytes of binary data The data consists of a 32 bit big endian signed integer for each flux value containing the 16 bit big endian raw measurement value if calibration correction is disabled or the flux value in uT otherwise Merrolah 36 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description INITiate IMMediate ALL Enable the trigger where the trigger source trigger count and trigger period are set with TRIGger commands CONTinuous Query continuous trigger state CONTinuous lt boolean gt Set co
45. modes allow the acquisition procedure to be fine tuned for the measurement Immediate trigger mode the default starts an acquisition sequence immediately upon receiving the measurement command To support noise reduction by averaging up to 2048 samples can be acquired at a high rate approximately 12 kSamples sec Timed trigger mode A timed trigger is suitable for measuring AC signals Corresponding to the 1 kHz bandwidth the maximum sample rate is 2048 samples sec with a continuous readout in blocks of 2048 samples every second Bus triggered mode The USB bus trigger command can be used to synchronize the acquisition with external events The instrument allows up to about 400 bus triggers per second Accuracy and resolution Three axis calibration provides an accuracy of 1 of the measured value At the bottom end of each range the accuracy is limited by the resolution approximately 0 1 of full scale see the specifications for details Note that the 20 T range is only calibrated up to 3 T The resolution can be improved by averaging an average of N measurements will improve the resolution by a factor of approximately VN Merrolah 6 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 3 2 User offset correction To guarantee the specified accuracy the measurement offset should be checked before each measurement sequence using the zero gauss chamber supplied
46. nal Computer PC or a Personal Digital Assistant PDA via a Universal Serial Bus USB interface If you use the LabVIEW driver or programming API it is generally not necessary to refer to the information in this chapter You may however want to write a LabVIEW program optimized for your application bypassing or complementing the general purpose API provided by Metrolab This chapter will provide you with the information necessary to do so The THM1176 was designed to plug and play with a Virtual Instrument Software Architecture VISA compliant software library in particular the NI VISA library from National Instruments see htip www ni com If you are not using NI VISA you will probably need information that is not provided in this chapter e USB 2 0 See Universal Serial Bus Specification Revision 2 0 April 27 2000 available from http www usb org developers docs usb 20 092407 zip e USBTMC and USBTMC USB488 See Universal Serial Bus Test and Measurement Class Specification USBTMC Revision 1 0 April 14 2003 and Universal Serial Bus Test and Measurement Class Subclass USB488 Specification USBTMC USB488 Revision 1 0 April 14 2003 available from http www usb org developers devclass_docs USBTMC 1 006a zip e SCPI See Standard Commands for Programmable Instruments SCPI VERSION 1999 0 May 1999 available from http www scpiconsortium org SCPI 99 pdf e IEEE 488 2 See IEEE Sta
47. ndard Codes Formats Protocols and Common Commands for Use With IEEE Std 488 1 1987 IEEE Standard Digital Interface for Programmable Instrumentation IEEE Std 488 2 1992 available from http standards ieee org reading ieee std_public description im 488 2 1992 desc html e VISA See VPP 4 3 The VISA Library VPP 4 3 2 VISA Implementation Specification for Textual Languages VPP 4 3 3 VISA Implementation Specification for the G Language VPP 4 3 4 VISA Implementation Specification for COM all Revision 2 2 March 17 2000 by the VXI plug amp play Systems Alliance available from http www ivifoundation org Downloads Specifications htm Merrolah 26 www metrolab com THM1176 User s Manual 6 2 SCPI INSTRUMENT MODEL v1 1 r10 07 08 Copyright 2008 Metrolab Instruments SA The THM1176 complies with the Standard Commands for Programmable instruments SCPI standard SCPI uses a standard instrument model to organize the command structure The diagram below shows the subsystems concerning the signal flow Measurement Function Signal a INPut SENSe CALC __ FORMat gt Routing ulate 4 f a p TRIGger MEMory Sg H igna CALC lt Routing lt OUTput SOURce K FORMat Signal Generation The following table provides a summa
48. ns a numeric parameter that was too large to be stored internally This occurs if the value has an exponent greater than 43 9 2 5 151 Invalid string data The parameters in the command contain an unmatched single or double quote 9 2 6 171 Invalid expression The parameters in the command contain an unmatched bracket Standard Commands for Programmable Instruments see Section 6 1 for the complete reference Merrolah 48 www metrolab com THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 9 3 200 EXECUTION ERRORS 9 3 1 291 Settings conflict Indicates that a legal program data element was parsed but could not be executed due to the current device state e Starting an acquisition when trigger is not enabled e Auto ranging is enabled but trigger source is not IMMediate e Sending a bus trigger when trigger is not enabled when the trigger source is not BUS or when the expected number of triggers have already been received e Received a CALibration INITiate DIAGnostic UPGRade FETCh INITiate MMediate ALL SENSe_FLUX_RANGe_UPPer or SENSe_FLUX_RANGe_AUTo command when triggers were enabled in BUS trigger mode e Received an INITiate CONTinuous command when not in TIMer trigger mode e Received READ command when in BUS triggered mode or e Received SYSTem SLEEp when triggers were enabled 9 3 2 222 Data out of range Indicates that a legal program data element was parsed
49. nterface and Chapter 9 Error Codes Finally keep your THM1176 up to date by downloading the latest firmware software and manual We post all updates on our website The easiest way to be notified of updates is to sign up for our electronic newsletter published twice a year please see the Newsletter Subscription page of the News section of Metrolab s website Section 3 6 provides some additional details We hope the THM1176 will help you perform your magnetic field measurements easily and accurately If you have problems and your reseller cannot help you further the Metrolab team is ready to help Even if you don t have problems we are always interested in knowing more about how our instruments are used Feel free to contact us at any time at contacts metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA GETTING STARTED 2 Quick Start Guide 2 1 2 1 1 2 1 2 2 1 3 USING THE THM1176 WITH A PC PC Software Installation Insert the installation CD and open the PC directory Install the VISA Runtime Library by running visaXXXruntime exe XXX indicates the version number Note that if needed you can download and install a more recent version of the VISA Runtime Library from the National Instruments website http www ni com Also note that you may already have NI VISA installed for example if you use LabVIEW or software that came with your oscilloscope Install
50. ntinuous trigger state where the trigger is automatically re enabled after each acquisition OFF by default Only allowed and only useful if TRIGger SOURce is TIMer Command Parameters Description MEASure Abort any pending triggers and perform measurements using the default acquisition parameters Continuous trigger initiation off Trigger source immediate Apply calibration correction SCALar Perform a single measurement Set the range for the expected value if provided auto range if not Return at least the requested number of significant FLUX lt expected_value gt min 0T max 20T def 0T lt digits gt min 1 max 5 def 3 2X lt expected_value gt lt digits gt Return x component of flux lt expected_value gt Return y component of flux 22 lt digits gt lt expected_value gt lt digits gt r Return z component of flux ARRay Perform a series of lt size gt measurements The other parameters are as for MEASure SCALar FLUX lt size gt min 1 max 2048 def 1 lt expected_value gt min 0T max 20T def 0T lt digits gt min 1 max 5 def 3 2X lt size gt lt expected_value gt lt digits gt Return x component of flux lt size gt lt expected_value gt lt digits gt Return y component of flux lt size gt lt expect
51. opposite directions resulting in a Hall voltage on the remaining terminals A team at the EPFL in Switzerland led by Dr Popovic Popovic applied this technique to design a 3 axis sensor sensor on an IC called the MAG3D The array of Hall Hall elements measures 150 x 150 x 10 um a million fold reduction in active volume compared to a conventional approach This allows precise position determination as well as consistent measurements of all three components even in highly inhomogeneous fields But MAGS3D contains much more than the Hall elements To build a Hall magnetometer we need to supply a current and measure a voltage By increasing the current and or amplifying the voltage Bonding connectighs Driving part Sensing part d Read out electronics and buffers electronics one can increase the sensitivity All this is done on the IC the external electronics only supplies 5V power and two digital lines to select one of four ranges 1 5 3 or 20 T This represents a tremendous simplification of the magnetometer as a whole Image courtesy of Senis GmbH But there s more All Hall magnetometers suffer from measurement offset in other words the instrument measures a non zero result even in a zero field What s more this offset varies with time and temperature One should calibrate the instrument in a zero gauss chamber before each use and the instrument has to continuously correct the me
52. ote The touch screen of the PDA will cease to function The power of the PDA must be cycled to restore full operation Merrolah 44 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 7 7 WARRANTY CALIBRATION CERTIFICATION AND MAINTENANCE Warranty 2 years Recommended calibration interval 18 months 3 Axis Hall Probe only Certification CE approved Maintenance Firmware upgradable by end user Merrolalh 45 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA e REFERENCE 8 Sensor Technical Description This chapter is adapted from an article by Philip Keller of Metrolab in the June July 2008 issue of Magnetics Business amp Technology http www MagneticsMagazine com To measure the total field we need three orthogonally oriented Hall TE eee sensors Typically three individual sensors are glued into a cube roughly five to ten millimeters on a side But now there is another way a single IC containing one conventional planar Hall element and two sets of vertical Hall elements JH The vertical elements can be thought of as plates of N type silicon inserted vertically into a P type substrate If a current is injected into the center terminal and extracted from the two end terminals the currents in the two halves of the plate flow in opposite
53. pacer and do not over tighten the screw Weight With 2 m cable 150g With 5 m cable 280 g Size of field sensitive point 150 um x 150 um x 10 um Sensor dimensions and location of field sensitive point marks the sensitive point field 165 mm KE gt i vezign nsnm h L3 mm 7 5 DESKTOP K IT Contents 3 Axis Hall Probe with 3 or 6 meter cable Zero Gauss Chamber Full range calibration on 0 1 0 5 and 3 T ranges 20 T range to 3 T CD with acquisition software for PC Windows XP Vista LabVIEW source code for all PC software and user s manual Software license from Metrolab including free updates Software functions Numerical and graphical display of data including total field Range and units selection Hold and Maximum Record to file and recall file Record file format ASCII tab delimited compatible with Handheld file format Merrolah 43 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 7 6 HANDHELD KIT Contents Contents of the desktop kit plus Industrial quality PDA Heavy duty Li lon battery 2600 mAh plus spare 1200 mAh AC adaptor charger 100 240 VAC 50 60 Hz 500 mA with wall socket adaptor plugs for Europe UK USA Australia USB Host adaptor cable to connect PDA to THM1176 USB Device adaptor cable
54. recognized within approximately ten seconds Merrolah 15 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 4 2 OVERRANGE ERROR DIALOG Indicates that the measured field was higher than the maximum for the selected range On the Setup page select a higher range or Auto Merrolah 16 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 4 PROGRAMMING THE THM1176 oe 5 Application Programming Interface The LabVIEW programming Application Programming Interface API for the THM1176 allows users to easily write instrument control programs Most but not all of the functions provided by the Instrument e USB interface are made available through this API Some logically related functions in the USB interface have been regrouped in the API A standard low level I O utility function guarantees robust communications with the THM1176 and allows programmers to easily add any command or combination of commands that they require Both the LabVIEW API and User Interface UIF are included in source code format on the CD that came with your THM1176 If upgrades become available you will be able to download them from the Metrolab website download metrolab com If you purchased the THM11 76 with the handheld option you will also receive the handheld version of the API and UIF source code To build your own handh
55. rned Units out Out If Query is true returns the currently selected units Merrolah 24 www metrolab com THM1176 User s Manual 5 17 WRITE AND READ v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Write amp Read VISA session Command E IDN Dup VISA session Response Error description Timeout ms Error in no error 3000 status code Error out Write a command to the instrument and read the response Nearly all the commands issued by the instrument API pass through this VI It is highly recommended that any custom commands also use this utility Vi Command In Command to write Timeout In The delay between the write and when the read should occur This gives devices time to respond Num bytes In Size of transfer buffer If the response is longer than this value the response will be read in multiple transactions Response Out Response returned by instrument when command was executed Error description Out List of error descriptions returned by instrument s Dn status code Num bytes 3 L l 41073676290 1024 KG source 154 Enable vent in Write nd Read vi Merrolalh 25 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA PROGRAMMING THE THM1176 6 USB Interface 6 1 GENERAL The THM1176 communicates with a host either a Perso
56. rply This is a special cable with individually shielded signal wires in order to minimize induction artifacts Sharp bends break the shielding For details about using the PDA please refer to the SoMo 650 Quick Start Guide flyer and SoMo 650 User s Guide file SoMo 650_UG pdf on the SoMo 650 Companion CD These include important safety instructions gt When removing the adaptor cables from the synchronization cable connector on the bottom of the PDA take care to squeeze the two release buttons on the side of the connector Else you will destroy the cable locking mechanism and in the future the connector can accidentally slip loose Due to a bug in the VISA library the PDA version of the THM1176 software cannot handle disconnecting and reconnecting the THM1176 This has two implications o You must stop the measurement software before unplugging the THM1176 There is a Stop button on the Setup screen for this purpose Note that in Windows Mobile closing the window does not stop the application You can see the running applications using Start Settings System Memory gt Running Programs o You must also stop the measurement software before placing the PDA in sleep mode The PDA can be placed in sleep mode manually by sliding the Hold switch on the left side of the PDA to the locked position down The PDA can also be placed in sleep mode automatically by the power saver see th
57. rrolalh 29 www metrolab com THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA QUEStionable Status VOLTage CURRent TIME POWer TEMPerature FREQuency PHASe MODulation CALIbration Available to designer Available to designer Available to designer Available to designer INSTrument Summary Command Warning NOT USED Error Event Queue 0 1 2 3 4 5 6 7 8 9 OPERation CALIbrating SETTing RANGing SWEeping MEASuring Waiting for TRIGger Summary Waiting for ARM Summary CORRecting Available to designer Available to designer Available to designer Available to designer Available to designer INSTrument Summary PROGram Running NOT USED KEE KREE Standard Event Status Register Available to designer Available to designer Operation Complete Error Event Queue or Available to designer Request Control Query Error Device Dependent Error Execution Error Command Error User Request Power On MAV d OD Ob G hM sa CO Summary of IEEE 488 2 Status Structure Registers The use of Bit 15 is not allowed since some controllers may have difficulty reading a 16 bit unsigned integer The value of this bit shall always be 0 o Status Byte Contains a 1 byte status summary The THM1176 uses the following bits Bit Name Description 2 EAV Error AVailable in Error Event Queue 3 QSB Questionable Summary Bit 4 MAV M
58. ry of the THM1176 capabilities organized according to the SCPI instrument model The supported commands include IEEE 488 2 Common Commands start with as well as SCPI commands Many commands have additional options or query forms to return the currently set value see later sections for details In addition to ASCII commands the THM1176 also supports certain USBTMC USB488 controls also noted in this table Functional Block Command s Function Measurement MEASure Measure with standard settings Equivalent to Funcion RST READ READ Measure with custom settings Equivalent to ABORTt INITiate FETCh FETCh Fetch measurement results previously acquired with MEASure READ or INITiate Merrolah 27 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Functional Block Command s Function e Signal Not used in THM1176 Routing e INPut S Not used in THM1176 e SENSe SENGSe Select range and auto ranging e CALCulate CALibration Compute and apply calibration factors FORMat FORMat Set output format UNIT Set output units TRiGger TRG Generate a trigger USBTMC USB488 INITiate Enable triggers ABORt Abort triggers TRIGger Select trigger source and characteristics MEMory S Not used in THM1176 Signa
59. t complete its RQS transfer This will block the Interrupt endpoint and any other commands using this endpoint notably the USBTMC USB488 Read Status Byte function will fail Be sure to check the status after every command The Standard Event OPERation and QUEStionable Status registers provide a general idea of what went wrong and the status message on the Error Event Queue retrieved by SYSTem ERRor provides a detailed diagnostic See Chapter 9 Error Codes for the exact interpretation of these error messages It may be convenient to set up the Enable bits to generate a ReQuest for Service RQS when an error is encountered Merrolah 41 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA 4 REFERENCE 7 Technical Specifications 7 1 MEASUREMENT Ranges 100 mT 500 mT 3T 20T automatic or manual ranging Data output By By Bz ASCII or binary single point or array calibrated or not Temperature uncalibrated Time stamp 10ms resolution Units T mT G KG MHz p NMR frequency of proton Sample rate Immediate trigger default Approx 12 kHz free running until internal buffer is full Timed trigger 0 36 Hz to 2 048 kHz timer resolution of at least 0 24 continuous read out in blocks of 2048 samples Bus trigger via USB Up to approx 400 Hz until internal buffer is full Notes 1 sample B By B2
60. the capabilities of an IEEE488 instrument on the USB bus IEEE488 derived from HPIB GPIB is the world s most widely used instrumentation protocol IEEE488 compliance allows any VISA library Virtual Instrument Software Architecture to control every aspect of the instrument The software supplied with the instruments includes the National Instruments VISA Runtime library Standardized instrument command protocol The SCPI standard Standard Commands for Programmable Instruments is the standard developed and used by large instrumentation manufacturers such as Tektronix and HP Agilent and provides a programming interface familiar to many instrumentation system programmers Merrolah 7 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 3 3 PROBE MECHANICAL DESIGN Protection for the sensor The sensor is a sensitive electronic component With the cap in place on the probe the sensor is well protected from the bumps and scrapes of normal use Small gaps To measure in a small gap the probe cap can be removed reducing the thickness to only 4 1 mm Stationary installation Removing the cap also reveals a mounting point that allows the probe to be permanently mounted or attached to a scanning arm The exact position of the field sensitive point can be determined by optical sighting Even smaller If needed the sensor can be reduced to its minimum size by removing the prob
61. trying to read a response without having sent a complete query 9 5 4 440 Query UNTERMINATED after indefinite response Indicates that a query was received in the same program message after a query requesting an indefinite response was executed On the THM1176 the only command returning an indefinite response Arbitrary ASCII Response Data is IDN 9 6 100 INSTRUMENT DEPENDENT COMMAND ERRORS 9 6 1 101 Invalid value in list One or more values in a numeric list parameter are invalid e g floating point when not allowed 9 6 2 103 Wrong units for parameter A parameter within the command has the wrong type of units for the command 9 7 200 INSTRUMENT DEPENDENT EXECUTION ERRORS 9 7 1 200 Software Error The firmware has encountered an unexpected error e the User Offset Zero file has been corrupted e the ADC driver returned an unknown error code e the command parser or dispatcher returned an unknown error code e encountered an error formatting a result e could not open one of the data files file e unable to perform reset e encountered an unknown choice for character data Merrolah 50 www metrolab com THM1176 User s Manual v7 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA e encountered something other than a value MINimum MAXimum or DEFault for a numeric parameter e encountered something other than a Boolean or DEFault for a Boolean parameter or e encountered an unknown parameter type
62. u can write your own portable magnetic measurement application or to modify the standard one The only thing you need is the LabVIEW PDA Module an add on to LabVIEW CALIBRATION MAINTENANCE REPAIR AND WARRENTY Calibration procedure The THM1176 can only be calibrated by Metrolab This is because special high field magnets tooling and software are required to calibrate all three axes at multiple temperatures and write the results to flash memory Recommended calibration interval All customers are of course free to fix the intervals at which they send the THM1176 back for calibration within the context of their quality assurance policy Metrolab s recommendation is to send the instrument back for calibration at least once every eighteen months Recommended calibration dates To minimize costs Metrolab establishes a limited number of dates in the year when batches of THM1176 magnetometers will be calibrated To avoid substantial extra charges you should ship the unit back to Metrolab in order to coincide with one of these dates Please see the Metrolab website or contact Metrolab to receive a list of these recommended dates Merrolah 9 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA e Upgrades Via its website Metrolab will make available improvements and bug fixes for the THM1176 firmware software and manual Customers will be notified about available upgrades via
63. urement in text selected units vitae REES FORM ASC CAL STAT OFF id ER Fi Measurement in text raw ADC values Function Response FORMSINT CAL STAT ON Query Measurement in 32 bit binary uT error in no error error out FORMSINT CAL STAT OFF status code d Jio 2 source Measurement in 32 bit binary raw ADC values Note that MEASure_FETCh_READ parses binary as well as text output Function In Function to be performed Query Get current setting ASCii Select ASCII output format INTeger Select binary output format Response Out Returns current setting for a Query 5 5 INITIALIZE Initialize Initialize the THM1176 LabVIEW API ID Query In Use the IDN command to verify that Instrument descriptor VISA session the instrument identifies itself as a THM1176 z zj Reset In Reset the instrument after opening a ID Query eee session to it Gp A THM1176 Out Instrument identified itself as Reset THM1176 Description THM1176 Only valid if ID Query is selected L gt THM1176 Description Out Instrument description returned by IDN command Only valid when ID Query is selected Error in no error Error out status code s Ze Merrolah 19 www metrolab com THM1176 User s Manual 5 6 MEASURE_FETCH_READ v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA MEASure_FETCh_READ VISA session Ze D Function MEASur
64. ux DEFault measurements are returned if FORMat is ASCii T by default 6 7 PROGRAMMING HINTS Note that National Instruments Measurement amp Automation Explorer part of the LabVIEW package provides a very useful tool to explore the command set Select the THM1176 under System Peripherals amp Interfaces USB Devices and click the Open VISA Test Panel icon This opens a window from which you can try all functions available through NI VISA Here are a few notes on how the command set is intended to be used For simple measurements with the standard settings in single channel mode use the MEASure command MEASure ARRay returns a time series Use the UNIT and FORMat commands to change the format in which the results are returned Use the READ commands for measurements with non standard trigger parameters or to return raw measurement data without applying calibration corrections As with MEASure READ ARRay returns a time series Use the FETCh command to retrieve all data corresponding to a preceding MEASure READ or INITiate command or FETCh ARRay for the data corresponding to a MEASure ARRay READ ARRay or INITiate with TRIGger COUNt gt 1 Try to build a CALibration sequence with a zero gauss chamber into the beginning of any lengthy measurement sequence The THM1176 is designed to have very low offset and offset drift but as with any Hall device these remain a significant source of error Merrola
65. x 2048 def 1 lt expected_value gt min 0T max 20T def 0T lt digits gt min 1 max 5 def 3 2X lt size gt lt expected_value gt lt digits gt Return x component of flux lt size gt lt expected_value gt lt digits gt Return y component of flux lt size gt lt expected_value gt lt digits gt Return z component of flux Merrolah 38 www metrolab com THM1176 User s Manual v1 1 r1 0 07 08 Copyright 2008 Metrolab Instruments SA Command Parameters Description SENSe FLUX RANGe UPPer 0 1 0 5 3 20 T Set the range 20 T by default UPPer Query the current range setting ere Seed eons Set the range to provide the largest dynamic range ON by default Note auto ranging can only be used with TRIGger SOURce IMMediate Command Parameters Description STATus OPERation Query set OPERATION register sets EVENt Read and clear operation event register CONDition Read operation condition register ENABle Query enable register ENABle lt numeric_value gt Set enable register 0 by default QUEStionable Query set QUEStionable register sets EVENt Read and clear operation event register
66. ystem This manual provides complete documentation of the API and command interface The source code for the turnkey measurement software is also provided Merrolah 8 www metrolab com THM1176 User s Manual v7 1 61 0 07 08 Copyright 2008 Metrolab Instruments SA 3 5 HANDHELD KIT Everything the PC software can do in a portable instrument A compact lightweight and rugged handheld computer Personal Digital Assistant or PDA allows you to take measurements in the field The PDA software has the same functionality interface and file recording format as the PC software Even under the heaviest load conditions the built in battery lasts over six hours and the backup battery provides another few hours Includes the entire desktop kit You can choose to connect the THM1176 either to the PDA included in the handheld kit or to a PC In the second scenario you can do everything you can do with the desktop kit A full featured PDA The PDA has many features that can be combined in creative ways to enhance your use of the magnetometer For example a THM1176 recording file can be inspected in Word Mobile or imported manipulated and plotted in Excel Mobile Alternatively you can transfer the files to a PC using the included USB Device cable via a CompactFlash or SDIO flash card or via the 802 11 or Bluetooth wireless networks Customized handheld applications As with the PC software you have all the source code so yo

Three-axis Hall Magnetometer THM1176 User`s Manual

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