User's Manual - METROLAB Instruments
Contents
1. The chosen operation remains after switching off the THM 7025 5 5 MAP The MAP n Command sends to RS 232c the displayed value where n 1 at each press of button lt HOLD gt the displayed value is sent to RS 232c n 0 release MAP function Note Thanks to the RS 232c interface the mapping of a field is very convenient The THM 7025 is positioned where a measurement of the field has to be taken When the user is pressing the button lt HOLD gt the displayed value is sent to the computer thus allowing easy acquisition of magnetic field values METROLAB Instruments SA THM 7025 User s Manual 5 6 STZ Set To Zero The STZ n Command deals with the sensor offsets where n 1 measures and memorizes the User s Offset on the three axis This Command has the same result as by pressing down the buttons lt ZERO gt and lt HOLD gt See section 4 6 page 11 WARNING to measure the User s Offset the user has to place the probe in the zero field chamber which itself must be in a magnetic environment below 0 15 mT 1 5 Gauss or about 3 time the Earth magnetic field strength n 0 reverts to System Offset This Command has the same result as by pressing down the buttons lt ZERO gt and lt ON OFF gt See section 4 6 page 11 The STZ Command returns 0 if THM 7025 is being used with System Offset or returns 7 if it is being used with User s Offset 5 7 BZA B on single Axis This command allows the user to2. ete al la ls La os Reserved 0 Local User s Hold Single Range Range or LockOut Offset is Axis h 1 1 used Bit 7 Reserved Bit 6 O or 1 Can be 0 or 1 Information used at the factory only test and diagnostic purposes Bit 5 Local LockOut This bit is set to 1 when the keyboard is locked It is cleared to 0 when it is in operation Bit 4 User s Offset This bit is set to 1 when the THM 7025 is used with the User s Offset It is cleared to O when it is used with the System Offset Bit 3 Hold This bit is set to 1 when the display is held It is cleared to O when the display is running Bit 2 Single axis This bit is set to 1 when the THM 7025 is used in single axis mode It is cleared to O when the 3 axis mode is activated Bits 1 and 0 Ranges These bit indicate the range Combination of 0 and 0 cannot occur METROLAB Instruments SA 17 THM 7025 User s Manual 18 5 11 OFF auto OFF The OFF n Command controls the automatic switch Off function n 0 mode auto OFF is canceled The THM 7025 is On until it is switched Off by using the button lt ON OFF gt or the OFF 2 Command The display reads On for 0 4 sec n 1 mode auto OFF is enabled meaning that the THM 7025 will be automatically switched Off by itself after 3 minutes when unused The display reads OFF for 0 4 sec n 2 the THM 7025 is switched Off 5 12 BAT BATtery Level The BAT Command returns the current batte
3. gave the last syntax error Returns the THM 7025 firmware version Reset the THM 7025 Clear an error condition Lock Unlock the THM 7025 keyboard Returns the battery level in 1 10 Volt Reset or power on
4. messages They are displayed until the error condition is cleared mr 22 The range is overloaded the user can select the higher range if it is possible This is an error in reading or writing the parameters in the none volatile memory EEPROM This is a fatal error which cannot be cleared and the instrument needs to be repaired This error arises when there is a fault in the RS 232 communication or the reading of the keyboard It can be cleared by either pressing button lt ZERO gt or by using the command CLE This error occurs either during a User s Offset measurement when the residual magnetic field is too high to be nulled or during regular measurements when the internal memory is saturated However the latter should never occur in normal operation This error can be cleared by either pressing button lt ZERO gt or by using the CLE Command METROLAB Instruments SA THM 7025 User s Manual 7 APPENDIX B WARRANTY METROLAB Instruments SA warrants each instrument of its manufacture to be free from defects in material and workmanship Our obligation under this warranty is limited to servicing or adjusting free of charge any THM 7025 system returned to our factory for that purpose This warranty covers the THM 7025 and its accessories which within one year after delivery to the original purchaser shall be returned with transportation charges prepaid by the original pu
5. of iron Therefore the plug in power supply should never by exposed to magnetic field stronger than 0 1 Tesla METROLAB Instrument SA cannot be hold responsible for any accident occurred by the misuse of the THM 7025 or by none respect of the present warning METROLAB Instruments SA 7 THM 7025 User s Manual 8 METROLAB Instruments SA THM 7025 User s Manual 4 PRINCIPLE OF OPERATIONS 4 1 Operating procedure e Slide the battery door at the back of the unit Install the 9V battery and replace the battery door e Plug the sensor into the connector at the top of the unit e Turnon the THM 7025 by pressing the ON OFF switch for at least 1 sec The THM 7025 is being manually operated by 5 switches Section 4 2 DISPLAY mT 3 AXIS HALL _ TESLAMETER Section 4 5 ES Section 4 3 Section 4 4 e Section 4 6 Figure 4 keyboard view 4 2 ON OFF On and Off switch Press once for at least 1 sec instrument is On Press again instrument is Off If the lt ON OFF gt switch of the THM 7025 is not being used or if no RS 232c command is sent the THM 7025 switches off automatically after 3 minutes To disable the automatic switch Off press the button lt HOLD gt hold it and then press lt ON OFF gt The display shows On for about 0 4s to indicate that the instruments is now On until you turn it Off by using the lt ON OFF gt button METROLAB Instruments SA 9 THM 7025 User s Manual 10 T
6. 4 LEO Local Lockout A nn Mets nd elfe Panne 18 DAS ERR ERRON neta le cit 18 5 16 CL CLear Emor satin Man nee dan de ete 19 6 APPENDIX A THM 7025 S display daa 21 7 APPENDIX B WARRANTY a as pda oia 23 8 APPENDIX C Summary of the RS 232c commands 24 METROLAB Instruments SA I THM 7025 User s Manual Il METROLAB Instruments SA THM 7025 User s Manual Conventions This manual uses the following conventions lt HOLD gt name of a keyboard button ENQ a RS 232c command BAT an indication in the display 1 a parameter or option 200 a string of characters returned by the THM 7025 METROLAB Instruments SA 1 THM 7025 User s Manual 2 METROLAB Instruments SA THM 7025 User s Manual 1 GENERAL DESCRIPTION The METROLAB 3 axis Hall Teslameter THM 7025 is an instrument using HALL elements to measure magnetic fields The main feature of the THM 7025 is the simultaneous measurement of the 3 axis X Y Z which are set at 90 angle allowing a direct measurement of the magnetic field intensity without a particular orientation of the sensor isotropic The THM 7025 calculates and displays the modulus of the magnetic field as per the equation B Bx By Bz The magnetic field value is displayed in mT on a 3 digits Liquid Crystal Display The THM 7025 and its probe provide a portable magnetic field measuring system The keyboard gives the ope
7. M ET ROLA B Instruments SA THM 7025 3 AXIS HALL MAGNETOMETER User s Manual Version 2 01 Revision 1 4 September 1997 110 ch du Pont du Centenaire CH 1228 GENEVA SWITZERLAND TEL 41 22 884 33 11 FAX 41 22 884 33 10 e mail contacts metrolab ch THM 7025 User s Manual INDEX COMO nid desde nent Reese ee een ren ne een 1 1 GENERAL DESCRIPTION iii ia 3 2 SPECIFICATO N consi A tt ries Ae rollito ete ets se 5 O eas sie eta cuca resncentevauesieaa haul E E a E O eE e R A 7 4 PRINCIPLE OF QORERA TIONS ses nn tilda 9 4 1 Operating procedure etene reenter nentrn rneer rennene ennnen neneman ennnen 9 A 1 O r e a ata Tne 9 ASS RANGE E EE E E E E ek tee Renee 10 44 Bz BOn Z axiS eeni een ennemie eee eee 10 4 TA A D PP SE EE e eden ac 11 4 60 ZERO ss RI he RO ec Masel Rae A DA A net eed hs Re 11 5 INTERFACE RS 232c COMMANDS tune ane nt tada 13 Os INTRODUCTION See ne ns nn ne eRe POSTE Gr At out 13 5 2 ENQ ENQuire displayed value 13 DO INRANGE en den aan hater bat thus cate Ans etienne 14 34 HED HOLD ii cas 14 PIN feces PR nea eek ad tzendta ue tate mses race ating 14 56 SIZ Set FO ZO coisa ne RNA n e na DR niet 15 5 7 BZA B n Single AXIS ste ica 15 5 8 VER firmware VERSION estirar RS ce hast yeaa 15 5 9 5 T1 STatus register iii a A di 15 DOSE A STAUS register 2 AT 17 ds 1s OFF AO OFF irern de nn a a e ee aia pets 18 5 12 BAT BA Mery Level viii 18 Ds 13 RSTIRESeT A ne A nn td A 18 5 1
8. e computer with the following RS 232c parameters 9600 bauds 8 bits no parity 1 stop bit No XON OFF The control of the THM 7025 through the serial interface is made with a set of commands Every command consist of a string of ASCII characters using the following syntax a root of 3 mnemonic characters then one or zero parameters then the characters carriage return ASCII 13 and Line feed ASCII 10 The root and the parameter are separated by a comma Note the characters carriage return line feed are mandatory for any command as well as they are returned at the end of any string of characters sent by the THM 7025 However to clarify the text they have been omitted in the command description Some commands are read only ex ENQ or write only ex CLE The others are read and write commands They are used to set a parameter or an option In write mode these commands include the parameter ex RNG 2 and in read mode these commands have no parameter ex RNG and the present parameter value is returned by the THM 7025 The set of commands is described in the following sections 5 2 ENQ ENQuire displayed value The ENQ Command returns the value of the magnetic field The returned string of characters corresponds to the display This command will return the field value presently displayed If the THM 7025 is overloaded the ENQ Command will return O L If the ENQ Command is sent wh
9. em Offset If the user of the THM 7025 needs to readjust the Offsets he has to place the probe in the zero field chamber then press button lt ZERO gt hold it and press button lt HOLD gt The Offsets is then measured and memorized The new set of Offsets remains after switching off the THM 7025 Even if the THM 7025 is in single axis mode the offset measurement is performed on the 3 axis Press lt ZERO gt hold it press lt HOLD gt User s Offset The User s Offsets is recalled on the keyboard by METROLAB Instruments SA 11 THM 7025 User s Manual Warning because the THM 7025 is an instrument measuring 3 axis the User s Offset cannot be used to offset the display when the sensor is in a given magnetic field i e relative measurements otherwise the measurements will be dependent on the sensor orientation C To restore the System Offset defined at the factory the user will press lt ZERO gt hold the button and press lt ON OFF gt This action resets the default parameters including that the Z axis will be the default axis when pressing the lt Bz gt button Press lt ZERO gt hold it press lt ON OFF gt System Offset The System Offset is recalled on the keyboard by 12 METROLAB Instruments SA THM 7025 User s Manual 5 INTERFACE RS 232c COMMANDS 5 1 INTRODUCTION Ensure the instrument is Off before connecting the supplied RS 232c cable from the THM 7025 to the serial port of the computer Set th
10. en the THM 7025 is changing the range of measurement display reads the returned string of characters will be The ENQ n Command gives the value of the magnetic field of the individual axis where n 1 for X Axis n 2 for Y Axis n 3 for Z Axis Note if the THM 7025 is in single axis mode ENQ will return the magnetic field value of this axis only Whereas ENQ n will return 0 if n refers to one of the none selected axis METROLAB Instruments SA 13 THM 7025 User s Manual 14 5 3 RNG RaNGe The RNG n Command modifies the ranges of measurement where n 1 or 20 sets 19 99 mT range n 2 or 200 sets 199 9 mT range n 3 or 2000 sets 1999 mT range n 0 sets in autoranging mode The RNG Command returns the current status of range in a string of characters which has the following meaning 0 for the autoranging mode 20 for the 19 99 mT range 200 for the 199 9 mT range 2000 for the 1999 mT range 5 4 HLD HoLD The HLD n Command holds or releases the display where display is held n 1 n 0 display is running The HLD Command returns the current status of Hold mode The HLD n Command alternates normal and toggle operation of the button where 2 button lt HOLD gt is in toggle operation 3 n n 3 button lt HOLD gt is in normal operation see section 4 5 at page 11 on how to use button lt HOLD gt Note The selected operation normal or toggle is memorised
11. field is too high to be nulled The error 3 can be cleared by either pressing button lt ZERO gt or by using the CLE Command METROLAB Instruments SA 19 THM 7025 User s Manual 20 METROLAB Instruments SA THM 7025 User s Manual 6 APPENDIX A THM 7025 s display Dass is The sign is used only t when the when the THM 7025 is in measuremen single axis mode is held The BAT symbol indicates that the battery must be replaced Magnetic field value displayed with 3 digits Figure 5 Messages displayed A Status messages They are displayed during half second cr This message indicates a restart of the measurement process T This happen when the THM 7025 is turned On when it is reset or a E when the single 3 axis mode is changed ve This message is displayed when the automatic Off function is LITT disabled ME This message is displayed when the automatic Off function is bee D again enabled D L ing i 7 TE Autoranging is selected The range is moving to the higher range Taking 0 4 sec METROLAB Instruments SA 21 THM 7025 User s Manual n Li nn LILI nnn LILI LS n E LL a At The range 1999 mT is selected The range 199 9 mT is selected The range 19 99 mT is selected The THM 7025 returns to the System Offset The User s Offset is being measured and memorized B Error
12. his function is recalled on the keyboard by The OFF command can cancel or enable the automatic switch Off See section 5 11 page 18 Also when the battery is too low the display indicates BAT and a few minutes later the THM 7025 switches Off by itself 4 3 RANGE The values of measurement are displayed in three ranges 1 19 99 mT 2 199 9 mT 3 1999 mT When the THM 7025 is switched On it is set on autoranging mode and it displays the measurement in the most appropriate range By pressing lt RANGE gt it switches from Autoranging to 1999 by second pressing to 199 9 by third pressing to 19 99 and then switches back to autoranging mode Before displaying the value of the magnetic field the THM 7025 displays the selected range for a half second Refer to the following chart Pressure on Range of Range indication in lt RANGE gt measurement the display When switched On Autoranging io oe ol 4 4 Bz B on Z axis The lt Bz gt button toggles between 3 and single axis measurements To distinguish between these two modes the sign or is displayed with the magnetic field value in single axis mode Otherwise no sign is displayed By default the chosen axis is Z The access to another axis is possible via the RS 232c command BZA see section 5 7 page 15 When switched On 3 Axis measurement Press once measurement of a single axis Z display of or Press again comes back to 3 Axis measuremen
13. rator complete control over the different measurement modes as well as over the zeroing of the probe All the functions of the THM 7025 controls and measurements can be accessible to a computer supplied by the user via a RS 232c serial interface METROLAB Instruments SA 3 THM 7025 User s Manual Figure 1 The THM 7025 Location of the 3 axis hall Figure 2 The 3 axis sensor and the axis direction Figure 3 Hall sensor position 4 METROLAB Instruments SA 2 SPECIFICATIONS Ranges Resolution Accuracy Temperature coefficient of the gain Display Update rate Measurement mode Operating temperature magnetic field Storage temperature Size main unit sensor Weight Interface Battery THM 7025 User s Manual 19 99 mT 199 9 mT 1999 mT DC full scale ranges Automatic or manual ranging 0 01 mT 0 1mT 1mT 2 of reading or 3 digits 0 05 C from 25 C 3 Y Digits LCD mTesla units 0 4 sec or hold 3 axis or one axis i e Bz or Bx By 0 C to 40 C Main unit only 0 1T 1 5T when battery is removed 20 C to 60 C 160 x 80 x 30 mm 12 x 12 x 100 mm 250 g RS 232c 9 Volt type SLM9V Lithium 22h duration display reads BAT when battery is low If connected with RS 232c to computer duration of battery is much less A THM 7025 system is supplied in its own hard side plastic carry case with one piece of each follo
14. rchaser and which upon examination shall disclose to our satisfaction to be defective If it is determined that the defect has been caused by misuse or abnormal conditions of operation repairs will be billed at cost after submitting an estimate to the purchaser METROLAB Instruments SA reserves the right to make changes in design at any time without incurring any obligations to install same changes on units previously purchased This warranty is expressly in lieu of all other obligations or liabilities on the part of METROLAB Instruments SA and METROLAB Instruments SA neither assumes nor authorizes any other person to assume for them any other liability in connection with the sales of the THM 7025 DAMAGE IN SHIPMENT The instrument should be examined and tested as soon as it is received If it does not operate properly or is damaged in any way immediately file a claim with the carrier The claim agent will provide report forms A copy of the completed form should be forwarded to us We will then make necessary arrangements for repair or replacement METROLAB Instruments SA 23 8 APPENDIX C Summary of the RS 232c commands Measured value in mT Measured value in mT ona single axis Select the measurement range 0 3 20 200 2000 Select the single 3 axis mode 0 3 Hold the measurement 0 1 Set to zero User s Offset System Offset 0 1 Disable Enable the auto Off 0 2 Status Register 1 Status Register 2 Returns the command which
15. ry level in 1 10 of Volts Example 92 indicates 9 2 V 5 13 RST ReSeT The RST Command resets the THM 7025 The THM 7025 returns to the same status as when it has been switched On 5 14 LLO Local LockOut The LLO n Command blocks or releases the keyboard It presents a safety if the user does not want to loose the parameters which he has modified by touching accidentally the keyboard of the unit 1 the keyboard is locked O the keyboard is in operation n n 5 15 ERR ERRor The ERR Command returns the first 3 digits of the last command which gave a syntax error The syntax error is indicated by bit 1 of status register 1 METROLAB Instruments SA THM 7025 User s Manual 5 16 CLE CLear Error The CLE Command clears an eventual error i e when the display reads Er 2 or Er 3 Errors description If a fault is detected the Display or the returned string of characters of the ENQ command indicates Er n where n 1 This is an error in reading or writing the parameters in the none volatile memory EEPROM This is a fatal error which cannot be cleared and the instrument needs to be repaired n 2 This error arises when there is a fault in the RS 232c communication or the reading of the keyboard This error can be cleared by either pressing button lt ZERO gt or by using the CLE Command n 3 This error occurs either during a User s Offset measurement when the residual magnetic
16. select any of the three single axis or the 3 axis mode The BZA n Command sets the Axis mode where for the X axis for the Y axis for the Z axis for the 3 axis mode SENS D 35 5 3 ou ou ou Note by pressing the lt Bz gt button the display indicates the magnetic field measured with the last single axis selected by the BZA Command The BZA Command returns the current status of the axis mode 5 8 VER firmware VERsion The VER Command returns the firmware version in the following string of characters METROLAB SA THM 7025 Ver X XX 5 9 ST1 STatus register 1 The ST1 Command returns the Status Register 1 METROLAB Instruments SA 15 THM 7025 User s Manual The Status Register 1 is returned in a string of 8 ASCII characters 0 or 1 followed by CR LF the first character received is the most significant bit bit 7 The ST1 n Command clears the bits of the Status Register 1 Where n is a decimal value from 0 to 255 which allows to write zeroes in Status Register 1 i e 0 clears all bits of the Status Register 1 255 doesn t clear any bits of the Status Register 1 9 clears all bits except the bits 3 and 0 of the Status Register 1 Meaning of the status register 1 las ls sl al Reset or EEPROM Battery Overload Command power on R W low or Com Error Error Bit 7 reset or power on This bit is set to 1 at power on or by a reset of the instrument using the RST Command Bi
17. t METROLAB Instruments SA THM 7025 User s Manual 4 5 HOLD As long as the button lt HOLD gt is pressed down the display of the measured value is held The sign 4 comes in the display By releasing lt HOLD gt the THM 7025 continues its measurement and gives new values This is the normal operation of the button When switched On running mode Press displayed value is held display of a Release running mode If user prefers to handle the button lt HOLD gt in the toggle way he can do so via an RS 232c interface Command see section 5 4 page 14 This is the toggle operation of the button Button lt HOLD gt will be used as follows Press displayed value is held display of a Release displayed value is still held display of Press go back to running mode Release still in running mode Note when pressing the button lt HOLD gt holding it and then pressing lt ON OFF gt the automatic switch Off will be disabled see section 4 2 page 9 4 6 ZERO This button supplies three functions Clearing of an error User s Offset and System Offset A While using the THM 7025 an error may occur Display reads Er n where n indicates the error number error description list is in section 5 15 page 18 The button lt ZERO gt clears the error and its indication Press lt ZERO gt once clear the error B The offsets of the Hall sensors are calibrated at the factory They are called Syst
18. t 6 always 0 Bit 5 always 0 Bit 4 EEPROM Read Write error This bit is set to 1 to indicate that there is an error in reading or writing parameters in the none volatile memory EEPROM This is a fatal error which cannot be cleared The instrument needs to be repaired Bit 3 Battery low This bit is set to 1 to indicate that the battery level is too low and thus the battery needs to be changed The display reads BAT Bit 2 Overload This bit is set to 1 to indicate that the range is overloaded The display reads O L The user can select a higher range if it is possible Bit 1 Command or communication error This bit is set to 1 to indicate that the syntax of a command was wrong The last command which gave the error is returned by the ERR Command This bit is also set in case of an error in the communication with the RS 232c interface Bit 0 Data ready This bit is set to 1 to indicate that a value is available for reading The update interval is about 0 4 sec 16 METROLAB Instruments SA THM 7025 User s Manual 5 10 ST2 STatus register 2 The ST2 Command returns the Status Register 2 The Status Register 2 is returned in a string of 8 ASCII characters 0 or 1 followed by CR LF the first character is the most significant bit bit 7 The bit of the Status Register 2 indicate the state of the instrument at the moment of the reading They cannot be cleared by the user Meaning of the status register 2
19. wing item e Hand held instrument e 3 axis sensor model THS7025 10 with its 1 5 meters shielded cable e 9 Volt Lithium battery e 110V or 220V plug in power supply model HPS7025 10 e Zero field chamber model ZFC7025 16 e 3 meters serial interface cable with Sub D 9 poles IBM PC type connector model SC7025 13 e User s manual METROLAB Instruments SA THM 7025 User s Manual 6 METROLAB Instruments SA THM 7025 User s Manual 3 SAFETY The THM 7025 can measure magnetic field up to 2 Tesla We strongly WARN and URGE the user to take into consideration the effects of such strong magnetic fields The THM 7025 unit is powered by a 9 Volt battery which is partly made out of iron Meaning that strong mechanical forces are applied to the battery and therefore to the THM 7025 unit The main unit WITH THE BATTERY INSIDE should not be exposed to magnetic field stronger than 0 1 Tesla By neglecting this warning the THM 7025 might be pulled away from the hands user EVEN WHEN BATTERY IS REMOVED the main unit should not be exposed to magnetic fields stronger than 1 5 Tesla The operation and the accuracy of the THM 7025 cannot be guaranteed as long as it remains in the magnetic field Without excluding that permanent damage can occur to the instrument When battery is removed and the plug in power supply is being used be aware of the similar danger since the transformer of the power supply contains a mass
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