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DTM -151-G Manual
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8. 51 1 through S1 5 set the DTM address on the bus A binary code is used as shown in the table Address 31 all switches ON is illegal 51 6 enables dual primary addressing of the teslameter on the GPIB In this addressing mode the least significant bit of the device address is ignored so that the device is activated by two adjacent addresses 3 6 DTM 151 GPIB User s Manual 51 7 when ON makes the teslameter a talker only In this mode it sends on the bus every field reading made It does not respond to commands This mode is useful in systems without a controller where the teslameter readings are continuously sent to a listening device such as a printer 52 1 through 52 6 are set according to the GPIB system requirements 52 1 is normally ON which allows the teslameter to assert the SRQ line and the SRQ bit of the serial poll response However if the GPIB system controller routines are to run without interrupts S2 1 should be switched OFF thus disabling all SRQ action 52 2 controls the operation of the EOI bus management line Normally the switch is ON so EOI is asserted each time the teslameter sends a string terminator character on the bus indicating the end of a response With S2 2 OFF the teslameter does not assert the EOI line 52 3 selects the character sent as a string terminator With the switch OFF the terminator is the line feed character When the switch is ON carriage return is used 52 4 when ON introduce
9. TEO no address extension talker capability L4 listener basic listener unaddressed to listen if addressed to talk LEO address extension listener capability SR1 service request capability RLO remote local capability PP1 parallel poll capability configured by controller DC1 device clear capability DT1 device trigger capability CO no controller capability DTM 151 GPIB User s Manual 4 13 In general the teslameter may act as a listener to receive commands from a system controller and as a talker to send field readings and other responses to the controller and other listening devices in the bus system The teslameter may be set by means of an internal switch to act as a talker only See page 3 6 This mode is used in systems which have no system controller in which the teslameter continuously sends field readings on the bus to listener only devices for example printers terminals or the Group3 COM 488 IEEE 488 to Serial Adaptor which converts the bus traffic to serial data format The teslameter responds to the following command messages on the bus This is a subset of the complete repertoire of bus commands given earlier decimal value hex ASCII value character 01 SOH 04 EOT 05 ENQ 08 BS 11 DC1 14 DC4 15 NAK 18 CAN 19 EM 20 3E gt 40 5 5F underscore 60 6F 0 70 IEEE 488 mnemonic GTL SDC PPC GET LLO DCL PPU SPE SPD UNL UNT PPE PPD descri
10. 5 14 DTM 151 GPIB User s Manual GROUP3 TECHNOLOGY LTD LIMITED WARRANTY Group3 Technology Ltd hereinafter called the Company warrants instruments and other products of its manufacture to be free from defects in materials and workmanship that adversely affect the product s normal functioning under normal use and service for a period of one year from the date of shipment to the purchaser The obligation of this warranty shall be limited to repairing or replacing at the discretion of the Company and without charge any equipment which the Company agrees is defective as set out above within its warranty period The Company will reimburse lowest freight rate two way charges on any item returned to the Company s factory or any authorised distributor or service centre provided that prior written authorization for such return has been given by the Company This warranty shall not apply to any equipment which the Company determines to have become defective owing to mishandling improper installation alteration negligence inadequate maintenance incorrect use exposure to environmental conditions exceeding specifications or any other circumstance not generally acceptable for equipment of a similar type The Company reserves the right to make changes in design without incurring any obligation to modify previously manufactured units No other warranties are expressed or implied including but not limited to the implied warranties of me
11. ASCII To stop the talker being a talker the Untalk command is sent i e decimal 95 hex 5F ASCII 4 10 DTM 151 GPIB User s Manual Bus Management Lines ATN IFC REN EOI SRQ Attention asserted when the controller is sending commands Not asserted while data is on the bus Also used with EOI see EOI below Interface Clear when asserted by the controller all bus activity is unconditionally terminated and the System Controller regains active control if control has previously been passed to another controller Any talkers or listeners are unaddressed Remote Enable if asserted while a device listen address is on the bus then the device will go into its remote mode End Or Identify dual function 1 when output from a talker indicates the end of a multi byte message when asserted during transmission of the last byte 2 during parallel polling the controller asserts EOI and ATN simultaneously This causes each device which has been configured for parallel poll to place its status on the appropriate status line Service Request asserted by a device when it requires attention from the controller The controller responds by servicing the device in an appropriate way Often the service request is used to indicate that the device has data ready to be sent The controller is not obliged to respond to the service request but the device will hold the line asserted until it has been serviced Service Re
12. Commands Output responses 2 2 10 measurements per second Full scale change of displayed field reading settles to within resolution in less than 0 3 second filtering off see below Displays maximum field since mode entered or reset Peak hold is implemented digitally with zero sag or decay Displays time varying ac component of field frequency response 8 Hz to 3 kHz at 3dB points response time constant 0 2 seconds average responding reads rms value of sinusoidally varying field reading is not linearity or temperature corrected 7 character 7 segment alphanumeric display 8 back lit legends for 0 3 0 6 1 2 3 0 tesla range selected peak hold mode on digital filtering on tesla gauss field units magnetic field peak hold field ac field peak ac field field value filtering smoothes out small fluctuations in the reading large rapid field changes are not filtered internally switch selected 2 keys for range selection access to display modes zeroing field display peak hold reset serial option RS 232C and fiber optic parallel option IEEE 488 General Purpose Interface Bus ASCII input commands and output responses requests for field values setting and inspection of display and control modes field measurement triggering entry of numerical values setting units output data format and filter characteristics test commands field value in tesla or gauss followed by optional T or G and s
13. quickly the display shows Addr nn where nn is the address of the teslameter as set on switches S1 1 though S1 5 Press the mode key once again to cancel this display 4 6 DTM 151 GPIB User s Manual 4 5 USING THE IEEE 488 GPIB INTERFACE 4 5 1 General Purpose Interface Bus Overview The IEEE 488 standard describes a means of communication to and from programmable instruments through a standard bus and associated protocol called the General Purpose Interface Bus GPIB Any instrument manufactured to this specification will be able to communicate on the bus Up to 15 instruments may be connected on the bus at any one time and they are considered to be listeners able to receive data talkers able to transmit data or controllers able to control and configure the bus DEVICE A CONTROLLER ABLE TO TALK LISTEN AND CONTROL DEVICE B ONLY ABLE TO LISTEN DEVICE C DATA BYTE TRANSFER CONTROL ABLE TO TALK AND LISTEN GENERAL INTERFACE MANAGEMENT DEVICE D ONLY ABLE TO TALK DIO 1 8 DAV NRFD NDAC IFC SRQ REN EOI Fig 6 A Typical IEEE 488 System DTM 151 GPIB User s Manual 4 7 A typical IEEE 488 setup is shown in Fig 6 This system contains a controller and selection of talkers and listeners However a wide range of system complexity is possible from systems with just one talker only and one listener only and no controller to systems including several controllers linked with many talker lis
14. 1 650 802 8292 Fax 1 650 802 8298 Contact Brian Richter email brian gmw com website www gmw com VI Control Systems LabVIEW programming control systems 2173 Deer Trail Los Alamos NM 87544 Tel 505 662 1461 Fax 866 422 2931 Contact Neal Pederson email np vicontrols com website www vicontrols com Manufacturer Group3 Technology Ltd 2 Charann Place Avondale Auckland 1026 New Zealand P O Box 71 111 Rosebank Auckland 1348 New Zealand Tel 64 9 828 3358 Fax 64 9 828 3357 email info group3technology com website www group3technology com
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16. KITE DTM 151 DIGITAL TESLAMETER with IEEE 488 GPIB Interface USER S MANUAL For units supplied with software DTMS V6 0 amp V7 0 Distributed by GMW Associates 955 Industrial Road San Carlos CA 94070 USA Tel 1 650 802 8292 Fax 1 650 802 8298 Email sales gmw com Website http www gmw com Manufactured by Group3 Technology Ltd PO Box 71 111 Rosebank Auckland 1348 New Zealand Tel 1 650 802 8292 Fax 1 650 802 8298 Email info group3technology com Website http www group3technology com 13 July 2007 Group3 Technology Ltd 2 Charann Place Avondale Auckland 1026 P O Box 71 111 Rosebank Auckland 1348 New Zealand Phone 64 9 828 3358 Fax 64 9 828 3357 email info group3technology com web www group3technology com 82010180 Thank you for purchasing and using a Group3 digital teslameter We hope you will join the many hundreds of users worldwide who are enthusiastic about our products Group3 has been designing and building magnetic field measuring equipment since 1983 We are constantly upgrading our products and support documentation We welcome input from our customers so if there are aspects of the instrument which you particularly like or which you would like to see improved please contact your Group3 supplier see back page for a complete list or Group3 directly with your suggestions to info group3technology com The Group3 website www group3technology com conta
17. Probe calibration is verified at many field points and a printed calibration table is supplied with every probe AC mode measures and displays time varying fields between 8 Hz and 3000 Hz Front panel keys set the display to read the desired field range to read the peak value of the field using the peak hold function to show the ac field component and to display the field temperature DTM 151 GPIB User s Manual 1 1 Peak hold is implemented digitally has zero sag Digital filtering of the displayed field reading suppresses short term fluctuations The filtering characteristic is non linear small field variations within a narrow window centered on the currently displayed value are filtered large field changes are displayed immediately Filter window and time constant may be changed by remote command Filtering is controlled by an internal switch Two digital communication options either serial RS 232C and fiber optic or IEEE 488 General Purpose Interface Bus With the serial option a single teslameter may be connected to standard RS 232C equipment or up to 31 units may be interconnected on a Group3 Communication Loop G3CL and driven from computer or terminal Fiber optic ports duplicate functions of RS 232C signals for electrical noise immunity and voltage isolation Fiber optic links may be up to 60 meters in length using Hewlett Packard HFBR 3500 series fiber optic cables Use a Group3 fiber optic repeater to extend commu
18. adverse environmental conditions The plugpacks supplied with each teslameter should be plugged in to a clean mains power supply Noise on the mains will work its way through the transformers and disturb the teslameter Simple mains filters are readily available if there is only one mains supply for the whole machine Route the low voltage lead away from high current or high voltage wiring Ideally cut the low voltage lead to the minimum length required for the installation and re connect the plug to it Grounding the teslameter case The probe shield is terminated to the probe connector case which is then connected by the retaining screws to the teslameter chassis At this point the entire shield system is floating In some installations it is beneficial to have the system floating but most frequently it is sensible to have the shields grounded If the teslameter is panel mounted then the case is almost certainly electrically connected to the control rack and grounded that way However if the teslameter is a bench unit then the rubber and plastic feet on it will isolate the case If the case does need to be grounded then loosen one of the screws on the back panel and put a grounding lug under the head of the screw It is most convenient to use a 1 4inch 6 35mm quick connect tab The grounding wire can then be easily disconnected if the teslameter has to be moved Use a heavy gauge short wire to ground the unit to a substantial grounding p
19. defaults switch S2 8 should be switched ON then OFF while power is applied See Fig 3 and also page 3 7 When no probe is connected to the DTM the display reads noProbE 3 3 CONNECTING THE POWER SOURCE All teslameter versions except for the L option are supplied with a plug pack Connect the plug pack to a convenient ac power source first checking the voltage marked on the plug pack and insert the cable connector into the power receptacle on the DTM rear panel Instead of the plug pack the unit can be powered by any convenient source of ac or dc either polarity 9 to 15 volts capable of supplying 0 7A rms ac or 0 5A dc The cable connector required for power connection to the DTM is a standard coaxial plugpack connector with 2 1mm centre hole and is generally available from electronics suppliers For extra immunity to damage and operational disturbance caused by serious high voltage sparking near the teslameter the use of the Group3 model PS12D7 off line switch mode power supply and the Group3 ferrite kit part no 11000036 is recommended These accessories will greatly reduce the amount of electrical transient 3 2 DTM 151 GPIB User s Manual energy entering the teslameter The ferrite kit includes a suppressor which fits to the probe cable near the point of entry to the teslameter to reduce the effects of transients picked up on the probe cable For a full discussion of techniques to promote trouble free operation in electricall
20. or DPMs ferrite kit 11000036 for spark protection power supply PS12D7 for spark protection DTM 151 GPIB User s Manual 2 5 DTM 151 GPIB User s Manual 3 SETTING UP 3 1 INTRODUCTION This manual provides operating instructions for all members of the DTM 150 family of digital teslameters with IEEE 488 interfacing and their companion LPT 130 LPT 230 MPT 132 and MPT 230 series Hall probes For a summary of all current members of the product family see page 2 5 These instructions are written for a teslameter with front panel display and keys DTM 150 DG PG Users of teslameters without display keys should ignore sections of this manual referring to these features All other aspects of operation are identical Before using your teslameter for the first time please read through sections 3 2 3 3 4 1 4 2 and 4 3 of this manual This will give a quick introduction to basic operation of the instrument If you have a teslameter without display DTM 150 NG LG also read sections 3 4 3 5 and 4 5 If you have the panel mount version DTM 150 PG mounting instructions are to be found in section 3 8 For help regarding operation in electrically noisy areas see section 3 9 3 2 CONNECTING THE HALL PROBE Before handling the probe please read the following Group3 Hall probes are built to be as robust as possible for a small precision device However it is most important that certain precautions be taken when handling and installi
21. protected by installing an external fuse in the ac power feed Suggested fuse ratings are 200 mA for 115 volts or 100 mA for 208 and 230 volt operation CASE GND GND PWR PWR 11 LINK LINK E PWR 115V 208V 230V Fig 1 Power Input Connections of the L option DTM 151 GPIB User s Manual 3 3 When the unit is first powered up the display shows Group 3 for 2 seconds before field measurements appear If the Hall probe is not plugged in the field reading display is replaced with noProbE 3 4 GPIB CONNECTION Connection to the GPIB connector on the rear of the DTM is made using cables as specified in the IEEE 488 1978 standard document Briefly the cable has 24 conductors with an outer shield The connectors at each end are 24 way Amphenol 57 series or similar with piggyback receptacles to allow daisy chaining in multiple device systems The connectors are secured in the receptacles by a pair of captive locking screws with metric threads The total length of cable allowed in a system is 2 meters for each device on the bus or 20 meters maximum A system may be composed of up to 15 devices Table 1 is a listing of the GPIB connector pin assignments Fig 2 shows the connector pin location and signal names as viewed on the teslameter rear panel pin symbol description 1 DIO1 Data Input Output line 1 2 DIO2 Data Input Output line 2 3 DIO3 Data Input Output line 3 4 DIO4 Data Input Output line 4 5 EOI End Or Identif
22. this is to warn the user that the field reading will not be to full accuracy Over range The message o rAnGE appears when the DTM is displaying dc or ac field or is in peak hold if the field measurement exceeds the instrument s input capacity To clear the over range message select a higher range or reduce the magnetic field at the probe or both if necessary During over range all key operations are locked out except for range selection Overflow The message o FLo is displayed in dc or ac field modes or in peak hold mode if the computed value of the field reading exceeds the capacity of the display that is if the number to be displayed is outside the range 99999 9 In overflow the instrument is not over ranged but rather the computed reading is too large to be displayed However if over ranging occurs at the same time as overflow then the over range message is displayed preferentially The usual cause of overflow is a large calibration factor scale factor or offset entered through the GPIB port See section 4 5 Reset The message rESEt appears for 1 second when defaults are reloaded either by a CTRL X command or by switching S2 8 ON DTM 151 GPIB User s Manual 4 5 No Local Control The message noLOCAL appears if a key is pressed when local control is locked out by the SO1 command See Table 9 in section 4 5 Address setting display With the teslameter in dc field display mode when the MODE key is pressed twice very
23. using F sooner than 60msec after the V command or the old field value may be sent 4 7 3 When the V command is ignored The V command is ignored by teslameters which have not been initialized for triggering by the GV command The V command is ignored by teslameters which have been initialized for triggering if the command is received while the device is still in the process of making a measurement in response to a previous V command 4 7 4 Zeroing while in triggered mode If the teslameter is zeroed either with the keys or by remote command while in the triggered mode a new zero offset will be calculated and stored using the last field measurement made The effect of the zero operation will be reflected in the next field measurement when the V command is given To ensure the most accurate zero it is best to place the teslameter in continuous mode with filtering on allow time for the display to settle then give the zero command The unit will zero correctly in triggered mode if first the V command is given while the probe is in zero field with filtering off then the Z command or pressing both keys together will zero the instrument 4 22 DTM 151 GPIB User s Manual 5 TECHNICAL The schematics component overlays and parts lists of the four circuit boards in the DTM 151 GPIB interfacing teslameter and probe are provided for general reference It is not recommended that the user attempt repair or servicing because in many
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27. 949 v 0 85 5047 2 q d pq 88 05 91089 od Hue 3ubrei3s surd Aum 9c surd 2 3ueazno ubru ao3onpuy 28146 020 PTOAOL tenp renp egm gz edr4 J9p os 4934205 9 18315410 MOT JOVeTNSUT wugzKe SdTTO snd ebans Tque asny esoduind gTIPNI sAL peeds vo cvs SA 220242 06 29 pea we A008 7258 un 4Uu j AST ANOT uuG z xurx dea ANTO 213 T O0I32e 9 AOT 400022 xurx deo ouou AOS 40170 44 2 XO04to edeo Aere 40 deo ouou ANT O YUTA deo 40170 uoradraoseg NO x iO Oe DoD
28. ERATION Triggering allows one or more teslameters to make synchronized field measurements on demand The teslameter is set for triggered operation by entering the command GV This stops continuous sampling of the field value Once the GV command has been entered there are two ways of triggering a field measurement e send the IEEE 488 Group Execute Trigger GET command This invokes the device trigger capability of the teslameter s IEEE 488 interface and is implemented by placing the GET code decimal 8 on the data lines and asserting the ATN line e enter the command V as follows address as listeners all the teslameters which are to be triggered send the teslameter command V As with all other teslameter commands the V is sent as ASCII data on the bus without the ATN line asserted The two triggering methods produce identical results except that the GET command triggers all teslameters which have been set for triggering by GV while V triggers only those units which have been addressed to listen The new measurement will immediately appear on the teslameter display and can be read out via the bus by entering the F command Alternatively if the teslameter is set for continuous transmission with the SM1 command after being set for triggered operation then following V or GET the device will issue a service request if service request is enabled The device can then be parallel polled and the field value read wit
29. ame situation Allow the probe to stabilize thermally for a minute or two before zeroing A range is selected by pressing the RANGE key The four range indicators show the selected range The RANGE key selects the ranges in turn in the sequence 0 3 0 6 1 2 and 3 0 tesla If a single range probe is in use the RANGE key will have no effect The zeroing process is implemented by pressing and releasing both keys together Alternatively press and hold either key while pressing the other key twice momentarily The display will read ZEro for a moment indicating that zeroing has occurred The zeroing process should now be repeated for all the remaining ranges Press the RANGE key to select another range and zero this range by pressing both keys together as above After changing ranges wait 1 or 2 seconds before zeroing Continue until all the ranges have been zeroed DTM 151 GPIB User s Manual 4 1 zero the ac ranges first select the ac mode by pressing the MODE key once A will appear at the left of the main display Now perform the zeroing function on all ranges as described above Because the ac measurement circuitry has a 0 2 second time constant allow the display to settle after changing ranges before zeroing Return to normal dc field display by pressing the MODE key 4 times Once the zeroing process has been completed the internal processor will apply the appropriate correction to whichever range is selected It is recom
30. by V IC Inspect calibration factor returns calibration factor as mantissa and exponent ID Inspect digital filtering status returns 0 for OFF 1 for ON IG Inspect general function returns two letters D for dc field mode or A for ac mode followed by C for continuous or V for triggered measurements lJ Inspect filter factor returns filter factor as mantissa and exponent DTM 151 GPIB User s Manual 4 15 IL IN lO IR 17 Ln NH NN NT On RO R1 R2 R3 SCn SEO SE1 SFn 4 16 Inspect sampling interval returns interval in seconds between output field readings 0 implies readings sent at maximum rate Inspect scale factor returns current scale factor Inspect display mode returns H for hold display N for normal field display T for temperature display Inspect offset returns current value of offset Inspect range returns 0 for 0 3 tesla range 1 for 0 6 tesla range 2 for 1 2 tesla range 3 for 3 0 tesla range Inspect window returns current value of window within which digital filtering operates Inspect zero returns current zeroing offset added to field values Filter factor enters filter factor n Default n 41 n 0or 1 no filtering n 1 filtering more severe as n increases max 65534 0 n 1 reading overshoots Sampling interval enters interval between output field values Default n 0 every reading sent rate is 10 samples second n any integer time in s
31. cases replacing parts will affect the calibration of the instrument In case of trouble or malfunction we strongly recommend that the user first contact the local distributor or Group3 directly for advice as to the best procedure for addressing the problem Group3 may be contacted at the address below Group3 Technology Ltd Physical address 2 Charann Place Avondale Auckland 1026 New Zealand Postal address P O Box 71 111 Rosebank Auckland 1348 New Zealand Tel 64 9 828 3358 Fax 64 9 828 3357 email info group3technology com website http www qroup3technology com diagram page Display Board Schematic 5 2 Display Board Component Overlay 5 3 Display Board Parts List 5 3 Probe Plug Board Schematic 5 4 Probe Plug Board Component Overlay 5 5 Probe Plug Board Parts List 5 5 Processor Board Schematic 5 6 Processor Board Component Overlay 5 7 Processor Board Parts List 5 8 Analog Board Schematic 5 9 10 Analog Board Component Overlay 5 11 Analog Board Parts List 5 12 13 DTM 151 GPIB User s Manual 5 1 ON UOISIAM pog Aojdsig P31 9 uu KO 16 08 44898 KO K TIRE EI lt a O0tZ dW H AN 10 4 dSOH gn Sri 89 Sri 253 82 z J 15 00 83114 xot CH AS Sri 11919 1 lt 4 9 5
32. d communications according to system requirements To obtain access to the switches turn the DTM over and take off the bottom cover by loosening the single central screw Refer to Fig 3 for switch locations Switch functions are as follows S1 8 way DIP switch sets device address on GPIB sets talker only mode 52 8 DIP switch selects operation mode and communication options Detailed DIP switch settings are given in Table 2 below switch function switch OFF switch ON 51 1 set device address adds 0 to address adds 1 to address 51 2 set device address adds 0 to address adds 2 to address 51 3 set device address adds 0 to address adds 4 to address 51 4 set device address adds 0 to address adds 8 to address 51 5 set device address adds 0 to address adds 16 to address 51 6 dual primary addressing disable enable 51 7 talker only mode talker listener talker only 51 8 not used S2 1 service requests disabled enabled 52 2 operation EOI not asserted EOI asserted 52 3 line feed carriage return 52 4 double terminator disabled enabled 52 5 field units tesla gauss 52 6 units symbol no symbol symbol after data 52 7 digital filtering filtering OFF filtering ON 52 8 defaults no action defaults loaded factory setting Table 2 DIP Switch Functions The switches are read by the processor once per second so the effects of changed settings can be observed in real time
33. ding as zero for selected range only The ranges are individually zeroed Default sets zeroing offset to zero returns a 16 bit binary number representing the states of the 16 DIP switches 0 OFF 1 ON once the command has been given changing the switches does not alter the teslameter operating mode until some other command is sent restarts operating software as if teslameter had been freshly powered up Reload defaults all default values reinstated Message RESET is sent Note SFn STn SWAn SWEn SWZn modes are cancelled by GPIB commands SDC and DCL see Table 6 page 4 14 End of Table 7 DTM 151 GPIB User s Manual 4 17 4 5 4 GPIB Messages The following error messages are transmitted under the circumstances described INVALID COMMAND ENTRY the command entered did not comply with Table 7 NUMBER TOO BIG the number entered in a command was too big POSITIVE NUMBER REQUIRED erroneous entry of minus sign DIVIDE BY ZERO acommand entered a number which gave this arithmetic error RESET defaults were reloaded by CTRL X command or switching S2 8 ON NO TEMPERATURE PROBE a temperature reading was requested from a non temperature corrected probe BAD TEMPERATURE READING a temperature reading was requested from a temperature corrected probe but the temperature sensor or associated circuitry is giving an invalid reading FIXED RANGE PROBE an attempt was made to change the range with a single range probe con
34. dow and filtering is temporarily disabled This allows the field reading to follow large rapid field changes while providing good filtering of constant or slowly varying fields The window width can be set using the Y command See page 4 17 The value entered is the half window on either side of the current field reading The default value on system reset is 1 gauss for a total window width of 2 gauss independent of range The digital filter takes the field readings before processing by zero calibrate offset and scale functions and filters the values by performing the following computation F new F old F old J where F old is the previous field reading display F new is the updated field reading display F is the most recent unfiltered field reading J is the filter factor The effective time constant of the filter is dependent upon both the rate at which field measurements are made and the value of J according to the formula T P In J J 1 where Tis the filter time constant P is the period between field measurements Field measurements are made at a fixed rate of 10 per second so P 0 1 A default value of 41 for J is effective when the DTM is reset with the CTRL X command or S2 8 see page 3 6 This gives an effective time constant of 4 seconds The filter time constant may be changed by entering a new value of J using the Jn command See page 4 16 4 20 DTM 151 GPIB User s Manual 4 7 TRIGGERED OP
35. e Clear and Selected Device Clear A device on the bus is cleared by sending a Device Clear Command The device is then initialized to a pre defined device dependant state There are two forms of this command the Device Clear command decimal 20 causes all devices on the bus to be cleared whereas the Selected Device Clear command decimal 4 clears only devices selected to listen Talker Only Mode If a device is set to be a talker only it will output data on the bus using normal handshaking whenever it has data to send This mode is useful in simple systems where a talker only is connected to one or more listener only devices without the need for a controller A talker only cannot receive data and it cannot be programmed through the bus Listener Only Mode A listener only can only receive data It cannot be programmed through the bus nor can it output data For example a printer as a listener only will continuously print all data it receives For full details on the IEEE 488 see the IEEE standard 488 1978 4 5 2 DTM 151 _G IEEE 488 Capability The IEEE 488 Standard defines ten interface functions some with as many as 28 allowable subsets The DTM 151 _G teslameters support the interface functions as listed below See also Appendix C of the IEEE 488 1978 Standard SH1 source handshake capability AH1 acceptor handshake capability T5 talker basic talker serial poll talk only mode unaddressed to talk if addressed to listen
36. e90Jd idi edl Ca Weill au e 9 D DTM 151 GPIB User s Manual 20000569 02000479 6TOGOSTS soooocts 0000 T9 900006 9 10000679 80000609 90000619 S0000 1I9 0000889 10000889 0000689 10000749 9000059 88000049 26000099 16000069 59000059 000 0000189 TOOOOTES 0000189 0000849 70000949 20000089 90000089 00000898 70000089 0000089 96000789 9 80000769 00000 lt 9 80000959 90000969 10000859 9 90000979 1000079 90000579 0001 9 00001v9 10000679 ETOOOTHS 000 9 ZHW 2516 7 vy JO I N6tlLOHPAL NWN NOQOLOHTZ dru2 did 88789 OTT4PSAISA VIA OT dS220G9M SOND HSdOVI69XVW 5 SOHO 314 84540 MS CAG 6 AUOD Dd od SNA 4 8 WOHdd SOHO 114 8 X HCE 992042 H6ICO0 81 94245 230104 4595 20 8 4593 2 did 4 8 Ytosqeu utd 448M GZ 9 MOT JW 339 v 0 5 306 4515 908565 22 0 FG ENE 2048518594 5 0 85 HOT AN 66855 339 70 FG XOT 015 5 AW Geuds 34
37. econds between output field values maximum n 65534 approx 18 hours Scale computes a scale factor to make the field reading equal to the entered value n The one scale factor applies to all ranges The computed scale factor may be in the range 9 9999 to 9 9999 Default field measurement not modified scale factor 1 Display mode hold teslameter display shows peak dc or ac field Display mode normal teslameter display shows current field value Display mode temperature teslameter display shows temperature Offset calls up offset mode and enters offset which is added to all field readings Default 0 n in range 79999 9 to 79999 9 The one offset applies to all ranges Peak hold field requests a peak field reading from the teslameter Test teslameter front panel display Range selection selects 0 3 tesla range Range selection selects 0 6 tesla range Range selection selects 1 2 tesla range Range selection selects 3 0 tesla range Set calibrate enters calibration factor n for the selected range like Cn but enters factor not desired field reading Default n 2 1 Turn OFF EOI line assertion when string terminator is sent Turn ON EOI line assertion Default set by S2 2 Put in a simulated field to replace the measured reading See note p 4 17 DTM 151 GPIB User s Manual SLn SMO SM1 SSO SS1 STn SUO 501 SWAn SWEn SWZn SZn UFG UFT WA WE WZ Yn CTRL D CTRL U CTRL X Set scale e
38. el poll has indicated which device issued the SRQ Performing the serial poll will immediately reset the SRQ line Data must be read from the teslameter by the bus before the device is able to assert the SRQ line again The status byte from the teslameter in response to the serial poll has 2 bits assigned to indicate its status e the least significant bit which appears on bus line DIO1 indicates that the device has data available if asserted and e the next to most significant bit on line DIO7 reflects the status of the SRQ line The status bit in the serial poll response will always be asserted if there is data available to be read The SRQ bit is reset to the false state after the serial poll and is only re enabled when data is read from the teslameter DTM 151 GPIB User s Manual 4 19 4 6 DIGITAL FILTERING The digital teslameter software includes a digital filtering algorithm which may be invoked by an internal switch or by remote command See pages 3 6 and 4 9 Filtering is useful for smoothing out small fluctuations in the field reading In order to speed up the response to large field changes when filtering is on a window can be set to define a band about the current displayed field value Filtering will only occur while the unfiltered field value remains within the window If the field value changes rapidly enough the filtered field reading will not be able to follow fast enough to keep the unfiltered value within the win
39. he waveform is sinusoidal the reading corresponds to its rms value The output impedance is the same as for the dc output 3 8 DTM 151 GPIB User s Manual 3 7 GROUNDING All parts of the teslameter s metal case are connected together to form an integral electric shield around the circuitry inside When the probe connector is plugged into the teslameter and the retaining screws are tightened the probe connector case and the teslameter case are connected together and form an integral shield around the circuitry inside The cable shield is added to the case shield and extends protection from electrical interference almost up to the probe head Because there is an internal connection between teslameter circuit common and the probe connector case when the probe connector is engaged and the retaining screws tightened the teslameter circuit common will be connected to the case Do not make an additional connection between circuit common and the case at any point including at the RS 232C connector or at the G3CL connectors on serial teslameters or at the GPIB connector on teslameters with the IEEE 488 option Such additional connection will form a ground loop and may introduce errors in the measured field value The shielding provided with the above arrangement should be sufficient protection against EMI in most cases especially when the probe cable is shielded Sometimes it may be found helpful to ground the teslameter case to a good electrical gro
40. hout needing the controller to send the F command As a useful diagnostic aid while a system is being set up the effects of the GV V and GET commands on the teslameter can be observed directly by removing its top cover and watching the LED on the analog board During normal continuous operation the LED will be seen to flash about twice per second After the GV command the LED will stop flashing Then each time the GET or V command is given the LED will flash once Continuous operation is restored using the GC command The following sections describe details of triggered operation 4 7 1 Digital filtering with triggered operation If filtering is ON then each time a measurement is triggered the filtering algorithm will calculate a new field value for display and transmission as described in section 4 6 DTM 151 GPIB User s Manual 4 21 The effective time constant will depend on the timing of the V commands If the field values obtained on triggering are required to reflect only the field at the time of triggering and not contain any history then filtering should be turned OFF 4 7 2 Triggered operation timing The teslameter starts sampling the field within 1 5ms after the V trigger command has been received The field is sampled for a period of 8 3ms After sampling the value is digitized and computations are done The new field value is ready no later than 60msec after the V command is received Do not request the new field value
41. id to be selected Any or all devices on the bus which have listener capability may be in the selected state simultaneously When the controller wants to make a device into a talker it places the device s talk DTM 151 GPIB User s Manual 4 9 decimal hex ASCII IEEE 488 value value character mnemonic description PCG Primary Command Group 1 01 SOH GTL Go To Local 4 04 EOT SDC Selected Device Clear 5 05 ENQ PPC Parallel Poll Configure 8 08 BS GET Group Execute Trigger 9 09 HT TCT Take Control 17 11 DC1 LLO Local Lockout 20 14 DC4 DCL Device Clear 21 15 NAK PPU Parallel Poll Unconfigure 24 18 CAN SPE Serial Poll Enable 25 19 EM SPD Serial Poll Disable LAG Listen Address Group 32 62 20 6 Listen addresses 0 through 30 63 UNL Unlisten TAG Talk Address Group 64 94 40 Talk Addresses 0 through 30 95 5F underscore UNT Untalk SCG Secondary Command Group 96 126 60 7E Secondary Commands 0 through 30 96 111 60 6 0 PPE Parallel Poll Enable SCO thru SC15 112 70 p PPD Parallel Poll Disable SC16 127 7F DEL ignored Table 5 IEEE 488 Command Codes address command on the bus This command is given by talk address command decimal 64 device address For example a device whose address is decimal 18 has a talk address of decimal 82 hex 52 ASCII R At any time only one device may be a talker To cause all listeners to stop listening the controller sends the Unlisten command decimal 63 hex
42. igh resolution measurement of magnetic flux densities with direct digital readout in tesla or gauss and IEEE 488 GPIB interfacing for system applications The instruments are light and compact and the probes are easy to use The DTM 151 has been engineered to withstand the severe electrical interference produced by high voltage discharge This description includes features of the serial communications option which is an alternative to the IEEE 488 option If your teslameter is the serial version refer to the DTM 151 _S User s Manual FEATURES Measures magnetic fields over four ranges up to 3 tesla with polarity indication resolution up to 1 part in 600 000 Used with special miniature Hall probe easy to attach to magnet pole or other hardware Probe holders are available as optional accessories Accuracy and temperature specifications include total system performance probe and instrument This is the only meaningful indication of measurement accuracy Probe is calibrated with field and temperature characteristics stored in memory chip contained in cable plug Basic accuracy 0 01 of reading 0 006 of full scale Microprocessor reads probe calibration data stored in probe connector and computes corrected field reading Temperature coefficient 10ppm C overall achieved using temperture sensor in probe Microprocessor calculates corrected field reading Accuracy is verified against nuclear magnetic resonance NMR standard
43. ins details of all our products This site is regularly updated so check it from time to time to learn about recent developments Group3 Technology Ltd 2 Charann Place Avondale Auckland 1026 PO Box 71 111 Rosebank Auckland 1348 New Zealand Phone 64 9 828 3358 Fax 64 9 828 3357 Email info group3technology com Web http www group3technology com Group3 Technology Ltd 2 Charann Place Avondale Auckland 1026 P O Box 71 111 Rosebank Auckland 1348 New Zealand Phone 64 9 828 3358 Fax 64 9 828 3357 email info group3technology com web www group3technology com CONTENTS 1 General Description 1 1 2 Specifications of 151 System 2 1 3 Setting Up 3 1 Introduction 3 2 Connecting the Hall Probe 3 3 Connecting the Power Source 3 4 GPIB Connection 3 5 Internal DIP Switch Settings 3 6 Analog Outputs 3 7 Grounding 3 8 Installing the Panel Mount Option 3 9 Installation Techniques for Electrically Noisy Environments C CO PM 1 4 Operating Instructions 4 1 Zeroing 4 1 4 2 Installing the Probe 4 2 4 3 Reading the Field Value 4 3 4 4 Display Modes Using the Front Panel Keys 4 4 4 5 Using the IEEE 488 GPIB Interface 4 7 4 6 Digital Filtering 4 20 4 7 Triggered Operation 4 21 5 Technical Diagrams General Information 5 1 Display Board Schematic 5 2 Display Board Component Overlay 5 3 Display Board Parts List 5 3 Probe Plug Board Schema
44. lace it in the desired position 3 6 ANALOG OUTPUTS 3 6 1 Connectors Two output signals are available at the rear of the teslameter These signals are referred to as the dc and ac outputs and are described below The analog outputs are not corrected for linearity or temperature errors The cable connector required is a Molex receptacle type M5051 4 fitted with M2759 terminals It carries both outputs Pin assignments are given below pin signal 1 ground 2 ac output 3 ground 4 dc output Table 4 Analog Output Connector Pin Assignments 3 6 2 DC Output The dc output is the Hall probe signal amplified to 3 volts full scale and gives an indication of the instantaneous field value from dc to 3kHz 3dB with a roll off of 60dB decade Field direction is indicated by the output voltage polarity There is a small zero offset arising from the probe zero field output and amplifier offsets The output impedance is 1000 ohm with a 10nF capacitor to common for noise filtering 3 6 3 AC Output The ac output is a positive voltage analog of the time varying or ac field component To generate this output the instrument removes the dc component of the analog output described above then full wave rectifies any remaining ac component The overall response to varying fields is 8Hz to 3kHz and the rectified output has a time constant of 0 2 seconds The rectifier circuit responds to the average value of the ac waveform but is calibrated such that if t
45. lk LEO no address extension listener capability SR1 service request capability RLO no remote local capability PP1 parallel poll capability configured by controller DC1 device clear capability DT1 device trigger capability CO controller capability standard Amphenol 57 20240 with metric standoffs DTM 151 GPIB User s Manual 2 3 Memory back up Power source Enclosure Ambient field Temperature range Instrument weight Probes user entered data storage for 30 days with power off ac min 8V at 0 7Arms max 15V at 0 4Arms dc min 9V at 0 5A max 19V at 0 25A ac line input plugpack supplied Power fuse on processor board 1 amp antisurge 5 x 20mm To obtain maximum spark protection use PS12D7 power supply and ferrite kit 11000036 See section 3 9 L option 115 208 230 V ac power input aluminum 217 x 125 x 50 mm textured finish light tan color tilt stand fitted to bench models Maximum operating field for instrument 10 millitesla with single range probe 0 5 millitesla with multi range probe 0 to 50 C operating absolute maximum temperature of probe 60 C 1 2 kg shipping weight 2 5 kg LPT series transverse types sensitive area 4 x 1 6mm probe head size LPT 141 and LPT 231 14 x 14 x 2 5 mm MPT series miniature transverse types sensitive area 1 0 x 0 5mm probe head size MPT 132 MPT 230 MPT 141 MPT 231 14x 5x 2 mm Standard cable length 2 meters Special cable lengths
46. mended that the instrument be re zeroed if the ambient temperature has changed significantly 4 2 INSTALLING THE PROBE Group3 Hall probes are built to be as robust as possible for a small precision device However it is most important that certain precautions be taken when handling and installing probes so that they are not damaged or destroyed and to preserve their accurate calibration Mount the probe head so there is no pressure which will tend to bend or depress its ceramic rear surface If the probe head is clamped make sure the surface in contact with the ceramic is flat and covers the whole of the ceramic surface Do not apply more force than is required to hold the probe in place Any strain on the ceramic will alter the probe s calibration and excessive force will destroy the Hall element inside When the probe head is mounted the cable should be clamped firmly nearby so it cannot be torn away from the probe head if accidentally pulled The flexible section adjacent to the probe head can be carefully folded to allow the cable to come away in any direction but avoid repeated flexing of this section Keep the cable out of the way of foot traffic Do not pinch the cable or drop sharp or heavy objects on it A severed cable cannot be re joined without altering the probe s performance and requires factory repair and re calibration The probe can be fitted to a Group3 probe holder part no 17000050 for the LPT 141 and LPT 231 part
47. mensions in mm target error 0 3mm angular error in transverse plane 1 max seating error on ceramic 0 4 max MPT 141 and MPT 231 reference surface 3 2 dia nom 1 0 max 14 0 0 2 ceramic 5 0 dia nom 2 4 0 01 9 5 0 o main cable 20 nom d 50 2 exposed ceramic area 1 5 10 2 4 5 dia nom cable junction flexible wires 0 3 wide min 2 0 2 M 2 0 9 0 1 sensitive area is on centerline of epoxy 0 2 0 62 40 02 all dimensions in mm angular error in transverse plane X1 max seating error on ceramic 0 4 max Fig 5 Probe Dimensions 4 3 READING THE FIELD VALUE The field value is read directly off the display A negative sign indicates that the field direction is opposite to that described in section 4 2 For maximum resolution select the lowest range which will display the field value See sections 4 1 and 4 4 for range selection instructions If the field reading is greater than full scale the message o rAnGE will be displayed Change to a higher range until the message clears The field DTM 151 GPIB User s Manual 4 3 be displayed in tesla or gauss with the appropriate indicator showing the units in use To change the units see section 3 5 page 3 6 4 4 DISPLAY MODES USING THE FRONT PANEL KEYS 4 4 1 The Keys Two front panel keys are used to control the
48. n designated bus data line More than one device can respond on each data line The data line assigned to a device and the logic sense of the response is configured by a PPOLL CONFIGURE sequence as follows 1 the device is addressed to listen 2 the Parallel Poll Configure command PPC hex 05 is sent 3 the Parallel Poll Enable code is sent This code belongs to the Secondary Command Group decimal 96 to 111 In this code bits 6 and 7 are always set Bits 1 2 and 3 carry a binary code to specify which of the 8 data lines the device will use to send its status and bit 4 is used to determine the logic sense of the status For example if bits 1 through 4 were all 0 the device would place 0 on data line 1 during a parallel poll if its status response were in the affirmative 4 the Unlisten command is sent Now if the controller executes a parallel poll by asserting the ATN and EOI lines simultaneously the configured device s respond as described above and the controller reads the data lines The parallel poll response can be disabled in two ways e Parallel Poll Unconfigure PPU command from the controller will cause all devices on the bus to ignore subsequent parallel polling The devices are not addressed to listen before this command e the PPC command followed by Parallel Poll Disable PPD will disable parallel polling only in devices which have been selected addressed to listen 4 12 DTM 151 GPIB User s Manual Devic
49. nected to the teslameter NO PROBE a field reading was requested when a probe was not connected OVERFLOW the computed field value was outside the range 199999 9 OVER RANGE the current field being measured is too high for the selected range 4 5 5 GPIB Handshaking Once a handshake sequence has begun on the bus it should always be allowed to finish in a normal fashion If it is stopped part way through by an asynchronous bus take over then an IFC uniline command should be issued before another handshake sequence is initiated If the second handshake starts with ATN false before the IFC while the teslameter is in the listener state the device will not read from the bus correctly and will have to be reset When the controller performs a serial poll on the teslameter it must ensure completion of the handshake for the status byte If it does not do this the device s ability to function as a talker is adversely affected until such time as the controller places the teslameter into the SPAS serial poll active state and completes the handshake for the serial poll status byte 4 18 DTM 151 GPIB User s Manual 4 5 6 Serial Poll A serial poll is performed on a device in this case a teslameter for two reasons e to check on its status by decoding the byte output in response to the serial poll and e to reset SRQ line In systems employing interrupts SRQ function is enabled the serial poll will usually be performed after a parall
50. ng probes so that they are not damaged or destroyed and to preserve their accurate calibration Mount the probe head so there is no pressure which will tend to bend or depress its ceramic rear surface If the probe head is clamped make sure the surface in contact with the ceramic is flat and covers the whole of the ceramic surface Do not apply more force than is required to hold the probe in place Any strain on the ceramic will alter the probe s calibration and excessive force will destroy the Hall element inside When the probe head is mounted the cable should be clamped firmly nearby so it cannot be torn away from the probe head if accidentally pulled The flexible section adjacent to the probe head can be carefully folded to allow the cable to come away in any direction but avoid repeated flexing of this section Keep the cable out of the way of foot traffic Do not pinch the cable or drop sharp or heavy objects on it A severed cable cannot be re joined without altering the probe s performance and requires factory repair and re calibration Your DTM must be used with a Group3 Hall probe The probe may be one supplied with your teslameter or it may have been obtained separately In any case calibration is preserved when probes are exchanged between instruments In order to obtain DTM 151 GPIB User s Manual 3 1 specified performance the DTM 151 should be used only with 141 and 231 series probes The standard probe cable le
51. ngth is 2 meters Probes with non standard cable lengths up to 30 meters may be ordered from your Group3 supplier The cable used for Group3 probes is shielded to reduce pickup of induced noise from external sources Such noise may reduce the accuracy of the instrument cause malfunctioning or in extreme circumstances even result in damage to the internal circuitry See section 3 9 of this manual With the DTM unpowered plug the probe connector into the instrument The pin side of the plug is inserted into the large opening in the rear of the DTM with the plug s label uppermost when the instrument is standing right way up It is easy to find the correct mating position for the plug and then push it fully home but if any difficulty is experienced at first remove the DTM s top cover by loosening the central screw and lifting the cover off Now it is possible to see when the plug is centrally located and its overhang slides over the card edge receptacle ensuring that its pins engage correctly Tighten the connector retaining screws finger tight Do not leave these screws loose as they form part of the shielding system around the teslameter The teslameter should always be used with both covers attached Always disconnect power from the teslameter before connecting or disconnecting the probe If the probe connector is inserted or withdrawn with power on data stored in memory may be corrupted leading to erroneous field readings If this happens the
52. nication distance The IEEE 488 option fully supports all relevant GPIB functions and commands including full talker listener capability serial and parallel polling service request and talker only ASCII control commands are accepted to modify the output data format to change the rate of data transmission or to request transmission of a single field reading Other commands set scaling and offset select the field range select ac and peak hold functions turn on and off digital filtering and modify the filter characteristics System status may be determined remotely The system can be operated in triggered mode where field measurements by one or more teslameters are triggered in synchronism with each other by external command Internal switches select serial data format and baud rate device address string terminators filtering field units in gauss or tesla data format service request action EOI action and perform system reset Two analog outputs are available instantaneous field value 0 to 3 kHz rectified time varying ac component of field 8 Hz to 3 kHz All model variations are available without display and keys for true black box magnetic field to computer interfacing A panel mount model with display is available 1 2 DTM 151 GPIB User s Manual 2 SPECIFICATIONS DTM 151 SYSTEM Measurements Field ranges Resolution Resolution Accuracy Temperature Stability Time stability Specificatio
53. no 17000081 for the MPT 141 and MPT 231 Probe holders that orient the probe head to the axial position are also available from Group3 suppliers The holders protect probes and provide additional cable strain relief Alternatively the probe can be clamped using the machined detail in each side of the metal cap The probe will measure the component of the field which is normal to the flat surface of the probe head The point of maximum sensitivity is marked by a target printed on the top of the probe head A positive indication will be obtained when the magnetic field vector enters this side of the probe The target represents the tail of the vector arrow 4 2 DTM 151 GPIB User s Manual Magnetic field convention is that field lines are directed from N pole to an S pole Fig 8 gives the dimensions of the two styles of probe and shows the position of the most sensitive point If the exact direction of the magnetic field is unknown its magnitude can be measured by putting the DTM in the peak hold mode and slowly rotating the probe As the probe turns and the measured field rises and falls its maximum value is held on the display See section 4 4 2 page 4 4 LPT 141 and LPT 231 ceramic reference surface sensitive aluminium cap area 21 4 5 dia nom 5 0 dia nom 1 6 x 4 0 Pp I 12 0 0 1 14 0 1 0 30 1 23 Dares E 20 nom 13 nom 14 0 0 2 1 30 2 main cable rigid cable junction flexible wires all di
54. not a high current path so if there is any possibility of an arcing discharge hitting the probe area then the probe head and part or all of the cable must be enclosed in a metal tube non magnetic near the probe head or shielded in some other way 3 10 DTM 151 GPIB User s Manual The probe cable should be routed away from any power high current or high voltage wiring It should be shielded from any capacitively coupled noise effects If the cable runs close to any section of the apparatus that could be subjected to a very rapid change of potential when a spark discharge occurs then the probe cable may need additional shielding to prevent capacitive coupling of the noise The retaining jack screws designed to hold the probe connector onto the teslameter must be screwed up finger tight as they form part of the electrical connection of the shield system The woven braid of the probe cable is terminated to the probe connector case The retaining screws then connect the probe connector case to the teslameter case The teslameter itself should be sited in a sheltered location where it will not be exposed to spark discharges or radiated or capacitively coupled noise The teslameter case is made of metal for shielding reasons However of necessity it is less than perfect as apertures have to be left in the case for the display and various connectors etc The unit is a precision measuring device and should be treated with care not subjected to
55. ns include LPT 141 or MPT 141 Hall Probe field value and time varying ac component of field 0 3 0 6 1 2 3 0 tesla full scale 3 6 12 30 kilogauss full scale with polarity indication maximum calibration field 2 2 tesla 22 kilogauss DC mode with digital filtering ON 1 in 600 000 of bipolar span as shown on front panel display range display resolution serial GPIB resolution gauss tesla gauss tesla 0 3 tesla 0 01 0 000001 0 001 0 0000001 0 6 tesla 0 02 0 000002 0 01 0 000001 1 2 tesla 0 04 0 000004 0 01 0 000001 3 0 tesla 0 1 0 00001 0 01 0 000001 DC mode with digital filtering OFF and AC mode 1 in 120 000 of bipolar full scale span in display range display resolution serial GPIB resolution gauss tesla gauss tesla 0 3 tesla 0 05 0 000005 0 001 0 0000001 0 6 tesla 0 1 0 00001 0 01 0 000001 1 2 tesla 0 2 0 00002 0 01 0 000001 3 0 tesla 0 5 0 00005 0 01 0 000001 20 bit digitizing of field reading DTM 151 with LPT 141 or MPT 141 probe 0 01 of reading 0 006 of full scale max at 25 C DTM 151 with LPT 141 or MPT 141 probe calibration 10 ppm of reading C max zero drift 1 microtesla 0 0003 of full scale C max add 3ppm C for each meter of probe cable 0 1 max over 1 year DTM 151 GPIB User s Manual 2 1 Measurement rate Response time Peak hold mode AC mode Display Indicators Display modes Digital filtering Keys Digital interfacing Digital data format
56. nted by n in the table If no number is entered where one is expected zero will be entered automatically If an error message is returned the command must be re entered The default values apply after command CTRL X For switch selectable defaults see Table 2 page 3 6 TABLE 7 DTM 151 _G IEEE 488 COMMANDS command description B lt text gt lt cr gt Displays ASCII text on teslameter display 7 characters maximum lt gt Cancel text mode return to normal display Cn Calibrate calls up the calibrate function and defines the current field measurement as equal to the entered value n Command applies to the range selected only Separate calibration factors are stored for each range Default field measurement not modified calibration factor 1 DO Turns OFF digital filtering D1 Turns ON digital filtering Default set by S2 7 EC Erase calibration sets calibration factor to 1 on current range EL Erase scale factor sets scale factor to 1 all ranges EO Erase offset sets offset to 0 all ranges EP Erase reset peak hold field value EZ Erase zero cancels zero correction on current range F Field reading requests a field reading from the teslameter GA General function AC puts teslameter in ac field measurement mode GD General function DC puts teslameter in dc field measurement mode GC General function Continuous teslameter measures continuously GV General function Triggered teslameter measures when triggered
57. nters scale factor n for all ranges like Ln but enters factor not desired field reading Default n 1 Send mode field readings sent when requested by F command only Send mode field readings sent at intervals defined by Kn command Turns off SRQ line assertion when data is available Turns on SRQ line assertion Default set by S2 1 Put in a simulated temperature to replace the real reading See note below Turns OFF units symbol sent after field and temperature readings Turns ON units symbol sent after field and temperature readings Default set by S2 6 Put in a simulated raw field at the ADC output See note below Put in a simulated raw field after EEPROM calibration See note below Put in a simulated raw field after zeroing See note below Set zero enters a zero offset n for the selected range Temperature requests a temperature reading from the teslameter Units field values displayed and sent in gauss Units field values displayed and sent in tesla Default set by S2 5 Triggers field measurement after triggered operation selected by GV Raw field returns uncalibrated field reading direct from ADC Returns raw field reading after teslameter internal calibration Like WE but field reading has user entered zero offset applied Cancels simulated field and temperature Window enters n window within which digital filtering occurs Default 1 gauss Maximum n 65534 Zeroing calls up zeroing mode and defines current field rea
58. oDppDnooonpnm cond ci e A AA mmu k OE OD oc O0 6 n e iD uo o Ba Hi mb fuif hh f f fn m m pm m GP OF 01 D ed OC QD ANd TAN AND dA Md ted 34 14 44 24 MANN A 4 9 04 4 4 4 04 eH 64 45430 Neu 5 DONd 88v Hd4I ISI O0GI WIG SLONWOdd LNXWOUOSVINW GCISII OIIINOVAR LSTT GSXLINII ADO IONHOGL dnowdd DTM 151 GPIB User s Manual 5 8 1 71 SILUH3HOS Q3U08 9071UNU ISI H1G M N 2 GNU DIOnV wesasos 11 2 os Q11 A9010NHO31 4059 3NOOT 283 ib T83 450762 SZN 450182 vzn 3ner FS Teo 5 2 1 252 100412 919045 ZHMO t Ue TA 46802209 3361 zn NON 8Z 3190 92001051 2ILUH3HOS 13908 9019 9 TST HLA 2 2 MNW83S03 Od 011 A9010NHO31 ED EZX 5 dOTIHFL OTOHEZ FIT 35 ZH 6 sin 02858424 20 PONT moi ae GESTAPO szn 5 9 DTM 151 GPIB User s Manual 13385 _ ee now sz 3140 001021 QILYW3HIS 9
59. oint nearby If the teslameter is sitting on metalwork then it should really be grounded to that metalwork so it is at the same potential DTM 151 GPIB User s Manual 3 11 Further Preventative Measures If problems are still encountered despite following the precautions detailed above then there are some further things to try Tests have shown that in an electrically noisy environment the main path of noise entry to the teslameter is through the low voltage power supply input The trouble could come from mains borne transients working their way through the plugpack transformer or from interference picked up on the low voltage lead itself The quickest and simplest fix for this problem is to wind the power lead several times through a ferrite core Use a thick walled ferrite tube of substantial size a simple small torroid is not nearly as effective A suggested ferrite is the TDK part number HF70RH26x29x13 This is a tubular ferrite 29 mm long 26mm outside diameter and 13mm inside diameter Winding the power lead four times through this core really close to the teslameter significantly reduces noise upsets If the analog outputs are wired up then shielded twisted pair should be used for all wiring routed away from any high current or high voltage cabling In a really noisy environment it can be beneficial to put this analog cabling through a ferrite tube for a few turns to suppress induced noise The probe cable itself can be pas
60. ption Go To Local Selected Device Clear Parallel Poll Configure Group Execute Trigger Local Lockout Device Clear Parallel Poll Unconfigure Serial Poll Enable Serial Poll Disable Listen addresses 0 through 30 Unlisten Talk Addresses 0 through 30 Untalk Parallel Poll Enable SCO thru SC15 Parallel Poll Disable SC16 Table 6 DTM 151 G IEEE 488 Command Codes The Device Clear and Selected Device Clear commands perform device specific functions In the teslameter these commands cause the following to occur 4 14 normal field display selected highest range selected if 4 range probe is in use peak hold value reset triggered mode cancelled IEEE 488 I O buffers cleared IEEE 488 software reinitialized serial poll byte and SRQ cleared parallel poll unconfigured DTM 151 GPIB User s Manual 4 5 3 DTM commands In addition to the IEEE 488 commands listed in the previous section the teslameter responds to a set of DIM commands which are listed in Table 7 below These commands are in the form of ASCII coded data which are sent to the teslameter by the system controller on the bus Note that DTM commands are data as far as the bus is concerned and are not to be confused with IEEE 488 commands The distinguishing feature is that with IEEE 488 commands the controller asserts the ATN line The commands are in the form of one to three ASCII alphabetical characters and in some cases are followed by a decimal number represe
61. quests Often IEEE 488 compatible devices have the ability to generate a service request when they require some action on the part of the active controller A service request is usually issued when the device has completed a task or if an error condition has occurred To request service the device asserts the SRQ line This usually causes an interrupt in the active controller so it enters an interrupt service routine which services the event In general the service routine will take the following actions determine which device is requesting service parallel poll ascertain the action required serial poll re enable interrupts 1 2 3 execute the required action 4 5 return to the task in hand before being interrupted The SRQ line is released by the device when the serial poll is performed DTM 151 GPIB User s Manual 4 11 Serial Polling When a Serial poll is done on a device it causes the device to output a byte which indicates its status or condition Each bit indicates the status of some device dependant parameter Usually data line 7 reflects the status of the SRQ line Parallel Polling The fastest way for the active controller to ascertain the status of several devices on the bus is to perform a parallel poll The devices to be polled must have parallel poll capability and must have been previously configured by the controller During a parallel poll each configured device responds by placing its status on its ow
62. rchantability and fitness for a particular purpose The Company is not liable for consequential damages 83000001 Group3 Technology Ltd DISTRIBUTORS amp REPRESENTATIVES European Region United Kingdom Pulse Power amp Measurement Ltd 65 Shrivenham Hundred Business Park Watchfield Swindon Wiltshire SN6 8TY UK Tel 44 0 1793 784389 Fax 44 0 1793 784391 email sales ppm co uk website www ppmpower co uk Denmark Sweden Norway Finland Iceland Belgium Holland Italy Turkey Russia India Danfysik A S Mollehaven 31 P O Box 29 DK 4040 Jyllinge Denmark Tel 45 4679 0000 Fax 45 46790001 Contact Erik Steinmann email es danfysik dk website www danfysik com Germany Poland Czech amp Slovak Republics Ukraine Schaefer Technologie GmbH M rfelder Landstrasse 33 D 63225 Langen Germany Tel 49 6103 30098 0 Fax 49 6103 30098 29 Contact Martin Schaefer email info schaefer tec com website www schaefer tec com Switzerland Austria Schaefer Tec AG Badimatte 21 Postfach 431 CH 3422 Kirchberg Switzerland Tel 41 34 423 70 70 Fax 41 34 423 70 75 Contact Martin Bossard email ch schaefer tec com website www schaefer tec com France Spain Portugal Schaefer Techniques Sarl 1 Rue du Ruisseau Blanc F 91620 Nozay France Tel 33 1 6449 6350 Fax 33 1 6901 1205 Contact Christophe Dubegny email info schaefer tech com website www schaefer tech com Italy Schaefer Italia SRL Via Minzoni 57 1 45100 Rovigo I
63. s a pre terminator character before the final string terminator selected by S2 3 The pre terminator is the character not selected by S2 3 The terminator sequence as selected by S2 3 and S2 4 is as follows S2 3 OFF ON OFF If cr 52 4 cr If If cr Table 3 String Terminator Switch Settings Check which terminator characters are required by the system controller and or other devices in your GPIB system and set the switches accordingly 52 5 selects the field units used OFF for tesla ON for gauss 52 6 when ON causes the field units character T or to be sent on the bus following numerical field values S2 7 enables digital filtering of the field value when switched ON 52 8 allows the user to reload default settings where all the numerical values entered by the operator are returned to their default values and switch selectable functions are instated as set on the switches To load defaults switch 52 8 ON wait 1 second then DTM 151 GPIB User s Manual 3 7 switch OFF again If the switch is left ON defaults will be loaded each time the teslameter is powered up The display shows the message rESEt each time defaults are loaded When defaults are loaded on power up the rESEt message follows the Group3 power up message The functions of S2 1 2 5 6 7 8 can be selected remotely on the bus by DTM commands See page 4 15 To revert to switch control change the switch setting and then p
64. s immediately prior to making critical field measurements The zeroing process takes out residual zero errors in the Hall probe and the instrument s preamplifier front end The instrument must be zeroed if it has not been powered for 30 days or more as there is a possibility that its memory back up may have failed Zeroing is mandatory if a different probe is to be used since the instrument was last zeroed You should also zero the instrument when using it for the first time The ac ranges must also be zeroed individually Before zeroing the system connect up and apply power as described in sections 3 2 and 3 3 Allow 30 minutes for the instrument and probe to stabilize For absolute zeroing place the probe in a zero field region either in a zero field chamber or inside a suitable magnetic shield so that the probe is shielded from the earth s magnetic field and other stray fields If desired a relative zero setting may be done the instrument is zeroed after the probe is placed in its measurement position Thus any ambient field is automatically subtracted from subsequent measurements The probe should not be moved once zeroing is complete About 5 of full scale may be zeroed out without reducing full scale span below specification The zero field reading is affected slightly by the presence of metal against the probe s back surface If the probe is to be used clamped to a metal surface or in a probe holder it should be zeroed in the s
65. s on the studs then the lock washers and finally DTM 151 GPIB User s Manual 3 9 screw on the nuts Make sure the teslameter is resting on the bracket then tighten the nuts preferably using a long stemmed nut driver Bezel Outline 45 52 56 127 EN 4 holes 137 032 145 all dimensions in mm Fig 4 Panel Cutout Dimensions 3 9 INSTALLATION TECHNIQUES FOR ELECTRICALLY NOISY ENVIRONMENTS The DTM 151 is a precision electronic measuring device Because of the nature of the measurements it is asked to do it is frequently exposed to conditions that are considerably worse than are normally encountered by precision instruments Therefore the teslameter has been carefully engineered to be as immune as possible to sparks and other forms of interference through the use of several kinds of power input filtering and a special high isolation switchmode power module built into its circuitry The design has been verified by extensive testing using high energy sparking in close proximity to both the teslameter instrument case and the probe Nevertheless due care should always be taken when installing the teslameter system The teslameter and its probe must be protected from any chance of receiving a direct hit by a high voltage discharge The probe should have shielded cable if the meter is to be used in an electrically noisy environment The cable shield is an RFI screen
66. sed through a ferrite core The internal diameter will need to be sufficient to pass the probe head through An MPT miniature probe head is nearly the same size as shielded cable 6 5mm diameter but an LPT probe head needs an internal ferrite diameter of 14mm or more Alternatively a split core ferrite variety can be used such as TDK part HF70RU16x28x9 The core should be placed where the probe cable enters the probe connector and optionally a second ferrite can be placed where the cable shield layer ends approximately 300mm back from the probe head Group3 can supply an alternative power supply to be used instead of the usual plugpack The alternative power supply is model PS12D7 It is a universal voltage 85 270V 50 60Hz input 12Vdc 7W output unit with excellent input output isolation for noise and transients The PS12D7 is DIN rail mounted In conjunction with the PS12D7 we recommend the use of our ferrite kit part no 11000036 which implements the ferrite filtering measures described above The kit consists of a 1 2 meter length of twin cord with a ferrite tube fitted This cord is intended to connect between the PS12D7 and the teslameter The kit also contains a split ferrite tube and housing for fitting to the probe cable 3 12 DTM 151 GPIB User s Manual 4 OPERATING INSTRUCTIONS 4 1 ZEROING The DTM 151 digital teslameter has a very stable zero field reading Nevertheless it is good practice to zero the instrument on all range
67. shows peak hold mode is operating If filtering is on the filtered field value is held Reset is performed by pressing both keys together The peak value is also reset if the field polarity changes d Peak ac measurement Combination of b and c above 4 4 DTM 151 GPIB User s Manual e Probe temperature display in degrees Celsius 4 4 3 Display Messages Power up message The message GrouP 3 appears in the display for 2 seconds when the teslameter is first powered or when a GPIB command restarts the operating software see section 4 5 No Probe The message noProbE is displayed if the Hall probe is disconnected from the instrument While the message is visible all key functions are disabled No Temperature Sensor The message noPrb is displayed for 2 seconds after the Group3 power up message if the probe is not a temperature corrected type e g LPT 130 LPT 230 MPT 132 MPT 230 The message is also displayed if the MODE key is pressed to display what would have been the probe temperature reading This message warns the user that the field reading is not temperature corrected and therefore the accuracy will be less than would be obtained with a temperature corrected probe LPT MPT 141 231 Temperature Error The message is displayed in place of the temperature reading if a temperature corrected probe is in use but there is a fault with the probe s temperature sensor or associated wiring or circuitry Again
68. t the time 2 acommand can be sent by asserting the ATN line and placing the command on the data lines the command is read by every device on the bus with normal handshaking as described above An example of this is the Device Clear command which resets all devices on the bus to their specific predefined device dependant states 3 a command can be sent to specific devices First the controller sends the listen address command of the devices which are to receive the command Then the command itself is sent to be received only by the devices addressed to listen Command messages are sent on the data bus using 7 bit ASCII code and are distinguished from data messages by the state of the ATN line ATN is asserted for commands Command messages fall into four groups as shown in Table 5 below The groups are the Primary Command Group the Listen Address Group the Talk Address Group and the Secondary Command Group Address Commands When the controller wants to make a device behave as a listener it places the appropriate listen address command on the bus The command is given by listen address command decimal 32 device address For example if the device address is decimal 18 hex 12 then the decimal number 50 hex 32 ASCII 2 is placed on the data lines as a binary coded 7 bit number while the ATN line is held asserted This causes the device whose address is decimal 18 to become a listener In IEEE 488 parlance the device is sa
69. taly Tel 39 0425 460 218 Fax 39 0425 462 064 Contact Paulo Bariani email italia schaefer tec com website www schaefer tec com China MT Electronic Co Ltd Room 503 No 24 Building Jing Tong Yuan Sunny Uptown International Department Chao Yang District Beijing China 100024 Tel Fax 86 10 6570 0095 mobile 86 130 0116 1549 Contact Liang Qing Rosalind email Iqrosalind yahoo com cn website www mt elec com India Transact India Corporation 5 1A Grants Building Arthur Bunder Road Colaba Mumbai 400 005 India Tel 91 22 2285 5261 or 2283 4962 extn 22 or 2202 8735 Fax 91 22 2285 2326 email sales transact co in Contact Arish Patel arish transact co in direct dial 91 22 563 64866 Israel Scientific Products amp Technology 3000 Ltd P O Box 1425 Rosh Ha Ayin 40850 Israel Tel 972 3901 4479 Fax 4972 3 901 4481 Contact Rafael Thaler email info_spt netvision net il website www spt co il Japan Hakuto Company Ltd Scientific Equipment Department 1 13 Shinjuku 1 chome Shinjuku ku Tokyo 160 8910 Japan PO Box 25 Tokyo Central 100 8691 Tel 81 3 3225 8051 81 3 3225 9011 website www hakuto co jp Contact Mr Tsugio Saitoh email saito tsugio hakuto co jp Contact Mr Shunsuke Takahashi email takahashi shunsuke hakuto co jp United States Canada GMW Associates magnets magnetic instrumentation control systems 955 Industrial Road San Carlos CA 94070 P O Box 2578 Redwood City CA 94064 U S A Tel
70. ten At any time there can be only one active talker but as many active listeners as desired The speed of data transmission between talker and listener will be limited by the speed of the slowest listener Each device on the bus is assigned a unique address in the range to 30 The address is usually set by switches on the device The switches may be located on the back panel or internally When the controller wishes to designate the talker and listeners for the next sequence of bus transmissions it asserts the bus management line called Attention ATN and then sends the appropriate talker and listener address commands to assign the desired talker and listener s required for the next transaction The controller then releases the ATN line thus allowing the talker to start sending its data on the bus The ATN line distinguishes commands from data When a controller is about to set up such a 4 8 DTM 151 GPIB User s Manual transaction it is normal practice first to send a single command which causes all devices to unlisten Devices which have not been addressed to listen simply ignore the data being sent and so have no effect on the transmission When configuring a system the controller can send commands to the other devices in one of three ways 1 a command can be sent by asserting one of the 5 bus management lines for example asserting the Interface Clear IFC line resets the bus to an idle state irrespective of bus activity a
71. tener devices The IEEE 488 interconnection cable contains 16 signal lines in three groups 8 data lines 3 handshake lines 5 bus management lines All these lines connect to all the instruments on the bus The logic sense on the actual bus wires is low true The 8 data lines allow bit parallel byte serial data transmission between units on the bus The data lines are used to send data from talkers to listeners and to send data and commands from controllers to talkers and listeners The three handshake lines are Valid DAV Not Ready For Data NRFD Not Data Accepted NDAC NRFD is high false to indicate that all devices on the bus are ready for the next data transmission If any device is not ready it pulls NRFD low asserted which inhibits data transmission When a talker is ready to send data it places the data on the 8 data lines and asserts the DAV line As each listener on the bus accepts and reads the data it removes its assertion of the NDAC line Thus the NDAC line stays asserted until the slowest unit on the bus has accepted the data and releases the line Now the talker can take the data off the bus which becomes available for the next transaction There can be only one System Controller on the bus However the System Controller can pass control to another controller which is then called the active controller It is the responsibility of the active controller to determine which device can next talk and which can lis
72. teslameter Changes of state occur as a key is released not as it is depressed The MODE key used on its own rolls the instrument through the various operating modes in sequence dc field ac field peak hold field peak hold ac field and probe temperature as described in 4 4 2 below The RANGE key selects the range without changing the display mode The keys are pressed together at the same time to zero the display The same action is used to reset the display in the peak hold mode 4 4 2 Operating Modes a Field dc display Four ranges 0 3 0 6 1 2 and 3 0 tesla full scale are selected in sequence by pressing the RANGE key Four range indicators show the range in use If a high sensitivity probe is connected to the teslameter the actual full scale ranges are one tenth of those shown above i e 0 03 0 06 0 12 and 0 3 tesla The magnetic field measurement is displayed with up to seven digits A minus sign is added to indicate reverse polarity fields Press the keys together to zero the display The display shows ZEro Field reading is filtered if selected by the internal switch see p 3 9 b AC field measurement ranges and zeroing as above Shows the value of time varying component of field This mode is indicated by A appearing in the left hand display character c Peak hold display ranges as above Displays maximum field measurement taken either polarity since entering the mode or since last reset HOLD indicator
73. tic 5 4 Probe Plug Board Component Overlay 5 5 Probe Plug Board Parts List 5 5 Processor Board Schematic 5 6 Processor Board Component Overlay 5 7 Processor Board Parts List 5 8 Analog Board Schematic 5 9 10 Analog Board Component Overlay 5 11 Analog Board Parts List 5 12 13 DTM 151 GPIB User s Manual Contents 1 LIST OF FIGURES Fig 1 Power Input Connections of the L option Fig 2 IEEE 488 Standard Connector Fig 3 Location of Processor Board Switches Po A Panel Cutout Dimensions Fig 5 Probe Dimensions Fig 6 A Typical IEEE 488 System Display Board Schematic Display Board Component Overlay Display Board Parts List Probe Plug Board Schematic Probe Plug Board Component Overlay Probe Plug Board Parts List Processor Board Schematic Processor Board Component Overlay Processor Board Parts List Analog Board Schematic Analog Board Component Overlay Analog Board Parts List LIST OF TABLES Table 1 GPIB Connector Pin Assignments Table 2 Switch Functions Table3 String Terminator Switch Settings Table 4 Analog Output Connector Pin Assignments Table5 IEEE 488 Command Codes Table6 DTM 151 IEEE 488 Command Codes Table7 DTM 151 IEEE 488 Commands Contents 2 3 5 3 5 3 10 4 7 5 2 5 3 5 4 5 5 5 5 5 7 5 8 5 9 10 5 11 5 12 13 3 4 3 6 3 7 3 8 4 10 4 14 4 15 16 17 DTM 151 GPIB User s Manual 1 GENERAL DESCRIPTION The DTM 151 _G Digital Teslameters offer accurate h
74. to 30 meters Probe cable is shielded DTM 151 GPIB User s Manual ORDER CODES Basic teslameters capable of four measurement ranges 0 3 0 6 1 2 3 0 tesla full scale support all LPT and MPT series probes plugpack supplied except for option L DTM 151 supports LPT 141 LPT 231 MPT 141 MPT 231 probes Options Bench style instrument with display add suffix D Panel mount version add suffix P one of these options Without display plugpack powered add suffix N must be specified Without display line voltage power add suffix L IEEE 488 GPIB capability add suffix G must select Serial data input output RS 232C amp fiber optic add suffix one option Example DTM 151 DG Probes Four ranges standard 2 meter shielded cable LPT 141 2s standard sensitivity LPT 231 2s high sensitivity MPT 141 2s probes MPT 231 2s probes Single range probes add range suffix 03 06 12 30 Special probe cable lengths change length suffix to Xs where X is the desired cable length in meters 30 max Example LPT 141 10s for 10 meter cable Accessories fiber optic cable fitted with connectors 60 meter length maximum probe holders fiber optic repeater bidirectional model FOR 2PP fiber optic to RS 232C adaptor model FTR serial GPIB adaptor model COM 488 digital display for remote control amp readout of field values model DPM rack panels 3 5 inches high 2U for rack mounting 1 2 or 3 DTMs
75. tring terminator s system status numerical data requested by commands messages DTM 151 GPIB User s Manual Serial bit rate System orientation Fiber optic cable On board switches Analog outputs IEEE 488 functions GPIB connector 16 rates switch selected 50 110 134 5 150 200 300 600 900 1050 1200 1800 2000 2400 4800 9600 19200 baud Group3 Communication Loop G3CL using serial ports simple loop for 31 devices no multiplexer required GPIB with IEEE 488 option Hewlett Packard HFBR 3500 60 meters max Fiber optic repeater available for extended communications serial baud bit rate selection load defaults device address filtering string terminators data format service request enable EOI enable dc output instantaneous field analog full scale output 3V nominal source impedance 1000Q accuracy 10 bandwidth 3kHz at 3dB rolloff 3 pole 60dB decade ac output rectified analog of time varying ac field frequency response 8Hz to 3kHz at 3dB points time constant 0 2 seconds average responding delivers rms value of sinusoidal field full scale output 3V nominal source impedance 1000Q accuracy 12 SH1 source handshake capability AH1 acceptor handshake capability T5 talker basic talker serial poll talk only mode unaddressed to talk if addressed to listen TEO no address extension talker capability L4 listener basic listener unaddressed to listen if addressed to ta
76. und point Connection can be made to the case by inserting an appropriate lug or terminal under the head of one of the rear panel fixing screws Further protection from transient interference can be obtained by using model PS12D7 power supply in place of the usual plugpack supplied with the teslameter and by installing the Group3 ferrite kit part no 11000036 See section 3 9 of this manual For electrical safety the case of the L version must be grounded through the third wire of the power input cord 3 8 INSTALLING THE PANEL MOUNT OPTION Model DTM 151 PG is supplied fitted with a special front bezel which has threaded studs to allow panel mounting A panel mount support bracket part 17000058 is included to help support the teslameter Group3 can supply 19 inch wide 2U 3 5 high rack panels to hold one two or three teslameters parts 17000025 17000026 and 17000027 respectively Alternatively the user can mount the teslameter in any panel of thickness up to 3 16 4 76mm Dimensions for the cutout and drilled holes are shown below in Fig 4 To fit the teslameter to the panel first remove the nuts and washers from the bezel studs Push the teslameter through the panel from the front making sure all the studs fit through the small holes While holding the teslameter in place place the support bracket under the teslameter from the rear pushing it up to the panel with the studs through the holes in the bracket Put the flat washer
77. y 6 DAV Data Valid 7 NRFD Not Ready For Data 8 NDAC Not Data Accepted 9 IFC Interface Clear 10 SRQ Service Request 11 ATN Attention 12 SHIELD Cable shield connects to teslameter case 13 DIO5 Data Input Output line 5 14 DIO6 Data Input Output line 6 15 DIO7 Data Input Output line 7 16 DIO8 Data Input Output line 8 17 REN Remote Enable not used in teslameter 18 GND 6 Ground wire of twisted pair with DAV 19 GND 7 Ground wire of twisted pair with NRFD 20 GND 8 Ground wire of twisted pair with NDAC 21 GND 9 Ground wire of twisted pair with IFC 22 GND 10 Ground wire of twisted pair with SRQ 23 GND 11 Ground wire of twisted pair with ATN 24 GND Teslameter logic ground Table 1 GPIB Connector Pin Assignments 3 4 DTM 151 GPIB User s Manual SHIELD SRQ DAV 0104 0102 ATN IFC NRFD EOI DIO3 0101 feo meta Eie STN 12 11 10 9 8 7 6 5 4 3 2 1 24 23 22 21 20 19 18 17 16 15 14 13 gt GND GND GND REN 007 0105 11 9 7 LOGIC GND GND GND DIO8 006 GND 10 8 6 Fig 2 IEEE 488 Standard Connector S 1 2 3 4 5 6 7 8 S2 1 2 3 4 5 6 7 8 Fig 3 Location of Processor Board Switches DTM 151 GPIB User s Manual 3 5 3 5 INTERNAL DIP SWITCH SETTINGS The Processor Board in the DTM is provided with two sets of DIP switches allowing the user to set up teslameter operation an
78. y noisy environments see section 3 12 of this manual Powering the L option teslameter The L option will accept power input from the ac power line Access to the power input terminals of the L option is obtained by taking off the orange cover remove the 3 fixing screws to release the cover Use 3 conductor power cord For safety from electrical shock it is essential to provide a reliable ground connection to the DTM case Make sure the ground wire is connected as shown in Fig 1 Strip about 60 mm 2 5 in of outer jacket from the cord and strip 5 mm 3 16 inch of insulation from the 3 wires Pass the cord through the grommetted hole in the cover Loosen the screw securing the cable clamp and pass the cord through the clamp Tighten the clamp on the outer jacket Terminate the wires and fit links according to the supply voltage as set out in Fig 1 below Replace the orange cover making sure that wires are not pinched in the process For safety reasons do not operate the unit with the cover off Note that input power protection is provided by a thermal fuse wound into the power transformer This fuse will open in the event of transformer overheating rather than on excess current The power input must be connected as shown to include the thermal fuse in the circuit correctly If a fault causes transformer overheating and subsequently the fuse opens the transformer must be replaced with the genuine Group3 part If desired the wiring may be
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