Home

HP 34970A User's Manual

1. sji H O WIRING LOG Slot Number J 100 0200 O 300 Function Comments E za SO Fe S Fe Q Fe S Fe Ore Q FS SATEEN OES z Ore 8 8 S fe 4 LOBI OF S E 4W Sense Channels are paired to Channel n 8 8 ES 5 X Be Refer to the diagrams on page 20 to connect wiring to the module g J Sf Maximum Input Voltage 300 V CAT I 20 AWG Typical S Be Maximum Input Current 50 mA 8 Maximum Switching Power 2 W ioe Zo z 6 mm T 3 H 90H l leon IJHN0S YM 7 AT 70H3 HT L on HT lzor HT LOHI QOOOOWQDOGOOO ee 0 YJXJTIdLINW G35y TSNNVHD 9L CHLYVS L0599 Z067 Z WARNING To prevent electrical shock use only wire that is rated for the highest voltage applied to any channel Before removing a module cover turn off all power to external I devices connected to the module 167 Chapter 4 Features and Functions HP 34903A 20 Channel Actuator HP 34903A 20 Channel Actuator This module contains 20 independent SPDT Form C latching relays Screw terminals on the module provide access to the Normally Open Normally Closed and Common contacts for each switch This module does not connect to the internal DMM A breadboard area is provided n
2. A 2 ae 2 Row 4 Me Wy Col 1 ss S9 ss Col8 eee k p gt 8 Rows 8 Columns lt l IN wee Col1 ss 99 se Col8 KN NS aee N 2 Row1 EN y y l pn 3 Row 4 Matrix Module 2 389 Chapter 8 Tutorial RF Signal Multiplexing RF Signal Multiplexing A special type of multiplexer is the RF multiplexer This type of multiplexer uses special components to maintain a 50 or 75Q impedance in the signal line being switched In a test system these switches are often used to route a test signal from a signal source to the device under test The switches are bi directional The diagram below shows two examples of a 4 to 1 channel RF multiplexer in a test system Test 1 Source 1 Signal Test 2 External Ce Source 2 Generator o Test 3 Power Meter o c3 Source 3 o c Test 4 o c3 Source 4 i a a aT Oo 4 Te ee ee 4 4 x 1 Multiplexer 4x 1 Multiplexer By using patch cables you can expand RF multiplexers to provide additional test inputs or outputs For example you can combine two 4 to 1 multiplexers to create a 7 to 1 multiplexer as shown below Test 1 f ET E o Test 2 Oscilloscope o Test 3 l OE i Patch Cable je ES E EA 4 4 x 1 Multiplexer DEA O 1 4x 1 Multiplexer On the HP 34905A 509 and HP 34906A 759 RF multiplexers you can close onl
3. ell fa WIRING LOG Slot Number J 100 200 O 300 EH Row Name Comments Column Name Comments 1 2 3 4 5 6 7 8 Gta y X ot o Example Channel 32 represents Row 3 and Column 2 Sre 5 H Refer to the diagrams on page 20 to connect wiring to the module Slt 3 i SIEF oF Maximum Input Voltage 300 V CAT 1 20 AWG Typical SiS Maximum Input Current 1 A Maximum Switching Power 50 W ENA 6 mm Ja S Es D s SFs SEa 5 ofj iN Xx ES m gt n 8 8 8 8 4 a ee x 2 ooe ooge o L aad A WARNING To prevent electrical shock use only wire that is rated for the highest voltage applied to any channel Before removing a module cover turn off all power to external j devices connected to the module 171 Chapter 4 Features and Functions HP 34905A 6A Dual 4 Channel RF Multiplexers HP 34905A 6A Dual 4 Channel RF Multiplexers These modules consist of two independent 4 to 1 multiplexers The channels in each bank are organized in a tree structure to provide high isolation and low VSWR Both banks have a common earth ground This module does not connect to the internal DMM You can connect your signals directly to the o
4. B This command redefines the scan list when executed Default parameters are shown in bold 187 Chapter 5 Remote Interface Reference SCPI Command Summary Voltage Configuration Commands see page 223 for more information CONFigure VOLTage DC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe VOLTage DC RANGe lt range gt MIN MAX lt ch_list gt VOLTage DC RANGe lt ch_list gt MIN MAX VOLTage DC RANGe AUTO OFF ON lt ch_list gt VOLTage DC RANGe AUTO lt ch_list gt SENSe VOLTage DC RESolution lt resolution gt MIN MAX lt ch_list gt VOLTage DC RESolution lt ch_list gt MIN MAX SENSe VOLTage DC APERture lt time gt MIN MAX lt ch_list gt VOLTage DC APERture lt ch_list gt MIN MAX VOLTage DC NPLC 0 02 0 2 1 2 10 20 100 200 MIN MAX lt ch_list gt VOLTage DC NPLC lt ch_list gt MIN MAX IMPedance AUTO OFF ON lt ch_list gt IMPedance AUTO lt ch_list gt SENSe ZERO AUTO OFF ONCE ON lt ch_list gt ZERO AUTO lt ch_list gt CONFigure VOLTage AC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe VOLTage AC RANGe
5. T ee eeg oo E s ale et EDE VM Complete OUT Ext Trig IN 64 Chapter 3 System Overview Measurement Input The Multifunction Module The multifunction module HP 34907A adds two additional measurement input capabilities to the system digital input and event totalize The multifunction module also contains a dual voltage output DAC which is described in more detail on page 68 Digital Input The multifunction module has two non isolated 8 bit input output ports which you can use for reading digital patterns You can read the live status of the bits on the port or you can configure a scan to include a digital read Each port has a separate channel number on the module and contains 8 bits You can combine the two ports to read a 16 bit word 2 Bito 8 A Port 1 LSB PD Channel 01 2 Digital Bit7 Input Bito B 8 2 2 Port 2 MSB S 7 2 Channel 02 2 Bit7 Z 65 Chapter 3 System Overview Measurement Input Totalizer The multifunction module has a 26 bit totalizer which can count pulses at a 100 kHz rate You can manually read the totalizer count or you can configure a scan to read the count IN 26 Bits N lt 7 Totalize gt Channel 03 2 Gate Gate V e You can configure the totalizer to count on the rising edge
6. Applies to dc voltage measurements only Input Resistance Input Resistance Input Resistance Setting 100 mV 1 V 10 V ranges 100 V 300 V ranges Input R Auto OFF 10 Ma 10 Ma Input R Auto ON gt 10 Ga 10 MQ e Theinstrument selects 10 MQ fixed input resistance on all dc voltage ranges when the measurement function is changed or after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the input resistance setting e Front Panel Operation First select the dc voltage function on the active channel Then go to the Advanced menu and select 10 MQ fixed resistance for all dc voltage ranges or gt 10 G2 The default is 10 MQ INPUT R gt 10 G 113 Chapter 4 Features and Functions Voltage Measurement Configuration e Remote Interface Operation You can enable or disable the automatic input resistance mode on the specified channels With AUTO OFF default the input resistance is fixed at 10 MQ for all ranges With AUTO ON the input resistance is set to gt 10 GQ for the three lowest dc voltage ranges The MEASure and CONFigure commands automatically select AUTO OFF INPUT IMPEDANCE AUTO ON 103 AC Low Frequency Filter The instrument uses three different ac filters which enable you to either optimize low frequency accuracy or achieve faster ac settling times The instrument selects the slow medium
7. Configure the totalizer to count on the rising edge default positive or falling edge negative of the input signal The totalizer channel is numbered s03 where s represents the slot number The SLOP query returns the edge selection Returns NEG or POS SENSe TOTalize CLEar IMMediate lt ch_list gt Immediately clear the count on the specified totalizer channels The totalizer channel is numbered s03 wheres is the slot number SENSe TOTalize DATA lt ch_list gt Read the count on the specified totalizer channels If you have selected the RRESet parameter in the TOT TYPE command then the TOT DATA command will reset the count to 0 after it is read The count is reset regardless of whether the specified channels are in the scan list or even whether a scan is in progress The maximum count is 67 108 863 226 1 The count rolls over to 0 after reaching the maximum allowed value The output from this command is affected by the FORMat READing commands see Reading Format Commands on page 231 257 Chapter 5 Remote Interface Reference Digital Output Commands Digital Output Commands SOURce DIGital DATA BYTE WORD lt data gt lt ch_list gt DIGital DATA BYTE WORD lt ch_list gt Output an 8 bit byte or 16 bit word digital pattern to the specified digital output channels Note that you cannot configure a port for output
8. DIAGnostic RELay CYCLes lt ch_list gt Query the cycle count on the specified channels In addition to the channel relays you can also query the count on backplane relays and bank relays Note that you cannot control the state of these relays from the front panel but you can query the count For more information on channel numbering and layout refer to Module Overview starting on page 163 DIAGnostic RELay CYCLes CLEar lt ch_list gt Reset the de count on the specified channels Note that the instrument must be unsecured to reset the cycle count to unsecure the instrument see the calibration section on page 292 294 Chapter 5 Remote Interface Reference Service Related Commands RST Reset the instrument to the F actory configuration See Factory Reset State on page 160 in chapter 4 for a complete listing of the instrument s Factory Reset state This command is equivalent to selecting FACTORY RESET from the front panel Sto Rcl Menu SYSTem PRESet Preset the instrument to a known configuration See Instrument Preset State on page 161 in chapter 4 for a complete listing of the instrument s preset state This command is equivalent to selecting PRESET from the front panel Sto Rcl Menu SYSTem CPON 100 200 300 ALL Reset the module in the specified slot to its power on state CPON means card power on To reset all three slots specify ALL SYSTem VERSion Query the i
9. Enable bits in the enable register in this register group The selected bits are then reported to the Status Byte A cLs clear status will not clear the enable register but it does clear all bits in the event register A STATus PRESet clears all bits in the enable register To enable bits in the enable register you must write a dedmal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The ENABle query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the STATus ALARm ENABle command SYSTem ALARm Read the alarm data from the alarm queue one alarm event is read and deared each time this command is executed See the diagram on page 251 for more details on the output format 289 Chapter 5 Remote Interface Reference Status System Commands Standard Operation Register Commands See the table on page 285 for the register bit definitions STATus OPERation CONDition Query the condition register in this register group This is a read only register and bits are not cleared when you read the register Note that a RST Factory Reset command may set the Configuration Change bit bit 8 in the condition register A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus OPERation EVENt Query the event register in this register group
10. Frequency Configuration Commands See also Frequency Measurement Configuration in chapter 4 starting on page 118 SENSe FREQuency RANGe LOWer 3 20 200 MIN MAX lt ch_list gt FREQuency RANGe LOWer lt ch_list gt MIN MAX Specify the lowest frequency expected in the input signal for frequency measurements on the specified channels The instrument selects a slow medium default or fast measurement timeout based on the frequency you specify MIN 3 Hz MAX 200 Hz The Low query returns the timeout setting on the specified channels Returns 3 20 or 200 225 Chapter 5 Remote Interface Reference Scanning Overview Scanning Overview See also Scanning in chapter 4 starting on page 74 The instrument allows you to combine a DMM ether internal or external with multiplexer channels to create a scan During a scan the instrument connects the DMM to the configured multiplexer channels one at a time and makes a measurement on each channel Any channel that can be read by the instrument can also be included in ascan This includes any combination of temperature voltage resistance current frequency or period measurements on multiplexer channels A scan can also include a read of a digital port or a read of the totalizer count on the multifunction module Rules for Scanning e Before you can initiate a scan you must set up a scan list to include all des
11. Note Current measurements are allowed only on channels 21 and 22 on the HP 34901A multiplexer module Configure the specified channels for dc or ac current measurements but do not initiate the scan Note that this command also redefines the scan list For ac measurements the resolution is actually fixed at 642 digits the resolution parameter only affects the number of digits shown on the front panel 212 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands CONFigure FREQuency CONFigure PERiod lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for frequency or period measurements but do not initiate the scan Note that this command also redefines the scan list CONFigure DIGital BYTE lt scan_list gt Configure the instrument to read the specified digital input channels on the multifunction module but do not initiate the scan Note that this command also redefines the scan list The digital input channels are numbered s01 LSB and s02 MSB where s is the slot number Note that if you include both digital input channels in the scan list the instrument will read data from both ports simultaneously with the same time stamp This will allow you to externally combine the two 8 bit value into one 16 bit value CONFigure TOTalize READ RRESet lt scan_list gt Configure the instrument to rea
12. Relay Life and Preventative Maintenance The HP 34970A Relay Maintenance System automatically counts the cycles on each relay in the instrument and stores the total count in non volatile memory on each switch module Use this feature to track relay failures and predict system maintenance requirements For more information on using this feature refer to Relay Cycle Count on page 147 Relays are electromechanical devices which are subject to wear out failure modes The life of a relay or the number of actual operations before failure is dependent upon how it is used applied load switching frequency and environment You can use the graphs shown in this section to estimate relay lifetimes for your application Additional background information is also provided to give you a better understanding of relay wear out mechanisms In general relay lifetimes depend heavily upon the signals that are being switched and the types of measurements being performed e Switching typical signal levels will result in relay lifetimes from 1 000 000 to 10 000 000 operations e High power switching gt 25 rating or high voltage switching gt 100V applications will yield relay lifetimes from 100 000 to 1 000 000 operations e Low voltage switching lt 30V and low current switching lt 10 mA applications will yield relay lifetimes to 10 000 000 operations e RF switching applications seldom exhibit relay lifetimes exceeding 1 000 000 ope
13. Decimal Bit Number Value Definition 0 Alarm 1 1 Alarm occurred on Alarm 1 1 Alarm 2 2 Alarm occurred on Alarm 2 2 Alarm3 4 Alarm occurred on Alarm 3 3 Alarm 4 8 Alarm occurred on Alarm 4 4 Queue Empty 16 Alarm queue status 0 empty 1 not empty 5 Queue Overflow 32 Alarm data lost due to alarm queue overflow 6 Not Used 64 Returns 0 J J 4 15 Not Used 32768 Returns 0 The Condition Register implements only bit 4 The Alarm event register is cleared when e You execute a cLs clear status command e You query the event register using the STATus ALARm EVENt command The Alarm enable register is cleared when e You turn on the power PSc does not apply e You execute the STATus PRESet command e You execute the STATus ALARm ENABle 0 command 284 Chapter 5 Remote Interface Reference The SCPI Status System The Standard Operation Register The Standard Operation register group is used to report when the instrument is scanning Any or all of these conditions can be reported to the Standard Operation summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the STATus OPER ENABle command Bit Definitions Standard Operation Register Decimal Bit Number Value Definition 0 Not Used 1 Returns 0 1 Not Used 2 Returns 0 2 Not Use
14. Measurement In put HP 34901A 20 Channel Mux with T C Scanning and direct measurement of Compensation temperature voltage resistance frequency and current HP 34901A only using the HP 34902A 16 Channel Reed Mux with T C internal DMM Compensation HP 34908A 40 Channel Single Ended Mux Scanning and direct measurement of with T C Compensation temperature voltage and resistance using the internal DMM HP 34907A Multifunction Module Digital Input Event Counting Signal Routing HP 34901A 20 Channel Mux with T C Multiplexing of signals to or from external Compensation instruments HP 34902A 16 Channel Reed Mux with T C Compensation HP 34908A 40 Channel Single Ended Mux with T C Compensation HP 34904A 4x8 Matrix Switch 32 Crosspoint Matrix switching HP 34905A Dual 4 Channel RF Mux 509 502 high frequency applications lt 2 GHz HP 34906A Dual 4 Channel RF Mux 759 75a high frequency applications lt 2 GHz Control Output HP 34903A 20 Channel Actuator General purpose switching and control using Form C SPDT switches HP 34907A Multifunction Module Digital Output Voltage DAC Outputs 54 Chapter 3 System Overview Data Acquisition System Overview System Cabling The plug in modules have screw terminal connectors to make it easy to connect your system cabling The type of cabling that you use to connect your signals transducers and sensors to the module is c
15. Q PON 100 200 300 ALL SYSTem RROr E SYSTem ALARm A V SYSTem VERSion TST Default parameters are shown in bold 197 Chapter 5 Remote Interface Reference SCPI Command Summary Interface Configuration Commands see page 269 for more information SYSTem INTerface GPIB RS232 SYSTem LOCal SYSTem REMote SYSTem RWLock Status System Commands see page 286 for more information SIB SRE lt enable_value gt SRE STATus QUEStionable CONDition QUEStionable EVENt QUEStionable ENABle lt enable_value gt QUEStionable ENAB1le ry ry ESR ESE lt enable_value gt ESE STATus ALARm CONDition ALARm EVENt ALARm ENABle lt enable_value gt ALARm ENAB1le fl Fl STATus OPI OPI OPT OPI Ration CONDition Ration EVENt Ration ENABle lt enable_value gt Ration ENABle Fl Fl Fl Gi DATA POINts EVENt THReshold lt num_rdgs gt EVENt THReshold STATus PRESet CLS PSC 0 1 PSC OPC 198 Chapter 5 Remote Interface Reference SCPI Command Summary Calibration Commands see page 292 for more information CALibration CALibration COUNt CALibration ECure CODE lt new_code gt SECure STATe OFF ON lt code gt SECure STATe n CALibration STRin
16. Measurement Noise Rejection l AC CMRR 70 dB Measurement Considerations Frequency and Period All frequency counters are susceptible to error when measuring low voltage low frequency signals Shielding inputs from external noise pickup is critical for minimizing measurement errors 1 300 Vrms isolation voltage ch ch ch earth 2 For frequencies below 100 Hz slow AC filter specified for sinewave input only 3 For 1 kQ unbalance in LO lead 4 Maximum reading rates for 0 01 of ac step additional error Additional settling delay required when input dc level varies 5 612 digits 22 bits 512 digits 18 bits 41 2 digits 15 bits 6 For external trigger or remote operation using default settling delay Delay Auto 7 Maximum limit with default settling delays defeated 8 For fixed function and range readings to memory scaling and alarms turned off 407 Chapter 9 Specifications Measurement Rates and System Characteristics E Measurement Rates and System Characteristics Single Channel Measurement Rates 7 System Characteristics Scan Triggering Scan Count Scan Interval Channel Delay External Trig Delay External Trig Jitter 1 to 50 000 or continuous 0 to 99 hours 1 ms step size 0 to 60 seconds channel 1 ms step size lt 5 ms With Monitor On lt 200 ms lt 2ms Alarms Alarm Outputs 4 TTL compatible Selectable TTL logic HI or LO on Fail Latency 5 ms typical
17. To configure the instrument to recall the power down state or issue a Factory Reset when power is restored select from the following PWR ON LAST PWR ON RE SE T e Remote Interface Operation Use the following commands to store and recall instrument states state 0 is the state of the instrument at power down SAV 01112131415 RCL 0 1 2131415 Toassign a name toa stored state to be recalled from the front panel send the following command From the remote interface you can only recall a stored state using a number 0 through 5 MEM STATE NAME 1 TEST_RACK_1 To configure the instrument to automatically issue a Factory Reset RST command when power is restored send the following command MEMory STATe RI ECall AUTO OFF 141 Chapter 4 Features and Functions System Related Operations Error Conditions When the front panel ERROR annunciator turns on one or more command syntax or hardware errors have been detected A record of up to 10 errors is stored in the instrument s error queue See chapter 6 for a complete listing of the errors Errors are retrieved in first in first out FIFO order The first error returned is the first error that was stored Errors are cleared as you read them When you have read all errors from the queue the ERROR annunciator turns off and the errors are cleared The instrument beeps once each time an error is generated
18. UNIT TEMPerature C F K lt ch_list gt EMPerature lt ch_list gt SENSe TEMPerature TRANsducer YPE TCouple RTD FRTD THERmistor DEF lt ch_list gt YPE lt ch_list gt SENSe TEMPerature TRANsducer TCouple TYPE B E J K N R S T lt ch_list gt TCouple TYPE lt ch_list gt TCouple CHECk ieee ION lt ch_list gt TCouple CHECk lt ch_list gt SENSe TEMPerature TRANsducer TCouple RJUNction TYPE INTernal EXTernal FIXed lt ch_list gt TCouple RJUNction TYPE lt ch_list gt TCouple RJUNction eae a MIN MAX lt ch_list gt TCouple RJUNction lt ch_list gt SENSe TEMPerature RJUNction lt ch_list gt SENSe EMPerature TRANSducer RTD TYPE 85 91 lt ch_list gt RTD TYPE lt ch_list gt R A REFerence lt reference gt lt ch_list gt RTD RESistance REFerence lt ch_list gt SENSe EMPerature TRANSducer FRID TYPE 85 91 lt ch_list gt FRID TYPE lt ch oe ee eee ee REFerence lt reference gt lt ch_list gt FRTD RESistance REFerence lt ch_list gt SENSe TEMPerature TRANsducer THERmistor TYPE 2252 5000 10000 lt ch_list gt HERmistor TYPE lt ch_list gt SENSe EMPerature NPLC 0 02 0 2 1 2 10 20 100 200 MIN MAX lt ch_list gt EMPerature NPLC lt ch_list gt MIN MAX
19. the FORMat READing commands do not apply to monitor readings Returns a number in the form 2 61920000E 01 238 Chapter 5 Remote Interface Reference Scanning With an External Instrument Scanning With an External Instrument If your application doesn t require the built in measurement capabilities of the HP 34970A you can order it without the internal DMM In this configuration you can use the system for signal routing or control applications If you install a multiplexer plug in module you can use the system for scanning with an external instrument Tocontrol scanning with an external instrument two control lines are provided When the HP 34970A and the external instrument are properly configured you can synchronize a scan sequence between the two Channel Closed OUT Ext Trig IN HP 34970A External DMM mp CST if megy o0 E nii el ale EDE LE J HAAS U L VM Complete OUT Ext Trig IN 239 Chapter 5 Remote Interface Reference Scanning With an External Instrument ROUTe SCAN lt scan_list gt SCAN Select the channels to be included in the scan list To start the scan use the INITiate Of READ command Toremove all channels from the scan list send ROUT SCAN The SCAN query
20. 260 Chapter 5 Remote Interface Reference State Storage Commands State Storage Commands The instrument has six storage locations in non volatile memory to store instrument states The locations are numbered 0 through 5 The instrument uses location 0 to automatically hold the state of the instrument at power down You can also assign a name to each of the locations 1 through 5 for use from the front panel SAV 0 1 2 3 4 5 Store Save the current instrument state in the specified storage location Any state previously stored in the same location is overwritten no error is generated e You can store the instrument state in any of the six locations However you can only recall a state from a location that contains a previously stored state You can use location O to store a sixth instrument state However keep in mind that location 0 is automatically overwritten when power is cycled e Theinstrument stores the state of all modules including all channel configurations scanning setups alarm values and scaling values e A Factory Reset RST command does not affect the configurations stored in memory Once a state is stored it remains until it is overwritten or specifically deleted RCL 0 1 2 3 4 5 Recall the instrument state stored in the specified storage location You cannot recall the instrument state from a storage location that is empty or was deleted When shipped from the factory sto
21. 303 305 306 307 Chapter 6 Error Messages Instrument Errors Module not able to perform requested operation A command was received which is not valid for the specified module This error is most commonly generated when you send a command intended for the multifunction module to a switching module Not able to perform requested operation The requested operation is not valid for the specified channel You may have tried to a configure a channel for current measurements valid only on channels 21 and 22 on the HP 34901A module Or you may have tried to configure scaling on a module that does not connect to the internal DMM Part of a 4 wire pair For 4 wire resistance measurements the instrument automatically pairs channel n with channel n 10 84901A or n 8 34902A to provide the source and sense connections To change the configuration on the upper channel in a 4 wire pair you must first reconfigure the lower channel to a measurement function other than 4 wire resistance Incorrectly configured ref channel For thermocouple measurements using an external reference the instrument automatically reserves channel 01 on the multiplexer in the lowest slot as the reference channel Before configuring a thermocouple channel with an external reference you must configure the reference channel channel 01 for a thermistor or RTD measurement This error is also generated if you change the function on the reference channel channel 0
22. 6 Alarm Number Reported 1 2 3 or 4 251 Chapter 5 Remote Interface Reference Alarm System Overview Alarm Output Commands Four TTL alarm outputs are available on the rear panel Alarms connector You can use these hardware outputs to trigger external alarm lights sirens or send a TTL pulse to your control system Each alarm output line represents the logical OR of all channels assigned to that alarm number an alarm on any of the associated channels will pulse the line OUTPut ALARm MODE LATCh TRACk ALARm MODE Select the configuration of the four alarm output lines the configuration applies to all four alarm output lines In the LATCh mode default the corresponding output line is latched true when the first alarm occurs and remains asserted until you clear it by initiating a new scan or cycling power In the TRACk mode the corresponding output line is asserted only when a reading crosses a limit and remains outside the limit When a reading returns to within limits the output line is automatically cleared The MODE query returns the alarm output configuration Returns LATC or TRAC OUTPut ALARm SLOPe NEGative POSitive ALARm SLOPe Select the slope of the pulse from the alarm outputs the selected configuration is used for all four outputs If you select NEG default OV TTL low indicates an alarm If you select Pos 5V TTL high indicates an alarm The
23. Channel n source is automatically paired with Channel n 10 sense on the HP 34901A or Channel n 8 sense on the HP 34902A Ranges 100 1k 10k 100k 1 M 10 M 100 MQ RTD Types 0 00385 0 00391 21 Utility Utility Chapter 1 Quick Start To Set the Time and Date To Set the Time and Date All readings during a scan are automatically time stamped and stored in non volatile memory In addition alarm data is time stamped and stored in a separate non volatile memory queue Set the time of day Use Cl and D to select the field to modify and turn the knob to change the value You can also edit the AM PM field TIME 03 45 PA Set the date Use Cl and L to select the field to modify and turn the knob to change the value JUN 01 1991 Measure i Chapter 1 Quick Start To Configure a Channel for Scanning To Configure a Channel for Scanning Any channel that can be read by the instrument can also be included in a scan This includes readings on multiplexer channels a read of a digital port or a read of the count on a totalizer channel Automated scanning is not allowed with the RF multiplexer matrix actuator digital output or voltage output DAC modules Select the channel to be added to the scan list Turn the knob until the desired channel is shown on the right side of front panel display The channel number is a three digit number the left most digit represents the slo
24. For PLC lt 1 10092 2 0 ms 1002 1 0 ms 1 ka 2 0 ms 1 ka 1 0 ms 10 ka 2 0 ms 10 ka 1 0 ms 100 ka 25 ms 100 ka 20 ms 1 Ma 30 ms 1 Ma 25 ms 10 Ma 200 ms 10 Ma 200 ms 100 Ma 200 ms 100 Ma 200 ms AC Voltage AC Current for all ranges AC Filter Channel Delay Slow 3 Hz 7 0 sec Medium 20 Hz 1 0 sec Fast 200 Hz 120 ms Frequency Period AC Filter Channel Delay Slow 3 Hz 0 6 sec Medium 20 Hz 0 3 sec Fast 200 Hz 0 1 sec Digital Input Totalize Channel Delay 0 sec 89 Chapter 4 Features and Functions Scanning e Front Panel Operation CH DELAY AUTO e Remote Interface Operation The following command enables an automatic channel delay on channel 01 ROUT CHAN DELAY AUTO ON 101 Selecting a specific channel delay using the ROUTe CHANnel DELay command disables the automatic channel delay Viewing Readings Stored in Memory During a scan the instrument automatically adds a time stamp to all readings and stores them in non volatile memory Readings are stored only during a scan You can read the contents of memory at any time even during a scan e You can store up to 50 000 readings in non volatile memory during a scan From the front panel you can view the last 100 readings and all of the readings are available from the remote interface If memory overflows the MEM annunciator will turn on a status regi
25. From the front panel only you can specify whether you want to use binary or decimal format USE DECIMAL USE BINARY e Remote Interface Operation From the remote interface you can read an 8 bit byte from one port or a 16 bit word from both ports using the following commands If you are going to read both ports simultaneously you must send the command to port 01 and neither port can be included in the scan list wn ENS DIG DATA BYTE 302 Read port 02 ENS DIG DATA WORD 301 Read both ports together 0p To redefine the scan list to include a digital read 8 bit read only send the following command CONF DIG BYTE 302 Add port 02 read to scan list 134 Chapter 4 Features and Functions Totalizer Operations Totalizer Operations The multifunction module has a 26 bit totalizer which can count TTL pulses at a 100 kHz rate You can manually read the totalizer count or you can configure a scan to read the count e The totalizer channel is numbered s03 wheres represents the slot number e You can configure the instrument to count on the rising edge or falling edge of the input signal e You can control when the totalizer actually records counts by providing a gate signal G and G terminals on the module A TTL high signal applied to the G terminal enables counting and a low signal disables counting A TTL low signal applied to the G terminal enables counting
26. Resistance Configuration Commands See also Resistance Measurement Configuration in chapter 4 starting on page 115 SENSe RESistance OCOMpensated OFF ON lt ch_list gt RESistance OCOMpensated lt ch_list gt FRESistance OCOMpensated OFF ON lt ch_list gt FRESistance OCOMpensated lt ch _list gt Disable or enable offset compensation for resistance measurements Once enabled offset compensation is applied to both 2 wire and 4 wire resistance measurements The default is OFF The ocom query returns the offset compensation setting on the spedfied channels Returns O OF F or 1 ON Current Configuration Commands See also Current Measurement Configuration in chapter 4 starting on page 116 Note Current measurements are allowed only on channels 21 and 22 on the HP 34901A multiplexer module SENSe CURRent AC BANDwidth 3 20 200 MIN MAX lt ch_list gt CURRent AC BANDwidth lt ch_list gt MIN MAX Specify the lowest frequency expected in the input signal for ac current measurements on the specified channels The instrument selects the slow medium default or fast ac filter based on the frequency you specify MIN 3 Hz MAX 200 Hz The BAND query returns the ac filter setting on the specified channels Returns 3 20 or 200 224 Chapter 5 Remote Interface Reference Frequency Configuration Commands
27. See also Alarm Limits in chapter 4 starting on page 122 The instrument has four alarms which you can configure to alert you when a reading exceeds specified limits on a channel during a scan You can assign a high limit a low limit or both to any configured channel in the scan list You can assign multiple channels to any of the four available alarms numbered 1 through 4 For example you can configure the instrument to generate an alarm on the Alarm 1 output when a limit is exceeded on any of channels 103 205 or 320 You can also assign alarms to channels on the multifunction module For example you can generate an alarm when a specific bit pattern or bit pattern change is detected on a digital input channel or when a spedfic count is reached on a totalizer channel With the multifunction module the channels do not have to be part of the scan list to generate an alarm For complete details see Using Alarms With the Multifunction Module on page 130 Alarm data can be stored in one of two locations depending on whether a scan is running when the alarm occurs 1 If an alarm event occurs on a channel as it is being scanned then that channel s alarm status is stored in reading memory as the readings are taken Each reading that is outside the specified alarm limits is logged in memory You can store up to 50 000 readings in memory during a scan You can read the contents of reading memory at any time even during a scan
28. User s Guide Part Number 34970 90002 October 1997 For Safety information Warranties and Regulatory information see the pages behind the Index Copyright Hewlett Packard Company 1997 All Rights Reserved HP 34970A Data Acquisition Switch Unit The HP 34970A combines precision measurement capability with flexible signal connections for your production and development test systems Three module slots are built into the rear of the instrument to accept any combination of data acquisition or switching modules The combination of data logging and data acquisition features makes this instrument a versatile solution for your testing requirements now and in the future Convenient Data Logging Features Direct measurement of thermocouples RTDs thermistors dc voltage ac voltage resistance dc current ac current frequency and period Interval scanning with storage of up to 50 000 time stamped readings Independent channel configuration with function Mx B scaling and alarm limits available on a per channel basis Intuitive user interface with knob for quick channel selection menu navigation and data entry from the front panel Portable ruggedized case with non skid feet HP BenchLink Data Logger Software for Microsoft Windows included Flexible Data Acquisition Switching Features 61 digit multimeter accuracy stability and noise rejection Up to 60 channels per instrument 120 single ended channels Reading
29. f RRB IRR f ii AEN narea LHH H HLL Front Rear bottom view To remove the rubber bumper stretch a corner and then slide it off 30 Chapter 1 Quick Start To Rack Mount the Instrument To rack mount two instruments side by side order lock link kit 5061 9694 and flange kit 5063 9212 Be sure to use the support rails inside the rack cabinet To install one or two instruments in a sliding support shelf order shelf 5063 9255 and slide kit 1494 0015 for a single instrument also order filler panel 5002 3999 31 Front Panel Overview Front Panel Overview This chapter introduces you to the front panel keys and menu operation This chapter does not give a detailed description of every front panel key or menu operation It does however give you a good overview of the front panel menu and many front panel operations See chapter 4 Features and Functions starting on page 71 for a complete discussion of the instrument s capabilities and operation This chapter is divided into the following sections e Front Panel Menu Reference on page 35 e To Monitor a Single Channel on page 37 e To Set a Scan Interval on page 38 e To Apply Mx B Scaling to Measurements on page 39 e To Configure Alarm Limits on page 40 e To Read a Digital Input Port on page 42 e To Write to a Digital Output Port on page 43 e To Read the Totalizer Count on page 44 e To
30. 1 in the register To report any subsequent events the reading count must first drop below the programmed threshold before reaching the threshold again Once this bit is set it remains set until cleared by the STATus OPER EVENt command or cLs clear status command The THReshold query returns the number of readings currently specified as the memory threshold Miscellaneous Status Register Commands CLS Clear the event register in all register groups This command also clears the error queue and the alarm queue STATus PRESet Clear all bits in the Questionable Data enable register the Alarm enable register and the Standard Operation enable register PSC 0 1 PSC Power On Status Clear Clear the Standard Event enable register and Status Byte condition register at power on Psc 1 When Psc oisin effect these two registers are not cleared at power on The PSC query returns the power on status clear setting Returns 0 do not clear at power on or 1 clear at power on OPC Set the Operation Complete bit bit 0 in the Standard Event register at the completion of the current scan 291 Chapter 5 Remote Interface Reference Calibration Commands Calibration Commands For an overview of the calibration features of the instrument refer to Calibration Overview in chapter 4 starting on page 155 For a more detailed discussion of the instrument s calibrat
31. 361 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in AC Voltage Measurements Many of the errors associated with dc voltage measurements also apply to ac voltage measurements Additional errors unique to ac voltage measurements are described in this section Crest Factor Errors non sinusoidal inputs A common misconception is that since the internal DMM is true RMS its sinewave accuracy specifications apply to all waveforms Actually the shape of the input signal can dramatically affect measurement accuracy A common way to describe signal waveshapes is crest factor Crest factor is the ratio of the peak value to the RMS value of a waveform For a pulse train for example the crest factor is approximately equal to the square root of the inverse of the duty cycle as shown in the table on page 360 In general the greater the crest factor the greater the energy contained in higher frequency harmonics All multimeters exhibit measurement errors that are crest factor dependent Crest factor errors are shown in the specifications in chapter 9 on page 407 Note that the crest factor errors do not apply for input signals below 100 Hz when using the slow ac filter You can estimate the measurement error due to signal crest factor as shown below Total Error Errorsine Errorcrest factor Errorpandwidth Where Errorgine DMM s sinewave accuracy see page 406 ErrOrcrest factor DMM s crest factor see p
32. 91 126 viewing alarm data 126 readings 90 scanned readings 24 Visual Basic example 321 VM Complete signal 95 VOLT AC BANDwidth command 223 voltage DAC output card reset 139 current limitations 139 397 differential errors 398 integral errors 398 resetting 45 simplified schematic 397 writing 45 voltage dividers 385 voltage measurements 113 ac low frequency filter 114 ac settling time 114 VSWR 391 411 WwW Warnings HP 34901A 165 HP 34902A 167 HP 34903A 169 HP 34904A 171 HP 34908A 176 warranty information inside front cover weight product 408 Wheatstone bridge strain 375 wire size gauge 336 wiring log HP 34901A 165 HP 34902A 167 HP 34903A 169 HP 34904A 171 HP 34905A 173 HP 34906A 173 HP 34907A 175 HP 34908A 177 wiring connections ac current 21 ac voltage 21 de current 21 dc voltage 21 frequency 21 period 21 resistance 21 RTDs 21 thermistors 21 thermocouples 21 wiring strain relief 20 wiring strip length 20 Write key 48 45 www hp com HP Website 374 X XON XOFF flow mode RS 232 153 Z ZERO AUTO command 105 223 433 DECLARATION OF CONFORMITY according to ISO IEC Guide 22 and EN 45014 Manufacturer s Name Hewlett Packard Company Loveland Manufacturing Center Manufacturer s Address 815 14th Street S W Loveland Colorado 80537 U S A declares that the product Product Name Data Acquisition Switch
33. AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt CURRent AC lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt FREQuency lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt Riod lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt DIGital BYTE lt scan_list gt TOTalize READ RRESet lt scan_list gt lt P ie Monitor Commands see page 237 for more information ROUTe MONitor lt channel gt MONitor ROUTe MONitor STATe OFF ON MONitor STATe ROUTe MONitor DATA B This command redefines the scan list when executed Default parameters are shown in bold 183 Chapter 5 Remote Interface Reference SCPI Command Summary Scan Configuration Commands see page 226 for more information ROUTe SCAN lt scan_list gt SCAN SCAN SIZ a TRIGger SOURce BUS IMMediate EXTernal ALARm1 ALARm2 ALARm3 ALARm4 TIMer SOURce TRIGger TIMer lt seconds gt MIN MAX TIMer TRIGger COUNt lt count gt MIN MAX INFinity COUNt ROUTe CHANnel CHANnel CHANnel CHANnel say lt seconds gt lt ch_list gt ay lt ch_list gt ELay AUTO OFF ON lt
34. Be sure to have access in the project to visa lib or visa32 lib usually found in the c vxipnp or c visa directory 328 Chapter 7 Application Programs Example Programs for C and C C C Example dac_out c dac_out c BR RK RIK A RR E e A AR e E A I A A A A A IA I A I IK Required HP 34907A Multifunction Module in slot 200 VISA library x This program uses the VISA library to communicate with the HP 34970A The program queries slot 200 and displays the response It then resets x the instrument and sends the value voltage to the DAC on channel 205 RRR K k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k kk kk kkk kk kkk kk kkk f include lt visa h gt include lt stdio h gt include lt string h gt define ADDR 9 Set HP IB address for instrument void main ViSession defaultRM Resource manager id ViSession dac Identifies instrument char reply_string 256 String returned from instrument char Visa_address 40 VISA address sent to module double voltage Value of voltage sent to DAC Build the address required to open communication with HP IB card The address format looks like this GPIB0 9 INSTR strcpy Visa_address GPIBO strcat Visa_address ADDR strcat Visa_address INSTR Open communication session with the HP 34970A viOpenDefaultRM amp defaultRM viOpen d
35. For example sending the following command string TRIG SOUR EXT COUNT 10 is the same as sending the following two commands TRIG SOUR EXT TRIG COUNT 10 Usea colon and a semicolon to link commands from different subsystems For example in the following command string an error is generated if you do not use both the colon and semicolon ROUT CHAN DELAY 1 TRIG SOUR EXT Using the MIN and MAX Parameters You can substitute MINimum or MAXimum in place of a parameter for many commands For example consider the following command VOLTage DC RANGe lt range gt MINimum MAXimum lt ch_list gt Instead of selecting a specific range you can substitute MIN to set the range to its minimum value or max to set the range to its maximum value 298 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language Querying Parameter Settings You can query the current value of most parameters by adding a question mark tothe command For example the following command sets the scan count to 10 sweeps TRIG COUN 10 You can query the scan count value by executing TRIG COUN You can also query the minimum or maximum scan count allowed as follows TRIG COUN MIN TRIG COUN MAX SCPI Command Terminators A command string sent to the instrument may be terminated with a lt new line gt character The EEE 488 EOI end or identify message can be used to terminate a comm
36. LHI RIII 3333S ZHI LWOD XAW b7 YNA 173 Sh 26 Bits S UE Chapter 4 Features and Functions HP 34907A Multifunction Module HP 34907A Multifunction Module This module combines two 8 bit ports of digital input output a 100 kHz totalizer and two 12 analog outputs F or greater flexibility you can read digital inputs and the totalizer count during a scan auth Digital Input Output Bit 5 Spies The DIO consists of two 8 bit ports with F Chaney TTL compatible inputs and output The open A drain outputs can sink up to 400 mA From the po 2Bt7 front panel you can read data from only one 8 bit eee input port at a time From the remote interface 2 Port 2 MSB you can read both ports simultaneously as a 3 Channel 02 16 bit word only if neither port isin thescan list 2 Bit 7 Nerd i Totalize Input The 26 bit totalizer can count pulses at a 100 kHz rate You can configure the totalizer to count on the rising edge or falling edge of the input signal Gate disables counting The totalizer only counts when both terminals are enabled Move the Totalize Threshold jumper to the AC position to detect changes through 0 volts Movethejumper to the TTL position factory setting to detect changes through TTL threshold levels 24N gt A TTL high signal applied t
37. MEASure DIGital BYTE lt scan_list gt Configure the instrument to read the specified digital input channels on the multifunction module and immediately sweep through the scan list one time Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot number Note that if you include both digital input channels in the scan list the instrument will read data from both ports simultaneously with the same time stamp This will allow you to externally combine the two 8 bit value into one 16 bit value MEASure TOTalize READ RRESet lt scan_list gt Configure the instrument to read the count on the specified totalizer channels on the multifunction module and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory The totalizer channel is numbered s03 where s represents the slot number To read the totalizer during the scan without resetting the count select the READ parameter To read the totalizer during the scan and reset the count to O after it is read select the RRESet parameter this means read and reset 210 Chapter 5 Remote I
38. NEQ CALCulate COMPare DATA lt data gt lt ch_list gt COMPare DATA lt ch_list gt Specify the digital pattern for comparisons on the specified DIO channels You must specify the digital pattern as a decimal value between 0 and 255 binary data is not accepted The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot number The DATA query returns the comparison pattern as a decimal value 253 Chapter 5 Remote Interface Reference Alarm System Overview CALCulate COMPare MASK lt mask gt lt ch_list gt COMPare MASK lt ch_list gt Specify the mask pattern for comparisons on the specified DIO channels You must specify the mask parameter as a decimal value between 0 and 255 binary data is not accepted Specify 1 s for active bits or O s for don t care bits The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot number The MASK query returns the mask pattern as a decimal value CALCulate COMPare STATe OFF ON lt ch_list gt COMPare STATe lt ch_list gt Disable or enable the comparison mode on the specified DIO channels Note that the specified channels do not have to be part of the scan list to generate an alarm Alarms are evaluated continuously as soon as you enable them Alarms are evaluated constantly on the multifunction module but alarm data i
39. None no flow control XON KOFF factory setting DTR DSR RTS CTS or Modem e None In this mode data is sent and received over the interface without any flow control used When using this method use a slower baud rate lt 9600 baud and avoid sending more than 128 characters without stopping or reading a response e XON XOFF This mode uses special characters embedded in the data stream to control the flow If the instrument is addressed to send data it continues sending data until the XOF F character 13H is received When the XON character 11H is received the instrument resumes sending data e DTR DSR In this mode the instrument monitors the state of the DSR data set ready line on the RS 232 connector When the line goes true the instrument sends data over the interface When the line goes false the instrument stops sending information typically within six characters The instrument sets the DTR line false when the input buffer is almost full approximately 100 characters and releases the line when space is available again e RTS CTS This mode operates the same as the DTR DSR mode but uses the RTS request to send and CTS clear to send lines on the RS 232 connector instead When the CTS line goes true the instrument sends data over the interface When the line goes false the instrument stops sending information typically within six characters The instrument sets the RTS line false when the input b
40. Numeric overflow A numeric parameter was found whose exponent was too large for this command Example CALC SCALE GAIN 1E34000 Too many digits A numeric parameter was found whose mantissa contained more than 255 digits excluding leading zeros Numeric data not allowed The wrong parameter type was found in the command string You may have specified a number where a string or expression was expected or vice versa Examples DISP TEXT 5 0 or ROUT CLOSE 101 Invalid suffix A suffix was incorrectly specified for a numeric parameter You may have misspelled the suffix Example ROUT CHAN DELAY 5 SECS Suffix too long A header suffix is the number that can be appended to the end of some command headers This error is generated if the header suffix contains more than 12 characters Character data not allowed A discrete parameter was received but a character string or a numeric parameter was expected Check the list of parameters to verify that you have used a valid parameter type Examples ROUTE CLOSE CH101 or DISP TEXT TESTING the string must be enclosed in quotes Invalid string data An invalid character string was received Check to see if you have enclosed the character string in quotation marks and verify that the string contains valid ASCII characters Example DISP TEXT TESTING the ending quote is missing String data not allowed A character string was received but i
41. Range al bal ClearContents Clear out row 1 Step through the number of scan sweeps For columnIndex 1 To numberScans Start of scan data Do Wait for instrument to put a reading in memory SendSCPI DATA POINTS Get the number of readings stored points Val GetSCPI Loop Until points gt Remove one reading at a time from memory For Channel 1 To numberChannels SendSCPI DATA REMOVE 1 Request one reading from memory Application ScreenUpdating False Get readings from buffer and store in cell Al Cells 1 1 GetSCPI Parse the string in cell Al and put into row 1 Range al TextToColumns Destination Range al comma True Call routine to organize the data in row 1 into a table makeDataTable Channel columnIndex Range al bal ClearContents Clear out row 1 Application ScreenUpdating True Do Wait for instrument to put another reading in memory SendSCPI DATA POINTS Get the number of readings stored points Val GetSCPI Loop Until points gt 1 Or Channel gt numberChannels Next Channel Next columnIndex ClosePort Close communications on HP IB End Sub Continued on next page 326 Chapter 7 Application Programs Example Programs for Excel 7 0 Sub makeDataTable Channel As Integer columnIndex As Integer This routine will take the parsed data in row 1 for a channel and put it into a table Channel determines the row
42. Remove the 2 Remove the line voltage selector from fuse holder assembly from the rear panel the assembly Fuse 500 mAT for all line voltages HP Part Number 2110 0458 3 Rotate the line voltage selector until the correct voltage appears in the window 4 Replace the fuse holder assembly in the rear panel 100 120 127 220 230 or 240 Vac Verify that the correct line voltage is selected and the power line fuse is good 28 Chapter 1 Quick Start To Adjust the Carrying Handle To Adjust the Carrying Handle To adjust the position grasp the handle by the sides and pull outward Then rotate the handle to the desired position H i gt a 3 rie i TY If J AJ A ta I TT r Bench top viewing positions Carrying position 29 Chapter 1 Quick Start To Rack Mount the Instrument To Rack Mount the Instrument You can mount the instrument in a standard 19 inch rack cabinet using one of three optional kits available Instructions and mounting hardware are included with each rack mounting kit Any HP System IT instrument of the same size can be rack mounted beside the HP 34970A Note Remove the carrying handle and the front and rear rubber bumpers before rack mounting the instrument Siz To remove the handle rotate it to the vertical position and pull the ends outward
43. WI JN ONJW3 IN ON WI IN ONJWI IN ON SOHD 6mm 70H JSOd Nd IWYSNS9 YOLVALIV TSANNVH D OZ H EOHI HILIMS ZOHD 2QOQVQO O VO VOVHVHOVOV2 VO90020202G2 000002020209 WIN ON WD IN ON WD IN ONTW IN ON LOHI 10599 067E that is rated for the highest voltage applied to any channel Before removing a module cover turn off all power to external 1 1 devices connected to the module la A WARNING To prevent electrical shock use only wire 169 Chapter 4 Features and Functions HP 34904A 4x8 Matrix Switch HP 34904A 4x8 Matrix Switch This module contains 32 two wire crosspoints organized in a 4 row by 8 column configuration You can connect any combination of inputs and outputs at the same time This module does not connect to the internal DMM Each crosspoint relay has its own unique channel label representing the row and column For example channel 32 represents the crosspoint connection between row 3 and column 2 as shown below Col 1 Col 2 Col 8 H L H L H L 2 Q Q H E Row 1 H QL Row 2 f H E Row 3 NOY N H L a H AS a Row4 fy LN E Channel 32 12 L Row 3 Column 2 Re y NOTES e You can close multiple channels at the same time on this module 170 Chapter 4 Features and Functions HP 34904A 4x8 Matrix Switch
44. You can read the contents of memory at any time even during a scan Reading memory is not cleared when you read it 74 Chapter 4 Features and Functions Scanning e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan Therefore the contents of memory are always from the most recent scan e While a scan is running the instrument automatically stores the minimum and maximum readings and calculates the average for each channel You can read these values at any time even during a scan e Mx B scaling and alarm limits are applied to measurements during a scan and all data is stored in non volatile memory You can read the contents of reading memory or the alarm queue at any time even during a scan e Inthe Monitor function the instrument takes readings as often as it can on a single channel even during a scan see Single Channel Monitoring on page 93 This feature is useful for troubleshooting your system before a test or for watching an important signal e Ifyou abort a scan that is running the instrument will complete the one measurement in progress the entire scan will not be completed and the scan will stop You cannot resume the scan from where it left off If you initiate a new scan all readings are deared from memory e When you add a multiplexer channel toa scan list that entire module is dedicated to the scan The instrum
45. channel and alarm information are not returned the FORMat READing commands do not apply to monitor readings ROUT MON DATA 94 Chapter 4 Features and Functions Scanning With External Instruments Scanning With External Instruments If your application doesn t require the built in measurement capabilities of the HP 34970A you can order it without the internal DMM In this configuration you can use the system for signal routing or control applications If you install a multiplexer plug in module you can use the system for scanning with an external instrument You can connect an external instrument such as a DMM to the multiplexer COM terminal H Ss Se L a nn H Gs Pe ta ee fe External DMM Input o m cranes EE H 62 Se N Common Terminals ee Et COM _ __ H J 2L To control scanning with an external instrument two control lines are provided When the HP 34970A and the external instrument are properly configured you can synchronize a scan sequence between the two Channel Closed OUT HP 34970A J External DMM Mir eA fT TY a eo E neui HE ey NASAN CELI CELI U O VM Complete OUT Ext Trig IN 95 Chapter 4 Features and Functions Scanning With External Instruments In th
46. does not change the setting 116 Chapter 4 Features and Functions Current Measurement Configuration e Front Panel Operation First select the ac current or ac voltage function on the active channel Then go to the Advanced menu and select the slow filter 3 Hz medium filter 20 Hz or fast filter 200 Hz for the active channel The default is the medium filter LF 3 HZ SLOW Remote Interface Operation Specify the lowest frequency expected in the input signal on the specified channels The instrument selects the appropriate filter based on the frequency you specify see table on previous page The MEASure and CONFigure commands automatically select the 20 Hz medium filter SENS CURR AC BAND 3 221 Select the slow filter 3 Hz 117 Chapter 4 Features and Functions Frequency Measurement Configuration Frequency Measurement Configuration To connect an ac source to the module s screw terminals see page 21 Low Frequency Timeout The instrument uses three different timeout ranges for frequency measurements The instrument selects a slow medium or fast timeout based on the input frequency that you specify for the selected channels Input Frequency Timeout 3 Hz to 300 kHz Slow 1s 20 Hz to 300 kHz Medium 100 ms 200 Hz to 300 kHz Fast 10 ms e Theinstrument selects the medium timeout 20 Hz when the function is changed or after a F actory Reset RST command A
47. each filter will allow up to 100 channels per second However the measurement might not be very accurate since the filter is not fully settled In scanning applications where sample to sample levels vary widely the medium filter 20 Hz will settle at 1 reading per second and the fast filter 200 Hz will settle at 10 readings per second If the sample to sample levels are similar little settling time is required for each new reading Under this specialized condition the medium filter 20 Hz will provide reduced accuracy results at 5 readings per second and the fast filter 200 Hz will provide reduced accuracy results at 50 readings per second Additional settling time may be required when the dc level varies from sample to sample The internal DMM s dc blocking circuitry has a settling time constant of 0 2 seconds This settling time only affects measurement accuracy when dc offset levels vary from sample to sample If maximum measurement speed is desired in a scanning system you may want to add an external dc blocking circuit to those channels with significant de voltages present This circuit can be as simple as a resistor and a capacitor AC Filter Channel Delay Settling Time 200 Hz Fast AUTO 0 12 seconds 20 Hz Medium AUTO 1 second 3 Hz Slow AUTO 7 seconds 200 Hz Fast 0 0 02 seconds 20 Hz Medium 0 0 2 seconds 3 Hz Slow 0 1 5 seconds DC blocking settling time 1 time constant 0 2 seconds
48. forward method to program the instrument for scanning You can select the measurement function range and resolution all in one command All other measurement parameters are set to their default values as shown in the table below Measurement Parameter MEASure and CONFigure Setting Integration Time 1 PLC Input Resistance 10 Mo fixed for all DCV ranges AC Filter 20 Hz medium filter Scan List Redefined when command executed Scan Interval Source Immediate Scan Count 1 Scan Sweep Channel Delay Automatic Delay When you configure a channel using MEASure or CONFigure itis important to note that the previous configuration on that channel is lost For example assume that a channel is configured for dc voltage measurements When you reconfigure that channel for thermocouple measurements the previous range resolution and other measurement attributes are set to their default values 201 Chapter 5 Remote Interface Reference Simplified Programming Overview Using the MEASure Command The MEASure command provides the easiest way to program the instrument for scanning However this command does not offer much flexibility When you execute this command the instrument uses default values for the requested measurement configuration and immediately performs the scan You cannot change any measurement attributes other than function range and resolution before the measurement is taken The results are sent directl
49. lt range gt MIN MAX lt ch_list gt VOLTage AC RANGe lt ch_list gt MIN MAX VOLTage AC RANGe AUTO OFF ON lt ch_list gt VOLTage AC RANGe AUTO lt ch_list gt SENSe VOLTage AC BANDwidth 3 20 200 MIN MAX lt ch_list gt VOLTage AC BANDwidth lt ch_list gt MIN MAX B This command redefines the scan list when executed Default parameters are shown in bold 188 Chapter 5 Remote Interface Reference SCPI Command Summary Resistance Configuration Commands see page 224 for more information CONFigure RESistance lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe RESistance RANGe o MIN MAX lt ch_list gt RESistance RANGe lt ch_list gt MIN MAX J i ea OFF ON lt ch_list gt RESistance RANGe AUTO lt ch_list gt SENSe RESistance RESolution haem aaa reer lt ch_list gt RESistance RESolution lt ch_list gt MIN MAX RESistance APERture a MIN MAX lt ch_list gt RESistance APERture lt ch_list gt MIN MAX RESistance NPLC 0 02 0 2 1 2 10 20 100 200 MIN MAX lt ch_list gt RESistance NPLC lt ch_list gt MIN MAX SENSe RESistance OCOMpensated OFF ON lt ch_list gt RESistance OCOMpensated lt ch_list gt CONFigure FRESistanc
50. readings including alarm data stored in reading memory from the previous scan As alarms are generated they are also logged in an alarm queue which is separate from reading memory Up to 20 alarms can be logged in the alarm queue Reading the alarm queue using the View menu clears the alarms in the queue 41 en Chapter 2 Front Panel Overview To Read a Digital Input Port To Read a Digital Input Port The multifunction module HP 34907A has two non isolated 8 bit input output ports which you can use for reading digital patterns You can read the live status of the bits on the port or you can configure a scan to include a digital read Select the Digital Input port Select the slot containing the multifunction module and continue turning the knob until DIN is displayed channel 01 or 02 Read the specified port You can specify whether you want to use binary or decimal format Once you have selected the number base it is used for all input or output operations on the same port To change the number base 01010101 DIN Binary Display Shown Bit 7 Bit 0 The bit pattern read from the port will be displayed until you press another key turn the knob or until the display times out the DIO READ choice 42 Chapter 2 Front Panel Overview To Write to a Digital Output Port To Write to a Digital Output Port The multifunction module HP 34907A has two non isolated 8 bit input output ports which y
51. required either The count on a totalizer channel is not reset when it is being monitored the Monitor ignores the totalizer reset mode 237 Chapter 5 Remote Interface Reference Single Channel Monitoring Overview ROUTe MONitor lt channel gt MONitor Select the channel to be monitored To turn on the monitor function use the ROUT MON STATE ON command see below The SCAN query returns a list of channel numbers in the SCPI definite length block format The response begins with the character followed by a single character representing the number of succeeding characters to interpret as a length specifier followed by a length specifier representing the number of bytes in the block followed by a block of that many bytes An empty channel list one with no channels selected will be 13 For example the ROUT MON command will return the following if channel 103 is the channel currently being monitored 16 103 ROUTe MONitor STATe OFF ON MONitor STATe Disable default or enable the Monitor function If you do not specify the monitor channel using the ROUT MON command see above the channel displayed on the front panel is used The STAT query reads the state of the monitor function Returns O OFF or 1 ON ROUTe MONitor DATA Read the data from the Monitor function Returns the reading only the units time channel and alarm information is not returned
52. s output buffer but the readings are not stored in reading memory The default DEF transducer type is a J Type thermocouple 207 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands MEASure TEMPerature RTD FRTD 85 91 DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for 2 wire or 4 wire RTD measurements and immediately sweep through the scan list one time Use 85 to spedfy 0 00385 or 91 to specify 0 00391 Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory The default DEF type is 85 x 0 00385 For 4 wire RTD measurements FRTD the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections F or example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel MEASure TEMPerature THERmistor 2252 5000 10000 DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for thermistor measurements and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directl
53. status 276 relative time 87 relay contact protection 385 relay contact resistance 399 relay cycle count clearing 148 estimating relay life 399 reading 147 399 relay life relay maintenance system 399 vs load switched 400 vs relay life 400 relay maintenance system clearing relay count 148 reading relay count 147 399 remote interface HP IB IEEE 488 address selection 46 151 cable 51 connector 5 interface selection 46 151 setting address 150 factory address setting 150 remote interface RS 232 serial baud rate 47 cable 51 flow control 47 parity 47 stop bits 47 RES OCOMpensated command 224 reset mode totalizer 44 76 resistance ladder 384 resistance measurements 2 wire ohms 369 4 wire ohms 369 connections 21 nominal RTD 110 222 offset compensation 115 371 ranges 21 resolution 417 half digit 100 command syntax 216 selecting 101 vs integration time 103 203 result codes modem 274 revision number firmware HP 34970A 146 plug in modules 146 RF cable kits SMB to BNC 173 RF multiplexers insertion loss 391 performance graphs 411 sources of error 391 VSWR 391 RFI radiation 339 ribbon cables 55 RMT annunciator 4 rosette strain gage 374 ROUTe CHAN ADV SOUR command 97 ROUTe CHAN DELay command 88 229 ROUTe CHAN DELay AUTO command 230 ROUTe CHAN FWIRe command 97 243 ROUTe CHAN ADV SOUR command 242 ROUTe CLOSe comman
54. the instrument stores all readings and alarms with the current time and date The instrument stores the time and date information in non volatile memory e When shipped from the factory the instrument is set to the current time and date U S Mountain Time Front Panel Operation TIME 03 45 PM JUN 01 1997 Remote Interface Operation Use the following commands to set the time and date SYST TIME 15 45 00 Set time to 3 45 PM SYST DATE 1997 06 01 Set date to June 1 1997 Internal DMM Disable You can scan through the configured channels using either the internal DMM or an external instrument F or externally controlled scans you must either remove the internal DMM from the instrument or disable it For information on controlling a scan with an external instrumen refer to Scanning With External Instruments on page 95 When shipped from the factory the internal DMM is enabled When you change the state of the internal DMM the instrument issues a Factory Reset RST command A Factory Reset RST command or Instrument Preset SySTem PRI command does not affect the internal DMM configuration Front Panel Operation DMM ENABLED DMM DISABLED Remote Interface Operation INSTrument DMM OFF ON t ESet 145 Chapter 4 Features and Functions System Related Operations Firmware Revision Query The instrument has three microprocessors for control of various i
55. use the following command OUTPut ALARm MODE LATCh TRACk To configure the slope of all four output lines use the following command OUTPut ALARm SLOPe NEGative POSitive 129 Chapter 4 Features and Functions Alarm Limits Using Alarms With the Multifunction Module You can configure the instrument to generate an alarm when a specific bit pattern or bit pattern change is detected on a digital input channel or when a specific count is reached on a totalizer channel These channels do not have to be part of the scan list to generate an alarm Alarms are evaluated continuously as soon as you enable them e The digital input channels are numbered s01 lower byte and s02 upper byte where s represents the slot number The totalizer channel is numbered s03 e Alarms are evaluated continuously on the multifunction module but alarm data is stored in reading memory only during a scan e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan However alarm data stored in the alarm queue from the multifunction module is not cleared Therefore although the contents of reading memory are always from the most recent scan the alarm queue may contain data that occurred during previous scans or while the instrument was not scanning e Front Panel Operation To configure an alarm on a digital input channel choose from the foll
56. you may want to refer to these sections to become familiar with the language before attempting to program the instrument 180 Chapter 5 Remote Interface Reference SCPI Command Summary SCPI Command Summary Throughout this manual the following conventions are used for SCPI command syntax for remote interface programming e Square brackets indicate optional keywords or parameters e Braces enclose parameter choices within a command string e Triangle brackets lt gt enclose parameters for which you must substitute a value e A vertical bar separates multiple parameter choices Rules for Using a Channel List Many of the SCPI commands for the HP 34970A include a scan_list or ch_list parameter which allow you to specify one or more channels The channel number has the form see wheres is the slot number 100 200 or 300 and ce is the channel number You can specify a single channel multiple channels or a range of channels as shown below e The following command configures a scan list to include only channel 10 on the module in slot 300 ROUT SCAN 310 e The following command configures a scan list to include multiple channels on the module in slot 200 The scan list now contains only channels 10 12 and 15 the scan list is redefined each time you send anew ROUTe SCAN command ROUT SCAN 210 212 215 e The following command configures a scan list to include a range of cha
57. 100 0 06 5 Hz 10 Hz 0 30 0 5 0 30 0 5 0 30 0 5 0 035 0 06 10 Hz 5 kHz 0 10 0 5 0 10 0 5 0 10 0 5 0 015 0 06 Additional Low Frequency Error for ACV ACI of reading Additional Error for Frequency Period of reading AC Filter AC Filter AC Filter Frequency Slow Medium Fast Frequency 6 2 Digits 5 Digits 41 2 Digits 10 Hz 20 Hz 0 0 74 3 Hz 5 Hz 0 0 12 0 12 20 Hz 40 Hz 0 0 22 5 Hz 10 Hz 0 0 17 0 17 40 Hz 100 Hz 0 0 06 0 73 10 Hz 40 Hz 0 0 2 0 2 100 Hz 200 Hz 0 0 01 0 22 40 Hz 100 Hz 0 0 06 0 21 200 Hz 1 kHz 0 0 0 18 100 Hz 300 Hz 0 0 03 0 21 gt 1 kHz 0 0 0 300 Hz 1 kHz 0 0 01 0 07 gt 1 kHz 0 0 0 02 1 Specifications are for 1 hour warm up and 61 digits Slow ac filter 2 Relative to calibration standards 3 20 over range on all ranges except 300 Vac and 1 Aac ranges 4 For sinewave input gt 5 of range For inputs from 1 to 5 of range and lt 50 kHz add 0 1 of range additional error 5 Typically 30 of reading error at 1 MHz limited to 1x108 V Hz 6 Input gt 100 mV For 10 mV inputs multiply of reading error x 10 7 Specified only for inputs gt 10 mA 406 Chapter 9 Specifications AC Measurement and Operating Characteristics E AC Measurement and Operating Characteristics AC Measurement Characteristics l AC Operating Characteristics True RMS AC Voltage Measurement Method AC coupled True RMS measures the ac component of
58. 21 thermistor 21 thermocouples 21 connector pinout alarm output 128 RS 232 273 connector location Alarm output 5 128 Channel Advance 5 Channel Closed 5 Ext Trig 5 83 HP IB 5 RS 232 5 contact debounce totalizer 396 protection 385 resistance 399 continuous scan count 86 conversion accuracy RTD 345 thermistor 345 thermocouple 345 copying channel configuration 25 correlated noise 341 365 count scan continuous 38 86 default value 38 86 settings 38 86 count calibration 159 clearing relay cycles 148 reading relay cycles 147 399 count down time 81 counter adding to scan list 44 manually reset 44 reading count 44 reset mode 44 crest factor defined 362 errors 407 crosspoint switching 59 crosstalk 411 CURR AC BANDwidth command 224 current limitation DAC 139 397 current measurements ac low frequency filter 116 361 ac settling time 116 361 burden voltage 368 connections 21 low frequency filter 116 361 measurement ranges 21 116 valid channels 116 custom label Mx B displaying character 120 valid characters 120 cycles clearing relay count 148 reading relay count 147 399 D DAC output HP 34907A current limitations 139 397 differential errors 398 integral errors 398 simplified schematic 397 writing to 45 data acquisition overview 50 data bits RS 232 factory setting 152 selecting 152 data frame format RS 232 272 DATA
59. 8 Tutorial System Cabling and Connections Sources of System Cabling Errors Radio Frequency Interference Most voltage measuring instruments can generate false readings in the presence of large high frequency signals Possible sources of high frequency signals include nearby radio and television transmitters computer monitors and cellular telephones High frequency energy can also be coupled to the internal DMM on the system cabling To reduce the interference try to minimize the exposure of the system cabling to high frequency RF sources If your application is extremely sensitive to RFI radiated from the instrument use a common mode choke in the system cabling as shown below to attenuate instrument emissions Torroid To Plug In To Transducers Module 4 339 Chapter 8 Tutorial System Cabling and Connections Thermal EMF Errors Thermoelectric voltages are the most common source of error in low level dc voltage measurements Thermoelectric voltages are generated when you make circuit connections using dissimilar metals at different temperatures Each metal to metal junction forms a thermocouple which generates a voltage proportional to the junction temperature difference You should take the necessary precautions to minimize thermocouple voltages and temperature variations in low level voltage measurements The best connections are formed using copper to copper crimped connections The table below shows common thermoele
60. AC RANGe lt range gt MIN MAX lt ch_list gt FREQuency VOLTage RANGe lt range gt MIN MAX lt ch_list gt PERiod VOLTage RANGe lt range gt MIN MAX lt ch_list gt Select the measurement range for the function selected on the specified channels MIN selects the lowest range MAX selects the highest range SENSe VOLTage DC RANGe lt ch_list gt MIN MAX VOLTage AC RANGe lt ch_list gt MIN MAX RESistance RANGe lt ch_list gt MIN MAX FRESistance RANGe lt ch_list gt MIN MAX CURRent DC RANGe lt ch_list gt MIN MAX CURRent AC RANGe lt ch_list gt MIN MAX FREQuency VOLTage RANGe lt ch_list gt MIN MAX PERiod VOLTage RANGe lt ch_list gt MIN MAX Query the measurement range on the specified channels Returns a number in the form 1 00000000E 01 SENSe VOLTage DC RANGe AUTO OFF ON lt ch_list gt VOLTage AC RANGe AUTO OFF ON lt ch_list gt RESistance RANGe AUTO OFF ON lt ch_list gt FRESistance RANGe AUTO OFF ON lt ch_list gt CURRent DC RANGe AUTO OFF ON lt ch_list gt CURRent AC RANGe AUTO OFF ON lt ch_list gt FREQuency VOLTage RANGe AUTO OFF ON lt ch_list gt PERiod VOLTage RANGe AUTO OFF ON lt ch_list gt Disable or enable autoranging on the specified channels Autoranging thresholds Down
61. Any channel that can be read by the instrument can be monitored This includes any combination of temperature voltage resistance current frequency or period measurements on multiplexer channels You can also monitor a digital input port or the totalizer count on the multifunction module Monitoring is not allowed with the actuator module the matrix module or the RF multiplexer modules e The Monitor function is equivalent to making continuous measurements on a single channel with an infinite scan count Only one channel can be monitored at a time but you can change the channel being monitored at any time e Readings acquired during a Monitor are not stored in memory but they are displayed on the front panel however all readings froma scan in progress at the same time are stored in memory e Mx B scaling and alarm limits are applied to the selected channel during a Monitor and all alarm data is stored in the alarm queue which will be cleared if power fails e A scan in progress always has priority over the Monitor function The instrument will take at least one monitor reading per scan sweep and will take more as time permits e You can monitor a multiplexer channel only if the internal DMM is installed and enabled see Internal DMM Disable on page 145 The channel must also be configured to be part of the scan list e You can monitor a digital input channel or totalizer channel even if the channel is not part of
62. Configuration Alarm Output State Alarm Output Slope Module Hardware HP 34901A 34902A 34908A HP 34903A 34904A HP 34905A 34906A HP 34907A System Related Operations Display State Error Queue Stored States Preset State No Change No Change No Change No Change Count Not Reset When Read No Change Preset State No Change All Readings are Cleared All Statistical Data is Cleared No Change No Change No Change No Change Stopped Preset State No Change No Change No Change Preset State No Change No Change No Change No Change Output Lines are Cleared No Change Preset State Reset All Channels Open Reset All Channels Open Reset Channels s11 and s21 Selected Reset Both DIO Ports Input Count 0 Both DACs 0 Vdc Preset State On Errors Not Cleared No Change ESet command from the remote interface 161 Chapter 4 Features and Functions Multiplexer Module Default Settings Multiplexer Module Default Settings The table below shows the default settings for each measurement function on the multiplexer modules When you configure a channel for a particular function these are the default settings Temperature Measurements Temperature Units Integration Time Display Resolution Thermocouple Type Open T C Detection Reference Junction Source RTD Type RTD Reference Resistance Thermistor Type Channel Delay Voltage Measurements Range Resolution Integration Time Input Resist
63. D Integration Time Integration time is the period of time that the instrument s analog to digital A D converter samples the input signal for a measurement Integration time affects the measurement resolution for better resolution use a longer integration time and measurement speed for faster measurements use a shorter integration time e Integration time is specified in number of power line cycles PLCs Select from 0 02 0 2 1 2 10 20 100 or 200 power line cycles The default is 1 PLC e Only theintegral number of power line cycles 1 2 10 20 100 or 200 PLCs provide normal mode line frequency noise rejection e You can also specify integration time directly in seconds this is called aperture time Select a value between 400 us and 4 seconds with 10 us resolution e For temperature measurements the integration time is fixed at 1 PLC e The only way to control the reading rate for ac measurements is by changing the channel delay see page 88 or by setting the ac filter to the highest frequency limit see page 114 e The specified integration time is used for all measurements on the selected channel If you have applied Mx B scaling or have assigned alarms to the selected channel those measurements are also made using the specified integration time Measurements taken during the Monitor function also use the specified integration time e The following table shows the relationship between integration ti
64. Does Not Turn On Use the following steps to help solve problems you might encounter when turning on the instrument If you need more help refer to the HP 34970A Service Guide for instructions on returning the instrument to Hewlett Packard for service Verify that there is ac power to the instrument First verify that the power cord is firmly plugged into the power receptacle on the rear panel of the instrument You should also make sure that the power source you plugged the instrument into is energized Then verify that the instrument is turned on The On Standby switch is located on the lower left side of the front panel Verify the power line voltage setting The line voltage is set to the proper value for your country when the instrument is shipped from the factory Change the voltage setting if it is not correct The settings are 100 120 220 or 240 Vac Note For 127 Vac operation use the 120 Vac setting For 230 Vac operation use the 220 Vac setting See the next page if you need to change the line voltage setting Verify that the power line fuse is good The instrument is shipped from the factory with a 500 mA fuse installed This is the correct fuse for all line voltages See the next page if you need to replace the power line fuse To replace the 500 mAT 250 V fuse order HP part number 2110 0458 27 Chapter 1 Quick Start If the Instrument Does Not Turn On 1 Remove the power cord
65. EVENt Ch 01 Ch 02 Ch 03 Ch 04 Ch 05 DIO LSB DIO MSB Totalizer DAC DAC CALCulate COMPare TYPE EQUal NEQual lt ch_list gt COMPare TYPE lt ch_list gt COMPare DATA lt data gt lt ch_list gt COMPare DATA lt ch_list gt COMPare MASK lt mask gt lt ch_list gt COMPare MASK lt ch_list gt COMPare STATe OFF ON lt ch_list gt COMPare STATe lt ch_list gt This command applies to all channels in the instrument Global setting Default parameters are shown in bold 193 Chapter 5 Remote Interface Reference SCPI Command Summary Digital Input Commands see page 255 for more information Ch 01 Ch 02 Cho3 Cho4 Chos DIO LSB DIO MSB Totalizer DAC DAC CONFigure DIGital BYTE lt scan_list gt CONFigure lt ch_list gt SENSe DIGital DATA BYTE WORD lt ch_list gt Totalizer Commands see page 256 for more information Ch 01 Ch 02 Ch 03 DIO LSB DIO MSB Totalizer DAC DAC Ch 04 Ch 05 CONFigure TOTalize READ RRESet lt scan_list gt CONFigure lt ch_list gt SENSe OTalize TYPE READ RRESet lt ch_list gt OTalize TYPE lt ch_list gt SENSe OTalize SLOPe NEGative POSitive lt ch_list gt OTalize SLOPe lt c
66. Excel 7 0 Example ScanChannels Macro r r r r r r r r r r O S This Excel Macro Visual Basic configures the HP 34970A for scanning with the HP 34901A HP 34902A or HP 34908A multiplexer modules When this subroutine is executed it will scan 5 channels and display the readings on a spreadsheet You can easily modify the channels in the scan list number of scans channel delay and scan delay To make these changes modify the code in the section titled SET UP Note that you must have one of the above modules installed in slot 100 for this program to run properly You must also have an HP IB interface card installed in your PC with the VISA or VTL library ption Explicit ub ScanChannels Dim columnIndex As Integer The column number of the data 1 indicates the first data column Total number of scans Total number of scanned channels Time interval in seconds between scans Reading count in instrument memory Store the string returned from instrument List of channels included in scan Delay between relay closure and measurement Dim numberScans As Integer Dim numberChannels As Integer Dim ScanInterval As Single Dim points As Integer Dim replyString As String Dim scanList As String Dim channelDelay As Single Dim Channel As Integer Range al ba40 ClearContents Clear the spreadsheet sy NSS NSS OTT Ur OY WY re Pre OY WY We Oye OY Wy We Pe Oye Oy We OY Oe OY vy ne PY Oe OY OY Oe Pe oe OY OY Oe OY
67. H c ct ct NSe RRen URRen ESEIA C ct ct gure CONFigure ENSe CURRent CURRent CURRent CURRent ENSe CURRent CURRent DC DC DC DC DC DE DC DG DC DC T CURRent AC lt resolution gt MIN MAX DEF lt scan_list gt lt ch_list gt AC AC AC AC AC AC lt ch_list gt RANGe lt range gt MIN MAX lt ch_list gt RANGe lt ch_list gt MIN MAX RANGe AUTO OFF ON lt ch_list gt RANGe AUTO lt ch_list gt RESolution lt resolution gt MIN MAX lt ch_list gt RESolution lt ch_list gt MIN MAX APERture lt time gt MIN MAX lt ch_list gt APERture lt ch_list gt MIN MAX NPLC 0 02 0 2 1 2 10 20 100 200 MIN MAX lt ch_list gt NPLC lt ch_list gt MIN MAX lt range gt AUTO MIN MAX DEF RANGe lt range gt MIN MAX lt ch_list gt RANGe lt ch_list gt MIN MAX RANGe AUTO OFF ON lt ch_list gt RANGe AUTO lt ch_list gt BANDwidth 3 20 200 MIN MAX lt ch_list gt BANDwidth lt ch_list gt MIN MAX B This command redefines the scan list when executed Default parameters are shown in bold 190 Chapter 5 Remote Interface Reference SCPI Command Summary Frequency and Period Configuration
68. LAST command 92 234 DATA POINts command 92 235 DATA POINts EVENt THR command 391 DATA REMove command 235 DATA REMove command 92 date calendar factory setting 145 setting 22 145 de current connections 21 measurement ranges 21 dc voltage bias current 358 common mode noise 354 connections 21 injected current 356 input resistance 113 357 loading errors 357 measurement ranges 21 113 signal conditioning 354 423 Index decimal format digital input 42 133 declaration of conformity inside rear cover default delays channel delays 89 delay channel delay 88 device clear 302 DIAG DMM CYCL CLEar command 294 DIAG DMM CYCL command 294 DIAG PEEK SLOT DATA command 265 DIAG POKE SLOT DATA command 265 DIAG RELay CYCL CLEar command 294 DIAG RELay CYCL command 294 dielectric withstand voltage 335 differential error DAC 398 diffusion error 352 digital channels external scanning 97 digital input HP 34907A 8 bit vs 16 bit operations 133 adding to scan list 42 133 binary format 42 133 block diagram 174 card reset 133 134 decimal format 42 133 scanning 76 simplified schematic 392 using alarms 130 digital output HP 34907A 8 bit vs 16 bit operations 138 binary format 43 138 card reset 138 decimal format 43 138 driving microwave switches 394 simplified schematic 393 sink current 393 TTL drive capability 393 DIG DATA BYTE
69. Memory Battery Backed 4 year typical life P Readings 50 000 readings States 5 instrument states Alarm Queue Up to 20 events Function Resolution Readings s DCV 2 Wire Ohms 61 2 10 PLC 6 5 51 1 PLC 57 47 41 0 02 PLC 600 Thermocouple 0 1 C 1 PLC 57 47 0 02 PLC 220 RTD Thermistor 0 01 C 10 PLC 6 5 0 1 C 1 PLC 57 47 1 C 0 02 PLC 220 ACV 61 Slow 3 Hz 0 14 61 2 Medium 20 Hz 1 61 2 Fast 200 Hz 8 61 S 100 Frequency Period 61 Digits 1s gate 1 51 Digits 100 ms 9 4 Digits 10 ms 70 System Speeds 4 INTO Memory Ch s Single Channel DCV 600 34902A Scanning DCV 250 34907A Scanning Digital Input 250 34902A Scanning DCV scaling and 1 alarm fail 220 34907A Scanning Totalize 170 34902A Scanning Temperature 160 34902A Scanning ACV 3 100 34902A Scanning DCV Ohms alternate channels 90 34901A 34908A Scanning DCV 60 INTO and OUT of Memory to HP IB or RS 232 INIT FETCh 34902A Scanning DCV 180 34902A Scanning DCV with Time stamp 150 OUT of Memory to HP IB Readings 800 Readings with Time stamp 450 Readings with all Format Options ON 310 OUT of Memory to RS 232 Readings 600 Readings with Time stamp 320 Readings with all Format Options ON 230 DIRECT to HP IB or RS 232 Single Channel DCV 440 34902A Scanning DCV 200 Single Channel MEAS DCV 10 or MEAS DCV 1 25 Single Channel MEAS DCV or MEAS OHMS 12 General Specifications Power Supply Power Line Fr
70. Modules at a Glance For complete specifications on each plug in module refer to the module sections in chapter 9 HP 34901A 20 Channel Armature Multiplexer e 20 channels of 300 V switching e Two channels for DC or AC current measurements 100 nA to 1A e Built in thermocouple reference junction e Switching speed of up to 60 channels per second e Connects to the internal multimeter e For detailed information and a module diagram see page 164 Each of the 20 channels switches both HI and LO inputs thus providing fully isolated inputs to the internal multimeter The module is divided into two banks of 10 two wire channels each When making four wire resistance measurements channels from Bank A are automatically paired with channels from Bank B Two additional fused channels are included on the module 22 channels total for making calibrated DC or AC current measurements with the internal multimeter external shunt resistors are not required You can close multiple channels on this module only if you have not configured any channels to be part of the scan list Otherwise all channels on the module are break before make HP 34902A 16 Channel Reed Multiplexer e 16 channels of 300 V switching e Built in thermocouple reference junction e Switching speed of up to 250 channels per second e Connects to the internal multimeter e For detailed information and a module diagram see page 166 Use this module for high speed scanning and hi
71. OFF and ONCE parameters havea similar effect Autozero OF F does not issue a new zero measurement Autozero ONCE issues an immediate zero measurement ZERO AUTO OFF ONCE ON lt ch_list gt 105 Chapter 4 Features and Functions Temperature Measurement Configuration Temperature Measurement Configuration This section contains information to help you configure the instrument for making temperature measurements F or more information on the types of temperature transducers see Temperature Measurements starting on page 345 in chapter 8 The instrument supports direct measurement of thermocouples RTDs and thermistors The instrument supports the following specific types of transducers in each category Thermocouples RTDs Thermistors Supported Supported Supported B E J K N R S T Ro 492 to 2 1 ka 2 2 KQ 5 KQ 10 kQ a 0 00385 DIN IEC 751 44000 Series a 0 00391 Measurement Units e Theinstrument can report temperature measurements in C Celsius F Fahrenheit or K Kelvins You can mix temperature units on different channels within the instrument and on the same module e Theinstrument selects Celsius when the probe type is changed and after a Factory Reset RST command An Instrument Preset SYSTem PRESet command or Card Reset SySTem CPON command does not change the units setting e Setting the Mx B measurement label to C F or K has no effect
72. OY TY PT YP YOY TOYO We Pee OY OY We PY Oe OY OY WYP Oe OY OY Oe OY oe OY OY Oe 0 Oe OY OY Oe OY We OY OY Oe 0 Oe YO nev Oe OY ne neva To change the HP IB address modify the variable VISAaddr below VISAaddr 9 OpenPort Open communications on HP IB SendSCPI RST Issue a Factory Reset to the instrument VTP Oe Ue re Pre OY vn WY We Pee OY nny We Pe OY YOY WYO oe OY vy WYO Oe OY OY We OY Oe OY OY Oe OO OY OY Oe vO OY OY nev vey ne eae vn ne SET UP Modify this section to select the number of readings channel delay and channel number to be measured numberMeasurements 10 Number of readings measurementDelay 0 1 Delay in secs between relay closure and measurement Configure the function range and channel see page 201 for more information SendSCPI CONF VOLT DC 103 Configure channel 103 for dc voltage VET Pr YT Ue re Pe re OY WY We Pee OY YOY WYP Oe OY Oy We PY We OY OY Oe OY Oe OY OY Oe OY Oe OY OO OO OY OOOO OOo no neve na Select channel delay and number of readings SendSCPI ROUT CHAN DELAY amp Str measurementDelay SendSCPI TRIG COUNT amp Str numberMeasurements Set up the spreadsheet headings Cells 2 1 Chan Delay Cells 2 2 measurementDelay Cells 2 3 sec Cells 3 1 Reading Cells 3 2 Value SendSCPI INIT Start the readings and wait for instrument to put Do one reading in memory SendSCPI DATA POINTS Get the nu
73. Or INITiate command The MEASure and READ commands send readings directly to the instrument s output buffer but readings are not stored in memory The INITiate command stores readings in memory Use the FETCh command to retrieve stored readings from memory See the examples starting on page 201 in chapter 5 for more information on using these commands e When you reconfigure a channel and add it to the scan list using MEASure Or CONFigure it is important to note that the previous configuration on that channel is lost For example assume that a channel is configured for dc voltage measurements When you reconfigure that channel for thermocouple measurements the previous range resolution and channel delay are set to their Factory Reset RST command state e Each time you initiate a new scan the instrument clears all previously stored readings e Tostop a scan execute the ABORt Command 79 Chapter 4 Features and Functions Scanning Scan Interval You can configure the event or action that controls the onset of each sweep through the scan list a sweep is one pass through the scan list e You can set the instrument s internal timer to automatically scan at a specific interval You can also program a time delay between channels in the scan list e You can manually control a scan by repeatedly pressing from the front panel e You can start a scan by sending a software command from the r
74. Output a DC Voltage on page 45 e To Configure the Remote Interface on page 46 e To Store the Instrument State on page 48 34 Chapter 2 Front Panel Overview Front Panel Menu Reference Front Panel Menu Reference This section gives an overview of the front panel menus The menus are designed to automatically guide you through all parameters required to configure a particular function or operation The remainder of this chapter shows examples of using the front panel menus Configure the measurement parameters on the displayed channel e Select measurement function dc volts ohms etc on the displayed channel e Select transducer type for temperature measurements e Select units C F or K for temperature measurements e Select measurement range or autorange e Select measurement resolution e Copy and paste measurement configuration to other channels Configure the scaling parameters for the displayed channel e Set the gain M and offset B value for the displayed channel e Make a null measurement and store it as the offset value e Specify a custom label RPM PSI etc for the displayed channel Configure alarms on the displayed channel e Select one of four alarms to report alarm conditions on the displayed channel e Configure a high limit low limit or both for the displayed channel e Configure a bit pattern which will generate an alarm digital input only Config
75. Reading memory is not cleared when you read it 2 As alarm events are generated they are also logged in an alarm queue which is separate from reading memory This is the only place where non scanned alarms get logged alarms during a monitor alarms generated by the multifunction module etc Up to 20 alarms can be logged in the alarm queue If more than 20 alarm events are generated they will be lost only the first 20 alarms are saved Even if the alarm queue is full the alarm status is still stored in reading memory during a scan The alarm queue is cleared by the cLs clear status command when power is cycled and by reading all of the entries A Factory Reset RST command does not clear the alarm queue 247 Chapter 5 Remote Interface Reference Alarm System Overview e You can assign an alarm to any configured channel and multiple channels can be assigned to the same alarm number However you cannot assign alarms on a specific channel to more than one alarm number e When an alarm occurs the instrument stores relevant information about the alarm in the queue This includes the reading that caused the alarm the time of day and date of the alarm and the channel number on which the alarm occurred The information stored in the alarm queue is always in absolute time format and is not affected by the FORMat READing TIME TYPE command setting e You must configure the channel function transducer type
76. Recent Reading on Channel 24 Measure Measure i Chapter 1 Quick Start To Copy a Channel Configuration To Copy a Channel Configuration After configuring a channel to be included in the scan list you can copy that same configuration to other channels in the instrument including digital channels on the multifunction module This feature makes it easy to configure several channels for the same measurement When you copy the configuration from one channel to another the following parameters are automatically copied to the new channel e Measurement configuration e Mx B scaling configuration e Alarm configuration e Advanced measurement configuration Select the channel to copy the configuration from Turn the knob until the desired channel is shown on the right side of front panel display For this example let s copy the configuration from channel 103 Select the copy function Use the knob to scroll through the measurement choices until you see COPY CONFIG When you press to make your selection the menu automatically guides you to the next step Select the channel to copy the configuration to Turn the knob until the desired channel is shown on the right side of front panel display For this example let s copy the configuration to channel 105 PASTE TO Copy the channel configuration to the selected channel Note To copy the same configuration to other channels repeat this p
77. SOURce BUS IMMediate EXTernal ALARm1 ALARm2 ALARm3 ALARm4 TIMer SOURcCe TRIGger TIMer lt seconds gt MIN MAX TIMer TRIGger COUNt lt count gt MIN MAX INFinity COUNt TRG INITiate READ State Storage Commands see page 261 for more information SAV 0 1 2 3 4 5 RCL 0 1 2 3 41 5 EMory STATe NAME 1 2 3 4 5 lt name gt NAME 1 2 3 4 5 EMory STATe DELete 0 1 2 3 4 5 EMory STATe RECall AUTO OFF ON RECal1l AUTO EMory STATe VALid 0 1 2 3 4 5 EMory NSTates This command applies to all channels in the instrument Global setting Default parameters are shown in bold 196 Chapter 5 Remote Interface Reference SCPI Command Summary System Related Commands see page 264 for more information SYSTem DATE DATE IME lt hh gt lt mm gt lt ss sss gt IME lt yyyy gt lt mm gt lt dd gt FORMat READing TIME TYPE ABSolute RELative READing TIME TYPE IDN SYSTem CTYPe 100 200 300 DIAGnostic POKE SLOT DATA 100 200 300 lt quoted_string gt PEEK SLOT DATA 100 200 300 DISPlay OFF ON DISPlay DISPlay TEXT lt quoted_string gt EXT EXT CLEar INSTrument DMM OFF ON DMM DMM INSTalled RST SYSTem PRESet SYSTem
78. Set the baud rate and configure the modem to expect more commands amp F1 Place the modem in its factory configuration which is compatible with most IBM compatible PCs S0 1 Set to auto answer after one ring E Disable error codes Q1 Disable result codes amp W Store settings for power on profile Configure the HP 34970A for the Modem flow control mode for more information see Flow Control Selection on page 153 Remove the remote modem from the PC Connect the remote modem to the HP 34970A using the RS 232 cable supplied if you ordered the internal DMM and modem adapter HP part number 5181 6642 The modem adapter is available in the HP 34399A Adapter kit After turning on the remote modem you should notice that the AA auto answer light is on When you turn on the HP 34970A you should notice that the TR instrument ready light is on Connect the remote modem to the phone line From the local modem dial up the remote modem using HP BenchLink Data Logger or another software application 274 Chapter 5 Remote Interface Reference The SCPI Status System The SCPI Status System This section describes the structure of the SCPI status system used by the HP 34970A The status system records various conditions and states of the instrument in five register groups as shown on the following page Each of the register groups is made up of several low level registers
79. Summary Scanning With an External Instrument see page 239 for more information ROUTe SCAN lt scan_list gt SCAN SCAN SIZE TRIGger SOURce BUS IMMediate EXTernal TIMer SOURcCe TRIGger TIMer lt seconds gt MIN MAX TIMer TRIGger COUNt lt count gt MIN MAX INFinity COUNt ROUTe CHANnel1 DI CHANnel D say lt seconds gt lt ch_list gt ay lt ch_list gt EI ROUTe CHANnel ADVance SOURce EXTernal BUS IMMediate CHANnel ADVance SOURce ROUTe CHANnel FWIRe OFF ON lt ch_list gt CHANnel FWIRe lt ch_list gt INSTrument DMM OFF ON DMM DMM INSTalled B This command redefines the scan list when executed This command applies to all channels in the instrument Global setting Default parameters are shown in bold 186 Chapter 5 Remote Interface Reference SCPI Command Summary Temperature Configuration Commands see page 219 for more information CONE igure TEMPerature T PREPIS RTD FRTD THERmistor DEF lt type gt DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt
80. V Vp Noise Correlated noise while rare is especially detrimental Correlated noise will always add directly to the input signal Measuring a low level signal with the same frequency as the local power line is a common situation that is prone to this error You should use caution when switching high level and low level signals on the same module It is possible that high level charged voltages may be discharged onto a low level channel It is recommended that you either use two different modules or separate the high level signals from the low level signals with an unused channel connected to ground 365 Chapter 8 Tutorial Measurement Fundamentals Measurements Below Full Scale You can make the most accurate ac measurements when the internal DMM is at full scale of the selected range Autoranging occurs at 10 and 120 of full scale This enables you to measure some inputs at full scale on one range and 10 of full scale on the next higher range Note that the measurement accuracy will be significantly different for the two cases For highest accuracy you should use manual ranging to select the lowest range possible for the measurement Temperature Coefficient and Overload Errors The internal DMM uses an ac measurement technique that periodically measures and removes internal offset voltages when you select a different function or range When manual ranging to a new range in an overload condition the internal offset measuremen
81. You cannot query the SCPI version from the front panel e The following command returns the SCPI version SYSTem VERSion Returns a string in the form YYYY V where YYYY represents the year of the version and V represents a version number for that year for example 1994 0 149 Chapter 4 Features and Functions Remote Interface Configuration Remote Interface Configuration This section gives information on configuring the instrument for remote interface communication For more information on configuring the instrument from the front panel see To Configure the Remote Interface starting on page 46 For more information on the SCPI commands available to program the instrument over the remote interface see chapter 5 Remote nterface Reference starting on page 179 HP IB Address Each device on the HP IB IEEE 488 interface must have a unique address You can set the instrument s address to any value between 0 and 30 The address is set to 9 when the instrument is shipped from the factory The HP IB address is displayed at power on You can set the HP IB address from the front panel only e The address is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e Your computer s HP IB interface card has its own address Be sure to avoid using the computer s
82. a known dc current to an unknown resistance and measuring the dc voltage drop HI To Amplifier and m O m Analog to Digital T Converter Runknown ltest D l me O LO The internal DMM offers two methods for measuring resistance 2 wire and 4 wire ohms For both methods the test current flows from the input HI terminal through the resistor being measured For 2 wire ohms the voltage drop across the resistor being measured is sensed internal to the DMM Therefore test lead resistance is also measured For 4 wire ohms separate sense connections are required Since no current flows in the sense leads the resistance in these leads does not give a measurement error 4 Wire Ohms Measurements The 4 wire ohms method provides the most accurate way to measure small resistances Test lead multiplexer and contact resistances are automatically reduced using this method The 4 wire ohms method is often used in automated test applications where long cable lengths input connections and a multiplexer exist between the internal DMM and the device under test The recommended connections for 4 wire ohms measurements are shown in the diagram on the following page A constant current source forcing current I through unknown resistance R develops a voltage measured by a dc voltage front end The unknown resistance is then calculated using Ohm s Law 369 Chapter 8 Tutorial Measurement Fundamentals The 4 wire ohms
83. a digital port or a read of the totalizer count on the multifunction module Scanning is allowed with the following modules e HP 34901A 20 Channe Multiplexer e HP 34902A 16 Channel Multiplexer e HP 34907A Multifunction Module digital input and totalizer only e HP 34908A 40 Channe Single Ended Multiplexer Automated scanning is not allowed with the actuator module the matrix module or the RF multiplexer modules In addition a scan cannot include a write to a digital port or a voltage output from a DAC channel However you can write your own program to manually create a scan to include these operations Rules for Scanning e Before you can initiate a scan you must set up a scan list to include all desired multiplexer or digital channels Channels which are not in the scan list are skipped during the scan The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300 Measurements are taken only during a scan and only on those channels which are included in the scan list The Sample annunciator turns on during each measurement e You can store up to 50 000 readings in non volatile memory during a scan Readings are stored only during a scan and all readings are automatically time stamped If memory overflows the MEM annundator will turn on a status register bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved
84. absolute time time of day with date or relative time time since start of scan The TIME query reads whether or not the time is included Returns 0 OFF or 1 ON FORMat READing UNIT OFF ON READing UNIT Disable default or enable the inclusion of measurement units with data produced by READ FETCh or other queries of scan results This command operates in conjunction with the other FORMat READing commands they are not mutually exclusive The UNIT query reads whether or not the units are included Returns 0 OFF or 1 ON FORMat READing TIME TYPE ABSolute RELative READing TIME TYPE Select the time format for storing scanned data in memory You can select absolute time time of day with date or relative time time since start of scan The default is relative time This command operates in conjunction with the FORMat READing TIME command they are not mutually exclusive The TYPE query returns ABS or REL Note The absolute format is considerably slower than the relative format 232 Chapter 5 Remote Interface Reference Scanning Overview Scan Statistics Commands While a scan is running the instrument automatically stores the minimum and maximum readings and calculates the average for each channel You can read these values at any time even during a scan The instrument clears the values when a
85. all channels from the scan list send ROUT SCAN The SCAN query returns a list of channel numbers in the SCPI definite length block format The response begins with the character followed by a single character representing the number of succeeding characters to interpret as a length specifier followed by a length specifier representing the number of bytes in the block followed by a block of that many bytes An empty scan list one with no channels selected will be 13 For example if you send ROUT SCAN 101 103 the ROUT SCAN command will return the following 214 101 102 103 ROUTe SCAN SIZE Query the number of channels in the scan list Returns a value between 0 and 120 channels TRIGger SOURce BUS IMMediate EXTernal ALARm 1 2 3 4 TIMer SOURce Select the trigger source to control the onset of each sweep through the scan list a sweep is one pass through the scan list The selected source is used for all channels in the scan list The instrument will accept a software bus command an immediate continuous scan trigger an external TTL trigger pulse an alarm initiated action or an internally paced timer The default is M Mediate The SOUR query returns the present scan trigger source Returns BUS IMM EXT ALAR1 ALAR2 ALAR3 ALAR4 or TIM 228 Chapter 5 Remote Interface Reference Scanning Overview TRIG
86. an HP IB IEEE 488 interface and an RS 232 interface Only one interface can be enabled at a time The HP IB interface is selected when the instrument is shipped from the factory HP IB Configuration Select the HP IB interface HPIG 488 Select the HP IB address You can set the instrument s address to any value between 0 and 30 The factory setting is address 9 ADDRESS 09 Save the change and exit the menu Note Your computer s HP IB interface card has its own address Be sure to avoid using the computer s address for any instrument on the interface bus Hewlett Packard HP IB interface cards generally use address 21 Chapter 2 Front Panel Overview To Configure the Remote Interface RS 232 Configuration 1 Select the RS 232 interface Interface R5 232 2 Select the baud rate eas Select one of the following 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud 9208 BAUD 3 Select the parity and number of data bits Interface Select one of the following None 8 data bits factory setting Even 7 data bits or Odd 7 data bits When you set the parity you are also indirectly setting the number of data bits EVEN 7 BITS 4 Select the flow control method ees Select one of the following None no flow control RTS CTS DTR DSR XON XOFF factory setting or Modem FLOW OTR GSR 5 Save the changes and exit the menu In
87. an open connection is detected greater than 5 kQ on the 10 kQ range the instrument reports an overload condition for that channel The default is OFF The CHEC query returns the thermocouple check setting Returns 0 OFF or 1 ON SENSe TEMPerature TRANsducer TCouple RJUNction lt temperature gt MIN MAX lt ch_list gt RJUNction lt ch_list gt Set the fixed reference junction temperature for thermocouple measurements on the specified channels Specify a temperature between 20 C and 80 C always specify the temperature in C regardless of the temperature units selected The default is 0 C The RJUN query returns the fixed junction temperature in C currently selected MIN selects 20 C MAX selects 80 C SENSe TEMPerature RJUNction lt ch _list gt Query the internal reference junction temperature on the specified channels useful only for an internal reference source Returns the reference temperature in C regardless of the temperature units currently selected Returns a number in the form 2 89753100E 01 221 Chapter 5 Remote Interface Reference Temperature Configuration Commands RTD Commands SENSe TEMPerature TRANsducer RTD TYPE 85 91 lt ch_list gt RTID TYPE lt ch_list gt FRTD TYPE 85 91 lt ch_list gt FRTD TYPE lt ch_list gt Select the RTD type for 2 wire or 4 wire meas
88. and range you select as well as the input signal level The reading error varies according to the input level on the selected range This error is expressed in percent of reading The following table shows the reading error applied to the internal DMM s 24 hour dc voltage specification Reading Error Reading Range Input Level of reading Error Voltage 10 Vdc 10 Vdc 0 0015 lt 150 uV 10 Vdc 1 Vdc 0 0015 lt 15 uV 10 Vdc 0 1 Vdc 0 0015 lt 1 5 uV 414 Chapter 9 Specifications To Calculate Total Measurement Error Understanding the of range Error The range error compensates for inaccuracies that result from the function and range you select The range error contributes a constant error expressed as a percent of range independent of the input signal level The following table shows the range error applied to the DMM s 24 hour dc voltage specification Range Error Range Range Input Level of range Error Voltage 10 Vdc 10 Vdc 0 0004 lt 40 uV 10 Vdc 1 Vde 0 0004 lt 40 uV 10 Vdc 0 1 Vdc 0 0004 lt 40 uV Total Measurement Error To compute the total measurement error add the reading error and range error You can then convert the total measurement error to a percent of input error or a ppm part per million of input error as shown below Total Measurement Error Input Signal Level of input error x 100 Total Measurement Error t x 1 0
89. any of the four available alarms numbered 1 through 4 Configure the channel You must configure the channel function transducer type etc before setting any alarm limits If you change the measurement configuration alarms are turned off and the limit values are cleared If you plan to use Mx B scaling on a channel which will also use alarms be sure to configure the scaling values first Select which of the four alarms you want to use USE ALARN I Select the alarm mode on the selected channel You can configure the instrument to generate an alarm when a measurement exceeds the specified HI or LO limits or both on a measurement channel HI ALARM ONLY Alarm Chapter 2 Front Panel Overview To Configure Alarm Limits Set the limit value The alarm limit values are stored in non volatile memory for the specified channels The default values for the high and low limits are 0 The low limit must always be less than or equal to the high limit even if you are using only one of the limits A Factory Reset clears all alarm limits and turns off all alarms An Instrument Preset or Card Reset does not clear the alarm limits and does not turn off alarms 40 250 G00 C Run the scan and store the readings in memory If an alarm occurs on a channel as it is being scanned then that channel s alarm status is stored in reading memory as the readings are taken Each time you start a new scan the instrument clears all
90. between modules of the same type from within your program The custom label is stored in non volatile memory on the module Note that the instrument must be unsecured see the calibration section on page 292 before you can store the custom label The following program statement shows how to add a custom label to the module installed in slot 100 DIAG POKE SLOT DATA 100 Module_A 265 Chapter 5 Remote Interface Reference System Related Commands DISPlay OFF ON DISPlay Disable or enable the front panel display When disabled the entire front panel display goes dark and all display annunciators except ERROR are disabled All keys except are locked out when the display is disabled The display is automatically enabled when power is cycled after a Factory Reset RST command or when you return to local by pressing C The DISP query the front panel display setting Returns 0 OFF or 1 ON DISPlay TEXT lt quoted_string gt TEXT Display a message on the instrument s front pane display The instrument can display up to 13 characters on the front panel if you attempt to send more than 13 characters an error is generated The TEXT query reads the message sent to the instrument front panel and returns a quoted string You can use letters A Z numbers 0 9 and special characters like etc Use the character to display a degree symbol Commas periods
91. called Condition registers Event registers and Enable registers which control the action of specific bits within the register group What is a Condition Register A condition register continuously monitors the state of the instrument The bits in the condition register are updated in real time and the bits are not latched or buffered This is a read only register and bits are not cleared when you read the register A query of a condition register returns a decimal value which corresponds to the binary weighted sum of all bits set in that register What is an Event Register An event register latches the various events from the condition register There is no buffering in this register while an event bit is set subsequent events corresponding to that bit are ignored This is a read only register Once a bit is set it remains set until cleared by a query command such as STATus OPER EVENt Or a CLS dear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in that register What is an Enable Register An enable register defines which bits in the event register will be reported to the Status Byte register group You can write to or read from an enable register A CLS clear status will not clear the enable register but it does clear all bits in the event register A STATus PRESet Clears all bits in the enable register To enable bits in
92. changes in the wire alloy introduce small voltage changes in the measurement Diffusion is caused by exposure to high temperatures along the wire or by physical stress to the wire such as stretching or vibration Temperature errors due to diffusion are hard to detect since the thermocouple will still respond to temperature changes and give nearly correct results The diffusion effects are usually detected as a drift in the temperature measurements Replacing a thermocouple which exhibits a diffusion error may not correct the problem The extension wire and connections are all subject to diffusion Examine the entire measurement path for signs of temperature extremes or physical stress If possible keep the temperature gradient across the extension wire to a minimum 352 Chapter 8 Tutorial Measurement Fundamentals Shunt Impedance The insulation used for thermocouple wire and extension wire can be degraded by high temperatures or corrosive atmospheres These breakdowns appear as a resistance in parallel with the thermocouple junction This is especially apparent in systems using a small gauge wire where the series resistance of the wire is high Shielding Shielding reduces the effect of common mode noise on a thermocouple measurement Common mode noise is generated by sources such as power lines and electrical motors The noise is coupled to the unshielded thermocouple wires through distributed capacitance As the induced current flows
93. channel Returns I if the channel is open or 0 if the channel is closed 259 Chapter 5 Remote Interface Reference Switch Control Commands ROUTe CHANnel FWIRe OFF ON lt ch_list gt CHANnel FWIRe lt ch_list gt This command is valid only when the internal DMM is disabled or removed from the HP 34970A Configure the list of channels for 4 wire external scanning without the internal DMM When enabled the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections For example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel Note that the ROUT CLOSe ROUT CLOSe EXCL and ROUT OPEN commands ignore the current ROUT CHAN FWIRe Setting if no channels arein the scan list The FWIR query returns a 0 4 wire pairing disabled or 1 4 wire pairing enabled for each channel in the scan list ROUTe DONE Query the status of all relay operations Returns a 1 when all relay operations are finished even during a scan SYSTem CPON 100 200 300 ALL Reset the module in the specified slot to its power on state CPON means card power on To reset all three slots specify ALL This is equivalent to pressing from the front panel
94. channel even during a scan This feature is useful for trouble shooting your system before a test or for watching an important signal Any channel that can be read by the instrument can be monitored This includes any combination of temperature voltage resistance current frequency or period measurements on multiplexer channels You can also monitor a digital input port or the totalizer count on the multifunction module Monitoring is not allowed with the actuator module the matrix module or the RF multiplexer modules e The Monitor function is equivalent to making continuous measurements on a single channel with an infinite scan count Only one channel can be monitored at a time but you can change the channel being monitored at any time e Readings acquired during a Monitor are not stored in memory but they are displayed on the front panel however all readings froma scan in progress at the same time are stored in memory e A scan in progress always has priority over the Monitor function The instrument will take at least one monitor reading per scan sweep and will take more as time permits e You can monitor a multiplexer channel only if the internal DMM is installed and enabled see Internal DMM Disable on page 145 The channel must also be configured to be part of the scan list e You can monitor a digital input channel or totalizer channel even if the channel is not part of the scan list the internal DMM is not
95. command 255 DIG DATA WORD command 255 digits number of 100 vs integration time 103 203 dimensions HP 34970A 413 plug in modules 413 DIN IEC 751 106 disabling internal DMM 96 discrete parameters 300 DISPlay command 266 display annunciators 4 enable disable 144 text message 144 DISPlay TEXT command 266 DISPlay TEXT CLEar command 266 dissimilar metals 340 DMM internal block diagram 343 field installation kit See Option 001 Installation Note enabling disabling 145 reading relay count 147 DTR DSR flow mode RS 232 153 E echo commands modem 274 enable register status 275 ERROR annunciator 4 142 304 error messages 303 318 errors ac loading 364 cabling 339 capacitive coupling 381 clearing 142 common mode noise 353 crest factors 407 diffusion error 352 frequency measurements 377 loading de voltage 357 loading input bias current 358 low level ac 341 magnetic fields 340 measurement error 414 multiplexing and switching 381 period measurements 377 reading error queue 142 304 RF multiplexing 391 thermal EMF 340 thermocouple calculation 353 thermocouple reference junction 352 totalizer 396 event register status 275 example programs C and C 328 Excel 7 0 321 Excel macro example programs 321 Express Exchange program 10 EXT annunciator 4 Ext Trig connector 5 83 95 external DMM connections 95 scanning with 95 external reference T C 10
96. control the flow If the instrument is addressed to send data it continues sending data until the XOF F character 13H is received When the XON character 11H is received the instrument resumes sending data e DTR DSR In this mode the instrument monitors the state of the DSR data set ready line on the RS 232 connector When the line goes true the instrument sends data over the interface When the line goes false the instrument stops sending information typically within six characters The instrument sets the DTR line false when the input buffer is almost full approximately 100 characters and releases the line when space is available again e RTS CTS This mode operates the same as the DTR DSR mode but uses the RTS request to send and CTS clear to send lines on the RS 232 connector instead When the CTS line goes true the instrument sends data over the interface When the line goes false the instrument stops sending information typically within six characters The instrument sets the RTS line false when the input buffer is almost full approximately 100 characters and releases the line when space is available again e Modem This mode uses the DTR DSR and RTS CTS lines to control the flow of data between the instrument and a modem When the RS 232 interface is selected the instrument sets the DTR line true The DSR line is set true when the modem is on line The instrument sets the RTS line true when it is rea
97. e g CLEAR 709 2 Clear the event registers using the CLS command 3 Enable the Operation Complete bit bit 0 in the Standard Event register using the ESE 1 command 4 Send the opc command and enter the result to ensure synchronization 5 Execute your command string to program the desired configuration and then send the opc command as the last command note that if a scan is in progress the oPc command will wait until the entire scan is complete When the command sequence is completed the Operation Complete bit bit 0 is set in the Standard Event register 6 Usea Serial Poll to check to see when bit 5 routed from the Standard Event register is set in the Status Byte condition register Y ou could also configure the instrument for an SRQ interrupt by sending SRE 32 Status Byte enable register bit 5 279 Chapter 5 Remote Interface Reference The SCPI Status System The Questionable Data Register The Questionable Data register group provides information about the quality of the instrument s measurement results Any or all of these conditions can be reported to the Questionable Data summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the STATus QU ES ENABle command instrument s error queue A measurement overload condition is always reported in both the Questionable Data
98. event register bits 0 1 2 9 or 10 and the Standard event register bit 3 However no error message is recorded in the Bit Definitions Questionable Data Register Decimal Bit Number Value Definition 0 Voltage Overload 1 Range overload on dc or ac volts 1 Current Overload 2 Range overload on dc or ac current 2 Not Used 4 Returns 0 3 Not Used 8 Returns 0 4 Not Used 16 Returns 0 5 Not Used 32 Returns 0 6 Not Used 64 Returns 0 7 Not Used 128 Returns 0 8 Not Used 256 Returns 0 9 Resistance Overload 512 Range overload on 2 or 4 wire resistance 10 Temperature Overload 1024 Range overload on temperature 11 Totalizer Overflow 2048 Count overflow on a totalizer channel 12 Memory Overflow 4096 Memory is full 1 or more readings are lost 13 Not Used 8192 Returns 0 14 Not Used 16384 Returns 0 15 Not Used 32768 Returns 0 280 Chapter 5 Remote Interface Reference The SCPI Status System The Questionable Data event register is cleared when e You executea cLs clear status command e You query the event register using the STATus QUES EVENt command The Questionable Data enable register is cleared when e You turn on the power PSc does not apply e You execute the STATus PRESet command e You execute the STATus QUES ENABle 0 command 281 Chapter 5 Remote Interface Referenc
99. following sections in this chapter describe each type of multiplexer The following low level multiplexer modules are available with the HP 34970A e HP 34901A 20 Channel Armature Multiplexer e HP 34902A 16 Channel Reed Multiplexer e HP 34908A 40 Channel Single Ended Multiplexer An important feature of a multiplexer used as a DMM input channel is that only one channel is connected at a time For example using a multiplexer module and the internal DMM you could configure a voltage measurement on channel 1 and a temperature measurement on channel 2 The instrument first closes the channel 1 relay makes the voltage measurement and then opens the relay before moving on to channel 2 called break before make switching Other low level switching modules available with the HP 34970A include the following e HP 34903A 20 Channel Actuator e HP 34904A 4x8 Two Wire Matrix 378 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching One Wire Single Ended Multiplexers On the HP 34908A multiplexer all of the 40 channels switch the HI input only with a common LO for the module The module also provides a thermocouple reference junction for making thermocouple measurements for more information on the purpose of an isothermal block see page 350 H ZH ToDMM a Channel 1 LG p O 5 C amp G H AL Channel 2 aoe H Channel 3 AL V AL Channel 4 Note Only one channel can be closed at a tim
100. from the first prior to scaling the result thus giving a more accurate resistance measurement Refer to Offset Compensation on page 115 for more information Offset compensation can be used for 2 wire or 4 wire ohms measurements but not for RTD or thermistor measurements The HP 34970A disables offset compensation when the measurement function is changed or after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SYSTem CPON command does not change the setting If the resistor being measured does not respond quickly to changes in current offset compensation will not produce an accurate measurement Resistors with very large inductances or resistors with large parallel capacitance would fall into this category In these cases the channel delay parameter can be increased to allow more settling time after the current source is switched on or off or offset compensation can be turned off For more information on channel delay see page 88 371 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in Resistance Measurements External Voltages Any voltages present in the system cabling or connections will affect a resistance measurement The effects of some of these voltages can be overcome by using offset compensation as described on the previous page Settling Time Effects The internal DMM has the ability to insert automatic measurement settling delays These delays ar
101. internal DMM s measurement uncertainty can be determined relative to the calibration reference used Absolute accuracy includes the internal DMM s relative accuracy specification plus the known error of the calibration reference relative to national standards such as the U S National Institute of Standards and Technology To be meaningful the accuracy specifications must be accompanied with the conditions under which they are valid These conditions should include temperature humidity and time There is no standard convention among instrument manufacturers for the confidence limits at which specifications are set The table below shows the probability of non conformance for each specification with the given assumptions Specification Probability Criteria of Failure Mean 2 sigma 4 5 Mean 3 sigma 0 3 Variations in performance from reading to reading and instrument to instrument decrease for increasing number of sigma for a given specification This means that you can achieve greater actual measurement precision for a specific accuracy specification number The HP 34970A is designed and tested to meet performance better than mean 3 sigma of the published accuracy specifications 417 Chapter 9 Specifications Interpreting Internal DMM Specifications 24 Hour Accuracy The 24 hour accuracy specification indicates the internal DMM s relative accuracy over its full measurement range for short time interv
102. is restored e If theinstrument is in the middle of a scan sweep when power fails all readings from that partially completed sweep will be discarded Sweep 1 a sweep is one pass through the scan list For example assume that Sweep 2 ih your scan list includes four multiplexer channels and you want to Sweep 3 sweep through the scan list three times see diagram A power failure occurs after the second reading in the third scan sweep The instrument will discard the last two of the 10 readings and will Power Fails resume scanning at the beginning of the third scan sweep e f you remove a module or move a module to a different slot while power is off the scan will not resume when power is restored No error is generated e f you replace a module with a module of the same type while power is off the instrument will continue scanning when power is restored No error is generated 77 Chapter 4 Features and Functions Scanning Adding Channels to a Scan List Before you can initiate a scan you must configure the channels to be scanned and set up a scan list these two operations occur simultaneously from the front panel The instrument automatically scans the configured channels in ascending order from slot 100 through slot 300 To Build a Scan List From the Front Panel function range resolution and other measurement parameters for this channel You can also press to sequentially step through the s
103. low power As the power switched increases relay life deteriorates i 300V Maximum Switching Capacity 240V 9 180V 120V Voltage Switched 60V 0 2A 04A 06A 08A 1A Armature HP 34901A 34903A 34904A 34908A 10mA 20mA 30mA 40mA 50mA Reed HP 34902A Current Switched 400 Chapter 8 Tutorial Relay Life and Preventative Maintenance Switching Frequency Relay contacts heat up as they switch significant power The heat is dissipated through the leads and the body of the relay As you increase the switching frequency to near its maximum heat cannot dissipate before the next cycle The contact temperature rises and the life of the relay is reduced Replacement Strategy There are essentially two strategies that you can use for preventative maintenance of the relays on the switching modules The strategy that you choose depends upon your application the consequences of a relay failure in your system and the number of relay cycles during a measurement session The first strategy is to replace each relay as needed after it fails or becomes erratic This is suitable if you are switching higher loads on only a few relays on the module The disadvantage of this strategy is the inconvenience of continually replacing relays as they near the end of their life at different times The second strategy is to replace all relays on the module or simply purchase a new module as the relays near the end of
104. measurements on multiplexer channels You can also monitor a digital input port or the totalizer count on the multifunction module To disable monitoring press again 37 Interval Interval en Chapter 2 Front Panel Overview To Set a Scan Interval To Set a Scan Interval You can set the instrument s internal timer to automatically scan at a specific interval e g start a new scan sweep every 10 seconds or when an external TTL trigger pulse is received You can configure the instrument to scan continuously or to stop after sweeping through the scan list a specified number of times Select the interval scan mode For this example select the Interval Scan mode which allows you to set the time from the start of one scan sweep to the start of the next scan sweep Set the interval to any value between 0 and 99 hours INTERVAL SCAN Select the scan count You can specify the number of times that the instrument will sweep through the scan list the default is continuous When the specified number of sweeps have occurred the scan stops Set the scan count to any number between 1 and 50 000 scans or continuous onol SCANS 3 Run the scan and store the readings in memory Chapter 2 Front Panel Overview To Apply Mx B Scaling to Measurements To Apply Mx B Scaling to Measurements The scaling function allows you to apply a gain and offset to all readings on a specified multiplexer channel during a scan
105. memory This is an easy way to verify your wiring connections before initiating the scan Run the scan and store the readings in non volatile memory The instrument automatically scans the configured channels in consecutive order from slot 100 through slot 300 the SCAN annunciator turns on Channels that are not configured are skipped during the scan In the default configuration the instrument continuously scans the configured channels at a 10 second interval Press and hold to stop the scan View the data from the scan All readings taken during a scan are automatically time stamped and stored in non volatile memory During the scan the instrument calculates and stores the minimum maximum and average on all channels in the scan list You can read the contents of memory at any time even during a scan From the front panel data is available for the last 100 readings on each channel readings taken during a scan all of the data is available from the remote interface From the View menu select READINGS and press again Then press Cand L to choose the data you want to view for the selected channel as shown in the table below C and D Select Channel Last Reading on Channel Time of Last Reading Minimum Reading on Channel Time of Minimum Reading Maximum Reading on Channel Time of Maximum Reading Average of Readings on Channel Second Most Recent Reading on Channel Third Most Recent Reading on Channel J 99th Most
106. not at the same temperature an error will be created in the measurement 348 Chapter 8 Tutorial Measurement Fundamentals To make a more accurate measurement you should extend the copper test leads of the internal DMM closer to the measurement and hold the connections to the thermocouple at the same temperature Internal DMM Cu At Cu Fe O ye onde Measurement v cy Thermocouple J c Pa Qo a Cu a Cu Fe oo l nJ 2 7 t Ice Bath xs ae so Reference Thermocouple This circuit will give accurate temperature measurements However it is not very convenient to make two thermocouple connections and keep all connections at a known temperature The Law of Intermediate Metals eliminates the need for the extra connection This empirical law states that a third metal iron Fe in this example inserted between two dissimilar metals will have no effect upon the output voltage provided the junctions formed are at the same temperature Removing the reference thermocouple makes the connections much easier Internal DMM Cu o Cu Fe Measurement Thermocouple c Cu o Cu o Ene Ice Bath x lt E External Reference Junction This circuit is the best solution for accurate thermocouple connections 349 Chapter 8 Tutorial Measurement Fundamentals In some measurement situations however it would be nice to remove the need for an ice bath or any other fixed external r
107. of the table and columnIndex determines the column scan sweep count The number of comma delimited fields returned per channel is determined by the FORMat READing commands The number of fields per channel is required to locate the data in row 1 In this example there are three cells fields per channel Set up the heading while scanning the first channel f Channel 1 Then Label the top of the data column and time stamp column Howat Cells 4 columnIndex 2 Scan amp Str columnIndex Cells 4 columnIndex 2 Font Bold True Cells 3 columnIndex 2 1 time stamp Cells 4 columnIndex 2 1 min sec End If Get channel number put in column A for first scan only If columnIndex 1 Then Cells Channel 4 1 Cells 1 3 End If Get the reading data and put into the column Cells Channel 4 columniIndex 2 Cells 1 1 Get the time stamp and put into the column to the right of data to convert relative time to Excel time divide by 86400 Cells Channel 4 columnIndex 2 1 Cells 1 2 86400 Cells Channel 4 columniIndex 2 1 NumberFormat mm ss 0 End Sub Function ConvertTime TimeString As String As Date This routine will take the string returned from the SYSTem TIME SCAN command and return a number compatible with the Excel format When loaded into a cell it can be formatted using the Excel Format menu Dim timeNumber As Date
108. on the temperature measurement units currently selected e Front Panel Operation First select the temperature function on the active channel Then select the temperature units UNITS F e Remote Interface Operation UNIT TEMP F 103 106 Chapter 4 Features and Functions Temperature Measurement Configuration Thermocouple Measurements To connect a thermocouple to the module s screw terminals see page 21 The instrument supports the following thermocouple types B E J K N R S and T using ITS 90 software conversions The default is a J Type thermocouple Thermocouple measurements require a reference junction temperature For the reference junction temperature you can use an internal measurement on the module an external thermistor or RTD measurement or a known fixed junction temperature If you select an external reference the instrument automatically reserves channel 01 on the multiplexer in the lowest slot as the reference channel thermistor or RTD measurement If you have more than one multiplexer installed channel 01 on the module in the lowest slot is used as the reference for the entire instrument Before configuring a thermocouple channel with an external reference you must configure the reference channel channel 01 for a thermistor or RTD measurement An error is generated if you attempt to select the external reference source before configuring the reference channel An error is als
109. outside of the environmental speci fications for the product or improper site preparation or maintenance The design and implemen tation of any circuit on this product is the sole respon sibility of the Buyer HP does not warrant the Buyer s circuitry or malfunctions of HP products that result from the Buyer s circuitry In addition HP does not warrant any damage that occurs as a result of the Buyer s circuit or any defects that result from Buyer supplied products HP makes no other warranty expressed or implied whether written or oral with respect to this product and specifi cally disclaims any implied warranty or condition of merchant ability fitness for a particular purpose or satisfactory quality Manual Part Number 34970 90002 Microfiche Part Number 34970 99002 Exclusive Remedies The remedies provided herein are the Buyer s sole and exclusive remedies HP shall not be liable for any direct indirect special incidental or consequen tial damages including lost profit whether based on warranty contract tort or any other legal theory Notice The information contained in this document is subject to change without notice Hewlett Packard makes no warranty of any kind with regard to this material including but not limited to the implied warranties of merchantability and fit ness for a particular purpose Hewlett Packard shall not be liable for errors contained herein o
110. power on if you have configured the instrument using the PSc 0 command 277 Chapter 5 Remote Interface Reference The SCPI Status System Using Service Request SRQ and Serial Poll You must configure your computer to respond to the IEE E 488 service request SRQ interrupt to use this capability Use the Status Byte enable register SRE command to select which condition bits will assert the EEE 488 SRQ line If bit 6 RQS transitions from a 0 toa 1 then an EEE 488 service request message is sent to your computer The computer may then poll the instruments on the interface bus to identify which one is asserting the service request line the instrument with bit 6 set in its Serial Poll response Note When a Serial Poll is issued bit 6 RQS is cleared in the Status Byte no other bits are affected and the service request line is cleared To read the Status Byte condition register send an EEE 488 Serial Poll message Querying the condition register will return a decimal value which corresponds to the binary weighted sum of the bits set in the register Performing a Serial Poll will not affect measurement throughput Note Unlike other commands a Serial Poll is executed immediately Therefore the status indicated by a Serial Poll may not necessarily indicate the affect of the most recent command Use the OPC command to guarantee that commands previously sent to the instrument have completed before executin
111. ranges at lt 10 of range Up range at gt 120 of range 215 Chapter 5 Remote Interface Reference Setting the Function Range and Resolution SENSe VOLTage DC RANGe AUTO lt ch_list gt VOLTage AC RANGe AUTO lt ch_list gt RESistance RANGe AUTO lt ch_list gt FRESistance RANGe AUTO lt ch_list gt CURRent DC RANGe AUTO lt ch_list gt CURRent AC RANGe AUTO lt ch_list gt FREQuency VOLTage RANGe AUTO lt ch_list gt PERiod VOLTage RANGe AUTO lt ch_list gt Query the autorange setting on the specified channels Returns 0 OFF or 1 ON SENSe VOLTage DC RESolution lt resolution gt MIN MAX lt ch_list gt RESistance RESolution lt resolution gt MIN MAX lt ch_list gt FRESistance RESolution lt resolution gt MIN MAX lt ch_list gt CURRent DC RESolution lt resolution gt MIN MAX lt ch_list gt Select the resolution for the function selected on the specified channels Specify the resolution in the same units as the measurement function not in number of digits MIN selects the smallest value accepted for this parameter which gives the most resolution MAX selects the largest value accepted for this parameter which gives the least resolution For more information on the relationship between integration time measurement resolution number of digits and number of bits see the t
112. rates up to 600 readings per second on a single channel and scan rates up to 250 channels per second Choice of multiplexing matrix general purpose Form C switching RF switching digital I O totalize and 16 bit analog output functions HP IB IEEE 488 interface and RS 232 interface are standard SCPI Standard Commands for Programmable Instruments compatibility HP 34970A Data Acquisition Switch Unit The Front Panel at a Glance 9 Control Open Read Configure 3 Measure interval 4 ee Mx B Step 8 1 5 Alarm Advanced Card Reset Alarm Out Utility HEWLETT 34970A VW PACKARD DATA ACQUISTION SWITCH UNIT Sto Rel Interface OM Configure Measure Interval fey ra Alarm Advanced Alarm Out Utility Control Close Write AS 7 Reset Noo hOND State Storage Remote Interface Menus Scan Start Stop Key Measurement Configuration Menu Scaling Configuration Menu Alarm Alarm Output Configuration Menu Scan to Scan Interval Menu Scan List Single Step Read Key Denotes a menu key See the next page for details on menu operation 8 Advanced Measurement Utility Menus 9 Low Level Module Control Keys 10 Single Channel Monitor On Off Key 11 View Scanned Data Alarms Errors Menu 12 Shift Local Key 1
113. reactive loads Although many types of contact protection networks can be used only RC networks and varistors are described in this section E D i 1 a Relay H Contact Varistor 1 a i a Rp Ii xp 8 RL 2 RC Protection Networks When designing RC protection networks the protection resistor Rp is selected as a compromise between two resistance values The minimum value of Rp is determined by the maximum acceptable relay contact current Imax For the HP 34903A the maximum allowable relay current Imax is 1A de or acrms Thus the minimum value for Rp is V Io where V is the peak value of the supply voltage a 385 Chapter 8 Tutorial Actuators and General Purpose Switching The maximum value for Rp is usually made equal to the load resistance Ry Therefore the limits on Rp can be stated as V max i lt Rp lt RL Note that the actual value of the current Io in a circuit is determined by the equation i V o R Where V is the peak value of the source voltage and Ry is the resistance of the load The value for Io will be used to determine the value of the protection capacitor Cp In determining the value of the protection network capacitor Cp there are several things that you will need to consider First the total circuit capacitance Cot must be such that the peak voltage across the open relay contacts does not exceed 300 Vrms The equation for d
114. returns a list of channel numbers in the SCPI definite length block format The response begins with the character followed by a single character representing the number of succeeding characters to interpret as a length specifier followed by a length specifier representing the number of bytes in the block followed by a block of that many bytes An empty scan list one with no channels selected will be 13 For example if you send ROUT SCAN 101 103 the ROUT SCAN command will return the following 214 101 102 103 ROUTe SCAN SIZE Query the number of channels in the scan list Returns a value between 0 and 120 channels TRIGger SOURce BUS IMMediate EXTernal TIMer SOURce Select the trigger source to control the onset of each sweep through the scan list a sweep is one pass through the scan list The selected source is used for all channels in the scan list The instrument will accept a software bus command an immediate continuous scan trigger an external TTL trigger pulse or an internally paced timer The default is TIMer The SOUR query returns the present scan trigger source Returns BUS IMM EXT or TIM 240 Chapter 5 Remote Interface Reference Scanning With an External Instrument TRIGger TIMer lt seconds gt MIN MAX TIMer Set the scan to scan interval in seconds for measurements on the channels in the scan list This command defin
115. scan list The default DEF transducer type is a 5 kQ thermistor 211 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands CONFigure VOLTage DC CONF igure VOLTage AC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for dc or ac voltage measurements but do not initiate the scan Note that this command also redefines the scan list For ac measurements the resolution is actually fixed at 6 digits the resolution parameter only affects the number of digits shown on the front panel CONFigure RESistance CONFigure FRESistance lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for 2 wire or 4 wire measurements but do not initiate the scan Note that this command also redefines the scan list For 4 wire measurements FRES the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections F or example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel CONF igure CURRent DC CONF igure CURRent AC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt
116. setting 145 setting the 22 145 time stamp absolute 87 relative 87 timeout low frequency 118 torroid 339 totalize threshold 135 hardware jumper 395 TOT CLEar IMMediate command 257 TOT DATA command 257 TOT SLOPe command 257 TOT TYPE command 256 257 totalizer ac vs TTL threshold 135 adding to scan list 44 136 block diagram 395 clearing the count 136 contact bounce 396 counting on falling edge 135 counting on rising edge 135 errors 396 gate signal 135 396 manually reset 44 maximum count 136 395 overflow 280 reading count 44 reset mode 44 76 136 reset mode while scanning 76 scanning 76 Totalize Threshold jumper 135 track mode alarm output lines 128 transducer types 56 tree switch 383 triangle brackets lt gt syntax 73 181 TRIG SOUR command 81 TRIG TIMer command 81 TRIGGER command 82 TRIGger COUNt command 86 229 241 TRIGger SOUR command 228 240 TRIGger TIMer command 229 241 triggering buffering 83 external 83 scan 80 troubleshooting error messages 303 318 RS 232 273 true RMS 360 TTL drive digital output 393 tutorial 333 twisted pair cables 55 two wire multiplexers 58 378 two wire ohms 369 432 Index U UNIT TEMP command 106 219 units temperature 106 219 with readings 87 unsecure calibration 156 Utility key 36 Vv varistor 386 vertical bar syntax 73 181 VIEW annunciator 4 View key 24 36
117. slot number 100 200 or 300 and ce is the channel number You can specify a single channel multiple channels or a range of channels as shown below e The following command configures a scan list to include only channel 10 on the module in slot 300 ROUT SCAN 310 e The following command configures a scan list to include multiple channels on the module in slot 200 The scan list now contains only channels 10 12 and 15 the scan list is redefined each time you send anew ROUTe SCAN command ROUT SCAN 210 212 215 e The following command configures a scan list to include a range of channels When you specify a range of channels the range may contain invalid channels they are ignored but the first and last channel in the range must be valid The scan list now contains channels 5 through 10 slot 100 and channel 15 slot 200 ROUT SCAN 105 110 215 73 Chapter 4 Features and Functions Scanning Scanning The instrument allows you to combine a DMM eather internal or external with multiplexer channels to create a scan During a scan the instrument connects the DMM to the configured multiplexer channels one at a time and makes a measurement on each channel Any channel that can be read by the instrument can also be included in ascan This includes any combination of temperature voltage resistance current frequency or period measurements on multiplexer channels A scan can also include a read of
118. stores readings in memory Use the FETCh command to retrieve stored readings from memory the readings are not erased when you read them e Front Panel Operation From the front panel data is available for the last 100 readings on each channel readings taken during a scan all of the data is available from the remote interface After turning the knob to the desired channel press the and D keys to choose the data that you want to view for the selected channel as shown below the LAST MIN MAX and AVG annunciators turn on to indicate what data is currently being viewed Reading memory is not cleared when you read it Note that you can view readings from the front panel even while the instrument is in remote READINGS GC and D Select Channel Last Reading on Channel Time of Last Reading Minimum Reading on Channel Time of Minimum Reading Maximum Reading on Channel Time of Maximum Reading Average of Readings on Channel Second Most Recent Reading on Channel Third Most Recent Reading on Channel 4 99th Most Recent Reading on Channel 91 Chapter 4 Features and Functions Scanning Remote Interface Operation The following command retrieves stored readings from memory the readings are not erased FETCH Use the following commands to query the statistics on the readings stored in memory for a specific channel These commands do not remove the data from memory CALC AVER MIN 305 Min
119. that the internal DMM can detect for a given measurement Sensitivity defines the ability of the internal DMM to respond to small changes in the input level For example suppose you are monitoring a 1 mVdc signal and you want to adjust the level to within 1 uV To be able to respond to an adjustment this small this measurement would require a multimeter with a sensitivity of at least 1 uV You could use a 64 digit multimeter if it has a 1 Vdc or smaller range You could also use a 4 digit multimeter with a 10 mVdc range For ac voltage and ac current measurements note that the smallest value that can be measured is different from the sensitivity For the internal DMM these functions are specified to measure down to 1 of the selected range For example the internal DMM can measure down to 1 mV on the 100 mV range 416 Chapter 9 Specifications Interpreting Internal DMM Specifications Resolution Resolution is the numeric ratio of the maximum displayed value divided by the minimum displayed value on a selected range Resolution is often expressed in percent parts per million ppm counts or bits For example a 62 digit multimeter with 20 overrange capability can display a measurement with up to 1 200 000 counts of resolution This corresponds to about 0 0001 1 ppm of full scale or 21 bits including the sign bit All four specifications are equivalent Accuracy Accuracy is a measure of the exactness to which the
120. that were parallel in the undeformed state Poisson Strain v measures a property of materials known as tooo m the Poisson Ratio It is the F 4m F negative ratio of transverse and TARE TE longitudinal normal strain D 4D when a body has a longitudinal L AL tensile force applied v 8 e where e AD D and e AL L Stress Stress is a term used to compare the loading applied to a material with its ability to carry the load Stress o in a material can not be measured directly it must be computed from material properties and measurable quantities such as strain and force 373 Chapter 8 Tutorial Measurement Fundamentals For more information on strain gages refer to Practical Strain Gage Measurements HP Application Note 290 1 This application note is also available on the HP Website in the Test and Measurement section www hp com Strain Sensors The metal foil resistance strain gage is by far the most widely used strain measurement sensor It consists of a thin metallic foil grid bonded to a thin insulating adhesive backing The resistance of the foil varies linearly with strain Strain in the test body is simply the ratio of the foil s strained to unstrained resistance AR R The Gage Factor GF indicates the sensitivity of a strain gage and isa measure of the fractional resistance change per strain GF AR R e Devices with a higher gage factor will exhibit a greate
121. the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel MEASure CURRent DC MEASure CURRent AC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Note Current measurements are allowed only on channels 21 and 22 on the HP 34901A multiplexer module Configure the specified channels for dc or ac current measurements and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory F or ac measurements the resolution is actually fixed at 61 digits the resolution parameter only affects the number of digits shown on the front panel MEASure FREQuency MEASure PERiod lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for frequency or period measurements and immediately sweep through the scan list one time Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory With no signal applied O is returned 209 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands
122. the active channel choose the following item Ro 100 000 0 OHM To select the RTD type a 0 00385 or 0 00391 for the active channel choose the following item ALPHA 0 00385 110 Chapter 4 Features and Functions Temperature Measurement Configuration e Remote Interface Operation You can use the MEASure or CONFigure command to select the probe type and RTD type For example the following statement configures channel 301 for 2 wire measurements of an RTD with a 0 00385 use 85 to specify a 0 00385 or 91 to specify a 0 00391 CONF TEMP RTD 85 301 You can also use the SENSe command to select the probe type RTD type and nominal resistance F or example the following statement configures channel 103 for 4 wire measurements of an RTD with 0 00391 channel 103 is automatically paired with channel 113 for the 4 wire measurement SENS TEMP TRAN FRTD TYPE 91 103 The following statement sets the nominal resistance Ro to 1000Q on channel 103 SENS TEMP TRAN FRTD RES 1000 103 111 Chapter 4 Features and Functions Temperature Measurement Configuration Thermistor Measurements To connect a thermistor to the module s screw terminals see page 21 e Theinstrument supports 2 2 kQ 44004 5 kQ 44007 and 10 kQ 44006 thermistors e Front Panel Operation To select the thermistor function for the active channel choose the following i
123. the specified alarm limits is logged in memory You can store up to 50 000 readings in memory during a scan You can read the contents of reading memory at any time even during a scan Reading memory is not cleared when you read it 2 As alarm events are generated they are also logged in an alarm queue which is separate from reading memory This is the only place where non scanned alarms get logged alarms during a monitor alarms generated by the multifunction module etc Up to 20 alarms can be logged in the alarm queue If more than 20 alarm events are generated they will be lost only the first 20 alarms are saved Even if the alarm queue is full the alarm status is still stored in reading memory during a scan The alarm queue is cleared by the cLs dear status command when power is cycled and by reading all of the entries A Factory Reset RST command does not clear the alarm queue 122 Chapter 4 Features and Functions Alarm Limits e You can assign an alarm to any configured channel and multiple channels can be assigned to the same alarm number However you cannot assign alarms on a specific channel to more than one alarm number e When an alarm occurs the instrument stores relevant information about the alarm in the queue This includes the reading that caused the alarm the time of day and date of the alarm and the channel number on which the alarm occurred The information stored in the alarm queue is always i
124. their life This strategy is best suited for those applications where all relays on the module are switching similar loads The failure of several relays over a relatively short period of time may indicate impending failures on other relays switching similar loads This strategy decreases the risk of failure during actual use at the expense of replacing some relays that may have useful life remaining Note In both cases described above you can use the HP 34970A Relay Maintenance System to track and even predict relay failures 401 e DC Resistance and Temperature Accuracy Specifications on page 404 e DC Measurement and Operating Characteristics on page 405 e AC Accuracy Specifications on page 406 e AC Measurement and Operating Characteristics on page 407 e Measurement Rates and System Characteristics on page 408 e Module Specifications HP 34901A 34902A 34908A 34903A 34904A on page 409 HP 34905A 34906A on page 410 Typical AC Performance Graphs on page 411 HP 34907A on page 412 e HP BenchLink Data Logger Software Specifications on page 412 e Product and Module Dimensions on page 413 e To Calculate Total Measurement Error on page 414 e Interpreting Internal DMM Specifications on page 416 e Configuring for Highest Accuracy Measurements on page 419 Specifications E DC Resistance and Temperature Accuracy Specifications Chapter 9 Specifications DC Resistance and Temperature Accuracy Specificat
125. warm up at calibration temperature 1 C and lt 10 minutes add 0 0002 range additional error 5 uV RTD 0 00385 DIN and 0 00392 Thermistor 44004 44007 44006 series Settling Considerations Reading settling times are affected by source impedance low dielectric absorption characteristics and input signal changes Measurement Noise Rejection 60 Hz 50 Hz l DC CMRR Integration Time 140 dB Normal Mode Rejection 1 300 Vdc isolation voltage ch ch ch earth 2 For 1 kQ unbalance in LO lead 3 For power line frequency 0 1 200 PLC 3 33s 4s 110 dB l4 4 For power line frequency 1 use 80 dB 100 PLC 1 67s 2s 105 dB I For power line frequency 3 use 60 dB 20 PLC 333 ms 400 ms 100 dB 41 5 Reading speeds for 60 Hz and 50 Hz operation autozero OFF 10 PLC 167 ms 200 ms 95 aB 4I 6 61 digits 22 bits 51 digits 18 bits 412 digits 15 bits 2 PLC 33 3 ms 40 ms 90 dB 7 Add 20 uV for DCV 4 pA for DCI or 20 mQ for resistance 1 PLC 16 7 ms 20 ms 60 dB 8 For fixed function and range readings to memory lt 1PLC 0 dB scaling and alarms off autozero OFF 405 Chapter 9 Specifications AC Accuracy Specifications E AC Accuracy Specifications of reading of range Includes measurement error switching error and transducer conversion error Temperature Function Range Frequen
126. 0 maintenance clearing relay count 148 reading relay count 147 399 matrix switching combining 388 MAX annunciator 4 maximum reading during scan 75 Measure key 23 24 35 36 78 MEASure command 79 default settings 201 description 202 example 205 range parameter 207 resolution parameter 207 syntax statements 207 Measurement Complete signal 95 measurement error calculating 414 measurement range autorange 98 command syntax 215 overload 98 selecting 99 measurement resolution half digit 100 command syntax 216 selecting 101 vs integration time 103 203 measurement speeds scanning 405 measurement tutorial 333 medium ac filter 114 116 361 medium timeout 118 MEM annunciator 4 memory overflow 280 reading scanned readings 90 threshold status register 391 viewing alarm data 126 viewing scanned data 24 MEM NSTates command 263 MEM STATe DELete command 262 MEM STATe NAME command 262 MEM STATe RECal1 AUTO command 263 MEM STATe VALid command 263 menus front panel 3 33 summary 35 message available 279 message calibration 158 front panel display 144 errors 303 318 Microsoft Visual C 328 microwave switches driving 394 MIN annunciator 4 minimum reading during scan 75 modem auto answer 274 connection to 274 echo commands 274 flow control mode RS 282 154 result codes 274 module description HP 34901A 164 HP 34902A 1
127. 0 range or any positive error number in chapter 6 4 Execution Error 16 An execution error occurred see error numbers in the 200 range in chapter 6 5 Command Error 32 A command syntax error occurred see error numbers in the 100 range in chapter 6 6 Not Used 64 Returns 0 7 Power On 128 Power has been turned off and on since the last time the event register was read or cleared 282 Chapter 5 Remote Interface Reference The SCPI Status System The Standard event register is cleared when e You execute the cLs clear status command e You query the event register using the ESR command The Standard Event enable register is cleared when e You executethe ESE 0 command e You turn the power on and have previously configured the instrument to clear the enable register using the PSc 1 command Note that the enable register will not be cleared at power on if you have configured the instrument using the PSc 0 command 283 Chapter 5 Remote Interface Reference The SCPI Status System The Alarm Register The Alarm register group is used to report the status of the four instrument alarm limits Any or all of these alarm conditions can be reported to the Alarm Register summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the STATus ALARm ENABle command Bit Definitions Alarm Register
128. 00 300 ALL Reset the module in the specified slot to its power on state CPON means card power on To reset all three slots specify ALL This is equivalent to pressing from the front panel 267 Chapter 5 Remote Interface Reference System Related Commands SYSTem ERRor Query the instrument s error queue A record of up to 10 errors is stored in the instrument s error queue Errors are retrieved in first in first out FIFO order The first error returned is the first error that was stored When you have read all errors from the queue the ERROR annunciator turns off and the errors are cleared The error queue is cleared by the CLS dear status command or when power is cycled The errors are also cleared when you read the queue See chapter 6 for a complete listing of the HP 34970A error messages SYSTem ALARm Read the alarm data from the alarm queue one alarm event is read and cleared each time this command is executed The following is an example of an alarm stored in the alarm queue if no alarm data is in the queue the command returns 0 for each field 3 10090000E 01 C 1997 05 01 14 39 40 058 101 2 1 gt o o oes 1 Reading with Units 31 009 C 4 Channel Number 2 Date May 1 1997 5 Limit Threshold Crossed 0 No Alarm 3 Time 2 39 40 058 PM 1 LO 2 Hl 6 Alarm Number Reported 1 2 3 or 4 SYSTem VERSion Query the instrument to determine the present SC
129. 00 000 PRO DUE erta Input Signal Level Example Computing Total Measurement Error Assume that a 5 Vdc signal is input to the DMM on the 10 Vdc range Compute the total measurement error using the 90 day accuracy specification of 0 0020 of reading 0 0005 of range Reading Error 0 0020 x 5Vde 100 uV Range Error 0 0005 x 10 Vdc 50 uV Total Error 100 uV 50V 150 uV 0 0030 of 5 Vdc 30 ppm of 5 Vdc 415 Chapter 9 Specifications Interpreting Internal DMM Specifications Interpreting Internal DMM Specifications This section is provided to give you a better understanding of the terminology used and will help you interpret the internal DMM s specifications Number of Digits and Overrange The number of digits specification is the most fundamental and sometimes the most confusing characteristic of a multimeter The number of digits is equal to the maximum number of 9 s the multimeter can measure or display This indicates the number of full digits Most multimeters have the ability to overrange and add a partial or 14 digit For example the internal DMM can measure 9 99999 Vdc on the 10 V range This represents six full digits of resolution The internal DMM can also overrange on the 10 V range and measure up to a maximum of 12 00000 Vdc This corresponds to a 64 digit measurement with 20 overrange capability Sensitivity Sensitivity is the minimum level
130. 0000 017 101 2 4 1 Reading with Units 26 195 C 3 Channel Number 2 Time Since Start of Scan 17 ms 4 Alarm Limit Threshold Crossed 0 No Alarm 1 LO 2 Hl FORMat READing ALARm OFF ON READing ALARm Disable default or enable the inclusion of alarm data with data produced by READ FETCh or other queries of scan results This command operates in conjunction with the other FORMat READing commands they are not mutually exclusive The ALAR query reads whether or not alarm data is included Returns 0 OFF or 1 ON FORMat READing CHANnel OFF ON READing CHANnel Disable default or enable the inclusion of the channel number with data produced by READ FETCh or other queries of scan results This command operates in conjunction with the other FORMat READing commands they are not mutually exclusive The CHAN query reads whether or not the channel is included Returns 0 OFF or 1 ON 231 Chapter 5 Remote Interface Reference Scanning Overview FORMat READing TIME OFF ON READing TIME Disable default or enable the inclusion of a time stamp with data produced by READ FETCh or other queries of scan results This command operates in conjunction with the other FORMat READing commands they are not mutually exclusive Use the FORMat READ TIME TYPE command see below to select
131. 1 after selecting the external reference source on a thermocouple channel 312 501 502 511 512 513 514 521 522 532 540 550 Chapter 6 Error Messages Instrument Errors T O processor isolator framing error I O processor isolator overrun error Communications RS 232 framing error Communications RS 232 overrun err or Communications RS 232 parity error RS 232 only unable to execute using HP IB There are three commands which are allowed only with the RS 232 interface SYSTem LOCal SYSTem REMote and SYSTem RWLock Communications input buffer overflow Communications output buffer overflow Not able to achieve requested resolution The instrument cannot achieve the requested measurement resolution You may have specified an invalid resolution in the CONFigure or MEASure command Not able to null channel in overload The instrument cannot store an overload reading 9 90000000E 37 as the offset for Mx B scaling using a null Not able to execute command in local The instrument has received a READ or MI measurement mode EASure command while in the local mode 313 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 Chapter 6 Error Messages Self Test Errors Self Test Errors The following errors indicate failures that may occur during a self test Refer to the HP 34970A Service Gu
132. 134 Channel list empty scan list Before you can initiate a scan you must set up a scan list which includes all configured multiplexer or digital channels in the instrument Use the MEASure CONFigure or ROUTe SCAN commands to set up your scan list Memory lost stored state This error is reported at power on to indicate that a stored state has become unusable This error is most likely caused by a dead battery memory is battery backed Refer to the HP 34970A Service Guide to replace the internal battery Memory lost power on state This error is reported at power on to indicate that the power down state of the instrument normally recalled when power is turned on has become unusable This error is most likely caused by a dead battery memory is battery backed Refer to the HP 34970A Service Guide to replace the internal battery Memory lost stored readings This error is reported at power on to indicate that readings stored in memory from a previous scan have been lost This error is most likely caused by a dead battery memory is battery backed Refer to the HP 34970A Service Guide to replace the internal battery Memory lost time and date This error is reported at power on to indicate that the time and date settings have been lost they are reset to JAN 1 1996 00 00 00 This error is most likely caused by a dead battery memory is battery backed Refer to the HP 34970A Service Guide to replace the internal bat
133. 16 bit word only if neither port is in the scan list If one or both ports are included in the scan list you can read only one 8 bit port at a time However if you have included both ports in the scan list the data will be read from both ports simultaneously and will have the same time stamp Therefore you can externally combine the two 8 bit quantities into a 16 bit quantity From the front panel only you can specify whether you want to use binary or decimal format readings are always stored in memory in decimal format Once you have selected the number base it is used for all input or output operations on the same port You can monitor a digital input channel even if the channel is not part of the scan list the internal DMM is not required either A Factory Reset RST command Instrument Preset SySTem PRESet command and Card Reset SYSTem CPON command from the remote interface will reconfigure both ports as input ports Note that a from the front panel resets only the port currently selected both ports are not reset 133 Chapter 4 Features and Functions Digital Input Operations e Front Panel Operation After selecting the port press to read the bit pattern the least significant bit is on the right The bit pattern read from the port will be displayed until you press another key turn the knob or until the display times out Toadd a digital read to a scan list choose the following item DIO READ
134. 2 0 0005 1 000000 A lt 2V 0 050 0 006 0 080 0 010 0 100 0 010 0 005 0 0010 Temperature Type Best Range Accuracy Extended Range Accuracy P Thermocouple B 1100 C to 1820 C 1 2 C 400 C to 1100 C 1 8 C 0 03 C E 150 C to 1000 C 1 0 C 260 C to 150 C 1 5 C 0 03 C J 150 C to 1200 C 1 0 C 210 C to 150 C 1 2 C 0 03 C K 100 C to 600 C 1 0 C 230 C to 100 C 1 5 C 0 03 C N 100 C to 1300 C 1 0 C 220 C to 100 C 1 5 C 0 03 C R 300 C to 1760 C 1 2 C 50 C to 300 C 1 8 C 0 03 C S 400 C to 1760 C 1 2 C 50 C to 400 C 1 8 C 0 03 C T 100 C to 400 C 1 0 C 240 C to 100 C 1 5 C 0 03 C RTD Ro from 499 200 C to 600 C 0 06 C 0 003 C to 2 1 ka Thermistor 2 2 k 5k 10k 80 C to 150 C 0 08 C 0 002 C 1 Specifications are for 1 hour warm up and 61 digits 2 Relative to calibration standards 3 20 over range on all ranges except 300 Vdc and 1 Adc ranges 4 Specifications are for 4 wire ohms function or 2 wire ohms using Scaling to remove the offset Without Scaling add 1Q additional error in 2 wire ohms function 5 1 year accuracy For total measurement accuracy add temperature probe error 404 Chapter 9 Specifications DC Measurement and Operating Characteristics E DC Measurement and Operating Characteristics DC Measurement Characteristics DC Operating Characteristics DC Voltage Measurement Method A D Linearity Input
135. 2 TEMP TRAN RTD TYPE command 222 TEMP TRAN TC CHECk command 221 TEMP TRAN TC RJUN command 221 TEMP TRAN THER TYPE command 222 TEMP TRAN TC RJUN TYPE command 220 TEMP TRAN TC TYPE command 220 TEMP TRAN TYPE command 219 temperature coefficient 366 temperature conversion accuracy 345 temperature measurements RTDs 110 thermistors 112 thermocouples 107 temperature units 106 temperature product operating 408 terminal connections ac current 21 ac voltage 21 ac current 21 dc voltage 21 frequency 21 period 21 resistance 21 RTDs 21 thermistors 21 thermocouples 21 wire strain relief 20 wire strip length 20 thermal EMF errors 340 thermocouple metals used 351 thermistors connections 21 conversion accuracy 345 measurement tutorial 112 346 measurement units 106 types supported 21 106 Thermocouple Check feature 107 221 thermocouples calculation error 353 color codes 351 conversion accuracy 345 connections 21 diffusion error 352 external reference 107 fixed reference 107 internal reference 107 isothermal block 107 measurement tutorial 347 measurement units 106 probe accuracy 351 reference junction 107 reference junction error 352 shielding 353 shunt impedance 353 temperature range 351 Thermocouple Check 107 221 types supported 21 106 351 thermoelectric voltages 340 threshold totalize 135 136 187 time clock factory
136. 3 GHz 10 MHz 100 MHz 1 GHz 3 GHz 391 Chapter 8 Tutorial Multifunction Module Multifunction Module Digital Input The HP 34907A module has two non isolated 8 bit input output ports which you can use for reading digital patterns e You can read the live status of the bits on the port or you can configure a scan to include a digital read e You can generate an alarm when a specific bit pattern or bit pattern change is detected on an input channel The channels do not have to be part of the scan list to generate an alarm e The internal 5V pull up circuitry allows you to use the digital input to detect contact closures like micro switches or limit switches An open input floats to 5V and is read as a 1 An input shorted to ground is read as a 0 An example of a contact closure detection channel is shown below 5 V g lt 10 kQ an I O Line 1 of 8 a l i f l lt 7 TTL Digital Read Reference O 621v V X Limit Switch 392 Chapter 8 Tutorial Multifunction Module Digital Output The HP 34907A module has two non isolated 8 bit input output ports which you can use for outputting digital patterns You can combine the two ports to output a 16 bit word A simplified diagram of a single output bit is shown below External Circuit 5 V av 10 ko i of utput e O gt VOLie i 1of16 i ZER lt 0 2 A Jd i 2 V Lesaga e Each outp
137. 3 Knob 14 Navigation Arrow Keys Interface Interface Interface The Front Panel Menus at a Glance Several of the front panel keys guide you through menus to configure various parameters of the instrument see previous page The following steps demonstrate the menu structure using the key t HPIB H88 ADDRESS 09 1 Press the menu key You are automatically guided to the first level of the menu Rotate the knob to view the other choices on the first level of the menu The menu will automatically timeout after about 20 seconds of inactivity You will be returned to the operation in progress prior to entering the menu Press the same menu key again to move to the next item of the menu Typically this is where you choose parameter values for the selected operation Rotate the knob to view the choices on this level of the menu When you reach the end of the list rotate the knob in the opposite direction to view all of the other choices The current selection is highlighted for emphasis All other choices are dimmed Press the same menu key again to accept the change and exit the menu A brief confirmation message is displayed Tip To review the current configuration of a specific menu press the menu key several times A message NO CHANGES is displayed when you exit the menu Display Annunciators MEQ HEWLETT 34970A PZB PACKARD DATA ACQUISTION SWITCH
138. 5 746 747 748 749 Chapter 6 Error Messages Calibration Errors Cal Cal Cal Cal Cal Cal Cal Cal Cal Cal Cal Cal Cal Cal full scale correction out of range DCV offset out of range DCI offset out of range RES offset out of range FRES offset out of range extended resistance self cal failed 300V DC correction out of range precharge DAC convergence failed A D turnover correction out of range AC flatness DAC convergence failed AC low frequency convergence failed AC low frequency correction out of range AC rms converter noise correction out of range AC rms 100th scale correction out of range Cal data lost secure state Cal data lost string data Cal data lost DCV corrections Cal data lost DCI corrections Cal data lost RES corrections Cal data lost FRES corrections Cal data lost AC corrections Config data lost HP IB address Config data lost RS 232 DMM relay count data lost 316 901 902 903 904 905 906 907 908 910 911 912 913 914 915 916 Chapter 6 Error Messages Plug In Module Errors Plug In Module Errors Module hardware unexpected data received Module hardware missing stop bit Module hardware data overrun Module hardware protocol violation Module hardware early end of data Module hardware missing end of data Module hardware module srq signal stuck low Module hardware not responding Module reported an unknown module type Module reported co
139. 6 carrying handle adjusting 29 removing 29 celsius setting units 106 Channel Advance external scanning connector 5 operation 96 Channel Closed external scanning connector 5 operation 96 channel configuration copying 25 front panel 23 channel delay automatic 89 default values 88 defined 88 settings 88 channel list parameters 301 channel list building from front panel 78 building from remote 79 examples 73 181 rules 73 181 channel number with readings 87 channel numbering 23 422 Index channel numbering HP 34901A 164 HP 34902A 166 HP 34903A 168 HP 34904A 170 HP 34905A 172 HP 34906A 172 HP 34907A 174 HP 34908A 176 chassis ground 5 clearing reading memory 75 clock factory setting 145 setting the 22 145 Close key 26 coaxial cables 55 338 coefficient temperature 366 color codes thermocouples 351 COM serial ports 273 command summary SCPI 181 200 command syntax SCPI conventions 73 181 command syntax 299 version query 149 common LO multiplexers 58 378 common mode noise 353 condition register status 275 CONFigure command 79 default settings 201 description 202 example 205 range parameter 207 resolution parameter 207 syntax statements 211 CONFigure command 213 connections 2 wire resistance 21 4 wire resistance 21 ac current 21 ac voltage 21 de current 21 de voltage 21 frequency 21 period 21 RTD
140. 66 HP 34903A 168 HP 34904A 170 HP 34905A 172 HP 34906A 172 HP 34907A 174 HP 34908A 176 module information connecting wiring 20 default settings 162 dimensions 413 firmware revision 146 installing in mainframe 20 reading relay count 147 specifications 409 strain relief 20 MON annunciator 4 Mon key 37 94 Monitor function definition 93 scan on alarm 84 94 while scanning 75 with alarms 93 with Mx B scaling 93 multiplexer types 378 multiplexers errors 381 four wire 58 380 one wire single ended 58 378 two wire 58 378 VHF 58 Mx B key 35 39 Mx B scaling custom label 39 120 default gain M 121 default offset B 121 equation used 119 interaction with alarms 119 null stored as offset 119 setting gain M 39 121 setting offset B 39 121 strain measurements 375 valid gain M values 120 valid offset B values 120 while scanning 75 119 427 Index N name stored states 48 noise caused by ground loops 341 noise rejection normal mode 103 nominal impedance cabling 335 nominal resistance RTD default 110 222 values 110 222 normal mode rejection 103 344 405 NPLC 103 344 405 command syntax 218 vs channel delays 89 null stored as offset Mx B 119 number of bits vs integration time 103 203 number of digits 100 416 vs integration time 103 203 numeric parameters 300 oO OC a
141. 7 external scanning connections 95 with digital channels 97 external trigger connector 5 83 95 scan interval 80 F factory reset state 160 fahrenheit setting units 106 fast ac filter 114 116 361 fast timeout 118 FETCh command description 79 204 236 example 206 filler panel kit rack mounting 31 filter ac signal 114 116 117 361 firmware revision HP 34970A 146 plug in modules 146 fixed input range dc voltage 113 fixed reference thermocouple 107 fixed reference junction 221 flange kit rack mounting 31 floppy disks BenchLink 19 flow mode RS 232 DTR DSR mode 153 factory setting 47 153 Modem mode 154 None no flow mode 153 RTS CTS mode 153 selecting 47 153 XON XOFF mode 153 form C SPDT switching 59 384 format alarm queue data 127 scanned readings 87 424 Index FORMat READ ALARm command 231 FORMat READ CHANNnel command 231 FORMat READ TIME command 232 264 FORMat READ UNIT command 232 four wire multiplexers 58 380 four wire ohms 115 369 four wire pairing RTD 110 FREQ RANGe LOWer command 225 frequency measurements low frequency timeout 118 sources of error 377 connections 21 front panel annunciators 4 defining scan list 23 layout 2 menu overview 3 33 front panel display enable disable 144 text message 144 fuse location 5 28 part number 27 replacing 28 factory setting 27 fuseholder as
142. 700E 02 SENSe FREQuency APERture 0 01 0 1 1 MIN MAX lt ch_list gt PERiod APERture 0 01 0 1 1 MIN MAX lt ch_list gt Select the aperture time or gate time for frequency or period measurements on the specified channels Specify 10 ms 4 digits 100 ms default 5 digits or 1 second 6 digits MIN 0 01 seconds MAX 1 second SENSe FREQuency APERture lt ch_list gt MIN MAX PERiod APERture lt ch_list gt MIN MAX Query the aperture time for frequency or period measurements on the specified channels Returns a number in the form 1 00000000E 01 217 Chapter 5 Remote Interface Reference Setting the Function Range and Resolution SENSe TEMPerature NPLC 0 02 VOLTage DC NPLC 0 02 RESistance NPLC 0 02 FRESistance NPLC 0 02 CURRent DC NPLC 0 02 0 0 2 2 1 1 2 2 10 10 10 10 10 100 100 100 100 100 200 200 200 200 200 MIN MIN MIN MIN MIN MAX MAX MAX MAX MAX lt ch_list gt lt ch_list gt lt ch_list gt lt ch_list gt lt ch_list gt Set the integration time in number of power line cycles PLCs on the specified channels The default is 1 PLC MIN 0 02 MAX 200 For more information on the relationship between integration time measurement resolution number of digits an
143. 9 e System Related Operations starting on page 140 e Remote Interface Configuration starting on page 150 e Calibration Overview starting on page 155 e Factory Reset State on page 160 e Instrument Preset State on page 161 e Multiplexer Module Default Settings on page 162 e Module Overview on page 163 e HP 34901A 20 Channel Multiplexer starting on page 164 e HP 34902A 16 Channel Multiplexer starting on page 166 e HP 34903A 20 Channel Actuator starting on page 168 e HP 34904A 4x8 Matrix Switch starting on page 170 e HP 34905A 6A Dual 4 Channel RF Multiplexers starting on page 172 e HP 34907A Multifunction Module starting on page 174 e HP 34908A 40 Channe Single Ended Multiplexer starting on page 176 72 Chapter 4 Features and Functions SCPI Language Conventions SCPI Language Conventions Throughout this manual the following conventions are used for SCPI command syntax for remote interface programming e Square brackets indicate optional keywords or parameters e Braces enclose parameter choices within a command string e Triangle brackets lt gt enclose parameters for which you must substitute a value e A vertical bar separates multiple parameter choices Rules for Using a Channel List Many of the SCPI commands for the HP 34970A include a scan_list or ch_list parameter which allow you to specify one or more channels The channel number has the form see wheres is the
144. Commands see page 214 for more information CONFigure FREQuency lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe FREQuency VOLTage RANGe lt range gt MIN MAX lt ch_list gt FREQuency VOLTage RANGe lt ch_list gt MIN MAX FREQuency VOLTage RANGe AUTO OFF ON lt ch_list gt FREQuency VOLTage RANGe AUTO lt ch_list gt SENSe FREQuency APERture 0 01 0 1 1 MIN MAX lt ch_list gt FREQuency APERture lt ch_list gt MIN MAX SENSe FREQuency RANGe LOWer 3 20 200 MIN MAX lt ch_list gt FREQuency RANGe LOWer lt ch_list gt MIN MAX CONFigure PERiod lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe PERiod VOLTage RANGe lt range gt MIN MAX lt ch_list gt PERiod VOLTage RANGe lt ch_list gt MIN MAX PERiod VOLTage RANGe AUTO OFF ON lt ch_list gt PERiod VOLTage RANGe AUTO lt ch_list gt SENSe PERiod APERture 0 01 0 1 1 MIN MAX lt ch_list gt PERiod APERture lt ch_list gt MIN MAX B This command redefines the scan list when executed Default parameters are shown in bold 191 Chapter 5 SCPI Com Remote Interface Reference mand Summary Mx B Sc
145. Decimal or time portion of the number Dim dateNumber As Date Integer or date portion of the number Cells 1 1 ClearContents Cells 1 1 TimeString Range al TextToColumns Destination Range al comma True dateNumber DateSerial Cells 1 1 Cells 1 2 Cells 1 3 timeNumber TimeSerial Cells 1 4 Cells 1 5 Cells 1l 6 ConvertTime dateNumber timeNumber End Function Sub GetErrors Call this routine to check for instrument errors The HP IB address variable VISAaddr must be set Dim DataString As String OpenPort SendSCPI SYSTEM ERROR Read one error from the error queue Delay 0 1 DataString GetSCPI MsgBox DataString ClosePort End Sub 327 Chapter 7 Application Programs Example Programs for C and C Example Programs for C and C The following C programming examples show you how to send and receive formatted I O For more information on non formatted I O refer to the HP VISA User s Guide The examples in this section show you how to use the SCPI commands for the instrument with the VISA functionality and does not include error trapping Error trapping however is good programming practice and is recommended for your application For more information on error trapping refer to the HP VISA User s Guide The example programs are written in Microsoft Visual C Version 1 52 using project type QuickWin application and using the large memory model
146. HP 34901A and HP 34902A multiplexers have an additional relay called a bank switch or tree switch which helps reduce channel to channel noise Caaj The multiplexer channels are divided into two banks The bank switch isolates one bank of channels from the other effectively removing any parallel adjacent capacitance from the isolated bank During a scan the instrument automatically controls the bank switches B Bank Switch Cadi j s N ens Bank 1 Channel pO oN Source Switch Source Bank Switch L V 3 DNS a t V J Cadi ae vax Ne gt Bank 2 Channel Source ae Switch DMM ource NN A If you are not using all of the channels on the multiplexer divide the input signals equally between Bank 1 and Bank 2 For example if you are multiplexing eight channels using the 16 channel multiplexer use four channels in the lower bank and four channels in the upper bank For even better noise immunity leave one unused grounded channel between each input channel Module Bank 1 Bank 2 HP 34901A Channels 1 through 10 Channels 11 through 20 HP 34902A Channels 1 through 8 Channels 9 through 16 HP 34908A Channels 1 through 20 Channels 21 through 40 383 Chapter 8 Tutorial Actuators and General Purpose Switching Actuators and General Purpose Switching The HP 34903A Actuator provides 20 independent isolated SPDT single pole double throw or Form C switches This modu
147. HP 34970A makes measurements and discusses the most common sources of error related to these measurements The Internal DMM The internal DMM provides a universal input front end for measuring a variety of transducer types without the need for additional external signal conditioning The internal DMM includes signal conditioning amplification or attenuation and a high resolution up to 22 bits analog to digital converter A simplified diagram of the internal DMM is shown below For complete details on the operation of the internal DMM refer to Measurement Input on page 60 Pr aa F To peu nalog f nalog to A7 Earth Input o o i Amp Digital j Booed 4 Referenced Signal g Converter Section a Optical Isolators A The internal DMM can directly make the following types of measurements Each of these measurements is described in the following sections of this chapter e Temperature thermocouple RTD and thermistor e Voltage dc and ac up to 300V e Resistance 2 wire and 4 wire up to 100 MQ e Current dc and ac up to 1A e Frequency and Period up to 300 kHz 343 Chapter 8 Tutorial Measurement Fundamentals Rejecting Power Line Noise Voltages A desirable characteristic of an integrating analog to digital A D converter is its ability to reject spurious signals Integrating techniques reject power line related noise pr
148. IMIT UPPER 5 103 n taAcqu CALC LIMIT UPPER STATE ON 103 n taAcqu OUTPUT ALARM1 SOURCE 103 n taAcqu INIT OPC n the instrument to complete its operations so waste time and stay in the program in case there is an SRQ Continued on next page 330 Chapter 7 Application Programs Example Programs for C and C do Stay in loop until the srqFlag goes negative index 1 for count 0 count lt 45 count t index 0 prante 2 printf srq flag d n srqFlag while srqFlag gt 0 A negative srgqFlag indicates scan is done The instrument is done so close the SRQ handler viDisableEvent DataAcqu VI_EVENT_SERVICE_REQ VI_HNDLR viUninstallHandler DataAcqu VI_LEVENT_SERVICE_REQ SRQ_handler ViAddr 10 viPrintf DataAcqu FETCH n Get all the readings viScanf DataAcqu 101f amp volt Put readings into an array for index 0 index lt 10 index Print the readings printf reading d 1f n index 1 volt index viClose DataAcqu Close the communication port viClose defaultRM This function will be called when the instrument interrupts the controller with an SRQ for alarm and or Operation Complete ViStatus _VI_FUNCH SRQ_handler ViSession DataAcqu ViEventType eventType ViEvent context ViAddr userHdlr ViUInt16 statusByte viReadSTB DataAcqu amp statusByte Read statu
149. ITE Vout H gt 2 4V lout 1 mA L a faa Vout H Max lt 42V with external open drain pull up L 3a linsa con Stl Totalizer Pa es azo BO Maximum Count 67 108 863 27 1 Totalize Input 100 KHz max Signal Level 1 Vp p min 42 Vpk max DAC Output 12V non isolated lout 10 mA max per DAC 40 mA max per mainframe nike LOS99 2067 O 175 Chapter 4 Features and Functions HP 34908A 40 Channel Single Ended Multiplexer HP 34908A 40 Channel Single Ended Multiplexer The module is divided into two banks of 20 channels each All of the 40 channels switch HI only with a common LO for the module The module has a built in isothermal block to minimize errors due to thermal gradients when measuring thermocouples Channel Switches a H ot OA TO H 20 4 Com Backplane 2 Switch 4 AL Com Internal o o Bank Switch V DMM Input o o 99 o C 93o V oo Du 21 xO PD Reference A oo QH 40 Junction lt pT Sensor T NOTES e Refer to the diagrams on page 20 to connect wiring to the module e Only one channel can be closed at a time closing one channel will open the previously closed channel e This module cannot be used to directly measure current or any 4 wire measurements e When connecting thermocouples to the screw terminals on this module be sure to provide electrical isolation between thermocouples 20 AWG Typical
150. If more than 10 errors have occurred the last error stored in the queue the most recent error is replaced with Error queue overflow No additional errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the instrument responds with No error The error queue is cleared by the cLs clear status command or when power is cycled The errors are also cleared when you read the queue The error queue is not cleared by a Factory Reset RST command or an Instrument Preset SySTem PRESet command Front Panel Operation ERRORS If the ERROR annundiator is on press to view the errors Use the knob to scroll through the error numbers Press L to view the text of the error message Press D again to increase the scrolling speed the final key press cancels the scroll All errors are cleared when you exit the menu Remote Interface Operation SYSTem ERRor Read and clear one error from the queue Errors have the following format the error string may contain up to 80 characters 113 Undefined header 142 Chapter 4 Features and Functions System Related Operations Self Test A power on self test occurs automatically when you turn on the instrument This limited test assures you that the instrument and all installed plug in modules are operational This self test does not perform the extensive set of tests that are included as part of the complete s
151. If the ERROR annunciator is on press to view the errors Use the knob to scroll through the error numbers Press L to view the text of the error message Press D again to increase the scrolling speed the final key press cancels the scroll All errors are cleared when you exit the menu e Remote Interface Operation SYSTem ERRor Read and clear one error from the queue Errors have the following format the error string may contain up to 80 characters 113 Undefined header 304 101 102 103 105 108 109 112 113 Chapter 6 Error Messages Execution Errors Execution Errors Invalid character An invalid character was found in the command string You may have used an invalid character such as or in the command header or within a parameter Example CONF VOLT DC 101 Syntax error Invalid syntax was found in the command string You may have inserted a blank space before or after a colon in the command header or before a comma Or you may have omitted the character in the channel list syntax Examples ROUT CHAN DELAY 1 or CONF VOLT DC 101 Invalid separator An invalid separator was found in the command string You may have used a comma instead of a colon semicolon or blank space or you may have used a blank space instead of a comma Examples TRIG COUNT 1 or CONF FREQ 1000 0 1 GET not allowed A Group Execute Trigger GET is not allowe
152. In addition to setting the gain M and offset B values you can also specify a custom measurement label for your scaled readings RPM PSI etc 1 Configure the channel You must configure the channel function transducer type etc before applying any scaling values If you change the measurement configuration scaling is turned off on that channel and the gain and offset values are reset M 1 and B 0 2 Set the gain and offset values The scaling values are stored in non volatile memory for the specified channels A Factory Reset turns off scaling and clears the scaling values on all channels An Instrument Preset or Card Reset does not clear the scaling values and does not turn off scaling 1 000 000 Set Gain 40 000 000 voc Set Offset 3 Select the custom label You can specify an optional three character label for your scaled readings RPM PSI etc The default label is the standard engineering unit for the selected function VDC OHM etc LABEL AS LBS 4 Run the scan and store the scaled readings in memory 39 Measure Alarm Alarm Chapter 2 Front Panel Overview To Configure Alarm Limits To Configure Alarm Limits The instrument has four alarms which you can configure to alert you when a reading exceeds specified limits on a channel during a scan You can assign a high limit a low limit or both to any configured channel in the scan list You can assign multiple channels to
153. LTage DC RANGe lt range gt MINimum MAXimum lt ch_list gt Discrete Parameters Discrete parameters are used to program settings that havea limited number of values like BUS IMMediate EXTernal They havea short form and a long form just like command keywords You can mix upper and lower case letters Query responses will always return the short form in all upper case letters The following command uses discrete parameters UNIT TEMPerature C F K lt ch_list gt Boolean Parameters Boolean parameters represent a single binary condition that is either true or false For a false condition the instrument will accept OFF or 0 F or a true condition the instrument will accept ON or 1 When you query a boolean setting the instrument will always return 0 or 1 The following command uses a boolean parameter INPut IMPedance AUTO OFF ON lt ch_list gt 300 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language String Parameters String parameters can contain virtually any set of ASCII characters A string must begin and end with matching quotes either with a single quote or with a double quote You can include the quote delimiter as part of the string by typing it twice without any characters in between The following command uses a string parameter DISPlay TEXT lt quoted_string gt Channel List Parameters Channel list parameters specify on
154. Maximum Input Voltage 300 V CAT I Maximum Input Current 1 A fo fe Maximum Switching Power 50 W 6mm Z WARNING To prevent electrical shock use only wire that is rated for the highest voltage applied to any channel Before removing a module cover turn off all power to external devices connected to the module 176 Chapter 4 Features and Functions HP 34908A 40 Channel Single Ended Multiplexer J pe F O WIRING LOG Slot Number J 100 0200 0300 Function Comments MR ma SLs LJ ws S ko L Tee S BF g 92 8 m pei O pss S 8 h7 L o JIO Spey Sr Slt Li BS mjo OPA g 0 4s O EF i _ S 3 0 p27 Ld amp 2 re SS BI S mjo SSO olog S po 2 6 pss 2 Op amp LK 8 pepe i C B SF Z 7 O be m S Ot Sk e 5 See i lt lt ke 6 Sba w O b 1 D S 22 S 7 SP De i Ol loi o I I 177 Remote Interface Reference Remote I nterface Reference e SCPI Command Summary star
155. OTalize TYPE RRESet command or the Advanced menu for the totalizer If you install a module while a scan is running the instrument will cycle power and resume scanning If you remove a module while a scan is running the instrument will cycle power and resume scanning even if the removed module was part of the scan list You can use either the internal DMM or an external DMM to make measurements of your configured channels However the instrument allows only one scan list at a time you cannot scan some channels using the internal DMM and others using an external DMM Readings are stored in HP 34970A memory only when the internal DMM is used If the internal DMM is installed and enabled the instrument will automatically use it for scanning For externally controlled scans you must either remove the internal DMM from the HP 34970A or disable it see Internal DMM Disable on page 145 76 Chapter 4 Features and Functions Scanning Power Failure e When shipped from the factory the instrument is configured to automatically recall the power down state when power is restored In this configuration the instrument will automatically recall the instrument state at power down and resume a scan in progress If you do not want the power down state to be recalled when power is restored send the MEMory STATe RECall AUTO OFF command also see the Utility menu a Factory Reset RST command is then issued when power
156. Oe OY OY ev Oe OY OY nev ae Yn ne eae nna To change the HP IB address modify the variable VISAaddr below VISAaddr 9 OpenPort Open communications on HP IB SendSCPI RST Issue a Factory Reset to the instrument OVE TPP OY Wee Pre OY nny We Pye OY ve WY We Pe OY WY We PY oe OY vy ve PY We OY OY Oe OY Oe OY OY Oe OOOO Oe van ne vay neon nn SET UP Modify this section to select the scan interval the scan count and channel delay These are variables that are used to set the scan parameters ScanInterval 10 Delay in secs between scans numberScans 3 Number of scan sweeps to measure channelDelay 0 1 Delay in secs between relay closure and measurement To delete channels from the scan list modify the scan list string variable scanList below To add channels to the scan list modify scanList and then configure the channel using the CONFigure command scanList is the list of channels in the scan list note that this does not have to include all configured channels in the instrument scanList 101 102 110 112 SendSCPI CONF TEMP TC T 101 Configure channel 101 for temperature SendSCPI CONF TEMP TC K 102 Configure channel 102 for temperature SendSCPI CONF TEMP THER 5000 103 Configure channel 103 for temperature 7 SendSCPI CONF VOLT DC 110 111 112 Configure three channels for dc volts SendSCPI ROUTE SCAN a
157. P 34906A 173 cable tie wiring 20 cabling attenuation 336 capacitance 336 coaxial 55 dielectric withstand voltage 335 errors 339 flat ribbon 55 nominal impedance 335 resistance 336 RS 232 17 51 273 shielded coaxial 338 shielding 338 specifications 335 twisted pair 55 338 types 55 wire gauge size 336 calculation error thermocouple 353 CALC AVER command 92 CALC AVER AVER command 234 CALC AVER CLEar command 234 CALC AVER COUNt command 234 CALC AVER MAX TIME command 233 CALC AVER MAX command 233 CALC AVER MIN TIME command 233 CALC AVER MIN command 233 CALC AVER PTPeak command 234 CALC COMP DATA command 253 CALC COMP MASK command 254 CALC COMP STATe command 254 CALC COMP TYPE command 253 CALC LIM LOW command 251 CALC LIM LOW STATe command 251 CALC LIM UPP command 250 CALC LIM UPP STATe command 250 CALC SCALe GAIN command 245 CALC SCALe OFFS command 245 CALC SCALe OFFS NULL command 246 CALC SCALe STATe command 246 CALC SCALe UNIT command 245 calendar factory setting 145 setting 22 145 calibration certificate 17 calibration overview 155 read count 159 security code 155 text message 158 to secure 157 to unsecure 156 CAL COUNt command 292 CAL SECure CODE command 292 CAL SECure STATe command 293 CAL STRing command 293 CAL VALue command 293 CAL command 292 capacitance cable 336 capacitive coupling 338 381 Card Reset key 2
158. PI version Returns a string in the form YYYY V where YYYY represents the year of the version and V represents a version number for that year e g 1994 0 TST Perform a complete self test of the instrument Returns 0 if the self test is successful or 1 if the test fails 268 Chapter 5 Remote Interface Reference Interface Configuration Commands nterface Configuration Commands See also Remote Interface Configuration in chapter 4 starting on page 150 SYSTem INTerface GPIB RS232 Select the remote interface Only one interface can be enabled at a time The HP IB interface is selected when the instrument is shipped from the factory SYSTem LOCal Place the instrument in the local mode for RS 232 operation All keys on the front panel are fully functional while in the local mode SYSTem REMote Place the instrument in the remote mode for RS 232 operation All keys on the front panel except are disabled while in the remote mode SYSTem RWLock Place the instrument in the remote mode for RS 232 operation This command is the same as the SySTem REMote command except that all keys on the front panel are disabled including the key lt Ctr1 C gt Clear the operation in progress over the RS 232 interface and discard any pending output data This is equivalent to the IEEE 488 Device Clear action over the HP IB interface 269 Chapter 5 Remote Interface Referenc
159. POL query returns the alarm output configuration Returns NEG or POS Note that changing the slope of the output lines may cause the lines to change state OUTPut ALARm 1 2 3 4 CLEar ALARm CLEar ALL Clear the specified alarm output lines Send CLEAR ALL to clear all four alarm output lines You can manually clear the output lines at any time even during a scan and the alarm data in memory is not cleared however data is cleared when you initiate a new scan The alarm outputs are also cleared when you initiate a new scan 252 Chapter 5 Remote Interface Reference Alarm System Overview Digital I O Alarm Commands See also Using Alarms With the Multifunction Module in chapter 4 starting on page 130 CALCulate COMPare TYPE EQUal NEQual lt ch_list gt COMPare TYPE lt ch_list gt Select the comparison mode for alarms on the specified DIO channels Select EQUa1 to generate an alarm when the data read from the port is equal to CALC COMP DATA after being masked by CALC COMP MASK Select NEQual not equal to generate an alarm when the data read from the port is not equal to CALC COMP DATA after being masked by CALC COMP MASK The default is NE Qual The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot The TYPE query returns the comparison mode setting on the specified DIO channels Returns EQU or
160. Resistance 100 mV 1 V 10 V ranges 100 V 300 V ranges Input Bias Current Input Protection Continuously Integrating Multi slope Ill A D Converter 0 0002 of reading 0 0001 of range Selectable 10 MQ or gt 10 GQ 10 MQ 1 lt 30 pA at 25 C 300 V on all ranges Resistance Measurement Method Offset Compensation Max Lead Resistance Input Protection Selectable 4 wire or 2 wire Ohms Current source reference to LO input Selectable on 1009 1 KQ 10 kQ ranges 10 of range per lead for 100Q and 1 kQ ranges 1 kQ on all other ranges 300 V on all ranges DC Current Shunt Resistance Input Protection 5Q for 10 mA 100 mA 0 19 for 1A 1 5A 250 V fuse on HP 34901A module Thermocouple Conversion Reference Junction Type Open T C Check ITS 90 software compensation Internal Fixed or External Selectable per channel Open gt 5 kQ Additional Function Digits 6 Readings s Noise Error DCV DCI and 61 2 0 6 0 5 0 of range Resistance 61 6 5 0 of range 5 2 60 50 0 001 of range 51 300 0 001 of range 7 41 600 0 01 of range l Single Channel Measurement Rates l Function Resolution Readings s DCV 2 Wire Ohms 61 10 PLC 6 5 51 1 PLC 57 47 41 2 0 02 PLC 600 Thermocouple 0 1 C 1 PLC 57 47 0 02 PLC 220 RTD Thermistor 0 01 C 10 PLC 6 5 0 1 C 1 PLC 57 47 1 C 0 02 PLC 220 Autozero OFF Operation Following instrument
161. Set the resolution to 6 digits e Select the slow ac filter 3 Hz to 300 kHz Frequency and Period Measurements e Set the resolution to 6 digits 419 Index If you have questions relating to the operation of the HP 34970A call 1 800 452 4844 in the United States or contact your nearest Hewlett Packard Sales Office Warnings HP 34901A 165 HP 34902A 167 HP 34903A 169 HP 34904A 171 HP 34908A 176 ly digit 100 416 4W annunciator 4 502 RF switching 390 75Q RF switching 390 CLS command 291 ESE command 288 ESR command 288 IDN command 265 OPC command 279 291 OPC command 279 PSC command 291 RCL command 261 RST command 160 267 295 SAV command 261 SRE command 286 STB command 278 286 TRG command 82 230 TST command 268 295 WAI command 295 A ABORt command 79 230 aborting a scan 78 79 absolute time 87 ac bandwidth ac current 116 ac voltage 114 vs channel delays 89 ac current ac filter 116 361 connections 21 low frequency filter 116 361 measurement ranges 21 116 settling time 116 361 ac filter definition 114 116 361 vs channel delays 89 ac measurement errors 341 ac settling time 114 116 ac voltage measurements ac filter 114 361 connections 21 loading errors 364 low frequency filter 114 361 ranges 21 113 settling time 114 361 signal conditioning 359 true RMS measurements 360 accuracy 417 accuracy sp
162. TO lt ch_list gt Disable or enable the automatic input resistance mode for dc voltage measurements on the specified channels With AUTO OFF default the input resistance is fixed at 10 MQ for all ranges With AUTO ON the input resistance is set to gt 10 Ga for the 100 mV 1 V and 10 V ranges The AUTO query returns the input resistance setting on the specified channels Returns 0 OFF or 1 ON SENSe VOLTage AC BANDwidth 3 20 200 MIN MAX lt ch_list gt VOLTage AC BANDwidth lt ch_list gt MIN MAX Specify the lowest frequency expected in the input signal for ac voltage measurements on the specified channels The instrument selects the slow medium default or fast ac filter based on the frequency you specify MIN 3 Hz MAX 200 Hz The BAND query returns the ac filter setting on the specified channels Returns 3 20 or 200 SENSe ZERO AUTO OFF ONCE ON lt ch_list gt ZERO AUTO lt ch_list gt Disable or enable default the autozero mode The OF F and ONCE parameters have a similar effect Autozero OFF does not issue a new zero measurement until the next time the instrument goes to the wait for trigger state Autozero ONCE issues an immediate zero measurement The AUTO query the autozero mode Returns 0 OFF or ONCE or 1 ON 223 Chapter 5 Remote Interface Reference Resistance Configuration Commands
163. This is a read only register Once a bit is set it remains set until cleared by the STATus OPER EVENt command or CLS clear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus OPERation ENABle lt enable_value gt STATus OPERation ENABle Enable bits in the enable register in this register group The selected bits are then reported to the Status Byte A cLS clear status will not clear the enable register but it does clear all bits in the event register A STATus PRESet Clears all bits in the enable register To enable bits in the enable register you must write a dedmal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The ENABle query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the STATus OPER ENABle command 290 Chapter 5 Remote Interface Reference Status System Commands DATA POINts EVENt THReshold lt num_rdgs gt DATA POINts EVENt THReshold Set a bit in the event register when the specified number of readings have been stored in reading memory during a scan You can set the memory threshold to any value between 1 reading and 50 000 readings The default is 1 reading When the specified number of readings have been stored in memory the Memory Threshold bit bit 9 is set toa
164. To Output a DC Voltage 45 To Configure the Remote Interface 46 To Store the Instrument State 48 Chapter 3 System Overview Data Acquisition System Overview 50 Signal Routing and Switching 57 Measurement Input 60 Control Output 67 11 Q e gt r 9 amh N c cab c O 8 Contents Chapter 4 Features and Functions SCPI Language Conventions 73 Scanning 74 Single Channel Monitoring 93 Scanning With External Instruments 95 General Measurement Configuration 98 Temperature Measurement Configuration 106 Voltage Measurement Configuration 113 Resistance Measurement Configuration 115 Current Measurement Configuration 116 Frequency Measurement Configuration 118 Mx B Scaling 119 Alarm Limits 122 Digital Input Operations 133 Totalizer Operations 135 Digital Output Operations 138 DAC Output Operations 139 System Related Operations 140 Remote Interface Configuration 150 Calibration Overview 155 Factory Reset State 160 Instrument Preset State 161 Multiplexer Module Default Settings 162 Module Overview 163 HP 34901A 20 Channel Multiplexer 164 HP 34902A 16 Channel Multiplexer 166 HP 34903A 20 Channel Actuator 168 HP 34904A 4x8 Matrix Switch 170 HP 34905A 6A Dual 4 Channel RF Multiplexers 172 HP 34907A Multifunction Module 174 HP 34908A 40 Channel Single Ended Multiplexer 176 12 Contents Chapter 5 Remote Interface Reference SCPI Command Summary 181 Simplified Prog
165. UNIT o PK PK EMER ER EKER EXER ERE K Ee GB 82 i co co CONFIG ADRS RMT ERROR EXT ONCE MEM LAST MIN WAX AVG SHIFT H ett 234 SCAN Scan is in progress or enabled Press and hold again to turn off MON Monitor mode is enabled Press again to turn off VIEW Scanned readings alarms errors or relay cycles are being viewed CONFIG Channel configuration is in progress on displayed channel x Measurement is in progress ADRS Instrument is addressed to listen or talk over the remote interface RMT Instrument is in remote mode remote interface ERROR Hardware or remote interface errors are detected Press to read errors EXT Instrument is configured for an external scan interval ONCE Scan Once mode is enabled Press to initiate and hold key to disable MEM Reading memory overflow new readings will overwrite the oldest readings LAST Viewed data is the ast reading stored during most recent scan MIN Viewed data is the minimum reading stored during most recent scan MAX Viewed data is the maximum reading stored during most recent scan SHIFT has been pressed Press again to turn off 4w 4 wire function is in use on displayed channel oc Offset compensation is enabled on displayed channel a Alarms are enabled on displayed channel a Mx B scaling is enabled on displayed channel is HI or LO alarm condition has occurred on indicated alarms To review the display annunciators hold down the key as you turn on the
166. UTe CHANnel FWIRe OFF ON lt ch_list gt CHANnel FWIRe lt ch_list gt This command is valid only when the internal DMM is disabled or removed from the HP 34970A Configure the list of channels for 4 wire external scanning without the internal DMM When enabled the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections For example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel Note that the ROUT CLOSe ROUT CLOSe EXCL and ROUT OPEN commands ignore the current ROUT CHAN FWIRe setting if no channels arein the scan list The FWIR query returns a 0 4 wire pairing disabled or 1 4 wire pairing enabled for each channel in the scan list INSTrument DMM OFF ON DMM Disable or enable the internal DMM When you change the state of the internal DMM the instrument issues a F actory Reset RST command The DMM query returns the state of the internal DMM Returns 0 disabled or 1 enabled INSTrument DMM INSTalled Query the instrument to determine if the internal DMM is installed Returns 0 not installed or 1 installed 243 Chapter 5 Remote Interface Reference Mx B Scaling Overview Mx B Sc
167. Unit Model Number HP 34970A Product Options All Options conforms to the following Product Specifications Safety IEC 1010 1 1990 Incl Amend 1 1992 EN61010 1993 CSA C22 2 1010 1 1992 UL 1244 CISPR 11 1990 EN55011 1991 Group 1 Class A IEC 801 2 1991 EN50082 1 1992 4 kV CD 8 kV AD IEC 801 3 1984 EN50082 1 1992 3 V m IEC 801 4 1988 EN50082 1 1992 1 kV Power Lines 0 5 kV Signal Lines Supplementary Information The product herewith complies with the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 336 EEC and carries the CE marking accordingly Loveland Colorado June 1 1997 pal Jim White QA Manager European Contact Your local Hewlett Packard Sales and Service Office or Hewlett Packard GmbH Department ZQ Standards Europe Herrenberger Stra e 130 D 71034 B blingen FAX 49 7031 143143 Copyright 1997 Hewlett Packard Company All Rights Reserved Printing History Edition 1 June 1997 Edition 2 October 1997 New editions are complete revisions of the manual Update packages which are issued between editions may contain additional in formation and replacement pages which you merge into the manual The dates on this page change only when a new edition is published Certification Hewlett Packard HP certifies that this product met its published specifications at the time of shipment HP further certifies that its calibra
168. Wire Ohms 2 or 4 Wire Ohms Transducer Sensitivity 6 wV C to 60 uV C Ro x 0 004 C 400 2 C Probe Accuracy 0 5 C to 5 C 0 01 C to0 1 C 0 1 Cto1 C Cost U S Dollars 1 foot 20 to 100 each 10 to 100 each Durability Rugged Fragile Fragile 345 Chapter 8 Tutorial Measurement Fundamentals RTD Measurements An RTD is constructed of a metal typically platinum that changes resistance with a change in temperature in a precisely known way The internal DMM measures the resistance of the RTD and then calculates the equivalent temperature An RTD has the highest stability of the temperature transducers The output from an RTD is also very linear This makes an RTD a good choice for high accuracy long term measurements The HP 34970A supports RTDs with a 0 00385 DIN IEC 751 and a 0 00391 PT100 is a special label that is sometimes used to refer to an RTD with a 0 00385 and R 1002 The resistance of an RTD is nominal at 0 C and is referred to as Ro The HP 34970A can measure RTDs with Ro values from 499 to 2 1 KQ You can measure RTDs using a 2 wire or 4 wire measurement method The 4 wire method with offset compensation provides the most accurate way to measure small resistances Connection lead resistance is automatically removed using the 4 wire method Thermistor Measurements A thermistor is constructed of materials that non linearly changes resistance with changes in temperat
169. You can specify a custom label with up to three characters You can use letters A Z numbers 0 9 an underscore _ or the character which displays a degree symbol on the front panel displayed as a blank space in an output string from the remote interface The first character must be a letter or the character the character is allowed only as the leftmost character in the label The remaining two characters can be letters numbers or an underscore The following command shows how to add a custom label CALC SCALE UNIT PSI 101 Note Ifyou set the measurement label to C F or K note that this has no effect on the temperature units set using the UNIT TEMP command 245 Chapter 5 Remote Interface Reference Mx B Scaling Overview CALCulate SCALe OFFSet NULL lt ch_list gt Make an immediate null measurement on the specified channels and store it as the offset B for subsequent measurements This allows you to adjust for voltage or resistive offsets through your wiring to the point of the measurement CALCulate SCALe STATe OFF ON lt ch_list gt SCALe STATe lt ch_list gt Disable or enable scaling on the specified channels The STATe query returns the state of the scaling function on the specified channels Returns 0 OFF or 1 ON 246 Chapter 5 Remote Interface Reference Alarm System Overview Alarm System Overview
170. a is not overwritten The output buffer is cleared when power has been off or after a bus Device Clear Query UNTERMINATED The instrument was addressed to talk i e send data over the interface but a command has not been received which sends data to the output buffer For example you may have executed a CONFigure command which does not generate data and then attempted to read data from the remote interface Query DEADLOCKED A command was received which generates too much data to fit in the output buffer and the input buffer is also full Command execution continues but all data is lost Query UNTERMINATED after indefinite response The IDN command must be the last query command within a command string The IDN command returns an indefinite length string which cannot be combined with any other query command Example IDN STB 308 111 112 113 201 202 203 204 Chapter 6 Error Messages Instrument Errors Instrument Errors Channel list slot number out of range The specified slot number is invalid The channel number has the form sec where s is the slot number 100 200 or 300 and ce is the channel number Example CONF VOLT DC 404 Channel list channel number out of range The specified channel number is invalid for the module in the selected slot The channel number has the form sec where s is the slot number 100 200 or 300 and ce is the channel number Example ROUT CLOSE
171. a security code to prevent accidental or unauthorized calibrations of the instrument When you first receive your instrument it is secured Before you can calibrate the instrument you must unsecure it by entering the correct security code If you forget your security code you can disable the security feature by adding a jumper inside the instrument See the HP 34970A Service Guide for more information e The security code is set to HP034970 when the instrument is shipped from the factory The security code is stored in non volatile memory on the mainframe and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e The security code may contain up to 12 alphanumeric characters The first character must be a letter but the remaining characters can be letters numbers or an underscore _ You do not have to use all 12 characters but the first character must always bea letter 155 Chapter 4 Features and Functions Calibration Overview To Unsecure for Calibration You can unsecure the instrument either from the front panel or over the remote interface The instrument is secured when shipped from the factory and the security code is set to HP034970 e Once you enter a security code that code must be used for both front panel and remote operation For example if you secure the instrument from the front panel you must use that
172. able on page 203 SENSe VOLTage DC RESolution lt ch_list gt MIN MAX RESistance RESolution lt ch_list gt MIN MAX FRESistance RESolution lt ch_list gt MIN MAX CURRent DC RESolution lt ch_list gt MIN MAX Query the resolution setting on the specified channels Returns a number in the form 3 00000000E 05 216 Chapter 5 Remote Interface Reference Setting the Function Range and Resolution SENSe VOLTage DC APERture lt time gt MIN MAX lt ch_list gt RESistance APERture lt time gt MIN MAX lt ch_list gt FRESistance APERture lt time gt MIN MAX lt ch_list gt CURRent DC APERture lt time gt MIN MAX lt ch_list gt Select the aperture time for the function selected on the specified channels MIN selects the smallest value accepted for this parameter which gives the most resolution MAX selects the largest value accepted for this parameter which gives the least resolution For more information on aperture time refer to Custom A D Integration Time in chapter 4 starting on page 103 SENSe VOLTage DC APERture lt ch_list gt MIN MAX RESistance APERture lt ch_list gt MIN MAX FRESistance APERture lt ch_list gt MIN MAX CURRent DC APERture lt ch_list gt MIN MAX Query the aperture time setting on the specified channels Returns a number in the form 1 66666
173. abling 145 reading relay count 147 internal reference thermocouple 107 internal timer scan interval 80 interval scan default value 81 resolution 81 setting from front panel 81 setting from remote 81 settings 81 Interval key 35 81 97 interval scan to scan 38 80 isothermal block 107 350 ITS 90 conversions 107 345 J jumper Totalize Threshold 135 175 junction temperature 347 K Kelvins setting units 106 L labels Mx B scaling 39 120 stored states 48 LAN to HP IB Gateway 51 language SCPI summary 181 200 language SCPI syntax conventions 73 181 command syntax 299 version query 149 LAST annunciator 4 latch mode alarm output lines 128 limits alarms annunciators 124 clearing alarm outputs 129 configuring 40 default settings 41 124 interaction with Mx B 40 123 output connector location 5 output connector pinout 128 output latch mode 128 output slope polarity 129 output track mode 128 scan on alarm 84 setting limits 40 with readings 87 426 Index line voltage factory setting 27 fuse 27 selection 27 selector module 5 28 loading errors ac voltage 364 dc input resistance 357 input bias current 358 lock link kit rack mounting 31 long form SCPI commands 297 low frequency limit ac current 116 frequency 118 M M Mx B scaling gain 119 magnetic field errors 340 mainframe firmware revision 146 installing a module 2
174. address for any instrument on the interface bus Hewlett Packard HP IB interface cards generally use address 21 e Front Panel Operation ADDRESS 09 150 Chapter 4 Features and Functions Remote Interface Configuration Remote Interface Selection The instrument is shipped with both an HP IB IEE E 488 interface and an RS 232 interface Only one interface can be enabled at a time The HP IB interface is selected when the instrument is shipped from the factory e The interface selection is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet Command e If you select the HP IB interface you must select a unique address for the instrument The HP IB address is displayed on the front panel when you turn on the instrument e Ifyou select the RS 232 interface you must also set the baud rate parity and flow control mode for the instrument RS 232 is displayed on the front panel when you turn on the instrument e Front Panel Operation HPIB 488 RS 232 e Remote Interface Operation SYSTem INTerface GPIB RS232 151 Chapter 4 Features and Functions Remote Interface Configuration Baud Rate Selection RS 232 You can select one of eight baud rates for RS 232 operation The rate is set to 57 600 baud when the instrument is shipped from the factory You can set the baud rate from the f
175. age 407 Errorpandwidth Estimated bandwidth error as shown below C F 2 x F Errofpandwidth ar XBW Where C F Signal crest factor see the table on page 360 F Fundamental input signal frequency BW DMM s 3 dB bandwidth 1 MHz for the HP 34970A 362 Chapter 8 Tutorial Measurement Fundamentals Example Calculating Measurement Error Calculate the approximate measurement error for a pulse train input with a crest factor of 3 and a fundamental frequency of 20 kHz The internal DMM is set to the 1 V range For this example use the 90 day accuracy specifications of 0 05 of reading 0 04 of range as shown in chapter 9 on page 406 Errorsine 0 05 0 04 0 09 Errorcrest factor 0 15 3 x 20000 Errorbandwidth 4 x 3 44159 x 1000000 100 1 4 Total Error 0 09 0 15 1 4 1 6 363 Chapter 8 Tutorial Measurement Fundamentals AC Loading Errors In the ac voltage function the input of the internal DMM appears as a 1 MQ resistance in parallel with 150 pF of capacitance The cabling that you use to connect signals to the instrument will also add additional capacitance and loading The table below shows the approximate input resistance at various frequencies Input Frequency Input Resistance 100 Hz 700 kQ 1 kHz 600 ka 10 kHz 100 ka 100 kHz 10 ka For low frequencies 100 x R Error a My s Additional error for high
176. al Const VI_SUCCESS 0 Global Variables Global videfaultRM As Long Resource manager id for VISA GPIB Global vi As Long Stores the session for VISA Dim errorStatus As Long VTL error code Global VISAaddr As String VTP UY We re Pre OY YOY We Pee OY OY We Ye OY ny We Oe OY OY We OY We OY OY We OY Oe OY OY Oe OO OY OY Oe OY OO OY neva OY One ean none tno This routine requires the file VISA32 DLL which typically resides in the c windows system directory on your PC This routine uses the VIL Library to send commands to the instrument A description of these and additional VTL commands can be found in the HP VISA User s Guide part number E2090 90029 Public Sub SendSCPI SCPICmd As String This routine sends a SCPI command string to the HP IB port If the command is a query command contains a question mark you must read the response with getScpi Dim commandstr As String Command passed to instrument Dim actual As Long Number of characters sent returned Write the command to the instrument terminated by a line feed commandstr SCPICmd amp Chr 10 errorStatus viWrite vi ByVal commandstr Len commandstr actual End Sub Function getScpi As String Dim readbuf As String 2048 Buffer used for returned string Dim replyString As String Store the string returned Dim nulpos As Integer Location of any nul s in readbuf Dim actual As Long Number of characters sent
177. al DMM to make measurements of your configured channels However the instrument allows only one scan list at a time you cannot scan some channels using the internal DMM and others using an external DMM Readings are stored in HP 34970A memory only when the internal DMM is used e If theinternal DMM is installed and enabled the instrument will automatically use it for scanning For externally controlled scans you must either remove the internal DMM from the HP 34970A or disable it see Internal DMM Disable on page 145 Scan Interval You can configure the event or action that controls the onset of each sweep through the scan list a sweep is one pass through the scan list e You can set theinstrument s internal timer to automatically scan at a specific interval You can also program a time delay between channels in the scan list e You can manually control a scan by repeatedly pressing from the front panel e You can start a scan by sending a software command from the remote interface MEASure or INITiate command e You can start a scan when an external TTL trigger pulse is received e You can start a scan when an alarm event is logged on the channel being monitored 227 Chapter 5 Remote Interface Reference Scanning Overview Scanning Commands ROUTe SCAN lt scan_list gt SCAN Select the channels to be included in the scan list To start the scan use the INITiate or READ command To remove
178. al Multiplexing 390 Multifunction Module 392 Relay Life and Preventative Maintenance 399 Chapter 9 Specifications DC Resistance and Temperature Accuracy Specifications 404 DC Measurement and Operating Characteristics 405 AC Accuracy Specifications 406 AC Measurement and Operating Characteristics 407 Measurement Rates and System Characteristics 408 Module Specifications 409 HP BenchLink Data Logger Software Specifications 412 Product and Module Dimensions 413 To Calculate Total Measurement Error 414 Interpreting Internal DMM Specifications 416 Configuring for Highest Accuracy Measurements 419 Index 14 Quick Start Quick Start One of the first things you will want to do with your instrument is to become acquainted with the front panel We have written the exercises in this chapter to prepare the instrument for use and help you get familiar with some of its front panel operations The front panel has several groups of keys to select various functions and operations A few keys have a shifted function printed in blue below the key To perform a shifted function press CD the SHIFT annunciator will turn on Then press the key that has the desired label below it For example to select the Utility Menu press If you accidentally press CD just press it again to turn off the SHIFT annunciator This chapter is divided into the following sections e To Prepare the Instrument for Use on page 17 e Installin
179. al shock use only wire that is rated for the highest voltage applied to any channel Before removing a module cover turn off all power to external I devices connected to the module 165 Chapter 4 Features and Functions HP 34902A 16 Channel Multiplexer HP 34902A 16 Channe Multiplexer This module is divided into two banks of eight channels each All 16 channels switch both HI and LO inputs thus providing fully isolated inputs to the internal DMM or an external instrument When making 4 wire resistance measurements the instrument automatically pairs channel n with channel n 8 to provide the source and sense connections The module has a built in isothermal block to minimize errors due to thermal gradients when measuring thermocouples _ Backplane Switches Channel Switches Internal 2 H 01 DMM Input QL DH oL 08 DH 7 o Com Reference ps Q Junction lt 1 99 Sensor J oe n a Com 4W Sense SH a 09 Internal _H S DMM Input lt _L oL 16 4W Sense i NOTES e f any channels are configured to be part of the scan list you cannot close multiple channels closing one channel will open the previously closed channel e Current measurements on this module will require external shunt resistors 166 Chapter 4 Features and Functions HP 34902A 16 Channel Multiplexer
180. aling Commands see page 244 for more information CALCulate SCALe SCALe SCALe SCALe SCALe SCALe CALCulate CALCulate SCALe SCALe GAIN lt gain gt lt ch_list gt GAIN lt ch_list gt OFFSet lt offset gt lt ch_list gt OFFSet lt ch_list gt UNIT lt quoted_string gt lt ch_list gt UNIT lt ch_list gt SCALe OFFSet NULL lt ch_list gt STATe OFF ON lt ch_list gt STATe lt ch_list gt 192 Chapter 5 Remote Interface Reference SCPI Command Summary Alarm Limit Commands see page 247 for more information OUTPut ALARm 1 2 3 4 SOURce lt ch_list gt ALARm 1 2 3 4 SOURce CALCulate LIMit UPPer lt hi_limit gt lt ch_list gt LIMit UPPer lt ch_list gt LIMit UPPer S e OFF ON lt ch_list gt LIMit UPPer S e lt ch_list gt A A CALCulate LIMit LOWer lt lo_limit gt lt ch_list gt LIMit LOWer lt ch_list gt IMit LOWer STATe OFF ON lt ch_list gt IMit LOWer STATe lt ch_list gt SYSTem ALARm OUTPut ALARm MODE LATCh TRACk ALARm MODE ALARm SLOPe NEGative POSitive ALARm SLOPe OUTPut ALARm 1 2 3 4 CLEar ALARm CLEar ALL STATus ALARm CONDition ALARm ENABle lt enable_value gt ALARm ENAB1le ALARm
181. aling Overview See also Mx B Scaling in chapter 4 starting on page 119 The scaling function allows you to apply a gain and offset to all readings on a specified multiplexer channel during a scan In addition to setting the gain M and offset B values you can also specify a custom measurement label for your scaled readings RPM PSI etc You can apply scaling to any multiplexer channels and for any measurement function Scaling is not allowed with any of the digital channels on the multifunction module e Scaling is applied using the following equation Scaled Reading Gain x Measurement Offset e You must configure the channel function transducer type etc before applying any scaling values If you change the measurement configuration scaling is turned off on that channel and the gain and offset values are reset M 1 and B 0 Scaling is also turned off when you change the temperature probe type temperature units or disable the internal DMM e f you plan to use scaling on a channel which will also use alarms be sure to configure the scaling values first If you attempt to assign the alarm limits first the instrument will turn off alarms and clear the limit values when you enable scaling on that channel If you specify a custom measurement label with scaling it is automatically used when alarms are logged on that channel e f you redefine the scan list scaling is turned off on those channels but
182. als and within a stable environment Short term accuracy is usually specified for a 24 hour period and for a 1 C temperature range 90 Day and 1 Year Accuracy These long term accuracy specifications are valid for a 23 C 5 C temperature range These specifications include the initial calibration errors plus the internal DMM s long term drift errors Temperature Coefficients Accuracy is usually specified for a 23 C 5 C temperature range This is acommon temperature range for many operating environments You must add additional temperature coefficient errors to the accuracy specification if you are operating the internal DMM outside a 23 C 5 C temperature range the specification is per C 418 Chapter 9 Specifications Configuring for Highest Accuracy Measurements Configuring for Highest Accuracy Measurements The measurement configurations shown below assume that the internal DMM is in its Factory Reset state It is also assumed that manual ranging is enabled to ensure proper full scale range selection DC Voltage DC Current and Resistance Measurements e Set the resolution to 6 digits you can use the 6 digits slow mode for further noise reduction e Set the input resistance to greater than 10 Go for the 100 mV 1 V and 10 V ranges for the best de voltage accuracy e Use 4 wire ohms and enable offset compensation for the best resistance accuracy AC Voltage and AC Current Measurements e
183. alue 38 81 resolution 81 setting from front panel 81 setting from remote 81 Scan key 24 78 scan list adding channels to 78 building from front panel 78 building from remote 79 defining 23 24 examples 73 181 reading digital input 42 reading totalizer count 44 rules 73 181 scan sweep defined 78 80 scanning aborting scan 78 79 alarm mode 84 channel delay 88 clearing memory 75 78 79 external mode 83 external scan with digital input 97 initiating from front panel 78 initiating from remote 79 interval timer mode 81 interval trigger 80 manual once mode 82 memory overview 74 modules allowed 74 on alarm 84 power failure 77 reading format 87 readings stored in memory 74 removing modules during 76 rules 74 scan once manual mode 82 speeds 408 statistics 75 stopping scan 81 storing readings 76 timer interval mode 81 viewing readings 90 with alarms 75 with digital input channels 76 with external instrument 95 with Monitor function 75 with Mx B scaling 75 with totalizer channels 76 SCPI language command long form 297 command short form 297 command summary 181 200 command syntax 299 introduction 296 parameter types 300 status register system 275 syntax conventions 73 181 terminators 299 version query 149 screw terminal diagram HP 34901A 165 HP 34902A 167 HP 34903A 169 HP 34904A 171 HP 34905A 173 HP 34906A 173 HP 34907A 175 HP 34908A 177 scre
184. ample is shown below MEM STATE NAME 1 TEST_RACK_1 e f you do not specify a name note that the name parameter is optional no name is assigned to that state This provides a way to erase a name however the stored state is not deleted MEMory STATe DELete 0 1 2 3 4 5 Delete the contents of the specified storage location If you have named a storage location MEM STAT NAME command this command does not remove the name that you assigned Note that you cannot recall the instrument state from a storage location that was deleted An error is generated if you attempt to recall a deleted state 262 Chapter 5 Remote Interface Reference State Storage Commands MEMory STATe RECall AUTO OFF ON RECall AUTO Disable or enable default the automatic recall of the power down state from storage location O when power is turned on Select ON to automatically recall the power down state when power is turned on Select OFF to issue a Factory Reset and state 0 is not automatically recalled when power is turned on The AUTO query returns the automatic recall setting Returns 0 OFF or 1 ON MEMory STATe VALid 0 1 2 3 4 5 Query the specified storage location to determine if a valid state is currently stored in this location You can use this command before sending the RCL command to determine if a state has been previously stored in this location Ret
185. an alarm when a specific bit pattern is detected or when a specific count is reached Note For complete details on configuring and using alarms refer to Alarm Limits starting on page 122 e In this scan configuration you may use the Monitor function to continuously take readings on a selected channel and wait for an alarm on that channel The monitored channel can be part of the scan list but you can also use a channel on the multifunction module which does not have to be part of the scan list and you do not have to use the Monitor function For example you can generate an alarm on a totalizer channel which will initiate a scan when a specific count is reached e You can specify a scan count which sets the number of alarms that will be allowed before terminating the scan See Scan Count on page 86 for more information e All readings from the scan are stored in non volatile memory Readings accumulate in memory until the scan is terminated until the scan count is reached or until you abort the scan e Mx scaling and alarm limits are applied to measurements during the scan and all data is stored in non volatile memory e Front Panel Operation mj SCAN ON ALARM To enable the Monitor function select the desired channel and then press Toinitiate the scan press When an alarm event occurs the scan starts and readings are stored in memory Note Tostop ascan press and hold 84 Chapter 4 Features
186. an that has been started using the INITiate command send an ABORt command or Device Clear see page 302 206 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands The MEASure and CONF igure Commands Both the MEASure and CONFigure commands reset all measurement parameters to their default values For more information on the default settings for these commands see the table on page 201 e For therange parameter MIN selects the lowest range for the selected function MAx selects the highest range AUTO or DEF selects autoranging For more information on autoranging refer to General Measurement Configuration starting on page 98 e For the resolution parameter specify the resolution in the same units as the measurement function not in number of digits MIN selects the smallest value accepted which gives the highest resolution MAX selects the largest value accepted which gives the least resolution DEF Selects the default resolution which is 0 000003 x range 1 PLC For more information on resolution see the table on page 208 MEASure Command Syntax MEASure TEMPerature TCouple B E J K N R S T DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for thermocouple measurements and immediately sweep through the scan list one time Note that this command also redefines the scan list The readings are sent directly to the instrument
187. ance AC Low Frequency Filter Channel Delay Resistance Measurements Range Resolution Integration Time Offset Compensation Channel Delay Frequency Period Measurements Range Resolution AC Low Frequency Filter Channel Delay Current Measurements Range Resolution Integration Time AC Low Frequency Filter Channel Delay Default Setting C 1 PLC 0 1 C Type J Off Internal a 0 00385 Ro 1002 5 ka Automatic Delay Default Setting Autorange 512 digits 1 PLC 10 Ma fixed for all DCV ranges 20 Hz medium Automatic Delay Default Setting Autorange 512 digits 1 PLC Off Automatic Delay Default Setting Autorange 512 digits frequency 612 digits period 20 Hz medium Automatic Delay Default Setting Autorange 512 digits 1 PLC 20 Hz medium Automatic Delay 162 Chapter 4 Features and Functions Module Overview Module Overview This section gives a description of each plug in module including simplified schematics and block diagrams A wiring log is also included to make it easy to document your wiring configuration for each module For complete specifications on each plug in module refer to the module sections in chapter 9 e HP 34901A 20 Channel Multiplexer starting on page 164 e HP 34902A 16 Channel Multiplexer starting on page 166 e HP 34903A 20 Channel Actuator starting on page 168 e HP 34904A 4x8 Matrix Switch starting on page 170 e HP 34905A 6A Dual 4 Channel RF Mult
188. and CALCulate LIMit UPPer lt count gt lt ch_list gt To enable the upper limit on the specified totalizer channel use the following command CALCulate LIMit UPPer STATe ON lt ch_list gt 132 Chapter 4 Features and Functions Digital Input Operations Digital Input Operations The multifunction module HP 34907A has two non isolated 8 bit input output ports which you can use for reading digital patterns You can read the live status of the bits on the port or you can configure a scan to include a digital read The digital input channels are numbered s01 lower byte and s02 upper byte where s represents the slot number You can generate an alarm when a specific bit pattern or bit pattern change is detected on an input channel With the multifunction module the channels do not have to be part of the scan list to generate an alarm For more information see Using Alarms With the Multifunction Module on page 130 When you add a digital read toa scan list that port is dedicated to the scan The instrument issues a Card Reset to make that port an input port the other port is not affected While included in the scan list you can still perform low level read operations on the port but you cannot perform write operations on the port From the front panel you can read data from only one 8 bit input port at a time From the remote interface you can read both ports simultaneously as a
189. and Functions Scanning e Remote Interface Operation The following program segment configures the instrument to scan when an alarm occurs TRIG SOURCE ALARM1 Select the alarm configuration TRIG COUNT 2 Sweep the scan list 2 times CALC LIM UPPER 5 103 Set the upper limit CALC LIM UPPER STATE ON 103 Enable the upper limit OUTPUT ALARM1 SOURCE 103 Report alarms on Alarm 1 ROUT MON 103 Select monitor channel ROUT MON STATE ON Enable monitoring INIT Initiate the scan Note Tostop a scan send the ABORt command 85 Chapter 4 Features and Functions Scanning Scan Count You can specify the number of times the instrument will sweep through the scan list When the specified number of sweeps have occurred the scan stops Select a scan count between 1 to 50 000 scan sweeps or continuous During an Interval Scan see page 80 the scan count sets the number of times the instrument will sweep through the scan list and therefore determines the overall duration of the scan During a Scan Once operation see page 82 the scan count sets the number of front panel key presses or scan trigger commands that will be accepted before terminating the scan During an External Scan see page 83 the scan count sets the number of external trigger pulses that will be accepted before terminating the scan During an Alarm Scan see page 84 the scan count sets the number of alarms that wil
190. and a high signal disables counting The totalizer only counts when both terminals are enabled You can use either the G terminal the G terminal or both When a gate is not connected the gate terminal floats to the enabled state effectively creating a gate always condition ising Edge fA Gate Signal High True Totalizer Input Add to Total e Using the hardware jumper labeled Totalize Threshold on the module you can control the threshold at which an edge is detected Move the jumper to the AC position to detect changes through 0 volts Move the jumper to the TTL position factory setting to detect changes through TTL threshold levels A 2 5 V Threshold TTL 0 V Threshold AC 135 Chapter 4 Features and Functions Totalizer Operations e The maximum count is 67 108 863 276 1 The count rolls over to 0 after reaching the maximum allowed value e You can configure the totalizer to reset its count after it is read without losing any counts TOTalize TYPE RRESet command Then if the totalizer is included in a scan list the count will be reset on every scan sweep The count is also reset whenever it is read directly by pressing from the front panel or when sending the SENSe TOTalize DATA command e You can configure the instrument to generate an alarm when a specific count is reached on a total
191. and semicolons share a display space with the preceding character and are not considered individual characters While a message is displayed on the front panel readings from a scan or monitor are not sent to the display The following command displays a message on the front panel DISP TEXT SCANNING DISPlay TEXT CLEar Clear the message displayed on the front panel display 266 Chapter 5 Remote Interface Reference System Related Commands INSTrument DMM OFF ON DMM Disable or enable the internal DMM When you change the state of the internal DMM the instrument issues a F actory Reset RST command The DMM query returns the state of the internal DMM Returns 0 disabled or 1 enabled INSTrument DMM INSTalled Query the instrument to determine if the internal DMM is installed Returns 0 not installed or 1 installed RST Reset the instrument to the F actory configuration See Factory Reset State on page 160 in chapter 4 for a complete listing of the instrument s Factory Reset state This command is equivalent to selecting FACTORY RESET from the front panel Sto Rcl Menu SYSTem PRESet Preset the instrument to a known configuration See Instrument Preset State on page 161 in chapter 4 for a complete listing of the instrument s preset state This command is equivalent to selecting PRESET from the front panel Sto Rcl Menu SYSTem CPON 100 2
192. and string in place of a lt new line gt character A lt carriage return gt followed by a lt new line gt is also accepted Command string termination will always reset the current SCPI command path to the root level IEEE 488 2 Common Commands The EEE 488 2 standard defines a set of common commands that perform functions like factory reset self test and status operations Common commands always begin with an asterisk are four to five characters in length and may include one or more parameters The command keyword is separated from the first parameter by a blank space Use a semicolon 3 to separate multiple commands as shown below RST CLS ESE 32 OPC 299 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language SCPI Parameter Types The SCPI language defines several different data formats to be used in program messages and response messages Numeric Parameters Commands that require numeric parameters will accept all commonly used decimal representations of numbers including optional signs decimal points and scientific notation Special values for numeric parameters like MINimum MAXimum and DEFault are also accepted You can also send engineering unit suffixes with numeric parameters e g M K Or u If only specific numeric values are accepted the instrument will automatically round the input numeric parameters The following command uses a numeric parameter VO
193. asurements taken from the remote interface the resolution is fixed at 6 digits From the front panel you can set the resolution in terms of the number of digits displayed past the decimal point Measure menu For ac voltage measurements the resolution is fixed at 614 digits The only way to control the reading rate for ac measurements is by changing the channel delay see page 88 or by setting the ac filter to the highest frequency limit see page 114 100 Chapter 4 Features and Functions General Measurement Configuration e The specified resolution is used for all measurements on the selected channel If you have applied Mx scaling or have assigned alarms to the selected channel those measurements are also made using the specified resolution Measurements taken during the Monitor function also use the specified resolution e Changing the number of digits does more than just change the resolution of the instrument It also changes the integration time which is the period the instrument s analog to digital A D converter samples the input signal for a measurement See Custom A D Integration Time on page 103 for more information e The MEASure and CONFigure commands contain an optional resolution parameter which allows you to specify the resolution e Theinstrument returns to 5 digits when the measurement function is changed and after a Factory Reset RST command An Instrument Preset SySTem PRESet command o
194. ay be returned with time stamp channel number and alarm status information depending on the FORMat READing command setting see Reading Format on page 87 for more information SENS TOT DATA 303 To configure the totalizer reset mode send either of the following commands RRESet means read and reset SENSe TOTalize TYPE READ RRESet lt ch_list gt CONFigure TOTalize READ RRESet lt scan_list gt To configure the totalizer to count on the falling edge negative or rising edge positive of the input signal send the following command SENSe TOTalize SLOPe NEG POS lt ch_list gt Toimmediately clear the count on the specified totalizer channel whether scanning or not send the following command SENSe TOTalize CLEar IMMediate lt ch_list gt 137 Chapter 4 Features and Functions Digital Output Operations Digital Output Operations The multifunction module HP 34907A has two non isolated 8 bit input output ports which you can use for outputting digital patterns e The digital output channels are numbered s01 lower byte and s02 upper byte where s represents the slot number e You cannot configure a port for output operations if that port is already configured to be part of the scan list digital input e From the front panel you can write to one 8 bit output port at a time From the remote in
195. bling errors An initial unstrained gage resistance measurement is used as the reference Ro measurement from which strain AR Rg is measured For best results you should perform this reference measurement after the strain gage has been mounted to the test body The table below shows the resistance changes corresponding to 1 ue strain for common gage factor and unstrained gage resistance values Strain GF Ro AR DMM Sensitivity 1 pe 2 0 1200 0 24 ma 0 1 ma 0 4 pe 1 ue 2 0 3502 0 70 ma 1 0 MQ 1 4 pe 1 pe 2 0 10002 2 0 ma 1 0 ma 0 5 ue Using the Mx B scaling function with the equations shown below will allow you to display results directly in strain on the HP 34970A front panel display You can use a custom measurement label to display readings in uE micro strain directly The instrument will automatically add the micro u prefix based upon actual calculated values For more information on scaling see page 119 1 1 GFXRy oo nF M Temperature Effects The resistive element of a strain gage will produce a resistance change AR due to measured strain as well as changes in gage temperature This will create an apparent strain change which is undesirable A second gage of similar type can be used to detect temperature changes and thus remove this error source You should mount the second gage in close proximity and at 90 to the first gage thus responding to local temperature chang
196. by reading all of the entries A Factory Reset RST command or Instrument Preset SySTem PRESet command does not clear the alarm queue e Front Panel Operation From the front panel you can view the first 20 alarms in the queue After turning the knob to the desired channel press ClandL to view either the alarm reading or the time that the alarm occurred Notice that the annunciators indicate which alarm is being viewed ALARMS Note The alarm queue is cleared when you read the alarms 126 Chapter 4 Features and Functions Alarm Limits e Remote Interface Operation The following command reads data from the alarm queue one alarm event is read and cleared each time this command is executed SYSTEM ALARM The following is an example of an alarm stored in the alarm queue if no alarm data is in the queue the command returns 0 for each field 3 10090000E 01 C 1997 05 01 14 39 40 058 101 2 1 1 Reading with Units 31 009 C 4 Channel Number 2 Date May 1 1997 5 Limit Threshold Crossed 0 No Alarm 3 Time 2 39 40 058 PM 1 LO 2 Hl 6 Alarm Number Reported 1 2 3 or 4 The following command retrieves scanned readings and alarm data from reading memory the readings are not erased FETCH 127 Chapter 4 Features and Functions Alarm Limits Using the Alarm Output Lines Four TTL alarm outputs are available on the rear panel Alarms connector You can use thes
197. can list and take a measurement on each channel readings are not stored in memory This is an easy way to verify your wiring connections and channel configuration also valid during a scan e When you reconfigure a channel and add it to the scan list it is important to note that the previous configuration on that channel is lost For example assume that a channel is configured for dc voltage measurements When you reconfigure that channel for thermocouple measurements the previous range resolution and channel delay are set to their Factory Reset RST command state CHANNEL OFF If you decide to add that channel back to the scan list with the same function the original channel configuration including scaling and alarm values is still present e Toinitiate a scan and store all readings in memory press GD the SCAN annunciator will turn on Each time you initiate a new scan the instrument clears all previously stored readings e Tostop a scan press and hold 78 Chapter 4 Features and Functions Scanning To Build a Scan List From the Remote Interface e The MEASure CONFigure and ROUTe SCAN commands contain a scan_list parameter which defines the list of channels in the scan list Note that each time you send one of these commands it redefines the scan list To determine which channels are currently in the scan list you can send the ROUTe SCAN query command e Toinitiate a scan execute the MEASure READ
198. ce Switch Control Commands Switch Control Commands ROUTe CLOSe lt ch_list gt CLOSe EXCLusive lt ch_list gt CLOSe lt ch_list gt Close the specified channels on a multiplexer or switch module If any multiplexer channels are configured to be part of the scan list you cannot close multiple channels on that module closing one channel will open the previously closed channel On the other modules you can use the EXCL command to ensure that all channels are open before closing the specified channel The cLOS query returns the state of the specified channels Returns 1 if the channel is closed or O if the channel is open e On the 20 channel multiplexer HP 34901A only one of the shunt switches channels 21 and 22 can be dosed at a time connecting one channel will close the other e On the matrix module HP 34904A you can close multiple channels at the same time e OntheRF multiplexer modules HP 34905A 6A you can close only one channel per bank at a time closing one channel in a bank will open the previously closed channel One channel in each bank is always connected to COM These modules respond only to the ROUT CLOSe command To open a channel send the ROUT CLOSe command to another channel in the same bank ROUTe OPEN lt ch_list gt OPEN lt ch_list gt Open the specified channels on a multiplexer or switch module The OPEN query returns the state of the specified
199. ch_list gt ELay AUTO lt ch_list gt A FORMat READing ALARm OFF ON EADing ALARm EADing CHANnel OFF ON EFADing CHANnel EADing TIMI OFF ON FADing TIM EADing UNIT FADing UNIT E E p OFF ON OD 0 OD FORMat READing TIME TYPE ABSolute RELative READing TIME TYPE ABORt H ITiate READ B This command redefines the scan list when executed This command applies to all channels in the instrument Global setting Default parameters are shown in bold 184 Chapter 5 Remote Interface Reference SCPI Command Summary Scan Statistics Commands see page 233 for more information CAL Culate AVERage AVERage AVERage AVERage AVERage AVERage AVERage AVERage DAT MINimum lt ch_list gt MINimum TIME lt ch_list gt MAXimum lt ch_list gt MAXimum TIME lt ch_list gt AVERage lt ch_list gt PTPeak lt ch_list gt COUNt lt ch_list gt CLEar lt ch_list gt A LAST lt num_rdgs gt lt channel gt Scan Memory Commands see page 235 for more information DATA POINts DA A REMove lt num_rdgs gt SYSTem TIME SCAN FE R Ch lt max_count gt 185 Chapter 5 Remote Interface Reference SCPI Command
200. channel delay to any value between 0 seconds and 60 seconds with 1 ms resolution You can select a different delay for each channel The default channe delay is automatic the instrument determines the delay based on function range integration time and ac filter setting see Automatic Channel Delays on page 89 The DEL query reads the channel delay setting in seconds and returns a value in the form 1 00000000E 00 229 Chapter 5 Remote Interface Reference Scanning Overview ROUTe CHANnel DELay AUTO OFF ON lt ch_list gt CHANnel DELay AUTO lt ch_list gt Disable or enable an automatic channel delay on the specified channels If enabled the delay is determined by the function range integration time and ac filter setting see Automatic Channel Delays on page 89 Selecting a specific channel delay using the ROUT CHAN DELay command disables the automatic channel delay The AUTO query returns the automatic channel delay setting Returns 0 OFF or 1 ON ABORt Abort a scan in progress INITiate Change the state of the triggering system from the idle state to the wait for trigger state Scanning will begin when the specified trigger conditions are satisfied following the receipt of the INITiate command The readings are placed in the instrument s internal reading memory up to 50 000 readings can be stored if memory fills new readings wil
201. channel in the lower bank Source as the ch_list parameter 115 Chapter 4 Features and Functions Current Measurement Configuration Current Measurement Configuration To connect a current source to the module s screw terminals see page 21 This section contains information to help you configure the instrument for making current measurements on the HP 34901A multiplexer module This module has two fused channels for direct dc and ac current measurements on the measurement ranges shown below 10mA 100mA 1A Autorange Note Current measurements are allowed only on channels 21 and 22 on the HP 34901A module AC Low Frequency Filter The instrument uses three different ac filters which enable you to either optimize low frequency accuracy or achieve faster ac settling times The instrument selects the slow medium or fast filter based on the input frequency that you specify for the selected channels Applies to ac current and ac voltage measurements only Input Frequency Default Settling Delay Minimum Settling Delay 3 Hz to 300 kHz Slow 7 seconds reading 1 5 seconds 20 Hz to 300 kHz Medium 1 second reading 0 2 seconds 200 Hz to 300 kHz Fast 0 12 seconds reading 0 02 seconds e Theinstrument selects the medium filter 20 Hz when the function is changed or after a F actory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command
202. command 291 STATus QUES COND command 287 STATus QUES ENABle command 287 STATus QUES EVENt command 287 Step key 24 78 Sto Rcl key 36 48 stop bits RS 232 270 stopping scan 81 stored states definition 48 front panel operation 141 naming states 48 140 power down recall 140 remote operation 141 strain gage common uses 374 gage factor 374 measurements 120 373 Mx B equations 120 poisson strain 373 rosette 374 shearing strain 373 Wheatstone bridge 375 strain relief 20 335 stress strain gage 373 string parameters 301 strip length wiring 20 sweep scan defined 78 80 switch contact resistance 399 switch life 399 switch types form C SPDT 59 matrix 59 multiplexer 58 378 switching errors 381 syntax SCPI conventions 73 181 system cabling 55 335 system clock factory setting 145 setting the 22 145 system speeds 408 SYSTem ALARm command 251 268 SYSTem CPON command 260 295 SYSTem CTYPe command 265 SYSTem DATE command 264 SYSTem ERRor command 268 304 SYSTem INTerface command 269 SySTem LOCal command 269 SYSTem PRESet command 161 267 SYSTem REMote command 269 SYSTem RWLock command 269 SYSTem TIME command 264 SYSTem TIME SCAN command 236 SYSTem VERSion 268 295 SYSTem VERSion command 268 431 Index T TEMP TRAN FRTD RES command 222 TEMP TRAN FRTD TYPE command 222 TEMP TRAN RTD RES command 22
203. cross any impedances in series with the instrument s input For this reason you should apply low level ac voltages to the instrument through shielded cables You should also connect the shield to the input LO terminal Be sure to minimize the area of any ground loops that cannot be avoided A high impedance source is more susceptible to noise pickup than a low impedance source You can reduce the high frequency impedance of a source by placing a capacitor in parallel with the instrument s input terminals You may have to experiment to determine the correct capacitance value for your application Most extraneous noise is not correlated with the input signal You can determine the error as shown below Voltage Measured V Vin Noise Correlated noise while rare is especially detrimental Correlated noise will always add directly to the input signal Measuring a low level signal with the same frequency as the local power line is a common situation that is prone to this error You should use caution when switching high level and low level signals on the same module It is possible that high level charged voltages may be discharged onto a low level channel It is recommended that you either use two different modules or separate the high level signals from the low level signals with an unused channel connected to ground 342 Chapter 8 Tutorial Measurement Fundamentals Measurement Fundamentals This section explains how the
204. ctric voltages for connections between dissimilar metals Copper to Approx pV C Copper lt 0 3 Gold 0 5 Silver 0 5 Brass 3 Beryllium Copper 5 Aluminum 5 Kovar or Alloy 42 40 Silicon 500 Copper Oxide 1000 Cadmium Tin Solder 0 2 Tin Lead Solder 5 Noise Caused by Magnetic Fields If you are making measurements near magnetic fields you should take precautions to avoid inducing voltages in the measurement connections Voltage can be induced by either movement of the input connection wiring in a fixed magnetic field or by a varying magnetic field An unshielded poorly dressed input wire moving in the earth s magnetic field can generate several millivolts The varying magnetic field around the ac power line can also induce voltages up to several hundred millivolts You should be especially careful when working near conductors carrying large currents Where possible you should route cabling away from magnetic fields Magnetic fields are commonly present around electric motors generators televisions and computer monitors Also make sure that your input wiring has proper strain relief and is tied down securely when operating near magnetic fields Use twisted pair connections to the instrument to reduce the noise pickup loop area or dress the wires as close together as possible 340 Chapter 8 Tutorial System Cabling and Connections Noise Caused by Ground Loops When measuring voltages in circuits where the inte
205. cy less than 10 MHz signals only A matrix is arranged in rows and columns For example a simple 3x3 matrix could be used to connect three sources to three test points as shown below SE Source 1 Oi ee A A D S 2 KAIA a a UA A E 3t Source 3 A A va WA WA W oo exe ole Test1 Test2 Test3 Any one of the signal sources can be connected to any one of the test inputs Be aware that with a matrix it is possible to connect more than one source at the same time It is important to make sure that dangerous or unwanted conditions are not created by these connections Form C SPDT Switching The HP 34903A Actuator contains 20 Form C switches also called single pole double throw You can use Form C switches to route signals but they are typically used to control external devices Channel Open Channel Closed NC Contact Connected NO Contact Connected o NO o NO NO Normally Open NC Normally Closed o NC o NC COM 2 COM 59 Chapter 3 System Overview Measurement Input Measurement Input The HP 34970A allows you to combine a DMM either internal or external with multiplexer channels to create a scan During a scan the instrument connects the DMM to the configured multiplexer channels one at a time and makes a measurement on each channel Any channel that can be read by the instrument can also be included in a scan This includes any combination of temp
206. cy 24 Hour 21 90 Day 1 Year Coefficient C 23 C 1 C 23 C 5 C 23 C 5 C 0 C 18 C 28 C 55 C True RMS 100 0000 mV 3 Hz 5 Hz 1 00 0 03 1 00 0 04 1 00 0 04 0 100 0 004 AC Voltage l to 100 V 5 Hz 10 Hz 0 35 0 03 0 35 0 04 0 35 0 04 0 035 0 004 10 Hz 20 kHz 0 04 0 03 0 05 0 04 0 06 0 04 0 005 0 004 20 kHz 50 kHz 0 10 0 05 0 11 0 05 0 12 0 05 0 011 0 005 50 kHz 100 kHz 0 55 0 08 0 60 0 08 0 60 0 08 0 060 0 008 100 kHz 300 kHz 1 4 00 0 50 4 00 0 50 4 00 0 50 0 20 0 02 300 0000 V 3 Hz 5 Hz 1 00 0 05 1 00 0 08 1 00 0 08 0 100 0 008 5 Hz 10 Hz 0 35 0 05 0 35 0 08 0 35 0 08 0 035 0 008 10 Hz 20 kHz 0 04 0 05 0 05 0 08 0 06 0 08 0 005 0 008 20 kHz 50 kHz 0 10 0 10 0 11 0 12 0 12 0 12 0 011 0 012 50 kHz 100 kHz 0 55 0 20 0 60 0 20 0 60 0 20 0 060 0 020 100 kHz 300 kHz 4 00 1 25 4 00 1 25 4 00 1 25 0 20 0 05 Frequency 100 mV 3 Hz 5 Hz 0 10 0 10 0 10 0 005 and Period to 5 Hz 10 Hz 0 05 0 05 0 05 0 005 300 V 10 Hz 40 Hz 0 03 0 03 0 03 0 001 40 Hz 300 kHz 0 006 0 01 0 01 0 001 True RMS 10 00000 mA 3 Hz 5 Hz 1 00 0 04 1 00 0 04 1 00 0 04 0 100 0 006 AC Current and 5 Hz 10 Hz 0 30 0 04 0 30 0 04 0 30 0 04 0 035 0 006 HP 34901A Only 1 000000 A 10 Hz 5 kHz 0 10 0 04 0 10 0 04 0 10 0 04 0 015 0 006 100 0000 mA 71 3 Hz 5 Hz 1 00 0 5 1 00 0 5 1 00 0 5 0
207. d 259 ROUTe CLOSe EXCL command 259 ROUTe DONE command 260 ROUTe MON DATA command 94 ROUTe MON STATe command 94 ROUTe MON command 238 ROUTe MONitor DATA command 238 ROUTe MON STATe command 238 ROUTe OPEN command 259 260 ROUTe SCAN command 79 228 240 ROUTe SCAN SIZE command 228 240 RS 232 serial interface baud rate 152 cables 17 51 273 connection to computer 272 connector location 5 connector pinout 273 data frame format 272 flow mode 153 selecting interface 151 parity 152 troubleshooting 273 RTD measurements 110 conversion accuracy 345 measurement tutorial 346 connections 21 measurement units 106 supported types 21 106 RTS CTS flow mode RS 232 153 rubber bumpers removing 30 S safety information inside front cover Sample annunciator 4 sample programs C and C 328 Excel 7 0 321 scale temperature units 106 scaling Mx B custom label 39 120 default gain M 121 default offset B 121 equation used 119 interaction with alarms 119 null stored as offset 119 setting gain M 39 121 setting offset B 39 121 strain measurements 375 valid gain M values 120 valid offset B values 120 while scanning 75 119 SCAN annunciator 4 scan configuration copying 25 scan configuration front panel 23 scan count continuous 38 86 default value 38 86 settings 38 86 429 Index scan interval default v
208. d 4 Returns 0 3 Not Used 8 Returns 0 4 Scan in Progress 16 Instrument is scanning SCAN annunciator is on 5 Not Used 32 Returns 0 6 Not Used 64 Returns 0 7 Not Used 128 Returns 0 8 Configuration Change 256 Channel configuration was changed from the front panel This bit is cleared when a new scan is initiated 9 Memory Threshold 512 Programmed number of readings have been stored in reading memory 10 Not Used 1024 Returns 0 4 4 4 15 Not Used 32768 Returns 0 The Standard Operation event register is cleared when e You execute the cLs clear status command e You query the event register using the STATus OPER EVENt command The Standard Operation enable register is cleared when e You turn on the power PSc does not apply e You execute the STATus PRESet command e You execute the STATus OPER ENABle 0 command 285 Chapter 5 Remote Interface Reference Status System Commands Status System Commands An application program is included in chapter 7 which shows the use of the Status System Registers Refer to page 330 for more information Status Byte Register Commands See the table on page 277 for the register bit definitions STB Query the summary condition register in this register group This command is similar to a Serial Poll but it is processed like any other instrument command This command returns th
209. d Operations Display State Error Queue Stored States Factory Reset State DC Volts Autorange 5 digits 1 PLC 10 MQ fixed for all DCV ranges Automatic Delay Count Not Reset When Read Rising Edge Factory Reset State Empty All Readings are Cleared All Statistical Data is Cleared Immediate Front Panel 10 Seconds Remote Immediate Front Panel Continuous Remote 1 Scan Sweep Reading Only No Units Channel Time Stopped Factory Reset State 1 0 Vdc Factory Reset State Not Cleared Off 0 Alarm 1 Latched Mode Output Lines are Cleared Fail Low Factory Reset State Reset All Channels Open Reset All Channels Open Reset Channels s11 and s21 Selected Reset Both DIO Ports Input Count 0 Both DACs 0 Vdc Factory Reset State On Errors Not Cleared No Change 160 Chapter 4 Features and Functions Instrument Preset State Instrument Preset State The table below shows the state of the instrument after a PRESET from the Sto Rel menu or SYSTem PR Measurement Configuration Function Range Resolution Advanced Settings Totalizer Reset Mode Totalizer Edge Detect Scanning Operations Scan List Reading Memory Min Max and Average Scan Interval Source Scan Interval Scan Count Scan Reading Format Monitor in Progress Mx B Scaling Gain Factor M Scale Factor B Scale Label Alarm Limits Alarm Queue Alarm State HI and LO Alarm Limits Alarm Output
210. d current flows from the earth connection provided by the circuit to the LO terminal of the internal DMM This configuration adds no noise to the measurement However with Connection B the injected current flows through the resistor R thus adding noise to the measurement With Connection B larger values of R will make the problem worse poate 55 5 Connection A baea esda maA Beet Connection B ES AR AERS SATE The measurement noise caused by injected current can be significantly reduced by setting the integration time of the internal DMM to 1 PLC or greater see page 103 for a discussion of integration time 356 Chapter 8 Tutorial Measurement Fundamentals Loading Errors Due to Input Resistance Measurement loading errors occur when the resistance of the device under test DUT is an appreciable percentage of the instrument s own input resistance The diagram below shows this error source see a ee N Where Vs Ideal DUT voltage Rs DUT source resistance Rj Input resistance 10 MQ or gt 10 GQ oy _ 100 x Rs Error RR R To minimize loading errors set the DMM s dc input resistance to greater than 10 GQ when needed for more information on dc input resistance see page 113 357 Chapter 8 Tutorial Measurement Fundamentals Loading Errors Due to Input Bias Current The semiconductor devices used in the input circuits of the internal DMM have slight leakage curr
211. d information and a module diagram see page 170 Use this module to connect multiple instruments to multiple points on your device under test at the same time You can connect rows and columns between multiple modules to build larger matrices such as 8x8 and 4x16 with up to 96 crosspoints in a single mainframe HP 34905 6A Dual 4 Channel RF Multiplexers e HP 34905A 509 34906A 759 e 2 GHz bandwidth with on board SMB connections e 1 GHz bandwidth with SMB to BNC adapter cables provided e For detailed information and a module diagram see page 172 These modules offer wideband switching capabilities for high frequency and pulsed signals Each module is organized in two independent banks of 4 to 1 multiplexers Both modules offer low crosstalk and excellent insertion loss performance To create larger RF multiplexers you can cascade multiple banks together Only one channel in each bank may be closed at a time HP 34907A Multifunction Module e Two 8 bit Digital Input Output ports 400 mA sink 42 V open collector e 100 kHz Totalize input with 1 Vpp sensitivity e Two 12 V Calibrated Analog Outputs e For detailed information and module block diagrams see page 174 Use this module to sense status and control external devices such as solenoids power relays and microwave switches For greater flexibility you can read digital inputs and the count on the totalizer during a scan HP 34908A 40 Channel Single Ended Multipl
212. d number of bits see the table on page 203 For more information on integration time refer to Custom A D Integration Time in chapter 4 starting on page 103 SENSe TEMPerature NPLC VOLTage DC NPLC RESistance NPLC FRESistance NPLC CURRent DC NPLC lt ch_list gt MIN MAX lt ch_list gt MIN MAX lt ch_list gt MIN MAX lt ch_list gt MIN MAX lt ch_list gt MIN MAX Query the integration time on the specified channels Returns a number in the form 1 00000000E 00 218 Chapter 5 Remote Interface Reference Temperature Configuration Commands Temperature Configuration Commands See also Temperature Measurement Configuration in chapter 4 starting on page 106 General Temperature Commands UNIT TEMPerature C F K lt ch_list gt TEMPerature lt ch_list gt Select the temperature measurement units on the specified channels The default is C The TEMP query returns the temperature measurement units currently selected Returns C F or K SENSe TEMPerature TRANsducer TYPE TCouple RTD FRTD THERmistor DEF lt ch_list gt TYPE lt ch_list gt Select the type of temperature transducer to use for measurements on the specified channels Select from TC thermocouple RTD 2 wire RTD FRTD 4 wire RTD or THER thermistor The defaul
213. d the specified totalizer channels on the multifunction module but do not initiate the scan Note that this command also redefines the scan list The totalizer channel is numbered s03 where s represents the slot number Toread the totalizer during the scan without resetting the count select the READ parameter To read the totalizer during the scan and reset the count to 0 after it is read select the RRESet parameter this means read and reset CONFigure lt ch_list gt Query the present configuration on the specified channels and return a series of quoted strings If you omit the optional ch_list parameter the instrument uses the active scan list The command returns a series of comma separated fields as shown in the example below Each field contains the function range and resolution FRES 1 000000E 02 3 000000E 04 TEMP TC K 1 000000E 00 3 000000E 06 213 Chapter 5 Remote Interface Reference Setting the Function Range and Resolution Setting the Function Range and Resolution See also General Measurement Configuration in chapter 4 starting on page 98 e For 4 wire measurements the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections Specify the paired channel in the lower bank source as the ch_list channel e Current measurements are allowed only on channels 21 and 22 on the HP 34901A mu
214. d within a command string Parameter not allowed More parameters were received than expected for this command You may have entered an extra parameter or added a parameter to a command that does not require a parameter Example READ 10 Missing parameter Fewer parameters were received than expected for this command You have omitted one or more parameters that are required for this command Example ROUT CHAN DELAY Program mnemonic too long A command header was received which contained more than the maximum 12 characters allowed Example CONFIGURATION VOLT DC Undefined header A command was received that is not valid for this instrument You may have misspelled the command or it may not be a valid command If you are using the shortened form of this command remember that it may contain up to four letters Or you may have inserted an extra colon where one is not required Examples TRIGG COUN 3 or CONF VOLT DC 101 305 114 121 123 124 128 131 134 148 151 158 Chapter 6 Error Messages Execution Errors Header suffix out of range A header suffix is the number that can be appended to the end of some command headers This error is generated if an invalid number is used Example OUTP ALARM5 SOURCE 5 is not a valid alarm number Invalid character in number An invalid character was found in the number specified for a parameter Example TRIG TIMER 12 34
215. diagnose and solve the problem Application Programs Chapter 7 contains several remote interface program examples to help you develop programs for your application Tutorial Chapter 8 discusses measurement considerations and techniques to help you obtain the best accuracies and reduce sources of measurement noise Specifications Chapter 9 lists the technical specifications for the mainframe and plug in modules If you have questions relating to the operation of the HP 34970A call 1 800 452 4844 in the United States or contact your nearest Hewlett Packard Sales Office If your HP 34970A fails within three years of original purchase we will repair or replace it free of charge Call 1 800 258 5165 and ask for Express Exchange 10 Contents Chapter 1 Quick Start To Prepare the Instrument for Use 17 Installing HP BenchLink Data Logger Software 18 To Connect Wiring to a Module 20 To Set the Time and Date 22 To Configure a Channel for Scanning 23 To Copy a Channel Configuration 25 To Close a Channel 26 If the Instrument Does Not Turn On 27 To Adjust the Carrying Handle 29 To Rack Mount the Instrument 30 Chapter 2 Front Panel Overview Front Panel Menu Reference 35 To Monitor a Single Channel 37 To Set a Scan Interval 38 To Apply Mx B Scaling to Measurements 39 To Configure Alarm Limits 40 To Read a Digital Input Port 42 To Write to a Digital Output Port 43 To Read the Totalizer Count 44
216. ding queries will clear the Message Available bit To set the enable register mask and generate an SRQ service request you must write a decimal value to the register using the SRE command Bit Definitions Status Byte Register Decimal Bit Number Value Definition 0 Not Used 1 Returns 0 1 Alarm Condition 2 One or more bits are set in the Alarm Register bits must be enabled 2 Not Used 4 Returns 0 3 Questionable Data 8 One or more bits are set in the Questionable Data Register bits must be enabled 4 Message Available 16 Data is available in the instrument s output buffer 5 Standard Event 32 One or more bits are set in the Standard Event Register bits must be enabled 6 Master Summary 64 One or more bits are set in the Status Byte Register bits must be enabled 7 Standard Operation 128 One or more bits are set in the Standard Operation Register bits must be enabled The Status Byte condition register is cleared when e You execute the cLs clear status command e You read the event register from one of the other register groups only the corresponding bits are deared in the Status Byte condition register The Status Byte enable register is cleared when e You executethe SRE 0 command e You turn the power on and have previously configured the instrument to clear the enable register using the PSc 1 command Note that the enable register will not be cleared at
217. dy to receive data The modem sets the CTS line true when it is ready to accept data The instrument sets the RTS line false when the input buffer is almost full approximately 100 characters and releases the line when space is available again 271 Chapter 5 Remote Interface Reference RS 232 Interface Configuration RS 232 Data Frame Format A character frame consists of all the transmitted bits that make up a single character The frame is defined as the bits from the start bit to the last stop bit inclusively Within the frame you can select the baud rate number of data bits and parity type The instrument uses the following frame formats for seven and eight data bits Parity Start P Parity Stop EVEN ODD Bit 7 Data Bits Bit Bit Parity Start Stop NONE Bit 8 Data Bits Bit Connection to a Computer or Terminal Toconnect the instrument to a computer or terminal you must have the proper interface cable Most computers and terminals are DTE Data Terminal Equipment devices Since the instrument is alsoa DTE device you must use a DTE to DTE interface cable These cables are also called null modem modem eliminator or crossover cables The interface cable must also have the proper connector on each end and the internal wiring must be correct Connectors typically have 9 pins DB 9 connector or 25 pins DB 25 connector with a male or female pin configuration A male connector ha
218. e lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure lt ch_list gt SENSe FRESistance RANGe lt range gt MIN MAX lt ch_list gt FRESistance RANGe lt ch_list gt MIN MAX FRESistance RANGe AUTO OFF ON lt ch_list gt FRESistance RANGe AUTO lt ch_list gt SENSe FRESistance RESolution Fane MIN MAX lt ch_list gt FRESistance RESolution lt ch_list gt MIN MAX FRESistance APERture time gt EN 1 lt ch_list gt FRESistance APERture lt ch_list gt MIN MAX FRESistance NPLC 02 a 2 1 2 10 20 100 200 MIN MAX lt ch_list gt FRESistance NPLC lt ch_list gt MIN MAX SENSe FRESistance OCOMpensated OFF 0ON lt ch_list gt FRESistance OCOMpensated lt ch_ list gt B This command redefines the scan list when executed Default parameters are shown in bold 189 Chapter 5 Remote Interface Reference SCPI Command Summary Current Configuration Commands see page 224 for more information Valid only on channels 21 and 22 on the HP 34901A multiplexer module CONFigure CURRent DC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt CONFigure NSe URRen RRen URRen URRen QaQqaQqQQaow c Ch Gh er oct NSe RRen URRen QQA c ct ct NSe RRen URRen Ga
219. e RS 232 Interface Configuration RS 232 Interface Configuration See also Remote Interface Configuration in chapter 4 on page 150 This section contains information to help you use the instrument over the RS 232 interface The programming commands for RS 232 are listed on page 269 RS 232 Configuration Overview Configure the RS 232 interface using the parameters shown below Use the front panel Interface menu to select the baud rate parity number of data bits and flow control mode see page 152 for more information e Baud Rate 1200 2400 4800 9600 19200 38400 57600 factory setting 115200 e Parity and Data Bits None 8 data bits factory setting Even 7 data bits Odd 7 data bits e Flow Control None no flow control XON XOFF factory setting DTR DSR RTS CTS Modem e Number of Start Bits 1 bit fixed e Number of Stop Bits 1 bit fixed 270 Chapter 5 Remote Interface Reference RS 232 Interface Configuration RS 232 Flow Control Modes You can select one of several flow control methods to coordinate the transfer of data between the instrument and your computer or modem e None In this mode data is sent and received over the interface without any flow control used When using this method use a slower baud rate lt 9600 baud and avoid sending more than 128 characters without stopping or reading a response e XON XOFF This mode uses special characters embedded in the data stream to
220. e The SCPI Status System The Standard Event Register The Standard Event register group reports the following types of instrument events power on detected command syntax errors command execution errors self test or calibration errors query errors or the opc command is executed Any or all of these conditions can be reported to the Standard Event summary bit through the enable register To set the enable register mask you must write a decimal value to the register using the ESE command An error condition Standard Event bits 2 3 4 or 5 will record one or more errors in the instrument s error queue with the following exception A measurement overload condition is always reported in both the Standard event register bit 3 and Questionable Data event register bits 0 1 9 or 10 However no error message is recorded in the instrument s error queue Read the error queue using the SYSTem ERRor command Bit Definitions Standard Event Register Decimal Bit Number Value Definition 0 Operation Complete 1 All commands prior to and including OPC have been executed 1 Not Used 2 Returns 0 2 Query Error 4 The instrument tried to read the output buffer but it was empty Or a new command line was received before a previous query has been read Or both the input and output buffers are full 3 Device Error 8 A self test or calibration error occurred see error numbers in the 30
221. e closing one channel will open the previously closed channel Two Wire Multiplexers The HP 34901A and HP 34902A multiplexers switch both HI and LO inputs thus providing fully isolated inputs to the internal DMM or an external instrument These modules also provide a thermocouple reference junction for making thermocouple measurements for more information on the purpose of an isothermal block see page 350 Z H Channel 1 L H Channel 2 AH ji Channel 3 C H eee _ Channel 4 Oo O ML Note If any channels are configured to be part of the scan list you cannot close multiple channels closing one channel will open the previously closed channel 379 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching Four Wire Multiplexers You can make 4 wire ohms measurements using the HP 34901A and HP 34902A multiplexers For a 4 wire ohms measurement the channels are divided into two independent banks by opening the bank relay For 4 wire measurements the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections For example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 DD H To DMM Source LA Oo Bank Relay a w f Channel 2 Source To DMM Sense Channel 11 Sense LY oO L Note If any channels are configured to b
222. e etc before applying any scaling values If you change the measurement configuration scaling is turned off on that channel and the gain and offset values are reset M 1 and B 0 Scaling is also turned off when you change the temperature probe type temperature units or disable the internal DMM e If you plan to use scaling on a channel which will also use alarms be sure to configure the scaling values first f you attempt to assign the alarm limits first the instrument will turn off alarms and clear the limit values when you enable scaling on that channel If you specify a custom measurement label with scaling it is automatically used when alarms are logged on that channel e f you remove a channel from the scan list by selecting CHANNEL OFF from the front panel or by redefining the scan list from the remote interface scaling is turned off for that channel but the gain and offset values are not cleared If you decide to add that channel back to the scan list without changing the function the original gain and offset values are restored and scaling is turned back on This makes it easy to temporarily remove a channel from the scan list without entering the scaling values again e You can make a null measurement on a channel and store it as the offset B for subsequent measurements This allows you to adjust for voltage or resistive offsets through your wiring to the point of the measurement 119 Chapter 4 Featu
223. e Reference Alarm System Overview e Four TTL alarm outputs are available on the rear panel Alarms connector You can use these hardware outputs to trigger external alarm lights sirens or send a TTL pulse to your control system You can also initiate a scan sweep no external wiring required when an alarm event is logged on a channel For complete details refer to Using the Alarm Output Lines on page 128 e n addition to being stored in reading memory alarms are also recorded in their own SCPI status system You can configure the instrument to use the status system to generate a Service Request SRQ when alarms are generated See The SCPI Status System starting on page 275 for more information e The default values for the upper and lower alarm limits are 0 The lower limit must always be less than or equal to the upper limit even if you are using only one of the limits Toensure that an error is not generated when using only an upper or lower limit execute the following command sequence this example assumes that you are setting only a lower limit CALC LIMIT UPPER MAX 101 LOWER 9 101 LOWER STATE ON e A Factory Reset RST command clears all alarm limits and turns off all alarms An Instrument Preset SySTem PRESet command or Card Reset SYSTem CPON command does not clear the alarm limits and does not turn off alarms 249 Chapter 5 Remote Interface Reference Alarm Sy
224. e adequate for resistance measurements with less than 200 pF of combined cable and device capacitance This is particularly important if you are measuring resistances above 100 kQ Settling due to RC time constant effects can be quite long Some precision resistors and multifunction calibrators use large parallel capacitances 1000 pF to 0 1 uF with high resistance values to filter out noise currents injected by their internal circuitry Non ideal capacitances due to dielectric absorption soak effects in cables and other devices may have much longer settling times than expected just by RC time constants Errors will be measured when settling after the initial connection after a range change or when using offset compensation You may need to increase the channel delay time before a measurement in these situations for more information on channel delay see page 88 High Resistance Measurement Errors When you are measuring large resistances significant errors can occur due to insulation resistance and surface cleanliness You should take the necessary precautions to maintain a clean high resistance system Test leads and fixtures are susceptible to leakage due to moisture absorption in insulating materials and dirty surface films Nylon and PVC are relatively poor insulators 109 ohms when compared to PTFE Teflon insulators 10 8 ohms Leakage from nylon or PVC insulators can easily contribute a 0 1 error when measuring a 1 MQ res
225. e click on the Add Remove Programs icon 3 Select the Install Uninstall tab on the Add Remove Programs property sheet Click on Install and follow the on screen instructions If you are running Windows 3 1 1 Insert the CD ROM into your drive 2 Select File Run from the Program Manager menu bar 3 Type lt drive gt setup where drive is the letter representing your CD ROM drive Click OK to continue and follow the on screen instructions 18 Chapter 1 Quick Start Installing HP BenchLink Data Logger Software Creating Installation Floppy Disks You have the option to create an installation on floppy disks from the CD ROM installation utility This utility is provided so that you can install HP BenchLink Data Logger on a computer that does not have a CD ROM drive Note You will need a total of five 5 formatted floppy disks to create an installation 1 Go to a computer that is equipped with a CD ROM drive 2 Start the installation procedure as described on the previous page 3 Select Create disks on the initial display of the installation procedures and follow the on screen instructions On Line Help System The software is shipped with an extensive on line Help system to help you learn the features of the software as well as troubleshoot any problems that might arise as you are using the software As you are installing the software you will notice that the on line Help system is available in several langua
226. e commands For example the following statement specifies an aperture time of 2 ms for resistance measurements on channel 104 SENS RES APER 0 002 104 104 Chapter 4 Features and Functions General Measurement Configuration Autozero When autozero is enabled default the instrument internally disconnects the input signal following each measurement and takes a zero reading It then subtracts the zero reading from the preceding reading This prevents offset voltages present on the instrument s input circuitry from affecting measurement accuracy When autozero is disabled the instrument takes one zero reading and subtracts it from all subsequent measurements It takes a new zero reading each time you change the function range or integration time e Applies to temperature dc voltage 2 wire ohms and dc current measurements only Autozero is enabled when you select 4 wire ohms measurements e The autozero mode is set indirectly when you set the resolution and integration time Autozero is automatically turned off when you select an integration time less than 1 PLC e You can set autozero from the remote interface only you cannot directly set autozero from the front panel e The autozero setting is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command Remote Interface Operation The
227. e hardware outputs to trigger external alarm lights sirens or send a TTL pulse to your control system You can assign an alarm to any configured channel and multiple channels can be assigned to the same alarm number Each alarm output line represents the logical OR of all channels assigned to that alarm number an alarm on any of the associated channels will pulse the line Alarm 4 Output Alarm 3 Output Alarm 2 Output Alarm 1 Output 5 1 yord Gnd Alarms Connector You can configure the behavior of the alarm output lines as described below The behavior of the alarm annunciators on the front panel also tracks the alarm output configuration The configuration that you select is used for all four alarm output lines A Factory Reset RST command clears all four alarm outputs but does not clear the alarm queue in either configuration e Latch Mode In this mode the corresponding output line is latched true when the first alarm occurs and remains asserted until you clear it by initiating a new scan or cycling power You can manually dear the output lines at any time even during a scan and the alarm data in memory is not deared however data is cleared when you initiate a new scan e Track Mode In this mode the corresponding output line is asserted only when a reading crosses a limit and remains outside the limit When a reading returns to within limits the output line is automatically cleared Yo
228. e or more channel numbers on the module in the specified slot The channel list must be preceded with the symbol and enclosed in parentheses The following command uses a channel list parameter ROUTe CHANnel DELay lt ch_list gt e The following command configures a scan list to include only channel 10 on the module in slot 300 ROUT SCAN 310 e The following command configures a scan list to include multiple channels on the module in slot 200 The scan list now contains only channels 10 12 and 15 the scan list is redefined each time you send a new ROUTe SCAN command ROUT SCAN 210 212 215 e The following command configures a scan list to include a range of channels When you specify a range of channels the range may contain invalid channels they are ignored but the first and last channel in the range must be valid The scan list now contains channels 5 through 10 slot 100 and channel 15 slot 200 ROUT SCAN 105 110 215 301 Chapter 5 Remote Interface Reference Using Device Clear Using Device Clear Device Clear is an EEE 488 low level bus message which you can use to return the instrument to a responsive state Different programming languages and EEE 488 interface cards provide access to this capability through their own unique commands The status registers the error queue the alarm queue and all configuration states are left unchanged when a Device Clear message is received D
229. e or autoranging e Theinstrument returns to autoranging when the measurement function is changed and after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the range setting e Front Panel Operation First select the measurement function on the active channel You are automatically guided to the next level of the menu where you can select a specific range or autorange 100 mV RANGE Remote Interface Operation You can select the range using parameters in the MEASure and CONFigure commands For example the following statement selects the 10 Vdc range on channel 301 CONF VOLT DC 10 DEF 301 99 Chapter 4 Features and Functions General Measurement Configuration Measurement Resolution Resolution is expressed in terms of number of digits the instrument can measure or display on the front panel You can set the resolution to 4 5 or 6 full digits plus a 12 digit which can only be a 0 or 1 Toincrease your measurement accuracy and improve noise rejection select 6 digits To increase your measurement speed select 41 digits 5 digits 10 276 5 PDE Vp digit 25 This is the 10 Vdc range 51 2 digits are displayed Vp digit 0915 23 MVDC This is the 100 mVdc range 41 digits are displayed 113 325 6 OKA This is the 100 ohm range 61 digits are displayed For temperature me
230. e part of the scan list you cannot close multiple channels closing one channel will open the previously closed channel Channel 1 Source Channel 12 Sense When making a 4 wire measurement the test current flows through the source connections from the HI terminal through the resistor being measured To eliminate the test lead resistance a separate set of sense connections are used as shown below H EAA ia Source R Sense ANA xz era 380 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching Signal Routing and Multiplexing When used stand alone for signal routing not scanning or connected to the internal DMM multiple channels on the HP 34901A and HP 34902A multiplexers can be closed at the same time You must be careful that this does not create a hazardous condition for example connecting two power sources together Note that a multiplexer is not directional For example you can use a multiplexer with a source such as a DAC to connect a single source to multiple test points as shown below Multiplexer OUT COMH 2 2 Channel 1 K o Ct 2 pE GND COML 2 Channel 2 2 Channel 3 Channel 4 381 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching Sources of Error in Multiplexing and Switching Noise can be coupled inside a switch by the drive circuitry by switch thermal EMFs or by coupling among signal paths Noise can also be generat
231. e previous scan Therefore the contents of reading memory are always from the most recent scan 123 Chapter 4 Features and Functions Alarm Limits e Alarms are logged in the alarm queue only when a reading crosses a limit not while it remains outside the limit and not when it returns to within limits Alarm Event No Alarm Upper Limit Lower Limit e Four TTL alarm outputs are available on the rear panel Alarms connector You can use these hardware outputs to trigger external alarm lights sirens or send a TTL pulse to your control system You can also initiate a scan sweep no external wiring required when an alarm event is logged on a channel For complete details refer to Using the Alarm Output Lines on page 128 e The following table shows the different combinations of front panel annunciators that may appear while using alarms a An alarm is enabled on the displayed channel The indicated HI or LO limit is being configured on the indicated alarm shown while in the Alarm menu oe An alarm has occurred on one or more channels The behavior of the alarm output lines tracks the alarm annunciators on the front panel ALARM The alarm output lines have been cleared but alarms remain in the queue e n addition to being stored in reading memory alarms are also recorded in their own SCPI status system You can configure the instrument to use the status system to generate a Service Req
232. e same result as a Serial Poll but the Master Summary bit bit 6 is not cleared if a Serial Poll has occurred SRE lt enable_value gt SRE Enable bits in the enable register in this register group A CLS clear status will not clear the enable register but it does clear all bits in the event register A STATus PRESet does not clear the bits in the Status Byte enable register To enable bits in the enable register you must write a decimal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The SRE query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the SRE command 286 Chapter 5 Remote Interface Reference Status System Commands Questionable Data Register Commands See the table on page 280 for the register bit definitions STATus QUEStionable CONDition Query the condition register in this register group This is a read only register and bits are not cleared when you read the register A RST Factory Reset will clear all bits in a condition register A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus QUEStionable EVENt Query the event register in this register group This is a read only register Once a bit is set it remains set until cleared by this command or CLS clear status command A query of this register
233. e upper or lower case letters Therefore VOLTAGE volt and Volt areall acceptable Other forms such as VOL and VOLTAG will generate an error Braces enclose the parameter choices for a given command string The braces are not sent with the command string A vertical bar separates multiple parameter choices for a given command string Triangle brackets lt gt indicate that you must specify a value for the enclosed parameter For example the above syntax statement shows the range parameter enclosed in triangle brackets The brackets are not sent with the command string You must specify a value for the parameter Such aS VOLT DC RANG 10 Some parameters are enclosed in square brackets The brackets indicate that the parameter is optional and can be omitted The brackets are not sent with the command string If you do not specify a value for an optional parameter the instrument chooses a default value 297 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language Command Separators A colon is used to separate a command keyword from a lower level keyword You must insert a blank space to separate a parameter from a command keyword If a command requires more than one parameter you must separate adjacent parameters using a comma as shown below CONF VOLT DC 10 0 003 A semicolon is used to combine commands into one message string and can also minimize typing
234. ear the screw terminals to implement custom circuitry such as simple filters snubbers and voltage dividers The breadboard area provides the space necessary to insert your own components but there are no circuit board traces here You must add your own circuitry and signal routing Q NC o Com 01 c NO No C M 20 O D NO NOTES e You can close multiple channels at the same time on this module e The channel CLOSE and OPEN commands control the state of the Normally Open NO to COM connection on each channel For example CLOSE 201 connects the Normally Open contact to COM on channel 01 168 Chapter 4 Features and Functions HP 34903A 20 Channel Actuator I ae O WIRING LOG Slot Number J 100 200 O 300 Comments ZD 7 E 840 Z 8 Tz O 3 8 RARS 2 24 8 a TARN RERS ME 8 a s19 ELHI ZHI AS SN ON W3 SN ON WI JN ON WS JN onj W3 JN ON WD ON On WHI OHI WI IN ON W3 SN ONJ 60H3 80HI NO Normally Open NC Normally Closed LOHI Refer to the diagrams on page 20 to connect wiring to the module 20 AWG Typical Maximum Input Voltage 300 V CAT I 0 G Typical Maximum Input Current 1 A ee Maximum Switching Power 50 W 90HD
235. easurements A temperature transducer measurement is typically either a resistance or voltage measurement converted to an equivalent temperature by software conversion routines inside the instrument The mathematical conversion is based on specific properties of the various transducers The conversion routines used by the HP 34970A are compatible with the International Temperature Scale of 1990 ITS 90 The mathematical conversion accuracy not including the transducer accuracy for each transducer type is shown below Transducer Conversion Accuracy Thermocouple 0 05 C RTD 0 02 C Thermistor 0 05 C Errors associated with temperature measurements include all of those listed for de voltage and resistance measurements elsewhere in this chapter The largest source of error in temperature measurements is generally the transducer itself Your measurement requirements will help you to determine which temperature transducer type to use Each transducer type has a particular temperature range accuracy and cost The table below summarizes some typical specifications for each transducer type Use this information to help select the transducer for your application The transducer manufacturers can provide you with exact specifications for a particular transducer Parameter Thermocouple RTD Thermistor Temperature Range 210 C to 1820 C 200 C to 850 C 80 C to 150 C Measurement Type Voltage 2 or 4
236. ecifications ac measurements 406 dc measurements 404 actuator switching 59 384 address HP IB factory setting 150 selecting 3 150 address channel number 23 181 ADRS annunciator 4 Advanced key 36 104 ALARM annunciator 4 124 alarm data viewing 126 Alarm key 35 40 125 alarm limits annunciators 124 clearing alarm outputs 129 configuring 40 default settings 41 124 interaction with Mx B 40 123 output connector location 5 output connector pinout 128 output latch mode 128 output slope polarity 129 output track mode 128 scan on alarm 84 setting limits 40 with readings 87 Alarm Out key 35 129 alarm output lines clearing 129 connector location 5 connector pinout 128 latch mode 128 slope polarity 129 track mode 128 alarm queue 41 clearing 122 126 number of alarms 122 output format 127 storing alarms 122 126 alarm register status bit definitions 284 clearing bits 284 Alarms connector 128 alarms alarm output lines 128 annunciators 124 default limit values 124 description 122 front panel annunciators 124 hardware output lines 124 128 interaction with Mx B 123 output connector 128 setting limits 125 status register group 284 storing in alarm queue 122 storing in reading memory 122 viewing alarm queue 126 viewing reading memory 126 while scanning 75 with multifunction module 130 alpha a for RTDs default 110 values 110 analog to digital conversion
237. ections Shielding Techniques Shielding against noise must address both capacitive electrical and inductive magnetic coupling The addition of a grounded shield around the conductor is highly effective against capacitive coupling In switching networks this shielding often takes the form of coaxial cables and connectors For frequencies above 100 MHz double shielded coaxial cable is recommended to maximize shielding effectiveness Reducing loop area is the most effective method to shield against magnetic coupling Below a few hundred kilohertz twisted pairs may be used against magnetic coupling Use shielded twisted pair for immunity from magnetic and capacitive pickup For maximum protection below 1 MHz make sure that the shield is not one of the signal conductors Recommended Low Frequency Cable Recommended High Frequency Cable Shielded twisted pair Double shielded coaxial cable HI t A Center Conductor A ee Twisted Pair Shield Shield Foil Shield Braid PVC Jacket Separation of High Level and Low Level Signals Signals whose levels exceed a 20 to 1 ratio should be physically separated as much as possible The entire signal path should be examined including cabling and adjacent connections All unused lines should be grounded or tied to LO and placed between sensitive signal paths When making your wiring connections to the screw terminals on the module be sure to wire like functions on adjacent channels 338 Chapter
238. ed 2 64 67 108 863 100 kHz max rising or falling edge programmable 1 Vp p min 42 Vpk max OV or TTL jumper selectable TTL Hi TTL Lo or none Manual or Read Reset 85 s Analog Voltage DAC Output DAC 1 2 Resolution lout Settling Time Accuracy year 5 C Temp Coefficient 12V non isolated earth referenced 1 mv 10 mA max 1 ms to 0 01 of output of output mV 0 25 20 mV 0 015 1 mV C System Requirements 1 PC Hardware 486 66 MHz 16 MB RAM 12 MB disk space Windows 3 1 Windows 95 Windows NT 4 0 Operating System Computer Interfaces 1 HP IB HP 82335B 82340A B C 82341 A B C D National Instruments AT GPIB TNT PCI GPIB LAN to HP IB HP E2050A Windows 95 and NT only RS 232 Serial Port PC COM 1 to 4 Performance I Scan and Save to Disk 100 ch s 2 strip charts displayed 1 Software provided on CD ROM includes utility to create floppy disks for installation 2 Interface and drivers must be purchased and installed separately 3 90 MHz Pentium 20 MB RAM 412 Chapter 9 Specifications Product and Module Dimensions E Product and Module Dimensions 103 6 mm J nm l t es r 212 6mm Module T All dimensions are shown in milli
239. ed To enable the specified alarm mode send the following command CALCulate COMPare STATe ON lt ch_list gt 131 A B X OR 0 0 0 0 1 1 1 0 1 1 1 0 A B AND 0 0 0 0 1 0 1 0 0 1 1 1 Chapter 4 Features and Functions Alarm Limits Example Configuring an Alarm on a Digital Input Assume that you want to generate an alarm when a binary pattern of 1000 is read on the upper four bits of port 1 Send the following commands to configure the port for an alarm CALC COMP TYPE EQUAL 301 CALC COMP DATA 128 CALC COMP MASK 240 301 OUTPUT ALARM2 SOURCE CALC COMP STATE ON Here are the calculations used to evaluate the alarm assume that a decimal 146 was read from the port Bit 7 Bit 0 10010010 Data read from port decimal 146 10000000 CALC COMP DATA command decimal 128 00010010 X OR result 11110000 CALC COMP MASK command decimal 240 00010000 AND result no alarm generated Since the calculations produce a non zero result decimal 16 an alarm is not generated in this example Remote Interface Operation Totalizer Channel To assign the alarm number to report any alarm conditions on the specified totalizer channels use the following command OUTPut ALARm 1 2 3 4 SOURce lt ch_list gt To configure an alarm on a totalizer channel specify the desired count as the upper limit using the following comm
240. ed by the FORMat READ TIME TYPE command Returns the time in the form 1997 06 02 18 30 00 000 J une 1 1997 at 6 30 PM 233 Chapter 5 Remote Interface Reference Scanning Overview CALCulate AVERage AVERage lt ch_list gt Calculate the mathematical average of all readings taken on each of the specified channels since the start of the scan Each channel must be a multiplexer channel that has been configured to be part of the scan list If no data is available for the specified channels 0 is returned Returns a number in the form 2 61920000E 01 CALCulate AVERage PTPeak lt ch_list gt Calculate the peak to peak value of all readings taken on each of the specified channel since the start of the scan the difference between the maximum and minimum reading Each channel must be a multiplexer channel that has been configured to be part of the scan list If no data is available for the specified channels O is returned Returns a number in the form 0 00000000E 00 CALCulate AVERage COUNt lt ch_list gt Count the number of readings taken on each of the specified channels since the start of the scan Each channel must bea multiplexer channel that has been configured to be part of the scan list Returns a number in the form 5 00000000E 00 CALCulate AVERage CLEar lt ch_list gt Clear all values from the statistics registers for the specified chan
241. ed for Japanese Red White low temperature French Yellow Black K Nickel Chromium Nickel Aluminum 200 C 1370 C 1 1 C 2 2 C For oxidizing environments U S Yellow Red Good linearity British Brown Blue above 8 C DIN Red Green Japanese Red White French Yellow Purple T Copper Constantan 200 C 400 C 0 5 C 1 C Withstands moisture U S Blue Red Has a copper lead British White Blue Low temperature DIN Red Brown applications Japanese Red White French Yellow Blue E Nickel Chromium Constantan 200 C 1000 C 1 C 1 7 C_ Highest output voltage U S Purple Red Highest resolution British Brown Blue DIN Red Black Japanese Red White French Yellow Blue N Nicrosil Nisil 200 C 1300 C 1 1 C 2 2 C Superior stability to U S Orange Red K type at higher British N A N A temperatures DIN N A N A Japanese N A N A French N A N A R Platinum 13 Rhodium Rhodium 50 C 1760 C 0 6 C 1 5 C High Temperature U S Black Red Beware of contamination British White Blue Do not insert in DIN Red White metal tubes Japanese Red White French Yellow Green S Platinum 10 Rhodium Platinum 50 C 1760 C 0 6 C 1 5 C Low error good stability U S Black Red High temperature British White Blue Beware of contamination DIN Red White Do not insert in Japanese Red White metal tubes French Yellow Green Constantan Copper Nickel Nicrosil Nic
242. ed outside the network and conducted or coupled into the switch Although noise problems apply to the entire system they can become especially acute for switching Switch networks contain a high concentration of signals which magnify the errors Most problems with electric noise can be traced to improper grounding and shielding for more information on grounding and shielding see page 337 Noise can be capacitively coupled between physically adjacent channels in a switching system Noise can be coupled between the switch contacts themselves C or between adjacent cabling Caaj sa AN eZ Source Csw Source aes Cadi Source i Source 7 ay b DMM ee Capacitive noise coupling is a function of area and proximity A simple method to reduce the noise coupling is to physically separate the switches and cables from each other However this may not be practical for all applications Another solution is to keep large amplitude signals and small amplitude signals away from each other Group similar signals together high voltages low voltages analog and digital If possible use two separate switch modules one for high level signals and one for low level signals If you are using a single module for mixed signal switching leave one unused grounded channel between the groups Also ground any unused channels on the module 382 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching The
243. ed with a fixed resolution Data out of range A numeric parameter value is outside the valid range for this command Example TRIG COUNT 3 Too much data A character string was received but could not be executed because the string length was more than 12 characters This error can be generated by the CAL STRing and DISPlay TEXT commands Illegal parameter value A discrete parameter was received which was not a valid choice for this command You may have used an invalid parameter choice Example TRIG SOURCE ALARM ALARM is not a valid choice 307 230 310 350 410 420 430 440 Chapter 6 Error Messages Execution Errors Data stale A FETCh or DATA REMove command was received but internal reading memory was empty The readings retrieved may be invalid System error A firmware defect has been found This is not a fatal error but you should contact your nearest Hewlett Packard Service Center if this error is reported Error queue overflow The error queue is full because more than 10 errors have occurred No additional errors are stored until you remove errors from the queue The error queue is cleared by the CLS clear status command or when power is cycled The errors are also cleared when you read the queue Query INTERRUPTED A command was received which sends data to the output buffer but the output buffer contained data from a previous command the previous dat
244. eded on any of channels 103 205 or 320 You can also assign alarms to channels on the multifunction module For example you can generate an alarm when a specific bit pattern or bit pattern change is detected on a digital input channel or when a specific count is reached on a totalizer channel With the multifunction module the channels do not have to be part of the scan list to generate an alarm 56 Chapter 3 System Overview Signal Routing and Switching Signal Routing and Switching The switching capabilities of the plug in modules available with the HP 34970A provide test system flexibility and expandability You can use the switching plug in modules to route signals to and from your test system or multiplex signals to the internal DMM or external instruments Relays are electromechanical devices which are subject to wear out failure modes The life of a relay or the number of actual operations before failure is dependent upon how it is used applied load switching frequency and environment The HP 34970A Relay Maintenance System automatically counts the cycles of each relay in the instrument and stores the total count in non volatile memory on each switch module Use this feature to track relay failures and to predict system maintenance requirements For more information on using this feature refer to Relay Cycle Count on page 147 Switching Topologies Several switching plug in modules are available with diffe
245. efaultRM Visa_address VI_NULL VI_NULL amp dac Query the module id in slot 200 Read response and print viPrintf dac SYST CTYPE 200 n viScanf dac s amp reply_string printf Instrument identification string n s n n reply_string viPrintf dac RST n Set power on condition voltage 5 Set variable to voltage setting viPrintf dac SOURCE VOLTAGE f 205 n voltage Set output voltage Close communication session viClose dac viClose defaultRM 329 Chapter 7 Application Programs Example Programs for C and C C C Example stat_reg c stat_reg c BR K K RI KK RR A A RR A I A RA A A I A A A I A I He Required VISA library a This program demonstrates the use of the HP 34970A Status Registers for an alarm and Operation Complete OPC and for enabling and receiving K an SRQ interrupt This program also shows how to configure a scan for gi 10 readings on one channel k K A A A E E A E E A E E A E e e E E RA e e e e e e e k e e k e AR k e k RA k k A k k k k k k k k k k k k k k include lt visa h gt include lt stdio h gt include lt string h gt ViSession defaultRM ViSession DataAcqu char reply_string 256 0 double volt 10 int index count int srqFlag 0 Resource manager id Variable to identify an instrument string returned from instrument Function prototypes for SRQ
246. eference To do this an isothermal block is used to make the connections An isothermal block is an electrical insulator but a good heat conductor The additional thermocouples created at J1 and J2 are now held at the same temperature by the isothermal block Once the temperature of the isothermal block is known accurate temperature measurements can be made A temperature sensor is mounted to the isothermal block to measure its temperature Internal DMM Reference Reference Temperature Sensor Cu ot Cu Fe a Measurement Thermocouple C Cu o Cu i J2 Isothermal Block Internal or External Reference Thermocouples are available in a variety of types The type is specified by a single letter The table on the following page shows the most commonly used thermocouple types and some key characteristics of each 350 Chapter 8 Tutorial Measurement Fundamentals Thermocouple Types Temperature Probe T C Type Pos Lead Neg Lead Range Accuracy Comments B Platinum 30 Rhodium Platinum 60 Rhodium 250 C 1820 C 0 5 C High Temperature U S Gray Red Beware of contamination British N A N A Do not insert in DIN Red Gray metal tubes Japanese Red Gray French N A N A J iron Constantan 210 C 1200 C 1 1 C 2 2 C For vacuum inert U S White Red environments British Yellow Blue Least expensive DIN Red Blue Not recommend
247. el CALC SCALE STATE ON 101 To make a null measurement and store it as the offset send the following command CALC SCALE OFFSET NULL 101 121 Chapter 4 Features and Functions Alarm Limits Alarm Limits The instrument has four alarms which you can configure to alert you when a reading exceeds specified limits on a channel during a scan You can assign a high limit a low limit or both to any configured channel in the scan list You can assign multiple channels to any of the four available alarms numbered 1 through 4 For example you can configure the instrument to generate an alarm on the Alarm 1 output when a limit is exceeded on any of channels 103 205 or 320 You can also assign alarms to channels on the multifunction module For example you can generate an alarm when a specific bit pattern or bit pattern change is detected on a digital input channel or when a spedfic count is reached on a totalizer channel With the multifunction module the channels do not have to be part of the scan list to generate an alarm For complete details see Using Alarms With the Multifunction Module on page 130 Alarm data can be stored in one of two locations depending on whether a scan is running when the alarm occurs 1 If an alarm event occurs on a channel as it is being scanned then that channel s alarm status is stored in reading memory as the readings are taken Each reading that is outside
248. elf test described below A complete self test runs a series of tests and takes approximately 20 seconds to execute If all tests pass you can have a high confidence that the instrument and all installed plug in modules are operational e f the complete self test is successful PASS is displayed on the front panel If the self test fails FAIL is displayed and the ERROR annundator turns on Seethe HP 34970A Service Guide for instructions on returning the instrument to Hewlett Packard for service e Front Panel Operation To perform the complete front panel self test hold down as you turn on the instrument and hold down the key until you hear a long beep The self test will begin when you release the key following the beep e Remote Interface Operation TST Returns 0 if the self test is successful or 1 if it fails 143 Chapter 4 Features and Functions System Related Operations Display Control For security reasons or for a slight increase in scanning rates you may want to turn off the front panel display F rom the remote interface you can also display a 13 character message on the front display e You can only disable the front panel display by sending a command from the remote interface you cannot disable the front panel whilein local operation e When disabled the entire front panel display goes blank and all display annunciators except ERROR are disabled All keys except Ges are locked out when
249. emory fills new readings will overwrite the first readings stored Readings are stored in memory until you are able to retrieve them Use the FETCh command totransfer all of the readings from reading memory to the instrument s output buffer where you can read them into your computer Note that the FETCh command does not clear memory You can send the FETCh command any number of times to retrieve the same data in reading memory 204 Chapter 5 Remote Interface Reference Simplified Programming Overview Example Using MEASure The following program segment shows how to use the MEASure command to make a measurement on one channel This example configures the instrument for dc voltage measurements internally triggers the instrument to scan one channel and then sends the reading to the instrument s output buffer MEAS VOLT DC 10 0 003 301 This is the simplest way to take a reading However you do not have any flexibility with MEASure to set the scan count channel delay etc All measurement parameters except function range and resolution are preset for you automatically see the table on page 201 Example Using CONFigure With READ The following program segment shows how to use the READ command with CONFigure to make an externally triggered scan on one channel The program configures the instrument for a dc voltage measurement Using CONFigure does not place the instru
250. emote interface MEASure or INITiate command e You can start a scan when an external TTL trigger pulse is received e You can start a scan when an alarm event is logged on the channel being monitored Interval Scanning n this configuration you control the frequency of scan sweeps by selecting a wait period from the start of one sweep to the start of the next sweep called the scan to scan interval The count down time is shown on the front panel display between one scan sweep and the start of the next sweep If the scan interval is less than the time required to measure all channels in the scan list the instrument will scan continuously as fast as possible no error is generated Scan Count 1 to 50 000 scans or continuous A D Scan List 1 sweep L J 4 y Scan to Scan Interval 0 to 99 59 59 hours 80 Chapter 4 Features and Functions Scanning e You can set the scan interval to any value between 0 seconds and 99 59 59 hours 359 999 seconds with 1 ms resolution e Once you have initiated the scan the instrument will continue scanning until you stop it or until the scan count is reached See Scan Count on page 86 for more information e Mx4B scaling and alarm limits are applied to measurements during a scan and all data is stored in non volatile memory e The MEASure and CONFigure commands automatically set the scan interval to immediate 0 seconds and the scan cou
251. ent performs its power on self test The HP IB address is also displayed The instrument initially powers up with all measurement channels turned off To review the power on display with all annunciators turned on hold down as you turn on the instrument If the instrument does not turn on properly see page 27 Perform a complete self test The complete self test performs a more extensive set of tests than those performed at power on Hold down as you turn on the instrument and hold down the key until you hear a long beep The self test will begin when you release the key following the beep If the self test fails see the HP 34970A Service Guide for instructions on returning the instrument to Hewlett Packard for service 17 Chapter 1 Quick Start Installing HP BenchLink Data Logger Software Installing HP BenchLink Data Logger Software If you ordered the HP 34970A with the internal DMM then the HP BenchLink Data Logger software is included The software is shipped on one CD ROM but includes a utility to build installation floppy disks To install the software on your PC you will need a minimum of 12 MB of free disk space For system requirements and additional details on the features of the software refer to the specifications in chapter 9 Installation Procedure If you are running Windows 95 or Windows NT 4 0 1 Insert the CD ROM into your drive 2 Select Settings Control Panel from the Start menu Doubl
252. ent issues a Card Reset to open all channels on that module You cannot perform low level close or open operations on any channels on that module even those channels that are not configured e Whilea scan is running you can perform some low level control operations on modules that do not contain channels in the scan list For example you can open or close channels or issue a Card Reset on switching modules that do not contain channels in the scan list However you cannot change any parameters that affect the scan channel configuration scan interval scaling values alarm limits Card Reset etc while a scan is running 75 Chapter 4 Features and Functions Scanning When you add a digital read multifunction module to a scan list that port is dedicated to the scan The instrument issues a Card Reset to make that port an input port the other port is not affected While a scan is running you can perform low level control operations on any channels on the multifunction module that are not in the scan For example you can output a DAC voltage or write to a digital port even if the totalizer is part of the scan list However you cannot change any parameters that affect the scan channel configuration scan interval Card Reset etc while a scan is running If a scan includes a read of the totalizer multifunction module the count is reset each time it is read during the scan only when the totalizer reset mode is enabled T
253. ents called bias currents The effect of the input bias current is a loading error at the internal DMM s input terminals The leakage current will approximately double for every 10 C temperature rise thus making the problem much more apparent at higher temperatures Rs MN gt HI Vs a LO Where Ip DMM bias current Rs DUT source resistance Rj Input resistance 10 MQ or gt 10 GQ C DMM input capacitance Error V Ip x Rs 358 Chapter 8 Tutorial Measurement Fundamentals AC Voltage Measurements The main purpose of an ac front end is to change an ac voltage input into a de voltage which can be measured by the ADC Signal Conditioning for AC Measurements Input signal conditioning for ac voltage measurements includes both attenuation and amplification An input coupling capacitor C blocks the dc portion of the input signal so that only the ac component is measured Ranging is accomplished by combining signal attenuation from the first stage amplifier and gain from the second stage amplifier X 0 01 Ss AVA X1 1 Mo AA O HI 3 A1 AC to DC LO al gt A2 gt 71 H Converter gt EA e e x0 A X10 A The first stage implements a high input impedance 1 MQ switchable compensated attenuator The second stage provides variable gain signal amplification to scale the input to the ac converter to the
254. equency Power Consumption Operating Environment Storage Environment Weight Mainframe Safety RFI and ESD Warranty 100 V 120 V 220 V 240 V 10 45 Hz to 66 Hz automatically sensed 12 W 25 VA peak Full accuracy for 0 C to 55 C Full accuracy to 80 R H at 40 C 40 C to 70 C Pl Net 3 6 kg 8 0 Ibs Conforms to CSA UL 1244 IEC 1010 Cat I CISPR 11 IEC 801 2 3 4 3 years 1 Reading speeds for 60 Hz and 50 Hz operation autozero OFF 2 For fixed function and range readings to memory scaling and alarms off autozero OFF 3 Maximum limit with default settling delays defeated 4 Speeds are for 41 digits delay 0 display off autozero off Using 115 kbaud RS 232 setting 5 Storage at temperatures above 40 C will decrease battery life 408 Chapter 9 Specifications Module Specifications HM Module Specifications HP 34901A 34902A 34908A 34903A 34904A Multiplexer Actuator Matrix General 34901A 34902A 34908A 34903A 34904A Number of Channels 20 2 16 40 20 4x8 2 4 wire 2 4 wire 1 wire SPDT 2 wire Connects to Internal DMM Yes Yes Yes No No Scanning Speed 60 ch s 250 ch s 60 ch s Open Close Speed 120 s 120 s 70 s 120 s 120 s Maximum Input Voltage dc ac rms 300 V 300 V 300 V 300 V 300 V Current dc ac rms 1A 50 mA 1A 1A 1A Power W VA 50 W 2W 50 W 50 W 50 W Isolation ch c
255. eral 34905A 34906A AC Characteristics 34905A 34906A Number of Channels Dual 1x4 Dual 1x4 Bandwidth l 2 GHz 2 GHz 502 75Q Insertion Loss dB 10MHz 01 0 1 Open Close Speed 60 s 100 MHz 0 4 0 4 Maximum Input 500 MHz 0 6 0 5 Voltage dc ac rms 42 V 1 GHz 1 0 1 0 Current dc ac rms 0 7A 1 5 GHz 1 2 1 5 Power W VA 20 W 2 GHz 3 0 2 0 DC Characteristics C swR 40MHz io io Offset Voltage lt 6uV 100MHz 1 05 1 05 Initial Closed Channel R lt 0 52 500 MHz 1 20 1 25 Isolation ch ch ch earth gt 1GQ 1 GHz 1 20 1 40 Other 1 5 GHz 1 30 1 40 Switch Life No Load typical 5M 2 GHz 1 40 2 00 Switch Life Rated Load typical 7 100k Ch Ch Cross Tak dB 4l 10 MHz 100 85 Temperature Operating 0 C to 55 C 100 MHz 85 75 Temperature Storage 20 C to 70 C 500 MHz 65 65 Humidity non condensing 40 C 80 R H 1 GHz 55 50 1 5 GHz 45 40 2 GHz 35 35 Risetime lt 300 ps Signal Delay lt 3ns Capacitance HI to LO lt 20 pF Volt Hertz Limit 10 1 Errors included in DMM measurement accuracy specifications 2 Applies to resistive loads only 3 Bandwidth direct to module SMB connectors 4 50Q source 50Q load 410 Chapter 9 Specifications Typical AC Performance Graphs Typical AC Performance Graphs HP 34905A 34906A Insertion Loss 50Q OdB 1 dB re Lt itt N 2dB N 3 dB 4dB 10 MHz 100 MHz 1 GHz 3 GH
256. erature voltage resistance current frequency or period measurements on multiplexer channels A scan can also include a read of a digital port or a read of the totalizer count on the multifunction module The Internal DMM A transducer or sensor converts a physical quantity being measured into an electrical signal which can be measured by the internal DMM To make these measurements the internal DMM incorporates the following functions e Temperature thermocouple RTD and thermistor e Voltage dc and ac up to 300V e Resistance 2 wire and 4 wire up to 100 MQ e Current dc and ac up to 1A e Frequency and Period up to 300 kHz The internal DMM provides a universal input front end for measuring a variety of transducer types without the need for additional external signal conditioning The internal DMM includes signal conditioning amplification or attenuation and a high resolution up to 22 bits analog to digital converter A simplified diagram of the internal DMM is shown below re Tal To From nalog nalog to Earth 7 O Signal n Main ate Input gt ee Amp gt Digital A Referenced Signal Conditioning Pa Converter Processor Ne Section AT Optical Isolators A 60 Chapter 3 System Overview Measurement Input Signal Conditioning Ranging and Amplification Analog input signals are multiplexed into the internal DMM s signal cond
257. erminals see page 21 This section contains information to help you configure the instrument for making resistance measurements Use the 2 wire method for ease of wiring and higher density or the 4 wire method for improved measurement accuracy The measurement ranges are shown below 1002 1kQ 10kQ 100kQ 1MQ 10MQ 100MQ Autorange Offset Compensation Offset compensation removes the effects of any dc voltages in the circuit being measured The technique involves taking the difference between two resistance measurements on the specified channels one with the current source turned on and one with the current source turned off Applies only to 2 wire and 4 wire ohms measurements on the 1009 1 kO and 10 kQ ranges e For detailed information about offset compensation see page 371 e Theinstrument disables offset compensation when the measurement function is changed or after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the setting e Front Panel Operation First select the 2 wire or 4 wire ohms function on the active channel Then go to the Advanced menu and enable or disable offset compensation OCOMP ON e Remote Interface Operation ES OCOM ON 203 Enable offset compensation 2 wire FRES OCOM ON 208 Enable offset compensation 4 wire ve For 4 wire measurements specify the paired
258. es using an external power supply and two digital output channels The HP 865A switch provides an internal protection diode The state of the 2 to 1 multiplexer is changed by setting the appropriate output bit low 0 Digital Output Channel HP 865X Microwave Switch 24 Volt Power Supply 394 Chapter 8 Tutorial Multifunction Module Totalizer The HP 34907A module has a 26 bit totalizer which can count pulses at a 100 kHz rate You can manually read the totalizer count or you can configure a scan to read the count Totalizer Software On Off Reset Input Signal R 1V to 42V a O ja Counter Data Signal Conditioning l G2 Gate Input _ G2 GND2 al a ee TTL AC Threshold Jumper e You can configure the totalizer to count on the rising edge or falling edge of the input signal e Using the hardware jumper labeled Totalize Threshold on the module you can control the threshold at which an edge is detected Move the jumper to the AC position to detect changes through 0 volts Move the jumper to the TTL position factory setting to detect changes through TTL threshold levels 2 5 V Threshold TTL 0 V Threshold AC AN EX VU e The maximum count is 67 108 863 276 1 The count rolls over to 0 after reaching the maximum allowed value 395 Chapter 8 Tutorial Multifunction Module e You can control
259. es between 12 volts with 16 bits of resolution Each DAC Digital to Analog Converter channel can be used as a programmable voltage source for analog input control of other devices A simplified diagram is shown below 16 4 7 2 Channel 04 16 gt Channel 05 VW e You can set the output voltage to any value between 12 Vdc and 12 Vdc in 1 mV steps Each DAC is earth referenced it cannot float e Each DAC channel is capable of supplying 10 mA maximum current Note You must limit the output current to 40 mA total for all three slots six DAC channels 68 Chapter 3 System Overview Control Output The Actuator General Purpose Switch You can think of the HP 34903A Actuator as a control output because it is often used to control external power devices The actuator provides 20 independent isolated Form C SPDT switches Channel Open Channel Closed NC Contact Connected NO Contact Connected o NO o NO NO Normally Open ae NC Normally Closed o NC o NC i________ COM COM Each channel can switch up to 300V dc or ac rms Each switch can also switch up to 1 A dc or ac rms up to 50 W maximum For example the maximum current that you can switch at 120 V is 0 45 A as shown below Voltage 300 120 100 50 30 Current For control applications the actuator has the following advantages e Higher voltage and power rating than the digital o
260. es but rejecting strain changes Subtracting measurements from the second gage will remove any undesirable strain errors 375 Chapter 8 Tutorial Measurement Fundamentals Frequency and Period Measurements The internal DMM uses a reciprocal counting technique to measure frequency and period This method generates constant measurement resolution for any input frequency The internal DMM s ac voltage measurement section performs input signal conditioning for frequency and period measurements Reset 1 Analog Signal Input Conditioning Counter Latch N GOO 01s 1s 1s Timebase 6 MHz and Divider The timebase is divided to provide a gate signal The gate signal and input signal are combined to enable the counter During the on time the counter counts the 6 MHz timebase signal At the end of each gate period the total count is latched and the result is divided by the known timebase frequency to determine the input frequency The counter is then reset before the next gate period The resolution of the measurement is tied to the timebase and not the input frequency This increases measurement speed especially at low frequencies The reciprocal counter has the advantage of a constant number of digits of display no matter what the input frequency is With a reciprocal counter the number of digits of resolution scales with the gate time If a 1 second gate gi
261. es the time from the start of one scan sweep to the start of the next sweep You can set the interval to any value between 0 seconds and 359 999 seconds 99 59 59 hours with 1 ms resolution MIN 0 seconds MAX 359 999 seconds The TIM query returns the scan to scan interval in seconds in the form 1 00000000E 01 TRIGger COUNt lt value gt MIN MAX INFinity COUNt Select the number of times that the instrument will sweep through the scan list a sweep is one pass through the scan list When the specified number of sweeps have occurred the scan stops Select a scan count between 1 to 50 000 sweeps or continuous INFinity MIN 1 sweep MAX 50 000 sweeps The COUN query returns the scan count in the form 1 00000000E 01 If you specified a continuous scan count the query command returns 9 90000200E 37 ROUTe CHANnel DELay lt seconds gt lt ch_list gt CHANnel DELay lt ch_list gt Add a delay between multiplexer channels in the scan list useful for high impedance or high capacitance circuits The delay is inserted between the relay closure and the actual measurement on the channel You can set the channel delay to any value between 0 seconds and 60 seconds with 1 ms resolution You can select a different delay for each channel The DEL query reads the channe delay setting in seconds and returns a value in the form 1 00000000E 00 241 Chapter 5 Remote Inte
262. esent with dc signals on the input This is called normal mode rejection or NMR Normal mode noise rejection is achieved when the internal DMM measures the average of the input by integrating it over a fixed period If you set the integration time to a whole number of power line cycles PLCs of the spurious input these errors and their harmonics will average out to approximately zero When you apply power to the internal DMM it measures the power line frequency 50 Hz or 60 Hz and uses this measurement to determine the integration time The table below shows the noise rejection achieved with various configurations For better resolution and increased noise rejection select a longer integration time Integration Time PLCs Digits Bits 60 Hz 50 Hz NMR 0 02 412 15 400 us 400 us 0 dB 0 2 51 2 18 3 ms 3 ms 0 dB 1 512 20 16 7 ms 20 ms 60 dB 2 61 2 21 33 3 ms 40 ms 90 dB 10 61 2 24 167 ms 200 ms 95 dB 20 6 25 333 ms 400 ms 100 dB 100 6 26 1 67 s 2s 105 dB 200 6t2 26 3 33 s 4s 110 dB The following graph shows the attenuation of ac signals measured in the dc voltage function for various A D integration time settings Note that signal frequencies at multiples of 1 T exhibit high attenuation 0 dB T 10dB F 4 amp Oo oO 20dB F 4 2 D 30 dB 40 dB 0 1 1 10 Signal Frequency x T 344 Chapter 8 Tutorial Measurement Fundamentals Temperature M
263. esistor can be installed in the R2 location The resultant voltage drop transducer current through the resistor can be measured by the internal DMM Thus the 50Q resistor converts the 4 to 20 mA current to a 0 2 to 1 volt signal 387 Chapter 8 Tutorial Matrix Switching Matrix Switching A matrix switch connects multiple inputs to multiple outputs and therefore offers more switching flexibility than a multiplexer Use a matrix for switching low frequency less than 10 MHz signals only A matrix is arranged in rows and columns For example a simple 3x3 matrix could be used to connect three sources to three test points as shown below x S Source 1 ZA ZA ae Z a o Source 2 A yr N o Source 3 YY Ww an heey Neda Test1 Test2 Test3 Any one of the signal sources can be connected to any one of the test inputs Be aware that with a matrix it is possible to connect more than one source at the same time It is important to make sure that dangerous or unwanted conditions are not created by these connections 388 Chapter 8 Tutorial Matrix Switching Combining Matrices You can combine two or more matrix switches to provide more complex switching For example the HP 34904A provides a 4 row by 8 column matrix You can combine two of these modules as either a 4 row by 16 column matrix or an 8 row by 8 column matrix An 8x8 matrix is shown below Matrix Module 1
264. etc before setting any alarm limits If you change the measurement configuration alarms are turned off and the limit values are cleared Alarms are also turned off when you change the temperature probe type temperature units or disable the internal DMM e f you plan to use alarms on a channel which will also use scaling be sure to configure the scaling values first f you attempt to assign the alarm limits first the instrument will turn off alarms and clear the limit values when you enable scaling on that channel If you specify a custom measurement label with scaling it is automatically used when alarms are logged on that channel e f you redefine the scan list alarms are no longer evaluated on those channels during a scan but the limit values are not cleared If you decide to add a channel back to the scan list without changing the function the original limit values are restored and alarms are turned back on This makes it easy to temporarily remove a channel from the scan list without entering the alarm values again e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan Therefore the contents of reading memory are always from the most recent scan e Alarms are logged in the alarm queue only when a reading crosses a limit not while it remains outside the limit and not when it returns to within limits 248 Chapter 5 Remote Interfac
265. etermining the minimum allowable circuit capacitance is Ctot lo 300 x L where L is the inductance of the load and Io is the current value calculated earlier The total circuit capacitance C is actually made up of the wiring capacitance plus the value of the protection network capacitor Cp Therefore the minimum value for Cp should be the value obtained for the total circuit capacitance C Note that the actual value used for Cp should be substantially greater than the value calculated for C Using Varistors Use a varistor to add an absolute voltage limit across the relay contacts Varistors are available for a wide range of voltage and clamp energy ratings Once the circuit reaches the voltage rating of the varistor the varistor s resistance declines rapidly A varistor can supplement an RC network and is especially useful when the required capacitance Cp is too large 386 Chapter 8 Tutorial Actuators and General Purpose Switching Using Attenuators Provisions have been made on the HP 34903A circuit board for installing simple attenuators or filter networks An attenuator is composed of two resistors that act as a voltage divider A typical attenuator circuit is shown below Br R1 O O HI Vsignal R2 Vatt To select the attenuator components use the following equation R2 Vatt Vsignal X R Pe One typical use for the shunt component is with 4 to 20 mA transducers A 509 1 0 5 watt r
266. evice Clear performs the following actions e fascanis running it is aborted e Theinstrument returns to the scan trigger idle state e Theinstrument s input and output buffers are cleared e Theinstrument is prepared to accept a new command string For RS 232 operation sending the lt C rl C gt character will perform the equivalent operations of the E E E 488 Device Clear message Note The ABORt command is the recommended way to terminate a scan 302 Error Messages Error Messages e Errors are retrieved in first in first out FIFO order The first error returned is the first error that was stored Errors are cleared as you read them When you have read all errors from the queue the ERROR annunciator turns off and the errors are cleared The instrument beeps once each time an error is generated e Ifmore than 10 errors have occurred the last error stored in the queue the most recent error is replaced with Error queue overflow No additional errors are stored until you remove errors from the queue If no errors have occurred when you read the error queue the instrument responds with No error e The error queue is cleared by the CLS clear status command or when power is cycled The errors are also cleared when you read the queue The error queue is not cleared by a Factory Reset RST command or an Instrument Preset SYSTem PRESet command e Front Panel Operation ERRORS
267. exer e 40 channels of 300 V single ended common LO switching e Built in thermocouple reference junction e Switching speed of up to 60 channels per second e Connects to the internal multimeter e For detailed information and a module diagram see page 176 Use this module for high density switching applications which require single wire inputs with a common LO All relays are break before make to ensure that only one relay is connected at any time In This Book Quick Start Chapter 1 helps you get familiar with a few of the instrument s front panel features This chapter also shows how to install the HP BenchLink Data Logger software Front Panel Overview Chapter 2 introduces you to the front panel menus and describes some of the instrument s menu features System Overview Chapter 3 gives an overview of a data acquisition system and describes how parts of a system work together Features and Functions Chapter 4 gives a detailed description of the instrument s capabilities and operation You will find this chapter useful whether you are operating the instrument from the front panel or over the remote interface Remote Interface Reference Chapter 5 contains reference information to help you program the instrument over the remote interface using the SCPI language Error Messages Chapter 6 lists the error messages that may appear as you are working with the instrument Each listing contains enough information to help you
268. explanation 61 integrating technique 61 non integrating technique 61 annunciators 4 124 aperture time command syntax 217 definition 103 selecting 103 application programs C and C 328 Excel 7 0 321 322 attenuation 336 344 387 auto answer modem 274 automatic channel delays 89 automatic recall power down 48 77 autorange threshold values 98 421 Index autozero definition 105 vs integration time 105 average responding error 360 average during scan 75 AWG wire gauge size 336 B B Mx B scaling offset 119 backplane relays 164 166 276 383 bandwidth ac ac current 116 ac voltage 114 vs channel delays 89 bank switch 164 166 176 383 battery life 408 baud rate RS 232 factory setting 47 152 selecting 47 152 BBM switching 378 BenchLink Data Logger Software creating floppy disks 19 installation 18 19 on line help 19 software overview 6 system specifications 412 bias current dc loading errors 358 binary format digital read 42 133 bits vs integration time 103 203 block diagram HP 34970A 53 internal DMM 60 BNC cable kits HP 34905A 173 HP 34906A 173 boolean parameters 300 braces syntax 73 181 brackets syntax 73 181 break before make switching 378 bridge strain gage 375 buffering triggers 83 bumpers removing 30 burden voltage 368 Cc C and C example programs 328 cable kits SMB to BNC HP 34905A 173 H
269. frequencies Error 100 x d V 1 2nxFxR xC F Input frequency Rs Source resistance Cin Input capacitance 150 pF Cable capacitance Use low capacitance cable when measuring high frequency ac signals see page 336 364 Chapter 8 Tutorial Measurement Fundamentals Low Level AC Measurement Errors When measuring ac voltages less than 100 mV be aware that these measurements are especially susceptible to errors introduced by extraneous noise sources An exposed test lead will act as an antenna and the internal DMM will measure the signals received The entire measurement path including the power line act as a loop antenna Circulating currents in the loop will create error voltages across any impedances in series with the instrument s input For this reason you should apply low level ac voltages to the instrument through shielded cables You should also connect the shield to the input LO terminal Be sure to minimize the area of any ground loops that cannot be avoided A high impedance source is more susceptible to noise pickup than a low impedance source You can reduce the high frequency impedance of a source by placing a capacitor in parallel with the instrument s input terminals You may have to experiment to determine the correct capacitance value for your application Most extraneous noise is not correlated with the input signal You can determine the error as shown below Voltage Measured
270. full scale level Any residual dc offset from the attenuator and amplifier stages is blocked by a capacitor An ac voltage front end similar to the one discussed above is also used to measure ac current Shunt resistors convert the ac current into an ac voltage which can then be measured Current shunts are switched to provide selectable ac current ranges 359 Chapter 8 Tutorial Measurement Fundamentals True RMS AC Measurements True RMS responding multimeters measure the heating potential of an applied voltage Unlike an average responding measurement a true RMS measurement is used to determine the power dissipated in a resistor The power is proportional to the square of the measured true RMS voltage independent of waveshape An average responding ac multimeter is calibrated to read the same as a true RMS meter for sinewave inputs only For other waveform shapes an average responding meter will exhibit substantial errors as shown below Waveform Crest Factor Average Shape C F AC RMS AC DC RMS Responding Error Calibrated for O err Ray a 1 414 1 414 t Qe The internal DMM s ac voltage and ac current functions measure the ac coupled true RMS value This is in contrast to the ac dc true RMS value shown above Only the heating value of the ac component of the input waveform is measured dc is rejected For sinewaves triangle waves and square waves the ac and ac dc values are equa
271. fuse 27 selection 27 selector module 5 28 power line rejecting noise 344 preset state 161 printing history inside front cover product dimensions 413 414 programming examples C and C 328 329 Excel 7 0 321 322 323 programming language command summary 181 200 syntax conventions 181 programming overview 201 206 PT100 RTD 110 346 questionable data register bit definitions 280 clearing bits 281 Quick Start Kit 17 R Ro RTD default 110 range 110 R command 236 rack mounting filler panel 31 flange kit 31 lock link kit 31 removing bumpers 30 removing handle 30 sliding shelf kit 31 radio frequency interference 339 random noise 377 range autorange 98 command syntax 215 overload 98 selecting 99 ranges by function 2 wire ohms 21 116 4 wire ohms 21 115 ac current 21 116 ac voltage 21 113 dc current 21 116 dc voltage 21 113 RC protection circuitry 385 Read key 42 44 428 Index READ command 79 204 230 description 202 examples 205 reading format 87 readings memory storing alarms 122 readings viewing 24 90 real time clock factory setting 145 setting 22 145 rear panel pictorial overview 5 external scanning 95 recall power down state 140 reference junction thermocouple definition 107 external reference 107 fixed temperature 107 internal reference 107 reference channel 107 220 reference thermocouple 349 register diagram
272. g lt quoted_string gt STRing CALibration VALue lt value gt VALue Service Related Commands see page 294 for more information INSTrument DMM OFF ON DMM DMM INSTalled DIAGnostic DMM CYCLes DMM CYCLes CLEar 1 2 3 DIAGnostic RELay CYCLes lt ch_list gt RELay CYCLes CLEar lt ch_list gt RST SYSTem PRESet SYSTem Q PON 100 200 300 ALL SYSTem VERSion TST Default parameters are shown in bold 199 Chapter 5 Remote Interface Reference SCPI Command Summary IEEE 488 2 Common Commands CLS ESR ESE lt enable_value gt x E S F IDN OPC OPG PSC 0 1 PSC RST STB SRE lt enable_value gt SRE TRG TST 200 Chapter 5 Remote Interface Reference Simplified Programming Overview Simplified Programming Overview This section gives an overview of the basic techniques used to program the HP 34970A over the remote interface This section is only an overview and does not give all of the details you will need to write your own application programs Refer to the remainder of this chapter and also the application examples in chapter 7 You may also want to refer to the programming reference manual that came with your computer for details on outputting command strings and entering data The MEASure and CONFigure commands provide the most straight
273. g HP BenchLink Data Logger Software on page 18 e To Connect Wiring to a Module on page 20 e To Set the Time and Date on page 22 e To Configure a Channel for Scanning on page 23 e To Copy a Channel Configuration on page 25 e To Close a Channel on page 26 e Ifthe Instrument Does Not Turn On on page 27 e To Adjust the Carrying Handle on page 29 e To Rack Mount the Instrument on page 30 16 On Standby Switch WARNING Note that this switch is Standby only To disconnect the mains from the instrument remove the power cord 2 Chapter 1 Quick Start To Prepare the Instrument for Use To Prepare the Instrument for Use Check the list of supplied items Verify that you have received the following items with your instrument If anything is missing contact your nearest Hewlett Packard Sales Office One power cord This User s Guide One Service Guide One Quick Reference Guide Certificate of Calibration if you ordered the internal DMM Quick Start Package if you ordered the internal DMM e One RS 232 cable e HP BenchLink Data Logger Software CD ROM To install the software see page 18 e One J type thermocouple and a flatblade screwdriver Any plug in modules that you ordered are delivered in a separate shipping container Connect the power cord and turn on the instrument The front panel display will light up briefly while the instrum
274. g a Serial Poll Using STB to Read the Status Byte The STB command is similar toa Serial Poll but it is processed like any other instrument command The STB command returns the same result as a Serial Poll but bit 6 is not cleared as long as the enabled conditions remain The STB command is not handled automatically by the E E E 488 bus interface hardware and will be executed only after previous commands have completed You cannot clear an SRQ using the STB command 278 Chapter 5 Remote Interface Reference The SCPI Status System Using the Message Available Bit MAV You can use the Status Byte Message Available bit bit 4 to determine when data is available to read into your computer The instrument subsequently clears bit 4 only after all messages have been read from the output buffer To Interrupt Your Bus Controller Using SRQ 1 Send a Device Clear message to clear the instrument s output buffer eg CLEAR 709 2 Clear the event registers using the CLS command 3 Set up the enable register masks E xecute the ESE command to configure the Standard Event enable register and the SRE command to configure the Status Byte enable register 4 Send the opc command and enter the result to ensure synchronization 5 Enable your computer s EEE 488 SRQ interrupt To Determine When a Command Sequence is Completed 1 Send a Device Clear message to clear the instrument s output buffer
275. g units time stamps scanned measurements and stores data in non volatile memory Scanning The instrument allows you to combine a DMM either internal or external with multiplexer channels to create a scan During a scan the instrument connects the DMM to the configured multiplexer channels one at a time and makes a measurement on each channel Before you can initiate a scan you must set up a scan list to include all desired multiplexer or digital channels Channels which are not in the scan list are skipped during the scan The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300 Measurements are taken only during a scan and only on those channels which are included in the scan list You can store up to 50 000 readings in non volatile memory during a scan Readings are stored only during a scan and all readings are automatically time stamped Each time you start a new scan the instrument clears all readings stored in memory from the previous scan Therefore all readings currently stored in memory are from the most recent scan 62 Chapter 3 System Overview Measurement Input You can configure the event or action that controls the onset of each sweep through the scan list a sweep is one pass through the scan list e You can set the instrument s internal timer to automatically scan at a specific interval as shown below You can also program a time delay between channels in
276. ge for all inputs between 3 Hz and 300 kHz The range parameter is required only to specify the resolution Therefore it is not necessary to send a new command for each new frequency to be measured Use the resolution parameter to specify the desired resolution for the measurement Setting the resolution also sets the integration time for the measurement The following table shows the relationship between integration time measurement resolution number of digits and number of bits Integration Time Resolution Digits Bits 0 02 PLC lt 0 0001 x Range 4 Digits 15 0 2 PLC lt 0 00001 x Range 5 Digits 18 1 PLC lt 0 000003 x Range 5 Digits 20 2 PLC lt 0 0000022 x Range 6 Digits 21 10 PLC lt 0 000001 x Range 61 Digits 24 20 PLC lt 0 0000008 x Range 61 Digits 25 100 PLC lt 0 0000003 x Range 6 Digits 26 200 PLC lt 0 00000022 x Range 6 Digits 26 Specify the resolution in the same units as the measurement function not in number of digits For example for dc voltage measurements specify the desired resolution in volts For resistance specify the desired resolution in ohms For frequency specify the desired resolution in hertz 203 Caution Chapter 5 Remote Interface Reference Simplified Programming Overview Using the READ Command The READ command changes the state of the scan trigger system from the idle state to the wait for trigger state Scanning will beg
277. ge DC 101 121 e f you select a range of channels in a command which specifies an illegal operation on one or more channels the instrument will skip the illegal channels and will not generate an error For example the following command will not generate an error on the HP 34901A module even though channels 121 and 122 are for current measurements only CONFigure VOLTage DC 101 220 However if the illegal channel is one of the end points in the range the instrument will generate an error For example the following command will generate an error on the HP 34901A module since channel 122 is for current measurements only CONFigure VOLTage DC 101 122 182 Chapter 5 Remote Interface Reference SCPI Command Summary Scan Measurement Commands see page 226 for more information MEASure TEMPerature TCouple RID FRID THERmistor DEF lt type gt DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt VOLTage DC lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt VOLTage AC lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt RESistance lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt FRESistance lt range gt AUTO MIN MAX DEF lt resolution gt MI AX DEF lt scan_list gt CURRent DC lt range gt
278. ger TIMer lt seconds gt MIN MAX TIMer Set the scan to scan interval in seconds for measurements on the channels in the scan list This command defines the time from the start of one scan sweep to the start of the next sweep You can set the interval to any value between 0 seconds and 359 999 seconds 99 59 59 hours with 1 ms resolution MIN 0 seconds MAX 359 999 seconds The TIM query returns the scan to scan interval in seconds in the form 1 00000000E 01 TRIGger COUNt lt count gt MIN MAX INFinity COUNt Select the number of times that the instrument will sweep through the scan list a sweep is one pass through the scan list When the specified number of sweeps have occurred the scan stops Select a scan count between 1 to 50 000 sweeps or continuous INFinity MIN 1 sweep MAX 50 000 sweeps The COUN query returns the scan count in the form 1 00000000E 01 If you specified a continuous scan count the query command returns 9 90000200E 37 ROUTe CHANnel DELay lt seconds gt lt ch_list gt CHANnel DELay lt ch_list gt Add a delay between multiplexer channels in the scan list useful for high impedance or high capacitance circuits The delay is inserted between the relay closure and the actual measurement on the channel The programmed channel delay overrides the default channel delay that the instrument automatically adds to each channel You can set the
279. ges 19 Chapter 1 Quick Start To Connect Wiring to a Module To Connect Wiring to a Module 1 Remove the module cover 3 Route wiring through strain relief Cable Tie Wrap optional 2 Connect wiring to the screw terminals 20 AWG Typical aoe 6mm 5 Install the module into mainframe 100 Channel Number 20 d 05 205 Slot Channel Wiring Hints e For detailed information on each module refer to the section starting on page 163 e To reduce wear on the internal DMM relays wire like functions on adjacent channels e For information on grounding and shielding see page 335 e The diagrams on the next page show how to connect wiring to a multiplexer module for each measurement function 20 Chapter 1 Quick Start To Connect Wiring to a Module Thermocouple Thermocouple Types B E J K N R S T See page 351 for thermocouple color codes 2 Wire Ohms RTD Thermistor Ranges 100 1 k 10k 100 k 1 M 10 M 100 MQ RTD Types 0 00385 0 00391 Thermistor Types 2 2 k 5k 10k DC Current AC Current Valid only on channels 21 and 22 on the HP 34901A Ranges 10 mA 100 mA 1A DC Voltage AC Voltage Frequency Ranges 100 mV 1 V 10 V 100 V 300 V 4 Wire Ohms RTD o t _ Source LI m o R o H Sense LI QE
280. gh throughput automated test applications Each of the 16 channels switches both HI and LO inputs thus providing fully isolated inputs to the internal multimeter The module is divided into two banks of eight two wire channels each When making four wire resistance measurements channels from Bank A are automatically paired with channels from Bank B You can close multiple channels on this module only if you have not configured any channels to be part of the scan list Otherwise all channels on the module are break before make Es HP 34903A 20 Channel Actuator General Purpose Switch e 300 V 1A actuation and switching e SPDT Form C latching relays e Breadboard area for custom circuits e For detailed information and a module diagram see page 168 Use this module for those applications that require high integrity contacts or quality connections of non multiplexed signals This module can switch 300 V 1 A 50 W maximum switch power to your device under test or to actuate external devices Screw terminals on the module provide access to the Normally Open Normally Closed and Common contacts for each of the 20 switches A breadboard area is provided near the screw terminals to implement custom circuitry such as simple filters snubbers or voltage dividers HP 34904A 4x8 Two Wire Matrix Switch e 32 two wire crosspoints e Any combination of inputs and outputs can be connected at a time e 300 V 1 A switching e For detaile
281. h ch earth dc ac rms 300 V 300 V 300 V 300 V 300 V DC Characteristics Offset Voltage l lt 3uV lt 6uV lt 3uV lt 3uV lt 3uV Initial Closed Channel R M lt 10 lt 10 lt 10 lt 0 20 lt 12 Isolation ch ch ch earth gt 10 GQ gt 10 GQ gt 10 GQ gt 10 GQ gt 10 GQ AC Characteristics Bandwidth 10 MHz 10 MHz 10 MHz 10 MHz 10 MHz Ch Ch Cross Talk dB l 10 MHz 45 45 18 BI 45 33 Capacitance Hito LO lt 50 pF lt 50 pF lt 50 pF lt 10 pF lt 50 pF Capacitance LO to Earth lt 80 pF lt 80 pF lt 80 pF lt 80 pF lt 80 pF Volt Hertz Limit 108 108 108 108 108 Other T C Cold Junction Accuracy typical 0 8 C 0 8 C 0 8 C Switch Life No Load typical 100M 100M 100M 100M 100M Switch Life Rated Load typical 41 100k 100k 100k 100k 100k Temperature Operating All Modules 0 C to 55 C Temperature Storage All Modules 20 C to 70 C Humidity non condensing All Modules 40 C 80 R H 1 Errors included in the DMM measurement accuracy specifications 2 50Q source 502 load 3 Isolation within channel 1 to 20 or 21 to 40 banks is 40 dB 4 Applies to resistive loads only 409 Chapter 9 Specifications Module Specifications HM Module Specifications HP 34905A 34906A RF Multiplexer The ac performance graphs are shown on the following page Gen
282. h the readings using the FORMat READing commands The following is an example of a reading stored in memory with all fields enabled relative time is shown 2 61950000E 01 C 00000000 017 101 2 4 1 Reading with Units 26 195 C 3 Channel Number 2 Time Since Start of Scan 17 ms 4 Alarm Limit Threshold Crossed 0 No Alarm 1 LO 2 Hl DATA POINts Count the total number of readings from all channels in the scan list currently stored in reading memory from a scan Returns a value between 0 and 50 000 readings DATA REMove lt num_rdgs gt Read and erase the specified number of readings from non volatile memory The readings are erased from memory starting with the oldest reading first The purpose of this command is to allow you to periodically remove readings from memory during a scan than would normally cause reading memory to overflow for example during a scan with an infinite scan count The output from this command is affected by the FORM READ commands see Reading Format Commands on page 231 235 Chapter 5 Remote Interface Reference Scanning Overview SYSTem TIME SCAN Read the time at the start of the scan This command is not affected by the FORMat READ TIME TYPE command Returns the time in the form 1997 06 02 18 30 00 000 J une 1 1997 at 6 30 PM FETCh Transfer readings stored in non volatile memory to the instru
283. h_list gt SENSe TOTalize CLEar IMMediate lt ch_list gt SENSe TOTalize DATA lt ch_list gt B This command redefines the scan list when executed Default parameters are shown in bold 194 Chapter 5 Remote Interface Reference SCPI Command Summary Digital Output Commands see page 258 for more information Ch 01 Ch 02 Cho3 Cho4 Chos5 DIO LSB DIO MSB Totalizer DAC DAC SOURce DIGital DATA BYTE WORD lt data gt lt ch_list gt DIGital DATA BYTE WORD lt ch _list gt SOURce DIGital STATe lt ch_list gt DAC Output Commands see page 258 for more information Ch 01 Ch 02 Ch 03 Ch 04 Ch 05 DIO LSB DIO MSB Totalizer DAC DAC SOURce VOLTage lt voltage gt lt ch_list gt VOLTage lt ch_list gt Switch Control Commands see page 259 for more information ROUTe CLOSe lt ch_list gt CLOSe EXCLusive lt ch_list gt CLOSe lt ch_list gt ROUTe OPEN lt ch_list gt OPEN lt ch_list gt ROUTe CHANnel FWIRe OFF ON lt ch_list gt CHANnel FWIRe lt ch_list gt ROUTe DONE SYSTem CPON 100 200 300 ALL Default parameters are shown in bold 195 Chapter 5 Remote Interface Reference SCPI Command Summary Scan Triggering Commands see page 228 for more information TRIGger
284. handler ViStatus _VI_FUNCH SRQ_handler ViSession DataAcqu ViEventType eventType ViEvent context ViAddr userHdlr void main Open communication with DataAcqu using HP IB address 9 viOpenDefaultRM amp defaultR viOpen defaultRM GPIBO 9 INSTR VI_NULL VI_NULL amp DataAcqu Reset ins viPrintf Da Configure trument to power on and clear the Status Byte taAcqu RST CLS n the Status Registers to generate an interrupt whenever an alarm is detected on Alarm 1 or when the operation is complete viPrintf Dat viPrintf Dat STATUS ALARM ENABLE 1 n Enable Alarm 1 ESE 1 n Enable the Operation Complete bit aAcqu aAcqu Enable Status Byte Register bit 1 2 and 5 32 for SRQ viPrintf Dat aAcqu SRE 34 n Enable the interrupt handler for SRQ from the instrument vilInstallHandler DataAcqu VI_EVENT_SERVICE_REQ SRQ_handler viEnableEven Configure ViAddr 10 t DataAcqu VI_LEVENT_SERVICE_REQ VI_HNDLR VI_NULL the instrument to take 10 dc voltage readings on channel 103 Set the alarm and set SRQ if the voltage is greater than 5 volts viPrintf Da viPrintf Da viPrintf Da viPrintf Da viPrintf Da viPrintf Da viPrintf Da viPrintf Da Wait for taAcqu CONF VOLT DC 10 103 n taAcqu TRIG SOURCE TIMER n taAcqu TRIG TIMER 1 n taAcqu TRIG COUNT 10 n taAcqu CALC L
285. have connected the correct interface cable and adapters Even if the cable has the proper connectors for your system the internal wiring may not be correct You can use theHP 34398A Cable Kit to connect the instrument to most computers or terminals e Verify that you have connected the interface cable to the correct serial port on your computer COM1 COM 2 etc 273 Chapter 5 Remote Interface Reference Modem Communications Modem Communications This section gives details on communicating with the instrument from a remote PC using a modem To communicate over the phone lines you must have a PC and two modems One modem is connected to your PC local modem and the other is connected to the HP 34970A remote modem The steps below show how to set up a typical modem 1 2 Connect the remote modem to your local PC Run the Windows Terminal or Hyper Terminal program to configure the modem These programs can be found in the Accessories group Set the baud rate using the Terminal program to the same value used for the HP 34970A For more information on setting the instrument s baud rate refer to Remote Interface Configuration on page 152 Configure the remote modem for auto answer disable command echo and disable result codes Save these settings as the active profile For example when using a Practical Peripherals PM 14400F XMT modem the command string is AT amp F1S0 1EQ1 amp W where AT
286. he instrument e For more information on relay life and load considerations refer to Relay Life and Preventative Maintenance starting on page 399 147 Chapter 4 Features and Functions System Related Operations e Front Panel Operation To read the count on the active channel choose the following item and then turn the knob To read the count on the internal DMM relays turn the knob counterclockwise beyond the lowest numbered channel in the instrument To read the hidden backplane and bank relays turn the knob clockwise beyond the highest numbered channel in the current slot RELAY CYCLES e Remote Interface Operation To read the relay count on either the internal DMM all three relays or the specified module channels send the following commands DIAG DMM CYCLES DIAG RELAY CYCLES 305 399 To clear the count on either the specified internal DMM relay or the specified module channels the instrument must be unsecured send the following commands DIAG DMM CYCLES CLEAR 2 DIAG RELAY CYCLES CLEAR 305 399 148 Chapter 4 Features and Functions System Related Operations SCPI Language Version Query The instrument complies with the rules and conventions of the present version of SCPI Standard Commands for Programmable Instruments You can determine the SCPI version with which the instrument is in compliance by sending a command from the remote interface
287. ication designed to make it easy to use the HP 34970A with your PC for gathering and analyzing measurements Use the software to set up your test acquire and archive measurement data and perform real time display and analysis of your incoming measurements HP BenchLink Data Logger s key functions include the following e Configure measurements on the spreadsheet like Scan Setup page e Display measurements graphically using the real time Data Grid Strip Chart Readout Bar Meter XY Plot and Histogram windows e Add or configure graphics at any time e Use graphical controls to set output voltages close channels output digital values or view alarms e Copy measurement data and graphics to a file or to the Clipboard for use in other applications e Add textual annotation and explanations to measurement results and test reports e Track readings on a single channel through the Monitor toolbar e Enter information into the Event Log automatically or manually while acquiring measurement data or during post scan analysis e Print scan setups event logs and graphics e Communicate with the instrument using HP IB RS 232 modem or LAN using a LAN to HP IB gateway To install the software refer to Installing HP BenchLink Data Logger Software on page 18 To learn more about the software and its capabilities refer to the On Line Help System for HP BenchLink Data Logger The Plug In
288. ide for more information Self test front panel not responding Self test RAM read write Self test A D sync stuck Self test A D slope convergence Self test Cal not able to calibrate rundown gain Self test Cal rundown gain out of range Self test rundown too noisy Self test serial configuration readback Self test DC gain x1 Self test DC gain x10 Self test DC gain x100 Self test Ohms 500 nA source Self test Ohms 5 uA source Self test DC 300V zero Self test Ohms 10 uA source Self test DC current sense Self test Ohms 100 uA source Self test DC high voltage attenuator Self test Ohms 1 mA source Self test AC rms zero Self test AC rms full scale Self test frequency counter Self test not able to calibrate precharge Self test not able to sense line frequency Self test I O processor not responding Self test I O processor self test 314 Chapter 6 Error Messages Calibration Errors Calibration Errors The following errors indicate failures that may occur during a calibration Refer to the HP 34970A Service Guide for more information 701 Cal security disabled by jumper The calibration security feature has been disabled with a jumper inside the instrument When applicable this error will occur at power on to alert you that the instrument is unsecured 702 Cal secured The instrument is secured against calibration 703 Cal invalid secure code You have entered an invalid calibration secur
289. implified input to the internal DMM is shown below Low V HI oo 12 Vdc to _ s Analog to Digital 2 Converter High V o o x1 p gaat sae 1001 oi LE a Ranging X100 lt LO o For input voltages less than 12 Vdc the Low V switch is closed and applies the input signal directly to the input amplifier For higher voltages the High V switch is closed and the signal is attenuated 100 1 before being applied to the input amplifier The input amplifier gain is set to one of three values x1 x10 or x100 to yield a signal in the range of 12 Vdc for the analog to digital converter For the lower voltage ranges the internal DMM s input resistance is essentially that of the input amplifier The input amplifier uses a low bias current less than 50 pA FET input stage yielding an input resistance greater than 10 GQ On the 100V and 300V input ranges the input resistance is determined by the total resistance of the 100 1 divider You can also set the input resistance to 10 MQ by continuously closing the High V switch for more information on dc input resistance see page 113 354 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in DC Voltage Measurements Common Mode Rejection Ideally the internal DMM is completely isolated from earth referenced circuits However there is finite resistance and capacitance between the input LO terminal and earth ground If the in
290. imum reading on channel CALC AVER MIN TIME 305 Time minimum was logged CALC AVER MAX 305 Maximum reading on channel CALC AVER MAX TIME 305 Time maximum was logged CALC AVER AVER 305 Average of all readings on channel CALC AVER COUNT 305 Number of readings taken on channel CALC AVER PTPEAK 305 Peak to peak maximum minimum The following command retrieves the last reading taken on channel 301 during a scan DATA LAST 301 The following command clears the contents of statistics memory for the selected channel CALC AVER CLEAR 305 Use the following command to determine the total number of readings stored in memory all channels from the most recent scan DATA POINTS The following command reads and clears the specified number of readings from memory This allows you to continue a scan without losing data stored in memory if memory becomes full new readings will overwrite the first readings stored The specified number of readings are cleared from memory starting with the oldest reading DATA REMOVE 12 92 Chapter 4 Features and Functions Single Channel Monitoring Single Channel Monitoring In the Monitor function the instrument takes readings as often as it can on a single channel even during a scan This feature is useful for trouble shooting your system before a test or for watching an important signal
291. in allowed is 1E 15 and the maximum offset allowed is 1E 15 e The MEASure and CONFigure commands automatically set the gain M to 1 and offset B to 0 e A Factory Reset RST command turns off scaling and clears the scaling values on all channels An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not clear the scaling values and does not turn off scaling 120 Chapter 4 Features and Functions Mx B Scaling e Front Panel Operation The menu automatically guides you through the gain offset and measurement label settings SET GAIN SET OFFSET SET LABEL Toreset the gain offset and measurement label to their defaults go to the corresponding level in the menu and turn the knob To turn scaling off without clearing the gain and offset values go to the first level in the menu and select SCALING OFF SET GAIN TO 1 SET OFST TO 0 DEFAULT LABEL 4 Tomakea null measurement and store it as the offset go to SET OFFSET in the menu and turn the knob MEAS OFFSET Remote Interface Operation Use the following commands to set the gain offset and custom measurement label CALC SCALE GAIN 1 2 101 CALC SCALE OFFSET 10 101 CALC SCALE UNIT PSI 101 After setting the gain and offset values send the following command to enable the scaling function on the specified chann
292. in when the specified trigger conditions are satisfied following the receipt of the READ command Readings are then sent immediately to the instrument s output buffer You must then enter the readings into your computer or the instrument will stop scanning when the output buffer becomes full Readings are not stored in the instrument s internal memory when using the READ command Note Sending the READ command is like sending the INITiate command followed immediately by the FETCh command except the readings are not stored in reading memory when using READ If you send two query commands without reading the response from the first and then attempt to read the second response you may receive some data from the first response followed by the complete second response To avoid this do not send a query command without first reading the response When you cannot avoid this situation send a Device Clear before sending the second query command Using the INITiate and FETCh Commands The INITiate and FETCh commands provide the lowest level of control with the most flexibility of scan triggering and reading retrieval Use the INITiate command after you have configured the instrument for a scan Scanning will begin when the specified trigger conditions are satisfied following the receipt of the INITiate command The readings are placed in the instrument s internal reading memory up to 50 000 readings can be stored if m
293. ing Query the calibration message and return a quoted string Returns a number in the form CAL 06 01 98 CALibration VALue lt value gt CALibration VALue Specify the value of the known calibration signal as outlined in the calibration procedures in the HP 34970A Service Guide The VAL command reads present calibration value Returns a number in the form 00000000E 01 293 Chapter 5 Remote Interface Reference Service Related Commands Service Related Commands INSTrument DMM OFF ON DMM Disable or enable the internal DMM When you change the state of the internal DMM the instrument issues a Factory Reset RST command The DMM query returns the state of the internal DMM Returns 0 disabled or 1 enabled INSTrument DMM INSTalled Query the instrument to determine if the internal DMM is installed Returns O not installed or 1 installed DIAGnostic DMM CYCLes Query the cycle count of the three relays on the internal DMM These relays are numbered 1 2 and 3 These relays open or close when a function or range is changed on a module Returns three numbers one for each of the three backplane relays DIAGnostic DMM CYCLes CLEar 1 2 3 Reset the relay cycle count on the specified internal DMM relay Note that the instrument must be unsecured to reset the cycle count to unsecure the instrument see the calibration section on page 292
294. input with up to 300 Vdc of bias on any range Crest Factor Maximum 5 1 at Full Scale Additional Crest Factor Errors non sinewave Crest Factor 1 2 0 05 of reading Crest Factor 2 3 0 15 of reading Crest Factor 3 4 0 30 of reading Crest Factor 4 5 0 40 of reading AC Filter Bandwidth Slow 3 Hz 300 kHz Medium 20 Hz 300 kHz Fast 200 Hz 300 kHz Input Impedance Input Protection 1MQ 2 in parallel with 150 pF 300 Vrms on all ranges Frequency and Period Measurement Method Voltage Ranges Reciprocal counting technique Same as AC Voltage function Function Digits BI Readings s AC Filter ACV ACI 61 2 7 sec reading Slow 3 Hz 612 1 Medium 20 Hz 612 g 6l Fast 200 Hz 612 10 Fast 200 Hz 612 100 7 Fast 200 Hz Single Channel Measurement Rates 8 Function Resolution Readings s ACV 61 Slow 3 Hz 0 14 61 2 Medium 20 Hz 1 61 Fast 200 Hz 8 614 I 100 Frequency Period 61 Digits 1s gate 0 77 61 Digits 1s gate 1 512 Digits 100 ms 2 5 51 2 Digits 100 ms J 9 41 Digits 10 ms 3 2 41 Digits 10 ms 11 70 Gate Time 1s 100 ms or 10 ms Measurement Timeout Selectable 3 Hz 20 Hz 200 Hz LF limit True RMS AC Current Measurement Method Direct coupled to the fuse and shunt AC coupled True RMS measurement measures the ac component only 5Q for 10 mA 0 1 for 100 mA 1A 1 5A 250 V fuse on HP 34901A module Shunt Resistance Input Protection
295. instrument The Rear Panel at a Glance a m a 2 1 f 00000 a 4 a 4 Ext Trig Alarms 5V i e p 120 5 s 2 Rin 0 a RS 232 am a l P ppi z Fuso 500mAT l EOS 58 457 jo h oh comeetic end O foreign componente HP 1B Opt 001 J T a 1 Slot Identifier 100 200 300 4 Power Line Fuse Holder Assembly 2 Ext Trig Input Alarm Outputs Channel 5 Power Line Voltage Setting Advance Input Channel Closed Output 6 Chassis Ground Screw 3 RS 232 Interface Connector 7 HP IB IEEE 488 Interface Connector Use the Menu to e Select the HP IB or RS 232 interface see chapter 2 e Set the HP IB address see chapter 2 e Set the RS 232 baud rate parity and flow control mode see chapter 2 WARNING For protection from electrical shock the power cord ground must not be defeated If only a two contact electrical outlet is available connect the instrument s chassis ground screw see above to a good earth ground HP BenchLink Data Logger Software at a Glance HP BenchLink Data Logger is a Windows based appl
296. ion procedures see chapter 4 in the HP 34970A Service Guide CALibration Perform a calibration of the instrument using the specified calibration value CALibration VALue command Before you can calibrate the instrument you must unsecure it by entering the correct security code Returns 0 PASS or 1 FAIL CALibration COUNt Query the instrument to determine the number of times it has been calibrated Note that your instrument was calibrated before it left the factory When you receive your instrument read the count to determine its initial value The calibration count is stored in non volatile memory in the mainframe The calibration count increments up to a maximum of 65 535 after which it rolls over to 0 Since the value increments by one for each calibration point a complete calibration may increase the value by many counts The calibration count is also incremented by calibrations of the DAC channels on the multifunction module CALibration SECure CODE lt new_code gt Enter a new security code To change the security code you must first unsecure the instrument using the old security code and then enter a new code The security code is set to HP034970 when the instrument is shipped from the factory The security code is stored in non volatile memory in the mainframe The security code may contain up to 12 alphanumeric characters The first character must be a letter but the remaining characters ca
297. ion that notifies the HP 34970A to advance to the next channel in the scan list Note that the Channel Advance source shares the same sources as the scan interval However an error is generated if you attempt to set the channel advance source to the same source used for the scan interval e You can specify the number of times the instrument will sweep through the scan list When the specified number of sweeps have occurred the scan stops For more information refer to Scan Count on page 86 96 Chapter 4 Features and Functions Scanning With External Instruments e An externally controlled scan can also include a read of a digital port or a read of the totalizer count on the multifunction module When the channel advance reaches the first digital channel the instrument scans through all of the digital channels in that slot and stores the readings in reading memory only one channel advance signal is required e You can configure the list of channels for 4 wire external scanning without the internal DMM When enabled the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections e Front Panel Operation To select the channel advance source choose from the following items mr AUTO ADVANCE EXT ADVANCE Toinitiate the scan press Ger the SCAN annunciator will turn on To configure the instrument for 4 wire external scanning choose
298. ions of reading of range l Includes measurement error switching error and transducer conversion error Temperature Function Range M Test Current or 24 Hour l 90 Day 1 Year Coefficient C Burden Voltage 23 C 1 C 23 C 5 C 23 C 5 C 0C 18 C 28 C 55 C DC Voltage 100 0000 mV 0 0030 0 0035 0 0040 0 0040 0 0050 0 0040 0 0005 0 0005 1 000000 V 0 0020 0 0006 0 0030 0 0007 0 0040 0 0007 0 0005 0 0001 10 00000 V 0 0015 0 0004 0 0020 0 0005 0 0035 0 0005 0 0005 0 0001 100 0000 V 0 0020 0 0006 0 0035 0 0006 0 0045 0 0006 0 0005 0 0001 300 000 V 0 0020 0 0020 0 0035 0 0030 0 0045 0 0030 0 0005 0 0003 Resistance 4 100 0000 Q 1 mA current source 0 0030 0 0035 0 008 0 004 0 010 0 004 0 0006 0 0005 1 000000 kQ 1mA 0 0020 0 0006 0 008 0 001 0 010 0 001 0 0006 0 0001 10 00000 kQ 100 uA 0 0020 0 0005 0 008 0 001 0 010 0 001 0 0006 0 0001 100 0000 kQ 10 pA 0 0020 0 0005 0 008 0 001 0 010 0 001 0 0006 0 0001 1 000000 MQ 5pA 0 002 0 001 0 008 0 001 0 010 0 001 0 0010 0 0002 10 00000 MQ 500 nA 0 015 0 001 0 020 0 001 0 040 0 001 0 0030 0 0004 100 0000 MQ 500 nA 10 MQ 0 300 0 010 0 800 0 010 0 800 0 010 0 1500 0 0002 DC Current 10 00000 mA lt 0 1 V burden 0 005 0 010 0 030 0 020 0 050 0 020 0 002 0 0020 HP 34901A Only 100 0000 mA lt 0 6V 0 010 0 004 0 030 0 005 0 050 0 005 0 00
299. iplexers starting on page 172 e HP 34907A Multifunction Module starting on page 174 e HP 34908A 40 Channe Single Ended Multiplexer starting on page 176 163 Chapter 4 Features and Functions HP 34901A 20 Channel Multiplexer HP 34901A 20 Channe Multiplexer This module is divided into two banks of 10 channels each Two additional fused channel s are available for making direct calibrated dc or ac current measurements with the internal DMM external shunts are not required All 22 channels switch both HI and LO inputs thus providing fully isolated inputs to the internal DMM or an external instrument When making 4 wire resistance measurements the instrument automatically pairs channel n with channe n 10 to provide the source and sense connections The module has a built in isothermal block to minimize errors due to thermal gradients when measuring thermocouples Backplane Switches Channel Switches Internal J z f Ts OH ol DMM Input o o 1 r sae L 98 8 2H gi 10 O H a Com Reference A g g Junction lt 17 A a Bank Switch Sensor y l Ou 5 a Com 4W Sense SH SL 11 Internal H o go QH DMM Input lt 1 we gt 20 4W Sense 97 Shunt Switches 95 2 21 puse ot 9 SL 21 DMM input lt ee eee Current Channels Current S 96 a ba Fuse Se 22 Q OQ Com Current NOTES e Only one of channels 21 and 22 can be connected
300. ired multiplexer or digital channels Channels which are not in the scan list are skipped during the scan The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300 Measurements are taken only during a scan and only on those channels which are included in the scan list The Sample annunciator turns on during each measurement e You can store up to 50 000 readings in non volatile memory during a scan Readings are stored only during a scan and all readings are automatically time stamped If memory overflows the MEM annundator will turn on a status register bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved You can read the contents of memory at any time even during a scan Reading memory is not cleared when you read it e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan Therefore the contents of memory are always from the most recent scan e Ifyou abort a scan that is running the instrument will complete the one measurement in progress the entire scan will not be completed and the scan will stop You cannot resume the scan from where it left off If you initiate a new scan all readings are deared from memory 226 Chapter 5 Remote Interface Reference Scanning Overview e You can use either the internal DMM or an extern
301. is configuration you must set up a scan list to indude all desired multiplexer or digital channels Channels which are not in the list are skipped during the scan The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300 For an externally controlled scan you must either remove the internal DMM from the HP 34970A or disable it see Internal DMM Disable on page 145 Since the internal DMM is not used readings from multiplexer channels are not stored in internal reading memory External connections are required to synchronize the scan sequence between the HP 34970A and the external instrument The HP 34970A must notify the external instrument when a relay is closed and settled including channel delay The HP 34970A outputs a Channel Closed pulse from pin 5 on the rear panel connector see previous page In response the external instrument must notify the HP 34970A when it has finished its measurement and is ready to advance to the next channel in the scan list The HP 34970A accepts a Channel Advance signal on the External Trigger input line pin 6 e You can configure the event or action that controls the onset of each sweep through the scan list a sweep is one pass through the scan list When the internal DMM is removed or disabled the default scan interval source is timer For more information refer to Scan Interval on page 80 e You can configure the event or act
302. is second thermocouple affects the voltage measurement of the T type thermocouple If the temperature of the thermocouple created at J2 the LO input terminal is known the temperature of the T type thermocouple can be calculated One way to do this is to connect two T type thermocouples together to create only copper to copper connections at the internal DMWM s input terminals and to hold the second thermocouple at a known temperature 347 Chapter 8 Tutorial Measurement Fundamentals An ice bath is used to create a known reference temperature 0 C Once the reference temperature and thermocouple type are known the temperature of the measurement thermocouple can be calculated Internal DMM J2 Cu O Cu Ice Bath The T type thermocouple is a unique case since one of the conductors copper is the same metal as the internal DMM s input terminals If another type of thermocouple is used two additional thermocouples are created For example take a look at the connections with a J type thermocouple iron and constantan Internal DMM J1 Cu ot Fe Cu a Fe J1 c a done Cc Cu oe F C i Cu Fe x J2 Ice Bath Two additional thermocouples have been created where the iron Fe lead connects to the internal DMM s copper Cu input terminals Since these two junctions will generate opposing voltages their effect will be to cancel each other However if the input terminals are
303. istance in humid conditions The table below shows several common insulating materials and their typical resistances Insulating Material Resistance Range Moisture Absorbing Teflon PTFE Nylon PVC Polystyrene Ceramic Glass Epoxy FR 4 G 10 Phenolic Paper 1 Tato 1 Pa 1 Gato 10 Ta 10 Gato 10 Ta 100 Ga to 1 Pa 1 Gato 1 Pa 1 Gato 10 Ta 10 Ma to 10 Ga lt lt ZZ lt lt zZ 372 Chapter 8 Tutorial Measurement Fundamentals Strain Gage Measurements Although the instrument does not directly support strain measurements you can measure a strain gage using a 4 wire resistance measurement with scaling However HP BenchLink Data Logger software has built in strain gage measurement capability When a force is applied to a body the body deforms The deformation per unit length is called strain e Strain may be either tensile or compressive Practical strain values are usually quite small typically less than 0 005 inch inch for most metals and are often expressed in micro strains ue There are three common types of strain measurements as shown below Force Force i F F Normal Strain e is a measure 4m ofthe deformation along the axis saand of the applied force e AL L L AL Shearing Strain y is ameasure of the angular distortion of a body It is approximated by the tangent of the angle formed by l the angular change between two line segments
304. itioning section typically comprising switching ranging and amplification circuitry If the input signal is a dc voltage the signal conditioner is composed of an attenuator for the higher input voltages and a dc amplifier for the lower input voltages If the input signal is an ac voltage a converter is used to convert the ac signal to its equivalent dc value true RMS value Resistance measurements are performed by supplying a known de current to an unknown resistance and measuring the dc voltage drop across the resistor The input signal switching and ranging circuitry together with the amplifier circuitry convert the input to a de voltage which is within the measuring range of the internal DMM s analog to digital converter ADC You can allow the instrument to automatically select the measurement range using autoranging or you can select a fixed measurement range using manual ranging Autoranging is convenient because the instrument automatically decides which range to use for each measurement based on the input signal For fastest scanning operation use manual ranging for each measurement some additional time is required for autoranging since the instrument has to make a range selection Analog to Digital Conversion ADC The ADC takes a prescaled dc voltage from the signal conditioning circuitry and converts it to digital data for output and display on the front panel The ADC governs some of the most basic measurement charac
305. ity code You must use the same security code to unsecure the instrument that was used to secure it and vice versa The security code may contain up to 12 alphanumeric characters The first character must be a letter but the remaining characters can be letters numbers or an underscore _ You do not have to use all 12 characters but the first character must always be a letter The security code is set to HP034970 when the instrument is shipped from the factory 704 Cal secure code too long The security code may contain up to 12 alphanumeric characters A security code was received which contained more than 12 characters 705 Cal aborted A calibration in progress is aborted when you turn off the instrument or send a bus Device Clear 706 Cal value out of range The specified calibration value CALibration VALue is not valid for the present measurement function and range 707 Cal signal measurement out of range The specified calibration value CALibrat ion VALue does not match the signal applied to the instrument 708 Cal signal frequency out of range The input signal frequency for an ac calibration does not match the required input frequency for this calibration 709 Cal no cal for this function or range You cannot perform calibrations for most ac current ranges the 100 MQ resistance range and period 315 710 720 721 722 723 724 725 730 731 732 733 734 735 736 740 741 742 743 744 74
306. izer channel These channels do not have to be part of the scan list to generate an alarm Alarms are evaluated continuously as soon as you enable them For more information see Using Alarms With the Multifunction Module on page 130 e You can monitor a totalizer channel even if the channel is not part of the scan list the internal DMM is not required either The count on a totalizer channel is not reset when it is being monitored the Monitor ignores the totalizer reset mode e A Factory Reset RST command Instrument Preset SySTem PRESet command and Card Reset SySTem CPON command reset the count to g e Front Panel Operation After selecting the totalizer press to read the count If you have selected the READ RESET mode the count is reset each time it is read The count is displayed until you press another key turn the knob or until the display times out To configure the totalizer reset mode choose from the following items READ READ RESET To configure the totalizer to count on the falling edge or rising edge of the input signal choose from the following items COUNT FALLING COUNT RISING To add a totalizer read to a scan list choose the following item TOT READ 136 Chapter 4 Features and Functions Totalizer Operations e Remote Interface Operation To read the count from the specified totalizer channel send the following command The count m
307. kel Chromium Silicon Nisil Nickel Silicone Magnesium N A Not Available 351 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in Thermocouple Measurements Reference Junction Error A thermocouple is typically formed by welding or soldering two wires together to make the junction Soldering introduces a third metal into the junction Provided that both sides of the thermocouple are at the same temperature the third metal has little effect Commercial thermocouples are welded using a capacitive discharge technique This technique is used to prevent overheating of the thermocouple wire near the junction and to prevent the diffusion of the welding gas and atmosphere into the thermocouple wire A poor weld or bad solder connection can also cause errors in a thermocouple measurement Open thermocouple junctions can be detected by checking the resistance of the thermocouple A resistance measurement of more than 5 KQ typically indicates a defective thermocouple The HP 34970A contains a built in automatic thermocouple check feature If you enable this feature the instrument measures the channel resistance after each thermocouple measurement to ensure a proper connection For more information on using the thermocouple check feature see page 107 Diffusion Error Diffusion in a thermocouple wire is the process of changing the alloy type along the wire itself Atmospheric particles can actually diffuse into the metal These
308. l overwrite the first readings stored Readings are stored in memory until you are able to retrieve them Use the FETCh command to retrieve reading results READ Change the state of the triggering system from the idle state to the wait for trigger state Scanning will begin when the specified trigger conditions are satisfied following the receipt of the READ command Readings are then sent immediately to the instrument s output buffer You must then enter the readings into your computer or the instrument will stop scanning when the output buffer becomes full Readings are not stored in the instrument s internal memory when using READ TRG Trigger the instrument from the remote interface 230 Chapter 5 Remote Interface Reference Scanning Overview Reading Format Commands During a scan the instrument automatically adds a time stamp to all readings and stores them in non volatile memory Each reading is stored with measurement units time stamp channel number and alarm status information You can specify which information you want returned with the readings from the front panel all of the information is available for viewing The reading format applies to all readings being removed from the instrument from a scan you cannot set the format on a per channe basis The following is an example of a reading stored in memory with all fields enabled relative time is shown 2 61950000E 01 C 0000
309. l be allowed before terminating the scan You can store up to 50 000 readings in non volatile memory during a scan If you set a continuous scan and memory overflows the MEM annunciator will turn on a status register bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved The MEASure and CONFigure commands automatically set the scan count to 1 From the front panel a Factory Reset Sto Rci menu sets the scan count to continuous From the remote interface a Factory Reset RST command sets the scan count to 1 sweep Front Panel Operation ry 00020 SCANS The default is CONTINUOUS To set the count to a value between 1 and 50 000 scans turn the knob clockwise and enter a number Remote Interface Operation TRIG COUNT 20 Note Toconfigure a continuous scan send TRIG COUNT INFINITY 86 Chapter 4 Features and Functions Scanning Reading Format During a scan the instrument automatically adds a time stamp to all readings and stores them in non volatile memory Each reading is stored with measurement units time stamp channel number and alarm status information F rom the remote interface you can specify which information you want returned with the readings from the front panel all of the information is available for viewing The reading format applies to all readings being removed from the instrument from a scan you cannot set the format on a
310. l since these waveforms do not contain a dc offset Non symmetrical waveforms such as pulse trains contain dc voltages which are rejected by ac coupled true RMS measurements An ac coupled true RMS measurement is desirable in situations where you are measuring small ac signals in the presence of large dc offsets For example this situation is common when measuring ac ripple present on dc power supplies There are situations however where you might want to know the ac dc true RMS value You can determine this value by combining results from de and ac measurements as shown below You should perform the dc measurement using at least 10 power line cycles of integration 6 digit mode for best ac rejection ac dc V ac dc2 360 Chapter 8 Tutorial Measurement Fundamentals Making High Speed AC Measurements The internal DMM s ac voltage and ac current functions implement three low frequency filters These filters allow you to trade off low frequency accuracy for faster scanning speed The fast filter settles in 0 12 seconds and is useful for measurements above 200 Hz The medium filter settles in 1 second and is useful for measurements above 20 Hz The slow filter settles in 7 seconds and is useful for measurements above 3 Hz With a few precautions you can perform ac measurements at speeds up to 100 readings per second use manual ranging to eliminate autoranging delays By setting the preprogrammed channel settling delays to zero
311. le noise immunity Teflon is a registered trademark of E I duPont deNemours and Company 55 Chapter 3 System Overview Data Acquisition System Overview Transducers and Sensors Transducers and sensors convert a physical quantity into an electrical quantity The electrical quantity is measured and the result is then converted to engineering units For example when measuring a thermocouple the instrument measures a dc voltage and mathematically converts it to a corresponding temperature in C F or K Measurement Typical Transducer Types Typical Transducer Output Temperature Thermocouple 0 mV to 80 mV RTD 2 wire or 4 wire resistance from 5Q to 500 Thermistor 2 wire resistance from 102 to 1 MQ Pressure Solid State 10 Vdc Flow Rotary Type 4 mA to 20 mA Thermal Type Strain Resistive Elements 4 wire resistance from 10Q to 10 kQ Events Limit Switches OV or 5V Pulse Train Optical Counters Rotary Encoder Digital System Status TTL Levels Alarm Limits The HP 34970A has four alarm outputs which you can configure to alert you when a reading exceeds specified limits on a channel during a scan You can assign a high limit a low limit or both to any configured channel in the scan list You can assign multiple channels to any of the four available alarms numbered 1 through 4 For example you can configure the instrument to generate an alarm on Alarm 1 when a limit is exce
312. le starting on page 392 e Relay Life and Preventative Maintenance starting on page 399 334 Chapter 8 Tutorial System Cabling and Connections System Cabling and Connections This section describes methods to reduce measurement errors that can be introduced by your system cabling Many system cabling errors can be reduced or eliminated by selecting the proper cable and grounding scheme for your system Cable Specifications A wide variety of general purpose and custom cables are available The following factors influence the type of cable that you choose e Signal Requirements such as voltage frequency accuracy and measurement speed e Interconnection Requirements such as wire sizes cable lengths and cable routing e Maintenance Requirements such as intermediate connectors cable terminations strain relief cable lengths and cable routing Cables are specified in a variety of ways Be sure to check the following specifications for the cable type you intend to use continued on the following page e Nominal Impedance insulation resistance Varies with the frequency of the input signal Check for HI to LO channel to channel and HI or LO to shield High frequency RF applications have exact requirements for cable impedance e Dielectric Withstand Voltage Must be high enough for your application WARNING To prevent electrical shock or equipment damage insulate all channels to the highe
313. le offers simple on off switching which you can use to control power devices or for custom switching applications For example you can use an actuator to build a simple resistance ladder as shown below Resistance Out Actuator 100 J o COM J QNO lt lt 100 oo 2 COM lt NO lt gt 5 102 COM lt o NO lt gt 102 o COM lt NO lt gt 5 102 COM lt I NO lt 100 re lol NO Normally Open In the above diagram the resistance is 602 when all of the actuator channels are open not connected to COM Note that when the actuator channels are open as shown above the normally closed contacts not shown above are connected to COM Values from 102 to 50Q are selected by closing the appropriate channel s on the module 384 Chapter 8 Tutorial Actuators and General Purpose Switching Snubber Circuits Whenever a relay contact opens or closes electrical breakdown or arching can occur between the contacts This can cause high frequency noise radiation voltage and current surges and physical damage to the relay contacts A breadboard area is provided on the HP 34903A to implement custom circuitry such as simple filters snubbers and voltage dividers The breadboard area provides the space necessary to insert your own components but there are no circuit board traces here You can build these networks to provide contact protection when actuating ac power line for
314. lect the thermocouple type for the active channel choose the following item J TYPE T C To enable the thermocouple check feature on the active channel opens are reported as OPEN T C choose the following item T C CHECK ON To select the reference junction source for the active channel choose one of the following items INTERNAL REF EXTERNAL REF FIXED REE Note Before selecting an external source be sure to configure channel 01 in the lowest slot for a thermistor or RTD measurement 108 Chapter 4 Features and Functions Temperature Measurement Configuration e Remote Interface Operation You can use the MEASure or CONF igure command to select the probe type and thermocouple type For example the following statement configures channel 301 for a J type thermocouple measurement CONF TEMP TC J 301 You can also use the SENSe command to select the probe type and thermocouple type For example the following statement configures channel 203 for a J type thermocouple measurement SENS TEMP TRAN TC TYPE J 203 The following statements use the SENSe command to set a fixed reference junction temperature of 40 degrees always in C on channel 203 SENS TEMP TRAN TC RJUN TYPE FIXED 203 SENS TEMP TRAN TC RJUN 40 203 The following statement enables the thermocouple check featu
315. led at a time The earth referenced section also provides four hardware alarm outputs and external trigger lines You can use the alarm output lines to trigger external alarm lights sirens or send a TTL pulse to your control system The floating section contains the main system processor and controls all of the basic functionality of the instrument This is where the instrument communicates with the plug in modules scans the keyboard controls the front panel display and controls the internal DMM The floating section also performs Mx B scaling monitors alarm conditions converts transducer measurements to engineering units time stamps scanned measurements and stores data in non volatile memory 53 Chapter 3 System Overview Data Acquisition System Overview Plug In Modules The HP 34970A offers a complete selection of plug in modules to give you high quality measurement switching and control capabilities The plug in modules communicate with the floating logic via the internal isolated digital bus The multiplexer modules also connect to the internal DMM via the internal analog bus Each module has its own microprocessor to offload the mainframe processor and minimize backplane communications for faster throughput The table below shows some common uses for each plug in module For more information on each module refer to the module sections in chapter 4 starting on page 163 Model Number Module Name Common Uses
316. ll read data from both ports simultaneously with the same time stamp This will allow you to externally combine the two 8 bit value into one 16 bit value SENSe DIGital DATA BYTE WORD lt ch_list gt Read an 8 bit byte or a 16 bit word digital pattern from the specified digital input channels If you are going to read both ports simultaneously WORD you must send the command to port 01 LSB and neither port can be included in the scan list The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot number The output from this command is affected by the FORMat READing commands see Reading Format Commands on page 231 255 Chapter 5 Remote Interface Reference Totalizer Commands Totalizer Commands See also Totalizer Operations in chapter 4 starting on page 135 MEASure TOTalize READ RRESet lt scan_list gt Configure the instrument to read the count on the specified totalizer channels on the multifunction module and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory The totalizer channel is numbered s03 where s represents the slot number To read the totalizer during the scan without resetting the count select the READ parameter To read the totalizer during the scan a
317. ltiplexer module SENSe FUNCtion lt function gt lt ch_list gt Select the measurement function on the specified channels The function name must be enclosed in quotes in the command string for example FUNC VOLT DC Spedfy one of the following strings to set the function TEMPerature CURRent DC VOLTage DC CURRent AC VOLTage AC FREQuency RESistance PERiod FRESistance e Notethat when you change the measurement function on a channel all of the other measurement attributes range resolution etc are set to their default values e You cannot set any function specific measurement attributes unless the channel is already configured for that function For example you cannot set the ac filter unless that channel is already configured for ac voltage or ac current measurements SENSe FUNCtion lt ch_list gt Query the measurement function on the specified channels and return a quoted string The short form of the function name is always returned for example VOLT 214 Chapter 5 Remote Interface Reference Setting the Function Range and Resolution SENSe VOLTage DC RANGe lt range gt MIN MAX lt ch_list gt VOLTage AC RANGe lt range gt MIN MAX lt ch_list gt RESistance RANGe lt range gt MIN MAX lt ch_list gt FRESistance RANGe lt range gt MIN MAX lt ch_list gt CURRent DC RANGe lt range gt MIN MAX lt ch_list gt CURRent
318. matic 170 wiring log 171 HP 34905A module 50Q ac performance graphs 411 channel numbering 172 description 172 390 module overview 8 172 module specifications 410 screw terminal diagram 173 simplified schematic 172 wiring log 173 HP 34906A module 759 ac performance graphs 411 channel numbering 172 description 172 390 module overview 8 172 module specifications 410 screw terminal diagram 173 simplified schematic 172 wiring log 173 HP 34907A module 8 bit vs 16 bit operations 133 138 ac vs TTL threshold 135 adding to scan 133 136 binary format 42 133 channel numbering 174 clearing the count totalizer 136 current limitations DAC 139 397 decimal format 42 133 description 174 driving microwave switches 394 gate signal 135 maximum totalizer count 136 screw terminal diagram 175 simplified block diagrams 174 specifications 412 Totalize Threshold jumper 135 175 totalizer reset mode 136 using alarms 130 wiring log 175 425 Index HP 34908A module channel numbering 176 description 176 screw terminal diagram 177 simplified schematic 176 177 wiring log 177 module overview 9 176 module specifications 409 HP 34970A block diagram 53 dimensions 413 firmware revision 146 HP E2050A LAN to HP IB 51 HP IB IEEE 488 address selection 46 151 cable 51 connector 5 interface selection 46 151 setting address 150 factory address set
319. mber of external pulses the instrument will accept before terminating the scan See Scan Count on page 86 for more information e ftheinstrument receives an external trigger before it is ready to accept one it will buffer one trigger before generating an error e All readings from the scan are stored in non volatile memory Readings accumulate in memory until the scan is terminated until the scan count is reached or until you abort the scan e Mx scaling and alarm limits are applied to measurements during the scan and all data is stored in non volatile memory e Front Panel Operation Interval EXTERNAL SCAN Toinitiate the scan press The EXT annunciator turns on as a reminder that an External Scan is in progress When a TTL pulseis received the scan starts and readings are stored in memory To stop a scan press and hold e Remote Interface Operation The following program segment configures the instrument for an External Scan TRIG SOURCE EXT Select the external trigger configuration TRIG COUNT 2 Sweep the scan list 2 times INIT Initiate the scan Note To stop a scan send the ABORt command 83 Chapter 4 Features and Functions Scanning Scanning on Alarm n this configuration the instrument sweeps the scan list once each time a reading crossing an alarm limit on a channel You can also assign alarms to channels on the multifunction module For example you can generate
320. mber of readings stored points Val getScpi Loop Until points gt 1 Remove one reading at a time from memory For I 1 To numberMeasurements SendSCPI DATA REMOVE 1 Request 1 reading from memory Cellsi l p Iy I The reading number Cells I 3 2 Val getScpi The reading value Do Wait for instrument to put another reading in memory SendSCPI DATA POINTS Get the number of readings stored points Val getScpi Loop Until points gt 1 Or I gt numberMeasurements Next I ClosePort Close communications on HP IB End Sub 322 Chapter 7 Application Programs Example Programs for Excel 7 0 Excel 7 0 Example Port Configuration Macro Option Explicit Declarations for VISA DLL Basic I O Operations Private Declare Function viOpenDefaultRM Lib VISA32 DLL Alias 141 sesn As Long As Long Private Declare Function viOpen Lib VISA32 DLL Alias 131 ByVal sesn As Long _ ByVal desc As String ByVal mode As Long ByVal TimeOut As Long vi As Long As Long Private Declare Function viClose Lib VISA32 DLL Alias 132 ByVal vi As Long As Long Private Declare Function viRead Lib VISA32 DLL Alias 256 ByVal vi As Long ByVal Buffer As String ByVal Count As Long retCount As Long As Long Private Declare Function viWrite Lib VISA32 DLL Alias 257 ByVal vi As Long ByVal Buffer As String ByVal Count As Long retCount As Long As Long Error Codes Glob
321. me measurement resolution number of digits and number of bits Integration Time Resolution Digits Bits 0 02 PLC lt 0 0001 x Range 4 Digits 15 0 2 PLC lt 0 00001 x Range 5 Digits 18 1 PLC lt 0 000003 x Range 5 Digits 20 2 PLC lt 0 0000022 x Range 61 Digits 21 10 PLC lt 0 000001 x Range 61 Digits 24 20 PLC lt 0 0000008 x Range 61 Digits 25 100 PLC lt 0 0000003 x Range 6 Digits 26 200 PLC lt 0 00000022 x Range 6 Digits 26 103 Chapter 4 Features and Functions General Measurement Configuration e Theinstrument selects 1 PLC when the measurement function is changed and after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the integration time setting e Front Panel Operation First select the measurement function on the active channel Then go to the Advanced menu and select one of the choices in PLCs for the active channel INTEG 2 PLC To select the aperture time select INTEGRATE T from the Advanced menu and then specify a value in seconds for the active channel INTEGRATE T e Remote Interface Operation You can set the integration time using the SENSe commands F or example the following statement specifies an integration time of 10 PLC for dc voltage measurements on channel 301 SENS VOLT DC NPLC 10 301 You can also select an aperture time using the SENS
322. ment s output buffer where you can read them into your computer The readings are not erased from memory when you read then using FETCh The output from this command is affected by the FORMat READing commands see Reading Format Commands on page 231 R lt max_count gt Read and erase all readings from reading memory up to max_count The readings are erased from memory starting with the oldest reading This is a special version of the DATA REMove command with faster execution time If you omit the optional max_count parameter the command will read and erase up to 50 0000 readings from memory The output from this command is affected by the FORMat READing commands see Reading Format Commands on page 231 This command returns a series of readings in SCPI definite length block format The response begins with the character followed by a single character representing the number of succeeding characters to interpret as a length specifier followed by a length specifier representing the number of bytes in the block followed by a block of that many bytes For example the R command will return a string similar to the following two readings are shown 231 2 61400000E 01 2 62400000E 01 236 Chapter 5 Remote Interface Reference Single Channel Monitoring Overview Single Channel Monitoring Overview In the Monitor function the instrument takes readings as often as it can on a single
323. ment decides which range to use for each measurement based on the input signal For fastest scanning operation use manual ranging on each measurement some additional time is required for autoranging since the instrument has to make a range selection e Autorange thresholds Down range at lt 10 of range Uprange at gt 120 of range e If theinput signal is greater than can be measured on the selected range the instrument gives an overload indication tOVLD from the front panel or 9 90000000E 37 from the remote interface e For a complete list of the measurement ranges available for each function refer to the instrument specifications in chapter 9 e For temperature measurements the instrument internally selects the range you cannot select which range is used For thermocouple measurements the instrument internally selects the 100 mV range For thermistor and RTD measurements the instrument autoranges to the correct range for the transducer resistance measurement 98 Chapter 4 Features and Functions General Measurement Configuration e For frequency and period measurements the instrument uses one range for all inputs between 3 Hz and 300 kHz Therange parameter is required only to specify the resolution Therefore it is not necessary to send a new command for each new frequency to be measured e The MEASure and CONFigure commands contain an optional range parameter which allows you to specify the rang
324. ment in the wait for trigger state The READ command places the instrument in the wait for trigger state scans the channel once when the Ext Trig terminal is pulsed on the rear panel and sends the reading to the instrument s output buffer CONF VOLT DC 10 0 003 301 TRIG SOUR EXT READ 205 Chapter 5 Remote Interface Reference Simplified Programming Overview Example Using CONFigure With INITiate and FETCh The following program segment is similar to the previous example but it uses INITiate to place theinstrument in the wait for trigger state The INITiate command places the instrument in the wait for trigger state scans the specified channel when the Ext Trig terminal is pulsed on the rear panel and sends the reading to reading memory The FETCh command transfers the reading from reading memory to the instrument s output buffer CONF VOLT DC 10 0 003 301 TRIG SOUR EXT INIT FETC Storing readings in memory using the INITiate command is faster than sending readings to the output buffer using the READ command The INITiate command is also an overlapped command This means that after executing the INITiate command you can send other commands that do not affect the scan Note that the FETCh command will wait until the scan is complete to terminate The instrument can store up to 50 000 readings in internal reading memory Note To stop a sc
325. meters 413 Chapter 9 Specifications To Calculate Total Measurement Error To Calculate Total Measurement Error Each specification includes correction factors which account for errors present due to operational limitations of the internal DMM This section explains these errors and shows how to apply them to your measurements Refer to Interpreting Internal DMM Specifications starting on page 416 to get a better understanding of the terminology used and to help you interpret the internal DMM s specifications The internal DMM s accuracy specifications are expressed in the form of reading of range In addition to the reading error and range error you may need to add additional errors for certain operating conditions Check the list below to make sure you include all measurement errors for a given function Also make sure you apply the conditions as described in the footnotes on the specification pages e Ifyou are operating the internal DMM outside the 23 C 5 C temperature range specified apply an additional temperature coefficient error e For dc voltage de current and resistance measurements you may need to apply an additional reading speed error e For ac voltage and ac current measurements you may need to apply an additional low frequency error or crest factor error Understanding the of reading Error The reading error compensates for inaccuracies that result from the function
326. method is used in systems where lead resistances can become quite large and variable and in automated test applications where cable lengths can be quite long The 4 wire ohms method has the obvious disadvantage of requiring twice as many switches and twice as many wires as the 2 wire method The 4 wire ohms method is used almost exclusively for measuring lower resistance values in any application especially for values less than 10Q and for high accuracy requirements such as RTD temperature transducers Hl Source O Hl Sense O R Vmeter ltest LO Sense O l i O LO Source 370 Chapter 8 Tutorial Measurement Fundamentals Offset Compensation Most connections in a system use materials that produce small dc voltages due to dissimilar metal to metal contact thermocouple effect or electrochemical batteries for a description of the thermocouple effect see page 340 These dc voltages also add errors to resistance measurements The offset compensated measurement is designed to allow resistance measurements in the presence of small dc voltages Offset compensation makes two measurements on the circuit connected to the input channel The first measurement is a conventional resistance measurement The second is the same except the internal DMM s test current source is turned off essentially a normal de voltage measurement The second measurement is subtracted
327. mmand buffer overflow Module reported command syntax error Module reported nonvolatile memory fault Module reported temperature sensor fault Module reported firmware defect Module reported incorrect firmware installed 317 Application Programs Application Programs This chapter contains several example programs to help you develop programs for your specific measurement application Chapter 5 Remote Interface Reference starting on page 179 lists the syntax for the SCPI Standard Commands for Programmable Instruments commands available to program the HP 34970A The examples in this chapter have been tested on a PC running on Windows 95 The examples are written for use over the HP IB interface and require a VISA Virtual Instrument Software Architecture library for use with your HP IB interface card in your PC You will want to make sure that you have the visa32 dll file in your c windows system directory for the examples to work properly Note The HP IB IEEE 488 address is set to 09 when the instrument is shipped from the factory The examples in this chapter assume an HP IB address of 09 320 Chapter 7 Application Programs Example Programs for Excel 7 0 Example Programs for Excel 7 0 This section contains two example programs written using Excel macros Visual Basic for Applications to control the HP 34970A Using Excel you can send SCPI commands to configure the instrument and the
328. mp scanList Select the list of channels to scan SendSCPI ROUTE SCAN SIZE Query the number of channels in scan list and numberChannels Val GetSCPI set variable equal to number of channels SendSCPI FORMAT READING CHAN ON Return channel number with each reading SendSCPI FORMAT READING TIME ON Return time stamp with each reading Set the delay in seconds between relay closure and measurement SendSCPI ROUT CHAN DELAY amp Str channelDelay amp amp scanList Continued on next page 325 Chapter 7 Application Programs Example Programs for Excel 7 0 Set up the scan trigger parameters after configuring the channels in the scan list using the CONFigure command The following commands configure the scan interval SendSCPI TRIG COUNT amp Str numberScans SendSCPI TRIG SOUR TIMER SendSCPI TRIG TIMER amp Str ScanInterval Cells 2 1 Start Time Put headings on spreadshee Cells 4 1 Channel Put headings on spreadshee ct ct Start the scan and retrieve the scan start time SendSCPI INIT SYSTEM TIME SCAN replyString GetSCPI Put time into string variable Convert the time to Excel format and put into cells B2 and C2 Cells 2 2 ConvertTime replyString Cells 2 3 Cells 2 2 Cells 2 3 NumberFormat d mmm yy Format for date Cells 2 2 NumberFormat hh mm ss Format for time
329. n record measurement data on the Excel spreadsheet To write an Excel macro you must first open a module in Excel Go to the Insert menu choose Macro and then Module Name this module Send Commands by clicking on the tab with the right mouse button Create another module and name it Port Configuration You will use the Port Configuration module to configure all of the overhead required to communicate with the instrument over the interface You will use the Send Commands module to send the SCPI commands to the instrument using the Port Configuration module Two Excel examples are included in this section To enter the first example takeReadings type the text as shown on page 322 into the Send Commands module Then type the text for configuring the interface as shown on page 323 into the Port Configuration module After entering the information for both modules go to a spreadsheet and run the example program Note that you must run the macro from a spreadsheet With the cursor in the spreadsheet select Macro from the Tools menu Then double click on the takeReadings macro in the Macro dialog box To run the second example ScanChannels type the text as shown on page 325 into the Send Commands module and reuse the Port Configuration module from the first example page 323 Make any changes necessary to suit your application in the Send Commands module You mu
330. n Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the setting e Front Panel Operation First select the frequency function on the active channel Then go to the Advanced menu and select the slow timeout 3 Hz medium timeout 20 Hz or fast timeout 200 Hz for the active channel The default is the medium timeout value LF 3 HZ SLOW Remote Interface Operation Specify the lowest frequency expected in the input signal on the specified channels The instrument selects the appropriate timeout based on the frequency you specify see table above The MEASure and CONFigure commands automatically select the 20 Hz medium timeout SENS FREQ RANG LOW 3 203 Select the slow timeout 3 Hz 118 Chapter 4 Features and Functions Mx B Scaling Mx Scaling The scaling function allows you to apply a gain and offset to all readings on a specified multiplexer channel during a scan In addition to setting the gain M and offset B values you can also specify a custom measurement label for your scaled readings RPM PSI etc You can apply scaling to any multiplexer channels and for any measurement function Scaling is not allowed with any of the digital channels on the multifunction module e Scaling is applied using the following equation Scaled Reading Gain x Measurement Offset e You must configure the channel function transducer typ
331. n absolute time format and is not affected by the FORMat READing TIME TYPE command setting e You must configure the channel function transducer type etc before setting any alarm limits If you change the measurement configuration alarms are turned off and the limit values are cleared Alarms are also turned off when you change the temperature probe type temperature units or disable the internal DMM e f you plan to use alarms on a channel which will also use scaling be sure to configure the scaling values first f you attempt to assign the alarm limits first the instrument will turn off alarms and clear the limit values when you enable scaling on that channel If you specify a custom measurement label with scaling it is automatically used when alarms are logged on that channel e f you remove a channel from the scan list by selecting CHANNEL OFF from the front panel or by redefining the scan list from the remote interface alarms are no longer evaluated on that channel during a scan but the limit values are not cleared If you decide to add that channel back to the scan list without changing the function the original limit values are restored and alarms are turned back on This makes it easy to temporarily remove a channel from the scan list without entering the alarm values again e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from th
332. n be letters numbers or an underscore _ You do not have to use all 12 characters but the first character must always be a letter 292 Chapter 5 Remote Interface Reference Calibration Commands CALibration SECure STATe OFF ON lt code gt CALibration SECure STATe Unsecure or secure the instrument for calibration The security code may contain up to 12 alphanumeric characters The STAT query reads the secured state of the instrument Returns 0 unsecured or 1 Secured CALibration STRing lt quoted_string gt Store a message in calibration memory in the mainframe Storing a calibration message will overwrite any message previously stored in memory The following statement shows how to store a message in calibration memory CAL STRING CAL 06 01 98 e The calibration message may contain up to 40 characters From the front panel you can view 13 characters of the message at a time e You can record a calibration message only from the remote interface and only when the instrument is unsecured You can read the message from either the front panel or over the remote interface You can read the calibration message whether the instrument is secured or unsecured e The calibration message is stored in non volatile memory in the mainframe and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command CALibration STR
333. n board SMB connectors or to the SMB to BNC cables provided with the module 1 12 XY 99 L Bank Switch o Comi A 7 13 A 14 21 oO 22 lt 98 alt Bank Switch o Com2 A y 23 om 24 NOTES e The HP 34905A is used for 509 applications The HP 34906A is used for 759 applications e You can close only one channel per bank at a time on these modules closing one channel in a bank will open the previously closed channel One channel in each bank is always connected to COM e This module responds only to the CLOSE command OPEN does not apply To OPEN a channel send the CLOSE command to another channel in the same bank 172 Chapter 4 Features and Functions HP 34905A 6A Dual 4 Channel RF Multiplexers h fa ae a oO WIRING LOG Slot Number 100 0200 300 EH Ch Name Comments ZD E 11 12 13 14 COM1 21 22 23 24 COM2 Refer to the diagrams on page 20 to connect wiring to the module LZHJ ZZHJ Maximum Input Voltage 42 V Maximum Input Current 700 mA Maximum Switching Power 20 W A SMB to BNC Cable Ten cables are included with the module To order additional cables use the following cable kit part numbers 10 cables are included 34905 60001 502 cables 34906 60001 752 cables ZWO EZHI
334. name and phone number of the person to contact for a new calibration e You can record a calibration message only from the remote interface and only when the instrument is unsecured You can read the message from either the front panel or over the remote interface You can read the calibration message whether the instrument is secured or unsecured e The calibration message may contain up to 40 characters From the front panel you can view 13 characters of the message at a time Press L to scroll through the text of the message Press Db again to increase the scrolling speed e Storing a calibration message will overwrite any message previously stored in memory e The calibration message is stored in non volatile memory in the mainframe and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e Front Panel Operation Ce CAL MESSAGE Remote Interface Operation To store the calibration message send the following command CAL STRING CAL 06 01 98 158 Chapter 4 Features and Functions Calibration Overview Calibration Count You can query the instrument to determine how many calibrations have been performed Note that your instrument was calibrated before it left the factory When you receive your instrument be sure to read the count to determine its initial value The calibration count is stored in non volatile memo
335. nd Cable length is limited no additional hardware is to 45 ft 15 m command transfers to 60 ft 20 m required Drivers usually included in Only one instrument or Additional system flexibility Requires an expansion the operating system device can be connected multiple instruments can slot plug in card in PC per serial port be connected to the and associated drivers same HP IB port Cables readily available Cabling is susceptible to Direct Memory Transfers Requires special cable and inexpensive noise causing slow or are possible lost communications The HP 34970A is shipped with a serial cable Varying connector pinouts if internal DMM is ordered and styles Data transfers up to Data transfers up to 85 000 characters sec 750 000 characters sec You can overcome these cable length limitations using special communications hardware For example you can use the HP E2050A LAN to HP IB Gateway interface or a serial modem 51 Chapter 3 System Overview Data Acquisition System Overview Measurement Software A variety of software is available to configure your data acquisition hardware and manipulate and display your measurement data Data Logging and Monitoring HP BenchLink Data Logger is a Windows based application designed to make it easy to use the HP 34970A with your PC for gathering and analyzing measurements The software is included with the HP 34970A when you order the internal DMM Use thi
336. nd reset the count to 0 after it is read select the RRESet parameter this means read and reset CONFigure TOTalize READ RRESet lt scan_list gt Configure the instrument to read the specified totalizer channels on the multifunction module but do not initiate the scan Note that this command also redefines the scan list The totalizer channel is numbered s03 wheres represents the slot number To read the totalizer during the scan without resetting the count select the READ parameter To read the totalizer during the scan and reset the count to 0 after it is read select the RRESet parameter this means read and reset SENSe TOTalize TYPE READ RRESet lt ch_list gt TOTalize TYPE lt ch_list gt Disable default or enable an automatic reset of the count when the specified totalizer channels are scanned To read the count without resetting the value select the READ parameter To read the totalize and reset the count to O after it is read select the RRESet parameter this means read and reset The totalizer channel is numbered s03 where s represents the slot number The TYPE query returns the reset configuration currently selected Returns READ or RRES 256 Chapter 5 Remote Interface Reference Totalizer Commands SENSe TOTalize SLOPe NEGative POSitive lt ch_list gt TOTalize SLOPe lt ch_list gt
337. nels Each channel must be a multiplexer channel that have been configured to be part of the scan list The minimum maximum average count and peak to peak value are cleared The values for all scanned channels are also cleared at the start of a new scan DATA LAST lt num_rdgs gt lt channel gt Query the last reading taken on the specified channel one channel only during the scan Use the optional num_rdgs parameter to specify the number of readings that you want to retrieve for the specified channel oldest data first If you do not specify a value for num_rdgs only the most recent reading on the specified channel is returned If you specify more readings than are currently stored in memory an error is generated 234 Chapter 5 Remote Interface Reference Scanning Overview Scan Memory Commands You can store up to 50 000 readings in non volatile memory during a scan Readings are stored only during a scan and all readings are automatically time stamped If memory overflows the MEM annundator will turn on a status register bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved You can read the contents of memory at any time even during a scan Reading memory is not cleared when you read it Each reading is stored with measurement units time stamp channel number and alarm status information You can specify which information you want returned wit
338. new scan is started when the CALC AVER CLEAR command described on the next page is executed after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command CALCulate AVERage MINimum lt ch_list gt Read the minimum value found on each of the specified channels during the scan Each channel must be a multiplexer channel that has been configured to be part of the scan list If no data is available for the specified channels 0 is returned Returns a number in the form 2 61920000E 01 CALCulate AVERage MINimum TIME lt ch_list gt Read the time the minimum reading was taken on the specified channel during the scan in full time and date format This command is not affected by the FORMat READ TIME TYPE command Returns the time in the form 1997 06 02 18 30 00 000 J une 1 1997 at 6 30 PM CALCulate AVERage MAXimum lt ch_list gt Read the maximum value found on each of the specified channels during the scan Each channel must be a multiplexer channel that has been configured to be part of the scan list If no data is available for the specified channels 0 is returned Returns a number in the form 2 61920000E 01 CALCulate AVERage MAXimum TIME lt ch_list gt Read the time the minimum reading was taken on the specified channel during the scan in full time and date format The command is not affect
339. ng instrument states reading errors running a self test displaying messages on the front panel setting the system clock disabling the internal DMM reading the firmware revisions and reading the relay cycle count State Storage The instrument has six storage locations in non volatile memory to store instrument states The locations are numbered 0 through 5 The instrument uses location 0 to automatically hold the state of the instrument at power down You can also assign a name to each of the locations 1 through 5 for use from the front panel e You can store the instrument state in any of the six locations However you can only recall a state from a location that contains a previously stored state You can use location 0 to store a sixth instrument state However keep in mind that location 0 is automatically overwritten when power is cycled e Theinstrument stores the state of all modules including all channel configurations scanning setups alarm values and scaling values e When shipped from the factory storage locations 1 through 5 are empty location 0 has the power on state e When shipped from the factory the instrument is configured to automatically recall the power down state state O when power is restored You can change the factory configuration such that a Factory Reset RST command is issued when power is restored e Before recalling a stored state the instrument
340. nnels When you specify a range of channels the range may contain invalid channels they are ignored but the first and last channel in the range must be valid The scan list now contains channels 5 through 10 slot 100 and channel 15 slot 200 ROUT SCAN 105 110 215 181 Chapter 5 Remote Interface Reference SCPI Command Summary Rules for Using scan_list and ch_list Parameters Before you can initiate a scan you must set up a scan list to include all desired multiplexer or digital channels Channels which are not in the list are skipped during the scan The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300 e Commands which accept a scan_list parameter will reprogram the scan list each time you send the command to the instrument The scan_list parameter is never an optional parameter e Commands which accept an optional ch_list parameter do not reprogram the scan list when you send the command to the instrument If you omit the ch_list parameter the command will be applied to the channels in the active scan list e f a command specifies an illegal operation on a given channel the instrument will generate an error for each channel which is illegal and the command will not be performed on any of the channels For example the following command will generate an error on channel 121 on the HP 34901A module since this channel is for current measurements only CONFigure VOLTa
341. nnunciator 4 offset B Mx B scaling 39 119 offset compensation 115 371 offset voltages 105 On Standby switch 17 ONCE annunciator 4 Open key 26 OPEN T C message 107 221 operating system requirements 412 Option 001 internal DMM See Option 001 Installation Note output format alarm queue data 127 output lines alarms 124 128 OUTP ALARm CLEar command 252 OUTP ALARm CLEar ALL command 252 OUTP ALARm MODE command 252 OUTP ALARm SLOPe command 252 P parameter types SCPI 300 parity RS 232 factory setting 152 selecting 47 152 pasting channel configuration 25 period measurements connections 21 sources of error 377 PLC 103 344 405 command syntax 218 vs channel delays 89 plug in module description HP 34901A 164 HP 34902A 166 HP 34903A 168 HP 34904A 170 HP 34905A 172 HP 34906A 172 HP 34907A 174 HP 34908A 176 plug in module information connecting wiring 20 default settings 162 dimensions 413 firmware revision 146 installing in mainframe 20 reading relay count 147 strain relief 20 specifications 409 poisson strain 373 polarity alarm output lines 129 ports serial COM 273 power consumption 408 power cord 17 power failure during scan 77 power line cycles 103 344 Power Standby switch 17 power down recall 48 77 140 power line fuse location 5 28 part number 27 replacing 28 factory setting 27 power line voltage factory setting 27
342. nstrument to determine the present SCPI version Returns a string in the form YYYY V where YYYY represents the year of the version and V represents a version number for that year e g 1994 0 TST Perform a complete self test of the instrument Returns O if the self test is successful or 1 if the test fails WAI Wait until the completion of the current scan to process any further commands To abort the scan send a Device Clear command Note that this command will wait until the entire scan is complete may hang indefinitely if a continuous scan is in progress OPC Set the Operation Complete bit bit 0 in the Standard Event register at the completion of the current scan Note that this command will wait until the entire scan is complete may hang indefinitely if a continuous scan is in progress 295 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language An Introduction to the SCPI Language SCPI Standard Commands for Programmable Instruments is an ASCI I based instrument command language designed for test and measurement instruments Refer to Simplified Programming Overview starting on page 201 for an introduction to the basic techniques used to program the instrument over the remote interface SCPI commands are based on a hierarchical structure also known as a tree system In this system associated commands are grouped together under a comm
343. nt to 1 sweep e Fromthe front panel a Factory Reset Sto Rci menu sets the scan interval to 10 seconds and the scan count to continuous From the remote interface a Factory Reset RST command sets the scan interval to immediate 0 seconds and the scan count to 1 sweep e Front Panel Operation To select interval scanning and set a scan interval time hour minutes seconds choose the following item Interval INTERVAL SCAN Toinitiate the scan and store all readings in memory press the SCAN annunciator will turn on Between scan sweeps the count down time is shown on the front panel 00 04 TO SCAN Note Tostop ascan press and hold e Remote Interface Operation The following program segment configures the instrument for an interval scan TRIG SOURCE TIMER Select the interval timer configuration RIG TIMER 5 Set the scan interval to 5 seconds TRIG COUNT 2 Sweep the scan list 2 times INIT Initiate the scan Note Tostop a scan send the ABORt command 81 Chapter 4 Features and Functions Scanning Scan Once n this configuration the instrument waits for either a front panel key press or a remote interface command before sweeping through the scan list e All readings from the scan are stored in non volatile memory Readings accumulate in memory until the scan is terminated until the scan count is reached or until you abort the scan e You can specify a scan count which sets the n
344. nterface Reference The MEASure and CONFigure Commands CONFigure Command Syntax CONFigure TEMPerature TCouple B E J K N R S T DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for thermocouple measurements but do not initiate the scan Note that this command also redefines the scan list The default DEF transducer type is a J Type thermocouple CONFigure TEMPerature RTD FRTD 85 91 DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for 2 wire or 4 wire RTD measurements but do not initiate the scan Use 85 to specify 0 00385 or 91 to spedfy 0 00391 Note that this command also redefines the scan list The default DEF type is 85 a 0 00385 For 4 wire RTD measurements FRTD the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections F or example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Specify the paired channel in the lower bank source as the scan_list channel CONFigure TEMPerature THERmistor 2252 5000 10000 DEF 1 lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for thermistor measurements but do not initiate the scan Note that this command also redefines the
345. nternal systems Each plug in module also has its own on board microprocessor You can query the instrument and each module to determine which revision of firmware is installed for each microprocessor The instrument returns three revision numbers The first number is the firmware revision number for the measurement processor the second is the input output processor and the third is the front panel display processor F or each plug in module the instrument returns one revision number for the on board processor Front Panel Operation REV X X Y Y 2Z 2 Turn the knob to read the firmware revision number for the module installed in each of the three slots If a slot does not contain a module EMPTY SLOT is displayed Remote Interface Operation Use the following command to read the system firmware revision numbers be sure to dimension a string variable with at least 40 characters IDN The above command returns a string in the form HEWLETT PACKARD 34970A 0 X X Y Y Z Z Use the following command to read the firmware revision number of the module in the specified slot be sure to dimension a string variable with at least 30 characters SYSTem CTYPe 100 2001300 This command returns a string in the form HEWLETT PACKARD 34901A 0 X X 146 Chapter 4 Features and Functions System Related Operations Relay Cycle Count The instrument has a Relay Maintenance System to help you predict relay end of life The instrument coun
346. o generated if you change the function on the reference channel after selecting the external reference for a thermocouple channel If you select a fixed reference temperature specify a value between 20 C and 80 C always specify the temperature in C regardless of the temperature units currently selected The accuracy of the measurement is highly dependent upon the thermocouple connections and the type of reference junction used Use a fixed temperature reference for the highest accuracy measurements The internal isothermal block reference provides the lowest accuracy measurements F or more information on reference junction temperature measurements and associated errors see the discussion starting on page 352 The thermocouple check feature allows you to verify that your thermocouples are properly connected to the screw terminals for measurements If you enable this feature the instrument measures the channel resistance after each thermocouple measurement to ensure a proper connection If an open connection is detected greater than 5 kQ on the 10 kQ range the instrument reports an overload condition for that channel or displays oP EN T cC on the front panel 107 Chapter 4 Features and Functions Temperature Measurement Configuration e Front Panel Operation To select the thermocouple function on the active channel choose the following items TEMPERATURE THERMOCOUPLE To se
347. o the G terminal 2 IN enables counting and a low signal disables TOT gt Channel 03 counting A TTL low signal applied to the G Gale terminal enables counting and a high signal Analog Output DAC Thetwo analog outputs are capable of outputting calibrated voltages between 12 volts with 16 bits of resolution Each DAC channel is capable of 10 mA maximum current You must limit the DAC 2 Channel 05 DAC output current to 40 mA total for all three slots Six DAC channels DAC 1 2 Channel 04 174 Chapter 4 Features and Functions HP 34907A Multifunction Module 5 _ 2 WIRING LOG Slot Number 1100 0200 300 cI Comments ZD _ Threshold Jumper AC TTL i 03 Totalizer Input Input Gate Gate 8 8 S in 5 NS so Song ms Fo Er EHI Output GND x Output GND Threshold Jumper Position O TTL O AC EYG g ZHI Z LYOd Refer to the diagrams on page 20 to connect wiring to the module ozn DODOODOAODOOOIOCOOOODODDODD lobogo ie Digital Input Output RO AWG Typical Eon ozo oz Vin L lt 0 8V TTL S Jog Vin H gt 2 0V TTL Simm a 32 Vout L lt 0 8V lout 400 mA e ay S
348. olute time time of day with date or relative time time since start of scan The default is relative time This command operates in conjunction with the FORMat READing TIME command they are not mutually exclusive The TYPE query returns ABS or REL Note The absolute format is considerably slower than the relative format 264 Chapter 5 Remote Interface Reference System Related Commands IDN Read the instrument s identification string The instrument returns three numbers for the system firmware The first number is the firmware revision number for the measurement processor the second is for the input output processor and the third is for the front panel processor An example string is shown below HEWLETT PACKARD 34970A X X X X X X X Be sure to dimension a string variable with at least 40 characters SYSTem CTYPe 100 200 300 Read the identity of the module in the specified slot For example the HP 34903A 20 Channel Actuator returns HEWLETT PACKARD 34903A 0 1 0 The last number 1 0 in this example is the firmware revision number for the module DIAGnostic POKE SLOT DATA 100 200 300 lt quoted_string gt PEEK SLOT DATA 100 200 300 Add a custom label to the module in the specified slot You can specify a custom label with up to 10 characters any additional characters are truncated no error is generated One possible use for this command is to allow you to differentiate
349. on System Overview You can use the HP 34970A as a stand alone instrument but there are many applications where you will want to take advantage of the built in PC connectivity features A typical data acquisition system is shown below Transducers Plug in System Sensors Interface Cable HP 34970A Modules Cabling and Events 50 Chapter 3 System Overview Data Acquisition System Overview The system configuration shown on the previous page offers the following advantages e You can use the HP 34970A to perform data storage data reduction mathematical calculations and conversion to engineering units You can use the PC to provide easy configuration and data presentation e You can remove the analog signals and measurement sensors from the noisy PC environment and electrically isolate them from both the PC and earth ground e You can use a single PC to monitor multiple instruments and measurement points while performing other PC based tasks The Computer and Interface Cable Since computers and operating systems are the subject of many books and periodicals they are not discussed in this chapter In addition to the computer and operating system you will need a serial port RS 232 or HP IB port IEEE 488 and an interface cable Serial RS 232 HP IB IEEE 488 Advantages Disadvantages Advantages Disadvantages Often built into the computer Cable length is limited Speed faster data a
350. on node or root thus forming subsystems A portion of the SENSE subsystem is shown below to illustrate the tree system SENSe VOLTage DC RANGe lt range gt MINimum MAXimum lt ch_list gt VOLTage DC RANGe lt ch_list gt MINimum MAXimum FREQuency VOLTage RANGe lt range gt MINimum MAXimum lt ch_list gt FREQuency VOLTage RANGe lt ch_list gt MINimum MAXimum RESistance OCOMpensated OFF ON lt ch_list gt RESistance OCOMpensated lt ch_list gt TEMPerature RJUNction lt ch_list gt SENSe is the root keyword of the command VOLTage and FREQuency are second level keywords and Dc and voLTage are third level keywords A colon separates a command keyword from a lower level keyword 296 Chapter 5 Remote Interface Reference An Introduction to the SCPI Language Command Format Used in This Manual The format used to show commands in this manual is shown below VOLTage DC RANGe lt range gt MINimum MAXimum lt ch_list gt The command syntax shows most commands and some parameters as a mixture of upper and lower case letters The upper case letters indicate the abbreviated spelling for the command For shorter program lines send the abbreviated form For better program readability send the long form For example in the above syntax statement VOLT and VOLTAGE are both acceptable forms You can us
351. operations if that port is already configured to be part of the scan list digital input You must specify a decimal value binary data is not accepted If you are going to write to both ports simultaneously WORD you must send the command to port 01 The digital output channels are numbered s01 lower byte and s02 upper byte where s represents the slot number The BYTE or WORD query returns the last byte or word sent to the specified digital output channel Returns a number in the form 255 SOURce DIGital STATe lt ch_list gt Read the last byte or word sent the specified digital output channels The digital output channels are numbered s01 lower byte and s02 upper byte where s represents the slot number This command returns 0 if the channel is an input port or 1 if the channel is an output port DAC Output Commands SOURce VOLTage lt voltage gt lt ch_list gt VOLTage lt ch_list gt Set the output voltage level on the specified DAC channel You can set the output voltage to any value between 12 Vdc and 12 Vdc in 1 mV steps Each DAC channel is capable of 10 mA maximum output current The DAC channels are numbered s04 and s05 wheres represents the slot number The voLT query returns the output voltage level on the specified DAC channel Returns a number in the form 8 00000000E 00 258 Chapter 5 Remote Interface Referen
352. or falling edge of the input signal e The maximum count is 67 108 863 276_ 1 The count rolls over to 0 after reaching the maximum allowed value e You can configure the totalizer to read without affecting the count or reset the count to zero without losing any counts 66 Chapter 3 System Overview Control Output Control Output In addition to signal routing and measurement you can also use the HP 34970A to provide simple control outputs For example you can control external high power relays using the actuator module or a digital output channel The Multifunction Module The multifunction module HP 34907A adds two additional control output capabilities to the system digital output and voltage DAC output The multifunction module also contains digital input and event totalizer capabilities which are described in more detail on pages 65 and 66 Digital Output The multifunction module has two non isolated 8 bit input output ports which you can use to output digital patterns Each port has a separate channel number on the module and contains 8 bits You can combine the two ports to output a 16 bit word 2 Bito 2 8 A L Port 1 LSB QD Channel 01 Digital 2 Bit7 Output 2 Bito 8 2 Port 2 MSB 2 Channel 02 2 2 Bit7 67 Chapter 3 System Overview Control Output Voltage DAC Output The multifunction module has two analog outputs capable of outputting calibrated voltag
353. or fast filter based on the input frequency that you specify for the selected channels Applies to ac voltage and ac current measurements only Input Frequency Default Settling Delay Minimum Settling Delay 3 Hz to 300 kHz Slow 7 seconds reading 1 5 seconds 20 Hz to 300 kHz Medium 1 second reading 0 2 seconds 200 Hz to 300 kHz Fast 0 12 seconds reading 0 02 seconds e Theinstrument selects the medium filter 20 Hz when the function is changed or after a Factory Reset RST command An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not change the setting e Front Panel Operation First select the ac voltage or ac current function on the active channel Then go to the Advanced menu and select the slow filter 3 Hz medium filter 20 Hz or fast filter 200 Hz for the active channel The default is the medium filter LF 3 HZ SLOW e Remote Interface Operation Specify the lowest frequency expected in the input signal on the specified channels The instrument selects the appropriate filter based on the frequency you specify see table above The MEASure and CONFigure commands automatically select the 20 Hz medium filter SENS VOLT AC BAND 3 203 Select the slow filter 3 Hz 114 Chapter 4 Features and Functions Resistance Measurement Configuration Resistance Measurement Configuration To connect resistances to the module s screw t
354. ou can use for outputting digital patterns 1 Select the Digital Output port Select the slot containing the multifunction module and continue turning the knob until DIN is displayed channel 01 or 02 2 Enter the bit pattern editor Notice that the port is now converted to an output port DOUT Cegceegeage Gaus Binary Display Shown Bit 7 Bit 0 3 Edit the bit pattern Use the knob and CJ or gt keys to edit the individual bit values You can specify whether you want to use binary or decimal format Once you have selected the number base it is used for all input or output operations on the same port To change the number base 24d DOUT Decimal Display Shown 4 Output the bit pattern to the specified port The specified bit pattern is latched on the specified port To cancel an output operation in progress wait for the display to time out 43 _ Chapter 2 Front Panel Overview To Read the Totalizer Count To Read the Totalizer Count The multifunction module HP 34907A has a 26 bit totalizer which can count pulses at a 100 kHz rate You can manually read the totalizer count or you can configure a scan to read the count Select the totalizer channel Select the slot containing the multifunction module and continue turning the knob until TOTALIZE is displayed channel 03 Configure the totalize mode The internal count starts as soon as you turn on the instrument You can configure the totalize
355. out 118 SMB cable kits 173 430 Index snubber circuitry 385 software BenchLink Data Logger creating floppy disks 19 installation 18 19 on line help 19 overview 6 system requirements 412 source connections 380 source connections RTD 110 SOUR DIG DATA BYTE command 258 SOUR DIG DATA WORD command 258 SOUR DIG STATe command 258 SOUR VOLTage command 258 SCPI language short form 297 SPDT Form C switching 59 384 specifications 203 220 ac accuracy 406 BenchLink Data Logger 412 dc accuracy 404 plug in modules 409 speed scanning 405 407 standard event register bit definitions 282 clearing bits 283 standard operation register bit definitions 285 clearing bits 285 Standby Power switch 17 state storage definition 48 front panel operation 141 naming states 48 140 power down recall 140 remote operation 141 statistics while scanning 75 status byte bit definitions 277 clearing bits 277 status register alarm register 284 condition register 275 enable register 275 example program 330 event register 275 questionable data register 280 register diagram 276 standard event register 282 standard operation register 285 status byte 277 STATus ALARm COND command 289 STATus ALARm ENABle command 289 STATus ALARm EVENt command 289 STATus OPER COND command 290 STATus OPER ENABle command 290 STATus OPER EVENt command 290 STATus PRESet
356. owing items and then set the desired bit pattern Set each bit to 0 1 or X don t care You can either specify that an alarm will occur when certain bits change or when a specific 8 bit pattern is read NOT PATTERN PATTERN MATCH gaxioni BIN Bit 7 Bit 0 To configure an alarm on a totalizer channel select a high limit and then set the desired count for the selected alarm m HI ALARM ONLY 130 Chapter 4 Features and Functions Alarm Limits e Remote Interface Operation Digital Input Channel To assign the alarm number to report any alarm conditions on the specified digital input channels use the following command OUTPut ALARm 1 2 3 4 SOURce lt ch_list gt To configure alarms on the specified digital input channel use the following commands also see the example on the following page CALCulate COMPare TYPE EQUal NEQual lt ch_list gt COMPare DATA lt data gt lt ch_list gt COMPare MASK lt mask gt lt ch_list gt Select EQUal1 to generate an alarm when the data read from the port is equal to CALC COMP DATA after being masked by CALC COMP MASK Select NEQual not equal to generate an alarm when the data read from the port is not equal to CALC COMP DATA after being masked by CALC COMP MASK Use CALC COMP MASK to designate the don t care bits Bits that you set to 0 in the mask are ignor
357. pecified channels use the following commands CALC LIMIT UPPER 5 25 103 212 CALC LIMIT LOWER 0 025 103 212 To enable the upper and lower alarm limits on the specified channels use the following commands CALC LIMIT UPPER STATE ON 103 212 CALC LIMIT LOWER STATE ON 103 212 125 Chapter 4 Features and Functions Alarm Limits Viewing Stored Alarm Data If an alarm occurs on a channel as it is being scanned then that channel s alarm status is stored in reading memory as the readings are taken As alarm events are generated they are also logged in an alarm queue which is separate from reading memory This is the only place where non scanned alarms get logged alarms during a monitor alarms generated by the multifunction module etc e You can store up to 50 000 readings in memory during a scan You can read the contents of reading memory at any time even during a scan Reading memory is not cleared when you read it e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan Therefore the contents of memory are always from the most recent scan e Upto 20 alarms can be logged in the alarm queue If more than 20 alarms are generated they will be lost only the first 20 alarms are saved e The alarm queue is cleared by the cLs clear status command when power is cycled and
358. per channel basis e From the remote interface the time stamp information is returned either in absolute time time of day with date or relative time time since start of scan Use the FoRMat READ TIME TYPE command to select absolute or relative time From the front panel the time stamp is always returned in absolute time e The MEASure and CONFigure commands automatically turn off the units time channel and alarm information e A Factory Reset RST command turns off the units time channel and alarm information e Remote Interface Operation The following commands select the format of readings returned from a scan FORMat READing ALARm ON FORMat READing CHANnel ON FORMat READing TIME ON FORMat READing TIME TYPE ABSolute RELative FORMat READing UNIT ON The following is an example of a reading stored in memory with all fields enabled relative time is shown 2 61950000E 01 Cj 00000000 017 4 101 2 1 Reading with Units 26 195 C 3 Channel Number 2 Time Since Start of Scan 17 ms 4 Alarm Limit Threshold Crossed 0 No Alarm 1 LO 2 HI 87 Chapter 4 Features and Functions Scanning Channel Delay You can control the pace of a scan sweep by inserting a delay between multiplexer channels in the scan list useful for high impedance or high capacitance circuits The delay is inserted between the relay closure and the actual mea
359. pose of grounding is to avoid ground loops and minimize noise Most systems should have at least three separate ground returns 1 One ground for signals You may also want to provide separate signal grounds between high level signals low level signals and digital signals 2 A second ground is used for noisy hardware such as relays motors and high power equipment 3 A third ground is used for chassis racks and cabinets The ac power ground should generally be connected to this third ground In general for frequencies below 1 MHz or for low level signals use single point grounding see below Parallel grounding is superior but is also more expensive and more difficult to wire If single point grounding is adequate the most critical points those with the lowest levels and or the most precise measurement requirements should be positioned near the primary ground point For frequencies above 10 MHz use the separate grounding system For signals between 1 MHz and 10 MHz you can use a single point system if the longest ground return path is kept to less than 1 20 of a wavelength In all cases return path resistance and inductance should be minimized Circuit A Circuit B Circuit C Circuit A Circuit B Circuit C V Single Point Ground Circuit A Circuit B Circuit C V Parallel Grounds Separate Grounds 337 LO HI Chapter 8 Tutorial System Cabling and Conn
360. practice or condition that could possibly cause damage to equipment or permanent loss of data Earth ground symbol yr Chassis ground symbol Warning Only qualified service trained personnel who are aware of the hazards involved should remove the cover from the instrument or connect external wiring to a plug in module Warning For continued protection against fire replace the line fuse only with a fuse of the specified type and rating Printed October 1997 Edition 2 Printed in U S A
361. press again When you return to the menu you will see new choices CAL SECURED and UNSECURE CAL e Remote Interface Operation To secure the instrument send the following command with the desired security code CAL SECURE STATE ON HP034970 To Change the Security Code To change the security code you must first unsecure the instrument and then enter a new code Make sure you have read the security code rules described on page 155 before attempting to change the security code e Front Panel Operation To change the security code first make sure that the instrument is unsecured Go to the SECURE CAL entry enter the new security code and press the instrument is now secured with the new code Changing the code from the front pane also changes the code as seen from the remote interface e Remote Interface Operation To change the security code first unsecure the instrument using the old security code Then enter the new code as shown below CAL SECURE STATE OFF HP034970 Unsecure with old code CAL SECURE CODE 2Z2Z007943 Enter new code 157 Chapter 4 Features and Functions Calibration Overview Calibration Message The instrument allows you to store one message in calibration memory in the mainframe For example you can store such information as the date when the last calibration was performed the date when the next calibration is due the instrument s serial number or even the
362. put terminals are both driven by an earth referenced signal Vp then a current will flow through Rg and create a voltage drop Vz as shown below Any resulting voltage V1 will appear as an input to the internal DMM As the value of Rg approaches zero so does the error Additionally if V is at the power line frequency 50 Hz or 60 Hz the noise can be greatly reduced by setting the internal DMM s integration time to 1 PLC or greater see page 103 for a discussion of integration time l l 1 HI athe 1 Viest DMM Rs gt LO O VL i Sey E 250pF 7 T DRR Vi gt 10 GQ l eG 1 Where Vf Common mode float voltage Rg LO lead resistance Rj Isolation resistance Ci Isolation capacitance Zi Parallel impedance of Ri Ci Vi x Rg Error VL Ag Z 355 Chapter 8 Tutorial Measurement Fundamentals Noise Caused by Injected Current Residual capacitances in the instrument s power transformer cause small currents to flow from the LO terminal of the internal DMM to earth ground The frequency of the injected current is the power line frequency or possibly harmonics of the power line frequency The injected current is dependent upon the power line configuration and frequency A simplified circuit is shown below LO O 4 Injected Current V_ 80 60 Hz ac line leakage current S77 With Connection A see below the injecte
363. r Card Reset SYSTem CPON command does not change the resolution setting e Front Panel Operation First select the measurement function on the active channel You are automatically guided to the next level of the menu where you can select the number of digits The default is 5 digits 6 1 2 DIGITS For temperature measurements go to the menu and select the number of digits displayed past the decimal point on the selected channel DISPLAY 1 C 101 Chapter 4 Features and Functions General Measurement Configuration e Remote Interface Operation Specify the resolution in the same units as the measurement function not in number of digits F or example if the function is dc volts specify the resolution in volts For frequency specify the resolution in hertz You can select the resolution using parameters in the MEASure and CONF igure commands F or example the following statement selects the 10 Vdc range with 444 digits of resolution on channel 301 CONF VOLT DC 10 0 001 301 The following statement selects the 1 A range with 6 digits of resolution on channel 221 MEAS CURR AC 1 1E 6 221 You can also select the resolution using the SENSe commands For example the following statement specifies a 4 wire ohms measurement with 100Q of resolution on channel 103 SENS FRES RES 100 103 102 Chapter 4 Features and Functions General Measurement Configuration Custom A
364. r for incidental or consequential damages in connection with the fur nishing performance or use of this material No part of this document may be photocopied reproduced or translated to another language without the prior written consent of HP Restricted Rights The Software and Docu mentation have been developed entirely at private expense They are delivered and licensed as commercial computer software as defined in DFARS 252 227 7013 Oct 1988 DFARS 252 211 7015 May 1991 or DFARS 252 227 7014 Jun 1995 as a commercial item as defined in FAR 2 101 a or as restricted computer software as defined in FAR 52 227 19 Jun 1987 or any equivalent agency regulation or contract clause whichever is appli cable You have only those rights provided for such Software and Documenta tion by the applicable FAR or DFARS clause or the HP standard software agreement for the product involved Trademark Information Windows Windows 95 and Windows NT are registered trademarks of Microsoft Corp Safety Do not install substitute parts or perform any unauthorized modification to the product Return the product to an HP Sales and Service Office for service and repair to ensure that safety features are maintained Safety Symbols Warning Calls attention to a proce dure practice or condition that could possibly cause bodily injury or death Caution Calls attention to a proce dure
365. r resistance change per strain applied Strain gages are available in many patterns with various numbers and configurations of elements The most common element is the single gage form shown below Multi element strain gages also called rosettes are used to measure components of strain in different directions Two element 90 and three element 45 or 60 configurations are the most common HI Source HI Sense LO Sense LO Source Common Uses for Strain Gages Strain gages are used to sense many types of physical parameters Strain gages are primarily a force sensing device Force is measured indirectly by measuring the deformation of a test body to a known applied force thus producing a resistance change proportional to the applied force Many other physical quantities can be measured through force measurements Common applications of strain gages include weight pressure flow and level measurements 374 Chapter 8 Tutorial Measurement Fundamentals Making Strain Gage Measurements A Wheatstone bridge is commonly used to enable instruments with low sensitivity measuring capabilities to measure small resistance changes common in strain measurements Instruments with high resolution resistance measuring capabilities like the HP 34970A internal DMM can directly measure small resistance changes with high precision and linearity You should also use the 4 wire resistance method when measuring strain gages to eliminate system ca
366. r to reset the count to 0 after being read or it can count continuously and be manually reset READ RESET Read the count The count is read once each time you press the count does not update automatically on the display As configured in this example the count is automatically reset to 0 each time you read it 12345 TOT The count will be displayed until you press another key turn the knob or until the display times out To manually reset the totalizer count press 3 TOT READ choice Chapter 2 Front Panel Overview To Output a DC Voltage To Output a DC Voltage The multifunction module HP 34907A has two analog outputs capable of outputting calibrated voltages between 12 volts Select a DAC Output channel Select the slot containing the multifunction module and continue turning the knob until DAC is displayed channel 04 or 05 Enter the output voltage editor 400 000 V DAC Set the desired output voltage Use the knob and l or keys to edit the individual digits 405 250 V DAC Output the voltage from the selected DAC The output voltage will be displayed until you press another key or turn the knob To manually reset the output voltage to 0 volts press i 45 Sto Rel Interface Sto Rcl Interface Sto Rcl Interface Chapter 2 Front Panel Overview To Configure the Remote Interface To Configure the Remote Interface The instrument is shipped with both
367. rage locations I through 5 are empty location 0 has the power on state e You can use location 0 to store a sixth instrument state However keep in mind that location 0 is automatically overwritten when power is cycled e Before recalling a stored state the instrument verifies that the same module types are installed in each slot If a different module type is installed the instrument will perform the equivalent of a Card Reset SYSTem CPON command on that slot 261 Chapter 5 Remote Interface Reference State Storage Commands MEMory STATe NAME 1 2 3 4 5 lt name gt NAME 1 2 3 4 5 Assign a name to the specified storage location you cannot assign a name to location O You can name a location from the front panel or over the remote interface but you can only recall a named state from the front panel From the remote interface you can only recall a stored state using a number 0 through 5 The NAME query returns a quoted string containing the name currently assigned to the specified storage location If the specified location has no name assigned an empty string is returned e The name can contain up to 12 characters The first character must be a letter A Z but the remaining 11 characters can be letters numbers 0 9 or the underscore character _ Blank spaces are not allowed An error is generated if you specify a name with more than 12 characters An ex
368. ramming Overview 201 The MEASure and CONFigure Commands 207 Setting the Function Range and Resolution 214 Temperature Configuration Commands 219 Voltage Configuration Commands 223 Resistance Configuration Commands 224 Current Configuration Commands 224 Frequency Configuration Commands 225 Scanning Overview 226 Single Channel Monitoring Overview 237 Scanning With an External Instrument 239 Mx B Scaling Overview 244 Alarm System Overview 247 Digital Input Commands 255 Totalizer Commands 256 Digital Output Commands 258 DAC Output Commands 258 Switch Control Commands 259 State Storage Commands 261 System Related Commands 264 Interface Configuration Commands 269 RS 232 Interface Configuration 270 Modem Communications 274 The SCPI Status System 275 Status System Commands 286 Calibration Commands 292 Service Related Commands 294 An Introduction to the SCPI Language 296 Using Device Clear 302 Chapter 6 Error Messages Execution Errors 305 Instrument Errors 309 Self Test Errors 314 Calibration Errors 315 Plug In Module Errors 317 13 Q e gt r D amh N J c Q J c fe Contents Chapter 7 Application Programs Example Programs for Excel 7 0 321 Example Programs for C and C 328 Chapter 8 Tutorial System Cabling and Connections 335 Measurement Fundamentals 343 Low Level Signal Multiplexing 378 Actuators and General Purpose Switching 384 Matrix Switching 388 RF Sign
369. rations due to more stringent contact resistance requirements typically less than 0 2 The following table shows the time required to reach the specified number of switch operations for several switching speeds Continuous Switch Operations Switching Speed 400 000 1 000 000 10 000 000 1 Hour 12 Years 1 Minute 10 Weeks 2 Years 1 Second 1 Day 12 Days 4 Months 10 Second 3 Hours 1 Day 12 Days 399 Chapter 8 Tutorial Relay Life and Preventative Maintenance Relay Life As a relay is used the contacts begin to wear and the resistance of the closed contacts increases The initial contact resistance of a relay is typically 50 mQ plus lead resistance When the contact resistance exceeds 20 to 50 times its initial value the contact resistance becomes very erratic and the relay should probably be replaced For most applications a relay with contact resistance greater than 10 should be replaced The graph below shows the typical contact resistance characteristics of the relays used on the HP 34970A switching modules Typical Relay Lifetime g Full Load Typical Signals No Load S a7 6 12 S 6 02 O gt amp cc i ee 1k 10k 100k 1M 10M 100M Relay Operations Cycles Relay Load For most applications the load switched by the relay is the most important factor affecting relay life As shown in the graph below relay life is maximized by switching
370. re on the specified channels opens are reported as 9 90000000E 37 SENS TEMP TRAN TC CHECK ON 203 301 109 Chapter 4 Features and Functions Temperature Measurement Configuration RTD Measurements To connect an RTD to the module s screw terminals see page 21 The instrument supports RTDs with 0 00385 DIN IEC 751 or 0 00391 using ITS 90 software conversions The default is a 0 00385 The resistance of an RTD is nominal at 0 C and is referred to as Ro Theinstrument can measure RTDs with Ro values from 49a to 2 1 KQ The default is Ro 1009 PT 100 is a special label that is sometimes used to refer to an RTD with 0 00385 and Ro 1009 You can measure RTDs using a 2 wire or 4 wire measurement method The 4 wire method provides the most accurate way to measure small resistances Connection lead resistance is automatically removed using the 4 wire method For 4 wire RTD measurements the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections For example make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12 Front Panel Operation To select the 2 wire or 4 wire RTD function for the active channel choose the following items Measure TEMPERATURE RID RID 4W To select the nominal resistance Ro for
371. re unsecure the instrument for calibration View readings alarms and errors e View the last 100 scanned readings from memory last min max and average e View the first 20 alarms in the alarm queue reading and time alarm occurred e View up to 10 errors in the error queue e Read the number of cycles for the displayed relay relay maintenance feature Store and recall instrument states e Store up to five instrument states in non volatile memory e Assign a name to each storage location e Recall stored states power down state factory reset state or preset state Configure the remote interface e Select the HP IB address e Configure the RS 232 interface baud rate parity and flow control 36 Chapter 2 Front Panel Overview To Monitor a Single Channel To Monitor a Single Channel You can use the Monitor function to continuously take readings on a single channel even during a scan This feature is useful for troubleshooting your system before a test or for watching an important signal Select the channel to be monitored Only one channel can be monitored at a time but you can change the channel being monitored at any time by turning the knob Enable monitoring on the selected channel Any channel that can be read by the instrument can be monitored the MON annunciator turns on This includes any combination of temperature voltage resistance current frequency or period
372. rent topologies for various applications The following switching topologies are available e Multiplexer HP 34901A 34902A 34905A 34906A 34908A e Matrix HP 34904A e Form C Single Pole Double Throw HP 34903A The following sections describe each of these switching topologies 57 Chapter 3 System Overview Signal Routing and Switching Multiplexer Switching Multiplexers allow you to connect one of multiple channels to a common channel one at a time A simple 4 to 1 multiplexer is shown below When you combine a multiplexer with a measurement device like the internal DMM you create a scanner For more information on scanning see page 62 Channel 1 Common a Oo Channel 2 O lt Channel 3 O lt Channel 4 Multiplexers are available in several types e One Wire Single Ended Multiplexers for common LO measurements For more information see page 379 e Two Wire Multiplexers for floating measurements For more information see page 379 e Four Wire Multiplexers for resistance and RTD measurements For more information see page 380 e Very High Frequency VHF Multiplexers for switching frequencies up to 2 8 GHz For more information see page 390 58 Chapter 3 System Overview Signal Routing and Switching Matrix Switching A matrix switch connects multiple inputs to multiple outputs and therefore offers more switching flexibility than a multiplexer Use a matrix for switching low frequen
373. res and Functions Mx B Scaling e During a Monitor operation the gain and offset values are applied to all readings on the specified channel e You can specify a custom label with up to three characters You can use letters A Z numbers 0 9 an underscore _ or the character which displays a degree symbol on the front panel displayed as a blank space in an output string from the remote interface The first character must bea letter or the character the character is allowed only as the leftmost character in the label The remaining two characters can be letters numbers or an underscore Note If you set the measurement label to C F or K note that this has no effect on the temperature units set in the Measure menu e Although the instrument does not directly support strain gage measurements you can measure a strain gage using a 4 wire resistance measurement with scaling For more information refer to Strain Gage Measurements on page 373 Note HP BenchLink Data Logger software has built in strain gage measurement capability Use the following equations to calculate the gain and offset 1 1 GF x Ro er M Where GF is the gage factor and Ro is the unstrained gage resistance For example a 3502 strain gage with a gage factor of 2 would use the following gain and offset values M 0 001428571 B 0 5 be sure to use 614 digits of resolution for this measurement e The maximum ga
374. returned Read the response string errorStatus viRead vi ByVal readbuf 2048 actual replyString readbuf Strip out any nul s from the response string nulpos InStr replyString Chr 0 If nulpos Then replyString Left replyString nulpos 1 End If getScpi replyString End Function Continued on next page 323 Chapter 7 Application Programs Example Programs for Excel 7 0 Sub OpenPort Be sure that the HP IB address has been set in the VISAaddr variable before calling this routine Open the VISA session errorStatus viOpenDefaultRM videfaultRM Open communications to the instrument errorStatus viOpen videfaultRM GPIBO amp VISAaddr amp INSTR 0 2500 vi If an error occurs give a message If errorStatus lt VI_SUCCESS Then Range A2 Select Cells 1 1 Unable to Open Port End If End Sub Sub ClosePort errorStatus viClose vi Close the session errorStatus viClose videfaultRM End Sub OE Pre We We Pre OY OY We Pe OY OY We VY Oe OY OY ne ve ve Oye vy OY ve oe Oy OO neve ove Oven nee ne OY ony nove veto none toa na This subroutine is used to create delays The input is in seconds and fractional seconds are allowed Sub delay delay_time As Single Dim Finish As Single Finish Timer delay_time Do Loop Until Finish lt Timer End Sub 324 Chapter 7 Application Programs Example Programs for Excel 7 0
375. returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus QUEStionable ENABle lt enable_value gt STATus QUEStionable ENABle Enable bits in the enable register in this register group The selected bits are then reported to the Status Byte A cLs clear status will not clear the enable register but it does clear all bits in the event register A STATus PRESet Clears all bits in the enable register To enable bits in the enable register you must write a dedmal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The ENABle query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the STATus QUES ENABle command 287 Chapter 5 Remote Interface Reference Status System Commands Standard Event Register Commands See the table on page 282 for the register bit definitions ESR Query the event register in this register group This is a read only register Once a bit is set it remains set until cleared by a cLS clear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register ESE lt enable_value gt ESE Enable bits in the enable register in this register group The selected bits are then reported to the Status Byte A cLs clear status will not clear the enable register b
376. rface Reference Scanning With an External Instrument ROUTe CHANnel ADVance SOURce EXTernal BUS IMMediate CHANnel ADVance SOURce This command is valid only when the internal DMM is disabled or removed from the HP 34970A Select the source to provide the channel advance signal to the next channel in the scan list When the channel advance signal is received the instrument opens the currently selected channel and closes the next channel in the scan list The instrument will accept a software bus command an immediate continuous scan trigger an external TTL trigger pulse or an internally paced timer The default is E XTernal The SOUR query returns EXT BUS or IMM The channel advance signal is ignored unless you have initiated the scan INITiate command and have received a scan trigger TRIG SOUR command Although the ROUT CHAN ADV SOUR command shares some of the same signals as the TRIG SOUR command they cannot be set to the same source except IMMediate If you attempt to select the same source an error is generated and the TRIG SOUR is reset to IMMediate A channel advance signal is not required for digital input or totalizer channels included in the scan list Measurements on these channels are still performed by the HP 34970A and do not require synchronization with the external instrument 242 Chapter 5 Remote Interface Reference Scanning With an External Instrument RO
377. ritical to measurement success Some types of transducers such as thermocouples have very specific requirements for the type of cable that can be used to make connections Be sure to consider the usage environment when choosing wire gauge and insulation qualities Wire insulation typically consists of materials such as PVC or Teflon The table below lists several common cable types and describes their typical uses Note Wiring insulation and usage is described in more detail in System Cabling and Connections starting on page 335 Cable Type Common Uses Comments Thermocouple Extension Wire Thermocouple measurements Available in specific thermocouple types Also available in a shielded cable for added noise immunity Twisted Pair Shielded Twisted Pair Measurement inputs voltage outputs switching counting Most common cable for low frequency measurement inputs Twisted pair reduces common mode noise Shielded twisted pair provides additional noise immunity Shielded Coaxial Double Shielded Coaxial VHF signal switching Most common cable for high frequency signal routing Available in specific impedance values 50Q or 75Q Provides excellent noise immunity Double shielded cable improves isolation between channels Requires special connectors Flat Ribbon Twisted Pair Ribbon Digital Input Output Often used with mass termination connectors These cables provide litt
378. rnal DMM and the device under test are both referenced to a common earth ground a ground loop is formed As shown below any voltage difference between the two ground reference points V ground causes a current to flow through the LO measurement lead This causes an error voltage V1 which is added to the measured voltage RL HIO Viest DMM RL LOO Fu acs 250pF Ri gt 10 Ga Vground S liji s ee aa i M Where R Lead resistance Ri DMM isolation resistance Ci DMM isolation capacitance Vground Ground noise voltage V _ ground I Current flow caused by Vground RaZ a 1 Z Zci 5776 10 Ma at 50 or 60 Hz VL IxRL To minimize ground loop errors e If Veground is a dc voltage keep RL small compared to Ri e If Veground is an ac voltage keep RL small compared to Z and set the DMM s integration time to 1 PLC or greater see page 103 for a discussion of integration time 341 Chapter 8 Tutorial System Cabling and Connections Low Level AC Measurement Errors When measuring ac voltages less than 100 mV be aware that these measurements are especially susceptible to errors introduced by extraneous noise sources An exposed test lead will act as an antenna and the internal DMM will measure the signals received The entire measurement path including the power line act as a loop antenna Circulating currents in the loop will create error voltages a
379. rocedure 25 Chapter 1 Quick Start To Close a Channel To Close a Channel On the multiplexer and switch modules you can close and open individual relays on the module However note that if you have already configured any multiplexer channels for scanning you cannot independently close and open individual relays on that module i Select the channel Turn the knob until the desired channel is shown on the right side of front panel display For this example select channel 213 2 Close the selected channel 3 Open the selected channel Note will sequentially open all channels on the module in the selected slot The table below shows the low level control operations available for each of the plug in modules Plug In Module cose over reca Ce CD Ce 34901A 20 Channel Mux 34902A 16 Channel Mux 34908A 40 Channel Single Ended Mux e e 34903A 20 Channel Actuator e e 34904A 4x8 Matrix e 34905A Dual 4 Channel RF Mux 509 34906A Dual 4 Channel RF Mux 759 e 34907A Multifunction Module DIO e e e 34907A Multifunction Module Totalizer e 34907A Multifunction Module DAC e 1 Only one channel can be closed at a time on this module 2 Only one channel in each bank can be closed at a time on this module 26 i Chapter 1 Quick Start If the Instrument Does Not Turn On If the Instrument
380. ront panel only e Select one of the following 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud e The baud rate selection is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e Front Panel Operation 19200 BAUD Parity Selection RS 232 You can select the parity for RS 232 operation The instrument is configured for no parity with 8 data bits when shipped from the factory You can set the parity from the front panel only e Select one of the following None 8 data bits Even 7 data bits or Odd 7 data bits When you set the parity you are also indirectly setting the number of data bits e The parity selection is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e Front Panel Operation EVEN 7 BITS 152 Chapter 4 Features and Functions Remote Interface Configuration Flow Control Selection RS 232 Y ou can select one of several flow control methods to coordinate the transfer of data between the instrument and your computer or modem The method that you select will be determined by the flow method used by your computer or modem You can select the flow control method from the front panel only e Select one of the following
381. rrent measurements demands additional care The burden voltage loading varies with frequency and input inductance often causing unexpected behavior in the test circuit see the discussion on the following page 367 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in DC Current Measurements When you connect the internal DMM in series with a test circuit to measure current a measurement error is introduced The error is caused by the DMM s series burden voltage A voltage is developed across the wiring resistance and current shunt resistance of the internal DMM as shown below Rs re Vs Vs Source voltage Rg Source resistance Vp Burden voltage R Current shunt resistance 100 x Vp Error V S Sources of Error in AC Current Measurements Burden voltage errors which apply to de current also apply to ac current measurements However the burden voltage for ac current is larger due to the internal DMM s series inductance and the measurement connections The burden voltage increases as the input frequency increases Some circuits may oscillate when performing current measurements due to the internal DMM s series inductance and the measurement connections 368 Chapter 8 Tutorial Measurement Fundamentals Resistance Measurements An ohmmeter measures the dc resistance of a device or circuit connected to its input Resistance measurements are performed by supplying
382. ry in the mainframe and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SYSTem PRESet command The calibration count increments up to a maximum of 65 535 after which it rolls over to 0 Since the value increments by one for each calibration point a complete calibration may increase the value by many counts The calibration count is also incremented with calibrations of the DAC channels on the multifunction module Front Panel Operation CAL COUNT Remote Interface Operation CALibration COUNt 159 Chapter 4 Features and Functions Factory Reset State Factory Reset State The table below shows the state of the instrument after a FACTORY RESET from the Sto Rel menu or RST command from the remote interface Measurement Configuration Function Range Resolution Integration Time Input Resistance Channel Delay Totalizer Reset Mode Totalizer Edge Detect Scanning Operations Scan List Reading Memory Min Max and Average Scan Interval Source Scan Interval Scan Count Scan Reading Format Monitor in Progress Mx B Scaling Gain Factor M Scale Factor B Scale Label Alarm Limits Alarm Queue Alarm State HI and LO Alarm Limits Alarm Output Alarm Output Configuration Alarm Output State Alarm Output Slope Module Hardware HP 34901A 34902A 34908A HP 34903A 34904A HP 34905A 34906A HP 34907A System Relate
383. s byte register and clear SRQ Bit 6 64 indicates this SRQ is for our instrument bit 1 2 indicates an alarm and bit 5 32 indicates the standard event register so alarm 64 2 66 OPC 64 32 96 both 64 32 2 98 if statusByte 66 statusByte 98 srqFlag 1 Set flag to indicate this is an alarm viPrintf DataAcqu STATUS ALARM EVENT n Check and clear alarm viScanf DataAcqu s amp reply_string printf alarm event bit s n reply_string if statusByte 96 statusByte 98 srqFlag 1 Set flag to indicate end of operation viPrintf DataAcqu ESR n Check and clear ESR bit viScanf DataAcqu s amp reply_string printf Standard Event Register bit s n reply_string return VI_SUCCESS 331 Tutorial Tutorial This chapter describes methods that you can use to reduce errors that can affect your measurements You will also find information to help you better understand how the HP 34970A makes measurements and what you can do to get the best results This chapter is divided into the following sections e System Cabling and Connections starting on page 335 e Measurement Fundamentals starting on page 343 e Low Level Signal Multiplexing starting on page 378 e Actuators and General Purpose Switching starting on page 384 e Matrix Switching starting on page 388 e RF Signal Multiplexing starting on page 390 e Multifunction Modu
384. s not allowed for this command Check the list of parameters to verify that you have used a valid parameter type Example CALC SCALE STATE ON 306 168 178 211 213 214 221 222 223 224 Chapter 6 Error Messages Execution Errors Block data not allowed Data was sent to the instrument in SCPI definite length block format but this command does not accept this format Example SOUR DIG DATA 128 Expression data not allowed A channel list was received but is not allowed for this command Example SYST CTYPE 100 Trigger ignored More than one trigger was received while the instrument was scanning Triggers are occurring too frequently and you may need to slow them down Also make sure that you have selected the proper trigger source INIT ignored An INITiate command was received but could not be executed because a scan was already in progress Send an ABORt command or bus Device Clear to stop a scan in progress Trigger deadlock A trigger deadlock occurs when the trigger source is BUS and a READ command is received Settings conflict An invalid configuration was requested This error is most commonly generated when setting alarm limits Note that the lower limit must always be less than or equal to the upper limit even if you are using only one of the limits This error is also generated if you send the MEASure or CONFigure command with autorange enabl
385. s pins inside the connector shell and a female connector has holes inside the connector shell If you cannot find the correct cable for your configuration you may have to use a wiring adapter If you are using a DTE to DTE cable make sure the adapter is a straight through type Typical adapters include gender changers null modem adapters and DB 9 to DB 25 adapters 272 Chapter 5 Remote Interface Reference RS 232 Interface Configuration If your computer has a 9 pin serial port with a male connector use the cable included with the instrument if you ordered the internal DMM If you need an additional cable order the F1047 80002 cable which is part of the HP 34398A Cable Kit This cable has a 9 pin female connector on each end The cable pin diagram is shown below this is the pinout for the cable shipped with the HP 34970A For proper operation you must use an RS 232 cable with the same pinout as shown below DCD o RS 232 Cable N nstrument 2G RS 232 Troubleshooting Here are a few things to check if you are having problems communicating over the RS 232 interface If you need additional help refer to the documentation that came with your computer e Verify that the instrument and your computer are configured for the same baud rate parity and number of data bits Make sure that your computer is set up for 1 start bit and 1 stop bit these values are fixed on the instrument e Verify that you
386. s software to set up your test acquire and archive measurement data and perform real time display and analysis of your incoming measurements HP BenchLink Data Logger Automated Testing with Multiple Instruments e HP VEE e HP BASIC for Windows e National Instruments LabVIEW e Microsoft Visual Basic or Visual C 52 Chapter 3 System Overview Data Acquisition System Overview The HP 34970A Data Acquisition Switch Unit As shown below the logic circuitry for the HP 34970A is divided into two sections earth referenced and floating These two sections are isolated from each other in order to maintain measurement accuracy and repeatability for more information on ground loops see page 341 External Trigger a Optional Alarms Control em Floating Earth vam AF HP IB Referenced Pr Logic Sano Ut aha oe To Computer Digital Analog Bus RS 232 yp Bus gt 100 z AC Power Plug ug In 200 Slots a Optical Isolators 300 The earth referenced and floating circuitry communicate with each other via an optically isolated data link The earth referenced section communicates with the floating section to provide PC connectivity The instrument is shipped with both an HP IB IEEE 488 interface and an RS 232 interface Only one interface can be enab
387. s stored in reading memory only during a scan The STAT query returns the state of the comparison mode Returns O OFF or 1 ON 254 Chapter 5 Remote Interface Reference Digital Input Commands Digital Input Commands See also Digital Input Operations in chapter 4 starting on page 133 MEASure DIGital BYTE lt scan_list gt Configure the instrument to read the specified digital input channels on the multifunction module and immediately sweep through the scan list one time Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory The digital input channels are numbered s01 LSB and s02 MSB wheres represents the slot number Note that if you include both digital input channels in the scan list the instrument will read data from both ports simultaneously with the same time stamp This will allow you to externally combine the two 8 bit value into one 16 bit value CONFigure DIGital BYTE lt scan_list gt Configure the instrument to read the specified digital input channels on the multifunction module but do not initiate the scan Note that this command also redefines the scan list The digital input channels are numbered s01 LSB and s02 MSB where s is the slot number Note that if you include both digital input channels in the scan list the instrument wi
388. same code to unsecure it from the remote interface e Front Panel Operation UNSECURE CAL When you first enter the Utility menu the calibration entries toggle between CAL SECURED and UNSECURE CAL To unsecure the instrument select UNSECURE CAL and press After entering the correct security code press again When you return to the menu you will see new choices CAL UNSECURED and SECURE CAL Note f you enter the wrong secure code NO MATCH is displayed and a new choice EXIT is shown e Remote Interface Operation To unsecure the instrument send the following command with the correct security code CAL SECURE STATE OFF HP034970 156 Chapter 4 Features and Functions Calibration Overview To Secure Against Calibration You can secure the instrument either from the front panel or over the remote interface The instrument is secured when shipped from the factory and the security code is set to HP034970 e Once you enter a security code that code must be used for both front panel and remote operation For example if you secure the instrument from the front panel you must use that same code to unsecure it from the remote interface e Front Panel Operation vw SECURE CAL When you enter the Utility menu the calibration entries toggle between CAL UNSECURED and SECURE CAL To secure the instrument select SECURE CAL and press After entering the desired security code
389. sed as a programmable voltage source for analog input to other devices Output Voltage 16 Bit P g Digital Data DAC gt 2 lt oe 7 e You can set the output voltage to any value between 12 Vdc and 12 Vdc in 1 mV steps Each DAC is earth referenced it cannot float e Each DAC channel is capable of supplying 10 mA maximum current Note You must limit the output current to 40 mA total for all three slots six DAC channels e To maintain the rated output accuracy the load RL in the diagram shown above must be greater than 1 KQ 397 Chapter 8 Tutorial Multifunction Module DAC Errors The output of a DAC varies with temperature If possible you should operate the instrument at a stable temperature and as close as possible to the calibration temperature of the DAC for greater accuracy The output of a DAC also exhibits two other types of errors differential error and integral error e Differential Error refers to the smallest possible change in voltage The DAC output is not linear but is stepped as progressively larger or smaller voltages are programmed The step size is 1 mV e Integral Error refers to the difference between the programmed voltage and the actual output voltage from the DAC This error is included in the output specifications shown on page 412 j Differential Error Vout Integral Error Vprogrammed 398 Chapter 8 Tutorial Relay Life and Preventative Maintenance
390. sembly 5 28 G gage factor strain 374 gain M Mx B 39 119 gate signal totalizer 135 396 gauge wire size 336 GET Group Execute Trigger 82 GP IB address address selection 46 151 cable 51 connector 5 interface selection 46 151 setting address 150 factory address setting 150 ground loops 337 341 grounding 337 H half digit 100 416 handle adjusting 29 removing 29 handshake RS 232 DTR DSR mode 153 factory setting 47 153 Modem mode 154 None no flow mode 153 RTS CTS mode 153 selecting 47 153 XON XOFF mode 153 hardware output lines alarms 128 hardware rack mounting 31 high frequency switching 390 HP 34901A module channel numbering 164 description 164 screw terminal diagram 165 simplified schematic 164 wiring log 165 module overview 7 164 module specifications 409 HP 34902A module channel numbering 166 description 166 screw terminal diagram 167 simplified schematic 166 wiring log 167 module overview 7 166 module specifications 409 HP 34903A module channel numbering 168 description 168 384 screw terminal diagram 169 simplified schematic 168 wiring log 169 module overview 8 168 module specifications 409 RC protection circuitry 385 snubber circuitry 385 HP 34904A module channel numbering 170 combining matrices 389 description 170 388 module overview 8 170 module specifications 409 screw terminal diagram 171 simplified sche
391. st enter the information in the modules exactly as shown or an error will be generated If several system errors occur while attempting to run a macro you may have to reboot your PC to get the HP IB port to work properly Note To use these examples with Windows 3 1 you will need to modify the declarations at the top of the Port Configuration module Change visa32 dll to visa dll in all declarations 321 Chapter 7 Application Programs Example Programs for Excel 7 0 Excel 7 0 Example takeReadings Macro HP 34902A or HP 34908A multiplexer modules When this subroutine is executed it will code in the section titled SET UP Note that you must have one of the above modules installed in slot 100 for this program to run properly You must also have an HP IB interface card installed in your PC with the VISA or VTL library Option Explicit Sub takeReadings This Excel Macro Visual Basic configures the HP 34970A for scanning with the HP 34901A take the specified number of readings on the selected channel You can easily modify the number of readings channel delay and channel number To make these changes modify the Columns 1 ClearContents Columns 2 ClearContents Dim I As Integer Dim numberMeasurements As Integer Dim measurementDelay As Single Dim points As Integer Used for counter in For Next loop Number of readings Delay between relay closure and measurement VU Pr
392. st potential in the system It is recommended that you use wire with 600 V rated insulation 335 Chapter 8 Tutorial System Cabling and Connections e Cable Resistance Varies with wire gauge size and cable length Use the largest gauge wire possible and try to keep the cable lengths as short as possible to minimize the cable resistance The following table lists typical cable resistance for copper wire of several gauge sizes the temperature coefficient for copper wire is 0 35 per C Q ft 2 conductors AWG at 25 C 14 5 mQ 16 10 mQ 18 15 mQ 20 20 ma 22 30 MQ 24 50 ma Recommended wire size for the screw terminals on HP 34970A plug in modules e Cable Capacitance Varies with the insulation type cable length and cable shielding Cables should be kept as short as possible to minimize cable capacitance In some cases low capacitance cable can be used The table below lists typical cable specifications Cable Type Nominal Impedance Capacitance Attenuation Twisted Pair 1009 at 1 MHz 10 to 20 pF ft Up to 1 dB 100 ft at 1 MHz Shielded Twisted Pair 1009 at 1 MHz 10 to 20 pF ft Up to 1 dB 100 ft at 1 MHz Coaxial 509 or 752 at 100 MHz 15 to 25 pF ft Up to 6 dB 100 ft at 100 MHz Twisted Pair Ribbon 1002 at 1 MHz 15 to 20 pFift Up to 1 dB 100 ft at 1 MHz 336 Chapter 8 Tutorial System Cabling and Connections Grounding Techniques One pur
393. stem Overview Alarm Limit Commands OUTPut ALARm 1 2 3 4 SOURce lt ch_list gt ALARm 1 2 3 4 SOURce Assign the alarm number to report any alarm conditions on the specified channels If not assigned all alarms on all channels are reported on Alarm 1 by default The SOUR query returns a list of channel numbers in the SCPI definite length block format The response begins with the character followed by a single character representing the number of succeeding characters to interpret as a length specifier followed by a length specifier representing the number of bytes in the block followed by a block of that many bytes An empty scan list one with no channels selected will be 13 For example if you send OUTP ALARM1 SOUR 101 103 the OUTP ALARM1 SOUR command will return the following 214 101 102 103 CALCulate LIMit UPPer lt value gt lt ch_list gt LIMit UPPer lt ch_list gt Set the upper limit for alarms on the specified channels You can set the value to any number between 120 and 120 of the highest range for the present function The default upper limit is 1 0E 15 The lower limit must always be less than or equal to the upper limit The UPP query returns the upper limit for alarms on the specified channels CALCulate LIMit UPPer STATe OFF ON lt ch_list gt LIMit UPPer STATe lt ch_list gt Disable or enable the upper alarm limi
394. ster bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved e Each time you start a new scan the instrument clears all readings including alarm data stored in reading memory from the previous scan Therefore the contents of memory are always from the most recent scan e Theinstrument clears all readings in memory after a Factory Reset RST command or Instrument Preset SySTem PRESet command Reading memory is not cleared when you read it e While a scan is running the instrument automatically stores the minimum and maximum readings and calculates the average for each channel You can read these values at any time even during a scan e Each reading is stored with measurement units time stamp channel number and alarm status information F rom the remote interface you can specify which information you want returned with the readings from the front panel all of the information is available for viewing For more information see Reading Format on page 87 90 Chapter 4 Features and Functions Scanning e Readings acquired during a Monitor are not stored in memory however all readings from a scan in progress at the same time are stored in memory e TheMEASure and READ commands send readings directly to the instrument s output buffer but readings are not stored in memory You will not be able to view these readings e The INITiate command
395. surement on the channel The programmed channel delay overrides the default channel delay that the instrument automatically adds to each channel Scan List Va E Chi Ch2 Ch3 Ch4 Ch5 Ch6 z AU t e V Channel Delay e You can set the channel delay to any value between 0 seconds and 60 seconds with 1 ms resolution Y ou can select a different delay for each channel The default channel delay is automatic the instrument determines the delay based on function range integration time and ac filter setting see Automatic Channel Delays on the next page e The MEASure and CONFigure commands set the channel delay to automatic A Factory Reset RST command also sets the channel delay to automatic e Front Panel Operation CH DELAY TIME e Remote Interface Operation The following command adds a 2 second channel delay to channe 101 ROUT CHAN DELAY 2 101 88 Chapter 4 Features and Functions Scanning Automatic Channel Delays If you do not specify a channel delay the instrument selects a delay for you The delay is determined by function range integration time and ac filter setting as shown below DC Voltage Thermocouple DC Current for all ranges Integration Time Channel Delay PLC gt 1 2 0 ms PLC lt 1 1 0 ms Resistance RTD Thermistor 2 and 4 wire Channel Dela Channel Delay Range For PLC gt 1 Range
396. t character in unit name For Mx B scaling you can specify a custom label with up to three characters The first character must be a letter or the character the character is allowed only as the leftmost character in the label The remaining two characters can be letters numbers or an underscore Not able to perform on more than one channel You can perform this operation on only one channel at a time Check the channel list that you sent with this command to see if it contains more than one channel This error is generated by the ROUTe MON and DATA LAST commands Not able to recall state it is empty You can only recall a state from a location that contains a previously stored state The state location that you attempted to recall is empty The storage locations are numbered 0 through 5 Not able to recall state DMM enable changed The enable disable state of the internal DMM has been changed since the instrument state was stored Use the INSTrument DMM command to determine the state of the internal DMM For more information see Internal DMM Disable on page 145 Module currently committed to scan When you add a multiplexer channel to a scan list that entire module is dedicated to the scan You cannot perform low level close or open operations on any channels on that module even those channels that are not configured To stop a scan in progress send the ABORt command or a bus Device Clear 311
397. t is TC The TYPE query returns the current temperature transducer type on the specified channels Returns TC RTD FRTD or THER SENSe TEMPerature NPLC 0 02 0 2 1 2 10 20 100 200 MIN MAX lt ch_list gt Set the integration time in number of power line cycles PLCs on the specified channels The default is 1 PLC MIN 0 02 MAX 200 For more information on the relationship between integration time measurement resolution number of digits and number of bits see the table on page 203 For more information on time refer to Custom A D Integration Time in chapter 4 starting on page 103 219 Chapter 5 Remote Interface Reference Temperature Configuration Commands Thermocouple Commands SENSe TEMPerature TRANsducer TCouple TYPE B E J K N R S T lt ch_list gt TCouple TYPE lt ch_list gt Select the thermocouple type to use on the specified channels The default is a J Type thermocouple The TYPE query returns the thermocouple type currently in use Returns B E J K N R S or SE SENSe TEMPerature TRANsducer TCouple RJUNction TYPE INTernal EXTernal FIXed lt ch_list gt RJUNction TYPE lt ch_list gt Thermocouple measurements require a reference junction temperature For the reference junction temperature you can use an internal measurement on the module an ex
398. t may be degraded for the selected range Typically an additional 0 01 of range error may be introduced This additional error will remain until the next periodic removal typically 15 minutes 366 Chapter 8 Tutorial Measurement Fundamentals Current Measurements Current measurements are allowed only on the HP 34901A module An ammeter senses the current flowing through its input connections approximating a short circuit between its input terminals An ammeter must be connected in series with the circuit or device being measured such that current flows through both the meter and the test circuit A resistor R in the diagram below is connected across the input terminals such that a voltage drop proportional to the input current is generated The value of R is selected as low as possible to minimize the instrument s burden voltage or IR drop This voltage drop is sensed by the internal DMM and scaled to the proper current value to complete the measurement see the discussion on the following page On Card S1 aes Vdc to Input Amplifi d E Vdc to Input Amplifier an 10 ONO Analog to Digital Converter Rs LO AC current measurements are very similar to de current measurements The output of the current to voltage sensor is measured by an ac voltmeter The input terminals are direct coupled ac dc coupled to the shunt so that the internal DMM maintains de continuity in the test circuit Performing ac cu
399. t number 100 200 or 300 and the two digits on the right indicate the channel number 102 110 etc Note You can use and D to skip to the beginning of the previous or next slot For this example assume that you have the HP 34901A multiplexer installed in slot 100 and select channel 103 Select the measurement parameters for the selected channel Use the knob to scroll through the measurement choices on each level of the menu When you press to make your selection the menu automatically guides you through all relevant choices to configure a measurement on the selected function When you have finished configuring the parameters you are automatically exited from the menu The current selection or default is displayed in full bright for easy identification When you make a different selection the new choice is shown in full bright and it becomes the default selection The order of the choices always remains the same however you always enter the menu at the current full bright setting for each parameter Note The menu will timeout after about 20 seconds of inactivity and any changes made previously will take effect For this example configure channel 103 to measure a J type thermocouple with 0 1 C of display resolution 23 Chapter 1 Quick Start To Configure a Channel for Scanning Note Press to sequentially step through the scan list and take a measurement on each channel readings are not stored in
400. t on the specified channel The STAT query returns the state of the upper alarm on the specified channels Returns 0 OFF or 1 ON 250 Chapter 5 Remote Interface Reference Alarm System Overview CALCulate LIMit LOWer lt value gt lt ch_list gt LIMit LOWer lt ch_list gt Set the lower limit for alarms on the specified channels You can set the value to any number between 120 and 120 of the highest range for the present function The default lower limit is 1 0E 15 The lower limit must always be less than or equal to the upper limit The Low query returns the lower limit for alarms on the specified channels CALCulate LIMit LOWer STATe OFF ON lt ch_list gt LIMit LOWer STATe lt ch_list gt Disable or enable the lower alarm limit on the specified channel The STAT query returns the state of the lower alarm on the specified channels Returns 0 OFF or 1 ON SYSTem ALARm Read the alarm data from the alarm queue one alarm event is read and cleared each time this command is executed The following is an example of an alarm stored in the alarm queue if no alarm data is in the queue the command returns 0 for each field 3 10090000E 01 C 1997 05 01 14 39 40 058 101 2 1 1 Reading with Units 31 009 C 4 Channel Number 2 Date May 1 1997 5 Limit Threshold Crossed 0 No Alarm 3 Time 2 39 40 058 PM 1 LO 2 Hl
401. tems Meosure TEMPERATURE Pp THERMISTOR To select the thermistor type for the active channel choose from the following items TYPE 2 2 KOHM TYPE 5 KOHM TYPE 10 KOHM e Remote Interface Operation You can use the MEASure or CONF igure command to select the probe type and thermistor type For example the following statement configures channel 301 for measurements of a 5 kQ thermistor CONF TEMP THER 5000 301 You can also use the SENSe command to select the probe type and thermistor type For example the following statement configures channel 103 for measurements of a 10 kQ thermistor SENS TEMP TRAN THERM TYPE 10000 103 112 Chapter 4 Features and Functions Voltage Measurement Configuration Voltage Measurement Configuration To connect voltage sources to the module s screw terminals see page 21 This section contains information to help you configure the instrument for making voltage measurements The instrument can measure dc and true RMS ac coupled voltages on the measurement ranges shown below 1oomv 1v 10v 100v 300v Autorange DC Input Resistance Normally the instrument s input resistance is fixed at 10 MQ for all dc voltage ranges to minimize noise pickup To reduce the effects of measurement loading errors you can set the input resistance to greater than 10 Ga for the 100 mVdc 1 Vdc and 10 Vdc ranges
402. terface 47 Chapter 2 Front Panel Overview To Store the Instrument State To Store the Instrument State You can store the instrument state in one of five non volatile storage locations A sixth storage location automatically holds the power down configuration of the instrument When power is restored the instrument can automatically return to its state before power down a scan in progress before power down will also be resumed 1 Select the storage location From the front panel you have the ability to assign names up to 12 characters to each of the five stored states NAME STATE The storage locations are numbered 1 through 5 The power down state is automatically stored and can be recalled from the front panel the state is named LAST PWR DOWN STORE STATE 2 STATEC 2 Store the instrument state The instrument stores all channel configurations alarm values scaling values scan interval setups and advanced measurement configurations CHANGE SAVED A 8 System Overview Computer and Software System Overview This chapter provides an overview of a computer based system and describes the parts of a data acquisition system This chapter is divided into the following sections e Data Acquisition System Overview see below e Signal Routing and Switching starting on page 57 e Measurement Input starting on page 60 e Control Output starting on page 67 Data Acquisiti
403. terface you can write to both ports simultaneously e From the front panel only you can specify whether you want to use binary or decimal format Once you have selected the number base it is used for all input or output operations on the same port e A Factory Reset RST command Instrument Preset SySTem PRESet command and Card Reset SySTem CPON command from the remote interface will reconfigure both ports as input ports Note that a from the front panel resets only the port currently selected both ports are not reset e Front Panel Operation After selecting the output port press to edit the bit pattern or decimal value the least significant bit is on the right Press again to output the bit pattern To cancel an output operation in progress wait for the display to time out From the front panel only you can specify whether you want to use binary or decimal format USE DECIMAL USE BINARY e Remote Interface Operation From the remote interface you can output an 8 bit byte to one port or a 16 bit word to both ports simultaneously using the following commands Y ou must specify a decimal value binary data is not accepted If you are going to read both ports simultaneously you must send the command to port O1 SOUR DIG DATA BYTE 10 302 Write to port 02 SOUR DIG DATA WORD 10327 301 Write to both ports 138 Chapter 4 Features and Functions DAC Output Operations DAC Ou
404. teristics These include measurement resolution reading speed and the ability to reject spurious noise There are several analog to digital conversion techniques but they can be divided into two types integrating and non integrating The integrating techniques measure the average input value over a defined time interval thus rejecting many noise sources The non integrating techniques sample the instantaneous value of the input plus noise during a very short interval The internal DMM uses an integrating ADC technique You can select the resolution and reading speed from 6 digits 22 bits at 3 readings per second to 4 digits 16 bits at up to 600 readings per second The Advanced menu from the HP 34970A front panel allows you to control the integration period for precise rejection of noise signals 61 Chapter 3 System Overview Measurement Input Main Processor The main processor located in the floating logic section controls the input signal conditioning ranging and the ADC The main processor accepts commands from and sends measurement results to the earth referenced logic section The main processor synchronizes measurements during scanning and control operations The main processor uses a multi tasking operating system to manage the various system resources and demands The main processor also calibrates measurement results performs Mx B scaling monitors alarm conditions converts transducer measurements to engineerin
405. ternal thermistor or RTD measurement or a known fixed junction temperature The default is INTernal The TYPE query returns the source currently selected Returns INT EXT or FIX e f you select an external reference the instrument automatically reserves channel 01 on the multiplexer in the lowest slot as the reference channel thermistor or RTD measurement If you have more than one multiplexer installed channel 01 on the module in the lowest slot is used as the reference for the entire instrument e Before configuring a thermocouple channel with an external reference you must configure the reference channel channel 01 for a thermistor or RTD measurement An error is generated if you attempt to select the external reference source before configuring the reference channel An error is also generated if you change the function on the reference channel after selecting the external reference for a thermocouple channel 220 Chapter 5 Remote Interface Reference Temperature Configuration Commands SENSe TEMPerature TRANsducer TCouple CHECk OFF ON lt ch_list gt TCouple CHECk lt ch_list gt Disable or enable the thermocouple check feature to verify that your thermocouples are properly connected to the screw terminals for measurements If you enable this feature the instrument measures the channel resistance after each thermocouple measurement to ensure a proper connection If
406. tery 309 221 222 223 224 225 226 251 Chapter 6 Error Messages Instrument Errors Settings conflict calculate limit state forced off If you plan to use scaling on a channel which will also use alarms be sure to configure the scaling values first This error is generated if you attempt to assign the alarm limits first and the instrument will turn off alarms and clear the limit values Settings conflict module type does not match stored state Before recalling a stored state the instrument verifies that the same module types are installed in each slot The instrument has detected a different module type in one or more slots Settings conflict trig source changed to IMM This error is generated if you attempt to set the channel advance source ROUTe CHAN ADVance SOURce command to the same source used for the scan trigger TRIGger SOURce command The command has been accepted and executed but the scan trigger source is reset to IMMediate Settings conflict chan adv source changed to IMM This error is generated if you attempt to set the scan trigger source TRIGger SOURce command to the same source used for the channel advance source ROUTe CHAN ADVance SOURce command The command has been accepted and executed but the channel advance source is reset to IMMediate Settings conflict DMM disabled or missing This command is valid only when the internal DMM is installed and enabled Use
407. the following item 4W SCAN e Remote Interface Operation The following program segment configures the instrument for an externally controlled scan TRIG SOUR TIMER Select the scan interval ROUT CHAN ADV SOUR EXT Select the channel advance source RIG TIMER 5 Set the scan interval to 5 seconds TRIG COUNT 2 Sweep the scan list 2 times INIT Initiate the scan To configure the instrument for 4 wire external scanning send the following command ROUTe CHANnel FWIRe OFF ON lt ch_list gt 97 Chapter 4 Features and Functions General Measurement Configuration General Measurement Configuration This section contains general information to help you configure the instrument for making measurements during a scan Since these parameters are used by several measurement functions the discussion is combined into one common section Refer to the later sections in this chapter for more information on parameters that are specific to a particular measurement function Note It is important that you select the measurement function before selecting other parameters on a given channel When you change the function on a channel all other settings range resolution etc are reset to their default values Measurement Range You can allow the instrument to automatically select the measurement range using autoranging or you can select a fixed range using manual ranging Autoranging is convenient because the instru
408. the INSTrument DMM command to determine the state of the internal DMM For more information see Internal DMM Disable on page 145 Settings conflict DMM enabled When the internal DMM is enabled the ROUTe CHAN ADVance SOURce and ROUTe CHAN FWIRe commands are not allowed Use the INSTrument DMM command to determine the state of the internal DMM For more information see Internal DMM Disable on page 145 Unsupported temperature transducer type An invalid RTD or thermistor type has been specified The following RTDs are supported a 0 00385 85 and a 0 00391 91 The following thermistors are supported 2 2 KQ 2252 5 kQ 5000 and 10 kQ 10000 Example CONF TEMP RTD 1 101 310 261 271 272 281 291 292 301 Chapter 6 Error Messages Instrument Errors Not able to execute while scan initiated While a scan is running you cannot change any parameters that affect the scan channel configuration scan interval scaling values alarm limits issue a Card Reset or recall a stored state To stop a scan in progress send the ABORt command or a bus Device Clear Not able to accept unit names longer than 3 characters For Mx B scaling you can specify a custom label with up to three characters You can use letters A Z numbers 0 9 an underscore _ or the character which displays a degree symbol on the front panel Not able to accep
409. the display is disabled e The display is automatically enabled when power is cycled after a Factory Reset RST command or when you go to local by pressing e You can display a message on the front panel by sending a command from the remote interface The instrument can display up to 13 characters on the front panel if you attempt to send more than 13 characters an error is generated Y ou can use letters A Z numbers 0 9 and special characters like x etc Use the character to display a degree symbol Commas periods and semicolons share a display space with the preceding character and are not considered individual characters While a message is displayed on the front panel readings from a scan or monitor are not sent to the display e Sending a message to the display from the remote interface overrides the display state this means that you can display a message even if the display is turned off e Remote Interface Operation The following command turns off the front panel display DISPLAY OFF The following command displays a message on the front panel and turns on the display if disabled DISP TEXT SCANNING To clear the message displayed on the front panel without changing the display state send the following command DISPLAY TEXT CLEAR 144 Chapter 4 Features and Functions System Related Operations Real Time System Clock During a scan
410. the enable register to be reported to the Status Byte register you must write a decimal value which corresponds to the binary weighted sum of the corresponding bits 275 Chapter 5 Remote Interface Reference The SCPI Status System HP 34970A Status System NOTES C Condition Register EV Event Register Questionable Data Register Alarm Register EN Enable Register Ovld Overload EN Queue Cc EV EN Ovfl Overflow Volt Ovid lt 1 gt 1 0 Alarm 1 0 lt 1 gt Curr Ovid lt 2 gt 2 1 Alarm 2 1 lt 2 gt lt 4 gt 2 Alarm 3 2 lt 4 gt lt 8 gt e 3 Alarm 4 3 lt 8 gt lt 16 gt gt 4 Queue 4 lt 16 gt lt 32 gt 5 Alrm Ovfl 5 lt 32 gt lt 64 gt OR OR lt 128 gt fi lt 256 gt Res Ovid lt 512 gt Temp Ovid lt 1024 gt Tot Ovfl lt 2048 gt e e Mem Ovfl lt 4096 gt lt 8192 gt lt 16384 gt 19 NOT USED 20 ey 15 15 NOT USED STAT QUES COND SYST ALARm STAT ALARm COND STAT QUES EVENt STAT ALARm EVENt STAT QUES ENABle lt
411. the gain and offset values are not cleared If you decide to add a channel back to the scan list without changing the function the original gain and offset values are restored and scaling is turned back on This makes it easy to temporarily remove a channel from the scan list without entering the scaling values again e A Factory Reset RST command turns off scaling and clears the scaling values on all channels An Instrument Preset SySTem PRESet command or Card Reset SySTem CPON command does not clear the scaling values and does not turn off scaling 244 Chapter 5 Remote Interface Reference Mx B Scaling Overview Mx B Scaling Commands CALCulate SCALe GAIN lt gain gt lt ch_list gt SCALe GAIN lt ch_list gt Set the gain M for scaled readings on the specified channels The maximum gain allowed is 1E 15 The default is M 1 The GAIN query returns the gain value on the specified channels CALCulate SCALe OFFSet lt offset gt lt ch_list gt SCALe OFFSet lt ch_list gt Set the offset B for scaled readings on the specified channels The maximum offset allowed is 1E 15 The default is B 0 The OFFS query returns the offset value on the specified channels CALCulate SCALe UNIT lt quoted_string gt lt ch_list gt SCALe UNIT lt ch_list gt Specify the custom label e g RPM PSI for scaled measurements on the specified channels
412. the scan list Scan Count 1 to 50 000 scans or continuous A Scan List 1 sweep m LHN Scan to Scan Interval 0 to 99 59 59 hours e You can manually control a scan by repeatedly pressing from the front panel e You can start a scan by sending a software command from the remote interface e You can start a scan when an external TTL trigger pulse is received e You can start a scan when an alarm condition is logged on the channel being monitored 63 Chapter 3 System Overview Measurement Input Scanning With External Instruments If your application doesn t require the built in measurement capabilities of the HP 34970A you can order it without the internal DMM In this configuration you can use the HP 34970A for signal routing or control applications If you install a multiplexer plug in module you can use the HP 34970A for scanning with an external instrument You can connect an external instrument such as a DMM to the multiplexer COM terminal H SN L S oS H Se Liges External DMM Input o z omenet E H C T inal ommon terminals ZH ENO TA oL To control scanning with an external instrument two control lines are provided When the HP 34970A and the external instrument are properly configured you can synchronize a scan sequence between the two Channel Closed OUT Ext Trig IN HP 34970A External DMM Sp
413. the scan list the internal DMM is not required either The count on a totalizer channel is not reset when it is being monitored the Monitor ignores the totalizer reset mode 93 Chapter 4 Features and Functions Single Channel Monitoring e IntheAlarm Scan configuration see Scanning on Alarm on page 84 the instrument sweeps the scan list once each time a reading crosses an alarm limit on a channel In this configuration you may use the Monitor function to continuously take readings on a selected channel and wait for an alarm on that channel The monitored channel can be part of the scan list but you can also use a channel on the multifunction module which does not have to be part of the scan list and you do not have to use the Monitor function e Front Panel Operation To start a Monitor press Turn the knob to advance to the desired channel The instrument begins monitoring after you pause for a few seconds on a configured channel Tostop a Monitor press again Note that while the instrument in in the remote mode you can still turn on the Monitor function and select the desired channel Remote Interface Operation The following program segment selects the channel to be monitored specify only one channel and enables the Monitor function ROUT MON 101 ROUT MON STATE ON Toread the monitor data from the selected channel send the following command This command returns the reading only the units time
414. ting 150 humidity product operating 408 I ice bath 348 JEEE 488 HP IB address selection 46 151 cable 51 connector 5 interface selection 46 151 setting address 150 factory address setting 150 impedance mismatching 391 INITiate command description 79 204 230 example 206 injected current dc voltage 356 input resistance dc loading errors 357 de voltage 118 114 357 INPut IMP AUTO command 114 223 insertion loss 391 411 installing BenchLink Data Logger software 18 module into mainframe 20 instrument preset state 161 instrument state storage definition 48 front panel operation 141 naming states 48 140 power down recall 140 remote operation 141 INST DMM command 243 267 INST DMM INST command 243 267 integral error DAC 398 integrating ADC 61 integration time command syntax 218 definition 103 selecting 103 vs channel delays 89 vs normal mode rejection 405 vs number of bits 103 203 vs number of digits 103 203 vs reading speed 405 407 vs resolution 103 203 interface HP IB IEEE 488 address selection 46 151 cable 51 connector 5 interface selection 46 151 setting address 150 factory address setting 150 interface RS 232 serial baud rate 47 cable 51 flow control 47 parity 47 stop bits 47 Interface key 36 46 151 internal DMM block diagram 343 field installation kit See Option 001 Installation Note enabling dis
415. ting on page 181 e Simplified Programming Overview starting on page 201 e The MEASure and CONFigure Commands starting on page 207 e Setting the Function Range and Resolution starting on page 214 e Temperature Configuration Commands starting on page 219 e Voltage Configuration Commands on page 223 e Resistance Configuration Commands on page 224 e Current Configuration Commands on page 224 e Frequency Configuration Commands on page 225 e Scanning Overview starting on page 226 e Single Channel Monitoring Overview starting on page 237 e Scanning With an External Instrument starting on page 239 e Mx B Scaling Overview starting on page 244 e Alarm System Overview starting on page 247 e Digital Input Commands on page 255 e Totalizer Commands starting on page 256 e Digital Output Commands on page 258 e DAC Output Commands on page 258 e Switch Control Commands on page 259 e State Storage Commands on page 261 e System Related Commands starting on page 264 e Interface Configuration Commands on page 269 e RS 232 Interface Configuration on page 270 e Modem Communications on page 274 e The SCPI Status System starting on page 275 e Status System Commands starting on page 286 e Calibration Commands starting on page 292 e Service Related Commands starting on page 294 e An Introduction tothe SCPI Language starting on page 296 e Using Device Clear on page 302 If you are a first time user of the SCPI language
416. tion measurements are traceable to the United States National Institute of Standards and Technology formerly National Bureau of Standards to the extent allowed by that organiza tion s calibration facility and to the calibration facilities of other Interna tional Standards Organization members Warranty This HP product is war ranted against defects in materials and workman ship for a period of three years from date of shipment Duration and conditions of warranty for this product may be superceded when the product is integrated into becomes a part of other HP products During the warranty period HP will at its option either repair or replace products which prove to be defective For warranty information on HP BenchLink Data Logger refer to the on line warranty statements Warranty Service For warranty service or repair this product must be returned to a service facility designated by HP For products returned to HP for warranty service the Buyer shall prepay shipping charges to HP and HP shall pay shipping charges to return the product to the Buyer However the Buyer shall pay all shipping charges duties and taxes for products returned to HP from another country Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Buyer Buyer supplied products or interfacing un authorized modification or misuse operation
417. to ground through the internal DMM voltage errors are generated along the distributed resistance of the thermocouple wire Adding a shield to the thermocouple wire will shunt the common mode noise to earth ground and preserve the measurement Power Line Distributed PFC lf Cif CO Capacitance Cy Or na oe HI R R R R R R N Nv AW AWN LO Distributed Pb Resistance WITHOUT SHIELD W DMM WITH SHIELD gt DMM Common mode noise can dramatically affect the internal DMM A typical thermocouple output is a few millivolts and a few millivolts of common mode noise can overload the input to the internal DMM Calculation Error An error is inherent in the way a thermocouple voltage is converted to a temperature These calculation errors are typically very small compared to the errors of the thermocouple wiring connections and reference junction see page 345 353 Chapter 8 Tutorial Measurement Fundamentals DC Voltage Measurements To make a useful de meter a front end is required to condition the input before the analog to digital conversion Signal conditioning increases the input resistance amplifies small signals and attenuates large signals to produce a selection of measuring ranges Signal Conditioning for DC Measurements Input signal conditioning for dc voltage measurements includes both amplification and attenuation A s
418. to the internal DMM and or Com at a time connecting one channel will close the other thus shorting the input I to LO e If any channels are configured to be part of the scan list you cannot close multiple channels closing one channel will open the previously closed channel 164 Chapter 4 Features and Functions HP 34901A 20 Channel Multiplexer I WIRING LOG Slot Number 0100 0200 300 EH Function Comments aa 250 NTD ES 3 mo za SES 4g Sig OF ASB Ss gn X Or a e S ER m 11 E 12 Sks 13 OTR 14 SA 15 SH ogo 16 San g i L 8 ze i 18 S z 5 19 OA 20 S H COM S i L COM rp noer Current Channels Only ls s 2 SH n 22 SE 3 E 5 on X 4W Sense Channels are paired to Channel n 10 a E S ES 5 F S iz g 5 Refer to the diagrams on page 20 to connect wiring to the module CSR i amp SES A Maximum Input Voltage 300 V CAT I EO AWG Typical 3 3 D Maximum Input Current 1 A et 3 g Maximum Switching Power 50 W 6 mm Sez i HE O 3 O AN AE Z WARNING To prevent electric
419. tput Operations The multifunction module HP 34907A has two low noise analog outputs capable of outputting calibrated voltages between 12 volts with 16 bits of resolution Each DAC Digital to Analog Converter channel can be used as a programmable voltage source for analog input control of other devices On the multifunction module the DAC channels are numbered s04 and s05 wheres represents the slot number You can set the output voltage to any value between 12 Vdc and 12 Vdc in 1 mV steps Each DAC is earth referenced it cannot float Each DAC channel is capable of 10 mA maximum output current Note You must limit the output current to 40 mA total for all three slots six DAC channels A Factory Reset RST command Instrument Preset SySTem PRESet command and Card Reset SySTem CPON command from the remote interface will reset both DACs to 0 Vdc Note that a from the front panel resets only the DAC currently selected both channels are not reset Front Panel Operation After selecting the desired DAC press to edit the output voltage Press again to output the specified voltage from the DAC channel Remote Interface Operation The following command outputs 2 5 Vdc from the DAC on channel 05 SOURCE VOLT 2 5 305 139 Chapter 4 Features and Functions System Related Operations System Related Operations This section gives information on system related topics such as stori
420. ts the cycles on each relay in the instrument and stores the total count in non volatile memory on each switch module You can use this feature on any of the relay modules and the internal DMM e n addition tothe channel relays you can also query the count on backplane relays and bank relays Note that you cannot control the state of these relays from the front panel but you can query the count For more information on channel numbering and layout refer to Module Overview starting on page 163 e You can also query the state of the three relays on the internal DMM These relays are numbered 1 2 and 3 These relays open or close when a function or range is changed on a module e TheHP 34908A multiplexer contains 40 channels which are switched HI only using only 20 relays Each relay is used to switch HI on two different channels and only one channel can be closed at a time The channels are arranged such that channe s 01 and 21 use different contacts on the same relay The remaining channels are also paired in the same manner channels 02 and 22 channels 03 and 23 etc Therefore when you query the relay count on a channel the number reflects the number of times that the relay was dosed For example the relay count will always be the same on channels 01 and 21 e You can reset the count allowed only from remote but the instrument must be unsecured see Calibration Overview on page 155 to unsecure t
421. u can manually clear the output lines at any time even during a scan and the alarm data in memory is not cleared however data is cleared when you initiate a new scan The alarm outputs are also cleared when you initiate a new scan 128 Chapter 4 Features and Functions Alarm Limits e You can control the slope of the pulse from the alarm outputs the selected configuration is used for all four outputs In the falling edge mode OV TTL low indicates an alarm In the rising edge mode 5V TTL high indicates an alarm A Factory Reset RST command will reset the slope to falling edge y A Falling Edge Rising Edge Note Changing the slope of the output lines may cause the lines to change state e Front Panel Operation To specify if you want to manually clear all four alarm outputs choose from the following items DO NOT CLEAR CLEAR OUTPUTS To select the output configuration for all four output lines choose from the following items LATCH ON FAIL TRACK PASS F To configure the slope of all four output lines choose from the following items FAIL HIGH FAIL LOW e Remote Interface Operation To clear the specified output lines or to clear all four lines use one of the following commands OUTPUT OUTPUT LARM2 CLEAR Clear alarm output line 2 ARM CLEAR ALL Clear all four alarm outputs A A To select the output configuration for all four output lines
422. uest SRQ when alarms are generated See The SCPI Status System starting on page 275 for more information e The default values for the upper and lower alarm limits are 0 The lower limit must always be less than or equal to the upper limit even if you are using only one of the limits 124 Chapter 4 Features and Functions Alarm Limits e For details on configuring alarms on the multifunction module see Using Alarms With the Multifunction Module on page 130 e A Factory Reset RST command clears all alarm limits and turns off all alarms An Instrument Preset SySTem PRESet command or Card Reset SYSTem CPON command does not clear the alarm limits and does not turn off alarms e Front Panel Operation To select the alarm for use on the active channel choose from the following items m NO ALARM USE ALARM 1 USE ALARM 4 Then choose from the following alarm conditions HI LO ALARMS HI ALARM ONLY LO ALARM ONLY Then set the desired limit values and exit the menu Note that the instrument does not start evaluating the alarm conditions until you exit the Alarm menu e Remote Interface Operation To assign the alarm number to report any alarm conditions on the specified channels use the following command if not assigned all alarms on all channels are reported on Alarm 1 by default OUTPUT ALARM2 SOURCE 103 212 To set the upper and lower alarm limits on the s
423. uffer is almost full approximately 100 characters and releases the line when space is available again 153 Chapter 4 Features and Functions Remote Interface Configuration e Modem This mode uses the DTR DSR and RTS CTS lines to control the flow of data between the instrument and a modem When the RS 232 interface is selected the instrument sets the DTR line true The DSR line is set true when the modem is on line The instrument sets the RTS line true when it is ready to receive data The modem sets the CTS line true when it is ready to accept data The instrument sets the RTS line false when the input buffer is almost full approximately 100 characters and releases the line when space is available again e For moreinformation on using the RS 232 interface refer to RS 232 Interface Configuration starting on page 270 e The flow control selection is stored in non volatile memory and does not change when power has been off after a Factory Reset RST command or after an Instrument Preset SySTem PRESet command e Front Panel Operation FLOW RTS CTS 154 Chapter 4 Features and Functions Calibration Overview Calibration Overview This section gives a brief introduction to the calibration features of the instrument and plug in modules For a more detailed discussion of the calibration procedures see chapter 4 in the HP 34970A Service Guide Calibration Security This feature allows you to enter
424. umber of front panel key presses or scan trigger commands that will be accepted before terminating the scan See Scan Count on page 86 for more information e Mx scaling and alarm limits are applied to measurements during a Scan Once operation and all data is stored in non volatile memory e Front Panel Operation Interval MANUAL SCAN To initiate the scan and store all readings in memory press The ONCE annundiator turns on as a reminder that a Scan Once operation is in progress Note Tostop ascan press and hold e Remote Interface Operation The following program segment configures the instrument for a Scan Once operation TRIG SOURCE BUS Select the bus once configuration TRIG COUNT 2 Sweep the scan list 2 times INIT Initiate the scan Then send the TRG trigger command to begin each scan sweep You can also trigger the instrument from the HP IB interface by sending the EEE 488 Group Execute Trigger GET message The following statement shows how tosend a GET using HP BASIC TRIGGER 709 Group Execute Trigger Note To stop a scan send the ABORt command 82 Chapter 4 Features and Functions Scanning External Scanning n this configuration the instrument sweeps through the scan list once each time a low going TTL pulse is received on the rear panel Ext Trig Input line pin 6 Ext Trig Input Gnd Ext Trig Connector e You can specify a scan count which sets the nu
425. ure The internal DMM measures the resistance of the thermistor and then calculates the equivalent temperature Thermistors have a higher sensitivity than thermocouples or RTDs This makes a thermistor a good choice when measuring very small changes in temperature Thermistors are however very non linear especially at high temperatures and function best below 100 C Because of their high resistance thermistors can be measured using a 2 wire measurement method The internal DMM supports 2 2 kQ 44004 5 kQ 44007 and 10 kQ 44006 thermistors 346 Chapter 8 Tutorial Measurement Fundamentals Thermocouple Measurements A thermocouple converts temperature to voltage When two wires composed of dissimilar metals are joined a voltage is generated The voltage is a function of the junction temperature and the types of metals in the thermocouple wire Since the temperature characteristics of many dissimilar metals are well known a conversion from the voltage generated to the temperature of the junction can be made For example a voltage measurement of a T type thermocouple made of copper and constantan wire might look like this Internal DMM Cu Cu J1 TYPE T Cu ra c i Notice however that the connections made between the thermocouple wire and the internal DMM make a second unwanted thermocouple where the constantan C lead connects to the internal DMM s copper Cu input terminal The voltage generated by th
426. ure the four Alarm Output hardware lines e Clear the state of the four alarm output lines e Select the Latch or Track mode for the four alarm output lines e Select the slope rising or falling edge for the four alarm output lines Configure the event or action that controls the scan interval e Select the scan interval mode interval manual external or alarm e Select the scan count 35 Chapter 2 Front Panel Overview Front Panel Menu Reference Configure the advanced measurement features on displayed channel e Set the integration time for measurements on the displayed channel e Set the channel to channel delay for scanning e Enable disable the thermocouple check feature T C measurements only e Select the reference junction source T C measurements only e Set the low frequency limit ac measurements only e Enable disable offset compensation resistance measurements only Select the binary or decimal mode for digital operations digital input output only Configure the totalizer reset mode totalizer only e Select which edge is detected rising or falling for totalizer operations Configure system related instrument parameters e Set the real time system clock and calendar e Query the firmware revisions for the mainframe and installed modules e Select the instrument s power on configuration last or factory reset e Enable disable the internal DMM e Secu
427. urements on the specified channels Use 85 to specify 0 00385 or 91 to specify 0 00391 The default is 85 The TYPE query returns the RTD type in use on the specified channels Returns 85 or 91 SENSe TEMPerature TRANsducer RTD RESistance REFerence lt reference gt lt ch_list gt RTD RESistance REFerence lt ch_list gt FRTD RESistance REFerence lt reference gt lt ch_list gt FRTD RESistance REFerence lt ch_list gt Set the nominal resistance Ro for RTD measurements on the specified channels Select a value between 49 and 2 1 kQ The default is 1002 The REF query returns the nominal resistance Rg in use on the specified channels Returns a number in the form 1 00000000E 02 Thermistor Commands SENSe TEMPerature TRANsducer THERmistor TYPE 2252 5000 10000 lt ch_list gt THERmistor TYPE lt ch_list gt Select the thermistor type for measurements on the specified channels The default is a 5 kQ thermistor The TyPE query returns the thermistor type in use on the specified channels Returns 2252 5000 or 10000 222 Chapter 5 Remote Interface Reference Voltage Configuration Commands Voltage Configuration Commands See also Voltage Measurement Configuration in chapter 4 starting on page 113 INPut IMPedance AUTO OFF ON lt ch_list gt IMPedance AU
428. urns O if no state has been stored or if it has been deleted Returns 1 if a valid state is stored in this location MEMory NSTates Query the total number of memory locations available for state storage Always returns 6 memory location 0 is included 263 Chapter 5 Remote Interface Reference System Related Commands System Related Commands See also System Related Operations in chapter 4 starting on page 140 SYSTem DATE lt yyyy gt lt mm gt lt dd gt Set the instrument calendar The setting is stored in non volatile memory When shipped from the factory instrument is set to the current time and date U S Mountain Time For example the following command sets the calendar to J une 1 1997 SYST DATE 1997 06 01 SYSTem DATE Read the instrument calendar Returns three numbers in the form 1997 06 01 SYySTem TIME lt hh gt lt mm gt lt ss sss gt based on 24 hour clock Set the instrument clock The setting is stored in non volatile memory When shipped from the factory instrument is set to the current time and date U S Mountain Time F or example the following command sets the time to 6 30 PM SYST TIME 18 30 00 SYSTem TIME Query the instrument clock Returns three numbers in the form 18 30 00 FORMat READing TIME TYPE ABSolute RELative READing TIME TYPE Select the time format for storing scanned data in memory You can select abs
429. ut bit is capable of directly driving up to 10 TTL loads less than 1 mA The buffer for each port is used to drive a high output from the internal 5V supply through the diode The drive is rated at 2 4V minimum at 1 mA e Each output bit is also an active sink capable of sinking up to 400 mA from an external power supply The FET is used to sink currents and has a nominal on resistance of 0 2Q e For non TTL logic you must provide an external pull up A description of the pull up calculation is given on the following page e Ifused with an external power supply and pull up the external supply must be greater than 5 Vdc and less than 42 Vdc 393 Chapter 8 Tutorial Multifunction Module Using an External Pull Up In general an external pull up is required only when you want to set the output high value greater than TTL levels For example to use a 12V external power supply the value of the external pull up resistor is calculated as follows Vec 12 Vdc Imax lout low X safety factor 1 mA x 0 5 0 5 mA Vcc 12 os Imax 0 0005 ae The value of the logic high level with the external 24 kQ pull up resistor is calculated as follows R external 12x 24 kQ 8 47 Vdc external R internal 24 ko 10 ko Vhigh Voc X R Driving External Switches You can use two digital output channels to control an external switch For example you can drive the HP 865X series of microwave switch
430. ut it does clear all bits in the event register A STATus PRESet does not clear the bits in the Standard Event enable register To enable bits in the enable register you must write a dedmal value which corresponds to the binary weighted sum of the bits you wish to enable in the register The ESE query returns a decimal value which corresponds to the binary weighted sum of all bits enabled by the ESE command 288 Chapter 5 Remote Interface Reference Status System Commands Alarm Register Commands See the table on page 284 for the register bit definitions STATus ALARm CONDition Query the condition register in this register group note that this condition register uses only bit 4 This is a read only register and bits are not cleared when you read the register A RST Factory Reset clears the Queue Empty bit bit 4 in the condition register A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus ALARm EVENt Query the event register in this register group This is a read only register Once a bit is set it remains set until cleared by the STATus ALARm EVENt command or CLS clear status command A query of this register returns a decimal value which corresponds to the binary weighted sum of all bits set in the register STATus ALARm ENABle lt enable_value gt STATus ALARm ENABle
431. utput channels The actuator switches can also be used to control power devices e When used with high power devices however it is critical that you provide protection to the switch from capacitive and inductive loads to ensure maximum relay life for more information on attenuators see the discussion on page 387 69 Features and Functions Features and Functions You will find that this chapter makes it easy to look up all the details about a particular feature of the HP 34970A Whether you are operating the instrument from the front panel or over the remote interface this chapter will be useful This chapter is divided into the following sections e SCPI Language Conventions on page 73 e Scanning starting on page 74 e Single Channel Monitoring starting on page 93 e Scanning With External Instruments starting on page 95 e General Measurement Configuration starting on page 98 e Temperature Measurement Configuration starting on page 106 e Voltage Measurement Configuration starting on page 113 e Resistance Measurement Configuration on page 115 e Current Measurement Configuration starting on page 116 e Frequency Measurement Configuration starting on page 118 e Mx 4B Scaling starting on page 119 e Alarm Limits starting on page 122 e Digital Input Operations starting on page 133 e Totalizer Operations starting on page 135 e Digital Output Operations on page 138 e DAC Output Operations on page 13
432. value gt STAT ALARm ENABle lt value gt Status Byte Register STAT QUES ENABle STAT ALARm ENABle y 9 Output Buffer c EN oj _ lt i gt 1 lt 2 gt 2 _ lt 4 gt a 3 lt 8 gt OF 4 a4 lt 16 gt i e 5 lt 32 gt 6 7 lt 128 gt Standard Operation Register Serial Poll SRE lt value gt STB SRE C EV EN Summary Bit RQS 0 lt 1 gt 1 lt 2 gt Standard Event Register 2 lt gt 3 lt 8 gt EV EN Scanning 4 lt 16 gt i 5 lt 32 gt Operation Complete 0 lt 1 gt 6 lt 64 gt 1 lt 2 gt 7 lt 128 gt 1 Query Error 2 lt 4 gt Config Change 8 lt 256 gt OR Device Error 3 lt 8 gt j Mem Threshold 9 lt 512 gt Execution Error 4 lt 16 gt u OR 10 Z10245 Command Error 5 lt 32 gt 11 lt 2048 gt 6 lt 64 gt 12 lt 4096 gt Power On 7 lt 128 gt 13 lt 8192 gt 14 lt 16384 gt ESR cS eras T NOT USED STAT OPER COND STAT OPER EVENt STAT OPER ENABle lt value gt STAT OPER ENABle 276 Chapter 5 Remote Interface Reference The SCPI Status System The Status Byte Register The Status Byte register group reports conditions from the other register groups Data in the instrument s output buffer is immediately reported on the Message Available bit bit 4 Clearing an event register from one of the other register groups will dear the corresponding bits in the Status Byte condition register Reading all messages from the output buffer including any pen
433. verifies that the same module types are installed in each slot If a different module type is installed the instrument will perform the equivalent of a Card Reset SYSTem CPON command on that slot e You can assign a name to the storage locations you cannot assign a name to location O You can name a location from the front panel or over the remote interface but you can only recall a named state from the front panel From the remote interface you can only recall a stored state using a number 0 through 5 140 Chapter 4 Features and Functions System Related Operations e The name can contain up to 12 characters The first character must be a letter A Z but the remaining 11 characters can be letters numbers 0 9 or the underscore character _ Blank spaces are not allowed An error is generated if you specify a name with more than 12 characters e A Factory Reset RST command does not affect the configurations stored in memory Once a state is stored it remains until it is overwritten or specifically deleted e Front Panel Operation NAME STA TE STORE STATE RECALL STATE r After recalling a stored state you will notice that a new choice UNDO RECALL is added under RECALL STATE This allows you to cancel the last recall operation and revert to the previous state You can also selet LAST PWR DOWN to recall the state of the instrument at the power down
434. ves six digits of resolution a 0 1 second gate gives five digits and so forth 1st Edge Last Edge ia nnn Gate Count 376 Chapter 8 Tutorial Measurement Fundamentals Sources of Error in Frequency and Period Measurements The internal DMM s ac voltage measurement section performs input signal conditioning All frequency counters are susceptible to errors when measuring low voltage low frequency signals The effects of both internal noise and external noise pickup are critical when measuring slow signals The error is inversely proportional to frequency Measurement errors will also occur if you attempt to measure the frequency or period of an input following a dc offset voltage change You must allow the internal DMM s input dc blocking capacitor to fully settle before making frequency measurements 1 4 Input Error 10 mV 10 Hz 0 5 4 10 mV 100 Hz 100 mV 10 Hz Co T T 1mvV 2 mV 3 mV Input Random Noise RMS If the external noise pickup becomes large enough to exceed the hysteresis of the measuring circuitry the frequency function may actually become unusable External shielding and low pass filtering may help 377 Chapter 8 Tutorial Low Level Signal Multiplexing and Switching Low Level Signal Multiplexing and Switching Low level multiplexers are available in the following types one wire 2 wire and 4 wire The
435. w terminal connections ac current 21 ac voltage 21 de current 21 dc voltage 21 frequency 21 period 21 resistance 21 RTDs 21 thermistors 21 thermocouples 21 wire strain relief 20 wire strip length 20 secure calibration 157 security code calibration factory setting 155 to change 157 self test complete 17 143 failure 17 power on 17 143 sense connections 380 sense connections RTD 110 sensitivity 416 sensor types 56 serial COM ports 273 serial RS 232 interface baud rate 152 cables 17 51 273 connection to computer 272 connector location 5 connector pinout 273 data frame format 272 flow mode 153 selecting interface 151 parity 152 troubleshooting 273 serial poll 278 service request SRQ 278 settling delay automatic 89 default value 88 defined 88 settings 88 settling time 372 settling time ac voltage 361 shearing strain 373 shielding 338 shielding thermocouple wire 353 SHIFT annunciator 4 16 Shift key 16 short form SCPI commands 297 shunt impedance 353 signal conditioning 61 signal conditioning ac voltage 359 dc voltage 354 simplified schematic HP 34901A 164 HP 34902A 166 HP 34903A 168 HP 34904A 170 HP 34905A 172 HP 34906A 172 HP 34907A 174 HP 34908A 176 single channel Monitor 93 94 sink current digital output 393 sliding shelf kit rack mounting 31 slope alarm output lines 129 slot numbering 5 slow ac filter 114 361 slow time
436. when the totalizer actually records counts by providing a gate signal G and G terminals on the module A TTL high signal applied to the G terminal enables counting and a low signal disables counting A TTL low signal applied to the Q terminal enables counting and a high signal disables counting The totalizer only counts when both terminals are enabled You can use either the G terminal the G terminal or both When a gate is not connected the gate terminal floats to the enabled state effectively creating a gate always condition ee oe er a ee ee Gate Signal High True Totalizer Input Le ay Add to Total Totalizer Errors e Noise on the totalizer input can be a problem especially on signals with a slow rise time This noise can create a false indication of a threshold crossing For more information on cabling noise see page 335 e Contact bounce on external switches can create false counts All mechanical switches bounce when they open and close Use an external capacitor to filter the contact bounce 5V Switch Noise cause by bounce Closed creates a false count NNV Limit Switch Totalizer 396 Chapter 8 Tutorial Multifunction Module Voltage DAC Output The HP 34907A module has two analog outputs capable of outputting calibrated voltages between 12 volts with 16 bits of resolution Each DAC Digital to Analog Converter channel can be u
437. y one channel per bank at a time closing one channel in a bank will open the previously closed channel These modules respond only to the CLOSE command OPEN does not apply To open a channel send the CLOSE command to another channel in the same bank 390 Chapter 8 Tutorial RF Signal Multiplexing Sources of Error in RF Switching Impedance mismatching can cause a variety of errors in an RF multiplexing system These errors can cause distorted waveforms overvoltage or undervoltage conditions To minimize RF impedance mismatching e Use the correct cable and connector for the circuit impedance 509 or 759 Note that it is difficult to visually differentiate a 50Q connector from a 75Q connector e Be sure that all leads and signal paths are properly terminated Unterminated sections of line can appear as near shorts at RF frequencies Note that the HP 34905A and HP 34906A do not automatically terminate open channels Insertion Loss 50Q Insertion Loss 75Q OdB OdB 1 dB 1 dB 2 dB 2 dB 3 dB 3 dB 4 dB 4 dB 10 MHz 100 MHz 1 GHz 3GHz 10 MHz 100 MHz 1 GHz 3GHz Direct to Module Siors Using provided adapter cables VSWR 509 VSWR 750 1 60 1 40 1 20 1 00 10 MHz 100 MHz 1 GHz
438. y to the instrument s output buffer but the readings are not stored in reading memory The default DEF transducer type is a 5 kQ thermistor MEASure VOLTage DC MEASure VOLTage AC lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for dc or ac voltage measurements and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directly to the instrument s output buffer but the readings are not stored in reading memory F or ac measurements the resolution is actually fixed at 614 digits the resolution parameter only affects the number of digits shown on the front panel 208 Chapter 5 Remote Interface Reference The MEASure and CONFigure Commands MEASure RESistance MEASure FRESistance lt range gt AUTO MIN MAX DEF lt resolution gt MIN MAX DEF lt scan_list gt Configure the specified channels for 2 wire or 4 wire measurements and immediately sweep through the scan list onetime Note that this command also redefines the scan list The readings are sent directly to the output buffer but the readings are not stored in reading memory For 4 wire measurements FRES the instrument automatically pairs channel n with channel n 10 34901A or n 8 34902A to provide the source and sense connections F or example make the source connections to
439. y to the instrument s output buffer but readings are not stored in memory Note Sending MEASure is functionally the same as sending CONFigure followed immediately by a READ command Using the CONFigure Command For a little more programming flexibility use the CONFigure command When you execute this command the instrument uses the default values for the requested measurement configuration like the MEASure command However the scan is not automatically started and you can change some measurement attributes before initiating the scan This allows you to incrementally change the instrument s configuration from the default conditions The instrument offers a variety of low level commands in the ROUTe SENSe SOURce CALCulate and TRIGger subsystems Note Use the INITiate or READ command to initiate the scan The INITiate command stores the readings in memory Use the FETCh command to retrieve the stored readings from memory 202 Chapter 5 Remote Interface Reference Simplified Programming Overview Using the range and resolution Parameters With the MEASure and CONFigure commands you can select the measurement function range and resolution all in one command Use the range parameter to specify a fixed range larger than the expected value of the input signal You can also set the range parameter to AUTO to select autoranging For frequency and period measurements the instrument uses one ran
440. z VSWR 500 1 80 1 60 10 MHz 100 MHz 1 GHz 3GHz Crosstalk 50Q 20 dB 40 dB 60 dB 80 dB 100 dB 10 MHz 100 MHz 1 GHz 3 GHz OdB 1 dB 2 dB 3 dB 4 dB Insertion Loss 750 10 MHz 100 MHz 1 GHz 3 GHz Direct to Module Using provided adapter cables 1 80 1 60 1 40 1 20 1 00 VSWR 750 10 MHz 100 MHz 1 GHz 3 GHz 20dB 40 dB 60 dB 80 dB 100 dB Crosstalk 75Q 10 MHz 100 MHz 1 GHz 3 GHz 411 Chapter 9 Specifications Module Specifications HM Module Specifications HP 34907A E Software Specifications Digital Input Output HP BenchLink Data Logger not included with Option 001 Port 1 2 Vin L Vin H Vout L Vout H Vout H Max Alarming Speed Latency Read Write Speed 8 Bit input or output non isolated lt 0 8V TTL gt 2 0V TTL lt 0 8V lout 400 mA gt 2 4V lout 1 mA lt 42V with external open drain pull up Maskable pattern match or state change 4 ms max alarm sampling 5 ms typical to 34970A alarm output 95 s Totalize Input Maximum Count Totalize Input Signal Level Threshold Gate Input Count Reset Read Spe

HP 34970A User's Manual

Contents

Download Pdf Manuals

Related Search

Related Contents