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1. Insertion Loss 509 Insertion Loss 75Q 0 dB 0dB a Ty 1 dB S 1 0B nq w 2 dB S 2 dB 3 dB 3 dB 4 dB 4 dB 10 MHz 100 MHz 1GHz 3GHz 10 MHz 100 MHz 1GHz 3GHz Direct to Module cee Using provided adapter cables VSWR 509 VSWR 759 1 80 1 80 1 60 1 60 1 40 1 40 1 20 1 20 1 00 1 00 10 MHz 100 MHz 1 GHz 3 GHz 10 MHz 100 MHz 1 GHz 3 GHz 313 Chapter 7 Tutorial Multifunction Module Multifunction Module Digital Input The 34907A 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 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 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 exa
2. Lo Ol WIRING LOG Slot Number 0100 0200 0300 ee a X 3 Refer to the diagrams on page 27 to connect wiring to the module 7 F Maximum Input Voltage 42 V o Maximum Input Current 700 mA ae Maximum Switching Power 20 W XL 8 a Ng Ten color coded cables are included with the module To order a additional cables use the following cable kit part numbers N aaa 10 cables are included ZX 34905 60001 500 cables MW 34906 60001 759 cables Lo Pe p D gt F i Z 3 ie D 3 A Kp S SMB to BNC Cable Ed 210 26 Bits 16 Chapter 4 Features and Functions 34907A Multifunction Module 34907A Multifunction Module This module combines two 8 bit ports of digital input output a 100 kHz totalizer and two 4 12V analog outputs For greater flexibility you can read digital inputs and the totalizer count during a scan 2 Bit 0 2 _ Port 1 LSB Channel 01 DIO gt Bit 7 2 Bit 0 A Port 2 MSB Channel 02 LS Bit 7 IN A IN TOT gt Channel 03 2 Gate 2 Gate DAC 1 Channel 04 DAC 2 gt Channel 05 16 Digital Input Output The DIO consists of two 8 bit ports with TTL compatible inputs and output The open drain outputs can sink up to 400 mA Fr
3. oop oo m 99 N st ied line fuse O L 1 Slot Identifier 100 200 300 4 Power Line Fuse Holder Assembly 2 Chassis Ground Screw 5 LAN Connector 3 Ext Trig Input Alarm Outputs Channel 6 USB Drive Connector Advance Input Channel Closed Output 7 USB Interface Connector for pinouts see pages 99 and 145 Use the Menu to e Select and configure the LAN and USB interfaces 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 10 BenchLink Data Logger 3 at a Glance The Keysight BenchLink Data Logger 3 software provides a convenient way to collect and analyze your data The software uses a familiar spreadsheet environment streamlining your data gathering needs Simply identify the measurements you want to acquire initiate the process and see the data displayed on the computer screen Use one of the many options to analyze and display your data strip charts histograms with statistical analysis bar and scatter charts individual channel results and more
4. 34970A 34972A External DMM a OES a E duit a SO CY DO HH HAREE Ei VM Complete OUT Ext Trig IN In this configuration 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 For an externally controlled scan you must either remove the internal DMM from the 34970A 34972A or disable it see Internal DMM Disable on page 167 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 34970A 34972A and the external instrument The 34970A 34972A must notify the external instrument when a relay is closed and settled including channel delay The 34970A 34972A outputs a Channel Closed pulse from pin 5 on the rear panel connector see previous page In response the external instrument must notify the 34970A 34972A when it has finished its measurement and is ready to advance to the next channel in the scan list The 34970A 34972A accepts a Channel Advance signal on the External Trigger input line pin 6 112 Chapter 4 Fea
5. WIRING LOG Slot Number 0100 4200 0300 Function Comments Cy A I SEE Ea Ze 7 Co mr z z ES im 12g Y FT Q kE xJ S e eg z F2 I E Ori in lz a O Ey gt Fe a OE m See m CI OE Sri FS ya S ES 4 Or SQ Ls im OQ FS m m P 3 a LI LOS ee 4W Sense Channels are paired to Channel n 8 Refer to the diagrams on page 27 to connect wiring to the module Maximum Input Voltage 300 V CAT 1 Maximum Input Current 50 mA Maximum Switching Power 2 W 20 AWG Typical 6mm 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 devices connected to the module 204 Chapter 4 Features and Functions 34903A 20 Channel Actuator 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 near the screw terminals to implement custom circuitry such as simple filters snubbers and voltage dividers The breadboard area provides the space necessary to ins
6. SIL IW MALONE 02 DIO 2 03 Totalizer Input Input Gate Gate Output GND Output GND Threshold Jumper Position 04 DAC 1 05 DAC 2 OTTL GAC Refer to the diagrams on page 27 to connect wiring to the module Digital Input Output Vin L lt 0 8V TTL Vin H gt 2 0V TTL Vout L lt 0 8V lout 400 mA Vout H gt 2 4V lout 1mA Vin H Max lt 42V with external open drain pull up Totalizer Maximum Count 67 108 863 26 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 20 AWG Typical _ 7 6mm 212 Chapter 4 Features and Functions 34908A 40 Channel Single Ended Multiplexer 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 thermocouple reference junction to minimize errors due to thermal gradients when measuring thermocouples Channel Switches 2H 01 m 2H 20 2 H Com Backplane Switch 2L Com Internal i ov ve Bank Switch DMM Input o lt o npu 98 QH 21 Reference a L o 6 2H 40 Junction JT Sensor NOTES
7. Determining the Status of LAN Connectivity You can determine whether you are connected to the LAN This menu item simply indicates the status it does not allow you to connect If your instrument loses LAN connectivity it may take up to 30 seconds for the LXI FAULT message to appear Front Panel Operation STAT CONNECTED LXI FAULT 188 Chapter 4 Features and Functions Remote Interface Configuration 34972A Resetting the LAN You can reset the instrument s LAN settings to their default values Front Panel Operation RESET LAN NO YES Enabling and Disabling DHCP You can enable or disable Dynamic Host Configuration Protocol DHCP When DHCP is enabled factory setting the instrument will try to obtain an IP address from a DHCP server If a DHCP server is found it will assign a dynamic IP address Subnet Mask and Default Gateway to the instrument If a DHCP server is not found the instrument uses AutolIP to automatically configure its IP setting in the Automatic Private IP Addressing range 169 254 xxx xxx When DHCP is disabled the instrument will use the static IP address Subnet Mask Default Gateway and DNS Server during power on Front Panel Operation DHCP ENABLED DISABLED 189 Chapter 4 Features and Functions Remote Interface Configuration 34972A Setting the IP Address You can set the IP address for your 34972A This menu
8. JU WU gi 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 O00 Cy CG Elie Estey s m l EN I OO OO a SC NS x Co IJL GOO qq ees CIL 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 38 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 an overview of the front panel menus and many front panel operations See chapter 4 Features and Functions starting on page 87 for a complete discussion of the instrument s capabilities and operation This chapter is divided into the following sections Front Panel Menu Reference on page 41 To Monitor a Single Channel on page 44 To Set a Scan Interval on page 45 To Apply Mx B Scaling to Measurements on page 46 To Configure Alarm Limits on page 47 e To Read a Digital Input Port on page 49 To Write to a Digital Output Port on page 50 To Read the Totalizer Count on page 51 To Output a DC Voltage on page 52 To Configure the Remote Interface 34970A on page 58 To Configure the Re
9. Fuse 500 mAT for all line voltages Keysight Part Number 2110 0458 3 Rotate the line voltage selector until the 4 Replace the fuse holder assembly in the correct voltage appears in the window rear panel 100 120 127 220 230 or 240 VAC 35 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 i Bench top viewing position Carrying position 36 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 Keysight System IT instrument of the same size can be rack mounted beside the 34970A 34972A Note Remove the carrying handle and the front and rear rubber bumpers before rack mounting the instrument Sint ME I Aih mnan To remove the handle rotate it to the vertical position and pull the ends outward Front Rear bottom view To remove the rubber bumper stretch a corner and then slide it off 37 Chapter 1 Quick Start To Rack Mount the Instrument To rack mount a single instrument order adapter kit 5063 9240
10. include lt visa h gt include lt stdio h gt include lt string h gt define ADDR 9 Set GPIB 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 GPIB card The address format looks like this GPIBO 9 INSTR strcpy Visa_address GPIBO strcat Visa_address ADDR strcat Visa_address INSTR Open communication session with the 34970A viOpenDefaultRM amp defaultRM viOpen defaultRM 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 Ss 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 251 Chapter 6 Application Programs Example Programs for C and C l C C Example stat_reg c stat_reg c BKK IK KK IK I KR I RR IRR IR AR RR RA RRR AAA IAA AA IA A IA I
11. lt ch_list gt Select EQUal 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 ignored To enable the specified alarm mode send the following command CALCulate COMPare STATe ON lt ch_list gt 149 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 gene
12. Digital Output Operations The multifunction module 84907A has two non isolated 8 bit input output ports which you can use for outputting digital patterns The digital output channels are numbered s01 lower byte and s02 upper byte where s represents the slot number You cannot configure a port for output operations if that port is already configured to be part of the scan list digital input From the front panel you can write to one 8 bit output port at a time From the remote interface you can write to both ports simultaneously 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 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 A amp 3 from the front panel resets only the port currently selected both ports are not reset 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 Advarced USE DECIMAL USE BINA
13. External DMM 5 i o IN gt 00o0ocooo S giziziz isinisi M ogo Common Terminals COM 79 Chapter 3 System Overview Measurement Input To control scanning with an external instrument two control lines are provided When the 34970A 34972A and the external instrument are properly configured you can synchronize a scan sequence between the two GND 5 1 Channel Closed OUT lt o Q og Ext Trig IN e 34970A 34972A External DMM Oj ya aN U a gi g gt o oe oe m C p4 J TAA Coo Ten TAO e HAAA VM Complete OUT Ext Trig IN 80 Chapter 3 System Overview Measurement Input The Multifunction Module The multifunction module 84907A 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 re
14. 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 indext1 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 statusByte Read status 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 253 254 Tutorial Tutorial T
15. 71 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 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 7 Z Source 1 Z Pea ZA PN y LA K ae P S a F Z o Source 2 fof J We L gt A ON 7 AV Wa S ras ie La Ss Source 3 3 a a ae a 4 ys je A Ay 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 72 NO Normally Open NC Normally Closed Chapter 3 System Overview Signal Routing and Switching Form C SPDT Switching The 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 A NO gt A NO m e A NC ANC 3 COM 2 COM 73 Chapter 3 System Overview Measurement Input Measurement Input The 3497
16. Channel Open Channel Closed NC Contact Connected NO Contact Connected o NO A NO s NC gt 2 NC 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 Current 85 Chapter 3 System Overview Control Output For control applications the actuator has the following advantages Higher voltage and power rating than the digital output channels The actuator switches can also be used to control power devices 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 309 86 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 34970A 34972A 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 SCPI Language Conventions on page 89 Scanning on page 90 Scanning with External Instruments on page 111 General Measurement Configuration on page 115 Temperature Measurement Conf
17. EMory IMPort CONFiguration lt configuration_file gt EMory IMPort CATalog For more information on the SCPI commands available to program the instrument over the remote interface see the MMEMory commands in the Keysight 34970A 84972A Programmer s Reference Help Folder and File Structure Folder Description Each saved scan will be stored in a top level folder named 34972A data instrument SN yyyymmdd_hhmmssmmm The square brackets are not actually part of the directory name and the yyyymmdd_hhmmssmmm is a timestamp indicating the approximate start of the scan The format is year yyyy month mm day dd underscore _ hours hh minutes mm seconds ss and milliseconds mmm 177 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A For example the folder named 34972A data MY00012345 20091210 134523123 would indicate a scan on instrument number MY00012345 that started approximately 23 123 seconds after 1 45 pm 13 45 on December 10 2009 File Descriptions The top level folder described above will contain two types of files The first is a file named as follows config csv This is a text file that documents the instrument configuration for this scan The timestamp is as described above This file lists the configuration of the instrument in a human readable form In addition to the config csv file you will have one or more data files na
18. 334 Wi Typical AC Performance Graphs 34905A 34906A Insertion Loss 509 0 dB 1 dB 2 dB 3 dB 4 dB 10 MHz 100 MHz VSWR 50 1 GHz 1 80 1 60 1 40 1 20 1 00 10 MHz 100 MHz Crosstalk 509 1 GHz 3 GHz 20dB 40 dB 60 dB 80 dB 100 dB 10 MHz 100 MHz 1 GHz 3 GHz 0 dB 1 dB ii 2 dB 3 dB 4 dB Chapter 8 Specifications Typical AC Performance Graphs Insertion Loss 759 10 MHz 100 MHz 1 GHz Direct to Module Using provided adap 1 80 1 60 1 40 1 20 1 00 er cables VSWR 75 3 GHz 10 MHz 100 MHz 1 GHz 20dB 40 dB 60 dB 80 dB 100 dB Crosstalk 75Q 3 GHz 10 MHz 100 MHz 1 GHz 3 GHz 335 Chapter 8 Specifications Module Specifications Wi Module Specifications 34907A Digital Input Output Port 1 2 8 Bit input or outp
19. 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 Bit 0 8 Port 1 LSB g Channel 01 Digital ene Output 2 Bit 0 8 _ Port 2 MSB G Channel 02 1 Bit 7 83 Chapter 3 System Overview Control Output Voltage DAC Output The multifunction 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 used as a programmable voltage source for analog input control of other devices A simplified diagram is shown below 2 Channel 04 16 DAC 2 2 Channel 05 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 supplying 10 mA maximum current Note You must limit the output current to 40 mA total for all three slots six DAC channels 84 NO Normally Open NC Normally Closed Chapter 3 System Overview Control Output The Actuator General Purpose Switch You can think of the 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
20. System Related Operations Display State Error Queue Stored States Instrument Preset State No Change No Change No Change No Change Count Not Reset When Read Rising Edge Instrument Preset State No Change All Readings are Cleared No Change No Change No Change No Change No Change Stopped Instrument Preset State No Change No Change No Change Instrument Preset State No Change No Change No Change No Change Output Lines are Cleared No Change Instrument Preset State All Channels Open All Channels Open Channels s11 and s21 Selected Both DIO Ports Input Totalizer Count 0 Both DACs 0 VDC Instrument Preset State No Change Errors Not Cleared No Change 198 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 Resistance AC Low Frequency Filter Channel Delay Resistance Measurements Range Resolution Integration Time Offset Compensation Channel Delay Frequency P
21. Refer to the diagrams on page 27 to connect wiring to the module Only one channel can be closed at a time closing one channel will open the previously closed channel This module cannot be used to directly measure current or any 4 wire measurements When connecting thermocouples to the screw terminals on this module not recommended due to the common LO configuration be sure to provide electrical isolation between thermocouples to avoid current loops and subsequent measurement errors Connections to AC line are not recommended unless you provide external transient Maximum Input Voltage 300 V CAT I 20 AWG Typical Maximum Input Current 1 A Maximum Switching Power 50 W 6mm A 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 213 Chapter 4 Features and Functions 34908A 40 Channel Single Ended Multiplexer WIRING LOG Slot Number Function 0100 0200 0300 Comments Ea L3 b He gt a z i E
22. Celsius F Fahrenheit or K Kelvin You can mix temperature units on different channels within the instrument and on the same module The instrument 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 Setting the Mx B measurement label to C F or K has no effect on the temperature measurement units currently selected Front Panel Operation First select the temperature function on the active channel Then select the temperature units UNITS F Remote Interface Operation UNIT TEMP F 103 123 Chapter 4 Features and Functions Temperature Measurement Configuration Thermocouple Measurements To connect a thermocouple to the module s screw terminals see page 28 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 Ifyou 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
23. M 136 138 default offset B 136 138 equation used 136 interaction with alarms 136 null stored as offset 136 setting gain M 46 138 setting offset B 46 138 strain measurements 295 valid gain M values 137 valid offset B values 137 while scanning 91 136 SCAN annunciator 8 scan configuration copying 32 scan configuration front panel 30 scan count continuous 45 102 default value 45 102 settings 45 102 scan interval default value 45 97 resolution 97 setting from front panel 97 setting from remote 97 Scan key 31 94 scan list adding channels to 94 building from front panel 94 building from remote 95 defining 30 31 examples 89 reading digital input 49 reading totalizer count 51 rules 89 scan sweep defined 96 scanning aborting a scan 94 95 alarm mode 100 channel delay 105 clearing memory 91 94 95 external mode 99 external scan with digital in put 113 initiating from front panel 94 initiating from remote 95 interval timer mode 97 interval trigger 96 manual once mode 98 memory overview 91 modules allowed 90 on alarm 100 power failure 93 reading format 104 readings stored in memory 91 removing modules during 92 rules 90 scan once manual mode 98 statistics 91 stopping scan 97 storing readings 92 timer interval mode 97 viewing readings 107 with alarms 92 with digital input channels 92 353 Index w
24. Option Explicit Sub takeReadings Columns 1 ClearContents Columns 2 ClearContents Dim I As Integer Used for counter in For Next loop Dim numberMeasurements As Integer Number of readings Dim measurementDelay As Single Delay between relay closure and measurement Dim points As Integer r POUT Ur YY Te Pr OY YOY WYO We OY YOY OY Oe WY VY OY VY Oe ey OY vy ve OY VY vee Oe ny Oe ve oe Pony Oe Oe Oe Oe OY OY OY Oe OY OY nv vee vo ny oo To change the GPIB address modify the variable VISAaddr below VISAaddr 9 OpenPort Open communications on GPIB SendSCPI RST Issue a Factory Reset to the instrument POTEET TUT YT OY PT eT We OY Te OY VT WYO We OY OY OT OY OY WY VY OY VY Oe OY OY YOY VY Oe OY Oo OY Oe ve Oe Ov Oe Ov Oe ve OY OY ve ev OY Ov Ov evan oa r SET UP Modify this section to select the number of readings channel delay and channel number to be measured r numberMeasurements 10 Number of readings measurementDelay 0 1 Delay in secs between relay closure and measurement Configure the function range and channel SendSCPI CONF VOLT DC 103 Configure channel 103 for DC voltage OTT UT AY TOY PT EP OY TOYO WYP WOO OY VY WY VOY VOY UY NYY OY VY OY OY OY OY OY Oe PY Oe OOO OY POV WYO WYO OY WYO WY OY OY OY vv vO Yn no Select channel delay and number of readings SendSCPI ROUT CHAN DELAY amp Str measurementDelay SendSCPI TRIG COUNT amp StrS numberMeasureme
25. 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 235 701 702 703 704 705 706 707 708 709 Chapter 5 Error Messages Calibration Errors Calibration Errors The following errors indicate failures that may occur during a calibration Refer to the 34970A 84972A Service Guide for more information 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 Cal secured The instrument is secured against calibration Cal invalid secure code You have entered an invalid calibration security 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 HP084970 or AT034972 when the instrument is shipped from the factory Cal secure code too long The security code may contain up to 12 alphanumeric
26. TYPE T Cu ye A S TYPE T 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 if Cu ot F 1 Fe P c y oy 2 Fe 7 he 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 not at the same temperature an error will be created in the measurement 270 Chapter 7 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 pan oe Measurement y Gy Thermocouple Cu x Cu IZ Ice Bath ON OOK Ss 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
27. 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 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 245 Chapter 6 Application Programs Example Programs for Excel 7 0 Sub OpenPort POET TUT YT YT eV We OY YOY TOYO We OY OY OY OY WY VY OY VY Oe OY OY OY OY VY Oe OO Oe OY Oe oe ony Oe ve We We OY vv evn Be sure that the GPIB address has been set in the VISAaddr variable before calling this routine FOC TTT 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 UT UY TE UY UT WU Ue TUT TY UY ONY Ue OY Vy O
28. 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 272 To DMM 1 A i Channel 1 L 27 ee i x gt oy ZH channel 2 gt gt Channe DH L Channel 3 Dp i Channel 4 SS Note Only one channel can be closed at a time closing one channel will open the previously closed channel Two Wire Multiplexers The 34901A and 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 272 Channel 1 HY O To DMM L Sd Channel 2 Channel 3 Channel 4 Pro ace re dE Re EE 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 301 Chapter 7 Tutorial Low Level Signal Multiplexing and Switching Four Wire Multiplexers You can make 4 wire ohms measurements using the 34901A and 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 automa
29. default 127 values 127 analog to digital conversion explanation 76 integrating technique 76 non integrating technique 76 annunciators 8 141 aperture time definition 120 selecting 120 application programs C and C 248 Excel 7 0 241 242 attenuation 256 264 307 automatic channel delays 106 Automatic Logging 180 automatic recall power down 57 93 autorange threshold values 115 autozero definition 122 vs integration time 122 average responding error 280 average during scan 91 AWG wire gauge size 256 B backplane relays 200 202 303 bandwidth ac ac current 133 ac voltage 131 vs channel delays 106 bank switch 200 202 212 303 baud rate RS 232 factory setting 54 56 184 selecting 54 56 184 BenchLink Data Logger Software installation 25 on line help 26 software overview 11 bias current dc loading errors 278 binary format digital read 49 151 bits vs integration time 120 block diagram 34970A 64 internal DMM 74 BNC cable kits 34905A 209 34906A 209 braces syntax 89 brackets syntax 89 break before make switching 298 bridge strain gage 295 buffering triggers 99 bumpers removing 37 burden voltage 288 C C and C example programs 248 cable kits SMB to BNC 34905A 209 346 Index 34906A 209 cabling attenuation 256 capacitance 256 coaxial 67 dielectric withstand voltage 255 errors 259 flat ribbon 67 nomi
30. mainframe and plug in modules If you have questions relating to the operation of the 84970A 34972A call 1 800 452 4844 in the United States or contact your nearest Keysight Technologies Sales Office If your 84970A 349724A fails within one year of original purchase Keysight will replace it free of charge Call 1 800 829 4444 and select Option 3 followed by Option 1 15 16 Contents Chapter 1 Quick Start To Prepare the Instrument for Use 238 BenchLink Data Logger Software 25 To Connect Wiring toa Module 27 To Set the Time and Date 29 To Configure a Channel for Scanning 30 To Copy a Channel Configuration 32 To Close a Channel 33 If the Instrument Does Not Turn On 34 To Adjust the Carrying Handle 36 To Rack Mount the Instrument 37 Chapter 2 Front Panel Overview Front Panel Menu Reference 41 To Monitor a Single Channel 44 To Set a Scan Interval 45 To Apply Mx B Scaling to Measurements 46 To Configure Alarm Limits 47 To Read a Digital Input Port 49 To Write to a Digital Output Port 50 To Read the Totalizer Count 51 To Output aDC Voltage 52 To Configure the Remote Interface 34970A 53 To Configure the Remote Interface 34972A 55 To Store the Instrument State 57 U9 U09 Chapter 3 System Overview Data Acquisition System Overview 60 Signal Routing and Switching 70 Measurement Input 74 Control Output 83 17 m c je O Contents C
31. 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 TOTalize 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 it will not resume scanning when the reboot completes If you are logging to a USB drive the instrument will not log any scans that occur between the removal of the module and the reboot of the instrument 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 34970A 34972A 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 remo
32. sent to the display 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 165 Chapter 4 Features and Functions System Related Operations 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 Real Time System Clock During a scan 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 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 166 Chapter 4 Features and Functions System Related Operations Internal DMM Disable You can scan through the configured channels using either the internal DMM or an external instrument For externally controlled scans you must either remove the internal DMM fro
33. 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 neck Cu Fe so Measurement v Thermocouple Cu 2 Cu Aan Ee 5 z Ice Bath External Reference Junction This circuit is the best solution for accurate thermocouple connections 271 Chapter 7 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 reference 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 a Reference Temperature SEA Sensor Cu Cu Fe adl __ Measurement OV Thermocouple 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 ther
34. 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 gives six digits of resolution a 0 1 second gate gives five digits and so forth 1st Edge Last Edge Input Gate Count 298 Chapter 7 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 S Ww Z 10 mv 10Hz k 0 5 ee 10 mv 100 Hz 400 mV 10 Hz T T r 1mV 2 mv 3 mv Input
35. 124 flange kit rack mounting 38 flow mode RS 232 DTR DSR mode 185 factory setting 54 185 Modem mode 186 None no flow mode 185 RTS CTS mode 185 selecting 54 185 XON XOFF mode 185 form C SPDT switching 73 304 format alarm queue data 144 scanned readings 104 four wire multiplexers 71 300 four wire ohms 132 289 four wiring paring RTD 127 frequency measurements connections 28 low frequency timeout 135 sources of error 297 front panel annunciators 8 defining scan list 30 layout 6 menu overview 7 39 front panel display enable disable 165 text message 165 fuse factory setting 34 location 9 10 35 part number 34 replacing 35 fuseholder assembly 9 10 35 G gage factor strain 294 gain M Mx B scaling 46 136 gate signal totalizer 153 316 gauge wire size 256 GET Group Execute Trigger 98 GPIB IEEE 488 address selection 9 53 55 183 cable 61 connector 9 factory address setting 174 180 182 187 interface selection 53 55 183 setting address 174 180 182 187 ground loops 257 261 grounding 257 H handle adjusting 36 removing 37 handshake RS 232 DTR DSR mode 185 factory setting 54 185 Modem mode 186 None no flow mode 185 RTS CTS mode 185 selecting 54 185 XON XOFF mode 185 hardware output lines alarms 145 hardware rack mounting 38 high frequency switching 310 I ice bath 268 TEEE 488 GPIB
36. 209 34906A module 75W channel numbering 208 description 208 310 module overview 13 208 screw terminal diagram 209 simplified schematic 208 wiring log 209 34907A module 8 bit vs 16 bit operations 151 157 ac vs TTL threshold 154 adding to scan list 151 155 binary format 49 151 channel numbering 210 clearing the count totalizer 156 limitations 159 317 decimal format 49 151 description 210 driving microwave switches 314 gate signal 153 maximum totalizer count 154 module overview 14 210 screw terminal diagram 211 simplified block diagrams 210 Totalize Threshold 154 211 totalizer reset mode 155 using alarms 148 wiring log 211 34908A module DAC current jumper channel numbering 212 description 212 module overview 14 212 screw terminal diagram 213 simplified schematic 212 wiring log 213 34970A block diagram 64 firmware revision 167 4W annunciator 8 50W RF switching 310 75W RF switching 310 A ABORT command 95 aborting a scan 94 95 absolute time 104 ac bandwidth ac current 133 ac voltage 131 vs channel delays 106 ac current ac filter 133 281 connections 28 low frequency filter 133 281 measurement ranges 28 133 settling time 133 281 ac filter definition 131 133 281 vs channel delays 106 ac measurement errors 261 ac settling time 131 133 ac voltage measurements ac filter 131 281 connections 28 loading errors 284 low
37. 349 Index address selection 53 55 183 cable 61 connector 9 factory address setting 182 187 188 190 interface selection 53 55 183 setting address 182 187 188 190 impedance mismatching 311 INITiate command description 95 injected current dc voltage 276 input resistance dc loading errors 277 de voltage 130 131 277 INPut IMP AUTO command 131 insertion loss 311 installing BenchLink Data Logger soft ware 25 Instrument configuration import ing 181 instrument preset state 197 instrument state storage definition 57 front panel operation 161 naming states 57 160 power down recall 160 remote operation 161 integral error DAC 318 integrating ADC 76 integration time definition 120 selecting 120 vs channel delays 106 vs number of bits 120 vs number of digits 120 vs resolution 120 Interface key 48 53 55 188 interface GPIB IEEE 488 address selection 53 55 183 cable 61 connector 9 factory address setting 182 interface selection 53 55 183 setting address 182 interface RS 232 serial baud rate 54 cable 61 flow control 54 parity 54 stop bits 54 internal DMM block diagram 263 enabling disabling 167 reading relay count 169 internal reference thermocouple 124 internal timer scan interval 124 Interval key 42 97 113 interval scan default value 97 resolution 97 setting from front panel 97 setting from remote 97 settings 97 inte
38. 400 C 1 0 C 200 C to 100 C 16 C 0 03 C RTD Ro from 49Q 200 C to 600 C 0 06 C 0 003 C to 2 1 kQ 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 6 digits slow AC filter 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 4Q additional error in 2 wire ohms function 5 1 year accuracy For total measurement accuracy add temperature probe error 6 Thermocouple specifications are not guaranteed when 34907A module is present 326 mw DC Measurement and Operating Characteristics Chapter 8 Specifications DC Measurement and Operating Characteristics DC Measurement Characteristics l DC Voltage Measurement Method A D Linearity Input Resistance 100 mV 1V 10 V ranges 100 V 300 V ranges Input Bias Current Input Protection Continuously Integrating Multi slope III A D Converter 0 0002 of reading 0 0001 of range Selectable 10 MQ or gt 10 GQ 10 MQ 41 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 1kQ 10kQ ranges 10 of range per lead for 100 Q
39. A sample of the BenchLink Data Logger 3 features include Tab based user interface simple menu structure A data manager that manages all configurations and data logs simplifies opening renaming deleting and editing easy access to data export A data log name template Automatic data export with preconfigured preferences control of the decimal character and field separator control of the export contents Graph configurations saved and restored automatically the next time Data Logger 3 is opened Graph preferences to allow easy control of graph look and feel Split graphs for easy viewing of independent measurements Import Data Logger I and Data Logger II configurations Configure up to four 34970A 34972As for simultaneous scanning Note To install the software refer to Installing BenchLink Date Logger 3 Software on page 25 To learn more about the software and its capabilities refer to the On Line Help System for BenchLink Data Logger 3 For increased capabilities purchase the optional Keysight BenchLink Data Logger Pro software This software provides advanced data logging and decision making with no programming required 11 The Plug In Modules at a Glance For complete specifications on each plug in modules refer to the module sections in chapter 8 34901A 20 Channel Armature Multiplexer 20 channels of 300 V switching Two channels for DC or AC current measurements 100
40. 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 X0 01 7 set x1 i MQ WN MA T C 1 aoee Xx A x10 A X100 lt The first stage implements a high input impedance 1 MQ switchable 7 compensated attenuator The second stage provides variable gain signal amplification to scale the input to the AC converter to the 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 281 Chapter 7 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 ave
41. 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 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 ALARM 1 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 47 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 al
42. Conditioning G2 Gate Input Ge E GND TTL AC Threshold Jumper You can configure the totalizer to count on the rising edge or falling edge of the input signal 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 W The maximum count is 67 108 863 27 1 The count rolls over to 0 after reaching the maximum allowed value 317 Chapter 7 Tutorial Multifunction Module 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 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 Input Signal 4 Rising Edge Gate Signal High True Totalizer Input Add to Total Tota
43. Gear 99 Chapter 4 Features and Functions Scanning 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 Scanning on Alarm In 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 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 139 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 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 102 for more information All readings
44. Keysight 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 that there is a battery in the instrument A battery must be present for the instrument to boot up 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 280 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 Keysight part number 2110 0458 34 Chapter 1 Quick Start If the Instrument Does Not Turn On 1 Remove the power cord Remove the fuse holder assembly from the rear panel 2 Remove the line voltage selector from the assembly
45. 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 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 20Hz to 300 kHz Medium 1 second reading 0 2 seconds 200 Hz to 300 kHz Fast 0 12 seconds reading 0 02 seconds The instrument 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 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 8 Hz medium filter 20 Hz or fast filter 200 Hz for the active channel The default is the medium filter adored TF 3 HZ SLOW Remote Interface Operation Specif
46. OUY Yy n P4 Ji lt e OSes 261 Chapter 7 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 thermoelectric voltages for connections between dissimilar metals Copper to Approx uV 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 Tim 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 als
47. 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 299 Chapter 7 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 following sections in this chapter describe each type of multiplexer The following low level multiplexer modules are available with the 34970A 34901A 20 Channel Armature Multiplexer 34902A 16 Channel Reed Multiplexer 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 34970A 34972A include the following 34903A 20 Channel Actuator 34904A 4x8 Two Wire Matrix 300 Chapter 7 Tutorial Low Level Signal Multiplexing and Switching One Wire Single Ended Multiplexers On the 34908A multiplexer
48. The earth referenced section communicates with the floating section to provide PC connectivity The 34970A is shipped with both an GPIB IEEE 488 interface and an RS 232 interface Only one interface can be enabled at a time The 34972A is shipped with Local Area Network LAN and Universal Serial Bus USB connectivity 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 64 Chapter 3 System Overview Data Acquisition System Overview 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 Plug In Modules The 34970A 34972A 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
49. 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 HL H L 2 2 2 2 2 gt Row 1 Row2 l l Row 3 AL Row 4 aH EN D 5 Channel 32 ae L Row 3 Column 2 NOTES You can close multiple channels at the same time on this module 207 Chapter 4 Features and Functions 34904A 4x8 Matrix Switch WIRING LOG Slot Number 0100 0200 0300 fz baat m E YJE A S E re m Sita Q Io u 3 gt fed HE Q r g 6 zs g S Z g rg x m JIT g a S A I E re 5 m Ti x 5 Ho m 3 3 4 x Bs rz zJ r z yal Lg LRE ee Comments INI DM on A WIN Example Channel 32 represents Row 3 and Column 2 Refer to the diagrams on page 27 to connect wiring to the module Maximum
50. alarm output lines 146 slot numbering 9 10 slow ac filter 131 281 slow timeout 135 SMB cable kits 209 snubber circuitry 305 software BenchLink Data Logger installation 25 on line help 26 overview 11 source connections RTD 127 source connections 300 SPDT Form C switching 73 304 Standby Power switch 23 state storage definition 57 front panel operation 161 naming states 57 160 power down recall 160 remote operation 161 statistics while scanning 91 Status of LAN Connectivity 187 status register example program 250 Step key 31 94 Sto Rcl key 43 57 stopping scan 97 stored states definition 57 front panel operation 161 naming states 57 160 power down recall 160 remote operation 161 strain gage common uses 294 gage factor 294 measurements 137 293 Mx B equations 137 poisson strain 293 rosette 294 shearing strain 293 Wheatstone bridge 295 strain relief 27 255 stress strain gage 293 strip length wiring 27 Subnet Mask 189 sweep scan defined 94 96 354 Index switch contact resistance 319 switch life 319 switch types form C SPDT 73 matrix 72 multiplexer 71 298 switching errors 301 syntax SCPI conventions 89 system cabling 67 255 system clock factory setting 166 setting the 29 166 SYSTem ERRor command 216 SYSTem PRESet command 197 T technical support phone numbers 3 Web site 3 temperature coefficient 286 temperatur
51. and 1 KQ ranges 1 KQ on all other ranges 300 V on all ranges DC Current Shunt Resistance Input Protection 5 Q for 10 mA 100 mA 0 1 Q for 1A 1 5A 250 V fuse on 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 RTD a 0 00385 DIN IEC 751 using ITS 90 software compensation or a 0 00391 using IPTS 68 software compensation Thermistor 44004 44007 44006 series Measurement Noise Rejection 60 Hz 50 Hz 2 DC CMRR Integration Time 200 PLC 3 33s 4s 100 PLC 1 67s 2s 140 dB Normal Mode Rejection 110 aB 105 dBi 20 PLC 333 ms 400 ms 100 aB 10 PLC 167 ms 200 ms 95 aB 2 PLC 33 3 ms 40 ms 90 dB 1 PLC 16 7 ms 20 ms 60 dB lt 1PLC 0 dB 327 Chapter 8 Specifications AC Accuracy Specifications wi AC Accuracy Specifications of reading of range l Includes measurement error switching error and transducer conversion error i3 Temperature Function Range Frequency 24 Hour 90 Day 1 Year Coefficient C 23 C41 C 23 C 5 C 23 C 5C 0C 18 C 28 C 55 C True RMS 100 0000 mV 3Hz 5Hz 1 00 0 03 1 00 0 04 1 00 0 04 0 100 0 004 AC Voltage 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
52. and 4x16 with up to 96 crosspoints in a single mainframe 34905 6A Dual 4 Channel RF Multiplexers 34905A 50Q 34906A 75Q 2 GHz bandwidth with on board SMB connections 1 GHz bandwidth with SMB to BNC adapter cables provided For detailed information and a module diagram see page 209 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 13 laa aaah 34907A Multifunction Module Two 8 bit Digital Input Output ports 400 mA sink 42 V open collector e 100 kHz Totalize input with 1 Vpp sensitivity Two 16 bit 12 V Calibrated Analog Outputs For detailed information and module block diagrams see page 211 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 34908A 40 Channel Single Ended Multiplexer 40 channels of 300 V single ended common LO switching Built in thermocouple reference junction Switching speed of up to 60 channels per second Connects to the internal multimeter For detailed information and a mod
53. characters A security code was received which contained more than 12 characters Cal aborted A calibration in progress is aborted when you turn off the instrument or send a bus Device Clear Cal value out of range The specified calibration value CALibration VALue is not valid for the present measurement function and range Cal signal measurement out of range The specified calibration value CALibration VALue does not match the signal applied to the instrument Cal signal frequency out of range The input signal frequency for an ac calibration does not match the required input frequency for this calibration Cal no cal for this function or range You cannot perform calibrations for most ac current ranges the 100 MQ resistance range and period 236 710 720 721 722 723 724 725 730 731 732 733 734 735 736 740 741 742 743 744 745 746 Chapter 5 Error Messages Calibration Errors NOTE The following error messages indicate possible hardware failures within the instrument If any of the following errors occur contact your nearest Keysight Service Center for repair Cal full scale correction out of range Cal DCV offset out of range Cal DCI offset out of range Cal RES offset out of range Cal FRES offset out of range Cal extended resistance self cal failed Cal 300V DC correction out of range Cal precharge DAC convergence failed Cal A D turnover correction out of range Cal AC
54. data will not be saved to the USB drive USB operation aborted Cannot save configuration data An abort or device clear was received while fetching configuration data from secondary processor Configuration data will not be saved to the USB drive One or more blefg file names invalid files inaccessible Keysight BenchLink Data Logger BLCFG configuration files on the USB drive are limited to 40 character filenames including the blefg extension and all characters must be ANSI Only legal filenames will be selectable for import Disk contains too many blefg files oldest files inaccessible Instrument will only catalog the 50 most recently created Keysight BenchLink Data Logger BLCFG files Older files will not be selectable for import 233 501 502 511 512 513 514 34970A only 514 34972A only 521 522 532 540 550 Chapter 5 Error Messages Instrument Errors I O processor isolator framing error I O processor isolator overrun error Communications RS 232 framing error Communications RS 232 overrun error 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 Not allowed Instrument locked by another I O session The requested operation is not allowed because another I O session has locked the instrument Communications input buffer overflow Communicatio
55. file on the USB drive Mass storage error failed to create directory The instrument was unable to create the directory on the USB drive Mass storage error failed to remove directory The instrument was unable to remove the directory on the USB drive Not enough disk space The external USB drive is full No external disk detected The operation requires a USB drive which is not detected External disk has been detached The external USB drive has been unplugged File already exists The instrument was unable to create new file because a file with that name already exists on the USB drive 229 414 415 416 417 418 Chapter 5 Error Messages Instrument Errors Directory already exists The instrument was unable to create new directory because a directory with that name already exists on the USB drive File not found The file does not exist on the USB drive Path not found The directory does not exist on the USB drive File not opened for writing The instrument failed to open the file for writing on the USB drive File not opened for reading The instrument failed to open the file for reading from the USB drive 230 450 451 452 453 454 455 457 458 Chapter 5 Error Messages Instrument Errors Overrun during data collection readings lost in USB transfer Internal error readings were collected too fast and were not buffered for output to the USB drive Overrun during USB
56. following command adds a 2 second channel delay to channel 101 ROUT CHAN DELAY 2 101 105 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 PLC lt 1 2 0 ms 1 0 ms Resistance RTD Thermistor 2 and 4 wire Range Channel Delay Range Channel Delay For PLC gt 1 For PLC lt 1 100Q 2 0 ms 100Q 1 0 ms 1 kQ 2 0 ms 1kQ 1 0 ms 10 kQ 2 0 ms 10 kQ 1 0 ms 100 kQ 25 ms 100 kQ 20 ms 1 MQ 30 ms 1 MQ 25 ms 10 MQ 200 ms 10 MQ 200 ms 100MQ 200 ms 100MQ 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 106 Chapter 4 Features and Functions Scanning Front Panel Operation saonces CH DELAY AUTO Remote Interface Operation The following command enables an automatic channel delay on channel 01 ROUT CHAN DELAY AUTO ON 101 Selecting a specifi
57. frequency filter 131 281 ranges 28 130 settling time 131 281 signal conditioning 279 true RMS measurements 280 345 Index actuator switching 73 304 address GPIB factory setting 182 187 188 190 selecting 7 182 187 188 190 address channel number 30 ADRS annunciator 8 Advanced key 42 121 ALARM annunciator 141 ALARM annunciator 8 alarm data viewing 143 Alarm key 41 47 142 alarm limits annunciators 141 clearing alarm outputs 146 configuring 47 default settings 48 142 interaction with Mx B 47 140 output connector location 9 10 output connector pinout 145 output latch mode 145 output slope polarity 146 output track mode 146 scan on alarm 100 setting limits 47 with readings 104 Alarm Out key 41 146 alarm output lines clearing 146 connector location 9 10 connector pinout 145 latch mode 145 slope polarity 146 track mode 146 alarm queue 48 clearing 143 number of alarms 139 output format 144 storing alarms 139 143 alarms alarm output lines 145 annunciators 141 default limit values 142 description 139 front panel annunciators 141 hardware output lines 141 145 interaction with Mx B 140 output connector 145 setting limits 143 storing in alarm queue 139 storing in reading memory 139 viewing alarm queue 143 viewing reading memory 143 while scanning 92 with multifunction module 148 Alarms connector 145 alpha a for RTDs
58. instrument for making voltage measurements The instrument can measure DC and true RMS ac coupled voltages on the measurement ranges shown below 100 mV 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 GQ for the 100 mVDC 1 VDC and 10 VDC ranges Applies to DC voltage measurements only Input Resistance Input Resistance Input Resistance Setting 100 mV 1V 10 V ranges 100 V 300 V ranges Input R Auto OFF 10 MQ 10 MQ Input R Auto ON gt 10 GO 10 MQ The instrument 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 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 GQ The default is 10 MQ INPUT R gt 10 G 130 Chapter 4 Features and Functions Voltage Measurement Configuration Remote Interface Operation You can enable or disable the automatic input resistance mode on the specified channels With AUTO
59. is cycled The instrument stores the state of all modules including all channel configurations scanning setups alarm values and scaling values When shipped from the factory storage locations 1 through 5 are empty location 0 has the power on state 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 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 160 Chapter 4 Features and Functions System Related Operations You can assign a name to the storage locations you cannot assign a name to location 0 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 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
60. it easy to use the instrument with your PC for gathering and analyzing measurements Use this software to set up your test acquire and archive measurement data and perform real time display and analysis of your measurements The Keysight BenchLink Data Logger Pro option available at additional cost provides advanced data logging and decision making with no programming required Automated Testing with Multiple Instruments Keysight VEE TransEra HTBASIC for Windows e National Instruments LabVIEW Microsoft Visual Basic or Visual C 63 Chapter 3 System Overview Data Acquisition System Overview The 34970A 34972A Data Acquisition Switch Unit As shown below the logic circuitry for the 34970A 34972A 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 268 External Trigger j out T IN i Internal Alarms Control 7 Floating l DMM Earth Logic m a a N A an eee I a pee ef bey E To Computer lt can K Digital Analog Bus USB s Bus 34972A RL _ 100 AC Power gt o Pluacl IS F Ta 5 ug i 200 Slots A Optical Isolators 7 300 The earth referenced and floating circuitry communicate with each other via an optically isolated data link
61. modem 61 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 One particularly useful feature is 34972A s Web Interface Simply enter the IP address of your instrument in your browser s navigation bar to launch the Web Interface The remote control page of the Web Interface shown below allows you to monitor your instrument set up and initiate scans save data to the USB drive and much more For help simply click on the large question mark on the far left side of the screen Agilent Technologies Data Acquisition Switch Unit Status Sean View Data USB Drive Allow Control a Errors USB Drive DMM Monitor Alarms Utility mien ENRE n Slot 1 empty Slot 2 empty Slot 3 20 Ch Mux 34901A Module Overview Bank 1 H Com2 Bank 2 H o oTo Comi Lo Reset Module 309 L 01 Ey 2024 amei 31625 Left click switch 3022 20724 31225 arei to open close P a a Right click switch to 3037 308 i 313 318 view configuration Erag soo Sts 314245 agi 2082 aoli 316 2 s22 62 Chapter 3 System Overview Data Acquisition System Overview Data Logging and Monitoring Keysight BenchLink Data Logger 8 which is included with your 34970A 34972A is a Windows based application that makes
62. module 35 power line rejecting noise 264 preset state 197 programming examples C and C 248 249 Excel 7 0 241 242 243 PT100 RTD 127 266 Q quick start 21 Quick Start Kit 23 R RO RTD default 127 range 127 rack mounting filler panel 38 flange kit 38 lock link kit 38 removing bumpers 37 removing handle 37 sliding shelf kit 38 radio frequency interference 259 random noise 297 range autorange 115 overload 115 selecting 116 ranges by function 2 wire ohms 28 132 4 wire ohms 28 132 ac current 28 133 ac voltage 28 130 de current 28 133 de voltage 28 130 RC protection circuitry 305 Read key 49 51 READ command 95 reading format 104 readings memory storing alarms 139 readings viewing 31 107 real time clock factory setting 166 setting 29 166 rear panel external scanning 111 pictorial overview 9 10 recall power down state 160 reference junction thermocouple definition 124 external reference 124 fixed temperature 124 internal reference 124 reference channel 124 reference thermocouple 269 relative time 104 relay contact protection 305 relay contact resistance 319 relay cycle count clearing 170 estimating relay life 319 reading 169 319 relay life 320 relay maintenance 319 vs load switched 320 relay maintenance system clearing relay count 170 reading relay count 169 319 remote interface 53 55 system remote in
63. 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 also generated if you change the function on the reference channel after selecting the external reference for a thermocouple channel Ifyou 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 For more information on reference junction temperature measurements and associated errors see the sections on pages 267 and 274 124 Chapter 4 Features and Functions Temperature Measurement Configuration 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 e
64. nA to 1A Built in thermocouple reference junction Switching speed of up to 60 channels per second Connects to the internal multimeter For detailed information and a module diagram see page 201 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 34902A 16 Channel Reed Multiplexer 16 channels of 300 V switching Built in thermocouple reference junction Switching speed of up to 250 channels per second Connects to the internal multimeter For detailed information and a module diagram see page 208 Use this module for high speed scanning and high 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 wir
65. 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 the previous scan Therefore the contents of reading memory are always from the most recent scan 140 Chapter 4 Features and Functions Alarm Limits 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 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 145 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 r The indicated HI or LO limit is being configured on the indicated al
66. option assigns the static IP address for the instrument You must disable DHCP in order to set this on the front panel The static IP address is applied when DHCP is disabled If DHCP is enabled DHCP will auto assign the IP address This auto assigned IP address takes precedence over the static IP address assigned with this feature Front Panel Operation IP ADDRESS Setting the Subnet Mask You can set the subnet mask for your LAN connection This menu option assigns a Subnet Mask for the instrument The instrument uses the Subnet Mask to determine whether a client IP address is on the same local subnet You must disable DHCP in order to set this on the front panel When a client IP address is on a different subnet all packets must be sent to the Default Gateway Contact your network administrator to determine whether subnetting is being used and for the correct Subnet Mask Front Panel Operation SUBNET MASK 190 Chapter 4 Features and Functions Remote Interface Configuration 34972A Setting the Default Gateway You can set the default gateway for your LAN connection Contact your network administrator to determine whether subnetting is being used and for the correct address If DHCP is enabled DHCP will auto assign the gateway This auto assigned gateway takes precedence over the static gateway assigned with this menu option You must disable DHCP in order to set this on the front panel Front Panel O
67. or continuous During an Interval Scan see page 96 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 98 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 99 the scan count sets the number of external trigger pulses that will be accepted before terminating the scan During an Alarm Scan see page 100 the scan count sets the number of alarms that will 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 Rcl menu sets the scan count to continuous From the remote interface a Factory Reset RST command sets the scan count to 1 sweep 102 Chapter 4 Features and Functions Scanning Front Panel Operation 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 Ope
68. plug in modules that you ordered are delivered in a separate shipping container 2 Verify that the fuse on the back is set to the proper voltage range for your AC power Connect the power cord and turn on the instrument The front panel display will light up briefly while the instrument performs its power on self test 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 Note that a battery must be installed in the unit in order for it to boot up The battery is installed when you receive the unit from the factory this is only a consideration if you remove the battery for some reason If the instrument does not turn on properly see page 34 23 Chapter 1 Quick Start To Prepare the Instrument for Use 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 84970A 84972A Service Guide for instructions on returning the instrument to Keysight for service 24 Chapter 1 Quick Start BenchLink Data Logger Software BenchLink Data Logger Software The Keysight BenchLink Data Logger 3 software comes standard with the 34970A 34972A if th
69. quote is missing String data not allowed A character string was received but is 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 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 221 214 221 222 223 224 230 310 Chapter 5 Error Messages Execution Errors Trigger deadlock A trigger deadlock occurs when the trigger source is BUS anda 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 genera
70. shown on page 247 into the Send Commands module and reuse the Port Configuration module from the first example page 245 Make any changes necessary to suit your application in the Send Commands module You must 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 GPIB 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 243 Chapter 6 Application Programs Example Programs for Excel 7 0 l Excel 7 0 Example takeReadings Macro UTE Tee UU Te AY TT eV OY ee Ye OY OO Oe OY OY OO Oe OY YOY WY VY WYO Oy Oe oe ve Oy neva nnw This Excel Macro Visual Basic configures the 34970A for scanning with the 34901A 34902A or 34908A multiplexer modules When this subroutine is executed it will 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 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 GPIB interface card installed in your PC with the VISA or VTL library RPh hh a hc r
71. terminals see page 28 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 Default Settling Delay 3 Hz to 300 kHz Slow 1s 20 Hz to 300 KHz Medium 100 ms 200 Hz to 300 kHz Fast 10 ms The instrument selects the medium timeout 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 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 8 Hz 135 Chapter 4 Features and Functions Mx B Scaling Mx B Scaling The scaling function allows you to apply a gain and offset to all readings on a
72. the baud rate Select one of the following 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud 19200 BAUD Select the parity and number of data bits 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 Select the flow control method Select one of the following None no flow control RTS CTS DTR DSR XON XOFF factory setting or Modem FLOW DTR DSR Save the changes and exit the menu 54 OT Interface 2 Chapter 2 Front Panel Overview To Configure the Remote Interface 34972A To Configure the Remote Interface 34972A The instrument is shipped with both a Local Area Network LAN interface and a Universal Serial Bus USB interface Both interfaces can be enabled at the same time and both interfaces are selected when the instrument is shipped from the factory LAN Configuration Select the LAN interface LAN INTERFACE Enable the LAN This is enabled by default LAN ENABLED Configure the instrument LAN settings according the instructions provided by your LAN administrator 55 Qa 2 Interface 3 Interface Chapter 2 Front Panel Overview To Configure the Remote Interface 34972A USB Configuration
73. 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 200 65 Chapter 3 System Overview Data Acquisition System Overview Model Number Module Name Common Uses 34901A 20 Channel Mux with T C Scanning and direct measurement of Compensation temperature voltage resistance 5 frequency and current 34901A onl 34902A 16 Channel Reed Mux with T C using Ae ocean y Compensation 34908A 40 Channel Single Ended Mux Scanning and direct measurement of with T C Compensation temperature voltage and resistance using the internal DMM 34907A Multifunction Module Digital Input Event Counting 34901A 20 Channel Mux with T C Multiplexing of signals to or from Compensation external instruments 34902A 16 Channel Reed Mux with T C Compensation 34908A 40_Channel Single Ended Mux with T C Compensation 34904A 4x8 Matrix Switch 32 Crossppoint Matrix switching 34905A Dual 4 Channel RF Mux 509 50Q high frequency applications lt 2 GHz 34906A Dual 4 Channel RF Mux 75Q 75Q high frequency applications lt 2 GHz 34903A 20 Channel Actuator General purpose switching and control using Form C SPDT switches 34907A Multifunction Module Digital Output Voltage DAC Outputs Chap
74. tutorial 253 Wheatstone bridge strain 295 wire size gauge 256 wiring connections ac current 28 ac voltage 28 dc current 28 dc voltage 28 frequency 28 period 28 resistance 28 RTDs 28 thermistors 28 thermocouples 28 wiring strain relief 27 wiring strip length 27 wiring log 349014 201 34902A 203 34903A 205 34904A 207 34905A 209 34906A 209 34907A 211 34908A 213 Write key 50 52 X XON XOFF annunciator 185 Z ZERO AUTO command 122 356 This information is subject to change without notice Keysight Technologies 2009 2014 Edition 4 August 2014 KEYSIGHT 34972 90001 TECHNOLOGIES www keysight com
75. two banks of 10 channels each Two additional fused channels 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 channel n 10 to provide the source and sense connections The module has a built in thermocouple reference junction to minimize errors due to thermal gradients when measuring thermocouples Backplane Switches Channel Switches Internal 2 P fr OH o1 gt y L DMM Input 98 c y pa u DL 10 a Com Reference 1 TE Junction lt T 99 Bank Switches Sensor 2 gt t Com 4W Sense SH or 11 Internal H i SH DMM Input Lo a oi 20 4W Sense gt 97 Shunt Switches 93 Fuse i P e724 Internal i 5 DMM Input lt ene a Current Channels Current 96 94 Fuse Com Current NOTES e Only one of channels 21 and 22 can be connected 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 Connections to AC line are not recommende
76. 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 Measurement configuration Mx B scaling configuration Alarm configuration 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 procedure 32 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 al
77. you initiate a new scan the instrument clears all previously stored readings To stop a scan press and hold Goan 94 Chapter 4 Features and Functions Scanning To Build a Scan List From the Remote Interface 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 To initiate a scan execute the MEASure READ 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 Keysight 34970A 84972A Programmer s Reference Help for more information on using these commands 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 Each time you initiate a new scan the instrument clears all pre
78. 0 and cc is the channel number Example ROUT CLOSE 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 84970A 84972A 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 84970A 84972A Service Guide to replace the internal battery 224 203 204 221 222 223 224 Chapter 5 Error Messages Instrument Errors 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 34970A 34972A 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 JA
79. 001 300 000 V 0 0020 0 0020 0 0035 0 0030 0 0045 0 0030 0 0005 0 0003 Resistance 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 500nA 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 34901A Only 100 0000 mA lt 0 6 V 0 010 0 004 0 030 0 005 0 050 0 005 0 002 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 1 Year Best Range Accuracy Extended Range Accuracy Temperature Coefficient C 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 200 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 1200 C 1 0 C 200 C to 100 C 15 C 0 03 C N 100 C to 1300 C 1 0 C 200 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
80. 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 4 00 0 50 4 00 0 50 4 00 0 50 0 20 0 02 300 0000 V 3Hz 5Hz 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 34901A Only 1 000000 Al 10 Hz 5 kHz 0 10 0 04 0 10 0 04 0 10 0 04 0 015 0 006 100 0000 mAl 3 Hz 5 Hz 1 00 0 5 1 00 0 5 1 00 0 5 0 100 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 61 2 Digits 5 Digits 42 Digits
81. 0A 34972A 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 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 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 Temperature thermocouple RTD and thermistor Voltage dc and ac up to 300V e Resistance 2 wire and 4 wire up to 100 MQ Current DC and AC up to 1A Frequency and Period up to 300 kHz 74 Chapter 3 System Overview Measurement Input 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 Analog i
82. 10 Hz 20 Hz 0 0 74 x 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 1kHz 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 6 digits Slow AC filter 2 Relative to calibration standards 3 20 over range on all ranges except 300 VAC and 1 A ac rangesand AC current 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 to 100 mV inputs multiply of reading error x 10 7 Specified only for inputs gt 10 mA 328 Chapter 8 Specifications AC Measurement and Operating Characteristics mi AC Measurement and Operating Characteristics AC Measurement Characteristics l True RMS AC Voltage Measurement Method AC coupled True RMS measures the AC component of 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 2 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
83. 1A 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 waw 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 time out 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 30 View 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 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 or
84. 2 34901A Channels 1 through 10 Channels 11 through 20 34902A Channels 1 through 8 Channels 9 through 16 34908A Channels 1 through 20 Channels 21 through 40 305 Chapter 7 Tutorial Actuators and General Purpose Switching Actuators and General Purpose Switching The 34903A Actuator provides 20 independent isolated SPDT single pole double throw or Form C switches This module 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 102 I COM 2 NO 102 2 COM ANO lt 4 10Q COM ANO lt 4 10Q 2 COM 2 NO 102 c 2 COM ZNO lt 4 10Q CE NO Normally Open In the above diagram the resistance is 60Q 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 10Q to 50Q are selected by closing the appropriate channel s on the module 306 Chapter 7 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
85. 202 Chapter 4 Features and Functions 34902A 16 Channel Multiplexer 34902A 16 Channel 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 thermocouple reference junction to minimize errors due to thermal gradients when measuring thermocouples Backplane Switches Channel Switches H Internal DMM Input o l 98 Reference Junction lt T 99 A Sensor Internal H 1009 1009 Bank Switches 1009 a 1009 L 9 DMM Input lt 4W Sense 97 NOTES N 01 08 Com Com 4W Sense 09 16 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 Current measurements on this module will require external shunt resistors Connections to AC line are not recommended unless you provide external transient suppression 203 Chapter 4 Features and Functions 34902A 16 Channel Multiplexer
86. 3 316 manually reset 51 maximum count 154 315 reading count 51 reset mode while scanning 92 reset mode 51 155 scanning 92 Totalize Threshold jumper 154 track mode alarm output lines 146 transducer types 68 tree switch 303 triangle brackets lt gt syntax 89 TRIG SOUR command 97 TRIG TIMer command 97 TRIGGER command 98 TRIGger COUNt command 103 triggering buffering 99 external 99 scan 96 troubleshooting error messages 215 238 true RMS 280 TTL drive digital output 313 tutorial 253 twisted pair cables 67 two wire multiplexers 71 298 two wire ohms 289 355 Index U UNIT TEMP command 123 units temperature 123 with readings 104 unsecure calibration 192 USB Front Panel 180 USB exporting readings 180 USB formatting readings 180 USB importing an instrument configuration 181 Utility key 42 V varistor 306 vertical bar syntax 89 VIEW annunciator 8 View key 31 42 109 143 viewing alarm data 143 readings 107 scanned readings 31 Visual Basic example 241 VM Complete signal 112 voltage DAC output card reset 159 current limitations 159 317 differential error 318 integral error 318 resetting 52 simplified schematic 317 writing 52 voltage dividers 305 voltage measurements 130 ac low frequency filter 131 ac settling time 131 VSWR 311 W Warnings 34901A 201 34902A 203 34903A 205 34904A 207 34908A 212 warranty 2 waveform
87. 5 Error Messages Instrument Errors Settings conflict DMM disabled or missing This command is valid only when the internal DMM is installed and enabled Use the INSTrument DMM command to determine the state of the internal DMM For more information see Internal DMM Disable on page 167 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 167 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 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 degr
88. 8 ecl Switch Life No Load typical 100M 100M 100M 100M 100M Switch Life Rated Load typical l 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 See scanning rate specifications for measurement conditions and rates on each instrument 2 Errors included in the DMM measurement accuracy specifications 3 50Q source 50Q load 4 Isolation within channel 1 to 20 or 21 to 40 banks is 40 dB 5 Thermocouple specifications not guaranteed when 34907A module is present 6 Applies to resistive loads only 7 Thermocouple measurements not recommended with 34908A module due to common LO configuration 333 Chapter 8 Specifications Module Specifications Wi Module Specifications 34905A 34906A RF Multiplexer General 34905A 34906A Number of Channels Dual 1x4 Dual 1x4 500 750 Open Close Speed 60 s Maximum Input Voltage dc AC rms 42V Current dc AC rms 0 7 A Power W VA 20 W DC Characteristics Offset Voltage l lt 6 uV Initial Closed Channel RI lt 0 5Q Isolation ch ch ch earth gt 1GQ Other Switch Life No Load typical 5M Switch Life Rated Load typical 1 100k Temperature Operating 0 C to 55 C Temperature Storage 20 C to 70 C Humidity non condensing 40 C 80 R H
89. 84970A 34972A Programmer s Reference Help Setting up Automatic Logging You can set up the USB drive for automatic logging of readings Front Panel Operation LOG READINGS AUTO OFF Exporting Readings You can export readings from reading memory onto the USB drive Front Panel Operation EXPORT READNG YES NO 181 Chapter 4 Features and Functions USB Drive Front Panel 34972A Formatting Readings You can control how readings are formatted on the USB drive In particular you can choose whether the readings are stored in one large file ROWS FILE AUTO or ina series of files with 64K 1 rows per file ROWS FILE 64K You can also choose whether the files are formatted with a tab comma or semicolon between columns Front Panel Operation Interface FOR READNG ROWS FILE AUTO Interface FOR READNG ROWS FILE 64K Interface FOR EADNG SEP TAB Interface FOR READNG SEP COMMA 00000 D gt pp Pp P wm Interface FOR READNG SEP SEMICOLON Importing an Instrument Configuration You can import an instrument configuration stored in a Keysight BenchLink Data Logger configuration BLCFG file in the root directory of your USB drive Front Panel Operation IMPORT CONFIG 182 Chapter 4 Features and Functions Remote Interface Configuration 34970A Remote Interface Configuration 34970A This section g
90. C filter to the highest frequency limit see page 131 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 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 67 Digits 21 10 PLC lt 0 000001 x Range 6 Digits 24 20 PLC lt 0 0000008 x Range 6 Digits 25 100 PLC lt 0 0000003 x Range 6 Digits 26 200 PLC lt 0 00000022 x Range 6 Digits 26 120 Chapter 4 Features and Functions General Measurement Configuration The instrument 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 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 Advanced INTEG 222P LC To select the ap
91. DC range with 4 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 e 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 1038 SENS FRES RES 100 103 119 Chapter 4 Features and Functions General Measurement Configuration Custom A 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 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 Only the integral number of power line cycles 1 2 10 20 100 or 200 PLCs provide normal mode line frequency noise rejection 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 The only way to control the reading rate for AC measurements is by changing the channel delay see page 105 or by setting the A
92. He Required VISA library 5 This program demonstrates the use of the 34970A Status Registers for an alarm and Operation Complete OPC and for enabling and receiving an SRQ interrupt This program also shows how to configure a scan for bei 10 readings on one channel K FEA TA A A A A A I I I I I I ARR AAA AA AAA I I A I I A I I I I ke include lt visa h gt include lt stdio h gt include lt string h gt ViSession defaultRM Resource manager id ViSession DataAcqu Variable to identify an instrument char reply_string 256 0 string returned from instrument double volt 10 int index count int srqFlag 0 Function prototypes for SRQ handler ViStatus _VI_FUNCH SRQ_handler ViSession DataAcqu ViEventType eventType ViEvent context ViAddr userHdlr void main Open communication with DataAcqu using GPIB address 9 viOpenDefaultRM amp defaultRM viOpen defaultRM GPIB0O 9 INSTR VI_NULL VI_NULL amp DataAcqu Reset instrument to power on and clear the Status Byte viPrintf DataAcqu RST CLS n Configure the Status Registers to generate an interrupt whenever an alarm is detected on Alarm 1 or when the operation is complete viPrintf DataAcqu STATUS ALARM ENABLE 1 n Enable Alarm 1 viPrintf DataAcqu ESE 1 n Enable the Operation Complete bit Enable Status Byte Register bit 1 2 and 5 32 for SRQ viPrintf DataAcqu
93. Hz 300 kHz Input Impedance 1 MQ 2 in parallel with 150 pF Input Protection 300 Vrms on all ranges Frequency and Period Measurement Method Reciprocal counting technique Voltage Ranges Same as AC Voltage function 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 Shunt Resistance 5Q for 10 mA 0 19 for 100 mA 1A Input Protection 1 5A 250 V fuse on 34901A module Measurement Noise Rejection P 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 329 Chapter 8 Specifications System Characteristics Wi System Characteristics 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 300 us 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 Memory Battery Backed 34970A 4 year typical life 34972A User replaceable battery recomme
94. Input Voltage 300 V CAT 1 Maximum Input Current 1 A Maximum Switching Power 50 W 20 S 6mm 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 devices connected to the module 208 Chapter 4 Features and Functions 34905A 6A Dual 4 Channel RF Multiplexers 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 on board SMB connectors or to the SMB to BNC cables provided with the module 98 Bank Switch Comi 99 j Bank Switch Com2 24 NOTES e The 34905A is used for 50Q applications The 34906A is used for 75Q applications mini SMBs 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 209 Chapter 4 Features and Functions 34905A 6A Dual 4 Channel RF Multiplexers
95. Keysight 34970A 34972A Data Acquisition Switch Unit KEYSIGHT User s Guide TECHNOLOGIES NOTICE This document contains references to Agilent Technologies Agilent s former Test and Measurement business has become Keysight Technologies For more information go to www keysight com KEYSIGHT TECHNOLOGIES Notices Keysight Technologies 2009 2014 No part of this manual may be repro duced in any form or by any means including electronic storage and retrieval or translation into a foreign language without prior agreement and written consent from Keysight Technologies as governed by United States and international copyright laws Manual Part Number 34972 90001 Edition 4 August 2014 Printed in Malaysia Keysight Technologies 900 S Taft Ave Loveland CO 80537 USA Adobe the Adobe Logo Acrobat and the Acrobat Logo are trademarks of Adobe Systems Incorporated Microsoft is either a registered trade mark or a trademark of Microsoft Cor poration in the United States and or other countries Windows and MS Windows are U S registered trademarks of Microsoft Corporation Software Updates Licenses Periodically Keysight releases software updates to fix known defects and incorpo rate product enhancements To search for software updates and the latest documenta tion for your product go to the product page at www keysight com find 34970A www keysight com find 34972A A porti
96. LCs Digits Bits 60 Hz 50 Hz NMR 0 02 4 15 400 us 400 ps 0 dB 0 2 5 18 3 ms 3 ms 0 dB 1 5 20 16 7 ms 20 ms 60 dB 2 6 21 33 3 ms 40 ms 90 dB 10 6 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 6 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 0dB 10 dB 4 Signal Gain 8 5 T 30 dB 40 dB 0 1 1 10 Signal Frequency x T 266 Chapter 7 Tutorial Measurement Fundamentals Temperature Measurements 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 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 DC voltage and resistance measurements elsewhere in this chapter The largest source of error in temperature measurements is generally the transducer itself Your measurement requi
97. List below To add channels to the scan list modify scanList and then configure the channel using the CONFigure command r r 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 SendSCPI CONF VOLT DC 110 111 112 Configure three channels for DC volts PUTT EY TT TY UY AY eV ee OY Wee Oe OY OY OY Oe WY VY WYO YOY WY VY Oe OY OY OY OY vee nyo vee oe vee OY Ove vO Oe ev OO SendSCPI ROUTE SCAN amp 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 247 Chapter 6 Application Programs Example Programs for Excel 7 0 Set up the scan trigger parameters after configuring the
98. Low Level Module Control Keys 10 Single Channel Monitor On Off Key 11 View Scanned Data Alarms Errors Menu 12 Shift Local Key 13 Knob 14 Navigation Arrow Keys The Front Panel Menu 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 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 time out after about 20 seconds of inactivity You will be returned to the operation in progress prior to entering the menu 2 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 3 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 4 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 Di
99. N 1 1996 00 00 00 This error is most likely caused by a dead battery memory is battery backed Refer to the 34970A 34972A Service Guide to replace the internal battery 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 TMMediate 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 225 225 226 251 261 271 272 Chapter
100. OFST TO 0 DEFAULT LABEL To make a null measurement and store it as the offset go to SET OFFSET in the menu and turn the knob SET 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 channel CALC SCALE STATE ON 101 To make a null measurement and store it as the offset send the following command CALC SCALE OFFSET NULL 101 138 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 108 205 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 t
101. Q 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 little noise immunity 67 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 500Q Thermistor 2 wire resistance from 109 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 68 Chapter 3 System Overview Data Acquisition System Overview Alarm Limits The 34970A 34972A 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 as
102. 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 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 Front Panel Operation FLOW RTS CTS 187 Chapter 4 Features and Functions Remote Interface Configuration 34972A Remote Interface Configuration 34972A 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 53 For more information on the SCPI commands available to program the instrument over the remote interface see the Keysight 84970A 34972A Programmer s Reference Help 2 All of these menu items are accessed under the top level menu LAN INTERFACE Enabling and Disabling LAN Connectivity You can enable or disable the LAN connectivity If you are not controlling the instrument via LAN it is a good idea to disable LAN connectivity in order to prevent others from connecting to your instrument over the LAN Front Panel Operation LAN ENABLED DISABLED
103. RY 157 Chapter 4 Features and Functions Digital Output Operations 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 You 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 01 SOUR DIG DATA BYTE 10 302 Write to port 02 SOUR DIG DATA WORD 10327 301 Write to both ports 158 Chapter 4 Features and Functions DAC Output Operations DAC Output Operations The multifunction module 84907A 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 where s 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 wil
104. SRE 34 n Enable the interrupt handler for SRQ from the instrument vilInstallHandler DataAcqu VI_EVENT_SERVICE_REQ SRQ_ handler ViAddr 10 viEnableEvent DataAcqu VI_EVENT_SERVICE_REQ VI_HNDLR VI_NULL Configure 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 DataAcqu CONF VOLT DC 10 103 n viPrintf DataAcqu TRIG SOURCE TIMER n viPrintf DataAcqu TRIG TIMER 1 n viPrintf DataAcqu TRIG COUNT 10 n viPrintf DataAcqu CALC LIMIT UPPER 5 103 n viPrintf DataAcqu CALC LIMIT UPPER STATE ON 103 n viPrintf DataAcqu OUTPUT ALARM1 SOURCE 103 n viPrintf DataAcqu INIT OPC n Wait for the instrument to complete its operations so waste time and stay in the program in case there is an SRQ Continued on next page 252 Chapter 6 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 index 0 print i 3 printf srq flag d n srqFlag while srqFlag gt 0 A negative srqFlag indicates scan is done The instrument is done so close the SRQ handler viDisableEvent DataAcqu VI_LEVENT_SERVICE_REQ VI_HNDLR viUninstallHandler DataAcqu VI_EVENT_SERVICE_REQ SRQ_handler ViAddr 10 viPrintf DataAcqu FETCH n
105. Select the USB interface USB INTERFACE Enable or disable the USB interface Select either USB ENABLED or USB DISABLED USB ENABLED View the USB ID String The instrument will display its USB identification USB ID string This is helpful in identifying the device on the USB network Use the left and right arrows above the knob to view the full string USB0 2391 8199 MY01023529 0 INSTR Save the changes and exit the menu 56 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 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 1 TEST_RACK_2 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 STATE2 Store the instrument state The instrument stores all channel configurations alarm values scaling values scan interval setu
106. 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 340 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 Ifyou are operating the internal DMM outside the 23 C 5 C temperature range specified apply an additional temperature coefficient error For DC voltage DC current and resistance measurements you may need to apply an additional reading speed error 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 and range you select as well as
107. 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 130 276 Chapter 7 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 input terminals are both driven by an earth referenced signal V9 then a current will flow through Rg and create a voltage drop V 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 120 for a discussion of integration time i HI aS a l Viest DMM aN i R l AA Lo V i SU eea 250 pF i l v 3 gt 10 GO 1 Where V Common mode float voltage Rs LO lead resistance R Isolation resistance C Isolat
108. Zap 3 x 20000 bandwidth 4 x 3 14159 x 1000000 Total Error 0 09 0 15 1 4 1 6 100 1 4 285 Chapter 7 Tutorial Measurement Fundamentals AC Loading Errors In the AC voltage function the input of the internal DMM appears as a 1 MOQ 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 KQ 10 kHz 100 KQ 100 kHz 10 kQ For low frequencies 100 x Rs Error Roo MO Additional error for high frequencies Error 100 x 1 1 J 2nxF xR 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 258 286 Chapter 7 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 imped
109. a new calibration 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 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 D to scroll through the text of the message Press D again to increase the scrolling speed Storing a calibration message will overwrite any message previously stored in memory 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 Front Panel Operation CAL MESSAGE Remote Interface Operation To store the calibration message send the following command CAL STRING CAL 06 01 98 195 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 memory in the mainframe and does not change when power has been off af
110. able 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 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 44 Interval Interval 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 00020 SCANS 3 Run the scan and store the readin
111. abling 167 169 reading relay count 169 DNS Server 190 DTR DSR flow mode RS 232 185 Dynamic Host Configuration Pro tocol 188 E E5810A LAN to GPIB 61 ERROR annunciator 8 163 216 error messages 215 238 errors ac loading 284 cabling 259 capacitive coupling 301 clearing 163 common mode noise 273 diffusion error 272 frequency measurements 297 loading de voltage 277 348 Index loading input bias current 278 low level ac 261 magnetic fields 260 multiplexing and switching 301 period measurements 297 reading error queue 163 216 RF multiplexing 311 thermal EMF 260 thermocouple calculation 273 thermocouple reference junc tion 272 totalizer 316 example programs C and C 248 Excel 7 0 241 Excel macro example programs 241 Exporting readings to USB 180 Express Exchange program 15 EXT annunciator 8 Ext Trig connector 9 10 99 111 external DMM connections 111 scanning with 111 external reference T C 124 external scanning connections 111 with digital channels 113 external trigger connector 9 10 99 111 scan interval 96 F factory reset state 196 fahrenheit setting units 123 fast ac filter 131 138 134 281 fast timeout 135 FETCh command description 95 filler panel kit rack mounting 38 filter ac signal 131 133 1384 281 firmware revision 34970A 167 plug in modules 167 fixed input range dc voltage 130 fixed reference thermocouple
112. ace by sending the IEEE 488 Group Execute Trigger GET message The following statement shows how to send a GET message TRIGGER 709 Group Execute Trigger Note To stop a scan send the ABORt command 98 Chapter 4 Features and Functions Scanning External Scanning In 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 Input 5 1 5V 2 Ext Trig Input OV Gnd gt 1 us Ext Trig Connector You can specify a scan count which sets the number of external pulses the instrument will accept before terminating the scan See Scan Count on page 102 for more information Ifthe instrument receives an external trigger before it is ready to accept one it will buffer one trigger before generating an error 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 B scaling and alarm limits are applied to measurements during the scan and all data is stored in non volatile memory Front Panel Operation interval EXTERNAL SCAN To initiate the scan press The EXT annunciator turns on as a reminder that an External Scan is in progress When a TTL pulse is received the scan starts and readings are stored in memory To stop scan press and hold
113. ach 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 OPEN T C on the front panel Front Panel Operation To select the thermocouple function on the active channel choose the following items TEMPERATURE THERMOCOUPLI El To select 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 sanea T C CHECK ON To select the reference junction source for the active channel choose one of the following items Advanced INTERNAL REF EXTERNAL REF FIXED REF Note Before selecting an external source be sure to configure channel 01 in the lowest slot for a thermistor or RTD measurement 125 Chapter 4 Features and Functions Temperature Measurement Configuration Remote Interface Operation You can use the MEASure or CONFigure command to select the probe type and thermocouple type For example the following statement configures channel 301 for a J type the rmocouple measurement CONF TEMP TC J 301 You can thermoc channel also use the SENSe command to select the probe type and ouple type For example the fo
114. acteristics on page 327 e AC Accuracy Specifications on page 328 AC Measurement and Operating Characteristics on page 329 System Characteristics on page 830 System Speed Specifications 1 on page 331 Module Specifications 34901A 34902A 34908A 34903A 34904A on page 888 Module Specifications 34905A 34906A on page 334 Typical AC Performance Graphs 34905A 34906A on page 885 Module Specifications 34907A on page 386 e Product and Module Dimensions on page 337 To Calculate Total Measurement Error on page 888 Interpreting Internal DMM Specifications on page 340 Configuring for Highest Accuracy Measurements on page 343 Specifications Chapter 8 Specifications DC Resistance and Temperature Accuracy Specifications mi DC Resistance and Temperature Accuracy Specifications of reading of range m Includes measurement error switching error and transducer conversion error Temperature Function Rangel Test Current or 24 Hour 90 Day 1 Year Coefficient C Burden Voltage 23 C 1C 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 0
115. ad a 16 bit word 8 Port 1 LSB Z C Channel 01 Digital Bit 7 Input gt Bito 8 gt _ Port 2 MSB 2 Channel 02 P D Bit 7 81 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 A2 N 26 Bits Totalize Channel 03 2 Gate Gate You can configure the totalizer to count on the rising edge or falling edge of the input signal The maximum count is 67 108 863 27 1 The count rolls over to 0 after reaching the maximum allowed value You can configure the totalizer to read without affecting the count or reset the count to zero without losing any counts 82 Chapter 3 System Overview Control Output Control Output In addition to signal routing and measurement you can also use the 34970A 34972A 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 84907A 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 starting on page 81
116. alculation 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 267 275 Chapter 7 Tutorial Measurement Fundamentals DC Voltage Measurements To make a useful DC 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 simplified input to the internal DMM is shown below HI Low V N l 12Vcdto i Analog to Digital 7 High V 2 Converter X1 y 100 1 E X10 A Ranging x100 lt LO 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
117. all four output lines choose from the following items FAIL HIGH FAIL LOW 146 Chapter 4 Features and Functions Alarm Limits Remote Interface Operation To clear the specified output lines or to clear all four lines use one of the following commands OUTPUT ALARM2 CLEAR Clear alarm output line 2 OUTPUT ALARM CLEAR ALL Clear all four alarm outputs To select the output configuration for all four output lines 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 147 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 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 Alarms are evaluated continuously on the multifunction module but alarm data is stored in reading memory only during a scan Each time you start a new scan the instrument clears all readi
118. ances 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 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 287 Chapter 7 Tutorial Measurement Fundamentals Measurements Below Full Scale You can make the most accurate AC measure
119. annel channel 01 for a thermistor or RTD measurement This error is also generated if you change the function on the reference channel channel 01 after selecting the external reference source on a thermocouple channel Channel not able to perform requested operation The channel is unable to perform the requested operation Incorrectly formatted channel list The channel list is not formatted correctly Examples of proper formats are shown below 321 channel 21 on the module in slot 300 221 222 channels 21 through 22 on the module in slot 200 121 122 222 321 322 channels 21 and 22 on the module in slot 100 channel 22 on the module in slot 200 and channels 21 22 on the module in slot 300 228 401 402 403 404 405 406 407 408 409 410 411 412 413 Chapter 5 Error Messages Instrument Errors Mass storage error failed to create file The file was not created on the USB drive Mass storage error failed to open file The file was not opened on the USB drive Mass storage error failed to close file The file was not closed on the USB drive Mass storage error file write error The file data was not written on the USB drive Mass storage error file read error File data was not read from the USB drive Mass storage error file write error File data was not flushed to the USB drive Mass storage error failed to remove file The instrument was unable unable to delete the
120. are conversions PT100 is a special label that is sometimes used to refer to an RTD with a 0 00385 and R 1000 The resistance of an RTD is nominal at 0 C and is referred to as Rg The 34970A 34972A can measure RTDs with R values from 49Q to 2 1 KQ 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 Thermistor Measurements A thermistor is constructed of materials that non linearly changes resistance with changes in temperature 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 The thermistor conversion routines used by the 34970A 34972A are compatible with the International Temperature Scale of 1990 ITS 90 268 Chapter 7 Tutorial Measurement Fundamentals Thermocouple Measurements A thermocouple converts temperature to voltage When two wires composed o
121. area is provided on the 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 reactive loads Although many types of contact protection networks can be used only RC networks and varistors are described in this section Relay 1 1 1 N d H N Contact Varistor i 1 1 P KU RC Protection Networks When designing RC protection networks the protection resistor R is selected as a compromise between two resistance values The minimum value of R is determined by the maximum acceptable relay contact current Lmax For the 34903A the maximum allowable relay current Imax is 1A DC or AC rms Thus the minimum value for R is V I where V is the peak value of the supply voltage V _ V R lt P 2 max 307 Chapter 7 Tutorial Actuators and General Purpose Switching The maximum value for R is usually made equal to the load resistance R Therefore the limits on R can be stated as V max lt R lt RL Note that the actual value of the current in a circuit is determined by the equation fice o Ri Where V is the peak value of the source voltage and Ry is the resistance of the load The value for I will be used to det
122. arm shown H while in the Alarm menu An alarm has occurred on one or more channels The behavior of the alarm output lines tracks the alarm annunciators on the front panel ILARA The alarm output lines have been cleared but alarms remain in the queue 141 Chapter 4 Features and Functions Alarm Limits In 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 Keysight 34970A 84972A Programmer s Reference Help for more information 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 For details on configuring alarms on the multifunction module see Using Alarms With the Multifunction Module on page 148 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 Front Panel Operation To select the alarm for use on the active channel choose from the following items NO ALARM USE ALARM 1 USE ALARM 4 Then choose from the following alarm conditions HI LO ALARMS HI ALARM ONLY LO ALARM ONLY T
123. arm limits and does not turn off alarms 0 250 000 TC 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 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 48 Chapter 2 Front Panel Overview To Read a Digital Input Port To Read a Digital Input Port The multifunction module 84907A 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 press the key and select USE BINARY or USE DECIMAL 01010101 DIN Binary Display Shown The bi
124. ast 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 109 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 Minimum 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 follow
125. ate 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 144 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 these 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 T 9 Z ok 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 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 n
126. ayed channel Mx B scaling is enabled on displayed channel HI or LO alarm condition has occurred on indicated alarms To review the display annunciators hold down the key as you turn on the instrument The 34970A Rear Panel at a Glance a P 2 3 4 L oy l E 0 J t id he 1 Fr mal J S F oH J E T P aa 3 8 T oyu if Noe T 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 for pinouts see pages 99 and 145 7 GPIB IEEE 488 Interface Connector 3 RS 232 Interface Connector Use the Menu to e Select the GPIB or RS 232 interface see chapter 2 e Set the GPIB 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 The 34972A Rear Panel at a Glance
127. bered s03 where s represents the slot number You can configure the instrument to count on the rising edge or falling edge of the input signal 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 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 Input Signal A Rising Edge Gate Signal High True Totalizer Input Add to Total 153 Chapter 4 Features and Functions Totalizer Operations 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 The maximum count is 67 108 863 226 1 The count rolls over to 0 after reaching the maximum allowed value You can configure t
128. buffer contained data from a previous command the previous data 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 223 111 112 113 201 202 Chapter 5 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 scc 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 scc where s is the slot number 100 200 or 30
129. c 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 register bit is set and new readings will overwrite the first readings stored the most recent readings are always preserved 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 The instrument 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 107 Chapter 4 Features and Functions Scanning 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 stam
130. ch 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 304 Chapter 7 Tutorial Low Level Signal Multiplexing and Switching The 34901A and 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 e Bank Switch l Xe N Fd A AN di Channel gael Switch Source f Source l _ Bank Switch W e gt s x X Cadj SAR Bank 2 Channel Switch Source Source DMM 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
131. channels in the scan list using the CONFigure command The following commands configure the scan interval SendSCPI TRIG COUNT amp StrS numberScans SendSCPI TRIG SOUR TIMER SendSCPI TRIG TIMER amp Str ScanInterval Cells 2 1 Start Time Put headings on spreadsheet Cells 4 1 Channel Put headings on spreadsheet 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 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 1 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
132. characters 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 Front Panel Operation NAME STATE STORE STATE RECALL STATE 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 select LAST PWR DOWN to recall the state of the instrument at the power down To configure the instrument to recall the power down state or issue a Factory Reset when power is restored select from the following m PWR ON LAST PWR ON RESET 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 2 31415 161 Chapter 4 Features and Functions System Related Operations To assign a name to a 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 RECall AUTO OFF 162 Chapte
133. command 95 connections 2 wire resistance 28 4 wire resistance 28 ac current 28 ac voltage 28 de current 28 de voltage 28 frequency 28 period 28 RTD 28 thermistor 28 thermocouples 28 connector location Alarm output 9 10 145 Channel Advance 9 10 Channel Closed 9 10 Ext Trig 9 10 99 GPIB 9 RS 232 9 connector pinout alarm output 145 contact debounce totalizer 316 protection 305 resistance 319 continuous scan count 102 conversion accuracy RTD 265 thermistor 265 thermocouple 265 copying channel configuration 32 correlated noise 261 285 count calibration 195 clearing relay cycles 170 reading relay cycles 169 319 347 Index count scan continuous 45 102 default value 45 102 settings 45 102 count down time 97 counter adding to scan list 51 manually reset 51 reading count 51 reset mode 51 crest factor defined 282 crosspoint switching 72 current limitation DAC 159 317 current measurements ac low frequency filter 133 281 ac settling time 133 281 burden voltage 288 connections 28 low frequency filter 133 281 measurement ranges 28 133 valid channels 133 custom label Mx B displaying character 137 valid characters 137 cycles clearing relay count 170 reading relay count 169 319 D DAC output 34907A current limitations 159 317 differential error 318 integral error 318 simplifi
134. d channel 04 or 05 Enter the output voltage editor 00 000 V DAC Set the desired output voltage Use the knob and C or gt keys to edit the individual digits 05 250VDAC 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 E 52 Chapter 2 Front Panel Overview To Configure the Remote Interface 34970A To Configure the Remote Interface 34970A The 34970A is shipped with both an GPIB IEEE 488 interface and an RS 282 interface Only one interface can be enabled at a time The GPIB interface is selected when the instrument is shipped from the factory GPIB Configuration 1 Select the GPIB interface GPIB 488 2 Select the GPIB address PARASE You can set the instrument s address to any value between 0 and 30 The factory setting is address 9 ADDRESS 09 3 Save the change and exit the menu Interface Note Your computer s GPIB interface card has its own address Be sure to avoid using the computer s address for any instrument on the interface bus Keysight s GPIB interface cards generally use address 21 53 Chapter 2 Front Panel Overview To Configure the Remote Interface 34970A RS 232 Configuration Select the RS 232 interface RS 232 Select
135. d 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 Veco 12 VDC Imax lout low X Safety factor 1 mA x 0 5 0 5 ma R Vee _ 12 Imax 0 0005 The value of the logic high level with the external 24 KQ pull up resistor is calculated as follows 24 kQ R 24 kQ Vhioh Voo x ein 12x 24ka 8 47 VDC 3 K Rexternal As Rexternal 24 KQ 10 kQ Driving External Switches You can use two digital output channels to control an external switch For example you can drive the Keysight 876X series of microwave switches using an external power supply and two digital output channels The state of the 2 to 1 multiplexer is changed by setting the appropriate output bit low 0 Digital Output Channel Keysight 876X Microwave Switch aa 24 Volt 2 A Power m Supply J a z CLI 316 Chapter 7 Tutorial Multifunction Module Totalizer The 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 OY _ is Input Signal MN 1V to 42V TN lo z pb Counter Data Gate A Input Signal
136. d 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 101 219 114 121 123 124 128 131 134 138 Chapter 5 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 Numeric overflow A numeric parameter was found whose exponent was too large for this command Exa
137. d the life of the relay is reduced Replacement Strategy There are essentially two strategies that you can use for preventive 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 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 34970A 34972A Relay Maintenance System to track and even predict relay failures 323 324 DC Resistance and Temperature Accuracy Specifications on page 326 DC Measurement and Operating Char
138. d unless you provide external transient suppression 201 Chapter 4 Features and Functions 34901A 20 Channel Multiplexer WIRING LOG Slot Number 0100 200 4300 EH Function Comments ISNF HI a osy 2 11 12 clue gael 13 14 15 16 17 18 19 20 H COM Not Used L COM Current Channels Only 21 22 COM L COM Not Used 4W Sense Channels are paired to Channel n 10 HI LH Leola eal ae EH H WH 1 ole r e all alt ae i pn DQ Refer to the diagrams on page 27 to connect wiring to the module Maximum Input Voltage 300 V CAT 1 Maximum Input Current 1 A 20 AWG Typical Maximum Switching Power 50 W m TI ae 44X35 diL7 OH ZOH 6mm 2 C C WARNING To prevent electrical shock use only wire a J 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 H TH WH WH WAT
139. der 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 C and D to choose the data you want to view for the selected channel as shown in the table below Jana 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 WY 4 99th Most Recent Reading on Channel 31 Measure 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
140. digit multimeter accuracy stability and noise rejection Up to 60 channels per instrument 120 single ended channels Reading rates up to 500 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 GPIB EEE 488 interface and RS 232 interface are standard on the 34970A Local Area Network LAN and Universal Serial Bus USB are standard on the 34972A SCPI Standard Commands for Programmable Instruments compatibility Keysight 34970A 34972A Data Acquisition Switch Unit that St beat sat The Front Panel at a Glance Configure 3 wsrsus me 4 amp H mas ere 7 4 A 5 H aem isvenees 8 Alerm Gut Utility RE Agilent 2A SWITCH UNIT Lee pp 5 ven N S Gu e stl 2 whale fe a2 of duces miai A ic i 12 13 id Denotes a menu key See the next page for details on menu operation 1 State Storage Remote Interface Menus 2 Scan Start Stop Key 3 Measurement Configuration Menu 4 Scaling Configuration Menu 5 Alarm Alarm Output Configuration Menu 6 Scan to Scan Interval Menu 7 Scan List Single Step Read Key 8 Advanced Measurement Utility Menus 9
141. e Clear the state of the four alarm output lines Select the Latch or Track mode for the four alarm output lines Select the slope rising or falling edge for the four alarm output lines 41 Chapter 2 Front Panel Overview Front Panel Menu Reference Configure the event or action that controls the scan interval e Select the scan interval mode interval manual external or alarm Select the scan count Configure the advanced measurement features on displayed channel Set the integration time for measurements on the displayed channel Set the channel to channel delay for scanning Enable disable the thermocouple check feature T C measurements only Select the reference junction source T C measurements only Set the low frequency limit ac measurements only 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 Select which edge is detected rising or falling for totalizer operations Configure system related instrument parameters Set the real time system clock and calendar Query the firmware revisions for the mainframe and installed modules Select the instrument s power on configuration last or factory reset Enable disable the internal DMM Secure unsecure the instrument for calibration View readings alarms and error
142. e Files are automatically named After a scan finishes you can export reading memory to your USB drive up to 50 000 readings 3 Setup of your instrument based on channel configurations specified in Keysight BenchLink Data Logger Keysight BenchLink Data Logger allows you save configuration BLCFG files on the USB drive You can then import the file on the USB drive into your instrument 174 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A There are two annunciators related to the USB drive MEM on Indicates that a USB drive is connected to the 34972A MEM flashing Indicates the the USB drive is either streaming data to USB logging copying from reading memory to USB exporting or importing a configuration from Keysight BenchLink Data Logger AUTO on Indicates that logging is active To avoid data loss or incomplete instrument configuration do not remove the USB drive while MEM is flashing 4 Management of files on the USB drive via File Transfer Protocol FTP You would typically use FTP to download and delete files from the USB drive attached to the 34972A A typical FTP session is shown below From a command prompt enter FTP AAA BBB CCC DDD to start the FTP session Use the numbers of your instrument s IP address in place of AAA BBB CCC DDD The software will ask for a user name and password The user name is Anonymous and the password is any string such as xy
143. e UY OY OY Oe AY VY Oe OY OY OY Oy OY WYO Oe OY OY OO YOY OY WYO WYO Oe OY WY Ov ve ve oe vo nyo veo ve eee This subroutine is used to create delays The input is in seconds and fractional seconds are allowed TOSI TIT TT TTT TT TT Tee Sub delay delay_time As Single Dim Finish As Single Finish Timer delay_time Do Loop Until Finish lt Timer End Sub 246 Chapter 6 Application Programs Example Programs for Excel 7 0 l Excel 7 0 Example ScanChannels Macro WOVE TUTTE OUT NU TTT TT Te UY UY AY Ve Ty ey YY Oe vee Oe Ye OY Oe Oe Oe OY OY WY VY We OY OY WY VY Oe OY OO Oe OY Oyo ve veo nove eo ve OO OO nnn This Excel Macro Visual Basic configures the 34970A for scanning with the 34901A 34902A or 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 GPIB interface card installed in your PC with the VISA or VTL library nunnu NU Ue TT Ue UY OY Oe Uy ey ey VOY vee Oe OY OY Oe Oe Oe OY OY WYO Oe OY OY OY Oe OY OY Oey vee ove ny neva ev Oe Ov ev Oe nnn Option Explicit Sub ScanChannels Dim columniIndex As Int
144. e conversion accuracy 265 temperature measurements RTDs 127 thermistors 129 thermocouples 124 temperature units 123 terminal connections ac current 28 ac voltage 28 de current 28 de voltage 28 frequency 28 period 28 resistance 28 RTDs 28 thermistors 28 thermocouples 28 wire strain relief 27 wire strip length 27 thermal EMF errors 260 thermistors connections 28 conversion accuracy 265 measurement tutorial 266 measurement units 123 types supported 28 123 Thermocouple Check feature 125 thermocouples calculation error 273 color codes 271 connections 28 conversion accuracy 265 diffusion error 272 external reference 124 fixed reference 124 internal reference 124 isothermal block 124 measurement tutorial 267 measurement units 123 metals used 271 probe accuracy 271 reference junction error 272 reference junction 124 shielding 273 shunt impedance 273 temperature range 271 Thermocouple Check 125 types supported 28 thermoelectric voltages 260 threshold totalize 154 156 time clock factory setting 166 setting the 29 166 time stamp absolute 104 relative 104 timeout low frequency 135 torroid 259 totalize threshold 154 hardware jumper 315 129 totalizer ac vs TTL threshold 154 adding to scan list 51 155 block diagram 315 clearing the count 156 contact bounce 316 counting on falling edge 153 counting on rising edge 153 errors 316 gate signal 15
145. e internal DMM is ordered and provides the basic data logger capabilities Or for increased capabilities purchase the optional Keysight BenchLink Data Logger Pro software This application provides advanced data logging and decision making with no programming required For system requirements and additional details on the features of the software refer to the specifications in chapter 8 BenchLink Data Logger 3 Software Installation Procedure Microsoft Windows Vista XP 2000 1 Insert the 34825A Product CD ROM into your drive 2 From the Product CD ROM window that is displayed locate Keysight BenchLink Data Logger 3 Software in the Software group 3 Click on Install and follow the instructions as prompted by the installation utility A representative screen of the software is shown below 25 Chapter 1 Quick Start BenchLink Data Logger Software ie Ue Yer ow Devt bwin aeee Se ojeju AIL aw cee in of calm Le e o S 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 languages 26 Chapter 1 Quick Start To Connect Wiring to a Module To Connect Wiring to a Module 1 Remove the module cover 2 Connect wiring to
146. e 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 12 34903A 20 Channel Actuator General Purpose Switch 300 V 1 A actuation and switching SPDT Form C latching relays Breadboard area for custom circuits For detailed information and a module diagram see page 205 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 60 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 34904A 4x8 Two Wire Matrix Switch e 32 two wire crosspoints Any combination of inputs and outputs can be connected at a time 300 V 1 A switching For detailed information and a module diagram see page 207 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
147. easurement Fundamentals 265 Low Level Signal Multiplexing and Switching 300 Actuators and General Purpose Switching 306 Matrix Switching 310 RF Signal Multiplexing 312 Multifunction Module 314 Relay Life and Preventive Maintenance 321 Chapter 8 Specifications DC Resistance and Temperature Accuracy Specifications DC Measurement and Operating Characteristics 327 AC Accuracy Specifications 328 AC Measurement and Operating Characteristics 329 System Characteristics 330 System Speed Specifications 1 331 System Speed Specifications 332 Module Specifications 333 Module Specifications 334 Typical AC Performance Graphs 335 Module Specifications 336 Product and Module Dimensions 337 To Calculate Total Measurement Error 338 Interpreting Internal DMM Specifications 340 Configuring for Highest Accuracy Measurements 343 326 U9 U09 19 Quick Start Quick Start One of the first things 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 the SHIFT annunciator will turn on Then press the key that has the desired label below it For example to select t
148. ect 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 6 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 340 Chapter 8 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 6 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 internal DMM s measurement
149. ecting 116 measurement resolution half digit 117 selecting 118 vs integration time 120 measurement tutorial 253 medium ac filter 131 133 281 medium frequency timeout 135 MEM annunciator 8 memory reading scanned readings 107 viewing alarm data 143 viewing scanned data 31 menus front panel 7 39 summary 41 message calibration 194 errors 215 238 front panel display 165 Microsoft Visual C 248 microwave switches driving 314 MIN annunciator 8 minimum reading during scan 91 modem flow control mode RS 232 186 module description 34901A 200 34902A 202 34903A 204 34904A 206 34905A 208 34906A 208 34907A 210 34908A 212 module information default settings 198 firmware revision 167 reading relay count 169 Mon key 44 172 MON annunciator 8 Monitor function definition 171 scan on alarm 101 172 while scanning 91 with alarms 171 with Mx B scaling 171 multiplexer types 298 multiplexers errors 301 four wire 71 300 one wire single ended 71 298 two wire 71 298 VHF 71 Mx B key 41 46 Mx B scaling custom label 46 137 default gain M 136 138 default offset B 136 138 equation used 136 interaction with alarms 136 null stored as offset 136 setting gain M 46 138 setting offset B 46 138 strain measurements 295 valid gain M values 137 valid offset B values 137 while scanning 91 136 N name stored states 57 noise ca
150. ed 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 Nickel Chromium Silicon Nisil Nickel Silicone Magnesium N A Not Available 273 Chapter 7 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 diff
151. ed schematic 317 writing to 52 data acquisition overview 60 data bits RS 232 factory setting 184 selecting 184 DATA LAST command 110 DATA POINts command 110 DATA REMove command 110 date calendar factory settings 166 setting 29 166 de current connections 28 measurement ranges 28 de voltage bias current 278 common mode noise 274 connections 28 injected current 276 input resistance 130 277 loading errors 277 measurement ranges 28 130 signal conditioning 274 decimal format digital input 49 151 default delays channel delays 106 Default Gateway 190 delay channel delay 105 DHCP 188 dielectric withstand voltage 255 differential error DAC 318 diffusion error 272 digital channels external scan ning 113 digital input 34907A 8 bit vs 16 bit operations 151 adding to scan list 49 151 binary format 49 151 block diagram 210 card reset 151 152 decimal format 49 151 scanning 92 simplified schematic 312 using alarms 148 digital output 34907A 8 bit vs 16 bit operations 157 binary format 50 157 card reset 157 decimal format 50 157 driving microwave switches 314 simplified schematic 313 sink current 313 TTL drive capability 313 digits number of 117 vs integration time 120 DIN IEC 751 123 disabling internal DMM 112 display annunciators 8 enable disable 165 text message 165 dissimilar metals 260 DMM internal block diagram 263 enabling dis
152. ed 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 105 293 Chapter 7 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 are 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 in
153. ee symbol on the front panel Not able to accept 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 226 281 291 292 301 303 305 Chapter 5 Error Messages Instrument Errors 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 167 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 channe
154. eeps worth of data on an external USB drive Memory lost non volatile settings USB drive Data in non volatile memory was lost or corrupted USB logging enable row limit and column separator will be set to defaults Configuration import aborted Reconfiguration of the instrument was aborted Configuration import failed This is a summary error that will be generated if ANY other errors were reported during configuration import Invalid import file The instrument did not recognize the USB configuration import file Import file cardset does not match instrument The current instrument configuration does not match the cardset expected by the USB import file Operation not allowed in a configuration import file An illegal command was used inside the USB import file No readings to export Reading memory is empty nothing was exported to the USB drive Unable to fetch measurement config from internal processor The instrument was unable to fetch measurement configuration data from the secondary processor due to a communications error Internal processor returned an invalid measurement config Configuration data returned by secondary processor was bad Measurement configuration could not be determined 232 470 471 472 473 Chapter 5 Error Messages Instrument Errors Measurement was reconfigured Cannot save configuration data Measurement configuration no longer agrees with the corresponding set of readings Configuration
155. eger 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 r yy NSN NN OUT UUTUE Te Ue UU AY Ve VY ey OY OY ee YOY OY OOOO OY OV Oe OY WO WY Weve OY ny Oe oe eo nye oe oe eevee eve To change the GPIB address modify the variable VISAaddr below VISAaddr 9 OpenPort Open communications on GPIB SendSCPI RST Issue a Factory Reset to the instrument TU TET UY UY Te OY TT eV OY Oe ey Ye OY OY OO Oe OY OY OO OY UY OY Ov Oe WO Oe ve oe ny neva vo ny ne oven OO SET UP Modify this section to select the scan interval the scan count and channel delay F 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 scan
156. end data it continues sending data until the XOFF character 13H is received When the XON character 11H is received the instrument resumes sending data 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 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 186 Chapter 4 Features and Functions Remote Interface Configuration 34970A 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
157. entals 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 Dra a ee aa E ara a toto oh Where Vs Ideal DUT voltage Rs DUT source resistance Ri Input resistance 10 MQ or gt 10 GQ 100 x RS y Error R T 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 130 279 Chapter 7 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 currents 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 Where I DMM bias current R DUT source resistance R Input resistance 10 MQ or gt 10 GQ C DMM input capacitance Error V Ip X Rs 280 HI o LOo Chapter 7 Tutorial Measurement Fundamentals AC Voltage Measurements The main purpose of an AC front end is to change an AC voltage input into a DC voltage which can be measured by the
158. ents are taken only during a scan and only on those channels which are included in the scan list The x sample annunciator turns on during each measurement 90 Chapter 4 Features and Functions Scanning 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 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 You can read the contents of memory at any time even during a scan Reading memory is not cleared when you read it 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 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 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 In the Monitor function the instrument takes readings as often as it can on a single channel even during a scan see Single Channel Monitoring on
159. 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 342 Chapter 8 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 Set the resolution to 6 digits you can use the 6 digits slow mode for further noise reduction Set the input resistance to greater than 10 GQ for the 100 mV 1 V and 10 V ranges for the best DC voltage accuracy Use 4 wire ohms and enable offset compensation for the best resistance accuracy AC Voltage and AC Current Measurements Set the resol
160. er 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 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 102 for more information e Mx B 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 count to 1 sweep From the front panel a Factory Reset Sto Rcl 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 Front Panel Operation To select interval scanning and set a scan interval time hour minutes seconds choose the following item INTERVAL SCAN To initiate 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 To stop a scan press and hold 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
161. er Count The multifunction module 84907A 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 totalizer 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 Feo 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 Note To add a totalizer channel to a scan list press and select the TOT READ choice 51 gt S Chapter 2 Front Panel Overview To Output a DC Voltage To Output a DC Voltage The multifunction module 84907A 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 displaye
162. eriod 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 R 1009 5 kQ Automatic Delay Default Setting Autorange 5 digits 1 PLC 10 MQ fixed for all DCV ranges 20 Hz medium Automatic Delay Default Setting Autorange 5 digits 1 PLC off Automatic Delay Default Setting Autorange 5 digits frequency 6 digits period 20 Hz medium Automatic Delay Default Setting Autorange 5 digits 1 PLC 20 Hz medium Automatic Delay 199 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 8 34901A 20 Channel Multiplexer on page 201 34902A 16 Channel Multiplexer on page 203 34903A 20 Channel Actuator on page 205 34904A 4x8 Matrix Switch on page 207 e 34905A 6A Dual 4 Channel RF Multiplexers on page 209 34907A Multifunction Module on page 211 34908A 40 Channel Single Ended Multiplexer on page 213 200 Chapter 4 Features and Functions 34901A 20 Channel Multiplexer 34901A 20 Channel Multiplexer This module is divided into
163. ermine the value of the protection capacitor C 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 determining the minimum allowable circuit capacitance is Cot gt 1 300 x L where L is the inductance of the load and I 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 C 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 308 Chapter 7 Tutorial Actuators and General Purpose Switching Using Attenuators Provisions have been made on the 34903A circuit board for installing simple attenuators or filter networks An attenuator is composed of
164. ert your own components but there are no circuit board traces here You must add your own circuitry and signal routing 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 01 205 Chapter 4 Features and Functions 34903A 20 Channel Actuator WIRING LOG Slot Number 0100 0200 0300 cy Comments DAIDODODOOOE H NO Normally Open NC Normally Closed Refer to the diagrams on page 27 to connect wiring to the module Maximum Input Voltage 300 V CAT 1 Maximum Input Current 1 A Maximum Switching Power 50 W ENG Typical 6mm a j A WARNING To prevent electrical shock use only wire J that is rated for the highest voltage applied to any channel fo Before removing a module cover turn off all power to external devices connected to the module 206 Chapter 4 Features and Functions 34904A 4x8 Matrix Switch 34904A 4x8 Matrix Switch
165. erture time select INTEGRATE T from the Advanced menu and then specify a value in seconds for the active channel advanced INTEGRATE T Remote Interface Operation You can set the integration time using the SENSe commands For 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 SENSe commands For example the following statement specifies an aperture time of 2 ms for resistance measurements on channel 104 SENS RES APER 0 002 104 121 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 Applies to temperature DC voltage 2 wire ohms and DC current measurements only Autozero is enabled when you select 4 wire ohms measurements The autozero mode is set indirectly when you set the resolution and integration
166. es 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 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 Dielectric Withstand Voltage Must be high enough for your application To prevent electrical shock or equipment damage insulate all channels to the highest potential in the system It is recommended that you use wire with 600 V rated insulation 257 Chapter 7 Tutorial System Cabling and Connections 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 5mQ 16 10 mQ 18 15 mQ 20 20 mQ 22 30 mQ 24 50 mQ Recommended wire size for the screw terminals on 84970A 384972A plug in modules 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 ca
167. esistance 100 x Vp Vs Error Sources of Error in AC Current Measurements Burden voltage errors which apply to DC 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 290 Chapter 7 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 a known DC current to an unknown resistance and measuring the DC voltage drop ae To Amplifier and a p i Analog to Digital Runknown hsc ne Converter 3 iestr LO O 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
168. ew scan or cycling power 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 145 Chapter 4 Features and Functions Alarm Limits 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 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 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 YF Falling Edge Rising Edge Note Changing the slope of the output lines may cause the lines to change state 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
169. f 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 Ne 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 this 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 DMM s input terminals and to hold the second thermocouple at a known temperature 269 Chapter 7 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 Cu A gt
170. ferenced Signal toning Converter Section A Optical Isolators The internal DMM can directly make the following types of measurements Each of these measurements is described in the following sections of this chapter Temperature thermocouple RTD and thermistor Voltage dc and AC up to 300V e Resistance 2 wire and 4 wire up to 100 MQ Current de and AC up to 1A Frequency and Period up to 300 kHz 265 Chapter 7 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 present 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 ee Integration Time P
171. flatness DAC convergence failed Cal AC low frequency convergence failed Cal AC low frequency correction out of range Cal AC rms converter noise correction out of range Cal 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 237 747 34970A only 747 34972A only 748 34970A only 748 34972A only 749 Chapter 5 Error Messages Calibration Errors Config data lost HP IB address Calibration failed Config data lost RS 232 Cal checksum failed internal data DMM relay count data lost 238 901 902 903 904 905 906 907 908 910 911 912 913 914 915 916 Chapter 5 Error Messages Plug In Module Errors Plug In Module Errors NOTE The following error messages indicate possible hardware failures within the instrument If any of the following errors occur contact your nearest Keysight Service Center for repair Module hardware Module hardware Module hardware Module hardware Module hardware Module hardware Module hardware Module hardware Module reported an unknown module type Module reported command buffer overflow unexpected data received missing stop bit data overrun protocol violation early end of data missing end of data module srq signal stuc
172. formation on channel delay see page 105 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 10 ohms when compared to PTFE insulators 1018 ohms Leakage from nylon or PVC insulators can easily contribute a 0 1 error when measuring a 1 MQ resistance in humid conditions The table below shows several common insulating materials and their typical resistances Insulating Material Resistance Range Moisture Absorbing PTFE 1 TQ to 1 PQ N Nylon 1 GO to 10 TQ Y PVC 10 G2 to 10 TQ Y Polystyrene 100 GQ to 1 PQ N Ceramic 1 GQ to 1 PQ N Glass Epoxy FR 4 G 10 1 GO to 10 TQ Y Phenolic Paper 10 MQ to 10 GO Y 294 Chapter 7 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 BenchLink Data Logger 3 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 ei
173. 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 Mx B scaling and alarm limits are applied to measurements during the scan and all data is stored in non volatile memory 100 Front Panel Operation SCAN ON ALARM To enable the Monitor function select the desired channel and then press ro To initiate the scan press Chapter 4 Features and Functions Scanning When an alarm event occurs the scan starts and readings are stored in memory Note To stop a scan press and hold Remote Interface Operation The following program segment configures the instrument to scan when an alarm occurs TRIG SOURCE ALARM1 TRIG COUNT 2 CALC LIM UPPER 5 103 CALC LIM UPPER STATE ON 103 OUTPUT ALARM1 SOURCE 103 ROUT MON 103 ROUT MON STATE ON INIT Select the alarm configuration Sweep the scan list 2 times Set the upper limit Enable the upper limit Report alarms on Alarm 1 Select monitor channel Enable monitoring Initiate the scan Note To stop a scan send the ABORt command 101 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
174. g 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 Any channel that can be read by the instrument can also be included in a scan 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 Scanning is allowed with the following modules 34901A 20 Channel Multiplexer 34902A 16 Channel Multiplexer 34907A Multifunction Module digital input and totalizer only 34908A 40 Channel 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 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 Measurem
175. g 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 s AR R The Gage Factor GF indicates the sensitivity of a strain gage and is a measure of the fractional resistance change per strain GF AR R e Devices with a higher gage factor will exhibit a greater 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 296 Chapter 7 Tutorial Measurement Fundamentals Making Strain Gage Measurements A Wheatstone bridge is commonly used to enable instruments wi
176. ge Press 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 163 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 self 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 Ifthe complete self test is successful PASS is displayed on the front panel If the self test fails FAIL is displayed and the ERROR annunciator turns on See the 34970A 34972A Service Guide for instructions on returning the instrument to Keysight for service 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 Remote Interface Ope
177. gs in memory 45 Measure 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 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 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 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 0 000 000 VDC Set Offset 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 46 Alarm Alarm Chapter 2 Front Panel Overview To Configure Alarm Limits To Configure
178. h which the instrument is in compliance by sending a command from the remote interface You cannot query the SCPI version from the front panel 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 0 173 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A Mass Memory USB Subsystem 34972A This section gives information on the mass memory subsystem 34972A only The mass memory subsystem enables you to capture data to or import an instrument configuration from a USB drive connected to the instrument s USB port General Capabilities The mass memory subsystem suppports the following capabilities 1 Automatic streaming of scanned data to USB drive during scan e Files are automatically named Data is logged to USB drive and reading memory simultaneously Most internal operations of the instrument continue to operate on reading memory If you are using TRIGger COUNt INFinity and capturing more than 50 000 readings reading memory will fill and then overflow discarding the oldest data The USB streaming will continue after reading memory overflows allowing you to capture all of the data up to 282 sweeps or up to the limits imposed by the USB drive 2 Copying of data from reading memory to USB drive
179. hapter 4 Features and Functions SCPI Language Conventions 89 Scanning 90 Scanning with External Instruments 111 General Measurement Configuration 115 Temperature Measurement Configuration 123 Voltage Measurement Configuration 130 Resistance Measurement Configuration 132 Current Measurement Configuration 133 Frequency Measurement Configuration 135 Mx B Scaling 136 Alarm Limits 139 Digital Input Operations 151 Totalizer Operations 153 Digital Output Operations 157 DAC Output Operations 159 System Related Operations 160 Single Channel Monitoring 171 Mass Memory USB Subsystem 34972A 174 USB Drive Front Panel 34972A 181 Remote Interface Configuration 34970A 183 Remote Interface Configuration 34972A 188 Calibration Overview 192 Factory Reset State 197 Instrument Preset State 198 Multiplexer Module Default Settings 199 Module Overview 200 34901A 20 Channel Multiplexer 201 34902A 16 Channel Multiplexer 203 34903A 20 Channel Actuator 205 34904A 4x8 Matrix Switch 207 34905A 6A Dual 4 Channel RF Multiplexers 209 34907A Multifunction Module 211 34908A 40 Channel Single Ended Multiplexer 213 18 Contents Chapter 5 Error Messages Execution Errors 219 Instrument Errors 224 Self Test Errors 235 Calibration Errors 236 Plug In Module Errors 239 Chapter 6 Application Programs Example Programs for Excel 7 0 248 Example Programs for C and C 250 Chapter 7 Tutorial System Cabling and Connections 257 M
180. he Utility Menu press e If you accidentally press G just press it again to turn off the SHIFT annunciator This chapter is divided into the following sections To Prepare the Instrument for Use on page 23 BenchLink Data Logger Software on page 25 To Connect Wiring to a Module on page 27 To Set the Time and Date on page 29 To Configure a Channel for Scanning on page 30 To Copy a Channel Configuration on page 32 To Close a Channel on page 33 Ifthe Instrument Does Not Turn On on page 34 To Adjust the Carrying Handle on page 36 To Rack Mount the Instrument on page 37 22 On Standby Switch WARNING Note that this switch is Standby only To disconnect the mains from the instrument remove the power cord Chapter 1 Quick Start To Prepare the Instrument for Use To Prepare the Instrument for Use 1 Check the list of supplied items Verify that you have received the following items with your instrument If anything is missing contact your nearest Keysight Technologies Sales Office or Keysight authorized reseller One power cord This User s Guide One Service Guide Certificate of Calibration if you ordered the internal DMM BenchLink Data Logger 3 Software on CD ROM To install the software see page 25 Quick Start Package if you ordered the internal DMM One RS 232 cable 34970A only One J type thermocouple and a flatblade screwdriver Any
181. he 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 You can configure the instrument to generate an alarm 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 For more information see Using Alarms With the Multifunction Module on page 148 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 A Factory Reset RST command Instrument Preset SYSTem PRESet command and Card Reset SYSTem CPON command reset the count to 0 154 Chapter 4 Features and Functions Totalizer Operations 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 m
182. hen 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 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 103 212 142 Chapter 4 Features and Functions Alarm Limits To set the upper and lower alarm limits on the specified 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 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 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
183. his 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 34970A 34972A makes measurements and what you can do to get the best results This chapter is divided into the following sections System Cabling and Connections on page 257 Measurement Fundamentals on page 265 Low Level Signal Multiplexing and Switching on page 300 Actuators and General Purpose Switching on page 306 Matrix Switching on page 310 RF Signal Multiplexing on page 312 Multifunction Module on page 314 Relay Life and Preventive Maintenance on page 321 256 WARNING Chapter 7 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 Signal Requirements such as voltage frequency accuracy and measurement speed Interconnection Requirements such as wire sizes cable lengths and cable routing Maintenance Requirements such as intermediate connectors cable terminations strain relief cable lengths and cable routing Cabl
184. ide 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 136 Chapter 4 Features and Functions Mx B Scaling 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 During a Monitor operation the gain and offset values are applied to all readings on the specified channel 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 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 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
185. ielded coaxial cable LHI pe TS S A PP A LO s a Center Conductor 7 n 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 260 Chapter 7 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 ION fr Modules A jf XA To Transducers f INNLIT JOAN S li i i y Np oo i 4 iy im eel f age
186. iguration on page 123 Voltage Measurement Configuration on page 130 Resistance Measurement Configuration on page 182 Current Measurement Configuration on page 133 Frequency Measurement Configuration on page 185 Mx B Scaling on page 136 Alarm Limits on page 189 Digital Input Operations on page 151 Totalizer Operations on page 153 Digital Output Operations on page 157 DAC Output Operations on page 159 System Related Operations on page 160 Single Channel Monitoring on page 171 Mass Memory USB Subsystem 34972A on page 174 USB Drive Front Panel 34972A on page 181 Remote Interface Configuration 34970A on page 183 Remote Interface Configuration 34972A on page 188 Calibration Overview on page 192 Factory Reset State on page 197 Instrument Preset State on page 198 Multiplexer Module Default Settings on page 199 Module Overview on page 200 34901A 20 Channel Multiplexer on page 201 34902A 16 Channel Multiplexer on page 208 34903A 20 Channel Actuator on page 205 34904A 4x8 Matrix Switch on page 207 34905A 6A Dual 4 Channel RF Multiplexers on page 209 34907A Multifunction Module on page 211 34908A 40 Channel Single Ended Multiplexer on page 213 88 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 in
187. information refer to Strain Gage Measurements on page 295 Note Keysight BenchLink Data Logger 3 software has built in strain gage measurement capability Use the following equations to calculate the gain and offset Where GF is the gage factor and Ryis the unstrained gage resistance For example a 350Q 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 6 digits of resolution for this measurement 137 Chapter 4 Features and Functions Mx B Scaling The maximum gain 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 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 Front Panel Operation The menu automatically guides you through the gain offset and measurement label settings SET GAIN SET OFFSET SET LABEL To reset 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
188. ing Measurement Rates to I O or internal 34970A 34972A memory into Memory to GPIB or to LAN USB RS232 or Memory ch sec ch sec ch sec Scanning DCV or Ohms channels 34901A 34908A 60 60 60 34902A 250 210 240 34902A into and out of memory using INIT FETCh 180 240 34902A with timestamp using MEAS 150 240 34902A with scaling and alarms 220 190 220 34902A DCV and ohms on alternate channels 80 80 80 Scanning ACV channels 2 34901A 34908A 50 50 50 34902A 100 90 100 Scanning Temperature Thermistor or T C channels 34901A 34908A 50 50 50 34902A 150 150 150 Scanning Digital In Totalizer channels 34907A Digital Input 275 250 275 34907A Totalizer 240 210 240 1 Speeds are for 4 digits delay 0 display off autozero off unless otherwise noted Use MEAS command for best I O performance RS232 at 115Kbaud 2 Maximum with default delays defeated 331 Chapter 8 Specifications System Speed Specifications System Speed Specifications Data out of memory 3 4 34970A 34972A FETCh of 50K readings over GPIB over RS232 over USB over LAN or memory readings sec readings sec readings sec readings sec Readings 800 600 55K 120K Readings with timestamp 450 320 35K 60K Readings with all format options ON 310 230 25K 50K 3 Assumes relative time format time since start of scan 4 Typical rates assuming lightly loaded PC and limited other traffic on I Os LAN ra
189. ing 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 12 110 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 34970A 34972A you can order it without the internal DMM In this configuration you can use the 34970A 34972A for signal routing or control applications If you install a multiplexer plug in module you can use the 34970A 34972A for scanning with an external instrument You can connect an external instrument such as a DMM to the multiplexer COM terminal i rc e External DMM Input a e fa si 2 eo Channels 5 peoooooolse N Maaa n ES Common Terminals ere COM H L 111 Chapter 4 Features and Functions Scanning with External Instruments To control scanning with an external instrument two control lines are provided When the 34970A 34972A and the external instrument are properly configured you can synchronize a scan sequence between the two GND 5 1 Channel Closed OUT ofo o 9 o g gt Ext Trig IN 6
190. ing when power is restored No error is generated 93 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 scan 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 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 To initiate a scan and store all readings in memory press the SCAN annunciator will turn on Each time
191. instrument automatically pairs channel n with channel n 10 84901A 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 TEMPERATURE RTD RTD 4W To select the nominal resistance R for the active channel choose the following item Ry 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 127 Chapter 4 Features and Functions Temperature Measurement Configuration Remote Interface Operation You can use the MEASure or CONF igure 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 For example the following statement configures channel 103 for 4 wire measurements of an RTD with a 0 00391 channel 103 is automatically paired with channel 113 for the 4 wire measurement SENS TEMP TRAN FRTID TYPE 91 103 The following state
192. 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 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 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 Front Panel Operation EVEN 7 BITS 185 Chapter 4 Features and Functions Remote Interface Configuration 34970A Flow Control Selection RS 232 You 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 Select one of the following None no flow control XON KOFF factory setting DTR DSR RTS CTS or Modem 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 XON XOFF This mode uses special characters embedded in the data stream to control the flow If the instrument is addressed to s
193. interval to 5 seconds TRIG COUNT 2 Sweep the scan list 2 times INIT Initiate the scan Note To stop a scan send the ABORt command 97 Chapter 4 Features and Functions Scanning Scan Once In this configuration the instrument waits for either a front panel key press or a remote interface command before sweeping through the scan list 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 You can specify a scan count which sets the number of front panel key presses or scan trigger commands that will be accepted before terminating the scan See Scan Count on page 102 for more information Mx B scaling and alarm limits are applied to measurements during a Scan Once operation and all data is stored in non volatile memory Front Panel Operation MANUAL SCAN To initiate the scan and store all readings in memory press The ONCE annunciator turns on as a reminder that a Scan Once operation is in progress Note To stop a scan press and hold 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 GPIB interf
194. ion capacitance Zi Parallel impedance of R Ci Vex RS goes R PZ Error VL 277 Chapter 7 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 HI DMM LOO ji Injected Current 50 60 Hz ac line leakage current With Connection A see below the injected 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 nn eaaa R R Vs DMM Vs Fx l DMM eee A Se LO l NG gt LOS A 77 eT We i Co SP 7 tf Connection A Connection B 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 120 for a discussion of integration time 278 Chapter 7 Tutorial Measurement Fundam
195. ith external instrument 111 with Monitor function 91 with Mx B scaling 91 with totalizer channels 92 SCPI language syntax conventions 89 vision query 173 screw terminal connections ac current 28 ac voltage 28 de current 28 dc voltage 28 frequency 28 period 28 resistance 28 RTDs 28 thermistors 28 thermocouples 28 wiring strain relief 27 wiring strip length 27 screw terminal diagram 34901A 201 34902A 203 34903A 205 34904A 207 34905A 209 34906A 209 34907A 211 34908A 213 secure calibration 193 security code calibration factory setting 191 to change 193 self test complete 24 failure 24 power on 24 sense connections RTD 127 sense connections 300 sensor types 68 serial RS 232 interface baud rate 184 cable 23 61 connector location 9 flow mode 185 parity 184 selecting interface 183 settling delay automatic 106 default value 105 defined 105 settings 105 settling time 292 settling time ac voltage 281 shearing strain 293 shielding 258 shielding thermocouple wire 273 SHIFT annunciator 8 22 Shift key 22 shunt impedance 273 signal conditioning 76 ac voltage 279 de voltage 274 simplified schematic 34901A 200 34902A 202 34903A 204 34904A 206 34905A 208 34906A 208 34907A 210 34908A 212 single channel Monitor 171 172 sink current digital output 313 sliding shelf kit rack mounting 38 slope
196. itor multiple instruments and measurement points while performing other PC based tasks The Computer and Interface Cable 34970A only Computers and operating systems are not discussed in this chapter In addition to the computer and operating system you will need a serial port RS 232 or GPIB port IEEE 488 and an interface cable Serial Often built into the computer no additional hardware is required RS 232 Cable length is limited to 45 ft 15 m GPIB IEEE 488 Speed faster data and command transfers Cable length is limited to 60 ft 20m Drivers usually included in the operating system Only one instrument or device can be connected per serial port Additional system flexibility multiple instruments can be connected to the same GPIB port Requires an expansion slot plug in card in PC and associated drivers Cables readily available and inexpensive The 34970A is shipped with a serial cable if internal DMM is ordered Cabling is susceptible to noise causing slow or lost communications Varying connector ys and styles Direct Memory Transfers are possible Requires special cable Data transfers up to 85 000 characters sec Data transfers up to 750 000 characters sec You can overcome these cable length limitation using special communications hardware For example you can use the Keysight E5810A LAN to GPIB Gateway interface or a serial
197. ives information on configuring the 34970A for remote interface communication For more information on configuring the instrument from the front panel see To Configure the Remote Interface starting on page 53 For more information on the SCPI commands available to program the instrument over the remote interface see the Keysight 84970A 34972A Programmer s Reference Help GPIB Address Each device on the GPIB 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 GPIB address is displayed at power on You can set the GPIB address from the front panel only 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 Your computer s GPIB interface card has its own address Be sure to avoid using the computer s address for any instrument on the interface bus Keysight s GPIB interface cards generally use address 9 1 Front Panel Operation ADDRESS 09 183 Chapter 4 Features and Functions Remote Interface Configuration 34970A Remote Interface Selection The 34970A is shipped with both an GPIB IEEE 488 interface and an RS 282 interface Only one interface can be enabled at a time The GPIB interface is selected when the instrumen
198. ize ground loop errors If Verouna is a DC voltage keep Ry small compared to Rj IfVeroung is an AC voltage keep Ry small compared to Z and set the DMW s integration time to 1 PLC or greater see page 120 for a discussion of integration time 263 Chapter 7 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 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 Vol
199. k 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 al 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 PM Set the date Use C and D to select the field to modify and turn the knob to change the value JUN 01 2009 29 Measure 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 slot number 100 200 or 300 and the two digits on the right indicate the channel number 102 110 etc Note You can use A and D to skip to the beginning of the previous or next slot For this example assume that you have the 3490
200. k low not responding Module reported command syntax error Module reported nonvolatile memory fault Module reported temperature sensor fault Module reported firmware defect Module reported incorrect firmware installed 239 Chapter 5 Error Messages Plug In Module Errors 240 Application Programs Application Programs This chapter contains several example programs to help you develop programs for your specific measurement application See the Keysight 34970A 34972A Programmer s Reference Help for details on the SCPI language for the instrument The examples in this chapter have been tested on a PC running on Windows 95 The examples are written for use over the GPIB interface and require a VISA Virtual Instrument Software Architecture library for use with your GPIB 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 These programs were written for the 34970A but other than the connectivity the principles and code should generally apply to the 34972A as well For programs specific to the 34972A see the product page at www keysight com find 34972A Note The GPIB IEEE 488 address is set to 09 when the instrument is shipped from the factory The examples in this chapter assume an GPIB address of 09 242 Chapter 6 Application Programs Example Programs for Excel 7 0 Example P
201. l reset both DACs to 0 VDC Note 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 5 305 159 Chapter 4 Features and Functions System Related Operations System Related Operations This section gives information on system related topics such as storing 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 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
202. l see new choices CAL SECURED and UNSECURE CAL 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 Tochange 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 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 panel also changes the code as seen from the remote interface 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 22007943 Enter new code 194 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 name and phone number of the person to contact for
203. lizer 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 257 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 FV Switch Noise caused by bounce Closed creates a false count Nin Limit Switch Totalizer 318 Chapter 7 Tutorial Multifunction Module Voltage DAC Output The 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 used as a programmable voltage source for analog input to other devices 16 Bit me ae aes Output Voltage Digital Data V gt PD RL 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 supplying 10 mA maximum current Note You must limit the output current to 40 mA total for all three slots six DAC channels To maintain the rated output accuracy the load Ry in the diagram shown above must be greater than 1 kQ 319 Chapter 7 Tutorial Multifunction Module DAC Errors The output of a DAC varies with
204. ll through the error numbers Press D 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 218 101 102 103 105 108 109 112 113 Chapter 5 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 orCONF 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 allowed within a command string Parameter not allowed More parameters were receive
205. llowing statement configures 203 for a J type thermocouple measurement SENS T EMP TRAN TC TYPE J 203 The following statements use the SENSe command to set a fixed referenc channel e junction temperature of 40 degrees always in C on 203 SENS T EMP TRAN TC RJUN TYPE FIXED 203 SENS T EMP TRAN TC RJUN 40 203 The following statement enables the thermocouple check feature on the specified channels opens are reported as 9 90000000E 37 SENS T EMP TRAN TC CHECK ON 203 301 126 Chapter 4 Features and Functions Temperature Measurement Configuration RTD Measurements To connect an RTD to the module s screw terminals see page 28 The instrument supports RTDs with a 0 00385 DIN IEC 751 using ITS 90 software conversions or a 0 00391 using IPTS 68 software conversions The default is a 0 00385 The resistance of an RTD is nominal at 0 C and is referred to as Ro The instrument can measure RTDs with R values from 49Q to 2 1 KQ The default is R 1000 PT100 is a special label that is sometimes used to refer to an RTD with a 0 00385 and R 100 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
206. ls 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 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 34901A module Or you may have tried to configure scaling on a module that does not connect to the internal DMM 227 306 307 308 309 Chapter 5 Error Messages Instrument Errors 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 ch
207. lue MCV 40 Year EPUP This text indicates that the instrument is an Industrial Scientific and Medical Group 1 Class A product CISPER 11 Clause 4 This text indicates product compliance with the Canadian Interference Causing Equipment Standard ICES 001 Note Unless otherwise indicated this manual applies to all serial numbers The Keysight Technologies 34970A 34972A 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 BenchLink Data Logger 3 Software for Microsoft Windows included Flexible Data Acquisition Switching Features e 6
208. m the instrument or For information on controlling a scan with an external instrument refer to Scanning With External Instruments on page 111 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 PRESet command does not affect the internal DMM configuration Front Panel Operation DMM ENABLED DMM DISABLED Remote Interface Operation INSTrument DMM OFF ON Firmware Revision Query The instrument has three microprocessors for control of various internal 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 For each plug in module the instrument returns one revision number for the on board processor 167 Chapter 4 Features and Functions System Related Operations Front Panel Operation REV X X Y Y Z 2Z for 34970A REV X XX Y YY Z for 34972A Turn the knob to read the firmware revision number for the module installed in each of the three slots If a slot does n
209. m 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 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 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 Ifyou plan to use alarms on a channel which will also use scaling 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 Ifyou 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
210. med as follows dat HHft csv If you use the command MMEMory FORMat READing RLIMit OFF all of the data will be stored in one file named dat00001 csv You can issue the command MMEMory FORMat READing RLIMit ON to limit the data to 64K 1 65 535 sweeps per file in which case the sweeps are stored in multiple files named dat00001 csv dat00002 csv dat00003 csv and so on This is helpful for importing data into spreadsheet or other data analysis software Note that some spreadsheet or data analysis software may import the data more easily if you change the extension from esv to txt If your software does not import the file correctly try changing the extension on the data file 178 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A Contents of Data Files Logging into data files is only supported for channels that are in the scan list The possible channels are shown in the table below note that s stands for the slot number which is 1 2 or 3 For example the 34901A module supports could have channels 101 120 201 220 or 301 320 Module Description Channels 34901A 20 channel 2 wire armature multiplexer s01 s20 34902A 16 channel 2 wire reed multiplexer s01 s16 34907A 2 channel DIO input s01 s02 34907A 1 channel totalizer s03 34908A 40 channel 1 wire armature multiplexer s01 s40 The format for all USB data files is similar to what Key
211. ment 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 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 bl
212. ment sets the nominal resistance Ro to 10009 on channel 1083 SENS TEMP TRAN FRTID RES 1000 103 128 Chapter 4 Features and Functions Temperature Measurement Configuration Thermistor Measurements To connect a thermistor to the module s screw terminals see page 28 The instrument supports 2 2 KQ 44004 5 KQ 44007 and 10 KQ 44006 thermistors Front Panel Operation To select the thermistor function for the active channel choose the following items TEMPERATURE 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 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 103 129 Chapter 4 Features and Functions Voltage Measurement Configuration Voltage Measurement Configuration To connect voltage sources to the module s screw terminals see page 28 This section contains information to help you configure the
213. ments 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 measurement 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 288 Chapter 7 Tutorial Measurement Fundamentals Current Measurements Current measurements are allowed only on the 84901A 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 c
214. mocouple types and some key characteristics of each Note The thermocouple conversion routines used by the 34970A 34972A are compatible with the International Temperature Scale of 1990 ITS 90 272 Thermocouple Types Chapter 7 Tutorial Measurement Fundamentals T C Type Pos Lead Neg Lead BH san AE ah 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 DIN Red Gray in 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 recommended 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 R
215. mote Interface 34972A on page 55 To Store the Instrument State on page 57 40 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 contains examples of using the front panel menus Configure the measurement parameters on the displayed channel Select the measurement function dc volts ohms etc on the displayed channel Select transducer type for temperature measurements Select units C F or K for temperature measurements Select measurement range or autorange Select measurement resolution Copy and paste measurement configuration to other channels Configure the scaling parameters for the displayed channel Set the gain M and offset B value for the displayed channel e Make a null measurement and store it as the offset value Specify a custom label RPM PSI etc for the displayed channel Configure alarms on the displayed channel 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 that will generate an alarm digital input only Configure the four Alarm Output hardware lines
216. mple 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 Suffix not allowed A parameter suffix was specified when one was not allowed 220 148 151 158 168 178 211 213 Chapter 5 Error Messages Execution Errors 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
217. mple of a contact closure detection channel is shown below 5 V 10 kQ I O Line 1 of 8 X TTL Reference 621v X Limit Switch Yy Digital Read 314 Chapter 7 Tutorial Multifunction Module Digital Output The 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 Po as 5 V External Circuit lw 10 kQ laD a i Output ma s gt l i I O Line 1 of 16 7 i E 0 20 J Each output 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 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 20 For non TTL logic you must provide an external pull up A description of the pull up calculation is given on the following page Ifused with an external power supply and pull up the external supply must be greater than 5 VDC and less than 42 VDC 315 Chapter 7 Tutorial Multifunction Module Using an External Pull Up In general an external pull up is require
218. n 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 If you enter the wrong secure code NO MATCH is displayed and a new choice EXIT is shown Remote Interface Operation To unsecure the instrument send the following command with the correct security code CAL SECURE STATE OFF HP034970 193 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 or AT034972 depending on the product number 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 Front Panel Operation 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 press again When you return to the menu you wil
219. n be used The table below lists typical cable specifications Cable Type Nominal Impedance Capacitance Attenuation Twisted Pair 100Q at 1 MHz 10 to 20 pF ft Up to 1 dB 100 ft at 1 MHz Shielded Twisted Pair 100Q at 1 MHz 10 to 20 pF ft Up to 1 dB 100 ft at 1 MHz Coaxial 50Q or 75Q at 100 MHz 15 to 25 pF ft Up to 6 dB 100 ft at 100 MHz Twisted Pair Ribbon 100Q at 1 MHz 15 to 20 pF ft Up to 1 dB 100 ft at 1 MHz 258 Chapter 7 Tutorial System Cabling and Connections Grounding Techniques One purpose 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 MH
220. n channel numbering and layout refer to Module Overview starting on page 200 You can also query the state of the three relays on the internal DMM These relays are numbered 1 2 and 3 which correspond to relays K102 K103 and K104 respectively These relays open or close when a function or range is changed on a module The 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 channels 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 08 and 23 etc Therefore when you query the relay count on a channel the number reflects the number of times that the relay was closed For example the relay count will always be the same on channels 01 and 21 You can reset the count allowed only from remote but the instrument must be unsecured see Calibration Overview on page 192 to unsecure the instrument For more information on relay life and load considerations refer to Relay Life and Preventive Maintenance starting on page 321 169 Chapter 4 Features and Functions System Related Operations 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 i
221. n 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 169 Switching Topologies Several switching plug in modules are available with different topologies for various applications The following switching topologies are available e Multiplexer 84901A 34902A 34905A 34906A 34908A Matrix 84904A Form C Single Pole Double Throw 34903A The following sections describe each of these switching topologies 70 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 77 Channel 1 Common sy CO Channel 2 lt Channel 3 Channel 4 Multiplexers are available in several types One Wire Single Ended Multiplexers for common LO measurements For more information see page 301 Two Wire Multiplexers for floating measurements For more information see page 301 Four Wire Multiplexers for resistance and RTD measurements For more information see page 802 Very High Frequency VHF Multiplexers for switching frequencies up to 2 8 GHz For more information see page 312
222. n 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 Global 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 OE TTT TT Te Ue UY EY eT ey YT OY vee Oe Oe OY OY OO Oe OY OY Oe OY Oe OY OY Oe OY WYO YOY OY OY OY Oe Ov OY Oe Ovo Oe oe vee This routine requires the file VISA32 DLL which typically resides in the c windows system directory on your PC This routine uses the VTL Library to send commands to the instrument A description of these and additional VTL commands can be found in the Keysight VISA User s Guide A cn he eh Public Sub SendSCPI SCPICmd As String This routine sends a SCPI command string to the GPIB 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
223. nal impedance 255 resistance 256 RS 232 23 61 shielded coaxial 258 shielding 258 specifications 255 twisted pair 67 258 types 67 wire gauge size 256 CALC AVER command 110 calculation error thermocouple 273 calendar factory setting 166 setting 29 166 calibration overview 191 read count 195 security code 191 text message 194 to secure 193 to unsecure 192 calibration certificate 23 capacitance cable 256 capacitive coupling 258 301 Card Reset key 33 carrying handle adjusting 36 removing 36 celsius setting units 123 Channel Advance external scan ning connector 9 10 operation 112 Channel Closed external scan ning connector 9 10 operation 112 channel configuration copying 32 front panel 30 channel delay automatic 106 default values 105 defined 105 settings 105 channel list building from front panel 94 building from remote 95 examples 89 rules 89 channel number with readings 104 channel numbering 30 34901A 200 34902A 202 34903A 204 34904A 206 34905A 208 34906A 208 34907A 210 34908A 212 chassis ground 9 10 clearing reading memory 91 clock factory setting 166 setting the 29 166 Close key 33 coaxial cables 67 258 coefficient temperature 286 color codes thermocouples 271 command syntax SCPI conventions 89 version query 173 common LO multiplexers 71 298 common mode noise 273 CONFIG annunciator 8 CONFigure
224. nd An Instrument Preset SYSTem PRESet command or Card Reset SYSTem CPON command does not change the setting 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 sean OCOMP ON Remote Interface Operation RES OCOM ON 208 Enable offset compensation 2 wire FRES OCOM ON 208 Enable offset compensation 4 wire For 4 wire measurements specify the paired channel in the lower bank source as the lt ch_list gt parameter 132 Chapter 4 Features and Functions Current Measurement Configuration Current Measurement Configuration To connect a current source to the module s screw terminals see page 28 This section contains information to help you configure the instrument for making current measurements on the 34901A multiplexer module This module has two fused channels for direct DC and AC current measurements on the measurement ranges shown below 10 mA 100 mA 1A Autorange Note Current measurements are allowed only on channels 21 and 22 on the 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 Ap
225. nded replacement during yearly calibration Readings 50 000 internal readings with timestamp readable during scan Time Stamp Resolution Relative 1 ms Absolute 1s States 5 instrument states Alarm Queue Up to 20 events USB Drive FAT or FAT32 format General Specifications Power Supply 100 V 120 V 220 V 240 V 10 Power Line Frequency Power Consumption Operating Environment Storage Environment Weight Mainframe Safety RFI and ESD Warranty 45 Hz to 60 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 Net 3 6 kg 8 0 Ibs Conforms to CSA US 1244 IEC 1010 CAT CISPR 11 IEC 801 2 3 4 1 year 1 Storage at temperatures above 40 C will decrease battery life This ISM device complies with Canadian ICES 001 Cet appareil ISM est conforme a norme NMB 001 du Canada 330 Chapter 8 Specifications System Speed Specifications 1 Mi System Speed Specifications 1 Single Channel Reading Rates to I O or internal 34970A 34972A memory into Memory to GPIB or to LAN USB RS232 or Memory readings sec readings sec readings sec Single Channel ASCII dcV readings 500 440 500 Single Channel while changing scale eg MEAS dcV 25 25 25 10 MEAS dcV 1 Single Channel while changing function eg MEAS 12 12 12 dcV MEAS Ohms Scann
226. nel 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 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 To stop a Monitor press again Note that while the instrument is 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 To read the monitor data from the selected channel send the following command This command returns the reading only the units time channel and alarm information are not returned the FORMat READing commands do not apply to monitor readings ROUT MON DATA 172 Chapter 4 Features and Functions Single Channel Monitoring 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 wit
227. ngs 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 Front Panel Operation To configure an alarm on a digital input channel choose from the following 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 00X10010 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 HI ALARM ONLY 148 Chapter 4 Features and Functions Alarm Limits 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
228. nitor 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 Readings acquired during a Monitor are not stored in memory but they are displayed on the front panel however all readings from a scan in progress at the same time are stored in memory 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 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 You can monitor a multiplexer channel only if the internal DMM is installed and enabled see Internal DMM Disable on page 167 The channel must also be configured to be part of the scan list 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 required either The count on a totalizer channel is not reset when it is being monitored the Monitor ignores the totalizer reset mode 171 Chapter 4 Features and Functions Single Channel Monitoring In the Alarm Scan configuration see Scanning on Alarm on page 100 the instrument sweeps the scan list once each time a reading crosses an alarm limit on a chan
229. nly 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 columnIndex 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 columnIndex 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 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 1 6 ConvertTime dateNumber timeNumber End Function Sub GetErrors Call this routine to check for instrument errors The GPIB 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 249 Cha
230. nput 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 5 VDC 100 uV Range Error 0 0005 x 10 VDC 50 uV Total Error 100 uV 50 uV 156 uV 0 0030 pf 5 VDC 30 ppm of 5 VDC 339 Chapter 8 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 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 6 digit measurement with 20 overrange capability Sensitivity Sensitivity is the minimum level that the internal DMM can det
231. nput e Signal Signal OH Conditioning Pi gt Analog to Digital Converter Main 1 Processor I 1 _ To From g Earth A Referenced Section Optical Isolators 75 Chapter 3 System Overview Measurement Input Signal Conditioning Ranging and Amplification Analog input signals are multiplexed into the internal DMM s signal conditioning 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 DC 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 DC 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 selects the range to use for each measurement based on the input signal For fastest scanning operation
232. ns 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 measurement Not able to execute command in local mode The instrument has received a READ or MEASure command while in the local mode 234 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 Chapter 5 Error Messages Self Test Errors Self Test Errors The following errors indicate failures that may occur during a self test Refer to the 84970A 34972A Service Guide 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
233. nternal 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 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 305 399 170 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 troubleshooting 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 The Mo
234. nts 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 number 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 Cells I 3 1 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 GPIB End Sub 244 Chapter 6 Application Programs Example Programs for Excel 7 0 l 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 Functio
235. o TEINA Qik J Sh Ee jok 9 28 Q zZ p in z F gt a I S T gt P4 m H o rm e L 9 2 i 9 9 z si oks amp m S m Eg J va fs 214 Chapter 4 Features and Functions 34908A 40 Channel Single Ended Multiplexer 215 Chapter 4 Features and Functions 34908A 40 Channel Single Ended Multiplexer 216 Error Messages Error Messages 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 If more than 10 errors 34970A or 20 errors 84972A 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 annunciator is on press to view the errors Use the knob to scro
236. o multiple test points as shown below Multiplexer OUT COM H 2 7 8 8 2 Channel 1 A L i GND COML e o 2 Channel 2 4 Channel 3 f 2 Channel 4 F 303 Chapter 7 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 generated 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 259 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 C 4 e Cag so ad Source NS ANS Source Cow A Source Source DMM 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 ea
237. o 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 262 Chapter 7 Tutorial System Cabling and Connections Noise Caused by Ground Loops When measuring voltages in circuits where the internal DMM and the device under test are both referenced to acommon 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 V which is added to the measured voltage RL i s Hng a Viest DMM RL LO z Ci I 250 pF iy E I I Rj V ground i 710 eR i 1 N a K EER E E wade 29 af Where R Lead resistance R DMM isolation resistance C DMM isolation capacitance Vground Ground noise voltage V Current flow caused by Vground ae L bee Zx Zei C 10 MQ at 50 or 60 Hz VL Ix RL To minim
238. o metal contact thermocouple effect or electrochemical batteries for a description of the thermocouple effect see page 262 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 DC voltage measurement The second measurement is subtracted from the first prior to scaling the result thus giving a more accurate resistance measurement Refer to Offset Compensation on page 132 for more information Offset compensation can be used for 2 wire or 4 wire ohms measurements but not for RTD or thermistor measurements The 34970A 34972A 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 increas
239. ocking 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 DC 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 283 Chapter 7 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
240. ode 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 arcea COUNT FALLING COUNT RISING To add a totalizer read to a scan list choose the following item EAD 155 Chapter 4 Features and Functions Totalizer Operations Remote Interface Operation To read the count from the specified totalizer channel send the following command The count may be returned with time stamp channel number and alarm status information depending on the FORMat READing command setting see Reading Format on page 104 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 To immediately clear the count on the specified totalizer channel whether scanning or not send the following command wn ENSe TOTalize CLEar IMMediate lt ch_list gt 156 Chapter 4 Features and Functions Digital Output Operations
241. 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 8 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 Errorging Errorcrest factor ErrOrpandwidth Where Errorgine DMM s sinewave accuracy see Chapter 8 Specifications Errorcrest factor DMM s crest factor see Chapter 8 Specifications Errorpandwidth Estimated bandwidth error as shown below 2 C F x F Errotbandwidth 47 BY x BW Where C F Signal crest factor see the table on page 282 F Fundamental input signal frequency BW DMM s 3 dB bandwidth 1 MHz for the 34970A 34972A 284 Chapter 7 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 8 Error sine 0 05 0 04 0 09 ErrOrerest factor 0 15 2 Error
242. 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 291 Chapter 7 Tutorial Measurement Fundamentals The 4 wire ohms 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 R meter lt test lt LO Sense LO Source 292 Chapter 7 Tutorial Measurement Fundamentals Offset Compensation Most connections in a system use materials that produce small DC voltages due to dissimilar metal t
243. om 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 16 bit word only if neither port is in the scan list 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 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 and a high signal 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 Move the jumper to the TTL position factory setting to detect changes through TTL threshold levels Analog Output DAC The two 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 output current to 40 mA total for all three slots six DAC channels 211 Chapter 4 Features and Functions 34907A Multifunction Module WIRING LOG Slot Number 0100 0200 0300 Comments 01 DIO 1 ie Threshold Jumper aps
244. om the most recent scan 77 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 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 the scan list Scan Count 1 to 50 000 scans or continuous Scan List 1 sweep Scan to Scan interval 0 to 99 59 59 hours e You can manually control a scan by repeatedly pressing from the front panel 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 78 Chapter 3 System Overview Measurement Input Scanning with External Instruments If your application doesn t require the built in measurement capabilities of the 34970A 34972A you can order it without the internal DMM In this configuration you can use the 34970A 34972A for signal routing or control applications If you install a multiplexer plug in module you can use the 34970A 34972A for scanning with an external instrument You can connect an external instrument such as a DMM to the multiplexer COM terminal H G LS H S e L S e Input k Channels H S LQ
245. on For frequency and period measurements the range parameter is used to compute a specific measurement resolution see the Keysight 84970A 34972A Programmer s Reference Help for details When specifying a non default resolution both the range and resolution parameters must be specified within the MEASure and CONFigure commands Refer to the Keysight 34970A 384972A Programmer s Reference Help for more information e The MEASure and CONFigure commands contain an optional range parameter which allows you to specify the range or autoranging The instrument 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 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 RANGI 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 El CONF VOLT DC 10 DEF 301 116 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 f
246. on of the software in this product is licensed under terms of the General Public License Version 2 GPLv2 The text of the license and source code can be found at www keysight com find GPLV2 This product utilizes Microsoft Windows CE Keysight highly recommends that all Windows based computers connected to Windows CE instruments utilize current anti virus software For more information go to the product page at www keysight com find 34970A www keysight com find 34972A Declaration of Conformity Declarations of Conformity for this product and for other Keysight products may be downloaded from the Web Go to http regulations products keysight com and click on Declarations of Conformity You can then search by product number to find the latest Decla ration of Conformity Warranty The material contained in this document is provided as is and is subject to being changed with out notice in future editions Further to the maximum extent permitted by applicable law Keysight disclaims all warranties either express or implied with regard to this manual and any information contained herein including but not limited to the implied warranties of merchant ability and fitness for a particular purpose Keysight shall not be liable for errors or for incidental or consequential damages in con nection with the furnishing use or performance of this document or of any information contained herein Should Keysigh
247. ot 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 Keysight Technologies 34972A 0 1 II O 0O FP FPGA See the Keysight 34970A 34972A Programmer s Reference Help for details 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 100 200 300 This command returns a string in the form HEWLETT PACKARD 34901A 0 X X for 34970A Keysight Technologies 0 0 0 for 34970A See the Keysight 34970A 34972A Programmer s Reference Help for details 168 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 counts 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 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 o
248. otalizer 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 148 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 that channel s alarm status is stored in reading memory as the readings are taken Each reading 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 Reading memory is not cleared when you read it 2 As alarm events are generated they are also logged in an alarm queue 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 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 139 Chapter 4 Features and Functions Alarm Limits You can assign an alar
249. ource and sense connections Front Panel Operation To select the channel advance source choose from the following items AUTO ADVANCE EXT ADVANCE To initiate the scan press the SCAN annunciator will turn on To configure the instrument for 4 wire external scanning choose the following item 4W SCAN 113 Chapter 4 Features and Functions Scanning with External Instruments 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 114 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 befo
250. output readings lost in USB transfer Internal error USB write operation was unable to keep up with data collection Reading memory export aborted due to measurement reconfig The export of reading memory was aborted because of measurement reconfiguration Not able to execute while logging data to USB Operation can not be completed while data is being actively logged to USB Not able to execute while copying data to USB Operation can not be completed while data is being exported to USB Not able to execute while importing a configuration from USB Operation can not be completed while a measurement configuration is being imported from USB Logging request ignored USB device is busy Logging was not started because USB is busy but the scan will continue to run normally placing data in reading memory External USB drive is inaccessible External USB drive can not be accessed either the disk is full or else it may need to be reformatted The instrument will behave as if no drive is present The instrument was unable to find a valid partition to use for storing instrument data 231 459 460 461 462 463 464 465 466 467 468 469 Chapter 5 Error Messages Instrument Errors Logging to USB was stopped Data logging was stopped prior to completion due to an abort or some other error condition Logging to USB was stopped after 2 32 sweeps of data Instrument is only able to capture 2 32 4 3 billion sw
251. p channel number and alarm status information From 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 104 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 The MEASure 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 stores readings in memory Use the FETCh command to retrieve stored readings from memory the readings are not erased when you read them 108 Chapter 4 Features and Functions Scanning 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 C and E 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 Jana Select Channel L
252. page 171 This feature is useful for troubleshooting your system before a test or for watching an important signal If you 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 cleared from memory When you add a multiplexer channel to a scan list that entire module is dedicated to the scan The instrument 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 91 Chapter 4 Features and Functions Scanning While a 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 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
253. peration DEF GATEWAY Setting the DNS Server You can set the address of the DNS server for your LAN connection Contact your network administrator to determine whether DNS is being used and for the correct address If DHCP is available and enabled DHCP will auto assign the DNS address This auto assigned DNS address takes precedence over the static DNS address assigned with this menu option You must disable DHCP in order to set this on the front panel Front Panel Operation DNS SERVER Viewing the MAC Address You can view the MAC address of your 34972A This address is of the form HEHHEHEHH HH HH where each is a hexadecimal digit 0 9 or A F The LAN relies on every device attached to the network having a unique MAC address The MAC address for each instrument is set at the factory and cannot be changed Front Panel Operation MAC ADDRESS 191 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 34970A 34972A Service Guide Calibration Security This feature allows you to enter 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 mu
254. plies 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 20Hz to 300 KHz Medium 1 second reading 0 2 seconds 200 Hz to 300 kHz Fast 0 12 seconds reading 0 02 seconds The instrument 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 133 Chapter 4 Features and Functions Current Measurement Configuration 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 8 Hz medium filter 20 Hz or fast filter 200 Hz for the active channel The default is the medium filter Advanced TF 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 VOLT AC BAND 3 203 Select the slow filter 8 Hz 134 Chapter 4 Features and Functions Frequency Measurement Configuration Frequency Measurement Configuration To connect an AC source to the module s screw
255. ps and advanced measurement configurations CHANGE SAVED 57 Chapter 2 Front Panel Overview To Store the Instrument State 58 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 Data Acquisition System Overview see below Signal Routing and Switching on page 70 Measurement Input on page 74 Control Output on page 83 Data Acquisition System Overview You can use the Keysight 34970A 34972A 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 34970A 34972A Modules Cabling and Events 60 Chapter 3 System Overview Data Acquisition System Overview The configuration on the previous page offers the following advantages You can use the 34970A 34972A 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 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 You can use a single PC to mon
256. pter 6 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 Keysight 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 Keysight 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 Be sure to have access in the project to visa lib or visa32 lib usually found in the c vxipnp or c visa directory 250 Chapter 6 Application Programs Example Programs for C and C l C C Example dac_out c dac_out c RK KK k e RA RR A RR k k IR k e A k AR RA RR RAIA RR AR IRA k k AR k k k k k k k k k k k k k k Required 34907A Multifunction Module in slot 200 VISA library K This program uses the VISA library to communicate with the 34970A The program queries slot 200 and displays the response It then resets is the instrument and sends the value voltage to the DAC on channel 205 td FER AR AA RAR I A IR IRR AR ARR RA AIA ARR A A k k RIAA k k k k k k k k k k k k k k k I
257. r 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 84970A or 20 errors 84972A 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 Ifmore than 10 errors 34970A or 20 errors 34972A 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 annunciator is on press to view the error Use the knob to scroll through the error numbers Press D to view the text of the error messa
258. rage 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 CEJ C RMS gt DC RMS Responding Error o 1 414 E aaa calibrated for O error The internal DMM s AC voltage and AC current functions measure the ac coupled true RMS value This is in contrast to the actdc 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 equal 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 DC 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 Jac Dc 282 Chapter 7 Tutorial Measure
259. rain 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 changes but rejecting strain changes Subtracting measurements from the second gage will remove any undesirable strain errors 297 Chapter 7 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 Analog Signal lt Input Conditioning FF gt lt Counter Latch J f py i a of S 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
260. rated 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 command 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 150 Chapter 4 Features and Functions Digital Input Operations Digital Input Operations The multifunction module 84907A 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 148 When you add a digital read
261. ration TRIG COUNT 20 Note To configure a continuous scan send TRIG COUNT INFINITY 103 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 From 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 per channel basis 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 The MEASure and CONFigure commands automatically turn off the units time channel and alarm information A Factory Reset RST command turns off the units time channel and alarm information 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 R R FORMat READing TIME TYPE ABSol
262. ration TST Returns 0 if the self test is successful or 1 if it fails 164 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 From the remote interface you can also display a 13 character message on the front display You can only disable the front panel display by sending a command from the remote interface you cannot disable the front panel while in local operation When disabled the entire front panel display goes blank 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 i 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 You can use letters A Z numbers 0 9 and special characters like 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
263. re 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 instrument 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 Autorange thresholds Down range at lt 10 of range Up range at gt 120 of range Ifthe input 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 For a complete list of the measurement ranges available for each function refer to the instrument specifications in chapter 8 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 115 Chapter 4 Features and Functions General Measurement Configurati
264. ready configured any multiplexer channels for scanning you cannot independently close and open individual relays on that module 1 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 Open 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 Open write ean en 34901A 20 Channel Mux e e e 34902A 16 Channel Mux e e e 34908A 40 Channel Single Ended Mux m e e e 34903A 20 Channel Actuator e e 34904A 4x8 Matrix e e 34905A Dual 4 Channel RF Mux 509 e 34906A Dual 4 Channel RF Mux 75Q e 34907A Multifunction Module DIO e 34907A Multifunction Module Totalizer e 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 33 N i Chapter 1 Quick Start If the Instrument Does Not Turn On If the Instrument 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 384970A 34972A Service Guide for instructions on returning the instrument to
265. relative humidity of 20 to 80 at 40 C or less non condens ing This instrument or system is designed to operate at altitudes up to 2000 meters and at temperatures between 0 C and 55 C Technical Support If you have questions about your shipment or if you need information about warranty service or technical support contact Keysight Technologies In the United States 800 829 4444 In Europe 31 20 547 2111 In Japan 0120 421 345 Or go to www keysight com find assist for information on contacting Keysight in your country of specific location You can also contact your Keysight Technologies Representative Safety Symbols NY a JN AX CAT I CE Ge N10149 fa 1SM1 ICES NMB 001 Alternating current Frame or chassis terminal Standby supply Unit is not completely disconnected from AC mains when switch is off Caution risk of electric shock Caution refer to accompanying documents Earth ground terminal IEC Measurement The CE mark is a registered trademark of the European The CSA mark is a registered trademark of the CSA International The C tick mark is a registered trademark of the Spectrum Management Agency of Australia This signifies compliance with the Australian EMC Framework regulations under the terms of the Radio Communications Contains one or more of the 6 hazardous substances above the maximum concentration va
266. rements 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 Wire Ohms 2 or 4 Wire Ohms Transducer Sensitivity 6 uV C to 60 uV C Rg x 0 004 C z 4000 C Probe Accuracy 0 5 C to 5 C 0 01 C to 0 1 C 0 1 C to 1 C Cost U S Dollars 1 foot 20 to 100 each 10 to 100 each Durability Rugged Fragile Fragile 267 Chapter 7 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 34970A 34972A supports RTDs with a 0 00385 DIN IEC 751 using ITS 90 software conversions and a 0 00391 using IPTS 68 softw
267. rmed or adhered to could result in damage to the product or loss of important data Do not proceed beyond a CAUTION notice until the indicated condi tions are fully understood and met A WARNING notice denotes a hazard It calls attention to an operating procedure prac tice or the like that if not cor rectly performed or adhered to could result in personal injury or death Do not pro ceed beyond a WARNING notice until the indicated con ditions are fully understood and met Additional Safety Notices The following general safety precau tions must be observed during all phases of operation of this instrument Failure to comply with these precau tions or with specific warnings or instructions elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Keysight Technologies assumes no liability of the customer s failure to comply with the require ments General Do not use this product in any manner not specified by the manufacturer The protective features of this product may be impaired if it is used in a manner not specified in the operation instructions Before Applying Power Verify that all safety precautions are taken Make all connections to the unit before applying power and select the appropriate power line voltage on the fuse module Ground the Instrument This product is provided with protec tive earth terminals To minimize shock hazard
268. rograms for Excel 7 0 This section contains two example programs written using Excel macros Visual Basic for Applications to control the 34970A 34972A Using Excel you can send SCPI commands to configure the instrument and then 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 244 into the Send Commands module Then type the text for configuring the interface as shown on page 245 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
269. ront panel You can set the resolution to 4 5 or 6 full digits plus a digit which can only be a 0 or 1 To increase your measurement accuracy and improve noise rejection select 6 digits To increase your measurement speed select 4 digits 10 216 5 VDC This is the 10 VDC range 512 digits are displayed 045 23 mVDC This is the 100 mVDC range 41 digits are displayed 113 325 6 OHM This is the 100 ohm range 61 digits are displayed For temperature measurements 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 6 digits The only way to control the reading rate for AC measurements is by changing the channel delay see page 105 or by setting the AC filter to the highest frequency limit see page 131 117 Chapter 4 Features and Functions General Measurement Configuration The specified resolution 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 resolution Measurements taken during the Monitor function also use the specified resolution Changing the number of digits does more than just change the resolution of
270. rovide 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 Oscilloscope 1 o Test 1 mooom o oaa Test 2 i Test 3 l EOE AR l 1 NG l Patch Cable l EE EEE 1 4x 1 Multiplexer we een l r K o t Test4 oO Test 5 O t Test 6 I l C Test 7 I l 4 x 1 Multiplexer On the 34905A 50Q and 34906A 75Q RF multiplexers you can close only 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 C Cc 10S 10S E command OPEN does not apply To open a channel send the E command to another channel in the same bank 312 Chapter 7 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 Use the correct cable and connector for the circuit impedance 50Q or 75Q Note that it is difficult to visually differentiate a 50Q connector from a 75Q connector 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 34905A and 34906A do not automatically terminate open channels
271. rval scan to scan 45 96 IP address 189 IPTS 68 conversions 127 266 isothermal block 124 270 ITS 90 conversions 127 266 J jumper Totalize Threshold 154 211 junction temperature 267 K kelvins setting units 123 L labels Mx B scaling 46 137 stored states 57 LAN Connectivity 187 LAN Resetting 187 language SCPI syntax conventions 89 version query 173 LAN to GPIB Gateway 61 LAST annunciator 8 latch mode alarm output lines 145 limits alarms annunciators 142 clearing alarm outputs 146 configuring 47 default settings 48 142 interaction with Mx B 47 140 output connector location 9 10 output connector pinout 145 output latch mode 145 output slope polarity 146 output track mode 146 scan on alarm 100 setting limits 47 with readings 104 line voltage factory setting 34 fuse 34 selection 34 selector module 9 35 loading errors ac voltage 284 dc input resistance 277 input bias current 278 lock link kit rack mounting 38 low frequency limit ac current 133 frequency 135 350 Index M MAC Address 190 magnetic field errors 260 mainframe firmware revision 167 maintenance clearing relay count 169 reading relay count 169 319 matrix switching combining 308 MAX annunciator 8 maximum reading during scan 169 Measure key 30 32 41 94 MEASure command 95 Measurement Complete signal 112 measurement range autorange 115 overload 115 sel
272. s View the last 100 scanned readings from memory last min max and average View the first 20 alarms in the alarm queue reading and time alarm occurred View up to 10 errors 34970A or 20 errors 34972A in the error queue Read the number of cycles for the displayed relay relay maintenance feature 42 Chapter 2 Front Panel Overview Front Panel Menu Reference Store and recall instrument states Store up to five instrument states in non volatile memory Assign a name to each storage location e Recall stored states power down state factory reset state or preset state Configure the remote interface 34970A Select the GPIB address Configure the RS 232 interface baud rate parity and flow control Configure the remote interface 34972A e Configure the LAN settings IP Address Hostname DHCP etc e Configure the USB settings Enable USB ID etc Configure and use the USB drive Logging etc 43 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 En
273. s input ports Note that a Le J from the front panel resets only the port currently selected both ports are not reset Front Panel Operation After selecting the port press F 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 To add a digital read to a scan list choose the following item DIO READ From the front panel only you can specify whether you want to use binary or decimal format USE DECIMAL USE BINARY 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 SENS DIG DATA BYTE 302 Read port 02 SENS DIG DATA WORD 301 Read both ports together 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 152 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 The totalizer channel is num
274. s 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 Switching typical signal levels will result in relay lifetimes from 1 000 000 to 10 000 000 operations 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 Low voltage switching lt 30V and low current switching lt 10 mA applications will yield relay lifetimes to 10 000 000 operations RF switching applications seldom exhibit relay lifetimes exceeding 1 000 000 operations due to more stringent contact resistance requirements typically less than 0 20 The following table shows the time required to reach the specified number of switch operations for several switching speeds Continuous Switching Operations Switching Speed 100 000 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 321 Voltage Switched Chapter 7 Tutorial Relay Life and Preventive Maintenance Relay Life As a relay is used the contacts begin to wear and the resistance of the closed contacts increases The initial contac
275. sight BenchLink Data Logger produces by default The default field separator is a comma but you can use the following command to specify a different separator MMEMory FORMat READing CSEParator TAB COMMa SEMicolon 179 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A A sample file is shown below Sweep Time Chan 201 VDC Chan 202 VDC 1 01 26 2009 08 07 12 237 0 36823663 1 23895216 2 01 26 2009 08 07 13 237 0 62819233 0 98372939 3 01 26 2009 08 07 14 237 0 38238212 0 39382906 4 01 26 2009 08 07 15 237 0 46773299 0 55543345 5 01 26 2009 08 07 16 237 1 32323567 0 21213335 The channel numbers and the associated units are shown in the header row Ifthe row limit feature is ON and the data spills over into multiple files scan numbering continues where it left off in the previous file Thus the first scan in the second data file would be number 65 536 the first scan in the third data file would be number 131 071 and so on 180 Chapter 4 Features and Functions USB Drive Front Panel 34972A USB Drive Front Panel 34972A This section gives information on configuring the USB drive with the front panel For more information about using the USB drive see Mass Memory USB Subsystem 34972A on page 174 For more information on the SCPI commands available to configure the USB drive over the remote interface see the MMEMory Subsystem in hte Keysight
276. sign 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 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 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 69 Chapter 3 System Overview Signal Routing and Switching Signal Routing and Switching The switching capabilities of the plug in modules available with the 34970A 34972A 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 34970A 34972A Relay Maintenance System automatically counts the cycles of each relay in the instrument and stores the total count in non volatile memory o
277. 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 Scaling is applied using the following equation Scaled Reading Gain x Measurement Offset 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 If 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 If 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 dec
278. splay Annunciators HE Agilent 348 70A TA ACGUISTION SWITCH UNIT Oa r p SCAN MON VIEW CONFIG X ADRS RMT ERROR EXT ONCE MEM 34970A MEM 34972A AUTO 34972A LAST MIN MAX SHIFT 4w oc Aa Ee Scan is in progress or enabled Press and hold again to turn off Monitor mode is enabled Press again to turn off Scanned readings alarms errors or relay cycles are being viewed Channel configuration is in progress on displayed channel Measurement is in progress Instrument is addressed to listen or talk over the remote interface Instrument is in remote mode remote interface Hardware or remote interface errors are detected Press to read errors Instrument is configured for an external scan interval Scan Once mode is enabled Press to initiate and hold key to disable Reading memory overflow new readings will overwrite the oldest readings A USB drive is connected to the instrument annunciator on or data is being written to or read from the USB drive annunciator flashing USB logging is active Viewed data is the ast reading stored during most recent scan Viewed data is the minimum reading stored during most recent scan Viewed data is the maximum reading stored during most recent scan Gur has been pressed Press again to turn off 4 wire function is in use on displayed channel Offset compensation is enabled on displayed channel Alarms are enabled on displ
279. st 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 84970A 84972A Service Guide for more information The security code is set to either HP034970 or AT0384972 depending on the product number 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 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 192 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 or AT034972 depending on the product number 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 Front Panel Operatio
280. t and the user have a separate written agreement with warranty terms covering the material in this doc ument that conflict with these terms the warranty terms in the separate agreement shall control Technology Licenses The hardware and or software described in this document are fur nished under a license and may be used or copied only in accordance with the terms of such license Restricted Rights Legend If software is for use in the perfor mance of a U S Government prime contract or subcontract Software is delivered and licensed as Commercial computer software as defined in DFAR 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a or as Restricted computer software as defined in FAR 52 227 19 June 1987 or any equivalent agency regulation or contract clause Use duplication or disclosure of Software is subject to Keysight Technologies stan dard commercial license terms and non DOD Departments and Agencies of the U S Government will receive no greater than Restricted Rights as defined in FAR 52 227 19 c 1 2 June 1987 U S Government users will receive no greater than Limited Rights as defined in FAR 52 227 14 June 1987 or DFAR 252 227 7015 b 2 November 1995 as applicable in any technical data Safety Notices CAUTION A CAUTION notice denotes a hazard It calls attention to an operating procedure practice or the like that if not correctly per fo
281. t is shipped from the factory 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 If you select the GPIB interface you must select a unique address for the instrument The GPIB address is displayed on the front panel when you turn on the instrument 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 Front Panel Operation GPIB 488 RS 232 Remote Interface Operation SYSTem INTerface GPIB RS232 184 Chapter 4 Features and Functions Remote Interface Configuration 34970A 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 front panel only Select one of the following 1200 2400 4800 9600 19200 38400 57600 factory setting or 115200 baud 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 Front Panel Operation 19200 BAUD Parity Selection RS 232 You can select the parity for RS 232 operation The
282. t pattern read from the port will be displayed until you press another key turn the knob or until the display times out Note To add a digital input channel to a scan list press and select the DIO READ choice 49 gt S Chapter 2 Front Panel Overview To Write to a Digital Output Port To Write to a Digital Output Port The multifunction module 84907A has two non isolated 8 bit input output ports which you can use for outputting digital patterns 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 Enter the bit pattern editor Notice that the port is now converted to an output port DOUT 00000000 DOUT Binary Display Shown Edit the bit pattern Use the knob and C or D 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 press the key and select USE BINARY or USE DECIMAL 240 DOUT Decimal Display Shown 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 50 i Chapter 2 Front Panel Overview To Read the Totalizer Count To Read the Totaliz
283. t 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 1Q should be replaced The graph below shows the typical contact resistance characteristics of the relays used on the 34970A 34972A switching modules Typical Relay Lifetime 4 8 Full Load Typical Signals No Load 3 2 10 X o 5 02 oO gt amp e l l det 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 low power As the power switched increases relay life deteriorates A 300V 240V 180V 120V 7 60V fT Maximum Switching Capacity 0 2A 0 4A O06A 08A 1A Armature 34901A 34903A 34904A 34908A 10mA 20mA 30mA 40mA 50mA Reed 34902A _ Current Switched 322 Chapter 7 Tutorial Relay Life and Preventive 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 an
284. tage Measured 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 264 Chapter 7 Tutorial Measurement Fundamentals Measurement Fundamentals This section explains how the 34970A 34972A 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 74 To From i Analog O Signal Analog to Main Earth 77 Input Conditionin Digital Processor Re
285. ted if you send the MEASure or CONFigure command with autorange enabled 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 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 Keysight Service Center if this error is reported 222 350 410 420 430 440 Chapter 5 Error Messages Execution Errors Error queue overflow The error queue is full because more than 10 errors 34970A or 20 errors 84972A 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
286. 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 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 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 in chapter 8 Differential Error Integral Error Vout Vprogrammed 320 Chapter 7 Tutorial Relay Life and Preventive Maintenance Relay Life and Preventive Maintenance The 34970A 34972A 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 169 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 graph
287. temperature extremes or physical stress If possible keep the temperature gradient across the extension wire to a minimum 274 Chapter 7 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 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 Distributed GL TSG t Too L PFO p Capacitance fl S Garret Biers HI R R R i R R R pee Hp wt fo Lo Distributed Y A e a I Resistance WITHOUT SHIELD YP E D MM 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 C
288. ter 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 critical 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 PTFE 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 257 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 75
289. ter 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 196 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 Rcl 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 Operation Scan List Reading Memory Min Max and Average Scan Trigger Source Scan Interval used with TRIGger SOURce TIMer 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 34901A 34902A 34908A 34903A 34904A 34905A 34906A 34907A System Related Operations Display State Error Queue Stored Sta
290. terface GPIB IEEE 488 address selection 53 55 183 cable 61 interface selection 53 55 183 remote interface RS 232 serial baud rate 54 56 cable 61 flow control 54 parity 54 stop bits 54 reset mode totalizer 51 92 resistance measurements 352 Index 2 wire ohms 289 4 wire ohms 289 connections 28 nominal RTD 127 offset compensation 132 291 ranges 28 resolution half digit 117 selecting 118 vs integration time 120 revision number firmware 34970A 167 plug in modules 167 RF cable kits SMB to BNC 209 RF multiplexers insertion loss 311 sources of error 311 VSWR 311 RFI radiation 259 ribbon cables 67 RMT annunciator 8 rosette strain gage 294 ROUTe CHAN ADV SOUR mand 114 ROUTe CHAN DELay command 105 ROUTe CHAN FWIRe command 114 com ROUTe MON DATA command 172 ROUTe MON STATe command 172 ROUTe SCAN command 95 RS 232 serial interface baud rate 184 cable 23 61 connector location 9 flow mode 185 parity 184 selecting interface 183 RTD measurements 127 alpha a 127 connections 28 conversion accuracy 265 measurement tutorial 266 measurement units 123 supported types 28 123 RTS CTS flow mode RS 282 185 rubber bumpers removing 37 S safety notices 3 Sample annunciator 8 sample programs C and C 248 Excel 7 0 241 scale temperature units 123 scaling Mx B custom label 46 137 default gain
291. terface programming Rules for Using a Channel List Many of the SCPI commands for the 34970A 34972A include a scan_list or ch_list parameter which allow you to specify one or more channels Square brackets indicate optional keywords or parameters Braces enclose parameter choices within a command string Triangle brackets lt gt separate parameters for which you must substitute a value A vertical bar separates multiple parameter choices The channel number has a form sec where s is the slot number 100 200 or 300 and cc is the channel number You can specify a single channel multiple channels or a range of channels as shown below The following command configures a scan list to include only channel 10 on the module in slot 300 ROUT SCAN 310 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 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 89 Chapter 4 Features and Functions Scannin
292. tes 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 Not Changed Immediate 10 Seconds 1 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 All Channels Open All Channels Open Channels s11 and s21 Selected Both DIO Ports Input Totalizer Count 0 Both DACs 0 VDC Factory Reset State On Errors Not Cleared No Change 197 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 Rcl menu or SYSTem PRESet command from the remote interface Measurement Configuration Function Range Resolution Advanced Settings Totalizer Reset Mode Totalizer Edge Detect Scanning Operation 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 Configuration Alarm Output State Alarm Output Slope Module Hardware 34901A 34902A 34908A 34903A 34904A 34905A 34906A 34907A
293. tes assume use of socket connection VXI11 will be less 5 For fixed function and range readings to memory scaling alarms autozero off 332 Wi Module Specifications 34901A 34902A 34908A 34903A 34904A Chapter 8 Specifications Module Specifications 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 1 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 50W 50W 50W Isolation ch ch ch earth dc AC rms 300 V 300 V 300 V 300 V 300 V DC Characteristics Offset Voltage P lt 3uV lt 6 uV lt 3uV lt 3 pV lt 3uV Initial Closed Channel RI lt 10 lt 10 lt 1Q lt 0 20 lt 19 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 10 MHz 45 45 18 45 33 Capacitance HI to 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 Accuracyl 5 typical 0 8 C 0 8 C 0
294. th low sensitivity measuring capabilities to measure small resistance changes common in strain measurements Instruments with high resolution resistance measuring capabilities like the 34970A 34972A 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 cabling errors An initial unstrained gage resistance measurement is used as the reference Rj measurement from which strain AR R 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 1202 0 24mQ 0 1mQ 0 4 ne 1 pe 2 0 3502 0 70mQ 1 0mQ 1 4 ue 1 pe 2 0 10000 2 0 MQ 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 34970A 34972A front panel display You can use a custom measurement label to display readings in us micro strain directly The instrument will automatically add the micro u prefix based upon actual calculated values For more information on scaling see page 186 1 1 B M GER F Temperature Effects The resistive element of a st
295. 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 Range Input Level Reading Error Reading Error 9 p of reading 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 338 Chapter 8 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 Input Level Reading Error Range g p of reading Error Voltage 10 VDC 10 VDC 0 0004 lt 40 uV 10 VDC 1 VDC 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 x 100 Input Signal Level of input error Total Measurement Error 4 000 000 ppm of input error I
296. 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 120 for more information e The MEASure and CONFigure commands contain an optional resolution parameter which allows you to specify the resolution The instrument returns to 5 digits 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 resolution setting 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 118 Chapter 4 Features and Functions General Measurement Configuration Remote Interface Operation Specify the resolution in the same units as the measurement function not in number of digits For 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 CONFigure commands For example the following statement selects the 10 V
297. the instrument must be con nected to the ac power mains through a grounded power cable with the ground wire firmly connected to an electrical ground safety ground at the power outlet Any interruption of the protec tive grounding conductor or discon nection of the protective earth terminal will cause a potential shock hazard that could result in personal injury Do Not Operate in an Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Do Not Remove the Instrument Cover Only qualified service trained personal who are aware of the hazards involved should remove instrument covers Always disconnect the power cable and any external circuits before removing the instrument cover Do Not Modify the Instrument Do not install substitute parts or per form any unauthorized modification to the product Return the product to a Keysight Sales and Service Office for service and repair to ensure that safety features are maintained In Case of Damage Instruments that appear damaged or defective should be made inoperative and secured against unintended opera tion until they can be repaired by quali fied service personnel CAUTION Unless otherwise noted in the specifica tions this instrument or system is intended for indoor use in an installa tion category II pollution degree 2 environment per IEC 61010 1 and 664 respectively It is designed to operate at a maximum
298. the screw terminals Cable Tie Wrap optional Wiring Hints For detailed information on each module refer to the section starting on page 200 To reduce wear on the internal DMM relays wire like functions on adjacent channels e For information on grounding and shielding see page 259 The diagrams on page 28 show how to connect wiring to a multiplexer module for each measurement function 27 Chapter 1 Quick Start To Connect Wiring to a Module Thermocouple DC Voltage AC Voltage Frequency Thermocouple Types B E J K N R S T See page 351 for thermocouple color codes Ranges 100 mV 1 V 10 V 100 V 300 V 2 Wire Ohms RTD Thermistor 4 Wire Ohms RTD H R L H a Ranges 100 1 k 10 k 100 k 1 M 10 M 100 MQ L RTD Types 0 00385 0 00391 Thermistor Types 2 2 k 5k 10k l 1 R I gt aa aa a aG A a a Ml a a ae DC Current AC Current H sense L AM x Channel n source is automatically paired with L Channel n 10 sense on the 34901A or Channel n 8 sense on the 34902A Valid only on channels 21 and 22 on the 34901A Ranges 100 1 k 10 k 100 k 1 M 10 M 100 MQ Ranges 10 mA 100 mA 1A RTD Types 0 00385 0 00391 28 OE 1 Utility Utility Chapter 1 Quic
299. ther 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 us There are three common types of strain measurements as shown below Normal Strain e is a measure Force Force of the deformation along the F esta E axis of the applied force s La gt AL L L aL Shearing Strain y is a measure of the angular distortion of a body It is F AY approximated by the tangent q of the angle formed by the angular change between two line segments that were parallel in the undeformed state Poisson Strain v measures a property of materials known 1 VETESSE as the Poisson Ratio It is the F om F negative ratio of transverse GAAN nnn and longitudinal normal strain when a body has a i longitudinal tensile force applied v e e where 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 295 Chapter 7 Tutorial Measurement Fundamentals 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 insulatin
300. these connections 310 Chapter 7 Tutorial Matrix Switching Combining Matrices You can combine two or more matrix switches to provide more complex switching For example the 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 Z z 7 T Row 1 wae fee re AS Po AR ra Ea oe Z T Row 4 4 l We ve im if Col 1 ae gt Col 8 8 Rows 8 Columns lt Col 199 S Col8 SA HER LAL X 5 lt Row 1 NX i Aa SS SST Row 4 Matrix Module 2 311 Chapter 7 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 500 or 750 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 4 Source 1 Signal Generator l a l we External 9 o Source 2 r Power Meter Source 3 i mm Source 4 i i i l Me Sete et ohh De ete eee ees Set 4x 1 Multiplexer 4x 1 Multiplexer By using patch cables you can expand RF multiplexers to p
301. tically pairs channel n with channel n 10 84901A 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 Ory 2 2H HY To DMM Source lt f a Channel 1 Source LE O O AL Bank Relay l AL Channel 2 Source H Z o OH To DMM Sense Channel 11 Sense L O AL Channel 12 Sense 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 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 HI A Source R Sense LO 302 Chapter 7 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 34901A and 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 t
302. time Autozero is automatically turned off when you select an integration time less than 1 PLC You can set autozero from the remote interface only you cannot directly set autozero from the front panel 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 OFF and ONCE parameters have a similar effect Autozero OFF does not issue a new zero measurement Autozero ONCE issues an immediate zero measurement N ERO AUTO OFF ONCE ON lt ch_list gt 122 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 For more information on the types of temperature transducers see Temperature Measurements starting on page 267 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 499 to 2 1 KQ 2 2 KO 5 kQ 10 kQ a 0 00385 DIN IEC 751 44000 Series a 0 00391 Measurement Units The instrument can report temperature measurements in C
303. 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 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 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 151 Chapter 4 Features and Functions Digital Input Operations A Factory Reset RST command Instrument Preset SYSTem PRESet command and Card Reset SYSTem CPON command from the remote interface will reconfigure both ports a
304. 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 GPIB End Sub Continued on next page 248 Chapter 6 Application Programs Example Programs for Excel 7 0 Sub make Data arhescuanne 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 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 If Channel 1 Then Label the top of the data column and time stamp column Cells 4 columnIndex 2 Scan amp Str columnIndex Cells columnIndex 2 Font Bold True Cells 3 columnIndex 2 1 time stamp Cells columnIndex 2 1 min sec End If Get channel number put in column A for first scan o
305. ts 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 engineering 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 fr
306. tures and Functions Scanning with External Instruments 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 You can configure the event or action that notifies the 34970A 34972A 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 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 102 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 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 84901A or n 8 84902A to provide the s
307. two resistors that act as a voltage divider A typical attenuator circuit is shown below R1 HI WAV V signal Vatt LO lt R2 To select the attenuator components use the following equation R2 Vatt Vsignal R iR 1 2 One typical use for the shunt component is with 4 to 20 mA transducers A 50Q 1 0 5 watt resistor 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 309 Chapter 7 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 jer Z yg T Source 1 AI ASA he gt A a Z Za 2 Source 2 ae foe Lo F ae My a VI A B ZA e fo Pa Z Z Source 3 th S So 3 a L ae eae py Jnr NS a 4 a 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
308. ule diagram see page 213 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 14 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 BenchLink Data Logger 3 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 Error Messages Chapter 5 lists the error messages that may appear as you are working with the instrument Each listing contains enough information to help you diagnose and solve the problem Application Programs Chapter 6 contains several remote interface program examples to help you develop programs for your application Tutorial Chapter 7 discusses measurement considerations and techniques to help you obtain the best accuracies and reduce sources of measurement noise Specifications Chapter 8 lists the technical specifications for the
309. 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 34970A 34972A is designed and tested to meet performance better than mean 3 sigma of the published accuracy specifications 341 Chapter 8 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 intervals and within a stable
310. urrent 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 a a VDC to Input Amplifier and A Analog to Digital Converter Rs LO AC current measurements are very similar to DC 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 DC continuity in the test circuit Performing AC current 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 7 289 Chapter 7 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 l i j RS DMM i l Vs Source voltage Rs Source resistance Vp Burden voltage R Current shunt r
311. 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 characteristics 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 34970A 34972A front panel allows you to control the integration period for precise rejection of noise signals 76 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 resul
312. used by ground loops 261 noise rejection normal mode 120 nominal impedance cabling 255 nominal resistance RTD default 127 values 127 normal mode rejection 120 264 NPLC 120 264 vs channel delays 106 null stored as offset B 137 number of bits vs integration time 120 number of digits 117 vs integration time 120 O OC annunciator 8 offset B Mx B scaling 46 136 offset compensation 132 291 offset voltages 122 On Standby switch 23 ONCE annunciator 8 Open key 33 output format alarm queue data 144 output lines alarms 141 145 P parity RS 232 factory setting 184 selecting 54 184 351 Index pasting channel configuration 32 PCL 120 264 vs channel delays 106 period measurements connections 28 sources of error 297 plug in module description 34901A 200 34902A 202 34903A 204 34904A 206 34905A 208 34906A 208 34907A 210 34908A 212 plug in module information connecting wiring 27 default settings 198 firmware revision 167 installing in mainframe 27 reading relay count 169 strain relief 27 poisson strain 293 polarity alarm output lines 146 Power Standby switch 23 power cord 23 power failure during scan 93 power line cycles 120 264 power down recall 57 93 160 power line fuse factory setting 34 location 9 10 35 part number 34 replacing 35 power line voltage factory setting 34 fuse 34 selection 34 selector
313. usion 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 34970A 34972A 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 124 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 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
314. ut non isolated Vin L lt 0 8V TTL Vin H gt 2 0V TTL Vout L lt 0 8V lout 400 mA Vout H gt 2 4V lout 1mA Vin H Max lt 42V with external open drain pull up Alarming Maskable pattern match or state change Speed 4 ms max alarm sampling Latency 5 ms typical to 34970A 34972A alarm Read Write Speed output 95 s Totalize Input Maximum Count Totalize Input 226 _ 1 67 108 863 100 kHz max rising or falling edge programmable Signal Level 1 Vp p min 42 Vpk max Threshold OV or TTL jumper selectable Gate Input TTL HI TTL LO or none County Reset Manual or Read Reset Read Speed 85 s Analog Voltage DAC Output DAC 1 2 12V non isolated earth referenced Resolution 1 mV lout 10 mA max Settling Time 1 ms to 0 01 of output Accuracy of output mV 1year 5 C 0 25 20 mV Temp Coefficient 0 015 1 mV C 1 Limited to 40 mA total for all three slots six DAC channels 336 Wi Product and Module Dimensions Chapter 8 Specifications Product and Module Dimensions 374 0 mm 348 3 mm a Module All dimensions are shown in millimeters 337 Chapter 8
315. ute 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 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 HI 104 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 measurement on the channel The programmed channel delay overrides the default channel delay that the instrument automatically adds to each channel Scan List Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Channal Nalav e 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 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 Front Panel Operation ELAY TIME Remote Interface Operation The
316. ution to 6 digits Select the slow AC filter 3 Hz to 300 kHz Frequency and Period Measurements Set the resolution to 6 digits 343 Chapter 8 Specifications Configuring for Highest Accuracy Measurements 344 Index If you have questions relating to the operation of the 834970A 34972A call 1 800 452 4844 in the United States or contact your nearest Keysight Technologies Sales Office Symbols 4 digit 117 B Mx B scaling offset 136 half digit 117 M Mx B scaling gain 136 OPEN T C message 125 RST command 196 TRG command 98 Numerics 34901A module channel numbering 200 description 200 module overview 12 200 screw terminal diagram 201 simplified schematic 200 wiring log 201 34902A module channel numbering 202 description 202 module overview 12 202 screw terminal diagram 203 simplified schematic 202 wiring log 203 34903A module channel numbering 204 description 204 304 module overview 13 204 RC protection circuitry 305 screw terminal diagram 205 simplified schematic 204 snubber circuitry 305 wiring log 205 34904A module channel numbering 206 combining matrices 309 description 206 308 module overview 13 206 screw terminal diagram 207 simplified schematic 206 wiring log 207 34905A module 50W channel numbering 208 description 208 310 module overview 13 208 screw terminal diagram 209 simplified schematic 208 wiring log
317. ve the internal DMM from the 34970A 34972A or disable it see Internal DMM Disable on page 145 92 Power Fails Chapter 4 Features and Functions Scanning Power Failure 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 is restored If the instrument is in the middle of a scan sweep when power fails all readings from that partially completed sweep will be discarded a sweep is one pass through the scan list For example assume that your scan list includes four multiplexer channels and you want to 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 resume scanning at the beginning of the third scan sweep If 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 If you replace a module with a module of the same type while power is off the instrument will continue scann
318. viously stored readings To stop a scan execute the ABORt command 95 Chapter 4 Feat Scanning ures and Functions Scan Interval You can configure the event or action that controls the onset of each sweep through You can set specific inte the scan list a sweep is one pass through the scan list the instrument s internal timer to automatically scan at a rval 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 You can start a scan by sending a software command from the remote interface MI EASure 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 In 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 countdown 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 Scan List 1 sweep N mt Scan to Scan interval 0 to 99 59 59 hours 96 Chapt
319. y 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 wn ENS VOLT AC BAND 3 203 Select the slow filter 8 Hz 131 Chapter 4 Features and Functions Resistance Measurement Configuration Resistance Measurement Configuration To connect resistances to the module s screw terminals see page 28 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 100Q 1kQ 10kQ 100kQ 1MQ 10MQ 100 MQ 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 100Q 1 kQ and 10 kQ ranges For detailed information about offset compensation see page 293 The instrument disables offset compensation when the measurement function is changed or after a Factory Reset RST comma
320. you read it 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 Up to 20 alarms can be logged in the alarm queue If more than 20 alarms are generated they will be lost only the first 20 are saved 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 or Instrument Preset SYSTem PRESet command does not clear the alarm queue 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 C and E 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 143 Chapter 4 Features and Functions Alarm Limits 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 04 01 14 39 40 058 101 2 1 l 1 Reading with Units 31 009 C 4 Channel Number 2 D
321. z Enter the command CD DATA to log onto the USB drive Enter the command DIR to obtain a directory of the USB drive Enter the command CD MY00012345 20091210 134523123 to change to the directory containing the data you wish to download from the USB drive to your local computer Of course the exact directory name will vary Enter the command ascii to ensure that you transfer the appropriate file type Enter the command get dat00001 csv to download that specific file or enter mget csv to download all files ending in CSV The MEM annunciator will not flash during the download Enter the command delete data00001 csv to delete a specific file or enter mdelete csv to delete all files ending in CSV Enter the command quit to leave the FTP session Refer to your computer s FTP documentation for further details 175 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A 176 Chapter 4 Features and Functions Mass Memory USB Subsystem 34972A SCPI Commands This section concentrates on the features available from the front panel you can also control the mass memory subsystem with the following SCPI commands ory FORMat READing CSEParator lt column_separator gt tj EMory FORMat READing CSEParator EMory FORMat R R READing RLIMit lt row_limit gt R EMory FORMat READing RLIMit EMory LOG ENABle lt state gt EMory LOG ENABle EMory EXPort
322. z 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 eta Sear Came Single Point Ground ae ie Circuit A Circuit B Circuit C Parallel Grounds V i Separate Grounds 259 LO HI Chapter 7 Tutorial System Cabling and Connections 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 sh

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