HP 34970A Relay Life, Relay Load

Chapter 8 Tutorial

Relay Life and Preventative Maintenance

Relay Life

As a relay is used, the contacts begin to wear and the resistance of the closed contacts increases. The initial contact resistance of a relay is typically 50 mΩ (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 1Ω should be replaced. The graph below shows the typical contact resistance characteristics of the relays used on the HP 34970A switching modules.

Relay Contact Resistance

Typical Relay Lifetime

Full Load Typical Signals No Load

1Ω

0Ω

10k

100k

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.

Voltage Switched

300V	Maximum Switching Capacity
240V

180V

120V

60V

0.2A	0.4A	0.6A	0.8A	1A	Armature (HP 34901A, 34903A, 34904A, 34908A)

10 mA	20 mA	30 mA	40 mA	50 mA	Reed (HP 34902A)

Current Switched

400

Contents

User’s Guide Data Acquisition / Switch Unit Convenient Data Logging Features Flexible Data Acquisition/ Switching Features The Front Panel at a Glance Denotes a menu key. See the next page for details on menu operation The Front-PanelMenus at a Glance Tip Display Annunciators WARNING The Rear Panel at a Glance HP BenchLink Data Logger Software at a Glance The Plug-InModules at a Glance HP 34901A 20-ChannelArmature Multiplexer HP 34902A 16-ChannelReed Multiplexer HP 34903A 20-Channel Actuator/General-PurposeSwitch HP 34904A 4x8 Two-WireMatrix Switch HP 34905/6A Dual 4-ChannelRF Multiplexers HP 34907A Multifunction Module HP 34908A 40-Channel Single-EndedMultiplexer In This Book Contents Contents Page Page Page Quick Start To Prepare the Instrument for Use To Prepare the Instrument for Use 1 Check the list of supplied items 2Connect the power cord and turn on the instrument 3Perform a complete self-test Installing HP BenchLink Data Logger Software Installing HP BenchLink Data Logger Software Installation Procedure If you are running Windows 95 or Windows NT 4.0 ® Settings | Control Panel Start Creating Installation Floppy Disks Note Create disks On-LineHelp System To Connect Wiring to a Module To Connect Wiring to a Module 1Remove the module cover 2Connect wiring to the screw terminals 3Route wiring through strain relief 4Replace the module cover Thermocouple DC Voltage / AC Voltage / Frequency 2-WireOhms / RTD / Thermistor DC Current / AC Current 4-WireOhms / RTD To Set the Time and Date To Set the Time and Date 1Set the time of day 2Set the date To Configure a Channel for Scanning To Configure a Channel for Scanning 1Select the channel to be added to the scan list 2Select the measurement parameters for the selected channel 3Run the scan and store the readings in non-volatilememory SCAN 4View the data from the scan To Copy a Channel Configuration To Copy a Channel Configuration 1Select the channel to copy the configuration from 2Select the copy function 3Select the channel to copy the configuration to 4Copy the channel configuration to the selected channel To Close a Channel To Close a Channel 1 Select the channel 2 Close the selected channel 3 Open the selected channel If the Instrument Does Not Turn On If the Instrument Does Not Turn On 1Verify that there is ac power to the instrument 2Verify the power-linevoltage setting 3Verify that the power-linefuse is good Remove the power cord To Adjust the Carrying Handle To Adjust the Carrying Handle Bench-topviewing positions To Rack Mount the Instrument To Rack Mount the Instrument To remove the rubber bumper, stretch a corner and then slide it off To rack mount a single instrument, order adapter kit Page Front-PanelOverview Chapter 2 Front-PanelOverview Front-PanelMenu Reference Front-PanelMenu Reference chapter shows examples of using the front-panelmenus Page To Monitor a Single Channel To Monitor a Single Channel 1Select the channel to be monitored 2Enable monitoring on the selected channel MON To Set a Scan Interval To Set a Scan Interval 1Select the interval scan mode 2Select the scan count 3 Run the scan and store the readings in memory To Apply Mx+B Scaling to Measurements To Apply Mx+B Scaling to Measurements 1Configure the channel 2Set the gain and offset values 3Select the custom label 4Run the scan and store the scaled readings in memory To Configure Alarm Limits To Configure Alarm Limits 2Select which of the four alarms you want to use 3Select the alarm mode on the selected channel 4 Set the limit value 5Run the scan and store the readings in memory To Read a Digital Input Port To Read a Digital Input Port 1Select the Digital Input port 2Read the specified port ' 2 8 7 Binary Display Shown '287 Decimal Display Shown To Read the Totalizer Count To Read the Totalizer Count 1Select the totalizer channel 2Configure the totalize mode 3Read the count To Output a DC Voltage To Output a DC Voltage 1Select a DAC Output channel 2Enter the output voltage editor 3Set the desired output voltage 4Output the voltage from the selected DAC To Configure the Remote Interface To Configure the Remote Interface 1Select the HP-IBinterface 2Select the HP-IBaddress 3 Save the change and exit the menu 1 Select the RS-232interface 2Select the baud rate 3Select the parity and number of data bits 4Select the flow control method 5 Save the changes and exit the menu 7(67BUDFNB Page System Overview Chapter 3 System Overview Data Acquisition System Overview You can use the PC to provide easy configuration and data presentation ∙ You can use a single PC to monitor multiple instruments and measurement points while performing other PC-basedtasks Measurement Software Data Logging and Monitoring HP BenchLink Data Logger Automated Testing with Multiple Instruments The HP 34970A Data Acquisition / Switch Unit Plug-InModules System Cabling The plug-inmodules have screw-terminalconnectors 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 Transducers and Sensors Alarm Limits Signal Routing and Switching Signal Routing and Switching Switching Topologies Multiplexer Switching Matrix Switching Form C (SPDT) Switching Measurement Input Measurement Input The Internal DMM Signal Conditioning, Ranging, and Amplification Analog-to-Digital Conversion (ADC) Main Processor Scanning Page Scanning With External Instruments The Multifunction Module Digital Input Totalizer Control Output Control Output Digital Output Voltage (DAC) Output The Actuator / General-PurposeSwitch Page Features and Functions SCPI Language Conventions SCPI Language Conventions Rules for Using a Channel List scc Scanning Scanning Rules for Scanning MEM Page Page Power Failure Adding Channels to a Scan List To Build a Scan List From the Front Panel: To Build a Scan List From the Remote Interface: Interval Scanning Page Scan Once ONCE External Scanning Ext Trig Connector EXT Scanning on Alarm Page Scan Count Reading Format Channel Delay Automatic Channel Delays Viewing Readings Stored in Memory LAST MIN MAX AVG Page Single-ChannelMonitoring Single-ChannelMonitoring Page Scanning With External Instruments Scanning With External Instruments Page Page General Measurement Configuration General Measurement Configuration Measurement Range Page Measurement Resolution This is the 10 Vdc range, 51⁄2 digits are displayed This is the 100 mVdc range, 41⁄2 digits are displayed This is the 100 ohm range, 61⁄2 digits are displayed Page Page Custom A/D Integration Time Page Autozero Temperature Measurement Configuration Temperature Measurement Configuration Measurement Units Thermocouple Measurements Page Page RTD Measurements Page Thermistor Measurements Voltage Measurement Configuration Voltage Measurement Configuration DC Input Resistance 20 Hz Resistance Measurement Configuration Resistance Measurement Configuration Offset Compensation Current Measurement Configuration Current Measurement Configuration Page Frequency Measurement Configuration Frequency Measurement Configuration Low Frequency Timeout Mx+B Scaling Measure Page Alarm Limits Page Four TTL alarm outputs are available on the Alarms For complete details, refer to “Using the Alarm Output Lines” on page The following table shows the different combinations of Page Viewing Stored Alarm Data 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) Using the Alarm Output Lines Alarms Connector Page Using Alarms With the Multifunction Module OUTPut:ALARm[1|2|3|4]:SOURce (@<ch_list>) To configure alarms on the specified digital input channel, use the following commands (also see the example on the following page) the following commands EQUal Example: Configuring an Alarm on a Digital Input Digital Input Operations Digital Input Operations Page Totalizer Operations Totalizer Operations Page Page Digital Output Operations Digital Output Operations DAC Output Operations DAC Output Operations System-RelatedOperations State Storage Page Error Conditions ERROR Self-Test Display Control Real-TimeSystem Clock Internal DMM Disable Firmware Revision Query Relay Cycle Count Page SCPI Language Version Query Remote Interface Configuration Remote Interface Configuration HP-IBAddress Remote Interface Selection Baud Rate Selection (RS-232) Parity Selection (RS-232) None Flow Control Selection (RS-232) Page Calibration Overview Calibration Overview Calibration Security To Unsecure for Calibration To Secure Against Calibration To Change the Security Code Calibration Message Calibration Count Factory Reset State Factory Reset State FACTORY RESET Instrument Preset State Instrument Preset State PRESET Multiplexer Module Default Settings Multiplexer Module Default Settings Module Overview Module Overview Reference Module HP 34901A 20-ChannelMultiplexer HP 34901A 20-ChannelMultiplexer When making 4-wireresistance measurements, the instrument automatically Page HP 34902A 16-ChannelMultiplexer HP 34902A 16-ChannelMultiplexer Page HP 34903A 20-ChannelActuator HP 34903A 20-ChannelActuator Page HP 34904A 4x8 Matrix Switch HP 34904A 4x8 Matrix Switch Page HP 34905A/6A Dual 4-ChannelRF Multiplexers HP 34905A/6A Dual 4-ChannelRF Multiplexers These modules consist of two independent 4-to-1multiplexers Page HP 34907A Multifunction Module HP 34907A Multifunction Module Digital Input/Output Totalize Input Analog Output (DAC) Page HP 34908A 40-Channel Single-EndedMultiplexer HP 34908A 40-Channel Single-EndedMultiplexer Page Page Remote Interface Reference SCPI Command Summary SCPI Command Summary Rules for Using scan_list and ch_list Parameters scan_list ch_list Scan Measurement Commands (see page 226 for more information) TCouple Monitor Commands (see page 237 for more information) Scan Configuration Commands RELative Scan Statistics Commands (see page 233 for more information) Scan Memory Commands (see page 235 for more information) Scanning With an External Instrument (see page 239 for more information) TIMer Temperature Configuration Commands (see page 219 for more information) INTernal Voltage Configuration Commands (see page 223 for more information) Resistance Configuration Commands (see page 224 for more information) Current Configuration Commands Valid only on channels 21 and 22 on the HP 34901A multiplexer module Frequency and Period Configuration Commands (see page 214 for more information) Mx+B Scaling Commands (see page 244 for more information) Alarm Limit Commands (see page 247 for more information) LATCh NEGative Digital Input Commands (see page 255 for more information) BYTE Totalizer Commands (see page 256 for more information) Digital Output Commands (see page 258 for more information) DAC Output Commands Switch Control Commands (see page 259 for more information) Scan Triggering Commands (see page 228 for more information) State Storage Commands (see page 261 for more information) System-RelatedCommands (see page 264 for more information) Interface Configuration Commands (see page 269 for more information) Status System Commands (see page 286 for more information) Calibration Commands (see page 292 for more information) Service-RelatedCommands (see page 294 for more information) IEEE 488.2 Common Commands Simplified Programming Overview Simplified Programming Overview Using the MEASure? Command Using the CONFigure Command Using the range and resolution Parameters range resolution Using the READ? Command Caution Using the INITiate and FETCh? Commands Page Page The MEASure? and CONFigure Commands The MEASure? and CONFigure Commands MEASure? Command Syntax MEASure:TEMPerature?5 TCouple,{B|E|J|K|N|R|S|T|DEF} MEASure:TEMPerature? {RTD|FRTD},{85|91|DEF} MEASure:TEMPerature? {THERmistor},{2252|5000|10000|DEF} MEASure:VOLTage:DC MEASure:VOLTage:AC [{<range>|AUTO|MIN|MAX|DEF} MEASure:RESistance MEASure:FRESistance MEASure:CURRent:DC MEASure:CURRent:AC MEASure:FREQuency MEASure:DIGital:BYTE? (@<scan_list>) MEASure:TOTalize? {READ|RRESet} ,(@<scan_list>) CONFigure Command Syntax CONFigure:TEMPerature {TCouple},{B|E|J|K|N|R|S|T|DEF} CONFigure:TEMPerature {RTD|FRTD},{85|91|DEF} CONFigure:TEMPerature {THERmistor},{2252|5000|10000|DEF} CONFigure:VOLTage:DC CONFigure:VOLTage:AC CONFigure:RESistance CONFigure:FRESistance CONFigure:CURRent:DC CONFigure:FREQuency CONFigure:PERiod CONFigure:DIGital:BYTE (@<scan_list>) CONFigure:TOTalize {READ|RRESet} ,(@<scan_list>) CONFigure? [(@<ch_list>)] Setting the Function, Range, and Resolution Setting the Function, Range, and Resolution [SENSe:]FUNCtion "<function>"[,(@<ch_list>)] [SENSe:]FUNCtion? [(@<ch_list>)] Page Page 100 ms TEMPerature :NPLC {0.02|0.2|1|2|10|20|100|200|MIN|MAX}[,(@<ch_list>)] VOLTage:DC RESistance FRESistance Temperature Configuration Commands General Temperature Commands UNIT [SENSe:]TEMPerature:TRANsducer [SENSe:]TEMPerature Thermocouple Commands [SENSe: TEMPerature:TRANsducer :TCouple:TYPE :TCouple:TYPE Select the thermocouple type to use on the specified channels :CHEC :RJUN [SENSe:]TEMPerature:RJUNction? [(@<ch _list>)] +2.89753100E+01 RTD Commands :REF +1.00000000E+02 Thermistor Commands SENSe: Voltage Configuration Commands INPut ZERO:AUTO {OFF|ONCE|ON}[,(@<ch_list>)] ZERO:AUTO? [{(@<ch_list>)] Resistance Configuration Commands Current Configuration Commands Frequency Configuration Commands Frequency Configuration Commands Scanning Overview Scanning Overview Page Scanning Commands :SCAN (@<scan_list>) :SCAN ROUTe:SCAN:SIZE :SOURce {BUS|IMMediate|EXTernal|ALARm{1|2|3|4}|TIMer} :SOURce :TIMer {<seconds>|MIN|MAX} :TIMer :COUNt {<count>|MIN|MAX|INFinity} :COUNt :CHANnel:DELay <seconds>[,(@<ch_ list>)] :CHANnel:DELay? [(@<ch_list>)] ABORt INITiate READ *TRG Reading Format Commands :READing:ALARm {OFF|ON} :READing:ALARm FORMat :READing:CHANnel {OFF|ON} :READing:CHANnel :READing:TIME {OFF|ON} :READing:TIME :READing:UNIT {OFF|ON} :READing:UNIT :READing:TIME:TYPE {ABSolute|RELative} CALCulate:AVERage:MINimum? [(@<ch_list>)] CALCulate:AVERage:MINimum:TIME? [(@<ch_list>)] CALCulate:AVERage:MAXimum? [(@<ch_list>)] CALCulate:AVERage:MAXimum:TIME? [(@<ch_list>)] CALCulate:AVERage:AVERage? [(@<ch_list>)] CALCulate:AVERage:PTPeak? [(@<ch_list>)] CALCulate:AVERage:COUNt? [(@<ch_list>)] CALCulate:AVERage:CLEar [(@<ch_list>)] DATA:LAST DATA:POINts DATA:REMove? <num_rdgs SYSTem:TIME:SCAN FETCh Single-ChannelMonitoring Overview Single-ChannelMonitoring Overview :MONitor (@<channel>) :MONitor :MONitor:STATe {OFF|ON} :MONitor:STATe ROUTe:MONitor:DATA Scanning With an External Instrument :SOURce {BUS|IMMediate|EXTernal|TIMer} :COUNt {<value>|MIN|MAX|INFinity} :CHANnel:ADVance:SOURce {EXTernal|BUS|IMMediate} :CHANnel:ADVance:SOURce INSTrument :DMM {OFF|ON} INSTrument:DMM:INSTalled Mx+B Scaling Overview Mx+B Scaling Overview :SCALe:UNIT :SCALe:UNIT? [(@<ch_ list>)] CALCulate:SCALe:OFFSet:NULL (@<ch_list>) Alarm System Overview Alarm System Overview Page Page :ALARm[1|2|3|4]:SOURce (@<ch_list>) :ALARm[1|2|3|4]:SOURce :LIMit:UPPer <value>[,(@<ch_ list>)] :LIMit:UPPer? [(@<ch_list>)] :LIMit:LOWer <value>[,(@<ch_ list>)] :LIMit:LOWer? [(@<ch_list>)] Alarm Output Commands :ALARm:MODE {LATCh|TRACk} :ALARm:MODE :ALARm:SLOPe {NEGative|POSitive} :ALARm:SLOPe Digital I/O Alarm Commands :COMPare:TYPE {EQUal|NEQual}[,(@<ch_list>)] :COMPare:TYPE? [(@<ch_list>)] :COMPare:DATA <data>[,(@<ch_list>)] :COMPare:DATA? [(@<ch_list>)] Page Digital Input Commands [SENSe:]DIGital:DATA:{BYTE|WORD}? [(@<ch_list>)] Totalizer Commands TOTalize:TYPE {READ|RRESet}[,(@<ch_list>)] TOTalize:TYPE? [(@<ch_list>)] [SENSe:]TOTalize:CLEar:IMMediate [(@<ch_list>)] [SENSe:]TOTalize:DATA? [(@<ch_list>)] Digital Output Commands :DIGital:DATA[:{BYTE|WORD}] <data> ,(@<ch_list>) :DIGital:DATA[:{BYTE|WORD}]? (@<ch_list>) SOURce:DIGital:STATe? (@<ch_list>) DAC Output Commands Switch Control Commands ROUTe:DONE State Storage Commands *SAV {0|1|2|3|4|5} *RCL {0|1|2|3|4|5} MEMory:STATe :NAME {1|2|3|4|5} [,<name>] :NAME? {1|2|3|4|5} MEMory:STATe:DELete {0|1|2|3|4|5} :RECall:AUTO MEMory:STATe:VALid? {0|1|2|3|4|5} MEMory:NSTates System-RelatedCommands SYSTem:DATE <yyyy>,<mm>,<dd SYSTem:DATE SYSTem:TIME <hh>,<mm>,<ss.sss SYSTem:TIME *IDN SYSTem:CTYPe? {100|200|300} DIAGnostic :POKE:SLOT:DATA {100|200|300}, <quoted_string>5 :PEEK:SLOT:DATA? {100|200|300} DISPlay {OFF|ON} DISPlay DISPlay :TEXT :TEXT INSTrument :DMM {OFF|ON} SYSTem:ERRor Interface Configuration Commands SYSTem:INTerface {GPIB|RS232} SYSTem:LOCal SYSTem:REMote SYSTem:RWLock RS-232Interface Configuration RS-232Interface Configuration RS-232Configuration Overview None / 8 data bits 1 bit RS-232Flow Control Modes RS-232Data Frame Format Connection to a Computer or Terminal RS-232Troubleshooting Modem Communications Modem Communications The SCPI Status System The SCPI Status System What is a Condition Register What is an Event Register What is an Enable Register HP 34970A Status System The Status Byte Register Bit Definitions – Status Byte Register Using Service Request (SRQ) and Serial Poll Using *STB? to Read the Status Byte Using the Message Available Bit (MAV) To Interrupt Your Bus Controller Using SRQ To Determine When a Command Sequence is Completed The Questionable Data Register Bit Definitions – Questionable Data Register Page The Standard Event Register Read the error queue using the SYSTem:ERRor? command Bit Definitions – Standard Event Register Page The Alarm Register Bit Definitions – Alarm Register The Standard Operation Register Bit Definitions – Standard Operation Register Status System Commands Status Byte Register Commands *STB *SRE *SRE Questionable Data Register Commands STATus:QUEStionable:CONDition STATus:QUEStionable[:EVENt] STATus:QUEStionable:ENABle <enable_value Standard Event Register Commands *ESR *ESE *ESE Alarm Register Commands STATus:ALARm:CONDition STATus:ALARm[:EVENt] STATus:ALARm:ENABle <enable_value STATus:ALARm:ENABle Standard Operation Register Commands STATus:OPERation:CONDition STATus:OPERation[:EVENt] STATus:OPERation:ENABle <enable_value STATus:OPERation:ENABle DATA:POINts:EVENt:THReshold <num_rdgs DATA:POINts:EVENt:THReshold Miscellaneous Status Register Commands *CLS STATus:PRESet Calibration Commands CALibration CALibration:COUNt CALibration:SECure:CODE <new_code CALibration:SECure:STATe {OFF|ON},<code CALibration:SECure:STATe CALibration:STRing <quoted_string CALibration:STRing CALibration:VALue <value Service-RelatedCommands DIAGnostic:DMM:CYCLes DIAGnostic:DMM:CYCLes:CLEar {1|2|3} DIAGnostic:RELay:CYCLes? [(@<ch_list>)] DIAGnostic:RELay:CYCLes:CLEar [(@<ch_list>)] *WAI An Introduction to the SCPI Language An Introduction to the SCPI Language Command Format Used in This Manual Command Separators Using the MIN and MAX Parameters Querying Parameter Settings SCPI Command Terminators IEEE-488.2Common Commands SCPI Parameter Types Numeric Parameters Discrete Parameters Boolean Parameters String Parameters Channel List Parameters Using Device Clear Using Device Clear Page Error Messages Execution Errors Execution Errors Invalid character Syntax error Invalid separator GET not allowed Header suffix out of range Invalid character in number Numeric overflow Too many digits Numeric data not allowed Block data not allowed Expression data not allowed Trigger ignored INIT ignored Trigger deadlock Data stale System error Error queue overflow Query Query UNTERMINATED after indefinite response Instrument Errors Instrument Errors Channel list: slot number out of range Channel list: channel number out of range Channel list: empty scan list Memory lost: stored state Settings conflict: calculate limit state forced off Settings conflict: module type does not match stored state Settings conflict: trig source changed to IMM Settings conflict: chan adv source changed to IMM Settings conflict: DMM disabled or missing Not able to execute while scan initiated Not able to accept unit names longer than 3 characters Not able to accept character in unit name Not able to perform on more than one channel Not able to recall state: it is empty Module not able to perform requested operation Not able to perform requested operation Part of a 4-wirepair 307Incorrectly configured ref channel I/O processor: isolator framing error I/O processor: isolator overrun error Communications: RS-232framing error Communications: RS-232overrun error Communications: RS-232parity error Self-TestErrors Calibration Errors Calibration Errors Cal: security disabled by jumper Cal: secured Cal: invalid secure code Cal: secure code too long Page Plug-InModule Errors Page Application Programs Example Programs for Excel Example Programs for Excel Insert Tools Page Page Page Page Page Page Example Programs for C and C++ Example Programs for C and C++ Page Page Page Page Tutorial System Cabling and Connections System Cabling and Connections Cable Specifications Page Grounding Techniques Shielding Techniques Separation of High-Leveland Low-LevelSignals Sources of System Cabling Errors Radio Frequency Interference Thermal EMF Errors Noise Caused by Magnetic Fields Noise Caused by Ground Loops Low-Level AC Measurement Errors Measurement Fundamentals Measurement Fundamentals Rejecting Power-Line Noise Voltages Temperature Measurements RTD Measurements Thermistor Measurements Thermocouple Measurements Page Page Page Thermocouple Types Sources of Error in Thermocouple Measurements Reference Junction Error Diffusion Error Shunt Impedance Shielding Calculation Error DC Voltage Measurements Signal Conditioning for DC Measurements Sources of Error in DC Voltage Measurements Common Mode Rejection Noise Caused by Injected Current Loading Errors Due to Input Resistance Loading Errors Due to Input Bias Current AC Voltage Measurements Signal Conditioning for AC Measurements True RMS AC Measurements Making High-Speed AC Measurements Sources of Error in AC Voltage Measurements Crest Factor Errors (non-sinusoidal inputs) Page AC Loading Errors Page Measurements Below Full Scale Temperature Coefficient and Overload Errors Current Measurements Sources of Error in DC Current Measurements Sources of Error in AC Current Measurements Resistance Measurements 4-Wire Ohms Measurements Page Offset Compensation Sources of Error in Resistance Measurements External Voltages Settling Time Effects High-Resistance Measurement Errors Strain Gage Measurements Stress Strain Sensors Common Uses for Strain Gages Making Strain Gage Measurements Temperature Effects Frequency and Period Measurements Sources of Error in Frequency and Period Measurements Low-LevelSignal Multiplexing and Switching Low-LevelSignal Multiplexing and Switching One-Wire (Single-Ended)Multiplexers (for more information on the purpose of an isothermal block, see Two-WireMultiplexers for more information on the purpose of an isothermal block, see Four-WireMultiplexers Signal Routing and Multiplexing Sources of Error in Multiplexing and Switching Page Actuators and General-PurposeSwitching Actuators and General-PurposeSwitching Snubber Circuits RC Protection Networks Using Varistors Using Attenuators ModuleReference Matrix Switching Matrix Switching Combining Matrices RF Signal Multiplexing RF Signal Multiplexing Sources of Error in RF Switching Multifunction Module Digital Input Digital Output Using an External Pull-Up Driving External Switches Totalizer Totalizer Errors Voltage (DAC) Output DAC Errors Relay Life and Preventative Maintenance Relay Life and Preventative Maintenance Relay Life Relay Load Switching Frequency Replacement Strategy Specifications Chapter 9 Specifications DC, Resistance, and Temperature Accuracy Specifications DC, Resistance, and Temperature Accuracy Specifications DC Measurement and Operating Characteristics DC Measurement and Operating Characteristics AC Accuracy Specifications AC Accuracy Specifications AC Measurement and Operating Characteristics AC Measurement and Operating Characteristics Measurement Rates and System Characteristics Measurement Rates and System Characteristics Module Specifications Page Typical AC Performance Graphs Typical AC Performance Graphs Software Specifications Product and Module Dimensions Product and Module Dimensions To Calculate Total Measurement Error To Calculate Total Measurement Error Understanding the “ % of reading ” Error Understanding the “ % of range ” Error Total Measurement Error Interpreting Internal DMM Specifications Interpreting Internal DMM Specifications Number of Digits and Overrange Sensitivity Resolution Accuracy 24-HourAccuracy 90-Dayand 1-YearAccuracy Temperature Coefficients Configuring for Highest Accuracy Measurements Configuring for Highest Accuracy Measurements DC Voltage, DC Current, and Resistance Measurements: AC Voltage and AC Current Measurements: Frequency and Period Measurements: Index Index