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Strain Gage Multiplexer Overview

1. Set Bridge Set Bridge LO G Jumpers E LO G I s Vs Jumpers C LO HI G LO HI G LO HI G LO HI Sc Ey ED E1alo EleLo E1oL 7 2064 260 Ra Ch 3 Ch 2 Ch Ch O 1 4 Bridge 1 2 Bridge Full Bridge L A E2 E2 E1 E E2 E1 E E2 Eq EZ E1 E TE ET E2 E PEIFE2 E ET E2I FE E1 Use with be Sot th 5 E1357A cad E1351 66201 EN e4 Serevidriver f Bridge Selection Jumpers Bridge Excitation Voltage Terminals E1355 f 2 1b Bridge Wiring Diagrams Figure 2 1B Terminal Module Configuration The eight bridge selection jumpers Figure 2 1B select the bridge arrangement for each channel individually Thus a single strain gage multiplexer can have any combination of 1 4 1 2 and full bridge arrangements connected to the module When making 4 or l bridge measurements the corresponding bridge selection jumper must be set to the V4 2 position When making full bridge measurements DC voltage measurements or 2 wire resistance measurements the channel s bridge selection jumper must be set to the FULL position When the excitation voltage which drives the Wheatstone Bridge circuitry is externally supplied the voltage is connected to the Vs terminals on
2. Rg4 VE 7 l tension Rg1 g gn compression Ra3 Rg2 TOP SPECIMEN Rg4 IE Rg ES LONGITUDINAL we POISSON GAGE BOTTOM SPECIMEN Ras VE Rg2 ae LONGITUDINAL N GAGE POISSON GAGE E1355 fig4 15 Figure 4 15 Bending Poisson Arrangement 62 Understanding the Strain Gage Multiplexers Chapter 4 Poisson Full Bridge In applications where the specimen is stressed lengthwise the measurement FPOisson sensitivity is increased and temperature compensation is achieved when the gages are mounted to the specimen as indicated in Figure 4 16 Figure 4 16 Poisson Arrangement Measurements Using an External Voltmeter Set Up Procedure This section describes how measurements are made using a strain gage multiplexer switchbox and a voltmeter external to the HP 75000 Series B or Series C mainframe When making strain measurements with an external voltmeter the strain gage multiplexer is configured for V4 1 2 and full bridge measurements as described in Chapters 1 and 2 The external voltmeter is connected to the multiplexer through the HI LO and G terminals on the multiplexer terminal module Figures 2 7 2 8 Measuring strain with an external voltmeter involves measuring the Wheatstone bridge output voltage Vout and the bridge excitation voltage Vs under strained and unstrained conditions These m
3. STATe Queries state of Trig Out port ROUTe CLOSe lt channel_list gt Close channel s CLOSe lt channel_list gt Query channel s closed OPEN lt channel_list gt Open channel s OPEN lt channel_list gt Query channel s opened SCAN channel list Define channels for scanning SCAN MODE mode Selects appropriate tree isolation switches for measurements SCAN MODE Returns present state of scan mode SCAN PORT port Enables tree isolation switches closure as part of a measurement SCAN PORT Query analog bus state SETTling TIME lt time gt lt channel_list gt s delay between trigger pulse and channel closed pulse SETTling TIME MIN MAX channel list Returns current parameter in SETTling TIME SENSe STRain GFACtor lt gage_factor gt lt channel_list gt Specifies the gage factor for the strain channel STRain GFACtor lt channel_list gt Queries the gage factor STRain POlSson lt poisson_ratio gt lt channel_list gt Specifies the Poisson ratio for the strain channel STRain POlSson channel list Queries the Poisson ratio STRain UNSTrained reference channel Downloads the unstrained reference voltage STRain UNSTrained channel list Queries the unstrained reference voltages STATus OPERation ENABle number Enables the Operation Status Register to set a bit in the Status Register OPERation EVEN1 Returns status of Operation Status Register SYSTem CDE
4. ER g X Bottom e C shield e amp EED MN gt Poisson 1 2 Bridge X HPOisson Bending 1 2 Bridge E1355 f 2 5 Figure 2 5 Connecting Strain Gages in 1 2 Bridge Arrangements Chapter 2 Connecting Strain Gages to the Multiplexers 29 Full Bridge Diagrams SING CHANNELS 0 3 H L G TOP E E L SAMPLE 4 j E lon E H AE Eto L pu mi M G e G SHIELD E2 m G 9 E D 1 4 1 2 AA BOTTOM 0000 SAMPLE f p E P E2 J gt 8 Full Bridge orologio Y FULL e CHANNELS 4 7 SHOWN e db SEE e ER FBENding H L G TOP H L G TOP E i z we FE ve i E i SUELE ve EM ool HE LSS a E i P EM ENDE Suns HE 2 en 2g t E L gt E2 Il E2 gt A o Ve E SiD UU al la lo al e e TE ET E2 FPOIsson ESET E2 FRPoisson E1355 192 8 Figure 2 6 Connecting Strain Gages in Full
5. HP 3458 Multimeter a o 2 F Oo EE E1355A Fig2 8 Figure 2 8 Connecting FET Strain Gage Multiplexers to an External Voltmeter 32 Connecting Strain Gages to the Multiplexers Chapter 2 Chapter 3 Making Strain Gage Measurements About This Chapter Using the Example Prog ams Programming Language This chapter contains example programs which make strain gage measurements with various bridge configurations The examples in this chapter include e Single Channel 4 Bridge Measurements Page 35 e Multi Channel V4 Bridge Measurements Page 36 e Dynamic Strain Measurements 0 Page 37 e Rosette Measurements lee Page 39 e Single Channel Bending Full Bridge Measurement t ssla Dens ertet eed eite Page 40 e Relay Strain Gage Measurements with an External Voltmeter aio bes He tee eR er ERI A EE es Page 41 FET Strain Gage Measurements with an External Voltineter cita ira ed miS Page 43 e Measurements with Downloaded Unstrained Referentes ci ao dr Ve er Page 46 The purpose of the chapter is to provide example programs that show you how to make strain gage measurements and to provide programs that can be used directly in your applications The example programs are shown in the HP BASIC language and assume the multimeter is controlled from an HP 9000 Series 3
6. The ratio of voltages on the upper and lower bridge legs should be 1 40 1 To perform the internal half bridge voltage diagnostic your system should be configured as follows 1 If the bridge excitation voltage is externally supplied connect the supply to the terminal module as shown in Figure C 1 Set the voltage to 5 0V 2 If desired connect the bridge arrangement to the bridge completion channels Strain gages do not have to be connected for this diagnostic Use care when externally supplying the bridge excitation voltage Voltages greater than 5 4V can damage the bridge completion resistors Appendix C Strain Gage Diagnostics 111 Procedure 1 Measure the voltage on the upper bridge leg MEASure VOLT DC 111 2 Measure the voltage on the lower bridge leg MEASure VOLT DC 110 3 Calculate the ratio of upper bridge leg to lower bridge leg voltages The following example determines the internal half bridge voltage ratio The program assumes the strain gage multiplexer is used with the HP E1326B E1411B Multimeter as part of a scanning multimeter instrument The computer syntax used is HP BASIC running on a Hewlett Packard Series 300 computer Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Measure the voltage across the upper leg of the internal V5 bridge resistor OUTPUT 70903 MEAS VOLT DC 111 ENTER 70903 V_upper Measure the voltage across the lower leg of the internal Y
7. 2601 Channel list required Sending a command requiring a channel list without the channel list Appendix E Strain Gage Multiplexer Error Messages 137 Notes 138 Strain Gage Multiplexer Error Messages Appendix E CLS 98 ESE 98 ESE 98 ESR 98 DN 98 OPC 98 OPC 98 RCL 98 RST 98 100 SAV 98 SRE 98 SRE 98 STB 98 TRG 96 98 100 TST 98 100 W AT 98 A A16 Address Space 120 121 Abbreviated Commands 66 ABORt Subsystem 68 99 Address A16 address space 120 121 base 121 channel 22 HP IB 21 interface card 21 logical 19 21 primary 21 registers 120 secondary 21 Analog Bus cables 22 port 86 ARM Subsystem 69 99 ARM COUNt 69 ARM COUNt 69 Index HP E1355A 56A 57A 58A Modules User s Manual Base Address 121 Bending full bridge measurements FBENDing 61 half bridge measurements HBENDing 59 poisson full bridge measurements FBPoisson 62 Biaxial Stress State Equations 105 Bit Map channel register 125 control register 125 129 device type register 124 127 direct channel configuration register 132 direct control register 132 manufacturer ID register 123 126 scan channel configuration register 131 scan channel delay register 128 130 scan control register 128 130 status register 124 127 tree switch register 125 Block Diagrams 52 Boolean Command Parameters 67 Bridge configu
8. Write Undefined 93 92 91 90 Closing Tree Relay Closing a Tree Relay Writing a one 1 to bit 3 2 1 or 0 closes tree relay 93 92 91 or 90 respectively When making strain measurements using a switchbox tree relay 90 must be closed DC voltage measurement Channel Reg ister The Channel Register is used to close the relay strain gage multiplexer internal channels and bridge completion channels base 0816 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Ch15 Ch14 Ch13 Ch12 Ch7 Ch6 Ch5 Ch4 Ch11 Ch10 Ch9 Ch8 Ch3 Ch2 Ch1 ChO Int Int Int Int Bco Bc Bc Bcl Int Int Int Int Bc Bc Bc Bc Int B c Internal Channels and Bridge Completions Channels The relay strain gage multiplexer contains internal channels Int which access the diagnostics and bridge completion channels B c to which the strain gages are connected Closing Channels Closing a Channel Writing a one 1 to bit 0 through 15 closes the corresponding internal or bridge completion channel Writing a zero 0 to the bit opens the channel Appendix D Strain Gage Register Based Programming 125 FET Multiplexer Registers The READ Registers ID Register There are five READ and six WRITE registers on the FET strain gage multiplexer The following READ registers are located on the FET strain gage multiplexer D Register base 0016 Device Type Re
9. Example Closing Multiplexer Channels These examples close channel 00 of switchbox multiplexer card number 1 Relay Multiplexer Switchbox CLOS 100 Closes channel 0 of multiplexer 1 FET Multiplexer Switchbox SCAN MODE VOLT Selects the voltage scanning mode SCAN PORT ABUS Selects the analog bus port CLOS 100 Closes channel 0 of multiplexer 1 CLOSe ROUTe CLOSe channel list returns the current state of the channel queried The channel list is in the form ccnn The command returns 1 if the channel is closed or returns 0 if the channel is open Comments Query is Software Readback The ROUTe CLOSe command returns the current software state of the channel specified It does not account for relay hardware failures Example Query Multiplexer Channel Closure CLOS 100 100 closes channel 0 of multiplexer 1 CLOS 100 Query channel 0 Chapter 5 Strain Gage Multiplexer Command Reference 81 OPEN ROUTe OPEN channel list opens multiplexer channels specified in the channel list The channel list is in the form ccnn ccnn ccnn ccnn ccnn or cenn cenn ccnn ccnn where cc card number 00 99 and nn channel number 00 15 Parameters Parameter Name Parameter Type Range of Values channel list Numeric cc00 cc15 Comments Opening Channels relay and FET To open asingle channel use OPEN ccnn for multiple channels use OPEN ccnn ccnn sequential
10. 3 Insert Wire Into Terminal Tighten Screw Use wire Size 16 26 Gage Reinstall Clear 26 Connecting Strain Gages to the Multiplexers Chapter 2 Strain Gage Wiring Diagrams Wiring Considerations Using a Twisted Shielded Cable This section contains the wiring diagrams for the strain measurement configurations available with the multiplexers The section also shows how to connect an external voltmeter to a switchbox in order to make strain measurements The example programs in Chapter 3 also refer to these diagrams Before connecting strain gages to the bridge completion channels consider the following To ensure the most accurate measurements possible a twisted shielded cable should be used when connecting the strain gages to the bridge completion channels see Figure 2 3 SHIELD SPECIMEN G LO HI Ch 3 Ch 2 Ch 1 G SHIELD E2 E1 E E2 E14 E1355 f 2 3 E2 ET E Strip length 6mm To open fy Pry slot with J Key screwdriver f Wire Gage Figure 2 3 Using a Twisted Shielded Cable Connecting the shield to the specimen and to the G guard terminal of the channel will help keep noise induced currents out of the conductor H L leads The guard connection also takes advantage of the multiplexer s Wagner
11. Related Commands TRIGger SOUR DBUS TRIGger SOURce IMM Example Setting the Maximum Settling Time TRIG SOUR DBUS Selects external trigger source SCAN MODE VOLT Selects the voltage scanning mode SCAN PORT ABUS Selects the ABUS port SETT TIM MAX 100 Sets the maximum channel closed pulse delay SCAN 100 107 Sets channel list INIT Starts scanning cycle SETTling TIME ROUTe SETTling TIME MIN MAX channel list returns the current setting for a specified channel MIN or MAX returns the minimum and maximum allowable settings Parameters Parameter Name Parameter Type Range of Values MIN MAX Numeric MIN 1 usec MAX 32768 usec Comments Returned Value This is given in exponential notation Example Querying the Settling Time SETT TIM 16E 6 Sets delay 16 usec SETT TIM Returns 1 600000E 005 Chapter 5 Strain Gage Multiplexer Command Reference 87 SENSe Subsystem Syntax STRain GFACtor Parameters Comments Example The SENSe command subsystem is an HP E1326B E1411B Multimeter subsystem used to specify the Gage Factor and Poisson Ratio for strain gage measurements This subsystem is also used for downloading unstrained references prior to strain measurements Refer to Chapter 5 in the HP E1326B E1411B User s Manual for more information on this subsystem SENSe STRain GFACtor lt gage_factor gt lt channel_list gt GFACtor channel list POISson
12. Selecting a Specific Module to be Monitored Send the card number in a switchbox with the DISPlay MONitor CARD command Selecting the Present Module to be Monitored Use the DISPlay MONitor CARD AUTO command to select the last multiplexer addressed by a switching command for example ROUTe CLOSe e RST Condition DISPlay MONitor CARD AUTO Select Multiplexer 2 in a Switchbox for Monitoring DISP MON CARD 2 Selects multiplexer 2 in a switchbox Chapter 5 Strain Gage Multiplexer Command Reference 73 MONitor STATe DISPlay MONitor STATe mode turns the monitor mode on or off Parameters Parameter Name Parameter Type Range of Values mode Boolean 0 1 ON OFF Comments Monitoring Switchbox Channels DISPlay MONitor STATe ON or DISPlay MONitor STATe 1 turns the monitor mode on to show the channel state of the selected multiplexer DISPlay MONitor STATe OFF or DISPlay MONitor STATe O turns the monitor mode off e Selecting the Module to be Monitored Use the DISPlay MONitor CARD number AUTO command to select the multiplexer Monitor Mode on an HP 1301 Mainframe Display The following shows the types of displays you will get when monitoring relay and FET multiplexer channels SWITCH 112 Chan 0 1 Relay channels 0 and 1 are closed SWIICH 1129 Chan 1 FET channel 1 is closed e RST Condition DISPlay MONitor STATe OFF 0 Example Enabling the Monitor M
13. o O eg Switch is set to the O position a Switch is set to the 1 position 0 ie Strain Gage Multiplexer 1 o follo oF et ol fo fol HP E1326 1411 Multimeter 1 ojo eV e o le lo o 1 Logical Address 112 ol 5 e ol lol lo s e o Pm 24 Secondary n of 5 8 ol o of odo Secondary Address 14 7 654321 Des T 7 6 85 43 2 1 0 Card number 1 a uw 1 o o lo oF of lo lo et Strain Gage Multiplexer Logical 1 o let lo a o o o et Sirain Gage Multiplexer ofog ed elle e fog fog elo Address 25 Card Number 1 o edis e e ed ed og felo Logical Address 113 Er iu die E I BOW DT m Card number 2 E Strain Gage Mullipl rain Gage Multiplexer Vor e e ey of 2 a Oji Strain Gage Multiplexer Logical Ola a et fo o Yo 3 P Logical Address 114 0 fof lof ed o e log o ojo Address 26 Card Number 2 o ej gt e fe ed ed el logo Card number 3 B62 54 uM ES WU qeu Da cd iZ ddp 0 Scanning Multimeter Switch Box E1355A fig1 5 Figure 1 5 Creating a Scanning Multimeter and a Switchbox 20 Getting Started with the Strain Gage Multiplexers Chapter 1 Instrument Instruments in an HP 75000 Series B or Series C mainframe are located Add ressing with an HP IB address The HP IB address is a combination of the computer s interface select code the primary HP IB address of the mainframe s system instrument and the secondary HP IB address of the virtual instrument Addresses of this form in an HP BASIC stateme
14. ENTER 70903 Strn rdgs PRINT Stm rdgs NEXT J PRINT WAIT 5 Continued on Next Page 46 Making Strain Gage Measurements Chapter 3 OUTPUT 70903 STR GFAC 2 11E 6 91 00 102 CALL Ref load Unstr FOR J 1 TO 5 OUTPUT 70903 MEAS STR QUAR 100 102 ENTER 70903 Strn_rdgs PRINT Strn_rdgs NEXT J END This subprogram measures the unstrained references queries the references land then stores the references in a computer variable for later use SUB Ref meas Unstr OUTPUT 70903 CAL STR 100 102 OUTPUT 70903 STR UNST 100 102 ENTER 70903 Unstr SUBEND This subprogram downloads the unstrained references prior to the strain measurements SUB Ref load Unstr FOR 0 TO 2 OUTPUT 70903 STR UNST Unstr 1 100 1 NEXT SUBEND Comments e This program makes 4 bridge measurements on channels 0 1 and 2 of multiplexer card number 1 The wiring diagram used is on page 28 e Since each strain measurement must have an unstrained reference the unstrained references are downloaded prior to each set of measurements The unstrained references can be stored on disk for later use Chapter 3 Making Strain Gage Measurements 47 Notes 48 Making Strain Gage Measurements Chapter 3 Chapter 4 Understanding the Strain Gage Multiplexers About This Chapter This chapter describes the strain measurement procedure used by the examples in Chapter 3 and also describes the measurem
15. The first Edition of the manual is Edition 1 The Edi tion number increments by 1 whenever the manual is revised Updates which are issued between Editions contain replacement pages to correct or add additional information to the current Edition of the manual Whenever a new Edition is created it will contain all of the Update information for the previous Edition Each new Edition or Update also includes a revised copy of this documentation his tory page Edition nib rp be nene is MA pU August 1990 Editi n Dro oun E ecole Ret Pee eese es October 1993 Editori 34 ore eve eru E DP EE CREE NET YS August 1995 Safety Symbols Instruction manual symbol affixed to prod uct Indicates that the user must refer to the N Alternating current AC manual for specific WARNING or CAU TION information to avoid personal injury or damage to the product eme Direct current DC Indicates hazardous voltages Indicates the field wiring terminal that must be connected to earth ground before operat l ing the equipment protects against electri Calls attention to a procedure practice or cal shock in case of fault WARNING condition that could cause bodily injury or death Calls attention to a procedure practice or con Frame or chassis ground terminal typi CAUTION dition that could possibly cause damage to b or cally connects to the equipment s metal equipment or permanent loss of data frame WARNINGS The following genera
16. Trig Out BNC is pulsed each time a channel is closed during scanning Output Pulse The pulse is a 5 V negative going pulse Trig Out Port Reserved by Switchboxes The Trig Out resource is a system resource and can only be reserved by one switchbox instrument at a time Related Commands ROUTe SCAN TRIGger SOURce e RST Condition OUTPut STATe OFF port disabled Enabling Trig Out Port OUTP ON Enables Trig Out port for pulse output OUTPut STATe queries the present state of the Trig Out port The command returns 1 if the port is enabled or 0 if disabled Query Trig Out Port State OUTP ON Enables Trig Out port for pulse output OUTP STAT Query port enable state Chapter 5 Strain Gage Multiplexer Command Reference 79 ROUTe The ROUTe subsystem controls switching and scanning operations for the multiplexer modules in a switchbox configuration Subsystem Syntax ROUTe CLOSe channel list CLOSe channel list OPEN channel list OPEN channel list SCAN channel list MODE mode MODE PORT port PORT SETTling TIME time lt channel_list gt TIME MIN MAX lt channel_list gt CLOSe ROUTe CLOSe channel list closes multiplexer channels specified in the channel list For the relay strain gage multiplexers the channel list for CLOSe is in the form ccnn ccnn ccnn or ccnn ccnn where cc card number 00 99 and nn cha
17. component assembly and when the mainframe is turned on Note When the terminal card is not attached the system identifies the multiplexer as an HP E1351A 16 channel FET multiplexer when the card ID switches are in the OPEN 0 position HP E1345 66201 HP E1351 66201 Switch is set to the 0 position Switch is set to the 1 position E1355A fig 1 Jumper Setting for the 1356A Figure 1 1 Checking the Card ID Jumper Switch Chapter 1 Getting Started with the Strain Gage Multiplexers 15 Setti ng the Card ID n certain applications it may be necessary for the system to identify the Switch FET strain gage multiplexer without the terminal card attached Figure 1 2 shows the card ID switch settings which identify the HP E1357A and HP E1358A FET Strain Gage Multiplexers Note Make certain the card ID switch setting matches the terminal card used If they do not match a configuration error may occur or the wrong terminal card may be identified HP E1351 66201 al qavo ai qavo HP E1357A HP E1358A Switch is set to the 0 position Switch is set to the 1 position E1355A fig1 2 Figure 1 2 Identifying the HP E1357A E1358A 16 Getting Started with the Strain Gage Multiplexers Chapter 1 Selecting the The multiplexer s IRQ jumper sw
18. diagnostic to the bridge completion channels 3 Place the specimen in a constant preferably unstrained state throughout the procedure CAUTION Use care when externally supplying the bridge excitation voltage Voltages greater than 5 4V may damage the bridge completion resistors 114 Strain Gage Diagnostics Appendix C Procedure Note This diagnostic requires that an internal channel 12 or 13 be closed with a bridge completion channel 0 7 simultaneously Since the FET multiplexer can close only one channel at a time the shunt verification diagnostic is only used with the relay strain gage multiplexers 1 Measure the unstrained reference voltage on the bridge completion channel which the diagnostic is performed CALibration STRain channel 2 Measure the simulated tension strain MEASure STRain QTENsion channel The channel specified is the bridge completion channel 0 7 Internal channel 13 is closed automatically by the command 3 Measure the simulated compressive strain MEASure STRain QCOMpression channel The channel specified is the bridge completion channel 0 7 Internal channel 12 is closed automatically by the command The following example measures the simulated tension and compression strain The program assumes the relay strain gage multiplexer is used with the HP E1326B E1411B multimeter as part of a scanning multimeter instrument The computer syntax used is HP BASIC running on a Hewlett Pack
19. poisson ratio channel list POlSson channel list UNSTrained reference channel UNSTrained channel list SENSe STRain GFACtor gage factor channel list specifies the gage factor for the strain gage on the channel specified A gage factor must be specified for each channel Parameter Name Parameter Type Range of Values gage factor Numeric as specified channel list Numeric 00 07 One gage factor must be specified for each channel measured measurement in microstrain Specifying the Gage Factor STR GFAC 2 11E 6 100 The gage factor must be specified before the strain is measured Specifying the gage factor with an exponent of E 6 returns the strain Specifies the gage factor reading returned in microstrain 88 Strain Gage Multiplexer Command Reference Chapter 5 STRain GFACtor Parameters Comments Example STRain POISson Parameters Comments Example STRain POISson Parameters Comments Example SENSe STRain GFACtor lt channel_list gt returns the gage factor set for the channel specified Parameter Name Parameter Type Range of Values channel_list Numeric 00 07 e Returned value is given in exponential notation e g 2 110000E 006 Querying the Gage Factor STR GFAC 100 Queries the gage factor for channel 0 SENSe STRain POISson lt poisson_ratio gt lt channel_list gt specifies the p
20. throughout the procedure Use care when externally supplying the bridge excitation voltage Voltages greater than 5 4V may damage the bridge completion resistors 108 Strain Gage Diagnostics Appendix C A H L GTH L GTH L C O0000000000000000000000000000000 0000000000000000000000000000000 G L HTG L HTG L H 000000000000000 o o QJM4 O OJM5 O OJM6 O L S EE ur L OM O OM O OJMO O H 67 re H H L G yVst4 TEA 1 1 4 1 2 1 1 o 1 4 1 2 ea 0000000 00 0 O Of 5 9900 O O O jO o g 9000 mjo 0 0 0 000000 0 off TB1 oooo TB6 TB7 3 0000 ga 2 0000 oloooo 7 9 ru HLG I pus O JM14 OJO JM15 O O JM16 O O JM17 O 9er 29192 O JM13 OJO JM12 O OJM11 OJO JM10 O Worm 4 d BL UB 6566 VOLTMETER e 3555 G L HI GL HI GL HI GLH BRIDGE BRIDGE CH3 CH2 CH1 CHO OR2 OJO R21 0 SEP EA PE ere Ele E AE E AE SERE TAR CH4 CHS CHD CH7 O R2 Of O RB O E E1 E2 E E1 E2 E E1 E2 E E1 E2 1 O000 00000 00 O TB2 1 000000 000 TBS o oJ lo o e ojo 5 f VRI RO R7JO O Qo O O R6 O O os RB f 782 Power L SUPPLY Figure C 1 Externally Supplied Bridge Excitation Voltage Procedure The leadwire resistance is determined with the following parameters the voltage across the lower leg 1kQ internal
21. 1 kl a witch is set to the 1 position E1355A figt 3 Figure 1 3 The IRQ Jumper Switch Chapter 1 Getting Started with the Strain Gage Multiplexers 17 Internally Supplied Bridge Excitation Voltage INSTALL JUMPERS AS SHOWN A feature of the strain gage multiplexer is the availability of an internally supplied bridge excitation voltage This voltage which drives the multiplexer s Wheatstone Bridge strain measurement circuitry Chapter 4 is capable of driving eight channels of full bridge measurements HP E1545 66201 Ferg HP E1351 66201 ps TO INCREASE PROTECTION m d ERES INSTALL A ONE AMP FUSE HP part number 2110 0665 IN PLACE OF THE WIRE SHORT Figure 1 4 Internally Supplied Bridge Excitation Voltage Relay Multiplexer Excitation Voltage CAUTION The internal bridge excitation voltage for the HP E1355A E1356A relay strain gage multiplexers is 5V fused at 4A This voltage is accessed by installing jumpers on the component assembly as indicated in Figure 1 4 Note however that this signal may not be stable enough or pure enough for some strain measurements If jumpers are installed and then the 5V Bridge Excitation is shorted the main fuse on the PC board may blow and reset the mainframe This would set all instruments in the mainframe to their power on state To increase protection install a
22. 128 130 scanning 135 settling time 87 status register 127 switchbox 84 tree isolation switches 86 Format common commands 65 SCPI commands 65 FPOisson poisson full bridge 63 HP E1355A 56A 57A 58A Modules User s Manual Index 141 Full Bridge bending FBENding 61 bending poisson FBPoisson 62 bridge completion circuitry 55 measurements 61 63 poisson FPOisson 63 single channel bending measurements 40 terminals used 25 wiring diagram 30 Functional Description 13 Fuses 18 G Gage Factor 88 Gage of Wire 27 106 Getting Started 13 22 Guard Voltage Diagnostic 116 H H L G Voltmeter Terminals 25 Half Bridge bending HBENding 59 bridge completion circuitry 54 dummy gage 60 internal voltage diagnostics 111 measurements 59 poisson HPOisson 60 terminals used 25 wiring diagram 29 HBENding bending 1 2 bridge 59 HP IB address 21 group execute trigger GET 96 interface card 21 primary address 21 secondary address 21 HPOisson poisson 1 2 bridge 60 ID Register address space 123 126 device class 123 126 FET multiplexer 126 manufacturer identification 124 127 reading the 133 relay multiplexer 123 Identifying Terminal Module 14 IDN 98 Implied Commands 66 INITiate Subsystem 75 76 99 INITiate CONTinuous 75 INITiate CONTinuous 76 INITiate IMMediate 76 Instrument Addressing 21 Interface Select Code 21 Internal half bridge voltage diagn
23. 4 Chapter 4 Understanding the Strain Gage Multiplexers 49 The unstrained reference measurement is made because of the unbalanced bridge method of strain measurement Instead of balancing nulling the bridge before each measurement an unstrained reference Vout Vs unstrained is measured for each channel The unbalanced bridge measurement technique is described in the next section 3 Add tension to the specimen 4 Configure the multimeter and make the strain measurement s MEASure STRain strain_function channel_list or CONFigure STRain strain function Qchannel list When MEASure is used the multimeter is configured and the measurement is immediately taken Because of this variations to the multimeter configuration range aperture time are limited to the values set by the MEASure command see the table on page 77 When CONFigure is used the multimeter is configured but the measurement is not taken until READ or INIT is executed Thus low level multimeter commands covered in the multimeter manual can be used to change the configuration range aperture time before the measurement is made Note The strain measurement commands identified in this procedure are HP E1326B E1411B Multimeter commands Information on how these commands relate to strain measurements and how the multimeter makes strain measurements is contained in this manual Information on the entire multimeter command set and on general multimeter o
24. Bridge Arrangements 30 Connecting Strain Gages to the Multiplexers Chapter 2 Connecting Relay Strain Gage Multiplexers to an External Voltmeter HP E1300A E1301A Mainframe HP 1345 66201 A e O 2009 f WARNING 32 7 e e I HP E1355 E1356 00000000000 oo off MEER 2 000000000000 Se Bridge Wiring oooocoocoogooco9d 9 oco oc e E 00000 0 Le ss 9 o ee Iss HP 3458 Multimeter Oo O O i eO i ajo ola Figure 2 7 Connecting Relay Strain Gage Multiplexers to an External Voltmeter E1355A Fig2 7 Chapter 2 Connecting Strain Gages to the Multiplexers 31 Connecting FET Strain Gage Multiplexers to an External Voltmeter HP E1300A E1301A Mainframe z p elo HP E1351 66201 amy HP E1411 80001 H Cable Assembly HP E1357 E1358 Bridge WiringX 000000000 Channel YT hava nce
25. Bridge measurements FBPoisson Bending Poisson Full Bridge measurements QTENSsion Tension shunt diagnostic QCOMpression Compression shunt diagnostic UNSTrained Unstrain reference voltage measurement The default strain_function is QUARter bridge measurements QTENsion and QCOMpression are used for relay strain gage multiplexers only Example Making 4 Bridge Strain Measurements STR GFAC 2 11E 6 100 103 Specify the gage factors for the channels CAL STR 100 103 Measure the unstrained references MEAS STR QUAR 100 103 Configure the multimeter and make V4 bridge measurements 78 Strain Gage Multiplexer Command Reference Chapter 5 OUTPut Subsystem Syntax STATe Parameters Comments Example STATe Example The OUTPut subsystem enables or disables the Trig Out port of the HP E1300 E1301 Mainframe OUTPut STATe lt state gt STATe OUTPut STATe state enables disables the Trig Out port on the rear panel of the HP E1300 E1301 Mainframe OUTPut STATe ON 1 enables the port and OUTPut STATe OFF 0 disables the port Parameter Name Parameter Type Range of Values state Boolean 0 1 ON OFF Downloaded FET Multiplexer Scans The OUTPut subsystem does not work with downloaded FET multiplexer scan lists Downloaded scan lists are for use with the digital bus OUTPut works with all other scanning modes Enabling Trig Out Port When enabled the
26. Chassis 120V dc or AC RMS 170V peak Maximum Current per Channel 50 mA non inductive Maximum Power per Channel 1VA Thermal Offset per Channel 4 uV differential High to Low Closed Channel Resistance 1000 10 the value of the protection resistor Input Impedance Insulation Resistance Between any two points gt 10 Q at 40 C 65 RH Closed Channel Capacitance 10 kHz High to Low lt 150 pf Low to Guard lt 150 pf Guard to Chassis lt 2000 pf Relay Life No Load 10 G Rated Load 10 Operations Bandwidth 3 dB Z source Z load 500 Protec tion resistors shorted gt 10 MHz Channel Channel Crosstalk Watts Slot 1 Typical S0Q Source amp Load 1 kHz 80dB Cooling Slot 10 kHz 80 dB 0 02 mm H20 0 10 liter sec 100 kHz 80 dB 1 MHz 60 dB T 10 MHz 40 dB Humidity 65 0 to 40 C Protection resistors shorted and Low and Guard tied to chassis Operating Temperature 0 to 55 C Screw Terminal Wire Size 16 AWG Max 26 AWG Min Storage Temperature 40 to 75 C Module Size Device Type B register based EMC RFI Safety meets FTZ 1046 1984 CSA 556B Connectors Used P1 TEC 348 UE 1244 Number of Slots 1 Net Weight kg 0 9 VXIbus Interface Capability Interrupter D16 Interrupt Level 1 7 selectable Power Requirements Voltage 5V 412V Peak module current IPM A 0 53 0 13 Dynamic module current IDM A 0 01 0 01 Stra
27. Ground see The Wagner Ground on page 57 The Wagner Ground drives the midpoint of the bridge to the same potential as the specimen thus preventing stray leakage currents from affecting measurement accuracy Note that the shield must be connected to the specimen and not the gage Twisting the conductor leads reduces the loop area formed by the Wheatstone Bridge arms which may be exposed to magnetic fields which can degrade measurement accuracy Another factor to consider is wire gage since leadwire resistance can affect measurement accuracy when long cable runs are involved The effects of leadwire resistance can be predicted and corrected for by using the wire resistance table in Appendix B and the Leadwire Resistance Diagnostic on page 108 Chapter 2 Connecting Strain Gages to the Multiplexers 27 1 4 Bridge Diagrams 1 4 BRIDGE USING CHANNELS 0 3 USING CHANNELS 4 7 L
28. MIN MAX Parameter Type Range of Values Numeric MIN 1 MAX 32767 e Related Commands INITiate IMMediate Query Number of Scanning Cycles ARM COUN 10 ARM COUN Sets 10 scanning cycles Query number of scanning cycles returned value is 10 Chapter 5 Strain Gage Multiplexer Command Reference 69 CALibration The CALibration command subsystem is an HP E1326B E1411B Multimeter subsystem used to measure the unstrained reference voltage for each channel on which strain is measured Refer to Chapter 5 in the HP E1326B EI411B User s Manual for more information on the CALibration subsystem Subsystem Syntax CALibration STRain channel list STRain cCaLibration STRain channel list measures the unstrained reference voltage on the channels specified Parameters Parameter Name Parameter Type Range of Values channel list Numeric 00 07 Comments e The unstrained reference that is measured is the bridge output voltage Vout and the bridge excitation voltage Vs under unstrained conditions The reference is then computed as Vout Vs unstrained One unstrained reference is required for each channel on which strain 1s measured CALibration STRain is equivalent to executing CONFigure STRain UNSTrained followed by INIT Thus it leaves the multimeter configured for unstrained reference voltage measurements MEASure or CONFigure must be executed to configure the
29. Messages 137 HP E1355A 56A 57A 58A Modules User s Manual Contents 5 Notes 6 HP E1355A 56A 57 A 58A Modules User s Manual Contents Certification Hewlett Packard Company certifies that this product met its published specifications at the time of shipment from the factory Hewlett Packard further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Tech nology formerly National Bureau of Standards to the extent allowed by that organization s calibration facility and to the calibration facilities of other International Standards Organization members Warranty This Hewlett Packard product is warranted against defects in materials and workmanship for a period of three years from date of ship ment Duration and conditions of warranty for this product may be superseded when the product is integrated into becomes a part of other HP products During the warranty period Hewlett Packard Company will at its option either repair or replace products which prove to be defective For warranty service or repair this product must be returned to a service facility designated by Hewlett Packard HP Buyer shall pre pay shipping charges to HP and HP shall pay shipping charges to return the product to Buyer However Buyer shall pay all shipping charges duties and taxes for products returned to HP from another country HP warrants that its software
30. RST Condition All channels open Chapter 5 Strain Gage Multiplexer Command Reference 83 Example Scanning Using External Devices The following segments show how relay and FET strain gage multiplexer switchboxes are configured for strain measurements using an external multimeter HP 3458A Chapter 3 contains complete examples of making strain measurements using these configurations Relay Multiplexer Switchbox see Figure 2 7 on page 31 for external connections OUTP ON TRIG SOUR EXT SCAN PORT ABUS SCAN 100 102 115 INIT Enables the E1300 E1301 mainframe Trig Out port to output a signal when a channel is closed Set the switchbox to be externally triggered through the mainframe Event In port Connect the analog bus to the HI LO and Guard terminals on the terminal module Specify the multiplexer channel list to scan and measure Close the first channel in the scan list and start the scan FET Multiplexer Switchbox see Figure 2 8 on page 32 for external connections TRIG SOUR DBUS SCAN MODE VOLT SCAN PORT ABUS SETT TIME MAX 100 SCAN 100 102 115 INIT Switchbox is triggered over the digital bus Closes the tree switches required to make a voltage bridge output measurement Connect the analog bus to the HI LO and Guard terminals on the terminal module Set the delay between the external trigger and the channel closed signal Specify the multiplexer cha
31. already known or that have been previously measured and stored in a computer This is used in applications where it is not possible to make the unstrained reference measurement just prior to the strain measurement The unstrained reference is measured using CALibration STRain measured Downloading the Unstrained Reference One unstrained reference must be specified for each channel OUTPUT 70903 STR UNST Unstr 100 Downloads the reference from computer variable Unstr to channel 100 SENSe STRain UNSTrained channel list returns the unstrained references for the channels specified Parameter Name Parameter Type Range of Values channel_list Numeric 00 07 e The unstrained references are measured using CALibration STRain When queried the unstrained references are returned to the multimeter output buffer where they are then entered into a computer e One unstrained reference is required per channel Querying the Unstrained References CAL STR 100 102 STR UNST 100 102 ENTER variable Measures the unstrained references for channels 100 102 Queries the unstrained references for channels 100 102 Enter readings into the computer 90 Strain Gage Multiplexer Command Reference Chapter 5 STATus Subsystem Syntax OPERation ENABle Parameters Comments Example OPERation EVENt Comments Example The STATus subsystem reports the bit v
32. and an example which measures strains 1 2 and 3 is contained in Chapter 3 1 p 7 5 1 t 3 9 E1 3 Qe2 3 E 1 8 amp 3 1 Opq7 5 i ve 3 Qe2 amp 1 paT Ivy I v 1 2 2 1 3 N 1 3 Op q gt TA ta 73 8i e2 e3 121182 e2 3 3 1 opami ETE e e ce eae e ENT v v N3 2 3 281 2 3 Op q TAN where p q Principal strains Op q Principal stresses and Op q the acute angle from the axis of gage 1 to the nearest principal axis When positive the direction is the same as that of the gage numbering and when negative opposite NOTE Corrections may be necessary for transverse sensitivity refer to gage manufacturers literature The following equations relate stress to strain for a biaxial stress state Stress strain relationships are described in detail in Hewlett Packard s Application Note 290 1 Practical Strain Gage Measurements Ox Oy VE NE Oy O V x Ox 7 Ex V y 0 0 Appendix B Strain Gage Equations and Material Tables 105 Material Tables Table B 1 Wire Resistance solid copper wire AWG Ohms Foot 25 C Diameter in 18 0 0065 0 040 20 0 0104 0 032 22 0 0165 0 0253 24 0 0262 0 0201 26 0 0416 0 0159 28 0 0662 0 0126 30 0 105 0 010 32 0 167 0 008 Table B 2 Average Properties of Selected Engineering
33. and firmware designated by HP for use with a product will execute its programming instructions when properly installed on that product HP does not warrant that the operation of the product or software or firmware will be uninterrupted or error free Limitation Of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer Buyer supplied prod ucts or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or im proper site preparation or maintenance The design and implementation of any circuit on this product is the sole responsibility of the Buyer HP does not warrant the Buyer s circuitry or malfunctions of HP products that result from the Buyer s circuitry In addition HP does not warrant any damage that oc curs as a result of the Buyer s circuit or any defects that result from Buyer supplied products NO OTHER WARRANTY IS EXPRESSED OR IMPLIED HP SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND HTNESS FOR A PARTICULAR PURPOSE Exclusive Remedies THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES HP SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CON TRACT TORT OR ANY OTHER LEGAL THEORY Notice The information contained in this document is subject to change without notice HEWLETT PACKARD HP MAKES NO WAR R
34. are made using a FET strain gage multiplexer switchbox and an external HP 3458A voltmeter Dimension a computer variables to store the readings DIM Vout unstr 1 3 Vout str 1 3 Vr 1 3 Epsilon 1 3 Clear and reset the external multimeter CLEAR 722 OUTPUT 722 RESET Configure the external multimeter for DC voltage measurements Configure its trigger system such that the multimeter is externally triggered when the Imultiplexer channel is closed and so that it outputs a trigger signal when the measurement is complete to trigger the multiplexer OUTPUT 722 PRESET NORM OUTPUT 722 MEM FIFO OUTPUT 722 TBUFFON OUTPUT 722 TRIG EXT OUTPUT 722 EXTOUT RCOMP NEG Configure the FET multiplexer switchbox so that a channel is closed when a trigger is received via the digital bus Close the multiplexer tree relays necessary to make a DC voltage measurement Connect the analog bus which carries the bridge output and excitation voltages to the HI LO and Guard terminals on the multiplexer terminal module Set a delay between when the trigger to close a channel is received and when the channel closed trigger is generated This prevents voltmeter triggers from occurring too fast OUTPUT 70914 RST OUTPUT 70914 TRIG SOUR DBUS OUTPUT 70914 SCAN MODE VOLT OUTPUT 70914 SCAN PORT ABUS OUTPUT 70914 SETT TIM MAX 100 Download the scan list to measure Vout and Vs unstrained OUTPUT 70914 SCAN 100 102 1
35. avena v 2Vr 1 HBENding bending Fudge ES WCE FBENding Poisson Full Bridge 2VUGF v 1 Vrtv D EON e strain For results in microstrain multiply the calculated measured strain by 1E 6 NOTE tensile strain is compressive strain is Vr Vout VS strained Vout VS unstrained Vout bridge output voltage Vs bridge excitation voltage GF Gage Factor v Poisson Ratio Strain Gage Multiplexer Block Diagrams The manner in which strain related signals are routed from the specimen to the multimeter is illustrated with the block diagrams in Figure 4 1 Figure 4 1 Strain Gage Multiplexer Block Diagrams 52 Understanding the Strain Gage Multiplexers Chapter 4 Block Diag ram frForall strain measurements the bridge configuration is wired from the Desc ription specimen to selected E EI E2 H L and G terminals on the strain gage multiplexer terminal module When a strain measurement command is executed the bridge completion channel s relay or FET switch is closed as is the multiplexer s tree relay or tree switch This passes the H L and G signals from the strain gage to the multimeter via the analog bus The E El and E2 signals are wired directly to the strain gage measurement circuitry on the terminal module The measurement circuitry is covered in the following sections Understanding the Strain Gage Measurement Circuits This section d
36. bridge excitation voltage Vs Set Up Ifthe bridge excitation voltage is externally supplied connect the supply to the terminal module as shown in Figure C 1 Set the voltage to 5 0V If the bridge excitation voltage is internally supplied ensure the jumpers on the multiplexer component assembly are set correctly Chapter 1 Procedure Measure the bridge excitation voltage on internal channel 15 MEASure VOLT DC 115 The following example measures the bridge excitation voltage The program assumes the excitation voltage is externally supplied and that the strain gage multiplexer is used with the HP E1326B E1411B Multimeter as part of a scanning multimeter instrument The computer syntax used is HP BASIC running on a Hewlett Packard Series 300 computer Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Measure the bridge excitation voltage on internal channel 15 OUTPUT 70903 MEAS VOLT DC 115 ENTER 70903 Excit_volt Print the bridge excitation voltage PRINT Excitation voltage Excit_volt END A typical output from this program is Excitation voltage 5 0519 When measuring the internally supplied excitation voltage on the FET multiplexers the voltage is typically 4 6V 118 Strain Gage Diagnostics Appendix C Appendix D Strain Gage Register Based Programming About This Appendix Note The HP E1355A HP E1358A Relay and FET Strain Gage Multiplexers are register based modules
37. command returns 8 Channel FET Strain Gage 350 Ohms SYST CDES 1 Determine the description 92 Strain Gage Multiplexer Command Reference Chapter 5 CPON SYSTem CPON number ALL opens all channels of a selected multiplexer or all channels of all multiplexers in a switchbox Parameters Parameter Name Parameter Type Range of Values number Numeric 1to 99 ALL Comments Differences between RST and CPON SYSTem CPON opens all channels of a selected multiplexer or all channels of all multiplexers in a switchbox RST opens all channels of all multiplexers and sets all other multiplexer parameters to the power on state Example Opening all Channels on Multiplexer 1 SYST CPON 1 Opens all channels on multiplexer 7 CTYPe sYvsTem CTYPe number returns the type of multiplexer in a switchbox Parameters Parameter Name Parameter Type Range of Values number Numeric 1 to 99 Comments e 8 Channel 1200 Relay Strain Gage Multiplexer Module Model Number The SYSTem CTYPe number command returns HEWLETT PACKARD E1355A 0 A 03 00 8 Channel 3500 Relay Strain Gage Multiplexer Module Model Number The SYSTem CTYPe number command returns HEWLETT PACKARD E1356A 0 A 03 00 8 Channel 1200 FET Strain Gage Multiplexer Module Model Number The SYSTem CTYPe number command returns HEWLETT PACKARD E1357A 0 A 03 00 8 Channel 3500 FET Strain Gage Multiplex
38. connect the strain gages to the bridge completion channels BRIDGE EXCITATION VOLTAGE TERMINALS o H L GTH L GTH L G O o0000000000000000000 000000000000 00000000000000000000000000000000 G LH G L HTG LH OM O OuMs O Ome O H L G ARO e SIS LE Oise A R L H O2 O OM O Omo O H L G I 7V8s 7 TB 1 d 1 4 1 2 1 1 o 1 4 1 2 l 00000000000 0 m 92909 o o oj ofoo S500 Blo 0000000000 o 181 ooo TB6 TB7 3 0000 i4 E 2 loooo oloooo O FULL H L 3 ru 9 O JM14 OJO JMI5 O O JM16 OJO um17 O gees nate O JM13 O O JM12 O OJM11 OJO JM10 O A a ea ke 3555 VQLTMETER Vs 3555 amp LoHOw A LA E BRIDGE BRIDGE CH4 CH5 CH6 CH7 Pd CH3 CH2 CH1 CHO O R42 O O R43 O O mo O O BrR21 O HE SELES PE SET SE2 E SEloSE2 1 EET EZ SEZ ET E TAEZ SET RE SER med SE DEN RI E 1 1 00000000000 000000000 0 oo TB2 COMMON HLG TBS ole o lee ge o o o o TERMINALS o ofs o oj o o eo R RS f 7382 T5 f VR RO BRIDGE SELECTION E1355 2 1 JUMPERS esp BRIDGE 1 4 1 2 ooo COMPLETION POSITION vc CHANNELS Figure 2 1A Terminal Module Configuration Chapter 2 Connecting Strain Gages to the Multiplexers 23 WARNING To prevent shock use only wire rated for L highest input voltage and disconnect all field power before removing cover or terminal assembly Voltmeter Excitation
39. factor for the channel measured OUTPUT 70903 STR GFAC 2 115E 6 107 Measure the channel s unstrained reference OUTPUT 70903 CAL STR 107 DISP Add tension to the specimen then press Continue PAUSE DISP n Measure the strain on the channel Enter and display the reading OUTPUT 70903 MEAS STR FBEN 107 ENTER 70903 Strn_rdg PRINT Strn rdg END Comments The wiring diagram used for this example FBENding is on page 30 When making full bridge measurements the channel s bridge selection jumper must be in the FULL position Specifying the gage factor as 2 1 15E 6 returns the strain measurements in microstrain A gage factor must be specified and an unstrained reference must be measured for each channel 40 Making Strain Gage Measurements Chapter 3 Relay Strain Gage Measurements with an External Voltmeter This program shows how strain measurements are made using a relay strain gage multiplexer switchbox and an external HP 3458A voltmeter Dimension computer variables to store the readings DIM Vout unstr 1 3 Vout str 1 3 Vr 1 3 Epsilon 1 3 Clear and reset the external multimeter CLEAR 722 OUTPUT 722 RESET Configure the external multimeter for DC voltage measurements Configure its trigger system such that the multimeter is externally triggered when the multiplexer channel is closed and so that it outputs a trigger signal when the measurement is complete to t
40. fold here NO POSTAGE NECESSARY IF MAILED IN THE UNITED STATES BUSINESS REPLY MAIL FIRST CLASS PERMIT NO 37 LOVELAND CO E POSTAGE WILL BE PAID BY ADDRESSEE ers HEWLETT PACKARD COMPANY Measurement Systems Division pA Learning Products Department P O Box 301 Loveland CO 80539 9984 Illl llnl llill lll dodo fold here Please pencil in one circle for each statement below Disagree X Agree e The documentation is well organized O O O O O e Instructions are easy to understand O O O O O e The documentation is clearly written O O O O O e Examples are clear and useful O O O O O e llustrations are clear and helpful O O O O O e The documentation meets my overall expectations O O O O O Please write any comments or suggestions below be specific 12 HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual Chapter 1 Getting Started with the Strain Gage Multiplexers About This Chapter This chapter describes the physical and functional characteristics of the HP E1355A E1356A E1357A and E1358A Strain Gage Multiplexers and explains how the multiplexers are prepared for use in a VXIbus system The sections of this chapter are e Strain Gage Multiplexer Overview Page 13 e Using the Multiplexers in a VXIbus System Page 14 Strain Gage Multiplexer Overview The strain gage multiplexers to
41. half bridge resistor V lower the bridge output voltage Vout e the voltage across the leadwire V leadwire e the 120 or 3509 bridge completion resistor Rcomp These parameters are represented with the circuit of Figure C 2 and the leadwire resistance is calculated using the equation R leadwire V leadwire x Rcomp V lower Vout V leadwire C 5 ACAD E1355 F_C_2 Figure C 2 Determining Leadwire Resistance Appendix C Strain Gage Diagnostics 109 1 Measure the voltage across the lower leg 1kQ internal half bridge resistor MEASure VOLT DC 110 2 Measure the bridge output voltage Vout on channel 0 This is a DC voltage measurement MEASure VOLT DC 100 3 Measure the voltage on the leadwires V leadwire for the strain gage on channel 0 or 1 MEASure VOLT DC 108 channel 0 MEASure VOLT DC 109 channel 1 4 Compute the value of leadwire resistance by substituting the voltages and bridge completion resistance 1204 or 350Q into the equation The following example determines the leadwire resistance on channel 0 The program assumes the strain gage multiplexer uses the HP E1326B E1411B Multimeter as part of a scanning multimeter instrument The computer syntax used is HP BASIC running on a Hewlett Packard Series 300 computer Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Measure the voltage across the lower leg of the internal Ya b
42. multimeter for a strain measurement Example Measuring the Unstrained Reference CAL STR 2100 Measures the unstrained reference on channel 0 70 Strain Gage Multiplexer Command Reference Chapter 5 CONFigure The CONFigure command subsystem is an HP E1326B E1411B Multimeter subsystem which configures the multimeter for strain measurements Unlike MEASure CONFigure does not make a measurement immediately after setting the configuration Thus CONFigure is used in applications where the multimeter configuration must be changed using lower level commands see below Executing CONFigure is equivalent to configuring the multimeter with the low level commands shown in the following table Aperture Time Integration Time Autozero Offset Compensation Trigger Source Number of Triggers or Number of Scans Trigger Delay Readings per Trigger Sample Period RESistance RESolution VOLTage APERture RESistance APERture VOLTage NPLC RESistance NPLC CALibration ZERO AUTO RESistance OCOMpensated Parameter Command Setting Range VOLTage RANGe As specified or autorange RESistance RANGe Resolution VOLTage RESolution As specified or as a function of range integration time or aperture time 16 7 ms 60 Hz or 20 ms 50 Hz or based on specified resolution 1 power line cycle PLC or based on specified resolution ON autozero is performed after every measurement OFF resistance me
43. one amp fuse HP part number 2110 0665 in place of the wire short When the relay multiplexers are shipped from the factory the jumpers are not installed Thus the excitation voltage must be externally supplied as explained in Chapter 2 18 Getting Started with the Strain Gage Multiplexers Chapter 1 FET Multiplexer Excitation Voltage CAUTION Strain Gage Multiplexer Configurations Creating a Scanning Multimeter Instrument The internal bridge excitation voltage for the HP E1357A E1358A FET strain gage multiplexers is 4 6V referenced to mainframe chassis and current limited at 450 mA The voltage is accessed as indicated by the movable jumper setting shown in Figure 1 4 When the FET multiplexers are shipped from the factory the jumper is in the ON position If the jumper is moved to the OFF position the excitation voltage must be externally supplied as explained in Chapter 2 If the bridge excitation voltage is externally supplied be sure that the jumper is not installed or with the FET multiplexers ensure that the STRAIN EXCITATION jumper is in the OFF position Otherwise unpredictable strain measurements may result In a B Size or C Size V XIbus system the strain gage multiplexers can be used in two configurations e Scanning Multimeter multiplexers are used with an HP E1326B E1411B Multimeter e Switchbox multiplexers are used with an external voltmeter Guidelines for creating a scanning m
44. scan list When this bit is set to zero 0 the last channel in the scan list generates an interrupt if the channel is valid VLD set true 0 Scan Channel Configuration Register Reset Pointer Resets the pointer back to the beginning of the scan list CNT EN true automatically resets the pointer at the end of the scan list The Scan Channel Delay Register sets the SETTling TIME the time between receipt of a channel closing trigger and the channel closed pulse The delay is 2 usec and has a range of 0 to 15 D3 to DO set base 0816 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined X X X X D3 D2 Di DO D3 DO Data bits three to zero These bits designate a number between 0 and 15 n for 130 Strain Gage Register Based Programming Appendix D Scan Channel These bits set the channel list for a scan list set the type of measurement Co nfigu ration and enable disable the Tree Isolation switches Note that the DIR in the Control Register must be set false to enable this register Register base OA16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write VID A DIBD C1 CO X X X X X X X D3 D2 Di DO D3 DO Databits three tozero The FET strain gage multiplexer channels and diagnostics are mapped into bits D3 through DO as follows D3 DO 0000 _ closes bridge completion channel 0 0001 c
45. the terminal module The bridge excitation voltage required for each bridge arrangement 1 4 Ya full and a recommended power supply are found in Table 2 1 Table 2 1 Bridge Excitation Voltage and Power Requirements V4 or 12 Bridge Arrangements Voltage Power 8 channels of 1200 bridge arrangements 5V 200 mA 1 0W 8 channels of 3500 bridge arrangements 5V 70 mA 0 35W Full Bridge Arrangements Voltage Power 8 channels of 1200 bridge arrangements 5V 400 mA 2 0W 8 channels of 3504 bridge arrangements 5V 0140 mA 0 7W PARD periodic and random deviation from DC value 1mVp p 20 Hz to 20 MHz Recommended Power Supply HP 6414C or equivalent 24 Connecting Strain Gages to the Multiplexers Chapter 2 Bridge Completion The strain gages mounted to the specimen are connected to the terminal Channels module bridge completion channels via the E E1 E2 H L and G terminals Each channel contains these six terminals in order to accommodate a 1 4 Y or full bridge arrangement A wire is connected to a terminal by 1 loosening the screw on the terminal 2 inserting the wire into the opening opposite the screw 3 tightening the screw to secure the wire in place Routing the wires under the strain relief clamp will prevent the wires from being pulled out of the terminal Bridge Wiring The 1 4 1 2 and full bridge wiring diagrams on the terminal module cover Diag rams Figur
46. the DIR bit in the Control Register must be set true Re g ister for this register to be enabled base 0C16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined X X X X D3 D2 D1 DO D3 DO Data bits three to zero The FET strain gage multiplexer channels and diagnostics are mapped into bits D3 through DO as follows D3 DO 0000 closes bridge completion channel 0 0001 closes bridge completion channel 1 0010 closes bridge completion channel 2 0011 closes bridge completion channel 3 0100 measures the leadwire resistance on bridge completion channel 0 0101 measures the leadwire resistance on bridge completion channel 1 0110 measures the lower leg of the internal half bridge voltage 0111 measures the upper leg of the internal half bridge voltage 1000 closes bridge completion channel 4 1001 closes bridge completion channel 5 1010 closes bridge completion channel 6 1011 closes bridge completion channel 7 1100 notused 1101 not used 1110 measures the guard voltage 1111 measures the bridge excitation voltage Direct Control The Direct Control Register allows you to set the controls for individual Reg ister channels Note that the DIR bit in the Control Register must be set true for this register to be enabled base 0E16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined x Xx X VIDAD BD C1 CO C1 CO Configuration bits These bits determine the measurement Mode as listed be
47. the number of cycles has not reached the ARM COUNt parameter returns to the beginning of the scan list and closes the first channel When the number of cycles equals the ARM COUNt parameter the scanning cycle stops Note that ARM COUNt does not apply to downloaded FET multiplexer scan lists Stopping Continuous Scans Continuous scanning can be stopped by the ABORt command for non downloaded scans and by a system reset or a power off for downloaded FET multiplexer scans Related Commands ABORt ARM COUNt RST TRIGger TRIGger SOURce e RST Condition INITiate CONTinuous OFF Example Enabling Continuous Scans INIT CONT ON Enables continuous scanning SCAN 100 107 Sets channel list INIT Starts scanning cycle Chapter 5 Strain Gage Multiplexer Command Reference 75 CONTinuous INiTiate CONTinuous queries the scanning state With continuous scanning enabled the command returns 1 With continuous scanning disabled the command returns O Example Query Continuous Scanning State INIT CONT ON Enables continuous scanning INIT CONT Query continuous scanning state IMMediate INITiate IMMediate starts the scanning cycle and closes the first channel in the channel list Successive triggers from the source specified by the TRIGger SOURce command advance the scan through the channel list Comments e Starting the Scanning Cycle The INITiate IMMediate command starts scanning by closing the first channel in the channel
48. which do not support the VXIbus word serial protocol When an SCPI command is sent to the multiplexer switchbox the HP E1300 E1301 Mainframe Series B or the HP E1405 E1406 Command Module Series C parses the command and programs the multiplexer at the register level When the strain gage multiplexers are used with the HP E1326B E1411B Multimeter which is also register based SCPI commands are parsed by the mainframe command module and are written to the multimeter registers Register based programming is a series of reads and writes directly to the multiplexer or multimeter registers This increases throughput speed since it eliminates command parsing and allows the use of an embedded controller Also if slot 0 the resource manager and the computer interface HP IB are provided by other devices a C size system can be downsized by removing the command module This appendix contains the information you need for register based programming The contents include e Register Addressing 0 0 cece eee eee Page 120 e Register Descriptions eee ee eee Page 123 e Relay Multiplexer Registers Page 123 e FET Multiplexer Registers llle 000 0000 Page 126 e Programming Examples 00 0 0 e eee eee Page 133 This appendix covers relay and FET multiplexer register based programming from a multiplexer switchbox standpoint Register based programming for scanning multimeter instruments multimeters and multiplexers in a singl
49. 00 computer over the HP IB When using HP BASIC a command is sent to the scanning multimeter instrument with the OUTPUT statement OUTPUT 70903 MEAS STR QUAR 100 The destination specified 70903 is the interface select code of the computer 7 plus the HP IB addresses of the HP 75000 Series B mainframe or Series C command module 09 plus the multimeter instrument address 03 The multimeter command is enclosed between quotation marks Data from the multimeter instrument is entered into the computer using the ENTER statement ENTER 70903 variable Chapter 3 Making Strain Gage Measurements 33 Note Except as noted each program in this chapter assumes the strain gage multiplexer relay and FET is used with the HP E1326B E1411B multimeter as part of a scanning multimeter instrument at secondary HP IB address 03 Connecting Strain Chapter 2 contains the wiring diagrams for connecting strain gages to the Gages multiplexer bridge completion channels Each example program indicates the wiring diagram used Strain Measurement Strain measurements with the strain gage multiplexers and HP E1326B Procedure EI411B multimeter are made as follows 1 Specify the Gage Factor and for Poisson configurations the Poisson Ratio 2 Measure the unstrained reference voltage Vout Vs unstrained 3 Add tension to the specimen 4 Configure the multimeter and make the strain measurement Vout Vs strained Each example in t
50. 134 reading the ID register 133 register addressing 120 register descriptions 123 relay multiplexer registers 123 125 resetting the switchbox 135 Registers addressing 120 channel 125 control 125 129 135 descriptions 123 device type 124 127 134 direct channel configuration 132 direct control 132 FET multiplexer 126 130 FET multiplexers READ 126 128 FET multiplexers WRITE 129 132 ID 123 126 133 offset 122 operation status 91 relay multiplexer 123 125 relay multiplexers READ 123 124 relay multiplexers WRITE 125 scan channel configuration 131 scan channel delay 128 130 scan control 128 130 status 91 124 127 tree switch 125 Relay life expectancy 103 replacement strategy 103 Relay Multiplexer channel register 125 closing tree switches 86 connecting to external voltmeter 31 control register 125 device type register 124 excitation voltage 18 ID register 123 identifying 14 measurements with an external voltmeter 41 opening tree switches 82 registers 123 125 status register 124 switchbox 84 tree switch register 125 tree switches 86 Resistance and Voltage Measurements 64 Rosette equations 105 measurements 58 measurements example program 39 ROUTe Subsystem 80 87 99 ROUTe CLOSe 80 ROUTe CLOSe 81 ROUTe OPEN 82 144 HP E1355A 56A 57A 58A Modules User s Manual Index ROUTe OPEN 82 ROUTe SCAN 83 84 ROUTe SCAN MODE 85 NONE 85 RES 85 VO
51. 15 OUTPUT 70914 INIT DISP Add tension to the specimen then press Continue PAUSE DISP n Download the scan list to measure Vout and Vs strained OUTPUT 70914 SCAN 100 102 115 OUTPUT 70914 INIT Compute and display the V4 bridge strain measurements ENTER 722 Vout unstr Vs unstr Vout str Vs str CALL Strn cmput Vr Vout str Vout unstr Vs str Vs unstr END SUB Strn cmput Vr Vout str Vout unstr Vs str Vs unstr FOR I 1 TO 3 Vr l Vout_str l Vs_str Vout_unstr l Vs_unstr Epsilon l 4 Vr 1 2 11E 6 1 2 Vr 1 PRINT Epsilon l NEXT SUBEND Chapter 3 Making Strain Gage Measurements 43 Comments The strain gage wiring diagram used for this example is on page 28 The diagram showing how the HP 3458A Multimeter is connected to the FET strain gage multiplexer is on page 32 When making strain measurements with an external voltmeter the following voltages are measured in the sequence shown bridge output voltage Vout channels 100 102 unstrained bridge excitation voltage Vs channel 115 unstrained bridge output voltage Vout channels 100 102 strained bridge excitation voltage Vs channel 115 strained These measurements are used to compute Vr which in equation form is defined as Vr z Vout V s strained Vout V s unstrained Vr is then substituted into the equation Table 4 1 on page 52 for V4 bridge measurements The channel closed measurement handsha
52. 244 Net Weight kg 0 9 102 HP E1355A E1356A E1357A E1358A Specifications Appendix A Relay Life End of Life Detection Replacement Strategy Note Electromechanical relays are subject to normal wear out Relay life depends on several factors The effects of loading and switching frequency are briefly discussed below Relay Load In general higher power switching reduces relay life In addition capacitive inductive loads and high inrush currents e g turning on a lamp or starting a motor reduces relay life Exceeding specified maximum inputs can cause catastrophic failure Switching Frequency Relay contacts heat up when switched As the switching frequency increases the contacts have less time to dissipate heat The resulting increase in contact temperature also reduces relay life A preventive maintenance routine can prevent problems caused by unexpected relay failure The end of the life of the relay can be determined by using one or more of the three methods described below The best method or combination of methods as well as the failure criteria depends on the application in which the relay is used Contact Resistance As the relay begins to wear out its contact resistance increases When the resistance exceeds a predetermined value the relay should be replaced Stability of Contact Resistance The stability of the contact resistance decreases with age Using this method the contact resistance is mea
53. 6 1C0016 1FDC0016 or 2 080 768 112 64 2 080 768 7 168 2 087 936 The register offset is the register s location in the block of 64 address bytes For example with a LADDR of 112 the multiplexer s Scan Channel Delay Register has an offset of 0816 When you write a command to this register the offset is added to the base address to form the register address DC0016 0816 DC0816 A16 outside the command module 1FDC0016 0816 1FDC0816 A16 inside the command module or 56 320 8 56 328 A16 outside the command module 2 087 936 8 2 087 944 A16 inside the command module 122 Strain Gage Register Based Programming Appendix D Register Descriptions Relay Multiplexer The READ Registers ID Register This section describes the relay strain gage multiplexer and FET strain gage multiplexer registers Registers There are three READ and three WRITE registers on the relay strain gage multiplexers The following READ registers are located on the relay strain gage multiplexer D Register base 0016 Device Type Register base 0216 e Status Register base 0416 The relay multiplexer s ID Register indicates the classification addressing mode and the manufacturer of the device base 0016 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Class Mode Read Device Address Manufacturer ID Device Class Address Space Device Cla
54. 64 with downloaded unstrained references 46 47 with external voltmeter 41 43 45 Multi Channel Quarter Bridge Measurements 36 Multimeter logical address 19 20 making strain measurements 135 making strain measurements with 49 Multiple SCPI commands linking 67 Multiplexer 120 ohm 55 350 ohm 55 card numbers 21 channel address 22 connecting 22 connecting to strain gages 23 32 34 logical address 19 20 register based programming 119 136 specifications 101 104 type in switchbox 93 N Noise Induced Currents 27 Numeric Command Parameters 67 O OPC 98 OPC 98 Opening chamnels 82 93 tree switches 82 Operation Status Register 91 bit value 91 Optional command parameters 67 commands 66 OUTPut Subsystem 79 99 OUTPut STATe 79 OUTPut STATe 79 Overview 13 P Parameters 67 Physical Description 13 Poisson bending full bridge FBPoisson 62 full bridge measurements FPOisson 63 half bridge measurements HPOisson 60 ratio 89 Power Requirements 24 Primary HP IB Address 21 Program Examples dynamic strain measurements 37 See also Examples FET multiplexer scanning 135 FET strain gage measurements 43 45 language used 33 measurements using external voltmeter 41 43 45 measurements with downloaded unstrained references 46 47 measuring bridge excitation voltage 135 multi channel 1 4 bridge measurements 36 reading the device type register 134 re
55. ANTY OF ANY KIND WITH REGARD TO THIS MATERIAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WAR RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE HP shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material This docu ment contains proprietary information which is protected by copyright All rights are reserved No part of this document may be photo copied reproduced or translated to another language without the prior written consent of Hewlett Packard Company HP assumes no responsibility for the use or reliability of its software on equipment that is not furnished by HP Restricted Rights Legend Use duplication or disclosure by the U S Government is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause in DFARS 252 227 7013 Hewlett Packard Company 3000 Hanover Street Palo Alto California 94304 U S A Rights for non DOD U S Government Departments and Agencies are as set forth in FAR 52 227 19 c 1 2 D HEWLETT PACKARAL HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual Edition 3 Copyright 1995 Hewlett Packard Company All Rights Reserved HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual 7 Documentation History All Editions and Updates of this manual and their creation date are listed below
56. Contents HP E1355A 56A 57A 58A Modules User s Manual WINES rrr te TE Qk Ew aE bh he we Ge we SOK Kw RE 4 E WARNI 2 aa LEER EE A a EA AAA 8 ds 44k 4 kd F4 ee E dub ESL EHS ES PEE 8 Declaration oT CORFODIDE a e di e ope od e Re E Rok ed Be OR 9 R ider Comment Simmel idos aaa uo E Boe Bk OO ed d 11 Chapter 1 Getting Started with the Strain Gage Multiplexers 13 About This Chapter e a RA A dd e 13 Strain Gage Multiplexer Overview o eee ee ee ee 13 Physical Descip rlil 4 9 sux dos R eRe en e DEERE EAE EAERS EES 13 Fimetonal Desciphon a se gu ap pekoak d do pe ok A ee e ed oed 13 Using the Multiplexers ina VXIbus System o o 0200004 14 Identifying the Terminal Module 14 Sens me Cad ID SWIC oo a ER a we OEC aS Ew Ge A 16 Selecting the Interrupt Line Number ec ao aoo de Ro he e ew RO 17 Internally Supplied Bridge Excitation Voltage o o 18 Strain Gage Multiplexer Configurations gt e s lt ei o o e 19 Insteaient AC MSSIDE uiuo a AAS koh eee RA ceo s 21 Connecting the Multiplexers 1 445454 s Rok be EERE ERE ERES 42 Chapter 2 Connecting Strain Gages to the Multiplexers 23 About This CHAPEL ss dcs eke RES Bock RO EE RAS a ES 23 Terminal Module Configuration lee 23 Bridge Selection Jupeis 4e mo SRR EO HSER EO OR RAE RE WAS 24 Bridge Excitation Voltage Terminals se sec Re RR OR adti tk 24 Bridge Completion Channels cs rk R 444440 d 28 B
57. E 7 ER VS EXTERNAL EXCITATION VOLTAGE aly 4 1 4 1 2 pp OUT Z BOTTOM SPECIMEN 1262 P j 35a gt SZ We INTERNAL HALF BRIDGE TERMINAL MODULE COMPONENT MODULE e1355 fig4 5 Figure 4 5 Bridge Completion Circuitry Full Bridge 1200 and 3500 A 1200 strain gage multiplexer is distinguished from a 350Q multiplexer Multiplexers by the value of the Wheatstone bridge completion resistor shown in Figure 4 3 When strain is measured with a 4 bridge arrangement a 1200 strain gage multiplexer is required for 120Q gages and a 3500 multiplexer is required for 350 gages In the 1 2 and full bridge arrangements the bridge completion resistor is replaced by a strain gage Figures 4 4 4 5 Thus any strain gage multiplexer can be used with any value of gage resistance when measuring strain with a 4 or full bridge arrangement Chapter 4 Understanding the Strain Gage Multiplexers 55 The Chevron Bridge When measuring strain with Y4 and Y bridge arrangements the strain gage accessories use a variation of the Wheatstone Bridge known as the Chevron Bridge Figure 4 6 The V4 bridge and Y bridge arrangements still complete the Wheatstone Bridge however the Chevron Bridge enables the bridge exci
58. E Base_addr 10 16 H6001 OUTPUT 70900 DIAG POKE Base_addr 10 16 H6002 OUTPUT 70900 DIAG POKE Base_addr 10 16 H600F Set the settling time from when the channel advance pulse is received l until the channel closed pulse is generated 32 768 msec OUTPUT 70900 DIAG POKE Base_addr 8 16 HF Set the switchbox to be externally triggered OUTPUT 70900 DIAG POKE Base_addr 6 16 H02 Initiate the scan by closing the first channel in the list OUTPUT 70900 DIAG POKE Base_addr 4 16 H10 SUBEND Subprogram which computes the measured strain SUB Strn cmput Vr Vout str Vout unstr Vs str Vs unstr FOR I 1 TO 3 Vr I 2Vout str l Vs str Vout unstr l Vs unstr Epsilon I 2 4 Vr I 2 11E 6 1 2 Vr l PRINT Epsilon l NEXT I SUBEND 136 Strain Gage Register Based Programming Appendix D Appendix E Strain Gage Multiplexer Error Messages Table E 1 lists the error messages associated with the strain gage multiplexer modules programmed by SCPI See mainframe manual for a complete list Table E 1 Strain Gage Multiplexer Error Messages No Title Potential Cause s 211 Trigger ignored Trigger received when scan not enabled Trigger received after scan complete Trigger too fast 213 Init ignored Attempting to execute an INIT command when a scan is already in progress 224 Illegal parameter value Attempting to execute a command with a parameter not a
59. E B G L H H L C E CES S E S p p E20 G o l 1 4 Bridge 1 4 1 2 OI oo le SIS 0000 FULL Re G SHIELD SHIELD QUARTer ROSETTE CHANNEL 2 CHANNEL CHANNEL 0 ESH G L H G L H G L H EH aL o ES S E i E E E S E E SEZ O Q9 1 4 Bridge 1 4 1 2 doll ONO O O O O Qo SESS espe E ZA Sa O T en p v SHIELD knee Figure 2 4 Connecting Strain Gages in 1 4 Bridge Arrangements 28 Connecting Strain Gages to the Multiplexers Chapter 2 1 2 Bridge Diagrams SING CHANNELS 0 3 JESH G L H G L H Elo L o IS S e el l e E29 G ey 1 2 Bridge 1 4 1 2 APE ollollallo al a 5 CURE E2 E EE FULL AE i Bottom e C shield e ES Poisson 1 2 Bridge HPOisson Bending 1 2 Bridge USING CHANNELS 4 7 H L G H LC IS A e ie l Ie SA NY E m ej l l l S S IS XE SENS amp E ET ES
60. Figure 4 13 Full Bridge Arrangement Bending Full Bridge The maximum sensitivity achieved with a full bridge arrangement is when FBENding the strain gages are mounted to the specimen as indicated in Figure 4 14 When the beam is strained gages Rgl and Rg are strained in tension and gages Rg3 and Rg4 are strained in compression When all gages are strained the same amount simultaneously the bridge sensitivity is increased by a factor of four Since the gages undergoing tensile and compressive strain are adjacent legs in the Wheatstone Bridge circuit any temperature induced strain is cancelled tension TA ESS compression Rg4 E Rgj E1355 fig4 14 Figure 4 14 Bending Full Bridge Chapter 4 Understanding the Strain Gage Multiplexers 61 Bending Poisson Full In applications where there is no equal strain of opposite sign as there is for Bridge FBPoisson he beam in Figure 4 14 Poisson strain can be measured by mounting the strain gages at right angles on the specimen Mounting the gages in this manner is known as a Poisson arrangement and is represented in Figure 4 15 With a Poisson arrangement the sensitivity is not as great as with the bending full bridge However since the gages are adjacent legs of the Wheatstone Bridge circuit complete temperature compensation is achieved
61. ISson 89 SENSe STRain UNSTrained 90 SENSe STRain UNSTrained 90 Setting card ID switch 16 logical address 19 21 settling time 87 status register bit 7 91 Shunt Verification compression 113 diagnostics 113 tension 113 Single Channel bending full bridge measurements 40 quarter bridge measurements 35 Specifications 101 104 SRE 98 SRE 98 Standard Commands for Programmable Instruments See SCPI Commands Status Register 91 FET multiplexer 127 relay multiplexer 124 STATus Subsystem 91 99 STATus OPERation ENABle 91 STATus OPERation EVENt 91 STB 98 Strain Gage Measurement Circuits Chevron Bridge 56 understanding 53 Wagner Ground 57 Wheatstone Bridge 54 55 Strain Gage Multiplexer HP E1355A 56A 57A 58A Modules User s Manual Index 145 block diagrams 52 card numbers 21 channel address 22 command reference 65 100 configurations 19 connecting 22 32 34 connecting bridge completion channels 27 diagnostics 107 118 error messages 137 138 getting started 13 22 logical address 19 21 making measurements 33 48 measurement circuits 53 See also multiplexer overview 13 strain measurement procedure 34 understanding the 49 64 using in VXIbus system 14 wiring diagrams 27 32 Strain Measurement equations 52 105 gage factor 88 making 49 poisson ratio 89 procedure 49 unstrained references 70 using multimeter 135 Switchbox 19 card numbers 21 continuous
62. LT 85 ROUTe SCAN MODE 85 ROUTe SCAN PORT 86 ABUS 86 NONE 86 ROUTe SCAN PORT 86 ROUTe SETTling TIME 87 ROUTe SETTling TIME 87 RST 98 100 S Safety warnings 8 SAV 98 Scan Channel Configuration Register FET multiplexer 131 Scan Channel Delay Register FET multiplexer 128 130 Scan Control Register FET multiplexer 128 130 Scanning continuous cycles 75 cycle starting 76 cycles ARM 69 cycles continuous 75 FET multiplexer 135 query state 76 using bus triggers 97 using external devices 84 using external triggers 96 Scanning Multimeter 19 card numbers 21 creating 19 20 logical address 19 21 Scanning Voltmeter continuous scanning 75 SCPI Commands 65 abbreviated 66 ABORt 68 99 ARM subsystem 69 99 CALibration subsystem 70 99 CONFigure subsystem 71 72 99 DIAGnostic PEEK 133 DIAGnostic POKE 133 DISPlay subsystem 73 74 99 format used 65 implied 66 INITiate subsystem 75 76 99 linking 67 long form 66 MEASure subsystem 77 78 99 optional 66 optional parameters 67 OUTPut subsystem 79 99 parameters 67 quick reference 99 reference 67 99 ROUTE subsystem 80 87 99 SENSe subsystem 88 90 90 short form 66 STATus subsystem 91 99 SYSTem subsystem 92 94 99 TRIGger subsystem 95 97 100 Secondary HP IB Address 21 SENSe Subsystem 88 90 99 SENSe STRain GFACtor 88 SENSe STRain GFACtor 89 SENSe STRain POISson 89 SENSe STRain PO
63. Materials exact values may vary widely Modulus of Elastic Strength Material Poisson s Ratio v Elasticity Tension psi E psi x 10 ABS unfilled 0 2 0 4 4500 7500 Aluminum 2024 T4 0 32 10 6 48000 Aluminum 7075 T6 0 32 10 4 72000 Red Brass soft 0 33 15 15000 Iron Gray Cast 13 14 Polycarbonate 0 285 0 3 0 38 8000 9500 Steel 1018 0 285 30 32000 Steel 4130 4340 0 28 0 29 30 45000 Steel 304 SS 0 25 28 35000 Steel 410 SS 0 27 0 29 29 40000 Titanium alloy 0 34 14 135000 2 Elastic strength may be represented by proportional limit yield point or yield strength at 0 2 percent offset 106 Strain Gage Equations and Material Tables Appendix B Appendix C Strain Gage Diagnostics About This Appendix This appendix covers the diagnostics associated with the strain gage multiplexers The diagnostics check configuration integrity and increase measurement accuracy The diagnostics in this appendix include e Leadwire Resistance 0 0 0 eee eee eee eee Page 108 e Internal Half Bridge Voltage Page 111 e Shunt Verification 2 0 eee eee eee ee eee Page 113 e Guard Voltage eigo a pe aa Page 116 e Bridge Excitation Voltage 00 00 02 ee eee Page 118 Diag nostic The multiplexer diagnostics are accessed through internal channels as Channels well as the external bridge completion channels Table C 1 identifie
64. RUE EGRE 49 Makine Strain Measurements uu ld xh RO ORAE OEC OX EO Re we XC 49 Stain Measurement PrOCEdUIE s uoi eati es eee A ES RES OS 49 Unbalanced Bridge Measurement Technique 0 50 Downloaded Unstrained References bc ee ee 51 Stam Measurement EQUIDORS a 2 eka GA as e REOR UR oe eRe 52 Strain Gage Multiplexer Block Diagrams gt e o oac o o e 32 Block Diagram Description o m eR m OE RO RR RRR HERS 53 Understanding the Strain Gage Measurement Circuits o o 23 The Wheatstone Bridge usos doa o 4 CE eo RR OR ORTU Ree e ed 54 Thel hevro Bridge iu sdb wRRG e CEN GR eq dox ded 56 THe XY aper Ol 24 26 24 PUR ROR EON AAA Ce a TN 57 Understanding the Bridge Configurations sas lt a llle 58 1 4 Bridge Measurements QUARter 2 000002 ee eee 58 1 2 Bridge Measurements e EORR Ob eR RK A a 59 Full Bridas Messutembnls i a crr rreperi 56644454 5 Robe EO 4 61 Measurements Using an External Voltmeter llle 63 DOLU X augxd 554340 ERROR GE b cA Noo web EEG LEE BERS 63 l ria RR odo ESSE EERE EERE V 63 Voltage and Resistance Measurements Luka koh wx RA A E 64 Chapter 5 Strain Gage Multiplexer Command Reference 65 About This COPIE 4 uo EEO E SEEPS EE due ETE CRED R Ex 65 KEHRT UG Sage a dab de noe e Ope donde ake Run D cp ene ee e oh sa A 65 Common Command Format ses ee x ROSE EKER ESE SURE 65 SCP Command Format 225 cee 48s eee RE o3 ww OR RA 65 EL 1 ede
65. S REA EERE RO 29 Bridge Winne Diagrams ess Oe eee Ed RR KLE DEER ERS EYES 25 HL Voltmeter DOrnnialS errar 25 Wining a Terminal Module sa p Re d dog de eee ORO AO E Y dikeh 26 Span Gase Worms Diagrams s essu sooo o Re ROO REOR EE RE LE 27 Wining Considerations a 4d do RE dA REY GEES D4 RODE RS 27 19 Bridge Digs 6 3 3 oe be aea k h OS a RA a RR a des 28 12 Bridge Diagrams aiii 29 Full Bridge Dia eri AA AA 30 Connecting Relay Strain Gage Multiplexers to an External Voltmeter 31 Connecting FET Strain Gage Multiplexers to an External Voltmeter 32 HP E1355A 56A 57A 58A Modules User s Manual Contents 1 Chapter 3 Making Strain Gage Measurements o e 33 About Thie Chaplet oc kde aa Se aaa PK UE Re ded 33 Using the Example POE us nu koe Roo ed Dee E YU YS 33 Single Channel 1 4 Bridge Measurements llle 35 Multi Channel 1 4 Bridge Measurements llle 36 Dynamic Strain Measurements ss 2222 be a SRR SOROR RAE RH ERAS 37 Ros tte Measurements uui su ee eR OOS R be RED ER de WR Na 39 Single Channel Bending Full Bridge Measurements 4 40 Relay Strain Gage Measurements with an External Voltmeter 41 FET Strain Gage Measurements with an External Voltmeter 43 Measurements with Downloaded Unstrained References 46 Chapter 4 Understanding the Strain Gage Multiplexers 49 About This Chanter 52s 906 CREE dd AA doe NOR KC ER
66. SCAN SRE STB SPOLL Reading the Operation Status Register after a Scanning Cycle STAT OPER Returns the bit values of the Standard Operation Status Register 256 shows bit 8 is set to 1 0 shows bit 8 is set to 0 read and print the register value Chapter 5 Strain Gage Multiplexer Command Reference 91 SYSTem Subsystem Syntax CDEScription Parameters Comments Example Reading the Description of Multiplexer Card 1 The SYSTem subsystem returns the error numbers and error messages in the error queue of a switchbox and returns the types and descriptions of multiplexers in a switchbox SYSTem CDEScription number CPON number ALL CTYPe number ERRor SYSTem CDEScription number returns the description of a selected multiplexer in a switchbox Parameter Name Parameter Type Range of Values number Numeric 1 to 99 e 8 Channel 1200 Relay Strain Gage Multiplexer Description The SYSTem CDEScription number command returns 8 Channel Relay Strain Gage 120 Ohms e 8 Channel 3500 Relay Strain Gage Multiplexer Description The SYSTem CDEScription number command returns 8 Channel Relay Strain Gage 350 Ohms e 8 Channel 1200 FET Strain Gage Multiplexer Description The SYSTem CDEScription number command returns 8 Channel FET Strain Gage 120 Ohms e 8 Channel 3500 FET Strain Gage Multiplexer Description The SYSTem CDEScription number
67. SUBEND Chapter 3 Making Strain Gage Measurements 41 Comments The strain gage wiring diagram used for this example is on page 28 The diagram showing how the HP 3458A Multimeter is connected to the relay strain gage multiplexer via the mainframe is on page 31 When making strain measurements with an external voltmeter the following voltages are measured in the sequence shown bridge output voltage Vout channels 100 102 unstrained bridge excitation voltage Vs channel 115 unstrained bridge output voltage Vout channels 100 102 strained bridge excitation voltage Vs channel 115 strained These measurements are used to compute Vr which in equation form is defined as Vr z Vout V s strained Vout V s unstrained Vr is then substituted into the equation Table 4 1 for V4 bridge measurements The HP E1300 E1301 mainframe s Event In and Trig Out ports are connected to the voltmeter s VM Compl and Ext Trig ports respectively Thus when a multiplexer channel is closed a channel closed pulse from the mainframe s Trig Out port is applied to the voltmeter s Ext Trig port When the voltmeter measurement is complete the voltmeter complete signal is applied to the Event In port which triggers the multiplexer to close the next channel in the list 42 Making Strain Gage Measurements Chapter 3 FET Strain Gage Measurements with an External Voltmeter This program shows how strain measurements
68. Scription number Returns description of module in a switchbox CPON number ALL Sets specified module to its power on state CTYPe number Returns the module type ERRor Returns error number message in a switchbox to error queue Continued on Next Page Chapter 5 Strain Gage Multiplexer Command Reference 99 TRIGger IMMediate SOURce BUS SOURce DBUS SOURce EXTernal SOURce HOLD SOURce IMMediate Causes a trigger to occur Trigger source is TRG Trigger source is Digital Bus Trigger source is Event In BNC Hold off triggering Continuous internal triggering SOURce Query scan trigger source IEEE 488 2 Common Commands Quick Reference Command Title Description RST Reset Opens all channels and invalidates current channel list for scanning Sets ARM COUN 1 TRIG SOUR IMM and INIT CONT OFF TRG Bus Trigger When scan is enabled and trigger source is TRIG SOUR BUS use the TRG command to trigger the switchbox to advance the scan TST Self Test Power on interrupt returns 110 Incorrect MFR ID or model code returns 103 Test pass returns 0 100 Strain Gage Multiplexer Command Reference Chapter 5 Appendix A HP E1355A E1356A E1357A E1358A Specifications HP E1355A E1356A Relay Strain Gage Multiplexer HP E1357A E1358A FET Strain Gage Multiplexer Maximum Voltage Terminal to Terminal or Terminal to
69. UE CR ORI ci Be OR Sw Hebe ub 87 SENSE uus doses beoe edo Aa RE Peg deed di 88 SER NEO uersu bk gy SARK SEES aa 88 STRGMGEACI N duos ERROR CUR Rx 9 CHER LED EE E RO PRX E S 89 STRAPON IN eso cee eg o oe deeem eoe ak oe qe de Se D n 89 TRAMPOSO be ius be RRO S ACER EC dA REUS RAMA E EO 89 STRAN UNS Trained 2 uu dA NEG xU X X RW X ES Rd EHS 90 SER GWEN S Ted eoo eR eoe hoe pO E eR do 90 SATIS uk Ke d odes o oe 3 9 dd ER GR Ko ab dE ERED Ro EER ERE DES 91 OPERGHIOMENA Be 22444 oe ke RES ODED KA CES ORE REE Se a 91 JOPERSHGDDEVENIZ socias UR 4450064 NO OSS Pe RR 91 STO DM S ark dodo eh ek dodo e dom hee de e died oe aS 92 XODBSSSBHORA 60cs E RGROR OR KERR SEK a SRR RE Bo RRA 92 CPU d sur DiS ae d aro Vor Qo Werbe qe des de RUP d dese rad 93 CTYPE acude d ode pedo ctis deed ire e duco b REOR o og ede deb de dca 93 ERRI 2424x934 50 3579 8 b b SEA ES EES dus SEE d ede d xus 94 TRIG 24 454 ee 45h 24 OH ESS OSS se Ob ewes FRO AUR re 95 DINIMedidiel a Ck hee ho ee SCR EES OSS ESR 95 SOURCE cca etd bd Ode eee BOR EDK ES EE R R HER ERE dep deae oos 95 ODUR xu ake oe CORO RR REE ee Ree A ERE OR RE SRD 97 IEEE 488 2 Common Commands eee eee ees 98 Command Quick Reference ss 64 04 5450464544 454 48 o DES OOH GH 99 HP E1355A 56A 57A 58A Modules User s Manual Contents 3 Appendix A HP E1355A E1356A E1357A E1358A Specifications 101 Relay Lie auae Ree dod ada oo Pod gode be 103 Appendix B Strain Gage Equat
70. UTO and AUTO are third level commands Chapter 5 Strain Gage Multiplexer Command Reference 65 Command Separator A colon always separates one command from the next lower level command as shown below CALibration ZERO AUTO Colons separate the root command from the second level command CALibration ZERO and the second level from the third level ZERO AUTO The parameters of a command are separated from the command by a blank space Abbreviated The command syntax shows most commands as a mixture of upper and Commands lower case letters The upper case letters indicate the abbreviated spelling for the command For shorter program lines send the abbreviated form For better program readability you may send the entire command The instrument will accept either the abbreviated form or the entire command For example if the command syntax shows MEASure then MEAS and MEASURE are both acceptable forms Other forms of MEASure such as MEASU or MEASUR will generate an error You may use upper or lower case letters Therefore MEASURE measure and MeASUFE are all acceptable Command keywords can be entered in their full form as shown above or can be entered in their short form In this manual the entry required in short form commands is always capitalized The short form is generally used for examples in this manual Implied Commands Implied commands are those which appear in square brackets in the command syntax Note t
71. a bridge resistor OUTPUT 70903 MEAS VOLT DC 110 ENTER 70903 V_lower Compute the ratio of the upper bridge leg voltage to the lower bridge leg voltage V_ratio V_upper V_lower PRINT V_upper to V lower ratio V_ratio END A typical output from this program is V upperto V lower ratio 999935 112 Strain Gage Diagnostics Appendix C Shunt Verification The Shunt Verification diagnostic accessed through internal channels 12 and 13 checks the bridge completion circuitry and strain gage arrangement The diagnostic places internal resistors in parallel with an internal bridge arm or strain gage to simulate a known value of tensile or compressive strain This diagnostic can be used on any bridge completion channel A known value of tensile strain is simulated by placing a 158k resistor in parallel with the upper leg 1kQ internal half bridge resistor A known compressive strain is simulated by placing a 59kQ resistor in parallel with the strain gage on the bridge completion channel specified Figure C 4 If the tensile or compressive strain measured is equivalent to the simulated value the bridge completion circuitry is functioning properly and the configuration is set up correctly Rc 59 0K 1 TENSION SHUNT COMPRESSION SHUNT E1355 Figc 4 Figure C 4 Shunt Verification Resistors Appendix C Strain Gage Diagnostics 113 Specification The nominal values of simulated tensile and compressive strain ar
72. a format land turn off the mainframe display Configure the multimeter for V4 bridge strain measurements on channel 0 To achieve 2000 measurements in 1 second specify a fixed lowest range set the aperture time to accept the necessary sample period turn autozero off specify the number of measurements to be taken and specify the source of the sample signal and the sample period OUTPUT 70903 FORM REAL 64 OUTPUT 70903 DISP MON OFF OUTPUT 70903 CONF STR QUAR 100 OUTPUT 70903 VOLT RANG MIN OUTPUT 70903 VOLT APER 100E 6 OUTPUT 70903 CAL ZERO AUTO OFF OUTPUT 70903 SAMP COUN 2000 OUTPUT 70903 SAMP SOUR TIM OUTPUT 70903 SAMP TIM 500E 6 Measure the strain on the specified channel OUTPUT 70903 INIT OUTPUT 70903 FETC Enter and display the readings ENTER Dmm USING X K K Ndig Count 1 VAL Ndig ENTER Dmm Strn_rdgs ENTER Dmm PRINT Strn_rdgs END Chapter 3 Making Strain Gage Measurements 37 Comments e The wiring diagram used for this example is on page 28 Specifying the gage factor as 2 11E 6 returns the strain measurements in microstrain A gage factor must be specified and an unstrained reference must be measured for each channel The REAL 64 format 1s selected because the HP 9000 Series 200 300 computer stores readings in that format REAL 64 data is transferred to the computer in the IEEE 488 2 1987 Definite Length Arbitrary Block format Data in t
73. a trigger occurs during the channel closed pulse the pulse is terminated and the channel is advanced Operates only with downloaded scan list DIR is zero Appendix D Strain Gage Register Based Programming 127 Scan Control Reading the Scan Control Register allows you to check the scan control Register settings base 0616 15 14 13 12 11 10 7 6 5 4 3 2 1 0 Read FF 1 1 1 1 CNT IMM DBS CLR EN EN EN SCN CLR SCN Clear Scan List A one 1 in this bit indicates the scan list is cleared The bit must be set back to zero 0 after it is cleared in order for another scan list to be accepted DBS EN Digital Bus Enable A one 1 indicates the Digital Bus trigger mode is enabled A zero 0 indicates it 1s disabled IMM EN Immediate Enable A one 1 in this bit indicates the immediate trigger mode is set CNTEN Continuous Enable A one 1 in this bit indicates the continuous scanning Scan Channel Delay Register mode is set Reading the Scan Channel Delay Register returns the SETTling TIME delay base 0816 15 14 13 12 11 10 7 6 5 4 3 2 1 0 Read FF 1 1 1 1 D3 D2 D1 DO D3 DO Data bits three to zero The delay is 2 usec and has a range of 0 to 15 as determined by the settings of D3 through DO 128 Strain Gage Register Based Programming Appendix D The WRITE Registers Control Registe
74. ading the ID register 133 register based programming 133 relay strain gage measurements 41 resetting the switchbox 135 rosette measurements 39 single channel 1 4 bridge measurements 35 single channel bending full bridge measurements 40 Programming language example programs 33 register based 119 136 HP E1355A 56A 57A 58A Modules User s Manual Index 143 Q Quarter Bridge bridge completion circuitry 54 leadwire diagnostics 108 measurements 58 multi channel measurements 36 rosette measurements 58 single channel measurements 35 terminals used 25 wiring diagram 25 28 Query analog bus port 86 channel closure 81 error queue 94 gage factor 89 number of scanning cycles 69 poisson ratio 89 scan mode 85 scanning state 76 settling time 87 trig out port state 79 trigger sources 97 unstrained references 90 Quick Reference common commands 100 SCPI commands 99 R RCL 98 READ registers device type register 124 127 FET multiplexers 126 128 ID register 123 126 relay multiplexers 123 124 scan channel delay register 128 scan control register 128 status register 124 127 Reader Comment Sheet 11 Reading device type register 134 ID register example program 133 Register Based Programming 119 136 base address 121 FET multiplexer registers 126 132 FET multiplexer scanning 135 measuring bridge excitation voltage 135 programming examples 133 reading the device type register
75. alidated The scan list however is not affected Trigger Internal A one 1 immediately advances a channel on the scan list a zero 0 is the idle state Bit is automatically set back to zero 0 upon channel advance Appendix D Strain Gage Register Based Programming 129 Scan Control Register The Scan Control Register allows you to clear the scan list set the trigger mode and reset the pointer to the beginning of the scan list base 0616 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined X X X RST ONT IMM DBS CLR PTR EN EN EN SCN CLR SCN DBS EN IMM EN CNT EN RST PTR Scan Channel Delay Register Clear Scan List A one 1 in this bit clears the scan list The bit must be set back to zero 0 in order for another scan list to be accepted Digital Bus Enable A one 1 enables the Digital Bus trigger mode A zero 0 disables it Immediate Enable A one 1 in this bit sets trigger to immediate which means that as soon as the first channel is closed by the TRG INT the entire scan list is run without any further triggering Channel advance speed is determined by the delay time specified Extremely limited applications Continuous Enable A one 1 in this bit enables the card to continually cycle through the scan list When this bit is enabled the last channel in a scan list resets the pointer back to the beginning of the
76. alues of the Operation Status Register This subsystem enables a bit to be set to 1 in the Status Register after a bit is set to 1 in the Operation Status Register STATUS OPERation ENABIe number EVENt STATus OPERation ENABle number enables the Operation Status Register to set a bit in the Status Register For multiplexer modules when bit 8 in the Operation Status Register is set to 1 bit 7 in the Status Register is set to 1 Parameter Name Parameter Type Range of Values number Numeric 1 to 32768 Setting Bit 7 of the Status Register STATus OPERation ENABle 256 allows bit 7 of the Status Register to be set to 1 after bit 8 of the Operation Status Register is set to 1 e Related Commands ROUTe SCAN SRE STB SPOLL Enabling the Status Register Bit 7 STAT OPER ENAB 256 Enables bit 7 of the Status Register to be set STATus OPERation EVENt returns the bit value of the Operation Status Register only bit 8 is used by the multiplexer modules Setting Bit 8 of the Operation Status Register Bit 8 Scan Complete is set to 1 after a scanning cycle completes Bit 8 returns to O after sending the STATus OPERation EVENt command Returned Data after sending the STATus OPERation EVENt Command The command returns 256 if bit 8 of the Operation Status Register is set to 1 The command returns 0 if bit 8 of the Operation Status Register is set to 0 e Related Commands ROUTe
77. amples are found in Chapter 3 The diagnostics are covered in Appendix C Note The electrical characteristics and strain measurement circuitry used by the strain gage multiplexers are covered in Chapter 4 Using the Multiplexers in a VXlbus System This section prepares the strain gage multiplexers for use in a VXIbus system Identifying the The card ID jumpers and card ID switch Figure 1 1 indicates which Terminal Module terminal assembly is used Since the HP E1345 66201 and HP E1351 66201 assemblies are used with a variety of terminal modules the ID jumpers or ID switch may need to be changed To reduce setup time and avoid configuration errors check the jumper or switch setting to make sure they match the terminal module used Relay Multiplexers When the relay strain gage multiplexers are shipped from the factory the card ID jumpers are set according to the terminal module E1355A E1356A shipped with them Figure 1 1 The system is able to identify the multiplexer with or without the terminal module attached Note If the jumper setting does not match the terminal module attached the system will identify the card based on the jumper setting 14 Getting Started with the Strain Gage Multiplexers Chapter 1 FET Multiplexers When the FET strain gage multiplexers are shipped from the factory the card ID switches are set to the OPEN 0 position Figure 1 1 The terminal module is identified when the module is plugged onto the
78. ands The following table lists the IEEE 488 2 Common Commands that the 8 Channel Relay and FET Strain Gage Multiplexer Modules accept For more information on Common Commands refer to the HP 75000 Series B Mainframe User s Manual HP Model Number E1300 E1301 or the ANSI IEEE Standard 488 2 1987 Command Title Description IDN Identification Returns identification string of the switchbox RST Reset Opens all channels and invalidates current channel list for scanning Sets ARM COUN 1 TRIG SOUR IMM and INIT CONT OFF TST Self Test Power on interrupt returns 110 Incorrect MFR ID or model code returns 103 Test pass returns 0 OPC Operation Complete See note below OPC Operation Complete Query See note below WAI Wait to Complete See note below CLS Clear status Clears all status registers see STATus OPERation EVENIt ESE Event status enable See note below ESE Event status enable query See note below ESR Event status register query See note below SRE Service request enable Enables status register bits see Chapter 4 for operation SRE Service request enable query See note below STB Read status byte query See note below TRG Trigger Triggers the switchbox to advance the scan when scan is enabled and trigger source is TRIGger SOURce BUS HOLD RCL Recall instrument state See note below SAV Store instrument state See no
79. ard Series 300 computer Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Measure the unstrained reference voltage on the bridge output channel used OUTPUT 70903 CAL STR 100 Measure the simulated tension strain on the bridge output channel OUTPUT 70903 MEAS STR QTEN 100 ENTER 70903 Tension Measure the simulated compressive strain on the bridge output channel OUTPUT 70903 MEAS STR QCOM 100 ENTER 70903 Compress Display the tension and compression shunt in microstrain PRINT Tension shunt Tension 1 E 6 PRINT PRINT Compression shunt Compress 1 E 6 END A typical output from this program is HP E1356A used Tension shunt 3170 007 Compression shunt 2967 231 Appendix C Strain Gage Diagnostics 115 Guard Voltage The Guard Voltage diagnostic accessed through internal channel 14 measures the guard voltage This measurement verifies that the guard on the relay strain gage multiplexers is driven to the necessary potential by the Wagner Ground The proper potential minimizes leakage currents caused by low gage isolation resistance Figure C 5 shows how the guard is driven to a known voltage and where that voltage is measured WAGNER m gt GROUND Ch14 511 M LIE 1200 vs 2 10005 OR 550 1 TO SPECIMEN Via ACCESSORY GUARD E1355 Figc 5 TERMINAL Figure C 5 Driving the Card Specification The guard voltage shoul
80. asurements only TRIGger SOURce IMM trigger signal is always true Measurement is taken when multimeter goes to trigger state TRIGger COUNt 1 number of triggers issued or number of scans through channel list before multimeter returns to idle state TRIGger DELay AUTO delays are 0 seconds for DC voltage and resistance 0 5 seconds for AC voltage SAMPle COUNt 1 number of measurements taken when trigger is received SAMPle SOURce IMM period between measurements or the period between FET multiplexer scans Subsystem Syntax Refer to Chapter 5 in the HP E1326B E1411B Multimeter User s Manual for more information on the CONFigure subsystem CONFigure STRain lt strain_function gt channel list Chapter 5 Strain Gage Multiplexer Command Reference 71 STRain CONFigure STRain strain function channel list configures the multimeter for strain measurements using the specified bridge arrangement on the specified channel Parameters Parameter Name Parameter Type Range of Values strain function Discrete QUARter HBENding HPOisson FBENding FPOisson FBPoisson QTENsion QCOMpression UNSTrained channel_list Numeric 00 07 Comments e The strain measurements specified by the strain_function parameter are QUARter V4 bridge measurements HBENding Bending Y bridge measurements HPOisson Poisson Y bridge measurements FBENding Bending Full bridge measure
81. can mode The command returns NONE VOLT or RES if the scan mode is in the NONE VOLT or RES mode respectively Query Scan Mode Since this example selects the VOLT mode the query command returns VOLT SCAN MODE VOLT Selects the voltage scanning mode SCAN MODE Query the scanning mode Chapter 5 Strain Gage Multiplexer Command Reference 85 SCAN PORT ROUTe SCAN PORT port enables or disables the tree isolation switches FET multiplexers or the AT BT and AT2 tree switches relay multiplexers SCAN PORT ABUS closes the appropriate tree switches for the analog bus connections The ROUTe SCAN PORT NONE command disables the tree switches and leaves them open Parameters Parameter Name Parameter Type Range of Values port Discrete ABUS NONE Comments e Order of Command Execution The ROUTe SCAN PORT command must be executed before the ROUTe SCAN channel list and ROUTe CLOSe channel list commands e RST Condition ROUTe SCAN PORT NONE Example Selecting the ABUS Port TRIG SOUR EXT Selects external trigger source SCAN MODE VOLT Selects the voltage scanning mode SCAN PORT ABUS Selects the ABUS port SCAN 100 107 Sets channel list INIT Starts scanning cycle SCAN PORT ROUTe SCAN PORT returns the current state of the analog bus port The command returns NONE if the analog bus connection control relays are disabled or ABUS if the control relays are enabled Example Que
82. channels use OPEN Gccnn ccnn a group of sequential channels use OPEN cenn ccnn ccnn cenn orany combination Opening order for multiple channels with a single command is not guaranteed Opening the AT BT AT2 and RT Tree Switches relay multiplexers Use channel numbers 90 91 92 and 93 to open the AT BT AT2 and RT tree switches respectively e Related Commands ROUTe CLOSe ROUTe OPEN e RST Condition All multiplexer channels are open Example Opening Multiplexer Channels This example opens channel 0 of switchbox multiplexer card number 1 OPEN 100 100 opens channel 0 of multiplexer 7 OPEN ROUTe OPEN channel list returns the current state of the channel s queried The channel list is in the form ccnn The command returns 1 if the channel is open or returns 0 if the channel is closed Comments e Query is Software Readback The ROUTe JOPEN command returns the current software state of the channel specified It does not account for relay hardware failures Example Query Multiplexer Channel Open State OPEN 100 100 opens channel 0 of multiplexer 1 OPEN 100 Query channel 0 82 Strain Gage Multiplexer Command Reference Chapter 5 SCAN ROUTe SCAN channel list defines the switchbox channels to be scanned The channel list is in the form ccnn ccnn ccnn ccnn ccnn or cenn ccnn ccnn ccnn where cc card number 00 99 and nn channel number 00 15 in
83. chbox CALL Swbx_rst END Subroutine which resets the switchbox by writing a 1 and a 0 to Control Register bit 0 SUB Swbx rst COM Base addr OUTPUT 70900 DIAG POKE Base_addr 4 16 1 OUTPUT 70900 DIAG POKE Base_addr 4 16 0 SUBEND This program closes internal channel 15 and tree switch 90 in order to measure the bridge excitation voltage for a relay multiplexer switchbox Convert the switchbox base address to decimal and store the value in a variable COM Base addr Base addr DVAL 1FDCO00 16 Call the subroutine which measures the bridge excitation voltage CALL Ex_volt END Subroutine which closes internal channel 15 in the Channel Register and tree relay 90 in the Tree Switch Register in order to access and measure the bridge excitation voltage SUB Ex_volt COM Base addr OUTPUT 70900 DIAG POKE Base_addr 8 16 H8000 OUTPUT 70900 DIAG POKE Base_addr 6 16 H1 SUBEND This program makes 1 4 bridge strain measurements on three FET multiplexer channels using an external HP 3458A multimeter The program clears the FET multiplexer s Scan Control Register downloads the scan list sets the settling time and then starts the scan The multimeter is connected to the multiplexer as indicated in Figure 2 8 Dimension computer variables to store the bridge output and bridge excitation voltages DIM Vout unstr 1 3 Vout str 1 3 Vr 1 3 Epsilon 1 3 Appendix D Strain Gage Register Based Progra
84. cludes internal diagnostic channels Parameters Parameter Name Parameter Type Range of Values channel list Numeric cc00 cc15 Comments Channel List relay and FET multiplexers Valid scanning lists asingle channel use ccnn for multiple channels use ccnn ccnn sequential channels use ccnn ccnn a group of sequential channels use ccnn ccnn ccnn ccnn orany combination Defining the Channel List When executing ROUTe SCAN the channel list is checked for valid card and channel numbers An error is generated for an invalid channel list Downloading a FET Multiplexer Scanning List When TRIG SOUR DBUS or TRIG SOUR IMM is set the channel list for the SCAN command is automatically downloaded into RAM on the FET multiplexer The channels are advanced via the digital bus and no direct intervention by the mainframe CPU is required If the switchbox instrument contains FET and relay multiplexers the scan list is not downloaded but is still scanned Scanning Operation With a valid channel list INITiate IMMediate starts the scanning cycle and closes the first channel in the channel list Successive triggers from the source specified by TRIGger SOURce advances the scan through the channel list Stopping Scan See the ABORt command Closing the AT BT and AT2 Tree Switches relay multiplexers See the ROUTe SCAN PORT ABUS command Related Commands TRlIGger TRIGger SOURce
85. command DBUS Discrete Digital Bus EXTernal Discrete Event In BNC port HOLD Discrete Hold triggering IMMediate Discrete Continuous triggering Chapter 5 Strain Gage Multiplexer Command Reference 95 Comments Enabling the Trigger Source The TRIGger SOURce command only selects the trigger source The INITiate IMMediate command enables the trigger source e Using the TRIG command You can use TRIGger IMMediate to advance the scan when TRIGger SOURce BUS or TRIGger SOURce HOLD is selected Using Digital Bus Triggering TRIGger SOURce DBUS selects the digital bus on the FET multiplexer as the trigger source Any open collector TTL trigger source can be wired to the Channel Advance left most lead A negative going pulse triggers the multiplexer and advances it to the next channel on the scanning list After the SETTling TIME delay the multiplexer asserts channel closed right most lead on the digital bus Digital bus triggering is available with the FET multiplexers only Using External Trigger Inputs Only one switchbox at a time can use the TRIGger SOURce EXTernal trigger input on the HP E1300 E1301 Mainframe Event In BNC port The trigger input is assigned to the first switchbox requesting the external trigger source Assigning External Trigger A switchbox assigned with TRIGger SOURce EXTernal remains assigned to that source until it receives a command to change the source When the
86. d Close the multiplexer tree relays necessary to make DC voltage measurements Connect the analog bus which carries the bridge output and excitation voltages to the HI LO and Guard terminals on the multiplexer terminal module OUTPUT 70914 RST OUTPUT 70914 OUTP ON OUTPUT 70914 TRIG SOUR BUS OUTPUT 70914 SCAN MODE VOLT OUTPUT 70914 SCAN PORT ABUS Measure Vout and Vs unstrained INIT closes the first channel in the list TRG is used to advance and complete the scan The WAIT statements allow the voltmeter measurement to complete before the next channel is closed OUTPUT 70914 SCAN 100 102 115 OUTPUT 70914 INIT WAIT 1 FOR l 1 TO 4 OUTPUT 70914 TRG WAIT 1 NEXT DISP Add tension to the specimen then press Continue PAUSE DISP n Measure Vout and Vs strained Again INIT closes the first channel in the list Backplane triggers TRG are issued to advance and complete the scan The WAIT statements allow the voltmeter measurement to complete before the next channel is closed OUTPUT 70914 SCAN 100 102 115 OUTPUT 70914 INIT WAIT 1 FOR l 1 TO 4 OUTPUT 70914 TRG WAIT 1 NEXT This modification allows the multimeter to be triggered when a multiplexer channel is closed However the multiplexer is triggered by the user TRG which advances the scan Chapter 3 Making Strain Gage Measurements 45 Measurements with Downloaded Unstrained References In certain app
87. d SH e ed 124 The WRITE REESE A boolean c OR HP wd 125 Lon r 1 a paw ek Sd EUR e d TOUR Oe PARDEE REED 125 Tee Switch REECE 4 ae OER Se eu d ded EGRE KEW qd Rx 44 125 Channel IRE occorre dodo bobo dos Sek wee ded dio do Poo Fee eds 125 FET Multiplexer Rege 22 oos Rok OE SURE MOEA SERRE REREAD 126 The READERS 22 bu ae eRe OOK AAA ERS Euh Yos 126 ID RUNE 2k cao d eg ed d d Ee boe ae gl ie od tio 126 Device Type Register oo o eRe eg dex ox 9 OO o EERE DES 127 Dias T 6 mL TIT 127 acan Conto Berisso e OR RO eR De Re 128 Scan Channel Delay Register o o K K un cn RR ORO EEE E K 128 The WRITE RAgINISE aono OCURRE RRA Cone REOR be 129 CONG OCI CT Pc Ok Soh eR Ae E 129 Scan Control RES soa ko dee HRS REE diede de XR OED DE OO 130 Scan Channel Delay Register lt 2 dopo ae KR A EE 130 Scan Channel Configuration Register 2 444466 4 620 ee RR Rx 131 Direct Channel Configuration Register 22s 152 Direct Control L gn cd kee eR EEK SEDER RORCRORGR E S EDGE A 132 4 HP E1355A 56A 57A 58A Modules User s Manual Contents Programming Examples a uu uoo A EROR GER OR UR On Rope Ke pe o eod 133 Reading the ID Begislef 22e suo RES Ed dX 4 9 3 Oe RE ROR ENE A 133 Reading the Device Type Register ia xR R oko Xx REOR 134 Resting tho SWING uu acc SEE Se A E de AUR dO Kee 135 Measuring the Bridge Excitation Voltage o o o 135 BET Wultiplexer Scanning 442 54 RR Rho a ER RS SRA EE Re 135 Appendix E Strain Gage Multiplexer Error
88. d as the instrument identifier The instrument identifier is the module with a logical address that is a multiple of 8 8 16 24 The multiplexers in the switchbox instrument must have successive logical addresses beginning with the logical address of the instrument identifier For example the multiplexers in a switchbox might have logical addresses of 112 113 114 and so on All strain gage multiplexers have a factory set logical address of 112 The logical address is changed using the logical address switches shown in Figure 1 5 Note Detailed information on creating virtual instruments in a V XIbus system can be found in the HP 75000 Series B Installation and Getting Started Guide or in the HP E1406A Command Module User s Manual The Logical Address is determined 1648 24 by the sum of the switches in the closed 1 position 128 FX N Oo OM c N 1 fel fo fo FP fo o o o ed led ed fo 9 led log jogo A 5682 1 8 Switch address set to 24
89. d be 4 the bridge excitation voltage 2 Set Up To perform the guard voltage diagnostic your system should be configured as follows 1 If the bridge excitation voltage is externally supplied connect the supply to the terminal module as shown in Figure C 1 Set the voltage to 5 0V 2 If desired connect the bridge arrangement to the bridge completion channels Strain gages do not have to be connected for this diagnostic CAUTION Use care when externally supplying the bridge excitation voltage Voltages greater than 5 4V may damage the bridge completion resistors 116 Strain Gage Diagnostics Appendix C Procedure Measure the guard voltage on internal channel 14 MEASure VOLT DC 114 The following example measures the guard voltage The program assumes the strain gage multiplexer is used with the HP E1326B E1411B multimeter as part of a scanning multimeter instrument The computer syntax used is HP BASIC running on a Hewlett Packard Series 300 computer Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Measure the guard voltage on internal channel 14 OUTPUT 70903 MEAS VOLT DC 114 ENTER 70903 G_volt Print the guard voltage PRINT Guard voltage G_volt END A typical output from this program is Guard voltage 2 5233 Appendix C Strain Gage Diagnostics 117 Bridge Excitation Voltage The Bridge Excitation Voltage diagnostic accessed through internal channel 15 measures the
90. e COM Base addr Base addr DVAL 1FDCO0 16 Call the subroutine which reads the ID Register CALL Peek id END Subroutine to read the ID Register SUB Peek id COM Base addr OUTPUT 70900 DIAG PEEK Base_addr 0 16 ENTER 70900 Register Hex IVAL Register 16 PRINT Hex SUBEND This program returns FFFF Appendix D Strain Gage Register Based Programming 133 Reading the Device The Device Type Register contains the model code of the device The Ty pe Regi ster model codes for the strain gage multiplexers are FF04 HP E1355A FF06 HP E1356A FF14 HP E1357A FF16 HP E1358A Convert the switchbox base address to decimal and store the value in a variable COM Base addr Base addr DVAL 1FDCO00 16 Call the subroutine which reads the Device Type Register CALL Peek dt END Subroutine to read the Device Type Register SUB Peek dt COM Base addr OUTPUT 70900 DIAG PEEK Base_addr 2 16 ENTER 70900 Register Hex IVAL Register 16 PRINT Hex SUBEND A typical return is FFO6 HP E1356A 134 Strain Gage Register Based Programming Appendix D Resetting the Switchbox Measuring the Bridge Excitation Voltage FET Multiplexer Scanning This program resets the switchbox relay or FET by writing to bit 0 of the Control Register Convert the switchbox base address to decimal and store the value in a variable COM Base addr Base addr DVAL 1FDCO0 16 Call the subroutine which resets the swit
91. e discarded Example Reading the Error Queue SYST ERR Query the error queue 94 Strain Gage Multiplexer Command Reference Chapter 5 TRIGger Subsystem Syntax IMMediate Comments Example SOURce Parameters The TRIGger subsystem commands control the triggering operations of the multiplexer switchbox TRIGger IMMediate SOURce source SOURce TRIGger IMMediate executes a trigger when the defined trigger source is TRIGger SOURce HOLD or TRIGger SOURce BUS Note that TRIGger IMMediate is NOT the same as TRIGger SOURce IMMediate e Executing the TRIGger IMMediate Command A channel list must be defined with ROUTe SCAN lt channel_list gt and an INITiate IMMediate command must be executed before TRIGger IMMediate can trigger the switchbox HOLD or BUS Source Remains If selected the TRIGger SOURce HOLD or TRIGger SOURce BUS commands remain in effect after triggering the switchbox with the TRIGger IMMediate command e Related Commands INITiate ROUTe SCAN Advancing Scan using the TRIGger Command TRIG SOUR HOLD Sets trigger source to hold SCAN 100 107 Sets channel list INIT Starts scanning cycle loop statement Start count loop TRIG Advances scan to next channel increment loop Increment count loop TRIGger SOURce source specifies the trigger source to advance the channel list during scanning Parameter Name Parameter Type Range of Values BUS Discrete TRG
92. e 2 1B indicate the connections between the strain gage bridge arrangement and the channel terminals The six points on the diagrams E El E2 H L and G correspond to the six wiring terminals on each bridge completion channel These points also correspond to the points shown on the Wheatstone Bridge on page 54 The terminals used by the bridge configurations are e Vibrdge E E1 H G e 1 bridge E E2 H G e full bridge E E2 H L G An example of how the diagram relates to gage wiring is shown for the 1 4 bridge arrangement in Figure 2 2 H L G IS IS SAMPLE E 9H O 1 E1 al O S a a L R e c SHIELD 1 4 Bridge e lol lO FE E1 E2 Figure 2 2 1 4 Bridge Arrangement Wiring Diagram E1355 F 2 2 H L G Voltmeter The common high H low L and guard G terminals are the same point Terminals electrically as the H L and G terminals of the bridge completion channels These common terminals allow for strain measurements using an external voltmeter see Measurements Using an External Voltmeter on page 63 Chapter 2 Connecting Strain Gages to the Multiplexers 25 Wiring a Terminal Module Remove Clear Cover 2 Unscrew And Remove Strain Relief Repeat At This Slot
93. e given in Table C 2 Note that lead resistance between the strain gage and the bridge completion circuitry will affect the readings associated with the compression diagnostic for all bridge arrangements and the tension diagnostic for full bridge arrangements Table C 2 Simulated Tension and Compression Strain Values Channel Diagnostic Compression Nominal Nominal HP E1355A 3170 1026 HP E1356A 3170 2967 NOTES 1 Forfull bridge arrangements only add 12 5ue for each ohm of lead resistance For lead resistances 1 ohm multiply the resistance by 12 5 to determine the amount of correction 2 Eor all arrangements subtract 16 7ue for each ohm of lead resistance For lead resistances 1 ohm multiply the resistance by 16 7 to determine the amount of correction 3 All values are in pe To increase measurement accuracy leadwire corrections are included in the table under Notes to compensate for leadwire resistances Refer to the Leadwire Resistance diagnostic to determine the leadwire resistance of your bridge arrangement Determining the leadwire resistance is not a prerequisite for this diagnostic Set Up To perform the shunt verification diagnostic your system should be configured as follows 1 Connect the bridge excitation voltage to the terminal module as shown in Figure C 1 Set the voltage to 5 0V 2 Connect the bridge arrangement s V4 V5 or full to undergo the
94. e instrument is covered in the HP E1326B E1411B Multimeter User s Manual Appendix D Strain Gage Register Based Programming 119 Register Addressing Register addresses for register based devices are located in the upper 2596 of VXIbus A16 address space Every VXIbus device up to 256 is allocated a 64 byte block of addresses The HP E1355A and E1356A Relay Strain Gage Multiplexers with five registers use five of the 64 addresses allocated The HP E1357A and E1358A FET Strain Gage Multiplexers with eight registers use eight of the 64 addresses allocated Figure D 1 shows the register address location within A16 Figure D 2 shows the location of A16 address space in the HP E1405 E1406 Command Module and HP E1300 E1301 Mainframe As an example both figures show the register map for the HP E1351A E1353A FET Multiplexers This map is also the same for the HP E1357A E1358A FET Strain Gage Multiplexers FFFF 16 FFFF 16 ee 16 BIT WORDS C00016 REGISTER 29 ADDRESS Z SEE SPACE SC 16 N e e A16 e e ADDRESS e e SPACE OE 16 Direct Control Register UC 16 Direct Channel Configuration Register 200016 OA16 Scan Channel Configuration Register N 0816 Scan Channel Delay Register 49 152 0616 Scan Control Register N 0416 Status Control Register 0216 Device Type Register 0016 Manufacturer ID Register HP E1351A E1353A 000016 Register Map Base Addr
95. easurements allow you to compute the value of Vr which in equation form is defined as Vr z Vout V s strained Vout V s unstrained Vr is then substituted into the appropriate equation Table 4 1 on page 52 based on the bridge arrangement used Examples of strain measurements using the relay and FET multiplexers and an external voltmeter are contained in Chapter 3 Chapter 4 Understanding the Strain Gage Multiplexers 63 Voltage and Resistance Measurements The strain gage multiplexers can be used for DC voltage and 2 wire ohms measurements When making these measurements on the bridge completion channels the channel s bridge selection jumper must be set to the FULL position DC voltages and resistances are connected to the HI LO and G guard terminals of the bridge completion channels If you are using an HP E1326B E1411B Multimeter the guard lead must be connected Note Two wire resistance measurements with an HP E1357A or E1358A FET Strain Gage Multiplexer will be in error by hundreds of ohms This is due to the on resistance of the FET which is in series with resistance being measured Refer to the HP E1326B E1411B Multimeter User s Manual for information on DC voltage and resistance measurements 64 Understanding the Strain Gage Multiplexers Chapter 4 Chapter 5 Strain Gage Multiplexer Command Reference About This Chapter Command Types Common Command Format SCPI Command Format Thi
96. ed reference for each channel OUTPUT 70903 CAL STR 100 102 DISP Add tension to the specimen then press Continue PAUSE DISP Measure the strain on the specified channels Enter and display the readings OUTPUT 70903 MEAS STR QUAR 100 102 ENTER 70903 Strn_rdgs PRINT Strn rdgs END Comments The wiring diagram used for this example is on page 28 e Specifying the gage factor as 2 11E 6 returns the strain measurements in microstrain A gage factor must be specified and an unstrained reference must be measured for each channel 36 Making Strain Gage Measurements Chapter 3 Dynamic Strain Measurements This program makes 2 000 V4 bridge strain measurements over a period of one second The measurements are made on channel 0 of multiplexer card number 1 Dimension computer variables to store the data header and readings Assign lan input output path between the multimeter and computer This is a path for data in the REAL 64 format Clear the path and reset the multimeter DIM Ndig 1 Count 9 Strn rdgs 1 2000 ASSIGN Dmm TO 70903 FORMAT OFF CLEAR Dmm OUTPUT 70903 RST Specify the gage factor for the channel measured OUTPUT 70903 STR GFAC 2 11E 6 100 Measure the channel s unstrained reference OUTPUT 70903 CAL STR 100 DISP Add tension to the specimen then press Continue PAUSE DISP nn To increase throughput speed specify the multimeter s REAL 64 dat
97. ent circuitry associated with 1 4 l and full bridge measurements The sections of this chapter are e Making Strain Measurements 004 Page 49 e Strain Gage Multiplexer Block Diagrams Page 52 Understanding the Strain Gage Measurement bini LET Page 53 e Understanding the Bridge Configurations Page 58 e Measurements Using an External Voltmeter Page 63 e Voltage and Resistance Measurements Page 64 Making Strain Measurements This section explains the procedure used to make strain measurements Also covered are the equations in the instrument firmware which calculate the measured strain Strain The procedure for making strain measurements with the HP E1355A Measurement E1358A Strain Gage Multiplexers and HP E1326B E1411B Multimeter is Procedure 1 Specify the Gage Factor and for Poisson configurations the Poisson Ratio STRain GFACtor gage_factor channel_list STRain POlSson poisson_ratio channel_list One gage_factor and poisson_ratio Poisson configurations must be specified for each channel 2 Measure the unstrained reference voltage CALibration STRain channel_list One unstrained reference voltage measurement must be made on each channel Note that this command leaves the HP E1326B E1411B Multimeter configured for an unstrained reference voltage measurement The multimeter must be reconfigured to make the strain measurement Step
98. er Module Model Number The SYSTem CTYPe number command returns HEWLETT PACKARD E1358A 0 A 03 00 Note The 0 after the module number is the serial number of the module always 0 A 03 00 is an example of the module revision code number Example Reading the Model Number of Multiplexer Card 1 SYST CTYP 1 Determine the model number Chapter 5 Strain Gage Multiplexer Command Reference 93 ERROr system ERRor returns the error numbers and corresponding error messages in the error queue of a switchbox See Appendix E for a listing of switchbox error numbers and messages Comments Error Numbers Messages in the Error Queue Each error generated by a switchbox stores an error number and corresponding error message in the error queue Each error message can be up to 255 characters long Clearing the Error Queue An error number message is removed from the queue each time the SYSTem ERRor command is sent The errors are cleared first in first out When the queue is empty each following SYSTem ERRor command returns 0 No error To clear all error numbers messages in the queue execute the CLS command e Maximum Error Numbers Messages in the Error Queue The queue holds a maximum of 30 error numbers messages for each switchbox If the queue overflows the last error number message in the queue is replaced by 350 Too may errors The least recent error numbers messages remain in the queue and the most recent ar
99. es at right angles on the specimen Mounting the gages in this manner is known as a Poisson arrangement and is represented in Figure 4 11 With a Poisson arrangement the sensitivity is not as great as with the bending 1 2 bridge however it is approximately 25 greater than a V4 bridge arrangement Again since the gages are adjacent legs of the Wheatstone Bridge circuit complete temperature compensation is achieved Figure 4 11 Strain Gages in Poisson Arrangement Dummy Gage Tn a dummy gage configuration one of the strain gages in the Y bridge arrangement is mounted to an unstrained portion of the specimen Figure 4 12 This gage arrangement provides complete temperature compensation however measurement sensitivity is not increased since a 1 4 bridge measurement is made with the one active gage UNSTRAINED dummy GAGE R1 Rg R2 Rdummy E1355 FIG4 12 Figure 4 12 Dummy Gage Arrangement 60 Understanding the Strain Gage Multiplexers Chapter 4 Full Bridge In a full bridge arrangement strain gages are used in all four legs of the Measurements Wheatstone Bridge circuit Figure 4 13 The full bridge arrangement has the highest sensitivity and accuracy of any bridge arrangement and it provides complete temperature compensation for temperature induced apparent strain The full bridge strain measurements available based on gage positioning are described in the following sections
100. escribes the strain gage measurement circuits used by each strain gage multiplexer These circuits include e Wheatstone Bridge e Chevron Bridge e Wagner Ground Chapter 4 Understanding the Strain Gage Multiplexers 53 The Wheatstone The Wheatstone Bridge Circuit shown in Figure 4 2 is the fundamental Bridge strain measuring circuit phe Tice G GUARD CONNECTED TO TEST SAMPLE Figure 4 2 The Wheatstone Bridge When a strain gage is wired to a bridge completion channel it completes the Wheatstone Bridge circuit as indicated in Figure 4 3 This circuit represents a V4 bridge arrangement where only one arm contains an active element strain gage The other arms are fixed value resistors as shown or they may represent unstrained gages Figure 4 3 Bridge Completion Circuitry 1 4 Bridge In a bridge arrangement the 120Q or 350Q bridge completion resistor is replaced by a strain gage when the gages are connected to the terminals as indicated in Figure 4 4 54 Understanding the Strain Gage Multiplexers Chapter 4 Figure 4 4 Bridge Completion Circuitry 1 2 Bridge For a full bridge arrangement strain gages comprise all four arms of the Wheatstone Bridge Figure 4 5 Note the position of the bridge selection jumper required to configure the channel for full bridge measurements GAGE WIRING TERMINATIONS GND CHASSIS ON CARD EXCITATION VOLTAG
101. ess 00016 Logical Address 64 16 or 49 152 Logical Address 64 10 Register Address Base address Register Offset Figure D 1 Multiplexer Registers within A16 Address 120 Strain Gage Register Based Programming Appendix D FFFFFF 16 E0000016 20000016 IF000016 00000016 The Base Address A16 Address Space Outside the Command Module or Mainframe E1301 E1406 ADDRESS MAP A24 ADDRESS SPACE Register J Offset 16 BIT WORDS 20000016 7 SE 16 5C16 IFCOOO Le 20000016 e e A16 N o o ADDRESS N REGISTER SPACE ADDRESS OE 16 Direct Control Register N SPACE UC 15 Direct Channel Configuration Register OA16 Scan Channel Configuration Register 0816 Scan Channel Delay Register IF000016 IFCOO016 0616 Scan Control Register 2 080 768 N 0416 Status Control Register 0216 Device Type Register Base Address IFCOOO 6 Logical Address 64 16 0015 Manufacturer ID Register or HP E1351A E1353A 2 080 768 Logical Address 64 4o Register Map Register Address Base address Register Offset Figure D 2 Mainframe Command Module A16 Address Space When you are reading or writing to a multiplexer register a hexadecimal or decimal register address is specified This address consists of a base address plus a register offset The base address used in register based programming depends on whether
102. gage factor for each channel measured OUTPUT 70903 STR GFAC 2 075E 6 100 102 GFAC 2 11E 6 101 Measure the unstrained reference for each channel OUTPUT 70903 CAL STR 100 102 DISP Add tension to the specimen then press Continue PAUSE DISP Measure the strain on the specified channels Enter and display the readings OUTPUT 70903 MEAS STR QUAR 100 102 ENTER 70903 Strn_rdgs E1 Strn_rdgs 1 E2 Strn_rdgs 2 E3 Strn_rdgs 3 Epsilon 5 E1 E3 E1 E3 2 2 E2 E1 E3 2 5 Sigma 10 4 2 E1 E3 1 32 1 1 32 E1 E3 2 2 E2 E1 E3 2 5 Theta 5 ATN 2 E2 E1 E3 E1 E3 PRINT Epsilon PRINT Sigma PRINT Theta END Comments The wiring diagram used for this example is on page 28 A gage factor must be specified and an unstrained reference must be measured for each channel e A rosette measurement is a series of three 1 4 bridge measurements channels 100 102 Each measurement is substituted into the applicable equation The rosette equations used in this program are listed in Appendix B For this program a poisson ratio V of 0 32 and modulus of elasticity E of 10 4 are assumed Chapter 3 Making Strain Gage Measurements 39 Single Channel Bending Full Bridge Measurements This program makes a bending full bridge strain measurement on channel 7 of multiplexer card number 1 Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Specify the gage
103. gether with the HP E1326B E1411B Multimeter provide static and dynamic strain measurement capabilities for an HP Series B or Series C VXIbus system Physical The HP E1355A and E1356A are B size 8 channel 120Q and 350Q Description RELAY Strain Gage Multiplexers respectively The HP E1355A and E1356A terminal modules use the HP E1345 66201 component assembly The relay multiplexers use a single B size or C size mainframe slot The HP E1357A and E1358A are B Size 8 channel 120Q and 350Q FET Strain Gage Multiplexers respectively The E1357A and E1358A terminal modules use the HP E1351 66201 component assembly The FET multiplexers also use a single B size or C size mainframe slot Functional The measurement capabilities of the relay and FET strain gage multiplexers Description include the following e Y Bridge Measurements 8 Channels Rosettes e 1 Bridge Measurements 8 Channels Bending Y Bridge Poisson Y Bridge Chapter 1 Getting Started with the Strain Gage Multiplexers 13 e Full Bridge Measurements 8 Channels Bending Full Bridge Bending Poisson Full Bridge Poisson Full Bridge e Guarded DCV Voltage and 2 wire Resistance Measurements 8 Channels Allowed with strain measurements on adjacent channels e Diagnostics Leadwire Resistance channels 0 and 1 Internal Half Bridge Voltage Shunt Verification E1355A and E1356A only Guard Voltage Bridge Excitation Voltage Strain measurement ex
104. gister base 0216 e Status Register base 0416 e Scan Control Register base 0616 e Scan Channel Delay Register base 0816 The FET multiplexer s ID Register indicates the classification addressing mode and manufacturer of the device base 0016 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Read Device Class Address Manufacturer ID Mode Device Class Device Classification Bits 15 and 14 classify a device as one of the following 0 0 memory device O 1 extended device 1 0 message based device 1 1 register based device The HP E1357A E1358A FET Strain Gage Multiplexers are register based devices Address Space Addressing Mode Bits 13 and 12 indicate the addressing mode used by the device A16 A24 address mode A16 A32 address mode RESERVED A16 address mode k O GO The HP E1357A E1358A FET Strain Gage Multiplexers use the A16 address mode 126 Strain Gage Register Based Programming Appendix D Manufacturer Identification Device Type Register Manufacturer ID Bits 11 through 0 identify the manufacturer of the device Hewlett Packard s ID number is 4095 which corresponds to bits 11 0 being set to 1 Given the device classification addressing space and manufacturer of the HP E1357A E1358A multiplexers reading the ID Register returns FFFF16 An example of how to read the ID Register is found in the Programming Examples section later
105. hat the brackets are not part of the command and are not sent to the instrument Suppose you send a second level command but do not send the preceding implied command In this case the instrument assumes you intend to use the implied command and it responds as if you had sent it Examine the partial excerpt from the SENSe subsystem shown below SENSe FUNCtion lt function gt FUNCtion RESistance APERture time APERture MIN MAX NPLC number NPLC MIN MAX The root command SENSe is an implied command To set the multimeter s function to AC volts for example you can send either of the following command statements SENS FUNC VOLT AC or FUNC VOLT AC 66 Strain Gage Multiplexer Command Reference Chapter 5 Parameters Parameter Types The following table contains explanations and examples of parameter types you might see later in this chapter Parameter Type Explanations and Examples Numeric Accepts all commonly used decimal representations of number including optional signs decimal points and scientific notation 123 123E2 123 1 23E2 123 1 23E 2 1 23000E 01 Special cases include MIN MAX and DEF MIN selects minimum value available MAX selects maximum value available and DEF selects default or reset value Boolean Represents a single binary condition that is either true or false 1 or ON 0 or OFF Discrete Selects from a finite number of values These parameter
106. he specimen the guard shield must be connected to each channel to maintain the Wagner Ground This is because the guard G terminal on the relay multiplexers is switched to the multimeter in addition to the HI and LO bridge outputs see The Chevron Bridge on page 56 Chapter 4 Understanding the Strain Gage Multiplexers 57 Note When using the FET multiplexers with several strain gages on a single specimen only one guard lead needs to be connected since the guard is not switched with the HI and LO terminals Understanding the Bridge Configurations 1 4 Bridge Measurements QUARter Rosette Measurements This section describes each bridge configuration in detail In a V4 bridge arrangement there is one active element gage in the Wheatstone Bridge circuit Figure 4 8 A single strain gage has the lowest sensitivity of the bridge arrangements available however accurate measurements can still be made when following the wiring guidelines covered in Chapter 2 V4 bridge measurements are used when measuring strain with rosettes A three element rosette for example would be connected to three bridge completion channels Each channel would then be programmed for a V4 bridge measurement Each measurement 1 2 3 is then substituted into the applicable rosette equation in Appendix B Figure 4 8 1 4 Bridge Arrangement 58 Understanding the Strain Gage Multiplexers Chapter 4 1 2 Bridge I
107. his chapter uses this procedure Chapter 4 covers the procedure in detail 34 Making Strain Gage Measurements Chapter 3 Single Channel 1 4 Bridge Measurements Comments This program makes a 14 bridge strain measurement on channel 0 of multiplexer card number 1 Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Specify the gage factor for the channel measured OUTPUT 70903 STR GFAC 2 11E 6 100 Measure the channel s unstrained reference OUTPUT 70903 CAL STR 100 DISP Add tension to the specimen then press Continue PAUSE DISP n Measure the strain on the channel Enter and display the reading OUTPUT 70903 MEAS STR QUAR 100 ENTER 70903 Strn_rdg PRINT Strn_rdg END The wiring diagram used for this example is on page 28 e Specifying the gage factor as 2 11E 6 returns the strain measurement in microstrain A gage factor must be specified and an unstrained reference must be measured for each channel Chapter 3 Making Strain Gage Measurements 35 Multi Channel 1 4 Bridge Measurements This program makes 1 4 bridge strain measurements on channels 0 1 and 2 of multiplexer card number 1 Dimension a computer variable to store the strain measurements DIM Strn_rdgs 1 3 Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Specify the gage factor for each channel measured OUTPUT 70903 STR GFAC 2 11E 6 100 102 Measure the unstrain
108. his format is preceded by a header consisting of non zero digit block length In this program the header preceding the measurement data is 516000 The 5 represents the number of digits indicating the block length 16000 and 16000 is the block length 2 000 readings 8 bytes reading When HP BASIC is used the program s ENTER Dmm USING statement is used to remove the Arbitrary Block header tells the computer not to terminate the ENTER until all ENTER statements have completed X tells the computer to skip the first character of the Arbitrary Block header K K stores the non zero digit and block length portions of the header in the Ndig and Count variables respectively The ENTER Dmm Rags statement enters the readings into the computer Since a Line Feed LF follows the last reading ENTER Dmm removes the LF character from the multimeter output buffer If the LF character is not removed error 410 Query Interrupted occurs the next time data is sent to the buffer This third ENTER statement is only required when using the REAL data formats 38 Making Strain Gage Measurements Chapter 3 Rosette Measurements This program makes a rectangular rosette measurement on channels 0 1 and 2 of multiplexer card number 1 Dimension a computer variable to store the strain measurements DIM Strn rdgs 1 3 Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST Specify the
109. ical address 114 multiplexer card number 3 Logical address 115 multiplexer card number 4 Chapter 1 Getting Started with the Strain Gage Multiplexers 21 Multiplexer Channel The strain gage multiplexer channels within the scanning multimeter and Addresses switchbox are specified in the form ccnn single channel ccnn ccnn multiple channels ccnn ccnn sequential channels ccnn ccnn ccnn ccnn groups of sequential channels where cc is the card number and nn is the channel number For example 100 107 specifies channels 0 through 7 on multiplexer card number 1 The leading 0 in the card number can be omitted Chapter 3 contains example programs showing how a channel and channel list is specified in a strain measurement command The strain measurement commands are described in detail in Chapter 5 Connecting the ln scanning multimeter and switchbox instruments the multiplexers are Mu Itiplexe rs connected to the multimeter and to other multiplexers with an analog bus cable or with an analog bus cable and a digital bus cable Figure 1 6 The cables used are determined as follows 1 If the scanning multimeter or switchbox uses relay strain gage multiplexers only the analog bus cable is used 2 If the scanning multimeter or switchbox uses FET strain gage multiplexers only the analog bus cable and the digital bus cable are used 3 If the scanning multimeter or switchbox uses a combina
110. in Gage Excitation Maximum excitation voltage 45 4 V Appendix A HP E1355A E1356A E1357A E1358A Specifications 101 Maximum Voltage Terminal to Chassis 15V peak Connectors Used P1 input impedance less above 13V peak Number of Slots 1 Maximum Current per Channel 5 mA non inductive Maximum Offset Voltage 25 uV 0 to 28 C 250 uV 28 to 55 C differential High to Low Input Impedance Power On Vin lt 10V High to Low 10 80 High or Low to Chassis gt 1048Q Guard to Chassis 10 kQ 10 Capacitance High or Low to chassis 200pf High to Low 200pf Power Off High to Low for Vin lt 13V gt 1000Q for Vin gt 13V 22200 Closed Channel Resistance 3 1 kO for high or low input Guard not switched Bandwidth 3 dB 50Q source 1 MOIITOpf termination gt 500 kHz Low tied to chassis Screw Terminal Wire Size 16 AWG Max 26 AWG Min Module Size Device Type B register based Interrupt Level selectable Power Requirements Voltage 5V 412V Peak module current IPM A 0 53 0 13 Dynamic module current IDM A 0 01 0 01 Strain Gage Excitation chassis referenced 4 63V 10 Max Current 400mA short circuit protected Watts Slot 2 8 Cooling Slot 0 02 mm H20 0 10 liter sec Humidity 65 0 to 40 C Operating Temperature 0 to 55 C Storage Temperature 40 to 75 C EMC RFI Safety meets FTZ 1046 1984 CSA 556B IEC 348 UL 1
111. in this appendix The Device Type Register contains a model code which identifies the module base 0216 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Read Model Code Model Code Status Register Model Code The following model codes identify the HP E1357A and E1358A FET Strain Gage Multiplexers The model codes are set by the terminal module attached to the HP E1351 66201 component module or by the card ID switches on the component module FF1416 HP E1357A 8 Channel 120 FET Strain Gage Multiplexer FF1616 HP E1358A 8 Channel 350Q FET Strain Gage Multiplexer The FET multiplexer Status Register indicates if interrupts are enabled if an interrupt has occurred and if the multiplexer is busy closing or opening a channel base 0416 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Read FF 1 1 1 BSY 1 1 IRQ IRQ EN IRQ EN IRQ BSY Interrupt Request Enabled A zero 0 indicates enabled a one 1 indicates disabled Interrupt Request A zero 0 indicates an interrupt a one 1 indicates no interrupt This bit remains one 1 if IRQ EN is disabled Interrupt remains set until Card Reset or interrupt has been acknowledged Busy This bit is set zero 0 during channel closing and the delay period Triggers will not be accepted BSY is unasserted at the beginning of the channel closed pulse If
112. int E1 of the Wheatstone Bridge via the guard lead to the same potential as the specimen Because of this circuit the strain gage accessories are identified as having a driven guard Figure 4 7 The Wagner Ground When the strain gage Rg is mounted to the specimen there is generally thousands of Megohms of isolation resistance between the gage and the specimen If a difference in potential exists between the specimen and the midpoint of the bridge stray leakage currents are generated current voltage resistance These leakage currents in turn introduce random voltages along the measurement path which are then interpreted as strain related signals By keeping the potential on the specimen and the midpoint of the bridge the same leakage current is reduced In applications where the specimen is maintained at a specific potential by an external source the Wagner Ground will float set the midpoint of the bridge to the same potential For example if 100V is applied to the specimen and the bridge excitation voltage is 5 0V the E point on the Bridge is floated to 102 5V E2 is floated to 97 5V and the midpoint E1 is maintained at 100V The Wagner Ground circuit is only in effect when the guard lead is connected from the specimen to the G terminal on the bridge completion channel The guard lead will generally be the shield surrounding the conductors on a twisted shielded cable Note that if several gages are mounted to t
113. ions and Material Tables 105 Rosette and Biaxial Stress State Equations o e 105 Maternal TADS uoo xk Eos OK obo o E RORGORGOR UR ROUES ob OR B NOR OECOE ROC URGE 106 Appendix C Strain Gage Diagnostics o o e 107 About This Appendbe X K acad PRacRGRORGOR A de deed 107 Dispnoste Channels 24 00 04 4285008 Ecko RR ded RO A ROAD 107 Leadwie Resistance ok 24a RRR OO REOR RON CU D TRO 108 Leadwire Desensitization Corrections ee len 108 Internal Half Bridge Voltage cs i bea yee Ve EASE OE SO ROSE OR RO EORR REG 111 Shim ISTA NENRETETLOTETT ITI 1 7 57 97 2 1010 TV 113 Guard Vollage sooo o Wo AA AA A RI OES X ER 116 B dse Excitation Voltage a oa ek ek ob ae ab e depo de el p ecd 118 Appendix D Strain Gage Register Based Programming 119 About TIAS APES x css LEER BSH AUR a CR RECON e een 119 Resister Addressing uu uou b dde eR CR Bg deed de Me RR Oe ed a 120 Th Base AUGERE v uou quor eO OR e Re SES eR De cade 121 A16 Address Space Inside the Command Module or Mainframe 122 Regier uua daos RGR Re ci oded Ra ee Res 122 Resister DeSCHD UOBS cc kh GAR ORK SEED EE SEES OR o ROC EEE CR CU ES 123 Relay Multiplexer Seeger gt oo uo b RR RR X SOR OX RR E RO ACE AO ERE SOR 123 Th READ BEOSSS ura ge WEES Ee HES SEER ee ei 123 TD Tiro MP LITT 123 Device Type REST i e hoe E ELO OR ERG UOR de odio dog cR dob LO 124 DUIS OCI ouais qat Rok odd eai dei tpe E e
114. itch Figure 1 3 selects one of seven Interru pt Line interrupt lines used to communicate with the system s Slot 0 module Number In a scanning multimeter configuration see Strain Gage Multiplexer Configurations on page 19 the multiplexer s relay and FET do not use an interrupt line since communication is between the multimeter and the Slot 0 module In a switchbox configuration the multiplexers use an interrupt line At the factory the IRQ jumper or switch is set to line 1 Since the system instrument in the Series B mainframe is assigned to each line and the Series C command module E1406A is assigned line 1 by default it is not necessary to change the IRQ jumper switch setting If the command module in Series C systems is assigned another line and the switchbox is to use that line the IRQ jumper switch must be set accordingly To select another line de solder both jumpers and re solder them in the new positions HP E1345 66201 HP E1551 66201 LINE LINE 12 X 1 12 3 4 4 Aa 0 1 0 1 P 1 PENNA ioc RN Open CARD ID 5 9 12x 5 o 1 2 3 4 0 1 0 l Rn Koa 1 Ru o 1 o Open 0 12 X I l lu 3 oll pO San 6 a 1 Bv 1 Open HP E1355A E1356A HP E1357A E1358A 7 0 witch is set to the O position
115. ke sequence between the FET multiplexer switchbox and the voltmeter occurs over the multiplexer s digital bus When connected as shown in Figure 2 8 the digital bus cable HP Part Number E1411 80001 connects the multiplexer s channel advance and channel closed pins to the voltmeter s VM Compl and Ext Trig ports respectively Thus when a multiplexer channel is closed a channel closed pulse from the multiplexer is applied to the voltmeter s Ext Trig port When the voltmeter measurement is complete the voltmeter complete signal triggers the multiplexer via the channel advance line Continued on Next Page 44 Making Strain Gage Measurements Chapter 3 The FET multiplexer switchbox can be used with an external voltmeter without using the digital bus cable Connect the voltmeter to the switchbox as indicated in Figure 2 7 on page 31 However do not connect the cable between the voltmeter s voltmeter complete port and the mainframe s Event In port Modify the previous program as follows Configure the external multimeter for DC voltage measurements Configure its trigger system such that the multimeter is externally triggered when the Imultiplexer channel is closed OUTPUT 722 PRESET NORM OUTPUT 722 MEM FIFO OUTPUT 722 TBUFFON OUTPUT 722 TRIG EXT Configure the FET multiplexer switchbox so that it outputs a trigger pulse when a channel is closed Set the switchbox to be triggered by the TRG comman
116. l safety precautions must be observed during all phases of operation service and repair of this product Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the product Hewlett Packard Company assumes no liability for the customer s failure to comply with these requirements Ground the equipment For Safety Class 1 equipment equipment having a protective earth terminal an uninterruptible safety earth ground must be provided from the mains power source to the product input wiring terminals or supplied power cable DO NOT operate the product in an explosive atmosphere or in the presence of flammable gases or fumes For continued protection against fire replace the line fuse s only with fuse s of the same voltage and current rating and type DO NOT use repaired fuses or short circuited fuse holders Keep away from live circuits Operating personnel must not remove equipment covers or shields Procedures involving the removal of covers or shields are for use by service trained personnel only Under certain conditions dangerous voltages may exist even with the equipment switched off To avoid dangerous electrical shock DO NOT perform procedures involving cover or shield removal unless you are qualified to do so DO NOT operate damaged equipment Whenever it is possible that the safety protection features built into this product have been i
117. lications it may not be possible to measure unstrained references Vout Vs unstrained prior to making the actual strain measurements A feature of the strain gage multiplexers is the ability to measure unstrained references store the references in a computer and then download them at the time the strain measurements are made The following example shows how unstrained references are measured stored in a computer and then downloaded when the strain measurements are made Dimension computer variables to store the unstrained reference measurements land strain measurements DIM Unstr 0 2 Strn rdgs 0 2 Clear and reset the multimeter CLEAR 70903 OUTPUT 70903 RST With the specimen in an unstrained state call the subprogram which measures the unstrained references for each channel Store the references in a computer variable CALL Ref_meas Unsir Once the specimen is in a strained state the strain measurements can be made PAUSE Make three sets of strain measurements For each set specify the gage factor download the unstrained references and then measure the strain Enter and display the readings OUTPUT 70903 STR GFAC 2 11E 6 100 102 CALL Ref load Unstr FOR J 1 TO 5 OUTPUT 70903 MEAS STR QUAR 100 102 ENTER 70903 Strn_rdgs PRINT Stm rdgs NEXT J PRINT WAIT 5 OUTPUT 70903 STR GFAC 2 11E 6 91 00 102 CALL Ref load Unstr FOR J 1 TO 5 OUTPUT 70903 MEAS STR QUAR 100 102
118. list A trigger advances the scan through the channel list An invalid channel list generates an error see the ROUTe SCAN command e Stopping Scanning Cycles See the ABORt command Example Enabling a Single Scan SCAN 100 107 Sets channel list INIT Starts scanning cycle 76 Strain Gage Multiplexer Command Reference Chapter 5 MEASure The MEASure command subsystem is an HP E1326B E1411B Multimeter subsystem which configures the multimeter for strain measurements After configuring the multimeter MEASure immediately makes the strain measurement Executing MEASure is equivalent to configuring the multimeter with the low level commands shown in the following table Parameter Command Setting Range VOLTage RANGe As specified or autorange RESistance RANGe Resolution VOLTage RESolution As specified or as a function of range Aperture Time Integration Time Autozero Offset Compensation Trigger Source Number of Triggers or Number of Scans Trigger Delay Readings per Trigger Sample Period RESistance RESolution VOLTage APERture RESistance APERture VOLTage NPLC RESistance NPLC CALibration ZERO AUTO RESistance OCOMpensated TRIGger SOURce TRIGger COUNt TRIGger DELay SAMPle COUNt SAMPle SOURce integration time or aperture time 16 7 ms 60 Hz or 20 ms 50 Hz or based on specified resolution 1 power line cycle PLC or based on specified resolution ON au
119. loses bridge completion channel 1 0010 closes bridge completion channel 2 0011 closes bridge completion channel 3 0100 measures the leadwire resistance on bridge completion channel 0 0101 measures the leadwire resistance on bridge completion channel 1 0110 measures the lower leg of the internal half bridge voltage 0111 measures the upper leg of the internal half bridge voltage 1000 closes bridge completion channel 4 1001 closes bridge completion channel 5 1010 closes bridge completion channel 6 1011 closes bridge completion channel 7 1100 notused 1101 notused 1110 measures the guard voltage 1111 measures the bridge excitation voltage C1 CO Configuration bits These bits determine the measurement mode as listed below C1 CU 0 O Volts strain and diagnostic measurements 0 1 2 wire ohms B D A D Band Tree Isolation Switch disable A zero 0 in either one disables the respective Tree Isolation Switch Generally both disabled together to equal the SCAN PORT NONE command VLD Valid Channel A zero 0 indicates that the specified channel is valid When entering a scan list the entire list must be loaded into each multiplexer For the channels that are not on that multiplexer VLD must be set false Appendix D Strain Gage Register Based Programming 131 Direct Channel The Direct Channel Register allows you to specify channels to be closed Co nfigu ration individually Note that
120. low C1 CU 0 O Volts strain and diagnostic measurements 0 1 2 wire ohms B D A D Band A Tree Isolation Switch disable A zero 0 in either one disables the respective Tree Isolation switch Generally both disabled together to equal the SCAN PORT NONE command VLD Valid Channel A zero 0 indicates that the channel is valid The DIR bit in the Control Register automatically sets this bit If DIR is valid and IRQ EN is true a write to this register will generate an interrupt 132 Strain Gage Register Based Programming Appendix D Programming Examples The examples in this section demonstrate how to program a relay and FET multiplexer switchbox at the register level The examples include e Reading the ID Register e Reading the Device Type Register e Resetting the Switchbox e Measuring the Bridge Excitation Voltage e FET Multiplexer Scanning The programs assume the A16 address space is inside the HP E1300A E1301A mainframe HP E1405 E1406 Command Module and that the logical address of the switchbox is 112 The programs are written in Hewlett Packard BASIC and use the SCPI commands DIAGnostic PEEK and DIAGnostic POKE to read and write to the registers Reading the ID AS previously mentioned the ID Register indicates the classification Reg ister addressing mode and manufacturer of the device This program reads the ID Register and returns FFFF 6 Convert the switchbox base address to decimal and store the value in a variabl
121. m paired either through physical damage excessive moisture or any other reason REMOVE POWER and do not use the product until safe operation can be verified by service trained personnel If necessary return the product to a Hewlett Packard Sales and Service Of fice for service and repair to ensure that safety features are maintained DO NOT service or adjust alone Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DO NOT substitute parts or modify equipment Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the product Return the product to a Hewlett Packard Sales and Service Office for service and repair to ensure that safety features are maintained 8 HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual Declaration of Conformity according to ISO IEC Guide 22 and EN 45014 Manufacturer s Name Hewlett Packard Company Loveland Manufacturing Center Manufacturer s Address 815 14th Street S W Loveland Colorado 80537 declares that the product Product Name 8 Channel Strain Gage Multiplexer Module Model Number E1355A E1356A E1357A E1358A Product Options All conforms to the following Product Specifications Safety IEC 1010 1 1990 Incl Amend 1 1992 EN61010 1 1993 CSA C22 2 1010 1 1992 UL 1244 EMC CISPR 11 1990 EN55011 1991 G
122. ments FPOisson Poisson Full bridge measurements FBPoisson Bending Poisson Full bridge measurements QTENSsion Tension shunt diagnostic QCOMpression Compression shunt diagnostic UNSTrained Unstrain reference voltage measurement e The default strain function is QUARter V4 bridge measurements QTENsion and QCOMpression are used for relay strain gage multiplexers only Example Making 1 4 Bridge Strain Measurements STR GFAC 2 11E 6 100 103 Specify the gage factors for the channels CAL STR 100 103 Measure the unstrained references CONF STR QUAR 100 103 Configure the multimeter and make Va bridge measurements VOLT RANG MIN Set 0 125V range 72 Strain Gage Multiplexer Command Reference Chapter 5 DISPlay Subsystem Syntax MONItor CARD Parameters Comments Example The DISPlay subsystem monitors the state of the selected multiplexer channel This command can only be used when the relay or FET strain gage multiplexers are used in a switchbox configuration It operates with mainframes that have a display such as the HP 75000 Series B Mainframe HP Model Number E1301A It also operates with terminals connected to the serial interface port DISPlay MONItor CARD number AUTO STATe mode DISPlay MONitor CARD number AUTO selects the multiplexer in a switchbox to be monitored Parameter Name Parameter Type Range of Values number AUTO Numeric 1 99
123. mments Example The ABORt subsystem stops a scan in progress when the scan is enabled and the trigger modes are TRIGger SOURce BUS or TRIGger SOURce HOLD ABORt ABORt Operation For relay strain gage multiplexers ABORT invalidates the current channel list and sets ARM COUNT 1 one scanning cycle per INITiate command sets INITiate CONTinuous OFF no continuous scanning and sets TRIGger SOURce IMMediate continuous internal triggering For FET strain gage multiplexers ABORT resets the trigger system and places the multiplexer in the idle state The scanning parameters remain as previously set When a new trigger is received the scan begins at the beginning of the scan list Stopping Scans Enabled from Interface When a scan is enabled from the HP IB interface use an interface CLEAR command or the HP E1301 front panel Reset Instr or Clear Instr key to stop the scan When the scan is enabled from the HP IB interface and the trigger source is TRIGger SOURce BUS or TRIGger SOURce HOLD use ABORT or the HP E1301 front panel Reset Instr or Clear Instr keys to stop the scan Stopping Scans Enabled from Front Panel When a scan is enabled from the HP E1301 front panel execute RST over the interface or the front panel Reset Instr or Clear Instr keys to stop the scan Related Commands ARM INITiate CONTinuous ROUTe SCAN TRIGger Stopping a Scan with ABORt TRIG SOUR BUS Bus is trigger source INIT CONT ON Set con
124. mming 135 Convert the FET switchbox base address to decimal and store the value in a variable COM Base addr Base addr DVAL 1FDCO00 16 Set up the external voltmeter for DC voltage measurements external Itriggering and store the readings in voltmeter memory until all measurements have been taken OUTPUT 722 PRESET NORM OUTPUT 722 MEM FIFO OUTPUT 722 NPLC 1 OUTPUT 722 TRIG EXT OUTPUT 722 EXTOUT RCOMP NEG Call the subprogram which downloads the scan list sets the settling time and triggers the scan The unstrained references are measured on this scan CALL Fet scan Pause the program until stress is applied to the specimen Call the subprogram lagain to set up the scan for the strain measurements PAUSE CALL Fet scan Enter the unstrained references and strain measurements from the multimeter linto the computer Call the subprogram to compute the strain ENTER 722 Vout unstr Vs unstr Vout str Vs str CALL Strn_cmput Vr Vout str Vout unstr Vs str Vs unstr END Subprogram which sets up the scan list SUB Fet scan COM Base addr Clear old the scan list and set up the Scan Control Register for the next scan OUTPUT 70900 DIAG POKE Base_addr 6 16 H1 OUTPUT 70900 DIAG POKE Base_addr 6 16 HO Download the scan list Scan bridge output channels 0 1 2 and bridge lexcitation channel 15 OUTPUT 70900 DIAG POKE Base_addr 10 16 H6000 OUTPUT 70900 DIAG POK
125. n a Y bridge arrangement there are two active elements gages within the Measurements Wheatstone Bridge circuit Figure 4 9 The V5 bridge arrangement has twice the sensitivity as the V4 bridge arrangement and the additional strain gage compensates for temperature induced apparent strain The 2 bridge strain measurements available based on gage positioning on the specimen are described in the following sections E1355 fig4 9 Figure 4 9 1 2 Bridge Arrangement Bending 1 2 Bridge The maximum sensitivity achieved with a V bridge arrangement is when HBENding the strain gages are mounted to the specimen as indicated in Figure 4 10 When the beam is strained strain gage Rg1 will be strained in tension and strain gage Rg2 will be strained in compression When both gages are strained the same amount simultaneously the output of the bridge sensitivity is doubled Since the gages represent adjacent legs in the Wheatstone Bridge circuit any temperature induced strain is cancelled A g1 tension Rg2 compression E1355 fig4 10 Figure 4 10 Bending 1 2 Bridge Chapter 4 Understanding the Strain Gage Multiplexers 59 Poisson 1 2 Bridge In applications where there is no equal strain of opposite sign as there is for HPOisson the beam in Figure 4 10 an increase in measurement sensitivity and temperature compensation is achieved by mounting the strain gag
126. nding 51 Dummy Gage 60 Dynamic Strain Measurements 37 E Equations biaxial stress state 105 rosette 105 strain measurement 52 Error messages 137 138 numbers 137 138 queue 94 ESE 98 ESE 98 ESR 98 Examples dynamic strain measurements 37 FET strain gage measurements 43 45 measurements using external voltmeter 41 43 45 measurements with downloaded unstrained references 46 47 multi channel 1 4 bridge measurements 36 See also Program Examples relay strain gage measurements 41 rosette measurements 39 single channel 1 4 bridge measurements 35 single channel bending full bridge measurements 40 Excitation Voltage externally supplied 24 FET multiplexer 19 internally supplied 18 relay multiplexer 18 required for bridge 24 External Voltmeter connecting FET multiplexers to 32 connecting relay multiplexers to 31 FET strain gage measurements with 43 45 measurements using 63 relay strain gage measurements with 41 F FBENding bending full bridge 61 FBPoisson bending poisson full bridge 62 FET Multiplexer connecting to external voltmeter 32 control register 129 device type register 127 direct channel configuration register 132 direct control register 132 excitation voltage 19 ID register 126 identifying 15 measurements with an external voltmeter 43 45 registers 126 132 scan channel configuration register 131 scan channel delay register 128 130 scan control register
127. ned is calculated for each channel and is used with the channel s unstrained reference to determine Vr Note Vs unstrained and Vs strained is measured one time per channel list If the channel list includes more than one multiplexer Vs is measured one time on each multiplexer Downloaded The strain gage multiplexers have the capability of measuring the unstrained Unstrained eference voltages storing the references in a computer and then References downloading the references at the time the strain measurements are made This feature is useful in applications where repeated strain measurements are made once a single unstrained reference has been measured The commands to measure store and download the unstrained reference are CALibration STRain Ochannel_list measures the unstrained reference STRain UNSTrained channel list queries the references and returns them to the output buffer from where they are entered into the computer STRain UNSTrained reference Q channel list downloads the unstrained references An example of how unstrained references are downloaded is found on page 46 Chapter 4 Understanding the Strain Gage Multiplexers 51 Strain The equations in the instrument firmware which calculate the measured Measurement _ Strain are given in Table 4 1 Equations Table 4 1 Strain Measurement Equations Arrangement Equation Parameter V4 Bridge l e 4Vr GF 1 2Vr QUARter Poisson Ya Bridge
128. nnel list to scan and measure Close the first channel in the scan list and start the scan 84 Strain Gage Multiplexer Command Reference Chapter 5 SCAN MODE Parameters Comments Example SCAN MODE Example ROUTe SCAN MODE mode sets the multiplexer channels defined by the ROUTe SCAN channel list command for None Volts or 2 wire Ohms measurements Strain measurements with a relay or FET switchbox and an external multimeter require the SCAN MODE VOLT mode Parameter Name Parameter Type Range of Values mode Discrete NONE VOLT RES e Order of Command Execution The ROUTe SCAN MODE command must be executed before the ROUTe SCAN channel list and ROUTe CLOSe channel list commands e NONE and VOLT Mode Description Channel list is set up for voltage measurements This mode is required for strain measurements RES Mode Description Channel list is set up for 2 wire ohms measurements When making 2 wire measurements using the relay strain gage multiplexer the bridge selection jumper must be set to the FULL bridge position e RST Condition ROUT SCAN MODE NONE Selecting the Voltage Mode This example scans four channels for DC voltage measurements TRIG SOUR EXT Selects external trigger source SCAN MODE VOLT Selects the voltage scanning mode SCAN 100 102 115 Sets channel list INIT Starts scanning cycle ROUTe SCAN MODE returns the current state of the s
129. nnel number 00 15 includes internal channels For the FET strain gage multiplexers the channel list for CLOSe is in the form ccnn or in special circumstances ccnn ccnn where cc card number 00 99 and nn 2 channel number 00 15 includes internal channels Before using the CLOSe command with the FET multiplexers you must specify the SCAN MODE and SCAN PORT as these commands determine what tree switches will be closed on a given channel You can only have one channel closed on a FET multiplexer at a time If you want to close a channel on two different multiplexers in the same switchbox instrument e g 102 202 you can use ccnn ccnn Parameters Parameter Name Parameter Type Range of Values channel list Numeric cc00 cc15 Comments Closing Channels relay multiplexers To close asingle channel use CLOSe ccnn multiple channels use CLOSe ccnn ccnn sequential channels use CLOSe ccnn ccnn a group of sequential channels use CLOSe ccnn ccnn ccnn cenn 80 Strain Gage Multiplexer Command Reference Chapter 5 Closing Channels FET multiplexers To close asingle channel use CLOSe ccnn single channels on different cards use CLOSe ccnn ccnn Closure order for multiple channels with a single command is not guaranteed e Related Commands ROUTe JOPEN ROUTe CLOSe ROUTe SCAN MODE ROUTe SCAN PORT e RST Condition All multiplexer channels are open
130. nt might appear as OUTPUT 70903 OUTPUT 70914 Interface Select Code 7 Determined by the address of the HP IB interface card in the computer In most Hewlett Packard computers this card has a factory set address of 7 Primary HP IB Address 09 This is the address of the HP IB port on the Series B mainframe and on the Series C HP E1406A Command Module The mainframe and command module have a factory set address of 9 Secondary HP IB Address 03 14 This address is determined by dividing the logical address of the instrument identifier by 8 Thus fora scanning multimeter with an instrument identifier logical address of 24 the secondary address is 03 For a switchbox with an instrument identifier logical address of 112 the secondary address is 14 Multiplexer Card The multiplexer modules in a scanning multimeter and switchbox Numbers instrument assume card numbers within the instrument Figure 1 4 The multiplexer with the lowest logical address is card number 1 the next lowest logical address is card number 2 and so on Thus in the following configurations the multiplexer card numbers would be Scanning Multimeter Logicaladdress 224 multimeter Logicaladdress 225 multiplexer card number 1 Logicaladdress 226 multiplexer card number 2 Logicaladdress 227 multiplexer card number 3 Switchbox Logical address 112 multiplexer card number 1 Logical address 2 113 multiplexer card number 2 Log
131. ode DISP MON CARD 2 Selects multiplexer 2 in a switchbox DISP MON 1 Turns the monitor mode on 74 Strain Gage Multiplexer Command Reference Chapter 5 INITiate The INITiate subsystem selects continuous scanning cycles and starts the scanning cycle Subsystem Syntax INITiate CONTinuous mode CONTinuous IMMediate CONTinuous INITiate CONTinuous mode enables or disables continuous scanning cycles for the switchbox Parameters Parameter Name Parameter Type Range of Values mode Boolean 0 1 ON OFF Comments Continuous Scanning Operation Continuous scanning is enabled with the INITiate CONTinuous ON or INITiate CONTinuous 1 command Sending the INITiate IMMediate command closes the first channel in the channel list Each trigger from a trigger source selected by the TRIGger SOURce command advances the scan through the channel list A trigger at the end of the channel list closes the first channel in the list and the scan cycle repeats Scanning a Set Number of Cycles The INITiate CONTinuous OFF or INITiate CONTinuous 0 command goes through the scan list the number of times specified by the ARM COUNt command Sending the INITiate IMMediate command closes the first channel in the channel list Each trigger from a trigger source selected by the TRIGger SOURce command advances the scan through the channel list A trigger at the end of the channel list opens the last channel in the list and if
132. oisson ratio for the strain gage on the channel specified A poisson ratio must be specified for each channel when measuring poisson configurations Parameter Name Parameter Type Range of Values poisson_ratio Numeric as specified channel_list Numeric 00 07 One poisson ratio must be specified for each channel measuring a poisson configuration The poisson ratio must be specified before the strain is measured Specifying the Poisson Ratio STR POIS 32 100 Specifies the Poisson Ratio SENSe STRain POISson channel list returns the poisson ratio set for the channel specified Parameter Name Parameter Type Range of Values channel list Numeric 00 07 e Returned value is given in exponential notation e g 3 200000E 001 Querying the Poisson Ratio STR POIS 9100 Queries the poisson ratio for channel 0 Chapter 5 Strain Gage Multiplexer Command Reference 89 STRain UNSTrained Parameters Comments Example STRain UNSTrained Parameters Comments Example SENSe STRain UNSTrained reference channel list downloads a previously measured and stored unstrained reference voltage for the channel An unstrained reference must be specified for each channel Parameter Name Parameter Type Range of Values reference Numeric as measured channel list Numeric 00 07 e STRain UNSTrained downloads unstrained references that are
133. onfiguration bridge 58 strain gage multiplexer 19 terminal module 23 CONFigure Subsystem 71 72 99 CONFigure STRain 72 FBENding 72 FBPoisson 72 FPOisson 72 HBENding 72 HPOisson 72 QCOMpression 72 QTENsion 72 QUARter 72 UNSTrained 72 Conformity declaration 9 Connecting external voltmeter 31 32 full bridge arrangement 30 half bridge arrangement 29 multiplexers 22 quarter bridge arrangement 28 strain gages to multiplexers 23 32 34 Continuous Scans 75 Control Register FET multiplexer 129 relay multiplexer 125 writing to 135 Creating scanning multimeter 19 20 switchbox instrument 20 140 HP E1355A 56A 57A 58A Modules User s Manual Index D Declaration of conformity 9 Device Type Register FET multiplexer 127 model code 124 127 reading the 134 relay multiplexer 124 DIAGnostic PEEK 133 DIAGnostic POKE 133 Diagnostics 107 118 bridge excitation voltage 118 channels 107 guard voltage 116 internal half bridge voltage 111 leadwire resistance 108 shunt verification 113 Digital Bus cables 22 handshaking 87 triggering 96 Direct Channel Configuration Register FET multiplexer 132 Direct Control Register FET multiplexer 132 Discrete Command Parameters 67 DISPlay Subsystem 73 74 99 DISPlay MONitor CARD 73 DISPlay MONitor STATe 74 Documentation History 8 Downloaded Unstrained References example program 46 47 SCPI command 90 understa
134. ostics 111 supplied bridge excitation voltage 18 Interrupt Line 17 IRQ 17 J Jumpers bridge selection 24 55 card ID 14 excitation voltage 19 interrupt line IRQ 17 strain excitation 19 K Key words rules for use 66 L Leadwire Desensitization Corrections 108 Leadwire Resistance 27 diagnostics 108 Linking Commands 67 Logical Address multimeter 19 20 scanning multimeter 19 21 strain gage multiplexers 19 21 switchbox 20 21 Making continuous scans 75 strain gage measurements 33 48 strain measurements 49 135 Manufacturer ID Register address space 123 126 device class 123 126 FET multiplexer 126 manufacturer identification 124 127 reading the 133 relay multiplexer 123 Material Tables 106 MEASure Subsystem 77 78 99 MEASure STRain 78 FBENding 78 142 HP E1355A 56A 57A 58A Modules User s Manual Index FBPoisson 78 FPOisson 78 HBENding 78 HPOisson 78 QCOMpression 78 QTENsion 78 QUARter 78 UNSTrained 78 Measurements bridge excitation voltage 135 dynamic strain 37 FET strain gage measurements 43 45 full bridge 61 63 half bridge 59 60 multi channel 1 4 bridge 36 quarter bridge 58 relay strain gage measurements 41 resistance and voltage 64 rosette 39 58 single channel 1 4 bridge 35 single channel bending full bridge 40 strain 49 unbalanced bridge technique 50 using external voltmeter 63 voltage and resistance
135. peration is contained in the HP EI326B EI411B User s Manual Unbalanced Bridge The strain gage multiplexers measure strain using an unbalanced Measurement Wheatstone Bridge see Understanding the Strain Gage Measurement Techni que Circuits on page 53 Unbalanced bridge measurement techniques do not require the bridge to be balanced manually or electronically before strain measurements are made 50 Understanding the Strain Gage Multiplexers Chapter 4 Calculating Vr Residing in the instrument firmware are the equations used to calculate the measured strain Table 4 1 on page 52 One parameter common to each equation is Vr Vr is the difference in ratios of the Wheatstone Bridge output voltage Vout to the bridge excitation voltage V s under strained and unstrained conditions In equation form Vr is represented as Vr Vout V s strained Vout V s unstrained The strain measurement procedure involves measuring the voltages which determine Vr Once Vr is known the firmware calculates the value of strain When CALibration STRain channel list is executed the multimeter measures the unstrained bridge output voltage Vout and the bridge excitation voltage Vs and computes the unstrained reference Vout Vs for each channel When MEASure STRain strain function channel list is executed the multimeter measures the strained bridge output voltage Vout and the bridge excitation voltage Vs The ratio of Vout V s strai
136. pplicable to the command 1500 External trigger source already allocated Assigning an external trigger source to a switchbox when the trigger source has already been assigned to another switchbox 2000 Invalid card number Addressing a module card in a switchbox that is not part of the switchbox 2001 Invalid channel number Attempting to address a channel of a module in a switchbox that is not supported by the module e g channel 99 of a multiplexer module 2006 Command not supported Sending a command to a module card in a switchbox that is unsupported by the module 2008 Scan list not initialized Executing INIT command with no scan channel list 2009 Too many channels in channel list Attempting to address more channels than available in the switchbox 2010 Scan mode not allowed on this card Attempting to execute a SCAN MODE which is not supported 2011 Empty channel list No valid channels in channel list 2012 Invalid channel range Invalid channel s specified in SCAN lt channel_list gt command Attempting to begin scanning when no valid channel list is defined 2017 Incorrect ARM COUNt Attempting to run a downloaded scan list with ARM COUNt set to value other than 1 2600 Function not supported on this card Sending a command to a module card in a switchbox that is not supported by the module or switchbox
137. r The following WRITE registers are located on the FET strain gage multiplexer Control Register base 0416 e Scan Control Register base 0616 e Scan Channel Delay Register base 0816 e Scan Channel Configuration Register base 0A 16 e Direct Channel Configuration Register base 0C16 e Direct Control Register base OE16 The Control Register is used to reset the multiplexer enable interrupts choose direct or scan list control of the channels and to internally trigger channel closing base 0416 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined X X X TRG DIR IRQ X CRD INT EN RST CRD RST IRQ EN DIR TRG INT Card Reset Writing a one 1 to bit 0 resets the multiplexer Writing a Zero turns the reset function off You must write a zero after a reset or the multiplexer will not operate The Reset conditions are all enables are set false 0 clear scan list scan mode enabled direct bit set 0 delay is 1 usec and all channels opened Interrupt Request Enable Write A one 1 enables the card to generate interrupts a zero 0 disables it Direct Selects between direct control and scan list control A zero 0 indicates scan list control and a one 1 indicates direct control For scan list control the Direct Registers base OC base OE are invalidated For direct control the Scan Channel Configuration Register is inv
138. rations understanding 58 selection jumpers 24 55 wiring diagrams 25 Bridge Completion Channels 25 connecting strain gages to 27 wiring to 54 Bridge Excitation internally supplied voltage 18 measuring voltage 135 power requirements 24 voltage 18 24 voltage diagnostic 118 voltage requirements 24 voltage terminals 24 HP E1355A 56A 57A 58A Modules User s Manual Index 139 C Cables analog bus 22 digital bus 22 twisted shield 27 CALibration Subsystem 70 99 CALibration STRain 70 Card ID jumpers 14 ID switch 15 16 numbers 21 Certification 7 Channel address 22 bridge completion 25 27 closing 80 diagnostic 107 gage factor 88 opening 82 93 poisson ratio 89 register relay multiplexer 125 unstrained reference voltage 70 unstrained references 90 Chevron Bridge 56 circuit 56 Closing channels 80 tree relay 125 tree switches 86 CLS 98 Command Reference 65 100 Commands abbreviated 66 alphabetical listing 65 100 IEEE 488 2 65 98 implied 66 keyword 66 linking 67 optional 66 optional parameters 67 parameters 67 quick reference 99 SCPI 65 SCPI format 65 separator 66 types 65 Comment Sheet reader 11 Common Commands 65 CES 98 ESE 98 ESR 98 format 65 IDN 98 list of 98 OPC 98 OPC 98 quick reference 100 RCL 98 RST 98 100 SAV 98 SRE 98 SRE 98 STB 98 TRG 96 98 100 TST 98 100 W AT 98 C
139. ridge resistor V lower OUTPUT 70903 MEAS VOLT DC 91 10 ENTER 70903 V lower Measure the bridge output voltage Vout on channel 0 OUTPUT 70903 MEAS VOLT DC 100 ENTER 70903 Vout Measure the voltage on the leadwires V_leadwire OUTPUT 70903 MEAS VOLT DC 108 ENTER 70903 V_leadwire Compute the value of leadwire resistance 350 ohm gage assumed R_leadwire V_leadwire 350 V_lower Vout V_leadwire PRINT Leadwire resistance R_leadwire END A typical output from this program is Leadwire resistance 411719144 110 Strain Gage Diagnostics Appendix C Internal Half Bridge Voltage Specification Set Up CAUTION The Internal Half Bridge Voltage diagnostic accessed through internal channels 10 and 11 measures the voltage across the 1kQ internal half bridge resistors These measurements check the ratio of upper leg to lower leg bridge resistance The equations in the instrument firmware which calculate the actual strain measured allow for a certain amount of bridge imbalance due to differences in these resistances A voltage resistance ratio outside the tolerance causes a bridge imbalance not accounted for in the equations This results in inaccurate strain measurements Figure C 3 represents the internal half bridge resistors and where the measurements occur CVSZ T Ch 10 Vlow BR Reomp 120 OR SOC Figure C 3 Internal Half Bridge Measurements
140. rigger the multiplexer OUTPUT 722 PRESET NORM OUTPUT 722 MEM FIFO OUTPUT 722 TBUFFON OUTPUT 722 TRIG EXT OUTPUT 722 EXTOUT RCOMP NEG Configure the relay multiplexer switchbox so that it outputs a trigger signal via the mainframe Trig Out port when a channel is closed and so that it is externally triggered via the mainframe Event In port to close a channel Connect the analog bus which carries the bridge output and excitation voltages to the HI LO and Guard terminals on the multiplexer terminal module OUTPUT 70914 RST OUTPUT 70914 OUTP ON OUTPUT 70914 TRIG SOUR EXT OUTPUT 70914 SCAN PORT ABUS Download the scan list to measure Vout and Vs unstrained Close the first channel in the list to start the scan OUTPUT 70914 SCAN 100 102 115 OUTPUT 70914 INIT DISP Add tension to the specimen then press Continue PAUSE DISP nn Download the scan list to measure Vout and Vs strained Close the first channel in the list to start the scan OUTPUT 70914 SCAN 100 102 115 OUTPUT 70914 INIT Compute and display the 1 4 bridge strain measurements ENTER 722 Vout unstr Vs unstr Vout str Vs str CALL Strn cmput Vr Vout str Vout unstr Vs str Vs unstr END SUB Strn cmput Vr Vout str Vout unstr Vs str Vs unstr FOR I 1 TO 3 Vr l Vout_str l Vs_str Vout_unstr l Vs_unstr Epsilon l 4 Vr 1 2 11E 6 1 2 Vr 1 PRINT Epsilon l NEXT
141. roupl Class A IEC 801 2 1991 EN50082 1 1992 4kVCD 8k VAD IEC 801 3 1984 EN50082 1 1992 3 V m TEC 801 4 1988 EN50082 1 1992 1kV Power Line Supplementary Information The product herewith complies with the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 336 EEC and carries the CE marking accordingly Tested in a typical configuration in an HP B Size VXI mainframe July 20 1995 Ha QA Manager European contact Your local Hewlett Packard Sales and Service Office or Hewlett Packard GmbH Department HQ TRE Herrenberger Stra e 130 D 71034 B blingen Germany FAX 49 703 1 14 3143 HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual 9 Notes 10 HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual cut along this line Please fold and tape for mailing Reader Comment Sheet HP E1355A 56A 57A 58A Strain Gage Multiplexer Module User s Manual Edition 3 You can help us improve our manuals by sharing your comments and suggestions In appreciation of your time we will enter you in a quarterly drawing for a Hewlett Packard Palmtop Personal Computer U S government employees cannot participate in the drawing Your Name City State Province Company Name Country Job Title Zip Postal Code Address Telephone Number with Area Code Please list the system controller operating system programming language and plug in modules you are using
142. ry Scan Port This example selects the analog bus port then queries the state Because the analog bus port is selected the query command returns ABUS SCAN PORT ABUS Selects the ABUS port SCAN PORT Query the port selection 86 Strain Gage Multiplexer Command Reference Chapter 5 SETTling TIME RoUTe SETTIing TIME time channel list sets the delay between the multiplexer s receipt of a trigger command and the generation of the channel closed pulse The SETTling TIME command applies to the FET strain gage multiplexers only You must specify one and only one channel for each multiplexer in the switchbox instrument The time applies to all channels on the multiplexer The range is 1 usec to 32 768 usec Parameters Parameter Name Parameter Type Range of Values time Numeric 1E 6 32 768E 3 MIN MAX channel list Numeric only one channel Comments Using an External Voltmeter When using an external voltmeter with the FET strain gage multiplexer switchbox a voltmeter complete signal is often used to trigger the multiplexer to close a channel Because of the speed at which a FET channel closes the channel closed pulse often occurs before the multimeter is ready to make the measurement The SETTling TIME command delays the channel closed pulse until the voltmeter is ready Digital Bus Handshaking Operation of the digital bus is described in the AP E1326B EIA411B Multimeter User s Manual
143. s chapter describes Standard Commands for Programmable Instruments SCPI commands and summarizes IEEE 488 2 Common Commands applicable to the relay and FET strain gage multiplexers This chapter contains the following sections e Command Types 0 cece eee eee Page 65 e SCPI Command Reference nurru Page 67 e EEE 488 2 Common Commands s s s sssesene ssa Page 98 e Command Quick Reference 00 00 00 00005 Page 99 Commands are separated into two types IEEE 488 2 Common Commands and SCPI Commands The IEEE 488 2 standard defines the Common commands that perform functions like reset self test status byte query etc Common Commands are four or five characters in length always begin with the asterisk character and may include one or more parameters The command keyword is separated from the first parameter by a space character Some examples of Common commands are shown below RST ESR 32 STB The SCPI commands perform functions such as making measurements querying instrument states or retrieving data A command subsystem structure is a hierarchical structure that usually consists of a top level or root command one or more low level commands and their parameters The following example shows a typical subsystem CALibration LFRequency frequency LFRequency MIN MAX ZERO AUTO mode ZERO AUTO CALibration is the root command LFRequency LFRequency and ZERO are second level commands and A
144. s qo ege acoge ui ob Ba de Kb de e et 67 SCPI Command Reference 2 duo eee REOR GP bU oh a PEERED EES 67 rios pcc 68 AE o4 4444449444444 PS 4 A9 PELE SS SLED ESE EES SHE 69 erT Ue the eB IE hk a d oy eo 69 COUN srta og Re dba SHES Ee ORC SELENE OBA EERE 69 CAMINO ter we a ROS eR x SoSH ae RE RR AA 70 Coder RP X C TRITT 70 sas iUm C rmm 71 Hori MET Irc 72 2 HP E1355A 56A 57A 58A Modules User s Manual Contents DUER sy tt s e cgo dd a dea od se t a e Gc e oie e ea Ta IMONIOBCARD voi RAR a 93 OLS DOH ERR dede s T3 MONT STATS 4 ao thea te Ee AAN A A ARA 74 o ud ud deb uas do eee bi dq dread d Ned ded dud 75 Xd EDI AR AAA ta Ta COMME ins oh oe ee lada iE IER DESCR GE E ded ds 76 BI e T oud aOR EE RE AAA ECR 76 MESES 4 a a OA da abe de Ve cake ake th a Be TI SIRE irritada dia das a ed ORS DOES REE HRA 78 CHIEU coe wee A dE Ao s doe aS ES e E PRESS 79 ESTI o EEE A E E eee 79 E A 79 ROUT TI lt 4 seeks ados A A CR OEE de OR e ca al 80 A EC d Puedo e YR EOE EE ded he dex A Dew qq axe d 80 MIC C I 81 dU Jd A X 5 60 A TAER RARE E A A A A a E 82 OFEN 2 dabo eos 8264645 Rb Res acp Au do EORR Recte od 82 BL MN uou unas dedico dob i hk gh deor ote E b dee nbn e e ied obe o 83 SCANAMODILE a i kc Rok RA Qoae Ko ERE OSE pod de 85 SCAN MODE 4 45 4 0 obe WALT EL EOS EEE d v ORS Oe 4 85 AA A oe ee xD dq oS A 86 SCANSPORET ad a ee OR EDEL EEDES EK dep dede 86 BEI Tine TIME ak uk die Ke ok beo eR d dO OR D cl 87 SEUS pT ux dco d det R
145. s the internal channel and the diagnostic on that channel Table C 1 Strain Gage Multiplexer Diagnostic Channels Channel Diagnostic 8 9 Leadwire Resistance Channels 8 and 9 measure the voltage drop in the leadwires from the strain gage to the bridge completion circuit for bridge completion channels 0 and 1 From this voltage and the value of the bridge completion resistor the leadwire resistance can be determined so that leadwire desensitization corrections can be made 10 11 Internal Half Bridge Voltage Channels 10 and 11 measure the lower and upper legs of the internal half bridge voltage This checks the stability of the 1 0000 bridge completion resistors 12 13 Shunt Verification Channel 12 places a resistor in parallel with the bridge completion channel strain gage to simulate a known value of compressive strain Channel 13 places a resistor in parallel with the upper leg internal bridge resistor to simulate a known value of tensile strain 14 Guard Voltage Channel 14 measures the guard voltage Wagner Ground to determine if it is 1 2 of the bridge excitation voltage 15 Bridge Excitation Voltage Channel 15 measures the bridge excitation voltage Vs Appendix C Strain Gage Diagnostics 107 Leadwire Resistance Leadwire Desensitization Corrections Specification Set Up CAUTION The Leadwire Resistance diagnostic accessed through internal channels 8 and 9 enables
146. s use mnemonics to represent each valid setting An example is the TRIGger SOURce source command where source can be BUS DBUS EXT HOLD or IMM Optional Parameters Parameters shown within square brackets are optional parameters Note that the brackets are not part of the command and are not sent to the instrument If you do not specify a value for an optional parameter the instrument chooses a default value For example consider the ARM COUNt MIN MAX gt command If you send the command without specifying a parameter the present ARM COUNt value is returned If you send the MIN parameter the command returns the minimum count available If you send the MAX parameter the command returns the maximum count available Be sure to place a space between the command and the parameter Linking Commands Linking IEEE 488 2 Common Commands with SCPI Commands Use a semicolon between the commands For example RST OUTP ON Or TRIG SOUR BUS TRG Linking Multiple SCPI Commands Use both a semicolon and a colon between the commands For example ARM COUN 1 TRIG SOUR EXT SCPI Command Reference This section describes the Standard Commands for Programmable Instruments SCPI commands for the relay and FET strain gage multiplexer modules Commands are listed alphabetically by subsystem and also within each subsystem Chapter 5 Strain Gage Multiplexer Command Reference 67 ABORt Subsystem Syntax Co
147. scanning 75 creating 20 logical address 20 21 resetting 135 Switches card ID 15 16 interrupt line IRQ 17 logical address 20 tree 86 tree isolation 86 SYSTem Subsystem 92 94 99 SYSTem CDEScription 92 SYSTem CPON 93 SYSTem CTYPe 93 SYSTem ERRor 94 T Terminal Module bridge completion channels 25 27 bridge excitation voltage terminals 24 bridge selection jumpers 24 bridge wiring diagrams 25 configuration 23 H L G voltmeter terminals 25 identifying 14 wiring 26 Tree Switches closing 86 opening 82 register relay multiplexer 125 TRG 96 98 100 Trig Out Port 79 TRIGger Subsystem 95 97 100 TRIGger SOURce 95 96 BUS 95 96 DBUS 95 96 EX Ternal 95 96 HOLD 95 96 IMMediate 95 TRIGger SOURce 97 TRIGger IMMediate 95 TST 98 100 Twisted Shielded Cable 27 Two wire Ohms scanning mode 85 U Unbalanced Bridge Measurements 50 Understanding strain gage measurement circuits 53 strain gage multiplexers 49 64 the bridge configurations 58 Unstrained References downloaded 51 90 measurements with downloaded 46 47 measuring 70 Using bus triggers 97 example programs 33 external triggers 96 multiplexers in VXIbus system 14 twisted shielded cables 27 146 HP E1355A 56A 57A 58A Modules User s Manual Index V Voltage and resistance measurements 64 bridge excitation 18 24 135 internal half bridge 111 scanning mode 85 terminals bridge e
148. source is changed the external trigger source is available to another switchbox with a TRIGger SOURce EXTernal command Using Bus Triggers To trigger the switchbox with TRIGger SOURce BUS selected use TRIGger IMMediate the IEEE 488 2 common command TRG or the HP IB Group Execute Trigger GET command Trig Out Port Shared by Switchboxes See the OUTPut command Related Commands ABORt ROUTe SCAN SET Tling TIME TRIGger e RST Condition TRIGger SOURce IMMediate Examples Scanning Using External Triggers In the following example the trigger input is applied to the HP E1300 E1301 Mainframe s Event In port TRIG SOUR EXT Sets trigger source to external SCAN 100 107 Sets channel list INIT Starts scanning cycle trigger externally Advances channel list to next channel 96 Strain Gage Multiplexer Command Reference Chapter 5 Scanning Using Bus Triggers TRIG SOUR BUS Sets trigger source to bus SCAN 100 107 Sets channel list INIT Starts scanning cycle TRG Advances channel list SOURce TRIGger SOURce returns the current trigger source for the switchbox Command returns either BUS DBUS EXT HOLD or IMM for trigger sources BUS DBUS EXTernal HOLD or IMMediate respectively Example Query Trigger Source TRIG SOUR EXT Sets trigger source to external TRIG SOUR Query trigger source returns EXT Chapter 5 Strain Gage Multiplexer Command Reference 97 IEEE 488 2 Common Comm
149. ssification Bits 15 and 14 classify a device as one of the following memory device extended device message based device register based device 0A0 The HP E1355A E1356A multiplexers are register based devices Addressing Mode Bits 13 and 12 indicate the addressing mode used by the device A16 A24 address mode A16 A32 address mode RESERVED A16 address mode k O k GO The HP E1355A E13564 Relay Strain Gage Multiplexers use the A16 address mode Appendix D Strain Gage Register Based Programming 123 Manufacturer Manufacturer ID Bits 11 through 0 identify the manufacturer of the Identification device Hewlett Packard s ID number is 4095 which corresponds to bits 11 0 being set to 1 Given the device classification addressing space and manufacturer of the HP E1355A E1356A multiplexers reading the ID register returns FFFF16 An example of how to read the ID Register is found in the Programming Examples section later in this appendix Device Type The Device Type Register contains a model code which identifies the Register device base 0216 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Read Model Code Model Code Model Code The following model codes identify the HP E1355A and E1356A Relay Strain Gage Multiplexers The model codes are set by the card ID jumpers located on the E1345 66201 component assembly FF0416 HP E1355A 8 Channel 1200 Rela
150. sured several 5 10 times and the variance of the measurements is determined An increase in the variance indicates deteriorating performance Number of Operations Relays can be replaced after a predetermined number of contact closures However this method requires knowledge of the applied load and life specifications for the applied load The replacement strategy depends on the application If some relays are used more often or at a higher load than the others the relays can be individually replaced as needed If all the relays see similar loads and switching frequencies the entire circuit board can be replaced when the end of relay life approaches The sensitivity of the application should be weighed against the cost of replacing relays with some useful life remaining Relays that wear out normally or fail due to misuse should not be considered defective and are not covered by the product s warranty Appendix A HP E1355A E1356A E1357A E1358A Specifications 103 Notes 104 HP E1355A E1356A E1357A E1358A Specifications Appendix A Appendix B Strain Gage Equations and Material Tables Rosette and Biaxial Stress State Equations Rosette Equations Rectangular Rosette Biaxial Stress State Equations Ox Qu ee 10901 2 Oy Ox Ey E VE The following equations are used to calculate the strain measured with a three element rectangular or delta rosette Rosette measurements are covered in Chapter 4
151. tation voltage VS and the precision internal half bridge resistors R1 R2 of the bridge completion circuitry to be shared among all channels Because the multiplexers use an unbalanced bridge for strain measurements see Unbalanced Bridge Measurement Technique on page 50 the accuracy of the measurement depends on the resistance of the bridge arms remaining constant The resistance must remain constant for the unstrained measurement and the strain measurement The only resistance which changes is the resistance of the active gage s MULTIMETER VIA ANALOG BUS Figure 4 6 The Chevron Bridge The Chevron Bridge ensures that the bridge arm resistance remains constant by switching the outputs of the bridge completion channels HI high LO low G guard to the input of the multimeter By switching the outputs rather than switching the bridge arms the gages are permanently wired to the bridge completion channels via the E E1 and E2 terminals This eliminates any resistance changes due to self heating and variations in switch or relay contact resistance Note G guard is not switched on the FET multiplexers 56 Understanding the Strain Gage Multiplexers Chapter 4 The Wagner Ground To increase measurement accuracy the relay strain gage multiplexers contain a Wagner Ground circuit similar to that shown in Figure 4 7 The purpose of the Wagner Ground is to reduce stray leakage currents by driving the midpo
152. te below Note These commands apply to many instruments and are not documented in detail here See the HP 75000 Series B E1300 E1301 Mainframe User s Manual or the ANSI IEEE Standard 488 2 1987 for more information 98 Strain Gage Multiplexer Command Reference Chapter 5 Command Quick Reference The following tables summarize SCPI and IEEE 488 2 Common Commands for the Relay and FET Strain Gage Multiplexers SCPI Commands Quick Reference Command Command Parameter Description Subsystem ABORt ABORt Abort a scan in progress ARM COUNt number MIN MAX Multiple scans per INIT command COUNE MIN MAX Query number of scans CALibration STRain channel list Multimeter command measures the unstrained reference voltage on the strain measurement channel specified CONFigure STRain strain function channel list Multimeter command configures the multimeter for strain measurements DISPlay MONitor CARD lt number gt AUTO Selects module to be monitored MONItor STATe mode Selects monitor mode INITiate CONTinuous mode Enables Disables continuous scanning CONTinuous Queries scanning state IMMediate Starts a scanning cycle MEASure STRain strain function channel list Multimeter command configures the multimeter and makes the specified strain measurement OUTPut STATe mode Enables Disables Trig Out pulse
153. the A16 address space is outside or inside the HP E1405 E1406 Command Module or HP E1300 E1301 Mainframe When the Command Module or mainframe is not part of your VXIbus system Figure D 1 the multiplexer s base address is computed as C00016 LADDR 64 16 Or 49 152 LADDR 64 where C00016 49 152 is the starting location of the register addresses LADDR is the multiplexer s logical address and 64 is the number of address bytes per V XIbus device For example the multiplexer s factory set logical address is 112 With this address the multiplexer has a base address C00016 112 64 16 C00016 1C0016 DC0016 or decimal 49 152 112 64 49 152 7 168 56 320 1 The 16 at the end of the address indicates a hexadecimal number Appendix D Strain Gage Register Based Programming 121 A16 Address Space Inside the Command Module or Mainframe Register Offset When the A16 address space is inside the command module or mainframe Figure B 2 the multiplexer s base address is computed as 1FCO00016 LADDR 64 16 or 2 080 768 LADDR 64 where 1FC00016 2 080 768 is the starting location of the VXI A16 addresses LADDR is the multiplexer s logical address and 64 is the number of address bytes per register based device Again the multiplexer s factory set logical address is 112 If this address is not changed the multiplexer will have a base address of 1FC00016 112 64 16 1FC0001
154. tinuous scanning SCAN 100 107 Sets channel list INIT Starts scanning cycle ABOR Aborts scan in progress 68 Strain Gage Multiplexer Command Reference Chapter 5 ARM Subsystem Syntax COUNt Parameters Comments Example COUNt Parameters Comments Example The ARM subsystem selects the number of scanning cycles 1 through 32767 for each INITiate command This command does not apply to downloaded FET multiplexer scan lists For downloaded scan lists use the INIT CONT ON command for multiple scans ARM COUNt lt number gt MIN MAX COUNt MIN MAX ARM COUNt lt number gt MIN MAX allows scanning cycles to occur a multiple of times 1 to 32767 with one INITiate command Parameter Name Parameter Type Range of Values number Numeric 1 32767 MIN MAX Number of Scans Use only values between 1 to 32767 for the number of scanning cycles default is 1 Downloaded Scan Lists ARM COUNt does not apply to downloaded FET multiplexer scan lists e Related Commands ABORt INITiate IMMediate RST Condition ARM COUNt 1 Setting Ten Scanning Cycles ARM COUN 10 Set 10 scanning cycles SCAN 100 107 Sets channel list INIT Starts scanning cycle ARM COUNt MIN MAX returns current number of scanning cycles set by ARM COUNt ARM COUN MIN returns the minimum allowable parameter 1 and ARM COUN MAX returns the maximum allowable parameter 32767 Parameter Name
155. tion of relay and FET multiplexers only the analog bus cable is used e Analog bus Digital bus cable cable MULTIMETER MODULE MN py ely c EE E c ll QJ oooo MULTIPLEXER MODULES Connect cable s between multimeter N Casey dose and multiplexer and between multiplexers M E Figure 1 6 Connecting the Analog and Digital Bus Cables Descriptions of the analog bus and digital bus cables are found in the HP E1326B E1411B Multimeter Manual 22 Getting Started with the Strain Gage Multiplexers Chapter 1 Chapter 2 Connecting Strain Gages to the Multiplexers About This Chapter This chapter explains how the strain gage multiplexer terminal module is configured for measurements and how V4 V5 and full bridge configurations are connected to the terminal module The sections of this chapter are e Terminal Module Configuration Page 23 e Wiring a Terminal Module Page 26 e Strain Gage Wiring Diagrams l l esee Page 27 Terminal Module Configuration The strain gage terminal module used with each multiplexer accessory is shown in Figures 2 1A and 2 1B The terminal module is used to select the bridge arrangement on each channel e supply the bridge excitation voltage external source
156. tozero is performed after every measurement OFF resistance measurements only IMM trigger signal is always true Measurement is taken when multimeter goes to trigger state 1 number of triggers issued or number of scans through channel list before multimeter returns to idle state AUTO delays are 0 seconds for DC voltage and resistance 0 5 seconds for AC voltage 1 number of measurements taken when trigger is received IMM period between measurements or the period between FET multiplexer scans Subsystem Syntax MEASure Refer to Chapter 5 in the HP E1326B E1411B Multimeter User s Manual for more information on the MEASure subsystem STRain lt strain_function gt channel list Chapter 5 Strain Gage Multiplexer Command Reference 77 STRain MEASure STRain strain function 17 channel list measures strain using the specified bridge arrangement on the specified channel Parameters Parameter Name Parameter Type Range of Values strain function Discrete QUARter HBENding HPOisson FBENding FPOisson FBPoisson QTENsion QCOMpression UNSTrained channel list Numeric 00 07 Comments The strain measurements specified by the strain_function parameter are QUARter V4 Bridge measurements HBENding Bending 1 Bridge measurements HPOisson Poisson V Bridge measurements FBENding Bending Full Bridge measurements FPOisson Poisson Full
157. ultimeter and switchbox follow In a scanning multimeter instrument signals measured by the HP E1326B E1411B Multimeter are input via the multiplexer channels Channel openings and closings are controlled by the multimeter through commands sent to the multimeter To create a scanning multimeter instrument The instrument must have one module the multimeter assigned as the instrument identifier The instrument identifier is the module with a logical address that is a multiple of 8 8 16 24 The HP E1326B E1411B Multimeter has a factory set logical address of 24 The modules in the scanning multimeter instrument must have successive logical addresses beginning with the logical address of the multimeter For example with a multimeter logical address of 24 the logical addresses of the multiplexers must be 25 26 and so on The strain gage multiplexers have a factory set logical address of 112 The logical address is changed using the logical address switches shown in Figure 1 5 Chapter 1 Getting Started with the Strain Gage Multiplexers 19 Creating a Switchbox In a switchbox instrument signals are routed switched to a voltmeter Instrument external to the HP 75000 Series B or Series C mainframe Multiplexer channel openings and closings are controlled by the user through commands sent directly to the switchbox A switchbox instrument is created as follows The instrument must have one module multiplexer assigne
158. xcitation 24 unstrained reference 70 Voltmeter connecting external 31 32 H L G terminals 25 measurements with external 41 43 45 63 Vr calculating 51 VXIbus System using multiplexers in 14 W Wagner Ground 57 circuit 57 WAL 98 WARNINGS 8 Warranty 7 Wheatstone Bridge circuit 54 55 reducing loop area 27 Wire gage 27 106 resistance solid copper 106 Wiring considerations 27 full bridge arrangement 30 half bridge arrangement 29 quarter bridge arrangement 25 28 strain gage multiplexers 27 32 terminal module 26 to bridge completion channels 54 using twisted shielded cable 27 wire gage 27 WRITE registers channel register 125 control register 125 129 direct channel configuration register 132 direct control register 132 FET multiplexers 129 132 relay multiplexers 125 scan channel configuration register 131 scan channel delay register 130 scan control register 130 tree switch register 125 HP E1355A 56A 57A 58A Modules User s Manual Index 147
159. y Strain Gage Multiplexer FF0616 HP E1356A 8 Channel 350Q Relay Strain Gage Multiplexer Status Reg ister The relay strain gage multiplexer Status Register is monitored to determine when the multiplexer has finished opening or closing a channel base 0416 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Read FF BSY 1 1 1 1 1 1 1 BSY Busy A one 1 in bit 7 indicates the relay multiplexer is ready to receive a command A zero 0 in bit 7 indicates the multiplexer is busy closing or opening a channel 124 Strain Gage Register Based Programming Appendix D The WRITE The following WRITE registers are located on the relay strain gage Registers multiplexers Control Register base 0416 Tree Switch Register base 0616 Channel Register base 0816 Control Reg ister The Control Register on the relay strain gage multiplexer is used to reset the multiplexer to its power on state all channels open base 0416 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Write Undefined CRD RST CRD RST Card Reset Writing a one 1 to bit 0 resets the multiplexer to its power on state While bit 0 is 1 the multiplexer continually resets Tree Switch The relay multiplexer s Tree Switch Register controls tree relays 93 92 91 Register md 90 base 0616 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
160. you to determine the resistance of the leadwires from the strain gage to the bridge completion channel terminals The bridge completion channels on which this diagnostic is performed are channels 0 and 1 The leadwire resistance diagnostic is used for V4 bridge arrangements only When the leadwire resistance 1s known leadwire desensitization corrections can be made to the measured strain values Leadwire desensitization is the measurement error caused by the leadwire resistance Correction for leadwire desensitization is achieved by multiplying the measured strain value by the quantity 1 RI Rg In equation form this appears as e actual measured x 1 RI Rg where measured is the measured V4 bridge strain RI is the leadwire resistance and Rg is the resistance of the strain gage 120Q or 3500 There is no specification for leadwire resistance however typical values can range from a few tenths of an ohm to several ohms Among the factors that will affect leadwire resistance are wire gage wire length and temperature To perform the leadwire resistance diagnostic your system should be configured as follows 1 If the bridge excitation voltage is externally supplied connect the supply to the terminal module as shown in Figure C 1 Set the voltage to 5 0V 2 Connect the V4 bridge arrangement to bridge completion channel 0 Figure 2 4 on page 28 3 Place the specimen in a constant preferably unstrained state

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