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U ser’s G uide

P ublicat ion Nu mber 34970-90003 (order as 34970-90101 m anual set )Ed ition 3, Mar ch 2003

© Copyr ight Agilent Technologies, In c. 1997-2003

For Sa fety informa tion, Wa rra nties, and Regulat ory informa tion,see the pag es follow ing th e Index.

Agilent 34970A

D a t a Acquist ion /Sw itch U nit

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The Agilent Technologies 34970A combines precision mea surem entcapa bility w ith flexible signa l connections for your production an ddevelopment test syst ems. Three module slots a re built into th e rear

of th e instrument t o accept a ny combinat ion of dat a a cquisit ion orswit ching modules. The combinat ion of da ta logging a nd da taa cquisit ion feat ures ma kes t his instrument a versati le solution for yourtesting requirements n ow a nd in the future.

Convenient Data Logging Features

• D irect m easu rement of th ermocouples, RTD s, therm istors, dc volta ge,a c volta ge, resista nce, dc current , a c current, frequency, an d period

• Int erva l sca nning w ith st orage of up to 50,000 time-sta mped reading s

• Independent cha nnel configurat ion w ith function, Mx+ B scaling,a nd a larm limits a vailable on a per-cha nnel ba sis

• Int uitive user interfa ce w ith knob for quick cha nnel selection,menu navigat ion, a nd dat a entry f rom t he f ront panel

• P orta ble, ruggedized ca se with non-skid feet

• BenchL in k Data L ogger Software for Microsoft ® Windows ® included

Flexible Data Acquisition / Switching Features

• 61 ⁄ 2-digit mult imeter a ccura cy, sta bility , a nd n oise rejection

• U p to 60 cha nnels per inst rument (120 single-ended cha nnels)

• Rea ding ra tes up to 600 rea dings per second on a single cha nnel a ndscan ra tes up to 250 cha nnels per second

• Ch oice of multiplexing, m a tr ix, general-purpose Form C sw itching,RF sw itching, digita l I/O, tota lize, a nd 16-bit a na log output fun ctions

• G P IB (IE EE -488) interface and R S-232 interfa ce are st a nda rd

•SCPI (Standar d Commands for Pr ogrammable Instr uments ) compatibility

Agilent 34970A

D a t a Acquisition /Sw itch U nit

Note: Unl ess otherw ise in di cated, thi s manu al appli es to all seri al num bers.

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The Front P a nel a t a G lance

1 State Storage / Remote Interface Menus2 Scan Start / Stop Key3 Measurement Configuration Menu4 Scaling Configuration Menu5 Alarm / Alarm Output Configuration Menu6 Scan-to-Scan Interval Menu7 Scan List Single Step / Read Key

8 Advanced Measurement / Utility Menus

9 Low-Level Module Control Keys10 Single-Channel Monitor On / Off Key11 View Scanned Data, Alarms, Errors Menu12 Shift / Local Key13 Knob14 Navigation Arrow Keys

Denotes a menu key. See th e next page for detai l s on m enu operat ion.

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The Front -P a nel Menus at a G la nce

Severa l of th e front-pan el keys guide you th rough m enus t o configureva rious para meters of the inst rument (see previous pa ge). The followingsteps demonstra te the menu structure using the key.

T i p : To r evi ew th e cur r ent confi gur ati on of a speci fi c menu , press th e menu key sever al ti mes.A message NO CHANGES i s displayed w hen you exit th e menu .

4 P ress the same menu key aga in to accept t he chan ge a nd exit the menu. A brief confirmation

messa ge is displa yed.

2 P ress the same menu key aga in to moveto th e next item of the menu. Typica lly,

th is is w here you choose par a meter va lues for th e selected opera tion.

3 Rota te th e knob to view t he choices on th is level of th e menu. When you rea ch th e end

of th e list, rota te t he knob in t he opposite direction to view a ll of th e other choices.

The cur rent selecti on i s hi ghl ighted for emphasis. Al l other choices are dimmed.

1 P ress the menu key. You are a utoma tically guided to th e first level of th e menu. Rota te th e knob to view th e other choices on th e first level of th e menu.

The menu w il l au tomatically timeout afterabout 20 seconds of inacti vi ty. You wi l l be

retu rned t o the operati on i n progress pri orto ent er in g the menu .

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D isplay Annun ciat ors

To revi ew th e di spl ay ann un cia tors, hold down th e key as you

tur n on the in str um ent.

SCANMONVIEW

CONFIG ADRSRMTERROREXTONCEMEMLAST

MINMAXSHIFT4WOC

Scan is in progress or enabled. Press and hold again to turn off.Monitor mode is enabled. Press again to turn off.Scanned readings, alarms, errors, or relay cycles are being viewed.

Channel configuration is in progress on displayed channel.Measurement is in progress.Instrument is addressed to listen or talk over the remote interface.Instrument is in remote mode (remote interface).Hardware or remote interface errors are detected. Press to read errors.Instrument is configured for an external scan interval.Scan Once mode is enabled. Press to initiate and hold key to disable. Reading memory overflow; new readings will overwrite the oldest readings.Viewed data is the last reading stored during most recent scan.

Viewed data is the minimum reading stored during most recent scan.Viewed data is the maximum reading stored during most recent scan.

has been pressed. Press again to turn off.4-wire function is in use on displayed channel.Offset compensation is enabled on displayed channel.Alarms are enabled on displayed channel.Mx+B scaling is enabled on displayed channel.HI or LO alarm condition has occurred on indicated alarms.

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The Rea r P a nel a t a G la nce

WARNINGFor pr otecti on f r om electr ical shock, th e power cor d gr ound must not be

defeated. I f onl y a tw o-contact electr ical out let i s avail able, conn ect th e

i nstr um ent ’s chassi s ground scr ew (see above) to a good ear th ground .

1 Slot Identifier (100, 200, 300)

2 Ext Trig Input / Alarm Outputs / Channel Advance Input / Channel Closed Output (for pinouts, see pages 83 and 128)3 RS-232 Interface Connector

4 Power-Line Fuse-Holder Assembly

5 Power-Line Voltage Setting6 Chassis Ground Screw

7 GP-IB (IEEE-488) Interface Connector

Use the Menu to:

• Select the GP-IB or RS-232 interface (see chapter 2). • Set the GP-IB address (see chapter 2). •

Set the RS-232 baud rate, parity, and flow control mode (see chapter 2).

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B enchLink Da ta Logger S of twa re at a G lance

Agil ent B enchLi nk Dat a L ogger is a Windows-ba sed a pplica tiondesigned to ma ke it easy to use th e 34970A w ith y our P C for ga theringa nd a na lyzing mea surements. Use the softw a re to set up your test ,

a cquire an d a rchive mea surement da ta , an d perform rea l-time displaya nd a na lysis of your incoming mea surements.

B enchLink Da ta Logger’s key functions include the follow ing:

• Configure mea surement s on the spread sheet-like Scan Setu p page.

• Display m easurements g ra phica lly using t he real-time Data Gri d ,Str ip Chart , Readout , Bar M eter , XY Pl ot , and Histogram w indow s.

• Add or configure gra phics a t a ny t ime.

• U se gra phica l controls to set output volta ges, close chan nels, outputdigita l values, or view a larm s.

• Copy mea surement da ta a nd gra phics to a f i le or to the C lipboard foruse in oth er applica tions.

• Add textua l annota tion and expla na tions to measurement results a nd

test reports.• Tra ck rea dings on a single cha nnel through t he Monitor toolba r.

• En ter informa tion into the Event L og a utomatica l ly or manua l lywh ile acquiring mea surement da ta or during post-scan a na lysis.

• P rint scan setups, event logs, an d gra phics.

• Communica te w ith t he instrument using G P IB , RS-232, modem,or LAN (using a LAN-to-GPIB gateway).

To i nstall the softw ar e, refer to “I nstall in g BenchLi nk Dat a L ogger

Softw ar e” on page 18.

To lear n m ore about th e softwar e and it s capabi li ti es, refer to the

On-L in e H elp System for BenchL in k D ata L ogger .

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The P lug-In Modules a t a G la nce

For compl ete specifi cati ons on each pl ug-in modu l e, r efer to th e modul e

secti ons in chapt er 9.

34901A 20-Channel Armature Multiplexer

• 20 channels of 300 V switching

• Tw o chan nels for D C or AC current measurements (100 nA to 1A)

• Built-in thermocouple reference junction

• S w itching speed of up to 60 cha nn els per second

• Connects t o the internal multimeter

• For d etai led in form ati on and a modu l e di agram , see page 164.

Ea ch of th e 20 cha nnels switches both H I and LO inputs, th us providingfully isolat ed inputs t o the int erna l multimet er. The module is dividedinto tw o ba nks of 10 tw o-w ire cha nnels ea ch. When m a king four-w ireresista nce measurements, channels from Bank A a re automat ica l ly

paired with chann els from Bank B . Tw o additional fused cha nnels a reincluded on the module (22 channels total) for making calibrated D C orAC current mea surements w ith th e interna l multimeter (externa l shuntresistors a re not requ ired). You can close multiple chan nels on th ismodule only if you ha ve not configured a ny cha nnels to be pa rt of thescan list. Oth erw ise, all cha nnels on th e module a re break-before-ma ke.

34902A 16-Channel Reed Multiplexer

• 16 channels of 300 V switching

• Built-in thermocouple reference junction

• S w itching speed of up to 250 cha nnels per second

• Connects t o the internal multimeter

• For d etai led in form ati on and a modu l e di agram , see page 166.

U se this module for high-speed scann ing a nd high-th roughputa utoma ted test a pplica tions. Ea ch of the 16 cha nnels switches bothH I and LO inputs, th us providing fully isolat ed inputs to th e interna lmult imeter. The module is divided into t w o banks of eight tw o-w irecha nnels each. When ma king four-w ire resista nce measurements,chan nels from Bank A ar e automa tically pa ired with cha nnels fromBank B . You can close multiple cha nnels on t his module only i f you ha venot configured any cha nnels to be part of the scan list. Oth erwise, all

channels on the module are break-before-make.

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34903A 20-Channel Actuator / General-Purpose Switch

• 300 V, 1 A a ctua tion a nd sw itching

• SP DT (Form C) lat ching relays

• B readboard a rea for custom circuits

• For detai led inf ormati on and a modul e di agram , see page 168.

U se this module for th ose a pplica tions th a t require high-integrit ycont a cts or q ua lity connections of non-mult iplexed sign a ls. This m odulecan sw itch 300 V, 1 A (50 W ma ximum sw itch pow er) to your deviceunder test or t o actuat e externa l devices. Screw termina ls on t he moduleprovide a ccess t o th e Norma lly-Open, Norm a lly-Closed, a nd Comm oncont a cts for each of the 20 sw itches. A brea dboard a rea is provided nearth e screw t ermina ls to implement custom circuitr y, such as simplefilters, snubbers, or volta ge dividers.

34904A 4x8 Two-Wire Matrix Switch

• 32 tw o-w ire crosspoint s

• Any combinat ion of inputs a nd outputs can be connected a t a t ime

• 300 V, 1 A swit ching


U se this m odule to connect m ultiple instr ument s to mult iple point s onyour device under test a t t he sa me time. You can connect r ow s a nd

columns betw een multiple modules to build la rger ma trices such a s8x8 a nd 4x16, with up to 96 crosspoint s in a single ma infra me.

34905/6A Dual 4-Channel RF Multiplexers

• 34905A (50Ω) /34906A (75Ω)

• 2 G Hz ba ndw idth w ith on-boa rd S MB conn ections

• 1 G Hz bandwidth w i th S MB -to-B NC a da pter cables provided


These modules offer w ideband sw itching capa bilities for high frequencya nd pulsed signa ls. Ea ch m odule is organized in tw o independent ba nksof 4-to-1 multiplexers. B oth m odules offer low crosst a lk a nd excellentinsertion loss performa nce. To crea te la rger RF mult iplexers, y ou ca ncascade multiple ba nks together. Only one channel in each ba nk ma y be

closed at a t ime.

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In This B ook

Quick Start Cha pter 1 helps you get familiar w ith a few of theinst rument ’s front-pan el feat ures. This cha pter a lso shows h ow toinsta l l the BenchLi nk Dat a L ogger softw are.

Front-Panel Overview Ch a pter 2 intr oduces you to th e front-pan elmenus a nd describes some of th e inst rum ent’s menu fea tur es.

System Overview Cha pter 3 gives an overview of a da ta a cquisit ion

system a nd describes how pa rts of a syst em w ork together.

Features and Functions Ch a pter 4 gives a deta iled description of th einstrument’s capabilities and operation. You will find this chapteruseful wh ether you are operat ing th e instrument from th e front panel orover th e remote interfa ce.

Remote Interface Reference Ch a pter 5 cont a ins reference

informa tion to help you program the inst rument over th e remoteinterface using the S C P I l anguage.

Error Messages Cha pter 6 l ists the error messages tha t may a ppeara s you a re working w ith t he instrument. Ea ch l isting conta ins enoughinforma tion to help you dia gnose an d solve th e problem.

Application Programs Cha pter 7 contains severa l remote interfa ce

program exam ples to help you develop progra ms for your a pplica tion.

Tutorial Cha pter 8 discusses measurement considera tions a ndtechniques t o help you obta in th e best a ccura cies an d reduce sources ofmeasurement noise.

Specifications Ch a pter 9 lists the technical specificat ions for themainframe and plug-in modules.

I f you have questi ons rela ti ng t o the oper ati on of t he 34970A,

call 1-800-452-4844 i n t he Un i ted Stat es, or contact your near est

Agi l ent Technologi es Sales Off i ce.

I f your 34970A fai ls wi thi n th r ee years of origi nal pur chase, Agil ent w il l

eit her r epai r or r epl ace i t f r ee of char ge. Cal l 1-877-447-7278 and ask

for “Expr ess Exchange” or cont act your local Agil ent offi ce.

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Contents

Chapter 1 Quick Start

To P repar e th e In str ument for Use 17

Inst alling B enchLink Da ta Logger Softwa re 18

To Conn ect Wiring t o a Module 20

To Set th e Time a nd Da te 22

To Configure a Ch a nnel for Scann ing 23

To Copy a Cha nnel Configura tion 25

To Close a Cha nnel 26

If the Inst rument D oes Not Turn On 27

To Adjust the Ca rry ing Ha ndle 29To Ra ck Mount th e Inst rum ent 30

Chapter 2 Front-Panel Overview

Front -P a nel Menu Reference 35

To Monitor a S ingle Cha nnel 37

To Set a Sca n Int erval 38To Apply Mx+ B Sca ling to Measur ements 39

To Configure Ala rm Limits 40

To Read a Digital Input P ort 42

To Write to a Digit a l Output P ort 43

To Rea d the Tota lizer Count 44

To Output a DC Volta ge 45

To Configure th e Remote Interfa ce 46

To St ore the Inst rument Sta te 48

Chapter 3 System Overview

Da ta Acquisition System Overview 50

Signa l Routing a nd Sw itching 57

Measurement Input 60

Contr ol Output 67

C on t en t s

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Chapter 4 Features and Functions

SCP I La nguage Conventions 73

Scanning 74

Single-Ch a nnel Monitoring 93

Scanning With Ext ernal Instr uments 95

G enera l Measurement Configurat ion 98

Temperat ure Measur ement Configura tion 106

Volta ge Measur ement Configura tion 113

Resista nce Measur ement Configura tion 115

Current Mea surement Configuration 116

Freq uency Measur ement Configura tion 118

Mx+ B Scaling 119

Alar m Limit s 122

Digita l Input Opera tions 133

Tota lizer Opera tions 135

Digita l Output Opera tions 138

DAC Output Operat ions 139

Sy stem-Rela ted Operat ions 140Remote Int erface Configura tion 150

Ca libra tion Overview 155

Fa ctory Reset St at e 160

Instrument P reset Sta te 161

Multiplexer Module Defa ult Settin gs 162

Module Overview 163

34901A 20-Ch a nnel Mult iplexer 164

34902A 16-Ch a nnel Mult iplexer 16634903A 20-Ch a nnel Actu a tor 168

34904A 4x8 Ma tr ix S w itch 170

34905A/6A D ua l 4-Ch a nn el RF Mul t iplexers 172

34907A Multifun ction Module 174

34908A 40-Ch a nnel Sin gle-E nded Mult iplexer 176

C o n t e n t s

Contents

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Chapter 5 Remote Interface Reference

SCP I Command Summa ry 181

Sim plified P rogra mm ing Overview 201

The MEASure? a nd CONF igure Comma nds 207

Set ting the Funct ion, Ra nge, a nd Resolution 214

Temperat ure Configura tion Comma nds 219

Volta ge Configura tion Comma nds 223

Resistance Configurat ion Comma nds 224

Current Configuration Comma nds 224

Frequency Configurat ion Comma nds 225

Sca nning Overview 226

Single-Cha nnel Monitoring Overview 237

Scann ing With a n Ext ernal Instrument 239

Mx+ B Scaling Overview 244

Ala rm Sy stem Overview 247

Digita l Input Comma nds 255

Tota lizer Comma nds 256

Digita l Output Comma nds 258DAC Output Comma nds 258

Sw itch Control Comman ds 259

St a te St ora ge Comma nds 261

Syst em-Related Comma nds 264

Int erface Configura tion Comma nds 269

RS -232 Int erface Configura tion 270

Modem Commun ications 274

The SCP I St at us Syst em 275Sta tus System Commands 286

Ca libra tion Comma nds 292

Service-Relat ed Comma nds 294

An Introduction to the SCP I Langua ge 296

U sing Device Clea r 302

Chapter 6 Error Messages

Execution Er rors 305

Inst rument Err ors 309

Self-Test E rr ors 314

Ca libra tion Err ors 315

P lug-In Module Er rors 317

C

on t en t s

Contents

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Chapter 7 Application Programs

Exa mple P rogra ms for Excel 7.0 321

Example P rograms for C and C+ + 328

Chapter 8 Tutorial

Syst em Ca bling and Connections 335

Measurement Funda menta ls 343

Low-Level Signa l Multiplexing 378

Actuat ors an d General-P urpose Sw itching 384

Mat rix Sw itching 388

RF Signa l Multiplexing 390

Mult ifunct ion Module 392

Relay Life an d P reventa tive Maintena nce 399

Chapter 9 Specifications

DC , Resista nce, a nd Temperat ure Accura cy Specifications 404

DC Measur ement an d Opera ting Cha ra cteristics 405

AC Accura cy Specificat ions 406

AC Mea surement an d Opera ting Chara cteristics 407

Measurement Ra tes a nd Syst em Cha ra cteristics 408

Module Specificat ions 409

B enchLink Dat a Logger Softw a re Specifications 412P roduct a nd Module Dim ensions 413

To Ca lcula te Tota l Measur ement Err or 414

Int erpreting Int erna l DMM Specifica tions 416

Configuring for Highest Accura cy Measur ements 419

Index

C o n t e n t s

Contents

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1

Quick S t a rt

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Quick St a rt

One of the f irst things you will wa nt t o do with your instrum ent is tobecome a cqua inted w ith t he front pan el. We have w ritt en the exercisesin this cha pter to prepare th e instrument for use a nd help you getfa miliar w ith some of its front-pan el opera tions.

The front pa nel ha s severa l groups of keys to select va rious functionsa nd operat ions. A few keys ha ve a shifted function printed in blue below

th e key. To perform a shift ed function, press (th e SHIFT annunciator

w ill tur n on). Then, press the key th a t ha s th e desired label below it.For exam ple, to select th e U tility Menu, press .

If you a ccidenta lly press , just press it a ga in to tur n off th e SHIFTannunciator.

This cha pter is divided into t he following sections:

• To Prepare t he Inst rument for U se, on page 17

• Insta l ling B enchLink Da ta Logger S of twa re, on page 18

• To Conn ect Wiring to a Module, on page 20

• To Set t he Time a nd D a te, on page 22

• To Configure a C ha nnel for Sca nnin g, on page 23

• To Copy a Channel Configuration, on page 25

• To Close a C ha nn el, on page 26

• I f th e Instrum ent D oes Not Turn On, on page 27

• To Adjust th e Ca rrying H a ndle, on page 29

• To Rack Mount the I nstrum ent, on page 30

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To P repa re the Inst rum ent for U se

1 Check the list of supplied items.

Verify th a t you ha ve received the following i tems w ith y our instr ument.If anything is missing, contact your nearest Agilent Technologies Sales Office.

One power cord.

This User ’s Gui de .

One Servi ce Gui de .

One Qu ick Refer ence Gu i de .

Cer tifica te of Ca libra tion (if you ordered the interna l DMM).

Quick St a rt P a cka ge (i f you ordered the interna l DMM):

• One RS-232 cable.

• B enchLink Da ta Logger Softwa re CD -ROM.

To in sta l l th e softw ar e, see page 18.

• One J -ty pe th ermocouple a nd a flat blade screwd river.

Any plug-in modules tha t you ordered a re delivered in a separa te

shipping cont a iner.

2 Connect the power cord and turn on the instrument.

The front-pan el display w ill light up briefly while th e instrum entperforms its power-on self-test . The G P I B add ress is also displayed.The instrument init ial ly powers up w ith a l l measurement chan nelstur ned off. To review th e power-on display w ith a ll a nnun cia tors

turn ed on, hold dow n a s you turn on the instrument. I f the i nstr um ent does not t ur n on pr oper l y, see page 27.

3 Perform a comp le te self-test.

The complete self-test perform s a m ore extensive set of tests t ha n t hose

performed a t pow er-on. Hold down a s you tu rn on th e instr umentand hold down th e key unt i l you hear a l ong beep . The s elf-tes t w ill beginw hen you release th e key follow ing th e beep.

I f th e sel f-test fa i l s, see th e 34970A Ser vi ce Gu i de for i nstr ucti ons on

r etu rn in g the instrument to Agil ent for servi ce.

On/StandbySwitch

WARNING

Note that t hi s swi tchi s S t andby only.T o di sconnect th e

main s from the i nstr ument, removeth e power cord .

1

pTo Prepare the Instrument for Use

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Inst a l ling B enchLink Da ta Logger Softw a reIf you ordered th e 34970A w ith t he int erna l D MM , then the B enchLinkDa ta Logger softw a re is included. The softw a re is shipped on oneCD-ROM , but includes a ut ility t o build insta llat ion floppy disks.To inst a ll the softw a re on your P C , you will need a minimum of 12 MBof free disk spa ce.

For system requi r ement s and add i ti onal d etai l s on the featu r es of th e

softwar e, refer t o th e specifi cati ons i n chapt er 9.

Installation Procedure

I f you a r e r un n i ng Win dows 95 or W ind ows NT 4.0 ®

1. Insert the CD-ROM int o your drive.

2. Select Settings | Control Panel from the Start menu. Double-click on the Add/Remove Programs icon.

3. Select th e Install/Uninstall ta b on the Add/Remove Programs property sheet. Click on Install a nd follow th e on-screen in str uctions.

I f you a r e r u n n i n g Wi n dows ® 3.1

1. Insert the CD-ROM int o your drive.

2. Select File | Run f rom the P rogram Mana ger menu bar .

3. Type :\setup, wh ere dr ive is the letter representing yourCD -ROM drive. Click OK t o cont inue a nd follow th e on-screen

instructions.

Installing BenchLink Data Logger Software

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Creating Installation Floppy Disks

You ha ve the option to crea te a n inst a llat ion on floppy disks from theCD-ROM insta llat ion ut ility . This ut ility is provided so tha t you caninsta l l B enchLink Da ta Logger on a computer tha t does not have aCD-ROM drive.

No t e : You wi ll need a total of five (5) form att ed fl oppy di sks to cr eate an i nstal l at ion.

1. G o to a computer tha t is equipped w ith a CD-ROM drive.

2. St a rt th e insta llat ion procedure as described on th e previous page.

3. Select Create disks... on the initial display of the insta l la tionprocedures a nd follow th e on-screen instr uctions.

On-Line Help System

The softw a re is shipped w ith a n extensive on-line Help system to helpyou learn t he fea tures of th e softw a re as w ell as t roubleshoot a nyproblems th a t m ight a rise a s you a re using the softw a re. As you areinst a lling th e softw a re, you will notice tha t t he on-line H elp syst em isa vailable in severa l la ngua ges.

1

Installing BenchLink Data Logger Software

19

Chapter 1 Quick StartT C t Wi i t M d l

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To Connect Wirin g t o a Module

6 mm

20 AWG Typical

Channel Number:

Slot Channel

5 Inst a l l th e module into ma inframe. Wi r i n g H i n t s...

• For detailed information on each module,refer to the section starting on page 163.

• To reduce wear on the internal DMM relays,wire like functions on adjacent channels.

• For information on grounding and shielding, see page 335.

• The diagrams on the next page show how toconnect wiring to a multiplexer module foreach measurement function.

1 Rem ove th e module cover. 2 Connect w iring t o the screw t erminals.

4 Replace the module cover.

Cable Tie Wrap(optional)

3 Route w iring through stra in relief.

To Connect Wiring to a Module

20

Chapter 1 Quick StartTo Connect Wiring to a Module

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DC Voltage / AC Voltage / FrequencyThermocouple

Thermocouple Types: B, E, J, K, N, R, S, TSee page 351 for thermocouple color codes.

Ranges: 100 mV, 1 V, 10 V, 100 V, 300 V

4-Wire Ohms / RTD2-Wire Ohms / RTD / Thermistor

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 MΩRTD Types: 0.00385, 0.00391Thermistor Types: 2.2 k, 5 k, 10 k

Channel n (source) is automatically paired withChannel n+10 (sense) on the 34901A orChannel n+8 (sense) on the 34902A.

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 MΩRTD Types: 0.00385, 0.00391

DC Current / AC Current

Valid only on channels 21 and 22 on the 34901A.Ranges: 10 mA, 100 mA, 1A

1

To Connect Wiring to a Module

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Chapter 1 Quick StartTo Set the Time and Date

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To S et t he Time a nd D a t eAll readings during a sca n a re aut oma tically t ime sta mped and st oredin non-volat i le memory. In a ddition, ala rm da ta is t ime sta mped a ndstored in a s epara te non-vola tile memory queue.

1 Set the time of day.

U se a nd to select the f ield to modify a nd turn the knob to changeth e value. You can a lso edit the AM/P M field.

2 Set the date.

U se a nd to select the f ield to modify a nd turn the knob to changethe va lue.

Utility

Utility

To Set the Time and Date

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Chapter 1 Quick StartTo Configure a Channel for Scanning

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To Configure a Ch a nnel for S ca nningAny chan nel tha t can be “rea d” by the instrum ent can a lso be includedin a scan. This includes rea dings on multiplexer cha nnels, a rea d of adigita l port , or a read of the count on a tota l izer cha nnel. Automa tedscanning i s not al low ed with th e RF multiplexer, mat rix, actuat or,digita l output , or volta ge output (DAC) modules.

1 Select the channel to be added to the scan list.Turn t he knob unt il the desired cha nnel is shown on t he right s ide offront-pan el display . The cha nnel num ber is a th ree-digit num ber;th e left-most digit r epresent s th e slot n umber (100, 200, or 300) a nd t hetw o digits on the right indica te th e cha nnel number (102, 110, etc.).

No t e : You can use and to ski p to th e begin ni ng of the pr evi ous or next slot.

For th is exa mple, assum e tha t you ha ve the 34901A mult iplexerinst a lled in slot 100 a nd select cha nnel 103.

2 Select the measurement parameters for the selected channel.

U se the knob to scroll through t he mea surement choices on ea ch level

of th e menu. When you press to ma ke your selection, th e menu

a ut omat ica lly guides you through a ll relevant choices to configure amea surement on the selected function. When you ha ve finishedconfiguring t he para meters, you a re a utomat ica lly exited from the menu.

The current selection (or default ) is displa yed in full bright for ea syidentifica tion. When you ma ke a different selection, t he n ew choice isshow n in full bright a nd it becomes the defa ult selection. The order ofthe choices alwa ys rema ins the sam e; however, you a lwa ys enter the

menu a t t he current (full bright) sett ing for each pa ra meter.

No t e : The menu w il l ti meout after about 20 seconds of i nacti vi ty and any chan ges made pr evi ously w il l tak e effect.

For t his exam ple, configure chan nel 103 to mea sure a J -type t hermocouplewith 0.1 °C of display resolut ion.

1

To Configure a Channel for Scanning

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Chapter 1 Quick StartTo Configure a Channel for Scanning

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No t e : Pr ess to sequent i al ly step th r ough th e scan l ist and tak e a

measur ement on each channel (readi ngs are not stor ed i n memor y).Thi s is an easy way to ver if y your w ir in g conn ecti ons before in it i ati ng

th e scan .

3 Run the scan and store the readings in non-volatile memory.

The instrument a utoma tica lly scans th e con fi gur ed channels i n consecut i ve ord er from slot 100 th rough s lot 300 (th e SCAN a nnunciatorturns on). Cha nnels tha t a re not configured a re skipped during the scan.

In t he defa ult configurat ion, th e instrument continuously sca ns t heconfigured cha nn els at a 10-second interva l.

Pr ess and hol d to stop th e scan .

4 View the data from the scan.

All readings ta ken during a scan a re automa tically t ime sta mped a nd

stored in non-vola tile memory. During th e sca n, th e instrum entcalculat es and stores the minimum, ma ximum, and a verage on a llchannels in the scan l ist . You can rea d th e contents of memory a t a nytime, even during a sca n.

From th e front panel, data is ava ila ble for th e last 100 readings on eachchannel readings ta ken during a sca n (a ll of th e dat a is ava ila ble fromth e remote int erface). From th e View menu , select READINGS a nd press

a ga in. Then press a nd to choose the da ta you w a nt to viewfor t he selected chan nel as shown in th e ta ble below .

and

Select Channel Last Reading on Channel Time of Last ReadingMinimum Reading on Channel

Time of Minimum ReadingMaximum Reading on Channel Time of Maximum ReadingAverage of Readings on ChannelSecond Most Recent Reading on ChannelThird Most Recent Reading on Channel

99th Most Recent Reading on Channel

o Co gu e a C a e o Sca g

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Chapter 1 Quick StartTo Copy a Channel Configuration

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To Copy a Ch a nn el Configura t ionAfter configuring a chan nel to be included in t he scan list, you ca ncopy tha t sa me configuration to other cha nnels in the instrum ent(including digit a l cha nnels on t he mult ifunction m odule). This feat urema kes it ea sy t o configure several chann els for th e sam e measurement.When you copy the configura tion from one cha nn el to anoth er, thefollowing para meters a re a utoma tically copied to the new cha nnel:

•Measurement configurat ion

• Mx+ B sca ling configuration

• Ala rm configura tion

• Advanced measurement configuration

1 Select the channel to copy the configuration f r om .

Turn t he knob unt il the desired cha nnel is shown on t he right s ide offront-pan el displa y. F or this exam ple, let’s copy t he configura tion fromchan nel 103.

2 Select the copy function.

U se the knob to scroll through t he mea surement choices unt il you see

COPY CONFIG. When you press to ma ke your selection, th e menua utoma tically guides you to th e next step.

3 Select the channel to copy the configuration t o .

Turn t he knob unt il the desired cha nnel is shown on t he right s ide offront-pan el display . For t his exa mple, let’s copy th e configurat ion t ochan nel 105.

4 Copy the channel configuration to the selected channel.

Note : To copy the same conf igurati on to other channels, repeat th is procedu re.

1

py g

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Chapter 1 Quick StartTo Close a Channel

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To Close a Ch a nn elOn t he multiplexer an d sw itch modules, you ca n close an d open individualrela ys on t he module. However, note tha t i f you ha ve already configureda ny m ultiplexer cha nnels for sca nnin g, you ca nnot independent ly closea nd open individual relays on t ha t m odule.

1 Select the channel.

Turn t he knob until th e desired chan nel is shown on t he right side offront-pan el displa y. F or this exam ple, select chan nel 213.

2 Close the selected channel.

3 Open the selected channel.

No t e : wi ll sequenti al l y open al l chann els on t he modul e in the sel ected slot.

The t a ble below sh ows th e low-level cont rol operat ions a va ilable forea ch of the plug-in modu les.

Plug-In Module ,

34901A 20-Channel Mux • • • •

34902A 16-Channel Mux • • • •

34908A 40-Channel Single-Ended Mux [1] • • • •

34903A 20-Channel Actuator • •

34904A 4x8 Matrix • •

34905A Dual 4-Channel RF Mux (50Ω) [2] •

34906A Dual 4-Channel RF Mux (75Ω) [2] •

34907A Multifunction Module (DIO) • • •

34907A Multifunction Module (Totalizer) • •

34907A Multifunction Module (DAC) •

[1] Onl y one chan nel can be closed a t a ti m e on th is modul e.

[2] Onl y one chan nel in each bank can be closed a t a ti me on th is modul e.

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Chapter 1 Quick StartIf the Instrument Does Not Turn On

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If t he Inst rum ent D oes Not Turn OnU se th e follow ing st eps to help solve problems you might encount erw hen turn ing on the instrum ent. I f you need more help, refer t o the34970A Ser vi ce Gui de for instructions on returning t he instrument toAgilent for service.

1 Verify that there is ac power to the instrument.

First , verify th a t t he pow er cord is firmly plugged int o the pow errecepta cle on t he rear pa nel of the instr ument . You should also ma kesure th a t t he pow er source you plugged the instrum ent int o isenergized. Then, verify tha t t he instru ment is t urned on.

The On/ Standby swi tch is located on the lower left sid e of the fr ont panel.

2 Verify the power-line voltage setting.The line volta ge is set to the proper va lue for your count ry w hen t heinstrument is shipped from the fa ctory. Cha nge the volta ge setting i fit is not correct . The s ett ings a re: 100, 120, 220, or 240 Vac.

No t e : For 127 Vac oper ati on, use th e 120 Vac sett i ng.For 230 Vac operat i on, use th e 220 Vac sett i ng.

See th e next page if you need to change th e l i ne vol tage sett i ng.

3 Verify that the power-line fuse is good.

The instr ument is shipped from t he fa ctory w ith a 500 mA fuse insta lled.This is the correct fuse for all line voltages.

See th e next page i f you need t o repla ce th e power -l i ne fuse.

To replace the 500 mAT, 250 V fuse, order Agi lent par t number 2110-0458.

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Chapter 1 Quick StartIf the Instrument Does Not Turn On

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1 Remove th e power cor d . Remove thefuse-holder a ssembly from th e rear pan el.

2 Remove the line-voltage selector fromthe assembly.

3 Rota te t he line-volta ge selector until th ecorrect volta ge appea rs in the w indow.

4 Replace the fuse-holder a ssembly inthe rear pa nel.

Verify that the correct line voltage is selected and the power-line fuse is good.

Fuse: 500 mAT (for all line voltages)

Agilent Part Number: 2110-0458

100, 120 (127), 220 (230) or 240 Vac

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Chapter 1 Quick StartTo Adjust the Carrying Handle

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To Adjust th e Ca rry ing H a ndleTo a djust th e position, gra sp the ha ndle by the sides a nd pul l outward .Then, rota te t he ha ndle to th e desired position.

Bench-top viewing positions Carrying position

1

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Chapter 1 Quick StartTo Rack Mount the Instrument

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To Rack Mount t he Inst rum entYou can m ount th e instr ument in a sta nda rd 19-inch ra ck ca binet usingone of thr ee optiona l kits a vailable. Instructions a nd m ountingha rdw a re a re included wit h each ra ck-mounting kit. Any Agilent System I I instrument of th e sa me size can be ra ck-mount ed beside the 34970A.

No t e : Remove the car r ying handl e, and the fr ont and r ear r ubber bumpers,before r ack-moun ti ng the in str um ent .

To remove the handle, rotate it to the vertical position and pull the ends outward.

Front Rear (bottom view)

To remove the rubber bumper, stretch a corner and then slide it off.

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To rack mount two instruments side-by-side, order lock-link kit 5061-9694 andflange kit 5063-9212. Be sure to use the support rails inside the rack cabinet.

To install one or two instruments in a sliding support shelf, order shelf 5063-9255,and slide kit 1494-0015 (for a single instrument, also order filler panel 5002-3999).

To rack mount a single instrument, order adapter kit 5063-9240.

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Front-Panel

Overview

2

Fr ont -P a nel Overview

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Fr ont P a nel Overview

This cha pter int roduces you to the front-pan el keys a nd m enu opera tion.This cha pter does not give a deta iled description of every front -pan elkey or menu opera tion. It does, how ever, give you a good overview of th efront-pan el menu a nd ma ny front-pan el opera tions. See cha pter 4“Fea tu res an d Fun ctions,” sta rt ing on pa ge 71, for a complete discussionof the instrument’s capabilities and operation.

This cha pter is divided into t he following sections:

• Front -P a nel Menu Reference, on page 35

• To Monitor a S ingle Cha nnel, on page 37

• To Set a Scan Int erval , on page 38

• To Apply Mx+ B Sca ling to Mea surement s, on page 39

• To Configure Alar m Limit s, on page 40

•To Read a Digita l Input P ort , on page 42

• To Write to a Digita l Output P ort, on page 43

• To Read th e Tota lizer C ount, on page 44

• To Output a DC Volta ge, on page 45

• To Configure the Remote In terfa ce, on page 46

• To St ore the Inst rument S ta te, on page 48

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Chapter 2 Front-Panel OverviewFront-Panel Menu Reference

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Configure the advanced measurement features on displayed channel.

• Set the integration time for measurements on the displayed channel.• Set the channel-to-channel delay for scanning.• Enable/disable the thermocouple check feature (T/C measurements only).• Select the reference junction source (T/C measurements only).• Set the low frequency limit (ac measurements only).• Enable/disable offset compensation (resistance measurements only).• Select the binary or decimal mode for digital operations (digital input/output only).• Configure the totalizer reset mode (totalizer only).• Select which edge is detected (rising or falling) for totalizer operations.

Configure system-related instrument parameters.

• Set the real-time system clock and calendar.• Query the firmware revisions for the mainframe and installed modules.• Select the instrument’s power-on configuration (last or factory reset).• Enable/disable the internal DMM.•

Secure/unsecure the instrument for calibration.

View readings, alarms, and errors.

• View the last 100 scanned readings from memory (last, min, max, and average).• View the first 20 alarms in the alarm queue (reading and time alarm occurred).• View up to 10 errors in the error queue.• Read the number of cycles for the displayed relay (relay maintenance feature).

Store and recall instrument states.

• Store up to five instrument states in non-volatile memory.• Assign a name to each storage location.• Recall stored states, power-down state, factory reset state, or preset state.

Configure the remote interface.

• Select the GPIB address.• Configure the RS-232 interface (baud rate, parity, and flow control).

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Chapter 2 Front-Panel OverviewTo Monitor a Single Channel

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To Monit or a S ingle Ch a nn elYou can use the Monitor function t o continuously t a ke readings on a singlechannel, even during a scan. This feature is useful for troubleshooting yoursystem before a test or for w a tching a n importa nt signal.

1 Select the channel to be monitored.

Only one channel ca n be monitored at a t ime but you ca n cha nge the

chann el being monitored a t a ny t ime by turning th e knob.

2 Enable monitoring on the selected channel.

Any chan nel tha t ca n be “rea d” by the instrument ca n be monitored(the MON a nnun cia tor tur ns on). This includes a ny combina tion oftem perat ure, volta ge, resista nce, current, frequency, or periodmeasurement s on multiplexer channels. You can a lso monitor a digita l

input port or the tota lizer count on the mult ifunction module.

To di sable moni tori ng, pr ess again .

2

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Chapter 2 Front-Panel OverviewTo Set a Scan Interval

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To Set a Scan Int erva l

You ca n set the instrument’s interna l t imer to a utoma tically sca n a t aspecific int erval (e.g., sta rt a new scan sw eep every 10 seconds) or wh enan external TTL t rigger pulse is received. You ca n configure theinstrum ent t o sca n continuously or to stop a fter sweeping t hrough thescan list a specified number of times.

1 Select the interval scan mode.

For th is exam ple, select th e I nt er val Scan mode wh ich a llow s you to setthe time from the sta rt of one sca n sw eep to the sta rt of the next sca nsweep. Set t he interval to an y va lue betw een 0 an d 99 hours.

2 Select the scan count.

You can specify the num ber of t imes tha t t he instrument w ill sweepth rough t he scan list (th e default is cont inuous). When t he specifiednum ber of sweeps ha ve occurred, th e sca n st ops. Set t he scan count t oa ny n umber betw een 1 an d 50,000 sca ns (or cont inuous).

3 Run the scan and store the readings in memory.

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Chapter 2 Front-Panel OverviewTo Configure Alarm Limits

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To Configure Alarm Limits

The instrument ha s four a larm s w hich you can configure to alert youw hen a r ead ing exceeds specified limits on a chan nel during a sca n.You can a ssign a high l imit , a low l imit , or both to a ny configuredchannel in th e sca n l ist . You can a ssign multiple cha nnels to a ny of thefour a va ilable ala rms (numbered 1 th rough 4).

1 Configure the channel.

You m ust configure t he cha nnel (function, tr a nsducer t ype, etc.) beforesetting a ny a larm limits. I f you cha nge the measurement configuration,a larm s ar e turned off and t he l imit va lues a re clear ed. I f you pla n t o useMx+ B sca ling on a cha nnel which w ill also use alarm s, be sur e to confi gur e the scal in g val ues fir st .

2 Select which of the four alarms you want to use.

3 Select the alarm mode on the selected channel.

You ca n configure the instrument to genera te an a larm w hen amea surement exceeds the specified HI or LO limits (or both) on ameasurement cha nnel.

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Chapter 2 Front-Panel OverviewTo Read a Digital Input Port

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To Read a D igita l Input P ort

The m ultifu nction module (34907A) ha s t w o non-isolat ed 8-bitinput/output ports w hich you ca n use for rea ding digita l pa tt erns.You can r ead t he live sta tus of the bits on the port or you can configurea sca n t o include a digita l read.

1 Select the Digital Input port.

Select t he slot cont a ining th e multifunction module and cont inueturning the knob unti l DIN is displa yed (cha nn el 01 or 02).

2 Read the specified port.

You can specify wh ether you wa nt to use bina ry or decimal forma t.Once you ha ve selected t he num ber bas e, it is used for a ll input oroutput opera tions on the sa me port. To chan ge the num ber base,

press th e key a nd select USE BINARY or USE DECIMAL.

The bit pat tern r ead from t he port w ill be display ed until you press

a nother key, turn t he knob, or unti l the displa y t imes out.

No t e : To add a di gital in put channel t o a scan l ist, press and select the DIO READ choi ce.

Bi nary Di splay Shown

Bit 7 Bit 0

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Chapter 2 Front-Panel OverviewTo Write to a Digital Output Port

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To Writ e to a D igita l Output P ort

The m ult ifunction module (34907A) ha s t w o non-isolat ed 8-bitinput/output ports w hich you can u se for outputt ing digita l pat tern s.

1 Select the Digital Output port.

Select t he slot cont a ining th e multifunction module and continueturn ing the knob unti l DIN is displa yed (cha nn el 01 or 02).

2 Enter the bit pattern editor.

Notice tha t t he port is now converted to an output port (DOUT).

3 Edit the bit pattern.

U se the knob a nd or keys to edit the individual bit values.You can specify wh ether you wa nt to use bina ry or decima l forma t.Once you ha ve selected t he num ber base, it is used for all input oroutput opera tions on the sa me port. To chan ge the num ber base,

press th e key a nd select USE BINARY or USE DECIMAL.

4 Output the bit pattern to the specified port.

The specified bit pattern is latched on the specified port. To cancel anoutput opera tion in progress, wa it for the display t o time out.

Bi nary Di splay Shown

Bit 7 Bit 0

Decim al Di splay Shown

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Chapter 2 Front-Panel OverviewTo Output a DC Voltage

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To Output a DC Volta ge

The m ultifunction module (34907A) has tw o an a log output s ca pable ofoutputt ing calibrated voltages betw een ±12 volts .

1 Select a DAC Output channel.

Select t he slot cont a ining th e multifunction module and continueturn ing the knob unti l DAC is displa yed (cha nn el 04 or 05).

2 Enter the output voltage editor.

3 Set the desired output voltage.

U se th e knob a nd or keys to edit th e individual digits.

4 Output the voltage from the selected DAC.

The output volta ge will be displayed un til you press a nother key or turn

th e knob. To ma nua lly reset th e output volta ge to 0 volts, press .

2

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Chapter 2 Front-Panel OverviewTo Configure the Remote Interface

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To Configure t he Remote In t erfa ce

The instrument is shipped wit h both a n G P I B (IEEE -488) interfaceand an RS-232 int erfa ce. Only one interfa ce can be ena bled at a time.The G P I B interfa ce is selected w hen th e instrum ent is shipped fromthe fa ctory.

GPIB Configuration

1 Select theGPIB (HPIB) interface.

2 Select theGPIB address.

You can set t he instrument’s address to an y va lue between 0 and 30.The fa ctory settin g is a ddress “9”.

3 Save the change and exit the menu.

No t e : Your comput er ’s GPI B i nt er face car d h as its own ad dr ess.

Be sur e to avoi d u si ng t he compu ter ’s add r ess for an y in str um ent on the i nt er face bus. Agi l ent ’s GPI B i nt er face car ds general l y use addr ess “21”.

Interface

Interface

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RS-232 Configuration

1 Select the RS-232 interface.

2 Select the baud rate.

S elect one of t he follow ing : 1200, 2400, 4800, 9600, 19200, 38400,57600 (factor y sett in g ), or 115200 baud.

3 Select the parity and number of data bits.

Select one of the follow ing: None (8 dat a bits, factor y sett i ng ),Even (7 da ta bits), or Odd (7 dat a bits). When you set th e pa rity ,you are a lso indirectly setting the num ber of da ta bits.

,

4 Select the flow control method.

S elect one of th e follow ing: None (no flow cont rol), RTS /CTS , D TR/DS R ,XON /XOF F (factor y sett i ng ), or Modem.

5 Save the changes and exit the menu.

Interface

Interface

Interface

Interface

2

47

Chapter 2 Front-Panel OverviewTo Store the Instrument State

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To St ore the Instrum ent St a te

You can st ore th e instrum ent st a te in one of five non-vola tile storag elocat ions. A sixth st orage loca tion a utoma tically holds the pow er-downconfigura tion of th e instrument . When power is restored, th e instrum entcan a utomat ica lly return to i ts sta te before pow er-dow n (a scan inprogress before power-down will also be resumed).

1 Select the storage location.

From th e front panel, you ha ve the a bili ty t o assign na mes (up to 12char a cters) to each of th e five stored sta tes.

The st orage locat ions a re nu mbered 1 th rough 5. The power-downsta te is aut omat ica lly stored an d can be reca lled from t he front panel(the sta te is named LAST PWR DOWN).

2 Store the instrument state.

The instrum ent st ores a l l cha nnel configurations, a larm values, sca lingvalues, sca n interva l setups, an d a dvan ced measurement configurations.

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S yst em Overview

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S yst em Overview

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This cha pter provides a n overview of a computer-ba sed syst em a nddescribes the part s of a d a ta a cquisition syst em. This chapt er is dividedinto t he following sections:

• Da ta Acquisit ion S ystem Overview, see bel ow

• Signal Routing and Switching, star ti ng on page 57

• Measurement Input, star ti ng on page 60

•Control Output, star ti ng on page 67

D a ta Acquisition S yst em Overview

You can use the Agilent 34970A a s a sta nd-a lone instr ument but t here a re

ma ny a pplica tions w here you w ill wa nt to ta ke advan ta ge of the built-in P Cconnectivity fea tures. A typical da ta a cquisition system is shown below .

Computerand Software Interface Cable 34970A

Plug-inModules

SystemCabling

Transducers,Sensors,

and Events

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Chapter 3 System OverviewData Acquisition System Overview

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The syst em configura tion show n on th e previous pa ge offers thefollowing a dvan ta ges:

• You ca n use th e 34970A to perform da ta stora ge, dat a reduction,ma thema tica l calculat ions, a nd conversion to engineering units.You can use the P C to provide ea sy configura tion and da ta present a tion.

• You can remove the a na log signals a nd mea surement sensors fromthe noisy P C environment a nd electrically isolat e them from both t heP C a nd ear th ground.

•

You ca n use a single P C to monitor multiple instrum ents a ndmeasurement points while performing other P C -based tasks.

The Computer and Interface Cable

Sin ce comput ers an d opera ting syst ems a re the subject of ma ny booksa nd periodica ls, they a re not discussed in t his cha pter. In a ddition t o thecomputer a nd opera ting sy stem, you will need a s erial port (RS -232) orG P I B port (I E E E-488) a nd a n interfa ce ca ble.

Serial (RS-232) GPIB (IEEE-488)

Advantages Disadvantages Advantages Disadvantages

Often built into the computer;no additional hardware isrequired.

Cable length is limitedto 45 ft (15 m). *

Speed; faster data andcommand transfers.

Cable length is limitedto 60 ft (20 m). *

Drivers usually included inthe operating system. Only one instrument ordevice can be connectedper serial port.

Additional system flexibility,multiple instruments canbe connected to thesame GPIB port.

Requires an expansionslot plug-in card in PCand associated drivers.

Cables readily availableand inexpensive.

The 34970A isshipped with a serial cable(if internal DMM is ordered).

Cabling is susceptible tonoise, causing slow orlost communications.

Varying connector pinoutsand styles.

Direct Memory Transfersare possible.

Requires special cable.

Data transfers up to85,000 characters/sec.

Data transfers up to750,000 characters/sec.

* You can over come these cable length l im it ati ons usin g special comm un icati ons har dwar e.For exampl e, you can use the Agil ent E5810A L AN -to-GPI B Gat eway i nterface or a seri al modem .

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M S f


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Measurement Software

A va riety of softw a re is a vailable to configure your da ta a cquisit ionha rdwa re and ma nipulate and display your measurement data .

Da t a L og gi n g a n d Mon i t o r i n g

Agil ent B enchLi nk Dat a L ogger is a Windows ® -based applicationdesigned to ma ke it easy to use th e 34970A w ith y our P C for ga theringa nd a na lyzing m easurements. The softw a re is included w ith t he 34970A

w hen you order the interna l D MM . Use th is softw a re to set up your test ,a cquire an d a rchive mea surement da ta , an d perform rea l-time displaya nd a na lysis of your incoming mea surements.

Au t oma t ed Test i n g w i t h Mu l t i p l e I n st r um en t s

• Agilent VEE

• Tra nsE ra HTB ASIC ® for Window s

• Nat iona l Instruments La bVIEW

• Microsoft ® Visual B a sic or Visual C+ +

Agilent BenchLink Data Logger

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Th 34970A D t A i iti /S it h U it


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The 34970A Data Acquisition / Switch Unit

As sh own below, t he logic circuitry for t he 34970A is divided int o tw osections: earth-referenced and f loat ing . These tw o sections a re isola tedfrom each other in order to ma inta in measurement a ccura cy andrepea ta bili ty (for more informati on on gr ound loops, see page 341 ).

The ear th -referenced an d floa ting circuitry comm unicat e wit h ea chother via a n optically-isolat ed da ta link. The ea rt h-referenced sectioncomm unicat es wit h t he floa ting section to provide P C connectivity .The instrument is shipped w ith both a n G P I B (I E E E-488) interfacea nd a n RS -232 interfa ce. Only one interface ca n be ena bled a t a t ime.

The ear th -referenced section a lso provides four ha rdw a re ala rm output sa nd externa l tr igger l ines. You can u se the a larm output l ines to tr iggerexterna l ala rm lights, sirens, or send a TTL pulse to your cont rol system.

The floa ting section conta ins th e ma in syst em processor an d cont rols allof th e basic functiona lity of the inst rument . This is wh ere the instrum entcomm unicat es with the plug-in modules, scans t he keyboa rd, contr ols t hefront-panel display, and controls the internal D MM . The floa tin g sectiona lso performs Mx+ B sca ling, m onitors a larm conditions, convertstra nsducer measurements t o engineering units, t ime sta mps sca nnedmea surement s, a nd st ores dat a in non-volat i le memory.

To Computer

AC Power

Alarms

GPIB

RS-232

EarthReferenced Logic

Floating Logic

InternalDMM

DigitalBus

Analog Bus

Plug-In Slots

100

200

300

External Trigger

Control

Optional

= Optical Isolators

OUT

IN 3

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Plug In Modules


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Plug-In Modules

The 34970A offers a complete selection of plug-in modules to give youhigh-qua lity measurement, sw itching, a nd control capabil i t ies.The plug-in m odules comm unica te w ith th e floa ting logic via the interna lisolat ed digita l bus. The mult iplexer m odules a lso connect to t heinternal D MM via t he internal a na log bus. Ea ch module has i ts ownmicroprocessor t o offloa d th e ma infra me processor a nd m inimizeba ckpla ne communica tions for fas ter t hroughput. The ta ble below showssome comm on uses for ea ch plug-in module.

For mor e i nformati on on each m odu l e, refer to the modul e secti ons in

chapt er 4, star ti ng on page 163.

Model Number Module Name Common Uses

Measurement Input

34901A 20-Channel Mux with T/C

Compensation

Scanning and direct measurement of

temperature, voltage, resistance, frequency,and current (34901A only) using theinternal DMM.34902A 16-Channel Reed Mux with T/C

Compensation

34908A 40-Channel Single-Ended Muxwith T/C Compensation

Scanning and direct measurement oftemperature, voltage, and resistance usingthe internal DMM.

34907A Multifunction Module Digital Input, Event Counting.

Signal Routing

34901A 20-Channel Mux with T/CCompensation

Multiplexing of signals to or from externalinstruments.

34902A 16-Channel Reed Mux with T/CCompensation

34908A 40-Channel Single-Ended Muxwith T/C Compensation

34904A 4x8 Matrix Switch 32 Crosspoint Matrix switching.

34905A Dual 4-Channel RF Mux (50Ω) 50Ω high-frequency applications (< 2 GHz).

34906A Dual 4-Channel RF Mux (75Ω) 75Ω high-frequency applications (< 2 GHz).

Control Output

34903A 20-Channel Actuator General-purpose switching and controlusing Form C (SPDT) switches.

34907A Multifunction Module Digital Output, Voltage (DAC) Outputs.

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System Cabling


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System Cabling

The plug-in modules ha ve screw -term ina l connectors t o ma ke it ea sy t oconn ect y our syst em cabling. The ty pe of cabling th a t y ou use to connectyour signals, tra nsducers, an d sensors to the m odule is cri t ica l tomea surement success. Some types of tra nsducers, such a s t hermocouples,ha ve very specific requirement s for th e type of ca ble th a t ca n be used toma ke connections. B e sure to consider th e usa ge environment w henchoosing w ire gauge a nd insula tion qua lities. Wire insula tion typicallyconsists of ma terials such a s P VC or Teflon ® . The table below lists

several common ca ble types an d describes th eir typica l uses.

No t e : Wir in g insulati on and u sage is descri bed i n mor e detai l i n “System Cabl i ng an d Connecti ons” star ti ng on page 335.

Cable Type Common Uses Comments

ThermocoupleExtension Wire

Thermocouple measurements. Available in specific thermocouple types.Also available in a shielded cable foradded noise immunity.

Twisted Pair,Shielded Twisted Pair

Measurement inputs, voltageoutputs, switching, counting.

Most common cable for low-frequencymeasurement inputs. Twisted pairreduces common mode noise.Shielded-twisted pair provides additionalnoise immunity.

Shielded Coaxial,Double-Shielded

Coaxial

VHF signal switching. Most common cable for high-frequencysignal routing. Available in specific

impedance values (50Ω or 75Ω).Provides excellent noise immunity.Double-shielded cable improvesisolation between channels. Requiresspecial connectors.

Flat Ribbon,Twisted Pair Ribbon

Digital Input/Output Often used with mass terminationconnectors. These cables provide littlenoise immunity.

Teflon i s a r egister ed tr ademar k of E.I. duPont deN emour s and Company.

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Transducers and Sensors


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Transducers and Sensors

Tra nsducers a nd sensors convert a physica l qua nti ty into an electricalqua ntity . The electrical qua nt i ty is measured a nd t he result is th enconverted t o engineering units. For example, when m easu ring ath ermocouple, the instrument measures a dc voltage a nd ma thema ticallyconverts it to a corresponding t empera tu re in °C , °F, or K.

Measurement Typical Transducer Types Typical Transducer Output

Temperature Thermocouple 0 mV to 80 mVRTD 2-wire or 4-wire resistance

from 5Ω to 500Ω

Thermistor 2-wire resistance from10Ω to 1 MΩ

Pressure Solid State ±10 Vdc

Flow Rotary TypeThermal Type

4 mA to 20 mA

Strain Resistive Elements 4-wire resistance from10Ω to 10 kΩ

Events Limit SwitchesOptical CountersRotary Encoder

0V or 5V Pulse Train

Digital System Status TTL Levels

Alarm Limits

The 34970A ha s four a la rm output s w hich you ca n configure t o alert youw hen a r ead ing exceeds specified limits on a chan nel during a sca n.You can a ssign a high l imit , a low l imit , or both to a ny configuredchannel in th e sca n l ist . You can a ssign multiple cha nnels to a ny of thefour a va ilable ala rms (numbered 1 th rough 4). For example, you canconfigure the instrument to generat e an a larm on Alarm 1 w hen a l imitis exceeded on a ny of cha nn els 103, 205, or 320.

You can a lso a ssign a larms to channels on the multi function m odule.For exa mple, you can generat e an a larm w hen a specif ic bit pat tern orbit pa tt ern cha nge is detected on a digital input channel or w hen a specificcount is rea ched on a tota lizer cha nnel. With the m ultifunction m odule,the cha nnels do not ha ve to be pa rt of the sca n list to generate a n a larm.

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Si l R ti d S it hi

Chapter 3 System OverviewSignal Routing and Switching

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Signa l Routing an d Sw itching

The sw itching capa bilities of th e plug-in modules ava ilable wit h t he34970A provide test syst em flexibility a nd expa nda bility. You can useth e swit ching plug-in modules to route signa ls to an d from your testsyst em or multiplex signals to th e interna l DMM or externa l inst rument s.

Rela ys a re electr omecha nical devices wh ich a re subject t o wea r-outfa ilure modes. The life of a rela y, or th e number of a ctua l opera tionsbefore failure, is dependent upon h ow it is used – a pplied loa d, switchingfrequency, a nd environment . The 34970A Relay Maintenance System a utoma tically counts the cycles of ea ch relay in the inst rument a ndstores th e tota l count in non-volat ile memory on ea ch sw itch module.Use t his fea ture to tra ck rela y failures a nd to predict syst em ma intenancerequirements. For more inform ati on on using th is featur e, refer to “Rel ay Cycle Count ” on page 147.

Switching TopologiesSeveral switching plug-in modules are available with differenttopologies for various applications. The following switching topologiesare ava i lable:

• Mu lt iplexer (34901A, 34902A, 34905A, 34906A, 34908A)

• Matrix (34904A)

• Form C – Sin gle P ole, D ouble Thr ow (34903A)

The following sections describe each of these switching topologies.

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Mu l t i p l ex er Sw i t c h i n g Multiplexers allow you to connect one of


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mult iple cha nnels t o a common cha nnel, one at a time. A simple 4-to-1

mult iplexer is sh own below . When y ou combine a m ultiplexer w ith ameasurement device, like the internal DMM , you crea te a sca nner.For mor e i nformati on on scann i ng, see page 62.

Multiplexers are available in several types:

• One-Wir e (Sin gle-Ended) M ul ti pl exer s for comm on LO measurements.

For more informa tion, see page 379.• Tw o-Wir e M ul ti plexers for f loa ting m easurements. F or m ore

informa tion, see pa ge 379.

• Four-Wi r e M ul ti plexers for resistan ce an d RTD measurements.For more informa tion, see page 380.

• Ver y H igh F r equency (VHF) M ul ti plexer s for swit ching frequenciesup to 2.8 G Hz. F or more informa tion, see page 390.

Common

Channel 1

Channel 4

Channel 3

Channel 2

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Ma t r i x Sw i t c h i n g A ma trix swit ch connects multiple inputs to


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mult iple output s a nd t herefore offers more sw itching flexibility t ha n a

multiplexer. Use a ma trix for switching low-frequency (less tha n 10 MHz)signals only. A ma trix is ar ra nged in rows a nd columns. For exa mple,a simple 3x3 mat rix could be used to connect t hree sources t o three testpoints a s shown below .

Any one of th e signa l sources can be connected t o an y one of th e testinputs. Be aw a re tha t w ith a ma trix, it is possible to connect more tha none source at the sa me time. It is importa nt to ma ke sure tha t da ngerousor unw a nt ed conditions a re not crea ted by th ese connections.

Fo rm C (SPDT ) Sw i t c h i n g The 34903A Actua tor cont a ins 20 Form Csw itches (a lso ca lled single-pole, doubl e-th r ow ). You can use Form Cswit ches to route signals but th ey a re typica lly used t o control externa ldevices.

Source 2

Test 1 Test 2 Test 3

Source 3

Source 1

NC

COM

NO

NC

COM

Channel Open (NC Contact Connected)

Channel Closed (NO Contact Connected)

NO

NO = Normally OpenNC = Normally Closed

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Measurement Input

Chapter 3 System OverviewMeasurement Input

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Measurement Input

The 34970A a llow s y ou t o combin e a DMM (either interna l or externa l)w ith mult iplexer chann els to crea te a scan . During a scan, th e instrumentconnects the DMM to the configured mult iplexer chan nels one a t a timea nd ma kes a m easurement on ea ch chann el.

Any chan nel tha t can be “rea d” by the instrument ca n a lso be includedin a scan . This includes a ny combina tion of tem perat ure, volta ge,resista nce, current , frequency, or period mea surement s on multiplexerchannels. A scan can a lso include a read of a digita l port or a r ead of thetota lizer count on the m ultifunction module.

The Internal DMM

A tran sducer or sensor converts a physica l qua nti ty being mea suredinto an electrical signal w hich can be measured by the interna l DMM.To make th ese mea surements, the interna l DMM incorpora tes th e

follow ing functions:

• Temperature (thermocouple, RTD , and th ermistor)

• Volta ge (dc a nd a c up to 300V)

• Resist a nce (2-w ire a nd 4-w ire up t o 100 MΩ)

• Cur rent (dc an d a c up to 1A)

• Freq uency an d P eriod (up to 300 kHz)

The intern a l DMM provides a un iversal input front-end for mea suringa variety of tra nsducer types without th e need for a dditiona l externa lsigna l conditioning. The int erna l D MM includes signa l conditioning,a mplificat ion (or a tt enua tion), a nd a high resolution (up to 22 bits)a na log-to-digita l converter. A simplified diagra m of the int erna l D MM isshown below.

= Optical Isolators

AnalogInputSignal

SignalConditioning

Amp MainProcessor

To / FromEarthReferencedSection

Analog toDigital

Converter

60

S i g na l Cond i t i on i n g , Ran g i n g , a nd Amp l i f i c a t i on Ana log inputsignals a re multiplexed into th e interna l D MM ’s signal conditioning


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signals a re multiplexed into th e interna l D MM s signal-conditioning

section – t ypica lly comprising sw itching, ra nging, a nd a mplif ica tioncircuitry. If th e input sign a l is a dc volta ge, the signa l conditioneris composed of an a tt enuat or for t he higher input voltages a nd adc amplifier for th e low er input volta ges. If the input signa l is ana c volta ge, a convert er is used to convert th e ac signa l to its equ ivalentdc va lue (tr ue RMS value). Resista nce mea surement s a re performed bysupplying a known dc current t o an unknown resista nce a nd mea suringth e dc volta ge drop a cross th e resistor. The input signa l swit ching an d

ranging circuitry, together with the amplifier circuitry, convert theinput to a dc volta ge which is with in the measuring ra nge of theinternal D MM ’s analog-to-digital converter (ADC ).

You can a llow the instrument to aut oma tically select t he measurementra nge using autoranging or you can select a f ixed mea surement ra ngeusing manual r anging . Autora nging is convenient because th e instrum enta utomat ica lly decides w hich ra nge to use for each mea surement based

on the input signa l . For fast est sca nning operat ion, use man ual ra ngingfor ea ch measurement (some a dditiona l t ime is required for aut orangingsince the instrument ha s to ma ke a ra nge selection).

Ana l og -t o -D i g i t a l Conver si on (ADC) The ADC ta kes a presca leddc volta ge from th e signa l-conditioning circuitry a nd converts it t o digita lda ta for output a nd displa y on th e front panel. The ADC governs s ome ofth e most ba sic measurement chara cteristics. These include measurementresolution, r eading speed, a nd t he a bility to reject spurious noise. There

a re severa l an a log-to-digita l conversion techniqu es but th ey ca n bedivided int o tw o types: integrat ing and non-integrating . The integra tingtechniques mea sure the a verage input va lue over a defined timeint erval, t hus r ejectin g ma ny n oise sources. The non-integra tingtechniques sa mple the insta nta neous va lue of the input, plus noise,during a very short interval . The interna l D MM uses an integrat ingADC technique.

You can select th e resolution a nd r eading speed from 6 digits (22 bits) a t3 readings per second to 4 digits (16 bits) a t u p to 600 readings per second.The Advanced menu from th e 34970A front pa nel a llow s you t o controlth e int egra tion period for precise rejection of noise signa ls.

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You can configure th e event or action th a t controls the onset of ea chsweep through the scan list (a sweep is one pass t hrough t he scan list):


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sweep through the scan l ist (a sweep is one pass t hrough t he scan list):

• You ca n set th e instrum ent’s interna l t imer to a utoma tically sca n a ta specif ic interva l as shown below. You can a lso progra m a t ime delaybetween channels in the scan l ist .

• You ca n ma nua lly control a sca n by repeat edly pressing fromthe front panel.

• You ca n sta rt a sca n by sending a softw a re comman d from th eremote interface.

• You can s ta r t a scan wh en an external TTL tr igger pulse is received.

• You ca n sta rt a sca n w hen an a larm condition is logged on th echa nnel being monitored.

Scan List (1 sweep)

t

Scan-to-Scan Interval (0 to 99:59:59 hours)

Scan Count(1 to 50,000 scans, or continuous)

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Scanning With External Instruments


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If your a pplica tion doesn’t req uire the built-in mea surement capa bilitiesof th e 34970A, you ca n order it w ithout t he int erna l D MM . In thisconfigura tion, you ca n u se t he 34970A for signa l routing or cont rola pplica tions. If you insta ll a m ultiplexer plug-in module, you can use th e34970A for scan ning w ith a n externa l inst rumen t. You can connect a nexternal instrument (such a s a DMM) to th e mult iplexer COM terminal.

To contr ol scanning w ith a n externa l instrument, tw o control lines areprovided. When the 34970A and the external instrument are properlyconfigured, you ca n syn chronize a scan sequ ence betw een the tw o.

Common Terminals(COM)

H

InputChannels

L

H

L

External DMM H

L

H

L

VM Complete OUT Ext Trig IN

GND

Ext Trig INChannel Closed OUT

External DMM34970A

64

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To ta l i ze r The multifunction module ha s a 26-bit tota lizer w hich ca ncount pulses at a 100 kHz ra te. You can ma nua lly read the tota l izer


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count or you can configure a scan t o rea d th e count.

• You can configure th e tota lizer t o count on t he rising edge or fa llingedge of the input signa l.

• The m a ximum count is 67,108,863 (226- 1). The count rolls over to “0”

a fter rea ching th e maximum a llowed va lue.

• You can configure the tota lizer to read w ithout a ffecting t he count orreset th e count t o zero w ith out losing a ny count s.

+IN

Gate

-IN

Gate

Totalize26 Bits

Channel 03

66

Contr ol Output

Chapter 3 System OverviewControl Output

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In a ddition to signal routing and m easurement, you ca n a lso use the34970A to provide simple cont rol out puts . For exa mple, you can cont rolexterna l high-power r ela ys using t he a ctuat or module or a digita l outputchannel.

The Multifunction Module

The m ultifunction module (34907A) a dds t w o additiona l cont rol outputcapa bilities to the system: digital output and volt age (DAC) output .

Th e mu lt ifu nction modul e also contai ns digit al i nput and event totali zer

capabi li ti es whi ch a r e descr ibed in more detai l on pages 65 and 66.

D i g i t a l O u t p u t The mult ifunction module ha s tw o non-isolat ed 8-bitinput/output ports w hich you ca n use to output d igita l pat terns . Ea chport ha s a sepa ra te chan nel number on t he module a nd conta ins 8-bits.

You can combine t he tw o ports to output a 16-bit w ord.

Bit 0

DigitalOutput

Bit 7Bit 0

Bit 7

8

8

Port 1 (LSB)Channel 01

Port 2 (MSB)Channel 02

3

67

Vo l t age (DAC) Ou tp u t The multifunction module ha s two ana logoutputs capable of outputting calibrated voltages between ±12 volts w ith

b A


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16 bits of resolution. Each DAC (Di gital -to-Anal og Conver ter ) chan nel ca nbe used as a program ma ble volta ge source for ana log input cont rol ofother devices. A simplified diagra m is sh own below .

• You can set t he output volta ge to any va lue between + 12 Vdc and

-12 Vdc, in 1 mV steps. E a ch D AC is eart h referenced, i t cannot fl oat .• Each D AC chan nel is ca pable of supplying 10 mA ma ximum current .

No te : You must li mi t the outpu t cur rent to 40 mA total for all th r ee sl ots (si x DAC channels).

DAC 116

Channel 04

16DAC 2 Channel 05

68

The Actuator / General-Purpose Switch

Y th i k f th 34903A A t t t l t t b it i


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You can th ink of the 34903A Actua tor a s a cont rol output beca use it isoften used t o cont rol extern a l pow er devices. The a ctua tor provides20 independent, isola ted Form C (S P D T) switches.

Ea ch cha nnel ca n sw itch up to 300V dc or ac rms. Ea ch sw itch can a lsosw itch up to 1 A dc or a c rms up t o 50 W ma ximum. F or exa mple, thema ximum current th a t y ou ca n sw itch a t 120 V is 0.45 A a s shown below.

For control a pplications, the actua tor ha s th e following a dvan ta ges:

• Higher volta ge and pow er rating th a n the digita l output chann els.The a ctua tor sw itches can a lso be used to cont rol power devices.

• When used w ith h igh-pow er devices, however, it is critical t ha t youprovide protection to the sw itch from ca pacitive an d inductive loa dsto ensure ma ximum relay l i fe (for mor e in formati on on att enuat ors,see th e d i scussion on page 387 ).

NC

COM

NO

NC

COM

Channel Open (NC Contact Connected)

Channel Closed (NO Contact Connected)

NO

NO = Normally OpenNC = Normally Closed

Voltage

Current

3

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70

4

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Fea tures a ndFunctions

4

Fea tur es a nd Functions

You w ill f ind th a t t his cha pter ma kes it ea sy to look up all the deta ilsa bout a pa rticular fea tur e of the 34970A. Wheth er you ar e operat ing

the inst rument from t he front panel or over the remote interface th isb

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the inst rument from t he front panel or over the remote interface, th ischapt er w ill be useful. This cha pter is divided int o the following sections:

• SCP I Lan guage Convent ions, on page 73

• Scanning, star ti ng on page 74

• Single-Channel Monitoring, star ti ng on page 93

• Scanning With External Instruments, star ti ng on page 95

• G enera l Measurement Configura tion, star ti ng on page 98 • Tempera ture Measurement Configura tion, start in g on page 106

• Volta ge Measurement Configura tion, star ti ng on page 113

• Resista nce Mea surement C onfiguration, on page 115

• Current Mea surement C onfigurat ion, star ti ng on page 116

• Frequency Measurement Configura tion, star ti ng on page 118

• Mx+ B Scal ing, star ti ng on page 119

• Alarm Limits, star ti ng on page 122

• Digita l Input Opera tions, star ti ng on page 133

• Tota lizer Operat ions, star ti ng on page 135

• Digita l Output Opera tions, on page 138

• DAC Output Opera tions, on page 139

• System-Related Operations, star ti ng on page 140

• Remote Int erfa ce Configura tion, star ti ng on page 150

• Ca librat ion Overview, star ti ng on page 155

• Fa ctory Reset St a te , on page 160

• Instrument Pr eset Sta te , on page 161

• Multiplexer Module Default Settings, on page 162

• Module Overview , on page 163

• 34901A 20-Ch a nn el Mult iplexer, star ti ng on page 164

• 34902A 16-Ch a nn el Mult iplexer, star ti ng on page 166 • 34903A 20-Ch a nn el Actua tor, star ti ng on page 168

• 34904A 4x8 Ma tr ix S w itch, star ti ng on page 170

• 34905A/6A D ua l 4-Ch a nn el RF Mult iplexers , star ti ng on page 172

• 34907A Mult ifunct ion Module, star ti ng on page 174

• 34908A 40-Ch a nn el Sin gle-E nded Multiplexer, star ti ng on page 176

72

SC P I La ngua ge Conventions

Throughout t his ma nua l the follow ing convent ions a re used for

Chapter 4 Features and FunctionsSCPI Language Conventions

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Throughout t his ma nua l, the follow ing convent ions a re used forS C P I comma nd synt a x for remote interface programming:

• Sq uar e brackets ( [ ] ) indicat e optional keyw ords or par a meters.

• B ra ces ( {}) enclose par a meter choices wit hin a comm a nd st ring.

• Triangle brackets ( < >) enclose par a meters for w hich you mustsubsti tute a va lue.

• A vert ica l ba r ( | ) separa tes mult iple pa ra meter choices.

Rules for Using a Channel List

Ma ny of the S C P I comm a nds for t he 34970A include a scan_list or ch_list para met er wh ich a llow you to specify one or more chan nels.The cha nnel n umber ha s the form (@scc ), where s is the slot number(100, 200, or 300) a nd cc is th e cha nnel number. You ca n specify a singlechan nel, multiple chan nels, or a ra nge of cha nnels as sh own below .

• The follow ing comm a nd configures a scan list t o include onlychannel 10 on the module in slot 300.

ROUT:SCAN (@310)

• The follow ing comm a nd configures a scan list t o include multiplecha nnels on t he module in slot 200. The scan list now cont a ins onlycha nnels 10, 12, an d 15 (th e scan l i st i s redefin ed each t ime you send a new ROUTe:SCAN comman d ).

ROUT:SCAN (@210,212,215)

• The follow ing comm a nd configures a scan list to include a ra nge of

cha nnels. When you specify a ra nge of chan nels, the ra nge may conta in invalid cha nnels (they a re ignored), but th e f irst a nd la stchann el in t he ra nge must be valid. The sca n l ist now conta inscha nn els 5 thr ough 10 (slot 100) a nd cha nn el 15 (slot 200).

ROUT:SCAN (@105:110,215)

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• Ea ch time you sta rt a n ew sca n, the instrum ent clea rs al l rea dings(including a lar m da ta ) stored in reading m emory from th e previous

scan . Therefore, the cont ents of memory a re alw a ys from th e mostrecent scan

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recent scan.

• While a sca n is running, the instrument a utomat ica lly stores theminimum a nd ma ximum rea dings and calculat es the average for eachchann el. You ca n read t hese va lues at a ny t ime, even during a sca n.

• Mx+ B scaling an d ala rm limits a re applied to measurements during ascan a nd a ll dat a is stored in non-volat i le memory. You ca n rea d th econtents of reading memory or th e ala rm q ueue a t a ny t ime, evenduring a sca n.

• In t he Monitor function, the instrum ent t akes readings a s often a s i tcan on a single cha nnel, even during a scan (see “Si ngle-Channel M onit ori ng” on page 93 ). This feature is useful for troubleshootingyour system before a t est or for w a tching an importa nt signal .

• I f you abort a sca n th a t is running, the instrument w ill complete theone measu rement in progress (the entire scan w ill not be completed)

a nd t he sca n w ill stop. You cannot resume th e sca n from w here itleft off. If you initiat e a n ew sca n, a ll rea dings a re cleared from memory.

• When you add a multiplexer chan nel to a sca n l ist , tha t ent ire moduleis dedicat ed to the sca n. The instru ment issues a Ca rd Reset to opena ll cha nnels on t ha t module. You ca nnot perform low -level close oropen operat ions on a ny cha nn els on th a t m odule (even those cha nn elsthat are not configured).

• While a scan is run ning, you can perform some low -level cont roloperat ions on modules tha t do not cont a in channels in th e sca n l ist .For exam ple, you ca n open or close cha nnels or issue a C a rd Reseton switching modules th a t do not contain cha nnels in th e sca n l ist .However, you ca nnot cha nge any par a meters tha t a f fect th e sca n(channel configuration, scan interval , scaling va lues, a larm limits,Ca rd Reset, etc.) wh ile a sca n is runn

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