Keithley 619 Service manual

Instruction Manual

Model 619

Electrometer/Multimeter

01981, Keithley Instruments, Inc.

Cleveland, Ohio, U.S.A.

SPECIFICATIONS

VOLTS TEMPERATURE

MAXIMUM t YR.. 23’ *ST &WC a 2860°C

RANGE

2Oh” 199.999XlO~ 0.01 %f25 0.00*%+30

2: z

200 v 199.999 0.02% + 10 0.002%+ 0.3

INPUT CAPACITANCE: Less than or equal to 2OpF. INPUT CAPACITANCE: Less than or equal to 2OpF. INPUT RESISTANCE: Greater than or equal to 2OTi,. INPUT RESISTANCE: Greater than or equal to 2OTi,. NMRR: Greater than 55dS (greater than SWS with FILTER). NMRR: Greater than 55dS (greater than SWS with FILTER). CMRR: Greater than 1OOdS (greater than l25dS with FILTER). CMRR: Greater than 1OOdS (greater than l25dS with FILTER). ANALOG SETTLING TIME ItoO.l% of final value, unfiltered): Lessthan ANALOG SETTLING TIME ItoO.l% of final value, unfiltered): Lessthan

5ms. 5ms.

REAOINQ * I%rdg + OO”“ts, * wrdg + EO”“b,,~C

1.99999 0.01 x7+,0 0.002%+ 3 19,999s 0.02% + 10 o.oo*%+ 0.3

AMPS AMPS

f.lAxlM”M 1 VR.. 23-*vc f.lAxlM”M 1 VR.. 23-*vc 019% * 2.a.wc 019% * 2.a.wc ANALOG ANALOG

RANOE READINO *,%rdg+co”“ts, *,%rdg+oO”“ts,,~C RANOE READINO *,%rdg+co”“ts, *,%rdg+oO”“ts,,~C

2 “A 1.99999x 10Q 2 “A 1.99999x 10Q 0.35% +a 0.35% +a

20 nA 19.9999x

200 nPi 100.999 x lcr9 200 nPi 100.999 x lcr9 0.15% +26 0.15% +26 O.O1%C30 O.O1%C30

2 &A 1.99999x10-~ 2 &A 1.99999x10-~

20 +A 19.9999 x 106 20 +A 19.9999 x 106

200 PA 199.999 x 108 200 “A 199.999 x 108

2nlA 1.99999x lo-3

20rnA 19.9999 x 10~3 0.15% + to cm,%+ 3

INPUT VOLTAGE DROP: Less than ImV st full-scale except less than 0.6” ANALOG SETTLING TIME Ito 0.1% of final value, unfllteredl: 2nA NMRR: 2nA through 2+&n: 70dS; ZO,,A through ZA: 5EdS.

1.99999 0.15%125 0.01%+20

on 2A range. through 2pA: 50ms; 20+A through 2A: 5ms.

OHMS TEMPERATwtE

MAXlMUM

RANOE READlNG

2 k0 1.99999x103

20 k0 19.9999x103

200 k” 199.999x101

aA* 1.99999 x 106

*ml* 19.9999x106

200M” 199.999x105

2 GO 1.99999x 109

20 0” 19.9999x109

200 GO 199.999x109

2 m 1.99999 x 10’2

OHMS CURRENT SOURCES: 2k0. 20kk ,OO&

ANALOG OUTPUT: Analog output voltage level is ths product of ths Ohms

current source and the resistance being measured.

ANALOG SE’ITLING TIMES:

To 0.1% of final value, unfiltered, with less than lOOpF input cspacitsnce: 20Mn: 20ms.

To 10% of final value, unfiltered, using 6191 Guarded Input Adapter with less than IpF unguarded input ZOOGD: 15s cap.acitance:

ACCURACY ACCURACY COEFFICIENT COEFFICIENT FULL SCALE FULL SCALE

lo-9

ACCVRAC”

1 YR.. 23~*5%

* I%dc! + Cc.““uL,

ACCVRACV COEFFIUENT

TEMPERATURE TEMPERATURE

lN”ERTlNO lN”ERTlNO

0”TP”T 0”TP”T

0.02% + 30 0.02% + 30 0.2v 0.2v

0.35% +35 0.35% +35

0.15?6+,0 0.15?6+,0 o.ol%+ 3 o.ol%+ 3 2.0” 2.0”

0.15%+25 0.15%+25 ml%+30 ml%+30 0.2” 0.2”

0.15% + 10 0.15% + 10 o.ot%+ 3 o.ot%+ 3 2.0” 2.0”

0.1536+25 0.0,%+30

0.2 % +25

0.2 sb+,o o.w%+25

0.15%+10

0.35% + 25

0.35% + 10

0.36% + 10 I %flO

4 %flO

10 %+I0

zookn, ztvl*: rpA, ZOMO, 2GO: IOnA. 20GO through 2To: lOOpA.

o.w?&+ 3 o.w?&+ 3 2.w 2.w

2k0 through 2Mn: 5ms. ZOOMII 200ms.

2Gn: 150ms. ZOGO: 1.5s.

2Tn: 150s.

0.2v 0.2v

0.2”

2.w

None

IEEE-488 BUS IMPLEMENTATION

IRequlres installado” of Model 5193,:

Mu,t,,,ne Commands: DCL, LLO, SDC, GET. Uniline Commands: IFC. REN. EOI. SRCl. ATN. Compatible with

IEEE-488-1978 standard.

PROGRAMMABLE PARAMETERS:

Front Panel Controls: Function, Range, Filter, Zero Check, Zero Correct.,

Baseline Stare, Baseline Suppress.

Internal Parameters: SKI Response. Trigger Modes, Binary or ASCII

Data Formsts. number of readings to be stored. dats terminators, reading rates, integration period.

ADDRESS MODES: TALK DNLV and ADDRESSABLE. READING RATES

GENERAL

DISPLAY: Numeric: 0.56” LED digits, 4%.digit mantissa @ 6.2rdgis

(5%.digits @ 2.4 rdg/s in high resolution mode), 2 digit wponent, decimal point, signed exponent and mantissa.

OVERRANGE INDICATION: Display reads OFLO.

MAXIMVM ALLOWABLE INPUT: 250” rms DC to SOHz sinswave. INPUT CURRENT ,18=‘-28°C,: Less than 0.4pA. EXTERNAL TRIGGER: TTL compatible EXTWNAL TRIGGER and ELEC-

TROMETER COMPLETE.

INPUT CONNECTORS 16194 Electrometer rear panel,: 2A range: 5-w”

binding posts. All other functions and ranges via Teflon” insulated ttisxial connector.

OUTPUT CONNECTORS: Analog: Amphenol Series SO (MicrophoneI.

6194 Electrometer rear panel. IEEE: Amphenol or Cinch Series 57. 6193

IEEE Interface rear panel. SNC lchassis isolated) connecfions for EXTERNAL TRIGGER and ELECTROMETER COMPLETE,

MAXIMUM ALLOWABLE COMMON MODE VOLTAGES:

Input LO IChannel A) to line ground: 250” rms, DC to 60Hz sinewsve. Input LO IChannel SI to line ground: 250” rms, DC to 60Hr sinewave. Input LO IChannel A, to Input LO IChannel 61: 250” m,s, DC to SOHz

sinewave.

WARMUP: 1 hour to rated sccuracy.

POWER: 90-110, 105-125, 180-220 ar210-250”. 50 or 60Hz ,intemal switch

selected). 75W max., 100WA max. (intsmsllv fan cooled).

ENVIRONMENTAL LIMITS: Operstlng: On-50°C, up to 35OC at 70% non

condsnsina R.H. Storage: -2OOC to 70°C.

DIMENSIOk, WEIGH6 432mm wide x 127mm high x 406mm deep

(17” x 5” x V.7’~. stackable enclosure. Net weight, S.Skg 122 Ibs.1 with Chsnnel S Electrometer module and IEEE-488 lntsfface module.

ACCESSORIES SUPPLIED: One Model 6194 Electrometer Module and one

Model 6011 input Cable.

ACCESSORIES AVAILASLE:

Model 1OlgA: 5%” Universal Fixed Rack Mounting Kit Model 10195: Universal Slide Rack Mounting Kit Model 6011: Trisxisl Input Cable. lm (3 ft.) Model 6191: Guarded input Adapter Model 6193: IEEE-488 Interface Model 6194: Electrometer Module Model 6195: Maintenance Kit Model 7008-3: IEEE-488 Cable 13 ft., Made, 7009.6: IEEE-488 Cable 16 ft.,

TABLE OF CONTENTS

Paragraph

1.1

1.2

1.3

1.4

1.5

1.6

1.7

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

2.9.1

2.9.2

2.9.3

2.9.4

2.9.5

2.9.6

2.9.7 2 9.8 2 9.9

2.9.10

7.10 :2.10.1

2.10.2

2.10.3

2.11

2.12

2.13

2.14

2.14.1

2.14.2

2.15

2.16

2.17

2.18

2.19

2.20

2.21

2.22

2.23

2.24

2.25

2.26

2.27

2.28

2.29

2.30

Title

SECTION 1. GENERAL INFORMATION

Introduction .............................................................

Features ................................................................

Warrantylnformation .....................................................

ManualAddenda .........................................................

Safety Symbols and Terms ................................................

Unpackingandfnspection .................................................

Specifications ............................................................

SECTION 2. OPERATION

Introduction ..................................................

PreparationforUse ............................................

Pre-power Up Programming ....................................

Powerup..~ ..................................................

BeeperSelection ..............................................

TAlk Only Mode/Addressable Mode Selection

.....................

Reading Rate Selection ........................................

Operating Instructions .........................................

FrontPanelFunctions ..........................................

Annunciator and Display Group ...............................

Function Selector Group .....................................

DualChannel ...............................................

Volts, Amps and Ohms. ......................................

Range Selection ............................................

zero Controls ...............................................

Baseline Controls. ...........................................

......................................................

Filter

Resolution .................................................

Current Ranges, Common Input ...............................

ExternalFeedbackUse.. .......................................

ExternalTrigger .............................................

Charge ....................................................

Logarithmic Currents ........................................

Non-Decade Current Gains .....................................

System Operation (Using the Model 6193 IEEE-488 Interface)

Address Selection ..............................................

Bus Management Lines ........................................

Bus Commands Implemented .................................

Input Channel Control (Secondary Address is a or bl

..............

DataFormat ..................................................

ASCllFormat .................................................

Binan/Format ................................................

Programmable Terminator, .....................................

BufferReadings ...............................................

MeasurementTime ............................................

ReadingRateModes ...........................................

........................................................

Filter

ZeroCheck ...................................................

zerocorrect ..................................................

Baseline Store ................................................

Baseline Suppression ..........................................

Default Conditions ............................................

Talk-OnlyMode

...............................................

SRQ Status Byte Format .......................................

MachineStatus.. .............................................

........

..........

.........

.....

..........

....................

.................... 2-l

....................

.................... 2-1

....................

.................... 2-1

.................... 2-3

....................

.................... 2-4

.................... 2-5

....................

.................... 2-6

....................

.................... 2-8

.................... 2-6

.................... 2-9

.................... 2-10

.................... Z-10

.................... 2-10

.................... 2-11

....................

Page

1-l l-l l-l 1-l l-l l-l 1-l

2-l 2-1

2-3 2-3 2-3 2-3

2-5 2-6

2-7 2-7 2-7

2-14 2-14 2-15 2-16 2-16

2-16 2-16 2-16 2-16 2-16 2-18 2-18 2-18

TABLE OF CONTENTS (CONT.)

Paragraph

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

4.1

4.1.1

4.1.2

4.2

4.2.1

4.2.2

4.2.3

4.2.4

5.1

5.2

5.3

5.3.1

5.4

5.4.1

5.5

5.5.1

5.6

5.6.1

5.7

5.7.1

5.8

5.8.1

5.9

Title

SECTION 3. ACCESSORIES

Introduction Model 6191 Guarded Input Adapter

Model 6193 IEEE Standard 488 Output ..............

Model 6194 Electrometer Module ..................

Model 6195 Calibration Cover Model 6199 Rack Mounting Kit with Chassis Slides

Model 7008 IEEE-488 Digital Cable. ................

Model 6011 Triax Input Cable .....................

SECTION 4. PERFORMANCE VERIFICATION

Introduction ....................................

Required Test Equipment. ......................

Environmental Conditions ......................

Model 619 PerformanceVerification

Initial Conditions ..............................

Voltage Verification. ...........................

Current Verification, ...........................

Resistance Verification .........................

SECTION 5. THEORY OF OPERATION

Introduction ...................................................................................

PowerSuply ...................................................................................

Model 6194 Electrometer Module .................................................................

Theory of Operation for the Model 6194 Electrometer Module

Model 6193 IEEE-488 Interface Board

IEEE Interface Board Theory of Operation

CPUBoard ....................................................................................

CPUTheoryofOperation ......................................................................

IsolatorBoard .................................................................................

lsolatorBoardTheon/ofOperation

Display/Keyboard .............................................................................

Display/Keyboard Theory of Operation

A/DBoard ...................................................................................

A/DTheon/ofOperation .....................................................................

Filter/MultiplexerBoard ........................................................................

....................................

................

.....................

................

..............................................................

........................................................

.............................................................

.........................................................

..............

.............. .................. ............

.............. ...................

.............. .................. ............

... ..............

.............. .................. ............

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.............. ...... .......

..............

.......................................

.................. ............

............

.................. ............

...... .......

......

.......

Page

3-l 3-l 3-l 3-2 3-2 3-3 3-3 3-3

4-1 4-l

4-l 4-1 4-l

4-l 4-l 4-2

5-I

5-1

5-2

5-5

5-7 5-7 5-9

5-11 5-12 5-12 5-13 5-13 5-14

6.1

6.2

6.2.1

6.3

6.4

6.5

6.6

6.6.1

6.7

6.7.1

6.8

6.9

6.10

6.11

6.12

6.13

6.14

SECTION 6. MAINTENANCE

Introduction ...................................................................................

Pre-PowerUpProgramming .....................................................................

LineVoltageandFrequencySelection

BeeperSelection ...............................................................................

ReadingRateSelection .........................................................................

Calibrationlntroduction .........................................................................

Calibration/Test Equipment and Conditions

Recommended Test Equipment and Related lnfromation

InformationandAssumptions ....................................................................

Standards

Volts .........................................................................................

Amps

Ohms ........................................................................................

EnvironmentalCondltlons .........................................................................

Calibration ....................................................................................

Calibration Cover Installation .....................................................................

Calibration Adjustments .........................................................................

...................................................................................

........................................................................................

...........................................................

........................................................

...........................................

6-l 6-l 6-l 6-l 6-2 6-2 6-3 6-3 6-3 6-3 6-3 6-4

6-5 6-5 6-5 6-5 6-5

TABLE OF CONTENTS (CONT.)

Paragraph

6.15

6.16

6.17

6.18

6.18.1

6.18.2

6.19

7.1

7.2

7.3

7.4 7-5

Title

CalibrationFixture

Construction Information ........................................................................ 6-9

Calibration of 1.9GO Source ...................................................................... 6-9

Troubleshooting ............................................................................... 6-9

Special Handling of Static Sensitive Devices.,

TroubleshootingProcedure ................................................................... 6-10

FanFilterCleaning ............................................................................. 6-10

SECTION 7. REPLACEABLE PARTS

Introduction ................................................................................... 7-l

PartsList ...................................................................................... 7-l

Ordering Information ........................................................................... 7-l

FactoryService.. .............................................................................. 7-l

Schematic Diagrams and Component Location Drawings.

..............................................................................

....................................................

............................................

Page

6-8

6-9

7-l

iii

LIST OF ILLUSTRATIONS

Figure

2-l 2-2 Model 619 Front Panel Functions 2-3 2-4 Model 6194 Electrometer Input Circuitry 2-5 2-6 2-7

2-8 TimingDiagram ................................................................................ 2-12

2-9 2-10 2-11

z-12 3-l 3-2 3-3 3-4 3-5 3-6 4-l 4-2 4-3

5-l 5-2 5-3 5-4 5-5 6-l 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 6-10 6-11 7-l 7-2 7-3 7-4 7-5 7-6 7-7 7-8 7-8

Model619RearPanel ............................................................................. 2-2

...................................................................

Common Input Current Range

ChargeMeasurement ............................................................................. 2-9

Logarithmic Current Measurement. ................................................................. 2-9

Non-Decade Current Gain Measurement. ........................................................... 2-10

Start of Signal Integrate From Trigger (t1) (Trigger is a Negative Going Pulse)

BinaryFormat .................................................................................. Z-15

StatusByte .................................................................................... 2.19

MachineStatus ................................................................................. 2-19

Model619lGuardedAdapter Model 6193 IEEE Standard 488 Output Model 6194 Electrometer Module. Model6195MaintenanceKit Model 6199 Rack Mounting Kit with Chassis Slides.

Model6OllTriaxlnputCable ...................................................................... 3-3

Resistance Source Shielding.

Resistance Source Shielding and Guarding Measuring Resistance Sources Using Model 6191

Model619BlockDiagram..

PowerSupply ................................................................................... 5-2

Electrometer Module Block Diagram

DataBusBuffer ................................................................................. 5-7

Memon/Map IsolatorBoardandSwitches Calibration Cover Supply Calibration ,200mV

Supply Calibration 2 Volt .......................................................................... 6-7

RangeCalibrationZOmA.. ........................................................................ 6-7

RangeCalibration20nA ........................................................................... 6-8

RangeCalibration20kdl ........................................................................... 6-8

RangeCalibrationZOGD

Calibration Fixture Schematic Diagram

Model619lGuardedAdapter ..................................................................... 6-11

IntegratorOutputWaveform

MotherBoard3041lC ........................................................................... 7-31

DisplayBoard32003D ........................................................................... 7-33

Power Supply Board 32004D ..................................................................... 7-37

IEEE Interface Board 30329D

ProcessorBoard32005D

lsolatorBoard32006D

A/D Converter Board 30395D

Electrometer Module Board 30387D

Electrometer Module Board 3039lD

...................................................................................

................................................................................

...........................................................................

.....................................................................

.............................................................

......................................................................

..............................................................

..................................................................

.......................................................................

......................................................................

...........................................................

.......................................................................

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.......................................................................

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....................................................................

...............................................................

Title

............................

...................................................

.....................................................

Page

2-2 2-7 2-8

2.13

3-l 3-l 3-2 3-2 3-3

4-:3

4.:I 4-Z

5-1 5-3

5-10

6-2 6-6 6-7

6-9

6-10 6-12

7-39

7-41 7-43 7-45 7-47 7-49

LIST OF ILLUSTRATIONS (CONT.)

Figure

7-9 7-10 7-11 7-12 7-13 7-14 7-15 7-16 7-17 7-17 7-18

Filter Mux Board 30352D.

Mother Board Schematic 30517D ....................

Display Board Schematic 30515D ....................

Power Supply Schematic 305161)

IEEE Interface Schematic30518D ....................

Processor Schematic (CPU) 30519D Isolator Schematic 3052OD. A/D Converter Schematic 30521 D

Electrometer Module Schematic 305221) ..............

Electrometer Module Schematic 30523D Filter Mux Schematic30524D

..........................

....................

..................

.........................

...................

..............

........................

Title

.....

......

.........

..........

.........

..........

Page

7-51 7-53 7-55 7-57 7-59 7-61 7-63

7-65 7-67 7-69

7-71

LIST OF TABLES

Table 2-1

2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 2-13

Z-14 2-15 2-16 4-I 4-2 4-3 5-l

5-2

5-3

5-4 5-5 5-6 5-7 5-8 6-l 6-2 6-3 7-l 7-2 7-3 7-4 7-5 7-6 7-7 7-8

7-9 7-10

Title Page

MaximumInput ..................................................................................

ExternalFeedbackMeasurements ..................................................................

C,,Selection SecondaryAddress Function

......................................................................................... 2-11

Range Continuous Times (Typical) in Milliseconds One Shot Times (Typical) in Milliseconds (Trigger to First Byte Delay) Operating Function Format DataTerminators..

Data Storage Buffer Commands. Additional Trigger Time to First Byte Time ReadingRateModes

ErrorCodes ....................................................................................

DataCodes ByteDefinitions DCVoltagePerformaceCheck DCCurrentPerformanceCheck

OhmsReferenceCheck ...........................................................................

RegisterCommands RegisterCommands

JumpersforPROMSelection

RegisterCommands .............................................................................

Analog Bus Connector Pin Assignments Valid for Channel A. Analog Bus Connector Pin Assignments Valid for Channel B

ElectrometerControl ............................................................................

Control Data Bit Designations

LineVoltageSelections ...........................................................................

Recommended Test Equipment StaticSensitiveDevices Cross-Reference of Manufacturers.

Display Board PC-514, Parts List ...................................................................

Power Supply PC-515, Parts List

IEEE Interface PC-517, Parts List ..................................................................

CPUBoardPC-518.PartsList .....................................................................

Isolator Board PC-519, Parts List

A/D Converter PC-520, Parts List

Electrometer Module PC-523 and PC-522, Parts List. Filter Mux Board PC-521, Parts List

FanAssembly.PartsList .........................................................................

.................................................................................. 2-10

............................................................................. 2-10

....................................................................................... 2-11

.........................................................

.................................. 2-14

....................................................................... 2-15

............................................................................. 2-16

.................................................................. Z-16

.......... ., .............................................. 2-16

............................................................................ Z-17

.................................................................................... 2-19

................................................................................ Z-20

..................................................................... 4-2

.................................................................... 4-2

.............................................................................. 5-6

.............................................................................. 5-8

......................................................................

..........................................

...........................................

.....................................................................

.................................................................... 6-4

.......................................................................... 6-10

................................................................. 7-2

................................................................... 7-8

.................................................................. 7-15

................................................................. 7-18

.................................................

................................................................ 7-26

2-3 2-5

2-13

2-19

4-2

5-9

5-11 5-16 5-17 5-18 5-19

6-l

7-4

7-10 7-12

7-20 7-30

SECTION 1

GENERAL INFORMATION

1.1 INTRODUCTION The Keithley Model 619 is a fully programmable, micro-

processor based Electrometer/Multimeter. Its broad measurement range is from 2nA. with IOOfA (IO-‘3A) resolution on the most sensitive range, to 2A. The Model 619

ohms measurement range is from 2k (O.lfl resolution) to 2T. The volts measurement range is from 200mV (IpV resolution to ZOOV. The Model 619 is capable of 0.0005%

resolution. It can be interfaced to any programmable measurement system utilizing the IEEE-488 Interface bus.

(See Figures 2-1 and 2-2 for front and rear panel detail.)

1.2 FEATURES

The Model 619 includes the following features:

l Resolution of 4% or 5% is standard with the Model 619.

Resolution of 3% is available only when programmed

through the IEEE-488 bus.

l The IEEE-488 Interface option (Model 6193) enables the

Model 619 to be incorporated into a measurement system

that utilizes programmed control through the IEEE-488

bus.

l The modular construction concept allows for future

developement of a line of interfaceable products.

l Whenever two Model 6194 Electrometer Modules are in-

stalled, there are two separate input channels. Channels A and B measure separately through the READ command and they are separately switched into the AID Converter.

Channel B is an option.

l Ratio A/B takes a ratio of the two channels, always

dividing A by B.

l Difference A-B subtracts the electrometer value of Chan-

nel B from Channel A.

l A beeper sounds whenever a front panel push-button

switch command is given. The beeper is enabled by

Switch 1 on the Isolator Board.

l The Model 6191 Guarded Adapter, in the guarded switch

position, reduces the effect of additional input cable

capacitance (see paragraph 2.2).

1.3 WARRANTY INFORMATION

The Model 619 and its installed options can be returned to

Keithley for repair and calibration. Also, the Model 619 options (Models 6191, 6193, 6194 and 7008) can be returned to the factory without the basic Model 619. Information for returning the Model 619 and/or its options is given on the inside front cover of this instruction manual.

1.4 MANUAL ADDENDA Improvements or changes to this manual will be explained

on an addendum attached to the inside back cover.

1.5 SAFETY SYMBOLS AND TERMS Safety symbols used in this manual are as follows:

The symbol

on the instrument denotes that

the user should refer to the operating instructions. The symbol

IOOOV or more may be present on the terminal(s.1.

‘t

on the instrument denotes that

The WARNING used in this manual explains dangers that

could result in personal injury or death.

The CAUTION used in this manual explains hazards that

could damage the instrument.

1.6 UNPACKING AND INSPECTION The Model 619 was carefully inspected both mechanically

and electrically before shipment. Upon receiving the Model 619, unpack all items from the shipping container and check for any obvious damage which may have occured during transit. Report any damage to the shipping agent. Retain and use the original packaging materials if reshipment is required. The following items are shipped with all Model 619 orders:

l Model 619 Electrometer/Multimeter with one Model 6194

Electrometer Module and one Model 6011 Triax Input

Cable. Model 619 Instruction Manual. Installed or separate optional accessories per request. Warranty Card(s).

Warranty information is given on the inside front cover of this instruction manual. If there is a need to exercise the warranty, contact the Keithley representative in your area to determine the proper action to be taken. Keithley maintains service facilities in the United Kingdom and West Germany, as well as in the United States. Check the inside front cover of this manual for addresses.

7 SPECIFICATIONS .;

For Model 619 detailed specifications, refer to specifications

that precede this section.

l-l/l-Z

SECTION 2

OPERATION

2.1 INTRODUCTION This section contains information concerning unpacking, in-

sepection, initiil use and operation of the Model 619.

2.2 PREPARATION FOR USE The Model 619 is shipped ready for use on the line voltage

marked on its rear panel. The beeper is programmed to be operational, and if the Model 6193 IEEE-488 Output is installed, it will be set to the Addressable mode, binary address 6 ~001101.

NOTE

The following procedure can be used to either confirm the factory setting or to set up the instrument for other modes of operation.

2.3 PRE-POWER UP PROGRAMMING The top cover of the Model 619 must be removed to check

or change the LINE VOLTAGE, LINE FREQUENCY, and

BEEPER switches. To remove the top cover, refer to Sec-

tion 6 Maintenance.

2.4 POWER UP During power up, all LED annunciators, other than seven-

segment displays, will momentarily light indicating they are functioning properly, and the Model 619 will go to the default conditions given in paragraph 2.27.

During power up, the Model 619 will do a RAM test using test patterns. If the RAM test fails, the bad chip will be indicated by a blinking annunciator as follows.

LOW High LOW High

During power up, the Model 619 will do a cyclic redundance

check (CRC) on its PROM memory. If PROM test fails, it will

be indicated by blinking annunciators as follows:

During power up the Model 619 displays the current soft-

wars revision level and line frequency selected as follows:

Frequency Designation: F60 for 60 Hz

BYTE BYTE BYTE BYTE

CHANNEL, CH 9, RATIO, DIFF

LOW lk RAM LOW lk RAM High lk RAM U922 RATIO High lk RAM

F50 for 50 Hz

u919 CH.A U920 CH.6

U923 DIFF

(All Blinking)

Current Software Revision Level: C-2

c-2

During power up, the Model 619 will check the operation of

each module in the unit as follows:

1. If Channel A is not present or malfunctions, “no ch-A” will be displayed.

2. If Channel 6 is not present or malfunctions, “no ch-6” will be displayed.

3. If the FilterlMux or A/D are either not present or they

malfunction,

4. If the Isolator is not present or malfunctions, “no ISO” will be displayed.

During operation, the Isolator is doing error checking on data going across the Isolator.

In sending data, if after eight retries the data is not sent correctly a “SND E” will occur and the transmission is attsmpted again eight more times. This process continues until the data is correct.

In receiving data, if after sight retries the data is not received correctly, “REC E” will occur and the reception isattempted agin eight more times. This process continues until the data is correct.

2.5 BEEPER SELECTION

When a button is depressed and the Model 619 circuitry recognizes it, the beeper will sound momentarily. Illegal conditions not recognized by error messages will not beep (i.e., highest range and uprangel.

The beeper is programmed to be operational at the factory; however, it can be disabled if so desired. To disable the beeper, refer to Section 6 Maintenance.

2.6 TALK ONLY MODE/ADDRESSABLE MODE SELECTION (see Figure 2-l)

If the Model 6193 IEEE-488 Output is installed, it will be factory set to the Addressable mode at binary address 6. When in the Addressable mode, RATIO A/B and DIFFERENCE A-B are disabled. A different address can be selected by setting switches Al through A5 of 5701 and putting the Model 619 through the power up cycle (see Note). The switches permit five-bit binary selection of addresses 0 to 31.

The Talk Only mode can be selected by setting switch 7 to the closed 10) position and putting the Model 619 through the power up cycle lses Note). When in the Talk Only mode, the address switches are disabled. In this mode the TALK ONLY and TALK LED’s will light.

“no A-d” will be displayed.

NOTE

2-1

NOTE

In order for the Model 619 to accept an address or mode change, the instrument must

go through the power up cycle. If the Model 619 is already on, turn it OFF and then back to ON.

2.7 READING RATE SELECTION

When the Model 619 is in the Front Panel mode and the 5% digit re$olution mode, two different reading rates can be chosen via 55 (2.41 rdg/sec) or SE (0.30 rdg/sec). See Table 2-6. To select the 55 reading rate, refer to Section 6 Maintenance.

2.8 OPERATING INSTRUCTIONS

Table 2-l. Maximum Input

Range 200mV. 2V

Maximum Input

250V RMS, DC to 60Hz sineware

ZnA, 20nA. 200nA 2pA. 20pA. 200pA

ZmA, 20mA 2A

250V RMS, DC to 60Hz sineware

250V RMS, DC to

60Hz sineware,

Fuse Protected

2kn. 20kQ. 200kn 2Mfl. ZOMR, 200M11

ZGO, ZOGQ, 200Gn 2TD

250V RMS, DC to 60Hz sineware

The basic operating instructions for the Model 619 are outlined in the following paragraphs, Variations and more complicated measurements will be described later in this section.

1. The Model 619 is provided with a three-wire line cord which mates with third-wire grounded receptacles.

WARNING

Ground the instrument through a properly earth-grounded receptacle before operation. Failure to ground the instrument can result in severe injury or death in the avant of short circuit or malfunc-

tion. In addition, connect only to the

line voltage selected. Application of incorrect voltage can damage the in-

strument.

2. Turn on the power by depressing the ON/OFF push button in the lower left-hand corner of the front panel (see

Figure 2.2). Allow one hour for warm up. An additional hour may be required for temperature extremes. Note that the rear panel power switch must also be in the ON position.

3. Upon power up, the Model 619 will go to the default conditions and a beeper will sound for approximately two seconds, The selected frequency and software revision level will also be momentarily displayed. To change any of the default conditions, refer to paragraph 2.27. Input connectors are located on the rear panel of the Model 6194 Electrometer Module. The main input is in the triax connector, with a separate input for the 2 Amp range. An Analog Output is provided for convenience on a DIN con-

nector (refer to Figure Z-21. Connect the measurement source to the input terminals and make the desired measurement. See Table 2-l for maximum input.

2.9 FRONT PANEL FUNCTIONS

The Model 619 Front Panel has two funCtiOnal groups. an Annunciator and Display Group and a Function Saiectqr

Group. See Figure 2-2.

2.9.1 Annunciator and Display Group

The software or manually selected status of the Model 619 may be determined at any time by looking at the Annunciators. There are four Annunciator Groups; Status Blocks A, B, C and D.

1. Status Block A indicates the channel status as either Channel A, Channel B, Ratio A/B, or Difference A-B.

2. Status Block B indicates the status of other functions including,

Zero Check, Suppression, Auto Range, Filter,

Trigger, Update, and External Feedback.

,3. Status Block C indicates the IEEE-488 bus status as

Remote, Listen, Talk, SRQ, Binary, Talk Only, or LLO.

4. Status Block D indicates the measurement; Volts, Amps, or Ohms.

The E-Digit Display next to Status Block D indicates the measured value, power, and sign of the input to the Model 619 ElectrometeriMultimeter. In addition to these Status Blocks, status may also be determined by controller sampling through the IEEE-488 bus.

2.9.2 Function Selector Group

The Function Selector Group consists of seven blocks; Dual

Channel including Ratio and Difference, Volts-Amps-Ohms, Range Selection, Zero Controls, Baseline Controls, Filter,

and Resolution.

NOTE

Note that all front panel operations described below, except Ratio and Difference, may be programmed or controlled from the IEEE-488 bus using the optional Model 6193 Interface. In Remote (or Manuall mode, the Model 619 front panel selector push-button switches are active unless LLO is commanded through the bus.

2-3

2.9.3 Dual Channel Whenever the Model 619 has a second Model 6194 Elec-

trometer Module installed, Channel A or B may be selected from the front panel or bus. The two channels are independent so that they operate as two separate instruments and

can be separately programmed.

1. Channel A A. Upon power up of the Model 619, CHANNEL A will be

displayed in the Channel Status Block.

B. Otherwise, depressing the CHANNEL A push button

will:

(a) Display CHANNEL A data. lb) Light the CHANNEL A annunciator.

2. Channel B A. Depressing the CHANNEL B push button will:

(a) Display CHANNEL B data. (b) Light the CHANNEL B annunciator.

B. If there is no Channel B installed in the Model 619,

depressing the CHANNEL B push button will:

la) Display the error message “no ch-b.” (b) ReIeit-: the Model 619 to the previous operating

3. Ratio A/B and Difference A-B. In any Function or Range the Ratio or Difference between Channel A and B, from

10-1s to IOf’s, may be calculated and displayed.

NOTE

The Model 6193 IEEE-488 Interface must be

in the Talk Only mode or else not installed

for Ratio and Difference operations.

1. Light the DIFFERENCE A-B annunciator.

2. Take one reading at 4.8rdglsec rate on Channel A.

3. Take one reading at 4.8rdglsec rate on Channel

4. Compute the difference.

5. Display the difference at a 2.4rdg/sec rate, with a 5%.digit resolution.

6. Repeat the above seauence.

DIFFERENCE A-B push button will:

1, Display the error message “no ch-b.”

2. Return to the previous operating mode.

NOTE

Observe that the largest value that can be displayed in the Ratio or Difference mode is

1999.99 x 10’s. The smallest value that can be displayed is 0.00000 x 10-1s. Any time a

division by zero is attempted, the display message is “OFLO” (overflow). The data used internally by the Model 619 is to a higher resolution than the displayed reading.

Therefore, a display of all zeros on Channel

B will not necessarily result in a RATIO

“OFLO.”

2.9.4 Volts, Amps, and Ohms Volts, Amps.

Ohms functions may be manually selected for a wide range of measurements. Programmed or software selected may also be obtained through the IEEE-488

Interface bus.

A. Ratio A/B

(a) If the Model 819 is in the Addressable mode, the

RATIO A/B command is locked out and cannot be selected.

(b) Otherwise, when the RATIO A/B push button is

depressed the Model 619 will:

1. Light RATIO A/B annunciator.

2. Take one reading at 4.8rdglsec rate on Channel A.

3. Take one reading at 4.8rdg/sec rate on Channel

4. Compute the ratio.

5. Display the ratio at 2.4rdg/sec rate with 5% digit resolution.

6. Repeat the above sequence.

RATIO A/B push button will:

1. Display the error message “no ch-b.”

2. Return to the previous operating mode.

B. Difference A-B

(a) If the Model 619 is in the Addressable mode, this

command is locked out and cannot be selected.

(b) Otherwise, when the DIFFERENCE A-B push but-

ton is depressed the Model 619 will:

NOTE

In resistance and voltage modes, analog output is noninverted and can be used for

guarding.

I. Volts

A. Upon oower up the Model 619 will go to the Volts

function.

B. If the Model 619 is in the Ratio A/B or the Difference

A-B mode, this command is locked out and cannot be selected.

C. Otherwise, selecting the Volts function for the

rently displayed channel will: (a) Light the VOLTS annunciator. (b) Program the Electrometer for the Volts function.

2. Amps A. If the Model 619 is in the Ratio A/B or the Difference

A-B mode, this command is locked out.

B. Otherwise, selecting the Amps function for the cur-

rently displayed channel will: (a) Light the AMPS annunciator. (b) Program the Electrometer for the Amps function.

cur-

2-4

Ohms A. If the Model 619 is in the Ratio A/B or the Difference

A-B mode, this command is locked out.

B. Otherwise, selecting the Ohms function for the cur-

rently displayed channel will: (a) Light the OHMS annunciator. (b) Program the Electrometer for the Ohms function.

2.9.5 Range Selection

1. Auto/Manual A. Auto or manual range may be selected by pressing

the appropriate front panel button or by programming on the Interface bus.

8. If the Model 619 is in the Ratio A/B or the Difference

A-B mode, this commend is locked out.

C. If the channel currently being displayed is in AUTO

RANGE. deoressina the AUTO/MANUAL oush button will:’ (a) Turn off the AUTO RANGE annunciator. (b) Place Model 619 into Manual Ranging.

(4 Then hold the present range.

D. If the channel currently being displayed is in Manual

Ranging, depressing the AUTO/MANUAL push button will:

(al Light the AUTO RANGE annunciator.

(b) Begin Auto Ranging.

(cl Hold the previously displayed reading until settled

range is found, then display it.

E. The following ranges cannot be accessed in the Auto

Range mode and actuation of Auto/Manual in any of these function range combinations will result in an error display of “noAU”:

(a) 2 Amp Range. This range requires a separate

input. (b) External Feedback (Amps Function). (4 2G Ohm through 2T Ohm Range. These high

resistances require long time constants.

2. Uprange/Downrange. Manual ranges are advanced up or down by pressing the appropriate front panel button. The desired range may also be programmed on the Interface bus. A. Uprange

(a) If either RATIO A/B or DIFFERENCE A-8 is

selected, this command is locked out and cannot be accomplished.

(b) If the channel currently being displayed is in

AUTO RANGE, depressing the UPRANGE button will place the Model 619 is Manual Ranging and

advance Uprange one step.

MANUAL RANGE, depressing the UPRANGE push button will advance Uprange one step.

(d) If the channel currently being displayed is in

MANUAL RANGE and on the highest possible range for that function, depressing the UPRANGE push button will be ineffective.

B. Downrange. Downrange operates in the same manner

as Uprange.

C. External Feedback. External Feedback is accessible on

Amps function by touching or programming

UPRANGE on the 2 Amp range. (a) If the displayed channel is in AMPS and Range 20

(range above the 2 Amp range), the Model 619

will:

1. Place the Electrometer in the Ext Feedback mode.

2. Light the EXT FEEDBACK annunciator.

(b) All status which were in effect for Range 8 in

AMPS are in effect for EXT FEEDBACK.

made on the Amps function by programming or touching UPRANGE beyond the 2 Amp range.

NOTE

When using a resistive feedback configura-

tion either linear (resistor) or non-linear (log diode junction) additional parallel capacitance will be required for stable opertion. See External Feedback Use, paragraph 2.10, also see Keithley App. note #IO1 “Using the

619 External Feedback.” Analog output will invert in the Amps func-

tion, but will not in Volts of Ohms functions.

Output levels and gain are given in full

specifications.

(d) The AID Converter inverts and displays Vout on

the 2 Volt range.

Table 2-2. External Feedback Measurements

Connect these components

In Order to Meawn

between the Input and Analog Output

Capacitor

V,,t = -Q/C

Logarithmic Currents

Log Diode

V O,,t= -lK Log I + constant)

Current Gains

2.9.6 Zero Controls

Non-Decade Resistors, R

=-IR

When there is voltage offset which must be compensated in

making precision measurements, this compensation is automatic using the ZERO CORRECT push button (or by Interface bus command). Compensation corrects for offsets on ranges within the selected channel and function.

2-5

1. Zero Check A. If the displayed Channel (A or B) is not currently in

ZERO CHECK, depressing the ZERO CHECK push

button will: (a) Program the Electrometer to Zero Check. (b) Light the ZERO CHECK annunciator.

B. If the displayed Channel (A or B) is currently in ZERO

CHECK, depress the ZERO CHECK push button, and

the Model 619 will:

(al Turn off ZERO CHECK annunciator. (b) Program the Electrometer out of Zero Check.

C. If the displayed channel is in AMPS, Range 9,

depressing the ZERO CHECK push button will display the error message “no 2AC” (no Zero Check in 2 Amp

range).

2. Zero Correct

A. If either RATIO A/B or DIFFERENCE A-B is selected,

this command is locked out and cannot be accomplished.

8. If the Model 619 is not in ZERO CHECK or is 2 Amp current range, depressing the ZERO CORRECT push button will: (a) Display the error message “corr IL” (b) Then return to the previous operating mode.

C. If the Model 619 is in ZERO CHECK, depressing the

ZERO CORRECT push button will: (a) Disable the filter.

(b) Put the AID Converter in times 10 gain mode and

in a 16.66msec integration period. (cl Average 2 conversions. (d) Take a reading with the Electrometer attenuator in

- 1 and then - 10. (a) Solve for Electrometer and A/D offsets. (f) Repeat above steps for IOOms integration time

period.

(g) Return to previous operating mode in Zero Check,

compensating for all internal voltage offsets

measured during Steps a through f.

2.9.7 Baseline Controls

(a) Store the current reading in the Baseline register

assigned to the currently displayed Channel/Function. There are six Baseline registers: Channel A/Volts, Channel A/Amps, Channel A/Ohms,

Channel B/Volts, Channel B/Amps, and Channel

B/Ohms.

fb) If in Baseline Suppression mode, take unit out of

Baseline Suooression. which will turn off the BASELINE SUPPRESSION annunciator.

fc) Return to previous operating mode (except

Baseline Suppression).

2. Baseline Suppression A. If either RATIO A/B or DIFFERENCE A-B is selected,

this command is locked out.

If the Model 619 is not currently in the Baseline Suppression mode, depressing the BASELINE SUPPRESSION push button will: (a) Light the BASELINE SUPPRESSION annunciator. tb) Subtract from display the contents of the ap-

propriate Channel/Function Baseline register (e.g., if 0.10 volts is stored in the Channel B/Volts Baseline register, subtract 0.10 Volts from readings on all Channel B voltage ranges).

If the Model 619 is currently in the Baseline Suppres-

sion mode, depressing the BASELINE SUPPRES-

SION push button will: Ia) Take unit out of Baseline Suppression. lb) Turn off the BASELINE SUPPRESSION annun-

ciator.

WARNING

If the Model 619 is in the 200 Volt range and in Basline Suppression, the

BASELINE SUPPRESSION annunciator will blink indicating a safety warning. A dangerous voltage level could exist and still be read es a lower voltage as displayed by the instrument. This could present a shock hazard should the

operator misinterpret the measurement

relative to actual voltage.

Baseline Controls assist in making relative measurements es referenced to a known value (leakage, operating parameters, etc.). The Model 619 will subtract this amount on all ranges on the particular channel where a baseline is assigned.

WARNING

The Suppression light will blink on the 200 Volt range, indicating e possible

high voltage safety hazard.

1. Baseline Store A. If either RATIO A/B or DIFFERENCE A-B is selected,

or the instrument is currently displaying “OFLO,” this command is locked out and cannot be accomplished.

B. Otherwise, depressing the BASELINE STORE push

button will:

2-6

2.9.8 Filter

When the Filter is placed in operation, by pressing the

FILTER push button or commanding it through the IEEE-488 Interface bus, an additional 25dB of line frequency

rejection filtering is applied.

1. If either RATIO A/B or DIFFERENCE A-B is selected, this command is locked out.

2. If the displayed channel is not currently in the Filter mode, depress the FILTER push button and the Model

619 will:

A. switch the Filter in. B. Light the FILTER annunciator.

3. If the displayed channel is currently in the Filter mode, depressing the FILTER push button will: A. Switch the Filter out. B. Turn off FILTER annunciator.

2.9.9 Resolution

Pressing the RESOLUTION push button provides an extra

decade of sensitivity and resolution. This may also be ac-

complished, by command, on the IEEE-488 Interface bus.

NOTE

For example, the 2nA range, in Resolution, will go from 4% digit, 100Fa. Isd, to 5% digit, 1OfA Isd resolution. Noise is typically a few digits in the fifth place.

1. If either RATIO A/B or DIFFERENCE A-B is selected, this command is locked out.

2. If the Model 619 is currently displaying the 4% digits, depressing the RESOLUTION push button will: A. Reduce the reading rate to 2.4rdg/sec.

B. Increase the display resolution to 5% digits.

3. If the Model 619 is currently displaying 5% digits, depressing the RESOLUTION push button will: A. Increase the reading rate to 5,49rdg/sec.

B. Reduce the display resolution to 4% digits.

2.9.10 Current Ranges, Common Input

Whenver a common input is required, which would include the 2 Amp range, the following triax adapter may be utilized. In this instance, a single input is used and an external relay connects the 2 Amp current range shunt to the triax input connector on the Model 6194 Electrometer Module. See Figure 2-3.

A 5 Volt control signal, external to the Model 619 Electrometer/ Multimeter must be supplied to switch the relay to the 2 Amp current range. Any additional leakage current introduced by the relay can be nulled using the BASELINE STORE/BASELINE SUPPRESS feature.

WARNING

Care should be exercised in shielding the input from any extraneous pickup. Additonally, if a high common mode voltage is required, the entire circuit should be shielded by the chassis

ground to prevent a potential shock hazard.

NOTE Displayed exponents are multiples of three (0, *3, i6, *12, *15, *181. The Resolu-

tion feature increases only the resolution of

the displayed reading.

I- -

INPUT COMMON >

CHASSIS GROUND >

. \

------

CONTROL

2.10 EXTERNAL FEEDBACK USE

The external feedback current range provides a varied and extensive additional measurement capability to the Model 619 Electrometer/Multimeter. Among these are charge, logarithmic currents, and non-decade current gains.

PlOO

I I

TRIAX INPUT

6194

2 AMP

INPUT

RYlOO

5100: KEITHLEY es-253

(POMONA #358Ol

PlOO: KEITHLEY CS-141

(SPECIALTY CONNECTOR CO. #3OP-100.11

FlYlOO: KEITHLEY AL-51 (5V-500)

Figure 2-3. Common Input Current Range

2-7

The input circuitry used in the Model 6194 Electrometer in the Amps function is configured in the feedback Amps mode as illustrated in Figure 2-4. An input currant applied at the negative input of the op amp is nulled with a current through the parallel combination of R,, ,and C,, from the output of the op amp. This is accomplrshed by the high open-loop gain (typically greater than 40,000) of the op amp which holds its negative input at virtual ground (its positive input which is connected to input common). R,, in parallel with C,, converts the input current to a voltage which is further processed by the AID Converter in the Model 619.

Included in this processing is a reinversion of the signal polarity to match that of the actual input.

parallel combination of the two quantities separated by this symbol (AlI B)=AB/fA + Bl).

5. Selection of the external feedback network must incorporate the proper frequency compensation required by the Model 6194 Electrometer Module.

6. All external feedback circuitry should be housed in a suitably shielded enclosure. Insulators supporting the input node (input HII should be constructed of Teflon@

other high quality insulator.

2.10.1 External Trigger

When the Model 619 is turned on it is in the continuous mode To. When switch S3 (Figure 6-1, Isolator Board) is switched to ON and the, Resolution button is pressed the Model 619 is placed into the one shot mode Tl. The Tl mode allows a trigger only from the front panel by pressing the Ratio/Difference button or by the External Trigger.

The external trigger requires a falling edge pulse at TTL logic levels. The trigger voltage should be between, greater than Or equal to zero, and less than or equal to + 5 volts. The external trigger pulse initiates a measurement conversion, For one shot (Tl, T3 and T5) times (trigger to first byte) refer to Table 2-8. For continuous ITO, T2 and T4) times refer to

Table 2-7.

Figure 2-4. Model 6194 Electrometer Input Circuitry

The availability of the analog output permits the user to

substitute an external network for the combination of R ,and C,,. In effectively applying the capability, a number o F factors must be taken into account.

1. The total absolute value current supplied by the analog output for both feedback to the input and monitoring of

the analog output must be less than 22mA.

2. The Model 619 processes the Model 6194 Electrometer output as a i2.OOOOVDC f *2.00000VDC in the 5% digit mode) signal correctly inverting the polarity for an accurate representation of the input signal polarity. This output voltage is the level impressed across the external

feedback network.

3. Accuracy of the response is the same as that for the 2 Volt range, excluding the contribution of all user-supplied external feedback circuitry. Noise and NMRR will also be a function of this external circuitry.

4. Input impedance is given by the relationship z - 0.5MD 11 (Z /A ), where ZFB is the external feedb!!ckietwork and xv is”tha open-loop gain of the op amp (typically greater than 40,000). Note that in Zero Check, A” is reduced to unit” Ill and that /I represents the

NOTE The external trigger is inhibited in the SO mode or by LLO (local lockout).

Electrometer Complete-The Electrometer Complete output is a 400~s~ wide positive pulse that signifies completion of the measurement conversion cycle. The Electrometer Complete line can be used to trigger another instrument or to in-

form an instrument that the measurement conversion cycle

has been completed. For example: The Model 619 can be used with a scanner.

The Electrometer Complete line can trigger the scanner to

switch to the next available channel when the Model 619 measurement cycle has been completed.

2.10.2 Charge

The measurement of charge can be made directly by using an external feedback capacitor, C,,, as illustrated in Figure 2-6. In the relationship Cl= CV, Q= charge (coulombs) applied to input, C=capacitance (farads) of Cr. and V= voltage (volts) at output as indicated on the display. The Model 619 display will read charge directly in the units determined by C. For example, using IpF capacitor will provide a display in pC.

In practice, C,, should be greater than 1OOpF for feedback

stability and of a suitable dielectric material to ensure low

leakage and low dielectric absorption. Polystyrene and

2-g

polypropylene dielectric capacitors offer good performance in this regard.

As shown in Figure 2-5 an external Zero Check contact may be desirable in certain applications where 0.5MQ Zero Check input impedance cannot be tolerated. R,,,,, protects this contact from the discharge surge of C, Care should be ax ercised in the selection of this contact switch or relay) that

the high impedance, low current requirements of the circuitry are not compromised.

From this equation, proper selection of transistor 01 (Figure 2-6) would require a device with a high current gain (h,,) which is maintained war a wide range of emitter currents. Suitable devices include Analog Devices AD812 and Precision Monolithics MAT-Ql.

Frequency compensation/stabilization is accomplished by C,,. Selection of a proper value depends on the particular transistor being used and the maximum current level anticipated. Compensation at the maximum current is required since the dynamic impedance of the transistor will be a minimum at this point. It should be noted that the response speed at lower currents will be compromised due to the increasing dynamic impedance.

Z (impedance) = 2V/21= kT/ql=O.O26/1 @25OC

Using the MAT-01 or AD818, a minimum RC time constant of 50@ec at maximum input current should be used. At I,,(maxl of 100/1A, this would correspond to 0.2pF. Note that at lOOnA, this would increase the RC response time constant to 50msec (5sec at InAl. A minimum capacitance of IOOpF is recommended.

Figure 2-5. Charge Measurement

2.10.3 Logarithmic Currents The use of a diode junction in the external feedback path

permits a logarithmic current-to-voltage conversion. This relationship for a junction diode can be given by the equation:

V=m kT/q In (I/lol+lR,

where q = unit charge (1.6022x10-‘90, k= Boltzmann’s

constant ~1.3806x10-*~J/°Kl, and T= Temperature (OK).

The limitations in this equation center on the factors I,,, m, and Rs. lo is the extrapolated current for V=O. An empirical

proportional constant, m, accounts for the different character of currant conduction (i.e. recombination and

diffusion) mechanisms within the j&ion, typically varying

in value between 1 and 2. Finally, R, constitutes the ohmic bulk resistance of the diode junction material. lo and Rs limit

the usefulness of the junction diode as a log converter at

low and high currants, respectively. The factor m introduces non-linearities between these two extremes. With all these

factors taken into account, most diodes have a limited range

of useful logarithmic behavior.

A solution to these constraints is the use of a transistor configured as a “transdiode” in the feedback path as shown in

Figure 2-6. Analyzing the transistor in this configuration leads to the relationship:

V= kT/qllnl/lo-In (h&(1 + h,,)ll

where H,, is the current gain of the transistor.

Although the input to this configuration is a current source, a voltage source can be used with a suitable ballast resistor. In this configuration, the input burden of ImV must be considered as an error s~ource against the input voltage.

Further processing of the response can be accomplished with Baseline Suppression and Ratio. Baseline Suppression provides an offset and Ratio provides a scaling factor (with optional Channel B, Model 6194 Electrometer Module installedl. Alternately, a controller (computer) can process the data via the IEEE-488 bus output (with optional Model 6193 IEEE Interface installed).

Figure 2-6. Logarithmic Current Measurement

2.11 NON-DECADE CURRENT GAINS The Model 6194 Electrometer uses internal decade

resistance feedback networks for the 2nA through 20mA currant ranges. In some applications a non-decade currentto-voltage conversion (gain) may be desirable. As illustrated in Figure 2-7 a calibratable resistance, R,,, serves this purlXXe.

2-9

not in the remote mode, the first arguments preceding the remote mode will not program the Model 619 and will cause “NO rN” to be displayed. The Model 619 front

panel push-button switches will respond unless LLO is commanded through the bus. Pressing the RATIO button

initiates a conversion(s) if a trigger is being awaited by the Model 619 (the RATIO button is a manual trigger dur-

ing bus operation). After programming, the front panel does not reflect the new configuration until the Model 619 is triggered.

Table 2-4. Secondary Address

Figure 2-7. Non-Decade Current Gain Measurement

Limitations on the value of R,, require it to be in the range of 102n to 10’00. Frequency compensation/stabilization is accomplished by C,,. Selection of C,, based on an RC

response time should be per Table 2-3 with a minimum value of IOOpF:

TABLE 2-3 C,, SELECTION

2.12 SYSTEM OPERATION (Using the Model 6193 IEEE-488 Interface)

2.13 ADDRESS SELECTION

1. Primary Address. The Primary Address of the Model 619 is selected by 5 switches on the IEEE-488 module (see Figure 2-l). These switches are accessible from the rear panel of the unit. This allows the selection of 31 primary listener/talker address pairs. Binary 11111 is reserved for the Untalk and Unlisten commands.

2. Secondary Address. The Model 619 uses a secondary addressing to distinguish between SRQ requests, commands and data associated with input Channel A and input Channel B. To address the Model 619, the IEEE-488 controller must send the primary address of the Model 619 followed by the secondary address of the desired channel. See Table 2-4 for secondary addresses.

2.14 BUS MANAGEMENT LINES

FUNCTION

Channel A (LISTEN)

ASCII HEX

;;”

Channel A (TALK) Channel B (LISTEN) Channel B (TALK1 SRQ (TALK) Status Request A (TALK) Status Request El (TALK) ii 64;

i 62; b

f 3

63H

-I

2. Interface Clear (IFC). Clears the Interface and goes to talker/listener idle states. There are no state (function, range, etc.) changes in the Model 619.

3. Service Request (SRQ). Requests serial poll service.

4. End (EOII. Asserted during last byte of multi-byte data transfer.

5. Attention (ATN). Asserted when address or commands are present on the bus.

2.14.1 Bus Commands Implemented

1. Universal Commands A. Device Clear (DCL). The Model 619 goes to default

conditions (see paragraph 2.27)

B. Local Lock Out (LLOI. If LLO is given, the front panel

controls cannot cause a change in status in the Model

619. (The LLO annunciator will light when in LLO).

C. Serial Poll Disable (SPD). Disables serial polling.

D. Serial Poll Enable (SPE). When addressed to Talk, the

Model 619 will send the SRQ status word.

E. Untalk (UNTI. Puts the Model 619 into a talker idle

state if it was a talker.

F. Unlisten (UNLI. Puts the Model 619 into a listener idle

state if it was a listener.

1. Remote Enable (REN). To place the Model 619 into the remote mode, send REN and the appropriate listen ad-

dress and the remote indicator will light. The statement

used to enter the remote mode (i.e. REN end Address) must not contain any other commands. The Model 619 must be in the remote mode to be programmed. If it is

2-10

2. Address Commands A. Selected Device Clear (SDC). If the Model 619 is ad-

dressed to listen it will go to default conditions.

B. Group Execute Trigger (GET). If the Model 619 is ad-

dressed to listen and in the proper trigger mode (T2 or T3). it will automatically trigger a conversion.

2.14.2 Input Channel Control (Secondary Address is a or bl

1. Channel. Input Channels A and B can be separately ad-

dressed and controlled using secondary addressing. Each input channel has several internal status words which define the current operating status of the channel. When

addressed to Talk, the status words define the function,

range, and mode of operation by which the data will be accepted. The status words can be modified by the

following device dependent commands sent via the bus

(see Status Section). In order to program Channel A or Channel 8 the machine must be in Remote mode.

2. Device Dependent Commands. The following device dependent commands apply to either Channel A or Channel B as defined by the secondary address. Any or all may be used followed by an execute command “X” to

inititate the change. Only after the execute command will the change take place. Commands may also be sent in sections, for example:

First Commands Send Fl

Second Command Send R2X The above commands are the same as sending Fl R2X in one command. A. Function and Range. Refer to Tables 2-5 and 2-6 for

function and range information.

B Bus Response Mode

(a) Mg Standard. On error or data, the Model 619 will

not access SRQ (status byte will still contain up-

to-date information if serial poll done).

(b) Ml Interrupt. On error or data, the Model 619 will

access SRQ when appropriate.

C. Trigger Mode (same for both Channels A and B)

(a) T@ Continuous on Talk. The Model 619 con-

tinuously updates the display at the programmed’ reading rate after being address to Talk. The output data buffer will be updated at the same rate as

the display if the data is read out at the same rate.

If the data is not read out, the reading will be held in the output data buffer until it is read out. When it is read out, the next value will then be placed in the buffer.

(b) Tl One-Shot on Talk. The Model 619 will update

the output data buffer at the programmed rate, once each time a conversion is initiated by being addressed to Talk (to retrigger, address to Talk again) (see Figure 2-B).

(c)

T2 Continuous on GET. The same as Continuous on Talk except it is done on GET (see Figure 2-B).

(d) T3 One-Shot on GET. After a GET command is ac-

cepted by the Model 619, it will initiate a conversion. The Model 619 will update the output data

buffer once at the oroarammed reading

rate (see

Figure 2-B).

(a) T4 Continuous on X. The same as Continuous on

Talk except it is done on X (see Figure 2-B).

(fl T5 One-Shot on X. After an “X” command is

accepted by the Model 619, it will initiate a conversion. The Model 619 will then update the output data buffer once at the programmed reading rate

(see Figure 2-81.

(g) Pwr ON/DCL/SDC, Default T@.

Table 2-5. Function

Power ON/DCL/SDC, Default F@

Table 2-6. Range

Volts

Auto

200mV 2v 2ov 2oov

*2oov

2oov

*2oov

2oov

__IN/DC

Amps Auto

2nA 20nA 200nA

W 20fiA 2OOfiA

2mA 20mA

2Amps

**EXT FEEDBACK

SDC, Default R4

Ohms

Auto 2k 20k 200k 2M 20M 200M “2G “20G 200G “2T

*Will not autorange into these ranges **EXT FEEDBACK is considered to be an Amps range and

not an individual function.

2.15 DATA FORMAT

1. D@ ASCII Data String. The internal Model 619 priorities are such that ASCII data is passed to the interface after the display is updated (same for Channels A and 6).

2. Dl Binary Data String. The internal Model 619 priorities

are such that Binary data is passed to the interface before going to the display. The display will be blank except for bus annunciators.

2.16 ASCII FORMAT

Channels A and B can be separately addressed to talk using secondary addresses a and b. When the Model 619 is addressed to Talk, it will transmit the current contents of its output data buffer as a 16 to 18 byte ASCII string. The actual length of the ASCII string depends

the

number

of programmed terminators. Refer to Figures 2-9 and 2.10 and Tables 2-7 through 2.9.

2.17 BINARY FORMAT (Refer to Figure 2-11)

1. In the binary data mode, the Binary annunciator will turn ON and the display becomes blank except for the bus an-

nunciators.

2-11

Figure 2-8. Timing Diagram

Table 2-7. Continuous Time (Typical1 in Milliseconds

RATE

SO Sl S2 S3

t) in m*ec 1

Sl -

s3 I

54 - SE

Figure 2-9. Start of Signal Integrate from Trigger Itl)

(Trigger is a negative going pulse.)

Table 2-8. One Shot Times ITypical) in Milliseconds I%,,)

* ATNxto DAVX

** ATN

to SRQ

5 7L

z-13

2. Byte 1: (Refer to Figure 2-10) A. Sign Bit - 1 = negative, 0 = positive

B. Overflow Bit 1 =overflow C. Data bits Most significant 6 bits of absolute value

binary data.

3. Byte 2,3: 16-bit binary data.

4. Byte 4: 2’s complement binary representation of decimal

exponent.

5. Binary Format is not available in “Talk Only” mode.

6. Binarv Format is not defined for secondary channels C

Bus Line EOl is asserted during transmission of the last byte (Dummy byte).

2.18 PROGRAMMABLE TERMINATOR

1, The Model 619 utilizes the ASCII Code for terminating

data transfer, see Table 2.10. The Model 619 is program-

med with a CR LF terminator that is designated as Y (LFI when sent over the bus.

Table 2-9. Operating Function Format

2. However, a different terminator can be programmed into the Model 619. Example: To use A as a terminator, pro-

gram Y IA) to be sent over the bus. Reserved letters are not usable as terminators.

3. No terminator is used if a Y (DEL) is Sent over the bus. The EOI will identify the last byte of the data transfer.

4. On power up of the instrument, the default condition

puts the Model 619 back into the CR LF terminator mode.

2.19 BUFFER READINGS Wnne for both Channels

A and Bl

Data Storage Buffer commands for buffer contents are

shown in Table 2-11.

Q(ASCII): The (ASCII) byte contains an ASCII number from

0 to 5. This number will allow l-50 readings ‘7” to be stored

going in groups of 10 readings. I, (ASCII) = 1 says that ‘7” equals 10 readings (i.e., 01

says that “T” equals 10 readings).

FUNCTION DATA

Volts

Amps Ohms

Ratio** Difference**

““Availble in “Talk Only” operation only. *N = Normal Reading

0 = Overflow Reading

*NDVC * 1. 2 3 4 5 6 E f 0 9 (Terminators) NDCA i- 1. 2 3 4 5 6 E + 0 9 (Terminators) NOHM + 1. 2 3 4 5 6 E + 0 9 (Terminators) NRAT f 1. 2 3 4 5 6 E f 0 9 (Terminators) NDIF + 1. 2 3 4 5 6 E f 0 9 (Terminators)

Figure 2-10. Binary Format

2-14

2. Default is (ASCII=@ or “T” equals 1 reading (i.e., Qa says that “T” equals 1 reading).

3. To empty the buffer, read “T” readings or reprogram (i.e., give an “X”).

4. Data storage buffer must be filled up to the programmed length (multiple of 10 up to 501 before any data is transmitted on the bus. Format is first in, first out. An “X” command clears the buffer.

5. In Ml, which is a Bus Response Mode, when the buffer is

full it will generate an SRQ (see SRQ Status Byte Format,

paragraph 2-29).

6. Cannot use buffer with T5 which is one of six Trigger modes. In the T5 Trigger mode each time an “X” is given,

the Model 619 will update the output data buffer and then clear it; therefore, it will never fill up. This will work with T4 Trigger mode since in this mode only one “X” is needed (see Table 2-12).

7. If the Model 619 is in a one-shot Trigger mode, there will

be no reading until the buffer is filled up. Therefore, it will take multiple triggers to fill the buffer.

Table 2-10. Data Terminators

except reserved letters

E.R.M.T.D.Q.Y.S.P.~.N.U.X

Pwr ONIDCLISDC Default Y ( LF) Note: <CR, =QD,

<LF> =OA,

Table 2-11. Data Storage Buffer Commands

1 Pwr ON/DCL/SDC 1 Default Q@

Table 2-12. Typical Trigger Time to First Byte Time

Change

Function

Range Channel

Integration ':y 1 ;;'

2.20 MEASUREMENT TIME

The time required to make a measurement is the sum of:

1. Control or command time to the Electrometer or measurement source.

2. The analog settling time. This is specified to 0.1% settling. All time constants are roughly first order.

3. The time from trigger to first byte available. A. This time is specified for various resolutions.

B. In addition, time must be added if the conversion is

the first on a new range or function, see Table 2-12

for conversion times.

4. Time to transmit data over the bus. A. In ASCII data format, 16 to 18 bytes are to ba

transmitted (4 in binary mode).

B. Time is determined mainly by the controller.

C. The Model 619 can transmit data as fast as 57~s per

byte. However, in the SO mode, a 6ms delay occurs

with each string.

D. If the controller waits more than 5.2msec before

obtaining the next byte, the Model 619 may delay

completion of the bus handshake by up to 3ms.

3 3

msec msec msec

msec

114 msec

2-15

2.21 READING RATE MODES (See Table Z-13) The Integration period is measured in milliseconds. Signal

zero and calibrate integration periods are equal. When one

of the measurement modes is triggered, the A/D will signal integrate, autozero and autocalibrate. The A/D will do a new autozero and autocalibrate if there is time to do them and another trigger is not given.

There are 6 Zero Correct registers (channel and function dependent)-ch A V, ch A A, ch AR, ch B V, ch B A, and ch B Q. After power up each register has a$ in it, To Zero Correct select the desired channel and function (lowest range) and perform the correction. After correction is done, the machine reverts back to the Zv mode (no need to program 20 after 21 -the Model 619 does it automatically.

i.25 BASELINE STORE

The 2 is autozero; C is autocalibrate: S is signal integrate. The trigger is indicated by a single quotation mark (‘1. The data is ready signified by double quotation marks (“I.

The delays are measured in milliseconds. The IEEE bus has approximately 5.2msec to take a reading once data is available. If the reading is not taken in this time, the retrig-

ger rate will be slowed down and will miss the reading in the continuous mode.

Integration periods for Sl, 52, and S3 are for 60Hz line operation. These are changed to 20msec integration periods for 50Hz. For measurement mode SS, 50/60Hz integration period is 4.lmsec. Switch 801.Sl on the Isolator board configures A/D timing appropriate for 50/60Hz.

Following a range change or channel changes, two additional integration periods are required for update of zero and calibration.

At sufficiently high trigger rates, autozero and autocalibrate

phases are bypassed. When a trigger is given the A/D will

do a signal integrate and then autozero and autocalibrate. If

the trigger is given before it can autozero and autocalibrate, it will do a signal integrate. Therefore, if trigger is given at a faster rate, autozero and autocalibrate will be bypassed.

In the Aameasurement modes, the front panel push-button switches will not respond. The LLO annunciator will turn on and the display goes blank except for the bus annunciators.

2.22 FILTER

1. P&The filter is disabled.

2. PI -The filter is enabled.

3. Pwr ON/DCL/SDC, default P!d.

2.23 ZERO CHECK Each channel has either Zero Check ON or OFF (not

tion dependent, just channel dependent).

1. C&The Model 619 is not in Zero Check.

2. Cl -The Model 619 is in Zero Check.

3. Pwr ON/DCL/SDC, default Cl.

2.24 ZERO CORRECT

1. Z&-Zero Correct table is not updated.

2. 21 -Update Zero Correct table.

3. Pwr ON/DCL/SDC, default 20.

1. N&Contents of baseline registers are not updated.

2. Nl- Baseline registers are updated, then it returns to N$ mode.

3. Pwr ON/DCL/SDC, default N$.

There are 6 Baseline Store registers (channel and function dependent 1~ ch A V, ch A A, ch A 0, ch B V and ch B RI. After power up, each register has a 0 in it. To store select the desired channel and function, and perform the storage. The value stored will be used as the correction to the

reading when Baseline Suppression is given.

2.26 BASELINE SUPPRESSION

1. U&The contents of any Baseline register will not be subtracted from the reading.

2. Ul -Subtract contents of appropriate Baseline register

from reading.

3. Pwr ON/DCL/SDC, default U@. NOTE

For Zero Check, Zero Correct, Baseline Store and Baseline Suppress, a trigger must be provided to complete these commands. For example if in “Tl” mode, giving ZlX will only set the Model 619 up to do a Zero Correct, The Model 619 will need to be addressed to talk (since in Tl) to complete the command.

2.27 DEFAULT CONDITIONS

When an SDC or DCL, Channels A and B will go to the following default conditions:

F@ - Volts R4 - 200V Range MB - Bus Response Mode (Standard) T0 Trigger Mode (Continuous on Talk) D@ Data Format (ASCII Data String) Y(LF)- Programmable Terminator (CR)(LF) S3 - Measurement Mode P,$ - Filter (Filter Out) Cl -Zero Check (In Zero Check) Z# Zero Correct (No update of Zero Correct table) Ng - Baseline Store (No update of contents in the Baseline

V!Zi - Baseline Suppression (Do not subtract contents of any

Baseline register from reading)

Channel A will be displayed.

2-16

Table 2-13. Reading Rate Modes

Continuous

rdglsec

(ASCII)

21.2

10.7

5.49

4.83

2.41

1.20

0.60

0.30

0.15

:onversion:

Averaged

1 2 4

1 2 4 8

ntegration Data1

kriod (a,dl :esolutior

4.1 3%

16.66 4%

16.66 4% 100 5% 100 5% 100 5% 100 5% 100 5% 100 5%

Thus resolution is always 5% digits.

*Must allow ZC time for analog specs.

**In mSec f250&x

***Available in front panel operation via Resolution pushbutton.

rrigger to First** Byte Delay k,e)

ECII

31.5

34.5 80

168 119

328

741 1680 3300 6700

164 IZ.C;*Z;C...T.;Z;S,C,S,Z,Y

112 z,c,*z,c...‘s” 323 Z,C,*Z,C,...S,Z,S” 736 Z,C,*Z,C...“S,Z,S,C,S,Z,S”

1680 z.c.*z.c...‘s.z.s.c.s.z.s”.s.. 3300 z;c;*z;c...s;z;s;c;s;z;s~~;s.. 6700 Z,C,*Z,C...‘S,Z,S,C,S,Z,S”,S..

Sequence

. ..s”cs”c... . ..s”cszs”c... . ..s”cszscszs”c.. . ..s”cszscszs”c.. . ..s”cszscszs”c.. . ..s”cszscszs”c..

.s”cszscszs”c.. . ..s”cszscszs”c.. ~..s”cszscszs”c..

On power up the Model 619 will default to the above conditions. In addition, the Zero Correct table and Baseline

registers are cleared. Also if the software Watch Dog detects a processing error the instrument is placed automatically in these default conditions.

2.28 TALK-ONLY MODE

The sequence of commands after the secondary address

and prior to execute is unimportant except that Baseline Store cannot be in the same line as function or channel change ISBS error (see SRQ status byte formats).

All commands are executed after “X” is given. Only commands that you wish to change need to be programmed.

The Model 619 may be used with a printer or other

nonintelligent devices through the IEEE Bus in Talk-Only mode. This particular mode is selected by SW7 on the

IEEE-488 module. (See the sketch regarding SW7). In the Talk-Only mode, ASCII data is sent continuously out to the interface. The front panel will default to these conditions

M@, Tfl, 00, Y(LF). All other device dependent commands

(function, range, reading rate, filter, etc.) are selected via the front panel pushbutton. Ratio and difference may be sent in Talk-Only mode, by not in Addressable mode. See

Figure 2-l. Address switch A6 is not used as a primary address switch.

NOTE

In Addressable mode, the following front panel push buttons are non-functional (Commands are locked out):

l RATIO (Only available in Talk-Only mode). l DIFFERENCE (Only available in Talk-Only mode).

Programming Example (Channel A, Using H.P. 9820 Desk

Top Computer Codes).

Let Model 619 primary address = 6 (Binary 00110).

? Unlisten A Talk Address of Controller 6 Primary Address of Model 619

Secondary Address of Channel A + !$ Continuous on Talk

Model 619 will not access SRO on error or data

F 1 Amps R 4 lOOnA Range S 3 6.25 Readings/Second

2.29 SRQ STATUS BYTE FORMAT

If an invalid command is given, no change in status will occur. If in the Ml response mode, service will be requested, and the error will be indicated in the SRQ byte. Extensive error checking is done during programming of the Model 619. The errors can be classified into two types; Pre”Execute” errors and Post”Execute” errors.

1. Examples of Pre”Execute” errors: A. VX = IddC

8. V2X = IddC C. ggX = IddC D. Fggg = IddC (must see and X to accept next com-

mand string)

E. F4X = IddCO

2. Examples of Post”Execute” errors: Do a ZO when not in Zero Check (CO).

3. Status Byte (see Figure 2-l 1).

4. Error Codes (D106= 1, error; see Table 2-14)

5. Data Codes (D106-0, nonerror; see Table 2-15)

2.30 MACHINE STATUS (Secondary Addresses c and d)

The Model 619 can be addressed to give its current machine status. To get the current status of Channel A, send (Talk Address) secondary address c. To get the current status of Channel B, send (Talk Address) secondary address d.

Figure 2-12 and Table 2-16 and 2-17 define each byte of information. QO must be in effect when reading machine status.

NOTE

If SRQ is not read within 1OOms after “SPE and Talk address,”

the Model 619 resets to

default conditions.

Filter Out (disabled)

0” ASCII Data String X Execute (This character terminates the command

string and causes their execution).

2-18

IMS BIT)

DlOS

0 l/O

D107

D106

l/O

Figure 2-12. Machine Status

Ill05

1 =ERROR CONDITION

O=NORMAL CONDITION

D104

110 l/O 110

D103

D102

(LS BIT)

DlOl

l/O

“Hex Code

3 4 5 6 7 8

*D104 through UWI

__^.

*D104 through DlOl

Table 2-14. Error Codas

Meaning

ILLEGAL DEVICE DEPENDENT Command

ILLEGAL DEVICE DEPENDENT Command Option Attempt to PROGRAM when not in remote No zerc check with 2 AMP No zero check with zero correct Spare No autoranging in this range Spare Invalid string with baseline store

NOTE

Data Codes 10106-O. nonerror) (see Table

2-16).

Table 2-16. Data Codes

‘Hex Code

1 2 4 5

Meaning

Normal OVERFLOW DIFFERENCE RATIO Buffer Full

Display

OFLO

Display

IddC IddCO no rn no 2AC Corr Il. noPu

ISbS

2-19

3yp2 0 Zero correct

:hA: 0 = Zero Correct off (20)

1 = Zero correct on (Zl)

Table~2-16. Byte Definitions

1 = Filter on (Pl)

:hB: Same as chA

%yte 2 Zero Check

:hA: 0 = Zero Check off (C0)

1 = Zero Check on (Cl)

:h 8: Sane as chA

lye 4 IRange

:hA: 0 = Autorange

1 = Range 1 (Rl) 2 = Range 2 (RZ) 3 = Range 3 (R3) 4 = Range 4 (R4)

= Range 5 (R5)

6 = Range 6 (R6)

7 = Range 7 (R7) 0 = Range 8 (RG) 9 = Range 9 (R9]

: = Range lO(R:)

chB: Same as chA

Byt_E 3 Function

chA: 0 = Volts (F0)

1 = Amps (Fl) 2 = Ohms (F2)

chB: Sam as chA

Rytc 5

chA: 0 = Non SRQ (M0)

chB:

Mode

1 =

SRO (Ml)

Same as chA

2-20

:hB:

lyte 6 Rate Type

:hA: 0 = Rate (SO)

:hB: Same as chA

Same as chA

1 =

Rate (Sl)

= Rate (S2)

= Rate (S3)

= Rate (54)

= Rate (S5)

6 = Rate (S6)

= Rate (S7)

= Rate (SR)

9 = Rate (S9)

Byte 7 Data

chA: 0 = ASCII (O0)

1 = Binary (Dl)

chR:

Same as chA

Byte 8

Triqger

I-

chA: 0 = Continuous on Talk (T0)

1 = One-Shot on Talk (Tl)

= Continuous an Get (TZ)

3 = One-Shot an Get (T3)

= Continuous on X (74)

= One-Shot on X (T5)

ch8: Same as chA

Byte

~~~

chA: 0 = Suppress off (UD)

Baseline Suppress

1 = suppress on (U0)

Table 2-16. Byte Definitions ICont.)

Dyte 9 Baseline Store

chA: 0 = No Store (N0)

chB: Same as chA

Byte

chA: 0 = Non-Autorangc

1 = Store Readinq (Nl)

Auto Ranqr

7 = nutoranqc

chl3 Same as chA

Byte 12 Int Period

chA: 4 = 16.66ms

5 = 4.1ms

8 = 20m

II = IflOms

chA: Same as chA chll: Same as chA

Byte 14

chA: 50/60HZ

0 = 60Hr

? = 5Ollr

chB: Ruffer State

1 = Ruffer no readings (00)

: = Buffer 10 readinqs (01)

= Ruffer 20 readings (42) ) = Buffer 30 readings (43) 8 = Buffer 40 readings (04)

= Buffer 50 readings (45)

chR:

Rytr 13 Terminator

ch A 7 = Y (OiL)

Eytc 15

chA: 0 = 1

chR: Same as chA

Sanr as chA

= = Y (CR)

: = Y (LF)

No. Readings to AVE,

I =2 2=4 3 = R 4 = 16 5 = 32

2-2112-22

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