Keithley 1792, 6422 Instruction Manual

INSTRUCTION MAdUAL

Models 1792,6422
Isolated BCD Outputs

Keithley instruments, Inc.
28775 Aurora Road/Cleveland, Ohio 44139/(216) 248-0400

WARRANTY

Keithley Instruments, inc. warrants this product to be free from defects
in material and workmanship for a period of 1 year from date of ship­ment. During the warranty period, we will, at our option, either repair
or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley represent­ative, or contact Keithley headquarters in Cleveland, Ohio. You will be

given prompt assistance and return instructions. Send the instrument,
transportation prepaid, to the indicated service facility. Repairs will be
made and the instrument returned, transportation prepaid. Repaired
products are warranted for the balance of the original warranty period,
or at least 90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from unauthorized

modification or misuse of any product or part. This warranty also does

not apply to fuses, batteries, or damage from battery leakage.

This warranty is in lieu of all other warranties, expressed or implied, in-

cluding any implied warranty of merchantability or fitness for a par­ticular use. Keithley Instruments, Inc. shall not be liable for any indirect,
special or consequential damages.

STATEMENT OF CALIBRATION

This instrument has been inspected and tested in accordance with
specifications published by Keithley Instruments, Inc.

The accuracy and calibration of this instrument are traceable to the

National Bureau of Standards through equipment which is calibrated at

planned intervals by comparison to certified standards maintained in
the Laboratories of Keithley Instruments, Inc.

KEITHLEY INSTRUMENTS, INC.
INSTRUMENT DIVISION / 28775 Aurora Road / Cleveland, Ohio 44139 / U.S.A. / [phone] / Telex: 98-5469

WEST GERMANY: Keithley Instruments GmbH / Heiglhofstr. 5 / 8000 Munchen 70 / [phone] / Telex: 52-l 2160
GREAT BRITAIN: Keithley Instruments, Ltd. I 1, Boulton Road I Reading, Berkshire RG 2 ONL / [phone]/88 /Telex: 84-7047
FRANCE: Keithley Instruments SARL / 2, Bis Rue Leon Blum / B.P. 60 / 91121 Palaiseau Cedex / (6) 011-51-55 I Telex: 600-933
NETHERLANDS: Keithley Instruments BV / Arkelsedijk 4 / Postbus 559 / 4200 AN Gorinchem I (0) 1830-25577 / Telex: 24-684
SWITZERLAND: Keithley Instruments SA I Kriesbachstr. 4 / 8600 Dubendorf I 01/821-94-44 / Telex: 57-536
AUSTRIA: Keithley Instruments Ges.m.b.H. / Doblinger Haupstr. 32 / 1190 Wien / 314 289 / Telex: 13-4500

MODELS 1792, 6422

I SOLATED BCD OUTPUTS

Copyright 1979, Keithley Instruments, Inc.

Third Printing, May 1981, Cleveland, Ohio

U.S.A.

Document No. 30155, Rev. B

TABLE OF CONTENTS

SECTION TITLE

PAGE

1.

GENERAL INFORMATION ................... l-l

l-l.

INTRODUCTION ...................... l-l

l-3. COHPATIBILITY. ..................... l-l

l-5. WARRANTY INFORMATION .................. l-l

l-7. CHANGE NOTICES ..................... l-l

l-9.

SAFETY SYMBOLS ..................... l-l

l-11. SPECIFICATIONS ..................... l-l

2. INITAL PREPARATION ...................... 2-l

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

2-3.

UNPACKING AND INSPECTION ................ 2-l

2.5.

PREPARATION FOR USE. .................. 2-l

2-7. MODEL 1792 INSTALLATION. ................ 2-3

2-9. Fidel 1792 Output Connections. ............ 2-3

2-11. IIODEL 6422 INSTALLATION. ................

2-4

3.

GPERATION ....................... .3-l

3-l.

INTRODUCTION ...................... 3-l

3-3.

OVERALL OPERATION. ...................

3-l

3-9. CIRCUIT DESCRIPTION. .................. 3-3

3-11.

Control Circuitry. ..................

3-3
3-14

Switching Circuitry. ................. 3-4

3-16.

Isolator Network ................... 3-4

3-18.

Busy/Hold Circuit. .................. 3-4

3-20.

Output Registers And Buffers ............. 3-5

3-22. DC-to-DC Converter .................. 3-5

3-24 TEST POINT DATA. .................... 3-5

3-26.

SPECIAL HANDLING OF STATIC SENSITIVE DEVICES ......

3-6

4.

REPLACEMENTPARTS ...................

4-l

4-l. GENERAL. ........................ 4-l

4-3.

ORDERING INFORMATION ..................

4-l
4-5.

SCHEMATIC. ....................... 4-l

4-7.

COM’ONENT LAYOUT ....................

4-l

I LLUSTRATI GNS

FIGURE

TITLE PAGE

2-l

Installation of Model 1792 ............... 2-2

2-2

Installation of Model 6422 ............... 2-5

3-1

Model 1792/6422 Block Diagram. ............... 3-l

3-2

Timing Diagram ..................... 3-2

3-3

Ring Counter and Gating. ................ 3-3

3-4

Busy/Hold Circuit. ................... 3-4

UODELS 1792, 6422

SECTION 1 GENERAL lNFGRMATI(%

GENERAL INFORMATION

l-l. I NTRODUCT I ON.

l-2.

The Models 1792 and 6422 are isolated BCD
output options that convert displayed meter readings
to electrically isolated, latched, and buffered per­al lel 8CD outputs.

These can be appl ied to I ine

printers or other external data hand1 ing equipment.

Logic

levels are TTL/DTL and CMOS compatible.
Output data includes sign and overrange signals. In
addition,

a BUSY control I i ne indicates that the

meter is updating data.

The trailing edge of this

signal is normally used to initiate a print or load

operation at the listening device. An input control

I ine (HOLD) al lows the listening device to inhibit
the update of output data. When this line is high,
the data update rate is the same as the meter

conversion rate,

typically 2.5 readings/second.

Operating characteristics for the Models

6422 and

1792 are given in their respective Specification

Tables (Table l-l and l-2).

Both options can be

either factory or field installed.

Separate

installation procedures are provided in this manual,

because of the different mounting and output cabling

provisions of the options.

l-3. CGf+‘ATIBILITY.

l-4.

The Model s 1792 and 6422 interface options

are

compatible with the following Keithley

I nstr unents:

Model 6422

Model 642 Electrometer Serial Nunber 53402A and
above.

Mode I 1792

Model 179 DMFl Serial Nunber 20000 and above.
Model 179-20A DMFl all Serial Numbers.
Model 177 DMM Serial Nunber 14500 and above.
Model 480 Picoammeter Serial Nunber 12000 and
above. Note:

First 3-l/2 digits at BCD auf-put

same as Model 480 display.

l-5.

WARRANlY INFGRMATIOIJ.

l-6.

The Warranty 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.

l-7.

CHANGE NOTICES.

l-8.

Improvements or changes to the equipment which
occur after printing of the Instruction Manual will
be explained on a Change Notice sheet attached to

the inside back cover.

l-9. SAFETY SYMOBCLS

l-10.

Safety symobls used in thls manual are as

fol lows:

IM3oRTANT

The ! n symbol can be found in various places in
this manual. Careful ly read the associated CAU­TION statements with regard to proper use and

handling of the equipment. Damage to the equip-

ment may occur if these precautions are ignored.

t

This

symbol can be found In various places in

this manual.

This symbol indicates those areas on
the equipment which are potential shock hazards.
Careful ly read the associated WARNING statements

with regard to proper use and hand1 Ing of the

equipment.

Serious personal injury may result if

these precautions are ignored.

1-11. SPECIFICATIONS.

l-12.

Detailed specifications for the Model 1792

and 6422 are given

In Tables l-l and 1-2,

respectively.

l-l

GENERAL INFORMATION

MODELS 1792, 6422

SPECIFICATIONS

TABLE I-1

SPECIFICATIONS, MODEL 1792 ISOLATED BCD OUTPUT

OUTPUTS : 4-l/2 digit parallel BCD, polarity,

overrange bit, busy.

BUSY:

Low during output update (5Oms max).

OUTPUT UPDATE RATE:

Same as meter conversion rate

(2.5 reading/second typical).

CONTROL : E inhibits subsequent output updates

when low.

LOGIC LEVELS: TTL/DTL and CMOS compatible.

Output High = 4.5V minimum while

sourcing lOOkA.

Low =

0.5V maximum while
sinking 3.2mA.

Control High = open or 4V minimum.

Low =

.5V maximum while

sinking 1mA.

ISOLATION:

All outputs and controls isolated from
meter up to 1400V peak, 105V*Hz.

(lOlO, ,ll40pf typ1

ENVIRONMENT: Operate 0 to 55”C, 0 to 805 RH.

Storage’ -25 to 7O’C.

OUTPUT CONNECTOR:

26 pin card edge, mates with

CS294-1 (3M 3462 or equivalent)

INSTALLATION: Field installable, mounts within

and powered from Keithley meter.
Adds 0.2kg (0.51 bs).
Precludes Mode I 1788 battery pack

installation.

ASSESSORIES AVAILABLE: Model 1796 - 10’ ou-t-

put mating cable, one end unter-

minated.

Model 1797 - 10’ intercon-

nect cable to 750/7502 printer.

TABLE l-2

SPECIFICATIONS, MODEL 6422 ISOLATED BCD OUTPUT

OUTPUT:

4-l/2 digit parallel BCD, polarity,
overrange bit, busy.

BUSY: Low during output update (50111s max).

OUTPUT UPDATE RATE:

Same as meter conversion
rate (2.5 reading/second
typical).

CONTROL : HOLD inhibits subsequent output updates

when low.

LOGIC LEVELS:

TTL/DTL and CF%X compatible.
Output High = 4.5V minimum while

sourcing lOOpA.

Low = 0.5 maxlmum while

sinking 1 mA

Control High = open or 4V minimum.

Low = .5V maximum while

sinking 3.2mA

I SOLAT I ON :

All outputs and controls isolated from
meter up to 30V peak, 105VoHz.

(lolon II ,4OPf tYP)

ENVIRONMENT:

Operate 20°C to 30°C
Storage -25°C to +55’C.

OUTPUT CONNECTOR: 26 pin ribbon cable, unterminated.

INSTALLATION:

Field installable, mounts within and
powered from Keithley meter. Adds 0.4kg (1.0 Lbs).
Precludes Model 6428 battery adapter

installation.

l-2

MODELS 1792. 6422

SECTION 2. INITIAL PREPARATION.

INITIAL PREPARATION

2-l. INTRCOUCTION.

2-2.

This section provides information for r(ncomlng
inspection and preparation for use of your Model
1792/6422 BCD output option.

2-3.

UNPACKING AND INSPECTION.

2-4. The Model 1792/6422 was careful ly inspected,

both mechanically and electrically before ship-

ment.

Upon receiving your BCD output option, un­pack all items from the Sh i ppingcontainer and
check for any obvious damage which may have oc­cured during transit.

Report any damages to the
shipping agent. Retain and use the original
packaging materials if reshipment is required.
The following items (Keithley Part No. in paren­theses) are shipped with al I orders of your
option:

Model 1792

a - PC-498 and shield Assembly

1) PC-488 Assembly (29961D)

2) Shield Assembly (30108C)

b.

-

Replacement Top Cover (30136C)

c. A copy of this Instruction Manual (30155)

­d. - Separate Optional Cable (Model 1796 or

1797), as ordered.

Model 6422

a. Assembled PC Board (299610) with modif ied PC-

­498 (301658).

b.

Shield (301328).

-

5 Output Cable assembly with back panel and

strain rel iefs.

I) Cable assembly (302348-l)

2) Back panel (301318).

3) Two strain reliefs (27686A).

-. Mounting Hardware

d

I) Eight Standoffs (ST-94).

2) Eight 6-32 X 5/16” screws.

8. - A copy of this Instruction Manual (30155).

2-5. PREPARATION FOR USE.

2-6. The

Models 1792 and 6422

are

shipped ready

for installation.

Separate installation procedures

are provided.

Install the Model 1792/6422 in your

instrument using

the

appl icable

installation

procedure.

TABLE 2-l

MODEL 1792/6422 Output Connections

1792/6422

P40 1 cs-294- 1 CABLE*

FUNCTION

PIN NO.

PIN NO

WI RE NO. b COLOR

Common

1 1 1 BRN

Common

2 2 2 RED

HOLD ( Input)

3 3 3 ORN

BUSY

4 4 4 YEL

Dl-B (2)

5 5 5 GRN

Dl-A (1)

6 6 6 BLUE

Dl-0 (8)

7 7 7 VI0

01-C (4)

8 8 8 GRAY

02-B (2)

9 9 9 WHT

02-A (1)

10 10 10 BLK

02-D (8)

11 11 11 BRN

02-C (4)

12 12 12 RED

03-B (2)

13 13 13 ORN

’

D3-A (1)

14 14 14 YEL

D3-D (8)

15 15 15 GRN

D3-C (4)

16 16 16 BLUE

04-B (2)

17 17 17 VI0

04-A (1)

18 18 18 GRAY

04-D (8)

19 19 19 WHT

D4-C (4)

20 20 20 BLK

Common

21 21 21 BRN

05

22 22 22 RED

Overrange

23 23 23 ORN

Sign

24 24 24 YEL

Common

25 25 25 GRN

Common

26 26 26 BLUE

*Part of 6422 cable assembly or optional Model 1796
cable assembly.

2-l

\NITIAL PREPARATION

MODELS 1792, 6422

CARD-EDGE .
CONNECTOR

PIN 2 (TOP)

PIN 1 (UNDERNEATH)

,-Model 1792

I I

-

;+ \P1?08

PL

\GROUNF CLIP :

1

ASTIC SPACER

(4 PLACES)

1792-0023-A

FIGURE 2-l.

Installation of Model 1792.

2-2