Keithley 172 User manual

Models 172,173
Instruction Manual
Contains Operating and Servicing/Calibration
Information for Models 172,173,1722, and 1728
Publication Date: October, 1977
Keithley Instruments, Inc.
Instrument Division
Cleveland, Ohio, U.S.A.
Document Number: 28262

INSTRUCTION MANUAL
Dlgltat Multlmeter
Models 172,173
[Contalnr Operating and SafuWno/~bmtlon
In!omuNon For Moddr 172,173,1722, and 1728.1
‘1
KEITHLEY INSTRUMENTS m

INSTRUCTION MANUAL
Digital Multimeter
Models 172, 173
@COPYRIGHT 1976, KEITHLEY INSTRUMENTS, INC.
THIRD PRINTING, OCT. 1977, CLEVELAND, OHIO U.S.A.
DOCUMENT NO. 28262, REVISION CODE CC

INSTRUCTION MANUAL
Dlgltal hlultlmeler
Models 172,173
CONTENTS
I Section Page
CONTENTS
ILLUSTRATIONS.
......................... : : : : : : : : : : : : : : : : : : : : : : .. ii
iii
SPECIFICATIONS ............ "
I. GENERAL INFORMATION. ....... : : : : : : : : : : : : : : : : : : : : : : I-I
I
l-l. INTRODUCTION . . . . . . . . . . . . . . . . . . . .
l-2. FEATURES . . . . . . . . .
l-3.
QARRANTY INFORMATION . . . : : : : : : : : : : : : :
I
1-4. CHANGE NOTICE. . . . . . . . .
l-5.
OPTIONAL MODEL 1728 RECHARGEABL; ;A;T;R; PACK: : : :
l-6.
OPTIONAL MODEL 1722 DIGITAL INTERFACE. . . . . . . .
I
, 4.
I
I: 5.
I
i
I
OPERATING INSTRUCTIONS ...................
3-l.
GENERAL ........................
3-2. HOW TO SELECT POWER. .................
;I;. HOW TO SELECT FUNCTION
HOW TO SELECT RANGE. ................................ .
HOW TO MEASURE VOLTAGE ........
HOW TO MEASURE CURRENT (MODEL 172 ONLY): : : : : : : :
HOW TO MEASURE CURRENT (MODEL 173 ONLY).
HOW TO MEASURE RESISTANCE. .. .. ... : : : : : : :
FURTHER MEASUREMENT CONSIDERATIONS
;I?;. HOW TO USE MODEL 172/173 OFF-GROUND: : : : : : : : : :
3-11. HOW TO USE OPTIONAL PROBES AND SHUNTS. ........
3-12. HOW TO USE THE MODEL 1722 DIGITAL INTERFACE. .....
ACCESSORIES ....................
4-l. GENERAL..................:::: ::
POWER OPTIONS. ....................
ISOLATED DIGITAL OUTPUT. ........
4-4.
RACK MOUNTING. ............. : : : : : : :
4-5. PROBE AND SHUNTS ...................
4-6. CABLES AND CONNECTORS. ................
4-7. MISCELLANEOUS. ....................
THEORY OF OPERATION. ....................
5-l. GENERAL ........................
INPUT SIGNAL CONDITIONING. ..............
POWER SUPPLY, SCHEMATIC NO. 28067D ..........
DISPLAY BOARD PC-403 SCHEMATIC NO. 274780. ......
CURRENT BOARD, SCHEMATIC NO. 27478D. .........
MODEL 1728 RECHARGEABLE BATTERY PACK .........
ANALOG-TO-DIGITAL CONVERTER. .............
MODEL 1722 DIGITAL INTERFACE ....
5-9. DETAILED II-WIRE OHMS OPERATION ... : : : : : : : : :
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. . . . S-13
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ii AA

I INSTRUCTION MANUAL
Digllel Mulllmeter
Model8 172. 173
I CONTENTS (continued)
/section >_I Page
6.
MAINTENANCE. ................
6-1. GENERAL. ...............
6-2. : : : : : : : : : : : : : : : : : REQUIRED TEST EQUIPMENT. ........................
6-3. PERFORMANCE VERIFICATION
6-4. ADJUSTMENT/CALIBRATION PR&D;R; : : : : : : : : : : : : : : : : : : : :
6-5. TROUBLESHOOTING AND REPAIR , .
7. REPLACEABLE PARTS. . . . . . . . . . : : : : : : : : : : : : : : : : : : : : :
7-1.
GENERAL. . .
7-2. ORDERING INFORMATiON : : : : : : : : : : : : : : : : : : : : : : : : : :
J-3.
SCHEMATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ILLUSTRATIONS
-
n b
6-1
6-1
6-I
6-3
6-15 /
6-19,
J-1 1
;:; j
J-1 )
TitleFi ure No.g Page
I Dimensional Data. .......................... iv
: Tilt Bail Positions ......................... vi
Front Panel ............................. t-2
4
Bottom View Showing Line Cord .................... l-3
2 Rear Panel Showing Current Fuse and Check Points. .......... 2-2
Model 1728 Rechargeable Battery Pack. ................ 2-4
z Installation of Battery Pack. .................... 2-5
Front Panel Pushbutton Selection. .................. 3-3
9 Typical Model
172 Current Display .................. 3-5
IO Typical Model
I73 Current Display .................. 3-6
II Typical 2 WIRE Resistance Measurement ................
3-J
12 Typical 4 WIRE Resistance Measurement ................ 3-9
13
Semiconductor Diode and Transistor Testing. ............. 3-10
I4 Illustration of Floating Operation. ................. 3-11
I5 Model
1722 Digital Output Interface ................. 3-14
16 Installation of Model
1722. .....................
3-15
17
Connector Pin Identification. .................... 3-17
18 Card-Edge Connectors. ........................ 3-17
19 Location of Jumpers and Pull-Ups on Model
1722. ........... 3-18
20
Model 1010 Single Rack Mounting Kit. ..............
.4-Z
21 Model
1017 Dual Rack Mounting Kit. ............... : : .4-4
22
Overall Block Diagram of Model lJ2/173
............. : .
DC Volts Input Circuit
.5-l
23
.......................
.5-4
24
Simplified AC Attenuator Circuit ....... 1 : ‘.‘.‘: : : : : : :
.5-6
25
AC Converter Circuit ............ .
26
.5-6
Digital Display Multiplex Scheme .................. .5-II
27
Basic Functional Blocks of A/D Converter ..............
28
.5-14
...................
29
Basic Charge-Balance Converter .5-15
Operating Waveforms of A/D Converter ................ .5-16
30
Simplified Schematic of A/D Converter. ............... .5-18
;: Detailed Schematic of A/D Converter. ................ .5-20
A/D Converter System Timing. .................... .5-21
;:a. Model
1722 Block Diagram ...................... .5-24
Simplified Ohms Diagram (Shown in Z-WIRE Configuration). ...... .5-25
34b. Four-Wire Ohms Measuring Technique ................. .5-25

I
INSTRUCTION MANUAL
Digltal Multimeter
Models 172, 173
12.75
(324)
I
DIMENSIONS IN INCHES (MM)
FIGURE 1. Dimensional Data.
na

I
INSTRUCTION MANUAL
Digllal Multimeter
Model, 172, 173
SPECIFICATIONS
AA

INSTRUCTION MANUAL
Digital Mullimeler
Models 172.173
r
LEVEL POSITION - TILTBAIL AT FRONT
HANGING POSITIOI;
SHELF POSITION
45' POSITION LEVEL POSITION - TILTBAIL AT REAR
FIGURE 2. Tilt Bail Positions.
vi
AA

INSTRUCTION MANUAL
Digital Multimeter
Models 172. 173
GENERAL INFORMATION
I
SECTION I. GENERAL INFORMATION
l-l. INTRODUCTION. The Models 172 and 173 Digital Multimeters are wide-range, general-
purpose measuring instruments, capable of measuring ac/dc voltage, ac/dc current, and
resistance.
l-2. FEATURES
a. Automatic Ranging and Polarity
b. Manual Range Selection and Range Hold
C. HI and LO Otxns Capability
d. Line Operation
e. Optional Battery Operation, Model 1728.
f. Floating Capability to ?lbOOV peak
9. Optional Isolated Digital Interface, Model
1722
l-3.
WARRANTY INFORMATION. The warranty is stated on the inside front cover of the
manual. If there is a need for service, contact your Keithley representative or author-
ized repair facility as given in OUT catalog.
l-4. CHANGE NOTICE. Improvements or changes to the instrument not incorporated into the
manual will be explained on a change notice sheet attached to the inside back cover of
the manual.
l-5. OPTIONAL MODEL
1728 RECHARGEABLE BATTERY PACK. The Model 1728 is an accessory
batterY pack which enables either line or battery operation. The Model 1728 has built-
in recharging circuitry. The Model 1728 is field-installed on the Model 172/173 chasis.
l-6. OPTIONAL MODEL 1722 DIGITAL INTERFACE. The model 1722 is a field-installable
~~~~digital output option. It provides isolated open-collector BCD outputs and control lines.
The A
IMPORTANT
symbol can be found in various places in this Instruction Manual. Carefully
read the associated CAUTION statements with regard to proper use and handling of the
instrument. Damage to the instrument may occur if these precautions are ignored.
The t symbol can be found in various places in this Instruction Manual. This symbol
indicates those areas on the instrument which are potential shock hazards. Carefully
read the associated WARNING statements with regard to proper use and handling of the
instrument. Serious personal injury may result if these precautions are ignored.
~
cc
l-l

GENERAL INFORMATION INSTRUCTION MANUAL
Digital Multimeter
Models 172.173
FUNCTION AND UNITS DISPLAY (my)
INPUT HI AND LO, UPPER PAlR
(OHMS SOURCE. LOWER PAIR)
\\
VOLTAGE FUNCTION (OUT)
AHPERES FUNCTION (IN)
DC FUNCTION
AUTORANG, NG (OUT)
MANUAL RANGING (IN)
LINE POWER
(LINE AND EAT MUST BE OUT FOR BATTERY CHARGE)
FIGURE 3. Model 173 Front Panel
I
l-2 CC