Keithley 193A User manual

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Instruction Manual
Model 193A
System DMM
01985, Keithley Instruments, Inc.
Instrument Division
Cleveland, Ohio, U.S.A.
Document Number 193A-901-01

SAFETY PRECAUTIONS
The following safety precautions should be observed before operating the Model ~193A
This instrument is intended for use by qualified personnel who recognize shock huxds .~nd are i,lmiliar
with the safety precautions required to avoid possible injury. Read WET the manual carefully before operating
this instrument.
Exercise extreme caution when a shock hazard is present at the instrument’s input. The American National
Standards Institute (ANSI) states that a shock hazards exists when voltage levels greater than 3OV rms or
42.4V peak are present. A good safety practice is to expect that a hazardous voltage is present in any unknown
circuit before measuring.
Ins
.R ect the test leads for possible wear, cracks or breaks before each use. If any defects are found, replxe
wt test leads that have the same measure of safety as those supplied with the instrument.
For optimum safety do not touch the test leads or the instrument while power is applied to the circuit under
test. Turn the power off and discharge all capacitors, before connecting or disconnecting the instrunwnt.
Always disconnect all unused test leads from the instrument.
Do not touch any object which could provide a current path to the common side of the circuit under lest
or power line (earth) ground. Always make measurements with dry hands while standing on ‘1 dry, ill-
s&ted surface, capable of withstanding the voltage being measured.
Exercise extreme safety when testing high energy power circuits (AC line or mains, etc). Refer to the t ligh
Energy Circuit Safety Precautions found in paragraph 2.6 (Basic Measurements).
Do not exceed the instrument’s maximum allowable input as defined in the specifications and operation
section.

SPECIFICATIONS
DC VOLTS
ACCURACY (5% Digits)” TEMPERATURE
MAXIMUM * t%rdg +
counts)
COEFFICIENT
READING RESOLUTION INPUT 24
Hr., 90 Days, 1 Yr., ANALOG 1
it%rdg+countsli~~ C SETTLING ~
RANGE (5% Digits) 6% 5% RESISTANCE 23O+l”C 23’*5T 23’f5”C O”-18’C & 28--5O~C TIME”* i
200mV 219.999mV 10” n” 1 IrV >lCX 0.003+2* 0.005+2’ 0.00x+2* o.wK? in1 < zms
2 V 2.19999 V 1 $V lop” >lCx 0.002+
1 0.005+2 0.007+2
(l.WOS+~0.I < 1,115
20 V 21.9999 V 10 &V 100 &V 1OMCl 0.003+
1 0.007+1 0.009+3 (1.lx)O7+O.l
< I”,>
200 V 219.999 V 100 ,,V lm” 1OMR 0.003+1 O.O07+l 0.009+3 O.WO7
+o.I < lms
1000 v 1000.00v 1mV 1OmV 1OMR 0.004+1 0.007+1 0.009+5 0.0007+0.1
< I”,5
*When properly zeroed. **Multiply digit error by 10 for h%~digit accuracy. “‘To (1.01% of step ch.qe.
NMRR: Greater than 60dB at 50 or 60Hr. MAXIMUM MEASUREMENT RATES (into internal
CMRR: Greater than 120dB at dc and 50 or 6OHz
memory, filter and multiplex off):
(with lk0 in either lead). 3% Digit 4% Digit 5% Digit 6’12Digit
MAXIMUM ALLOWABLE INPUT: 1OOOVpeak. 1000 rdgis 333 rdgls 25 rdg:s 25
rdg s
TRMS AC VOLTS (Option 1930)
MAXIMUM
ACCURACY (5% Digits)‘*’
READING
RESOLUTION + t%rdg + counts, 1 Year, 18’.28 c
RANGE
(5% Digits) 6% 5%
20Hz-50Hz’
50Hz-IOkHz’ IOkHz-20kHz’ ZOkHz-100kHz”
2" 2.19999"
1Ir” 10pv
1+ 100
0.25+ I(10 11.35+300 I f so0
2ov 21.9999" 10/Lv 100 flv 1+ 100 0.25+100 L1.35
+SW I f xx1
2oov 219.999" 100PV 1mV 1+ 100 0.25+ 100 13.31+3Nl
I _3ki
700" 700.00 v
1mV lOmV 1+100 0.35+100 0.5 4~SW I + SiHl
*Above 2000 COUPES.**Above 20000 counts; 3%+500 typical below 20000. “‘Multiply digit erwr by ill for 6’.:-digit .~cur.xy. ~
RESPONSE: True root mean square, ac or ac+dc. 3dB BANDWIDTH:
500kHr typical. !
CREST FACTOR: Rated accuracy to 3. Specified for
CMRR: Greater than 6OdB at 50 and 6OHr (Ikl2 1111. ~
pulse widths > lops, peak voltage 5 1.36 x full scale. balance).
AC+DC: Add 60 counts to specified accuracy. dBV (Ref. = 1V):
ACCURACY +dBV
MAXIMUM INPUT: 1OOOVpeak ac+ dc, 2x lO’V*Hr. 1 Year. In~-zn c
SETTLING TIME: 0.5s to within 0.1% of change in INPUT ZOHz-ZOkHz ZOkHz-1WkHr RESOLUTION
reading. 14to +57dHV
INPUT IMPEDANCE: 1Mfi shunted by less than 120pF.
(2OOmVt* 7WV rms) 0.2 11.4 ,JOldH\’
TEMPERATURE COEFFICIENT CO’=-18°C& 28’-50°C): -34 to 14dUV
Less than *(0.1x applicable accuracy specification)i”C
(20mV t0 2OOmV) I.s S’ i)~illdH\
below 50kH.z; (0.2x) for 50kHz to 100kHr.
‘Typical
200mv
100 pv 2+3
2" ImV 2+3
20 v
1OmV 2+3
200 v 100mV 2+3
700 v 1 v
2+3

OHMS
ACCURACY (5% Digits)***
MAXIMUM CURRENT -t (%rdg + counts)
READING RESOLUTION THROUGH 24
Hr., 90 Days, 1 Yr.,
RANGE (5% Digits) 6% 5’,2
UNKNOWN
230 * 1°C 23’ i ST 230 i5T
200 n 219.999 n 100 po lmfl ImA 0.0035+2* 0.007+2* 0.010+2*
2 kO 2.19999 k!I ImIl 1Omfl ImA 0.0035+2 0.007+2 0.010+2
20 kn 21.YYYY k0 Nllll~ 1oomn 100 &A 0.0035+2 0.007+2 0.010+2
200 kR 219.999 kll 1OOmR 1 n 10 I”A 0.0035+2 0.007+2 0.010+2
2Mfl 2:19999Mn 1 R ‘IO n 14 0.005 +2 0.010+2 Ll.o10+2
20Mll 21.9999MQ 10 n 100 a 100 nA 0.040 +2 0.070+2 0.070~2
200Mn 21Y.YY9Mn 100 R 1 kn 100 nA** 3.2 +2 3.2 +2 3.2 +2
*When properly zeroed. **Nominal short circuit current.
***4-terminal accuracy 200S20k range. Multiply digit error by 10 for 6’/zd accuracy.
TEMPERATURE
COEFFICIENT
*(%rdg+counts)/“C
O”lBoC & 28’-5O’C
0.001+0.7
0.001+ 0.1
0.001+0.1
0.001+0.1
0.001+0:1
0.010+0:1
0.230+0.1
CONFIGURATION: Automatic 2. or 4.terminal.
MAXIMUM ALLOWABLE INPUT: 350V peak or
250V rms.
MAXIMUM OPEN CIRCUIT VOLTAGE: 7V
DC AMPS (Option 1931)
ACCURACY
(5% Digits) (S/2 v,ges, 1 TEMPERATURE
RESO-RESO- (1 Year)(1 Year) COEFFICIENT
LUTION *(%rdg+counts)*(
LUTION *(%rdg+counts) -t(%rdg+counts)i”C
RANGE 15% Dieits)
RANGE (5% Digits) 18*28”C 18*28”C 0’ 00-18T & 280-SOT
200 pA InA 0.09+10 0.01+0.5
OVERLOAD PROTECTION: 2A fuse (25OV), externally
accessible.
MAXIMUM VOLTAGE BURDEN: 0.25V on 200pV
through 20mA ranges; 0.28V on 200mA range; 1V on
2A range.
2mA 10nA 0.09+10 0.01+0.5
20mA lOOnA 0.091-10 0.01+0.5
200mA l@A 0.09+10 0.01+0.5
2 A lo+4 o.o9+1O 0.01+0.5
TRMS AC AMPS (Options 1930 and 1931)
ACCURACY*
45Hz to 1OkHz
(5% Digits) TEMPERATURE
RESO- (1 Year) COEFFICIENT
LUTION +(%rdg+counts) -t(%rdg+counts)/“C
RANGE (5% Digits) 180-28°C 0”-18”C & 28%5O’C
GO fill ‘InA 0.6+300 0.04+10
2mA 1OnA 0.6+300 0.04+10
20mA IOOnA 0.6+300 0.04+10
200mA ‘IpA 0.6+300 0.04+10
2 A 10fiA 0.6+300 0.04+10
*Abwc 2000 counts.
RESPONSE: True root mean square, ac or ac+dc.
CREST FACTOR: Rated accuracy to 3. Specified for
pulse width > lms, peak current 5 1.36 x full scale.
MAXIMUM VOLTAGE BURDEN: 0.25V on 2OOpV
through 20mA ranges; 0.28V on 200mA range; 1V on
2A range.
OVERLOAD PROTECTION: 2A fuse (25OV), externally
accessible.
SETTLING TIME: 0.5s to within 0.1% of change in
reading.
dB (Ref. = ImA):
ACCURACY + dB
1 Year, 18O-28°C
INPUT
45Hz-10kHz
RESOLUTION
-34 to +66dB
20pA to 2A
-54 to -34dB
2pA t” 20/~/I
0.3 O.O~ldB
2 O.OldU

TEMPERATURE (Thermocouple) (over IEEE Blrs only)
THERMO- ACCURACY=
COUPLE (1 Year)
TYPE RANGE RESOLUTION 113°-28”C
J
-100 to + 760°C O.l”C 10.5”C
K -100 t” +1372”C O.l”C +0.5”C
T -100 to + 400°C O.l”C +0.5oc
E - 100 to + 1000°C O.l”C kO.h”C
R 0 to +1768”C 1 “C *3 “C
s 0 to c176PC 1 “C *3 “C
B
c350 t” +1821”C 1 “C 1-5 “C
‘Relative to external 0°C reference junction; exclusive of ther-
mocouple errors. Junction temperature may be external.
TEMPERATURE (RTD)
4-WIRE
RESO- ACCURACY* TEMPERATURE
RANGE LUTION 1 Yr., 18°-2~oC
COEFFICIENT
1000 to O.Ol"C *o.lt?"c
* (0.0013% +
+63O”C O.O05~C)/~C
148O to O.Ol”F 10.36OF *(0.0013%+
+llOO”F 0.01 ‘F)PC
*Excluding probe errors.
RTD TYPE: 1000 platinum; DIN 43 760 or IPTS-68, alpha
0.00385 or 0.00392, 4.wire.
MAXIMUM LEAD RESISTANCE (each lead): 4.wire,
10R.
SENSOR CURRENT: 1mA
COMMON MODE REJECTION: Less than 0.005”CIV at
dc, 50Hz and 60Hz (lOOn unbalance, LO driven).
MAXIMUM ALLOWABLE INPUT: 350V peak, 250V
*Ins.
IEEE-488 BUS IMPLEMENTATION
Multiline Commands: DCL, LLO, SDC, GET, GTL,
UNT, UNL, SI’E, SI’D.
Uniline Commands: IFC, REN, EOI, SRQ, ATN.
Interface Functions: SHl, AHl, TEO, LA, LEO, SRl, RLZ,
PPO, DCl, DTl, CO, El.
I’rogrammable Parameters: Range, Function, Zero, Inte-
gration Period, Filter, dB Reference, EOI, Trigger, Ter-
minator, Delay, 500-rd P Storage, Scaling, Calibration,
Display, Multiplex Of, Status, Service Request, Self
Test, Output Format.
GENERAL
DISPLAY: 14, 0.5.in. alphanumeric LED digits \vith
decimal point and polarity. Function and IEEE bus
status also displayed.
RANGING: Manual or fast autoranging.
ISOLATION: Input LO to IEEE LO or power line
ground: 500V max., 5xlOSV.Hz; greater than ~10%
paralleled by 400pF.
DATA MEMORY: I to 500 locations, progrumwble,
Measurement intervals selectablr lms to 999.999x-c or
triggered.
BENCH READING RATE: 5 readingswr, vwpt 2O~lIl;
ZOOMR range 2 rcadingsisec.
ZERO: Control subtracts on-scale value from subsequent
readings or allows value to bc programmed.
FILTER: Weighted average (exponential). Programmable
weighting: 1 to &
WARMUP: 1 hour to rated accuracy.
OPERATING ENVIRONMENT: [I’,-50 C’, 0% to 809,
relative humidity up to 35’C; linearly derate 3%
RH/“C, 35°C to 50°C (except 2OOMII range: 0% TV,M1”,>
RH up to 28°C).
STORAGE ENVIRONMENT: -25~~ to +65-C.
POWER: 105.725V or 210.250V (internal switch selected),
50Hz or 6OHz, 40VA maximum 90.I~ItlV & 180.22O\’
versions available upon request.
CONNECTORS: Analog: Switch selectable front (lr rear,
safety input jacks. Digital: TRIGGER input and \‘(>I-.I-
METER COMPLETE output on rear panel, BSCs.
DIMENSIONS, WEIGHT: 89mm high x 43Hmm wide
x 441mm deep (3% in. x ~17%in. x 171%in.). Set
weight 33kg (15 Ibs.).
ACCESSORlES AVAILABLE:
Model 1600A: Hi h Voltage Probe
Model 1641: K&n Test Lead Set
Model 1651: 50.Ampere Shunt
Model 1681: Clip-On Test Lead Set
Model 1682A: RF Probe
Model 1685: Clamp-On Current Probe
Model 1751: General Purpose Test Leads
Model 1754: Universal Test Lead Kit
Model 1930: True RMS ACV Option
Model 1931: Current Option
Model 1938: Fixed Rack Mounting Kit
Model 1939: Slide Rack Mounting Kit
Model 7007-l: Shielded IEEE-488 Cable, lm
Model 7007-2: Shielded IEEE-488 Cable, 2m
Model 7008.3: IEEE-488 Cable, 3 ft. (0.9m)
Model 7008.6: IEEE-488 Cable, 6 ft. (1.8m)
Specifications subject to change without notice,

TABLE OF CONTENTS
SECTION l-GENERAL INFORMATION
1.1 INTRODUCTION ............................................................................ 1-l
1.2 FEATURES .................................................................................. 1-l
1.3 WARRANTY INFORMATION ................................................................. I-1
1.4 MANUAL ADDENDA ....................................................................... l-l
1.5 SAFETY SYMBOLS AND TERMS ............................................................. l-1
1.6 SPECIFICATIONS ........................................................................... 1-2
1.7 INSPECTION ............................................................................... l-2
1.8 USING THE MODEL 193A MANUAL, ........................................................ l-2
1.9 GETTING STARTED ......................................................................... 1-2
1.10 ACCESSORIES .............................................................................. 1-3
SECTION 2-BASIC DMM OPERATIONS
2.1
2.2
22.1
2.2.2
2.2.3
2.2.4
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.4
2.4.1
2.4.2
2.4.3
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
2.6.7
2.6.8
2.6.9
2.6.10
2.6.11
2.6.12
2.6.13
2.7
2.7.1
2.7.2
2.8
2.8.1
2.82
INTRODUCTION ........................................................................... 2-l
POWER UPPROCEDURES ................................................................... 2-l
Line Power ................................................................................ 2-l
rower-up Sequence ........................................................................ 2-I
Factory Default Conditions ................................................................. 2-I
User Programmed Conditions .............................................................. 2.2
FRONT PANEL FAMILIARIZATION .......................................................... 2-2
DisplayandIndicators ..................................................................... 2-2
Controls.. ................................................................................ 2.2
Input Terminals ........................................................................... 2-4
Current Fuse .............................................................................. 2-4
REAR PANEL FAMILIARIZATION ............................................................ 2-3
Connectors and Terminals .................................................................. 2-4
Calibration Switch ......................................................................... 2-5
Line Fuse ................................................................................. 2-S
ERROR AND WARNING DISPLAY MESSAGES ............................................... 2-5
BASICMEASUREMENTS .................................................................... 2-Y
Warm Up Period .......................................................................... 2-Y
Zero ...................................................................................... 2-Y
Filter ..................................................................................... 2-11
DC Voltage Measurements ................................................................. 2-12
Low-Level Measurement Considerations., ................................................... Z-13
TRMS AC Voltage Measurements. .......................................................... 2.14
Resistance Measurements .................................................................. 2-15
Current Measurements (DC or TRMS AC) ..................................................
2-16
RTD Temperature Measurements ........................................................... 2.17
dBMeasurements ......................................................................... 2.17
dB Measurement Considerations and Applications,, ......................................... 2-19
TRMS AC + DC Measurements ............................................................ 2-19
TRMS Conslderatmns
....................................................................... Z-20
DATA STORE .............................................................................. 2-22
Storing Data ............................................................................. 2-22
Recalling Data ............................................................................ 2-23
FRONT PANEL PROGRAMS ................................................................ 2.25
Cursor and Data Entry, ................................................................... 2-25
ProgramTEMP ........................................................................... 2-25
i

2.8.3
2.8.4
2.8.5
2.8.6
2.8.7
2.8.8
2.8.9
2.8.10
2.8.11
2.8.12
2.8.13
2.8.14
2.8.15
2.9
2.10
2.10.1
2.10.2
2.10.3
Program AC + DC (Low Frequency AC).
Program dB ...........................
Program ZERO ........................
Program FILTER .......................
Program RESET .......................
Program4 ............................
Program 90 (Save) .....................
Program 91 (IEEE Address) .............
Program 92 (Freq) .....................
Program 93 (Diagnostics). ..............
Program 94 (MX + B Status) ...........
Program 95 (Multiplexer) ...............
Program 96 (CAL) .....................
FRONT PANEL TRIGGERING ...........
EXTERNAL TRIGGERING ...............
External Trigger .......................
Voltmeter Complete. ...................
Triggering Example ....................
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
.............
2-25
............. Z-26
............. 2-26
............. Z-26
............................
2-27
............................ 2-27
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
...... 2.28
...... 2.29
...... 2.29
......
2-29
...... 2.29
...... Z-30
...... 2-30
...... 2-30
...... 2-31
...... 2-31
...... 2-31
...... 2.32
SECTION 3-IEEE-488 PROGRAMMING
3.1
3.2
3.3
3.3.1
3.3.2
3.3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5
3.6
3.6.1
3.6.2
3.6.3
3.7
3.7.1
3.7.2
3.7.3
3.8
3.8.1
3.8.2
3.8.3
3.8.4
3.9
3.9.1
3.9.2
3.9.3
3.9.4
3.9.5
3.9.6
3.9.7
3.9.8
3.10
ii
INTRODUCTION ........................................................................... 3-l
BUS DESCRIPTION.. ....................................................................... 3-l
IEEE-488 BUS LINES ........................................................................ 3-2
Data Lines ................................................................................ 3-2
Bus Management Lines .................................................................... 3-2
Handshake Lines .......................................................................... 3-2
BUS COMMANDS .......................................................................... 3-3
Uniline Commands.. ... . .................................................................. 3-4
Universal Commands.. .................................................................... 3-4
AddressedCommands ..................................................................... 3-5
Unaddressedcommands ................................................................... 3-5
Device-Dependent Commands .............................................................. 3-5
COMMAND CODES ........................................................................ 3-5
COMMAND SEQUENCES ................................................................... 3-7
Addressed Command Sequence ............................................................. 3-7
Universal Command Sequence .............................................................. 3-7
Device-Dependent Command Sequence ..................................................... 3-7
HARDWARE CONSIDERATIONS ............................................................. 3-7
Typical Controlled Systems ................................................................. 3-7
BusConnections .......................................................................... 3-8
Primary Address Programming. ............................................................ 3.10
SOFTWARE CONSIDERATIONS ............................................................. 3.10
Controller Handler Software ............................................................... 3-10
Interface BASIC Programming Statements ................................................... 3.10
Interface Function Codes .................................................................. 3-11
IEEE Command Groups ................................................................... 3.12
GENERAL BUS COMMAND PROGRAMMING. .............................................. 3-12
REN(RemoteEnable) ..................................................................... 3.1~2
IFC(InterfaceClear) ....................................................................... 3.13
LLO(IocalLockout) ...................................................................... 3.13
GTL (Go To Local) and Local .............................................................. 3.13
DCL(DeviceClear) ....................................................................... 3-n
SDC(Send Device Clear) .................................................................. 3-14
GET (Group Execute Trigger) .............................................................. 3-14
Serial Polling (SPE, SPD) .................................................................. 3.14
DEVICE-DEPENDENT COMMAND PROGRAMMING ......................................... 3-15

3.10.1
3.10.2
3.10.3
3.10.4
3.10.5
3.10.6
3.10.7
3.10.8
3.10.9
3.10.10
3.10.11
3.10.12
3.10.13
3.10.14
3.10.15
3.10.16
3.10.17
3.10.18
3.10.19
3.10.20
3.10.21
3.10.22
3.10.23
3.11
3.11.1
3.11.2
3.12
3.13
3.x3.1
3.X3.2
3.13.3
3.w.4
3.x3.5
3.X3.6
3.w.7
3.13.8
3.x3.9
Execute(X) ............................................................................... 3.19
Function(F) .............................................................................. 3-1~
Range(R) ................................................................................ 3-19
Zero(Z) ................................................................................. 3-20
Filter(P)............................................................................~ .... 3.20
Rate(S) .................................................................................. 3.21
Trigger Mode (T) ......................................................................... 3.21
Reading Mode(B) ........................................................................ 3.22
Data Store Interval (Q) and Size (1) ........................................................ 3.22
Value (V) and Calibration (C) .............................................................. 3.23
Default Conditions (L) .................................................................... 3.24
Data Format(G) .......................................................................... 3-24
SRQ Mask (M) and Status Byte Format. .................................................... 3.25
EOI and Bus Hold-Off Modes (K) .......................................................... 3.28
Terminator (Y) ............................................................................ 3.28
Status(U) ............................................................................... 3.2’)
Multiplex (A) ..................................................................... ... ~, 3.33
Delay(W) ............................................................................... 3.33
Self-Test(J) ............................................................................... R-33
Hit Button(H) ........................................................................... 3-3-1
Display(D) .............................................................................. 3-W
Reference Junction (0) .................................................................... 3-35
Exponential Filter (N) .....................................................................
3.36
FRONT PANEL MESSAGES ................................................................. 3.36
Bus Error ................................................................................
3-36
Trigger Overrun Error ..................................................................... 3.37
BUS DATA TRANSMISSION TIMES ......................................................... 3.37
TRANSLATOR SOFTWARE ................................................................. 3-37
Translator Format ......................................................................... 3.37
Wild Card($) ............................................................................... 3-3’)
NEW and OLD .......................................................................... 3-39
Combining Translator Words .............................................................. 3-3’)
Combining Translator Words with Keithley IEEE-488 Commands .............................. 3-40
Executing Translator Words and Keithley IEEE Commands ......................... ......... 3-40
SAVE .................................................................................... 3-41
LIST ..................................................................................... 3-41
FORGET ................................................................................. 3.41
SECTION 4-PERFORMANCE VERIFICATION
4.1
4.2
4.3
4.4
4.5
4.5.1
4.5.2
4.5.3
4.5.4
4.55
4.5.6
INTRODUCTION ........................................................................... 4-l
ENVIRONMENTALCONDITIONS ............................................................ 1-1
INITIAL CONDITIONS.. .................................................................... 4-l
RECOMMENDED TEST EQUIPMENT. ........................................................ 4-I
VERIFICATION PROCEDURES ...................................................... ........ 4-I
DC Volts Verification.. ..................................................................... 1-2
TRMS AC Volts Verification ................................................................. 4-3
OHMS Verification ........................................................................ 4-4
DC Current Verification .................................................................... 4-5
TRMS AC Current Verification .............................................................. 4-h
RTD Temperature Verification ............................................................. 4-7
SECTION 5-THEORY OF OPERATION
5.1 INTRODUCTION ..,,...........,......,....,.,,.,...................................~....~. 5-l
iii

5.2 OVERALL FUNCTIONAL DESCRIIJTION ..................................................... 5-l
5.3 ANALOG CIRCUITRY ....................................................................... 5-l
5.3.1 Input Signal Conditioning .................................................................. 5-l
5.3.2 Multiplexer ............................................................................... 5-6
5.3.3 +Z.lV Reference Source .................................................................... 5-8
5.3.4 Input Buffer Amplifier ..................................................................... 5-8
5.4 AIDCONVERTER ........................................................................... 5-8
5.5 CONTROLCIRCUITRY.. ................................................................... 5-10
5.6 DIGITAL CIRCUITRY ....................................................................... 5-10
5.6.1 Microcomputer ........................................................................... 5-10
5.6.2 Display Circuitry .......................................................................... 5-10
5.7 POWER SUPPLIES ......................................................................... 5-10
SECTION 6-MAINTENANCE
6.1 INTRODUCTION ........................................................................... 6-l
6.2 LINE VOLTAGE SELECTION ................................................................. 6-l
6.3 FUSEREPLACEMENT ....................................................................... 6-l
6.3.1 Line Fuse ................................................................................. 6-l
6.3.2 Current Fuse. ............................................................................. 6-2
6.4 MODEL 1930 TRMS ACV OPTION INSTALLATION ............................................ 6-2
6.5 MODEL 1931 CURRENT OPTION INSTALLATION ............................................ 6-3
6.6 CALIBRATION .............................................................................. 6-3
6.6.1 Recommended Calibration Equipment ....................................................... 6-3
6.6.2 Environmental Conditions .................................................................. 6-3
6.6.3 Warm-Up Period .......................................................................... 6-3
6.6.4 Calibration Switch ......................................................................... 6-5
6.6.5 Front Panel Calibration. .................................................................... 6-5
6.6.6 IEEE-488 Bus Calibration ................................................................... 6-6
6.6.7 Calibration Sequence ....................................................................... 6-7
6.68 DC Volts Calibration ....................................................................... 6-7
6.6.9 Resistance Calibration ...................................................................... 6-8
6.6.10 TRMS AC Volts Calibration ................................................................ 6-10
6.6.11 DC Current Calibration. ................................................................... 6-13
6.6.12 TRMS AC Current Calibration ............................................................. 6-14
6.7 DISASSEMBLYINSTRUCTIONS ............................................................. 6-15
6.8 SPECIAL HANDLING OF STATIC-SENSITIVE DEVICES ...................................... 6-21
6.9 TROUBLESHOOTING ...................................................................... 6-21
6.9.1 Recommended Test Equipment ............................................................ 6-22
6.9.2 Power-Up Self Test ....................................................................... 6-22
6.9.3 Program 93.Self Diagnostic Program. ....................................................... 6-23
6.9.4 Iowa Supplies ........................................................................... 6-23
6.9.5 Signal Conditioning Checks ............................................................... 6.23
6.9.6 Digital and Display Circuitry Checks ....................................................... 6.23
SECTION 7-REPLACEABLE PARTS
7.1 INTRODUCTION ............................................................................ 7-l
7.2 PARTS LIST ................................................................................. 7-l
7.3 ORDERING INFORMATION ................................................................. 7-l
7.4 FACTORY SERVICE.. ........................................................................ 7-l
7.5 SCHEMATIC DIAGRAMS AND COMPONENT LOCATION DRAWINGS ......................... 7-l
iv

LIST OF ILLUSTRATIONS
2-l
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
Z-10
2-11
3-l
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
4-l
4-2
4-3
4-4
4-5
4-6
4-7
4-8
Connections for DC Volts Verlflcation.......................................................... 4-2
Connections for TRMS AC Volts Verification ................................................... 4-3
Maximum Input TRMS AC Voltage ............................................................ 4-4
Connections for Ohms Verification (200%20kn) Range .......................................... 4-4
Connections for Ohms Verifications (200k0-200MR Ranges). ..................................... 4-S
Connections for DC Current Verification. ...................................................... 4-h
Connections for TRMS AC Current Verification ................................................. 1-7
Connections for RTD Temperature Verification. ................................................. -1-7
5-l Overall Block Diagram ...............................................
5-2 Input Configuration During 2 and 4-Terminal Resistance Measurements
5-3 Ohms Source (2k12Range Shown) ....................................
s-4 Resistance Measurement Simplified Circuitry ..........................
5-5 JFET Multiplexer ....................................................
5-6 Multiplexerl’hases .................................................
5-7 A/D Converter Simplified Schematic ..................................
5.2
5.3
i-4
5-j
S-6
j-7
5-9
6-l Models 1930 and 1931 Installation. ........................................................... h-4
6-2 DC Volts Calibration Configuration (2OOmV and 2V Ranges) ..................................... b-7
6-3 DC Volts Calibration Configuration (ZOV-1OOOVRanges), ......................................... 6-S
6-4 Four-Wire Resistance Configuration (200%20kO Ranges) ......................................... 6-Y
6-5 Two-Wire Resistance Calibration Configuration (200k0-ZOOM0 Ranges). ........................... 6-9
6-6 Flowchart of AC Volts Calibration Procedure .................................................. 6-11
6-7 TRMS AC Volts Calibration Adjustments. ..................................................... 6-12
6-8 TRMS AC Volts Calibration Configuration ..................................................... h-l3
6-9 DC Current Calibration Configuration ........................................................ 6.14
6-10 TRMS AC Current Calibration Configuration .................................................. h-15
Model193A Front Panel ...................................................................... 2-7
Model193ARearPanel ....................................................................... 2-7
DC Voltage Measurements ................................................................... 2.13
TRMS AC Voltage Measurements ............................................................ 2.14
Two-Terminal Resistance Measurements ....................................................... 2-16
Four-Terminal Resistance Measurements. ...................................................... 2-16
Current Measurements.. .................................................................... 2-16
RTD Temperature Measurements.. ........................................................... 2-17
External Pulse Specifications ................................................................ 2-31
Meter Complete Pulse Specifications ......................................................... 2-32
External Triggering Example.. ............................................................... 2-33
IEEE-488 Bus Configuration .............. ...... ...... ...... 3-2
IEEE-488 Handshake Sequence ........... ...... 3-3
Command Groups ...................... ...... ...... 3-6
System Types ........................... ...... ...... 3-8
Typical Bus Connections ................. ...... 3-x
IEEE-488 Connections. ................... ...... 3-Y
Model 193A IEEE-488 Connector ........ ...... 3-Y
Contact Assignments. ................... ...... ...... 3-10
General Data Format ................... ...... ...... ...... 3-26
SRQ Mask and Status Byte Format ..... ...... ...... ...... 3-26
UO Status Word and Default Values ...... ...... ...... ...... 3-30
Ul Error Status Word. .................. ...... ...... 3-32
Hit Button Command Numbers ......... ...... ...... 3-34

6-11 Co”“ectors..................................................... ........................... 6-17
6-12 Model 193A Exploded View. ........................... 6-19
7-1 Jumper Board, Component Location Drawing, Dwg. No. 193.160.
7-2 Display Board, Component Location Drawing, Dwg. No. 193.110
7-3 Display Board, Schematic Diagram, Dwg. No. 193.116
7-4 Digital Board, Component Location Drawing, Dwg. No. 193.100
7-5 Digital Board, Schematic Diagram, Dwg. No. 193-106
7-6 Analog Board, Component Location Drawing, Dwg. No. 193.120
7-7 Analog Board, Schematic Diagram, Dwg. No. 193.126
7-8 Model 1,930,Component Location Drawing, Dwg. No. 1930.100
7-9 Model 1930, Schematic Diagram, Dwg. No. 1930.106
710 Model 1931, Component Location Drawing, Dwg. No. 1931-100
7-11 Model 1931, Schematic Location Drawing, Dwg. No. 1931.106
......
......
......
......
......
......
......
......
......
......
......
.............. 7-3
.............. 7-4
.............. 7-5
.............. 7-10
.............. 7-11
............. 7.22
............. 7-23
............. 7.34
............. 7-35
............. 7-38
............. 7-39
vi

LIST OF TABLES
2-l
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
3-l
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-n
3-14
3-15
3-16
3-17
3-18
IEEE-488 Bus Command Summary. .......................................................... 3-4
Hexadecimal and Decimal Command Codes ................................................... 3-5
Typical Addressed Command Sequence ...................................... ................ 3-7
Typical Device-Dependent Command Sequence ................................................ 3-7
IEEE Contact Designation .................................................................... 3-9
BASIC Statements Necessary to Send Bus Commands ......................................... 3-11
Model 193A Interface Function Codes ........................................................ 3.11
IEEE Command Groups. .................................................................... 3.12
General Bus Commands and Associated BASIC Statements .................................... 3-12
Factory Default Conditions .................................................................. 3-14
Device-Dependent Command Summary ...................................................... 3-16
Range Command Summary ................................................................. 3-20
High Speed Data Store .................................................................... 2-23
SRQ Command Parameters .................................................................. 3-27
Bus Hold-Off Times ........................................................................ 3-28
Trigger to Reading-Ready Times (DCV Function) .............................................. 3-37
Translator Reserved Words and Character. .................................................... 3-38
Translator Error Messages .................................................................... 3-38
4-l Recommeded Test Equipment ..............
4-2 Limits for DC Volts Verification .............
4-3 Limits for TRMS AC Volts Verification. ......
4-4 Limits for Ohms Verification ...............
4-5 Limits for DC Current Verification ..........
4-6 Limits for AC Current Verification ..........
4-7 Limits for RTD Temperature Verification ....
5-l
6-l
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
6-12
6-13
Ranging Information ......................................................................... 5.3
Line Voltage Selection ........................................................................ 6-l
Line Fuse Replacement ...................................................................... 6-2
Current Fuse Replacement ................................................................... 6-2
Recommended Calibration Equipment .........................................................
DC,Volts Calibratiqn ......................................................................... 6;
Resistance Calibration ....................................................................... 6-10
TRMS AC Volts (Model 1930) Calibration ..................................................... 6-13
DC Current Cahbratmn
....................................................................... 6-14
TRMS AC Current Calibration ............................................................... 6-15
Static-Sensltwe Devzes ..................................................................... 6.21
Recommended Troubleshooting Mode ........................................................
Model 193A Troubleshooting Mode .......................................................... 6;:
Power Supply Checks ...................................................................... h-28
Factory Default Conditions ................................................................... 2-l
Front PanelPrograms ........................................................................ 2-4
Error and Warning Messages ................................................................. 2-9
Internal Filter ............................................................................... 2.12
Resistance Ranges .......................................................................... 2.15
Corresponding Voltage Reference Levels for Impedance References .............................. 2.19
Comparison of Average and TRMS Meter Readings. ........................................... 2-21
High Speed Data Store ..................................................................... 2.22
Example MX + B Readings ................................................................. Z-28
......
......
......
......
......
......
......
......
......
......
......
vii

6.14 Digital Circuitry Checks ............................................................... 6-28
6-15 Display Circuitry Checks .............................................................. 6-29
7-l Display Board, Parts List ..............................................................
7-2 Digital Board, Parts List ..............................................................
7-3 Analog Board, Parts List,, ............................................................
7-4 Model 1930, Parts List .................................................................
7-5 Model 1931, Parts List. ................................................................
7-6 Model 193A Mechanical Parts List ......................................................
...... 7-2
...... 7-7
715
7-31
7-37
7-41
vttt

SECTION 1
GENERAL INFORMATION
1.1 INTRODUCTION
The Keithley Model 193A System DMM, with the TRMS
AC Volt and Current options installed, is a six function auto-
ranging digital multimeter. At 6% digit resolution, the LED
display can display ~2,200,OOOcounts. The range of this
analog-to-digital (A/D) converter is greater than the nor-
mal *1,999,999 count AID converter used in many 6% digit
DMMs. The built-in IEEE-488 interface makes the instru-
ment fully programmable over the IEEE-488 bus. With the
TRMS ACV option and the Current option installed, the
Model 193A can make the following basic measurements:
1. DC voltage measurements from 1OOnVto lOOOV.
2. Resistance measurements from 1OOpflto ZOOMR.
3. RTD temperature measurements from -1OOOCto 63O’C.
4. TRMS AC voltage measurements from I$/ to 700V.
5. DC current measurements from 1nA to 2A.
6. TRMS AC current measurements from 1nA to 2A.
In addition to the above mentioned measurement capa-
bilities, the Model 193A can make dB and TRMS AC + DC
measurements.
1.2 FEATURES
Some important Model 193A features include:
l 14Character Alphanumeric Display-Easy to read 14 seg-
ment LEDs used for readings and front panel messages.
l High Speed Measurement Rate-1000 readings per
second.
l Zero-Used to cancel offsets or establish baselines. A zero
value can be rogrammed from the front panel or over
the IEEE-488 &us.
l Filter-The weighted average digital filter can be set for
1 to 99 readings from the front panel or over the bus.
l Data Store-An internal buffer that can store up to 500
readings is accessible from either the front panel or over
the bus.
l Digital Calibration-The instrument may be digitally
calibrated from either the front panel or over the bus.
l User Programmable Default Conditions-Any instrument
measurement configuration can be established as
the power-up default conditions.
l Translator Software-User defined words can be used to
replace standard command strings over the IEEE488 bus.
l Thermocouple (TC) temperature measurements con be
made over the IEEE-488 bus.
1.3 WARRANTY INFORMATION
Warranty information may be found on the inside front
cover of this manual. Should it become necessary to exer-
cise the warranty, contact your Keithley representative or
the factory to determine the pmper course of action.
Keithley Instruments maintains service facilities in the
United States, United Kingdom and throughout Europe.
Information concerning the application, operation or ser.
vice of your instrument may be directed to the applications
engineer at any of these locations. Check the inside front
cover for addresses.
1.4 MANUAL ADDENDA
Information concerning improvements or changes to the
instrument which occur after the printing of this manual
will be found on an addendum sheet included with this
manual. Be sure to review these changes before attemp-
ting to operate or service the instrument.
1.5 SAFETY SYMBOLS AND TERMS
The following safety symbols and terms are used in this
manual or found on the Model 193A.
The A symbol on the instrument denotes that the user
should refer to the operating instructions in this manual.
The M on the Instrument denotes that a potential of
1OOW or more may be present on the terminal(s). Stand-
ard safety practices should be observed when such
dangerous levels are encountered.
The WARNING used in this manual explains dangers that
could result in personal injury or death.
The CAUTION used in this manual explains haz.ards that
could damage the instrument.
l-l

GENERAL INFORMATION
1.6 SPECIFICATIONS
Detailed Model 193A specifications may be found preceding
the Table of Contents of this manual.
1.7 INSPECTION
The Model 193A System DMM was carefully inspected,
both electrically and mechanically before shipment. After
unpacking all items from the shipping carton, check for any
obvious signs of physical damage that may have occurred
during transit. Report any damage to the shipping agent.
Retain and use the original packing materials in case reship-
ment is necessary. The following items are shipped with
every Model 193A order:
Model 193A System DMM
Model 193A Instruction Manual
Additional accessories as ordered.
If an additional instruction manual is required, order the
manual package (Keithley Part Number 193-901-00). The
manual package includes an instruction manual and any
applicable addenda.
1.6 USING THE MODEL 193A MANUAL
This manual contains information necessary for operating
and servicing the Model 193A System DMM, TRMS ACV
option and the Current option. The information is divided
into the following sections:
l Section 1 contains general information about the Model
193A including that necessary to inspect the instrument
and get it operating as quickly as possible.
l Section 2 contains detailed operating information on us-
ing the front panel controls and programs, making con-
nections and basic measuring techniques for each of the
available measuring functions.
l Section 3 contains the information necessary to connect
the Model 193A to the IEEE-488 bus and program
operating modes and functions from a controller.
l Section 4 contains performance verification procedures
for the instrument. This information will be helpful if you
wish to verify that the instrument is operating in com-
pliance with its stated specifications.
l Section 5 contains a description of operating theory.
Analog, digital, power supply, and IEEE-488 interface
operation is included.
-
1-2
l Section 6 contains information for servicing the instru-
ment, This section includes information on fuse replace-
ment, line voltage selection, calibration and
troubleshooting.
l Section 7 contains replaceable parts information.
1.9 GETTING STARTED
The Model 193A System DMM is a highly sophisticated in-
strument with many capabilities. To get the instrument up
and running quickly use the following procedure. For com-
plete information on operating the Model 193A consult the
appropriate section of this manual.
POWW-Up
1. Plug the line cord into the rear panel power jack and
plug the other end of the cord into an appropriate,
grounded power source. See paragraph 2.2.1 for more
complete information.
2. Press in the POWER switch to apply power to the in-
strument. The instrument will power up to the 1OOOVDC
range.
Making Measurements
1. Connect the supplied safety shrouded test leads to the
front panel VOLTS HI and LO input terminals. Make
sure the INPUT switch is in the out (FRONT) position.
2. To make a voltage measurement, simply connect the in-
put leads to a DC voltage surge (up to 1OOOV)and take
the reading from the display.
3. To change to a different measuring function, simply
press the desired function button. For example, to
measure resistance, press the OHMS button.
Using Data Store
Storing Data:
1. Press the DATA STORE button. The DATA STORE in-
dicator will turn on and a storage rate (in seconds) will
be displayed.
2. Select an interval, other than 000.000, using the 4 and
w, and data buttons.
3. Press the ENTER button. The buffer size will be
displayed. Size 000 indicates that data will overwrite after
500 readings have been stored.
4. If a different buffer size is desired, enter the value us-
ing the number buttons (0 through 9).
5. Press the ENTER button to start the storage process.

GENERAL INFORMATION
The data store mode can be exited at any time before the
start of the storage process by pressing the RESET button.
Once storage has commenced, the storage process can be
stopped by pressing any function button. See paragraph
2.7.1 for complete information on storing data.
Recalling Data:
1. Press the RECALL button. The buffer location of last
stored reading will be displayed.
2. To read the data at a different manor location, enter
the value using the number buttons O-9).
Y
3. Press the ENTER button. The reading and the memory
location will be displayed.
4. The A and 7 buttons can be used to read the data in
all filled memory locations.
5. To read the highest, lowest and average reading stored
in the buffer, press the number 1,2 and 3 buttons respec-
tively. Note that the memory location of the highest and
lowest reading is also displayed. The average reading is
displayed along with the number of readings averaged.
The recall mode can be exited by pressing the RESET but-
ton. See paragraph 2.7.2 for complete information on data
recall.
Using Front Panel Programs
Program selection is accomplished by pressing the PRGM
button followed by the button(s) that corresponds to the
program number or name. For example, to select Program
91 (IEEE status), press the PRGM button and then 9 and
1buttons. Table 2-2 lists and briefly describes the available
front panel programs. Once a
following general rules will Program is selected the app y:
1. A displayed program condition can be entered by press-
ing the ENTER button.
2. Program conditions that prompt the user with a flashin
digit can be modified usmg the data buttons (0 throug a
9 and +) and the cursor control buttons (manual range
buttons).
3. Programs that contain alternate conditions can be
dis K layed by ressin one of the manual range buttons.
Eat press o
P P
one o these buttons toggles the display
between the two available conditions.
4. A program will be executed when the pressed ENTER
button causes the instrument to exit the program mode.
5. A pro ram can be exited at an time and thus not ex-
ecute 1, by pressing the RESEif button.
Paragraph 2.8 provides the detailed information for using
the front panel programs.
1.10 ACCESSORIES
The following accessories are available to enhance the
Model 193As, capabilities.
Model 1301 Temperature Probe-The Model Uol is a rug-
ged low cost temperature probe designed to allo\v temper-
ature measureme”ts from -55 to 150°C.
Model 16008 High Voltage Probe-The Model 1booBextends
DMM measurements to 40kV.
Model 1641 Kelvin Test Lead Set-The Model 1641 has
special clip leads that allow 4-terminal measurements to be
made while making “nly two c”nnectims.
Model 165150.Ampere Current Shunt-The Model 1651is
an external O.OOlR *l% 4.terminal shunt, which permits
current measurements from 0 to 50A AC or DC.
Model 1681 Clip-On Test Lead Set-The Model 1681 con-
tains two leads, 1.2m (48’) long terminated with banana
plugs and spring action clip probes.
Model 1682A RF Probe-The Model 1682A permits voltage
measurements from 1OOkHzto 250MHz. AC to DC transfer
accuracy is +ldB from 1OOkHr to 250MHz at IV, peak
responding, calibrated in RMS of a sine wave.
Model 1685 Clamp-On AC Probe-The .Model 1685
measures AC current by clamping on to a single conduc-
tor. Interruption of the circuit is unnecessary. The Model
1685detects currents by sensing the changing magnetic field
produced by the current flow.
Model 1751 Safety Test Leads-Finger guards and shroud-
ed banana plugs help minimize the chance “1 making con-
tact with live circuitry.
Model 1754 Universal Test Lead Kit-The Model 1754 is rl
12 piece test lead kit, with interchangeable plug-in ac-
cessories. Included in the kit is one set of test leads (l-red,
l-black), two spade lugs, two standard banana plugs, two
phone tips (0.06 DIA.), two hooks and miniature alligator
clips (with boots).
Model 1930 TRMS AC Volt 0 tion-The Model 1930 is d
True Root Mean Square (TRM ! ) AC plug-in option for the
Model 193A. This option allows the instrument to measure
the TRMS value of an AC signal. When the Model 1Y30
1-3