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INSTRUCTION MANUAL
Digital Multimeter
Model 5900
WARRANTY
We warrant each of our products to be free from defects in material
and workmanship. Our obligation under this warranty is to repair
or replace any instrument or part thereof which, within a year after
shipment, proves defective upon examination. We will pay local
domestic surface freight costs.
To exercise this warranty, write or call your local Keithley repre-
sentative, or contact Keithley headquarters in Cleveland, Ohio.
You will be given prompt assistance and shipping instructions,
REPAIRS AND
CALIBRATION
Keithley Instruments maintains a complete repair and calibration
service as well as a standards laboratory in Cleveland, Ohio. A
service facility is also located in Los Angeles for our west coast
customers.
A Keithley service facility at our Munich, Germany office is
available for our customers throughout Europe. Service in the
United Kingdom'can be handled at our office in Reading. Addition-
ally, Keithley representatives in most countries maintain service
and calibration facilities.
To insure prompt repair or recalibration service, please contact
your local field representative or Keithley headquarters directly
before returning the instrument. Estimates for repairs, normal
recalibrations and calibrations traceable to the National Bureau of
Standards are available upon request.
KEITHLEY
The measurement engineers.
Keithley Instruments, inc., 28775 Aurora Road, Cleveland, Ohio 44139. (216) 248-0400
European Headquarters: Heiglhofstrasse 5, D-8000 Munchen 70 West Germany, (0811) 7144065
Unlted Kingdom: 1 Boulton Road, Reading, Berkshire, (0734) 861287
France: 44 Rue Anatole France. F-91121 Palaiseau (01) 928-00-48
FOR YOUR SAFETY
Before undertaking any maintenance procedure,whether it
be a specific troubleshooting or maintenance procedure
described herein or an exploratory procedure aimed at
determining whether there has been a malfunction, read the
applicable section of this manual and note carefully the
WARNING and CADTlON notices contained therein.
The equipment described in this manual contains voltages
hazardousto human life and safety and which is capableof
inflicting personal injury. The cautionary and warning
notes arc included in this manual to alert operator and
maintenance personnel to the electrical hazards and thus
prevent personalinjury and damageto equipment.
If this instrument is to be powered from the AC Mains
through an autotransformer (such asa Vartac or equivalent)
ensure that the instrument common connector is con-
nected to the ground (earth) connection of the power
mains.
Before operating the unit ensure that the protective con-
ductor (green wire) is connected to the ground (earth)
protective conductor of the power outlet. Do not defeat
the protective feature of the third protective conductor in
the power cord by using a two conductor extension cord or
a three-prong/two-prongadapter.
Maintenance and calibration procedures contained in this
manual sometimescall for operation of the unit with power
appliedandprotective coversremoved. Readthe procedures
carefully and heed Warnings to avoid "live" circuit points
to ensureyour personalsafety.
Before operating this instrument,
1. Ensure that the instrument is configured to
operate on the voltage available at the power
source SeeInstallation section.
2. Ensure that the proper fuse is in place in the
instrument for the power source on which the
instrument is to be operated.
3. Ensure that all other devices connected to or in
proximity to this instrument are properly grounded
or connected to the protective third-wire earth
ground.
COPYRIGHT
Copyright 0 1976 by Keithley Instruments, Inc. Printed in the United
Statesof America. All rights reserved. This book or parts thereof may
not be reproduced in any form without written permission of the
publishers.
PROPRIETARY NOTICE
This document and the technical data herein disclosed,are proprietary
to Keithley Instruments, Inc., and shall not, without expresswritten
permission of Keithley Instruments, Inc., be used, in whole or in part
to solicit quotations from a competitive sourceor usedfor manufacture
by anyone other than Keithley Instruments, Inc. The information
herein has beendevelopedat private expense,and may only be usedfor
operation and maintenance reference purposes or for purposes of
engineering evaluation and incorporation into technical specifications
and other documents which specify procurement of products from
Keithley Instruments, Inc.
TABLE OF CONTENTS
Section Title Page
1 GENERALDESCRIPTION . . I-1
1.1 Introduction 1-l
1.7 Options .' I-I
1.9 Model 42 Remote Programming I-1
1.11 Rear Input Options(-I, -1s) I-1
1.13 Rack-Mounting Flanges(403402) 1.2
1.15 High-VoltageProbe 1-2
1.17 Current Shunt Set (651) l-2
1.19 Electrical Description 1-2
I .26 MechonicalDescription I.3
I .32 Specifications l-3
2 mSTALLATION& OPERATION 2-1
2.1 Unpacking and Inspection ......... 2-l
2.4 Bench Operation ............ 2-l
2.6 Rack Mounting ............ 2-1
2.8 Power Connections ............ 2-l
2.12 Input/Output Cabling .......... 2-2
2.13 Binding Posts ............ 2-2
2.16 Rear Input Connector ......... 2-2
2.18 Manual Operation ........... 2-2
2.19 Controls ............. 2-2
2.21 Display ............... 2-2
2.23 MeasurementConnections. ........ 2.4
2.24 BasicVoltage Measurement ....... 24
2.28 Ohms Measurement .......... 24
2.42 Ratio Measurements .......... 2-7
2.44 SystemCapabilities ........... 2-7
2.46 Printer Output . JZOI ......... 2-8
2.48 ProgramInput. ........... 2-8
2.50 Logic Levelsand Electronic Interface ..... 2-8
2.54 Driving the Inputs .......... 2-B
2.56 TTL Loading Conditions ........ 2-8
2.59 Exceptions to Input Loading Conditions ... 2.10
2.60 `ITL Output Capabilities ........ 2-10
2.62 Thning Sequence........... 2.10
2.64 Other ReadCommandOptions ...... 2.11
2.66 Reading Rates. ........... 2-12
2.68 Superfast ............. 2.12
2.70 Printer Output ............ 2-13
2.72 Numerical Data ........... 2-13
2.75 Function Data. ........... `2.14
2.77 RangeData. ............ 2.14
111
980453
TABLE OF CONTENTS (continued)
Section
2.79 "NO" Indication 2.14
2.81 StatusOutput Lines 2.15
2.83 Input Control Lines 2-15
2.84 SystemDirect Command 2.16
2.86 RemoteProgramming 2.16
2.88 SystemControl 2.16
2.90 Function Programming 2.16
2.93 RangeProgramming 2.17
2.95 + Five Volts 2.17
2.97 Hold 2-17
2.99 ReadCommands 2.17
2.101 Timeouts 2.17
2.103 Data Inhibit 2-17
2.105 ProgramStorage 2-17
2.107 Superfast 2.18
2.109 Adding/Removing Accessories 2.18
3 SPECIFICATIONTESTS ..... 3.1
3.1 General ........... 3-l
3.4 Required Equipment ...... 3-l
3.6 Procedure .......... 3-1
4 THEORY OF OPERATION . . 4.1
4.1 General 4-l
4.3 MechanicalDescription 4-l
4.5 Electrical Description 4-l
4.7 SignalConditioning Section 4-1
4.10 Switching Board 4-l
4.14 OhmsConverter 4-1
4.18 ScalingAtnplifier 4.3
4.2 1 AveragingAC Converter 4.9
4.24 RMSACConverter 4-9
4.28 Attenuator 4.9
4.30 Isolator 4.9
4.33 Switching Bypass. 4-9
4.35 Integration 4-9
4.37 Digitizer, 4.12
4.52 Ratio, Standard 4-14
4.54 Ratio,Option 4.15
4.56 Display Board 4.15
4.70 Main Logic and Control Circuitry 4.17
4.12 Control Logic 4-17
4.74 ProgramCycle 4.19
iv
980453
TABLE OF CONTENTS (continued)
Section Title
4.76 Display Logic .................. 4-19
4.78 Superfast ................... 4.19
4.80 PowerSupplies ................. 4.19
4.82 Program. ................... 4.20
5 CALIBRATION ................. 5-1
5.1 scope 5-l
5.3 General .................... 5-l
5.5 Required Equipment .............. 5-l
5.7 FabricatedCalibration Equipment .......... 5-l
5.10 DC Voltage Sources ............... 5-l
5.19 AC Voltage Sources ............... 5-4
5.23 Preliminary Procedure ............... 5-4
5.24 Warmup. .................. s-4
5.26 Familiarization ................ 54
5.28 Calibration Points ............... 54
5.30 Environmental Considerations ........... 5-4
5.32 Recalibration Procedure . 54
5.34 Isolator Zero ................. 5-6
5.35 DC Voltage Zero and Gain. 5-6
5.36 DC RangeCalibration 5-6
5.38 OhmsCalibration. ................ 5-6
5.39 ohms Zero .................. 5.6
5.40 Ohms Range .................. 5-7
5.41 AC Calibration (Model 33). 5.7
5.42 AC Converter Zero ............... 5.7
5.43 Frequency Response .............. s-7
5.44 RMSAC Calibration (Model 32) 5-9
5.45 4-WireRatio Calibration .............. s-10
5.46 Troubleshooting ................. s-10
5.48 Troubleshooting Equipment ............ s-10
5.50 Power Supply Check ............... S-10
5.52 Operational Check ............... 5-l 1
5.54 Preliminary Instrument Setup ........... 5-11
5.55 Circuit Descriptions ............... 5.11
5.86 Board Revision ................. s-14
DRAWINGS . . . . . 6-1
1 PARTSLIST . . . . . . . . . . . 7-1
v/vi blank
LIST OF ILLUSTRATIONS
Figure Title Page
1.1 Block Diagram -Model 5900 l-2
1.2 Dimensions, l-3
2.1 Rack Mount Installation' 2-l
2.2 Cabling Diagram,Binding Posts 2-2
2.3 Cabling Diagram,Rear Input 2-2
2.4 Readout 2-2
2.5 Front Panel 2-3
2.6 BasicVoltage Measurement Connections 2.4
2.7 Maximum RMSlnput Voltage 2-4
2.8 Two Wire Ohms Measurements 2-s
2.9 Four Wire OhmsMeasurement 2-6
2.10 Rear Panel 2-8
2.11 MeasurementSequence. 2-9
2.12 CommandTiming 2-11
2.13 Minimum ReadRate vs. Input 2.12
2.14 SuperfastRead Rate (Worst Case) 2.13
2.15 Pin Assignments 5201 PRINTER OUT 2-14
2.16 Pin Assignments 5202 PROGRAM INPUl 2-16
2.17 Jumper Location Z-IX
4.1 MechanicalAssembly 4-2
4.2 Signal Flow, Loaded DVM. 4.3
4.3 Switching Board 4-4
4.4 Signal Flow of Switching Board 4.5
4.5 OhmsConverter 4-6
4.6 OhmsMeasurementSystems 4-7
4.7 ScalingAmplifier 4-R
4.8 AveragingAC Converter 4-8
4.9 RMS AC Converter 4.10
4.10 Attenuator/Isolator DC. 4.11
4.11 Signal Flow, Switching Bypass 4.12
4.12 Digitizer. 4-13
4.13 Integration Timing Diagram 4.14
4.14 4.Wire Ratio Option 4-1s
4.15 Display Board 4.15
4.16 Main Logic&Control Block Diagram 4-18
4.17 ProgramBlock Diagram. 4-20
5.1 10 Volt Source 5-2
5.2 GeneratingAccurate DC Levels s-2
5.3 AC Source s-3
5.4 Adjustment Locations s-s
5.5 Ohms Input Connection S-6
5.6 Connectionsfor Ohms RangeAdjustment 5.7
5.7 4.WireConnections s-7
5.8 AC Adjustment Locations S-8
5.9 4.Wire Ratio Adjustment Locations S-IO
vii
980453
LIST OF ILLUSTRATIONS (continued)
Figure Title Page
6.1 Layout, Logic and Interconnection ........... 6-3
6.2 Layout, Readout ................. 6.3
6.3 Schematic,Logic and Interconnection .......... 6-S
6.4 Schematic,Power Supply .............. 6-7
6.5 Layout, Attenuator ................ 6.8
6.6 Schematic,Attenuator ............... 6.9
6.7 Layout, Switching ................ 6-10
6.8 Schematic,Switching ............... 6-11
6.9 Layout, Isolator ................. 6.12
6.10 Schematic,Isolator ................ 6-13
6.11 Layout, IOV ReferenceAmplifier ........... 6.14
6.12 Layout, Digitizer ................. 6.14
6.13 Schematic,Digitizer and 1OVReferenceAmplifier ...... 6-15
6.14 Layout, Program ................. 6.16
6.15 Schematic,Program ................ 6.17
6.16 layout, Display ................. 6.18
6.17 Schematic,Display ................ 6.19
6.18 Layout, AC Converter ............... 6.20
6.19 Schematic,AC Converter .............. 6-21
6.20 Layout, RMS Converter .............. 6.22
6.21 Schematic,RMS Converter ............. 6.23
6.22 Layout, ScalingAmplifier .............. 6.24
6.23 Schematic,ScalingAmplifier ............. 6.25
6.24 Layout, Ohms Converter .............. 6-26
6.25 Schematic,OhmsConverter ............. 6-27
6.26 Layout, 4.Wire Ratio ............... 6.28
6.27 Schematic,4.Wir-s Ratio .............. 6.29
6.28 Layout,RearPanel ................ 6.30
6.29 Layout, Parallel Front-Rear Input (-1) .......... 6.3 1
6.30 Layout, Switchable Front.Rear Input (-IS) ........ 6-32
viii
LIST OF TABLES
Table Page
1.1 MeasurementCapability .......................... 1-1
1.2 Specifications 1-4
2.1 Operating Controls
................ .............. 1 1 : : 1 1 1 1 1 1 1 1 1 : 2.3
2.2 Maximum Input Voltage .......................... 2.4
2.3 Positive True Logic Relationships 2-a
2.4 RangeCodes(Printer Output) ............... : : : : : : : : : : : ,: : : : : 2.15
2.5 Function Programming .................. 2.17
2.6 RangeCodes(Programmet) ................ : : : : : : : : : 2.17
2.7 Timeouts ............... 2-18
2.8 Maximum Input Voltage .......... : : : : : : : : : : : : : : : : 2.18
3.1 Required Equipment 3-1
3.2 DC RangeCheck(Low Ranges) ..................... : : : : : : : : : : : : : : : 3.2
3.3 DC RangeCheck(High Ranges) ........................ 3-3
3.4 3.Wire Ratio Check ............... 3-4
3.5 4.Wire Ratio Check ............... : : : : : : : : : : : : : 3-s
3.6 DC Input Resistance. ........................... 3.6
3.7 Model 33 AC Converter RangeCheck ...................... 3-7
3.8 Model 32 AC Converter RangeCheck ................ 3-8
3.9 Ohms-Megohms RangeCheck. .................. : : : : : : 3-9
3.10 Common Mode Rejection (In DC Volts Function) ............... 3-10
3.11 Normal Mode Noise Rejection (In DC Volts Function) ............. : : : 3-11
3.12 Common Mode Rejection (In AC Volts Function) .............. 3.12
4.1 Switching Board RangeDecode .................... : : : : 4-1
4.2 RangeSwitch Code ................... 4.16
4.3 Autorange Logic .................... : : : : : : : : : 4-16
4.4 Relay Logic Coding ............................ 4.16
4.5 Annunciator Logic ............................ 4.17
4.6 "NO" Annunciator Logic .......................... 4.17
4.7 ProgramLogic Conversion .......................... 4-21
5.1 RequiredCalibration Equipment ....................... 5-a
5.2 Fixed Voltage Dividers ........................... S-l
5.3 DC SourceAccuracies ........................... s-3
5.4 AC SourceAccuracies ........................... s-4
5.5 PowerSupply Check S-II
5.6 OperationalCheck ......................... : : : : : : : : : : : : : : : s-1 1
5.7 Trollblesllooting Guide ........................... s-12
5.8 Troubleshooting Chart-Digitizer and 1OVReferenceAmplifier ............. s-13
5.9 Troubleshooting Chart. Isolator and Attenuator Boards ................ s-14
5.10 Troubleshooting Chart Optional Accessories ................... s-14
7.1 Table7.1 ............................... 7-1
7.2 List of Suppliers ............................. 7-l
980453 ix
SECTION 1 GENERAL DESCRIPTION
1.1 INTRODUCTION. until a single reading is commanded by an external com-
mand. The new measurementis then held until the next
1.2 The Model 5900 Digital Multimeter is a five-decade external command. In Periodic mbde (RATE control CW),
instrument with a sixth digit providing 60% overrange. The measurements madeautomatic+ly at the rate of approxi-
are
basic instrument is equipped for dc and dc/dc ratio meas- mately four per second.
urements on five ranges. With the addition of the optional
AC Converter, a-c and ac/dc ratio measurements four on 1.5 The basic Model 5900 includes an analog output
rangesare available. The Ohms Converter, also optional, voltage that is proportional to the parameter being meas-
adds ohms measurements eight ranges. Complete meas-
on ured (except ratio). The voltage, at 20 volts maximum, is
urement capability of a fully equipped instrument is tabu- availableat a rear panel connector.
lated in table 1.l.
1.6 Also included as standard equipment is a solid-state
Table 1.I - Measurement
Capability isolated BCD output. TTL-compatible output levelsof the
reading, function, range, etc., plus a print command are
FUNCTION 1
r provided. An additional line enablesa new reading to be
OhIllS AC & AC/DC commanded externally. An optional isolated remote pro.
RATIO grammingunit (Model 42) allows all operating commands to
DC & Dc/Dc (Model 52
RATIO (Model 32 be madeextcmally.
Ohms
or 33
Range (Basic 5900) Converter) AC Converter)
.lV I x I 1.7 OPTIONS.
1vI I
x I
I 1.8 All optional accessories having model numbers are
1ov X plug-in circuit boards that may be added at any time. A
calibrated accessory board can be installed without af-
IOOV I x I fecting the d-c calibration of the basic instrument. An
ooov I x I instrument shipped without PCB accessories will not be
equipped with a Function Switching PCB assembly. This
100. I I x board must be added when accessoryboards are installed.
.I KS2 X Analog accessories identified in table 1.l.
are
1Kn X 1.9 Model 42 Remote Programming.
10Kn 1 I x
1.10 The Model 42 Remote Programmingaccessoryal-
100 K$-l 1 I x lows the selection of function, range,filter, read command,
etc., to be made externally. Auto range selection is also
000 KS2 1 I x provided and appropriate timeouts are generatedinternally
lOMa/ I x when rangingtakesplace. RemoteProgramming"overrides"
all manual control settings to prevent erratic selections.
lOOMa 1 I x
Complete isolation of the programmingunit is achievedby
the useof photoauplers and pulse transformers.
1.3 Range can be selected manually or automatically
(autorange). In AUTO range,the proper rangefor a partic- 1.11 Rear Input Options (-1, -lB, -1s. -1SB).
ular measurementis selectedautomatically (full scaleis de-
fined as "100000" on any range). The instrument "up 1.12 Two rear input options are available for the Model
ranges" at 16U%of full scaleand "downranges" at 15%of 5900 DMM. The option designated-1 or -IB consistsof
full scale. Polarity selection is also automatic and is dis- connector 5204 on the back panel with input lines +
played on the readout. INPUT, + CURRENT, and GUARD wired in parallel with
the front panel input terminals; the option designated-1s
1.4 Two operating modes are provided. In Hold mode or -1SB is the sameas the -1 or -lB except that the front or
(RATE control on EXT), a measurement held (displayed)
is rear inputs are selectableby a switch on the front panel.
b I-I
980453
T T
1.13 Rack-Mounting Flanges (403402). 1.17 Current Shunt Set (651).
1.14 Rack.Mounting Flatages used where 1111'
are IIIS~~U- I .I8 The Current Shunt Set consists of six precision
ment is to be installed in a relay-rackor cabinet. sIllill assemblieswitb values selectedto produce a voltage
drop that, n~e:tsured millivolts. Ins a numerical value
in
cqual to 111~ current Ilow in milliamps or micro;tmps.
1.15 High-Voltage Probe (641).
1.19 ELECTRICAL DESCRIPTION.
1.16 The High.VoltageProbeextendsthe voltage rangeof
the instrument up to 10,000 volts (or 7SOOV rms). It is an 1.70 1be Model 5900 DMM is a dual slope integration
insulated prube containing a 1000:1 voltagedivider. instrument consistingof three main functional areas: signal
l-2
9804.53
conditioning, integrating, and control/display. A block dia- 1.28 The Function Switching board is used only when
gram of the instrument is shown in figure I, 1. either or both of the options (AC and Ohms) are installed.
With no options installed, the Function Switching board is
1.21 The signal conditioning section includes the replaced with the Switching Bypassboard. The Switching
Switching p-c board, AC Converter, Ohms Converter, Bypassmerely connects the + Input (from input connector)
Attenuator, and Isolator. The function of these circuits is directly to the Isolator input and the - Input to ground.
to convert the incoming signal to 10 MC, full scaleinto the
integrator. 1.29 At the rear edge of the Logic and Interconnection
assemblyis a PCB connector that extends to the rear panel
1.22 The Integrating section consists of the Integrator and serves as the BCD output connector 1201. If the
amplifier, Null Detector and + reference voltages. The optional Remote Program board is installed, it is mounted
function of these circuits is to convert the conditioned in. on stand-offs above the Logic and Interconnection board
put signal to an equivalent time period and to transmit this with the PROGRAM INPUT connector (J202) available at
iime period to the display portion of the DMM. the rear panel abovethe BCD OUTPUT connector.
1.23 Dual slope integration operates as follows in a 1.30 The POWER input connector 1203, the power trans-
sequence program(PCM) states:
of former, and power transistors for the power supply are
mounted on the rear panel of the instrument. Other power
a. Signal Integration (KM-A). The integrator capaci- supply components are mounted on the Logic and Inter-
tor chargesto a voltage proportional to the input connection assembly. Also mounted on the rear panel, in
voltage during a 20 msecsamplingperiod. addition to .I201 and 1202, is the rear INPUT connector
J204, the ANALOG OUTPUT connector and common, the
b. ReferenceIntegrate (KM-C). During this period, EXTernal REFerenceconnector and common, and the line
the integrator capacitor discharges a constant cur-
at fuse F201,
rent. The time that the integrator requires to dis-
charge(full discharge detected by the Null Detector) 1.31 A dimensional outline of the Model 5900 is shown
is measuredby the counter. The data in the counter in tigure 1.2.
at the end of PCM.C is proportional to the input
voltage.
c. Strobe @CM-D). At this time, data in the counter
is strobed into the storagelatches and displayed -
the print pulse is inhibited, however if an uprange
or downrange command is generatedby the Auto-
range logic. If a range change is required, the
counter is reset and the program returns to PGM-A.
d. Reset @`CM-E). At PCM-E,all internal logic is reset
in preparation for the next reading.
1.24 An additional control state, PGM.B, occurs after
PGM-A and is a delay to allow for propagation time of the
counter.
1.25 The Control/Display section generatesthe control
signals necessary to operate the signal conditioning and
integrating circuits.
1.26 MECHANICAL DESCRIPTION.
1.21 The ohms measurementoption consists of a single
printed-circuit board. The AC options both consist of two Figure 1.2 Dimensions
boards. The accessoryboards plus the Digitizer, Isolator,
and Function Switching board all plug into the Main Logic 1.32 SPECIFICATIONS.
board called the Logic and Interconnection assembly. This
board also carriesmuch of the instrument logic. 1.33 Specificationsare listed in table 1.2.
1-3
980453 Table 1.2 - Specifications
SPECIFICATIONS, MODEL SSOO
AS A DC VOLTMETER IBASIC INSTRUMENTl
RATIO tdcldc. mVldc. acldc)
SPECIFICATIONS CONTINUED NEXT PAOE
Table 1.2 -Specifications (continued) 980453
l-5
SECTION 2 INSTALLATION & OPERATION
2.1 UNPACKING AND INSPECTION.
2.2 The Model 5900 DMM is packed in a molded
plastic-foam form within a cardboard carton for shipment.
The plastic form holds the DMM securelyin the carton and
absorbsany reasonable external shocknormally encountered
in transit. Prior to unpacking, examine the exterior of the
shipping carton for any signsof damage.Carefully remove
the DMM from the carton and inspect the exterior of the
instrument for any signs of damage. If damageis found,
notify the carrier immediately.
2.3 Included with the instrument in the packing con-
tainer are the instruction manual, power cord, and rear in-
put and BCD output mating connectors. With instruments
equipped with remote programming, a mating connector
for that accessory included.
is
2.4 BENCH OPERATION.
2.5 Each Model 5900 is equipped with a tilt bail or
"kickstand" to enable the front of the instrument to be
elevated for convenient bench use. The tilt bail is attached
to the two front supporting "feet" at the bottom of the
instrument. For use, the bail is pulled down to its sup-
porting position.
2.6 RACK MOUNTING.
2.1 The instrument can be mounted in a standard 19. 2.6 POWER CONNECTIONS.
inch rack with the optional rack-mounting flanges(403402,
includes attaching hardware). To install the flanges, pro- 2.9 Standard units operate on either 1IS volts or 230
ceedas follows: volts, SOto 60 Hz (400 Hz available). Power consumption
is less than 40 watts. Operation on either of the two line
a. With instrument on its side, remove four Phillips- voltages is selectableby a slide switch on the rear panel.
head screwsholding bottom cover. Remove cover. Operation on lOO/ZOO volts or 1201240volts is possibleby
Remove screwsholding feet (and bail) in place. Re- simple rewiring of the power transformer secondary wires:
place bottom cover. WARNING
Disconnect the instrument from the AC Power source
b. Place one of the supplied screws through each of before attempting to change power connections.
the two holes in the mounting flange (figure 2.1). Potentially lethal voltages are exposed when covers
Thread a securingnut onto each screwjust enough are removed.
to attach it to the screw(approximately one turn).
a. For operation on 100/200 volts, cut the brown wire
c. Place the mounting flange onto the mounting slot 1" from the transformer and splice it to the red
in the instrument side panel so that the securing wire on the transformer; cut the blue wire 1" from
nuts fit entirely into the slot. Be sure the rack- the transformer and splice it to the violet wire.
mount slots on the flange are toward the front of
the instrument. b. For operation on 120/240 volts, cut the brown
wire 1" from the transformer and splice it to the
d. Tighten screws. The securing nuts will rotate and black wire; cut the blue wire and splice it to the
hold the flange securelyin place. yellow wire on the transformer.
2-I
980453
2.10 A standard power cable having a three-pin plug is panel binding posts. The rear-panelinput lines are wired in
supplied with the instrument. It connects to POWERcon. parallel with the front-panel input lines. It is recommended
nectar 5203. The ground pin (round) is attached to the that the cable for the mating connector be constructed as
instrument case. It is important that this pin be connected shown in figure 2.3 using two two-conductor shielded
to a good quality earth ground. cables. Other configurations may be desirable depending
on the ohms measuring method to be used (see para-
2.1 I Fuse receptacleF20l on the rear panel is equipped graph 2.28).
with a .5 amp fuse in domestic units.
2.12 INPUT/OUTPUT CABLING.
2.13 Binding Posts.
2.14 Several connectors on the Model 5900 consist of a
pair of binding posts spaced so as to accept standard
"banana" plugs. The connectorsare:
I Front Panel I Rear Panel I
+ INPUT f. ANALOG OUTPUT
+ OHMS CURRENT ?1REFerenceINput
2.15 Input cables to fit this type of connector can be
ordered from Keithley (P/N 5900-402190). Figure 2.2 is a
wiring diagram of this cable included for assistance users
to 2.18 MANUAL OPERATION.
desiring to construct their own cables.
2.19 Controls.
2.20 All operating controls are located on the front panel
of the instrument. They are shown in figure 2.5 and their
operation described in table 2.1. Description of Systems
operation beginsin paragraph2.44.
2.21 DISPLAY.
2.22 The Pisplay consists of 6 LED decimal readout
devices with moving decimal point. The decimal point
movesin conjunction with the rangeswitchor automatically
in auto range. Maximum usable readout with overrangeis
159999. Overload is indicated by a NO and 160000 read-
out. A non-compatible range and function is indicated by
a NO. However, mechanicalinterlocks are provided to pre-
vent illegal combinations from the front panel. Figure 2.4
illustrates the readout, NO indicator, polarity sign and the
2.16 Rear Input Connector.
DC MO
2.17 Instruments equipped with the -I or -IS rear input + r /--- r-7 ,---I ,---I ,--1 AC KO
option are supplied with 5204 7.pin input connector - I L-, L-4 L-4 L-,' L-4 PGM n
(Keithley P/N 5900-600673) and a mating connector NO,' --J. ,' : : :
FIL R
(Keithley P/N 5900-600616). The instrument acceptsinputs
applied to this connector or inputs applied to the front- Fiwe 2.4 . Readout
2-2
Figure 2.5 -Front Panel
Table 2.1 . Operating Controls
Control Position Function
POW1 ON (UP) Applies power to instrument
(rocker switch)
OFF (down) Removes
power from instrument
Function Select ACT Selectsthe measurement AC voltageson the I, IO, 100, and
of
(rotary switch) 1000 volt ranges(max. input, 1OOOV
RMS)
DC Selectsthe measurement DC voltageson the .l, 1, IO, 100,
of
and 1000 volt ranges(max. input, IlOOV)
Selectsthe measurement resistanceon the 10 ohm range;on
of
the.1,1,10,100,andlOOOkilohmsranges;oronthe10or100
Megohmranges
RangeSelect AUTO SelectsAuto Rangein which the optimum rangeis selectedauto-
(rotary switch) matically by internal circuits. Uprangeoccurs at 160%of full
scale;downrangeoccursat 15%of full scale
Other Positions Enablesmanual selection of fiied ranges. Rangespermissiblefor
eachfunction are inscribed on the parlel
DATA OUTPUT Depressed ,Enablesthe print pulse causingBCD data at P201 to be recorded
(pushbutton) by printer, or other output device. (Output data is presentat
P201 regardless the position of this switch.)
of
PROGRAMCONTROL Depressed Enablesthe selection of range,function, and mode to be made
(pushbutton) externally through the remote programmingconnector and dis.
ablesall front panel controls (requires programmingoption)
RATIO Depressed Selectsa ratio measurement which the readout representsthe
in
(pushbutton) ratio of the input to an external d-c referencevoltage (applied at
terminals on the rear panel) multiplied by 10: Ein/ERafx 10
FILTER Depressed Adds an active four.pole filter acrossthe input circuit
(pushbutton)
RATE EXT (ccw) Selectsthe Hold mode. A new readingis initiated through the
(pot) remote program input
cw Increaseperiodic read rate to a maximum of four readings/second
FRONT/REAR FRONT Connectsfront panel data input terminals to instrument
(slide switch)
REAR Connectsrear panel data input terminals to instrument
*NOTE: Ohms input terminals are open in AC or DC function.
TNOTE: For inputs greaterthan lSOV, Filter should be "IN".
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2.23 MEASUREMENT CONNECTIONS. achieved by `placing a shorting bar between - INPUT and
GUARD and shorting the singlebananaplug (shield) to the
- INPUT side of the double bananaplug at the input con-
NOTE
nector. This arrangementis adequatefor measuringall but
Before taking any measurements, refer,to the list of low voltage (mV) levels and/or in high-noiseenvironments.
maximum input voltages,table 2.2.
2.27 Whenmaking "floating"voltage measurements(both
measurementpoints above ground potential), do not con-
nect GUARD to measurementground without making sure
Table 2.2 - hlaximum Input Voltage
that the voltage between GUARD and - INPUT does not
exceed250 volts.
CAUTION
Do not exceedthe following maximum inputs: Y`RMS
DC 1lOOVDCor 1OOOVRMSAC
AC 1OOOV RMS decreasihg 20V RMS at
to
1 MHz (seefigure 2.7)
n +SOOV peak between+I and -I(lOOOV
RMS if in DC or AC function.)
RATIO Input: sameas function selected
Reference: +lO.SV, -0.5V
GUARD Voltage betweenGUARD and - INPUl
must not exceed250 volts or damage
to the instrument may result
2.24 Basic Voltage Measurement.
2.25 An ac or dc voltage measurementconnection rec-
ommended to minimize the effects of noise requiresa two-
conductor shielded cable connected as shown in figure 2.6.
t 2.28 Ohms Measurement.
2.29 Ohms measurementin the Model 5900 consistsof
the application of a known current through the unknown
resistance(Rx) and measuringthe ratio of the voltage drop
acrossRx to the drop acrossan internal "full-scale" resistor
(Eh/EFS). Current through Rx is applied through leads
from the f. OHMS CURRENT terminals. The voltage drop
is sensed the + INPUT terminals.
by
2.30 TWO.WIREMEASUREMENTS.
Figure 2.6. Basic Voltage Measurement Connections
2.31 Connections for a simple two-wire shielded ohms
2.26 For all voltage measurements, GUARD lead arId
the measurement shown in figure 2.8a. It consistssimply of
are
the - INPUT lead are connectedto the measurement
point a single-conductorshieldedcable with the conductor serving
nearest ground potential. Somewhat less shielding is as both the t CURRENT and + INPUT leadsand the shield
2.4
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(4
(b)
lNP"T
CVRRENT
RX
Figure 2.8 - Two Wire Ohms Measurements
2-s
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Figure 2.9 - Four Wire Ohms Measurement
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carrying - CURRENT and - INPUT. While reasonably 2.36 This configuration, although shielded, places the
accurate measurementscan be made with this method, shield capacitance and cable leakage in parallel with Rx.
shunt leakage problems result from the parallel combinations This results in loss of accuracy and slow measurements.In
of Rx and the cable impedance. This causes of accuracy,
loss addition, it is very responsiveto the triboelectric effect at
especially at high resistance(100 Ma range). Also, lead high resistancemeasurements.
resistancebecomesa factor in the 10 and 100 ohms ranges;
the four wire measurement system is recommended for 2.39 Better guarding is achieved by the use of the con-
theseranges. figuration shown in figure 2.9b. Here again,RG196U teflon
dielectric cable (either single-conductor shielded or two-
2.32 A more accurate two-wire measurementconnection conductor shielded) is used on the positive terminals. The
is shown in figure 2.6b. The + INPUT and + CURRENT, shield(s) are connected to Ohms Guard (low ANALOG
- INPUT and - CURRENT terminals are again tied to- OUTPUT terminal). The negativeleadsare single wires with
gether. But now, the positive side is a single-conductor, the - INPUT terminal tied to GUARD.
shielded cable with the shield tied to Ohms Guard. Ohms
Guard is the low ANALOG OUTPUT terminal on the rear 2.40 This eliminates much of the shunt leakageproblem
panelof the Model 5900 when ohmsis selected.The negative of the previous configuration sinceguard current now flows
side is a single wire connected as shown. Guard current is through the low side of the measurement circuit. Measure-
present in the low side, but the leakageproblems of the ment is much faster since the shield capacity is driven by
first configuration are eliminated. the guard current.
2.33 In high noise-levelenvironments, the configuration 2.41 A high-noise environment calls for the "super"
shown in figure 2.8~ is recommended. This method also configuration shown in figure 2.9~. Here, a two-conductor,
eliminates error due to shunt leakage,but provides more double-shieldedcable is usedas the positive leads. The inner
complete shielding. The positive terminals are tied together shield is tied to Ohms Guard. A twoanductor shielded
andcarried in a single-conductor,double-shieldedcablewith cable is used as the negative leads. Its shield is tied to
the inner shield tied to OhmsGuard(-ANALOG OUTPUT). GUARD and to the outer shield of the positive cable. The
The outer shield is tied to GUARD. The negativeterminals shieldis alsotied to CURRENTat the measurement point.
are tied together and carried in a single-conductorshielded This configuration maintains high guarding characteristics
cable with the shield tied to GUARD. This configuration while eliminating guard current sensitivity.
eliminates guard current sensitivity, thereby increasing
guarding characteristics. 2.42 Ratio Measurements.
2.43 Ratio measurements madeby applying a positive
are
d-c voltageto the referenceinput terminals on the rear panel
2.34 FOUR-WIREMEASUREMENTS and an input signal of any function at the front input
terminals. For DC/DC or AC/DC ratios, the reference
2.35 In most system applications, the device to be meas- voltage must be within the rangeof +IV to +lO.SV. Input
ured is locatedat Bremotelocation requiring interconnection signal limitations (numerator) are the sameas tbosc given
by cables of lengths from several to possibly hundreds of for conventional measurementof the particular function
feet. Whenmeasuringlow resistance valuesover long cables, (table 2.2). The readout is the ratio multiplied by ten:
most lead resistanceproblems can be solvedby the useof a Einput/Ereference x 10. In the standard instrument the
four-wire measurement system. INPUT terminal is internally connected to the REF in-
put terminal; in instruments equipped with the option 62
2.36 For high resistancemeasurements over long cables, 4-wire ratio, both reference inputs arc floating (IO Ma
other problems are encountered: noise pick-up, leakage between- REF and -SIGNAL).
resistance, and capacitive loading of the system. These
problems can be minimized by proper shielding and the use
of ohms guard. 2.44 SYSTEM CAPABILITIES.
2.37 Figure 2.9a shows a basic shielded four-wire ohms 2.45 The 5900 has two systeminterface connectorsdesig-
measurementconfiguration. This method usestwo single- nated as 3201 (PRINTER OUTPUT) and 5202 (PROGRAM
conductor shielded teflon cables. The conductors carry the INPUT) mounted on the rear panel of the instrument (fig
positive sidesof the INPUT and CURRENT lines while each ure 2.10). The following is a brief description of the capa-
shield carriesthe low side. bilities of eachconnector.
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2.46 Printer Output - 5201. other words, the complement of X is x. The truth table
shows that the two signals X and x, are by definition, in
2.47 Through this connector the 5900 supplies BCD opposite logic states(seetable 2.3).
representations of the decimal display; various flags or
indicators of the mode of operation, function and range;
Table 2.3 - PositiveTrue Logic Relationships
and a print command. Provision has alsobeen madefor 60
Hz instruments to accept a fast (20 readings per second
maximum) or a superfast(I 01 readingsper secondminimum) Voltage Level of Voltage Level of
read command. In 50 Hz units, the fast command obtains Signal Logic State Output Line "x" Output Line "p
I7 readings per second,minimum, and the superfast com-
mand 93 readingsper second. "X" True or "1" 2.4 - 5.0 Volts 0.0.0.4
Falseor "0" 1 0.0-0.4 Volts 1 2.4.5.0
2.48 Program Input. 2.53 As seenabove, if gate A has a true or "1" level on
output X, its voltage level is the most positive of the two
2.49 Through this connector the 5900 receivesexternally ranges present, and output x must be in a false or "0"
generatedsignals that select the function, range, mode of state with the lowest or most negativevoltage rangepresent.
operation, and initiate the read commands. The reversewould be true for a falseor "0" level on output
X.
2.54 Driving the Inputs.
2.50 LOGIC LEVELS AND ELECTRONIC IN-
TERFACE. 2.55 All inputs are TTL compatible and most are the
equivalent of one 7400 series TTL input with a pull-up
2.5 1 TTL-compatible positive-true logic levels are used resistor for contact closure operation.
in the 5900. In some instances,however, complementary
signalsare used. These terms are more specifically defined
below:
Signalsand Their Complements-
0
2.56 TTL Loading Conditions,
2.57 To input a "I" level the pull.up resistor will supply
2.52 If the non-inverting output of gate A is defined as the necessarysource current (40 /.tA) to maintain the mini-
signal X, then it follows that the inverting output is ???;
in mum 2.4 volts. In fact, the pull-up resistor will maintain a
Figure 2. IO - Rear Panel
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Figure 2.11 Measurement Sequence
2-9
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one level as long as the input source resistance(RI) to 2.62 Timing Sequence.
ground is greaterthan ISK ohms.
2.63 The standardremote mode of operation of the 5900
is to initiate a readingsequence