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175_AV_901_01C


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  Model 175AV
Autoranging
          Multimeter
   Instruction Manual




                        Contains Operating and Servicing Information
                                                     WARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year
from date of shipment.


Keithley Instmments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable
batteries, diskettes, and documentation.


During the warranty period, we will, at our' option, either repair or replace any product that proves to be defective


To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio.
You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service
facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for
the balance of the original warranty period, 01 at least 90 days.



                                           LIMITATION OF WARRANTY
This warranty does not apply to defects resulting from product modification without Keithley's express written consent, or
misuse of any product 01 part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from
battery leakage, 01 problems arising from normal wear or failure to follow instructions.


THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY
IMPLIED WARRANTY OF MERCHANTABILITY    OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PRO-
VIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE REMEDIES.


NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ll?i EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT,
INDIRECT. SPECIAL. INCIDENTAL  OR CONSEOUENTIAL     DAMAGES ARISING OUT OF THE USE OF ITS
INSTRUMENTS AND'SOFTWARE EVEN IF KEIT%tiY    INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE
OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIM-
ITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY
PERSON, OR DAMAGE TO PROPERTY.
Model 175-AV Autoranging Multimeter
         Instruction Manual




           01989, Keithley Instruments, Inc.
                  All rights reserved.
               Cleveland, Ohio, U.S.A.
             Third Printing, October 1999
       Document Number: 175.AV-901-01 Rev. C
                                    Manual Print History

  The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The Revi-
sion Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released
between Revisions, contain important change information that the user should incorporate immediately into the manual.
Addenda am numbered sequentially. When a new Revision is created, all Addenda associated with the previous Revision
of the manual are incorporated into the new Revision of the manual. Each new Revision includes a revised copy of this
print history page.


            Revision B (DocumentNumber IX-AV-901-01) ...............................................................................
                                                                                                                              Odoer 1992
            Revision C (OaeumentNumber 175.AV-901-01)...............................................................................
                                                                                                                              October 1999
                               SAFETY PRECAUTIONS
The following     safety precautions    should be observed before operating the Model 175-AV.


This instrument is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety
precautions required to avoid possible injury. Read over 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 hazard exists when voltage levels greater than 3lV 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.


Inspect the test leads for possible wear, cracks or breaks before each use. If any defects are found, replace the test leads.


Foroptimumsafetydonottouchthetestleadsortheinstnunentwhilepowerisappliedtothecircuitundertest.Turnthe
power off and discharge all capacitors before connecting or disconnecting the instrument.


Do not touch any object that could provide a current path to the common side of the circuit under test or power line
(earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface, capable of with-
standing the voltage being measured.


Exercise extreme safety when testing high energy power circuits (ac line or mains, etc.). Refer to High Energy Circuit
Safety Precautions found in paragraph 2.2.


Do not exceed the instrument's         maximum   allowable   input as defined in the specifications     and operation section.


Instrumentation     and accessories should not be connected to humans.
                                                                          Safety Precautions

The following safety precautions should be observed before using           Users of this product must be protected from electric shock at all
this product and any associated instrumentation. Although some in-         times. The responsible body must ensure that users .a.= prevented
struments and accessories would normally be used with non-haz-             access and/or insulated from every connection point. In some cases,
ardous voltages, there are situations where hazardous conditions           connections must be exposed to potential human contact. Product
may be present.                                                            users in these circumstances must be trained to protect themselves
                                                                           from the risk of electric shock. If the circuit is capable of operating
This product is intended for use by qualified personnel who recog-         at or above 1000 volts, no conductive      part of the circuit may he
nix shock hazards and are familiar with the safety precautions re-         exposed.
quired to avoid possible injury. Read the operating information
carefully before using the product.                                        As described in the International Elcctrotechnical Commission
                                                                           @EC) Standard IEC 664, digital multimeter measuring circuits
The types of product users are:
                                                                           (e.g., Keithley Models l75A, 199,2000,2001, ZWZ, and 2010) are
Responsible body is the individual or group responsible for the use        Installation Category II. All other instruments signal terminals are
and maintenance of equipment, for ensuring that the equipment is           Installation Category I and must not he connected to mains.
operated within its specifications and operating limits, and for en-
suring that operators are adequately trained.                              Do not connect switching cards directly to unlimited power circuits.
                                                                           They are intended to he used with impedance limited sources.
Operators use the product for its intended function. They must he          NEVER connect switching cards directly to AC mains. When con-
trained in electrical safety procedures and proper use of the instm-       necting sources to switching cards, install protective devices to lim-
meat. They must be protected from electric shock and contact with          it fault current and voltage to the card.
hazardous live circuits.
                                                                           Before operating an instrument, make sure the line cord is connect-
Maintenance      personnel perform routine procedures on the product       ed to a properly grounded power receptacle. Inspect the connecting
to keep it operating, for example, setting the line voltage or replac-     cables, tat leads, and jumpers for possible wear, cracks, or breaks
ing consumable materials. Maintenance procedures are described in          before each use.
the manual. The pmcedures explicitly state if the operator may per-
form them. Otbenvise. they should be performed only by service             For ma.ximum safety, do not touch the pmduct, test cables, or any
personnel.                                                                 other instruments while power is applied to the circuit under test.
                                                                           ALWAYS remove power from the entire test system and discharge
Service personnel are trained to work on live circuits, and perform        any capacitors before: connecting or disconnecting cables or jump-
safe installations and repairs of products. Only properly trained ser.     ers, installing or removing switching cards, or making internal
vice personnel may perform installation and service procedures.            changes, such as installing or removing jumpers.

Exercise extreme caution when a shock hazard is present. Lethal            Do not touch any object that could provide a current path to the
voltage may be present on cable connector jacks or test fixtures. The      common side of the circuit under test or power line (earth) ground.
American National Standards Institute (ANSI) states that a shock           Always make measurements with dry hands while standing on a
hazard exists when voltage levels greater than 30V RMS, 42.4V              dry, insulated surface capable of withstanding the voltage being
peak, or 60VDC are present. A good safety practice is to expect            measured.
that hazardous     voltage is present in any unknown   circuit   before
measuring.
The instrument and accessories must be used in accordance with its       The WARNING heading in a manual explains dangers that might
specifications and operating instructions or the safety of the equip-    result in personal injury or death. Always read the associated infor-
ment may be impaired.                                                    mation very carefully before performing the indicated procedure.

Do not exceed the maximum signal levels of the instruments and ac-       The CAUTION heading in a manual explains hazards that could
cessories, as defined in the specifications and operating informa-       damage the instrument. Such damage may invalidate the warranty.
tion, and as shown on the instrument or test fixture panels, or
switching card.                                                          Instrumentation and accessories shall not be connected to humans.

When fuses are used in a product, replace with same type and rating      Before performing any maintenance, disconnect the line cord and
for continued protection against tire hazard.                            all test cables.
                                                                         To maintain protection from electric shock and fire, replacement
Chassis connections must only be used as shield connections for
                                                                         components in mains circuits, including the power transformer, test
measuring circuits, N(rT as safety earth ground connections.
                                                                         leads, and input jacks, must be purchased fmm Keithley Instrw
                                                                         meres. Standard fuses, with applicable national safety approvals,
If you ax using a test fixture, keep the lid closed while power is ap-
                                                                         may be used if the rating and type are the same. Other components
plied to the device under test. Safe operation requires the use of a
                                                                         that are not safety related may be purchased from other suppliers as
lid interlock.
                                                                         long as they are equivalent to the original component. (Note that se-
                                                                         lected parts should be purchased only thmugh Keithley Instruments
If a @screw is present, connect it to safety earth ground using the
                                                                         to maintain accuracy and functionality of the product.) If you are
wire recommended in the wer documentation.
                                                                         unsure about the applicability of a replacement component, call a
                                                                         Keithley lnshuments office for information.
The .A! symbol on an instrument indicates that the user should re-
fer to the operating inshlctions located in the manual.
                                                                         To clean an instrument, use a damp cloth or mild, water based
                                                                         cleaner. Clean the exterior of the instrument only. Do not apply
The A     symbol on an instrument shows that it can source or mea-
                                                                         cleaner directly to the instrument or allow liquids to enter or spill
sure 1000 volts or more, including the combined effect of normal
                                                                         on the instrument. Pmducts that consist of a circuit board with no
and common mode voltages. Use standard safety pncautions m
                                                                         case or chassis (e.g., data acquisition board for installation into B
avoid personal contact with these voltages.
                                                                         computer) should never require cleaning if handled according to in-
                                                                         structions. If the board becomes contaminated and operation is af-
                                                                         fected, the board should be remmed to the factory for pmper
                                                                         cleaning/sewicing.




                                                                                                                                    Rev. lo/99
                                  MODEL 175-AV SPECIFICATIONS
DC VOLTS                                                                                                          ACCURACY Year)
                                                                                                                         (1
                                                                                                   *v-zBT
                RANGE                           RESOLUTlON                                    ti%rdS + counts)
                 2M) mV                                      10 uv                                     0.03 + 3



                  XQV                                100 mV                       o.B3+2
                  rTANcEz         IlMG   on 2M:Imy, ZV, and 2~~o~;Ses. l0Mi-I on ZOOV and 1ooOVra"Ses. (>lOCOMGon the 2OOmVand 2V
                                                                        HIHZ, 6OHz M.lS%.
                                                                       +&C (lZOdB at DC, 5OHz, 6OHz ti.15%. %OdB in AC volts.
TEMpERAm@         comam            (o"-i80c 6r 2.5~~c): no.1 x applicsble accurav S@fiCatiOn)/oc     except +:(O.O7%+2)/"C
    for 5OHz-1OkHz in AC volts.
E~JR~&Operathg:                 00 to SOT; 40% relative humidity up to 35'C; linearly date 3% RH/`C, 35' to 5WC. Storage
POWERz lQ5-125V or 210-250" @&rnal switch selened), 5L?-6OHz,12VA. Optional &hour battery pack, Model 1758.
DIMBN?ONS, WEIGIiTz B9mm high x 235mm wide x 275mm deep (3.5 in. x 9.25 in. x 10.75 in.). Net weight l.Skg (3 Rx., 14
    oz.,.
ACCESSORIES SUPPLIED: Model 1751 Safety Test Leads, instruction manuals (2).
 A,.C~CC~.,.rm n
`.~~#aU""R~T~      ..r... 1W.E.
       Model 1010:
       Model 1017:          I RackMointl.~ `kit
       Model 1501:          peruhuePi-oh.2-WC to +lMTl
                                          $
       Model l&WA:          ~Voltag~.Pmbe WkVl
       Model 1651:
       Model 1681:
       y≤ ygAz
    Model   16&                                    A)
    Model   1751;
    Model   17!i5-A                 ,.-__
    pde;    ;75$                    t Lead Kit
    Model 17Si
    Model 7008-3:                                   (3 ft.)
    t$3del7cm.6                                    I 0i ft.)
                                                Table of Contents
SECTION 1 - General Information
1.1      INTRODUClTON         .................                                                          ......................                        l-l
1.2      FEATURRS ......................                                                                 ......................                        l-l
1.3      WARRANTY INFORMATION                         .......                                            ......................                        l-1
1.4      MANUAL ADDENDA                 .............                                                    ......................                        l-l
1.5      s~sYMBo~ANDTERMs                                  .....                                         ......................                        1-l
1.6      SPBCIFICATIONS          ................                                                        ......................                        l-2
1.7      INSPECTION    ....................                                                              ......................                        l-2
1.8      USING TI-IE MODEL 175-AV MANUAL                                                                 ......................                        1-2
1.9      GETTING STARTED ..............                                                                  ......................                        l-2
1.10     ACCESsORIES ...................                                                                 ......................                        1-3


SECTION 2 - Bench Operation
2.1      INTRODUCTION             ..........................                                                                        ........           2-l
2.2      HIGH ENERGY CIRCUIT SAFETY PRECAUTIONS                                                                                     ........       .   2-l
2.3      PRBPARATION FOR USE ...................                                                                                    ........       .   2-l
2.3.1      LinePower      ..............................                                                                                 .......   .   2-l
2.3.2      Battery Pack Power ........................                                                                                   .......   .   2-2
2.3.3      Battery Charging. .........................                                                                                   .......   .   2-2
2.4      FRONTPANELF            AMLMREA'ITON                           ............                                                      .......   .   2-2
2.4.1      Display .................................                                                                                     .......       2-3
2.4.2      Front Panel Controls .......................                                                                                            .   2-3
2.4.3      InputTerminals           ..........................                                                                      ........           2-3
2.4.4      AMPS Fuse Replacement                     ...................                                                            ........       .   23
2.5      ERROR MESSAGES .........................                                                                  ......           ........           2-4
2.6      OPERATING CONDITIONS                           ..................                                         ......           ........       .   24
2.6.1      Fnvironmental        conditions              ..................                                                                         .   2-4
2.6.2      Maximum Allowable Inputs .................                                                       ..........            .........        .   2-4
2.7      BASIC BENCH MEASUREMENX                                  ..............                            ..........            .........        .   2-4
2.7.1      Power-Up..        .............................                                                  ..........            .........        .   25
2.7.2      RelativeMode        ............................                                                 ..........            .........        .   2-5
2.7.3      Dc Voltage Meaanremenls ...................                                                                            .........        .   2-6
2.7.4      Average AC Voltage Measurements ............                                                                                            .   2-6
2.7.5      Resiitance Measurements ...................                                                                                             .   2-7
2.7.6      Current Measurements (dc or average ac) .......                                                                                         .   2-7
2.7.7       dB Measurements .........................                                         ........................                             .   2-8
2.7.8       dB Measurement Considerations and Applications                                    ........................                             .   2-10
2.7.9       m/MAX         and lOO-Point Data Logger Operation .                               ........................                                 2-11
2.7.10      DiodeTest     ..............................                                      ........................                                 2-11
2.8       AVERAGE RESPONDING MEASUREMENTS                                           . ., ..   ........................                             .   2-11
2.8.1       Waveform Comparison .....................                                         ........................                             .   2-12
2.8.2       Ac Voltage Offset .........................                                       ........................                                 2-14
2.8.3        Extended Frequency Response                          ..................................................           2-14


SECTION 3 - Performance Verification
3.1       INTRODUCTION           .............................................................                                 3-l
3.2      ENVIRONM-ENTALCONDlTIONS..                                   ..............................................           3-l
3.3      INITIAL CONDITIONS                .........................................................                           3-l
3.4      RECOh4MBNDED TEST EQUIFMENT                                   ...............................................         3-l
3.5      VERIFICATION       PROCEDURE                   ....................................................                   3-l
3.5.1       DcVoltageVerification             ........................................................                         3-l
3.5.2       ,Average Ac Voltage Verification                   .................................................               3-2
3.5.3        Resistance Verification          ........................................................                         3-3
3.5.4        DC Current Verification ........................................................                                  3-3
3.5.5        AverageAcCurrentVerification                      .................................................               3-3
3.5.6        Diode Test Current Verification ..................................................                                3-3


SECTION 4 - Principles of Operation
4.1      INTRODUCTION             .............................................................                                41
4.2      OVERALLFUNCTlONALDESCRIPTION..                                            .........................................   4-l
4.3      ANALOGC~~Y                      ..........................................................                            4-2
4.3.1      Multiplexer.   ................................................................                                     42
4.3.2      InputBufferAmplifier                ........................................................                        4-2
4.3.3      -2V Reference Source             .........................................................                          42
4.3.4      A/DConverter        ..............................................................                                  43
4.3.5      InputsignalConditio~g                    ......................................................                     4-4
4.3.6      Ac Converter      ...............................................................                                   4-5
4.4      DIGITAL CIRCUITRY                ..........................................................                           45
4.4.1      Microcomputer        ..............................................................                                 45
4.4.2      AddressDecoding           ...........................................................                               4-6
4.4.3      Pu ......   : ................................................................                                      4-6
4.4.4      Display Board ...............................................................                                       4-6
4.5      DIGlTAL CALIBRATION                ........................................................                           44
4.6      POWERSUPPLY          ..............................................................                                   4-6
4.7      MODEL1758BATTERYOpTION                            ..................................................                  4-6


SECTION 5 - Maintenance
5.1       INTRODUCTION.            .............................................................                               5-l
5.2       LINBVOLTAGESELECTION                           ....................................................                  5-l
5.3       FUSEREPLACBMENI                 ..........................................................                           5-l
5.3.1        AMpsFuSe .................................................................                                        5-2
5.3.2        Line Fuse ..................................................................                                      5-2
5.4       CALIBR4TION         ...............................................................                                  5-2
5.4.1        RecommendedCaIibrationEquipment                                 ............................................      5-3
5.4.2        Environmental Conditions                  .....................................................                   5-3
 5.4.3       Warm-UD Period ............................................................                                       5-3
5.4.4      CALIBRATION Switch.. .................................................................................................................................                 5-3
54.5       DC Voltage Calibration From Front Panel.. ..................................................................................................                           5-3
54.6       AC Voltage Calibration From Front Panel.. ..................................................................................................                           5-4
5.4.7      Resistance Calibration From Front Panel ....................................................................................................                           54
5.4.8      Frequency Compensation ..............................................................................................................................                  5-5
5.4.9      Calibration Storage .........................................................................................................................................          5-5
5.4.10     IEEE-488 Bus Calibration ...............................................................................................................................               5-5
5.5      SPECIAL HANDLING         OF STATIC SENSITIVE DEVICES.. ........................................................................                                          5-6
5.6      TROUBLESHOOTING         .......................................................................................................................................          S-6
5.6.1      Recommended Test Equipment ....................................................................................................................                        S-6
5.6.2      Self Diagnostic Program.. ...............................................................................................................................              5-7
5.6.3      Power Supply and Battery Pack (Model 1758) Checks.. ............................................................................                                       5-11
5.6.4      A/D Converter and Display ..........................................................................................................................                   5-11
5.6.5      Signal Conditioning.. ......................................................................................................................................           5-11
5.7      MODEL 1758 BATTERY PACK INSTALLATION                                   AND REMOVAL ..........................................................                            5-13
5.8      BATTERY PACK STORAGE.. ............................................................................................................................                      5-13


SECTION 6 - Replaceable Parts
6.1      INTRODUCTION          ...............................................................................................................................................    6-l
6.2      PARTS LIST.. ........................................................................................................................................................    6-l
6.3      ORDERING INFORMATION                       ...........................................................................................................................   6-l
6.4      FACTORY SERVICE ...........................................................................................................................................              6-l
                                           List of Illustrations
SECTION 2 -         Bench       Operation

Figure   2-I    Model 175-AV Front Panel ..................................                                                                2-2
Figure   Z-2    dc Voltage Measurements ...................................                                                                2-6
Figure   2-3    ac Voltage Measurements       ...................................                                                          2-7
Figure   2-4    ResistanceMeasurements..           . . ...............................                                                     2-7
Figure   2-5    CurrentMeasurements      .....................................                                                             2-8
Figure   2-6    Model 1%AV Typical acV Frequency Response ..................                                                               2-15


SECTION 4 - Principles of Operation
Figure   41     SimplifiedBlodcDiagram     ........................................                                                        41
Figure   42     Simplified Schematic of the Multiplexer              .............................                                         42
Figure   43     Simplified Schematic of the Input Buffer Amplifier                       .....................                             42
Figure   44     Simplified Schematic of the A/D Converter                    ..........................                                    4-3
Figure   45     Resistance Measurements - Ratiometric Technique                            ....................                            4-4
Figure   46     Simplified Schematics of Ohms Circuitry.                ............................                                       4-5


SECTION 5 - Maintenance
Figure 5-1      Model 175-AV Rear Panel ................                                          .               ......................   5-1
Figure 5-2      Segment Identification ..................                                         ...             ......................   5-7


SECTION 6 - Replaceable Parts
Figure   6-l    Model 175-AV/I758     ....................                                           .    .     ......................     6-3
Figure   62     Model 175-AV Final Assembly ............                                          ...       . ......................       65
Figure   6-3    Front Panel Assembly ...................                                             .      . ......................       6-7
Figure   6-4    Connector Assembly ....................                                           ...     .     ......................     6-9
Figure   W      Mother Board Component Layout (sheet 1 of 2)                                       ..           ......................     6-15
                Mother Board Component Layout (sheet 2 of 2)                                       ..           ......................     6-17
Figure 6-6      Mother Board Schematic (sheet 1 of 2) .......                                     . .       . ......................       6-19
                Mother Board Schematic (sheet 2 of 2) .......                                      ..       . ......................       6-21
Figure   67     Display Board Subassembly ..............                                          . .           ......................     6-25
Figure   6-8    Display Board Schematic ................                                          ...           ......................     6-27
Figure   69     Model 1758 Battery Option ...............                                         ...     . . ......................       6-29
Figure   6-10   Battery Option Component Layout .........                                         ..      . . ......................       6-33
Figure   611    Battery Option Schematic ................                                         ..      . .......................        6-35
Figure   6-12   Battery Assembly ......................                                                   . . .......................      6-37
                                                        List of Tables
SECTION 2 - Bench Operation
Table   2-1   EmrMsaagas             ...................................                           ..............   2-4
Table   2-2   Model 17~AV Maximum Allowable Inputs            .............                      ...............    2-5
Table   2-3   dB Spedfications for dc Volts (6CGR R4.    ...............                                            2-8
Table   24    dBSpecificationsforacVolts~MxIRRef)     ................                                              2-8
Table   2-5   Lewis for Other Reference Jmpedances .................                              ..............    2-9
Table   2-6   Average Responding Meter Readings for Various Waveforms                             ..............    2-13


SECTION 3 - Performance Verification
Table   %l    Recommended Test Equipment .......................                                  ..............    3-2
Table   3-2   Limits for dc Voltage Veriiication .....................                            ..............    3-2
Table   3-3   Limit5 for ac Voltage Verification .....................                            ..............    3-2
Table   34    Limits for Resistance Verification .....................                            ..............    3-3
Table   %5    Limits for dc Cummt Verification   .....................                            ..............    3-3


SECTION 5 - Maintenance
Table 5-1     PoseReplacements..      ..............................                              ..............    5-2
Table 5-2     Recommended Calibration Equipment                        .................          ..............    5-3
Table 5-3     dc Voltage calibration     .............................                            ..............    5-4
Table 5-4     ac Voltage Calibration ..............................                               ..............    54
Table 5-5     Resistance Calibration ..............................                               ..............    5-5
Table 5-6     Recommended Troubleshooting               Equipment                .............    ..............    5-7
TabkS-7       Squdial     Display Test Steps ........................                             ..............    5-8
Table 5-8     Troubleshooting    Modes ............................                               ..............    5-9
Table 59      Power Supply Checks and Battery Pack (Model 1758) Checks                            ..............    5-11
Table 5-10    A/D Converter Checks .............................                                  ..............    5-12
Table 5-11    Display Board Ch&       ..............................                              ..............    5-12


SECTION 6 - Replaceable Parts
Table   6-l   MotherBoard,PartsList        ............................                           ..............    6-11
Table   6-2   DispkiyBoard,PartsList       ............................                           ..............    6-23
Table   6-3   BatteryOptionBoard,Parte.List              ......................                   ..............    6-31
Table   6-4   Model175AVSpareParlsList                 .......................                    ..............    6-39
                                                SECTION 1
                                     General Information

1 .l     INTRODUCTION                                     1.3    WARRANTY INFORMATION
                                                          Warranty information may be found on the inside front
The Keithley Model 175AV is a 4-l/2 digit LCD bench/      cover of this manuaL Should it be necessary to exercise
po~abledigitalmultimeter.TheModel175-AVcanmake            the warranty, contact your Keithley representative or the
the following basic measurements:                         factory to determinetheproper     course of action. Keithley
                                                          Jnshuments maintains service facilities in the United
                                                          States, United Kingdom, and throughout Europe. Infor-
 1.    DC voltage   measurements from 1OpV to 1M)OV.
                                                          mation concerning the application, operation, or service
 2.    Resistance   measurements from 1OmD to 2OOMQ.
                                                          of your instrument may be directed to the applications
 3.    AC voltage   measurements from 1OuV to 750V.       engineer at any of these locations. Check the inside front
 4.    DC current   measurements from lOm4 to 2A.         cover for addresses.
 5.    AC current   measumments from 101~4 to 2A.


                                                          1.4    MANUAL ADDENDA
In addition to the above mentioned measurement capa-
                                                          Information concerning improvements or changes to the
bilities, the Model 175-AV can make dcand ac dB voltage
measurements.                                             instrument that occur after the printing of this manual
                                                          will be found on an addendum sheet included with the
                                                          manual. Be sure to review these changes before attempt-
                                                          ing to operate or service the instrument.

1.2      FEATURES
                                                          1.5     SAFETY SYMBOLS AND TERMS
Some important       Model 175-AV features include:
                                                          The following safety symbols and terms are used in this
                                                          mamtal or found on the Model 175-AV.
. 4-l /2 digit LCD display
. Fast autoranging
l  Bench or portable
l  Digital calibration                                    Then      symbol on the insttument denotes that the user
. lC0-point data logger                                   should refer to the operating instructions in this manual.
. 0.03% basic dcV accuracy
l  Average responding acV and acA
l  dBm/Relative functions                                 The t on the instrument denotes that a hazardous poten-
. Min/Max reading hold                                    tial may be present on the terminal(s). Standard safety
 . Safety input jacks                                     practices should be observed when such dangerous lev-
 l 1OOkHz specified ac bandwidth                          els are encountered.


                                                          The WARNUUG used in this manual explains dangers
Options in&de:                                            that could result in personal injury or death.


 . Model 1758 Rechargeable Battery Pack                   The CAUTION     used in this manual       explains   hazards
 . Model 1753AV IEEE488 Interface                         that could damage the instrument.


                                                                                                                    l-l
SECTION 1
Gemrul Information




1.6        SPECIFICATIONS                                         a Section 4 contains a description of operating theory.
                                                                    Analog, digital, and power supply operation is in-
Detailed Model 175-AVspeciBcations    may be found pre-             cluded.
ceding the Table of Contents of this manual.                      l Section 5 contains information for servicing the instru-
                                                                    ment. This section includes information on line fuse
                                                                    replacement, line voltage selection, calibration and
                                                                    troubleshooting.
1.7        INSPECTION                                             l Section 6 contains replaceable parts information.

The Model 175-AV Autoranging DMM was carefully in-
spected, both electrically and mechanically, before ship-                                   NOTE
ment. After unpacking all items from the shipping car-                  The Model 1753AV IEEE-Q88 interface comes
ton, check for any obvious signs of physical damage that                supplied with its own instruction manual.
might have occurred during transit. Report any damage
totheshippingagent.Retainandusetheoriginalpacking
materials in case reshipment is necessary. The following          1.9    GElTlNG STARTED
items are shipped with every Model 175-AV order:
                                                                  Perform the foBowing steps in sequence to acquaint
                                                                  yourself quickly and safely with the basic operation of
Model 175-AV Autoranging          Multimeter
                                                                  the Model 175AV.
Model 175-AV Instruction       Manuals (2)

Model 1751 Safety Test Leads                                      1. Connect the female end of the power cord to the ac
                                                                     receptacle on the rear panel of the instrument. Con-
Additional     accessories as ordered.                               nect the other end of the cord to a grounded ac outlet.
                                                                     J.ftheoptionalbatterypackisinstalledthechargecir-
                                                                     cuitry will be activated. Refer to paragraph 23.1 for
If an additional instruction manual is required, order the           more complete information.
manual package (Keithley Part Number 175AV-901-00).               2. Turn on the Model 175-AV by pressing in the ON/
The manual package includes an instruction manual and                OFF pushbutton. All of the zeros will be displayed
any applicable addenda.                                              briefly.
                                                                  3. Connect the supplied test leads to the INPUT HI and
                                                                     LO jacks, and short them together.
                                                                  4. Select ac volts and autoranging by pressing in the
1.6        USING THE MODEL 175AV MANUAL                              AC/DC, V, and AUTO pushbuttons. The AC, mV,
                                                                     and ADTO annunciators will be displayed. Pressing
This manual contains information necessary for operat-               any of the other range pushbuttons            will put the
ing and servicing    the Model 175-AV Autoranging                    Model175AVinmanualrangingasindicatedbythe
Multimeter   and the Model 1758 Rechargeable Battery                 absence of the ADTO annun&tor.
Pack. The information is divided into the following sec-          5. Select dc volts by releasing (out) the AC/DC push-
tions:                                                               button W still selected). The AC annunciator will
                                                                     turn off.
                                                                  6. Select autoranging ohms by pressing in the Q push-
                                                                     button (dc still selected) and AUTOuushbutton.         The
      Section 1 contains general information        about the        0 annunciator will turn on. Press &e AC/DC push-
      Model 175-AV and Model 1758, including that neces-             buttonm(acselected)andnotethe"lW'messagein-
      sary to inspsct the instrument and get it operating as         dicatig that this is an invalid mode.
      quickly as possible.                                        7. Select ac or dc current by setting the AC/DC push-
      Section 2 contains detailed operating information on           button accordingly and pressing in the A pushbut-
      using the frant panel controls, making connections,            ton. The annunciator that reflects the selected range
      and basic measuring techniques for each of the avail-          will turn on. Note that current will not autorange.
      able measuring functions.                                   8. Select dB by placing the Model 175-AV in ac or dc
      Section 3 contains performance verification        proce-      volts and pressing the dB pushbutton. The dB an-
      dures for the instrument. This information        will be      nunciator will turn on. Press the dB button again to
      helpful if you wish to verify that the instrument is op-       take the Model 175-AV out of the dB measurement
      erating in compliance with its stated spscifications.          mode.


l-2
                                                                                                          SECTION 1
                                                                                                    Generul Information



 9. REL (relative) can be used with any measurement               Ratio Accuracy: i2.5% from 1kV to 40kV DC, zt3.5%
    function: volts, ohms, amps or dB. For example,               if 2OOmV or 2V ranges of Model 175-AV are used;
    place the Model 175-AV in ohms and autorange. The             -3dB at 3OOHz ac.
    display will read approximately CO.l4G, whichis the           Operating Temperature: 0' to 5O'C
    test lead resistance. Press the RBL pushbutton. The
    REL annunciator will turn on and the display will
    now read OO.OOD.    The relative level of 0.14D will be   Model 1651 50-Ampere Current Shunt - The external
    subtracted from all subsequent ohm measurements.          O.CKllG fl%, 4-terminal shunt permits current measure-
    Press the RBL pushbutton a second time to cancel the      ments from O-50A dc or ac.
    REL level.
10. To activate the loo-point DATA LOGGER with
    MJN/MAX,       press and hold in the STO/CLR push-        Model 1681 Clip-On Test Lead Set-Contains    two leads,
    button. When the reading rate R=O is displayed, let       1.2m (48 inches) long terminated with banana plugs and
     go of the button. The STO' annunciator & turn on.        spring action clip on probes.
    Press the RCL pushbutton and the last data point
    will be displayed briefly followed by the reading
     (data). Other data points can be displayed by hold-      Model1682ARFProbe-Permitsvoltagemeasurements
    ing in the RCL button. Turn off the DATA LOGGER           from lC&Hz to 25OMHz.
    by pressing the STOKLR pushbutton again.                      AC to dc transfer accuracy: fldB from 1OOkHz to
11. When you are comfortable with the controls of the             25OMHz at IV, peak responding, calibrated in rms of
     Model 175-AV, go on and make the desired meas-               a sine wave.
     urements using Section 2, Bench Operation as a               Maximum Allowable Input: 42V ac peak, 200V (dc +
     guide.                                                       ac peak)


1.lO ACCESSORIES                                              Model1684HardShellCatryingCase-Hard          vinylcase,
                                                              lOOmmx300mmx350mm(4x13x14inches)hasafitted
                                                              foam insert with room for the Model 175-AV, instruction
The following accessories are available to enhance Model      manual, and small accessories.
175-AV capabilities:

Model 1010 Single Rack Mounting Kit -Use to mount             Model 1685 Clamp-On AC Probe -Measures          ac current
one Model 175-AV in a standard 5-l/4 x 19" rack.              by clamping onto a single conductor. Interruption    of the
                                                              circuit under test is unnecessary. The Model 1685 detects
                                                              current by sensing the changing magnetic field produced
Model1017DualRackMountingKit-Usetomounttwo                    by the current flow.
Model 175AV's in a standard 5-1/4x 19" rack.                        Range: 2,20 and 200A rms
                                                                    Accuracy: M% of range at 6OHz; z&6% of range at
                                                                    5oHz
                                                                    Temperature Coefficient: M.O5%/"C on 20A and
Model 1301 Temperature Probe - A rugged low cost                    2OOA range; ffl.3%N     on 2A range
temperature probe designed to allow pm&ion tempera-                 Maximum Allowable Current: 300A rms
ture measurements from -55



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