Text preview for : 175_AV_901_01C.pdf part of Keithley 175 AV 901 01C Keithley 175 175_AV_901_01C.pdf
Back to : 175_AV_901_01C.pdf | Home
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 ( e":%T Bm). Resolution: O.OldB above 5% of range.
AC VOLTS ACCURACY Year)*
(1
(average respondinp, W-WC nmdg + counts)
Ml-l?+ IOkHZ-
RANGE zz lOkH2 mkkiz `ii%- iI%%
zv-7mv 05+m 1+40 5+200
mni V ::2 05+m 1.5+40 7*+nn -
`Above II ti munts.
MAxlMl ,M ALLOWABLE INPUT: 75OVm,s, IWOV peak (40 seconds per minute on 2@h"V m"Se; 3OOV"XU ~ontbmous).
.__
107Vwz maximum.
3dB BANDWIDTH: 3OOkI+ t typical.
INPUT IhfPEDANCE: and 1OOOV
IOMI: I ~ralleled by c75pF on 2OV, ZOOV,
_ . . annes. llh4Q on 2OCmVand 2V ""Se.
s&~~hlMiphd.
seconds to within 15 counts of final radii on ran e.
dB MODE trek 6&X-l): AC&& ktdBm)
mHz- wkxiz
RANGE INPUT 1okHz ZOkIiZ 1wkHz
2v-75w 2wmvto75ov 0.2 0.26 0.56 1.2
(-12 to +59.SdBml
200 mv mmvto2wmv 0.2 0.3 1 -
(32 to -12 dBm)
2mVto2OmV 2 3 -
(-52 to -32 dBm)
1 mVto2mV 2. - -
C-58 to -52 dBm)
Resolutian: O.OldB above 5% of range. *Up to 1kHz.
OHMS ACCURACY MAX VOLTAGE
(1 Yea?) ACROSS
lo%wc
RANGE RESOLUnON ti%rdS + comts) tiiEE2
2coD 10 ND 0.05 + 2.
1MmG O.ffi+l
20' iti
200 h-2 1: :: fit2:
2 Ml-2 **
20 MG l * `F&i !a
2w MD ** 1w U-I 20 +1
~~~~~~~~L;~to~ti~liy.
OPEN-CIRCUIT VOLTAGE: +5V.
DIODE TBST: Display reads junctio" voltaSe up to 2V. Test current: 0.7mA
SE'ITLING `I1ME: 2 seconds to withi" 1 count of final reading on range.
DC AMPS MAXlMUM
RANGE RESOLUTION E-T,2if
10 nA
?I2 1M "A i:E
2ii2 1: $ i:E
OVERLOA~PR%TECTlON: 2A'Ese?&OVL externally &&e.
SFITLING TIME: 1 second to within 1 count of final reading.
AC AMPS
(average responding)
n~%rl~cots)
RANGE BURDEN ZOHZ-MHZ 1okHz-3okHz
2w%-2z %Y : 1: i%z 2+50
-
2ummA 05 v 1 +20 o.s+m -
*Above 18W counka.
SElTLlNG TIME: 2 seconds to within 15 c.,"nts of final reading.
IEEE-488 BUS IMPLBMENTATION (Model 1753 0 tion)
MULTILINH COMMAND s: DCL SDC GET GTL L&T, UNL, WE, SPD.
UNILINE COMMANDS: IFC, R!& E61, SRh. Ati.
IWI?XFACE FUNCTIONS: SHl, AHl. T5, TEO, LA, LEO, SRl, RLZ, Pm, DCl, Ml, CO, EL
PROGRAMMABLE Pm s: Range, REL, dB, EOL Trigger, Calibration, SRQ Status, Output Format, Tm,,i,,ator
GENERAL
DISPLAY: 41/Z digit LCD, 0.5 in. height; laity, function, range, and status indication.
RANGING; Auto or manual on IX volts, A c?volts, ohms; manual on AC amps. DC amps.
AUTORANGING TIME: 3LlOmwc. per range.
WARMUP. 1 how to rated accuracy.
RELATlVEz Pushbutton allows zeroing of on range readings. Allows readings to be made with respect to baseline value. Front
and anmmciutor lndlcates REL mode.
DAfA LOGGER and MIN/hlrv(: 100 reading storage capacity; records data at one of six selectable rates from 3 readings/second
to 1 readin /hour. Also deteck and stems maxim UN and xrmimum readings c,,nti,,uawly in data logger mode.
CONVERBIOn8IWD3 3 readings I second.
OVERRANGE INDICATION "g" displa ed.
MAXlMUM COMMON MOdE VOLTAGd 5COV Deat
COMMON MODE RBJIVXTON RATE 0 (1M unb&ncd: >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