Tektronix 2182 Service Manual

Model 2182 Nanovoltmeter

Service Manual

A GREATER MEASURE OF CONFIDENCE

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a
period of 3 years from date of shipment.

Keithley Instruments, 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, or 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 or part. This warranty also does not apply to fuses, software, non-recharge­able batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instruc­tions.

THIS WARRANTY IS IN LIEU OF ALL O THER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING
ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE
REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR
ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT
OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS
BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAM­AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION,
LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

Keithley Instruments, Inc.

BELGIUM: Keithley Instruments B.V. Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02/363 00 40 • Fax: [phone]
CHINA: Keithley Instruments China Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-62022886 • Fax: [phone]
FRANCE: Keithley Instruments Sarl 3, allée des Garays • 91127 Palaiseau Cedex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Keithley Instruments GmbH Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Keithley Instruments Ltd Unit 2 Commerce Park, Brunel Road • Theale • Reading • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: Keithley Instruments GmbH Flat 2B, WILOCRISSA • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
ITALY: Keithley Instruments s.r.l. Viale S. Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: [phone]
NETHERLANDS: Keithley Instruments B.V. Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWITZERLAND: Keithley Instruments SA Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: [phone]
TAIWAN: Keithley Instruments Taiwan 1 Fl. 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3572-9077 • Fax: [phone]

• 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: [phone] • http://www .k eithley.com

4/01

Model 2182 Nanovoltmeter

Service Manual

©1998, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Third Printing, September 2001

Document Number: 2182-902-01 Rev. C

Manual Print History

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

Revision A (Document Number 2182-902-01)......................................................... February 1998

Revision B (Document Number 2182-902-01)................................................................ June 1998

Revision C (Document Number 2182-902-01)...................................................... September 2001

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand names are trademarks or registered trademarks of their respective holders.

Safety Precautions

The following safety precautions should be observed before using this product and any associated in­strumentation. Although some instruments and accessories would normally be used with non-hazardous
voltages, there are situations where hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar
with the safety precautions required to avoid possible injury. Read the operating information carefully
before using the product.

The types of product users are:

Responsible body

ensuring that the equipment is operated within its specifications and operating limits, and for ensuring
that operators are adequately trained.

Operators

and proper use of the instrument. They must be protected from electric shock and contact with hazardous
live circuits.

Maintenance personnel

setting the line voltage or replacing consumable materials. Maintenance procedures are described in the
manual. The procedures explicitly state if the operator may perform them. Otherwise, they should be
performed only by service personnel.

Service personnel

ucts. Only properly trained service personnel may perform installation and service procedures.
Keithley products are designed for use with electrical signals that are rated Installation Category I and

Installation Category II, as described in the International Electrotechnical Commission (IEC) Standard
IEC 60664. Most measurement, control, and data I/O signals are Installation Category I and must not
be directly connected to mains voltage or to voltage sources with high transient over-voltages. Installa­tion Category II connections require protection for high transient over-v oltages often associated with lo­cal AC mains connections. The user should assume all measurement, control, and data I/O connections
are for connection to Category I sources unless otherwise marked or described in the Manual.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable con­nector jacks or test fixtures. The American National Standards Institute (ANSI) states that a shock haz­ard exists when voltage lev els greater than 30V RMS, 42.4V peak, or 60VDC are present.

practice is to expect that hazardous voltage is present in any unknown circuit before measuring.

Users of this product must be protected from electric shock at all times. The responsible body must en­sure that users are prevented access and/or insulated from every connection point. In some cases, con­nections must be exposed to potential human contact. Product users in these circumstances must be
trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or
above 1000 volts,

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with
impedance limited sources. NEVER connect switching cards directly to AC mains. When connecting
sources to switching cards, install protective devices to limit fault current and voltage to the card.

Before operating an instrument, make sure the line cord is connected to a properly grounded power re­ceptacle. Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks be­fore each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a
separate main input power disconnect device must be provided, in close proximity to the equipment and
within easy reach of the operator.

is the individual or group responsible for the use and maintenance of equipment, for

use the product for its intended function. They must be trained in electrical safety procedures

are trained to work on live circuits, and perform safe installations and repairs of prod-

no conductive part of the circuit may be exposed.

perform routine procedures on the product to keep it operating, for example,

A good safety

For maximum safety , do not touch the product, test cables, or an y other instruments while po wer is applied to
the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before:
connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal
changes, such as installing or removing jumpers.

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. Alw ays make measurements with dry hands while standing on a dry, insulated surface ca­pable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with its specifications and operating instructions
or the safety of the equipment may be impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications
and operating information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with same type and rating for continued protection against fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth

ground connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation

requires the use of a lid interlock.
If a screw is present, connect it to safety earth ground using the wire recommended in the user documentation.

!

The symbol on an instrument indicates that the user should refer to the operating instructions located in
the manual.

The symbol on an instrument shows that it can source or measure 1000 volts or more, including the com­bined effect of normal and common mode voltages. Use standard safety precautions to av oid personal contact
with these voltages.

The

WARNING

read the associated information very carefully before performing the indicated procedure.

CAUTION

The
invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, replacement components in mains circuits, including the

power transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses,
with applicable national safety approvals, may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as long as they are equivalent to the original
component. (Note that selected parts should be purchased only through Keithley Instruments to maintain ac­curacy and functionality of the product.) If you are unsure about the applicability of a replacement component,
call a Keithley Instruments office for information.

To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior of the instrument
only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Prod­ucts that consist of a circuit board with no case or chassis (e.g., data acquisition board for installation into a
computer) should never require cleaning if handled according to instructions. If the board becomes contami­nated and operation is affected, the board should be returned to the factory for proper cleaning/servicing.

heading in a manual explains dangers that might result in personal injury or death. Always

heading in a manual explains hazards that could damage the instrument. Such damage may

Rev. 2/01

Table of Contents

1 Performance Verification

Introduction ................................................................................ 1-2

Verification test requirements ..................................................... 1-2

Environmental conditions ................................................... 1-2

Warm-up period .................................................................. 1-3

Line power .......................................................................... 1-3

Recommended test equipment ............................................ 1-3

Verification reading limits ................................................... 1-4

Restoring factory defaults ................................................... 1-4

Auto-calibration (ACAL) .................................................... 1-4

Performing the verification test procedures ............................... 1-5

Test summary ...................................................................... 1-5

Test considerations .............................................................. 1-5

Verification procedures .............................................................. 1-6

Voltage measurement accuracy ........................................... 1-6

Temperature measurement accuracy ................................... 1-8

Analog output accuracy .................................................... 1-10

2 Calibration

Introduction ................................................................................ 2-2

Environmental conditions .......................................................... 2-2

Temperature and relative humidity ..................................... 2-2

Calibration considerations .......................................................... 2-3

Calibration cycle ................................................................. 2-3

Calibration menu ................................................................. 2-3

Calibration errors ................................................................ 2-5

Aborting calibration ............................................................ 2-6

Normal calibration ..................................................................... 2-6

Recommended calibration equipment ................................. 2-6

Front panel calibration ........................................................ 2-6

Remote calibration ............................................................ 2-10

Factory calibration ................................................................... 2-12

Recommended test equipment .......................................... 2-12

Remote factory calibration ................................................ 2-13

3 Routine Maintenance

Introduction ................................................................................ 3-2

Line fuse replacement ................................................................ 3-2

Line voltage selection ................................................................ 3-3

4 Troubleshooting

Introduction ................................................................................ 4-2

Repair considerations ................................................................. 4-2

Power-on self-test ....................................................................... 4-3

Front panel tests .................................................................. 4-3

KEY test .............................................................................. 4-3

DISP test .............................................................................. 4-3

Principles of operation ................................................................ 4-4

Power supply ....................................................................... 4-4

Display board ...................................................................... 4-5

Digital circuitry ................................................................... 4-6

Analog circuitry ................................................................... 4-7

Troubleshooting ........................................................................ 4-10

Display board checks ........................................................ 4-10

Power supply checks ......................................................... 4-11

Digital circuit checks ......................................................... 4-12

Analog circuit checks ........................................................ 4-13

Analog signal switching states .......................................... 4-14

No comm link error ........................................................... 4-16

5 Disassembly

Introduction ................................................................................ 5-2

Handling and cleaning ................................................................ 5-2

Handling PC boards ............................................................ 5-2

Solder repairs ....................................................................... 5-2

Static sensitive devices ........................................................ 5-2

Assembly drawings ..................................................................... 5-3

Disassembly ................................................................................ 5-4

Case cover removal ............................................................. 5-4

Motherboard removal .......................................................... 5-4

Front panel disassembly ...................................................... 5-5

Main CPU firmware replacement ............................................... 5-6

Changing trigger link lines ......................................................... 5-7

Removing power components .................................................... 5-8

Power transformer removal ................................................. 5-8

Power module removal ........................................................ 5-8

Instrument reassembly ................................................................ 5-9

Power module connections .................................................. 5-9

Board installation ................................................................ 5-9

6 Replaceable Parts

Introduction ................................................................................ 6-2

Parts lists .................................................................................... 6-2

Ordering information ................................................................. 6-2

Factory service ........................................................................... 6-2

Component layouts .................................................................... 6-2

A Specifications
B Calibration Reference

Introduction ............................................................................... B-2

Command summary .................................................................. B-3

Default calibration constants and tolerances ............................. B-4

Miscellaneous commands ......................................................... B-6

:CODE ................................................................................ B-6

:COUNT? ........................................................................... B-6

:LOCK ................................................................................ B-7

:SAVE ................................................................................ B-7

:DATE ................................................................................ B-8

:NDUE ............................................................................... B-8

DATA? ................................................................................ B-9

Calibration step commands ....................................................... B-9

:DC ..................................................................................... B-9

Precalibration commands ........................................................ B-10

:PCAL .............................................................................. B-10

Detecting calibration errors ..................................................... B-11

Reading the error queue ................................................... B-11

Error summary ................................................................. B-11

Status byte EAV (Error Available) bit .............................. B-12

Generating an SRQ on error ............................................ B-12

Detecting calibration step completion ..................................... B-12

Using the *OPC? query ................................................... B-12

Using the *OPC command ............................................... B-13

Generating an SRQ on calibration complete ................... B-13

C Calibration Program

Introduction ............................................................................... C-2

Computer hardware requirements ............................................. C-2

Software requirements .............................................................. C-2

Calibration equipment ............................................................... C-2

General program instructions .................................................... C-3

Index

List of Illustrations

1 Performance Verification

Figure 1-1 Connections for 100mV-100V range accuracy ...................... 1-6

Figure 1-2 Connections for 10mV range accuracy .................................. 1-7

Figure 1-3 Connections for temperature accuracy verification ............... 1-9

Figure 1-4 Connections for analog output accuracy .............................. 1-11

2 Calibration

Figure 2-1 Low-thermal short connections .............................................. 2-7

Figure 2-2 Connections for DC volts calibration .................................... 2-8

Figure 2-3 Connections for factory DC volts calibration ...................... 2-14

Figure 2-4 Low thermal short connections for factory calibration ........ 2-15

Figure 2-5 Connections for analog output calibration ........................... 2-16

3 Routine Maintenance

Figure 3-1 Line fuse replacement ............................................................ 3-2

4 Troubleshooting

Figure 4-1 Power supply block diagram .................................................. 4-4

Figure 4-2 Digital circuitry block diagram .............................................. 4-5

Figure 4-3 Simplified schematic of analog circuitry ............................... 4-8

List of Tables

1 Performance Verification

Table 1-1 Recommended verification equipment .................................. 1-3

Table 1-2 Input cable color codes .......................................................... 1-6

Table 1-3 DC voltage measurement accuracy limits .............................. 1-8

Table 1-4 Temperature measurement accuracy limits .......................... 1-10

Table 1-5 Analog output accuracy limits ............................................. 1-11

2 Calibration

Table 2-1 Calibrating menu ................................................................... 2-3

Table 2-2 Recommended normal calibration equipment ....................... 2-6

Table 2-3 Input cable color codes .......................................................... 2-8

Table 2-4 DC volts front panel calibration summary ............................. 2-9

Table 2-5 DC voltage remote calibration programming steps ............. 2-11

Table 2-6 Recommended factory calibration equipment ..................... 2-12

Table 2-7 Remote precalibration steps ................................................. 2-14

Table 2-8 DC voltage remote calibration programming steps ............. 2-15

3 Routine Maintenance

Table 3-1 Power line fuse ratings ........................................................... 3-3

4 Troubleshooting

Table 4-1 Circuit gain factors ............................................................... 4-10

Table 4-2 Display board checks ........................................................... 4-10

Table 4-3 Power supply checks ............................................................ 4-11

Table 4-4 Digital circuit checks ........................................................... 4-12

Table 4-5 Analog circuit checks ........................................................... 4-13

Table 4-6 Signal multiplexing gain switching ..................................... 4-14

Table 4-7 Input protection and low-noise preamplifier analog

switching states .............................................................. 4-15

5 Disassembly

Table 5-1 Trigger link connections ........................................................ 5-7

Table 5-2 Power module connections .................................................... 5-9

6 Replaceable Parts

Table 6-1 Motherboard parts list ............................................................ 6-3

Table 6-2 Display board parts list .......................................................... 6-9

Table 6-3 Connector board parts list .................................................... 6-10

Table 6-4 Mechanical parts list ............................................................ 6-10

B Calibration Reference

Table B-1 Remote calibration command summary ................................ B-3

Table B-2 Default calibration constants and tolerances ......................... B-5

Table B-3 Calibration steps .................................................................... B-9

Table B-4 Precal steps .......................................................................... B-10

Table B-5 Calibration errors ................................................................ B-11

1

Performance

Verification

1-2 Performance Verification

Introduction

Use the procedures in this section to verify that Model 2182 accuracy is within the limits
stated in the instrument’s one-year accuracy specifications. You can perform these verification
procedures:

• When you first receive the instrument to make sure that it was not damaged during
shipment.

• To verify that the unit meets factory specifications.

• To determine if calibration is required.

• Following calibration to make sure it was performed properly.

WARNING

NOTE

The information in this section is intended only for qualified service person­nel. Do not attempt these procedures unless you are qualified to do so. Some
of these procedures may expose you to hazardous voltages, which could
cause personal injury or death if contacted. Use standard safety precautions
when working with hazardous voltages.

If the instrument is still under warranty, and its performance is outside specified lim­its, contact your Keithle y repr esentative or the factory to determine the corr ect course
of action.

Verification test requirements

Be sure that you perform the verification tests:

• Under the proper environmental conditions.

• After the specified warm-up period.

• Using the correct line voltage.

• Using the proper test equipment.

• Using the specified output signals and reading limits.

Environmental conditions

Conduct your performance verification procedures in a test environment with:

• An ambient temperature of 18-28˚C (65-82˚F).

• A relative humidity of less than 70% unless otherwise noted.

Warm-up period

Allow the Model 2182 to warm up for at least 2-1/2 hours before conducting the v erification
procedures. If the instrument has been subjected to temperature extremes (those outside the
ranges stated above), allow additional time for the instrument’s internal temperature to stabilize.
Typically, allow one extra hour to stabilize a unit that is 10˚C (18˚F) outside the specified tem­perature range.

Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.

Line power

The Model 2182 requires a nominal line voltage of 100, 120, 220, or 240V and a line fre­quency of 50 to 60Hz or 400Hz. Verification tests must be performed with the correct line volt­age. If necessary, change the line voltage setting as covered in

Recommended test equipment

T able 1-1 summarizes recommended verification equipment. You can use alternate equipment
as long as that equipment has specifications at least four times better than corresponding Model
2182 specifications. Keep in mind, however , that test equipment accuracy will add to the uncer­tainty of each measurement.

Performance Verification 1-3

Section 3

.

Table 1-1

Recommended verification equipment

Description Manufacturer/Model Specifications*

DC Calibrator Fluke 5700A 100mV: ±14ppm

1V:

±

7ppm

10V:

±

5ppm

100V:

±

7ppm
Low Thermal Divider Keithley 262 100:1 division: ±5ppm
Thermocouple Calibrator Omega CL523 Type J: -200 to 700˚C

Type K, N : -200 to 1300˚C
Type N: -200 to 400˚C
Type E: -200 to 1000˚C
Type R, S: 0 to 1700˚C
Type B: 400 to 1700˚C

±

Digital Multimeter Keithley 2000 1V:
Low Thermal Cable Keithley 2107
Low Thermal Cable Keithley 1506
BNC-to-dual banana jack cable
*DC calibrator specifications shown include total 90-day 23˚C ±5˚C uncertainty at specified output.

±

Model 262 error includes a short-term transfer error of
specification is 90-day, 23˚C ±5˚C full-range value.

5ppm at 23˚C ±1˚C. Digital multimeter

32ppm

1-4 Performance Verification

Verification reading limits

The verification limits stated in this section have been calculated using only the Model 2182

one-year accuracy specifications, and
ticular measurement falls outside the allowable range, recalculate new limits based both on
Model 2182 specifications and corresponding test equipment specifications.

Example limits calculation

As an example of how verification limits are calculated, assume you are testing the 10V DC

voltage range using a 10V input value. Using the Model 2182 10V range one-year accuracy
specification of ±(25ppm of reading + 2ppm of range), the calculated reading limits are:

they do

not

include test equipment uncertainty

. If a par-

Reading limits = 10V ± [(10V
Reading limits = 10V
Reading limits = 10V ± 270
Reading limits = 9.99973 to 10.00027V

Restoring factory defaults

Before performing the verification procedures, restore the instrument to its factory front panel

default conditions as follows:

1. Press SETUP RESTR. The instrument will display the following prompt:

RESTORE: FACT

2. Using either RANGE key, select FACT, then restore the factory default conditions by

pressing ENTER.

NOTE

Y ou can use either RANGE ke y to toggle between FACT and USER setups. Be sure you
use factory defaults for the verification procedures.

Auto-calibration (ACAL)

Before verifying accuracy, perform an auto-calibration to ensure the instrument meets its

specifications. Do the following:

1. Disconnect the test cable from the input jack.

± (250µ

µ

×

25ppm) + (10V × 2ppm)

V + 20µV)

V

CAUTION

2. Turn on the instrument power, and allow the unit to warm up for at least 2-1/2 hours.

3. Press the ACAL key. The instrument will prompt you as follows:

ACAL: LOW-LVL

Do not perform full auto-calibration with a test voltage connected to the
input jack, or the instrument may be damaged.

Performance Verification 1-5

4. Using either RANGE key, select FULL, then press ENTER. The unit will then remind
you to disconnect the input cable:

REMOVE INPUT

5. Make sure the input cable is disconnected, then press ENTER. The unit will then per­form auto-calibration, a process that will take several minutes to complete. During this
period, the unit will display:

ACAL

NOTE

LOW-L VL ACAL performs a new gain calibration for the 10mV range only based on
10V calibration. FULL A CAL performs both a 100V and 10mV gain calibration based
on the last 10V calibration.

Performing the verification test procedures

Test summary

• DC voltage measurement accuracy

• Temperature measurement accuracy

• Analog output accuracy

If the Model 2182 is not within specifications and not under warranty , see the calibration pro-

cedures in

Section 2

Test considerations

When performing the verification procedures:

• Be sure to restore factory front panel defaults, and perform a full auto-calibration
(ACAL), as outlined above.

• Make sure that the Model 2182 and test equipment are properly w armed up, and that the
test equipment is connected to the appropriate Model 2182 jacks.

• Be sure the test equipment is set up for the proper function and range.

• Allow the test signal to settle before making a measurement.

• Use only copper-to-copper connections to minimize thermal EMFs.

• Make sure that all connections are clean and free of oxidation to avoid thermal EMFs
that could affect measurement accuracy. Clean oxidation from connector terminals with
DeoxIT cleaning solution.

• Keep test connections and all equipment away from drafts to avoid thermal drift.

• Do not connect test equipment to the Model 2182 through a scanner, multiplexer, or
other switching equipment.

• Do not use autoranging because autorange hysteresis may cause the Model 2182 to be
on an incorrect range.

for information on calibrating the unit.

1-6 Performance Verification

WARNING

The maximum voltage between any terminals to chassis ground is 350V
peak. Exceeding this value may cause a breakdown in insulation, creating
a shock hazard.

CAUTION

The maximum voltage between CHANNEL 1 HI and LO is 120V. The max­imum voltage between CHANNEL 2 HI and LO is 12V. Exceeding these
voltage values may result in instrument damage.

Verification procedures

Voltage measurement accuracy

Follow the steps below to verify that Model 2182 voltage measurement accuracy is within
specified limits. The test involves applying precise DC voltages and then verifying that the
Model 2182 voltage readings are within required limits.

100mV – 100V range accuracy

1. W ith the po wer of f, connect the DC calibrator to CHANNEL 1 of the Model 2182 input
jack, as shown in Figure 1-1. Connections for the Model 2107 Lo w Thermal Input Cable
are summarized in Table 1-2.

Table 1-2

Input cable color codes

Input connection Wire color

Channel 1 HI
Channel 1 LO
Channel 2 HI
Channel 2 LO

Figure 1-1

Connections for 100mV-100V range accuracy

2107 Low
Thermal Cable

CHANNEL 1

!

CHANNEL 2

Model 2182

Red (CH1)
Green (CH2)

Black (CH1)
White (CH2)

Red
Black
Green
White

OUTPUT HI

OUTPUT LO

DC Voltage Calibrator

2. Turn on the power, and allow a 2-1/2 hour warm-up period.

3. Restore factory defaults, and do a full auto-calibration, as previously described.

4. Select the Model 2182 DCV1 measurement function, and select the 100mV range.

5. Set the calibrator output to 0.00000mV, and allow the reading to settle.

6. Enable REL, and leave it enabled for the remainder of the tests.

7. Verify reading accuracy for each of the voltages listed in Table 1-3. For each test point:

• Select the correct Model 2182 measurement range.

• Set the DC calibrator output voltage to the indicated value.

• Verify that the Model 2182 voltage reading is within the limits given in the table.

8. Repeat step 7 for negative source voltages with the same magnitudes as those listed in
Table 1-3.

9. Repeat steps 4 through 8 for the 100mV-10V ranges of the CHANNEL 2 input. Be sure
to connect the calibrator to the appropriate input jack terminals by changing input cable
wire connections, and select the DCV2 measurement function.

10mV range accuracy

1. With the power off, connect the DC calibrator and low-thermal divider to the Model
2182 CHANNEL 1 terminals of the input jack, as shown in Figure 1-2.

Figure 1-2

Connections for 10mV range accuracy

Performance Verification 1-7

Model 2182

Wrap Connections
in Foam Insulation

1506 Low

Thermal Cable

2107 Low
Thermal Cable

CHANNEL 1

CHANNEL 2

HI

OUTPUT

!

SENSE

OUTPUT

LO

OUTPUT

HI

LO

LO

SENSE

HI LO

INPUT

Model 262

Low Thermal

Divider

SENSE HI

DC Voltage Calibrator

Copper #18 AWG
insulated wire (Solid
or Stranded)

2. Turn on the power, and allow a 2-1/2 hour warm-up period.

3. Select the Model 2182 DCV1 measurement function, and choose the 10mV range.

4. Select the 100:1 divider ratio.

5. Set the calibrator output to 0.00000V, and allow the reading to settle.

6. Enable REL.

1-8 Performance Verification

7. Set the DC calibrator output voltage to 1.000000V.

8. Verify voltage reading accuracy for the 10mV range listed in Table 1-3.

9. Repeat steps 7 and 8 for a neg ative 10mV source v oltage by setting the calibrator voltage
to –1.00000V.

Table 1-3

DC voltage measurement accuracy limits

Model 2182 range Calibrator voltage setting

10mV*
100mV
1V
10V
100V*

***Channel 1 only.
***Use 100:1 divider ratio and 1.000000V calibrator voltage.

***99.9963 to 100.0037mV for channel 2.

10.00000mV**

100.0000mV

1.000000V

10.00000V

100.0000V

Temperature measurement accuracy

Follow the steps below to verify that Model 2182 temperature measurement accuracy is
within specified limits. This procedure in volv es applying thermocouple v oltages from a temper ­ature calibrator and then verifying that Model 2182 temperature measurements are within
required limits.

NOTE

If the Model 2182 meets its DC volts accuracy specifications, temperature accuracy
is automatically guaranteed, and it is not necessary to verify temperature measure­ment accuracy. However, the following procedure is provided for those who wish to
independently measure temperature measurement accuracy.

Reading limits
(1 Year, 18˚C-28˚C)

9.99460 to 100.00540mV

99.9966 to 100.0034mV***

0.999973 to 1.000027V

9.99973 to 10.00027V

99.9961 to 100.0039V

1. W ith the po wer of f, connect the temperature calibrator to the Model 2182 CHANNEL 1
input jack, as shown in Figure 1-3. Connect the free ends of the thermocouple wire se­curely to the Model 2107 cable lugs, and observe proper polarity (thermocouple + to HI;
thermocouple – to LO). Place the connections in a 0˚C ice bath as shown.

Figure 1-3

Connections for temperature accuracy verification

CHANNEL 1

LO

STEP CH2 CH3 CH4 CH5 CH6 CH7 CH8 CH9 CH10
TALK
LSTN
SRQ
SHIFT
TIMER

HOLD TRIG FAST MED SLOW AUTO ERR

MX+B

SHIFT

DCV1

DELAY

LOCAL

EX TRIG

POWER

CONFIG HALT

STEP SCAN

TYPE

FILT REL

LIMITS

GPIB

DIGITS RATE

OUTPUT

ON/OFFVALUE

RS232

BUFFER

STAT

2182 NANOVOLTMETER

A

OUT

TEMP

1

CAL TEST

EXIT ENTER

MATH
REAR

4W

TCOUPL

SCAN

CH1REM

REL FILT

V1-V

2

%

L

SYNC

ACAL

DCV2

V

1

/

V

2

HOLD

BUFFER

TRIG

STORE

RECALL

SETUP

SAVE RESTR

HI

!

HI

LO

CHANNEL 2

TEMP

2

120V MAX

RANGE

AUTO

12V MAX

RANGE

I

CAT

350V PEAK ANY

TERMINAL TO CHASSIS

Model 2182

Performance Verification 1-9

2107 Cable

Thermocouple
Wires

Connect Wires
in Ice Bath

Calibrator

2. Turn on the power, and allow a 2-1/2 hour warm-up period.

3. Press SHIFT then TCOUPL, then use the RANGE and left and right arro w k eys to select
the following:

• UNITS: C

• JUNC: SIM, set to 0˚C

• TYPE: J

• SENS: TCOUPLE

4. Select the Model 2182 TEMP 1 function.

Thermocouple

1-10 Performance Verification

5. Verify temperature measurement accuracy for each of the temperature settings listed in
Table 1-4. For each measurement:

• Set the Model 2182 for the appropriate thermocouple type.

• Set the temperature calibrator to the correct thermocouple type and temperature

setting.

• Verify that the Model 2182 temperature reading is within the limits given in the

table.

Table 1-4

Temperature measurement accuracy limits

Thermocouple type

J, K, N, T
J, K, N, T
J, K, N, T
J, K, N
K, N

E
E
E

R, S
R, S, B
R, S, B

Analog output accuracy

Use the following procedure to verify accuracy of the analog output.

NOTE

Be sure that DC voltage measurement accuracy is within required limits before
attempting this procedure.

Temperature calibrator setting
(˚C)

-200
0
400
700
1300

-200
0
1000

0
400
1700

Model 2182 temperature
reading limits
(1 Year, 18˚C-28˚C)

-200.2 to –199.8˚C

-0.2 to 0.2˚C

399.8 to 400.2˚C

699.8 to 700.2˚C

1299.8 to 1300.2˚C

-200.2 to -199.8˚C

-0.2 to 0.2˚C

999.8 to 1000.2˚C

-0.2 to 0.2˚C

399.8 to 400.2˚C

1699.8 to 1700.2˚C

1. W ith the po wer of f, connect the Model 2182 CHANNEL 1 input jack to the DC voltage
calibrator, and connect the rear panel ANALOG output jack to the digital multimeter, as
shown in Figure 1-4.

Figure 1-4

Connections for analog output accuracy

SCAN

STEP CH2 CH3 CH4 CH5 CH6 CH7

CH1REM

TALK
LSTN
SRQ
SHIFT

HOLD

TIME

TRIG FAST MED SLOWAUTO

R

Model 2000 DMM

MATH

CH9

CH8

CH

REAR

10

4W

STAT

BUFFER

ERR

REL FILT

2001 MULTIMETER

Connect to
ANALOG OUTPUT
on Rear Panel

CHANNEL 1

!

CHANNEL 2

BNC to Dual
Banana Adapter

2107 Low
Thermal Cable

OUTPUT HI

OUTPUT LO

Performance Verification 1-11

DC Voltage Calibrator

2. Select the Model 2182 DCV1 measurement function, and choose the 10V range.

3. Press SHIFT then AOUT, then use the RANGE and left and right arrow keys to set the
following:

• STATE: ON

• M: +1.0000000

• B: +00.000000

4. Set the calibrator voltage to 0.00000V, then enable the Model 2182 REL mode. Also en­able REL on the digital multimeter.

5. Verify analog output accuracy for each of the voltages listed in Table 1-5. For each test
point:

• Set the DC calibrator voltage to the indicated value.

• Verify that the digital multimeter voltage reading is within the limits given in the

table.

Table 1-5

Analog output accuracy limits

Calibrator voltage Nominal analog output value Analog output voltage limits

2.500000V

5.000000V

7.500000V

10.00000V

0.25V

0.5V

0.75V
1V

0.24875 to 0.25125V

0.4985 to 0.5015V

0.74825 to 0.75175V

0.998 to 1.002V

1-12 Performance Verification

2

Calibration

2-2 Calibration

Introduction

Use the procedures in this section to calibrate the Model 2182. These procedures require ac­curate test equipment to supply precise DC voltages. Calibration can be performed either from
the front panel, or by sending SCPI calibration commands over the IEEE-488 b us or RS-232 port
with the aid of a computer.

There are two general types of calibration covered in this section:

• Normal calibration: Usually the only type of calibration required in the field.

• Factory calibration: Required only if the Model 2182 has been repaired, or if a +516,
“Linearity Precal Lost” error occurs.

WARNING

The information in this section is intended only for qualified service person­nel. Do not attempt these procedures unless you are qualified to do so. Some
of these procedures may expose you to hazardous voltages.

Environmental conditions

Temperature and relative humidity

Conduct the calibration procedures at an ambient temperature of 18-28˚C (65-82˚F) with rel-

ative humidity of less than 70% unless otherwise noted.

Warm-up Period

Allow the Model 2182 to warm up for at least 2-1/2 hours before performing calibration.

If the instrument has been subjected to temperature extremes (those outside the ranges stated
above), allow additional time for the instrument’s internal temperature to stabilize. Typically, al­low one extra hour to stabilize a unit that is 10˚C (18˚F) outside the specifi ed temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.

Line Power

The Model 2182 requires a nominal line voltage of 100, 120, 220, or 240V and a line frequen­cy of 50 to 60Hz or 400Hz. Calibration must be performed with the correct line voltage. If nec­essary, change the line voltage setting as covered in

Section 3

.

Calibration considerations

When performing the calibration procedures:

• Make sure that the test equipment is properly w armed up and connected to the appropri­ate Model 2182 jack.

• Always allow the source signal to settle before calibrating each point.

• Use only copper-to-copper connections to minimize thermal EMFs.

• Make sure that all connections are clean and free of oxidation to avoid thermal EMFs
that could affect calibration accuracy. Clean oxidation from connector terminals with
DeoxIT cleaning solution.

• Keep test connections and all equipment away from drafts to avoid thermal drift.

• Do not connect test equipment to the Model 2182 through a scanner or other switching
equipment.

• If an error occurs during calibration, the Model 2182 will generate an appropriate error
message. See

Appendix B

Calibration 2-3

for more information.

WARNING

CAUTION

The maximum voltage between terminals to chassis ground is 350V peak.
Exceeding this value may cause a breakdown in insulation, creating a shock
hazard.

The maximum voltage between CHANNEL 1 HI and LO is 120V. The max­imum voltage between CHANNEL 2 HI and LO is 12V. Exceeding these
voltage values may result in instrument damage.

Calibration cycle

Perform calibration every two years to ensure the unit meets or exceeds its specifications.

Calibration menu

The calibration menu allows you to access the calibration items summarized in Table 2-1. To
access the calibration menu, press SHIFT then CAL. Use the RANGE and left and right arrow
keys to scroll through selections. Use the ENTER ke y to choose menu items, and use the EXIT
key to cancel them.

Table 2-1

Calibrating menu

Calibration menu item Description

CAL: DATES Display calibration and calibration due dates.
CAL: COUNT Display number of times unit was calibrated.
CAL: RUN Run calibration procedure.
CAL: TEMP Display internal calibration temperature.

2-4 Calibration

Calibration dates

Choose the DATES selection in the calibration menu to display the date the Model 2182 was
calibrated and the date calibration is due. The unit will display these dates as in the examples
below:

DATE:12/07/97

NDUE:12/08/98

Calibration count

Choose the COUNT selection in the calibration menu to display the number of times the unit
was calibrated. The instrument will display the calibration count as in this example:

COUNT: 1

Calibration temperature

Select TEMP to display the internal temperature of the unit at the time it was calibrated; for
example:

TEMP: 27.61

Calibration code

Before performing calibration, you must first unlock calibration by entering or sending the
calibration code as discussed below.

Front panel code

1. Access the calibration menu by pressing SHIFT CAL, and note that the instrument dis­plays the following:

CAL: DATES

2. Use the up or do wn RANGE key to scroll through the available calibration menu items
until the unit displays RUN, then press ENTER.

3. The Model 2182 then prompts you to enter a code:
CODE? 000000

(The factory default code is 002182.) Use the left and right arrow keys to move among
the digits; use the up RANGE key to increment numbers, and press the down RANGE
key to specify alphabetic letters. Confirm the code by pressing ENTER.

4. The Model 2182 allows you to define a new calibration code.
NEW CODE? N