Tektronix 2440 Service Manual

Model 2440

Service Manual

2440-902-01 Rev. B / December 2004

www.keithley.com

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WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship
for a period of one (1) year from date of shipment.

Keithley Instruments, Inc. warran
probes, cables, software, rechargeable batteries, diskettes, and documentation.

During the warranty period, Keithley Instruments will, at its option, ei
proves to be defective.

To exercise this warranty, write or call your local Keithley Instruments representative, or contact

thley Instruments headquarters in Cleveland, Ohio. You will be given prompt assistance and

Kei
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.

ts the following items for 90 days from the date of shipment:

ther repair or replace any product that

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley
Instruments’ 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 OTHER W
INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE THE BUYER’S SOLE AND
EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY
FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

ING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE, EVEN IF KEITHLEY

ARIS
INSTRUMENTS, INC. HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH
DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COST
OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY
PERSON, OR DAMAGE TO PROPERTY.

ARRANTIES, EXPRESSED OR IMPLIED,

OF ITS EMPLOYEES SHALL BE LIABLE

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139

440-248-0400 • Fax: [phone] • 1-888-KEITHLEY (1-888-534-8453) • www.keithley.com

3/07

Model 2440 5A SourceMeter

Service Manual

®

©2001, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, December 2004

Document Number: 2440-902-01 Rev. B

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created
for this manual. The Revision Level letter increases alphabetically as the manual undergoes sub
sequent 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 Revision is created, all Addenda associated with the previous Revi
sion 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 A (Document Number 2440-902-01)................................................................ April 2001

Revision B (Document Number 2440-902-01)........................................................Decmeber 2004

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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 and follow all installation, operation, and maintenance
information carefully before using the product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.
The types of product users are:
Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring

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

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper
use of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example,
setting the line voltage or replacing consumable materials. Maintenance procedures are described in the user
documentation. The procedures explicitly state if the operator may perform them. Otherwise, they should be
performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly
trained service personnel may perform installation and service procedures.

Keithley Instruments products are designed for use with electrical signals that are rated Measurement Category I
and Measurement Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC

60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly
connected to mains voltage or to voltage sources with high transient over-voltages. Measurement Category II
connections require protection for high transient over-voltages often associated with local AC mains connections.
Assume all measurement, control, and data I/O connections are for connection to Category I sources unless
otherwise marked or described in the user documentation.

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
levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect that hazardous
voltage is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that
operators are prevented access and/or insulated from every connection point. In some cases, connections must be
exposed to potential human contact. Product operators 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, no conductive
part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance­limited 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 recep tacle.
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.

04/09

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the

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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. Always 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 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 the 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 means caution, risk of danger. The user should refer to the operating instructions

located in the user documenta ti on in all case s where the symbol is marked on the instrument.
The symbol on an instrument means caution, risk of danger. User standard safety precautions to avoid

personal contact with these voltages.
The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

The symbol indicates a connection terminal to the equipment frame.

If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp
must be properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains dangers that might result in personal injury or death.
Always read the associated information very carefully before performing the indicated procedure.

The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such
damage may 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, rep lacement 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.

T o 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.

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

1Ω resistor characterization ................................................ 1-4

Verification limits ...................................................................... 1-5

Example limits calculation .................................................. 1-5

Resistance limits calculation ............................................... 1-5

Restoring factory defaults .......................................................... 1-6

Performing the verification test procedures ............................... 1-6

Test summary ...................................................................... 1-6

Test considerations ............................................................. 1-7

Setting the source range and output value .......................... 1-7

Setting the measurement range ........................................... 1-8

Compliance considerations ........................................................ 1-8

Compliance limits ............................................................... 1-8

Types of compliance ........................................................... 1-8

Maximum compliance values ............................................. 1-9

Determining compliance limit ............................................ 1-9

Taking the SourceMeter out of compliance ...................... 1-10

Output voltage accuracy ........................................................... 1-10

Voltage measurement accuracy ............................................... 1-12

Output current accuracy .................................................... 1-13

Current measurement accuracy ................................................ 1-16

Resistance measurement accuracy ........................................... 1-18

10mA to 1A range accuracy ...................................... 1-13

5A range accuracy ..................................................... 1-14

10mA to 1A range accuracy ...................................... 1-16

5A range accuracy ..................................................... 1-17

2Calibration

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

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

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

Warm-up period .................................................................. 2-2

Line power .......................................................................... 2-2

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

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

Recommended calibration equipment ................................. 2-4

1Ω resistor characterization ................................................ 2-4

Unlocking calibration ................................................................. 2-5

Unlocking calibration from the front panel ......................... 2-5

Unlocking calibration by remote ......................................... 2-6

Changing the password ............................................................... 2-7

Changing the password from the front panel ...................... 2-7

Changing the password by remote ...................................... 2-7

Resetting the calibration password ............................................. 2-8

Viewing calibration dates and calibration count ........................ 2-8

Calibration errors ........................................................................ 2-8

Front panel error reporting .................................................. 2-8

Remote error reporting ........................................................ 2-9

Front panel calibration ................................................................ 2-9

Step 1: Prepare the Model 2440 for calibration ........... 2-9

Step 2: Voltage calibration ......................................... 2-10

Step 3: Current calibration ......................................... 2-13

Step 4: Enter calibration dates and save calibration . 2-17

Step 5: Lock out calibration ...................................... 2-17

Remote calibration .................................................................... 2-18

Remote calibration commands .......................................... 2-18

Recommended calibration parameters .............................. 2-19

Remote calibration procedure ........................................... 2-20

Step 1: Prepare the Model 2440 for calibration ......... 2-20

Step 2: Voltage calibration ......................................... 2-21

Step 3: Current calibration ........................................ 2-23

Step 4: Program calibration dates .............................. 2-25

Step 5: Save calibration constants .............................. 2-25

Step 6: Lock out calibration ....................................... 2-25

Single-range calibration ............................................................ 2-25

3 Routine Maintenance

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

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

4 Troubleshooting

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

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

Power-on self-test ...................................................................... 4-2

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

KEYS test ........................................................................... 4-3

DISPLAY PATTERNS test ................................................ 4-3

CHAR SET test ................................................................... 4-4

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

Overall block diagram ........................................................ 4-4

Analog circuits .................................................................... 4-4

Power supply ....................................................................... 4-7

Output stage ........................................................................ 4-8

A/D converter ..................................................................... 4-9

Active guard ........................................................................ 4-9

Digital circuitry ................................................................. 4-10

Display board circuit theory ............................................. 4-11

Troubleshooting ....................................................................... 4-12

Display board checks ........................................................ 4-12

Power supply checks ......................................................... 4-12

Digital circuitry checks ..................................................... 4-13

Analog circuitry checks .................................................... 4-14

Battery replacement ................................................................. 4-14

Battery replacement precautions ....................................... 4-15

Battery replacement procedure ......................................... 4-15

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

5Disassembly

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

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

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

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

Static sensitive devices ............................................................... 5-3

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

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

Analog board removal ................................................................ 5-5

Digital board removal ................................................................ 5-6

Front panel disassembly ............................................................. 5-6

Removing power components .................................................... 5-7

Power module removal ....................................................... 5-7

Instrument reassembly ............................................................... 5-7

6 Replaceable Parts

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

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

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

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

Component layouts ..................................................................... 6-3

A Specifications

B Command Reference

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

Command summary ................................................................... B-2

Miscellaneous commands .......................................................... B-3

CODE .......................................................................... B-3

COUNT? ..................................................................... B-3

LOCK .......................................................................... B-4

SAVE .......................................................................... B-4

DATE .......................................................................... B-5

NDUE .......................................................................... B-5

SENSE ........................................................................ B-6

SOURCE ..................................................................... B-7

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

Detecting calibration errors ....................................................... B-9

Reading the error queue ..................................................... B-9

Error summary .................................................................... B-9

Status byte EAV (Error Available) bit ............................. B-10

Generating an SRQ on error ............................................. B-10

Detecting calibration step completion ..................................... B-11

Using the *OPC? query .................................................... B-11

Using the *OPC command ............................................... B-11

Generating an SRQ on calibration complete .................... B-12

C Calibration Programs

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

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

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

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

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

Program C-1 Model 2440 calibration program ....... C-4

Requesting calibration constants ............................................... C-7

Program C-2 Requesting calibration constants ....... C-7

List of Illustrations

1 Performance Verification

Figure 1-1 Connections for voltage verification tests ........................... 1-10

Figure 1-2 Connections for 10µA to 1A range current verification tests 1-13

Figure 1-3 Connections for 5A range current verification tests ............ 1-14

Figure 1-4 Connections for resistance accuracy verification ................ 1-18

2Calibration

Figure 2-1 Voltage calibration test connections .................................... 2-10

Figure 2-2 10µA to 1A range current calibration test connections ....... 2-13

Figure 2-3 5A range current calibration test connections ..................... 2-15

3 Routine Maintenance

Figure 3-1 Rear panel .............................................................................. 3-2

4 Troubleshooting

Figure 4-1 Overall block diagram ........................................................... 4-5

Figure 4-2 Analog circuitry block diagram ............................................. 4-6

Figure 4-3 Power supply block diagram ................................................. 4-7

Figure 4-4 Output stage simplified schematic ......................................... 4-8

Figure 4-5 Digital circuitry block diagram ............................................ 4-10

List of Tables

1 Performance Verification

Table 1-1 Recommended verification equipment .................................. 1-4

Table 1-2 Maximum compliance values ................................................ 1-9

Table 1-3 Output voltage accuracy limits ............................................. 1-11

Table 1-4 Voltage measurement accuracy limits ................................. 1-12

Table 1-5 Output current accuracy limits ............................................. 1-15

Table 1-6 Current measurement accuracy limits .................................. 1-17

Table 1-7 Ohms measurement accuracy limits ..................................... 1-19

2Calibration

Table 2-1 Recommended calibration equipment .................................... 2-4

Table 2-2 Calibration unlocked states .................................................... 2-6

Table 2-3 Front panel voltage calibration ............................................. 2-12

Table 2-4 Front panel current calibration ............................................. 2-16

Table 2-5 Remote calibration command summary ............................... 2-18

Table 2-6 Recommended :CALibration:PROTected:SENse

Table 2-7 Recommended :CALibration:PROTected:SOURce

Table 2-8 Voltage calibration initialization commands ....................... 2-22

Table 2-9 Voltage range calibration commands ................................... 2-22

Table 2-10 Current calibration initialization commands ........................ 2-24

Table 2-11 Current range calibration commands ................................... 2-24

parameter ranges .................................................................. 2-19

parameter ranges .................................................................. 2-20

3 Routine Maintenance

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

4 Troubleshooting

Table 4-1 Display board checks ........................................................... 4-12

Table 4-2 Power supply checks ............................................................ 4-12

Table 4-3 Digital circuitry checks ........................................................ 4-13

Table 4-4 Analog circuitry checks ........................................................ 4-14

6 Replaceable Parts

Table 6-1 Analog board parts list ........................................................... 6-3

Table 6-2 Digital board parts list .......................................................... 6-12

Table 6-3 Display board parts list ......................................................... 6-17

Table 6-4 Miscellaneous parts list ........................................................ 6-18

B Command Reference

Table B-1 Remote calibration command summary ............................... B-2

Table B-2 Recommended :CALibration:PROTected:SENSe

parameter ranges ................................................................... B-7

Table B-3 Recommended :CALibration:PROTected:SOURce

parameter ranges ................................................................... B-8

Table B-4 Calibration errors ................................................................ B-10

1

Performance Verification

Performance Verification

1-2 Performance Verification Model 2440 5A SourceMeter® Service Manual

Introduction

Use the procedures in this section to verify that Model 2440 accuracy is within the limits
stated in the instrument’s one-year accuracy specifications. You can perform these verifi
cation 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 The information in this section is intended for qualified service per-

sonnel only. Do not attempt these procedures unless you are qualified
to do so. Some of these procedures may expose you to hazardous volt
ages, which could cause personal injury or death if contacted. Use
standard safety precautions when working with hazardous voltages.

NOTE If the instrument is still under warranty and its performance is outside specified

limits, contact your Keithley representative or the factory to determine the cor
rect course of action.

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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.

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-3

Warm-up period

Allow the Model 2440 to warm up for at least one hour before conducting the verification
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 2440 requires a line voltage of 100 to 240V and a line frequency of 50 to
60Hz. Verification tests must be performed within this range.

Recommended test equipment

Table 1-1 summarizes recommended verification equipment. You can use alternate equip-

ment as long as that equipment has specifications at least as good as those listed in Table

1-1. Keep in mind, however, that test equipment uncertainty will add to the uncertainty of

each measurement. Generally, test equipment uncertainty should be at least four times bet­ter than corresponding Model 2440 specifications. Table 1-1 lists the specifications of the
recommended test equipment, including maximum allowable uncertainty for alternate test
equipment, which is shown in parentheses.

Performance Verification

1-4 Performance Verification Model 2440 5A SourceMeter® Service Manual

Table 1-1

Recommended verification equipment

Description Manufacturer/Model Specifications

Digital Multimeter Hewlett Packard

HP3458A

Resistance Calibrator Fluke 5450A Resistance** 1.9Ω:

DC Voltage* 1V:

10V:
100V:

DC Current* 10μA:

100μA:
1mA:
10mA:
100mA:
1A:

19Ω:
190Ω:

1.9kΩ:
19kΩ:
190kΩ:

1.9MΩ:
19MΩ:

±5.6ppm
±4.3ppm
±6.3ppm

±25ppm
±23ppm
±20ppm
±20ppm
±35ppm
±110ppm

±65ppm (±460ppm)
±23ppm (±280ppm)
±10.5ppm (±230ppm)
±8ppm (±200ppm)
±7.5ppm (±195ppm)
±8.5ppm (±200ppm)
±11.5ppm (±180ppm)
±30ppm (±635ppm)

Precision Resistor*** Isotec RUG-Z-1R00-0.1 1Ω, ±0.1%, 100W

* 90-day, full-range accuracy specifications of ranges required for various measurement points.

** 90-day, ±5°C specifications of nominal resistance values shown. Use actual values for tests. Maximum uncertainty of alternate

test equipment shown in parentheses.

*** Required for verification of 5A current range. Characterize resistor to ±300ppm or better using recommended DMM before ver-

ifying 5A current measurement range.

1Ω resistor characterization

The recommended 1Ω resistor should be characterized to ±300ppm or better before veri­fying the 5A current measurement range. (You need not characterize the resistor if you are
checking only the 5A current source range.) Use the 4-wire ohms function of the DMM
recommended in
value to calculate the current during the 5A current measurement range test procedure.

Table 1-1 to measure the resistance value, and then use that measured

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-5

Verification limits

The verification limits stated in this section have been calculated using only the Model
2440 one-year accuracy specifications, and they do not include test equipment uncer
tainty. If a particular measurement falls outside the allowable range, recalculate new lim­its based on Model 2440 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 output range using a 10V output value. Using the Model 2440 10V range one-year
accuracy specification of ±(0.02% of output + 1.2mV offset), the calculated output limits
are:

Output limits = 10V ± [(10V × 0.02%) + 1.2mV]
Output limits = 10V ± (0.002 + 0.0012)
Output limits = 10V ± 3.2mV
Output limits = 9.9968V to 10.0032V

Resistance limits calculation

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Performance Verification

When verifying the resistance measurement accuracy, it will probably be necessary to
recalculate resistance limits based on the actual calibrator resistance values. You can cal
culate resistance reading limits in the same manner described above, but be sure to use the
actual calibrator resistance values and the Model 2440 normal accuracy specifications for
your calculations.

As an example, assume you are testing the 20kΩ range, and that the actual value of the
nominal 19kΩ calibrator resistor is 19.01kΩ. Using the Model 2440 20kΩ range one-year
normal accuracy specifications of ±(0.06% of reading + 3Ω), the recalculated reading
limits are:

Reading limits = 19.01kΩ ± [(19.01kΩ × 0.06%) + 3Ω]
Reading limits = 19.01kΩ ±14.4Ω
Reading limits = 18.9956kΩ to 19.0244kΩ

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1-6 Performance Verification Model 2440 5A SourceMeter® Service Manual

Restoring factory defaults

Before performing the verification procedures, restore the instrument to its factory front
panel (bench) defaults as follows:

1. Press the MENU key. The instrument will display the following prompt:

MAIN MENU

SAVESETUP COMMUNICATION CAL ©

2. Select SAVESETUP, and then press ENTER. The unit then displays:

SAVESETUP MENU

GLOBAL SOURCE-MEMORY

3. Select GLOBAL, and then press ENTER. The unit then displays:

GLOBAL SETUP MENU

SAVE RESTORE POWERON RESET

4. Select RESET, and then press ENTER. The unit displays:

RESET ORIGINAL DFLTS

BENCH GPIB

5. Select BENCH, and then press ENTER. The unit then displays:

RESETTING INSTRUMENT

ENTER to confirm; EXIT to abort

6. Press ENTER to restore bench defaults, and note the unit displays the following:

RESET COMPLETE

BENCH defaults are now restored ©
ß Press ENTER to continue

7. Press ENTER then EXIT as necessary to return to normal display.

Performing the verification test procedures

Test summary

• DC voltage output accuracy

• DC voltage measurement accuracy

• DC current output accuracy

• DC current measurement accuracy

• Resistance measurement accuracy

If the Model 2440 is not within specifications and not under warranty, see the calibration
procedures in

Section 2 for information on calibrating the unit.

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-7

Test considerations

When performing the verification procedures:

• Be sure to restore factory front panel defaults as previously outlined.

• Make sure that the test equipment is properly warmed up and connected to the
Model 2440 INPUT/OUTPUT jacks. Also be sure that the front panel jacks are
selected with the TERMINALS key.

• Make sure the Model 2440 is set to the correct source range (see below).

• Be sure that the Model 2440 output is turned on before making measurements.

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

• Allow the Model 2440 output signal to settle before making a measurement.

• Do not connect test equipment to the Model 2440 through a scanner, multiplexer,
or other switching equipment.

WARNING The maximum common-mode voltage (voltage between LO and chas-

CAUTION The maximum voltage between INPUT/OUTPUT HI and LO or 4-

Performance Verification

sis ground) is 40V peak. Exceeding this value may cause a breakdown
in insulation, creating a shock hazard.

WIRE SENSE HI and LO is 42V peak. The maximum voltage between
INPUT/OUTPUT HI and 4-WIRE SENSE HI or between INPUT/
OUTPUT LO and 4-WIRE SENSE LO is 5V. Exceeding these voltage
values may result in instrument damage.

Setting the source range and output value

Before testing each verification point, you must properly set the source range and output
value as outlined below.

1. Press either the SOURCE V or SOURCE I key to select the appropriate source
function.

2. Press the EDIT key as required to select the source display field. Note that the cur­sor will flash in the source field while its value is being edited.

3. With the cursor in the source display field flashing, set the source range to the low­est possible range for the value to be sourced using the up or down RANGE key.
For example, you should use the 10V source range to output a 10V source value.
With a 10V source value and the 10V range selected, the source field display will
appear as follows:

Vsrc:+10.0000V

1-8 Performance Verification Model 2440 5A SourceMeter® Service Manual

4. With the source field cursor flashing, set the source output to the required value
using either:

• The SOURCE adjustment and left and right arrow keys.

• The numeric keys.

5. Note that the source output value will be updated immediately; you need not press
ENTER when setting the source value.

Setting the measurement range

When simultaneously sourcing and measuring either voltage or current, the measure range
is coupled to the source range, and you cannot independently control the measure range.
Thus, it is not necessary for you to set the measure range when testing voltage or current
measurement accuracy.

Compliance considerations

Compliance limits

When sourcing voltage, you can set the SourceMeter to limit current from 10nA to 5.25A.
Conversely, when sourcing current, you can set the SourceMeter to limit voltage from

0.2mV to 42V. The SourceMeter output will not exceed the programmed compliance
limit.

Types of compliance

There are two types of compliance that can occur: “real” and “range.” Depending on
which value is lower, the output will clamp at either the displayed compliance setting
(“real”) or at the maximum measurement range reading (“range”).

The “real” compliance condition can occur when the compliance setting is less than the
highest possible reading of the measurement range. When in compliance, the source out
put clamps at the displayed compliance value. For example, if the compliance voltage is
set to 1V and the measurement range is 2V, the output voltage will clamp (limit) at 1V.

“Range” compliance can occur when the compliance setting is higher than the possible
reading of the selected measurement range. When in compliance, the source output
clamps at the maximum measurement range reading (not the compliance value). For
example, if the compliance voltage is set to 1V and the measurement range is 200mV, the
output voltage will clamp (limit) at 210mV.

-

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-9

Maximum compliance values

The maximum compliance values for the measurement ranges are summarized in

Table 1-2.

Table 1-2

Maximum compliance values

Maximum

Measurement

range

200mV

2V
10V
40V

10μA

100μA

1mA

10mA

100mA

1A

5A

compliance

value

210mV

2.1V

10.5V
42V

10.5μA

105μA

1.05mA

10.5mA

105mA

1.05A

5.25A

Performance Verification

When the SourceMeter goes into compliance, the “Cmpl” label or the units label (i.e.,
“mA”) for the compliance display will flash.

Determining compliance limit

The relationships to determine which compliance is in effect are summarized as follows.
They assume that the measurement function is the same as the compliance function.

• Compliance Setting < Measurement Range = Real Compliance

• Measurement Range < Compliance Setting = Range Compliance

You can determine the compliance that is in effect by comparing the displayed compli­ance setting to the present measurement range. If the compliance setting is lower than the
maximum possible reading on the present measurement range, the compliance setting is
the compliance limit. If the compliance setting is higher than the measurement range, the
maximum reading on that measurement range is the compliance limit.

1-10 Performance Verification Model 2440 5A SourceMeter® Service Manual

Taking the SourceMeter out of compliance

Verification measurements should not be made when the SourceMeter is in compliance.
For purposes of the verification tests, the SourceMeter can be taken out of compliance by
going into the edit mode and increasing the compliance limit.

NOTE Do not take the unit out of compliance by decreasing the source value or chang-

ing the range. Always use the recommended range and source settings when
performing the verification tests.

Output voltage accuracy

Follow the steps below to verify that Model 2440 output voltage accuracy is within speci­fied limits. This test involves setting the output voltage to each full-range value and mea­suring the voltages with a precision digital multimeter.

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks, as shown in

Figure 1-1

Connections for voltage verification tests

Figure 1-1.

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

4- WIRE

INPUT/

SENSE

OUTPUT

HI

75V

PEAK

SWEEP

SOURCE

I

5

2440 5A SourceMeter

EDIT

EXIT ENTER

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

RANGE

AUTO

RANGE

®

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Model 2440

Input HI

Digital Multimeter

Input LO

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-11

2. Select the multimeter DC volts measuring function.

3. Set the voltage source protection to NONE. To do so, press CONFIG then
SOURCE V to access the CONFIGURE V-SOURCE menu. Select PROTEC
TION, and set the voltage source protection limit to NONE.

4. Press the Model 2440 SOURCE V key to source voltage, and make sure the source
output is turned on.

5. Verify output voltage accuracy for each of the voltages listed in Table 1-3. For
each test point:

• Select the correct source range.

• Set the Model 2440 output voltage to the indicated value.

• Verify that the multimeter reading is within the limits given in the table.

6. Repeat the procedure for negative output voltages with the same magnitudes as
those listed in

7. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-3

Output voltage accuracy limits

Model 2440

source range

200mV

2V
10V
40V

Table 1-3.

Model 2440 output

voltage setting

200.000mV

2.00000V

10.0000V

40.0000V

Output voltage limits

(1 year, 18°C-28°C)

199.360 to 200.640mV

1.99900 to 2.00100V

9.9968 to 10.0032V

39.9872 to 40.0128V

Performance Verification

-

1-12 Performance Verification Model 2440 5A SourceMeter® Service Manual

Voltage measurement accuracy

Follow the steps below to verify that Model 2440 voltage measurement accuracy is within
specified limits. The test involves setting the source voltage to full-range values, as mea
sured by a precision digital multimeter, and then verifying that the Model 2440 voltage
readings are within required limits.

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks , as shown in

2. Select the multimeter DC volts function.

3. Set the voltage source protection to NONE. To do so, press CONFIG then
SOURCE V to access the CONFIGURE V-SOURCE menu. Select PROTEC
TION, and set the voltage source protection limit to NONE.

4. Set the Model 2440 to both source and measure voltage by pressing the SOURCE
V and MEAS V keys, and make sure the source output is turned on.

5. Verify output voltage accuracy for each of the voltages listed in Table 1-4. For
each test point:

• Select the correct source range.

• Set the Model 2440 output voltage to the indicated value as measured by the
digital multimeter.

• Verify that the Model 2440 voltage reading is within the limits given in the
table.

Figure 1-1.

-

-

NOTE It may not be possible to set the voltage source to the specified value. Use the

closest possible setting, and modify reading limits accordingly.

6. Repeat the procedure for negative source voltages with the same magnitudes as
those listed in

7. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-4

Voltage measurement accuracy limits

Model 2440 source

and measure

range*

200mV

2V
10V
40V

Table 1-4.

Source voltage*

200.000mV

10.0000V

40.0000V

2.00000V

Model 2440 voltage reading

limits (1 year, 18°C-28°C)

199.676 to 200.324mV

1.99946 to 2.00054V

9.9978 to 10.0022V

39.991 to 40.009V

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-13

Table 1-4

Voltage measurement accuracy limits

Model 2440 source

and measure

range* Source voltage*

* Measure range coupled to source range when simultaneously sourcing and measuring voltage.

** As measured by precision digital multimeter. Use closest possible value, and modify reading lim-

its accordingly if necessary.

Output current accuracy

Follow the steps below to verify that Model 2440 output current accuracy is within speci­fied limits. The test involves setting the output current to each full-range value and mea­suring the currents with a precision digital multimeter.

10μA to 1A range accuracy

1. With the power off, connect the digital multimeter to the Model 2440 INPUT/
OUTPUT jacks, as shown in

Figure 1-2

Connections for 10μA to 1A range current verification tests

V

LOCAL

67

DIGITS SPEED

MEAS

I

Ω

1

230

REL

FILTER

89

RECALL

STORE

EDIT

DISPLAY

TOGGLE

POWER

Performance Verification

Model 2440 voltage reading

limits (1 year, 18°C-28°C)

Figure 1-2.

4- WIRE

INPUT/

SENSE

OUTPUT

HI

75V

PEAK

RANGE

AUTO

RANGE

®

2440 5A SourceMeter

V

4

TRIG

SWEEP

+/-

CONFIG MENU

I

5

SOURCE

EDIT

EXIT ENTER

FCTN

LIMIT

ON/OFF

OUTPUT

75V

5V

PEAK

PEAK

LO

250V
PEAK

TERMINALS

FRONT/

REAR

Model 2440

Digital Multimeter

2. Select the multimeter DC current measuring function.

Input LO

Amps

1-14 Performance Verification Model 2440 5A SourceMeter® Service Manual

3. Press the Model 2440 SOURCE I key to source current, and make sure the source
output is turned on.

4. Verify output current accuracy for the 10μA-1A range currents listed in Table 1-5.
For each test point:

• Select the correct source range.

• Set the Model 2440 output current to the correct value.

• Verify that the multimeter reading is within the limits given in the table.

5. Repeat the procedure for negative output currents with the same magnitudes as
those listed in

Table 1-5.

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

5A range accuracy

1. With the power off, connect the digital multimeter and the 1Ω resistor to the Model
2440 INPUT/OUTPUT jacks, as shown in

Figure 1-3

Connections for 5A range current verification tests

SWEEP

I

5

SOURCE

2440 5A SourceMeter

EDIT

EXIT ENTER

RANGE

AUTO

RANGE

EDIT

DISPLAY

TOGGLE

POWER

V

LOCAL

67

DIGITS SPEED

MEAS

FCTN

I

Ω

230

FILTER

89

STORE

LIMIT

RECALL

V

4

TRIG

+/-

CONFIG MENU

1

REL

4- WIRE

SENSE

HI

75V

5V

PEAK

PEAK

®

LO

ON/OFF

OUTPUT

INPUT/

OUTPUT

TERMINALS

FRONT/

REAR

Figure 1-3.

75V
PEAK

250V
PEAK

Model 2440

Digital Multimeter

1Ω Resistor

Input HI

Input LO

Model 2440 5A SourceMeter® Service Manual Performance Verification 1-15

2. Select the multimeter DC volts measuring function.

3. Press the Model 2440 SOURCE I key to source current, and make sure the source
output is turned on.

4. Verify output current accuracy for the 5A range. Be sure to:

• Select the 5A source range.

• Set the Model 2440 output current to the correct 5A output value.

• Verify that the multimeter reading is within the 5A range limits given in Table

1-5.

(Since the value of the 1Ω resistor value is assumed to be the same as its nominal
value, the DMM voltage reading is the same as the sourced current.)

5. Repeat the procedure for a negative 5A current output value.

6. Repeat the entire procedure using the rear panel INPUT/OUTPUT jacks. Be sure to
select the rear panel jacks with the front panel TERMINALS key.

Table 1-5

Output current accuracy limits

Model 2440

source range

10μA

100μA

1mA

10mA

100mA

1A
5A*

Model 2440

output current setting

10.0000μA

100.000μA

1.00000mA

10.0000mA

100.000mA

1.00000A

5.00000A

Output current limits

(1 year, 18°C-28°C)

9.9947 to 10.0053μA

99.949 to 100.051μA

0.99946 to 1.00054mA

9.9935 to 10.0065mA

99.914 to 100.086mA

0.99843 to 1.00157A

4.9896 to 5.0104A

Performance Verification

*See separate procedure for 5A range. DMM voltage reading is same as sourced current.