Keithley 2440, 2430, 2425, 2420, 2410 User Manual

Model 2400 Series SourceMeter

Quick Results Guide

®

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 1 year 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 defecti ve.
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-rechar geable
batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUD­ING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.
THE REMEDIES 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.

Sales Offices: BELGIUM: Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02-363 00 40 • Fax: [phone]

CHINA: Y uan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: [phone]
FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: [phone] • Fax: [phone]
FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: Flat 2B, Willocrissa • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
ITALY: Viale San Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: [phone]
JAPAN: New Pier T akeshiba North T o wer 13F • 11-1, Kaigan 1-chome • Minato-ku, Tokyo 105-0022 • 81-3-5733-7555 • Fax: [phone]
KOREA: 2FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-888 • 82-2-574-7778 • Fax: [phone]
NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 679 • F ax: 08-655 26 10
SWITZERLAND: Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: [phone]
TAIWAN: 1FL., 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077 • Fax: [phone]

28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: [phone]

1-888-KEITHLEY (534-8453) • www.keithley.com

4/02

2400 Series SourceMeter

Quick Results Guide

®

©2000, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Third Printing, May 2002

Document Number: 2400S-903-01 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 Re vision of the manual. Each new Re vision includes
a revised copy of this print history page.

Revision A (Document Number 2400S-903-01)........................................................February 2000

Revision B (Document Number 2400S-903-01)..............................................................April 2001

Revision C (Document Number 2400S-903-01)...............................................................May 2002

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.

S

afety 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 manual for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product may be impaired.
The types of product users are:

Responsible body

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

Operators

instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel

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

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 Cate gory II connections require protection for high transient over -voltages often associated with
local A C 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 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 v oltage le vels greater than 30V RMS,

42.4V peak, or 60VDC are present.

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,

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.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under
test. ALWAYS remo ve power from the entire test system and discharge any capacitors before: connecting or disconnecting ca-

is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equip-

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

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

are trained to work on live circuits, and perform safe installations and repairs of products. Only properly

A good safety practice is to expect that hazardous voltage is present in any unknown

no conductive part of the circuit may be exposed.

5/02

bles 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. Al-

ways 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 in-

formation, 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 or 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 avoid personal contact with these voltages.

The

WARNING

information very carefully before performing the indicated procedure.
The

CAUTION

ranty.
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. Al ways read the associated

heading in a manual explains hazards that could damage the instrument. Such damage may in v alidate the war -

Table of Contents

Introduction ................................................................................... 1

Source-measure capabilities .......................................................... 1

Front and rear panels ..................................................................... 3

Navigating menus and entering numeric data ............................... 4

Menu navigation .................................................................... 4

Numeric data entry (EDIT keys) ............................................ 4

Editing source and compliance values .......................................... 4

Editing keys ........................................................................... 4

Editing procedure ................................................................... 5

Toggling the source and measure display fields ..................... 5

Basic connections .......................................................................... 5

Front/rear terminals selection ................................................ 6

2-wire connections ................................................................. 6

4-wire connections ................................................................. 7

Cable guard ............................................................................ 8

Ohms guard ............................................................................ 8

Remote command programming .......................................... 10

Basic SourceMeter operations .................................................... 10

Source-measure .................................................................... 10

Measure only (V or I) .......................................................... 12

Measure ohms ...................................................................... 13

Remote command programming .......................................... 15

Settings to optimize performance ............................................... 19

Range ................................................................................... 19

Speed .................................................................................... 19

Digits .................................................................................... 20

Filter ..................................................................................... 20

Rel (nulling offsets) ............................................................. 21

Remote command programming .......................................... 22

Features to enhance DUT testing ................................................ 23

Data store ............................................................................. 23

Sweep operation ................................................................... 25

Performing sweeps ............................................................... 29

Limit testing ......................................................................... 34

Math functions ..................................................................... 36

Pulse mode (Model 2430 only) ............................................ 40

List of Illustrations

Figure 1 Front panel ................................................................................ 3

Figure 2 Rear panel .................................................................................. 3

Figure 3 2-wire connections .................................................................... 6

Figure 4 4-wire connections .................................................................... 7

Figure 5 Cable guard connections ........................................................... 8

Figure 6 Guarded ohms measurements ................................................... 9

Figure 7 Linear staircase sweep ............................................................. 25

Figure 8 Logarithmic staircase sweep (example) .................................. 26

Figure 9 Custom pulse sweep (example) ............................................... 27

Figure 10 Pulse-measure timing .............................................................. 40

List of Tables

Table 1 SCPI commands; terminals, sense, and cable guard ............... 10

Table 2 Source-measure procedure ...................................................... 11

Table 3 Measure only (V or I) procedure ............................................. 12

Table 4 Auto ohms measurement procedure ........................................ 13

Table 5 Manual ohms measurement procedure .................................... 14

Table 6 SCPI commands; source-measure and measure only............... 16

Table 7 SCPI commands; measure ohms ............................................. 16

Table 8 Command sequence for source-measure example .................. 17

Table 9 Command sequence for measure current only example .......... 17

Table 10 Command sequence for auto ohms example ........................... 18

Table 11 Command sequence for manual ohms example ...................... 18

Table 12 SCPI commands; speed, digits, filter, and rel .......................... 22

Table 13 SCPI commands; data store .................................................... 24

Table 14 Command sequence for data store example ............................ 24

Table 15 SCPI commands; sweeping ..................................................... 31

Table 16 Command sequences for sweep examples .............................. 32

Table 17 SCPI commands; basic non-binning limit testing ................... 35

Table 18 Command sequence for Limit 2 test example ......................... 36

Table 19 SCPI commands; built-in math functions ............................... 39

Table 20 Command sequence for power measurement example ........... 39

Table 21 SCPI commands; select and configure Pulse Mode ................ 44

Table 22 Command sequence for Pulse Mode example ........................ 44

Introduction

This guide is designed to familiarize users with fundamental operation (front panel and
remote) of the Keithley 2400 Series SourceMeters. For comprehensive information on all
aspects of SourceMeter operation, refer to the 2400 Series SourceMeter User’s Manual.

Operation information in this guide is divided into four parts; (1) Fundamental source­measure operations, (2) Settings to optimize performance, (3) Features to enhance DUT testing
and (4) More testing techniques. This format allows a new user to easily progress from basic
simple operation to more complex procedures.

2400 Series

SourceMeter

Quick Results Guide

Remote command programming

in this guide, the related SCPI commands for remote operation are summarized in tables. Most
commands have a query form. For e xample, :OUTPut ON turns the output on, while :OUTPut?
requests the present state of the output. Note that the SourceMeter must be addressed to talk
after sending a query command.

For operations where command sequence is important, programming examples are pro­vided. The exact programming syntax will depend on the test program language.

Source-measure capabilities

Model 2400:

• Source voltage from 5µV to 210V; measure voltage from 1µV to 211V.

• Source current from 50pA to 1.05A; measure current from 10pA to 1.055A.

• Measure resistance from 100µ

• Maximum source power is 22W.

- For the various SourceMeter operating modes covered

Ω

(<100µΩ in manual ohms) to 211MΩ.

2 Quick Results Guide

Model 2410:

• Source voltage from 5µV to 1100V; measure voltage from 1µV to 1100V.

• Source current from 50pA to 1.05A; measure current from 10pA to 1.055A.

• Measure resistance from 100µ

• Maximum source power is 22W.

Model 2420:

• Source voltage from 5µV to 63V; measure voltage from 1µV to 63.3V.

• Source current from 500pA to 3.15A; measure current from 100pA to 3.165A.

• Measure resistance from 10µ

• Maximum source power is 66W.

Model 2425:

• Source voltage from 5µV to 105V; measure voltage from 1µV to 105.5V.

• Source current from 500pA to 3.15A; measure current from 100pA to 3.165A.

• Measure resistance from 10µ

• Maximum source power is 110W.

Ω

(<100µΩ in manual ohms) to 211MΩ.

Ω

(<10µΩ in manual ohms) to 21.1MΩ.

Ω

(<10µΩ in manual ohms) to 21.1MΩ.

Model 2430:

• Source DC or pulse voltage from 5µV to 105V; measure voltage from 1µV to 105.5V.

• Source DC current from 500pA to 3.15A; measure DC current from 100pA to 3.165A.

• Source pulse current from 500pA to 10.5A; measure pulse current from 100pA to

10.55A.

Ω

• Measure resistance from 10µ

(<10µΩ in manual ohms) to 21.1MΩ.

• Maximum DC source power is 110W.

• Maximum pulse source power is 1.1kW.

Model 2440:

• Source voltage from 5µV to 42V; measure voltage from 1µV to 42V.

• Source current from 500pA to 5.25A; measure current from 100pA to 5.25A.

• Measure resistance from 10µ

Ω (< 10µΩ

in manual ohms) to 21.1 MΩ.

• Maximum source power is 55W.

Front and rear panels

WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

CAUTION: FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE FUSE WITH SAME TYPE AND RATING.

The front and rear panels of the Model 2400 SourceMeter are shown in Figures 1 and 2. The
front and rear panels of the other SourceMeter models are similar . The use of the v arious instru­ment controls and connectors will be explained throughout this guide.

Quick Results Guide 3

Figure 1

Front panel

Figure 2

Rear panel

EDIT

DISPLAY

TOGGLE

POWER

250V

PEAK

4-WIRE

SENSE

WITH FRONT PANEL MENU)

V

LOCAL

67

DIGITS SPEED

HI

5V

PEAK

LO

INPUT/

OUTPUT

!

IEEE-488

(ENTER IEEE ADDRESS

250V
PEAK

4-WIRE

INPUT/

SENSE

OUTPUT

HI

250V
PEAK

2400 SourceMeter

MEAS

250V
PEAK

Ω

230

FILTER

89

RECALL

STORE

GUARD

5V

PEAK

GUARD

SENSE

CAT I

FCTN

LIMIT

V, Ω,

I

1

REL

5V
PK

V

4

TRIG

+/-

CONFIG MENU

RS-232

5

SWEEP

SOURCE

I

EDIT

EXIT ENTER

TRIGGER

LINK

MADE IN

U.S.A.

RANGE

AUTO

RANGE

LINE FUSE

SLOWBLOW

2.5A, 250V

LINE RATING

100-240VAC

50, 60, Hz

190VA MAX.

FUSE DRAWER

ON/OFF

OUTPUT

PEAK

LO

5V

TERMINALS

FRONT/

REAR

OUTPUT
ENABLE

250V

PEAK

250V
PEAK

U

CUS

L

LISTED

SourceMeter

4ZA4

4 Quick Results Guide

Navigating menus and entering numeric data

Menu navigation

Many operating modes for the SourceMeter are configured using front panel menus.
Throughout this guide, menu navigation will be presented as a sequence of key presses and
menu item selections. For example, the follo wing sequence selects the auto ohms source mode:

Press CONFIG > press MEAS

The above sequence is explained as follows:

1. Press the CONFIG key.

2. Press the MEAS

3. Select the SOURCE menu item.

4. Select the AUTO ohms source mode.

A menu item is selected by placing the cursor on it and pressing the ENTER key. The



keys control cursor position.

Ω

key.

Ω

> select SOURCE > select AUTO

Numeric data entry (EDIT keys)

Numeric values must to be entered for some menu items. Numeric entry is also used to set
source and compliance values. The edit k eys for numeric entry include the EDIT
to control cursor position, EDIT
the number keys.

After a value is keyed in, press ENTER to select it. Note that pressing MENU resets a dis­played number to its minimum value.





and

keys to increment or decrement the digit value, and

Editing source and compliance values

Editing keys



and





and

keys

Use the following keys to edit source and compliance values:

• DISPLAY EDIT — Selects the source or compliance display field for editing. A blink­ing cursor will appear in the field to be edited. If no key is pressed within a fe w seconds,
the edit mode will be cancelled automatically.



• EDIT

• SOURCE
that pressing either of these keys will automatically enable the source edit mode.

• RANGE

• Numeric keys (0-9) — Allow you to directly enter source or compliance values.

• EXIT — Exits the edit mode without waiting for the time-out period.



and

— Places the display cursor on the display digit to be changed.



or  — Increments or decrements the source or compliance value. Note



or  — Selects the source or compliance range.

Editing procedure

1. Press the DISPLAY EDIT key to place the blinking cursor in either the source or com­pliance display field to be edited.



2. If desired, use the RANGE
range.

3. To simply increment or decrement the display value, use the EDIT
place the blinking cursor on the digit to be changed, then increment or decrement the
value with the SOURCE
be updated immediately; you need not press ENTER to complete the process.

4. To enter the source or compliance value directly, simply key in the desired value with
the numeric keys while the cursor is blinking. Again, the source or compliance value
will be updated immediately.

and  keys to select the desired source or compliance



and  keys. Note that the source or compliance value will

Toggling the source and measure display fields

Normally, the measured reading value will appear in the upper, main display line, while the
source and compliance values will appear in the left and right fields respectively of the lower
display line. You can toggle the source and measure display fields by pressing the DISPLAY
TOGGLE key to place the source and measure values in the desired display fields.

Quick Results Guide 5





and

keys to

Basic connections

WARNING

The three basic connection configurations for the SourceMeter include 2-wire local sensing,
4-wire remote sensing, and cable guard.

NOTE

Connections and details for in-circuit ohms measur ements (ohms guard) are co ver ed
in the “Advanced operation” section of this guide.

The SourceMeter uses safety jacks for signal connections. To avoid
electric shock:

• Do not leave exposed connections.

• Properly insulate all external circuits.

• The front and rear terminals of the SourceMeters are rated for connec­tion to circuits rated Installation Category I only. Do not connect the
SourceMeter terminals to CAT II, CAT III, or CAT IV circuits. Connec­tion of the SourceMeter Input/Output terminals, to circuits higher than
CAT I, can cause damage to the equipment or expose the operator to
hazardous voltages.

• Hazardous voltages may be present on the output and guard terminals.
To prevent electrical shock that could cause injury or death, NEVER
make or break connections to the SourceMeter while the unit is on.
Power off the equipment from the front panel or disconnect the main
power cord from the rear of the SourceMeter before handling cables
connected to the outputs. Putting the equipment into standby mode
does not guarantee the outputs are not powered if a hardware or soft­ware fault occurs.

6 Quick Results Guide

Front/rear terminals selection

The input/output and sense terminals are accessible from both the front and rear panels,
while the guard terminals and chassis ground are only accessible from the rear panel. On the
front panel, press the FRONT/REAR ke y to toggle between front and rear. The REAR annunci­ator indicates that the rear terminals are selected. With REAR off, the front terminals are
selected.

2-wire connections

Connections for 2-wire local sensing are shown in Figure 3. The following menu sequence
selects 2-wire local sensing:

Figure 3

2-wire connections

Press CONFIG > select SOURCE V (or

4-WIRE

SENSE

ON/OFF

OUTPUT

SourceMeter Front Panel

HI

LO

INPUT/

OUTPUT

TERMINALS

FRONT/

FRONT/

REAR

REAR

ΜΕΑS Ω

) > select SENSE MODE > select 2-WIRE

DUT

Sense Selection: 2-wire

4-wire connections

Connections for 4-wire local sensing are shown in Figure 4. Use 4-wire remote sensing for

the following source-measure conditions:

Quick Results Guide 7

•Test circuit impedance is <1k

• Optimum ohms, V-source, and/or V-measure accuracy is required.

With 4-wire sensing selected, the 4W annunciator is on. The following menu sequence

selects 4-wire remote sensing:

Press CONFIG > select SOURCE V (or MEAS

NOTE

Specified accuracies for both source and measure are achieved only using 4-wire
remote sensing.

Ω

.

Ω

) > select SENSE MODE > select 4-WIRE

8 Quick Results Guide

WARNING:NO INTERNAL OPERATOR SERVICAB

CAUTION:FOR CONTINUED PROTECTION AGAINST FIR

Cable guard

When testing high-impedance DUT (>1GΩ), cable guard is used to drive the shields of
cables and test fixtures to minimize leakage currents and input capacitance. A typical connec­tion scheme using cable guard is shown in Figure 5. The following menu sequence selects
cable guard:

Press CONFIG > press SOURCE V (or SOURCE I or MEAS
CABLE

The guard terminal of the SourceMeter is at virtually the same potential as input/output HI.
Therefore, if there is hazardous voltage at input/output HI, it is also present on the guard shield
for the test circuit.

WARNING

Figure 5

Cable guard connections

Ω

) > select GUARD > select

To prevent injury from electric shock, the guard shield must be enclosed in
a safety shield (i.e., test fixture) that is connected to safety earth ground (as
shown in Figure 5).

Guard Shield

DUT

4-WIRE

SENSE

Test Fixture

HI

LO

INPUT/

OUTPUT

Connect to earth safety ground
using #18 AWG wire or larger.

V, Ω

GUARD

GUARD
SENSE

Ohms guard

Ohms guard allows in-circuit resistance measurements on DUT where other parasitic leak­age devices are present. Connection schemes for a Delta DUT configuration is shown in
Figure 6.

IEEE-488

(ENTER IEEE ADDRESS

WITH FRONT PANEL MENU)

RS232