Model 6521Low Current
Model 6522Voltage/Current
Scanner Cards
Instruction 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 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 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 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.
BELGIUM: Keithley Instruments B.V.
CHINA: Keithley Instruments China
FRANCE: Keithley Instruments Sarl
GERMANY: Keithley Instruments GmbH
GREAT BRITAIN: Keithley Instruments Ltd
INDIA: Keithley Instruments GmbH
ITALY: Keithley Instruments s.r.l.
NETHERLANDS: Keithley Instruments B.V.
SWITZERLAND: Keithley Instruments SA
TAIWAN: Keithley Instruments Taiwan
• 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: 440-248-6168 • http://www.keithley.com
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9/00
Model 6521 Low Current Scanner Card
Model 6522 Voltage/Current Scanner Card
Instruction Manual
©1994, Keithley Instruments, Inc.
All rights reserved.
Cleveland, Ohio, U.S.A.
Second Printing, April 2001
Document Number: 6521-901-01 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 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 Revision is created, all Addenda associated with the
previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes a
revised copy of this print history page.
Revision A (Document Number 6521-901-01).............................................................................. September 1994
Addendum A (Document Number 6521-901-02)........................................................................... December 1995
Revision B (Document Number 6521-901-01)....................................................................................... April 2001
All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product 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
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
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
to keep it operating, for example, 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
safe installations and repairs of products. 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-voltages 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.
is the individual or group responsible for the use
use the product for its intended function. They must be
perform routine procedures on the product
are trained to work on live circuits, and perform
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.
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,
exposed.
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 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.
A good safety practice is to expect
no conductive part of the circuit may be
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
avoid personal contact with these voltages.
The
WARNING
result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.
The
CAUTION
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, 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
heading in a manual explains hazards that could
2/01
CHANNELS PER CARD: 10.
FUNCTIONS: Amps.
CONTACT CONFIGURATION:
Current Mode: Single pole break-before-make for signal HI input. Signal
LO is common for all 10 channels and output. When a channel is off,
signal HI is connected to signal LO via a relay. All channels connect to
signal LO, in a make-before-break configuration between channel closures so that the current path is never interrupted.
All relays open when power is off.
SCAN SPEED:
1.5 channels/second with default settings.
1, 2
43 channels/second maximum speed.
1, 2, 3
1
When used with 6517 Electrometer.
2
Scan speeds are for fixed range readings for 200V and 20mA 6517
ranges, into data buffer.
3
6517 Filter off, speed fast, settling time 0 seconds.
CONNECTOR TYPE: Inputs BNC, Outputs Triaxial.
SIGNAL LEVEL: 30V, 500mA, 10VA (resistive load).
CONTACT LIFE: >10
6
closures at maximum signal level; >107closures at
low signal levels.
CONTACT RESISTANCE: <1Ω.
CONTACT POTENTIAL: <200µV.
OFFSET CURRENT: <1pA (<30fA typical at 23°C, <60% RH).
ACTUATION TIME: 2ms.
COMMON MODE VOLTAGE: < 30V peak.
ENVIRONMENT:
Operating: 0°C to 50°C up to 35°C at 70% RH.
Storage: –25°C to 65°C.
DIMENSIONS,WEIGHT: 38mm high ×70mm wide × 242mm deep (1.5 in
× 2.75 in ×9.5 in). Net weight 623g (22 oz).
Specifications are subject to change without notice.
Model 6521 Low Current Scanner
OUTHL
H
IN 2...9
G
IN 1
L
H
IN 10
L
CHANNELS PER CARD: 10.
FUNCTIONS: Volts, Amps.
CONTACT CONFIGURATION:
Voltage Mode: Single pole break-before-make for signal HI input. Guard
is common for all 10 channels and output.
Current Mode: Single pole break-before-make for signal HI input. Signal
LO is common for all 10 channels and output. When a channel is off,
signal HI input is connected to signal LO via a relay. All channels connect to signal LO in a make-before-break configuration between
channel closures so that the current path is never interrupted.
All relays open when power is off.
SCAN SPEED:
1.5 channels/second with default settings.
1, 2
43 channels/second maximum speed.
1, 2, 3
1
When used with 6517 Electrometer.
2
Scan speeds are for fixed range readings for 200V and 20mA 6517
ranges, into data buffer.
3
6517 Filter off, speed fast, settling time 0 seconds.
CONNECTOR TYPE: Inputs: Triaxial. Outputs: Triaxial.
SIGNAL LEVEL: 200V, 500mA, 10VA (resistive load).
CONTACT LIFE: >10
6
closures at maximum signal level; >107closures at
low signal levels.
CONTACT RESISTANCE: <1Ω.
CONTACT POTENTIAL: <200µV.
OFFSET CURRENT: <1pA (<30fA typical at 23°C, <60% RH).
CHANNEL ISOLATION: > 10
13
Ω, <0.3pF.
INPUT ISOLATION: >1010Ω, <125pF (Input HI to Input LO).
ACTUATION TIME: 2ms.
COMMON MODE VOLTAGE: <250V peak.
ENVIRONMENT:
Operating: 0°C to 50°C up to 35°C at 70% RH.
Storage: –25°C to 65°C.
DIMENSIONS,WEIGHT: 38mm high ×70mm wide × 242mm deep (1.5 in
× 2.75 in ×9.5 in). Net weight 623g (22 oz).
Specifications are subject to change without notice.
Model 6522 Low Current/Voltage Scanner
OUTHL
H
IN 2...9
G
IN 1
L
G
H
IN 10
L
G
Table of Contents
1 General Information
1.1 Introduction........................................................................................................................................................ 1-1
1.2 Features .............................................................................................................................................................. 1-1
1.2.1 Model 6521 features................................................................................................................................... 1-1
1.2.2 Model 6522 features................................................................................................................................... 1-1
1.3 Warranty information......................................................................................................................................... 1-1
1.4 Manual addenda ................................................................................................................................................. 1-2
1.5 Safety symbols and terms .................................................................................................................................. 1-2
1.6 Specifications ..................................................................................................................................................... 1-2
1.7 Unpacking and inspection.................................................................................................................................. 1-2
1.7.1 Inspection for damage................................................................................................................................ 1-2
1.7.2 Handling precautions ................................................................................................................................. 1-2
1.7.3 Shipment contents ...................................................................................................................................... 1-2
1.7.4 Instruction manual...................................................................................................................................... 1-2
1.8 Repacking for shipment ..................................................................................................................................... 1-2
1.9 Optional accessories........................................................................................................................................... 1-2
1.9.1 Model 6521 accessories ............................................................................................................................. 1-2
1.9.2 Model 6522 accessories ............................................................................................................................. 1-3
2 Card Connections and Installation
2.1 Introduction........................................................................................................................................................ 2-1
2.2 Handling precautions ......................................................................................................................................... 2-1
2.3 Connections........................................................................................................................................................ 2-1
2.3.1 Model 6521 scanner card configuration..................................................................................................... 2-1
2.3.2 Model 6522 scanner card configuration..................................................................................................... 2-2
2.3.3 Input connections ....................................................................................................................................... 2-3
2.3.4 Output connections .................................................................................................................................... 2-3
2.3.5 Typical connecting schemes ...................................................................................................................... 2-3
2.3.6 Guarded operation...................................................................................................................................... 2-4
2.4 Card installation and removal ............................................................................................................................ 2-4
2.4.1 Scanner card installation ............................................................................................................................ 2-5
2.4.2 Output connections to electrometer ........................................................................................................... 2-7
2.4.3 Scanner card removal................................................................................................................................. 2-7
i
3 Operation
3.1 Introduction ........................................................................................................................................................ 3-1
3.2 Signal limitations................................................................................................................................................ 3-1
3.2.1 Model 6521 signal limitations .................................................................................................................... 3-1
3.2.2 Model 6522 signal limitations .................................................................................................................... 3-1
3.2.3 Relay operation........................................................................................................................................... 3-2
3.3 Scanner card detection........................................................................................................................................ 3-2
3.3.1 Power-up detection..................................................................................................................................... 3-2
3.3.2 Scanner option bus query ........................................................................................................................... 3-2
3.4 Front panel operation.......................................................................................................................................... 3-2
3.4.1 Scanning controls ....................................................................................................................................... 3-2
3.4.2 Scan control and configuration menus ....................................................................................................... 3-2
3.4.3 Closing and opening channels .................................................................................................................... 3-3
3.4.4 Card configuration...................................................................................................................................... 3-4
3.4.5 Scanning procedure .................................................................................................................................... 3-5
3.5 IEEE-488 bus operation ..................................................................................................................................... 3-5
3.5.1 IEEE-488 bus scanner commands .............................................................................................................. 3-5
3.5.2 Closing and opening channels .................................................................................................................... 3-6
3.5.3 Card configuration...................................................................................................................................... 3-7
3.5.4 Bus scanning............................................................................................................................................... 3-7
3.6 Measurement considerations .............................................................................................................................. 3-7
3.6.1 Generated currents...................................................................................................................................... 3-7
3.6.2 Path isolation .............................................................................................................................................. 3-8
3.6.3 Noise........................................................................................................................................................... 3-9
3.6.4 Keeping connectors clean......................................................................................................................... 3-10
3.6.5 Guarded operation .................................................................................................................................... 3-10
3.6.6 Voltage/current scan mode ....................................................................................................................... 3-10
3.7 Typical applications.......................................................................................................................................... 3-11
3.7.1 Capacitor leakage measurements ............................................................................................................. 3-11
3.7.2 High-resistance measurements ................................................................................................................. 3-12
3.7.3 Low-current measurements ...................................................................................................................... 3-12
4 Service Information
4.1 Introduction ........................................................................................................................................................ 4-1
4.2 Handling and cleaning precautions .................................................................................................................... 4-1
4.2.1 Handling precautions.................................................................................................................................. 4-1
4.2.2 Soldering considerations ............................................................................................................................ 4-1
4.3 Performance verification .................................................................................................................................... 4-2
4.3.1 Environmental conditions........................................................................................................................... 4-2
4.3.2 Recommended verification equipment....................................................................................................... 4-2
4.3.3 Scanner card connections ........................................................................................................................... 4-2
4.3.4 Offset current tests...................................................................................................................................... 4-3
4.3.5 Signal path contact resistance tests............................................................................................................. 4-4
4.3.6 Ground relay contact resistance tests ......................................................................................................... 4-5
4.3.7 Isolation tests .............................................................................................................................................. 4-6
4.4 Special handling of static-sensitive devices ....................................................................................................... 4-8
4.5 Principles of operation........................................................................................................................................ 4-8
4.5.1 Block diagram ............................................................................................................................................ 4-8
4.5.2 Relay control .............................................................................................................................................. 4-8
4.5.3 Switching circuits ....................................................................................................................................... 4-8
4.5.4 Power-on/power-off safeguard................................................................................................................... 4-8
4.6 Troubleshooting.................................................................................................................................................. 4-9
ii
4.6.1 Troubleshooting equipment ....................................................................................................................... 4-9
4.6.2 Troubleshooting access .............................................................................................................................. 4-9
4.6.3 Troubleshooting procedure ........................................................................................................................ 4-9
5 Replaceable Parts
5.1 Introduction........................................................................................................................................................ 5-1
5.2 Parts lists ............................................................................................................................................................ 5-1
5.3 Ordering information ......................................................................................................................................... 5-1
5.4 Factory service ................................................................................................................................................... 5-1
5.5 Component layouts and schematic diagrams ..................................................................................................... 5-1
iii
iv
List of Illustrations
2 Card Connections and Installation
Figure 2-1 Model 6521 simplified schematic ............................................................................................................... 2-2
Figure 2-2 Model 6521 connecting cables.................................................................................................................... 2-2
Figure 2-3 Model 6522 simplified schematic ............................................................................................................... 2-2
Figure 2-4 Model 6522 connecting cables.................................................................................................................... 2-3
Figure 2-5 Typical amps function connections............................................................................................................. 2-3
Figure 2-6 Typical volts function connections ............................................................................................................. 2-3
Figure 2-7 Typical ohms function connections ............................................................................................................ 2-4
Figure 2-8 Typical coulombs function connections ..................................................................................................... 2-4
Figure 2-9 Typical guarded volts connections (Model 6522 only)............................................................................... 2-5
Figure 2-10 Scanner card installation ............................................................................................................................. 2-6
Figure 2-11 Output connections ..................................................................................................................................... 2-7
3 Operation
Figure 3-1 Path isolation resistance .............................................................................................................................. 3-8
Figure 3-2 Voltage attenuation by path isolation resistance......................................................................................... 3-9
Figure 3-3 Power line ground loops ............................................................................................................................. 3-9
Figure 3-4 Eliminating ground loops.......................................................................................................................... 3-10
Figure 3-5 Guarded operation..................................................................................................................................... 3-10
Figure 3-6 Capacitor leakage test system ................................................................................................................... 3-11
Figure 3-7 High-resistance test system....................................................................................................................... 3-12
Figure 3-8 Low-current test system ............................................................................................................................ 3-13
4 Service Information
Figure 4-1 Connections for offset current verification ................................................................................................. 4-3
Figure 4-2 Connections for signal path contact resistance tests ................................................................................... 4-4
Figure 4-3 Connections for ground relay contact resistance tests ................................................................................ 4-5
Figure 4-4 Connections for channel isolation............................................................................................................... 4-7
Figure 4-5 Connections for input isolation ................................................................................................................... 4-7
Figure 4-6 Block diagram ............................................................................................................................................. 4-8
v
vi
List of Tables
3 Operation
Table 3-1 Scan control menu...................................................................................................................................... 3-3
Table 3-2 Card configuration menu ........................................................................................................................... 3-3
Table 3-3 Summary of IEEE-488 bus scanner commands......................................................................................... 3-6
4 Service Information
Table 4-1 Recommended verification equipment ...................................................................................................... 4-2
Table 4-2 Recommended troubleshooting equipment................................................................................................ 4-9
Table 4-3 Troubleshooting procedure ...................................................................................................................... 4-10
vii
viii
1
General Information
1.1 Introduction
This section contains general information about the Models
6521 and 6522 scanner card options for the Model 6517
Electrometer. Both cards provide 10 channels of single-pole
switching. The Model 6521 is intended for use primarily
with the amps function, while the Model 6522 can be used
with the volts, amps, ohms, and charge functions. Both cards
have very low offset current and are designed for installation
in the Model 6517 rear panel OPTION SLOT.
Section 1 is arranged in the following manner:
1.2 Features
1.3 Warranty information
1.4 Manual addenda
1.5 Safety symbols and terms
1.6 Specifications
1.7 Unpacking and inspection
1.8 Repacking for shipment
1.9 Optional accessories
• BNC input cables and a triax output cable to maintain
signal integrity.
• Low offset current (<1pA; <30fA typical).
1.2.2 Model 6522 features
Key Model 6522 features include:
• 10 channels of single-pole switching designed for volts,
ohms, amps and coulombs functions.
• When configured for current operation, input HI is connected to input LO when a channel is off for true current
switching.
• Triax input cables and a triax output cable to maintain
signal integrity.
• Low offset current (<1pA; <30fA typical).
• High channel isolation and input isolation.
• Fully guarded operation is supported to maintain signal
integrity under high-impedance voltage measurement
conditions.
1.2 Features
1.2.1 Model 6521 features
Key Model 6521 features include:
• 10 channels of single-pole switching designed for
amps.
• Input HI is connected to input LO when a channel is off
for true current switching.
1.3 Warranty information
Warranty information is located on the inside front cover of
this instruction manual. Should your Model 6521/22 require
warranty service, contact the Keithley representative or
authorized repair facility in your area for further
information. When returning the scanner card for repair, be
sure to fill out and include the service form at the back of this
manual in order to provide the repair facility with the
necessary information.
1-1
General Information
1.4 Manual addenda
Any improvements or changes concerning the scanner card
or manual will be explained in an addendum included with
the card. Addenda are provided in a page replacement format. Simply replace the obsolete pages with the new pages.
1.5 Safety symbols and terms
The following symbols and terms may be found on an instrument or used in this manual.
The symbol on an instrument indicates that the user
should refer to the operating instructions located in the instruction manual.
The WARNING heading used in this manual 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 used in this manual explains hazards that could damage the scanner card. Such damage may
invalidate the warranty.
!
• After removing the card from its anti-static bag, inspect
it for any obvious signs of physical damage. Report any
such damage to the shipping agent immediately.
• When the card is not installed in a Model 6517 Electrometer, keep the card in the anti-static bag, and store
it in the original packing carton.
1.7.3 Shipment contents
The following items are included with every Model 6521/22
order:
• Model 6521/22 Scanner Card
• Model 6521/22 Instruction Manual
• Input/output cables (factory connected to card)
• Additional accessories as ordered
1.7.4 Instruction manual
If an additional Model 6521/22 Instruction Manual is required, order the manual package, Keithley part number
6521-901-00. The manual package includes an instruction
manual and any pertinent addenda.
The symbol indicates a safety earth ground. The
ground screw must be secured to assure that the scanner card
is properly grounded.
1.6 Specifications
Model 6521/22 specifications are found at the front of this
manual. These specifications are exclusive of the Model
6517 Electrometer specifications.
1.7 Unpacking and inspection
1.7.1 Inspection for damage
The Model 6521/22 is packaged in a re-sealable, anti-static
bag to protect it from damage due to static discharge and
from contamination that could degrade its performance. Before removing the card from the bag, observe the precautions
on handling discussed below.
1.7.2 Handling precautions
• Always grasp the card by the side edges and covers. Do
not touch the board surfaces or components.
1.8 Repacking for shipment
Should it become necessary to return the Model 6521/22 for
repair, carefully pack the unit in its original packing carton
or the equivalent, and include the following information:
• Advise as to the warranty status of the scanner card.
• Write ATTENTION REPAIR DEPARTMENT on the
shipping label.
• Fill out and include the service form located at the back
of this manual.
1.9 Optional accessories
The following optional accessories are recommended for use
for the Model 6521/22.
1.9.1 Model 6521 accessories
Model 4801 Coax Cable: Low-noise coax cable, 1.2m (48
in) in length with male BNC connectors on each end. Recommended for extending Model 6521 input connections.
1-2
General Information
Model 4802-10 Coax Cable: 3m (10 ft.) of low-noise coax
cable with a male BNC connector on one end and unterminated at the other end. Recommended for extending Model
6521 input connections.
Model 4803 Low-Noise Cable Kit: Includes 15m (50 ft.) of
low-noise coax cable, 10 male BNC connectors, and five female BNC, chassis-mount connectors. Recommended for
extending Model 6521 input connections.
Model CAP-18 2-Slot Cap: Protective shield/cap for Model
6521 input jacks.
SC-9 Coax Cable: Low-noise coax cable without connectors
(sold by the foot).
1.9.2 Model 6522 accessories
Model 237-ALG Triax Cable: 2m (6.6.ft.) of low-noise triax
cable terminated with a 3-slot male triax connector on one
end, and three alligator clips on the other end. Recommended for extending Model 6522 input connections.
Model 6171 Adapter: 3-slot male to 2-lug female triax
adapter. Recommended for adapting 2-slot triax cables to
Model 6522 input connectors.
Model 7078-TRX-3 Triax Cable: 0.9m (3 ft.) low-noise tri-
ax cable terminated at both ends with 3-slot male triax connectors. Also available in 3m (10 ft.) and 6m (20 ft.) lengths
(Models 7078-TRX-10 and 7078-TRX-20 respectively).
Recommended for extending Model 6522 input connections.
Model 7078-TRX-BNC Adapter: 3-slot male triax to BNC
adapter useful for adapting BNC coax cables to Model 6522
input jacks.
Model 7078-TRX-TBC Triax Bulkhead Connector: 3-lug
female triax bulkhead connector with cap for assembly of
custom panels and interface connections.
Model CAP-31 3-Slot Cap: Protective shield/cap for Model
6522 input jacks.
SC-22 Triax Cable: Low-noise triax cable without connec-
tors (sold by the foot).
1-3
General Information
1-4
Figure 2-1
Model 6521 simplified schematic
2
Card Connections and Installation
2.1 Introduction
WARNING
The procedures in this section are intended only for qualified service personnel. Do not perform these procedures
unless you are qualified to do so. Failure
to recognize and observe normal safety
precautions could result in personal injury or death.
This section includes information on making connections to
the Model 6521/22 and on installing the card in the Model
6517 Electrometer. This section is arranged as follows:
2.2 Handling precautions: Explains precautions that must
be followed to prevent contamination to the scanner
card assembly. Contamination could degrade the performance of the scanner card.
2.3 Connections: Covers the basics for connecting external
circuitry to the scanner card.
2.4 Card installation and removal: Summarizes the pro-
cedure to install the scanner card assembly in the Model
6517 Electrometer, outlines scanner card output connections, and describes how to remove the card.
2.2 Handling precautions
To maintain high impedance isolation between channels,
care should be taken when handling the scanner card to avoid
contamination from such foreign materials as body oils.
Such contamination can substantially lower leakage resistances and increase offset currents, degrading card performance. To avoid possible contamination, always grasp the
scanner card by the side edges or covers. Do not touch board
surfaces, components, or input/output connector insulators.
Dirt build-up over a period of time is another possible source
of contamination. To avoid this problem, operate the electrometer and scanner card in a clean environment. If the card
becomes contaminated, it should be thoroughly cleaned as
explained in paragraph 4.2.
2.3 Connections
This paragraph provides the information necessary to connect your external test circuitry to the scanner card.
2.3.1 Model 6521 scanner card configuration
Model 6521 simplified schematic
Figure 2-1 shows a simplified schematic diagram of the
Model 6521. The scanner card has 10 input channels and a
single output. Note that each channel utilizes single-pole
switching with only the HI signal path switched. Input connections include H (HI), L (LO), while output connections
include H, L, and G (chassis ground).
Triax
Output
Out L
H
G
IN 2....9
H
L IN 1
BNC Inputs
H
L IN 10
2-1
Card Connections and Installation
F
M
F
M
igure 2-2
odel 6521 connecting cables
Triax output
cable
BNC Input
cables
Model 6521 connecting cables
Figure 2-2 shows the input/output connecting cables for the
Model 6521 card. Card connections include:
• INPUT 1-10 (channels 1-10): Each input is equipped
with a BNC coaxial cable, which is terminated with a
female BNC connector. The center conductor is HI,
while the outer shell is LO.
• OUTPUT: The triax output cable is equipped with a 3slot male triax connector. The center conductor is HI,
the inner ring is LO, and the outer shell is connected to
chassis ground.
2.3.2 Model 6522 scanner card configuration
Model 6522 simplified schematic
Figure 2-3 shows a simplified schematic diagram of the
Model 6522. As with the Model 6521, the Model 6522 scanner card has 10 input channels and a single output. Note that
each channel utilizes single-pole switching with only the HI
signal path switched. Input connections include H (HI), L
(LO), and G (chassis ground), while output connections include H, L, and G, which is connected to chassis ground.
Triax
Output
Out L
H
G
IN 2....9
H
L IN 1
G
Triax
Inputs
H
L IN 10
G
igure 2-3
odel 6522 simplified schematic
Model 6522 connecting cables
Figure 2-4 shows the input/output connecting cables for the
Model 6522 card. Card connections include:
• INPUT 1-10 (channels 1-10): Each input is equipped
with a triax cable terminated with a 3-lug female triax
connector. The center conductor is HI, the inner ring is
LO, and the outer shell is connected to chassis ground.
• OUTPUT: The output cable is terminated with a 3-slot
male triax connector. The center conductor is HI, the inner ring is LO, and the outer shell is connected to chassis ground.
2-2
F
igure 2-4
M
Figure 2-5
Typical amps function connections
F
odel 6522 connecting cables
Card Connections and Installation
Triax output
cable
Triax Input
cables
2.3.3 Input connections
All connections to the scanner card input jacks should be
made using appropriate low-noise coax (Model 6521) or triax (Model 6522) cables. See paragraph 1.9 in Section 1 for
cable recommendations.
WARNING
Make sure all power is off and any
stored energy in external circuitry is discharged before connecting or disconnecting cables.
2.3.4 Output connections
The supplied triax output cable should be connected to the
Model 6517 INPUT jack.
2.3.5 Typical connecting schemes
Figure 2-5 through Figure 2-8 show typical connecting
schemes for using the scanner card for amps, volts, ohms,
and coulombs measurements.
To
6517
Input
Jack
To
6517
Input
Jack
Out L
Out L
Coax
Input
Cables
H
G
H
G
IN 2....9
Model 6521
IN 2....9
H
L
H
L
Note: Model 6522 similar
exept that triax inputs
are used.
Triax
Input
Cables
H
L
G
H
L
G
1
Current
Sources (10)
10
1
V
Sources (10)
10
V
Voltage
The Model 6521 is intended for current
measurements. The Model 6522 is designed for all Model 6517 measurement
functions. The Model 6517 should be programmed for the voltage or current scan
mode as appropriate. (See paragraph
3.4.4.)
NOTE
Model 6522
igure 2-6
Typical volts function connections
2-3
Card Connections and Installation
F
F
Triax
Input
Cables
To
6517
Input
Jack
Note: Set Model 6517 for
internal voltage
source connection.
Caution: Set voltage source
limit to 200V.
H
Out L
G
IN 2....9
Model 6522
igure 2-7
Typical ohms function connections
Cables
To 6517
Input jack
H
Out L
G
IN 2....9
Coax
Input
H
L
G
H
L
G
1
Resistors (10)
10
To V-Source HI
on 6517
1
Sources (10)
10
Charge
2.3.6 Guarded operation
The Model 6522 supports guarded voltage measurements.
(The Model 6517 cannot be operated in the guarded mode
when the Model 6521 is installed.) When using guarding, the
inner shield routes the guard signal, while the outer shield remains at chassis ground. Thus, signal LO must be routed using a path external to the scanner card. Figure 2-9 shows
typical guarded connections.
In order to use guarding, the Model 6517 Electrometer must
be placed in the guarded mode. Refer to the Model 6517 User’s Manual for more details on guarded operation.
2.4 Card installation and removal
This paragraph explains how to install and remove the Model
6521/22 card assembly from the Model 6517 Electrometer.
WARNING
Installation or removal of the Model
6521/22 should be performed only by
qualified service personnel. Failure to
recognize and observe standard safety
precautions could result in personal injury or death.
Model 6521
igure 2-8
Typical coulombs function connections
CAUTION
To prevent contamination to the scanner card that could degrade performance, handle the card assembly only
by the card edges and covers.
2-4
F
To
6517
Out L
Input
Jack
Guard applied
to OUT L
Card Connections and Installation
Triax
Input
Cables
H
G
IN 2....9
H
L
Guard
G
H
L
G
Guard
1
V
Connect low-impedance
terminal of all10 sources
10
V
together
Note: Put Model 6517
Model 6522
in guard mode
igure 2-9
Typical guarded volts connections (Model 6522 only)
2.4.1 Scanner card installation
Perform the following steps, and refer to Figure 2-10 to install the card assembly in the Model 6517 Electrometer:
WARNING
Turn off power to all instrumentation
(including the Model 6517
Electrometer), and disconnect all line
cords. Make sure all power is removed
and any stored energy in external
circuitry is discharged.
1. Remove the cover plate from the OPTION SLOT on the
rear panel of the Model 6517 Electrometer. To do so, pry
out the two fasteners, then remove the cover plate.
To 6517 Rear Panel
common terminal
2. Slide the card edges into the guide rails inside the
electrometer.
3. Carefully push the card all the way forward until it seats
in the internal connector.
4. After the card is fully seated, tighten the mounting
screw.
WARNING
The mounting screw must be securely
fastened to ensure a proper ground connection to avoid possible shock hazards.
5. After installation, connect the output cable to the electrometer as discussed below.
2-5
Card Connections and Installation
F
Warning: Secure mounting screw
to assure proper grounding
igure 2-10
Scanner card installation
2-6
Card Connections and Installation
2.4.2 Output connections to electrometer
After installation, be sure to connect the scanner card triax
output cable to the Model 6517 INPUT jack. Figure 2-11
shows typical output connections.
2.4.3 Scanner card removal
Follow the steps below to remove the scanner card from the
multimeter:
WARNING
Turn off power to all instrumentation
(including the Model 6517 Electrometer), and disconnect all line cords. Make
Connect Output cable
to 6517 input jack
sure all power is removed and any
stored energy in external circuitry is discharged.
1. Loosen the mounting screw.
2. Carefully slide the card out of the electrometer.
3. If the electrometer is to be operated without the scanner
card installed, install the cover plate over the OPTION
SLOT.
NOTE
The Model 6517 should not be operated
without the OPTION SLOT cover in place
because internal temperature changes
could affect accuracy.
Figure 2-11
Output connections
2-7
Card Connections and Installation
2-8
3
Operation
3.1 Introduction
This section contains detailed information on front panel and
IEEE-488 bus operation of the Model 6521/22. The information in this section is organized as follows:
3.2 Signal limitations: Summarizes the maximum signals
that can be applied to the Model 6521/22.
3.3 Scanner card detection: Discusses how the scanner
card is detected and how to determine whether or not
the card is installed with a bus command.
3.4 Front panel operation: Gives an overview of the Mod-
el 6517 Electrometer front panel scanner controls and
discusses how to open and close channels and perform
basic scanning.
3.5 IEEE-488 bus operation: Summarizes bus commands
necessary to control the scanner card and gives an overview of general bus scanner operation.
3.6 Measurement considerations: Discusses a number of
measurement considerations that should be taken into
account when using the scanner card with the Model
6517.
3.7 Typical applications: Discusses typical applications
for the Model 6521/22.
NOTE
Before using the Model 6521/22 scanner
card, you should be thoroughly familiar
with the operation of the Model 6517
Electrometer. See the Model 6517 User’s
Manual for details.
3.2 Signal limitations
CAUTION
To prevent damage to the Model 6521/
22, do not exceed the maximum signal
level specifications of the card.
3.2.1 Model 6521 signal limitations
To prevent over-heating or damage to the relays, never exceed the following maximum signal levels when using the
Model 6521:
• Maximum signal level (HI to LO): 30V, 500mA, 10VA
(resistive load)
• Maximum common-mode voltage (LO to chassis
ground): <30V peak
WARNING
Applying >30V peak common-mode
voltage will result in a shock hazard.
3.2.2 Model 6522 signal limitations
To prevent over-heating or damage to the relays, never exceed the following maximum signal levels when using the
Model 6522:
• Maximum signal level (HI to LO): 200V, 500mA, 10VA
(resistive load)
• Maximum common-mode voltage (LO to chassis
ground): <250V peak
3-1
Operation
CAUTION
Use special caution when using the
Model 6517 voltage source with the
Model 6522. Although the voltage
source has a maximum output voltage
of 1000V, the maximum signal level that
can be switched by the Model 6522 is
200V. It is recommended that you program the Model 6517 voltage source
limit to 200V when using the Model
6522. (See paragraphs 3.4 and 3.5 for
details.)
3.2.3 Relay operation
Relays are normally opened and closed when the Model
6517 is programmed to do so, and when scanning is in
progress. Note, however, that all relays will open when Model 6517 power is turned off.
3.3 Scanner card detection
3.3.2 Scanner option bus query
*OPT? is an IEEE 488.2 common query which will allow
you determine whether or not the Model 6521/22 card is installed. The response to this query indicates whether or not
the scanner is present with an appropriate message. Refer to
the Model 6517 User’s manual for more details on using the
*OPT? query.
3.4 Front panel operation
The following paragraphs give an overview of the various
Model 6517 Electrometer menu items used with the scanner
and also discuss opening and closing channels and scanning
operation.
3.4.1 Scanning controls
The following controls are used for scanning:
CARD: This key accesses the scanning menu (discussed in
paragraph 3.4.2 below) to control most scanning operations.
3.3.1 Power-up detection
The scanner card is detected only at power-on. If the card is
plugged into the Model 6517 after the power is turned on, the
card will not be recognized as being present by the Model
6517.
CAUTION
Plugging in the scanner card with power
turned on may result in damage to both
the Model 6521/22 and the Model 6517
Electrometer. To avoid damage, never
install or remove the scanner card from
the electrometer with the power turned
on.
If the card is not present at power-on, scanner bus commands
or queries will generate a “Missing hardware” error, and attempted front panel operations pertaining to the scanner will
result in messages to inform you that no scanner is present.
CONFIG CARD: Pressing these two keys in succession
will display the card configuration menu. This menu lets you
select current or voltage scanning, settling time, and voltage
source limit.
EXIT: Pressing this key during a scan sequence will abort
the scan and return the instrument to normal operation.
Function Keys: As with normal operation, the function keys
control the measurement function to be used during
scanning.
3.4.2 Scan control and configuration menus
To access the scan control menu, simply press the
Model 6517 OPTION CARD key. You can then access the
various levels of the scan control menu, which is outlined in
Table 3-1.
To access the card configuration menu, press CONFIG then
CARD. The card configuration menu is summarized in
Table 3-2.
3-2
Table 3-1
Scan control menu
Menu item* Description
Operation
CHANNEL CLOSURES
CLOSE-CHANNEL
OPEN-ALL-CHANNELS
PERFORM-SCAN
EXTERNAL
INTERNAL
* Access scan control menu with OPTION CARD key.
Table 3-2
Card configuration menu
Menu item* Description
CONFIGURE SCANNER
INTERNAL
CHANNELS
SCAN-MODE
VSRC-LIMIT
SETTLING-TIME
EXTERNAL
* Access card configuration menu by pressing CONFIG then CARD.
Close channel manually.
Close selected channel.
Open all closed channels.
Perform internal or external scanning.
Scan with external scanner.
Scan with 6521/22.
Set up scanning operation.
Configure internal scanner.
Select channels in scan list.
Select voltage or current mode.
Select voltage source limit.
Set settling time.
Configure external scan.
3.4.3 Closing and opening channels
Closing channels
1. Press the CARD button. The instrument will display the
following:
SCANNER OPTION
CHANNEL-CLOSURES PERFORM-SCAN
2. Select CHANNEL-CLOSURES, then press ENTER.
The following will be displayed:
CHANNEL SELECTION
CLOSE-CHANNEL OPEN-ALL-CHANNELS
3. Choose CLOSE-CHANNEL, then press ENTER, and
note the unit prompts you for the channel to close:
ENTER CHAN#01 (1-10)
4. Using the range keys, choose the channel to close, then
press the ENTER key.
5. The selected channel will close, and the instrument will
return to normal measurement display.
Opening channels
1. Press the CARD button. The instrument will display the
following:
SCANNER OPTION
CHANNEL-CLOSURES PERFORM-SCAN
2. Select CHANNEL-CLOSURES, then press ENTER.
The following will be displayed:
CHANNEL SELECTION
CLOSE-CHANNEL OPEN-ALL-CHANNELS
3. Choose OPEN-ALL-CHANNELS, then press ENTER.
4. The closed channel will open, and the instrument will
return to normal measurement display.
NOTE
Any closed relays will open if the Model
6517 power is turned off.
3-3
Operation
3.4.4 Card configuration
Selecting scan list channels
To choose the channels to include in the scan list, perform
the following steps:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the instrument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select CHANNELS, then press ENTER, and note that
the instrument displays the following:
CONFIGURE CHANNELS
INTERNAL-CHANS EXTERNAL-INPUTS
4. Select INTERNAL-CHANS, then press ENTER. The
following will then be displayed:
SET INTERNAL CHANS
1=ON 2=ON 3=ON 4=ON 5=ON
6=ON 7=ON 8=ON 9=ON 10=ON
5. Using the range and cursor keys, select the channels you
wish to include in the scan list. (ON = include channel;
OFF = exclude channel.)
6. Press the ENTER key to complete programming, then
press EXIT twice to return to normal display.
Scan mode
3. Select SCAN-MODE, then press ENTER. The instrument will display the following:
SCAN MODE
VOLTAGE CURRENT
4. Select VOLTAGE or CURRENT as desired, then press
ENTER.
5. Press EXIT twice to return to normal display.
Setting the voltage source limit
The maximum recommended voltage for the Model 6522
card is 200V, while the Model 6521 is limited to 30V for
safety reasons. Use the following procedure to program the
voltage limit up to a maximum of 200V.
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the instrument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select VSRC-LIMIT, then press ENTER. The instrument will display the following:
LIMIT VSRC TO 200V
YES NO
4. To limit the voltage source to 200V, select YES, then
press ENTER.
5. Press EXIT twice to return to normal display.
The scanner card can be configured for either voltage or current operation. When in the voltage mode, the card is configured for break-before-make operation. (The relay for the
presently closed channel opens before the next channel relay
closes.) When in the current mode, the HI and LO terminals
of each input channel remain shorted together when the
channels are open.
Program the scan mode as follows:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the instrument displays the following message:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3-4
Settling time
The setting time parameter allows you to program a delay
time to allow circuit settling. The settling time between channels can be set to any value in the range of 0sec to
999.999sec. Program the settling time as follows:
1. Press CONFIG then CARD, and note that the following
is displayed:
CONFIGURE SCANNER
INTERNAL EXTERNAL
2. Select INTERNAL, press ENTER, and note that the instrument displays the following:
INTERNAL SCANNER
CHANNELS SCAN-MODE VSRC-LIMIT
SETTLING-TIME
3. Select SETTLING-TIME, then press ENTER, and note
that the instrument displays the following:
SETTLE-t: 000.000sec
Operation
4. Set the settling time as desired, then press ENTER.
5. Press EXIT to return to normal display.
3.4.5 Scanning procedure
NOTE
Before scanning, you should configure the
card as covered in paragraph 3.4.4.
1. Press the CARD key, and note that the instrument displays the following:
SCANNER OPTION
CHANNEL-CLOSURES PERFORM-SCAN
2. Select PERFORM-SCAN, then press ENTER. The
Model 6517 will prompt you as to the type of scan:
CHOOSE SCAN TYPE
EXTERNAL INTERNAL
3. Select INTERNAL, then press ENTER. You will then be
prompted to set the scan count (number of scans):
SCAN COUNT = 00010
4. Set the scan count to the desired value, then press the
ENTER key. The instrument will then prompt you as to
whether or not you wish to use the scan timer:
USE SCAN TIMER?
YES NO
5. If you wish to use the timer to control the length of the
scan, select YES; otherwise choose NO, then press
ENTER.
6. If you are using the scan timer, the unit will prompt you
for the scan interval (length of scan):
INTRVL = 00002.500
7. Set the scan interval to the desired value, then press ENTER. The instrument will then display the following
asking whether or not you intend to store measurement
data in memory:
DATA TO MEMORY?
YES NO
8. If you desire to store measurement data in the Model
6517 buffer, select YES; otherwise choose no, then press
ENTER.
9. Assuming that you chose to store readings in the buffer,
the instrument will display the following:
00100 RDGS TO BUFFER
Press ENTER to continue
10. Press ENTER to continue, and the unit will display one
last prompt before starting the scan:
Press ENTER to begin
11. Press the ENTER key to start scanning. During scanning, the unit will display the current reading being processed. For example:
Storing reading 010 of 100
NOTE
To abort scanning at any time, press the
EXIT key. The unit will then display the
following message to indicate that scanning has been aborted:
SCANNING DISABLED
12. After the scan process has completed normally, the instrument will display the following:
SCAN COMPLETE
RECALL-DATA SCAN-AGAIN EXIT
13. Choose the desired option as follows:
RECALL-DATA: Choose this option if you wish to recall data stored in the buffer. Use the range keys to scroll
through readings.
SCAN-AGAIN: Select this option to scan again.
EXIT: Choose this option to exit scanning and return to
normal operation.
3.5 IEEE-488 bus operation
The following paragraphs summarize bus scanner commands and also cover such aspects as closing and opening
channels, card configuration, and scanning over the bus.
3.5.1 IEEE-488 bus scanner commands
Table 3-3 summarizes commands that control basic scanning
operations over the IEEE-488 bus. For information on other
bus commands, refer to the Model 6517 Electrometer User’s
Manual.
3-5
Operation
Table 3-3
Summary of IEEE-488 bus scanner commands
Command Description
:ROUTe
:CLOSe <channel list>
:STATe?
:CLOSe? <channel list>
:OPEN <channel list>
:OPEN:ALL
:OPEN? <channel list>
:SCAN
[:INTernal] <scan list>
[:INTernal]?
:EXTernal <n channels>
:EXTernal?
:LSELect INTERNAL | EXTernal | NONE
:LSELect?
:STIMe <n>
:STIMe?
:SMEThod VOLTage | CURRent
:SMEThod?
:VSLimit <b>
:VSLimit?
NOTES:
1. When querying specific channel states, 1 = closed, 0 = open.
2. Internal scan list = 2 to 10 channels.
3. Internal channel list = 1 to 10.
4. Selecting internal scan (LSEL INT) requires that a Model 6521 or 6522 be installed.
5. Sending the STIMe, SMEThod, or VSLimit commands without a 6521/22 installed will generate a “Hardware Missing” error.
Route subsystem.
Close channels.
Query channel state.
Query closed channels.
Open channels.
Open all channels.
Query open channels.
Scanning commands.
Program internal scan list.
Query internal scan list.
Program external scan number of channels (1 <=n <=400).
Query external scan number of channels.
Select scan list.
Query selected scan list.
Program settling time (0.000 <= n <= 999.999 sec).
Query settling time.
Select scan method (voltage=break before make).
Query scan method.
Set voltage source limit (1 = 200V)
Query voltage source limit.
3.5.2 Closing and opening channels
Closing channels
Use the CLOSe command to close any of the ten channels on
the scanner card. For example, to close channel 3, you would
send the following command over the bus:
:ROUTe:CLOSe (@3)
Similarly, the following command would be used to close
channel 7:
:ROUTe:CLOSe (@7)
Note that closing a specific channel will automatically open
any other closed channel.
3-6
Opening channels
Send the OPEN command to open any close channels. For
example, to open channel 3, send the following command.
:ROUTe:OPEN (@3)
Alternatively, you can send the following command to open
any closed channel:
:ROUTe:OPEN:ALL
NOTE
Turning off Model 6517 power will also
open any closed channel.
Operation
3.5.3 Card configuration
Settling time
Use the STIMe command to program the channel settling
time, which can be programmed in the range of 0sec to
999.999sec. For example, to program a 50msec settling time,
send the following command:
:ROUTe:SCAN:STIMe 50E-3
Scan method
The scanner card can be configured for either voltage or current operation. When in the voltage mode, the card is configured for break-before-make operation. When in the current
mode, the HI and LO terminals of each input channel remain
shorted together when the channels are open.
Scan method is programmed with the SMEThod command.
For example, to configure the card for current operation,
send the following command:
:ROUT:SCAN:SMET CURR
Similarly, send the following command to configure the card
for voltage operation:
:ROUT:SCAN:SMET VOLT
Setting the voltage source limit
The maximum recommended voltage for the Model 6522
card is 200V, while the Model 6521 is limited to 30V for
safety reasons. Use the VSLimit command to program the
voltage limit to 200V. For example, the following command
sets the voltage limit to 200V:
:ROUTe:SCAN:VSLimit 1
tling time of 100msec, current operation, and a voltage
source limit of 200V:
:ROUT:SCAN:STIM 0.1
:ROUT:SCAN:SMET CURR
:ROUT:SCAN:VSL 1
Step 3: Enable scan
After programming the scan list and functions, use the
:ROUT:SCAN:LSET INT command to enable scanning as
follows:
:ROUT:SCAN:LSET INT
The scanning sequence will then begin using the scan list and
other scan parameters previously programmed.
To disable a scan sequence in progress, send the following
command:
:ROUT:SCAN:LSET NONE
3.6 Measurement considerations
Many measurements made with the aid of the Model 6521/
22 Scanner Cards are subject to various effects that can seriously affect low-level measurement accuracy. The following
paragraphs discuss some of these effects and ways to minimize them.
For further information on making accurate low-level measurements, refer to the Low Level Measurements handbook
available from Keithley Instruments. Contact the Keithley
Instruments Applications Department for more information.
3.5.4 Bus scanning
Follow the steps below to perform scanning over the bus.
Step 1: Program internal scan list
Use the :ROUT:SCAN:INT command to program a scan list
(channels you wish to scan). For example, assume that you
wish to scan channels 1, 3, and 5. This scan list would be programmed by sending the following command:
:ROUT:SCAN:INT (@ 1,3,5)
Step 2: Configure scanner card
Configure the scanner card as outlined previously. For example, the following commands will program the card for a set-
3.6.1 Generated currents
Any extraneous generated currents in a test system will add
to the desired measured current, degrading sensitive current
measurements. The following paragraphs discuss the more
commonly encountered generated currents and methods to
minimize their effects when using the Model 6521/22 Scanner Card.
Offset currents
Offset currents can be generated from a variety of internal or
external sources. Internal offsets can be generated within the
meter or scanner card itself, while external offsets can be
present in connecting cables, connectors, or test fixtures.
3-7
Operation
F
P
Regardless of the source of the offsets, they can be nulled using the electrometer REL feature. See the Model 6517 User’s
Manual for more information on using relative.
Triboelectric effects
Triboelectric currents are generated by charges created between a conductor and insulator by friction. In this situation,
free electrons rub off the conductor and create a charge imbalance that causes the current to flow. A typical example
would be the electrical currents generated in a coax or triax
cable by flexing that cable or otherwise subjecting it to stress.
Low-noise cables are constructed with a special graphite
coating under the shield(s) to minimize friction and provide
a conducting path to minimize charge generation. Keithley
triax cables and special low-noise coax cables are constructed in this manner; such cables should be used for any lowlevel measurements made using the Model 6521/22 Scanner
Card. Note the conventional cable such as RG-58 is not recommended for use with the Model 6521 because of high
noise currents.
Even low-noise cables generate some currents when subjected to stress. For that reason, the following precautions should
be taken to minimize unwanted currents that might be generated by cables:
• Keep all cables as short as possible.
• Keep cable temperature variations to a minimum.
• Tie down or tape all connection cables to a rigid pole or
fixture.
• Do not bend or flex cables during sensitive
measurements.
• Keep vibration sources such as motors and pumps well
away from connecting cables.
3.6.2 Path isolation
The path isolation is simply the equivalent impedance between any two test paths in a measurement system. Ideally,
the path isolation should be infinite, but the actual resistance
and distributed capacitance of cables and connectors results
in less than infinite path isolation values for these devices.
The capacitive component of path isolation impedance is
generally fixed by design, but the resistive component can be
reduced by environmental and other factors, as we will now
discuss.
Path isolation resistance forms a signal path that is in parallel
with the equivalent resistance of the DUT, as shown in Figure 3-1. For low-to-medium device resistance values, path
isolation resistance is seldom a consideration; however, it
can seriously degrade measurement accuracy when testing
high-impedance devices. The voltage measured across such
a device, for example, can be substantially attenuated by the
voltage divider action of the device source resistance and
path isolation resistance, as shown in Figure 3-2.
Another phenomenon negatively affected by lower path resistance values are leakage currents that can be generated
through these resistances by voltage sources in the system.
Such leakage currents can, of course, seriously affect lowlevel current measurement accuracy. Thus, it is imperative
that the path isolation resistance be as high as possible in order to minimize these effects.
R
DUT
R
PATH
E
DUT
R
IN
V
Dielectric absorption
Dielectric absorption in a triax or coax connector insulator
can occur when a voltage applied to the insulator causes pos-
DUT
Scanner
Card
Model 6517
itive and negative charges within that insulator to separate.
When the voltage is removed, the separated charges generate
a decaying current through circuitry connected to the scanner
card.
To minimize the effects of dielectric absorption, avoid apply-
= Source Resistance of DUT
R
DUT
E
= Source EMF of DUT
DUT
= Path Isolation Resistance
R
PATH
= Input Resistance of Model 6517
R
IN
ing more than a few volts to the input or output connectors of
a scanner card to be used for sensitive current measurements.
In cases where this practice is unavoidable, it may take min-
igure 3-1
ath isolation resistance
utes or even hours in some cases for currents caused by dielectric absorption to dissipate.
3-8
Operation
F
F
P
R
DUT
E
E
DUT
=
E
OUT
R
E
DUT
+
R
DUTRPATH
R
PATH
PATH
OUT
igure 3-2
Voltage attenuation by path isolation resistance
3.6.3 Noise
Noise induced into a switching system can have serious detrimental effects on measurements made with the system.
Chief among noise considerations are magnetic fields, radio
frequency interference, and ground loops.
Magnetic fields
When a conductor cuts through magnetic lines of force, a
very small current is generated. This phenomenon will frequently cause unwanted signals to occur in the test leads of a
scanning system. If the conductor has sufficient length, even
weak magnetic fields like those of the earth can create sufficient signals to affect low-level measurements. Two ways to
reduce these effects are: (1) reduce the lengths of the test
leads, and (2) minimize the exposed circuit area. In extreme
cases, magnetic shielding may be required. Special metal
with high permeability at low flux densities (such as mu metal) is effective at reducing these effects.
Even when the conductor is stationary, magnetically-induced signals may still be a problem. Fields can be produced
by various signals such as the AC power line voltage. Large
inductors such as power transformers can generate substantial magnetic fields, so care must be taken to keep the switching and measuring circuits a good distance away from these
potential noise sources. At high current levels, even a single
conductor can generate significant fields. These effects can
be minimized by using twisted pairs, which will cancel out
most of the resulting fields.
Electromagnetic interference (EMI)
The electromagnetic interference characteristics of the Model 6517 Electrometer/High Resistance System comply with
the electromagnetic compatibility (EMC) requirements of
the European Union (EU) directives as denoted by the CE
mark. However, it is still possible for sensitive measurements
to be affected by external sources. In these instances, special
precautions may be required in the test setup.
Sources of EMI include:
• Radio and TV broadcast transmitters.
• Communications transmitters, including cellular
phones and handheld radios.
• Devices incorporating microprocessors and high-speed
digital circuits.
• Impulse sources as in the case of arcing in high-voltage
environments.
The instrument, measurement leads, and other cables should
be kept as far away as possible from any EMI sources.
Shielding measurement leads and the multimeter may reduce
EMI to acceptable levels. In extreme cases, a specially constructed screen room may be required to sufficiently attenuate troublesome signals.
Many instruments incorporate internal filtering that may
help reduce EMI effects. In some cases, additional external
filtering may be required. Keep in mind, however, that filtering may have detrimental effects on the measurement.
Ground loops
When two or more instruments are connected together, care
must be taken to avoid unwanted signals caused by ground
loops. Ground loops usually occur when sensitive
instrumentation is connected to other instrumentation with
more than one signal return path such as power line ground.
As shown in Figure 3-3, the resulting ground loop causes
current to flow through the instrument LO signal leads and
then back through power line ground. This circulating
current develops a small but undesirable voltage between the
LO terminals of the two instruments. This voltage will be
added to the source voltage, affecting the accuracy of the
measurement.
Signal Leads
Instrument 1 Instrument 2 Instrument 3
Ground Loop
Current
Power Line Ground
igure 3-3
ower line ground loops
Figure 3-4 shows how to connect several instruments together to eliminate this type of ground loop problem. Here, only
one instrument is connected to power line ground. Ground
loops are not normally a problem with instruments having
3-9
Operation
F
E
F
isolated LO terminals. However, all instruments in the test
setup may not be designed in this manner. When in doubt,
consult the manual for all instrumentation in the test setup.
Instrument 1 Instrument 2 Instrument 3
Power Line Ground
igure 3-4
liminating ground loops
3.6.4 Keeping connectors clean
As is the case with any high-resistance device, the integrity
of the triax and BNC connectors used on the Model 6521/22
can be compromised if they are not handled properly. If connector insulators become contaminated, the insulation resistance will be substantially reduced, affecting highimpedance measurement paths. Oils and salts from the skin
can contaminate connector insulators, reducing their resistance. Also, contaminants present in the air can be deposited
on the insulator surface. To avoid these problems, never
touch BNC or triax connector insulating materials. In addition, the scanner card should be used only in clean, dry environments to avoid contamination.
If the connector insulators should become contaminated, either by inadvertent touching, or from air-borne deposits, they
can be cleaned with a cotton swab dipped in clean methanol.
After thorough cleaning, they should be allowed to dry for
several hours in a low-humidity environment before use, or
they can be dried more quickly using dry nitrogen.
rent is supplied by the high-impedance source being measured, and no loading occurs. Leakage between the guard
shield and the outer (chassis ground shield) may be considerable, but that leakage current is of no consequence since it
is supplied by the low-impedance preamp rather than by the
high-impedance source itself.
6517
Preamp output
+
HI
-
Voltage
Source
RS = Source resistance
RL = Leakage resistance
RG = Guard-to-ground resistance
R
L
R
S
V
S
R
G
HI
LO LO
igure 3-5
Guarded operation
In order to use guarding with the Model 6522 Scanner Card,
be sure to make appropriate signal connections, and place the
Model 6517 in the guarded mode (see the Model 6517 User’s
Manual for details).
NOTE
The Model 6521 Scanner Card is designed
for current measurements and cannot be
used for guarded voltage measurements.
The Model 6517 Electrometer cannot be
placed in the guarded mode when the
Model 6521 is installed.
See Section 4 for additional information on cleaning scanner
card connectors.
3.6.6 Voltage/current scan mode
The Model 6517 Electrometer can be programmed for the
voltage or current scan mode. When in the voltage scan
mode, the relays are operated under a break-before-make ba-
3.6.5 Guarded operation
Guarding is useful when making measurements from voltage
sources that have high internal source resistances. As shown
in Figure 3-5, guarding consists of surrounding a signal-carrying lead with a guard signal that is driven by the low-impedance electrometer preamp output. Since the guard shield
is at the same potential as the HI signal lead, no leakage cur-
sis, which means that the relay for the present channel opens
before the relay for the next channel closes. Thus, to avoid
possible damage to the Model 6521/6522 or external circuits, you should always program the Model 6517 for the
voltage scan mode when switching voltages. The voltage
scan mode is also recommended for resistance or charge
function switching.
3-10
Operation
Figure 3-6
Capacitor leakage test system
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
When the Model 6517 is programmed for the current scan
mode, a ground relay contact shorts the HI and LO terminals
of each off channel, maintaining a true current path at all
times. For that reason, you should program the Model 6517
to operate in the current scan mode when switching currents.
See paragraphs 3.4.4 and 3.5.3 for more information on selecting the voltage or current scan modes.
3.7 Typical applications
Typical applications for the Model 6521/22 are discussed in
the following paragraphs. For more information on these and
other scanner card applications, contact the Keithley Applications Department.
3.7.1 Capacitor leakage measurements
One of the more important test parameters associated with
capacitors is their leakage characteristics. Such leakage may
be specified as the “IR” (Insulation Resistance), or it may be
expressed as leakage current at a given voltage, usually the
operating voltage.
value in making such tests. Instead a fixed voltage is applied
to the capacitor, and the resulting leakage current is
measured. Leakage resistance can then be determined by
simple computation.
In many cases, a number of capacitors of a given type are
tested in order to obtain useful statistical data. In those cases,
an automated test system like the one shown in Figure 3-6
may be used to test a number of capacitors. The system includes a Model 6517 Electrometer to apply test voltages and
measure leakage currents, while the Model 6521/22 Scanner
card provides the necessary switching functions. The electrometer ohms function can be used, of course, to measure
the leakage resistance directly. Resistors are connected in series with the capacitors under test to limit current and reduce
noise.
The test configuration shown in Figure 3-6 can be used only
where test speed is unimportant because of the capacitor
charging time caused by large RC time constants, particularly with larger value capacitors. If shorter test times are required, external switching can be added to allow a voltage to
be applied to each capacitor for a “bias” time before each
test. (The bias time is the period required for the capacitor to
charge fully, or about five RC time constants.)
Since capacitor leakage characteristics are largely dependent
on the applied voltage, an ordinary ohmmeter is of little
TRIG LINK
115V
LINE RATING
50-60HZ
50VA MAX
AC ONLY
Voltage source HI
LINE FUSE
SLOWBLOW
1/2A 90-125V
1/4A 180-250V
IEEE-488
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
Triax Cable
!
INPUT
250V PEAK
Model 6517 Electrometer
DIGITAL
I/O
6521/22 Card
HI
1
10
Note: Electrometer must be configured
for internal voltage source connection
Capacitors under test
C
1R1
C10R
10
3-11
Operation
F
H
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
3.7.2 High-resistance measurements
Resistors with values of 1GΩ or more are often referred to as
high-megohm resistors. Such resistors often exhibit unusual
characteristics such as changes in resistance with applied
voltage. (Such change in resistance is known as the voltage
coefficient, which is given in percent/volt, or ppm/volt.)
As with many other component evaluation tests, high-megohm resistance tests are often best performed on an automated basis since testing usually involves multiple devices. Figure 3-7 demonstrates a test system using the Model 6517
Electrometer along with a Model 6521/22 Scanner Card to
perform automated high-resistance testing on up to 10 resistors simultaneously. The test voltage is, of course, supplied
by the Model 6517 voltage source, while the electrometer
section measures the current through each resistor. The instrument then computes and displays the value of each resistor automatically.
Since the resistance of such devices varies with applied voltage, all testing should be done at the same voltage for comparative analysis to be valid. Alternatively, the voltage
coefficient may be determined by measuring the resistance at
two different voltages and then computing the voltage coefficient as follows:
R2R1–
Voltage Coefficient (%)
-----------------------------
R
1V2V1
100×=
–()
Where: V1 = first applied voltage
V2 = second applied voltage
R1 = resistance with V1 applied
R2 = resistance with V2 applied
Since high resistance values are involved, it is imperative
that only the highest-quality components be used for the test
fixture. All insulators throughout should be made of a material with very high resistance such as Teflon. Any residual
leakage current can be nulled out by suppressing the measured current.
3.7.3 Low-current measurements
Both the Models 6521 and 6522 are ideal for low-current
measurements because of their low offset currents. Also,
when the Model 6517 is programmed for the current scan
mode, the HI and LO terminals of all off channels are shorted
together, an important requirement when switching current
sources. (See paragraph 3.4.4 for information on programming the Model 6517 for the current scan mode.)
Figure 3-8 demonstrates an application using low-current
switching, with the current sources connected to the channel
inputs as usual. In this example, channel 1 is closed so that
current from the source flows into the electrometer INPUT
jack. All other channels are open, but their ground relays remain closed so that the current paths are not broken.
!
INPUT
250V PEAK
Model 6517 Electrometer
igure 3-7
igh-resistance test system
Triax Cable
DIGITAL
Voltage source HI
6521/22 Card
HI
Resistors under test
R
1
1
LINE FUSE
LINE RATING
115V
50-60HZ
SLOWBLOW
50VA MAX
1/2A 90-125V
AC ONLY
1/4A 180-250V
IEEE-488
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
TRIG LINK
I/O
10
Note: Electrometer must be configured
for internal voltage source connection
R
10
3-12
Operation
F
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
!
INPUT
250V PEAK
Model 6517 Electrometer
igure 3-8
Low-current test system
Triax Cable
DIGITAL
TRIG LINK
I/O
115V
LINE RATING
50-60HZ
50VA MAX
AC ONLY
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
IEEE-488
LINE FUSE
SLOWBLOW
1/2A 90-125V
1/4A 180-250V
HI
6521/22 Card
1
10
Closed channel
I
Open channel
I
Current Sources
under test
1
10
3-13
Operation
3-14
4
Service Information
WARNING
The information in this section is intended only for qualified service personnel. Some of the procedures may expose
you to hazardous voltages that could result in personal injury or death. Do not
attempt to perform these procedures
unless you are qualified to do so.
4.1 Introduction
This section contains information necessary to service the
Model 6521/22 scanner card and is arranged as follows:
4.2 Handling and cleaning precautions: Discusses han-
dling precautions and methods to clean the card should
it become contaminated.
4.3 Performance verification: Covers the procedures nec-
essary to determine if the scanner card meets stated
specifications.
4.4 Special handling of static-sensitive devices: Reviews
precautions necessary when handling static-sensitive
devices.
4.5 Principles of operation: Briefly discusses circuit
operation.
4.6 Troubleshooting: Presents some troubleshooting tips
for the Model 6521/22 including relay replacement precautions.
4.2 Handling and cleaning precautions
Because of the high-impedance areas on the Model 6521/22,
care should be taken when handling or servicing the card to
prevent possible contamination. The following precautions
should be observed when servicing the card.
4.2.1 Handling precautions
• Handle the card only by the edges and shields.
• Do not touch connector insulators.
• Do not touch any board surfaces or components not associated with the repair.
• Do not touch areas adjacent to electrical contacts.
• When servicing the card, wear clean cotton gloves.
• Do not store or operate the card in an environment
where dust could settle on the circuit board.
• Use dry nitrogen gas to clean dust off the board if
necessary.
4.2.2 Soldering considerations
Should it become necessary to use solder on the circuit
board, observe the following precautions:
• Use an OA-based (organic activated) flux, and take care
not to spread the flux to other areas of the circuit board.
• Remove the flux from the work areas when the repair
has been completed. Use pure water along with clean
cotton swabs or a clean soft brush to remove the flux.
4-1
Service Information
• Once the flux has been removed, swab only the repaired
area with methanol, then blow dry the board with dry
nitrogen gas.
• After cleaning, the card should be allowed to dry in a
50°C low-humidity environment for several hours before use.
4.3 Performance verification
The following paragraphs discuss performance verification
procedures for the Model 6521/22, including offset current,
channel and input isolation, contact resistance, and contact
potential.
CAUTION
Contamination will degrade the performance of the card. To avoid contamination, always grasp the card by the side
edges. Do not touch connector insulators, board surfaces, or components.
NOTE
Failure of any performance verification
test may indicate that the scanner card or
its input/output connectors are contaminated. See paragraph 4.2 for information
on cleaning the card.
4.3.1 Environmental conditions
All performance verification measurements should be made
under the following environmental conditions:
• Offset current and isolation measurements: 23°C,
<60% relative humidity.
• All other measurements: 18°C to 28°C, <70% relative
humidity.
4.3.2 Recommended verification equipment
Table 4-1 summarizes the equipment necessary for performance verification, along with an application for each item.
NOTE
Various coax/triax cables, adapters, and
wires (not shown) are also required. Use
only high-quality low-noise coax/triax
cables and adapters, and Teflon-insulated
wires where required. (See paragraph 1.9
in Section 1 for cable recommendations.)
Make sure that connector and adapter
insulators are clean and free of
contamination.
4.3.3 Scanner card connections
Various cables should be connected to the input/output jacks
before the card is installed in the electrometer. Also, a number of triax/BNC adapters are required. See the pertinent
drawings for each procedure and the detailed connection information provided in Section 2.
4-2
Table 4-1
Recommended verification equipment
Manufacturer/
Description
Electrometer
Digital Multimeter
Model Specifications
Keithley 6517
20pA, 1%
20GΩ, 20TΩ, 1%
Keithley 2001
20Ω, 79ppm
1
Application
Control card, measure offset current, isolation
Contact resistance
200mV, 44ppm
1
Full-range input specifications.
2
Various coax/triax cables, adapters, and wires (not shown) are also required. Use only high-quality low-noise coax/triax
cables and adapters, and Teflon insulated wires where required. make sure that connector and adapter insulators are clean
and free of contamination.
Service Information
Figure 4-1
Connections for offset current verification
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
4.3.4 Offset current tests
Offset current tests are performed by measuring the residual
current of each Model 6521/22 channel by closing each
channel in succession and then measuring the offset current
using the Model 6517 Electrometer.
Proceed as follows:
1. With the power off, install the Model 6521/22 Scanner
Card in the Model 6517 OPTION SLOT.
2. Connect the scanner card triax output cable to the Model
6517 INPUT jack. (See Figure 4-1.) Also install the
BNC (Model 6521) or triax (Model 6522) shielding cap
on each channel 1 input cable connector.
3. Program the Model 6517 for the current scan mode (see
paragraph 3.4.4).
Triax Cable
!
INPUT
250V PEAK
Model 6517 Electrometer
DIGITAL
TRIG LINK
I/O
115V
LINE RATING
50-60HZ
50VA MAX
AC ONLY
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
LINE FUSE
SLOWBLOW
1/2A 90-125V
1/4A 180-250V
IEEE-488
4. Turn on the electrometer, and allow a one-hour warm-up
period before performing the offset current tests.
5. Select the electrometer amps function and the 20pA
range. Leave zero check enabled for the time being.
6. Press the OPTION CARD button, then use the
CHANNEL-CLOSURES menu to close channel 1 on
the scanner card.
7. Disable zero check, and allow the reading to settle.
8. Verify that the Model 6517 current reading, which represents the scanner card offset current, is <1pA.
9. Enable zero check, then open channel 1.
10. Repeat steps 6 through 9 for channels 2 through 10. For
each channel, be sure to connect the shielding cap to the
input cable, close the appropriate channel, then verify
that the offset current is <1pA.
HI
LO
Ground
OUT
H
IN 2....9
L
G
H
L IN 1
H
L IN 10
Install
Shielding
Caps on
Inputs
Note: Model 6522 connection
is the same except for
triax input.
Model 6521
4-3
Service Information
F
C
4.3.5 Signal path contact resistance tests
Perform the following steps to verify that the signal path contact resistance of each channel is within specified limits.
1. Connect an alligator clip lead to the HI and LO input
jacks of the DMM to be used for the test. (See Figure
4-2.)
2. Turn on the DMM, and allow it to warm up for one hour
before making the tests.
3. Select the ohms function and the 20Ω range on the
DMM.
4. Temporarily short the ends of the DMM leads together,
then enable the DMM REL mode to null out any residual test lead resistance. Leave REL enabled for the remainder of the contact resistance tests.
5. With the power off, install the scanner card in the Model
6517 Electrometer OPTION SLOT.
Input HI
SENSE
INPUT
2001 MULTIMETER
RANGE
RANGE
Ω 4 WIRE
HI
350V
1100V
!
PEAK
PEAK
LO
500V
PEAK
INPUTS
F
R
AUTO
FRONT/REAR
2A 250V
AMPS
CAL
Input LO
EDIT ERR REM TALK LSTN SRQ REAR REL FILT MATH 4W AUTO ARM TRIG SMPL
1234567891012345678910
PREV
DCV ACV DCI ACI Ω2 Ω4
DISPLAY
POWER
NEXT
REL TRIG
INFO LOCAL
STORE RECALL
CHAN SCAN
FILTER MATH
CONFIG MENU
Model 2001 DMM
FREQ TEMP
EXIT ENTER
6. Connect the DMM LO input lead to the HI terminal of
the channel 1 input cable using bare wire or a suitable
adapter, and connect the DMM HI input lead to the HI
terminal of the scanner card output jack with a similar
adapter. (Again, refer to Figure 4-2.)
7. Turn on the Model 6517 power.
8. Press the OPTION CARD button, then use the
CHANNEL-CLOSURES menu to close channel 1 on
the scanner card.
9. Note the resistance reading on the DMM. Verify that the
reading is <1Ω.
10. Repeat steps 8 and 9 for channels 2-10. When testing
each channel, be sure to:
• Connect the DMM to the HI input terminal of the
channel being tested.
• Close the channel being tested.
Out
H
IN 2....9
L
G
H
L
H
L
IN 1
IN 10
igure 4-2
onnections for signal path contact resistance tests
Model 6521/22 Card
Note: Model 6521 shown. Model
6522 connections same except
for triax inputs.
Channel 1 connection shown
4-4
Service Information
Figure 4-3
Connections for ground relay contact resistance tests
4.3.6 Ground relay contact resistance tests
Perform the following steps to verify that the contact resistance of the ground relay for each channel is within specified
limits.
1. Connect an alligator clip lead to the HI and LO input
jacks of the DMM to be used for the test. (See Figure
4-3.)
2. Turn on the DMM, and allow it to warm up for one hour
before making the tests.
3. Select the ohms function and the 20Ω range on the
DMM.
4. Temporarily short the ends of the DMM leads together,
then enable the DMM REL mode to null out any residual test lead resistance. Leave REL enabled for the remainder of the contact resistance tests.
Input HI
SENSE
INPUT
2001 MULTIMETER
RANGE
RANGE
Ω 4 WIRE
HI
350V
1100V
!
PEAK
PEAK
LO
500V
PEAK
INPUTS
F
R
AUTO
FRONT/REAR
2A 250V
AMPS
CAL
Input LO
EDIT ERR REM TALK LSTN SRQ REAR REL FILT MATH 4W AUTO ARM TRIG SMPL
1234567891012345678910
PREV
DCV ACV DCI ACI Ω2 Ω4
DISPLAY
POWER
NEXT
REL TRIG
INFO LOCAL
STORE RECALL
CHAN SCAN
FILTER MATH
CONFIG MENU
Model 2001 DMM
FREQ TEMP
EXIT ENTER
5. With the power off, install the scanner card in the Model
6517 Electrometer OPTION SLOT.
6. Turn on the Model 6517 power.
7. Press CONFIG then CARD, and program the Model
6517 for the current scan mode. (See paragraph 3.4.4 for
details.)
8. Press the OPTION CARD button, then select OPENALL-CHANNELS in the CHANNEL SELECTION
menu to make certain that all channels are open.
9. Connect the DMM to the HI and LO terminals of the
channel 1 input jack, as shown in Figure 4-3.
10. Note the resistance reading on the DMM. Verify that the
reading is <1Ω.
11. Repeat steps 9 and 10 for channels 2-10. Be sure to connect the DMM to the HI and LO input terminals of the
channel being tested. Also, the channel being tested
must be open so that the ground relay is closed.
Out
H
IN 2....9
L
G
H
L
H
L
IN 1
IN 10
Model 6521/22 Card
Note: Model 6521 shown. Model
6522 connections same except
for triax inputs.
Channel 1 connection shown
4-5
Service Information
4.3.7 Isolation tests
These tests check the leakage resistance (isolation) between
all Model 6522 channel input HI and LO terminals, and the
input isolation between the HI and LO terminals of each
channel. In general, the test is performed by applying a voltage from the Model 6517 voltage source across the terminals
and then measuring the isolation resistance using the ohms
function of the electrometer.
NOTE
The isolation tests covered here should be
performed only on the Model 6522 Scanner Card. Isolation values for the Model
6521 Scanner card are not specified.
Channel isolation
Perform the following steps to check channel isolation:
1. With the power off, install the scanner card in the electrometer OPTION SLOT.
2. Turn on the Model 6517 power, and allow the unit to
warm up for at least one hour before making measurements. Make sure the voltage source is turned off.
WARNING
The following steps use high voltage. Be
sure to turn off the Model 6517 voltage
source before making connection
changes.
3. Select the Model 6517 ohms function, choose the 20TΩ
range, and make certain zero check is disabled.
4. Connect the Model 6517 to the channels 1 and 2 HI input terminals, as shown in Figure 4-4.
5. Press the OPTION CARD button, use the CHANNELCLOSURES menu to close channel 1. Program the voltage source for 200V, and then turn on the Model 6517
voltage source.
6. Verify that the Model 6517 resistance reading is >10TΩ.
7. Turn off the voltage source, and open channel 1.
8. Repeat steps 6 through 8 for channels 2 through 10.
(Measure resistance between each channel in succession
and all other channels.)
9. Repeat the entire procedure for channel LO input
terminals.
Input isolation
Perform the following steps to check input isolation:
1. With the power off, install the scanner card in the electrometer OPTION SLOT.
2. Turn on the Model 6517 power, and allow the unit to
warm up for at least one hour before making measurements. Make sure the voltage source is turned off.
WARNING
The following steps use high voltage. Be
sure to turn off the Model 6517 voltage
source before making connection
changes.
3. Select the Model 6517 ohms function, choose the 20GΩ
range, and make certain zero check is disabled.
4. Connect the Model 6517 to the channel 1 HI and LO input terminals, as shown in Figure 4-5.
5. Press the OPTION CARD button, use the CHANNELCLOSURES menu to close channel 1. Program the voltage source for 200V output, and then turn on the Model
6517 voltage source.
6. Verify that the Model 6517 resistance reading is
>10GΩ.
7. Turn off the voltage source, and open channel 1.
8. Repeat steps 5 through 7 for channels 2 through 10.
(Measure resistance between HI and LO of each channel
with that channel closed.)
4-6
Service Information
F
C
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
F
C
WARNING:
NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.
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.
CAUTION:
FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.
Voltage Source LO
!
INPUT
250V PEAK
Model 6517 Electrometer
Note: 1. Configure electrometer for
internal voltage source
connection.
2. Signal LO acts as guard.
igure 4-4
onnections for channel isolation
Triax Cable
DIGITAL
TRIG LINK
I/O
Triax Cable
115V
LINE RATING
Voltage Source HI
LINE FUSE
50-60HZ
SLOWBLOW
50VA MAX
1/2A 90-125V
AC ONLY
1/4A 180-250V
IEEE-488
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
Voltage Source HI
OUT
HI
H
IN 2....9
L
H
IN 1
L
G
G
H
IN 10
L
G
Channel 1 to 10
connections shown
Model 6522 Card
!
INPUT
250V PEAK
Model 6517 Electrometer
igure 4-5
onnections for input isolation
LINE FUSE
LINE RATING
115V
50-60HZ
SLOWBLOW
50VA MAX
1/2A 90-125V
AC ONLY
1/4A 180-250V
IEEE-488
(CHANGE IEEE ADDRESS
WITH FRONT PANEL MENU)
DIGITAL
TRIG LINK
I/O
Note: Configure electrometer for
internal voltage source
connection.
OUT
IN 1
IN 10
HI
LO
H
IN 2....9
L
G
H
L
G
H
L
G
Channel 1
connections shown
Model 6522 Card
4-7
Service Information
F
B
4.4 Special handling of static-sensitive devices
CMOS and other high-impedance devices are subject to possible static discharge damage because of the high-impedance
levels involved. When handling such devices, use the precautions listed below.
NOTE
In order to prevent damage, assume that all
parts are static-sensitive.
1. Such devices should be transported and handled only in
containers specially designed to prevent or dissipate
static build-up. Typically, these devices will be received
in anti-static containers made of plastic or foam. Keep
these parts in their original containers until ready for installation or use.
2. Remove the devices from their protective containers
only at a properly grounded workstation. Also, ground
yourself with an appropriate wrist strap while working
with these devices.
3. Handle the devices only by the body; do not touch the
pins or terminals.
4. Any printed circuit board into which the device is to be
inserted must first be grounded to the bench or table.
5. Use only anti-static type de-soldering tools and
grounded-tip soldering irons.
To 6517
Electrometer
Clock
Data
Strobe
+5V
Relay
Drivers
U102-U104
Power-on
Reset
U105
Enable
Relays
K101-K120
User Connections
igure 4-6
lock diagram
4.5.2 Relay control
Card relays are controlled by serial data transmitted from the
host electrometer via the relay DATA line. A total of three
bytes are shifted in serial fashion into latches located in the
card relay driver ICs (U102- U104). The serial data is
clocked in by the CLK (clock) line. As data overflows one
register, it is fed out the QS line of the register down the
chain.
Once all three bytes have shifted into the card, the STR line
is set high to latch the relay information into the Q outputs of
the relay drivers, and the appropriate relays are energized
(assuming the driver outputs are enabled, as discussed below). Note that a relay driver output goes low to energize the
corresponding relay.
4.5 Principles of operation
The following paragraphs discuss the basic operating principles for the Model 6521/22, and can be used as an aid in troubleshooting the card. The schematic drawings of the scanner
cards are located at the end of Section 5.
4.5.1 Block diagram
Figure 4-6 shows a simplified block diagram of the Model
6521/22. Key elements include the relay data control circuits, the relay drivers and relays, and the power-up reset circuit. These various elements are discussed in the following
paragraphs.
4.5.3 Switching circuits
Signal switching is performed by relays K101 through K120.
Even-numbered relays (K102 through K120) perform the actual signal switching, while odd-numbered relays (K101
through K119) maintain a common path for current switching by maintaining a current path to common when a channel
is open.
4.5.4 Power-on/power-off safeguard
A power-on/power-off safeguard circuit, made up of U105
and associated components ensures that relays do not randomly energize on power-up and power-down. This circuit
disables all relays (all relays are open) during power-up and
power-down periods by holding the OE (output enable) lines
high during these periods.
4-8
Service Information
4.6 Troubleshooting
4.6.1 Troubleshooting equipment
Table 4-2 summarizes recommended equipment for troubleshooting the Model 6521/6522.
Table 4-2
Recommended troubleshooting equipment
Manufacturer/
Description
Multimeter
Oscilloscope
4.6.2 Troubleshooting access
In order to gain access to the scanner card circuit board to
measure voltages under actual operation conditions, perform
the following steps:
1. Turn off the Model 6517 power, and disconnect the line
cord and all other equipment.
Disconnect the line core and all other
equipment from the Model 6517 and the
scanner card before removing the cover.
2. If cables are connected to the scanner card, remove the
scanner card from the electrometer.
3. Remove the Model 6517 cover.
4. Install the scanner card in the electrometer.
5. Disconnect any cables connected to the scanner card
input/output jacks.
6. Connect the line cord, and turn on the power to measure
voltages (see following paragraph).
Model Application
Keithley 2001
TEK 2243
WARNING
DCV checks
View logic waveforms
4.6.3 Troubleshooting procedure
Table 4-3 summarizes scanner card troubleshooting steps.
Refer to the schematic diagrams and component layout
drawings at the end of Section 5 for component locations.
WARNING
Lethal voltages are present within the
Model 6517. Some of the procedures
may expose you to hazardous voltages.
Observe standard safety precautions for
dealing with live circuits. Failure to do
so could result in personal injury or
death.
CAUTION
Observe the following precautions when
troubleshooting or repairing the switch
card:
• To avoid contamination, which could
degrade card performance, always
handle the card only by the side
edges. Do not touch edge connectors,
board surfaces, or components on the
card. Also, do not touch areas
adjacent to electrical contacts on
connectors.
• Use care when removing relays from
the PC board to avoid pulling traces
away from the circuit board. Before
attempting to remove a relay, use an
appropriate de-soldering tool to clear
each mounting hole completely free
of solder. Each relay pin must be free
to move in its mounting hole before
removal. Also, make certain that no
burrs are present on the ends of the
relay pins.
4-9
Service Information
Table 4-3
Troubleshooting procedure
Step Item/component
1
Digital ground P1034, pin 1, 3, 5
2
P1034, pin 9
3
U102, pin 2
4
U102, pin 3
5
U102, pin 7
6
U102-U104, pins 10-18
Required
condition Comments
All voltages referenced to digital ground.
+5VDC
CLK pulses
DATA pulses
STR pulse
Low with relay
Card power supply voltage.
During relay update sequence only.
During relay update sequence only.
End of relay update sequence.
Relay driver outputs. Low with relay energized,
high with relay de-energized.
4-10
5
Replaceable Parts
5.1 Introduction
This section contains replacement parts information, schematic diagrams, and component layout drawings for the
Model 6521/22.
5.2 Parts lists
Parts lists for the scanner cards are included in tables integrated with schematic diagrams and component layout drawings for the boards. Parts are listed alphabetically in order of
circuit designation.
5.3 Ordering information
To place an order, or to obtain information concerning replacement parts, contact your Keithley representative or the
factory (see inside front cover for addresses). When ordering
parts, be sure to include the following information:
• Card model number (6521/22)
• Card serial number
• Part description
• Circuit description, if applicable
• Keithley part number
5.4 Factory service
If the card is to be returned to Keithley Instruments for repair ,
perform the following:
• Call the repair department at 1-800-552-1115 for a
Return Material Authorization (RMA) number.
• Complete the service form at the back of this manual
and include it with the card.
• Carefully pack the card in the original packing carton.
• Write ATTENTION REPAIR DEPT and the RMA
number on the shipping label.
NOTE
It is not necessary to return the Model
6517 Electrometer with the card.
5.5 Component layouts and schematic diagrams
Component layout drawings and schematic diagrams are included on the following pages integrated with the parts lists
for the Model 6521 and Model 6522 Scanner Card.
5-1
Replaceable Parts
Model 6521 Parts List
Circuit Desig. Description Keithley Part No.
C101-106
C107
C108
K101-120
P1034
R101, 102
R103
U101
U102-104
U105
W101
BNC JACK
CABLE ASSEMBL Y
CAP (OUTPUT)
CAP, PROTECTIVE (INPUT 1)
CAP, PROTECTIVE (INPUT 2-10)
CONNECTOR (FOR SC-22)
EPROM PROGRAM
GROMMET, POLYETHYLENE
HANDLE
LOW NOISE COAXIAL CABLE
REAR BRACKET
REAR PANEL
SHIELD
TERMINAL, COAX SHIELD (FOR SC-22 AND SC-36)
TRIAX CABLE (IN1-10)
TRIAX 3 SLOT CABLE PLUG (FOR OUTPUT)
4-40X5/16 PHILLIPS PAN HD SEMS
CAP, .1UF, 20%, 50V, CERAMIC(1206)
CAP, 10UF, 20%, 25V, TANTALUM (D7243)
CAP, 100UF, 20%, 16V, TANTALUM (7243)
RELAY, 1FORMA, COTO 1203-0147
CONNECTOR, FEMALE 48 PIN
RES 4.7K, 5%, 125MW, METAL FILM (1206)
RES, 1K, 5%, 125MW, METAL FILE (1206)
EPROM PROGRAM
IC, 8 STG/SHFT/STR REG, UCN5841LW(SOLIC)
IC, SUPPLY VOLT SUPERVISOR, TL7705A(SOIC)
SHIELDED COAX TEFLON
CS-832
6521-SCAN-1
CAP-28-1
CAP-18
CAP-30-1
CS-810
6521-800A01
GR-34
HH-38
SC-110
6522-304-1A
6522-302A
6522-305-1A
TE-114
SC-22
CS-631
4-40X5/16PPHSEM
C-418-.1
C-440-10
C-504-100
RL-181
CS-826-2
R-375-4.7K
R-375-1K
6521-800*
IC-857
IC-860
SC-36
* Order current firmware revision level.
5-2
Model 6522 Parts List
Circuit Desig. Description Keithley Part No.
Replaceable Parts
C101-106
C107
C108
K101-120
P1034
R101, 102
R103
U101
U102-104
U105
W101
CAP (OUTPUT)
CAP, PROTECTIVE (INPUT 2-10)
CAP, PROTECTIVE (INPUT 1)
CABLE ASSEMBL Y
CONNECTOR
CONNECTOR (FOR SC-22)
GROMMET, POLYETHYLENE
HANDLE
REAR BRACKET
REAR PANEL
SHIELD
TERMINAL, COAX SHIELD (FOR SC-22 AND SC-36)
TRIAX CABLE (IN1-10)
TRIAX 3 SLOT CABLE PLUG (FOR OUTPUT)
4-40X5/16 PHILLIPS PAN HD SEMS
CAP, .1UF, 20%, 50V, CERAMIC(1206)
CAP, 10UF, 20%, 25V, TANTALUM (D7243)
CAP, 100UF, 20%, 16V, TANTALUM (7243)
RELAY, 1FORMA, COTO 1203-0147
CONNECTOR, FEMALE 48 PIN
RES 4.7K, 5%, 125MW, METAL FILM (1206)
RES, 1K, 5%, 125MW, METAL FILM (1206)
EPROM PROGRAM
IC, 8 STG/SHFT/STR REG, UCN5841LW(SOLIC)
IC, SUPPLY VOLT SUPERVISOR, TL7705A(SOIC)
SHIELDED COAX TEFLON
CAP-28-1
CAP-30-1
CAP-31
6522-SCAN-1
CS-829
CS-810
GR-34
HH-38
6522-304-2A
6522-302A
6522-305-2A
TE-114
SC-22
CS-631
4-40X5/16PPHSEM
C-418-.1
C-440-10
C-504-100
RL-181
CS-826-2
R-375-4.7K
R-375-1K
6522-800*
IC-857
IC-860
SC-36
* Order current firmware revision level.
5-3
Replaceable Parts
5-4
Index
B
Block diagram 4-8
Bus scanning 3-7
C
Capacitor leakage measurements 3-11
Card configuration 3-4, 3-7
Card Connections and Installation 2-1
Card installation and removal 2-4
Channel isolation 4-6
Closing and opening channels 3-3, 3-6
Closing channels 3-3, 3-6
Component layouts and schematic
diagrams 5-1
Connections 2-1
D
Dielectric absorption 3-8
E
Electromagnetic interference (EMI) 3-9
Environmental conditions 4-2
F
Factory service 5-1
Features 1-1
Front panel operation 3-2
G
General Information 1-1
Generated currents 3-7
Ground loops 3-9
Ground relay contact resistance tests 4-5
Guarded operation 2-4, 3-10
H
Handling and cleaning precautions 4-1
Handling precautions 1-2, 2-1, 4-1
High-resistance measurements 3-12
I
IEEE-488 bus operation 3-5
IEEE-488 bus scanner commands 3-5
Input connections 2-3
Input isolation 4-6
Inspection for damage 1-2
Instruction manual 1-2
Introduction 4-1
Isolation tests 4-6
K
Keeping connectors clean 3-10
M
Magnetic fields 3-9
Manual addenda 1-2
Measurement considerations 3-7
Model 6521 accessories 1-2
Model 6521 features 1-1
Model 6521 scanner card configuration 2-1
Model 6521 signal limitations 3-1
Model 6521 simplified schematic 2-1
Model 6522 accessories 1-3
Model 6522 connecting cables 2-2
Model 6522 features 1-1
Model 6522 scanner card configuration 2-2
Model 6522 signal limitations 3-1
Model 6522 simplified schematic 2-2
N
Noise 3-9
O
Offset current tests 4-3
Offset currents 3-7
Opening channels 3-3, 3-6
Operation 3-1
Optional accessories 1-2
Ordering information 5-1
Output connections 2-3
Output connections to electrometer 2-7
P
Parts lists 5-1
Path isolation 3-8
Performance verification 4-2
Power-on/power-off safeguard 4-8
Power-up detection 3-2
Principles of operation 4-8
R
Recommended verification equipment 4-2
Relay control 4-8
Relay operation 3-2
Repacking for shipment 1-2
Replaceable Parts 5-1
S
Safety symbols and terms 1-2
Scan control and configuration menus 3-2
Scan method 3-7
Scan mode 3-4
Scanner card connections 4-2
Scanner card detection 3-2
Scanner card installation 2-5
Scanner card removal 2-7
Scanner option bus query 3-2
Scanning controls 3-2
Scanning procedure 3-5
Selecting scan list channels 3-4
Service Information 4-1
i-1
Setting the voltage source limit 3-4, 3-7
Settling time 3-4, 3-7
Shipment contents 1-2
Signal limitations 3-1
Signal path contact resistance tests 4-4
Soldering considerations 4-1
Special handling of static-sensitive
devices 4-8
Specifications 1-2
Switching circuits 4-8
T
Triboelectric effects 3-8
Troubleshooting 4-9
Troubleshooting access 4-9
Troubleshooting equipment 4-9
Troubleshooting procedure 4-9
Typical applications 3-11
Typical connecting schemes 2-3
U
Unpacking and inspection 1-2
W
Warranty information 1-1
i-2
Service Form
Model No. Serial No. Date
Name and Telephone No.
Company
List all control settings, describe problem and check boxes that apply to problem.
❏ Intermittent ❏ Analog output follows display ❏ Particular range or function bad; specify
❏ IEEE failure ❏ Obvious problem on power-up ❏ Batteries and fuses are OK
❏ Front panel operational ❏ All ranges or functions are bad ❏ Checked all cables
Display or output (check one)
❏ Drifts ❏ Unable to zero
❏ Unstable ❏ Will not read applied input
❏ Overload
❏ Calibration only ❏ Certificate of calibration required
❏ Data required
(attach any additional sheets as necessary)
Show a block diagram of your measurement system including all instruments connected (whether power is turned on or not).
Also, describe signal source.
Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.)
What power line voltage is used? Ambient temperature? °F
Relative humidity? Other?
Any additional information. (If special modifications have been made by the user, please describe.)
Be sure to include your name and phone number on this service form.
Specifications are subject to change without notice.
All Keithley trademarks and trade names are the property of Keithley Instruments, Inc. All other
trademarks and trade names are the property of their respective companies.
Keithley Instruments, Inc. 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168
1-888-KEITHLEY (534-8453) www .keithley.com
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© Copyright 2000 Keithley Instruments, Inc. No. 2193
Printed in the U.S.A. 2/2000
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