Keithley 7999-3 Service manual

Model 7999-3

Multiplexer Card

Instruction Manual

Contains Operating and Servicing Information

W ARRANTY

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.

LIMIT A TION OF W ARRANTY

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

CHINA: Keithley Instruments China • Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-62022886 • Fax: [phone]
FRANCE: Keithley Instruments SARL • BP 60 • 3 Allée des Garays • 91122 Palaiseau Cédex • 33-1-60-11-51-55 • Fax: [phone]
GERMANY: Keithley Instruments GmbH • Landsberger Strasse 65 • D-82110 Germering, Munich • 49-89-8493070 • Fax: [phone]
GREAT BRITAIN: Keithley Instruments, Ltd. • The Minster • 58 Portman Road • Reading, Berkshire RG30 1EA • 44-118-9575666 • Fax: [phone]
ITALY: Keithley Instruments SRL • Viale S. Gimignano 38 • 20146 Milano • 39-2-48303008 • Fax: [phone]
NETHERLANDS: Keithley Instruments BV • Avelingen West 49 • 4202 MS Gorinchem • 31-(0)183-635333 • Fax: [phone]
SWITZERLAND: Keithley Instruments SA • Kriesbachstrasse 4 • 8600 Dübendorf • 41-1-8219444 • Fax: [phone]
TAIWAN: Keithley Instruments Taiwan • 1FL., 85 Po Ai Street • Hsinchu, Taiwan • 886-3-572-9077 • Fax: [phone]

1/99

Model 7999-3 Single-Pole Multiplexer Card

Instruction Manual

©1999, Keithley Instruments, Inc.

All rights reserved.
Cleveland, Ohio, U.S.A.
First Printing, May 1999

Document Number: 7999-3-901-01 Rev. A

Manual Print History

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

Revision A (Document Number 7999-3-901-01)..............................................................May 1999

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

Safety Precautions

The following safety precautions should be observed before using this product and any associated instrumen­tation. Although some instruments and accessories would normally be used with non-hazardous v oltages, 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 is the individual or group responsible for the use and maintenance of equipment, for ensuring

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

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

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

Maintenance personnel perform routine procedures on the product to keep it operating, 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 are trained to work on live circuits, and perform safe installations and repairs of products.

Only properly trained service personnel may perform installation and service procedures.
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 e xists when
voltage levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect

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

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, no conductive part

of the circuit may be exposed.

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multimeter
measuring circuits (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) are Installation Category II.
All other instruments’ signal terminals are Installation Category I and must not be connected to mains.

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.

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 an y capacitors before:
connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal
changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power
line (earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface ca­pable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with 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 heading in a 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 in a manual explains hazards that could damage the instrument. Such damage may
invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.

To maintain protection from electric shock and fire, 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.

T o clean an instrument, use a damp cloth or mild, water based cleaner . Clean the e xterior 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.

Rev. 2/99

7999-3 Single-Pole Multiplexer Card

User
Supplied
Voltage

Relay
Control
Input

Relay
Coil

Card

RELAY SWITCH CONFIGURATION:

10 channels of independent 1-pole switching
1 channel of 2:1 mux 1-pole switching.
2 channels of 4:1 mux 1-pole switching.

CONTACT CONFIGURATION: 1-pole Form A.
CONNECTOR TYPE: 96-pin male DIN card connector.
MAXIMUM SIGNAL: 30V DC, 42V peak between any two inputs or

chassis, 1A switched, CAT I.

CONTACT LIFE: Cold Switching: 10 × 10

CHANNEL RESISTANCE (per conductor): <0.5Ω.
CONTACT POTENTIAL: <10µV per contact.
ACTUATION TIME: 3ms.
RELAY DRIVE CURRENT (per relay): 8.5mA @ 24V (user supplied).
USER SUPPLIED VOLTAGE: 24V ± 4V DC, 220mA max.
RELAY CONTROL INPUT: Relay Closed: <2.0V.

RELAY DRIVE CONFIGURATION:

At Maximum Signal Levels: 2 × 10

Relay Open: User supplied voltage.

6

closures.

5

closures.

GENERAL

INDICATORS: SMT LED shows status of each relay.
ENVIRONMENT: Operating: 0° to 50°C, up to 35°C <80% RH.

EMC: Conforms with European Union Directive 89/336/EEC, EN

55011, EN 50082-1, EN 61000-3-2 and 61000-3-3, FCC part 15
class B.

SAFETY: Conforms with European Union Directive 73/23/EEC, EN

61010-1.

DIMENSIONS: 160mm long × 108mm wide ×38mm deep (6

1

× 1

⁄

2

˝). PC board is 152mm long × 102mm wide (6˝ × 4˝).

Storage: –25° to 65°C.

5

1

⁄

16

˝ × 4

⁄4˝

1-Pole Switch IN

OUT

2:1 MUX Switch IN 1

IN 2

OUT

4:1 MUX Switch IN 1

IN 2

IN 3

IN 4

OUT

SBG 8/11/99

Rev. A

T able of Contents

1 General Information

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

Feature overview ........................................................................ 1-2

Warranty information ................................................................. 1-2

Manual addenda ......................................................................... 1-2

Safety symbols and terms .......................................................... 1-3

Specifications ............................................................................. 1-3

Unpacking and inspection .......................................................... 1-3

Inspecting for damage ......................................................... 1-3

Handling precautions .......................................................... 1-3

Shipment contents ............................................................... 1-4

Instruction manual .............................................................. 1-4

Repacking for shipment ...................................................... 1-4

Recommended connector ........................................................... 1-4

2 Connections

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

Handling precautions ................................................................. 2-2

Card configuration ...................................................................... 2-2

Card layout .......................................................................... 2-2

Simplified schematic ........................................................... 2-4

Card connections ........................................................................ 2-7

Input/output connector ........................................................ 2-7

Terminal designations ......................................................... 2-7

Controlling relays ................................................................ 2-8

3 Operating Considerations

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

Maximum signal considerations ................................................ 3-2

Relay power and control ............................................................ 3-2

Switching considerations ........................................................... 3-2

Keeping the input/output connector clean .......................... 3-2

RFI/EMI .............................................................................. 3-3

Ground loops ....................................................................... 3-3

4 Service Information

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

Handling and cleaning precautions ............................................ 4-2

Handling precautions ........................................................... 4-2

Card cleaning ....................................................................... 4-2

Performance verification ............................................................. 4-3

Environmental conditions .................................................... 4-3

Recommended equipment ................................................... 4-3

Multiplexer card connections .............................................. 4-3

Channel resistance tests ....................................................... 4-4

Contact potential tests ......................................................... 4-5

Replacing components ................................................................ 4-6

Replacement parts ............................................................... 4-6

Replacement precautions ..................................................... 4-6

Soldering considerations ..................................................... 4-6

5 Replaceable Parts

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

Parts list ...................................................................................... 5-2

Ordering information .................................................................. 5-2

Factory service ............................................................................ 5-2

Component layout and schematic diagram ................................. 5-3

List of Illustrations

2 Connections

Figure 2-1 Card configuration .................................................................. 2-3

Figure 2-2 Simplified schematic............................................................... 2-5

Figure 2-3 J1 connector terminal designations......................................... 2-7

3 Operating Considerations

Figure 3-1 Ground loops .......................................................................... 3-3

Figure 3-2 Eliminating ground loops ....................................................... 3-4

4 Service Information

Figure 4-1 Channel resistance test connections........................................ 4-4

Figure 4-2 Contact potential connections................................................. 4-5

List of T ables

2 Connections

Table 2-1 Card relay channel summary .................................................. 2-3

Table 2-2 Signal terminals ...................................................................... 2-6

Table 2-3 Control line terminals ............................................................. 2-8

4 Service Information

Table 4-1 Recommended verification equipment ................................... 4-3

5 Replaceable Parts

Table 5-1 Parts list................................................................................... 5-3

1

General Information

1-2 General Information

Introduction

This section contains general information about the Model 7999-3 Single-Pole Multiplexer
Card. This information is organized as follows:

• Feature overview

• Warranty information

• Manual addenda

• Safety symbols and terms

• Specifications

• Unpacking and inspection

• Recommended connector

If you have any questions after reviewing this information, please contact your local
Keithley representative or call one of our Applications Engineers at 1-800-348-3735 (U.S. and
Canada only). Worldwide phone numbers are listed at the front of this manual.

Feature overview

The Model 7999-3 is a single-pole multiplexer card with the following features:

• 10 channels of independent 1-pole switching

• One channel of 2:1 multiplexer 1-pole switching

• Two channels of 4:1 multiplexer 1-pole switching

• External relay control and +24V DC power connections

• 96-pin male DIN connector for card connections

• LED indicator shows the status of each relay

W arranty information

Warranty information is located at the front of this instruction manual. Should your Model
7999-3 require warranty service, contact the Keithley representative or authorized repair facil­ity in your area for further information. When returning the card for repair, be sure to fill out
and include the service form at the back of this manual to provide the repair facility with the
necessary information.

Manual addenda

Any improvements or changes concerning the card or manual will be explained in an adden­dum included with this manual. Be sure to note these changes and incorporate them into the
manual.

General Information 1-3

Safety symbols and terms

The following symbols and terms may be found on the multiplexer card or used in this

manual.

The symbol indicates that the user should refer to the operating instructions located in

!

the manual.

The

symbol

safety precautions to avoid personal contact with these voltages.

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.

shows that high voltage may be present on the terminal(s). Use standard

The

CAUTION heading used in this manual explains hazards that could damage the

multiplexer card. Such damage may invalidate the warranty.

Specifications

Full Model 7999-3 specifications are included at the front of this manual.

Unpacking and inspection

Inspecting for damage

The Model 7999-3 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.

Handling precautions

• Always grasp the card by the side edges and covers. Do not touch the connector insula­tor, board surfaces, or components.

• 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 and connected, keep the card in its anti-static bag, and
store it in the original packing carton.

1-4 General Information

Shipment contents

The following items are included with every Model 7999-3 order:

• Model 7999-3 Single-Pole Multiplexer Card

• Model 7999-3 Instruction Manual

• Additional accessories as ordered

Instruction manual

If an additional Model 7999-3 Instruction Manual is required, order the manual package,
Keithley part number 7999-3-901-01. The manual package includes an instruction manual and
any pertinent addenda.

Repacking for shipment

Should it become necessary to return the Model 7999-3 for repair, carefully pack the unit in
its original packing carton or the equivalent, and include the following information:

• Call the Repair Department at 1-800-552-1115 for a Return Material Authorization
(RMA) number.

• Advise as to the warranty status of the card.

• Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping
label.

• Fill out and include the service form located at the back of this manual.

Recommended connector

The following mating receptacle is recommended for use with the Model 7999-3 96-pin

connector:

• AMP 216081-8 series 96 pin DIN receptacle

2

Connections

2-2 Connections

Introduction

This section contains information about overall card configuration and connections and is

organized as follows:

• Handling precautions

• Card configuration

• Connections

WARNING The procedures in this section are intended only for qualified service per-

sonnel. 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.

Handling precautions

To maintain high-impedance isolation between channels, care should be taken when han­dling the card to avoid contamination from such foreign materials as body oils and salts. Such
contamination can reduce isolation resistance. To avoid possible contamination:

• Always grasp the card by the side edges.

• Do not touch board surfaces, components, or connector insulators.

• Operate the card in a clean en vironment. If the card becomes contaminated, it should be
thoroughly cleaned as explained in Section 4.

Card configuration

Card layout

Figure 2-1 shows the general layout of the Model 7999-3. Items include:

• Input/output connector (J1) — All input/output signal, control, and power connections
to the card are made through this connector. See Figure 2-3, Table 2-2, and Table 2-3
for terminal designations.

• Indicator lights — One LED for each relay indicates when that relay is energized.

• Relays (20) — These relays provide card switching for the independent channels, the
2:1 mux, and both 4:1multiplexers as summarized in Table 2-1.

Fi

1

Connections 2-3

Table 2-1

Card relay channel summary

Relay Channel designation Description

K1 through K6 1 through 6 Independent channels
K7 and K8 7/1 and 7/2 2:1 mux channels
K9 through K12 8/1 through 8/4 4:1 mux #1 channels
K13 through K16 9/1 though 9/4 4:1 mux #2 channels
K17 +12V +12V channel
K18 through K20 Spare channels

gure 2-

Card configuration

Input/Output

Connector

J1

9/4

K16

8/3

K11

6

1

K1

Indicator Lights

(1 per Relay)

+12V

K17
8/4

K12

7/1

K7 K8 K9 K10K6

2

K2

Relays (20)

See Text for Description

K18

9/1

K13

7/2

3

K3

K19

9/2

K14
8/1

4

K4

K20

9/3

K15

8/2

5

K5

2-4 Connections

Simplified schematic

paths (see Table 2-3 for a summary of control signals). Note that J1 terminal designations are
also shown on the diagram. Key sections include:

Figure 2-2 shows a simplified schematic diagram of the Model 7999-3 showing only signal

• Independent channels 1 - 6

• 2:1 multiplexer

• Two 4:1 multiplexers

• +12V channel

• Three spare channels

Fi

2

Connections 2-5

gure 2-

Relay 1 In (C8)

K1 1

Relay 1 Out (C9)

Simplified
schematic

Relay 2 In (C10)

Relay 3 In (C12)

Relay 4 In (C14)

Relay 5 In (C16)

Relay 6 In (C18)

K2 2

K3 3

K4 4

K5 5

K6 6

Relay 2 Out (C11)

Relay 3 Out (C13)

Relay 4 Out (C15)

Relay 5 Out (C17)

Relay 6 Out (C19)

Independent

Channels

Relay 7 In1 (C20)

Relay 7 In2 (C21)

Relay 8 In1 (C23)

Relay 8 In2 (C24)

Relay 8 In3 (C25)

Relay 8 In4 (C26)

K7 7/1

K8 7/2

K9 8/1

K10 8/2

K11 8/3

K12 8/4

Relay 7 Out (C22)

2:1 Mux

Relay 8 Out (C27)

4:1 Mux

Relay 9 In1 (C28)

Relay 9 In2 (C29)

Relay 9 In3 (C30)

Relay 9 In4 (C31)

DC+12 Out (A24)

Spare 1 In (A25)

Spare 2 In (A27)

Spare 3 In (A29)

NOTE: J1 terminals in parentheses.

K13 9/1

K14 9/2

K15 9/3

K16 9/4

K17

K18

K19

K20

Relay 9 Out (C32)

DC2 (+12V) (A23)

Spare 1 Out (A26)

Spare 2 Out (A28)

Spare 3 Out (A30)

4:1 Mux

+12V Channel

Spare Channels

2-6 Connections

Table 2-2

Signal terminals

Signal Description J1 terminal*

RELAY 1 IN Channel 1 input C8
RELAY 1 OUT Channel 1 output C9
RELAY 2 IN Channel 2 input C10
RELAY 2 OUT Channel 2 output C11
RELAY 3 IN Channel 3 input C12
RELAY 3 OUT Channel 3 output C13
RELAY 4 IN Channel 4 input C14
RELAY 4 OUT Channel 4 output C15
RELAY 5 IN Channel 5 input C16
RELAY 5 OUT Channel 5 output C17
RELAY 6 IN Channel 6 input C18
RELAY 6 OUT Channel 6 output C19
RELAY 7 IN1 2:1 mux input #1 C20
RELAY 7 IN2 2:1 mux input #2 C21
RELAY 7 OUT 2:1 mux output C22
RELAY 8 IN1 4:1 mux #1 input #1 C23
RELAY 8 IN2 4:1mux #1 input #2 C24
RELAY 8 IN3 4:1 mux #1 input #3 C25
RELAY 8 IN 4 4:1 mux #1 input #4 C26
RELAY 8 OUT 4:1 mux #1 output C27
RELAY 9 IN1 4:1 mux #2 input #1 C28
RELAY 9 IN2 4:1 mux #2 input #2 C29
RELAY 9 IN3 4:1 mux #2 input #3 C30
RELAY 9 IN4 4:1 mux #2 input #4 C31
RELAY 9 OUT 4:1 mux #1 output C32
DC2(+12V) External +12V input A23
DC+12 OUT +12V output A24
SPARE 1 IN Spare #1 input A25
SPARE 1 OUT Spare #1 output A26
SPARE 2 IN Spare #2 input A27
SPARE 2 OUT Spare #2 output A28
SPARE 3 IN Spare #3 input A29
SPARE 3 OUT Spare #3 output A30

*See Figure 2-3 for J1 pinouts.

Fi

3

Card connections

Input/output connector

Figure 2-3 shows the terminal configuration for the input/output connector (J1). The connec­tor is organized into three rows, labelled A, B, C, and each row has 32 pins, designated 1
through 32.

Connections 2-7

gure 2-

J1 connector
terminal
designations

T erminal designations

1 32

A
B
C

J1 (Terminal Side)

Signal terminals

Table 2-2 summarizes signal terminal designations. These designations are also shown on
the simplified schematic in Figure 2-2.

Control terminals

Table 2-3 lists control terminal designations. A relay is energized by setting the correspond­ing control line low.

2-8 Connections

+24V power terminals

Table 2-3

Control line terminals

**Set control line low to close channel. See Table 2-2 for a summary of signals and channels.

**See Figure 2-3 for J1 pinouts.

To power the relays, +24V DC must be applied to either of the following terminals of J1:
A31 or A32

Control or power line* Relay Switched signal* J1 terminal**

CONTROL 1 K1 RELAY 1 (Channel 1) A1
CONTROL 2 K2 RELAY 2 (Channel 2) A2
CONTROL 3 K3 RELAY 3 (Channel 3) A3
CONTROL 4 K4 RELAY 4 (Channel 4) A4
CONTROL 5 K5 RELAY 5 (Channel 5) A5
CONTROL 6 K6 RELAY 6 (Channel 6) A6
CONTROL 7 K7 RELAY 7 IN1 (7/1) A7
CONTROL 8 K8 RELAY 7 IN2 (7/1) A8
CONTROL 9 K9 RELAY 8 IN1 (8/1) A9
CONTROL 10 K10 RELAY 8 IN2 (8/2) A10
CONTROL 11 K11 RELAY 8 IN3 (8/3) A11
CONTROL 12 K12 RELAY 8 IN4 (8/4) A12
CONTROL 13 K13 RELAY 9 IN1 (9/1) A13
CONTROL 14 K14 RELAY 9 IN2 (9/2) A14
CONTROL 15 K15 RELAY 9 IN3 (9/3) A15
CONTROL 16 K16 RELAY 9 IN4 (9/4) A16
CONTROL 17 K17 DC2 (+12V) A17
CONTROL 18 K18 SPARE 1 A18
CONTROL 19 K19 SPARE 2 A19
CONTROL 20 K20 SPARE 3 A20

Controlling relays

T o control relays, an e xternal +24V DC v oltage source must be connected to pin A31 or A32

of J1. A relay is energized by setting the corresponding control signal low (Table 2-3).

3

Operating Considerations

•

•

3-2 Operating Considerations

Introduction

This section contains information about operating considerations for the Model 7999-3

Single-Pole Multiplexer Card. The information is organized as follows:

• Maximum signal considerations

• Relay power and control

• Switching considerations

Maximum signal considerations

CAUTION T o prevent damage to the Model 7999-3, do not exceed the following maxi-

mum signal level specifications of the card:

Maximum voltage: 30V DC, 42V Peak
Maximum current: 1A DC, switched

Relay power and control

To control relays, an external +24V DC voltage source must be connected to either the A31
or A31 terminal of J1. A relay is energized by setting the corresponding control signal low (see
Table 2-3).

Switching considerations

Signals that pass through the Model 7999-3 are subject to various effects that can seriously
affect their integrity. The following paragraphs discuss these effects and ways to minimize
them.

Keeping the input/output connector clean

As is the case with any high-resistance device, the integrity of the 96-pin input/output con­nector (J1) can be compromised if it is not handled properly. If connector insulation becomes
contaminated, the insulation resistance will be substantially reduced, affecting high-impedance
measurement paths.

Oils and salts from the skin can contaminate connector insulator, reducing its resistance.
Also, contaminants present in the air can be deposited on the insulator surface. To avoid these
problems, never touch the connector insulating material. In addition, the multiplexer card
should be used only in clean, dry environments to avoid contamination.

Fi

1

Operating Considerations 3-3

If the connector insulator should become contaminated, either by inadvertent touching, or
from air-borne deposits, it can be cleaned with a cotton swab dipped in clean methanol. After
thorough cleaning, the connector should be allowed to dry for several hours in a low-humidity
environment before use, or it can be dried more quickly using dry nitrogen.

RFI/EMI

RFI (Radio Frequency Interference) and EMI (Electromagnetic Interference) are general
terms used to describe electromagnetic interference over a wide range of frequencies across the
spectrum. Such interference can be particularly troublesome at low signal le v els, b ut it can also
affect measurements at high levels if the problem is of sufficient severity.

EMI can be caused by steady-state sources such as radio or TV broadcast signals, or some
types of electronic equipment (microprocessors, high speed digital circuits, etc.), or it can
result from impulse sources, as in the case of arcing in high-voltage environments. In either
case, the effect on the desired signal can be considerable if enough of the unwanted signal is
present.

EMI can be minimized in several ways. The most obvious method is to keep the equipment
and signal leads as far away from the RFI source as possible. Shielding the multiplexer card,
signal leads, sources, and measuring instruments will often reduce RFI to an acceptable level.
In extreme cases, a specially-constructed screen room may be required to suf ficiently attenuate
the troublesome signal.

Ground loops

When two or more devices are connected together, care must be taken to avoid unwanted
signals caused by ground loops. Ground loops usually occur when devices are connected with
more than one signal return path such as power line ground. As shown in Figure 3-1, the result­ing ground loop causes current to flow through 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 devices. This voltage will be induced into the desired signal, affecting its
integrity.

gure 3-

Ground loops

Device 1

Ground Loop

Current

Signal Leads

Device 2

Power Line Ground

Device 3

Fi

2

3-4 Operating Considerations

Figure 3-2 shows how to connect several devices together to eliminate this type of ground

loop problem. Here, only one device is connected to power line ground.

Ground loops are not normally a problem with isolated LO terminals. However, all devices
in the test setup may not be designed in this manner . When in doubt, consult the manual for all
instrumentation in the test setup.

gure 3-

Eliminating
ground loops

Device 1

Device 2

Power Line Ground

Device 3

4

Service Information

4-2 Service Information

Introduction

This section contains service information for the Model 7999-3. The information is orga­nized as follows:

• Handling and cleaning precautions

• Performance verification

• Component replacement

WARNING The information in this section is intended only for qualified service per-

sonnel. Some of the procedures may expose you to hazardous voltages that
could result in personal injury or death. Do not perform these procedures
unless you are qualified to do so.

Handling and cleaning precautions

Because of the high-impedance areas on the Model 7999-3, care should be taken when
handling or servicing the card to prevent possible contamination. The following precautions
should be observed when servicing the card.

Handling precautions

Observe the following precautions when handling the multiplexer card:

• Handle the card only by the edges.

• Do not touch connector insulator.

• 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 en vironment where dust could settle on the circuit
board.

Card cleaning

• Use dry nitrogen gas to clean any dust off the circuit board and components.

• Clean the contaminated area with methanol, then blow dry the entire board with dry
nitrogen gas.

• After cleaning, allow the card to dry in a 50˚C low-humidity environment for several
hours before use.

Service Information 4-3

Performance verification

The following paragraphs discuss performance verification procedures for the Model

7999-3, including channel resistance and contact potential.

CAUTION Contamination will degrade the performance of the card. To avoid con-

tamination, always grasp the card by the side edges. Do not touch the
input/output connector insulator, and do not touch the board surfaces or
components.

NOTE F ailur e of any performance verifi cation test may indicate that the multiple xer card is

contaminated. See “Handling and cleaning precautions” earlier in this section for
information on cleaning the card.

Environmental conditions

All verification measurements should be made at an ambient temperature between 18˚ and

28˚C, and at a relative humidity of less than 70%.

Recommended equipment

Table 4-1 summarizes the equipment necessary for performance verification, along with an

application for each item.

Table 4-1

Recommended verification equipment

Description Manufacturer/Model Specifications Test

Digital Multimeter Keithley 2010 10 Ω range, 60ppm Channel resistance
Nanovoltmeter Keithley 2182 10mV range, 50ppm Contact potential
Test Lead Sets (2) Keithley 1681 Banana plug/clips Channel resistance
Low Thermal Cable Keithley 2107-4 Low thermal/lugs Contact potential

Multiplexer card connections

Test equipment connection diagrams in this section are generic in nature and are intended
only to show basic connections on how to connect test equipment to the relay under test. See
Section 2 for complete details on card connections and terminal designations.

Fi

1

Ω

Ω

Ω

Ω

4-4 Service Information

Channel resistance tests

Perform the following steps to verify that each contact of e v ery relay is closing properly and

that the channel resistance is within specification.

1. Turn on the Model 2010 DMM, and allow it to warm up for one hour before making
measurements.

2. Set the Model 2010 to the 10
SENSE

3. Short the free ends of the four test leads together , and enable REL on the Model 2010 to
null out residual resistance. Leave REL enabled for the entire test.

4. Connect the Model 2010 INPUT and SENSE
as shown in Figure 4-1. Note that 4-wire connections to the relay input and output ter­minals are used.

5. Close the relay being tested.

6. Note the resistance reading on the Model 2010, and verify that it is <0.5

7. Open the relay being tested

8. Repeat steps 4 through 7 for every relay on the card.

range, and connect the four test leads to the INPUT and

4 WIRE jacks.

4 WIRE jacks to the relay to be tested,

.

gure 4-

Channel resistance test
connections

Connect to INPUT and SENSE

Relay

In

Close
Relay

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

HOLD TRIG FAST MED SLOW AUTO ERR

MX+B

SHIFT

DCV

LOCAL

EX TRIG

POWER

SAVE SETUP

OPEN CLOSE

SENSE

INPUT

Ω 4 WIRE

CH1REM

SCAN

REL FILT4WBUFFER

dBm

%

dB

ACI

ACV

DCI

HOLD

LIMITS ON/OFFDELAY

TRIG

STORE

RECALL

CONFIG HALT

STEP SCAN

MATH
REAR

STAT

CONT PERIOD SENSOR

FREQ

Ω2 Ω4

TYPE

DRYCKT O COMP

RATIO

RELFILTER

RS232

CAL TEST

GPIB

EXIT ENTER

DIGITS RATE

2010 MULTIMETER

TEMP

HI

350V

1000V

!

PEAK

PEAK

LO

500V
PEAK

INPUTS

F

R

RANGE

AUTO

FRONT/REAR

3A 250V

RANGE

AMPS

Relay

Out

Model 2010 DMM

Model 7999-3 Relay
Under Test. See Section 2
for Detailed Connections.

Fi

2

µ

Contact potential tests

Perform the following procedure to check contact potential of each relay:

1. Connect the low-thermal cable to the Model 2182 Nanovoltmeter INPUT jack.

2. Turn on the Model 2182, and allow the unit to warm up for one hour to achieve rated
accuracy.

3. Select the Model 2182 10mV range.

4. Temporarily short the Channel 1 HI and LO leads of the low-thermal cable.

5. Enable REL on the Model 2182.

6. Connect the Model 2182 to the relay being tested, as shown in Figure 4-2. Be sure to
make connections to the Channel 1 input terminals, and use that channel for measure­ments.

7. Close the relay being tested.

8. Verify that the Model 2182 reading is <10

9. Open the relay being tested.

10. Repeat steps 6 through 9 for all relays on the card.

Service Information 4-5

V.

gure 4-

Contact potential
connections

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

HOLD TRIG FAST MED SLOW AUTO ERR

MX+B

SHIFT

DCV1

DELAY

LOCAL

EX TRIG

POWER

CONFIG HALT

STEP SCAN

CHANNEL 1

LO

TYPE A

OUTPUT

FILT REL

LIMITS

ON/OFFVALUE

RS232

GPIB

DIGITS RATE

MATH
REAR

BUFFER

STAT

2182 NANOVOLTMETER

OUT

TEMP

1

CAL TEST

EXIT ENTER

4W

TCOUPL

TEMP

2

SCAN

CH1REM

REL FILT

V1-V

2

%

ACAL

DCV2

1

/

V

2

V

HOLD

BUFFER

TRIG

STORE

RECALL

SETUP

SAVE RESTR

RANGE

RANGE

AUTO

HI

HI

CHANNEL 2

120V MAX

12V MAX

350V PEAK ANY TERMINAL
TO TERMINAL OR CHASSIS

!

LO

Low Thermal Cable

Connect to and use
Channel 1

Relay In

Close
Relay

Relay Out

Model 2182 Nanovoltmeter

Model 7999-3 Relay
Under Test. See Section 2
for Detailed Connections.

•

•

4-6 Service Information

Replacing components

Replacement parts

Replacement parts can be obtained directly from Keithley Instruments, Inc. See the parts list

in Section 5 for part numbers.

Replacement precautions

CAUTION Observe the following precautions when replacing components:

To avoid contamination, which could degrade card performance,
always handle the card only by the handle and side edges. Do not
touch the connector, board surfaces, or components on the card.

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.

Soldering considerations

When using 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.

• Once the flux has been removed, sw ab only the repaired area with methanol, then blow
dry the board with dry nitrogen gas.

• After cleaning, allow the card to dry in a 50˚C low-humidity environment for several
hours before use.

5

Replaceable Parts

5-2 Replaceable Parts

Introduction

This section contains replacement parts information and component layout and schematic

drawings for the Model 7999-3.

Parts list

The parts list for the Model 7999-3 is shown in Table 5-1.

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 (Model 7999-3)

• Card serial number

• Part description

• Component designation (if applicable)

• Keithley part number

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 instrument in the original packing carton.

• Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping
label.

Ω

Replaceable Parts 5-3

Component layout and schematic diagram

These component layout and schematic diagram drawings are provided on the following

pages:

• Component layout drawing: 7999-3-100

• Schematic diagram: 7999-3-106

Table 5-1

Parts list

Circuit designation Description Keithley part no.

CR1 - CR20 Diode, BAV103 RF-89
DS1 - DS20 LED PL-72-1
J1 Receptacle, 96-pin male CS-514-1
K1 - K20 Relay, EB2-24NU RL-233
R1 - R20 Resistor, 150k

R-376-150K

Index

Symbols

+24V power terminals

2-8

C

Card cleaning
Card configuration
Card connections
Card layout
Channel resistance tests
Component layout and schematic diagram
Connections
Contact potential tests
Control terminals
Controlling relays

2-2

2-1

4-2

2-2

2-7

4-4

4-5

2-7

2-8

E

Environmental conditions

4-3

F

Factory service
Feature overview

5-2

1-2

G

General Information
Ground loops

1-1

3-3

H

Handling and cleaning precautions
Handling precautions

1-3

2-2

,

M

Manual addenda
Maximum signal considerations
Multiplexer card connections

1-2

3-2

4-3

O

Operating Considerations
Ordering information

3-1

5-2

P

Parts list
Performance verification

5-3

5-2

4-3

R

Recommended connector
Recommended equipment
Relay power and control
Repacking for shipment
Replaceable Parts
Replacement parts
Replacement precautions
Replacing components
RFI/EMI

3-3

1-4

4-3

3-2

1-4

5-1

4-6

4-6

4-6

S

Safety symbols and terms
Service Information
Shipment contents
Signal terminals
Simplified schematic

4-2

4-2

,

Soldering considerations
Specifications
Switching considerations

1-3

1-3

4-1

1-4

2-7

2-4

4-6

3-2

I

Input/output connector
Inspecting for damage
Instruction manual
Introduction

1-2

2-7

1-3

1-4

2-2

3-2

,

,

,

K

Keeping the input/output connector clean

4-2

T

Terminal designations

5-2

,

3-2

U

Unpacking and inspection

W

Warranty information

2-7

1-3

1-2

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

❑

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

IEEE failure
Front panel operational ❑ All ranges or functions are bad

Analog output follows display

Obvious problem on power-up

Particular range or function bad; specify

_______________________________

Batteries and fuses are OK
Checked all cables

Display or output (check one)

Drifts
Overload

Calibration only

(attach any additional sheets as necessary)
Show a block diagram of your measurement 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.

Unable to zero
Will not read applied input

Certificate of calibration required

Unstable

Data required

Keithley Instruments, Inc.

28775 Aurora Road
Cleveland, Ohio 44139

Printed in the U.S.A.