Keithley 7154 Instruction Manual

Model 7154

2-Pole High Voltage Scanner Card

Instruction Manual

Contains Operating and Servicing Information

WARRANTY

Model 7154 2-Pole High Voltage

Scanner Card

instruction Manual

B 1988, Kcithlcy Instruments, Inc.

Test Instrumentation Croup

All rights reserved.

Cleveland, Ohio, U.S.A.

March

1988, First Printing

document Numhcr: 7154-901-01 Rev. A

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 precaution8 required to
avoid possible injury. Read the operating information carefully before us­ing the product.

Exercise extreme caution when a shock hazard is present. Lethal voltage
may be present on cable connector jacks or test fixtures. The American
National Standards Institute (ANSI) states that a shock hazard exists
when voltage levels greater than 30V RMS, 42.4V peak, or 60VDC are
present. A good safety practice is to expect that hazardous voltage is
present in any unknown circuit before measuring.

Before operating an instrument, make pure 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 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
mcasurcmcnts with dry hands while standing on a dry, insulated surface
capable of withstanding the voltage being measured.

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 rear panel, or switching card.

Do not connect switching cards directly to unlimited power circuits. They
arc intended to be used with impedance limited sources. NEVER connect
switching cards directly to AC main. When connecting sources to switch­ing cards, install protective devices to limit fault current and voltage to
the 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 rneasur­ing circuits, NOT as safety earth ground conncctionfi.

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 on the test fixture, connect it to safety earth
ground using #18 AWG or larger wire.

The

$

symbol on an instrument or accessory indicates that 1OOOV or
more may be present on the terminals. Refer to the product manual for de­tailed operating information.

Instrumentation and accessories should not be connected to humans.
Maintenance should be performed by qualified service personnel. Before

performing any maintenance, disconncct the line cord and all test cables.

SPECIFICATIONS

CHANNELS PER CARD: 10.
CONTACT CONFIGURATION: Z-pole Form A with

user selectable shield or driven guard. Each pole is
fused using No. 38 AWG magnet wire.

CONNECTOR TYPE: Screw terminals, No. 16 AWG

maximum.
RELAY DRIVE CURRENT: 57mA per relay typical.
MAXIMUM SIGNAL LEVEL: 1lOOV peak, 0.5A nns

switched, 1 .OA rms carry, 1OVA (resistive load only).
CONTACT LIFE: >lO”closures (cold switching); >5 x 10‘

closures (at maximum signal levels).
CONTACT RESISTANCE: <2WmQ initial, 2n to rated

life.
CONTACT POTENTIAL: <35pV per contact pair with

copper leads.
ACTUATION TIME <2ms, exclusive of mainframe.
CHANNEL ISOLATION: >lO’“fl, <lOpF.
INPUT ISOLATION:

Differential: >lOQ, c50pF.

Common Mode: >lOQ <150pF.
COMMON MODE VOLTAGE: 1lOOV peak.

OPERATING ENVIRONMENT: 0’ to 50°C; up to 35°C

at 70% R.H.
STORAGE ENVIRONMENT: -25O to +65OC.

DIMENSIONS, WEIGHT: 32mm high x 114mm wide x

272mm long (l-l/4 in. x 4-l/2 in. X lo-3/4 in.). Net

weight 0.34kg (12 oz.).

TABLE OF CONTENTS

SECTION 1 - General Information

1.1

Introduction. .........................

1.2

Warranty Information .................

1.3

Manual Addenda

.....................

1.4

Safety Symbols and Terms ............

1.5

Unpacking and Inspection .............

1.6

Specifications ........................

.......

.......

.......

.......

.......

.......

.:

2
3
3
3

SECTION 2 - Operation

2.1

Introduction ..........................................

5

2.2

Safety Precautions

....................................

5

2.3

Wiring ...............................................

5

2.4

Installation and Removal

.............................. 6

2.5

Operating Considerations

............................. 7

2.6

Applications

.........................................

11

2.6.1

Shielded

..........................................

11

2.6.2

Guarded.. ........................................ 12

2.6.3

Driven Guard ..................................... 12

2.6.4

4-Wire .............................................

13

SECTION 3 - Servicing Information

3.1

Introduction

.........................................

17

3.2

Handling and Cleaning

.............................. 17

3.3

Recommended Test Equipment,

.......................

18

3.4

Contact Resistance Test

...............................

18

3.5

Isolation Tests

.......................................

19

3.5.1

Channel Isolation

..................................

20

3.5.2

Input Isolation.,

...................................

22

SECTION 4 - Replaceable Parts

4.1

4.2

4.3

4.4

4.5

Introduction...............,,,...........,,..........

Replaceable Parts
Ordering Information 25

Factory Service .,. 25
Component Layout and Schematic Dmgram., 26

ii

LIST OF TABLES

SECTION 3 - Servicing Information
3-l

Recommended Test Equipment. 18

SECTION 4 - Replaceable Parts
4-1

Model 7l54 Replaceable Parts 26

iii/iv

LIST OF ILLUSTRATIONS

SECTION 1 - General Information
l-1 Model 7l54 Simplified Schematic. 1

SECTION 2 - Operation
2-l

2-2
2-3
2-4
2-5
2-6

Limiting Capacitive Reaction Current

.................

Limiting Inductive Reaction Voltage.

..................

Shielded Floating Measurement

......................

Guarded Floating Measurement.

.....................

Single-Pole Switch with Switched Guard

.............

Source with External Sense or Kelvin Measurement

...

9

1’10

11
12

.l3

15

SECTION 3 - Servicing Information
3-l

Contact Resistance

...................................

19

3-2 Channel Isolation

....................................

21

3-3

Input Isolation

...................................... 23

SECTION 4 - Replaceable Parts
4-l

Model 7154 Component Layout 27

4-2 Model 7l54 Schematic Diagram 29

SECTION 1

General Information

1.1 INTRODUCTION

The Model 7154 is a 2.pole high voltage scanner card that switches signal
levels up to llOOV, 0.5A or IOVA peak (lOmA at 1OOOV) for resistive loads

only. Each of the 10 channels on the card consists of a double-pole, nor­mally open (Z-Form A) relay with a user selectable shield or driven
guard connection and a fused input. The output connection and the
input connections have screw terminals with a maximum allowable wire
size of No. 16 AWG. A schematic representation is shown in Figure 1-l.

”

CH. t

I.

Figure l-l. Model 7154 Simplified Schematic

1

Switching is done in less than Zmsec exclusive of the mainframe, and
the specified contact life is >lO’ closures with cold switching and >lO*
closures at maximum signal levels. The relay drive current is 57mAirelay.

The Model i’l54 is field installable in an appropriate Keithley scanner

mainframe (e.g. Model 705 or Model 706). With the isolation between

each channel being greater than 1OYl and less than lOpF, each chan-

nel is well insulated from cross channel noise and interference.

1.2 WARRANTY INFORMATION

Warranty information is stated on the inside front cover of this manual.

If there is a need for service, contact the Keithley representative or
authorized repair facility in your area. Check the back cover for ad­dresses. The service form supplied at the end of the manual should

be used to provide the service facility with information concerning any
difficulty.

1.3 MANUAL ADDENDA

Product improvements or changes to this manual will be explained on
an addendum included with the manual. It is recommended that this
information be incorporated immediately into the appropriate places

in the manual.

If an additional instruction manual is required, order the manual
package (Keithley Part Number 7154-901-00). The manual package in-

cludes an instruction manual and all pertinent addenda.

2