Solartron 7091 Operating Manual

7061

SYSTEMS

VOLTMETER

OPERATING

MANUAL

'ssueC:

Nov

1986

Part

No.

70610012

Solartron

Instruments,

Victoria

Road,

Farnborough

Hampshire,

England

GU

14

7PW

Telephone:

Farnborough

(0252)

544433

Telex:

858245

Solfar

G

Cables:

Solartron

Farnborough

solartron

pursues

a

poi'cy

of continuous

development

and

product

improvement

he

specification

m

this document

may therefore

be

changed

without

notice

19©86

Contents

Chapter

1

General

Information

Page

1.1

l

Introduction

1.2

2

Accessories

1.2

3

The

Configuration

Switch

1.3

4

Options

1.4

5

Safety

1.5

6

Connecting

the

ac

mains

1.6

Chapter

2

Getting

Started

2.1

Chapter

3

Front

Panel

Controls

3.1

1

Introduction

3.3

2

Front/rear

switching

3.6

3

Measurement

keys

3.7

4

Range

keys

3.7

5

Filter

key

3.8

6

Null

key

3.8

7

Ratio

key

3.8

8

Channel

key

3.9

9

Digits

key

3.10

10

Track

and

trigger

keys

3.10

11

General

operating

keys

3.13

12

Interface

keys

3.13

13

Reset

+

enter

&

Menu

+

reset

keys

3.14

14

Timer

key

3.15

15

Scan

key

3.17

16

Delay

key

3.18

17

Probe

key

3.18

18

Progs

key

3.20

19

History

key

3.28

Chapter

4

Connections

&

Measurements

4.1

1

General

4.2

2

Voltage

4.2

3

Current

4.3

4

Resistance

4.3

5

Drift

correction

4.4

BRS/7061/2

Chapter

5

Remote

Control

5.1

1

Introduction

5.3

2

Remote

commands

and

program

names

5.4

3

Interface

command

language

5.6

4 Command

set-

verbose

5.6

5 Command

set

-

cryptic

5.37

6

Programs

5.40

7

Error

messages

5.45

8

Using

the

7061

from the

GPIB

5.46

9

GPIB functions

5.54

Chapter

6

Interference

-

some

causes

and

cures

6.1

1

Introduction

6.2

2

Series mode

interference

6.3

3

Remedial

action

6.3

Chapter?

Specification

7.1

Chapter

8

Calibration

8.1

Appendix

A

Adopted

settings

on

power-up

&

reset

Appendix

B

Measurement

delay

&

integration

times

Appendix

C

Overload

indication;

display

&

output

formats

Index

BRS/7061/3

[Chap.

1

1

Chapter

1

General

Information

Para.

Pa

8

e

1

Introduction

1-2

2

Accessories

1-2

3

The

Configuration

Switch

1-3

4

Options

1-4

4.1

Scanner

option

1-4

4.2

Memory

option

1-4

5

Safety

1-5

5.1

General

Safety

Precautions

1-5

5.2

Earthing

1-5

6

Connecting

the

ac

mains

1-6

6.1

Voltage

Selector

1-6

6.2

Mains

Fuses

1-7

6.3

Mains

Lead

1-7

6.4

Connection

Procedure

1-8

BRS/7061/2

1.1

[Chap.

1|

INTRODUCTION

The

7061

combines high

speed digital

electronics with

microprocessor

control

to

provide

a

fast,

accurate

systems

voltmeter. With

channel

scanning,

timer

control

and

measurement

processing,

the 7061 is

ideally

suited

to

automated

test

requirements

using

the built-in

IEEE

488

interface (GPIB)

to

give

remote

control.

The

7061 is

equally at

home

as a bench

instrument,

with

scanning,

timing

and

processing

facilities

all controllable

from

the front panel.

And,

of course,

straightforward

voltage,

current

and

resistance

measurements are

easily

made

with

great

reliability

and

accuracy.

Chapter 1

of the

manual

deals with

details

relevant

to the

installation

of

the

voltmeter.

Rack

mounting

is dealt with

in

Appendix D.

To

make

simple

measurements, refer

to Chapter

2,

'Getting

Started'.

For

more

advanced

measurements using

processing

facilities,

but still

under

front

panel

control,

refer to

Chapter

3,

'Front

Panel Controls'.

To

use the

7061

as

a

remotely

controlled

instrument

via

the

GPIB,

refer

to

Chapter

5,

'Remote

Control'.

For

information

on making

measurements,

see

Chapter

4.

Chapter

6 contains

the full

specification and

chapter

7

gives

calibration

information.

ACCESSORIES

Supplied:

2-terminal

input

lead

Power

lead

Copper

crocodile clip

(2)

Rack

mounting

brackets

(2)

Operating

manual

2-terminal

reference

lead

Spare

fuses

Calibration

key

Optional:

High

voltage

probe

70757

2-

terminal

input

lead

3187

3-

terminal

input

lead

3193

5-terminal

input

lead

3183

Kelvin

input

lead

(4-terminal

ohms)

70758

E

Low

thermal

input

lead

kit

70758 D

2-terminal

reference lead

70617

B

4-

terminal

reference

lead

70617

D

Temperature

probe, insertion

PRT 70617 E

Telescopic

rack

slides

(pair)

70759

Technical

manual

70610011

1.2

BRS/7061/2

[Chap.

1|

3

THE

CONFIGURATION

SWITCH

The

configuration

switch is

a

dual

in-line

switch

inside

the

instrument.

Its

settings are

shown

in

Fig.

1.1,

with

the

example

showing

50

Hz

line

frequency

and

8

channel

operation

selected.

(5)

SPARE

(4)

SPARE

(3)

16/8

CHANNEL

(2)

SPARE

(1)

LINE

FREQUENCY..

(0)

LINE

FREQUENCY..

1

—

I

nn

i m

t=m

M“=I

i=*i

50

Hz

400

Hz

60

Hz

50

Hz

Fig.

1.1

Configuration

switch

settings

To

reach

the

switch,

disconnect

the

instrument

from

signal

inputs

and

from

the

mams

supply

before

removing

the

top

panel.

This

is

held

in

place

by

four

screws.

The

switch is

just

behind

the

front

panel,

to

the

left

of

centre,

as

shown

in

Fig.

1.2.

If the

memory

expansion

board

is

Fitted,

this

will

have

to

be

removed

in

order

to

reach

the

switch.

It

is

held

in

place

by

three

screws.

Fig.

1 .2

Plan

view

showing

position

of

configuration

switch

BRS/7061/2

1.3

[Chap.

1]

4

OPTIONS

4.1

70612A

SCANNER

OPTION

The scanner option

increases

the

number

of physical input

connectors

on

the

instrument

from

2

to 10

(plus

current input). There are then

8,

4-pole or

16,

2-pole

extra

channels

available, depending

on

the selection

made

using

the

configuration

switch.

1)

HI

ohms source

2)

LO

3)

LO

ohms source

4)

HI

5)

Not

used

Fig.

1.3 Rear

panel view

of

connector

socket,

8

channels

selected

1)

HI

(channels

10-»

17)

2)

LO

(channels

2-*

9)

3)

LO

(channels 10

17)

4)

HI (channels

2

-»

9)

5)

Not

used

Fig.

1.4

Rear

panel

view

of

connector

socket, 16

channels

selected

Input

plug

:

SwitchcraftTA5FL

(Solartron no.

351505030)

More

details are given in

the

sections on the CHANNEL

and

SCAN

keys

and the

CHannel and

SCan

commands.

4.2

70613A MEMORY

EXPANSION

OPTION

The

memory

expansion option increases

the

measurement

buffer from

1000

to 8000

memory

locations.

1.4

BRS/7061/2

[Chap.

1

1

5

SAFETY

The

7061

has been

designed

in

accordance

with

the

IEC

publication 348

(Class

1),

'Safety

Requirement

for

Electronic

Measurement

Apparatus',

and has

been

supplied

in

a

safe

condition.

This operating

manual

contains

information

and

warnings

which must be

followed

in

order

to

ensure

safe

operation

and

to

keep

the

equipment

in a

safe

condition.

The

operating

instructions

include

safety

precautions

where

appropriate,

but

the

principal ones

are

also

listed

below.

5.1

GENERAL

SAFETY

PRECAUTIONS

1.

Before

switching on,

ensure

that

the

mains

lead

is

connected

to

the

ac

supply

in

accordance

with the colour

code.

2.

Ensure that

the

mains

voltage

selector

is

correctly

set.

3.

Ensure that the

mains

plug

is

connected

only to a

mains

outlet

which has a

protective

earth

contact.

This

applies

equally

if an

extension

lead

is

used:

the

lead

must

contain an

earth

conductor.

4.

For

earthing, the

mains

plug

must

be

inserted

before

connections

are

made

to

measuring

and

control

circuits.

The

mains

plug

or

external

earth (as

appropriate)

must

remain connected

until

all

measuring

and

control

circuits

have been

disconnected.

5.

Any

interruption of

the

earth

connection

(inside

or

outside

the 7061)

is

prohibited.

6.

When

the

7061 is

connected to

its

supply

the

opening of

covers or

removal of

parts

couid expose

live

conductors.

The

7061

should be

disconnected

from

all voltage

sources

before it

is

opened

for

any

adjustment,

replacement,

maintenance

or

repair.

Adjustments,

maintenance

or

repair

of

the

7061

when

it is

powered

should

not be

attempted.

Consult

a

Solartron

Service

Centre

if

repairs are

necessary.

7.

Ensure

that fuses

of

the correct

rating

and

of-the

specified

type

are

Fitted.

Makeshift

fuses,

and

short-circuiting

of fuse

holders,

is

prohibited.

8.

Whenever

it

is

likely

that the

safety

of

the

7061

has been

impaired, it

should be

switched

off and not

used

again

until

repaired.

Safety

could be

impaired

if the

7061:

a.

shows

visible

damage

b.

fails to

perform

intended

measurements

c.

has been

subjected

to

prolonged

storage

under

unfavourable

conditions

d.

has been

subjected

to

severe

transport

stress.

9.

The

'A' and

T

symbols

on

the

7061

mean

'Refer

to

Operating

Manual'

for detailed

instructions

or

safety

precautions.

5.2

EARTHING

For safety,

an

earth

connection

is

essential

whenever

measurement

and

control circuits

are

connected,

even

if the

7061

is

switched

off.

The

instrument

is

earthed

by

connecting

it

to

a

mains

outlet

or

other

suitable

earthing

point.

This

earth

should

be

capable

of

carrying

25

A and

conform

to

the

regulation

in

'British

Standard

Code

of Practice

CP

10

13

1965,

Earthing'.

BRS/7061/2

1.5

(Chap.

1|

CONNECTING

THE

AC

MAINS

lever

flap

open

from here

The

7061

is

fitted with

a

mains

unit

(Fig.

1.5)

containing

two mains

fuses,

and a

voltage

selector.

These items

cannot

be accessed

until

the mains connector has

been unplugged

from

the unit.

VOLTAGE SELECTOR

The

following table

gives the correct selector

setting for

different

mains

voltage ranges

(nominal 50Hz or 60Hz):

Mains Voltage

Variation

Range

90-110V

108-

132V

198

-242V

216

-264V

Voltage

Selector

Setting

Required

100V

120V

220V

240

V

In

cases

of doubt,

set

the voltage

selector to

the

lower

of the two possible

values

to ensure

that all

7061 internal

voltage levels

are

fully

attained.

To change the

selected

voltage:

1. Unplug

the

mains connector

from

the

unit.

1.6

BRS/7061/2

[Chap.

1]

2.

Lever

open

the

hinged flap

with

a

screwdriver

and

lift

out

the

voltage

selector roller

block.

3.

Refit

the

block

with the

chosen

voltage

value

facing

outwards.

4.

Close

the

flap

securely,

checking

that

the

correct

value shows

through

the

aperture.

5.

Plug

in the

mains

connector

again.

6.2

MAINS

FUSES

Live

and

Neutral

are

both

fused

in the

7061.

Fig.

1.5

shows

how

these

fuses

are

accessed,

after

the

mains

connector

has

been

unplugged.

The

arrowheads

marked

on each

fuseholder

must

align

with those

on

the

flap

when

the

fuesholders

are

refitted.

The fuse

values

are:

200 mA,

SLO-BLO

for

220V

or

240V operation

400 mA,

SLO-BLO

for

100V to

120V operation

Relacement

fuses

must be

20mm

x

5mm

cartridge type.

6.3

MAINS

LEAD

An

appropriate

ac

mains

connector

lead,

complete

with a

mating

socket

for

the

IEC plug

on the

7061

mains

input

unit,

is

supplied

according

to the

destination

country.

This lead

should be

connected

to the

ac

supply

according

to

the

following

colour

code:

BROWN

=

LIVE

BLUE

=

NEUTRAL

GREEN/YELLOW

=

EARTH

An IEC

socket

and

lead

other

than

the

one

supplied

may

be

used,

but

it

must be

correctly

wired as

shown in

Fig

1.6.

Fig.

1.6

IEC

power

socket

connections

BRS/7061/2

1.7

I

Chap.

II

CONNECTION

PROCEDURE

1.

Before connecting the

supply, ensure

that

the

mains voltage selector on the rear

panel

is

correctly

set,

and

that the

correct fuses are fitted

in

the

mains

input

unit.

If

necessary,

the mains power frequency

selection

can

be checked

by

looking

at the

configuration switch

(see

para.

3).

2.

Ensure that

the power-

on/off

switch on

the

rear panel,

next

to

the

mains

input

unit,

is

'off.

3. Connect the mains

lead.

4.

Switch

the

7061

'on' at the rear

panel.

1.8

BRS/7061/2

I

Chap.

2|

Chapter

2

Getting

Started

Getting

Started

Page

2.2

BRS/7061/2

2.1

[Chap.

2

1

GETTING

STARTED

At first sight,

the

front

panel may

appear

to be rather

complex,

but to make

simple

measurements of voltage,

current and resistance,

only

a

few of

the

keys

are

required.

These are some

of the

keys

to

the right

of the display and the

two

orange

keys

near the

bottom

left

hand

corner

of

the

display.

After

plugging

in

to

the

mains supply, connect

a

two-terminal test

lead to

the

input

socket and switch on the

machine (rear panel mains switch).

DC

VOLTAGE

To

measure

dc

voltage, connect the test

leads to the voltage

source and

make

the

following sequence of

key

pushes,

using the keys shaded

black

on the diagram

:

2.2 BRS/7061/2

[Chap.

2|

AC

VOLTAGE

To

measure ac

voltage,

the

keys

used

and

the

sequence

of key

pushes

are

as

follows

:

TRACK

s /

t

Press

if TRACK

LED

not lit.

Notice that

in

both

of the

above

measurements,

AUTORANGE

and

TRACK

were

used.

Using

AUTORANGE means that

there

is

no

need

to worry

about

selecting

the

correct

range to

match the

level

of the

input

signal

-

this is done

automatically.

TRACK

gives

a

continuous sequence

of

readings, so

the

display is continually

being

updated.

To

get

a

single

measurement, press

TRIG

instead

of

TRACK

and

the

single

reading

remains in the

display

until another

one

is made.

DC CURRENT

To make

a

single

reading of

dc

current,

connect the

current

source to

the

two

4mm input

sockets on the

rear panel

and make the

following key pushes

:

BRS/7061/2

2.3

[Chap.

21

RESISTANCE

Measuring

resistance

is

just as

easy.

Connect

the

two

terminal

test

lead

across

the

unknown

resistance

then

:

The

more

straightforward

measurements

have

now

been

described, but note

that there

is

a

key

labelled

'True

Q'.

This

may

be

used

instead of

Q

when thermally

induced

voltages

and

currents could be a

problem,

for

example,

when

measuring

low resistances

in relay

circuits.

There

are

other keys,

'NULL'

and

'FILTER',

which also

allow more

accurate

measurements

under

certain

circumstances.

See

the

chapter

on 'Front

Panel

Controls'

for details

of

their

use.

The

same

chapter

describes

the

functions of

all

the

remaining

keys.

Use

of

these allows

great

flexibility

of

measurement

and

processing of

results.

Some of

the

front

panel

keys

call

up

menus.

In

other words,

on

pressing the

key,

a

choice

of

functions

is

given. Menu

keys

are

shown

shaded

in the

following diagram:

r

f=

2

7061

SYSTEMS

VOLTMETER

1.234567

KOHM

“1

'

J

nj

]iii

i

v

one

oo

J

As an

example, the

darker

shaded

key,

the

RATIO

key,

allows the

multiplication or

division of the

measured

value

from

any

channel by

the

value

from any other

channel.

2.4

BRS/7061/2

[Chap.

2|

RATIO

A possible

application

for

RATIO is

the

direct measurement

of power,

for

example, dc

power:

Connect

the current

source to

the

4mm

rear

panel input sockets

(channel 0 current

input). Connect

the reference

lead

(channel

1)

so as to

measure

voltage across the

relevant component. Then

Select

channel 0

:

Set

up channel

0 to

read dc

current

:

Press

either

skip key

until

'RATIO

CHAN

=

shows

in the

display.

Set

channel

1 to

read

dc

voltage,

autorange

:

Go

back

to

channel

0:

BRS/7061/3

2.5

fChap.

2

1

Now set

the

ratio

function

to

give

the

product of

channel

0 with

channel

l

:

Press

either

skip key

until

'PRODUCT'

shows

in the

display.

(Note

that

the

vertical

arrows

to

the

right of the

display

mean

that

'SKIP'

(

T i

)

then

'ENTER'

are

the

next keys to

be

pressed.)

The

display

now

shows the

product

of

the two

channels

-

in

this case,

a

direct

reading

of

power.

The

'PRD'

in the

display

indicates

a

product

reading.

SCANNING

The

usefulness

of

the

instrument

is

increased

by its

ability

to

measure

more

than

one

channel

on

receipt

of

a

trigger.

This is

achieved

using

the scan

key.

Details are

described

later

in

the

manual,

but

a

simple

scan sequence

using

channels

0

and

1 is

shown here.

First

initialise the

instrument,

then

turn

track

off

:

then

’7061

INITIALISED’

2.6

BRS/7061/2

[Chap.

2

1

Ensure that the GPIB

is set

to

OUTPUT

OFF

using the

following

key sequence

Press

either

skip

key

until

'GPIB'

shows in

the

display.

Then:

t

L A

r

-

i

ENTER

< >

ENTER

k

1

r

1

'

'

^

1

v J

Press either skip key

The

last

part

of the menu

until

'OUTPUT

OFF

'

shows

is

irrelevant

to

front panel operation

in the display.

-

simply

press

ENTER

again

Suppose

we

want

to measure

ohms both

on the

main

input

(channel

0),

and on

reference

input (channel

1).

Set up

channel

0 to read

ohms

:

Select

channel l and set

it

to read

ohms

:

BRS/7061/2

2.7

[Chap.

2]

Set

up the

scan

sequence

from

channel

0 to

channel

1

:

The

display

now reads

*

CHANNEL

=

0

This

is

the

default

setting,

which in

this

case

is

wanted.

’ENTER'

the

default

setting,

then

put

channel

1 into the

scan

sequence

:

’

CHANNEL

=

END

'

’

CHANNEL

=

END

'

The scan

sequence

has

now

been

set

up,

and

it

starts

each

time

a

trigger

is

sent or

runs

continuously

when

TRACK

is

on.

The

display

shows

first

the

reading

from

channel

0,

then

the

reading

from

channel

1.

Before

preceding

to the

next

example,

turn

off the

scan

sequence

by

pressing

SCAN:

PROGRAMS

The

7061

contains

seven

programs

for

processing

data.

They

are

described

in

detail

in

chapter

3

(Front

panel

controls)

and chapter

5

(Remote

control).

For

example,

the

OFFSET

program

adds

a

pre-defined

constant

to

the

measured

value.

For

instance,

add

10 to

each

measurement

:

2.8

BRS/7061/3

[Chap.

2]

Select

the

OFFSET program

:

Press either skip key

until 'SELECT' shows in

the

display.

[Note

: The skip

keys

will

appear

when programs

have

been selected

previously.]

Then:

until

'OFFSET ' shows

in the display.

Set the offset

constant

to

10

:

The

display briefly

reads 'READY' and then 'SELECT'.

This

allows

the option

of

selecting more programs.

If

no further programs

are required, simply

press the

MENU

key:

The program

is

now

'on'

so

that any

readings

made

have the value

10 added to them. (To turn programs

off,

press the PROGS key,

and

the

LED

goes out.)

BRS/7061/3

2.9

[Chap.

2]

PREPARATION

FOR

REMOTE

CONTROL

Many

of

the

simpler

front

panel

measurements

have

now

been

described.

Another

important

function

of

the

front

panel

controls

is to

set

up the

GPIB

output to

prepare the

instrument

for

remote

control.

For

example,

to

set

the

output

’on’

and the

GPIB address

to

'12',

use

the

following

key

sequence

:

Press

either

skip

key

until

’GPIB*

shows in

the

display.

Set

GPIB

output

to

’on’

until

’OUTPUT

ON

’

shows

in

the

display.

Set

GPIB

address

to

12

(for

example)

Press

either

skip

key

until

'ADDRESS

=

--

'

shows

in the

display.

The

instrument

is

now ready

for remote

control.

See

chapter 5

for

details.

2.10

BRS/7061/2

[Chap.

31

Chapter

3

Front

Panel

Controls

Para.

Page

1 Introduction

3.3

1.1

Menus

3.3

1.2

Measurement

handling

3.3

1.3 Overload indication

3.5

2

Front/Rear

switching

3.6

3 Measurement

keys

3.7

4

Range keys 3.7

5 Filter

key

3.8

6

Null key

3.8

7 Ratio key

3.8

8 Channel key

3.9

9

Digits

key

3.10

10

Track and

trigger

keys

3.10

10.1

Track key

3.10

10.2 Trigger

key

3.11

10.3

Trigger operation

3.12

11 General operating

keys

3.13

12

Interface key

3.13

13

Reset

+ Enter

&

Menu +

Reset

keys

3.14

14

Timer key

3.15

15 Scan key

3.17

16

Delay key

3.18

17

Probe

key

3.18

Continued

overleaf

BRS/7061/2

3.1

[Chap.

31

Para.

Pa

S

e

18

Progs

key

3.20

18.1

Programs

3.21

18.1.1

^deviation

3.21

18.1.2

Divide

3.22

18.1.3

Limits

3.23

18.1.4

Maxmin

3.24

18.1.5

Offset

3.25

18.1.6

Scale

3.25

18.1.7

Statistics

3.26

18.2

Program

examples

3.27

19

History

key

3.28

Alphabetical

list

of

keys

Page

AC

3.7

AUTORANGE

3.7

CHAN

3.9

CLEAR

3.13

CURRENT

3.7

DC

3.7

DELAY

3.18

DIGITS

3.10

ENTER

3.13,14

FILTER

3.8

HISTORY

3.28

LOCAL

3.12

MEM

3.12

MENU

3.12

NULL

3.8

OHMS

3.7

PROBE

3.18

PROGS

3.20

RATIO

3.8

RESET

3.14

SCAN

3.17

SRQ

3.13

TIMER

3.15

TRACK

3.10

TRIGGER

3.11,12

TRUEQ

3.7

VOLTAGE

3.7

t

|

3.7,13-

3.2

BRS/7061/2

[Chap.

3]

1

INTRODUCTION

This

chapter describes

the

functions

of the

front panel

keys

in

some detail.

Some keys

call up menus

to

give

choices

in

the use

of functions.

To make

straightforward

measurements of voltage, current and resistance, much

of

this

information

is not

needed.

Chapter

2

provides

a

simple

introduction

to

such

measurements.

When

an

LED

in

a

key

is

lit,

it

indicates

that the

associated

function

is operating.

When an LED

is flashing, it indicates that the associated

menu has

been called

up.

The instrument

may be Initialised* either

to

clear existing

settings

or

to

get out of

any

problem,

or uncertain condition. The instrument then

has the

settings shown

in

Appendix A.

Initialise

by

pressing

the RESET key then the

ENTER

key.

LI

MENUS

Menu items are

shown

on the display and

read

through

with

the

aid

of the

skip

(

|

or

i

)

keys.

Then

selected items

are implemented using

’ENTER*.

When

numbers have

to

be

entered

in

menus,

the

second level

numeric

keypad

is used.

In

the descriptions of

keys which

invoke

menus, diagrams

are

used.

Dotted

boxes show

information

that can

be displayed. Solid

boxes

and arrows

show

examples of

typical

routes

through the menus. The

sequences of key-pushes are

numbered. Fig.

3.1 shows the

delay

key

as a

simple

example

of

a

menu.

When

all the

selections for

a

menu

function

have been done, and

the final ENTER

key-

push has

been made,

the MENU LED goes out but the function

LED

stays

on,

indicating

that

the function is

now

operative.

The setting

up

of

a

menu

function can be abandoned at any time

by pressing either

the

MENU

or the function

key.

Anything

keyed

in

since the previous

pressing of

the

ENTER

key is then ignored.

(D

(2)

(3)

DELAY

USER

—

7

8

9

4

5 6

"7

2

3

0

./E

+

ifT“

ENTER

J

Fig.

3.1 Example menu

1.2

MEASUREMENT

HANDLING

The

7061 can measure voltage, current and

resistance as

well

as

’True ohms’, the

latter

being

a

resistance

measurement

which

compensates for

thermally

induced voltages.

The

power

of

the instrument

is

greatly

enhanced

by

the

use of signal

processing

using

data

storage,

probe processing

and programs.

Extra

input channels

may be added by fitting

the

scanner

option

(70612)

or more complex processing may

be achieved

by using

’virtual*

channels. These are

described

in the

sections on

the

CHANNEL

key

and

the

CHannel

command.

BRS/7061/2

3.3

[Chap.

31

Figures

3.2

and

3.3

are

block

diagrams

showing

possible

paths

of

a

measured

value

through

the

instrument.

'History

File

access'

is

the

output,

or

processing

then

output, of

results

stored

in

the

measurement

buffer.

This

is

done

remotely

using

the DUmp

command

or

from

the

front

panel

using

the

History

key.

Probe

and

program

processing

may be

switched

in

or

out

of

any

channel

and the

kind of

processing

may

be

set

up

independently

for

each

channel

or

virtual

channel.

Display

GPIB

Probe

and

program

processing

OFF

Display

GPIB

Probe

and/or

program

processing

ON

Fig.3.2

MEASUREMENT

Post-processing

disabled

or

Post-processing

enabled

and.

Probe

and

Program

processing

OFF.

Post-processing

enabled

and

Probe

and/or

Program

processing

ON

Fig.3.3

HISTORY

FILE

ACCESS

Caution

for

History

File

accessing:

If the

original

measurement

was

made

with

programs

on,

the

memory

buffer

contains

processed

results.

History

file

accessing

with

programs

on

would

then

give

twice-

processed

results.

(Probe

processing

can

only

be

done

either

during

measurement

or

during

History

File

accessing.

The

instrument

prevents

double

probe

processing.)

3.4

BRS/7061/2

[Chap.

3

1

An

advantage

of

post-processing

is

that

measurements

may

be

taken at

the fastest

possible rate,

then

processed

later

using History

file

accessing.

This

allows the

combination of

rapid measurement

with data processing.

L3

OVERLOAD

INDICATION

If an

input is applied

to the

instrument

and it is

too

high

for the selected

range,

the

display

flashes

on and off as a

warning.

Appendix C

shows

the

levels at

which this

occurs.

The

high input

resistance

(see

specification)

is maintained

even

during

overload on

the

0.1,

1,

and 10

volt

ranges.

BRS/7061/2

3.5

[Chap.

31

FRONT-REAR

SWITCHING

Input

terminals

are

provided

on

both

front

and

rear

panels

except

for

current

measurement

which

is

done

from

the

rear

panel

only.

This

allows

for

both

rack

mounted

or

free

standing

use.

Front

or

rear

inputs

may

be

selected

by

the

front

panel

switch.

A,

FRONT

Push

button

out:

front

inputs

selected.

INPUT

JB.

REAR

Push

button

in:

rear

inputs

selected.

Selection

between

front

and

rear

inputs

cannot

be

done

by

remote

control.

A remote

controller

can

interrogate

the

instrument

(using

the

OPtion

command)

to

determine

which

inputs

are

selected.

FRONT

PANEL

REAR

PANEL

Fig

3.4

Switching

of

front-rear

inputs

3.6

BRS/7061/2

IChap. 3|

3

MEASUREMENT

KEYS

V

L J

/

\

^ >

<

V

l -J

r

1

V

k

>

t

\

I

L J

r

^

k >

r

1

I

r

^

V

^ J

<

Q

.

True

fl

<

>

Voltage,

dc,

0.1V

to

1000V

in 5

ranges.

Voltage,

ac,

0.1V to

1000V

in 5

ranges.

Current,

dc,

1A

in

1

range.

(Rear

panel

only)

Current,

ac,

1A

in

1

range.

(Rear

panel

only)

Resistance,

0.10

to

lOOOkO

and

10MQ,

in

6

ranges.

(10MQ

range

does

2-terminal

measurement

only. See

chapter

4

for

further

measurement

information.)

Resistance,

0.10 to

lOOOkQ

in 5

ranges.

*

*Note,

True

ohm

measurements

are

used

to

compensate

for

thermally

induced

voltages

other

than

those

produced

by

the

measurement

current,

(which

are

removable

by

nulling).

The

instrument

measures

resistance

with

its

source

current

off

then

on.

Subtraction

then

removes

contributions

from

thermal

voltages

and

external

currents.

Settling

times

are

2-3

times

greater

than

for

ohms.

4

RANGE

KEYS

AUTO

RANGE

Selects

or

de-selects

auto-ranging

of

the

chosen

measurement

function.

De-selection

leaves

the

instrument

fixed

in

the

existing

range.

I

Selects

less

sensitive

fixed

range.

Selects

more

sensitive

fixed

range.

The ’up’

and

'down'

skip

keys

also

de-select

autorange.

(When

menus

are

in use,

the

skip

keys

are

used

to

read

through

menu

lists.)

BRS/7061/2

3.7

[Chap.

3]

5

FILTER KEY

Selects

or

de-selects

filtering.

For

ac

measurements, FILTER improves low

frequency

response

and

hence

accuracy.

Use FILTER for

all

ac

measurements

of 400 Hz or

below.

For

dc measurements, FILTER

improves

noise rejection by

increasing

measurement

integration times

fourfold.

The

use

of the filter

increases

both ac and

dc measurement

integration

and

settling

times.

6

NULL KEY

Null

compensates for

small

dc offsets (max. 2%

of Vdc,

1

%

of

Idc,

Ohms

and

TrueOhms

ranges)

at the

point of

measurement. Null

is

not applicable

on

V

ac

and

I

ac

ranges.

NULL

on AUTORANGE

nulls all

ranges. The

same command

on

a fixed

range

nulls

that

range

only.

To

null volts

and ohms,

short input leads;

to null current,

open circuit input

leads. Then

press

NULL. The voltmeter

meaures

the offset

('NULLING’)

and

stores

the

result

('NULL COMPLETE’).

The

stored

offset is then

subtracted automatically from all

subsequent

dc

measurement

values in

that mode and

range.

Channels

0 and 1 can

hold

null

values for all

nullable

modes and

ranges.

Channels 2

to 9 or 2 to

17 can hold nulls

for one

mode

only,

e.g. for all

the

ranges of the Vdc

mode.

When

null is operating, pressing NULL

switches

null off for all

modes and

ranges. These

settings can

then

only

be recovered

via

the interface

'NUll

ON* command.

Null may

be

retained after switching-off,

depending

on

the setting

of

RESUME

which

is

done

via

MENU RESET.

7 RATIO

KEY

Selects (or

de-selects)

either division

or multiplication

of the

presently

selected

channel

by the

value

from

the

ratio channel,

as

selected

under the

CHANNEL

key

menu:

RATIO

^

4

f

NULL

s

/

FILTER

^ -s

3.8

BRS/7061/2