Fluke 540B - Page 14

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540B

REF

NAME

REF

FUNCTION

NR. DESIG

1

PERCENT

INPUT M

10

1

Search

circuit

indicator

which

reads

% of

input/range

sele

cted. Indicates

battery

condition,

which

is

adequat

e

when the

me

t

er

reads

above

the

lower

lim

it

of

the

BAT

band on t he

meter

scale.

Indicates

that

the

protection

c

ircuit

h

as

operated

and

needs

resetting,

when

the

needle

is

in

the

OVER

LOAD

area.

Does not function

in

current

sh

unt op

eration.

2 GALVANOMETER M 102

Th

e

null

indica

ting device

us

ed

to

determine

the

balance

between the

variable

reference

voltage

and

the

thermo-

coup

le

output.

3 POWER

s 101 Applies

battery

power

to

the

instrument

in

the

ON

position.

Wh

en in

the

BATTERY CHECK; REFERENCE, GALV

or

SEARCH

position

s

the

PERCE

NT

INPUT

meter

will

indi-

cat

e

the

condition of

each

set

of

batteries.

4 SENSITIVITY s 105

U

sed

to

select

the

range

of

galvanometer

sensitivity;

LOW, MED and HIGH.

5 GALV ZERO

R4

The

elect

rical

zero

adjustment

for

the

galvanometer.

6

HIGH

FREQ

CONVERTER J 102 Used

to

at

tach

an

external

high

frequency

converter,

such

as

th

e

Fluke

Model A55

Thermal

Converters,

to

the

in-

stru

m

ent

. May

also

be

used

to

connect

an

external

galva-

nomete

r.

When not

in

use

the

three-pron

g

captive

plug

P 101,

must

be plugged in.

7 GALV s 104

Ele

c

trically

connects

the

galvanometer

circuit

between

th

e

th

e

rmocouple

output and

the

variable

internal

reference

wh

en in

the

LOCK

or

MOMENTARY

positions.

The GALV

sw

itc

h

is

b

riefly

pushed

from

OPEN to MOMENTARY

to

d

ete

rmine

if

the

galvanometer

will

indicate

on

scale

with-

ou

t f

urther

adjustment.

After

an

on

scale

indication

is

obtain

ed,

the

GAL V

switch

may

be

set

to

LOCK.

8 SENSITIVITY

TEST

s 102 Used

to

determine

the

amount of

deflecti

on of

the

galva

-

nometer

for

0.

1%

and

0.

01%

changes

in

input.

9 REFERENCE ADJUST s 103 The COARSE, MEDIUM

and

FINE

controls

vary

the

refer-

R 405 ence v

ol

tage

for

galvanometer

balance.

R408

10 MODE s 801 Selects SEARCH

or

TRANSFER modes

for

either

AC

or

DC

input

to

the

instrument.

Range

selection

is

made

in

th

e SEA

RCH

modes by

selecting

a voltage

range

that

gives

a PERCENT INPUT

meter

indication between

50%

and

100

%.

The

TRANSFER

positions

connect

the

selected

range

to

the th

ermocouple

.

Transfers

may

be

made

at

inputs

below

50%

but

sensitivity

will

diminish.

Should

an

over-

load

occur,

the

Model 540B

may

be

reset

by switching

the

mode

switch

to

OFF

and then back

to

the

desired

mode.

11

RANGE

s 501 S

elects

the

proper

dropping

resistor

and

compensating

netwo

rk

for

measurements

of

voltages

up

to

and

including

th

e vo

ltage

indicated (de

or

ac

rms

). The SHUNT

position

is

us

ed

w

ith

Fluke Model A40

Current

Shunts.

12

POLARITY

s 802

Is

u

se

d

to

re

v

erse

the

input

to

the

thermocouple

to

facili-

tat

e t he

measurement

of

the

turn-over

error

of

the

thermo-

coup

le

.

Figure 2-2.

FRONT

-PANEL CONTROLS,

TERMINALS,

AND

INDICATORS

(Sheet 1 of 2)

2-2

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