Bruel & kjaer 1526 User manual

Strain Indicator

Type

1526

With

Accessories:

Multipoint Selector and Control

Type

1544

Multipoint Selector

Type

1545

The Type

1526

is a

direct-reading

digital

Strain

Indi-

cator

ideally

suited

to

the

measurement

of

static

strain,

as

well

as

dynamic

strain

up

to

a

frequency

of

300Hz.

It can be used

with

a

wide

range

of

strain

gauges

(and

strain-gauge

transducers)

in

quarter-,

half-,

or

full-bridge

configuration.

Up

to

5

strain-

gauge

bridges

may

be

monitored

.

For

monitoring

up

to

400

bridge

configurations,

the

1

526

can be connected

to

a

Multipoint

Selector

and

Control Type

1544

with

up

to

39

Multipoint

Selec-

tors

Type

1545.

The Type 1

544

also has

an

output

socket

for

the

transfer

of

digital

information

via

the

B & K Interface

Bus

to

other

digital

recorders and pro-

cessors.

Bri.iel

&

Kjcer

1526

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BROEL &

KJ~R

instruments

cover

the

whole

field

of

sound

and

vibration

measurements.

The

main

groups

are

:

ACOUSTICAL

MEASUREMENTS

Condenser

Microphones

Piezoelectric

Microphones

Microphone

Preamplifiers

Hydrophones

Sound

Level

Meters

Precision

Sound

Level

Meters

Impulse

Sound

Level

Meters

Noise Dose

Meters

Noise Level

Analyzers

Stending

Wave

Apparatus

Calibration

Equipment

Reverberation Processors

Sound

Sources

ACOUSTICAL

RESPONSE

TESTING

Sine

Generators

Random Noise

Generators

Sine-Random

,

Generators

Artificial

Voices

Artificial

Ears

Artificial

Mastoids

Hearing

Aid

Test Boxes

Audiometer

Calibrators

Telephone

Measuring

Equipment

Audio

Reproduction Test

Equipment

Tapping

Machines

Turntables

VIBRATION

MEASUREMENTS

Accelerometers

Force

Transducers

Impedance Heads

Accelerometer

Preamplifiers

Vibration

Meters

Accelerometer

Calibrators

Magnetic

Transducers

Capacitive

Transducers

Complex

Modulus

Apparatus

Bump

Recorders

VIBRATION

TESTING

Exciter Controls -

Sine

Exciter

Controls-

Sine-

Random

Exciter Equalizers, Random or Shock

, Exciters

Power

Amplifiers

Programmer

Units

Stroboscopes

STRAIN

MEASUREMENTS

Strain

Gauge

Apparatus

Multipoint

Selectors

MEASUREMENT

AND

ANALYSIS

Voltmeters

Phase

Meters

Deviation Bridges

Measuring

Amplifiers

Band-Pass Filter Sets

Frequency

Analyzers

Real

Time

Analyzers

Heterodyne Filters and

Analyzers

Distortion

Measuring

Equipment

Psophometers

Statistical

Distribution

Analyzers

Tracking

Filters

RECORDING

Level Recorders

Frequency Response

Tracers

Tape Recorders

Alphanumeric

Printers

Digital Event Recorders

DIGITAL

EQUIPMENT

Computers

Tape

Punchers

Tape Readers

BrUel

&

Kjcer

DK-2850 N.ICRUM,

DENMARK

·

TELEPH

.· (

02

) 80

05

00 ·

CABLE

:

BRUKJA

,

COPENHAGEN

·

TELEX

: 15316

i

l

Strain Indicator

Type

1526

With

Accessories:

Multipoint

Selector and Control

Type

1544

Multipoint

Selector

Type

1545

The Type

1526

is a direct-reading digital

Strain

Indi-

cator ideally suited

to

the

measurement

of

static

strain,

as

well

as

dynamic

strain

up to a

frequency

of

300Hz

. It can be used

with

a

wide

range

of

strain

gauges (and

strain-gauge

transducer

s) in

quarter-

,

half-,

or

full-bridge

configuration.

Up to 5

strain-

gauge bridges may be

monitored

.

For

monitoring

up

to

400

bridge

configurations,

the

1

526

can be connected to a

Multipoint

Selector and

Control Type

1544

with

up

to

39

Multipoint

Selec-

tors

Type 1

545.

The Type 1

544

also has

an

output

socket

for

the

transfer

of

digital

information

via

the

B &K Interface Bus to

other

digital recorders and pro-

cessors.

BrUel

&

Kjcer

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STRAIN

INDICATOR

TYPE

1526

With

Accessories:

MULTIPOINT

SELECTOR

AND

CONTROL

TYPE

1544

MUlTIPOINT

SELECTOR TYPE

1545

Revision

April

1976

CONTENTS

1.

INTRODUCTION

AND

SPECIFICATIONS

(PRODUCT

DATA)

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

1

2.

CONTROLS

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

..

....

..

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

..

......

..

....

..

......

..

................ 9

2.1.

FRONT PANEL

OF

1526

.. .. ..

..........

.. .. ..

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

........

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

.........

..

9

2.2.

REAR

PANEL

OF

1526

.

..

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

.

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

11

2.3. FRONT PANEL

OF

1544

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

.

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

12

2.4.

REAR

PANEL

OF

1544

..

.

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

13

2.5. FRONT PANEL

OF

1545

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

....

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

.

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

15

2.6.

REAR

PANEL

OF

1545

..

.

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

...

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

15

3.

OPERATION

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

-

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

17

3.1.

SETIING-UP PROCEDURE, CHECK-LISTS

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

17

Setting up

the

1

526

alone ..................................

..

.........

..

........

.. .. ..

17

Setting up

the

1526

with

1544

and

1545(s)

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

.

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

18

Setting up a system

of

1

526,

1

544

and 1545(s)

with

digital data

transmission

via

the

B & K Interface Bus

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

19

3.2.

BRIDGE CONFIGURATIONS

ON

1526

........

..

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

..

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

20

Full-Bridge Configuration

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

.......

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

21

Half-Bridge

Configuration

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

21

Quarter-Bridge

Configuration

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

..

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

22

3.3. ADJUSTMENTS

ON

STRAIN INDICATOR

TYPE

1526

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

23

Selection

of

Bridge Excitation Voltage

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

23

Gauge Factor

Adjustment

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

24

Bridge Balance

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

.

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

.......

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

....

..

27

Balance Pot. Position

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

..

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

........

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

28

3.4.

1526

GROUND CONNECTIONS

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

28

3.5

. CABLE PREPARATION AND CONNECTION

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

29

3.6.

READING

THE

STRAIN

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

32

·

3.7.

MULTIPOINT MEASUREMENTS

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

.. ..

33

3.8. USE

OF

SEMICONDUCTOR STRAIN GAUGES

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

34

3.9

. USE

OF

READY-MADE STRAIN-GAUGE TRANSDUCERS

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

..

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

35

4. USE

WITH

OTHER

INSTRUMENTS

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

37

4.1.

USE

OF

1526

WITH A LEVEL RECORDER

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

.

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

37

Calibration

of

Level Recorder Type

2305

or

2307

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

37

Calibration

of

Portable Graphic Level Recorder Type

2306

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

38

Time-History

Recording

of

Strain

Levels

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

39

Serial Recording

of

Strain

Levels

from

many

Strain

Gauges

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

40

4.2.

USE

OF

THE

B & K INTERFACE BUS

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

40

4.3.

USE

OF

THE

ALPHANUMERIC

PRINTER

TYPE

2312

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

42

5.

CHARACTERISTICS

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

·

..........

~

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

44

5.1.

1526FILTERS

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

..

........

44

5.2

.

1526

OVERLOAD INDICATION

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

..

.....

45

Digital Overload ....

..

......

..

........

.. ..

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

..

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

..

......

.. ..

......

..

45

Analogue Overload ..................................................................................

45

5.3.

DIGITAL OUTPUTS ..................

..

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

.'

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

46

1526

Digital

Output

........

..

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

46

1

544

Digital

Output

..

.. ..

..

.. .. .. ..

.. .. ..

.. ..

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

..

.. .. .. ..

.. .. ..

..

.. ..

..

47

6. REFERENCE ..........

..

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

..

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

49

FEATURES

1526:

•

Direct

reading, easy to

operate

• Individual balance, and

bridge mode controls

for

5

measuring points

• Digital display

of

strain,

gauge factor, and

initial

balance condition

• Operating principle

that

eliminates

need

for

C-

balance

• Readings

from

0,

1

J1E

• Full, half, and

quarter

bridge

{with

adaptor)

configurations

• Use

with

500

to

20000

strain

gauges

• Gauge factor

adjustment

from

1,00

to

10,00

•

0,3

V excitation

for

low

heating effect

•

Low

pass filters, 3 Hz,

30Hz,

and

300Hz

• Hold

function

for

non-

repeating phenomena

• Overload indication

for

too

large a signal, capacitive

unbalance,

or

superimposed

hum

on

input

• Digital

output

{BCD)

•

Output

with

calibration

signal

for

recorder

• Oscilloscope

output

FEATURES 1

544:

• Individual balance, and

bridge mode controls

for

10 measuring points

• Logic control

for

systems

with

up to

400

measuring

points

•

Built-in

interface to B &K

Data Bus

•

Continuous

scan, single

scan, and remote step

scanning modes

1 h 1

f"'l':

types

1

526,

1

544,

and 1

545

Multipoint

Strain

Measurement

System

"'

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•

Ability

to ignore any

desired individual

point

in

the

scanning sequence

• Step intervals selectable

between

0,

1 s and 10 s

• Digital display

of

point

identity

number

FEATURES 1

545:

• Individual balance, and

bridge mode controls

for

10

measuring

points

•

Ability

to ignore any

desired individual

point

in

the

scanning sequence

• Logic control and

power

supply

from

1

544

1545

• Selectable position in scan

sequence

USES:

•

Measurement

of

deformation

of materials

•

Measurement

of bending,

torsion, and tensile stress

in

structures

•

Measurement

of strains at

up to

400

measuring

points

•

As

read-out for

transducers

with

sensitivities from

0,5

mV/V

to 5

mV/V

A complete system of

instruments

for making accurate strain measure-

ments on up to

400

measuring

points is available from B & K. The

system consists

of

the Strain Indica-

tor

Type 1

526,

the

Multipoint

Selec-

tor

and Control Type 1

544,

and the

Multipoint

Selector Type 1

545.

The basic measuring

instrument

in

the

system is

the

Strain

Indicator

Type 1

526

which

gives a direct

reading of

the

strain level measured

on a digital display. Five measuring

bridges can be connected

to

the

Strain

Indicator in any combination

Bridge

30kHz

Frequency Supply

_.,__

Divider & Amplitude

Clock Demodul- Stabilizer

Signal

Generator jator Driver

of

full,

or half-bridges. Adaptors are

available

to

permit

·measuremen't in

quarter-bridge configurations.

When

strain has to be measured

at more

than

five points,

the

Strain

Indicator can be connected to a

Mul-

tipoint

Selector and Control Type

1544

that

enables

the

Strain

Indica-

tor to scan a series of measuring

points automatically. Up to 1

0 mea-

suring points can be connected to a

Selector and Control

unit.

When

fur-

ther

points

must

be measured,

Mul-

tipoint

Selectors Type 1

545

with

I

Bridge Bridge

___.,__

Voltage

_.....,._

Power

~

Trans-

Amplifier

Attenuator former

I I

I

r

______

_j

I

I I

Inverter

Amplifier

I

(ij

.

~

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en

Cl

'i

u;

~

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Cl>

>

Cl>

.:

~

Cl>

C:

> 0

.: z

'-" Signal

..

De-

modulator

Strain Indicator

The Type 1

526

gives instantane-

ous direct readings

of

strain levels

on a digital display. The

instrument

is ideally suited to

the

measure-

ment

of static strain, and

it

can also

measure dynamic strains at frequen-

cies up to

300Hz.

It

includes a hold

function

to

permit

the

measurement

of

non-repeating phenomena; the

display

will

show

the

largest peak

occuring. In cases

where

both static

and dynamic strains are present,

the

two

components can be separ-

ated by use

of

the

hold function.

The

built-in

set

of

low

pass

filters

can also help separate static and dy-

namic

strains, besides being used

for

the

more normal

function

of

keeping spurious signals

out

of

the

measurement.

2

I I

Amplifier

Range

and

Gauge

Function

-

......

~

f---4--Attenuator Factor Selector

!Adjustment

I I

Average

___........__

Amplifier

.............._

Low

Pass

_...._

Detector

and Filter and

Filter

Peak

Hold

Circuit

Fig.1.

Block

diagram

of

the

Type

1526

Because

of

the

demodulator

prin-

ciple used in

the

Strain

Indicator re-

sistive and capacitive unbalance on

a strain gauge arrangement can be

balanced

out

together by one poten-

tiometer.

The Strain Indicator can be used

with

a

wide

range

of

resistance

strain gauges and

it

has a

full

scale

sensitivity from ±

200

microstrain

(J.le)

to ±

20000pe

with

one active

gauge. Analog outputs are available

to feed level recorders

or

oscillo-

scopes, and there is a

BCD

output

for

the

transfer

of

data

to

the

Type

1

544,

or

to

other

digital equipment.

Carrier Frequency System

The

Strain

Indicator uses a carrier

provision

for

10 points in each

unit

can be added to the arrangement.

Up to

39

Multipoint

Selectors can

be connected to the

Strain

Indicator

by a single Selector and Control

unit

to

give a

maximum

of

400

mea-

suring points. Point selection is con-

trolled by

the

Selector and Control

unit

which

also features a digital

display to indicate

the

identification

number

of

the

measuring

point

cur-

rently being sampled.

Manual

step,

or

automatic sweep

with

rates from

10

measuring points per second to

one

point

every 10 seconds are pos-

sible

with

this

arrangement.

~

Measuring

Point

r---.--

Selector

r-

Recorder

-Calibrator

II

~

Analog

to

Digital

Converter

r-------~

f Bridge

1

of

~

IVe

Bridge

I Conti-

I guration

~

Balance

Circuit

I

Term

r--o

~

r+y

inals

11

21

31

41

L

_______

I

_j

Offset Outpu

&Gain

~

---o

t 1

Adjustmen

Outpu

t2

Digital

Output

"'

?

Digital

Display

372001/1

frequency system

to

excite

the

mea-

suring bridge, thereby

eliminating

the

probl~ms

encountered

with

a

DC

system, such as thermocouple

effects, electrical and magnetic

noise. The carrier frequency system

also

allows

a

low

bridge excitation

voltage. The bridge voltage can be

set

to

3 V, 1V,

or

0,3

V.

With

0,3

V

and 1

20

0 gauges,

the

dissipation

will

be

only

0,

75

mW

per gauge,

which

makes

the

instrument

ideally

suitable

for

model testing on plas-

tics, epoxies, glass, and

other

mate-

rials

with

very

low

thermal

conduc-

tivity.

The Block Diagram in Fig.1

shows

the

inner

workings

of

the

Strain

Indicator. A Clock Generator

supplies a

30kHz

square

wave

sig-

nal

to

a Frequency Divider.

Two

sig-

nals come

out

of

the

Divider, one

of

them

is

the

3kHz

square

wave

exci-

tation

signal

for

the

measuring

bridge,

while

the

other

is a

6kHz

gating signal as

shown

in Fig.2.

Part of

the

bridge supply signal is

fed directly

to

a Signal Demodula-

tor,

and

part

of

the

signal passes

through

an Inverter and

then

into

the

Demodulator

.

Another

part

of

the

bridge supply

signal is conditioned and

then

passed

to

the

measuring bridge via

the

Measuring

Point Selector. This

excites

the

strain

gauges so

that

the

bridge arm resistances can be

compared. The resulting voltage

dif-

ference, representing

the

strain le-

vel, is fed

through

the

Function Se-

lector

to

an

Amplifier.

Gauge factor

adjustment

is accomplished by vary-

ing

the

gain of

this

Amplifier.

The

amplified signal is

then

further

con-

ditioned and amplified and fed

to

the

Signal Demodulator.

The Signal Demodulator gates

the

measuring signal, as

shown

in

Fig.3, and

allows

only

a portion

to

pass

through

into

the

measuring

section. This effectively eliminates

the

signal peaks

which

are caused

by

the

relatively high sensitivity

of

AC excited systems to reactive un-

balance,

i.e.

capacitive unbalance

due

to

long bridge leads. The de-

modulator

principle used in

this

in-

strument

permits

the

residual capac-

itive unbalance to be balanced out

by

the

resistance Balance Poten-

tiometer. Typically, a

0,05pF

un~al

ance on a

120

0 bridge

will

cause

an

error

in reading of < ± 1

digit

on

the

display in

the

1V

2000pe

range.

Measuring

Section

The demodulated signal passes

through

a

further

conditioning stage

to

the

Low

Pass Filter. The Filter

cut-off

frequency can be set

in

three

steps, 3 Hz,

30Hz,

and

300Hz.

The filtered signal is fed

di-

rectly

to

Output

2, and also

through

a

circuit

with

adjustable

"Gain"

and

"Offset"

to

Output

1.

Output

2

gives ±10 V

for

full

range

of

the

dis-

play, and is intended

for

feeding an

oscilloscope.

Output

1 is

meant

for

connection

to

Level Recorders Type

2305,

Type

2306,

and Type

2307,

or

to

ordinary voltmeters. The adjus-

Clock Generator Signal

372002

Fig.2.

Bridge

and

demodulator

signals

table

·:Gain"

and

"Offset"

make

it

easy

to

set up a

dynamic

range

of

the

output

signal

that

gives optimal

use of

the

Level Recorder,

to

obtain

a calibrated trace on pre-printed

chart

paper.

The

Strain

Indicator contains both

an Average Detector and a Peak

Hold Circuit. Normally, measure-

ments

will

be made

with

the

Aver-

age Detector

which

is suitable

for

steady state

or

slowly

varying static

strains.

When

a rapidly varying

strain is being measured,

the

Hold

Max.

"On"

button

should be

pushed

then

the

display

will

indi-

cate

the

largest peak regardless of

sign and time.

When

combined

static and

dynamic

strains are pres-

ent

the

Hold

function

can be used

with

the

Low

Pass Filters

to

separ-

ate

them

and measure

the

value

of

each component.

The Digital Display is a seven seg-

ment

gas discharge display

with

plus and

minus

signs and 3 1/ 2 di-

gits. The display can be

switched

to

indicate several

different

parame-

ters by

the

front

panel

"Function"

selector.

When

"Operate"

is se-

lected,

the

Display indicates

strain

Signal

from

bridge

with

capacitive

unba~ance

Without

capacitive unbalance

Bridge Supply Signal

372003

Fig.3

.

Functions

of

the

different

signals

levels directly in microstrain units.

Selection of

"Gauge

Factor

Adj."

brings

the

value of

the

gauge factor

in use on display, so

that

it can be

adjusted by

the

Gauge Factor poten-

tiometer. The gauge factor can be

adjusted over

the

range between ap-

proximately

0,90

and

10,50

to

match

the

characteristics

of

the

strain

gauges in use.

When

the

Function selector is

switched

to

"Balance

Pot.

Position",

a

number

indicating

the

position of

the

Bal-

ance potentiometer

will

be dis-

played. This is very useful in

the

types of test

where

it is

not

possible

to

unload

the

test piece and come

back

to

the

zero position. In these

cases

the

initial

balance can be

noted

for

future

reference.

A Digital

Output

is available

from

a

multipin

socket

on

the

rear

panel. This

output

permits

the

trans-

fer

of

strain

level data in parallel in

a BCD coded form

to

the

Type 1

544

or

to

other

digital equipment.

Measuring

Bridges

There are five balancing

networks

in

the

Strain

Indicator, and each

one has its

own

Balance Poten-

tiometer

on the

front

panel. The con-

nections

for

the

first

measuring

point

are on

the

front

of

the

instru-

ment,

while

the

other

four

are ar-

ranged on

the

rear. The connec-

tions

for

one

point

consist of

four

terminals,

two

for

the

excitation volt-

age, and

two

for

the

measuring volt-

age. Each measuring

point

has its

own

bridge mode selector near its

set of terminals. The selector ean

be

switched

to

either

"Full

Bridge",

with

four

strain

gauges

or

external

resistors connected in a

Wheat-

stone measuring bridge,

or

to

"Half

Bridge"

with

the

measuring

circuit

consisting of

two

external strain

gauges or resistors, and

two

cali-

brated 1

kO

internal resistors

to

complete

the

bridge.

The

Measuring

Point Selector

switches

the

excitation voltage in

turn

to each measuring point, and

at

the

same

time

connects

the

rele-

vant

point

to

the

measuring section

so

that

the

strain level at

that

point

can be measured.

A

plug-in

Quarter

Bridge Adaptor

is supplied

with

the

instrument

so

3

that

measurements can be made

with

a single strain gauge. The

standard

Adaptor

contains a

120

0

dummy

gauge, andan Adaptor

with

a

350

n

dummy

gauge is

_.

also

_.

avail-

able. _Both Adaptors can be

em-

ployed

in

either

two

lead

or

three

lead circuits.

Another

important

accessory sup-

plied

with

the

-

instrument

is a plug-

in Calibration Bridge so

that

the

dis-

play can be calibrated

with

an accu-

racy

of

0,1%

when

the

Strain

Indica-

tor is to be used as a transducer

read out.

Using

the

Digital

Display

With

correct use of

the

"Hold"

function,

the

"Balance"

control, the

Low

Pass Filters, and

the

plus and

minus

signs on

the

display,

the

val-

ues of interest can be determined

for

any type of signal

with

the

same

degree

of

accuracy as

that

of

a pure

static signal.

An

oscilloscope con-

nected to

Output

2 helps

to

verify

the

type of signal,

but

is not re-

quired

for

the

measurement

of

the

level.

The sketches in Figs.4 to 9

show

how

measurements can be made

on various types

of

signal.

Multipoint

Selectors

The

Multipoint

Selector and Con-

trol Type 1

544

is

the

master con-

trol

unit

for

strain

measurement

sys-

tems consisting of up to

39

Multi-

point

Selectors Type 1

545

con-

nected via itself to

the

same

Strain

Indicator Type 1

526.

In addition

to

its control circuitry,

the

Selector

and Control

unit

contains facilities

for

connecting and

switching

10

measuring points.

Multipoint

Selec-

tors Type 1

545

each contain pas-

sive

circuitry

for

connecting and

switching

10 measuring points. A

decade identification

number

can be

set on

the

Multipoint

Selector

to

de-

termine

its place

in

a scan se-

quence.

As

Multipoint

Selectors Type

1

545

have no

power

supply,

they

4

Strain

time

273130

Fig.4

.

For

this

type

of

signal

the

± sign

shifts

both

with

and

without

the

"Hold

Max."

depressed.

Value

+

or

-

A is measured

in

pos

.

"Hold

Max

."

273129

Fig.&.

With

this

type

of

signal value

-B

is

measured

until

time

t1

where

± sign

starts

shifting,

indicating

that

dy-

namic

signal is present.

If

"Hold

Max."

is depressed

-A

is

indicated

after

time

t1

~Time

750495

Fig.B.

In

this

case

the

average

value

B is in-

dicated

when

the

"Hold

Max."

is

not

depressed. +A is

indicated

in

pos.

"Hold

Max

."

must

be connected

to

a

Multipoint

Selector and Control Type 1

544

when

in

use.

Measuring

points are selected

for

connections

to

the

Strain

Indicator

one at a

time

in a predetermined se-

quence, so

that

the

strain

level at

each measuring

point

can be mea-

sured and displayed. The measuring

points can be scanned automatically

in sequence at a rate preselected

on

the

Selector and Control, be

stepped in sequence by a

manual

control or be operated by a remote

switch.

The identification

number

of

the measuring

point

currently

con-

nected to

the

Strain

Indicator is

indi-

cated on a

three

digit

display on

the

Selector and Control,

while

an LED

is

lit

below

the

balance control

of

273131

Fig.5.

With

this

type

of

signal

the

± sign

shifts

without

"Hold

Max."

de-

pressed.

Value

+ A

is

measured

in

pos.

"Hold

Max.".

When

BALANCE

CONTROL

is adjusted

until

± sign

also

shifts

with

"Hold

Max."

de-

pressed, value

(A-B)

is measured

in

pos.

"Hold

Max."

[A\

~

"''··

t,\J'T\V""'

273132

Fig.7.

With

this

type

of

signal, and

the

"Hold

Max."

depressed, +A is

indi-

cated

until

a

numerically

larger

signal

appears,

in

this

case

-B.

whereafter

-B

is

indicated

Strain

~-.

~t;m,

273133

Fig.9.

For

this

signal

with

a

lower

frequency

dynamic

component

than

in

Fig.B.

the

value

B can

be

measured

using

one

of

the

Low

Pass Filters.

the

relevant

point

as an additional

indication.

Individual

Multipoint

Selectors

Type 1

545,

representing

whole

de-

cades

of

measuring points, can be

switched

to

another

place in

the

scanning sequence by changing

the

decade

identification

number

.

If

the

number

selected is

00,

the

whole

decade

will

be by-passed.

When

ne-

cessary, individual measuring

points

can be

switched

out, so

that

the

scan passes over

them

in

the

automatic sequence. A single mea-

suring

point

can be selected

for

bal-

ancing

or

measurement

by a

"Call"

switch,

and

if

several points are

called

in

this

way, a restricted auto-

matic

sweep sequence over

just

these points can be made.

The Selector and Control

unit

also

contains

a

built-in

interface

that

sa-

tisfies

the

requirements

of

the

B & K Data Bus System.

This

makes

it

possible

to

record

the

strain

level

and

point

identification

digitally,

and gives

the

further

possibility

of

data

acquisition

by a computer.

Control

Logic

Fig.10 is a Block Diagram

of

the

Multipoint

Selector and Control

Type

1544

. The

portion

of

the

dia-

gram

enclosed

within

the

broken

line

shows

the

components

that

are

also

present

in

the

Multipoint

Selec-

tor

Type 1

545.

The

Control Logic in

the

Selector

and Control

unit

receives

informa-

tion

on

its

own

control settings and

those

of

Multipoint

Selectors con-

nected

to

it, and controls

the

selec-

tion

of

the

measuring

points. The

Logic

unit

also receives

strain

level

data

from

the

Strain

Indicator and

retransmits

them

via

the

Interface,

together

with

the

measuring

point

identification

number,

for

print

out

or

subsequent

digital

processing

when

necessary.

Data from

1526

To

1526

I

Interval

Selector Timer

0,

1/0,

5/1/

1----

and

2/5/10s

Counter

/I

Clock Control

Logic

I Scanning

Remote

BCD

Remote Address

A series

of

impulses

from

the

Clock

Generator

is fed

through

the

Control Logic

to

drive

the

. Address

Counter,

which

transmits

BCD

coded addresses

with

10

microsec-

onds

between

them.

The Address

Counter

starts

with

measuring

point

number

000,

and

counts

up

to

mea-

suring

point

number

400

which

is

interpreted

by

the

receivers as

000,

so

that

the

address cycle is re-

peated. The coded addresses are re-

ceived by

the

Decade Decoders

of

all

instruments

in

the

measuring

ar-

rangement. The Decade Decoder in

the

Selector and Control Type 1

544

is

permanently

set

to

decade

num-

ber

0,

while

the

Decade Decoders

in

the

Multipoint

Selectors Type

1

545

can be set

to

any

number

be-

tween

1 and

39

by a

two

knob De-

cade Selector.

When

·

the

Decade

Decoder recognises its

own

address

code,

it

triggers

the

BCD to 10 Line

Decoder

which

in

turn

drives

the

relevant Relay coil to achieve selec-

tion

of

the

correct

measuring

point.

Measuring

Point

Circuits

Each

measuring

point

has its

own

set

of

four

terminals

on

the

rear

panel

of

a Selector and Control

unit

or

a

Multipoint

Selector,

with

10

sets

of

terminals

per

instrument.

When

the

Relay operates

to

connect

a

measuring

point,

one

pair

of

termi-

nals

carries

the

excitation voltage

for

the

individual

measuring

bridge

received

through

two

leads

of

a

four

conductor

cable

from

the

Strain

Indi-

cator. The

other

pair

of

terminals

re-

ceives

the

bridge

output

signal

that

is

to

be passed

to

the

measuring

section

of

the

Strain

Indicator by

the

other

two

leads

in

the

cable.

The individual

measuring

poi'i'lts

are each equipped

with

a Bridge

Mode

Selector and Balance Poten-

tiometer

similar

to

those

on

the

Strain

Indicator. These

allow

any

combination

of

full

or

half

bridges,

or

quarter

bridges

(with

adaptor)

to

be connected and balanced. In

the

Relay Coil

circuit

of

each

measuring

point,

there

is an

LED

that

lights

to

indicate operation

of

the

Relay and

connection

of

the

measuring

point.

There is also a

three

pos1t1on

"On/Off/Call"

function

switch

for

each

measuring

point. The

"On/Off/

Call"

switches,

on

all Selector

in-

B & K Interface

This Part

is

Repeated in

Type

1545

Bus

,----------,

I I

-I I

-On/

-

Off/

-

Call

I I Switches in

1545s

I I

On/

I

Off/

I

Call

I

I Switches I

I

.~

I

I I

f I I

. 7 • 7 I

--

-.

Start

I

~

Reset LEOs I -

To

10

Sets

Stoo

Power

of

Bridge

end

of

Sca_n

Interface

----

Supply

~

and

f.---

Relays :

Relay Coils Terminals

Print '!"'

.

~

f

./

~

"!'

I -

t I

I

I I

Decade I

:To

Bridge

and

BCD

to

I~

P>ntinuous

t---

Display Terminals

Circuit Single

Counter

10

Line

-on

1526

Reiet

Decoders I -

I

TI

7 I

I

..

To

1545s

I Addresses

to

Decoders in

1545s

I •

L

_________

J

75Q492

Fig.10.

Block

Diagram

for

Type

1544

and Type

1545

5

To

Next Bridge

~~----------~~---------+----~

I

"0-----=4

I

3 Balance &

Bridge Mode

~~------------~--------------~

I 2

2 3 4 D Bridge Terminals

To

Bridge Terminals

on 1526 Relay

750509

Fig.11.

Positions

of

the

relays

struments

are connected in parallel

to carry information on

the

function

required for the individual measur-

ing point circuits. The Clock pulses

to the Address Counter are inter-

rupted by

the

Control Logic

when

an address

that

has

"Call"

or

"On"

selected is reached. If

function

switches are set in position

"Off",

the

count continues and

the

rele-

vant measuring points are passed

over. The

"Call"

function

has a

higher priority

than

"On",

so

that

where

any switches are set to

"Call",

the scan

will

not stop at

"On"

switches,

but

make a sweep

of

"Call"

positions only.

When

a

single measuring

point

has been

called, the scan

will

remain

at

this

position.

The scan sequence can be started

at any

point

by calling

that

point

and

then

releasing it.

The

number

of the measuring

point

being sampled is indicated on

a Digital Display,

which

receives

and decodes the

BCD

output

from

the

Address Counter.

Dwell

Time

Selection

At

the

same

time

as

the

Clock

pulses are interrupted, the Control

Logic resets and starts a Timer

that

emits an impulse every

tenth

of

a

second. These pulses are counted,

and

when

the counted interval

matches the

time

selected by the

Step Interval buttons on the Selec-

tor

and Control, the Clock pulses to

the

Address Counter are resumed

and

the

scan moves on to

the

Dwell

times

of

0,1 s,

0,

5 s, 1 s, 2 s, 5 s, and 10

seconds can be selected.

6

If

different

dwell

time

intervals

are . required, or if

the

measuring

method requires it, point selection

can

be

accomplished by means

of

the Remote Tri'gger input. The Re-

mote Circuit accepts signals

from

a

TTL

source, and can also be used

with

the

cam

switch

of

a Level Re-

corder Type

2305, 2306,

or

2307.

A scanning rate

of

ten

points per

second is

the

maximum possible.

Scanning modes

"Remote"

step

trig-

gering,

"Cont"inuous

scan,

"Single"

scan, and

"Reset"

to

000

can be selected by push buttons on

the Selector and Control

unit.

B & K

Interface

Bus

The

built-in

Interface Bus con-

tained in

the

Selector and Control

collects the BCD coded addresses

from

the

Address Counter and

strain level data from

the

Type

1

526.

It delivers

them

in ASCII

code

to

the

Interface Bus

with

the

proper

format

for

printing

out,

with

one line

for

each measuring point.

The Interface is

similar

to a pro-

posed

IEC

Standard

with

respect to

the byte-serial transmission

of

data

and the control signals,

but

it

is not

addressable. . Data

transfer

is

asynchronous and

the

transfer

rate

is governed by

the

slowest receiver

connected to

the

bus.

If

the

receiver

is too

slow

for

the

scanning speed

selected on

the

Type

1544,

the

step intervals

will

be

prolonged by

ttie interface

circuit

so

that

the

re-

ceiver governs

the

scanning rate.

Generally, several

transmitters

and receivers may be connected to

the B & K Interface Bus

where

a

controller is capable

of

addressing

them

and assigning individual

tasks. The Type

1544

is a

"Talk

Al-

ways"

device, and

if

it

is part

of

a

controlled system, as described

above,

it

can be connected and dis-

connected

when

necessary in

the

measuring sequence,

either

manu-

ally by

the

"Read

Out"

command

from

the

Type

1526,

or by

the

"Remote Enable" line from

the

con-

troller.

A scan can be initiated externally

from

the

Interface Bus. It is also

possible to make

on-line

calcula-

tions,

of

strains measured by ro-

sette gauges

for

example,

when

a

computer is connected to

the

Bus.

The Interface

circuit

will

"Hand-

shake"

with

most

equipmen~

follow-

ing

the

proposed

IEC

Standard,

but

according to

the

Standard, compati-

bility

with

all receivers cannot be

guaranteed.

System

Connection

Fig.

12

shows

how

the

strain mea-

suring system should be connecte·d.

Note

that

the

four

conductor cable

connecting

the

Strain

Indicator

with

1526

1544

1545

Fig.12.

Inter-connection

of

the

system

the

Multipoint

Selector

and Control,

and

the

Multipoint

Selectors should

be kept as

short

as possible,

with

a

recommended

conductor

cross sec-

tion

of

at least

0,

75

square

millime-

ters (approx. 19 gauge)

to

minimise

the

influence

of

conductor

resist-

ance.

Connection of Other B

8t

K

Equipment

Fig.13

indicates typical analysis

and read-out possibilities

for

the

Strain

Measurement

System. For

di-

rect

frequency

analysis

of

dynamic

strain,

any

of

the

B & K analyzers

can be connected and a spectro-

gram

plotted on a level recorder.

For

direct

recording

of

static

strain,

and

dynamic

strain

up to about

10Hz,

a Level Recorder Type

2305

or

Type

2307

can be used. For stor-

age and

frequency

transformation

of

recorded data,

the

Tape recorder

Type

7003

can be used

with

advan-

tage, Speed-up at play-back

allows

analysis

of

very

low

frequency

sig-

nals

with

ordinary

analyzing equip-

ment.

Slow-down

at

play-back al-

lows

direct

recording on level record-

ers

of

phenomena

that

are

other-

wise

changing

too rapidly. A loop

•

·····~

@•

Oscilloscope

Frequency

Analyzer

Type

2010,2120 or 2114

Level

Recorder

2305

or

2307

••

1545

Teletypewriter

6401

750494/1

Fig.

13.

Typical

analysis

and

read-out

possibilities

with

the

Strain

Measurement

System

casette

for

the

recorder

allows

ana-

iysis

of

impulsive

signals. For

this

type

of

signal,

the

Digital Event Re-

corder Type

7502

can also be used,

g1vmg

a

much

larger frequency

transformation

ratio.

Specifications 1

544

and 1

545

Bridge

Connections:

10

measuring points can be connected

in any combination of

full

and half

bridges and also

quarter

bridges

(with

adaptor)

Bridge

Excitation:

0.3.

1. and

3V

. derived from the

1526

Bridge

Balance:

With

gauge factor

2,00

and resistance

1200,

up to ± 10000J.1€ can be bal-

anced

out

Balance resolution is switchable i. e.

± 2%. ±

0,6%,

±

0.4%.

and±

0,1%

A

50pF

change

to

one

1200

gauge

will

shift

the

balance by less

than

1

J.l€

Measuring

Accuracy

(with

1

20

0 gauges

and 1 or 3 V excitation):

Accuracy relative to

1526

: ±

0,2%

Accuracy relative

to

any measuring point

in

the

same Selector: ± 0.

1%

Step

Intervals

(controlled by

1544)

:

0,1 s.

0,5s,

1,0s,

2,0s

,

5,0s.

and

10,0s

Accuracy: ±

5%

Digital

Input

(1

544

only):

BCD coded strain levels from

Strain

Indi-

cator

BCD

coded measuring

point

identification

numbers

from

Multipoint

Selectors

B

&.

K

Interface

Bus

(1544

only):

ASCII coded

strain

levels, and

point

iden-

tification

Accuracy

of

strain

level data relative to

1526

display: ± 1

digit

Digital

Display

(1

544

only):

7-segment

neon gas discharge display

with

3 digits indicating identity of meas-

uring

point

being sampled

Scanning

Modes:

(controlled by

1544)

:

Single

scan,

Continuous

scan, controlled

by

internal

Logic in 1

544

Remote step triggered by external

switch

or

TIL

level

Power

Supply:

1

00

to

240

V AC,

50

to

400Hz

Power

Consumption:

1

544

: 10 W plus 1

545s

1

545

: 2 W (from 1

544)

Operating

Temperature:

+5°

to+

40°C

(+

40°

to 1

04°F)

Humidity

Range:

0

to

90%

relative

humidity

Cabinet:

Supplied

as

model A

(lightweight

metal

cabinet). model B (model A in mahogany

cabinet) or model C (as A

but

with

flanges

for

standard 1

9"

racks)

Dimensions

(A

cabinet):

Height

133

mm

(5,25

in)

Width

:

430

mm

(16,9 in)

Depth:

200

mm

(7,9

in)

Weight:

1544:

6,5kg(14,31b)

1545:

4,5

kg

(1

0 lb)

Accessories

Included:

Power cord

(1544)

25-lead

flat

cable

with

D-connectors

AQ

0138

(1544)

26-lead

flat

cable, 4 m

with

26

pole con-

nector

AQ

0115

(1544)

26-lead

flat

cable connector

JJ

2604

(

1544/

1545)

8 pin plug

JP

0802

(1

544)

7

Bridge

Excitation:

0,3

, 1 and

3V

3 kHz square wave

Range:

± 199,9JJ€, ± 1999JJ€, ±

19990

*

JJ€

For 1 active gauge and

with

correct

gauge factor setting. ± 199,9JJ€ only

with

3 V excitation voltage ·

Gauge

factor:

Continuous adjustment wi

th

ten-

turn

pot-

entiometer from 1,

00

to

10,00

Gauge factor shown on display

Accuracy:

Without

external calibration bridge:

±0,

5%

± 1

digit

for gauge factor < 2

±

0,25%

± 1

digit

for gauge factor

;;;.

2

With

external calibration bridge:

±o.1% ± 1

digit

The capacitive unbalance

of

a 1

20

0

gauge must be less

than

10

000

pF

in

the 200JJ€ range and

30000pF

in all

other ranges

Linearity:

± 1

digit

Noise

on

display:

± 1

digit

Temperature

Drift:

<

0,05%

per °C

Bridge

Balance:

With

gauge factor 2,

00

and resistance

1200

, up to ±

10000JJ€

can be bal-

anced

out

Balance resolution is switchable i. e.

± 2%, ± 0,6%, ±

0,4%,

and±

0,1%

A

50

pF

change to one 1

20

0 gauge

will

shift

the

balance by less

than

1JJ€

The Balance Potentiometer position can

be

shown

on

the

1526

display

Specifications 1

526

Filters:

Low-pass

filter

with

3 dB

limits

at 3,

30,

and

300Hz

.

At

the

excitation frequency

the

damping

with

the

300Hz

filter

will

be

70dB

(3000

:1)

Rectifier:

Average

: Response

time

referred to

the

digital display is

30

ms.

With

"Reset"

button depressed approx. 3 s

Peak Hold:

Decay rate 1

digit

per 10 s

Pulse duration

for

accuracy

within

the

above stated

Without

filters: Pt

;;;.

4 ms

With

300Hz

filter

: Pt

;;;.

6 ms

With

30Hz

filter

: Pt

;;;.

30

ms

With

3Hz

filter

: Pt

;;;.

300

ms

Outputs:

Output

1: ± 0,7 V to ± 4 V for maxi

mum

reading on display;

with

offset possibility

of±

4V

.

Rg

=

2200

Output

2: ± 1

OV

for maximum reading

on display.

Rg

=

2200

Lineari

ty

better than ±

0,1%

Digital

Output:

17

data lines for 3

full

and 2

half

BCD

characters, sign, decimal point and over-

load indication

Levels according to

SN74/TTL

series

(OV

and+

5 V positive true)

Control

signal

out:

Data Ready

Control

signal in: Data Request

Display

:

7-segment

neon

~

gas

discharge

Shows±

and 3 1/ 2

digit*

External

circuits

:

Full and

half

bridge

which

may be inde-

pendently set and mixed on the five mea-

suring points

With

an accessory box also

quarter

bridge

circuit

can be used in

two

or three

wire

configuration

Power

Supply:

100

,

115

,

127, 150,

220

,

240V

AC,

± 10%

50

to

400Hz

Power

Consumption:

10W

Operating

Temperature

:

+ 5 to

40°C

(40

to 104°F)

Humidity

Range:

0 to

90%

relative

humidity

Cabinet:

Supplied as model A

(lightweight

metal

cabinet), model B (model A

in

mahogany

cabinet)

or

model C (as A but

with

flanges

for

standard 1

9"

racks)

Dimensions

(A

cabinet):

Height

133

mm

(5

,

25

in)

Width

:

430

mm

(

16,9

in)

Depth:

200

mm

(7

,9 in)

Weight:

4,6

kg

(10 I

b)

Accessories

Included:

Power cord

Calibration Bridge

ZR

0013

Quarter Bridge Adaptor

ZR

001

4

* In

19

990

range

the

last zero indicates range

only, resolution is 1

Op€

2.1.

FRONT

PANEL

OF

1526

POWER:

RANGE

J.LSTRAIN

BRIDGE EXCITATION:

FUNCTION:

2.

CONTROLS

8tui~

lnolo.,tor

Ty.,.

1521

)i

I

-

--

Fig. 2. 1.

Front

Panel

of

Type

1526

Toggle

switch

to

switch

the

instrument

on and off.

Seven-position rotary

switch

used to select

the

measurement

range

and excitation voltage. There is a choice

of

2000J.Lstrain

(J.Le)

or

20000J.Le

with

a bridge excitation

of

0,3

V

or

1 V, and a choice

of

200,

2000,

or 20000J.Le

with

a bridge excitation

of

3 V. (See

sections

3.6

and

3.3

.1.)

Four-position

rotary

switch

used to select

the

measurement

being

shown

on

the

DIGITAL DISPLAY, as follows:

"Balance

Pot.

Position"

:

"Gauge

Factor

Adj.":

"Operate":

"Recorder

Cal.":

In

this

position

the

balance potentiome-

ter

position is displayed. This is purely a

number

for

referencing

the

balance of

the

strain-gauge bridge at a given

time

.

(See section

3.3.4.)

displays

the

gauge factor;

gives

the

strain

directly

in

J.LStrain;

provides a calibration voltage

output

from

the

rear-

panel OUTPUT sockets.

The signal is intended

for

a Level Record-

er

which

gives a deflection equivalent

to the strain level

shown

on the DIGI-

TAL DISPLAY. (See sections

4.1.1

and

4.1.2.)

9

RECORDER CALIBRATION:

GAUGE FACTOR:

OUTPUT 1,

"Gain",

"Offset":

READ OUT:

HOLD

MAX.,

"On":

HOLD

MAX.,

"Reset":

FILTER

"3Hz",

"30Hz",

"300Hz":

MEASURING POINT SELECTOR:

MEASURING POINT 1:

BRIDGE MODE SWITCH:

BALANCE POTENTIOMETERS:

DIGITAL DISPLAY:

10

Six-position rotary

switch

for

selecting calibration levels. There are

six

levels: 0;

1;

2,5;

5; 10; and

20,

which

give readings corresponding

to

0%; 5%;

12,5%;

25%; 50%; and

100%

of

the

full

range in each

of

the

three

strain

ranges. (See sections

4.1.1

and

4.1.2.)

Ten-turn

potentiometer

used to

adjust

the

instrument

for

the

gauge fac-

tor

of

the

strain

gauge or

other

transducer

being used.

The gauge factor is adjustable

from

1

,00

to 1

0,00.

It can also be used

to give

direct

readings

from

quarter,

half

and

full

bridges. (See

section

3.3.2.)

Two

ten-turn

potentiometers used to adjust

the

gain

of

the

output

sig-

nal at OUTPUT 1 and to offset

the

base level

of

the

signal. (See

section 4.1.1

.)

Push

button

for

signalling

to digital

equipment

that

it

should

com-

mence readout.

Push

button

to activate

maximum

strain hold

circuit.

Inner

position

for

"On",

outer

position

for

"Off".

Non-locking push

button

to reset

maximum

hold

circuit.

Can also be

used as an extra

filter.

Wait

3 seconds before taking a reading.

Push

buttons

for

suppressing

the

high-frequency

content

of

signals.

As

one

button

is pushed, the others are released.

Five-position rotary

switch

for

selecting

which

of

the

measuring

points

is connected to the bridge supply and reading facility.

This consists

of

four

screw-down

terminals

to

which

the

leads

from

the strain gauges are attached.

Terminals

1 and 2 deliver

the

bridge

excitation voltage, and

terminals

3 and 4 receive

the

bridge

output

volt-

age

to

the

meter. Diagrams on

either

side

of

the

MEASURING POINT

SELECTOR

show

how

the

leads should be connected

for

full-bridge

or

half-bridge operation. (In half-bridge diagram, A = active gauge, D =

dummy

gauge.) Quarter-bridge operation requires

the

use

of

the

Adap-

tor

ZR

0014.

(See section

3.2.3.)

There is one

of

these to

the

left

of

the

set

of

screw-down

terminals

of

each MEASURING POINT. This

ten-position

switch

sets up

the

1526

for Full-

or

Half-Bridge configurations. The percentage values

refer

to

balance resolution. (See section

3.2.)

Ten-turn

potentiometers

for

balancing

out

resistive and capacitive

un-

balances in

the

measuring bridge. There is one

for

each MEASURING

POINT. (See sections

3.3.3

and

3.3.4.)

The knobs can be removed

from

the

spindles

if

desired to

prevent

accidential

movement

when

the

potentiometers have been adjusted.

Screwdriver-adjustment

is possi-

ble

when

the

knobs are removed.

Indicates instantaneous

numerical

value

of

FUNCTION selected, at

sam-

pling intervals

of

200

ms.

(With

the

READ OUT

button

depressed,

the

sampling interval is

30

ms.) Flashes on and

off

in

the

case

of

an over-

load condition, see section 5.2.

2.2.

REAR PANEL OF

1526

FUSE

AND

VOLTAGE

SELECTOR:

MEASURING POINTS

2, 3, 4,

5:

OUTPUTS 1, 2:

DIGITAL OUTPUT

"To

1

544":

POWER:

•

@

~

il

Otgit

at

OutPut

Fig.2. 2. Rear

Panel

of

Type

1526

Contains a

0,2

A

fuse

(20

x 5

mm)

for

200-240

V use. A

0,5

A

fuse

should

be used

for

lower

supply voltages. To change

the

fuse

or

supply

voltage, remove

the

star-shaped knob in

the

centre

(a

quarter

turn

is

enough). The voltage can be adjusted

with

a

wide-bladed

screwdriver

or

a coin. Replace

the

star-shaped knob

after

voltage

adjustment

and/or

fuse

replacement.

Identical to MEASURING POINT 1 on

the

front

panel.

Coaxial sockets

for

output

of

DC

voltages to

other

instruments.

See

their

individual specifications in Chapter 1. Accept standard 8 & K coax-

ial plugs

JP

0101.

OUTPUT 1 has adjustable

"Gain"

and

"Offset"

controls

on

the

front

panel

of

the

instrument,

and is

primarily

intended

for

use

with

8 & K

level recorders (see section 4.1

).

OUTPUT 2 has no controls, and is intended

for

use

with

oscilloscopes,

etc..

Two

supplementary

sockets connected

to

chassis

ground

are also pro-

vided,

which

accept plugs

JB

0002

. (See section 3.1 .2

for

the

connec-

tion

of

this

socket to

the

1

544.)

Twenty-five-pin

socket

connector

for

the

output

of

measurements

to

the

1

544.

Accepts plug

JP

2500

or

cable

AQ

0138.

This cable is

only

required

if

the

1

544

is

to

be used on

the

8 & K Interface Bus. (See

sections

3.1.2

and 3.1 .3.) The pin

connections

of

the

socket are given

in section

5.3.1.

Socket

for

connection

of

the

1526

to

the

mains.

For cable

connections

see

Fig.2.3.

11

Blue Neutral

Brown

~~P~f;er

~

Live

( n

11

J

Green

and

Yellow Ground

172246

Fig. 2. 3. Conn'ection

of

Power

Cable

AN

0010

2.3.

FRONT

PANEL OF

1544

..-'-----

StEP

lntEfval

s

----.

0.

1 0.& '!

10

I

II

II II

II

!

Pow~r

r-

Scanning-.,

Remotf' Com

$HtgJ~

A-e$~H

POWER:

SCANNING:

12

8al.,ne~

POlttUJOO\.!it&t

On

Off

C111ll

Full

Bt

idgot

. . .

~

. , . . .

..

Fig. 2. 4. Front

Panel

of

Type

1544

Toggle

switch

to

switch

the

instrument

on and off.

Four

push-button

switches

for

controlling

the

mode

of

scanning

of

the

MEASURING POINTS. These are as follows:

"Remote

Step"

triggering:

"Continuous"

scan:

"Single"

scan:

"Reset":

controlled by

the

REMOTE STEP CON-

TROL SOCKET on

the

rear

of

the

1

544;

~teps

one

point

at

every

trigger

pulse;

continues

to scan

the

selected MEASUR-

ING POINTS

until

manually

(or re-

motely) stopped;

initiates

one scan

only

over

the

selected

MEASURING POINTS;

selects MEASURING POINT

"000".

To

start

the

scan at some

arbitrary

MEASURING POINT,

"Call"

that

MEASURING POINT

with

the

POINT-SELECTOR SWITCH, and

then

reset

the

switch

to

"On".

STEP

INTERVAL

S:

DIGITAL DISPLAY:

BALANCE POTENTIOMETER:

POINT-SELECTOR SWITCH:

INDICATOR LAMP:

BRIDGE MODE SWITCH:

2.4.

REAR

PANEL

OF

1544

Each

of

these 6

push-button

switches

selects a required

dwell

time

during

which

the

scan remains at each MEASURING POINT. Times

of

0,1;

0,5;

1;

2;

5;

and

10

s are available.

Indicates

the

number

of

the

MEASURING POINT in use.

Ten-turn

potentiometer

for

balancing

out

resistive and capacitive

unbal-

ances in

the

measuring bridge. There is one

for

each MEASURING

POINT. (See sections

3.3.3

and

3.3.4.)

The knobs can be pulled

for-

ward

off

the

spindles

if

desired to prevent accidental

movement

when

the

potentiometers

have been adjusted.

Screwdriver-adjustment

is pos-

sible

when

the

knobs are removed.

Three-position

switch

for

controlling

the

scanning sequence. The posi-

tions

are as follows:

"Off":

"On":

"Call":

the

scan passes

the

MEASURING

POINT;

the

scan stops for

the

dwell

time

se-

lected, provided

that

no

switches

are

set to

"Call";

the

scan

will

now

stop

only

at MEASUR-

ING POINTS

with

their

switches

set to

"Call",

and

will

bypass those set to

"On"

or

"Off".

There is one

switch

for each MEASURING POINT.

A red lamp

which

lights

when

the

scan is

at

that

MEASURING POINT;

there

is one lamp

for

each point.

Ten-position

switch

to select Full-

or

Half-Bridge configuration. The per-

centage values refer to balance resolution. There is one

switch

for

each MEASURING POINT. (See section

3.2.)

Fig.2. 5. Rear Panel

of

Type

1544

13

MEASURING POINTS

0-9:

SIGNAL CONNECTION SOCKET:

DIGITAL DATA SOCKET

'To

1

526":

B & K INTERFACE BUS

SOCKET:

REMOTE STEP CONTROL

SOCKET:

Identical to MEASURING POINT 1 on

the

front

panel

of

the

1

526.

(See

section 2.1

.)

There is one set

of

controls on

the

front

panel

of

the

1544

for each

of

these

10

MEASURING POINTS.

The

remaining

set

of

4

screw-down

terminals

is

for

connection

of

the

signal cable

to

the

1526

and any

1545

in

the

system. (See

section 3.1 .2.)

Twenty-five-pin

socket

for

a data signal

from

the

DIGITAL OUTPUT

of

the

1526.

Accepts plug JP

2500

or

cable

AQ

0138.

There is a small

grounding

socket

just

above

this,

which

will

accept

plug

JB

0002.

(See sections

3.1.2

and

3.1.3

for

connection

of

these

sockets

to

the

1

526.)

Twenty-five-pin

socket

for

connecting

the

entire

strain-measuring

sys-

tem to

the

B & K Interface Bus (see sections 3. 1.3 and 4.2) for process-

ing

of

data. Accepts plug JP

2500

or cable

AO

0084.

The pin connec-

tions

of

the

socket are given in section

5.3.2.

Eight-pin DIN socket

for

accepting TTL (or other) signals to control step-

ping

of

scan. Each triggering

will

step

the

scanning to

the

SURING POINT

whose

POINT-SELECTOR SWITCH is set to

"On"

or

"Call"

.

Maximum

voltage

must

not

exceed TTL voltage. Can also be

used in

conjunction

with

the

cam

switch

of

B & K Level Recorders,

Types

2305,

2306

and

2307.

Accepts plug

JP

0802.

(See

Fig.2.6

for

connections.)

Connection

of

pins 2

and 6

to

pin 3 advances

scan

by

one step.

760248

Fig.2. 6.

1544

REMOTE STEP CONTROL SOCKET.

External

view

of

socket,

soldering

side

of

plug,

shown

DIGITAL CONTROL SOCKET

"To

1

54

5

":

FUSE

HOLDER:

VOLTAGE SELECTOR:

POWER:

14

Twenty-six-pin

socket

for

connecting

the

control cable

from

the

DIGI-

TAL CONTROL SOCKET

"To

1544/1545"

of

a

1545.

Accepts connec-

tor

JJ

2604

or cable

AQ

0115.

A

500

rnA fuse is contained

(20

x 5 mm)

for

use

with

voltages

of

200

-

240

V. For

lower

voltages (1

00

V and above) a 1 A fuse

should

be

used. To change

the

fuse,

unscrew

the

FUSE HOLDER, replace

the

fuse, and

screw

it

back again.

To

alter

the

VOLTAGE SELECTOR

for

a

different

mains

supply voltage,

insert a wide-bladed

screwdriver

or

a coin

into

the

slot and

turn

until

the correct voltage is adjacent to

the

small

arrow

at

the

top.

Socket

for

connection

of

the

instrument

to

the

mains. Accepts cable

AN

0010.

For connections, see

Fig.2.3.

BRUEL & KJAER 1526 User manual

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