Bruel & kjaer 2512 User manual

Instruction

Manual

Human-Response Vibration Meter Type 2512

Type

2512

liuman-R&IIIOl'IH

Vibration Metet

033-0659

Whole Body

1 - 80Hz

l

xv~!z

Comfort

f:

..

a~.

~-

......

··

...•......

··

···

Ptofffflencv

>

l:)(j)Osore

timlt

•

O,t - 0,

63Ht

Motion

Sid<ness

•

t

-·::uced

Comfort

Severe

.

Oi$Comlort

..

Srilal&Kjair

28V

2mA

The

2512

Is

a single, easy to operate Instru-

ment designed for the evaluation of the effects

of vibration

on

the

human

body

In

agreement

with current standards for Hand-Arm

and

Whole-Body (Including Motion Sickness} mea-

surement.

The

complex relationship between

level,

frequency,

and

time,

Is

automatically tak-

en

Into account

In

the computation of

equivalent continuous vibration

level

and

expo-

sure dose. Either of these parameters, the

maximum peak vibration

level,

or the elapsed

time,

can

be

displayed at

any

time. Powered

from Internal batteries for both field

and

lab-

oratory

use,

It

Is

designed for

use

with

Uni-Gain® Accelerometers, Including the Tri-

axial Seat-Accelerometer

Type

4322

for

measurements with seated persons.

+ Bri.iel & Kjcer

•--

-

o--

In

:1

Cl

o--

I U

1-.

_I

..

0

.,_

-

,----

._.._

.,._

---,

o--

-,

,-

,-,

-o

.--,:

:,

,_,

-•

•

BrUel

&

Kjcer

.

DK-2850

NIERUM,

DENMARK·

Telephone, +

452800500

·Telex, 37316 bruka

dk

Printed

in

Denmark

by

Nairum

Offset

Instruction

Manual

Human-Response Vibration Meter Type

2512

Tv

p•

251

2

Human-II•-•

Vibration Meter

033-0659

Whole B

ody

1 -

80H,

l

xv

~tz

Comfort

Fet~Deer.

Proficiency

£)(l)OSUre

Limi

t

0,1

-0,63

Hz

Motion Sicknass

I

Z-•::uced

Comfort

s~re

Discomfort

MtJasurement

-

LP

r

esetJ

I •

D

ispla:

.

yM

od

e

Overload

E<l

,

EJq)

.

%-

---

Leq

---

Peakd

B

---

ElaPoed

Minutes

Vi

bration

level

RMS

(H

. A.

Add

20

dB)

®•

::

28V

lmA

,-------lnput------

1

(X)

2(V) 3

(Zl

1 1 3 Ref.

Seat~

0 Q

<'

--·

..

~c::~

X Y

Z~

The

2512

Is

a

single,

easy

to

operate

Instru-

ment designed for the evaluation of the effects

of vibration

on

the

human

body

In

agreement

with current standards for Hand-Arm

and

Whole-Body (Including Motion Sickness) mea-

surement.

The

complex relatlonshlp between

level, frequency,

and

time,

Is

automatically tak-

en

Into account

In

the computation of

equivalent continuous vibration

level

and

expo-

sure dose. Either of these parameters,

the

maximum peak vibration level, or the elapsed

time,

can

be

displayed at any time. Powered

from Internal batteries for both fleld and lab-

oratory

use,

It

Is

designed for

use

with

Uni-Gain® Accelerometers, Including the Trl-

axlal Seat-Accelerometer

Type

4322

for

measurements with seated persons.

+ Briiel & Kjaer

HUMAN-RESPONSE VIBRATION METER

TYPE 2512

Applicable

to

instruments from serial number 927661

April

1981

CONTENTS

1.

INTRODUCTION AND SPECIFICATIONS {PRODUCT DATA) ........................................................................... 1

2.

CONTROLS.......................................·...........................................................................................................................9

2.1. FRONT PANEL.......................................................................................................................9

Power and Input Controls....................................................................................................9

Displays and Display Control ............................................................................................ 1

O

Measurement Selection and Control................................................................................

11

2.2.

REAR PANEL .......................................................................................................................

13

3.

OPERATION...............................................................................................................................................................

17

3.1. MOUNTING...........................................................................................................................

17

3.2. POWER SUPPLY .................................................................................................................

17

Battery Check ......................................................................................................................

18

Replacement and Installation

of

Internal Batteries ........................................................

18

Power Supply ZG 0199

for

AC

Line Operation and Recharging Rechargeable

Internal Batteries .........................................................................

;.......................................

19

Recharging Batteries in situ using the Battery Charger ZG 0113................................

21

Using

an

External DC Supply............................................................................................

21

3.3. CALIBRATION ......................................................................................................................

23

Calibration using the Internal Reference Signal .............................................................

23

Calibration using the Accelerometer Calibrator Type

4291

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

24

3.4. STAND ALONE OPERATION

OF

THE INSTRUMENT....................................................

26

4.

USE

WITH

OTHER

INSTRUMENTS

...................................................................................................................... 29

4.1. USE WITH THE ALPHANUMERIC PRINTER TYPE 2312 ..............................................

29

4.2.

USE WITH THE PORTABLE LEVEL RECORDER TYPE 2306......................................

31

DC Linear Recording ..........................................................................................................33

4.3. USE WITH THE STATISTICAL NOISE LEVEL ANALYZER TYPE 4426......................

34

4.4. USE WITH THE TAPE RECORDER TYPE 7005/6..........................................................

37

Recording Data

for

Later Analysis by the 2512 .............................................................

38

Analyzing Recorded Data with the 2512..........................................................................

39

4.5. USE WITH THE TUNABLE BAND PASS FILTER TYPE

1621

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

40

5.

READING DATA FROM THE 2512 OVER THE IEC INTERFACE....................................................................

43

5.1. IEC FUNCTIONS IMPLEMENTED...................................................................................... 43

5.2. INTERFACE BUS

CONNECTIONS.............................................................................

43

5.3.

CONNECTING EXTERNAL DEVICES TO THE 2512 VIA THE IEC

INTERFACE BUS .................................................................................................................44

Manual Mode .......................................................................................................................44

Addressable Mode: Using an External Controller

to

Address the 2512

Individually............................................................................................................................46

6.

SERVICE AND REPAIR...........................................................................................................................................48

USES:

•

Measurement

of

vibratory

motion

based

on

standardised

human

response

criteria

•

Measurements

in

the

design,

development

and

inspection

of

passenger

vehicles,

tractors,

earth-

moving

equipment

etc.,

and

powered

hand-tools

for

increased

comfort

and

reduced

fatigue

•

Monitoring

human

exposure

to

vibratory

environments

•

Frequency

analysis

of

vibration

together

with

external

filters

FEATURES

(2512)

:

•

Whole-Body,

Hand-Arm

and

Motion

Sickness

measurements,

weighted

in

accordance

with

standards

and

recommendations,

with

a

single

portable

instrument

•

Digital

readout

of

percentage

of

permitted

exposure

dose,

equivalent

RMS

exposure

level (Leq ),

peak

acceleration

level

(giving

crest

factor)

and

elapsed

time

•

X-Y-Z

inputs

and

appropriate

weighting

•

Analogue

meter

aids

signal

monitoring

and

m/s

2

to

dB

conversion

•

Built-in

battery

or

external

DC

power

supply

•

Provision

for

connecting

external

filters

•

Analogue

(AC

and

DC)

output

for

tape

and

graphical

recorder

or

level

analyzer

116-81

types 251 2 and

4322

Human-Response

Vibration

Meter

and Triaxial

Seat-Accelerometer

Type

2512

~

Vibration

....

.,

~

0,1 -

0,63

Hz

Motion

Sickness

Z-His

··-

Comfort

Severe

Discomfort

Measurement

Start Stop

-

L.

Pre

se

t..../

•

Digital

data

output

via IEC

625

compatible

interface

bus

for

automatic

readout

of

fu

II

data

to

alphanumeric

printer,

calculator

etc.

FEATURES

(4322):

•

Detects

vibration

in

three

mutually

perpendicular

directions

•

Built

into

a

flexible

rubber

pad

for

comfortable

seating

•

Integral

robust

cable

The

emergence

of

standards

and rec-

ommendations

specifying

boundaries

for

human

exposure

to

mechanical

vi-

brat

ion

has

prompted

the

develop-

ment

of

the

Human-Response Vibra-

tion Meter Type

2512,

a single eas-

ily

operated

instrument

designed spe-

cially

for

mal<ing

measurements

in

accordance

with

these

standards.

The

2512

includes

comprehensive

measurement

facilities

enabling

the

evaluat

ion

of

"human

"

vibration

as

covered by

current

standardisation

,

Hand

-

Arm

and

Whole

-Body

including

Motion

Sickness. The complex

compu-

(

1--

:Vibration

a..vet

RMS

(H

. A. Add

20

dB)

Owrloed

Eq

.

Elcp

.

%--e

Leq

.__.

p-

Peak~

®•:

Elapsed

Minutes

I

..

28V

2mA

Briiel&tQ...

()i

Input

1 (X) 2(V) 3 (Z) 1 2 3 Ref.

Seat-

090

:-:,, Acce

l-

eromater

J

4322

tation

of

level.

frequency

and

time

factors is

automatically

carried

out

by

the

251

2

which

displays

either

the

exposure dose,

the

equivalent

contin-

ous

vibration

level. or

the

max. peak

vibration

level.

Its .

small

size

and

built

-

in

battery

power

supply make

the

2512

ideal

for

both

field

and

laboratory use.

·

several

vibration

pick-ups are avail-

able

including

Triaxial

Seat-Acceler

-

ometer

Type

4322

which

is specially

designed for

wh<;>le

'-body

measure

-

ments

.

Standards and Recommendations

Human-Response

Vibration

Meter

Type

2512

is designed

to

make

fre-

quency-

and

time-weighted

vibration

measurements

in

accordance

with

(1)

International

Standard ISO

2631

-

1

978,

"Guide

to

the

evaluation

of

hu-

man

exposure

to

whole-body

vibra-

tion"

. (2)

Draft

Amendment

to

ISO

2631

DAM

1

submitted

14-2-80

(3)

Revised

draft

addendum

to

ISO

2631

DAD 2

(16-9-80).

"Evaluation

of

ex-

posure

to

whole-body

z-axis vertical

vibration

in

the

frequency

range

0.1

to

0,63

Hz. (4)

Draft

International

Standard

ISO/DIS

5349.

Submitted

1

8-1-1

979,

"Principles

for

the

meas-

urement

and

the

evaluation

of

hu-

man

exposure

to

vibration

transmit-

ted

to

the

hand"

.

Numerous

national

standards

can

be

expected

to

appear

which

will

be

based

on

these

international

docu-

ments

.

Current

status

of

both

na-

~ional

and

international

standards

should

be requested

from

the

rele-

vant

national

standards

institute.

Triaxial Seat-Accelerometer Type

4322

is

dimensioned

i~ accordance

with

the

requirements

of

SAE Recom-

mended

Practice J

1013

(1973).

Human-Response

Vibration

Meter

Type

251

2

Introduction

Human-Response

Vibration

Meter

Type

251

2

is

a

dedicated,

battery

operated

instrument

for

measuring

vibratory

motion

with

respect

to

its

ability

to

cause

discomfort

or

dam-

age

to

the

human

body

. The

instru-

ment

is

conditioned

to

measure

vi-

brption

in

accordance

with

criteria

laid

down

in

several

national

and

international

standards

and

recom-

mendations.

Three

categories

of

human

vibration

which

it

measures

.

Fig.4

shows

the

filter

characteristics

graphically

. The

reference

levels, 0 dB,

for

the

curves

in Fig

.4

are a

function

of

several

factors

as specified by

the

relevant

standards

and

recommen-

dations

. These

factors

are

tabulated

in Fig .5.

Sockets are provided on

the

rear

panel (Fig .1)

for

connecting

an

exter

-

nal

filter

which

can be used to-

gether

with,

or

instead of,

the

built-

in

weighting

filters.

The 8 & K

Third-

Octave

and

Octave

Filter

Set Type

161 8

(mains

powered)

and

Tunable

Filter Type 1

621

can

thus

be

cou-

pled

directly

to

the

251

2.

Measure-

ments

with

external

filters

are

of

3

particular

interest

where

wide-band

weighted

measurements

made

with

the

251

2

show

that

the

prescribed

limits

have

been

exceeded,

but

where

it

is

possible

that

third-oc-

tave

analysis

will

reveal

levels

be-

low

these

limits

.

Filter

Set

Type

161 8

has

its

lowest

frequency

third-

octave

filter

centred

at

2 Hz

and

covers

the

whole

of

the

hand-arm

vi-

bration

measuring

range.

Battery

op-

erated

Tunable

Filter

Type 1

621,

which

has

a

23%

(~ 1/ 3 octave)

bandwidth,

covers

down

to

0,2

Hz

and

therefore

covers

the

whole-

body

(excluding

motion-sickness)

and

hand-arm

measuring

ranges

.

Where

it

is

required

to

perform

measurements

with

the

user's

own

special

weighting

filters

these

can

also

be

connected

as

external

filters

instead

of

the

251

2's

built-in

stand-

ard

filters.

The

unweighted

or

weighted

AC

vibration

signal

can

be

accessed

at

the

output

socket

for

external

filters

for

output

to

a

statistical

analyzer,

tape

recorder

or

for

one-third

octave

frequency

analysis,

to

the

Digital

Frequency

Analyzer

Type 21 31 .

Measurement

Modes

Following

the

input

circuitry

and

frequency

weighting

stages

of

the

instrument

are

the

signal

detector

and

calcuration

stages

which

com-

pute

the

signal

level-time

relation-

ship.

The

instrument

simultane-

ously

measures

the

signal

in

the

fol-

lowing

three

modes

.

Equivalent Exposure Measure-

ment. In

this

mode

the

instrument

computes

the

accumulated

vibration

dose

expressed

as a

percentage

of

the

vibration

dose

allowed

for

the

measured

time.

The

computation

is

made

in

accordance

with

the

calcu-

lation

method

prescribed

by

the

whole-body

vibration

standard

ISO

2631.

The

calculation

procedure

for

hand-arm

and

motion

sickness

equivalent

exposures

is

carried

out

in

a

similar

way.

The

filtered

vibra-

tion

signal

is

first

rectified

by

a

lo-

garithmic

root-mean-square

(RMS)

detector

which

is

interrogated

every

two

seconds

(ti

= 2). Each

two-sec-

90dB

100dB

110dB

20

15

10

5

ai

:s

0

C

0

-~

a.

-5

E

<(

a,

U::

-10

C)

C

·

;;

.c

-~

~

-15

-20

(

'<

/

Motion

Sickness

(Reduced

Comfort)

I '\

,...---....,

r\ I

//

/

'~

{ /

I

/

Motion

Sickne~

\Y

V

(Severe

Discomfort)

1

!,

I

A\

I I

';

\\

r

l\

I

I \

I

I \

vHand

-

Arm

·

~

I\

I '

\

)< \ \

\

Whole

Body\

\ \ '

~

Loog;1"d;MI la,I \

\' \ \\

Whole

Body

~

' \

Lateral / \ \

(a

x and

ay)

\ ' \

\

-25

-30

\ \ \ \

\ \ \ l

-35

O,Q2

0,

05

0,1 Hz 0,2

0,3

0,5 1 Hz 2 4

810

16

50

80100

200

500

1

kHz

2

Frequency

791073

/2

Fig.4. Response

of

frequency-weighting filters included in Type

2512.

Hand-Arm

Vibrat

ion Exposure

(ms

-2rms) (Reference Frequency 160 Hz)

Uninter-Regularly Interrupted

Expo

su

re

ti

me

during rupted Duration

of

regular ti

me

interval

WITHOUT

vibr

ation

d

ai

ly

shift

or

not

(minutes per working hour)

(8h) regularly

interrupted Up

to

10 > 10

to

20 > 20

to

30 > 30

to

40

>

40

Up

to

30 min.

40 40

-- - -

> 30 mi

n.

to

lh

32 32 ----

>

lh

to

2h

24

2~

24 32 40 40

>

2h

to

4h 16 16 16 24 32

40

> 4h to 8h 8

(xl)

8

(xl}

8

{xl)

16 {x2) 24 (x3) 32 {x4)

Whole Body

Expo

sure Exposure Fatigue Decreased Reduced

Comfort

Vibration

Ti

me

Limit

Proficiency Boundary Boundary

1

to

80

Hz

(ms

-2)

rms

(ms-2) rms

(ms

-2) rms

24h 0,28 0,14 0,044

16h 0,42 0,

21

0,067

Longitudinal axis

{a

2) 8h 0,63 0,31 0,098

{Reference Frequency 4h 1,1 0,53 0,17

4

to

8 Hz) 2,5h 1,4 0.71 0,23

Transverse

axes

{a

x and av)

lh

2,4 1,2 0,37

{Reference Frequency 2,8 Hz) 25min 3,6 1,8 0,57

16min 4,2

2,1

0,67

lm

in 5,6 2,8 0,90

Whole Body

Vibration

Exposure Time Reduced

Comfort

Boundary

Severe

Disc•.Boundary

{ms

-2)

0 1

to

0,63 Hz

{Mot

.Sickness)

{ms

-2) rms Ref. fr. 0,36 Hz rms {Ref. fr. 0,1

to

0,3 Hz)

Vertical

Motion

8h -0,25

in longitudinal 2h -0,5

(a,) a

xi

s 30 min -1,0

1

to

4 min 0,86 -

791091

/2

Fig.

5.

Absolute

RMS

acceleration amplitudes corresponding

to

the O

dB

reference level

on

the

frequency weighting curves in Fig.4. (In accordance

with

the relevant standards and rec-

ommendations and valid for one-third octave bandwidth measurements)

120

dB

130

dB

140

(dB

re.

10-6

ms-

2

)150

dB

160

dB

170

I'I ' I 1,

1 I I \ I'I

',

1 I I I I '1I ' I I I 1

,'

I I

0,0316

0,05

ms-2 0,1

0,15

0,2

0,3

0,5

ms-2

I I' I '1 I I

1'

I I I

,,I

I'

I 1,1 I I 1

1 I'

I,,,

11

'I

,,I'

I I I 1

,1

i'

I 1

1 II I 1,1 I I I

I'

I

3 4 5 ms-2

10

15

20

30

40

50

ms-

2

100

150

200

250316

1,0 1,5

2

Fig.6. Scale for conversion

of

acceleration level (dB re. 1

o-6

ms-2)

to absolute acceleration units

ms-2.

(Note: 1 g =

9,81

ms-2)

791071

4

40

N150

30

20 I

E Hand-

Arm

-Uninterrupted

1-----+--+--+--+---+----+---+-----+------½

(Reference Frequency 160 Hz)

15

C0

I

10 0

-140

Whole-Body Exposure

Limit

I

. Ref. Freq.

(az)

4

to

8

Hz

Whole-Body Fatigue

Dec

. Prof. ..

..

(ax

and

ayl

2,8

Hz

N 8

I

p

~4

-~ 3,2

a;

2

oi

8 1,5

,ct

~

1,0

a: 0,8

] 0,5

-g,

0,4

~

0,32

~

0,2

~

0,15

[

0,1

LL

0,08

~

co

:E!.

C

.g130

~

Q)

oi

0

,ct

~

120

a:

]

..c

Ol

~

110

>

0

C

Q)

:::,

[ 100

LL

Whole-Body Reduced Comfort

Motion

Sickness Reduced

Comfort

Reference Frequency 0,36

Hz

I I I I I

0,05 95

1,5-2

-3-4-5

·

6-

8

·10-15-20-25

30 40 50 min-Exposure Time

--+--~~-I

1 min. 0,1h 0,5h

lh

1,5h 2h 3 4 5 6 8

1012

16

2024

791106

Fig.7. Frequency-weighted amplitude versus

time

weighting functions built into the

2512.

The

form

of

the permissible

limit

lines shown are

as

prescribed in the relevant standards and

recommendations and are normalised

to

the reference frequencies indicated

ond

RMS level is

compared

to

the

vi-

bration

level

versus

permissible

ex-

posure

time

relationship

specified

by

the

document

defining

the

hu-

man

vibration

criteria

chosen

.

These

relationships,

which

are

shown

graphically

in

Fig.7

are pre-

programmed

into

a

digital

memory

(ROM)

built

into

the

2512.

The

me-

mory

then

provides

the

permissible

exposure

time

(

Ti)

for

the

two-sec-

ond

RMS level.

The

sum

of

the

indi-

.d I d ·

ti

vI

ua

two-secon

ratios

I:

- . x 1

00%

Tl

is

defined

as

the

"equivalent

expo-

sure"

and

by

definition

must

be

<

100%

to

be

within

the

permissi-

ble

exposure

limit

.

Continuous

sum-

mation

of

these

two-second

doses

to

obtain

the

equivalent

exposure

is

performed

by

the

dose

calculator

which

updates

the

digital

readout

accordingly

every

two

seconds. The

display

is

calibrated

to

indicate

1

00%

when

the

permissible

expo-

sure

limit

is reached.

Leq

Measurement.

Leq

(equiva-

lent

continuous

vibration

level) is a

logarithmic

function

of

the

fre-

quency-weighted

energy

mean

vibra-

tion

level averaged over

the

whole

measuring

period. It can be

consid-

ered as

the

vibration

level

which

would

have

the

same

(frequency

weighted)

vibration

energy

as

the

ac-

tual

fluctuating

vibration

signal

mea-

sured

over

the

same

period

of

time

.

In

the

251

2

the

varying level

of

the

actual

vibration

signal

is

continu-

ously

sampled,

squared,

and

"parked"

in a

digital

memory

. The

L,

eq

calculation

circuitry

continu-

ously

calculates

the

average

of

the

values

accumulated

in

the

memory

from

the

beginning

of

the

measure~

ment

period. A

corrected

averaged

level updates

the

digital

display

every

eight

seconds. The

equivalent

level

obtained

can be .expressed as

follows

:

Tf

(a

(t)

~

?dt

,o-67

0

where

Leq

is in dB re. 1

o-

6

ms-

2

and

a(t) is

frequency

weighted

accel-

eration

in

ms-

2

The

digital

memory

used

to

store

Leq

data can

accommodate

data

from

at

least a

1000

s ("' 17

min-

utes)

and

up

to

a

53

minutes

meas-

urement

period

depending

on

the

signal level. A

full

memory

is

indi-

cated by a lamp.

Whole-body

vibration

measured

over a

short

period in

the

Leq

mode

can be

entered

into

the

level-time

curves

shown

in

Fig.7,

to

find

di-

rectly

the

maximum

permissible

ex-

posure

period,

assuming

the

meas-

urement

period

to

be

representa-

tive

.

The

Leq

measurement

mode

is

useful

for

quick-look

measurements

since

the

measuring

period can be

terminated

at

will,

logically

when

the

Leq

reading

has

stabilised

at

an

approximately

steady value. Periodic

readout

and

resetting

of

the

Leq

cal-

culator

can be

performed

automati-

cally

in

conjunction

with

readout

to

the

Alphanumeric

Printer

Type

231

2,

or

other

device

connected

via

the

IEC

compatible

interface

bus.

Triaxial

measurements

are

made

by

sequentially

measuring

Leq in

the

X,

Y

and

Z

directions,

then

taking

the

square

root

.

of

the

sum

of

the

squares

of

the

three

Leq s (in

ms-

2).

This

will

yield

the

max.

weighted

Leq,

which

can

be

evalu-

ated

with

Fig.

7.

Peak

Measurement.

A peak

detec-

tor

continuously

monitors

the

fluctu-

ating

vibration

signal and

stores

the

maximum

ievel

which

has

occurred

during

the

measuring

period.

The

maximum

peak level is registered

on

the

digital

readout

in dB re.

1

o-

6

ms-

2.

It is

generally

recommended

(for

example

in

IS0

'

2631)

that

when

re-

porting

human

vibration

environ-

ments,

the

crest

factor,

that

is

the

peak value

to

rms

value

ratio

of

the

signal,

should

also be

determined

.

This is

simply

calculated,

first

con-

verting

the

peak

and

RMS levels

measured,

to

absolute

values

using

Fig.6

.

Measurement

Period. The period

during

which

the

measurement

and

calculation

circuits

are active is go-

verned

by

the

"Start"

and

"Stop"

buttons

. The elapsed

measurement

time

in

minutes

(resolution

0,

1

min

., 6

s)

may

be displayed.

Analogue

Meter

. A

small

moving

coil

meter

mounted

ori

the

front

panel

indicates

the

RMS

level

of

the

filtered

and

rectified

vibration

sig-

nal. It has a scale

calibrated

to

read

in dB re . 1o- 6 ·

ms

-2

and

in

ms

- 2 . It aids visual

monitoring

of

the

signal level and can be used

for

unit

conversion

between

the

two

scales.

When

switched

to

measure

hand-arm

vibration

,

20

dB (x 10)

should

be added

to

the

indicated

le-

vel.

Overload Indicators

Three

light

emitting

diode (LED)

lamps

mounted

adjacent

to

the

"Dis-

play

Mode"

switch

indicate

various

overload

conditions

so

that

false

measurements

can be avoided. The

Eq

. Exp . LED

lamp

lights

when

the

equivalent

exposure

"do

"

s~"

e_xceeds

9999%

. It also

indicates

when

the

5

RMS

acceleration

level is so

high

during

a

two

second dose calcula-

tion

period

that

the

maximum

per

-

missible

dose (in Fig.7),

would

be

exceeded

if

the

level

was

main

-

tained

over a 1

min

. period. In

this

case

the

overload

lamp

lights

for

about

2 s

for

each excess. Levels ex-

ceeding

the

limit

are

interpreted

as

max

. levels

but

dose

counting

con-

tinues

as

normal

.

The Leq overload LED

lights

when

the

Leq

calculator

memory

is

filled

to

capacity.

Under

worst-case

condi-

tions

this

will

occur

after

a

1000

s

(~ 17

minutes)

measurement

pe-

riod.

Where

Leq is less

than

1

35

dB

the

maximum

measurement

period

of

53

minutes

is

obtained,

after

which

the

overload

lamp

lights.

The AC

signal

level is

monitored

at

several

points

in

the

high-pass,

low-pass

and

weighting

filter

circui

-

try

by a peak overload

detector

.

Overloads are

indicated

by

the

"

Peak"

LED

lighting

for

the

duration

of

the

overload

condition.

Reference Oscillator

A

built

-in

oscillator

generates

a

16 Hz

reference

signal

which

en-

ables

the

instrument

's

operation

to

be

checked-out

. The

reference

level

is

precalibrated

according

to

the

vi-

bration

category

and

discomfort

/

danger

criterion

chosen

. A

typical

readout

is

shown

in Fig.

9.

(10

: i

:3:

1t,

ELAP

'.:;

ED TI ME

MI t·WTES• • • 000·~• 2

F'

EAK• • • • DB 1

::::

:::• 5

LEO

•••••

DE:

125.

5

E

n E

::-:

:

F'

0

'.:

;

~-

rn

-Z- FD

F'

• • \

Ci

47

810023

Fig.9.

A typical printout

from

the

Alphanum-

eric Printer Type

2312

used

to

record

data

from

the

Human

Vibration

Meter

Type

2512

The

Output

to

External

Filter,

on

the

rear

panel

of

the

251

2,

is an

AC

signal

output

which

may

be

switched

to

take

the

AC

signal

either

before

or

after

the

frequency

weighting

filters

.

This

enables

sig-

nal

amplitude

distribution

analysis

to

be

performed

together

with

the

Level

Analyzer

Type

4426,

which

continuously

samples

the

vibration

signal

and

sorts

it

into

0,

25

dB le-

vel classes.

Power

Supply

The

internal

power

supply

con-

sists

of

six

alkaline

cells

which

give

a

continuous

operating

capacity

of

18

hours

. Rechargeable

cells

, QB

0008,

can be

supplied

as

an

op-

tional

extra,

their

capacity

covers

12

hours

operation.

An

optional

bat-

tery

charger,

ZG

0113

can

fully

charge

these

cells

in

14

hours.

The

charger

also

functions

as a

mains

adaptor

as

it

provides

sufficient

power

to

run

the

instrument

(via

the

rechargeable

cells) and

charge

the

cells

simultaneously.

An

external

DC

power

supply

of

+ 6

to

+

15

V,

such

as

Power

Sup-

ply Type

2808

or

an

automobile

bat-

tery

can also be used

to

power

the

2512

.

A

28

V

power

outlet

rated

at

2

mA

is provided on

the

front

panel

specifically

for

powering

the

integ-

rally

mounted

preamplifier

of

the

high

sensitivity

Accelerometer

Type

8306

.

A

miniature

meter

on

the

front

panel

indicates

whether

the

internal

battery

or

external

power

supply

vol-

Triaxial Seat-Accelerometer Type

4322

Accelerometer

Type

4322

is

specially

designed

for

detecting

vib-

ratory

motion

in

connection

with

the

measurement

of

whole-body

vi-

bration

and

is

intended

to

be posi-

tioned

under

the

buttocks

of

a

seated

person.

It

contains

a

triaxial

pickup

able

to

detect

vibration

in

three

mutually

perpendicular

direc-

tions,

that

is,

vertically

(Z-axis)

but-

tocks

to

head,

transverse

(Y-axis)

right

to

left

side,

and

(X-axis) back

to

chest

.

The

transducer

consists

of

a se-

mi-rigid

ni

trile

rubber

disc

205

mm

("'

8,

1

")

diameter

with

a

contoured

bulge

in

its

centre

housing

a

triaxial

accelerometer

which

is in

turn

mounted

on a

stiff

75

mm

dia.

me-

tal

disc

. To

make

the

transducer

comfortable

to

sit

on,

the

rubber

disc is

only

3

mm

thick

at

its

peri-

phery

,

increasing

to

12

mm

thick

at

its

centre

and

is

flexible

so

that

it

is able

to

deform

to

follow

the

seat

contours

.

Transducer

dimensions

are

in

ac-

cordance

with

the

requirements

of

SAE

Recommended

Practice J 101 3

(1973)

.

Charge Sensitivity:

1

pC

/

ms-2

, ±2%

(-

10

pC/g)

Frequency Range:

Built-in triaxial accelerometer element:

0,

1

Hz

to

2

kHz(

+ 5%)

Complete

seat

accelerometer

on

simu-

lated seat: 0,1

Hz

to

100

Hz(+

5%)

Capacitance:

1

200

pF

including

3 m

integral

cable

Maximum

Transverse Sensitivity:

(of

each

element)

<

4%

Piezoelectric Material:

PZ

27

Configuration:

Delta

Shear®

Minimum

Leakage Resistance:

(at

20°C)

>20GO

Fig.10

. Accelerometer Type

4322

seen

from the underside

Two

1,2 m long

straps

(DH

0411)

are provided

which

can be

threaded

through

the

40

mm

wide

slots

in

the

transducer

to

hold

it

in

position

on

the

seat

during

rough

rides,

or

for

example,

to

strap

the

transducer

to

the

human

chest.

The

accelerometer

pickup

con-

tained

in

the

4322

has

three

separ-

ate

Delta

Shear®

elements

assem-

bled

in

a

common

housing.

They

are

of

the

Uni-Gain®

Type

which

Specifications

4322

Typical Temperature Transient Sensitivity:

(Measured

with

Human

-Response

Vibra-

tion

Meter

Type

2512

.

Worst

case

with

motion

sickness selected)

3

ms-2

/°

C

Materials:

Accelerometer Case:

Nickel-plated

brass

Base Disc:

Nickel-plated

brass

Moulded Cushion:

Oil

resistant

nitrile

rubber

,

hardness

-

80

IRHD

Dimensions:

tage

is

sufficient

to

power

the

251

2

satisfactorily

.

means

that

their

sens1t1v1ty has

been

adjusted

during

manufacture

to

be 1

pC/ms-2

("'

10

pC/g)

within

a 2%

tolerance.

This

feature

avoids

the

necessity

of

separate

gain

adjustment

in

each

channel

of

the

measuring

instrument

.

Signal

output

from

the

acceler-

ometer

is via

three

miniature

coax-

ial sockets

feeding

three

screened

teflon

cables

which

are

grouped

into

a

common

3 m

long

output

cable. The

output

cable is

secured

in

the

pickup

by a

bush

crimped

to

the

cable,

this

prevents

excess

ten-

sion

being

applied

to

the

three

con-

nectors

.

A

6-pin

DIN

screw-locking

plug

matching

the

input

of

the

Human-

Response

Vibration

Meter

Type

251

2

terminates

the

3 m long

out

-

put

cable.

The

bottom

plate

of

the

transdu-

cer is

fastened

with

six

screws

and

sealed

with

a

rubber

gasket. In

the

event

of

cable

damage

it is

there-

fore

possible

to

gain

access

for

re-

placement

.

Environmental Temperature:

-10

to+

70°C

(-60

to

+ 1

50°C

for

short

periods)

Accelerometer

alone

200°C

Cable:

Three

in

one,

low-noise

,

individually

shielded,

Teflon

insulated

Length: 3 m (

10

ft)

Connectors:

Accelerometer

end,

three

miniature

coaxial

plugs

Remote end, 6

DIN

screw-locking

plug

JP

0602

7

Vibration Categories Measured:

Whole-Body vibration: in accordance

with

ISO

2631

-

1978

, and

draft

amend

-

ment

1.

Also

Motion

sickness

in

accor-

dance

with

Draft

Addendum

to ISO

2631

DAD 2

(16

-

9-80)

Hand-Arm vibration: in accordance

with

Draft

International

Standard ISO/DIS

5349

,

submitted

18

-

1-1979

Inputs: (to

three

charge

amplifiers)

3

miniature

coaxial sockets on

front

panel

in

parallel

with

a

6-pin

DIN socket

on rear panel

Input Sensitivity:

Calibrated

for

accelerometer

sensitivity

1

pC

/

ms-2

Input Impedance:

>

18

GO

DC

shunt

resistance

Frequency Response:

Dependent

on

category selected. See

Fig.4

Frequency

weighting

curves have re-

sponse and accuracy as

required

by

the

various

standards

mentioned

Log.

RMS

Detector:

Frequency range:

0,

1

to

1

000

Hz

Dynamic range:

60

dB

including

crest

factor

3

Time constants: 2 s

for

whole

-body and

hand-arm

(1

25

ms

in "Preset")

10

s

for

mot

i

on

sickness

Equivalent Exposure Dose Calculator:

Calculates

equivalent

exposure based

on

Log. RMS level every

two

seconds

Range: 0

to

9999%

in

1% steps

Accuracy (expressed as a percentage

of

the

dose readout): Hand-arm ± 5% ex-

cept at step level changes (see Fig.7)

Whole body

0,

1-0,63

Hz (motion sick-

ness) ± 15% . Whole Body 1 -

80

Hz

+(4 min. x Exp. dose readout %)

o/c

-Elapsed

time

(min) 0

where

equivalent

100

% dose

time

is

10

min

. to

27

min.

or ±

15

%

where

equivalent

1

00

% dose

time

exceeds

27min

.

Leq

Calculator:

Calculates

equivalent

continuous

vibra-

tion

level according to

the

equal

energy

principle

Updates display every

eight

seconds

Capacity: at least

1000

s (

16,6

min

.)

measuring

time,

maximum

53

minutes

Range:

104

to

139,5

dB

(-

0,

16

to

9.4

ms-2)

for

whole-body

and

motion

sickness

124

to

159,5

dB

(-

1,6

to

94

ms-2)

for

hand

-

arm

Accuracy:

better

than±

0,5

dB

Crest Factor Capability:

better

than

3

(worst

case

at

max. level)

Log. Peak Detector:

Stores

Max. peak level

during

measure

-

ment

period

Specifications

251

2

Range:

100

to

146

dB

(-

0,

1

to

20

ms-2)

for

whole-body

and

motion

sickness

1

20

to

1

66

dB

(-

1

to

200

ms-2

,)

for

hand-arm

Accuracy: ± 1 dB

Digital Display:

7

segment

LED, 4

digits

Quantities Selectable:

Equivalent exposure, 1

to

9999%

resolu-

tion,

1%

Leq

100

to

159,5

dB,

resolution

typically

0,

5dB

Peak level,

100

to

166

dB,

resolution

ty-

pically 0,5 dB

Elapsed

minutes

, 0

to

999

minutes,

reso-

lution

0,

1

minutes

Analogue Meter:

Indicates Log RMS level

in

dB re 1

o-6

ms-2

and

in

ms-2

·

20

dB

must

be added

to

meter

reading

for

hand-arm

measurements

Overload Indicators:

Equivalent Exposure: LED

lamp

indi-

cates dose exceeding

9999%

or

exceed-

ing

of

2 s dose

maximum

(lights

for

- 2

s)

Leq:

LED

lamp

indicates

memory

full

or

53

minutes

exceeded

Peak: LED lamp indicates overload

in

AC

circuitry

Reference Oscillator:

16 Hz reference signal gives Leq =

120dB

(1

ms-

2)

±0,5dB

in

whole-body

and

140dB

(lOms-

2)

±0,5dB

in

hand-

arm

Not

applicable

to

motion

sickness meas-

urements

AC

Output:

BNC socket ("

Output

to Ext. 1-ilter")

Signal available

either

weighted

or

un-

weighted

Level:

200

mV

/

ms_:_

2 (at

ref

.

freq

.

in

Fig.5.)

in

whole-body

and

motion

sickness

20

mV

/

ms-2

(at

ref

. freq. in Fig.5.)

in

hand

-

arm

Output Impedance:

50

n

Min.

Load Impedance: 5 kO

DC

Offset:

300

mV

ma"-.'

DC Output:

BNC

socket

Signal

from

Log

RMS

detector

Level:

100

mV/dB.

0 V =

100

dB

in

Whole-Body

(

120

dB

in

Hand-Arm)

Min. Load Impedance: 5 kQ

Interface

Bus:

25

pin connector. Bus in accordance

wi!._h

IEC

625-1

*

Functions

Used: T3 (Addressable basic

talker

with

"talk

only"

mode); provided

with

SH

1 and AH 1

Data: Readout

of

Max

. peak and

Leq

dur-

ing

measurement

period

Equivalent Exposure

H.V. Category

and

Criterion

selected on

front

panel

Elapsed

time

Data Transmission Code: ASCII

External Filter Sockets:

Two

BNC sockets

Output

to

Ext. Filter:

As

for

AC

Output

Input from Ext. Filter: Max. signal level

6V

peak

Input impedance:

14

7 kO

in

parallel

with

100

pF

Environmental Conditions:

The

instrument

performs

within

specifica-

tions

under

the

following

conditions

:

Temperature: -

10°C

to+

55°C

Humidity: 0

to

90%

relative

humidity

non-

condensing

Magnetic: Field

strengths

up

to

100A/m

Internal Power Supply:

Six

IEC

R20

type D

cells

Operating capacity: 18

hours

continu-

·

ous

with

alkaline

cells (12

hours

with

op-

tional

NiCd rechargeable cells)

External Power Supply:

Rear panel

connection

through

7-pin

DIN

socket

Requires+

6 V

to+

15

V

DC

, 1,5 W

Power Supply Output:

28

V.

2

mA

miniature

socket,

for

Acceler

-

ometer

Type

8306

Dimensions: (excl.

feet

, knobs etc.)

Height:

133

mm

(5,2

in)

Width:

210

mm

(8,3

in)

Depth:

200

mm

(7,9

in)

(B

& K

module

cabinet

KK

0025

6/

12

of

19"

rack module)

Weight:

3,1 kg

(6,8

lb)

including

battery

Accessories Included:

6

Alkaline

Cells

1 7

DIN

plug

3 BNC

plugs

2 Spare fuses

Accessories Available:

QB

0004

JP

0703

JP

0035

VF

0050

Battery

Charger

ZG

O

11

3

6 Ni-Cd Cells QB

0008

Triaxial

Seat-Accelerometer

Type

4322

Triaxial

Accelerometer

Type

4321

Accelerometer

Types

4371,

4384

,

4370

and

8306

Mahogany

outer

cabinet

KA

0063

(sup-

plied as standard

if

251

2 B version

or

-

dered)

Carrying Case

KA

2000

Input

adaptor

for

tape recorded

signals

IEC

625-1

interface

cable

(2 m)

AO

0194

IEC

(male, slide lock) to

IEC

625-1

Interface cable

(2m)

AO

0184

Adaptor

to

convert

IEEE

instrument

to

IEC

625

-1

AO

0195

Scale for interpretation of dis-

tribution diagrams (from4426) SC 2363

Compatible

with

IEEE

Standard

488

-

1975

and

ANSI MC 1.1-

1975

2.1. FRONT PANEL

Type

2512

Human-Respon••

Vibration Meter

2.1.1. Power and Input Controls

POWER:

28 V 2 mA:

2.

CONTROLS

O,l

-0.63

Hz

Motion S,ckness

•

Z-•;:uced

Comfort

Severe

.

·-""'

•

Brilel&J(ja,r

Vilmition

level

RMS

!11

A Add

20

dB)

Power

28V

2mA

,()-i

,------Input-------,

1

(X)

2(Y)

3

(Z)

1 2 3

Ref

, I

Seat-

0 9

~

Accel-

'_r:

·_

......

.

...

_

ero7eter

xvz___;

·

Fig.

2.1.

Power and signal input controls

"Off"

-

In

this position the instrument is switched off and the contents of the

memory are erased. However, if rechargeable Nickel Cadmium cells are

being used, they can still be recharged when the switch is in this position.

"On" -Power is on in this position and the battery voltage indicator should

move from the red to the blue region, indicating that the voltage from the

batteries, or from the external power supply where used, is sufficient for

proper, reliable operation.

In

addition a number

of

the indicating light

emitting diodes will come on, corresponding to the switch positions select-.

ed during the previous measurement, and the two displays will begin to

indicate. Warm-up time depends on the mode of operation, 5 s for HAND-

ARM, 10 s for WHOLE BODY 1 - 80

Hz,

and 40 s for 0,1 - 0,63

Hz

MOTION

SICKNESS. The 2512 can be powered either from internal batteries

or

from

external supplies. See section 3.2.

28 V

(2

mA) micro-socket for supplying power to, for example, high sensi-

tivity accelerometer Type 8306.

9

INPUT SOCKETS:

INPUT CHANNEL SELECTOR:

Type

2512

Human-Re•ponse

VlbraUon

Meter

2.1.2. Displays and Display Control

DIGITAL DISPLAY:

ANALOGUE DISPLAY:

DISPLAY MODE:

10

A group

of

three microsockets

for

connecting either three separate accel-

erometers

or

the Triaxial Accelerometer Type 4321. The sockets are

connected

in

parallel with the 6-pin SEAT-ACCELEROMETER input on the

rear panel, their connections indicated by the bracketed letters (X,Y,Z) over

the respective sockets (1,2,3,).

A four-position slider switch to select the input signal to be measured and

analyzed,

or

a reference signal. Input from sockets "1

",

"2",

or

"3"

can be

selected, corresponding to the

"X",

"Y",

and

"Z"

axes

of

the SEAT ACCEL-

EROMETER input socket on the rear panel

of

the instrument. See Fig.2.6.

The

"Ref."

position connects internally generated reference signals to all

outputs including the two dis.plays. The signal is equivalent to

120

dB in the

WHOLE BODY mode and

140

dB in the HAND-ARM mode

of

operation, at

16

Hz.

It is therefore only available

in

HAND-ARM and WHOLE BODY 1 -

80

Hz

modes

of

operation, whose frequency ranges include

16

Hz.

It is not

available in the WHOLE BODY

0,

1 - 0,63

Hz

MOTION SICKNESS Mode

of

operation, because

16

Hz

is not included in its frequency rang_

e.

See section

3.3.1

for further details.

01

-

0,63

Hz

Monon s,ckness

•

Z-a;~:uced

Comfort

Severe

Discomfort

Measurement

lilil

LPreset....1

I

lOisplay

Mode

Overload

Eq.

Exp

.

%--4t

leq

ds----e

Peakds--e

Elapsed

Minut

es

Briiel&Kla,r

Vibration

level

RMS

(H

. A. Add

20

dBi

Power

@•::

28V

2mA

,-------

Input------

1

(X)

2(Y)

3

(Zi

1 2 3 Rel

•

QQ('

X y

Fig. 2.2. Display

and

display control

A four

digit

display

for

reading out the various parameters measured

or

calculated by the instrument. "Leq" and

"Peak"

values can be read out

to

a

resolution

of

0,5 dB; "Eq. Exp." to

1%;

and the elapsed time to

0,

1 minutes.

A small moving coil meter intended primarily

for

monitoring the signal level.

The scale is calibrated in dB re.

10-

6

ms-

2, and

in

ms-

2 to read RMS value

of

the measured signal.

A four position slider switch used to select the measurement parameter to

be displayed on the digital display. Three measurement parameters, each

with

an

LED overload indicator, and the elapsed time

in

minutes, can be

selected. These are:

Type

2512

Human-Raaponse

Vibration Meter

"Eq.

Exp.%"

-The Equivalent Exposure as a percentage of the vibration

dose allowed for the measurement period. The overload indicator lights

permanently if the equivalent exposure exceeds 9999% and lights for a

period of approximately two seconds each time the RMS acceleration

during a two second dose calculation period exceeds the permissible level

for the shortest exposure time considered by the standard applicable to the

selected measurement mode, or 2 minutes in the MOTION SICKNESS

mode. Dose calculation continues normally, however, with the maximum

permissible value used

in

the dose calculation.

"Leq dB" -The equivalent continuous vibration level; a logarithmic function

of the frequency-weighted energy mean vibration level averaged over the

entire measurement period. The overload LED lights when the

Leq

calcula-

tor

memory is full. This occurs between

17

and 53 minutes after the start of

measurement, depending on the level of the signal. The value is presented

in dB

re.

10-B

ms-

2.

"Peak dB" -Displays the maximum peak level which occurs during the

measurement period. The value is presented

in

dB

re.

10-B

ms-

2. The

overload LED indicator comes on if the peak frequency weighted level

exceeds the maximum allowable value at any time during its passage

through the instrument and remains lit for the duration of the overload and

at least

130

ms. Overload detection is thus carried out at a large number of

positions in the circuit.

"Elapsed Minutes" -Displays the elapsed time of the current measure-

ment with 0,1 minute

(6

s)

resolution.

O.l - 0,63

Hz

Motion Sickness

•

z-

a;

~:uced

Comfort

Severe

Discomfort

Measurement

-L

Preset-'

,------lnnur---------.

l (X)

;HY}

3 {Zl

•

00('

)(

Fig.

2.3.

Measurement selection

and

control

2.1.3. Measurement Selection and Control

The measurement selection and control switches are divided into two main fields concerned

with the selection of criteria for either whole body or hand-arm vibration, and the measurement

start/stop and interface switches as follows:

11

HAND-ARM:

Whole Body Panel

1-80 Hz range

AXIS SELECTOR:

LIMIT SELECTOR PUSHKEYS:

A set

of

five push-keys

for

selecting Hand-Arm frequency weighting filters

and time weighting functions

for

Hand-Arm measurements. Pressing any

of

these five pushkeys selects the Hand-Arm filters, whereas each individual

pushkey (labelled

"x

1

",

"x2", "x3",

"x4",

"x5")

corresponds to a certain

proportion

of

interruption

of

exposure time during the working day. Each

pushkey has a built-in LED to indicate that it has been selected.

Two groups

of

pushkeys; the upper group concerned with the ISO stan-

dardized frequency range from 1

to

80

Hz,

the lower one concerned with the_

frequency range from

0,

1 to 0,63

Hz,

which is most relevent to the predic-

tion

of

motion sickness.

Two-position slider switch to select one

of

the two different frequency

weightings which apply to the vertical and horizontal directions when mea-

suring in the whole body mode, 1 to

80

Hz.

The right (Z) position connects the frequency weighting filters aplicable to

vertical motion, and the left

(X,

Y)

position connects the frequency weighting

filters applicable

to

horizontal motion.

When

"Z"

is selected, one

of

the three LEDs to the right

of

the selected

LIMIT SELECT

OR

pushkeys lights. If

"X

Y"

is selected, the LED in the

corresponding pushkey itself lights.

A group

of

three pushkeys for selecting the whole body exposure criterion

to be used for exposure calculations by the instrument. These criteria are in

accordance with the relevant ISO Standard, ISO 2631, Guide

for

the evalua-

tion

of

human exposure to whole-body vibration.

The three selectable criteria are:

"Reduced Comfort" -Applicable to, for example, the difficulties associat-

ed with reading and writing in a vehicle.

"Fat. Deer. Proficiency" -Fatigue Decreased Proficiency, applicable to

task performance.

"Exposure Limit" -A level which should not be exceeded; the exceedance

of

which could cause permanent damage to health if the exposure were

continued throughout the working lifetime.

0,

1 -0,63 Hz MOTION SICKNESS

Z-AXIS

range

LIMIT SELECTOR PUSHKEYS:

12

Two pushkeys with integral LED indicators, for selecting the required

exposure criterion. Only a

Z-axis

weighting is available in this mode

of

operation. The two selectable criteria are:

"Severe Discomfort" as described

in

"Draft

Addendum ISO 2631/DAD2"

"Reduced Comfort" as described in earlier drafts

of

this standard.

MEASUREMENT:

INTERFACE SWITCH:

2.2. REAR PANEL

BATTERY COVER:

RELEASE SCREW:

Two pushkeys with integral LED indicators

for

starting, stopping and reset-

ting the measurement.

"Start" starts a measurement,

or

continues a measurement which was

temporarily halted using the

"Stop"

pushkey.

"Stop" stops the measurement in progress. It may be continued by press-

ing

"Start",

or

the internal registers can be cleared and a completely new

measurement can be initiated by pressing the

"Start"

and

"Stop"

pushkeys

simultaneously, the

"Preset"

position.

"Preset" is the only position which allows the measurement mode to be

altered, the HAND-ARM, LIMIT SELECTOR and AXIS SELECTOR switches

are otherwise locked in the previously selected positions. The LEDs in both

pushkeys will light when pressed simultaneously to indicate that a reset has

occured, that the instrument has been initialized, that a new measurement

mode can be selected, and that a new measurement can be begun by

pressing

"Start".

In

the

"Preset"

mode, the time constant is very short

(0,

125

s in the HAND-ARM and WHOLE BODY 1-

80

Hz

modes, and 0,6 s in

the WHOLE BODY

0,

1- 0,63

Hz

MOTION SICKNESS mode) to give a short

settling time when changing measurement mode. It may also be used when

recording on a level recorder to obtain an output with relatively short time

constant.

A single pushkey with integral LED indicator, which lights when the switch is

in the

"On"

position and the interface is connected. The instrument can

then transmit the full data list at intervals

of

2 s

or

greater.

Ext

.

Power

Supply

•Charge -

+6

Vto

l2V

+

15V

I

..

i ..

F.atteries Interface B

us

OEC)

Seat-

Accelerometer

•

O~J 8

87654321

7

I: Reset o:Accumulate

t:

Printer

0 : ca1culator

Weight

in

g Ext.

Filter Filter

Out

In

Out

Output

to

Input

from

@@

1: Ton O: Addressable

::

MSB

lDevice

A2.

Address

At

LS8

••

*CAUTION

CHARGE VOLTAGE

MUST

ONLY

BE

APPLIED

WHEN USING RECHARGEABLE BATTERIES

Fig.

2.4.

Rear Panel

A knurled screw which allows the side panel to be removed to give access

to the battery compartment

for

installation

of

new batteries. See section

3.1.

13

Switch operated

by

plug sheath

1

Ground

810237

Fig.

2.5.

Pin connections

of

the

EXT.

POWER SUPPLY

socket

looking

into the socket

or

from the soldering side

of

the plug

EXT.

POWER SUPPLY: A 7-pin

DIN

socket accepting plug JP 0703

for

connecting external power to

the instrument

for

either direct operation

or

charging rechargeable internal

cells. The pin diagram is shown in Fig.2.5. The socket may be connected

directly to the OUTPUT socket

of

the Power Supply

ZG

0199 using the cable

AQ 0035 to provide both the operating and charging voltage (when nickel-

cadmium rechargeable cells are used),

or

to a battery charger ZG 0113

which supplies sufficient power to run the instrument via the internal rechar-

geable cells, where fitted, and keep them charged. For further details on

powering the instrument, see Section

3.2.

FILTER SELECTOR:

SEAT-ACCELEROMETER

X-Axis signal

WARNING: Never attempt to recharge normal dry cells. Only nickel-

cadmium cells can be recharged.

A three-position slider switch to select various combinations

of

internal

weighting filters and external filters. With the FILTER SELECTOR in the

"Weighting Filter -Out, Ext. Filter -

In"

position and the

"Output

to Ext.

Filter" and "Input from Ext. Filter" BNC sockets connected by cable

AO 0087 i.e. short circuited, unweighted measurements can be carried out.

A 6-pin

DIN

socket for connecting the corresponding plug

(JP

0600)

of

the

Seat Accelerometer Type 4322. The connections are in parallel with the

three microplugs for the three axes on the front panel

of

the instrument. The

pin connections are shown in Fig.2.6.

Z-Axis signal

Y-.Axis signal ground

810

236

Fig.

2.6.

Pin connections

of

the SEAT-ACCELEROMETER

socket

looking

into the

socket

or

from the soldering side

of

the plug

14

BRUEL & KJAER 2512 User manual

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