BRUEL & KJAER 6302 User manual

Instruction Manual
Waveform Retriever Type 6302
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J.
03~0254
6302
A battery operated instrument used to ex-
tract periodic waveforms from noisy and
complex signals . Produces a low-frequency
duplicate of the original waveform with cor-
rect amplitude and phase relationships,
which can be plotted on a Level Recorder or
X-Y recorder. The instrument delivers sig-
nals for synchronizing the B & K Level Re-
corders Types 2306 and 2307, allowing
easy reading of phase angle throughout the
signal period. Input range is ±7 V peak, DC
to 10kHz.
+ Bri.iel & Kjmr

WAVEFORM RETRIEVER
TYPE
6302
June 1977

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS (PRODUCT DATA) .................................................... 1
2. CONTROLS ............... ... ........... . ......... . ...... . ........... .......... ..................... . .. . ........ .. ........... . ......... 5
2.1 . FRONT PANEL .. ... ........... ........ .... .............. ..... .. .. .. .. ........ .. ..... ........ .. ....... .. .. 5
Trigger Section . ........... ..... ........ ..... .. ....... ... .. .. .. ......... .. .. .. ... .. .. ........ .. ........ .. . 5
Signal Processing Section ......... .... .. .. . .......... ...... ....... ...... ................... ......... 6
2.2. REAR PANEL
..... ..... ..................... . .. ...... .. .......... ...... .. .. ........ ........ ........... .. .. 8
3. OPERATION ................. . ................................ . .. . ........ . ....... .. ....... ........................... .. ...... .. ..... 10
3.1. POWER SUPPLY .......... .. ............. ............. .......... .......... .. ....... .. .. ... .. .... ...... 10
Plug-in Power Pack ....... .. .. .. ........ . .. .. ....... .. ......... . .. ......... . .. .. ..... .. ........ .. .. .. 10
External
DC Supply ........ .. .... ........ ...... .. ............. .. .. .. .. .. ...... .......... ......... .. ... 11
Plug-in Power Supply Type 2808 .. .. ...... .. ...... .... .. .. .. .. ........... .. .. ........ .. .. .. .. .. 12
Battery Charger ZG O 11 3 .............. ....... ............ .. .... ............ .. .... .......... .. .. . .. 13
3.2. SELECTION OF RECORDING PARAMETERS
.. .... ...... ......... .... .. .. ....... ........ .... 13
Trigger Signal ........ .. . .. ................. . .. .. ......... ... .. . ......... ..... ....... ... .. ..... .. ....... 14
Sweep Period and Filter Bandwidth .. .. ......... ................ .... .. ........... .. .. .... .. .... 14
3.3. OPERATION WITH LEVEL RECORDER TYPE 2306 .. .. .... .. .. ..... .. ...... ... .. .. .. ...... 15
System Connection .. .. .. ....... . ....... . .. ..... .. ....... ...... ... .. ...... .... .. ... .. ................. 17
Adjustment and Calibration .. ........................ .. ................ ....... .. .. . .. ....... .. .... 17
Recording . .. ....... .. .. ........ .. .. ... .. .. .. .. .. .. ..... .. .. .. . .. . .. .. ... ..... .. .......... ..... .. . ...... .. 18
3.4. OPERATION WITH LEVEL RECORDER TYPE 2307 .. .. ........ ... .. ....... ... ...... .. ..... 19
Linear Recording ...... .. ..... .. ... .. .... .. .. ..... .. .. .. .. .. .. ....... ... .. .. .. ........ .. .. .... ......... 19
Polar Recording
...... . .................... .. . .. ...... .. .. .. ...... .......... ... .. ..... ....... ........... 22
3.5. OPERATION WITH AN X-Y RECORDER .. .. ... .. .. .. .......... ...... . ...... .. ... ........ .. .... 23
4. SIGNAL PROCESSING IN THE 6302 ..... ....... . ............................... .. .............. . ...... . .. .. ....... ..... 24
4.1 . SPECTRUM OF THE OUTPUT SIGNAL ....... .. ...... . .................... .. .. .. ............. .. 24
4.2 . NOISE FILTERING BY THE 6302 ....... .. .. .. .. .. .. ......................... .......... ........ .. 25

FEATURES:
•
Input frequency range DC
to 10 kHz
• Sweep period up to 999
seconds
• Input dynamic range Oto
± 7,5 V Peak
• Two separate channels
• 1° angular resolution
• Ability to start a scan at
any point in the cycle
•
Extern aI or i nterna I
triggering on 50 mV to
20 V p-p signals
• Triggering on positive or
negative slopes
• Five
low-pass filter limits
to exclude unwanted
frequencies
• Outputs and
synchronisation controls
matched for B & K Level
Recorders
•
Warning lamps for lock-on
failure, power on, input
overload and scanning
• Battery or line operation
USES:
(With suitable Chart
Recorders)
•
Extracting the basic
periodic waveform from
complex inputs
• In noise and vibration
analysis
• To establish the
"Signature" for On-
Condition Maintenance
• Prototype and project
testing, and in quality
control
• For maintenance and
repair inspection for failure
identification
• As a teaching aid
•
As a general purpose
waveform plotter
16 - 255
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The Waveform Retriever Type
6302 is used to educe a periodic
signal from noisy or complex sig-
nals composed of many frequency
components . The extracted wave-
form can be displayed on a storage
oscilloscope for monitoring, and
more importantly a permanent re-
cord can be plotted on a level recor-
der as in Fig. 1, or an X-Y Recorder
so
that a thorough analysis of the
waveform can be made . This instru-
ment enables the designer, develop-
ment engineer, quality controller,
maintenance specialist, or any
other engineer in the mechanical,
electrical, or acoustical fields to per-
form accurate waveform analysis
both in the laboratory and under
field conditions .
The design and development
engineer, or the maintenance
engineer can pass the conditioned
signal from a vibration transducer
through the Type 6302 and obtain
a cleaned waveform for examina-
tion . The vibration or sound wave-
form of a new fan or electric motor
can be plotted as in Fig. 2, and then
after some time in service, or in the
event of a suspected fault, the wave-
form can be plotted again. A deterio-
ration in condition, and in many
cases, the actual cause of a fault -
an
unbalanced fan blade, damaged
gear tooth, or tight point in a bear-
ing - will be revealed as a differ-
ence between the new chart and
the original .
type 6302
Waveform Retriever
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In quality control or prototype test-
ing of more complex machinery, a
gear box for example, when a suit-
able triggering signal is available
from each shaft, it will be possible
to "inspect" the vibration wave-
forms produced by gear wheels ro-
tating at different speeds in the box.
This type of measurement gives an
indication of eccentricity, imbal-
ance, or the quality of tooth mesh-
1ng, . and positively identifies possi-
ble
sources of future failure, like
worn or damaged teeth .
Two separate inputs can be ac-
cepted
simultaneously so that the
variations in phase and amplitude
between them can be compared .
This facility gives a useful method
for a designer to determine improve-
ments, or for a maintenance
engineer to estimate deterioration .
The
plotted waveform from a pro-
duct or machine can become part of
its "signature" used in On-Condi-
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Signal Received ===---===after Processing
OP 0102
761142
Fig.1 . Before and after signal processing

tion Maintenance. Similar products
from different manufacturers can be
compared before purchase by qual -
ity control or buying departments .
Two separate but related tests can
be
run simultaneously to save time.
The Waveform Retriever can also
function as a general purpose wave -
form plotter for straight - forward vi-
bration , noise , and electrical sig-
nals . Frequency transformations
can be made where a high fre -
quency input is plotted out at a
lower frequency, or the Retriever
can be used to plot out an oscillo -
scope
display for record purposes ,
and as a
teaching aid. The resulting
curve on the chart is several times
larger than that obtainable from pho -
tographic recorders .
Principle of Operation
The basic principle on which the
Waveform Retriever operates is
rather akin to that of the strobo -
scope, except
that an electronic
sampling action replaces the lamp
flash to isolate in time the required
portion of the signal under analys is.
As shown in Fig.3 where a no isy
signal is composed of a sine - wave
plus noise , correct adjustment of
the sweep period so that samples
are taken at fractionally longer inter-
vals than the main signal period, en-
ables the sample to be taken at a
progressively later point in each cy-
cle. It
will be seen that the sam -
pling points describe a sine-wave
with the same amplitude as the orig-
inal , but with greatly reduced fre -
quency . In practice this reduced fre -
quency is low enough to be plotted
out by a chart recorder .
In
an internal generator , a signal
is produced with periodic time T,
which can be set to values between
1 second and 999 seconds by the
Input Signal, Noise on Sinewa ve
Fig.3. The sampling process
2
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P otentio met er Ran ge ._ dB Recti fi er ·- - Low er Lim Fre! =- -Hz Wr Sp ee d :_ mm / sec Pap e rSp eed :- mm / sec .
Co pe nh agen Rotor. •
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M easuring Object : 40
Tangential Fan wi th
One Blade Gap Obstructed
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---- 20
Rec. No .: __
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Sign .: __ _
33 47 :
T ime Const. ·
W eigh t. N etw .: _
~:= Gap Obstructed Here Tangential Fan,
Normal Running
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Fig.2. The vibration waveform obtained from a tangential fan
Sweep Period controls on the fore
panel. During time T, a counting cir -
cuit counts digitally up to 360 to
yield a quantification (= resolution)
of 1°.
The trigger signal controls a simi -
lar gen e rator , wher e th e period of
the trigger signal is divided into
360 steps which are also counted
up.
A
digital comparator c ompares
the two signals , and emits a signal
ea ch ti me th e count levels coincid e.
This impulse causes a sample of
the input signal to be taken during
an APERTURE of 1 °. The sampling
frequency f5 is a fraction (~f) differ -
ent from the trigger frequency ft · In
fact
fs = ft - td
and ~f = _!_
T
which is the slow motion.
An important contribution to sig-
nal
averaging and noise elimination
is made by the built-in Output Fil-
Ampl it ude
Low P as s Filters
Line Sp ectrum
Convolved
to Origin
Noise Excluded
Line Sp ectrum
of Sinewave
Noi se Spe ctrum
Frequency
761145
Fig.4. The low pass filter
ters in both channels . They are sets
of low pass filters with varying cut -
off frequencies . If the signal shown
in a time domain in Fig.3 is trans -
posed
to a frequency domain, the re-
sult is the spectrum shown in Fig.4 .
Sampling the i nput signal at a fre -
quency very near its own results in
a slowly varying DC output from the
Type 6302 . The line spectrum be-
ing
measured has been convolved
to near the origin of the spectrum .
The low pass filter can also be
considered as a range of narrow
band filters, one at each harmonic
of the trigger (= sampling) fre-
quency. If several harmonics of the
original signal are present, as in
Fig. 5, it will be seen that they can
be
excluded from the output if a nar -
row pass band (low cut - off fre-
quency) is selected . When the BT
product of bandwidth (i .e. cut-off fre -
quency) and sweep period is made
large enough, harmonics can be in -
cluded in the output waveform . This
yields useful information on the har -
monic content, showing such fea-
tures as vibration waveforms for in -
dividual gear teeth, bearing rollers ,
fan blades , etc .
Line Sp ec t ra of Harmonics
.,__ __ _ - Signal Frequency
76 1147
Fig.6 . Use of the narrow band filters

Description
A block diagram for the Wave-
form Retriever is shown in Fig.6.
while the rear panel of the instru-
ment appears in Fig.7.
Input/Output Channels
External
Trigger Trigger
Pream -
plifier
Ext .
Ch .A. Mode
Selector
Front
Panel
Controls
DC Ramp Output
Recorder Control
Synchronisation
The two parallel channels are i-
dentical except for the Offset in Chan -
nel A (to simplify adjustment with
Level Recorders) and the ability to
use the signal in Channel A as a
trigger source. Input signals with vir-
tually any waveform, and levels up
to ± 7, 5 V peak can be accepted in
the frequency range from DC up to
10 kHz. The Signal Overload lamp
lights to warn of input overloading
of either of the Buffer Amplifiers.
f - !::,.f '
Offset
Butter
Amplifier
Buffer
Amplifier
Sample
&
Hold
Sample
&
Hold
Low Pass
Filter
Output A
-@
Output B
76 1144
The main component in each
Channel is the Sample and Hold cir-
cuit which takes a sample of the in-
stantaneous value of the incoming
signal at regular intervals .
Fig.6 . The block diagram of the Type 6302
Each channel contains a variable
Low Pass Filter to exclude frequen -
cies away from the immediate vicin-
ity of the frequency of interest (and
its harmonics) from being exam -
ined.
Cut-off frequencies are adjus-
table to 10, 3, 1, 0,3, and 0, 1 Hz,
plus a "Linear" setting. The filtered
signal is fed via the Signal Output
terminal to a Level Recorder or
X-Y Recorder for plotting .
Triggering
The signal in Channel A can be
employed as a frequency source for
synchronisation of the sampling
function. Alternatively a signal from
50 mV to 20 V peak- to-peak with
frequency in the range 1 Hz to
10 kHz can be applied to the Exter-
nal
Trigger Input terminal. The exter-
nal triggering circuit is equipped
with Sensitivity and Offset controls
allowing adjustment for optimum
triggering conditions . A double co-
axial BNC
socket is provided on the
rear panel to enable the B & K
Photoelectric Tachometer Probe
MM 001 2 to supply the triggering
signal.
Triggering can be accomplished
on positive or negative slopes of the
chosen signal. The trigger interval
is automatically phase locked on to
the trigger signal, taking a mini-
mum of ten cycles of the triggering
signal - typically about 2 seconds.
Failure to lock-on is indicated by the
Lock Error warning lamp .
Mode Selector
The front panel controls, acting
via the Mode Selector, enable the
length of the sweep period to be var-
ied
between 1 second (for low fre-
quencies or very quick, rough, plot-
ting) and 999 seconds (for maxi-
mum definition). Adjustment is
made by setting the "Sweep Pe-
riod" thumb wheels to the required
value .
Similarly it is possible to preset
the initial phase angle from which
the sweep commences to angles be-
tween 0° and 999° , using three
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Fig. 7. A view of the rear panel of the Type 6302
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thumb wheels, so that the resultant
plotted waveform can begin at any
angle in the cycle.
Setting "Reset" on the Sweep
switches makes the sampling fre-
quency exactly the same as that of
the triggering signal. It selects out-
put f from the Mode Selector so
that samples are taken at the same
phase angle for all sampling inter-
vals, and the sweep remains station-
ary. This position also resets the DC
ramp used for controlling the paper
transport of the Level Recorder Type
2307 or an X-Y Recorder.
Selection of "Operate" connects
the f-td output from the Mode Se-
lector to the Sample and Hold cir-
cuit . Sampling now occurs 1° later
with each sampling interval, and
the sweep scans through the wave-
form of the signal being examined .
Sweep in operation is indicated by a
lamp lighting. The f-M output is
available from a terminal on the
rear panel of the instrument as a
series of 2 µs pulses 5 V in level.
The f-td output is used to trigger ad-
ditional external instrumentation,
an oscilloscope for example.
The sweep can be stopped so that
any point in the cycle can be in-
spected closely by selecting "Stop" .
The other Sweep switch gives a
choice of "Continuous" scanning,
or sweeping through a "Single" cy-
cle
of the waveform .
3

Recording
Full frequency synchronisation
and signal output facilities are avail-
able
for use with Level Recorders
and X-Y Recorders.
Synchronisation pulses are emit -
ted
from the Recorder Control Syn-
chronisation terminal on the rear
panel
to control the stepping motor
in a Level Recorder Type 2306 .
Pulse
timing can be switched to
give 1 °, 3°, or 10° per millimeter
of chart paper.
There is an
internal DC ramp cir-
cuit synchronised with the angle
sweep which can control the paper
transport of the Level Recorder Type
2307 and the X-axis of X-Y Recor-
ders. The
ramp rises at a rate of
0,03 V per degree from 0 V to 11 V
Signal Input A and B:
0 to ± 7,5 V p ea k (max slew rate
0.4 V/ µs)
Overload
warning lamp operates on both
channels
Signal Frequency Range:
DC to 10 kHz
Signal Input Impedance:
50k0
Signal Gain:
OdB ± 0, 5dB
Offset Error:
±5mV
Signal Output Impedance:
1 kOl l 100nF
Self-induced Noise at Outputs A and B:
Approximately 10 mV peak-to-peak
low Pass Filter Bandwidths:
10, 3, 1, 0,3, 0, 1 Hz and Linear
Slope: 12 dB/ oct
Trigger Input:
50 mV to 20 V peak- to -peak
Trigger Frequency Range:
1 Hz to 10 kHz
Trigger Input Impedance:
200k0
Triggering:
External signal or Channel A signal
Positive
or negative slopes
Variable Sensitivity and Offset
Stabilisation Time for Phase lock:
Minimum approximately 10 cycles of
Trigger Signal
Lock Error lamp indicates lock-on failure
for 360° , with a linearity of± 1° .
The
output signals to the recor -
ders meet the same requirements
as the input signals to the instru -
ment.
Power Supplies
It is possible to power the Wave -
form Retriever from several differ-
ent sources . In its standard configu -
ration, as supplied, power is derived
from a plug-in Battery Box ZG 0146
that contains six 1,5 V standard
"D" cells (IEC type R 20) . Power
consumption is
400 mA, and the
approximately
lifetime with
standard batteries is approximately
5 hours. For a 2 to 3 times longer
lifetime, while maintaining portabil -
ity,
the cells in the Battery box can
be replaced by
alkaline batteries .
Specifications 6302
Time for One Sweep Period:
0 to 999 s
Aperture Time :
Trigger Peri
od / 360 , minimum 2 µs
Angular Resolution:
10
Angular Measuring Range (Initial Phase
Angle) :
1 to 999 °, repeating for each 360 °
Phase Noise:
Max. ±
2° , Typical ± 1°
Sweep Modes:
Continuous or Single Scan
Lamp
lights for sweep in operation
f-Af Output:
0 to 5 V pulses w i th 2 µs pulse length
Recorder Synchronisation:
2306: Motor control pulses to give 1 °,
3° , and 10° per mm paper transport
2307: DC ramp O to 11 V with linearity
± 0,4%
Power Supply:
Any of the following
1) 6 x 1,5 V Batteries, IEC R 20 , " D"
cells carried
internally in a Battery
Box ZG 0146
2) 6 x 1 ,2 V rechargeable (NiCd) cells
3)
Line voltages between 100 V and
240 V, 50 to 400 Hz with plug-in
Power Supply Type 2808
4) External DC supply from 6 to 12V ,
400 mA applied via the External
Power socket
Power Consumption:
Approximately 3 W ( 400 mA at 7,5 V)
Alternatively rechargeable nickel-
cadmium accumulators can be in -
stalled, they can be recharged by a
Power Supply Type 2808 or by a
Battery Charger ZG 011 3.
The
Battery Box can be replaced
by
the Power Supply Type 2808
which can be fitted into the battery
compartment or used externally, al-
lowing operation from line voltages
between 1 00 V and 240 V, 50 to
400 Hz. There is sufficient capacity
in the Type 2808 to power the in-
strument and recharge batteries si-
multaneously .
Power can also be obtained from
an external power supply of 6 to
12 V DC .
Battery life:
App rox. 15 hours w ith Al ka line ba tt er-
ies
Instrument Environment:
Operating Temperature Range: - 10°C
to + 50 °C (+ 14°F to + 1 22 ° F) gives no
effect
Storage Temperature (Batteries rem-
oved):
-20°C to + 50 °C (- 4°F to
+ 122 ° F)
Permitted Humidity Range: The i nstru -
ment is affected less than ± 0 ,5 dB be-
tween O and 90 % relative humidity , pro-
vided
there is no condensation
Dimensions:
Height:
133 mm (5,25 in)
Width: 430 mm (16 ,9 in)
Depth: 200 mm (7 ,9 in)
Cabinet:
Supplied as model A (light - weight metal
cabinet), B (model A in a
mahogany cab-
inet), or C (as A
but with flanges for
standard 19" rack mounting)
Weight:
4,5 kg (10 lb)
Accessories Included :
Battery Box ZG 0146
6 Batteries IEC R 20 , "D" ce lls. OB
0020
Co ax ial BNC plug JP 0035
Coaxial B & K plug JP 0101
8-pin DIN plug JP 0802
7-pin DIN plug JP 0703
Accessories Available:
Photoelectric Tachometer Probe MM
0012
Magn etic T ra ns du ce r MM 0002

2. CONTROLS
2.1. FRONT PANEL
Trigger
Lock Trigger
Sensitivity
Error Offset
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Ext . Trigger Trigger
Input Slope
770144
Trigger Trigger
Source
Range
Fig .2. 1. Trigger section controls of the 6302
2.1 .1. Trigger Section
Three toggle switches are grouped under the general label TRIGGER. They are:
SOURCE:
SLOPE:
RANGE:
Selects the control signal for the trigger section to be either a signal
applied to the EXT. TRIGGER INPUT, ("Ext." position), or the signal in
channel A, ("Ch .A" position) .
Selects positive or negative trigger slope.
Selects the frequency range of the trigger section as function of the
fundamental frequency of the trigger signal . The ranges are "1 Hz -
200 Hz" and "50 Hz -10 kHz".
The other controls of the trigger section are:
EXT. TRIGGER INPUT:
TRIGGER SENSITIVITY:
TRIGGER OFFSET:
8 & K coaxial socket for connection of an external trigger signal. Input
impedance is 200 kO. The trigger signal should be in the range 50 mV
to 20 V peak - to - peak, 1 Hz to 10 kHz. The socket accepts the stand-
ard 8 & K plug JP 0101.
Potentiometer for adjusting the gain of the trigger section . Adjustment
range is approx. + 40 to -20 dB.
Potentiometer for adjusting the offset in the trigger channel . The offset
5

LOCK ERROR:
2.2. Signal Processing Section
Signal
Overload
voltage is added after the amplifier controlled by the TRIGGER SENSI-
TIVITY
potentiometer. Offset range is approx. ± 6 V.
LED indicator which lights when the phase lock loop of the 6302 is
not locked, showing that the instrument is not synchronized with the
trigger signal.
Offset
Signal
Input A Lowpass Filters
Recorder Initial Phase
X-Scale Angle Sweep Period
Signal
Output A
-
·-
=-----Operate LED
t-------Sweep
Output A
Supply
Voltage
770143
Fig .2 _2. Controls of the signal processing section of the 6302
SIGNAL INPUT A: B & K coaxial socket for connection of the input signal to channel A . In-
put impedance is 50 kO. The signal should be in the range + 7,5 V
peak.
Frequency range: DC to 10 kHz. Accepts plug JP 0101 .
OFFSET:
Screwdriver operated potentiometer for applying a DC offset to channel
A, when the 6302 is connected to a recording device without offset fa-
cility, such as the B & K Level Recorder Type 2307. When turned fully
anticlockwise until a "click" is heard, ("Off' position), the potentiome-
ter is by-passed. The maximum offset voltage, (fully clockwise posi-
tion), is approx . + 7 V.
SIGNAL OVERLOAD: LED · indicator which lights when the voltage in either signal channel
exceeds± 7,5 V peak.
LOWPASS FILTEAS: Two rows of push-buttons for selection of the output low-pass filter in
both channels. The filters are 2-pole Chebyshev filters, with a 3 dB
bandwidth of 0,1 - 0,3 - 1 - 3 and 10Hz . A "Lin ." position is al~o
provided.
SIGNAL OUTPUT A:
INITIAL PHASE ANGLE:
6
B & K
coaxial socket. Delivers the output signal from channel A_ Out-
put impedance is 1 kO / / 1 00 nF. Max. output voltage ± 7, 5 V peak. Ac-
cepts the standard B & K plug JP 0101.
Thumb wheel switch for selection of the initial phase angle of a single
sweep . Although any value between 0° and 999°, in steps of 1 °, may
be selected, the 6302 automatically subtracts the required multiple of
360° if a value higher than 359° is entered.

RECORDER X-SCALE:
SWEEP PERIOD:
SWEEP:
SUPPLY
VOLTAGE :
OUTPUT A:
Three-position toggle switch for selection of the scaling factor of the
paper throw on B & K Level Recorder Type 2306 . Factors of "1 ", "3"
and "1 O" deg.Imm may be selected, corresponding to recording
lengths of 360, 120, and 36 mm, respectively, for a complete period
of the analyzed signal.
Thumb wheel switch for selection of the time taken by the 6302 to
reproduce one period of the trigger signal. Sweep periods from "1" to
"999"s may be selected. The reciprocal of the sweep period, M (Hz),
is
the difference between the trigger frequency, ft , and the sampling
frequency, f5, (fs = ft - ~f).
Two toggle switches for selection of the sweep mode.
The left-hand switch has three positions:
"Reset": sampling is locked on the point in the period corresponding to
the INITIAL PHASE ANGLE selected.
"Operate" : the 6302 sweeps through the signal period at the rate se-
lected by the SWEEP PERIOD selector. The OPERATE indicator (LED)
lights for as long as the scan proceeds. In the "Single" SWEEP mode,
the sweep stops when the INITIAL PHASE ANGLE is reached, and the
OPERATE indicator is extinguished. . The sweep is continuous in the
"Cont." SWEEP mode .
"Stop": the sweep is stopped at the phase angle reached when switch-
ing from "Operate" to "Stop". Switching back to "Operate" resumes
the sweep from that phase angle .
The right-hand SWEEP switch has two positions :
"Cont . ": the 6302 sweeps continuously in the "Operate" mode . The
sweep can be stopped at any point by switching the left - hand SWEEP
switch to "Stop". If this switch is set to "Reset", the sweep is stopped
and the phase angle is reset to the INITIAL PHASE ANGLE .
"Single": the 6302 sweeps one period of the trigger signal until the IN-
ITIAL PHASE
ANGLE is reached . To perform a new sweep , set the left-
hand SWEEP switch to "Reset" and back to "Operate" . If this switch
is set to "Stop" during a sweep, the sweep stops at the actual phase
angle . Switching back to "Operate" resumes the sweep, which is
stopped
when reaching the INITIAL PHASE ANGLE.
Note: if the setting of the INITIAL PHASE ANGLE selector is changed
during a single sweep, the sweep will not stop at the new INITIAL
PHASE
ANGLE, but at whichever angle was dialled in when switching
from "Reset" to "Operate".
If the needle deflects over the blue area when the instrument is
switched on, the supply voltage is sufficient. For details on power sup -
ply, see
section 3.1.
Four-position rotary switch:
"Power Off": the instrument is disconnected from the power supply .
7

2.2. REAR PANEL
Ext . Power
Supply
Recorder
Control
EXT. POWER SUPPLY:
f- L', f
"Ch.A": the signal processed in channel A is delivered at SIGNAL OUT-
PUT
A.
"Ref. 0, 1 V" : a 0, 1 V DC voltage is delivered at SIGNAL OUTPUT A for
calibration purposes.
"Ref. 1 V": a 1 V DC voltage is delivered at SIGNAL OUTPUT A for cali-
bration purposes .
Note: if an offset voltage is applied in channel A using the OFFSET
potetiometer, the reference voltages selected in the "Ref. 0, 1 V" or
"Ref. 1 V" positions are added to the DC offset.
A Output
B Output
(' ~AGtV0LfA<,f;Mt)$1()Hl,Y
ltt:O<Al'IT£t.l!ll:ftll :!I
Power Supply
B Input
A Input
Fig. 2. 3. Rear panel of the 6302
Ext . Trigger
Input
770142
A 7-pin DIN socket for connection of an external DC power supply for
powering and/ or recharging internal rechargeable batteries. Accepts
plug JP 0703 . Pin connections are given in Fig.2.4. For details on
power supply, see section 3. 1.
External Power
Charge
Input
+ 12 V DC
External Power
Input OV
External Power
-- Drive
Input
+ 6 to
+ 12 V DC
750303
Fig.2.4. EXT. POWER SUPPLY socket of the 6302
RECORDER CONTROL:
8
Caution: Do not attempt to recharge normal dry cells, such as sup-
plied with the 6302.
8-pin DIN socket accepting plug JP 0802. Pin connections are given in
Fig. 2.5.
Pin "2" is ground .

f - M :
B OUTPUT:
A OUTPUT:
POWER SUPPLY:
B INPUT:
AINPUT:
EXT. TRIGGER INPUT:
DC Ramp
Ground
Control
Pu l ses
for 2306
770140
Fig. 2. 5. RECORDER CONTROL socket of the 6302
Pin "7" delivers control pulses for the B & K Level Recorder Type
2306 . See section 3.3.
Pin "6" delivers a DC ramp to control an X-Y recorder or a Level Recor-
der Type 2307 in its X-mode. When the left-hand SWEEP switch is set
to "Reset", the ramp voltage is 0V. On switching to "Operate", the
voltage is proportional to the difference between the instantaneous
phase angle and the INITIAL PHASE ANGLE . The maximum (approx.
11 V) is reached at the end of one sweep. In the "Single" SWEEP
mode, the voltage remains at this value until the SWEEP switch is set
to "Reset", when the ramp is reset to 0 V. In the "Continuous"
SWEEP mode, the ramp is reset to 0 V each time the INITIAL PHASE
ANGLE is reached .
Pin
"4": may be used to control the "pen down" function of a graphic
recorder . The pin is grounded in the SWEEP "Operate" or "Stop"
mode , whereas the level is high in the "Reset" mode.
BNC socket delivering 0 to 5 V pulses at the sampling frequency (f
5 =
ft - M) . Pulse duration is 2µs. Accepts plug JP 0035.
BNC socket delivering the output signal from channel B. Note that the
DC offset and calibration voltages are not available in channel B.
Max . output voltage ±7,5V peak. Output impedance 1 kO // 100nF .
Accepts plug JP 0035 .
BNC
socket connected in parallel to the SIGNAL OUTPUT A socket on
the front panel. Accepts plug JP 003 5.
On delivery, the power supply compartment is fitted with the plug-in
Battery Box ZG 0146 . 6 alkaline cells QB 0004 are provided. The
cells may be replaced by rechargeable nickel-cadmium cells QB 0008 .
For
mains operation, the plug-in Power Supply Type 2808 may be in-
serted instead of the Battery Box. See section 3.1.
BNC socket for connection of the input signal to channel B. Input im-
pedance 50kO . The input voltage should be in the range ± 7, 5V peak.
Accepts plug JP 0035.
BNC socket connected in parallel to the SIGNAL INPUT A socket on the
front panel. Accepts plug JP 0035 .
Double coaxial BNC socket in parallel to the EXT. TRIGGER INPUT
socket on the front panel . The inner shield delivers the DC supply vol-
tage for the B & K Photoelectric Transducer MM 0012.
Accepts plug JP 0035 or JP 031 5 (double shield type).
9

3. OPERATION
3.1. POWER SUPPLY
The 6302 is designed for battery as well as mains operation, (in conjunction with the
Power Supply Type 2808). Battery operation is obtained using the plug-in Power Pack
provided, or from external battery or other DC source. The Power Pack consists of a Bat-
tery Box ZG 0146 containing six alkaline cells QB 0004. Rechargeable Ni-Cd cells QB
0008 are available as accessories on separate order, as are spare Battery Boxes.
Power Packs may be recharged, (DO NOT TRY TO RECHARGE NON-RECHARGEABLE
CELLS),
using a Power Supply Type 2808, a Battery Charger ZG 0113, or alternatively
an external battery or DC source .
3.1.1. Plug-in Power Pack
Fitting of Cells
10
1. Using a widebladed screwdriver, remove the Power Pack and release the lid of the
Battery Box by turning the screw head fastenings indicated in Fig.3.1.
Fig. 3. 1. Cell replacement in the plug-in Power Pack

2. If necessary, remove the old cells .
3. Load six
new cells (QB 0004 or QB 0008) into the Battery Box, as shown in
Fig .3.1. The
proper insertion direction is indicated in each of the two compartments
of the Box.
WARNING: THERE IS POSSIBILITY OF EXPLOSION IF ANY ATTEMPT IS MADE TO RE -
CHARGE CELLS
THAT HAVE BEEN FITTED WITH THEIR POLES REVERSED.
4. Replace
the lid and lock it onto the Battery Box.
5.
Insert the Power Pack in the POWER SUPPLY compartment of the 6302 . Push the
Power Pack against the pole contacts and lock it using the center screw on the Bat-
tery Box.
Replacement of Cells
Insufficient supply capacity is indicated by the needle of the SUPPLY VOLTAGE meter
deflecting over · the red area. In this case, dry cells should be replaced or Ni- Cd cells
should be recharged. Alkaline cells give approx. 15 hours of continuous operation (stand-
ard dry cells would give approx. 5 hours continuous operation). The rechargeable Ni-Cd
cells recommended are SAFT VOL TA BLOCK Type VR 4D which have a voltage and
charge rating of 1, 2 V and 4 Ah respectively. (Other rechargeable cells with similar speci-
fications may be used). When fully charged, they give approx. 8 hours of continuous op-
eration (with the 6302). SAFT, the cell manufacturers, specify that with normal use the
cells have a minimum of 300 charge cycles. These cells are normally charged in 14
hours. The need for replacement is indicated by the cells failing to reach a fupy charged
condition after having been left on charge for 14 hours or more.
3.1.2. External DC Supply
To power the 6302 from an external battery or DC supply, or to recharge its plug-in
Power Pack, the power input to the Waveform Retriever is via its EXT. POWER SUPPLY
socket (rear panel). See
Fig.2.4 for pin connections .
When a DIN plug JP 0703 is connected to the EXT. POWER SUPPLY socket the internal
Power Pack is disconnected from the supply circuitry. Hence, if only a charge voltage is
applied to the socket, operation of the 6302 (while recharging) is not possible unless
special measures are taken . See section 3.1 .4.
When a high , capacity battery (such as a car battery) is connected to the 6302, the re-
quired plug must first be inserted in the EXT. POWER SUPPLY of the 6302 before con-
necting the power source to the other end of the cable.
Recharging the plug - in Power Pack
For recharging, the plug -in Power Pack need not be removed from the Waveform Retri-
ever as the 6302 has a charging unit built in. This is powered by connecting the positive
line of an external 12 V DC supply to pin 3 of the EXT. POWER SUPPLY socket and the
negative line to pin 2. For a totally discharged Power Pack, the charge time is approxi-
mately 14 hours .
11

Powering the 6302
To power the 6302 from an external supply, there is still no need to remove the plug-in
Power Pack. The positive line of an external DC supply of + 6 to + 12 V is connected to
pin 1 of the EXT. POWER SUPPLY socket, and the negative line is connected to pin 2.
If an external 12 V DC supply is used to power the 6302, then the plug-in Power Pack
may be charged at the same time, by connecting the positive line of the supply to pin 3
as well as pin 1 of the EXT. POWER SUPPLY socket.
Supply Check
Before using an external power supply, it is advisable to check that it can deliver suffi-
cient power to operate the 6302 by setting the OUTPUT A selector to "Ch.A". The nee-
dle of the SUPPLY VOLTAGE meter should deflect over the blue area.
Remember to switch the 6302 off again when it is not in use.
3.1.3. Plug-in Power Supply Type 2808
12
To operate the 6302 from a 100 - 240 V AC (50 - 400 Hz) mains supply, the Power
Supply Type 2808 is available on separate order. This is shown in Fig . 3.2, and it may
be used externally to power the 6302 whilst at the same time recharging its plug-in
Power Pack, or it may be used internally (in place of the plug-in Power Pack) if only
mains operation is required .
Details of voltage and fuse selection for the 2808 are given in its Instruction Manual.
Fig . 3.2. Power Supply Type 2808
Internal Use
For this purpose the CHARGE switch on the front plate of the 2808 should be set to
"Off" and the 2808 plugged into the supply compartment of the 6302 in place of the
plug-in Power Pack. Installation of the 2808 and the supply check procedure is the
same as for the Power Pack.

External Use
For · external use, the OUTPUT socket of the 2808 should be connected to the EXT.
POWER SUPPLY socket of the 6302 using cable AO 0035. If the 2808 is to be used to
power the 6302 as well as to charge the Power Pack contained in the supply compart-
ment of the Waveform Retriever, the CHARGE switch of the 2808 should be set to
"Charge". If the Power Pack is already fully charged then the CHARGE switch should be
set to "Off".
External Charging of Separate Power Packs
If spare Power Packs are to be recharged outside the 6302, then it is necessary to use
also the Charging Adaptor AO 0157. Full details of the procedure are to be found in the
2808 Instruction Manual.
3.1 .4. Battery Charger ZG 0113
Fig. 3.3. Battery Charger ZG O 113
The Battery Charger ZG 0113 (fig .3.3) operates from mains supplies of 100 to 130 V or
200 to 240V AC (50 to 60 Hz). On delivery, the Charger is not fitted with a mains plug .
The mains cable is a four core cable, the coding for different voltages being :
Blue-Black: 100 to 1 30 V AC
Blue-Brown: 200 to 240 V AC
Yellow / Green: Ground
To recharge the internal Ni-Cd cells of the 6302, connect the DIN plug of the Battery
Charger to the EXT. POWER SUPPLY socket of the 6302. This, however , disconnects
the Power Pack from the supply circuitry and it is not possible to operate the 6302 while
the Charger is connected.
Although primarily intended for charging, ZG 0113 may also be use .d for mains opera-
tion of the 6302 . For this purpose, the metal sleeves of the Charger plug should be rem-
oved and pins 1 and 3 of the plug should be short-circuited . The Power Pack (loaded
with rechargeable cells) may remain in the battery compartment of the 6302 or may be
removed .
3.2. SELECTION OF RECORDING PARAMETERS
Although mainly intended for fixed-frequency measurements, the 6302 may be used
with slow frequency sweeps, as long as the LOCK ERROR indicator does not light.
13

3.2.1. Trigger Signal
The trigger signal may be either the signal fed to channel A of the 6302, or an external
trigger signal connected to the EXT. TRIGGER INPUT. The signal must be a clean, peri-
odic waveform with the same fundamental frequency as the signals to be processed.
When fed to the EXT. TRIGGER INPUT, the signal should be in the range 50 mV to 20 V
peak - to -peak.
On rotating machinery , the trigger signal may be delivered by the B & K Photoelectric
Transducer MM 001 2 or Magnetic Transducer MM 0002, which are both contact-free
transducers .
The Photoelectric Transducer MM 001 2 is a combined infra-red light source and pickup
device
built into a common housing . It is positioned up to 15 mm from a convenient ro-
tating machine part so that the light beam is reflected back from a contrasting band att-
ached to the part . The transducer should be connected to the EXT. TRIGGER INPUT on
the rear panel of the 6302, which provides the necessary DC supply voltage via its inner
shield .
The Magnetic Transducer MM 0002 is a velocity transducer which connects directly to
the EXT. TRIGGER INPUT on the front panel of the 6302 . It will normally be necessary
to attach on the machinery one of the high permeability discs delivered with the Trans -
ducer .
3.2.2. Sweep Period and Filter Bandwidth
14
A basic requirement is that the signal to be processed be available (3nd stationary) dur-
ing at least one sweep period.
The main considerations for selecting the sweep period, Ts. and filter bandwidth, B, are
the number, n, of harmonic components which are to be reproduced and the noise con-
tent of the input signal.
As the distance between the harmonic components of the output signal is Lit = 1/ Ts,
the number of components falling within the filter bandwidth is given by n = Ts B. Differ -
ent recordings of the same signal may therefore be made with different settings of the
SWEEP PERIOD and LOWPASS FILTER controls, depending on the information of inter -
est , such as unbalance, tooth meshing, etc .
In order to avoid aliasing the number of harmonic components within the filter band -
width is limited to 1 80, since one period of the fundamental is divided into 360 parts.
As described in the Introduction, all frequencies falling outside the equivalent filters
(bandwidth 2B) centered on the multiples of the sampling frequency are suppressed in
the output signal. For instance, if the harmonic waveform is mixed with wide - band
white noise , the RMS noise level of the output signal is reduced by a factor of v'f
5/
2B
(f s = sampling frequency).
Hence, the SWEEP PERIOD and LOWPASS FILTERS controls should be set so that the re-
quired number of harmonics are contained in the filter bandwidth . If the recording
shows too much noise on the output signal , the filter bandwidth should be decreased
and the sweep period should be increased correspondingly. Fig . 3.4 gives the number of
components within the filter bandwidth as a function of the sweep period for the differ -
ent filter bandwidths provided by the 6302 .