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Sens.
l e v e l - - - A. V & F
~
: -D
!'\._,:--,
r-Unit~
The charge sensitivity can be finely
adjusted from the front panel or via
the interface bus.
No.
m
i s'
9
mV
/
Unn
I
,-,
n
m
/
s
in
/
s
I. Ll
u
mm
m
•
pC
/
Unit
N
lbf
'--Exp.----J
Vibration meter section
Fig.
1. Vibration-meter LED display showing the selected accelerometer charge-sensitivity
The vibration meter can control
nine different vibration-levels across
the test frequency range. Consequent-
ly, complex test programmes, con-
forming to IEC 68-2-6 and MIL-STD-
810C, can be performed. For instance,
the IEC standard requires only dual-
parameter control, but the MIL stan-
dard requires a more stringent proce-
dure involving a larger number of
cross-overs and multi-parameter con-
trol.
Easy-to-use front panel
The field -entry system incorporates
a keyboard, for direct entry of vibra-
tion test parameters, and a thumb-
wheel for coarse and fine adjustment
of these settings. Each parameter val-
ue is shown on the LED display when-
ever the associated key is
pressed.
A
front panel set-up sequence leads
t
he
user through the selectable parame-
ters,
one at a time, in a logical order.
Set-up selection can be simplified by
storing the parameters in one of
t
he
four front- panel memories, allowing
instant recall of the required test set-
up. Further test set-ups can be stored
externally, for example by a digital
tape recorder or desk-top calculator,
and used to set the front-panel test
parameters via the IEEE interface
bus.
Signal generation
The generator provides a digitally-
controlled sinusoidal output which
sweeps in frequency between selec-
table limits. These limits may be cho-
sen within the frequency range from
1Hz to 10kHz. The minimum selec-
table frequency band is 0,3 Hz. Both
linear
and
logarithmic
frequency
sweeps are available with selectable
sweep-rates from 0,001 to 100 Hz/s,
and 0,001 to 100 oct/min respectively.
Frequency control may be either auto-
matic or manual.
....------Vibration M e t e r - - - - - ,
Ext.
Filter
In/
Out
Fig.
2.
Preamplifier input-connectors and
sensitivity
selection
2
Built-in preamplifier
The built-in charge preamplifier en-
ables direct connection of accelerome-
ters and force transducers. The vibra-
tion-meter LED display showing the
selected charge sensitivity can be seen
in Fig.
1.
The charge sensitivity is se-
lectable at discrete values in the range
1 to 31,6
pC/ms-
2
for accelerometers,
and is 4 pC/N for force transducers.
The charge input is particularly suit-
able for use with Brtiel & Kjrer force
transducers and
uni-gain®
accelerom-
eters.
Any vibration transducer and pre-
amplifier combination can be used
with the controller, by connection
with the voltage input. The user can
select either a force or an acceleration
input sensitivity.
The instrument is provided with se-
lection of either floating- or grounded-
input for elimination of ground loops.
Connection of transducers is made via
a TNC connector for charge input and
a BNC connector for voltage input.
The corresponding sockets and the
sensitivity values are shown in Fig. 2.
c:
.Q
tU
Qj
Qi
(J
(J
c(
Constant
Velocity
(6 dB/Oct)
The measured vibration level can be
continuously monitored on the LED
display, at the touch of a key. It can
also be displayed on an oscilloscope,
measuring amplifier or voltmeter by
using the preamp. output on the front
panel.
The Vibration Exciter Control Type
1053 can automatically calculate the
smooth cross-over frequencies when
more than one vibration level is set.
Alternatively, or in
addition,
the
cross-overs may be set directly, which
is useful when the required test pro-
gramme includes steps in the vibra-
tion level. Examples of typical tests
are shown in Figs. 3 and 4.
Constant acceleration, velocity,
displacement and force
A constant level of vibration excita-
tion can be attained by using a feed-
back signal to the compressor section.
Constant
Acceleration
Cross-overs.
Frequency
851819
Fig. 3. Multi-parameter test-programme control. This test uses four pre-set vibration levels
requiring three cross-overs which are calculated by the controller
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