BRUEL & KJAER 2203 - Vibration Measurement Procedure

3.5.3. Calibration using the Internal Reference Voltage
The stable internal voltage (± 0,2 dB at about 1000Hz) in the 2203 may also be used for
calibration, as follows:
1. Connect the accelerometer to the 2203 using one of the methods shown in Fig.3.3.
If an integrator is used, set it to the required position ("Ace.", "Vel.", or "Disp.").
2. Pull the METER SWITCH out, and set it to "Batt." to check the batteries; then set it
to "Fast" and "Lin . ". (The instrument warm-up time is 20 s.)
3. Set the ATIENUATORS of the 2203 so that "Ref ." is inside the red lines (adjacent
to the black dot) and turn the ADJ. potentiometer with a small screwdriver to give
one of the following readings, depending on the method of connection:
K-factor of "0" dB
K-factor of "+ 0,8" dB
K-factor of"+ 1 ,2" dB
for Integrator ZR 0020
for JJ 2614
for JJ 2615
4. The 2203 is now calibrated so that a reading of "94" dB corresponds to 1 g RMS us-
ing an accelerometer with a sensitivity of 50 mV /g. For accelerometers of different
sensitivities, the results should be corrected afterwards, as explained in section
3.7.3.
3.6. VIBRATION MEASUREMENTS
3.6.1. General
When using the 2203 as a preamplifier and measuring amplifier for an accelerometer, it
should be remembered that the accelerometer has a high-frequency resonance (given on
its calibration chart) which probably lies within the frequency range of the meter. Mea-
surements should therefore be made with the use of an appropriate supplementary low-
pass filter, or with a band-pass filter set (see Chapter 1 ), to prevent measuring the re-
sults of the resonance, where it is thought possible that the signal may contain such
high frequencies. The lower limiting frequency of the measuring system is set at 10Hz
by the 2203.
For detailed instructions on the use of the accelerometer, see its Instruction Manual.
The 2203 itself should be kept out of the vibration environment.
3.6.2. Procedure for Vibration Measurements
20
1. Calibrate the 2203 (including checking the batteries) as described in section 3.5,
and mount the accelerometer by one of the methods described in its Instruction Man-
ual.
2. Set the METER SWITCH to "Lin." "Fast".
3. Set the OUTPUT ATIENUATOR (transparent) fully clockwise so that the red lines are
adjacent to the black spot.
4. Adjust the INPUT ATIENUATOR (black) to give the highest possible meter reading
without over-deflecting .