MN100003 REV A (12/07/10)
Page 19
Caution: The VibraCheck Limited and VibraCheck II accepts ICP* type accelerometers only. The
accelerometer must be 100mV/G +- 30% for proper functionality.
*ICP is a trademark of PCB piezoelectric Inc.
Calibration and factors:
Calibration should be completed by Metrix Instruments or by authorized dealers only.
Calibration of the VibraCheck Limited and VibraCheck II is performed via a set of gain factors. Each gain factor
is set at the factory prior to shipment.
Factor 1: acceleration = gain x 1
Factor 5: Displacement = gain x 1
Factor 2: acceleration = gain x 10
Factor 6: Displacement = gain x 10
Factor 3: Velocity = gain x 1
Factor 7: Bearing = gain x 1
Factor 4: Velocity = gain x 10
Factor 8: Bearing = gain x 10
Adjusting the Factors:
Turn the data collector on while pressing the acceleration key. Continue to press the key until the data collector
beep 3 times. At this time the calibration mode of accelerometer sensitivity is selected. Continue to press (and
hold) the acceleration key again and wait for 10 seconds. The data collector will beep 3 times again. At this time
the calibration mode of the correcting factors is selected. Release the acceleration key.
Press the “backlit” (on/ off) key to select the correcting factors. The number of correcting factors will appear at
the right hand bottom corner when pressing the backlit key.
Press displacement key to increase the selected correcting factor (%). Press velocity key to decrease the selected
correcting factor (%). Press the acceleration to save the setting.
Turn the data collector off to complete the calibration process.
Calibration procedure
Set all the correcting factors to be 100.0 (%)
Install the accelerometer on a shaker, on which a standard accelerometer is installed. The standard accelerometer
is connected to a standard rms data collector.
Drive the shaker with appropriate sine signal and record the readings of acceleration (x1, x10), velocity (x1, x10)
and displacement (x1, x10) respectively.
Compare the reading with the standard values that derived from the standard accelerometer and data collectors.
Adjust the correcting factors, such that the readings multiplied by the correcting factors will be equal to the
standard values.
DC offset
The calibration for DC offset is not needed because the VibraCheck Limited and VibraCheck II vibration meter
always calibrates the DC offset error automatically when power on.
