CESVA VC431, User Manual, Page: 22 / 72

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If you wish to modify one of the values press buttons “f-“ and “f+”, to select the 7 available
frequencies, or buttons “a-“ and “a+” if you wish to modify vibration magnitude. The latter
parameter will depend on the frequency chosen, since the 5 vibration magnitudes (RMS
value) on the calibrator are not available for each one of the frequencies. See the following
chart:
Frequency
[Hz]
15.915 40 80 159.15 320 640 1280
Acceleration (RMS)
[m/s
2
]
1-2 1-2-5 1-2-5-
10
1-2-5-
10-20
1-2-5-
10-20
1-2-5-
10-20
1-2-5-
10-20
Preferential values in the verification process according to ISO 8041:
Hand-arm: 10 m/s
2
at 80 Hz and at 159.15 Hz.
Buildings, Structure and Whole Body: 1 m/s
2
at 15.915 Hz.
4. Place the accelerometer in the head of the CV211 . It will suffice to press the
accelerometer against the calibrator head with the hand. Although it is advisable to connect
the accelerometer with a screw or by using a mounting magnet (see 4.21).
5. Take the VC431 to the main menu, and use the arrow buttons to select the sensitivity
adjustment icon and access it with the button.
The vibrometer display will show the level of RMS acceleration measured in each one of the
applications and on each one of its axes. You must know which application and which axis is
being measured at all times.
The tolerance for the reading of nominal acceleration is 5%. This means that for example if
you select an acceleration of 10 m/s
2
on the calibrator this acceleration value may be
between 9.5 and 10.5 m/s
2
for correct verification in the direction and application evaluated. If
the reading value is not in this range, the sensitivity of the vibrometer needs to be adjusted.
Otherwise the vibrometer is measuring properly and sensitivity need not be readjusted.
NOTE: The vibrometer's sensitivity can only be adjusted by authorised and technically qualified
personnel. The readjustment of sensitivity leads to loss of traceability in the calibration of the unit.