Please note that the autoranging function is deactivated when measuring interval RMS. Select a
fixed measuring range before starting the measurement (see section 10). If autoranging has been
activated, a message is displayed after the selection of interval RMS, showing that autoranging
is not available in this mode and the respective channel is set to gain = 0.1, corresponding to the
highest range. Another measuring range can be selected manually, if desired (see section 10).
Measurement is started with the ESC key. The displayed A(T) value is then reset and the
integration timer restarted. The elapsed integration time is displayed in hours, minutes and
seconds in the upper left corner of the display, alternating with the record number.
Maximum integration time is 10 hours.
If an overload occurs during the measurement of interval RMS, a message
OVER LOAD
is
displayed instead of the corresponding measuring value until normal magnitudes are measured
again. Additionally, a message
Overload
is displayed in the center above the measuring values,
alternating with the filter type (Figure 10). This indicates that an overload has occurred in at
least one channel during the entire integration time. It can be reset by starting a new
measurement using the ESC key.
In contrast to the running RMS, the interval RMS does almost not react to short vibration
events. Interval RMS is of particular interest for the measurement of human vibration.
9.3.4. Estimated Vibration Dose Value (eVDV)
The Vibration Dose Value is the integrated fourth power vibration value with the unit m/s
1,75
. It
is used for whole-body vibration measurement. Its particular advantage is the higher sensitivity
to vibration peaks.
The VM30-H uses instead of VDV the so-called Estimated Vibration Dose Value with the
display abbreviation “eVDV”. It is described in annex B.3.1 of ISO 2631-1 as:
4
4
,
1
T
a
eVDV
W
⋅
⋅
=
where
W
a
the running RMS of vibration acceleration
T
the duration of measurement in seconds
Measurement is started by the ESC key. The displayed eVDV value is then reset and the
measurement timer started. The elapsed measuring time is displayed in hours, minutes and
seconds in the upper left corner of the display, alternating with the record number.
If autoranging has been activated, a message is displayed after the selection of eVDV, showing
that autoranging is not available in this mode and the respective channel is set to gain = 0.1,
corresponding to the highest measuring range. Another range can be selected manually, if
desired (see section 10).
If an overload occurs during the measurement of eVDV, a message
OVER LOAD
is displayed
instead of the corresponding measuring value until normal magnitudes are measured again. In
addition a message
Overload
is displayed in the center above the measuring values, alternating
with the filter type (Figure 10). It indicates that an overload occurred in at least one channel
during the entire integration time. It can be reset by starting a new measurement using the ESC
key.
The measurement of eVDV is only possible if acceleration or human vibration were selected.
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