MMF VM30-H, Инструкция по эксплуатации, Страница: 14 / 58

5.2.2. Settings on the VM30-H
For hand-arm vibrations it is recommended to report both the interval RMS for each axis and
vibration total value (Ahv). Therefore both measurements are described in this section.
Select first the measuring ranges for X, Y and Z. A good method is starting with the most
sensitive range. Press the MENU key and open the menu “1/8: Gain” with OK. Set the
measuring ranges for X, Y and Z to 12 m/s² by the ▲▼ keys and confirm each entry with OK
(see p. 28).
Presse the key ▲ (Range) and chose with the ▲▼ keys “human vibration”. Press OK and select
the weighting filter “H/A Wh”. Confirm with OK. Hand arm vibration is always measured with
the weighting filter W
h
(compare p. 21).
Select in the following menu the display mode “A(T)” for interval RMS (p.24).
Ignore the question “Save settings?” by pressing ESC.
Measurement is started by pressing the ESC key. This resets the averaged RMS values and the
timer to zero. The start of measurement must be after the start of vibration exposure. Otherwise
the result, averaged over the entire measuring time, would be wrong. The duration of
measurement shall represent a typical work process. Usually 10 seconds are sufficient for hand-
arm vibrations. The elapsed measuring time can be seen in the upper left display corner. A
sufficiently long duration of measuerement is reached if the measuring values do not change
anymore.
If an overload should occur during measuerement, the message “OVERLOAD” will appear
instead of the measuring value (compare p. 29). The measuring result is invalid even if there
was only a short overload. For this reason the display will show “Overload” as soon as an
overload occurs on any channel. This message can be erased only after pressing ESC.
If an overload is indicated, increase the measuring range for the respective channel, wait a few
seconds until the instrument has settled and start a new measurement by pressing ESC. The
measuring range shall not be higher than necessary in order to provide maximum display
resolution.
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Figure 6: Coordinate system of the hand (from ISO 5349-1)