MMF VM30-H, Инструкция по эксплуатации, Страница: 29 / 58

9.3. Display Modes
In the signal setup menu, filter selection is followed by the display mode. The next sections
describe the available display modes.
9.3.1. Running RMS
Running RMS with the display abbreviation “RMS” is defined as:
∫
−
=
0
0
) (
1
) (
2
0
t
t
w W
dt t a t a
τ
τ
where
) ( t a
W
is the instantaneous value of the selected vibration quantity (human vibration,
acceleration, velocity or displacement) at the time
t
(integration variable)
τ
is the integration time (1 second for VM30-H)
0
t
is the time of observation
If an overload occurs during the measurement of running RMS, a message OVER LOAD is
displayed instead of the corresponding measuring value until normal magnitudes are measured
again.
9.3.2. Maximum Transient Vibration Value (MTVV)
The maximum transient vibration value is the highest magnitude of the running RMS from the
start of measurement. It has the display abbreviation “MTVV”.
A measurement is started by pressing the ESC key which resets the MTVV display to zero.
If an overload occurs during the measurement of MTVV, a message
OVER LOAD is displayed
instead of the corresponding measuring value. The overload indication remains on the display
even if the measured magnitudes return to normal values since the measured maximum value
was invalid. The overload indication can be reset by pressing the ESC key.
9.3.3. Interval RMS (A(T))
The interval RMS with the display abbreviation “A(T)” is defined as
∫
=
T
w W
dt t a
T
a
0
2
) (
1
where
) ( t a
W
is the instantaneous value of the selected vibration quantity (human vibration,
acceleration, velocity or displacement) at the time
t
(integration variable)
T
is the duration of measurement
24