Svantek SV 977D - Page 355

355
SV 977D User Manual - Appendixes
D.2. VIBRATION LEVEL METER
D.2.1 Basic terms and definitions (VLM mode)
T
current time period of the measurement in seconds.

exponential time constant in seconds for the given time-weighting. The following time
constants are available: 100 ms, 125 ms, 200 ms, 500 ms, 1.0 s, 2.0 s, 5.0 s, 10.0 s.
W
frequency-weighting filter (HP, HP1, HP3, HP10, Vel1, Vel3, Vel10, VelMF, Dil1, Dil3, Dil10,
or Wh).
( )
ta
W
instantaneous frequency-weighted signal with the weighting filter W.
( )
ta
W 
instantaneous frequency and time-
weighted signal with the weighting filter W
and time constant

calculated from the
equation:
( ) ( )
( )

 −
  =
  − −


t
/t
dea
1
ta
2
WW
,
where:

– variable of integration.
( )
tv
instantaneous vibration signal depends
on the <RMS Integration> parameter:
( )
( )
( )



=
=

=
Exp nIntegratioRMS
Lin nIntegratioRMS
ta
ta
tv
W
W
D.2.2 Definitions and formulas of the VLM result
The instrument calculates the vibration measurement results for three profiles. The calculation flow diagram
for one profile is presented below:
a
2
wτ
(t)
τ = 10s
τ = 100ms
a
w
(t)
a(t)
a
2
w
(t)
Peak, P-P
Max, MTVV
RMS
τ = …