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The weightings specifically used for human vibration allow for the directional
effects of vibration on people and compensate the vibration level to match the
human discomfort throughout the frequency range of the weighting applied. As
an example, study the gain response of the Wh filter and notice that it has a gain
of -0.43dB at 10Hz whereas at 100Hz the gain is -15.91dB. This is because for
HARM a human body is more susceptible to vibration levels at 10Hz than
100Hz and hence this is compensated for in the applied frequency weighting.
For ease of use, HARM and WBV display modes have set frequency weighting
filters automatically applied to the measured vibration signal. CUSTOM mode
allows any combination of frequency weighting filters within the axes whilst
SINGLE Axis allows the selection of any filter suitable for vibration monitoring.
These frequency weighting filters allowable for each axis and each display mode
is shown below: -
HARM
WBV
Axis Filter
Axis Filter
X Wh
X Wd
Y Wh
Y Wd
Z Wh
Z Wk
SINGLE
Filter
Fa, Fb, Fc, Fl, Fk, Ws
CUSTOM
Axis Filter
X
Fa, Fb, Fc, Fl, Fk, Wb, Wc, Wd, We, Wh, Wj, Wk, Wm, Ws
Y
Fa, Fb, Fc, Fl, Fk, Wb, Wc, Wd, We, Wh, Wj, Wk, Wm, Ws
Z
Fa, Fb, Fc, Fl, Fk, Wb, Wc, Wd, We, Wh, Wj, Wk, Wm, Ws
Filter responses can be viewed under
Technical
Specification
in
Chapter 10
.