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VM-4424S/H Instruction Manual
(Compatible with Version 2.16 or later)
Envelope Waveform: Envelope waveform means the peak trajectory of the vibration waveform.
For example, vibration due to rolling bearing deterioration occurs in
DC to 1kHz band due to rotation, and is modulated by the natural
frequency (2k to 15kHz) of the bearing and transmitted to the bearing
housing.
This vibration is detected, the absolute value is taken, and
the peak locus of the high-frequency vibration waveform of 2k to
15kHz can be obtained by 1kHz low-pass filter processing.
H-function: When a 2k to 15kHz signal passes through a 1kHz filter in envelope processing, it
is rectified to become a direct current component, and a waveform in which an
envelope waveform of DC to 1kHz is superimposed on it. This waveform is called
H-function, and indicates the magnitude and amount of fluctuation in the high
frequency range.
A waveform obtained by removing DC component from H-function and
extracting only the fluctuation component from DC to 1kHz is output from
ACOUT in VM-4424 in the same way VM-4416.
For the indicator and
DCOUT, you can switch between H-function and the fluctuation component
(below fig.10-1 and refer to section 4-4-2).
Fig.10-1 Waveform Process of H-function
Bearing Vibration due to Scratches
ACOUT Waveform
H-function Waveform
Envelope
+ DC Cut
Envelope
DCOUT
(H-function Coupling: DC)
Envelope Waveform
DC Cut
DCOUT
(H-function Coupling: AC)
Rectification
Rectification
