Table of Contents
Advertisement
Cepstrum analysis
A cepstrum is the 'spectrum of a spectrum' and is particularly
suitable for detecting regular structures in a frequency spectrum.
Above all, in the case of complex patterns with many harmonics and
sidebands - that frequently occur if roller bearings or gearings are
damaged- a cepstrum simplifies the evaluation of the measurement
data.
User-defined measurement quantities
As well as measurement tasks with fixed specified measurement
quantities, VIB XPERT provides measurement tasks where the
measurement quantities can be freely defined. The voltage (±30V,
AC/DC) or current (±30mA, AC/DC) can be connected as an input
signal and recorded as an overall value, as a time waveform* or as a
spectrum*. The assignment of the input signal to the measurement
quantity is specified by the 'Measurement quantity' and 'Unit'
parameters in the transducer setup (see P. 2-20).
Examples of user-defined measurement quantities:
- Measurement of the pressure as a current level (4-20mA, DC).
Connection to pressure transmitter.
- Measurement of the flow rate as a current or voltage signal (4-
20mA / 0-10V, DC). Connection to flow rate measuring device.
- Measurement of the sound pressure as a time signal or spectrum.
Connection to a microphone.
- Displacement measurement (inductive sensor VIB 6.640).
Only the following cables can be used as sensor cables:
VIB 5.433 - Connection cable for low voltage signals
VIB 5.434 - Connection cable for low current signals
VIB 5.433 /
VIB 5.434
Pressure
Flow rate
Measurement tasks
Cepstrum
AC overall
DC overall
AC time
AC Spectrum
waveform
* DC measurement for time waveform,
spectrum, see page 5-30.
Attention!
Sensor parameters for
sound pressure measurement
5-19
Advertisement
Table of Contents
