PRÜFTECHNIK VIB 5.300 EX Series, Руководство по эксплуатации

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VIBXPERT 11.2010
The measurement tasks described on this page are only available in
the 'Route / Machine template' mode. The measurement parame-
ters are set in the OMNITREND PC software.
TrendingSpectrum
A TrendingSpectrum is a measurement template for the route mode.
It can be used to make data collection significantly faster and more
efficient. A TrendingSpectrum is based on a time signal measure-
ment. Based on the TrendingSpectrum, VIBXPERT first generates a
spectrum, which in turn is used to calculate up to 30 characteristic
overall values. The characteristic values result from the frequency
bands defined in OMNITREND and are used for condition monitoring
when recorded in the form of a trend.
Based on the spectrum, VIBXPERT also calculates a time signal
according to the settings in the OMNITREND software. The measure-
ment quantity of the recorded time signal may differ from the
measurement quantity of the measured time signal.
Order spectrum
In an order spectrum, the frequencies are recorded and displayed as a
multiple of the shaft rotational frequency (= order). In these
measurements, the RPM is recorded at the same time as the vibration
signal and is taken into account when the spectrum is calculated. If
short-term, system-related fluctuations in the RPM occur, the sample
rate of the time signal is adjusted accordingly ('resampling') to avoid
a 'smearing' of the frequencies.
An order spectrum cannot be converted into a frequency spectrum,
since the time and thus the frequency information are lost through
the resampling procedure.
Order-based spectrum
With this type of spectrum, the frequencies are converted into
orders*. The RPM is measured, manually entered or passed as a
parameter by the OMNITREND software. The maximum order to be
displayed is also required. Order-based spectra are advantageous
when machines run at different RPMs for process-related reasons
because the spectra are only comparable in relation to the RPM.
* Shaft rotational frequency = 1. Order
TrendingSpectrum
(Amplitude)
TrendingSpectrum
(Envelope)
Order
spectrum

Note
Measurement tasks