KutupASP DijitalData from a vibration sensor cannot be interpreted without knowing which quantity it measures, which frequency range it sees and how it was mounted.
Vibration is expressed as displacement, velocity or acceleration. Displacement is more informative at low frequencies, velocity at mid frequencies and acceleration at high frequencies. For overall machine condition the RMS of velocity is commonly tracked; for high-frequency events such as bearing defects, acceleration and envelope analysis are used.
The fast Fourier transform (FFT) splits a time series into frequency components. An unbalance usually shows at the running frequency, a misalignment at multiples of it. That is a general rule; the interpretation on a particular machine depends on its geometry and speed. If speed varies, normalize the spectrum to the running frequency.
Mounting position and method change the measurement; a loose mount suppresses high frequencies. The sampling rate must be at least twice the highest frequency of interest, with an anti-alias filter before it. When these conditions are not met, components visible in the spectrum may not be real.
Overall level, RMS, peak, crest factor and energy in selected frequency bands can be model inputs. Store every feature with its load and speed context. Take acceptance limits from the relevant standards and the machine manufacturer; this guide gives no limit value for a specific machine.
Displacement is more informative at low frequencies, velocity at mid frequencies and acceleration at high frequencies. For overall machine condition, the RMS of velocity is commonly tracked, while bearing defects call for acceleration and envelope analysis. Take acceptance limits from the relevant standards and the machine manufacturer.
A loose mount suppresses high frequencies, so mounting matters. The sampling rate must be at least twice the highest frequency of interest, with an anti-alias filter before it. When these conditions are not met, components visible in the spectrum may not be real.
Pilot steps in this guide are proposed engineering workflows. Examples do not constitute measured field performance.
After reading, you can compute frequency resolution for a vibration record, justify your window choice, and read spectral peaks as clues rather than diagnoses, using a worked example.
This article shows how envelope analysis pulls repeating impacts out of a high-frequency vibration band, how to calculate the four defect frequencies, and how to read the result step by step.
After reading, you can set a sampling rate from your analysis band, recognise a false low-frequency peak caused by aliasing, and see why slow PLC or SCADA logs fall short for spectra.
