BISOPE series 66- How to set the
appropriate frequency for measurement (Setting the maximum frequency for
vibration measurement)
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If
you measure vibration using an FFT vibration meter, there are many things to consider
in advance compared to measuring other physical quantities (temperature,
displacement, pressure, etc.). Above all, the most difficult question at first
is “How many Hz should I set?”
However, if you have a simple vibration meter, you don’t have to worry much.
This is because general vibration meters cannot perform FFT processing (they
only use the time waveform without frequency setting itself and use the
appropriate filtering to cut out the area that can be measured). However, FFT
meters are different. If you set the frequency incorrectly, you may not be able
to see the desired signal at all, and since it is a fundamental problem, it can
be difficult.
Frequency setting (maximum frequency Fmax and
sampling frequency)
When
setting the frequency for vibration measurement, you basically set the maximum frequency (Fmax). This means the highest frequency on the horizontal axis of the spectrum graph. In the past, advanced FFT types expressed this as sampling frequency
(sampling rate), which is usually twice the Fmax in vibration measuring
instruments. To be exact, it is 2.56 times, but it is set to 2 times.
Therefore, if you ask about the sampling frequency, you can divide the maximum
frequency by 2. However, it is not important to enter the setting value, but to
think in advance about, for example, 'What can I see if I set
Fmax to 1000 Hz?'. See below.
#vibration measuring
instrument, #frequency setting, #Fmax, #maximum frequency, #sampling frequency,
#sampling rate, #FFT, #3-axis vibration sensor, #acceleration sensor,
#vibration education, #building vibration, #vibration measurement, #resonance
analysis, #resonance measurement, #vibration monitoring, #vibration noise
consulting www.kCBM.kr, https://blog.naver.com/vs72 , https://contents.premium.naver.com/bisope/visope
