Threshold value consideration for averaged magnitude spectra

This sample illustrates an analysis chain for threshold value consideration, as explained in the Frequency analysis application concept. The analysis chain implements the calculation of a magnitude spectrum, averaging of several magnitude spectra and subsequent threshold value consideration for exemplary frequency bands. For a better illustration of the threshold value consideration around 50 Hz, the scope is limited to the frequency range from 0 Hz to 100 Hz.

The sample is available for download from here:
FrequencyAnalysis_Sample.zip

Block diagram for the analysis chain:

Threshold value consideration for averaged magnitude spectra 1:

Program parameters

The table below shows a list of important parameters for the configuration of the function blocks that are used.

FFT length

8192

Window size

6400

Buffer size

3200

Window type

eCM_HannWindow

Scaling type

eCM_RMS

Coefficient order

eCM_Mean

Maximum number of classes

1

Requirements

Development environment

Target system type

PLC libraries to include

TwinCAT v3.1.4013

PC or CX (x86, x64)

Tc3_CM, Tc3_CM_Base, Tc3_MultiArray