Aerotech UNIDEX 600 Series, User Manual

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AerTune U600 User’s Guide
5-6
Aerotech, Inc.
Version 1.4
5.3.2. FFT Analysis
Clicking the Analysis menu selection will graphically display the spectral frequency
distribution of the item selected from the “Data to Analyze” menu. This will allow you to
determine if there is a resonant frequency present in the servo loop and /or mechanics of
the system. A peak, such as that shown in Figure 5-4, at approximately 400 Hz, is
indicative of a resonance. In this case, a 375 Hz low-pass filter might be used. If there is a
resonant frequency, see Identifying an Instability within the Servo Loop (Section 5.3.4.).
Figure 5-4. FFT Analysis
5.3.2.1. The FFT Analysis Window Menu Description
Print Menu You may Export or Print the plot.
Data to Analyze You may select the item to analyze:
Velocity Feedback, Velocity Command, Velocity Error, Position
Feedback, Position Command, Position Error, or Torque
Display Menu You may select the number of points to display on the plot:
64, 128, 256, 512, 1024, 2048, 4096, 8192
Tools Menu Disable Bias Correction
Low Pass Filter Data
Remove DC Bias from Position Data
Remove DC Bias from Torque Data