8.14 Diagnostic Tools
8.14.2 Easy FFT
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8.14.2
Easy FFT
The machine is made to vibrate and a resonance frequency is detected from the generated
vibration to set notch filters according to the detected resonance frequencies. This is used to
eliminate high-frequency vibration and noise.
During execution of Easy FFT, a frequency waveform reference is sent from the SERVOPACK to
the Servomotor to automatically cause the shaft to rotate multiple times within 1/4th of a rota-
tion, thus causing the machine to vibrate.
Execute Easy FFT after the servo is turned OFF if operation of the SERVOPACK results in high-
frequency noise and vibration.
Easy FFT is built into the SERVOPACK for compatibility with previous products. Normally use
autotuning without a host reference for tuning.
Preparations
Check the following settings before you execute Easy FFT.
•
The parameters must not be write prohibited.
•
The main circuit power supply must be ON.
•
The test without a motor function must be disabled (Pn00C = n.
0).
•
There must be no alarms.
•
There must be no hard wire base block (HWBB).
•
The servo must be OFF.
•
There must be no overtravel.
•
An external reference must not be input.
WARNING
Never touch the Servomotor or machine during execution of Easy FFT. Doing so may result
in injury.
CAUTION
Use Easy FFT when the servo gain is low, such as in the initial stage of servo tuning. If you
execute Easy FFT after you increase the gain, the machine may vibrate depending on the
machine characteristics or gain balance.
Frequency
waveform
reference
Response
SERVOPACK
Servomotor
Travel distance
Travel distance
