Easyfft - YASKAWA E-V-MD Series User Manual

9 Utility Functions

9.13 EasyFFT

EasyFFT sends a frequency waveform reference from the SERVOPACK to the servomotor and slightly rotates
the servomotor several times over a certain period, thus causing machine vibration. The SERVOPACK detects
the resonance frequency from the generated vibration and makes notch filter settings according to the reso-
nance frequency detection. The notch filter is effective for the elimination of high-frequency vibration and
noise.
Execute this function after the servomotor power is turned OFF if operation of the SERVOPACK results in
high-frequency noise and vibration.
• The servomotor automatically will move less than a quarter of a turn several times in the specified direc-
tion when EasyFFT is executed. Do not touch the servomotor or machine during execution of EasyFFT,
otherwise injury may result.
• Use the EasyFFT when the servo gain is low, such as in the initial stage of servo adjustment. If EasyFFT
is executed after increasing the gain, the servo system may vibrate depending on the machine character-
istics or gain balance.
In addition to this function, online vibration monitor can be used to detect machine vibration and automati-
cally make notch filter settings.
If a SERVOPACK is used to make adjustments, it is recommended to use advanced autotuning. This built-in
EasyFFT function is used to maintain interchangeability with previous models. There is normally no need to
use it.
(1) Preparation
The following conditions must be met to perform EasyFFT.
• The write prohibited setting parameter must be set to Write permitted.
• The main circuit power supply must be ON.
• All alarms must be cleared.
• The servomotor power must be OFF.
• There must be no overtravel.
• An external reference must not be input.
9-30
Periodic
waveform
reference
Response
SERVOPACK
WARNING
CAUTION
Rotates the
shaft slightly
Slight
movement