Mitsubishi Electric MELSERVO-J2S Series Transition Handbook page 489

[Appendix 1] Summary of MR-J4_B_-RJ020 + MR-J4-T20
(c) Vibration tough drive function
This function prevents vibration by resetting a filter instantaneously when machine resonance occurs
due to varied vibration frequency caused by equipment aging.
The vibration tough drive function operates when a detected machine resonance frequency is within
±30% for the machine resonance frequency estimated by the adaptive filter II function.
POINT
Resetting the machine resonance frequency by the vibration tough drive function is
performed constantly. However, the number of write times to the EEP-ROM is
limited to once per hour.
The vibration tough drive function does not detect a vibration of 100 Hz or less.
When the machine resonance does not stop after the vibration tough drive function
resets the machine resonance frequency, perform the adaptive tuning again.
Appendix 1-26