Yaskawa F7 Drive User Manual - Manual (Page 151)

Diagnostics & Troubleshooting 6 - 26
Oscillation and hunting occur with Flux Vector control.
The gain adjustment may be insufficient. Adjust the speed control loop (ASR) gain (C5-01). If the oscillation points overlap
with those of the machine and cannot be eliminated, increase the ASR primary time delay constant (C5-06), and then readjust
the ASR gain (C5-01).
Vector Control may not perform optimally if Auto-Tuning has not been performed. Therefore, perform Auto-Tuning.
Alternatively, change the Control Method Selection (A1-02) to V/F Control (0 or 1).
Oscillation and hunting occur with PID control.
If there is oscillation or hunting during PID control, check the oscillation cycle and individually adjust the P, I, and D
parameters.
• Disable Integral (I) and Derivative time (D) control.
• Reduce the proportional gain (P) until hunting stops.
• Reintroduce the integral function, starting with long integral time values, to eliminate the P offset.
• Reintroduce the derivative time and adjust with small increments to eliminate oscillation.