Mitsubishi Electric FR-F820-00077 Instruction Manual page 228

Speed control under PM motor control
Adjusting the speed control gain manually
● The speed control gain can be adjusted for the conditions such as abnormal machine vibration,
acoustic noise, slow response, and overshoot.
● Pr. 820 "Speed control P gain 1" = "25 % (initial value)" is equivalent to 50 rad/s (speed response
of a single motor). (Equivalent to the half the rad/s value with the FR-F820-03160(75K) or higher
and FR-F840-01800(75K) or higher.) Setting this parameter higher speeds up the response, but
setting this too high causes vibration and acoustic noise.
● Setting Pr. 821 "Speed control integral time 1" lower shortens the return time to the original speed
during speed fluctuation, but setting it too low causes overshoot.
200 (100) rad/s
50 (25) rad/s
The value in parentheses is applicable with the FR-F820-03160(75K) or higher and FR-F840-
01800(75K) or higher.
● Actual speed gain is calculated as below when load inertia is applied.
Fig. 5-6:
Actual speed gain = Speed gain of a single motor ×
JM: Motor inertia
JL: Load inertia converted as the motor axis inertia
5 - 56
Proportional gain
25 % 100 %
(Initial value)
Load
fluctuation
Speed
Speed characteristic at load fluctuation
Fig. 5-5:
Setting of the proportional gain
Pr. 820
Setting
Since increasing the proportional gain enhances the
response level and decreases the speed fluctuation.
Decreasing the integral time shortens the return time taken.
JM
JM + JL
Parameters
I001483E
I001484E