Mitsubishi Electric MELSERVO-J3 Series Instruction Manual page 339

9. GENERAL GAIN ADJUSTMENT
(c) Adjustment description
1) Speed loop gain (VG2: parameter No.PB09)
This parameter determines the response level of the speed control loop. Increasing this value
enhances response but a too high value will make the mechanical system liable to vibrate. The actual
response frequency of the speed loop is as indicated in the following expression.
Speed loop response
frequency(Hz)
2) Speed integral compensation (VIC: parameter No.PB10)
To eliminate stationary deviation against a command, the speed control loop is under proportional
integral control. For the speed integral compensation, set the time constant of this integral control.
Increasing the setting lowers the response level. However, if the load inertia moment ratio is large or
the mechanical system has any vibratory element, the mechanical system is liable to vibrate unless
the setting is increased to some degree. The guideline is as indicated in the following expression.
Speed integral
compensation setting(ms)
3) Position loop gain (PG2: Parameter No.PB08)
This parameter determines the response level to the disturbance of position control loop. Increasing
the position loop gain enhances response level to a disturbance, but a too high value will make the
mechanical system liable to vibrate.
Model control gain
guideline
4) Model loop gain (PG1: parameter No.PB07)
This parameter determines the response level to a position command. Increasing model loop gain
improves track ability to a position command but a too high value will make overshooting liable to
occur at the time of settling.
Model loop gain
guideline
=
(1 + ratio of load inertia moment to servo motor inertia moment) × 2
Speed loop gain setting/
Speed loop gain setting
(1 + ratio of load inertia moment to servo motor inertia moment)
Speed loop gain setting
(1 + ratio of load inertia moment to servo motor inertia moment)
Speed loop gain setting
2000 to 3000
(1 + setting ratio of load inertia moment to
servo motor inertia moment)
9 - 10
1 1
× to
4
8
( )
1 1
to
×
4 8