Mitsubishi Electric MELSERVO-JN Series, Instruction Manual

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6. 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)
=
Speed loop gain setting
(1 load to motor inertia moment ratio) 2
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 to motor 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)
2000 to 3000
Speed loop gain setting/ (1 load to motor inertia moment ratio setting)
3) Model loop gain (PG1: parameter No. PB07)
This parameter determines the response level for the position command. Increasing the model loop
gain improves the trackability to a position command. If the gain is too high; however, overshooting
is likely to occur when settling.
Speed loop gain setting
(
(1+ load to motor inertia moment ratio )
1
8
1
4 to
)
Model loop gain guideline
(2) For position control
(a) Parameters
The following parameters are used for gain adjustment.
Parameter No. Abbreviation Name
PB06 GD2 Load to motor inertia moment ratio
PB07 PG1 Model loop gain
PB08 PG2 Position loop gain
PB09 VG2 Speed loop gain
PB10 VIC Speed integral compensation