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6. GENERAL GAIN ADJUSTMENT
6.4 Interpolation mode
The interpolation mode is used to match the position control gains of the axes when performing the
interpolation operation of servo motors of two or more axes for an X-Y table or the like. In this mode, the
position control gain 1 and speed control gain 1 which determine command trackability are set manually
and the other gain adjusting parameters are set automatically.
(1) Parameter
(a) Automatically adjusted parameters
The following parameters are automatically adjusted by auto tuning.
DRU parameter No. Abbreviation Name
12 GD2 Ratio of load inertia moment to servo motor inertia moment
15 PG2 Position control gain 2
16 VG2 Speed control gain 2
17 VIC Speed integral compensation
(b) Manually adjusted parameters
The following parameters are adjustable manually.
DRU parameter No. Abbreviation Name
13 PG1 Position control gain 1
14 VG1 Speed control gain 1
(2) Adjustment procedure
Step Operation Description
1
Choose the auto tuning mode 1 (DRU parameter No. 8: 0001) and set the
machine resonance frequency of the response level to 15Hz 1 (DRU parameter
No. 9: 0001).
Select the auto tuning mode 1.
2
During operation, increase the response level setting (DRU parameter No. 9),
and return the setting if vibration occurs.
Adjustment in auto tuning mode
1.
3
Check the values of position control gain 1 (DRU parameter No. 13) and speed
control gain 1 (DRU parameter No. 14).
Check the upper setting limits.
4 Choose the interpolation mode (DRU parameter No. 8: 0000). Select the interpolation mode.
5
Using the position control gain 1 value checked in step 3 as the guideline of the
upper limit, set in position control gain 1 the value identical to the position loop
gain of the axis to be interpolated.
Set position control gain 1.
6
Using the speed control gain 1 value checked in step 3 as the guideline of the
upper limit, look at the rotation status and set in speed control gain 1 the value
three or more times greater than the position control gain 1 setting.
Set speed control gain 1.
7
Looking at the interpolation characteristic and rotation status, fine-adjust the
gains and response level setting.
Fine adjustment.
(3) Adjustment description
(a) Position control gain 1 (DRU parameter No.13)
This parameter determines the response level of the position control loop. Increasing PG1 improves
trackability to a position command but a too high value will make overshooting liable to occur at
the time of settling. The droop pulse value is determined by the following expression.
Droop pulse value (pulse)
Position control gain set value
60
Rotation speed (r/min)
131,072(pulse)
(b) Speed control gain 1 (DRU parameter No. 14)
Set the response level of the speed loop of the model. Make setting using the following expression
as a guideline.
Speed control gain 1 setting
Position control gain 1 setting 3