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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 g ain 1 w hich de termin e command trac kabili ty are set m anually
and the other gain adjusting parameter s are set automatically.
(1) Parameter
(a) Automatically adjusted parameter s
The following parameters are automatically adjusted by auto tuning.
Parameter No. Abbreviation Name
12 GD2 Ratio of load inertia moment to servo motor inertia moment
15 PG2 Position contr o l gain 2
16 VG2 Speed control gain 2
17 VIC Speed integral compensation
(b) Manually adjusted parameters
The following parameters are adjustable manually.
Parameter No. Abbreviation Name
13 PG1 Position contr o l gain 1
14 VG1 Speed control gain 1
(2) Adjustment procedure
Step Operation Description
1Choose the auto tuning mode 1 (parameter No. 8: 0001) and set the machine
resonance frequency of the response level to 15Hz 1 (parameter No. 9: 0001). Select th e auto tuning mode 1.
2During operation, increase the response level selection (parameter No. 9), and
return the setting if vibration occurs. Adjustment in auto tuning mode
1.
3Check the values of position control gain 1 (parameter No. 13) and speed control
gain 1 (parameter No. 14). Check the upper setting limits.
4 Choose the interpolation mode (parame ter No. 8: 0000). Select the interpolation mode.
5Using 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.
6Using 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.
7Looking 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 (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(puls e)
(b) Speed control gain 1 (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 setti ng 3