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7. GENERAL GAIN ADJUSTMENT
7.4 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
model control gains (PG1, VG1) which determ ine command trac kability are se t manually and the other
gains are set automatically.
(1) Parameter
PG1 and VG1 can be set manually bu t the follow ing parameter s are autom atically adjus ted by auto
tuning.
Parameter No. Abbreviation Name
34 GD2 Ratio of load inertia moment to servo motor inertia moment
35 PG2 Position con trol gain 2
37 VG2 Speed control gain 2
38 VIC Speed integral compensation
The following parameters are adjustable manually.
Parameter No. Abbreviation Name
6PG1Position control gain 1
36 VG1 Speed control gain 1
(2) Adjustment procedure
Step Operation Description
1 Set "010 " in param e ter No. 2. Select the auto tuning mode 1.
2During operation, increase the response level setting (parameter No. 2), and
return the setting if vibration occurs. Adjustment in auto tuning mode
1.
3 Check the values of PG1 (parameter No. 6) and VG1 (parameter No. 36). Check the upper setting limits.
4 Set "000 " in parameter No. 2. Select the interpolation mode.
5Using the PG1 value checked in step 3 as the guideline of the upper limit, set in
PG1 the value identical to the position loop gain of the axis to be interpolated. Set PG1.
6Using the VG1 value checked in step 3 as the guideline of the upper limit, look
at the rotation status and set in VG1 the value three or more times greater than
the PG1 setting. Set VG1.
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 (PG1: parameter No.6)
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) PG1 settingRotation speed (r/min) 131,072(pulse)
(b) Speed control gain 1 (VG1: parameter No. 36)
Set the response level of the speed loop of the model. Make setting using the following expression
as a guideline.
VG1 setting PG1 setting 3