5. Spindle Adjustment
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(3) Adjusting the servo rigidity
The stopping position precision can be increased by raising the servo rigidity during orientation
stop.
1) Increase the SP001 (PGM) or SP002 (PGE) value to the degree that overshooting does not
occur during orientation stop.
2) Increase SP098 (VGOP) and SP099 (VGOI) by the same amount to the degree that vibration
does not occur.
3) The servo rigidity can be increased momentarily by increasing the SP100 (VGOD) value.
Increasing the SP100 value : Adverse effects may occur such as a drop in the torque in
respect to the position deflection, or an inconsistency in the
stopping position.
Setting the SP100 value to 0 : PI control will be applied. The servo rigidity will drop
momentarily, but the stopping position precision will increase.
• Speed loop delay compensation control and PI control
When stopping orientation for a normal tool change, etc., select delay/advance control.
However, if the spindle's frictional torque is large, and a precise stopping position is required,
select PI control. (SP100=0).
Examples of using PI control
• Positioning a workpiece with a lathe.
• Orientation of a machine which indexes a 5-plane machining attachment.
No. Abbr. Parameter name Details Setting range Standard
SP098 VGOP*
Speed loop gain
proportional term in
orientation mode
Set the speed loop proportional gain in orientation mode.
When the gain is increased, rigidity is improved in the
orientation stop but vibration and sound become larger.
0 to 1000 63
SP099 VGOI*
Speed loop gain integral
term in orientation mode
Set the speed loop integral gain in orientation mode. 0 to 1000 60
SP100 VGOD*
Speed loop gain delay
advance term in
orientation mode
Set a speed loop gain delay advance gain in orientation
mode.
When this parameter is set to "0", PI control is applied.
0 to 1000 15
POINT
1. If the forward run and reverse run stop positions differ even when using PI
control, the machine's backlash may be large. In this case, the stopping
precision may be improved by fixing the orientation rotation direction to one
direction. (Set with the spindle parameter SP097. bit 0, 1.)
2. If the gear ratio between the spindle and motor is large, the SP001, SP002
and SP006 values will be clamped internally even if changed, so it may not
be possible to set the required value. The parameter setting value will be
changed when these are clamped, but no changes will be visible in the
control.
CAUTION
If the spindle is mechanically locked during orientation stop, always input a
torque limit so that the motor's output torque is restricted. (Recommended
torque limit: 10% or less)
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