Mitsubishi MELDAS MDS-C1 Instruction Manual page 195

(4) Adjusting for feed forward control
In LMC compensation, a model position considering the position loop gain is calculated based on
the position command sent from the CNC, and compensation is carried out when the feed changes
to that direction. When the CNC carries out feed forward (fwd) control, overshooting equivalent to
the operation fraction unit occurs in the position commands, and the timing of the model position
direction change may be mistaken. As a result, the LMC compensation timing may deviate, or
compensation may be carried out twice or more.
If feed forward control is carried out and the compensation does not operate correctly, adjust with
the non-sensitive band (SV040 (LMCT)) during feed forward control. In this non-sensitive band
control, the overshooting set with LMCT is ignored during feed forward control. Instead the model
position direction change point is correctly recognized to correctly compensate LMC.
This parameter is meaningless when feed forward control is not being carried out.
<Adjustment method>
If the compensation timing deviates during feed forward control, increase the LMCT setting by 1µm
at a time.
Note that 2µm are set even when the LMCT is set to 0.
No. Abbrev. Parameter name
Lost motion
SV040 LMCT
compensation
non-sensitive band
4. Servo Adjustment
Set the non-sensitive band of the lost motion compensation in the feed
forward control.
When "0" is set, the actual value that is set is 2 µ m. Adjust by increasing by
1 µ m at a time.
4 - 24
Explanation Setting range
0 to 100
(µm)