Mitsubishi Electric MELDAS MDS-B-SVJ2 Series - Improvement of Protrusion at Quadrant Changeover

Chapter 5 Adjustment
5-16
5-3-4 Improvement of protrusion at quadrant changeover
The response delay (caused by non-sensitive band from friction, torsion, expansion/contraction,
backlash, etc.) caused when the machine advance direction reverses is compensated with the lost
motion compensation (LMC compensation) function.
With this, the protrusions that occur with the quadrant changeover in the DDB measurement method,
or the streaks that occur when the quadrant changes during circular cutting can be improved.
Circle cutting path before compensation Circle cutting path after compensation
(1) Lost motion compensation (LMC compensation)
The lost motion compensation compensates the response delay during the reversal by adding the
torque command set with the parameters when the speed direction changes. There are two
methods for lost motion compensation. With the MDS-B-SVJ2, type 2 is used as a standard.
(The explanation for type 1 method is omitted because it is interchangeable with the old method.)
<Setting method>
1. Set the servo function selection 1 (SV027:SSF1) bit 9. (The LMC compensation type 2 will start).
2. Set the compensation amount with a stall % (rated current % for the general-purpose motor) unit
in the lost motion compensation 1 (SV016:LMC1). The LMC1 setting value will be used for
compensation in the positive and negative directions when SV041:LMC2 is 0.
3. If the compensation amount is to be changed in the direction to be compensated, set LMC2. The
compensation direction setting will be as shown below with the CW/CCW setting in the CNC
parameter. If only one direction is to be compensated, set the side not to be compensated as -1.
No. Abbrev. Parameter name Explanation
SV027 SSF1 The lost motion compensation starts with the following parameter.
Servo function selection 1
F E D C B A 9 8 7 6 5 4 3 2 1 0
aflt zrn2 ovs lmc vfct
bit Explanation
8 00: Lost motion comp. stop 10: Lost motion comp. type 2
9
lmc
01: Lost motion comp. type 1 11: Setting prohibited
No. Abbrev. Parameter name Unit Explanation Setting range
SV016 LMC1 Lost motion
compensation 1
Stall % (rated
current %)
While measuring the quadrant protrusion amount, adjust
with a 5% unit.
The ± direction setting value will be applied when LMC2
is set to 0.
–1 ~ 200
SV041 LMC2 Lost motion
compensation 2
Stall % (rated
current %)
Set 0 as a standard.
Set this when the compensation amount is to be
changed according to the direction.
–1 ~ 200
Compensation
Cutting
direction
Compensation
point
CW CCW
A X axis: LMC2 X axis: LMC1
B Y axis: LMC1 Y axis: LMC2
C X axis: LMC1 X axis: LMC2
D Y axis: LMC2 Y axis: LMC1
+Y
-Y
+X
-X
A
The X axis command direc-
tion changes from + to –.
D
The Y axis command direc-
tion changes from + to –.
B
The Y axis command direc-
tion changes from – to +.
C
The X axis command direc-
tion changes from – to +.