Mitsubishi MELDAS MDS-C1

4. Servo Adjustment
4 - 20
4-3-5 Improvement of protrusion at quadrant changeover
The response delay (caused by dead 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 at the quadrant changeover in the DBB measurement method, or
the streaks that occur when the quadrant changes during circular cutting can be improved.
(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 types
of LMC compensation. Type 2 is the standard method. (Type 1 is for compatibility with older
models, and thus explanations have been omitted.)
<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 NC parameter.
If only one direction is to be compensated, set the side not to be compensated as -1.
No. Abbrev. Parameter name Explanation Setting range
SV016 LMC1
Lost motion
compensation 1
Set the compensation amount based on the stall (rated) current of the
motor.
The standard setting is double of the friction torque. Setting to "0" means
the compensation amount is zero.
-1 to 200
(Stall [rated]
current %)
SV041 LMC2
Lost motion
compensation 2
Set this with SV016 (LMC1) only when you wish to set the lost motion
compensation amount to be different depending on the command
directions.
Set to "0" as a standard.
-1 to 200
(Stall [rated]
current %)
SV027 SSF1 Servo function
selection 1 F E D C B A 9 8 7 6 5 4 3 2 1 0
aflt zrn2 afse ovs lmc omr zrn3 vfct upc vcnt
bit Meaning when "0" is set Meaning when "1" is set
8 Set the compensation amount with SV016 (LMC1) and SV041 (LMC2).
9
lmc
00: Lost motion compensation stop 10: Lost motion compensation type 2
01: Lost motion compensation type
1
11: Setting prohibited
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 +.
DBB: Double Ball Ba
r
Circle cutting path after compensationCircle cutting path before compensation