Mitsubishi Electric MELDAS MDS-B-SVJ2 Series, Specifications And Instruction Manual

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Chapter 5 Adjustment
5-22
(2) Adjusting for feed forward control
Use OVS compensation type 2 if overshooting is a problem in contour cutting during feed forward
control.
If OVS compensation type 2 is used to attempt to compensate overshooting, the overshooting
may conversely become larger, or projections may appear during arc cutting. This is because
overshooting equivalent to the operation fraction unit occurs in the position commands when the
CNC is carrying out feed forward control. Because of this, the OVS compensation recognizes a
change in the command direction, and executes the compensation in the opposite direction.
If the compensation is in the opposite direction when carrying out feed forward control, adjust with
the non-sensitive band (SV040: LMCT) during feed forward control in the same way as during
LMC compensation. By ignoring overshooting of a set width in the LMCT or less, the command
direction change point is correctly recognized, and the OVS compensation is correctly executed.
Because this phenomenon is due to the same causes as the phenomenon during LMC
compensation, it is adjusted with the same parameters. The adjustment is completed if the correct
setting is possible during whichever compensation.
This parameter is insignificant when feed forward control is not used.
<Adjustment method>
If the OVS compensation is carried out in reverse during feed forward control, increase the LMCT
setting by 1
μ
m at a time.
Note that 2
μ
m are set even when the LMCT is set to 0.
POINT
OVS compensation type 2 is used if overshooting is a problem during feed
forward control.
No. Abbrev. Parameter name Explanation
SV027 SSF1 The overshooting 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
aft zrn2 ovs lmc vfct
bit Explanation
A 01: Overshooting comp. stop 10: Overshooting comp. type2
B
ovs
11: Overshooting comp. type 1 11: Setting prohibited
No. Abbrev.
Parameter
name
Unit Explanation Setting range
SV031 OVS1 Overshooting
compensation 1
Stall % (rated
current %) Increase the value by 1% at a time, and find the value where
overshooting does not occur. When OVS2 is set to 0, the
setting value will be applied in both the
±
directions.
–1 ~ 100
SV042 OVS2 Overshooting
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 ~ 100
SV040 LMCT Non-sensitive
band during feed
forward control
μ
m
This setting is valid only during feed forward control.
2
μ
m are set when the LMCT is set to 0. Adjust by raising
1
μ
m at a time.
0 ~ 100
POINT
1. When either parameter SV031: OVS1 or SV042: OVS2 is set to 0, the same
amount of compensation is carried out in both the positive and negative
direction, using the setting value of the other parameter (the parameter not
set to 0).
2. To compensate in only one direction, set -1 in the parameter (OVS1 or
OVS2) for the direction in which compensation is prohibited.
3. For contour cutting, the projection at the arc end point is compensated with
OVS compensation. LMC compensation is carried out at the arc starting
point.
Cutting direction
LMC compensation
OVS compensation