YASKAWA SGMJV User Manual page 220

• The backlash compensation value is restricted by the following formula. The specified compensation
is not performed if this condition is not met.
Pn210
≤
Pn231
Pn20E
∗
For details on encoder resolution, refer to 8.3.5 Electronic Gear. With fully-closed loop control, substitute
the number of external encoder pulses per motor revolution for "encoder resolution" in the formula above.
Example 1:
Assuming Pn20E = 4, Pn210 = 1, maximum motor speed = 6000 [min
encoder resolution = 1048576 (20 bits):
1/4 × 6000/60 × 1048576 × 0.00025 = 6553.6 [reference units]
The upper limit for the backlash compensation is 6553.6 [reference units].
Example 2:
When using the conditions Pn20E = 4, Pn210 = 1, maximum motor speed = 6000 [min
encoder pitch count (Pn20A) = 500, JZDP-D00-000 (signal resolution: 1/256):
1/4 × 6000/60 × (500 × 256) × 0.00025 = 800.0 [reference units]
 The upper limit for the backlash compensation is 800.0 [reference units].
• Do not exceed the upper limit of the backlash compensation value. The upper limit of the backlash
compensation value can be confirmed in Un031.
 Backlash Compensation Time Constant
Set a time constant for a first order lag filter to use when adding the backlash compensation value (Pn231) to
the position reference.
If you set Pn233 to 0, the first order lag filter is disabled.
Backlash compensation time constant
Pn233
Setting Range
0 to 65535
Note: Changes to the set value are applied when there is no position reference input and the servomotor is stopped. The
current operation is not affected if the set value is changed during servomotor operation.
(3) Related Monitor
The following monitoring parameters provide information on backlash compensation.
Un No.
Un030
Un031
(4) Compensation Operation
This section describes the operation that is performed for backlash compensation.
Note: The following figures are for when backlash compensation is applied for references in the forward direction
(Pn230.0 = 0). The following monitoring information is provided in the figures: TPOS (target position in the refer-
ence coordinate system), POS (reference position in the reference coordinate system), and APOS (feedback position
in the machine coordinate system). The monitoring information includes the feedback position in machine coordi-
nate system (APOS) and other feedback information. The backlash compensation value is subtracted from the feed-
back positions in the monitoring information, so it is not necessary for the host controller to consider the backlash
compensation value.
Maximum motor speed [min
×
60
Setting Unit
0.01 ms
Displayed Information
The current backlash compensation value
Backlash compensation setting limit value
5.8 Additional Adjustment Function
-1
]
× Encoder resolution × 0.00025
-1
],
Position
Factory Setting When Enabled
0 Immediately
-1
], external
Classification
Setup
Unit
0.1 reference unit
0.1 reference unit
5
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