Yaskawa Sigma-5 User Manual: Design and Maintenance - Rotary Motors - MECHATROLINK-II Communications Reference - Manual (Page 217)

5 Adjustments
5.8.6 Backlash Compensation Function
5-64
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.
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.
(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.
• The backlash compensation value is restricted by the following formula. The specified compensation
is not performed if this condition is not met.
∗ 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 -1 ],
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 -1
], external
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.
Pn231 ≤
Pn210
Pn20E
Maximum motor speed [min -1 ]
60
× × Encoder resolution × 0.00025
Pn233
Backlash compensation time constant
Classification
Setting Range Setting Unit Factory Setting When Enabled
0 to 65535 0.01 ms 0 Immediately Setup
Position
Un No. Displayed Information Unit
Un030 The current backlash compensation value 0.1 reference unit
Un031 Backlash compensation setting limit value 0.1 reference unit