YASKAWA SGD7S-****20A Series Product Manual page 354

8.12 Additional Adjustment Functions
8.12.8 Backlash Compensation
Important
 Backlash Compensation Time Constant
You can set a time constant for a first order lag filter for the backlash compensation value
(Pn231) that is added to the position reference.
If you set Pn233 (Backlash Compensation Time Constant) to 0, the first order lag filter is dis-
abled.
Pn233
Note: Changes to the settings are applied when there is no reference pulse input and the Servomotor is stopped.
The current operation is not affected if the setting is changed during Servomotor operation.
Related Monitoring
You can monitor the following values on the operation monitor of the SigmaWin+.
Current Backlash Compensation Value
Backlash Compensation Value Setting Limit
Compensation Operation
This section describes the operation that is performed for backlash compensation.
Note: The following figures are for when backlash compensation is applied to references in the forward direction
(Pn230 = n.0). The following monitor information is provided in the figures: TPOS (target position in the
reference coordinate system), POS (reference position in the reference coordinate system), and APOS (feed-
back position in the machine coordinate system). The monitor information includes the feedback position in
machine coordinate system (APOS) and other feedback information.
The backlash compensation value is subtracted from the feedback positions in the monitor information, so it
is not necessary for the host controller to consider the backlash compensation value.
8-76
• The backlash compensation value is restricted by the following formula. Backlash compensa-
tion is not performed if this condition is not met.
Maximum motor peed [min
Pn210

Pn2 1 ≤
Pn20E
*
Refer to the following section for the encoder resolution.
5.15 Electronic Gear Settings on page 5-42
With fully-closed loop control, substitute the number of external encoder pulses per motor rotation
for the encoder resolution in the above formula.
Example 1:
Pn20E = 4, Pn210 = 1, Maximum motor speed = 6,000 [min
16,777,216 (24 bits)
1/4 × 6,000/60 × 16,777,216 × 0.00025 = 104,857.6 [reference units]
 The backlash compensation will be limited to 104,857.6 reference units.
Example 2:
Pn20E = 4, Pn210 = 1, Maximum motor speed = 6,000 [min
Scale Pitches (Pn20A) = 500, and Use of the JZDP-H00-000 (signal resolution: 1/256):
1/4 × 6,000/60 × (500 × 256) × 0.00025 = 800.0 [reference units]
 The backlash compensation will be limited to 800.0 reference units.
• Do not exceed the upper limit of the backlash compensation value. You can check the upper
limit on the operation monitor of the SigmaWin+.
Backlash Compensation Time Constant
Setting Range
0 to 65,535
Displayed Value
-1 ]
 Encoder re olution*  0.00025
60
Setting Unit Default Setting
0.01 ms 0
Setting Unit
0.1 reference units
0.1 reference units
-1
], and Encoder resolution =
-1
], Number of External Encoder
Position
When Enabled Classification
Immediately Setup