9.12 Additional Adjustment Functions
9.12.8 Backlash Compensation
9-73
9
T
uning
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.
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 motor operation.
Related Monitoring
You can monitor the following values on the operation monitor of the S.
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:
target position
(607Ah) (tar-
get position in the reference coordinate system),
position demand value
(6062h) (reference position in the ref-
erence coordinate system), and
position actual value
(6064h) (feedback position in the machine coordinate
system). The monitor information includes the feedback position in machine coordinate system (
position
actual value
) and other feedback information. The backlash compensation value is subtracted from the feed-
back positions in the monitor information, so it is not necessary for the host controller to consider the back-
lash compensation value.
•
The backlash compensation value is restricted by the following formula. Backlash compensa-
tion is not performed if this condition is not met.
*
Refer to the following section for the encoder resolution.
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:
Denominator = 1, Numerator = 1, Maximum motor speed = 6,000 [min
-1
], and Encoder resolu-
tion = 16,777,216 (24 bits)
1/1
×
1/16
×
6,000/60
×
16,777,216
×
0.00025 = 26,214.4 [reference units]
The backlash compensation will be limited to 26,214.4 reference units.
Example 2:
Denominator = 1, Numerator = 1, Maximum motor speed = 6,000 [min
-1
], number of external
encoder 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 S.
Pn233
(2233h)
Backlash Compensation Time Constant
Setting Range
Setting Unit
Default Setting
When Enabled
Classification
0 to 65,535
0.01 ms
0
Immediately
Setup
Displayed Value
Setting Unit
Current Backlash Compensation Value
0.1 reference units
Backlash Compensation Value Setting Limit
0.1 reference units
Important
Pn231 ≤
Denominator
Numerator
60
Pn210
Pn20E
Maximum motor speed [min
-1
]
Encoder resolution
*
0.00025
Position