YASKAWA SGD7S Product Manual page 343

 Operation When the Servo Is OFF
Backlash compensation is not applied when the servo is OFF (i.e., when power is not supplied
to motor). Therefore, the reference position POS is moved by only the backlash compensation
value.
The relationship between APOS and the motor shaft position is as follows:
• When servo is OFF: APOS = Servomotor shaft position
The following figure shows what happens when the servo is turned OFF after driving the Servo-
motor in the forward direction from target position TPOS0 to TPOS1. Backlash compensation
is not applied when the servo is OFF. (The SERVOPACK manages the position data so that
APOS and POS are the same.)
Target position
TPOS0
POS
APOS
Machine shaft
Pn231
Motor shaft
Machine shaft
Motor shaft
Backlash compensation value (Pn231)
 Operation When There Is Overtravel
When there is overtravel (i.e., when driving is prohibited due to an overtravel signal or software
limit), the operation is the same as for when the servo is OFF (
OFF on page 8-77), i.e., backlash compensation is not applied.
 Operation When Control Is Changed
Backlash compensation is performed only for position control.
Backlash compensation is not applied when position control is changed to any other control
method.
Backlash compensation is applied in the same way as when the servo is ON (
When the Servo Is ON on page 8-76) if any other control method is changed to position con-
trol.
Related Monitoring
You can monitor the following values on the operation monitor of the SigmaWin+.
Displayed Value
Input Reference Pulse Speed
Position Deviation
Input Reference Pulse
Counter
Feedback Pulse Counter
Fully-Closed Feedback Pulse
Counter
Feedback Pulse Counter
Servo OFF
Target position
TPOS1
Reference travel distance
Reference travel distance
Unit
Displays the input reference pulse speed before backlash
-1
min
compensation.
Displays the position deviation for the position reference
Reference units
after backlash compensation.
Displays the input reference pulse counter before back-
Reference units
lash compensation.
Displays the number of pulses from the actually driven
Encoder pulses
motor encoder.
External encoder Displays the number of pulses of the actually driven exter-
resolution nal encoder.
Displays the number of pulses from the actually driven
Reference units
encoder in reference units.
8.12 Additional Adjustment Functions
8.12.7 Backlash Compensation
Forward
reference
direction
Status with no backlash
compensation: POS = APOS

Operation When the Servo Is

Operation
Specification
8
8-77