YASKAWA SGMJV User Manual page 221

5 Adjustments
5.8.6 Backlash Compensation Function
• The encoder output pulse will output the number of encoder pulses for which driving was actually per-
formed, including the backlash compensation value. If using the encoder output pulse for position feed-
back at the host controller, must consider the backlash compensation value.
 When Servo is ON
The backlash compensation value (Pn231) is added in the compensation direction when the servo is ON (i.e.,
the servomotor is powered) and a reference is input in the same direction as the backlash compensation direc-
tion (Pn230.0). If there is a reference input in the direction opposite to the backlash compensation direction,
the backlash compensation value is not added (i.e., backlash compensation is not performed).
The relationship between APOS and the servomotor shaft position is as follows:
• If a reference is input in the compensation direction: APOS = Motor shaft position - Pn231
• If a reference is input in the direction opposite to the compensation direction: APOS = Motor shaft position
The following figure shows driving the servomotor in the forward direction from target position TPOS0 to
TPOS1 and then to TPOS2, and then returning from TPOS2 to TPOS1 and then to TPOS0.
Backlash compensation is applied when moving from TPOS0 to TPOS1, but not when moving from TPOS2 to
TPOS1.
If a reference is input
in the compensation
direction
If a reference is input
in the direction opposite
to the compensation direction
5-66
Servo ON
Target position
TPOS0
Travel distance
POS
APOS
Machine axis
Pn231
Motor axis
Machine axis
Motor axis
Backlash (= Pn231)
Travel distance
POS
APOS
Machine axis
Travel distance
Motor axis
Machine axis
Motor axis
CAUTION
Target position
TPOS1
Travel distance
Travel distance Travel distance
Travel distance
Travel distance
Target position
TPOS2
Pn231
Backlash (= Pn231)