Mitsubishi Electric MR-J4-_GF, Instruction Manual

Page: 87 / 274

6. SERVO MOTOR DRIVING
6 - 28
(e) Method -6 and -38 (dog type rear end reference home position return)
POINT
This home position return type depends on the timing of reading DOG (Proximity
dog) that has detected the rear end of the proximity dog. Therefore, when the
creep speed is set to 100 r/min and a home position return is performed, the
home position has an error of ± (Encoder resolution) × 100/65536 [pulse]. The
higher the creep speed, the greater the error of the home position.
The following figure shows the operation of Homing method -6. The operation direction of Homing
method -38 is opposite to that of Homing method -6.
Travel distance after proximity dog
+
Home position shift distance
Home position return speed
Creep speed
Proximity dog (Note)
Deceleration time
constant
Home position return
position data
Servo motor speed
Reverse
rotation
0 r/min
Forward
rotation
Statusword bit 10
Target reached
ON
OFF
ON
OFF
Statusword bit 12
Homing attained
ON
OFF
ON
OFF
Controlword bit 4
Homing operation start
DOG (Proximity dog)
Acceleration time
constant
10 ms or shorter
Note. After the front end of the proximity dog is detected, if the rear end of the proximity dog is detected without reaching the creep
speed, [AL. 90] occurs. Revise the length of the proximity dog or revise both the home position return speed and creep speed.
Servo motor speed
Reverse
rotation
0 r/min
Home position
return direction
Home position return start position
After retracting to before proximity dog,
the home position return starts from here.
Proximity dog
When a home position return is started from the proximity dog