Mitsubishi Electric MELSEC iQ-F Series User Manual page 26

Caution
• Detection of (the rear end and the front end of) the near-point dog will be affected by the input response time and the scan
time of the sequence program. Secure 1 scan time or more from the rear end of the near-point dog to turning ON of the
zero signal.
• Since the zero signal of the servo motor is used, adjust the relation between the rear end of the near-point dog and the zero
signal as shown in the following figure. If fine adjustment of the origin position is needed, adjust the position of the near-
point dog.
Longer than
1 scan time
Zero signal
• Properly set the near-point dog so that the near-point dog can be kept at the ON status until the speed is reduced to the
creep speed. Deceleration to the creep speed starts at the front end of the near-point dog, the operation stops at "the rear
end of the near-point dog" or at "detection of the first zero signal after the rear end of the near-point dog", and the current
address is cleared. If the speed is not reduced to the creep speed before detecting the rear end of the near-point dog, the
operation may not be stopped at the specified position.
• Use the near-point dog between the reverse rotation limit 1 (LSR) and the forward rotation limit 1 (LSF). The intended
operation may not be performed if the relationship among the near-point dog, reverse rotation limit 1 (LSR), and forward
rotation limit 1 (LSF) is not as shown in the figure below.
(Servo amplifier side)
Servo motor
• The creep speed should be sufficiently slow. Deceleration stop is not performed. For this reason, if the creep speed is not
slow enough, the operation may not be stopped at the specified position due to inertia.
• If the dog search function cannot detect the near-point dog signal, the speed will decelerate and the operation will stop. The
execution of the instruction ends with an error.
5 POSITIONING INSTRUCTION
78
5.3 Mechanical OPR
Rear end
Near-point DOG
Reverse Reverse
rotation limit 2 rotation limit 1
(CPU module side)
LSR
Operation in reverse rotation direction
Operation direction
Forward end
Near-point DOG
Forward
rotation limit 1 rotation limit 2
(CPU module side) (Servo amplifier side)
LSF
Operation in forward rotation direction
Forward