Mitsubishi Electric MELSEC iQ-R16MTCPU Programming Manual page 406

• If executing home position return with a fully closed loop control servo amplifier (MR-J3-B-RJ006, MR-J4-B), do not
change fully closed loop control/semi closed loop control during home position return operation. When fully closed loop
control/semi closed loop control is changed during home position return operation, the home position return might not be
completed normally
• If performing home position return from zero point, depending on the actual motor position at the start, and it's relative
position to zero point, the home position return might be completed at the next zero point. It is recommended to move the
start of the home position return from the zero point to a position in the reverse direction of home position return direction.
• The operation for when home position return is executed during the operation of amplifier-less operation function is shown
below.
Servo amplifier
MR-J3(W)-B
MR-J4(W)-B
• The following describes precautions for the home position return operations for the home position return by dogless home
position signal reference method.
Home position
return operation
Operation A
Operation B
Operation C
5 POSITIONING CONTROL
404
5.21 Home Position Return
Operation
Regardless of the servo amplifier model, home position return is executed by the home position return operation of "Operation B".
Home position return is performed by the home position return operation that complies with the amplifier operation mode that is set
in [Motion CPU Common Parameter]  [Servo Network Setting]  "Amplifier Setting".
Cautions
• Set the servo parameter (expansion parameter) "Function selection C-4 (PC17)" to "0: Need to pass motor Z phase after the
power supply is switched on". If set to "1: Not need to pass motor Z phase after the power supply is switched on", when home
position return by dogless home position signal reference method (operation A) is started, a minor error (error code: 1978H) will
occur and the home position return is not executed.
• If the "[St.1066] Zero pass (R: M32406+32n/Q: M2046+20n)" was on at home position return start, this signal turns off once at the
home position return start and turns on again at the next zero point passage.
• If an external limit switch is detected during a deceleration stop after zero point detection, an error occurs and stops. Ensure there
is enough distance between the zero point signal and external limit switch, or set the deceleration time so the decelerating
distance is shortened.
• With home position return retry function valid, if zero point is detected during a deceleration stop after external limit switch is
detected, an error occurs and stops. Set the external limit switch in a position that puts the zero signal inside the external limit
switch.
• Set the servo parameter (expansion parameter) "Function selection C-4 (PC17)" to "1: Not need to pass motor Z phase after the
power supply is switched on". If set to "0: Need to pass motor Z phase after the power supply is switched on", when home
position return by dogless home position signal reference method (operation B) is started, a minor error (error code: 1978H) will
occur and the home position return is not executed.
• Home position return retry function cannot be used.
• If an external limit switch is detected during home position return operation, an error occurs and stops.
• Home position return retry function cannot be used.