Mitsubishi Electric RD77MS2 User Manual page 40

Precautions during operation
• The error "Count method movement amount fault" (error code: 1944H) will occur if the "[Pr.50] Setting for the movement
amount after near-point dog ON" is smaller than the deceleration distance from the "[Pr.46] Home position return speed" to
"[Pr.47] Creep speed".
• If the speed is changed to a speed faster than "[Pr.46] Home position return speed" by the speed change function
(Page 248 Speed change function) during a machine home position return, the distance to decelerate to "[Pr.47] Creep
speed" may not be ensured, depending on the setting value of "[Pr.50] Setting for the movement amount after near-point
dog ON". In this case, the error "Count method movement amount fault" (error code: 1944H) occurs and the machine home
position return is stopped.
• The following shows the operation when a machine home position return is started while the near-point dog is ON.
■Operation when a machine home position return is started at the near-point dog ON position
4.
3.
OFF
Near-point dog
Zero signal
1.
A machine home position return is started.
2.
The machine moves at the home position return speed in the opposite direction of a home position return.
3.
Deceleration processing is carried out when the near-point dog OFF is detected.
4.
After the machine stops, a machine home position return is carried out in the home position return direction.
5.
The machine home position return is completed on detection of the first zero signal after the travel of the movement
amount set to "[Pr.50] Setting for the movement amount after near-point dog ON" on detection of the near-point dog
signal ON.
• Turn OFF the near-point dog at a sufficient distance from the Home position. Although there is no harm in operation if the
near-point dog is turned OFF during a machine home position return, it is recommended to leave a sufficient distance from
the home position when the near-point dog is turned OFF for the following reason.
If the machine home position return is performed consecutively after the near-point dog is turned OFF at the time of machine home position return completion,
operation will be performed at the home position return speed until the hardware stroke limit (upper/lower limit) is reached. If a sufficient distance cannot be
kept, consider the use of the home position return retry function.
• When the stop signal stops the machine home position return, carry out the machine home position return again. When
restart command is turned ON after the stop signal stops the home position return, the error "Home position return restart
not possible" (error code: 1946H) will occur.
• After the home position return has been started, the zero point of the encoder must be passed at least once before point A
is reached. However, if selecting "1: Not need to pass servo motor Z-phase after power on" with "Function selection C-4
(PC17)", it is possible to carry out the home position return without passing the zero point.
2 HOME POSITION RETURN CONTROL
38
2.2 Machine Home Position Return
[Pr.50] Setting for the movement amount
after near-point dog ON
1. 5.
2.
ON