Machine Home Position Return Method - Mitsubishi Electric RD77MS2 User Manual

Machine home position return method

The method by which the machine home position is established (method for judging the home position and machine home
position return completion) is designated in the machine home position return according to the configuration and application of
the positioning method.
The following table shows the methods that can be used for this home position return method. (The home position return
method is one of the items set in the home position return parameters. It is set in "[Pr.43] Home position return method" of the
basic parameters for home position return.)
[Pr.43] Home position return
method
Near-point dog method
Count method 1
Count method 2
Data set method
Scale origin signal detection method
The following shows the signals used for machine home position return.
: Necessary, : Necessary as required, : Unnecessary
[Pr.43] Home position return
method
Near-point dog method
Count method 1
Count method 2
Data set method
Scale origin signal detection method
Creep speed
The stopping accuracy is poor when the machine suddenly stops from fast speeds. To improve the machine's
stopping accuracy, it is required to slow down the speed before it stops. This speed is set in the "[Pr.47] Creep
speed".
2 HOME POSITION RETURN CONTROL
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2.2 Machine Home Position Return
Operation details
Deceleration starts by the OFF  ON of the near-point dog. (Speed is reduced to "[Pr.47] Creep speed".)
The operation stops once after the near-point dog turns ON and then OFF. Later the operation restarts and then stops
at the first zero signal to complete the home position return.
That position is assumed as a home position.
The deceleration starts by the OFF  ON of the near-point dog, and the machine moves at the "[Pr.47] Creep speed".
The machine stops once after moving the distance set in the "[Pr.50] Setting for the movement amount after near-
point dog ON" from the OFF  ON position. Later the operation restarts and then stops at the first zero point to
complete the machine home position return.
The deceleration starts by the OFF  ON of the near-point dog, and the machine moves at the "[Pr.47] Creep speed.
The machine moves the distance set in the "[Pr.50] Setting for the movement amount after near-point dog ON" from
the near-point dog OFF  ON position, and stops at that position. The machine home position return is then regarded
as completed.
The position where the machine home position return has been performed becomes a home position.
The current feed value and feed machine value are overwritten to the home position address.
The machine moves in the opposite direction against of "[Pr.44] Home position return direction" at the "[Pr.46] Home
position return speed" by the OFF  ON of the near-point dog, and a deceleration stop is carried out once at the first
zero signal. Later the operation moves in direction of "[Pr.44] Home position return direction" at the "[Pr.47] Creep
speed", and then stops at the detected nearest zero point to complete the machine home position return.
Signals required for control
Near-point dog





Zero signal





Upper/lower limit




