Mitsubishi Electric MELSERVO-J5 MR-J5-G Series, User Manual

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12 USING A FULLY CLOSED LOOP SYSTEM
12.5 Basic functions
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12
Reference home position
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Absolute position linear encoder
The reference home position for an absolute position linear encoder is every position per servo motor revolution starting from
the linear encoder home position (absolute position data = 0).
In the case of Method -1 (dog type homing), the nearest position after the proximity dog signal turned off is the home position.
The linear encoder home position can be set to any position.
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Incremental linear encoder
Precautions
• To execute homing securely, start homing after moving the servo motor to the opposite stroke end with the JOG operation
from the controller or other methods.
• If the linear encoder home position (reference mark) does not exist on the incremental linear encoder, only the homing
methods that do not use the Z-phase can be executed.
• Do not set multiple homing positions (reference marks).
• An interval for turning on home position (reference mark) signal of the linear encoder has a certain width.
(Specifications differ depending on the linear encoder.)
Example: When the Z-phase is recognized at startup
The position where the signal turns on depends on the direction in which the home position is passed through. In a case
where homing is always required to be completed at the same position (such as dog type homing), start homing with the same
direction.
The reference home position for an incremental linear encoder is every position per servo motor revolution starting from the
first linear encoder home position which has been passed through after the power-on. (reference mark).
In the case of Method -1 (dog type homing), the nearest reference home position after the proximity dog signal rear end is
detected is the home position.
ON
OFF
0 r/min
Linear encoder home position Home position
Homing speed
Creep speed
Homing direction
Proximity dog signal
Servo motor speed
Reference home position
Machine position
Equivalent to one servo motor revolution
B A
Home position signal
A is recognized as
the ON position
B is recognized as the ON position