Mitsubishi MR-J4-10A Instruction Manual page 577

17. FULLY CLOSED LOOP SYSTEM
(b) Home position return using incremental linear encoder
When you use an incremental linear encoder, LZ (Encoder Z-phase pulse) from the servo amplifier
will be the home position (reference mark) of the linear encoder. Two or more home positions
(reference marks) should not be set. In addition, the home position return cannot be executed
without home position (reference mark).
1) Caution for passing the home position (reference mark)
An interval for turning on home position (reference mark) signal of the linear encoder has a
certain width. (Specifications differ depending on the linear encoders. For details, refer to "Linear
Encoder Instruction Manual".)
Example: When Z-phase is recognized at startup
The position which turns on a signal differs depending on the directions of home position passing.
When you need to set the home position return completion to the same position each time such
as dog type home position return, always start home position return with the same direction.
2) Caution for linear encoder which does not have the home position (Z-phase)
The linear encoder which does not have the home position (Z-phase), LZ (Encoder Z-phase
pulse) of the servo amplifier does not be outputted. The home position return can be performed
depending on specifications of controllers even if LZ (Encoder Z-phase pulse) is not outputted.
Check the controller specifications of the home position return.
Servo motor
speed
0 r/min
Proximity dog
ON
signal
OFF
ON
LZ
OFF
(Encoder Z-phase pulse)
Reference home
position
Machine position
Home position signal
A is recognized as
the on position.
Home position return direction
Home position return speed
B A
B is recognized as
the on position.
17 - 18
Creep speed
Stroke end
Home position
Linear encoder home position