Mitsubishi Electric MR-J4, Instruction Manual

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17. FULLY CLOSED LOOP SYSTEM
17 - 18
(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).
ON
OFF
ON
OFF
LZ
(Encoder Z-phase pulse)
0 r/min
Stroke end
Linear encoder home position
Home position
Home position return speed
Creep speed
Home position return direction
Proximity dog
signal
Servo motor
speed
Reference home
position
Machine position
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
B A
Home position signal
A is recognized as
the on position.
B is recognized as
the on position.
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.