Home Position Return Mode; Outline Of Home Position Return - Mitsubishi Electric MELSERVO-J4 Series Instruction Manual

4. HOW TO USE THE POINT TABLE

4.4 Home position return mode

4.4.1 Outline of home position return

A home position return is performed to match the command coordinates with the machine coordinates.
Under the incremental method, every time switching on the input power supply, you have to perform the
home position return. Contrastingly, in the absolute position detection system, once you have performed the
home position return at machine installation, the current position will be retained even if the power supply is
shut off. Thereafter, the home position return is unnecessary when the power supply is switched on.
This section shows the home position return methods of the servo amplifier. Select the optimum method
according to the configuration and uses of the machine.
This servo amplifier has a home position return automatic retract function. When the machine stops on or
beyond the proximity dog, this function automatically backs the machine to the proper position and then
performs the home position return. Manually moving the machine by the JOG operation or others is
unnecessary.
Point
Before performing the home position return, make sure that the limit switch
operates.
Check the home position return direction. An incorrect setting will cause a
reverse running.
Check the input polarity of the proximity dog. Otherwise, it may cause an
unexpected operation.
In the following cases, make sure that the Z-phase has been passed through
once before performing a home position return.
When an incremental linear encoder is used in the linear servo motor control
mode
When an incremental external encoder is used in the fully closed loop control
mode
When a servo amplifier is used in the DD motor control mode
Z-phase unpassed will trigger [AL. 90.5 Home position return incomplete
warning].
For servo amplifiers with software version B6 or earlier, the dog type last Z-
phase reference home position return and the dogless Z-phase reference home
position return cannot be used in the following operation modes.
Fully closed loop control mode using an incremental linear encoder
Linear servo motor control mode using an incremental linear encoder
Direct drive motor control mode
Setting [Pr. PT04 Home position return type] to "_ _ _ 8" or "_ _ _ A" will trigger
[AL. 37 Parameter error].
For precautions for using linear servo motors or fully closed loop system, refer to
section 4.4.15 and 4.4.16.
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