MITSUBISHI ELECTRIC MOTION CONTROLLERS Q172DCPU - Manual (Page 99)

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4 AUXILIARY AND APPLIED FUNCTIONS
4.2 Absolute Position System
The positioning control for absolute position system can be performed using the
absolute-position-compatible servomotors and servo amplifiers.
If the machine position is set at the system starting, home position return is not
necessary because the absolute position is detected at the power on.
The machine position is set with the home position return using the Motion SFC
program or MT Developer.
(1) Conditions of the absolute position system start
Perform a home position return after machine adjustment at the absolute position
system start.
(2) In the absolute positioning system, the absolute position may be lost in the
following cases:
Set the absolute position with a home position return.
(a) The battery unit is removed or replaced.
(b) The battery error of the servo amplifier occurs. (It is detected at the servo
amplifier power on).
(c) The machine system is disturbed by a shock.
(d) The cable between servo amplifier and encoder is removed, or the servo
amplifier or encoder is replaced.
(3) The current value history can be monitored using of the "System setting mode-
allowable travel during power off" or "Monitor mode" using a MT Developer.
(Refer to the help of MT Developer to be used "Allowable travel during power off"
and "Monitor mode".)
CAUTION
After removing or replacing the battery unit, correctly install the new unit and set the absolute
position.
After a servo battery error occurs, eliminate the cause of the error and ensure operation is safe
before setting the absolute position.
After the mechanical system is disturbed by a shock, make the necessary checks and repairs,
and ensure operation is safe before setting the absolute position.