Mitsubishi Electric MELSEC iQ-R RD75P4, User Manual

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7 CONTROL SUB FUNCTIONS
7.7 Absolute Position Restoration Function
7.7
Absolute Position Restoration Function
Absolute position restoration function restores the absolute position of the specified axis using the absolute position detection
system. When this function is used, the OPR after power off due to an instantaneous power failure and emergency stop is not
required, and the restoration operation at site can be performed easily.
Configuration and preparation of the absolute position detection
system
Configuration
The following figure shows the configuration of the absolute position detection system.
Preparation
Prepare the absolute position detection system with caution by referring to the following descriptions.
CAUTION
An absolute position restoration by the positioning function may turn off Servo ON signal (servo off) for approximately 60ms
+ scan time, and the motor may run unexpectedly. If this causes a problem, provide an electromagnetic brake to lock the
motor during absolute position restoration.
Component Description
(1) Servo amplifier • Use a Mitsubishi General-Purpose AC Servo which has an absolute position detection function (absolute position
data transfer protocol) equivalent to that of MR-J3-  A).
• Install the battery to the servo amplifier.
• Validate the absolute position detection function of the servo amplifier.
For details, refer to the manual for the servo amplifier used.
(2) Servomotor • Use a servomotor with absolute position detector.
For details, refer to the manual for the servo motor used.
(3) Encoder cable • Add a battery power connection cable (BAT/LG signal) to the incremental encoder cable connection.
For details, refer to the manual for the cable used.
(4) Programmable controller system • Establish the communications of absolute position detection data using I/O modules (three input points /three
output points).
• Use I/O modules with any number of points.
• Allocating the three input signals in serial order facilitates the control with a program. This also applies to the three
output signals.
(1)
(2)
(3)
(4)
RD75
Servo
amplifier
Power
supply
CPU module I/O module
Programmable controller system
Absolute position holding battery
Encoder cable
Control signal connector
Servomotor with absolute position detector
Control
panel