Overview Of The Absolute Position Detection System; Transmission Procedure For Absolute Position Signal - Mitsubishi Electric MELSEC iQ-F Series FX5 User Manual

Overview of the absolute position detection system

The detector comprises an encoder for the detection of position in one rotation in addition to the A, B, and Z phase signals for
the position control in normal operation and an accumulative revolution counter for the detection of the number of rotations.
The absolute position detection system detects the absolute position of the machine constantly and stores it with the backup
of the battery irrespective of the state of the power supply to the PLC system. Therefore, once the OP initial setting is
performed at the time of the installation of the machine, no OPR is required even when the power is turned on later. The
restoration of the system can be performed easily even when an instantaneous power failure or an emergency stop occurs.
In addition, because the absolute position data is backed up by a super capacitor in the detector, the absolute position data
will be hold for a specified time even if a cable is disconnected or broken.

Transmission procedure for absolute position signal

The following figure shows the overview of the absolute position signal transmission procedure between a servo amplifier and
a PLC system (CPU module, positioning module, and I/O modules).
For details on the communication between the servo amplifier and PLC system, refer to the manual for the servo amplifier
used.
Servo amplifier
Absolute position
detection request
Data transmission
Current position data
*1 CPU module input/output is also usable.
Errors during communication
• If a time-out occurs during communication, ABS transmission time out (Error code: 1949H) occurs.
• If transmission data causes a sum error, ABS transmission SUM (Error code: 194AH) occurs.
For corrective actions on errors, refer to the following.
Page 512 List of Error Codes
*1
I/O module
• Servo ON signal
• ABS transfer mode
• ABS request
• Ready to transmit
• ABS bit 0
• ABS bit 1
CPU module
[Special command] Current position data
G.ABRST1
G.ABRST2
12 CONTROL SUB FUNCTION
12.7 Absolute Position Restoration Function
Positioning module
[Md.20]
Current feed value
[Md.21]
Machine feed value
263
12