User`s manual

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MELSEC
APPENDIX
APPENDIX
Appendix 1 Communication with the Redundant CPU
This section explains communication with the Redundant CPU when the CC-Link
board is used.
(1) Access to the Redundant CPU
(a) Redundant CPU specify
To access the Redundant CPU, directly specify the station number of the
CC-Link module mounted on the station of the target Redundant CPU.
(b) Action to be taken at occurrence of system switching
After system switching, the Redundant CPU in the same system (control
system or standby system) can also be accessed by directly specifying the
station number that was specified before system switching.
1
1: When system switching occurs in the Redundant CPU system to be
accessed, the station number of the CC-Link module mounted on the
station of each Redundant CPU is also changed internally.
(Example) When the Redundant CPU in the control system is accessed
Before system switching
Tracking cable
Master station
Standby master station
Terminal resistor Terminal resistor
Station No. 0 Station No.1 Station No. 2
Local interface board
CC-Link
Standby
system
Control
system
After system switching
Tracking cable
Master station
Standby master station
Terminal resistor Terminal resistor
Station No. 1 Station No. 0 Station No. 2
Local interface board
CC-Link
Standby
system
Control
system
Control
system
Standby
system
POINT
Create a program to monitor which system in the redundant CPU system is
accessed from the CC-Link board.
• Indicates the CPU module operation status
• Remains ON/OFF even if the tracking cable is disconnected while the
redundant system is running.
SM1515
Control
system
Standby
system
At the time of TRK.CABLE ERR.(Error code:
6120) occurrence (System not determined.)
SM1515 ON OFF OFF
SM1516 OFF ON OFF
SM1516
Control/
Standby
system
status
APP