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5.5 Tracking Function
5.5.7 Tracking Mode
5
(2) Synchronized Tracking Mode
This method performs tracking to the standby system for each scan while the control
system CPU module is executing the END processings.
If the previous tracking is not complete during END processing, the system will wait
and perform the next tracking after it has been completed.
2 types of synchronized tracking modes are available: synchronized tracking mode
and program priority mode.
The default tracking mode is synchronized tracking mode.
Change the tracking mode settings at the tracking settings in the redundant
parameter settings.
(a) Synchronized Tracking Mode
In synchronized tracking mode, the control system CPU stands from tracking start
to finish, and executes the scan execution type program upon tracking
completion.
For this reason, when system switching occurs, the new control system CPU
starts operation based on the scan tracking data of up to 1 scan before
However, scan time increases by the amount of tracking time.
Diagram 5.52 Synchronized Tracking Mode Operation Timing
Send
Receive
Send
Receive
Control system
CPU module
END
Run
program 1)
END
END
Non - executed
0
0
0
Run
program 2)
Waiting 1)
Waiting 2)
Scan time
Error occurrence
Adjust Tracking data 1)
Adjust Tracking data 2)
Because tracking processing 2) is
complete, adjust tracking data 2) will be
performed to reflect the change in the
new control system CPU module's
internal device.
Tracking processing 1)
Tracking processing 2)
Prepare Tracking data 1)
Prepare Tracking data 2)
Run program
New Standby system
CPU module
Standby system
CPU module
New Control system
CPU module