Redundant Function Processing Time - Mitsubishi Electric MELSEC iQ-R Series User Manual

Redundant function processing time

This section describes the processing time in the redundant function.
Increase in the scan time due to tracking transfer
The following describes the increase in the scan time of the CPU module due to tracking transfer.
The increase in the scan time determined by the following calculation formula is a rough standard for a system start-up. Check
the increase in the scan time with the actual systems.
The scan time can be checked in SD520 and SD521 (Current scan time). ( Page 684 Fixed scan function
information)
Item
Increase in the scan time of the
CPU module in the control
system (Ts)
Increase in the scan time of the
CPU module in the standby
system (Tsb)
Ex.
When CTRL is a control system execution program and MAIN is a program executed in both systems (in configuration with
the main base unit only
END
processing
Tca
Control system
CPU module
Data reception
completion
Standby system
CPU module
*1 If the constant scan is used, waiting time for the constant scan is generated.
*2 In a redundant system with redundant extension base unit, the processing order in the scan is different ( Page 81 In redundant
mode), but the operation is the same as in a configuration with the main base unit only.
APPX
724
Appendix 7 Processing Time
Increase in the scan time
Ts = Twr + Tst + Tca +  [ms]
Tsb = Taw + Trc +  [ms]
*2
)
Scan time of the control system CPU module
I/O
MAIN, CTRL
*1
refresh
Update
completion
I/O
Trc
refresh
END processing
Reference
Twr: Page 725 Waiting time for completion of the previous tracking data reflection (Twr)
Tst: Page 725 Tracking data send time (Tst)
Tca: Page 726 Waiting time for completion of tracking data reception (Tca)
: Page 727 Other extended times ()
Taw: Page 727 Waiting time for tracking data reception (Taw)
Trc: Page 728 Tracking data reflection time (Trc)
: Page 728 Other extended times ()
END processing
Ts
Twr Tst
Tracking data
MAIN Taw
Scan time of the standby system CPU module
Tca
*1
Data reception
completion
Trc
Tsb
END processing
I/O
refresh
Update
completion