APPX
Appendix 9 Processing Time
931
A
Time required for system switching
The following describes the time required for the CPU module in the new control system to start operating as the new control
system after the detection of a system switching cause in the control system.
The time required for system switching determined by the following calculation formula is a rough standard for a system start-
up. Check the time with the actual systems.
Tsw = Trd + Trc + Tcs [ms]
• Tsw: Time required for system switching
*1
• Trd: Delay until the CPU module in the standby system receives the system switching request sent from the control system
• Trc: Time required for reflection of tracking data in the CPU module of the standby system
• Tcs: Setup time required for the CPU module in the standby system to start operating as the new control system
*1 This is the maximum system switching time.
System switching
cause
Processing time per each system switching cause
Trd Trc Tcs
• Power supply module
failure
*2
, power-off
•Reset
■When the standby system scan time is longer
than 19.26ms
*1
0.517 + Standby system scan time - 19.26 [ms]
■When the standby system scan time is 19.26ms
or shorter
*1
0.517ms
0ms • Process CPU
(redundant mode): 1ms
• SIL2 Process CPU:
4ms
The following time is
added according to the
parameter setting.
When the signal flow
memory is tracked: 0ms
When the signal flow
memory is not tracked:
2ms
• CPU module failure
• Base unit failure
*3
• CPU module stop error
(major)
• Redundant function
module failure
*3
■When the standby system scan time is longer
than 10ms
*1
0.517 + Standby system scan time - 10 [ms]
■When the standby system scan time is 10ms or
shorter
*1
0.517ms
CPU module stop error
(moderate)
Increase in the scan time of the CPU module in the
control system (Ts) by tracking transfer
*4
- Waiting
time for completion of the previous tracking data
reflection (Twr)
Page 932
Tracking data
reflection time
*4
• Process CPU
(redundant mode): 5ms
• SIL2 Process CPU:
8ms
System switching request
from a network module
Increase in the scan time of the CPU module in the
control system (Ts) by tracking transfer - Waiting
time for completion of the previous tracking data
reflection (Twr)
Page 932
Tracking data
reflection time
System switching request by
using the SP.CONTSW
instruction
System switching request
from the engineering tool
Trd
Trc Tcs
Tsw
Cause of system switching has been detected.
Control system
Control system
Standby system
Standby system
System A
System B
To Next Page
Loading...
