APPX
Appendix 7 Processing Time
729
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.
*1 The standby system scan time is the total of "Execution time of the standby system program after a system switching cause is received
+ Tracking data reflection time".
*2 The systems may not be switched when the CC-Link IE Field Network module has not been mounted, when the extension base unit for
the redundant system is not being used, or depending on the state of the power supply module failure. To switch the systems regardless
of the state of the power supply module failure, mount the CC-Link IE Field Network module or use the extension base unit for the
redundant system. Note, in this case, that Trd is determined by the following:
Via the CC-Link IE Field Network module: Trd = 400ms (maximum) + Standby system scan time
Via the redundant extension base unit: Trd = 57.5ms (maximum)
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 1ms The following time is added
according to the parameter
setting and system
configuration.
• When the signal flow
memory is tracked: 0ms
• When the signal flow
memory is not tracked: 2ms
• When an extension base
unit for the redundant
system is used: 5.8ms
• When a fault occurs in the
extension cable: 2.5ms
• 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)
*5
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)
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Tracking data
reflection time
(Trc)
*4
5ms
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 730
Tracking data
reflection time
(Trc)
System switching request by 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
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