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35 BASIC CONCEPT
35.9 State Transition of a System Using the SIL2 Process CPU
35.9 State Transition of a System Using the SIL2
Process CPU
The following figure shows the state transition of the system after start-up.
*1 When both systems are powered off, both systems enter the power-off state regardless of the system type.
System A: Off
System B: Off
Backup mode
System A: Off
System B: Control system
System A: Control system
System B: Standby system
System A: Standby system
System B: Control system
System A is powered off.
(Systems are switched.)
System A: Control system
System B: Off
System A is powered off. System A is powered on. System switching
System B is powered off.
System B is powered on.
Both systems are
powered on.
Both systems are powered off.
*1
System B is powered on.
(Forced start of the control system)
System A is powered on.
(Forced start of the control system)
System B is powered off.
(Systems are switched.)