37 FUNCTIONS
37.1 System Switching
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37
37.1
System Switching
This function switches the systems between the control system and the standby system to continue operation of the
redundant system when a failure or an error occurs in the control system. The systems can also be switched manually by a
user for debugging or maintenance.
System switching method
The following two methods are available for system switching: automatic system switching (automatically performed by a
system) and manual system switching (performed by a user).
The following table lists the system switching types, causes, and priority of when multiple causes are simultaneously
generated.
• When multiple system switching causes are simultaneously generated, the systems are switched according to the cause
with higher priority. The switching cause determined according to the priority is stored in the event history and SD1643
(System switching cause).
• The manual system switching is requested for the control system CPU module.
The systems are not switched even when the CPU module is set to the STOP state. They are switched when
any of the above system switching causes is generated.
System switching type
System switching cause
Priority
Automatic system switching
Power-off, reset, hardware failure of the CPU module
High
Low
1
Stop error of the CPU module
2
System switching request from a network module
3
Manual system switching
System switching request by the SP.CONTSW instruction
4
System switching request from the engineering tool
5
Summary of Contents for MELSEC iQ-R-R00CPU
Page 2: ......
Page 151: ...9 MONITOR FUNCTION 9 1 Real Time Monitor Function 149 9 MEMO ...
Page 323: ...18 SEQUENCE SCAN SYNCHRONIZATION SAMPLING FUNCTION 321 18 MEMO ...
Page 330: ...328 20 ROUTING SETTING 20 3 Precautions MEMO ...
Page 423: ...26 BASIC CONCEPT 26 8 State Transition of the Redundant System 421 26 MEMO ...
Page 1014: ...1012 APPX Appendix 15 Added and Enhanced Functions MEMO ...
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