Mitsubishi Electric MELSEC iQ-R-R04CPU - Execution Availability of System Switching

28 FUNCTIONS
28.2 System Switching
447
28
Execution availability of system switching
The following tables show the execution availability of system switching in each operation mode.
In backup mode
: Switching possible, : Switching not possible
*1 When the group specification has been set in the standby system, a network error is not detected if communication is available with the
line of an Ethernet-equipped module after a communication error has occurred on the other Ethernet-equipped module. ( MELSEC
iQ-R Ethernet User's Manual (Application))
*2 After the online change has been completed, the switching cause is detected and the systems are switched. However, when an online
change is being executed only in the standby system, the systems cannot be switched.
*3 If system switching is disabled when a system switching request is sent, a continuation error occurs and a cause of a system switching
failure is stored in SD1644 (Cause of system switching failure).
*4 If system switching is disabled when a system switching request is sent, the error code corresponding to a cause of the system
switching failure is returned.
*5 When the systems are switched during an online change, a mismatch between the files is detected in the system consistency check and
a stop error may occur on the new standby system. ( Page 477 File)
*6 Although the control system CPU module is switched to the standby system CPU module, the existing standby system is not switched.
Redundant system status Execution availability of system switching
Automatic system switching Manual system switching
Power-off or
reset of the
CPU
module
Hardware
failure of
the CPU
module
Stop error of the CPU
module
System
switching
request
from a
network
module
*3
System
switching
request by
the
SP.CONTSW
instruction
*3
System
switching
request
from the
engineering
tool
*4
WDT error Error other
than WDT
error
Normal operation or continuation
error in the standby system
 
Tracking communications
disabled (cable disconnection)

*6

*6
  
Power-off, reset, hardware
failure of the standby system
CPU module

*6

*6
  
Stop error in
the standby
system
WDT error 
*6

*6
  
Error other
than WDT
error

*6
  
Network error detected in the
standby system
*1
 
During memory copy from
control system to standby
system

*6
  
During online change 
*2*5

Mismatch between the CPU
module operating status of both
systems
 
During system switching  
During online
module
change
Redundant
module

*6

*6
  
Other modules  
System switching disabled by the
DCONTSW instruction
 