Execution Availability Of System Switching - Mitsubishi Electric MELSEC iQ-R Series User Manual

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
Redundant system status
Normal operation or continuation
error in the standby system
Tracking communications disabled
(cable disconnection)
Power-off, reset, hardware failure of
the CPU module of the standby
system
Stop error in WDT error
the standby
Error other than WDT
system
error
Network error detected in the standby
*1
system
During memory copy from control
system to standby system
During online program change
Operating status mismatch of the
CPU modules in both systems
During system switching
During online Redundant function
module module
change
Module on the main
base unit in a
redundant system
with redundant
extension base unit
Other modules
System switching disabled by the
DCONTSW instruction
*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 system switching cause is detected and the systems are switched. However, when an
online program 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 program 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 415 Files)
*6 Although the CPU module of the control system is switched to the standby system, the current standby system is not switched.
Execution availability of system switching
Automatic system switching
Power-off Hardware Stop error of the
or reset of failure of CPU module
the CPU the CPU
WDT
module module
error
  
*6 *6
  
*6 *6
  
*6 *6
  
*6
  
  
*6
  
  
  
  
*6 *6
  
  
  
  
Manual system switching
System System switching
switching request by the
request from SP.CONTSW
Error other
a network instruction
than WDT
*3
module
error
  
  
  
  
  
  
  
*2*5
  
  
  
  
  
  
  
System
switching
request from
*3
the engineering
*4
tool














26 REDUNDANT FUNCTION
26.2 System Switching
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