Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual page 414

The system waiting for the start-up of the other system
When the Process CPU (redundant mode) is started up and tracking communications cannot be established with the other
system, the CPU module will start waiting for the start-up of the other system in three seconds.
Both of the CTRL LED and SBY LED of the redundant function module turn off because the system of the CPU module is not
the control system or standby system yet. The BACKUP LED flashes because a system switching disable cause has been
generated.
After tracking communications are established with the other system, the control and standby systems are determined and the
system switching disable cause is eliminated.
■Operation while the system is waiting for the start-up of the other system
Even though the RUN/STOP/RESET switch of a CPU module is set to RUN while the system is waiting for the start-up of the
other system, the CPU module is in the STOP state because the system has not yet been set to control system or standby
system. Thus, the CPU module does not execute programs.
The following table lists the refresh operations to be performed while the system is waiting for the start-up of the other system.
Type
I/O refresh
Network module link refresh
Intelligent function module refresh
■Timeout of waiting for the start-up of the other system
Measuring the length of the waiting time for the start-up of the other system is started upon completion of the initial
processing.
Set the waiting time for the start-up of the other system in "Other system Start-up Timeout Setting" of "CPU Parameter". (
Page 485 Redundant System Operation Setting)
When a timeout occurs, a stop error will occur. To prevent occurrence of a stop error, set "Other system Start-up Timeout
Setting" of "CPU Parameter" to "Not Set".
Precautions
• To start up the system that is waiting for the start-up of the other system as the control system, check that the other system
is not operating as the control system.
• When tracking communications are established by connecting the other system with a tracking cable or powering on or
resetting the CPU module in the other system, the CPU module that has been waiting for the start-up of the other system
enters the RUN state and executes programs. Thus, always check that program execution by the CPU module does not
cause any problems before powering on the other system or connecting the other system with a tracking cable.
• When the CPU module that has been waiting for the start-up of the other system becomes ready for tracking
communications and a stop error has occurred in the other system, a stop error occurs in that CPU module as well. In this
case, take a corrective action against the error of the other system, and turn off and on or reset the CPU module in both
systems.
• When the system waits for the start-up of the other system, tracking communication cannot be made because the other
system is off or either of tracking cables has problems. Check that the other system is on or tracking cables have no
problems. ( Page 799 When the L ERR LED turns on)
• Do not power off or reset the CPU module, or remove an SD memory card during an access to the SD memory card. (
Page 411 Using an SD memory card)
26 BASIC CONCEPT
412
26.7 Determination of Control System/Standby System
Operation
Only the input refresh is performed. The output refresh is not performed.
Data is transferred from the network module to the CPU module and from the
CPU module to the network module (SB/SW). Data is not transferred from the
CPU module to the network module (other than SB/SW).
Data is transferred between the intelligent function module and the CPU
module.