Functions Restricted In A Redundant System - Mitsubishi Electric MELSEC iQ-R Series User Manual

Functions restricted in a redundant system

The following table lists the functions restricted when using the remote head module in a redundant system.
Function
Remote operation Remote RESET
RAS function Event history
function
Monitor function Device/buffer
memory batch
monitor
Synchronization CC-Link IE Field
function Network
synchronous
communication
function
Inter-module
synchronization
function
SLMP communication function
MC protocol communications function
Restrictions
Only when this operation is performed on the remote head module of the control system, the entire system is
reset. However, depending on the status of the remote head module, remote RESET may not be performed.
■When there is an error in remote head No.1 or remote head No.2
• When only remote head No.2 is mounted: The system is not reset.
• When a major error occurs in remote head No.1 or remote head No.2, the system on both of remote head No.1
and remote head No.2 is not reset.
(When only remote head No.1 is mounted, the system is reset.)
■When the remote head modules of both systems are not in the STOP state
When the remote head module of the control system is in the STOP state and the remote head module of the
standby system is in the RUN state, the remote head module of the control system and the standby system cannot
be reset by performing the remote RESET operation on the remote head module of the control system. Perform
the remote RESET operation after setting the remote head modules of both systems to the STOP state.
■When a remote operation is performed on the remote head modules of both systems via different routes
When a remote operation is performed on the remote head module of the control system and the standby system
via different routes, the remote head module of the control system and the standby system cannot be reset by
performing the remote RESET operation on the remote head module of the control system. To perform a remote
RESET operation on the remote head module of the control system, cancel the remote operation on the remote
head module of the standby system before performing the remote RESET operation.
Events related to system switching are stored in the remote head modules of both systems, but events that have
occurred in one of the remote head modules are stored only in that remote head module. Also, events that have
occurred in a module on the base unit are stored only in the remote head module of the control system.
Only the events stored in individual remote head modules can be cleared/displayed.
The execution result of the current value change executed in the control system for the devices of remote head
module is not reflected in the new control system even if systems are switched.
Connect the engineering tool to the new control system and re-execute the current value change.
Cannot be used.
• When systems are switched during communication, since neither the remote head module of the control system
prior to system switching nor that of the new control system can send a response and a response wait timeout
occurs, a retry from the communication equipment is required. However, for the RJ71C24, depending on the
response monitoring time setting, a response wait timeout may not occur.
• In SLMP (MC protocol) communications using the remote head module, when performing communications to
the other system in a state where the other system cannot respond (such as reset and disconnection of Ethernet
cables), a timeout error may occur.
1 FUNCTIONS
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1.8 Redundant Function
1