Mitsubishi Electric MELSEC iQ-R Series User Manual page 126

When communication is unstable
The following lists the actions to be taken when link scan time or transmission delay time is long or when a transient
transmission timeout occurred.
Check item
Is the ambient temperature for the module within the specified range?
If the above action does not solve the problem, perform the self-diagnostics test to check for hardware failure. (Page 95
Self-diagnostics test)
When redundant system function is used
■An error occurs in a CPU module
When a redundant system is configured, if an error occurs in a CPU module, check the following items.
Check item
Is pairing setting made when the redundant function module is used?
■System switching cannot be performed
When system switching cannot be performed by a system switching cause of the RJ71LP21-25, check the following.
Check item
Is the power supply module, CPU module, or redundant function module of
the standby system operating normally?
Is the cable disconnected in the standby system network module?
■Cyclic data communications are disconnected or are unstable
If cyclic data communications are disconnected or are unstable when the RJ71LP21-25 system switching occurs, check the
following items.
Check item
Is the station number of the network module set to "No. n" and "No. n+1" for
system A and system B in the redundant system?
Is the cyclic data communication range included in the tracking target?
( MELSEC iQ-R CPU Module User's Manual (Application))
4 TROUBLESHOOTING
124
4.4 Troubleshooting by Symptom
Action
Keep the ambient temperature within the specified range by taking action such
as removing heat source.
Action
Set pairing in "Network Range Assignment" of "Required Settings". (Page
55 Network Range Assignment)
Action
Perform troubleshooting on the power supply module, CPU module, or
redundant function module of the standby system.
 MELSEC iQ-R CPU Module User's Manual (Application)
Check the wiring condition and put the network of the standby system in
normal condition.
Action
Correct the setting so that the station number of the network module is set to
"No. n" and "No. n+1" for system A and system B in the redundant system.
Correct the tracking setting.