Mitsubishi Electric MELSEC iQ-R Series User Manual page 179

When a cable error occurs on the inactive side between the extension base units
When the extension cable is redundant and an error occurs in the extension cable on the inactive side between redundant
extension base units, a continuation error occurs in the CPU module of the control system. Unlike having an extension cable
error on the active side, system switching or switching of the communication route does not occur.
How to check the extension cable faulty area
When an error occurs in the extension cable, the extension cable information can be checked in the detailed information for
the error code.
Precautions
• If no communication can be performed with the extension base unit on the previous level or with the main base unit due to
an extension cable error or the input power supply of the power module mounted on the extension base unit turning off, the
output of that module on the extension base unit and the extension base unit in the level immediately below will be cleared
regardless of the setting. Therefore, configure the system so that clearing the output of the module on the extension base
unit does not cause a problem.
• If the standby system cannot be switched due to a stop error, even if a stop error occurs in the control system due to an
extension cable error on the active side, system switching and switching of the communication route are not performed,
and control cannot continue. Therefore, if a cause of the system switching failure occurs, eliminate the cause immediately.
11 BASIC CONCEPT OF REDUNDANT SYSTEM
11.8 Access in a Redundant System with Redundant Extension Base Unit
11
177