What is the limitation by using peer to peer connection through the BMENUA0100 used in HSBY architecture?

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For an Hot-Standby system, there is a limitation for an application that have READ_VAR and/or WRITE_VAR to communicate over network with another remote PLC through BMENUA0100 modules.

BMENUA0100 Firmware version 1.10.25 and 1.01.50
Control Expert v14.1 and above

The definition of the gateway inside the CPU IP address screen in Control Expert will be linked to only one IP address backplane of BMENUA0100. For example, it could be the IP address backplane of the BMENUA0100 in A rack.
After a switchover to standby PLC in B rack, communication is always routed through the main BMENUA in A rack. So, it is not possible to power off A rack when running on standby PLC, otherwise remote PLC communication will be lost. In this case, it is recommended to not have sensitive data exchange with remote PLC.

Timeout value for READ_VAR and/or WRITE_VAR must not be 0. We suggest setting the timeout of 500ms for BMENUA0100 (this value must be tuned) and in any case, not = 0.

GEST word of READ_VAR and/or WRITE_VAR must not be exchanged with standby PLC.