Answer: For M580 model reference ends with xx40, Control ports 2 and 3 are designed to connect the RIO network to the CRA drop modules. These ports are not dedicated to interconnecting several M580 PLCs.
If the multiple set of M580 systems is directly connected in the upstream network using the control ports of the CPU, it might cause some LLC storm in the network, and it is not a valid architecture and not recommended by Schneider Electric.

For the upstream connectivity, the recommended architectures are :

• Either to use another Ethernet communication module such as BMENOC03xx and provide the isolation between the RIO and upstream connectivity network. With this architecture, you may also take benefits of RSTP architecture with redundant cables for connectivity with the switches.

• Or to use the CPU Service port (no redundant cable possible because RSTP is not available) (*) :

(*) Be careful,  in case some eRIO drops or other ethernet modules are configured and attached to each system, other preconizations are necessary (not the topic of this FAQ) because both systems behave to the same subnet network.
 

Released for:Schneider Electric USA