Using more than one Controlnet card to access data

[AshWW]

Hello!

I am working on a Controllogix project with redundant PLCs. The primary and secondary racks both contain:
[0]L71
[1]EN2T
[2]CN2R
[3]CN2R
[4]RM2

Each of the two CN2R modules are accessing different remote CN2R modules connected to Remote IO. Say slot [2] is connected to side 1, and slot [3] is connected to side 2. Both CN2R modules are on the same network. The way it is set up right now is if slot [3] gets disconnected in Chassis A, the system will switch to Chassis B. If slot [3] also gets disconnected in Chassis B then I lose connection to all IO on side 2. Is there a way to maintain this connection through slot [2]?

Thanks in advance!

 

[daba]

I think if Chassis A, Slot{3} connection failed, AND Chassis B, Slot[3] failed, both of them using redundant media, then you've had four failures....

I would be looking elsewhere for a solution, rather than trying to hold onto a connection that has already failed four times.

But a simple answer is :- yes you might be able to schedule all your I/O in both CN2Rs, and programmatically inhibit the connections served by the other module. But if that were plausible, why were 2 CN2Rs used in each chassis in the first place ?