AB Hardware question: Redundancy & Control Net !?

Hello everyone,

I have lot of question here:
I am new to a factory which use AB ControlLogix 5575 & RSLogix 5000
I open their control panel and I saw their main control Panel has:
1st Rack has Logix 5575 + Redundancy module + Ethernet/IP + ControlNet
2nd Rack has Logix 5575 + Redundancy module + Ethernet/IP + ControlNet
(basicly the same for both rack, and they both DO NOT have any I/O module)
other 2 control panel at different places has multiple AI AO DI DO BUT DO NOT have main processor like 5575, they only has 1 modul of Ethernet/IP and dont have Control Net !?

So what the different and what their purpose are for Redundancy, control net ?

Thanks

Which network is your PC connected to? Is it connected to both? Maybe someone upgraded and just never eliminated the old setup?

(Basically the same for both rack, and they both DO NOT have any I/O module)

Click to expand...

That's how ControlLogix Redundancy works. The controller chassis only have CPUs, network modules, and Redundancy Modules.

It's possible that the ControlNet network modules were part of an older configuration and were not removed, or that they are connected to a network that you didn't examine. Follow the cables, browse the network with RSLinx, or examine the user program in the ControlLogix to see what role the ControlNet modules play.

ControlLogix Redundancy, especially in the modern revisions, can use either EtherNet/IP or ControlNet for its IO networking.

Revisions from more than about five years ago only supported ControlNet for Redundancy systems because it was the only way to get the necessary media fault tolerance until the advent of more reliable industrial switches and fast ring network technologies like Device-Level Ring (DLR).

If it's important we can look up precisely when EtherNet/IP was introduced to Logix redundancy.... it's not my job to have those details memorized anymore.