So you have a ring configuration that isn't setup to act as a ring.
You could have a redundant network without using a ring. You basically just make two separate cable runs from A to B to C. Two cable from A to B and two cables from B to C. Or one goes A, B, C and the other goes A,C, B. Your data is always sent on both cables in case of a failure.
But what you do not do in that instance is what Contr_Conn mentions and "improve" the network by connecting C back to A and creating a ring. That said, with a limited amount of data, this could still function. A PLC and two remote chassis would be a limited amount. Throw an HMI in there and everything goes to pot. Anything that broadcasts would bring the network to its knees.
You have your cable in a ring configuration and you have equipment capable of using the ring. You just need to enable it at this point. Select at least one device as the ring supervisor. You can select two, or even all three. that would provide a backup if the supervisor failed.
Once you have a supervisor you should also be able to connect with the DLR tool.
OG