1756-l72 controllogix redundancy

[Rahul3005]

Hey Members,

I hope all of you are doing well , I am using a 1756-l72 redundancy system, communicating RIO on DLR network.

When both my PLC are powered on , my system works flawlessly when I initiate a switchover from RM2 module , everything works ok.

When I turnoff my primary rack , my SYNC will become Primary , which is once again working as expected.
The issue is when the primary rack is powered off , I get IO's not responding.
I have set 1756-EN2TR on both redundant chassis as "RING SUPERVISOR".

Is this normal for a DLR network , or am i missing something ?

 

[Rahul3005]

architecture

please see attached architecture

 

[Ken Roach]

Thank you for posting the system architecture and those details about the configuration !

The most likely issue is the DLR Supervisor configuration.

Rockwell Automation Application Technique document ENET-AT007 describes the recommended configuration of 1756-EN2T modules in a Redundancy system with DLR.

The Supervisor Precedence value determines which device will be the Active Supervisor. You should configure at least one Supervisor-capable node outside of the redundant CPU chassis pair.

You may also configure Supervisor-capable nodes (with lower Precedence values) in addition, if you wish.