ControlLogix Redundant IO Racks

Is this possible?

I can find literature on redundancy but this covers only the CPU racks and redundant ControlNet to single racks.

I can't see anything that indicates it is possible to have redundant IO Racks.

Anyone ever seen or done this?

I haven't seen it done no, but didn't AB release the 1715 series I/O for this?

Before RA bought ICS Triplex and got access to their AADvance I/O platform, there were some specific dual-rack, dual-module wiring and testing and diagnostic methods you could use to get redundant I/O for SIL2 systems.

The current state of the art is the AADvance I/O platform, which is sold for ControlLogix as the Bulletin 1715 I/O system.

My only personal experience with this was somewhere below both of those; we wired up two parallel I/O chassis (connected over ControlNet to ControlLogix Redundancy) assemblies and brought our inputs to both "racks", then monitored all the communications paths and module diagnostics to decide which input to use in the control logic. It wasn't the official self-testing SIL2 stuff but it sufficed for the fault tolerance I needed on that system.

Thanks for the info.

Our client currently has a ControlLogix system with IO remote IO racks connected with ControlNet. We're changing the single processor with a redundant pair and going to utilize both ports A and B (currently only A is used) on the ControlNet cards.

As a side they have asked if one of the racks can be made fault tolerant.

I've found some SIL2 literature

http://literature.rockwellautomation.com/idc/groups/literature/documents/at/1756-at012_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm001_-en-p.pdf

I'm presuming this is the direction I should be looking.

For your application and circumstances, the "RA style SIL2" manuals are definitely the way to go.

There is also a 1756-AT010 document you can have a look at, which focuses on high-integrity I/O using Subroutines instead of AOIs.

It's been five years since I reviewed any of that stuff, so see if you can get an RA consultant to discuss it, to make sure you're looking at the current revisions or releases.