ControlLogix Redundancy Ethernet/IP IO Configuration

[Geospark]

I just want to add some more information with regard to tested/verified and recommended network topology designs which may be implemented for a Rockwell High Availability System (ControlLogix Redundancy) using Ethernet I/O...

ID: QA13697 | Access Levels: Everyone
ControlLogix Redundancy High Availability Ethernet System Testing

Please refer to the presentation (pptx) file at the end of the technote which was just released February 2020.

Note: While these DLR/PRP topologies are tested and recommended for implementation, other configurations may work, but there is a higher chance of failure during normal operation and Redundancy related events.

These design implementations are guideline recommendations only, and while I would assertively advise users to follow them, there are no stipulations as such which dictate that we must implement them. Rockwell will Support you where you have implemented a non DLR/PRP Redundancy topology, where the expected hardware or configuration functionality is not working correctly. All while under the advisement, of course, to move to a tested and verified design.

Regards,
George

 

[Contr_Conn]

Rockwell will Support you where you have implemented a non DLR/PRP Redundancy topology

This is questionable statement when it comes to ControlLogix Redundancy as far as I know.

 

[Geospark]

Forethought: I don't make off the cuff statements...

...Rockwell will Support you where you have implemented a non DLR/PRP Redundancy topology...

This is (a) questionable statement when it comes to ControlLogix Redundancy as far as I know.

I made the statement you refer to in response to this post...

Illegal? or not recommended/supported? One suggests jail time, the other just a voided warranty/no tech support help.

To break my statement down a little more, for you...

I am referring to the fact that Rockwell will assist you if a piece of hardware or software, within a "Redundant Topology" (whether implemented as recommended, or not), is not performing as expected, as sold and intended for use. As for the "overall" implementation, at the Redundancy level; they would, of course, also advise that the design be reconsidered, if needs be, and as I was careful to add at the end...

...All while under the advisement, of course, to move to a tested and verified design...

Aside from what I may claim to know Rockwell will or will not do in such cases, I will refer you once more (if you did not look at it?) to the presentation linked in the technote I added. I'll actually link it here this time...

ControlLogix Redundancy: Recommended Network Topologies and Design Guidance

The title of that document, alone, clearly states that the enclosed network topologies are recommended (not compulsory) and are presented as a design guidance (not restricted to just these). It also states further in (and as I added to my post)...

"...While other configurations may work, there is a higher chance of failure during normal operation and redundancy related events...".

This is Rockwell acknowledging that other configurations may be used, while advising of the possible higher risks of failure in doing so.

Nowhere in this quite up-to-date presentation do Rockwell categorically stipulate that we must use one of these topologies for a ControlLogix Redundancy System, else the gavel may fall.

While I am pointing the above out, I will reiterate that I would always assertively advise the use of Rockwell's tried and tested methods. It's just that we should not be saying do it this way, and this way only, or else...

If another "entity" is stipulating that ControlLogix Redundancy must be implemented in a very specific manner, such as to the recommendations of the manufacturer, then that is another matter. But the manufacturer themselves, in this case, are not stipulating anything. They are simply recommending to us that we use the designs which they have proven and tested to be the most effective in achieving efficient Redundancy.

Regards,
George