ControlLogix Enhanced Redundancy System

Hi all.

i'm implementing a contrologix redundant system, each chassis of the redundant pair have two 1756-EN2TR for a DLR network.

The redundancy applies to controllers and remote I/O chassis. I have two procesor racks and two remote I/O racks.

Rockwell Automation recommend the use two 1756-EN2TR modules per procesor chassis.

My doubt is about the configuration of the I/O tree in RsLogix 5000, the remote I/O racks should be associated to both 1756-EN2TR installed in the controller chassis?

i doubt this, because the SIL2 Add-on instructions takes the data of only one module, then how must be configurated this two 1756-EN2TR to work together and proces the same information and send this data to the controller?

I appreciate any advice and recomendation about this.

The obvious answer is "ask the person who recommended two modules per chassis".

The two most important manuals for ControlLogix Redundancy are the Enhanced Redundancy User Manual (Publication 1756-UM535) and the Release Notes for each Redundancy firmware.

Each of these documents is in the top 5 results when you use the keyword "redundancy" in the RA Literature Library.

Similarly, the keyword "SIL2" returns the important documents for the use of ControlLogix in SIL2 safety-related applications.

My guess is that the Rockwell person you spoke with recommended separate Ethernet networks for HMI and for I/O purposes.

Ken Roach said:

The obvious answer is "ask the person who recommended two modules per chassis".

The two most important manuals for ControlLogix Redundancy are the Enhanced Redundancy User Manual (Publication 1756-UM535) and the Release Notes for each Redundancy firmware.

Each of these documents is in the top 5 results when you use the keyword "redundancy" in the RA Literature Library.

Similarly, the keyword "SIL2" returns the important documents for the use of ControlLogix in SIL2 safety-related applications.

My guess is that the Rockwell person you spoke with recommended separate Ethernet networks for HMI and for I/O purposes.

Click to expand...

hi thanks for your comments.

I found new information about this. A posible solution for this configuration problem is configure one of the 1756-EN2TR modules in Listen-Only mode and the second module as Rack Optimized. Unfortunately i could not find an example of program or an aplication note who describes this procedure.

I think the procedure is.....

1.- In one 1756-EN2TR add the ethernet comm module and I/O modules that form the remote Rack. Specifying the IP adress of the com module.

2.- In the second 1756-EN2TR add the ethernet comm module whit the same IP adress than in the first module and change the comm format to Listen Only. Add the I/O modules specifying on each module the comm format as Lysten Only.

This procedure is as i think who should be.

I apreciate advices and corection.

Thanks.

Where did you get this "new information" ?

ControlLogix Redundancy handles media robustness by using either dual media (ControlNet) or by using a high-availability Ethernet method like Hiper-Ring or Device-Level Ring.

Listen-Only connections are not a method for providing an alternate network module path to an I/O module. That is just not how ControlLogix Redundancy works.

On page 42 of the ControlLogix Enhanced Redundancy User Manual there is a diagram that includes two Ethernet modules in each chassis. It shows one set used for HMI connectivity and one set used for I/O connectivity.

This is the architecture that I guessed your RA representative was trying to describe to you. This is the way I would build the system. This is the way the system architecture is described in the User Manual.

Hi

This information was recommended by a Rockwell ingeniere.

In the Safety Reference Manual "Using ControlLogix in SIL 2 Applications" ( http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm001_-en-p.pdf ) on the 19 page are illustrated the topology DLR that i am configuring.

I am agree with you, two 1756-EN2TR modules seem to be unnecesary.

Thanks for all your coments.

Thank you for posting that specific manual and page.

That diagram does show two Ethernet modules per Redundancy chassis, and the reason for this is described on page 29:

Use two 1756-EN2TR EtherNet/IP modules for SIL 2 safety loops.
Each redundant input must be routed through separate EtherNet/IP communication modules.
The SIL 2 output and its secondary shutoff must be routed through the separate 1756-EN2TR EtherNet/IP modules

Click to expand...

Two 1756-EN2TR modules are used because in that particular style of system (Fault Tolerant SIL2) the "redundant inputs" need to be connected to the controller using separate paths, not because one of the paths needs to be a backup to the other. Listen-Only connections have no role in this, and Controller Redundancy is less important than the fact that there are two Input modules with separate logical connections to the controller.

I still recommend that you get advice from the "Rockwell Engineer" who recommended the system architecture. Safety Shutdown systems should not be guessed at.