ControlLogix Redundancy with Ethernet/IP

[a.yearsley 0]

We're just looking at setting up a redundant ControlLogix chassis pair. The pair communicate to a single I/O rack via Ethernet/IP, and we will also have a SCADA system talking to the redundant chassis. All the examples I've seen for redundant pair show 2x EN2T cards in the controller chassis. One card for the connection to the I/O rack. A separate card for connection to the SCADA/HMI. Is this really necessary? or just 'best practice'? I would've thought you could have just one EN2T card in each controller chassis. Then connect everything (SCADA, I/O rack, controller chassis) to a managed switch sitting in the middle. SCADA and I/O comms can be separated via VLAN. Would this work, or have I missed something? Edited 3 Feb 2014 by a.yearsley

[Michael Lloyd 85]

I never poll with SCADA and use the same card for remote IO. I tried it a long time ago and the PLC kept faulting on remote IO rack comm fail. Ethernet isn't deterministic. It's "spray and pray" (sort of) Apparently the Broncos are trying to do that for their Superbowl comms too... Edited 3 Feb 2014 by Michael Lloyd

[Shawn Tierney 2]

Today, many still separate I/O and SCADA networks. However, with a good managed switch it's not necessary, as many using the new 5370 CompactLogix controllers know (they are limited to a single Ethernet port.) I do highly recommend A-B's free Ethernet Capacity Tool to help you determine your network load, as well as these two Redundancy docs which list actual requirements and are very helpful: http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um535_-en-p.pdf http://literature.rockwellautomation.com/idc/groups/literature/documents/rn/1756-rn694_-en-p.pdf Hope this helps!

[andreik 0]

Hi,

Good day to all,

 

I got a follow up question regarding the redundancy configuration. Please refer to the image attached (Page 26, Enhanced Redundancy User Manual). Notice the 1756 ControlLogix I/O inside the green box! Does anyone know how to add and configure this chassis to the I/O configuration tree of RSLogix5K (Logix Designer 5k)? On my configuration, I've also inserted 2 MVI56E-MNETC Modbus TCP/IP Module in addition to the standard I/O Modules. Is my configuration possible? I appreciate any help I could get. Thank you very much.

 

Sincerely,

Andrei O. Karunungan

[Shiner 2]

On the MNETC's: Because those modules are manufactured by Pro-Soft, I do not believe AB's redundancy will support them.  They would need to be in a remote rack.  If you put any unsupported module in the redundant racks, they will not synchronize.

 

Adding remote racks:  In your redundant rack in the project tree, on the Ethernet card you are communicating to the remote IO with right click and add modules.  You must first add the EN2T for the remote chassis and specify the chassis size, then you can add the other cards.  Depending on your revision, if you are online, you can select scan for modules to have the software auto-detect them.  This will help make sure you match your major and minor revision of the added equipment.

Edited 18 Apr 2016 by Shiner