Redundant Contrologix w/ dual Modbus ports

[flandes]

Hi,
I have a redundant CPU ControLogix with single 13 slot i/o rack and PanelView on controlnet. Redundant supplies, etc. but pretty much works out of the box.

Problem: I need dual Modbus RTU comms out of this system. Customer wants 'redundant' Modbus to his DCS.

My original attempt was Prosoft MVI Modbus cards, one in each CPU rack. A-B tech support says don't do it. Prosoft says it's ok, depending on who there you ask. Being a redundant system, this makes me a bit nervous to try! Does anyone have any comments on this configuration?

Next thought is put Prosoft cards in I/O rack. Appears this is no good as I get a ControlNet memory size error when configuring the rack. Something to do with memory usage of all the cards in the I/O rack + the Prosoft card exceeds the CNB node requirments for the rack.

I suppose my final solution is to loose the Prosoft cards and use a DIN rail Modbus gateway with EthernetIP or the like. A bit messy and expensive as I already have the Prosoft cards.

Any comments are appreciated!
Thanks

 

[Wfacac]

What I've done is have the controllogix in independent racks with the SRMs and a controlnet card, and running your I/O in a separate rack as RIO. Then I put a single Prosoft in the I/O rack and run single line Modbus from there. The redundant processors keep the I/O alive and your modbus line is never in jeopardy.

 

[BrooksWinchester]

If using a PC is a possiblity I have a different kind of answer for you.