elfrider

ControlNet reschedule after new module?

6 posts in this topic

Hi all,

Looking for some confirmation on something please. I'm looking to add a new module (1756-EN2T) to the Local (not remote) rack of a ControlLogix system (L73 @ firmware V33) which has ControlNet to two remote racks. Am I correct in saying I can do this while keeping the processor in Run, i.e without the need to reschedule the ControlNet network, and therefore switching the CPU to Program? I realise my ControlNet file will be out of date until such time as I schedule but I'm really not in a position to be able to take this process offline at the moment.

Thanks.

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The -EN2T is an Ethernet module and would be completely independent of the ControlNet system. ControlLogix (1756-*) supports "RIUP", Removal and Insertion Under Power, so you can pop the -EN2T into the chassis and add it to the IO configuration without stopping the PLC.

What are you planning to do with the module? If it's just for PC, SCADA, or HMI access, it doesn't need to be in the IO tree at all.

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Thanks Joe,

I'm adding it for messaging purposes to some sub-networked PLC's. I was planning to add the card (& sub PLC's) to the I/O tree which I'm sure I can do whilst online anyway. 

My main concern was that the comms to the ControlNet racks would fall over for some silly reason but thanks for confirming that's not the case.

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It's been a few years since I did much with ControlLogix (we're mostly CompactLogix and SLC500 here) and I don't have a test rig to confirm, but I'm 99% sure you can plug in the -EN2T, add it to the IO tree, and set up MSG instructions without disrupting operations.

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The only bug I've run into was when I tried to remove an 1756-ENBT and insert a 1756-EN2T at the same location and with the same IP Address.

Been a few moons since I did that, but what you describe should be clean and relatively safe.

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1 hour ago, BobLfoot said:

remove an 1756-ENBT and insert a 1756-EN2T at the same location

Hmmm.  I would expect that to work, unless the I/O tree keying was set to "Exact Match".  I currently have an ENBT in my lab where an old processor thinks there's an ENET, and it is scanning I/O through it properly.  I would expect an EN2T to do the same.

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