Emerson Exchange 365

Replace "MD" controller with MQ - Any Caveats?

So when I have some new MQ controllers in hand I want to swap them out for existing MD (not MD+) controllers. The MD controllers are doing fine; I'm just doing this gradually over the next few years in preparation for v14. 

Aside from the basic precautions e.g. upload controllers, backup database, etc. are there any concerns about this change? Is it indeed a "drop in" replacement?

• MD to MQ

John Rezabek

• 25 Aug 2017 7:18 PM
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4 Replies

• chessley

  

  • 25 Aug 2017 7:46 PM

  We just did the same thing for the same reason on about 10 controllers in redundant set-ups and had no issues, it was very painless. Aside from what you mention the the only observations I would pass on are that in Explorer the properties of the controller didn't change until the next time we did a download, also only change them out in pairs (don't leave a redundant pair running with one MQ and one MD) as there could be issues with a switch over from and MQ to an MD (I didn't test this personally it was advice given me when asking the some question to someone at our LBP).

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• Tinh Phan

  

  • 25 Aug 2017 7:58 PM

  In reply to chessley:

  That was a very good advice by the LBP giving that there are some codes that is supported in the MQ controller that is not supported in the MD which could cause the switchover to fail or there will be a bump in our process.  Here is the DeltaV Controller Redundancy info:

  http://www.emerson.com/documents/automation/57664.pdf

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• John Rezabek

  

  • 25 Aug 2017 8:54 PM

  In reply to Tinh Phan:

  So I would do this with the process down? . . . wouldn't the procedure be

  1) Swap out "standby" MD controller for new MQ

  2) Once transfer of configuration is complete, status will show "partner available"

  3) Force redundancy switchover

  4) Replace the (former) primary MD controller

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• chessley

  

  • 25 Aug 2017 8:58 PM

  In reply to John Rezabek:

  We did it with the process running but you know your plant best as to how switchover effects your operation, but the procedure you give is what we did. There is no issue with a switchover from and MD to and MQ and just the other way around so you can do it without taking the controllers down.

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