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AO block without AUTO option

I would like to setup AO control module without AUTO option. So the AO control module will have only MAN and CAS selection. Is there any issue when it goes from CAS to MAN? This helps us to simply operator training. 

kravindranath

• 5 Jan 2021 2:09 PM
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2 Replies

• Matt Stoner

  

  • 5 Jan 2021 2:43 PM

  Recommend you just use AUTO and CAS because if the AO is a Fail Open (Increase to Close) the output value of 0 in Manual will actually be 100% open in the field and be really confusing to an operator and most likely cause an incident. If you use AUTO instead then 0 SP will always be closed regardless of Increase to Open or Close.
  
  Should be an issue changing modes as long as all the statuses are handled and passed properly.

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• John Rezabek

  

  • 6 Jan 2021 1:27 PM

  Just curious, is this AO for a conventional 4-20 mA output or fieldbus? The old DVC5000 would allow only OOS and CAS enabled (the way we configured AO's by default, before class based modules) and all other modes disabled. As we started upgrading DVC5000's to 6000's, we found we had to leave all modes enabled.
  A second question: Is it conceivable to simply not expose AO blocks' mode for operator manipulation?

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