Emerson Exchange 365

PID BEHAVIOR

Hello everybody ;

I want to know how I can reverse the output of PID block example when I give from the faceplate 25% I want the output to be 75%.

Thank-you for your prompt response.

Best regards.

Butler faith.

Butler faith

• 14 Aug 2015 11:34 AM
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8 Replies

• Adam Bagosi

  

  • 14 Aug 2015 11:40 AM

  Hi
  check PID/IO_OPTS/Increase to Close

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• James Beall

  

  • 14 Aug 2015 11:46 AM

  In reply to Adam Bagosi:

  Hello,
  Or, if you are using and AO block with your PID block, check the same option in the AO block and NOT in the PID block.
  Good luck!
  James

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• rasa

  

  • 13 Sep 2016 5:40 PM

  In reply to James Beall:

  hello,
  
  when we use increase to close in AO Block ,,in faceplate of pid the output will be out put of pid that is not same with AO's out
  for example if pid's out =25% so valve 's out should be 75% .... but out in faceplate shows 25%
  
  what shoud we do??
  
  BR,
  F.R

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• Matt Stoner

  

  • 13 Sep 2016 6:22 PM

  In reply to rasa:

  The 75% on the AO/OUT is the value that is being sent to the field but the actual physical valve will still be 25% open (unless it isn't an increase to close valve) so you shouldn't do anything as the FP is displaying correctly for what the valve position should be in the field.
  
  Regards

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• rasa

  

  • 14 Sep 2016 9:10 AM

  In reply to Matt Stoner:

  thank you so much matt,
  
  but whats the difference btw pid/io op and ao/io op (increase to clease)?
  
  BR,

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• rasa

  

  • 14 Sep 2016 9:12 AM

  In reply to Matt Stoner:

  so dynamo object of valve and the faceplate indicates true value ( out of pid)?

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• Matt Stoner

  

  • 14 Sep 2016 1:19 PM

  In reply to rasa:

  There is no difference between the two options but it only works when the I/O is being driven from that block.
  If you had IO assigned to the PID block then it would work the same as the AO.
  If no I/O is assigned to the PID block then the option does nothing.

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• Matt Stoner

  

  • 14 Sep 2016 1:31 PM

  In reply to rasa:

  I don't know what dynamo you are using but the faceplate will only be showing the OUT of PID typically.
  
  The valve dynamo could be looking at the PID but typically it should be pointed at the AO/PV (because OUT is the signal to the field and not valve position). If the AO has the IO_READBACK configured with a DST then the PV is the actual valve position and if it has no DST then it is the Implied Valve Position (where it should be).

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