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Configuring valve to close automatically after time elapsed - Enabling Force Setpoint in Auto

I'm attempting to configure a normally closed valve to revert closed 15s after being given an open command.  This will be the normal transition every time; Valve commanded open, 15s later needs to revert to closed.

I'm in DeltaV 12.3.1 and the valve module class is S_V11_IP_120

My thinking was to use force setpoints. 

Where is the function for enabling "force setpoint in auto"?  How do I enable it. Also will I need to suppress the "process action in auto" alarm once it's enabled (since the action is considered normal)?

Larger question - Is there a better way to do this?

SimHogan

• 9 Jan 2019 7:05 PM
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3 Replies

• Matt Stoner

  

  • 9 Jan 2019 7:24 PM

  There is a parameter on the DC_CTRL block called FS_IN_AUTO, set this True and all the force setpoints will work in AUTO and CAS.
  
  Just disable the Alarm on instance (hopefully configurable if class based), it is isn't then you can change the class to make this as configurable.
  
  Not knowing the normal transition time of the valve and if you have limit switches or not, there is an option on DC1/DEVICE_OPTS that would allow this to occur (Passive when confirmed) that you could possibly use if the normal transition time is around 15 secs for the PV to be reached.

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• SimHogan

  

  • 9 Jan 2019 9:01 PM

  In reply to Matt Stoner:

  Thanks Matt. I found FS_IN_AUTO, and set to true. I will be testing asap.
  
  Regarding the second option, the valve is fail closed, and only has a closed limit switch. There is no confirm after command to open, only that the zsc is unmade - so I'm not clear if 'Passive when confirmed' is an option. It's a small valve, I would expect it opens within 5 secs.

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• Matt Stoner

  

  • 9 Jan 2019 9:24 PM

  In reply to SimHogan:

  Yeah that is what I was thinking you probably had so the FS is best.

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