Emerson Exchange 365

Looking for a way to use module errors to switch the position of a valve.

Hello All,

    I need some feedback on a way to use module errors to change the position of a valve. What I am trying to accomplish is, if a specific valve has an error, loses a limit switch or power, a different valve will open. I would like to build this in a control module ACT block using module level parameters in the logic, but I am unsure of what specific parameters to use to cover all failure possibilities. A little insight would be helpful. Thanks.

Lucky

• 24 Mar 2015 2:54 PM
• Cancel

1 Reply

• Youssef.El-Bahtimy

  

  • 25 Mar 2015 3:58 AM

  Is the valve you are trying to open a Fail Open valve? If so, then the valve's interlocking conditions should be used to drive the valve to fail safe open detection of an integrity error on the first valve, but only if the condition has persisted for more than a momentary period (otherwise you risk falsely tripping the second valve for spurious events). The CND block implemented as interlock condition has a TIME_DURATION parameter to set the length of time for which the condition must be true for it to act.
  
  If you are energizing the second valve (fail closed valve), I would actually be hesitant to have this valve open automatically unless you have a pretty thoroughly implemented supervisory control strategy in place. Should the operator override this actuation? Should it occur regardless of valve mode or process operating condition? Will the operator be alerted to the fact that this happened?
  
  What does the first valve control, and what does the second valve control?

  • Cancel