PID instrumentation and application

[GerdW]

Hi Milon,

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@Chowdhury_Milon wrote:

As I said before, after getting the process value (PV) steady state (after 190 s in the picture), I want to stop this code and go to the supply step. How can I go to the supply step by stopping this nutrient solution preparation code?

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What about changing that stop condition?

Maybe something like "stop when PV is in valid range for x seconds" - instead of "stop if PV is in valid range"?

[Chowdhury_Milon]

Mr. GerdW

Yes, I agree with you but the PV setting time is not always the same. I can understand the condition but can't set the proper vi. I tried to use "In Range and Coerce" vi but it is not the proper one. Would you please give some suggestions or show some similar examples?

[GerdW]

Hi milon,

you need to combine InRange with ElapsedTime to get your "pv is in range for a certain time"...

[Chowdhury_Milon]

Hello Mr. GerdW, 

Greetings. I am really sorry, I tried to combine the "In Range and Coerce" with "ElapsedTime" but can't succeed. if you have any idea, would you please share that with me? 

Thanks in advance. 

[GerdW]

Hi Milon,

as usual:

What have you tried? Where did you fail?

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@Chowdhury_Milon wrote:

if you have any idea, would you please share that with me?  

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As said before: the idea is to check for "is in range for a certain amount of time"…