Time delay while loop before stopping the loop

[havevun]

Hi All,

I modified this code from one of the example in the forum. I forgot which thread. Original file name is "loop speed control.vi"

I want to measure pressure and compare with target pressure. Once the pressure reading is higher than the target pressure, I hold the output high for 5 seconds and turn it to low. 

When It goes back to low, I want the to exit the loop or when I pressed the stop button. I do not how to do this one. Please help.

Thanks

[Gregory]

Hi Havevun,

Try using a case structure with a couple different states. For instance "Measure", "Hold" and "Exit". This way you are only checking for one condition in each state.

[crossrulz]

Yeah, you definately want a state machine.  This probably would become very simple when you break down the states properly.

[havevun]

Hi Gregoryj and Crossruiz,

Thank you it really helps. The logic is cleaner than my previous. 

There is this thing that I need to fix.

Motor is used to increase pressure

Valve is to dump the pressure. 

I used delay to hold thre pressure once it reach the target pressure. (TRUE condition). 

Pressure readings fluctuate.

The problem that I have here is that once the pressure reading is higher than the target. I do not want the code to return back to "False" (pressure reading is lower than target). 

Please advise.

[Gregory · Accepted solution]

I can't view your VI (I'm using LV 2014). Please see my attachment for an example. See what happens when you make the value of numeric >= 1. Turn on the highlight execution if it does not make sense.

[havevun]

Thank you, Gregoryj. 

It works like a charm

[Gregory]

You're welcome. As a side note, it is best practice to type define the enum, so that if you change it, it will update everywhere. I didn't do that here to limit the file dependencies.