Run case once if value > X then "only" reset when value < X

[Newbie999]

Hi, 

I have a case structure and its "true" section is triggered by a comparison of a value against a constant, so if value > constant it runs the case, the case calls a subVi (gmailv86) but it sends loads of emails because the condition is met lots of times before dropping below the constant. how can I make the case only send "one email" then wait until the value drops below the constant value?

Hope this makes sense and sorry for being a newbie!

Steve

[GerdW]

Hi Steve,

what about a rising edge detection used on your case condition?

Well, there's a ready-to-use function for that purpose in the Pt-by-Pt-dunctions palette...

[tst]

Other than the built in edge detector, you can also find some others online, such as in the OpenG VIs, but it also helps to understand the basic concept behind them:

In this example, the bottom node is a feedback node, which outputs the value that was fed to it the previous time it was called. This allows you to compare the current value of the boolean to the previous one.