Boolean cant be switched to off

[leololo]

Hello,
I want to do a continuous loop, that changes the value of valves over and over again. I want to be able to stop this loop by pressing the boolean again and switch it to off. But once my loop is running, the boolean cant be pressed anymore. 
Could you maybe help me?
Thanks so much in advance!

[Bob_Schor]

I'm guessing that you are also very new to LabVIEW (I know you are new to the LabVIEW Forum).  Here are some suggestions to both help you in getting started with LabVIEW and in helping us to help you:

• As you already know, LabVIEW programs are "graphical" -- in order for us to understand your code, we need to "see everything".
• The best way for us to view your LabVIEW program is for you to attach your LabVIEW Program (or even the entire LabVIEW Project).
• Because you are a new user, you might be using a "new" (i.e. 2025) version of LabVIEW.  Many of us are running a few versions behind, so before posting your code, consider using "Save for previous Version" (from the File menu) and choose LabVIEW 2019 or 2021.
• Do you know how Data Flow works?  Data flows in wires.  Structures (and functions) don't start running until all the "input wires" have data.  Structures/functions don't "release" (output) data until they finish.  Structures/functions don't finish until everything inside them has run.
• As a beginner using LabVIEW, do not use a Sequence Structure.  Especially, do not use a multi-layer Sequence Structure.  Use a Wire (or wires) instead!
• Do you know about the "mechanical action" of Boolean controls?  Note we can't tell from a "picture" if your booleans are "Latching" or not.  Was it a "Square Button" (like "OK" or "Stop"?  If so, it won't "Stay pushed" if your code is reading it.  If it is a "Push Button", it won't stay "Pushed" (unless you "hold it down" with your finger).
• If you are in a class, please talk to your instructor and work with your fellow students.  There are also LabVIEW tutorials (see the first page of this Forum, not to mention the Web).

Bob Schor

[crossrulz]

Most likely, your event case is set to "Lock panel until the event case completes". This mean the user cannot interact with the front panel until that event case is complete, keeping you from being able to press the button.

Architecturally, there should never be a "long" running task inside of an event case. A basic state machine may be good enough for what you are doing.

[altenbach]

We don't "do" pictures of code because it is impossible to see the whole picture (sic) 😄

All we can see is a lot of "code smell" (yes, pictures can smell)

• What is the mechanical action setting of the boolean control?
• What is the event configuration?
• What is in the other event cases?
• What is in the sequence frames we cannot see?
• Why is there no toplevel loop? Looks inside-out.
• Why are there so many pointless sequence structures and local variables? 

so please attach your actual VI and I am willing to take a look. I won't just widely guess because there can be tons of reasons. 

[billko]

---

@crossrulz wrote:

Most likely, your event case is set to "Lock panel until the event case completes". This mean the user cannot interact with the front panel until that event case is complete, keeping you from being able to press the button.

Architecturally, there should never be a "long" running task inside of an event case. A basic state machine may be good enough for what you are doing.

---

I see the "Lock panel until the event case completes" being frequently cited as the issue.  I prefer to think of that as a symptom and not the problem.  The real problem is simply that you aren't doing it right.

[leololo]

Hello, sorry yes I am new to Labview and this community. I got the main part of the code from a supervisor (which doesnt have time to explain anything further) and wanted to adapt this code. And apparently it went wrong 😄
I dont know why there are so many pointless local variables, i was just attempting to get my code running.
Here I will share it code, I hope that you can help me with the "Loop feeding".
Thanks a lot!

[Bob_Schor]

Please take enough of the LabVIEW Tutorials (see first page of the Forum, I think there's something called "Learn LabVIEW" or something similar).

Did you notice there are two "styles" of Boolean controls on your Front Panel?  Boolean controls have a "Mechanical Action" (there are 6 varieties of such actions).  If you right-click a Boolean control, you can examine its Mechanical Action properties, with a nice diagram that explains them.  Rectangular ones typically have "Latch when Released" -- this means that nothing happens until you release the button, at which point it stays "pressed" (or True) until you read it, when it resets to the "default state" (almost always "False").  This makes them ideal for Event structures -- if it triggers an Event, then it went from False to True, and them moment you read it in the Event structure, it resets itself to False (so you don't need a local variable to do that -- LabVIEW does it for you.

The Oval buttons, by default, are "Switch when Pressed".  That means, "one push to turn on, a second push to turn off".  (They also have a little Light that comes on to remind you to turn them off).  If you want them to turn themselves off, replace them with a Square Button (maybe the OK button), but give it a new name (Flush Chamber?) and edit its "image" so it says "Flush Chamber".

That's one small lesson.  Go learn more.

Bob Schor