LabVIEW
Digital output
Solved!
Hi John,
Well, you came pretty close to duplicating my code, anyway...why all the extra "merge error" functions after the loops stop? And what did I tell you about straightening out your wires? It's important. My head aches when I look at your code. 
Minimizing wire bends and having everything in straight lines makes the block diagram a lot more readable. Every time I modify your code, I have to spend several minutes going through and straightening everything, out, removing empty space so that the block diagram fits on the screen without having to scroll, etc.
The block diagram shouldn't exceed the screen size...or, at worst, you should only have to scroll in one direction. You're probably going, "ok, ok, quit harping on this and solve my problem", but it really does matter, especially when someone else is trying to read your code.
Merely a small scolding.
Ok. On to the code.
To be honest, I cannot tell from your description exactly what you want your "stop" condition to be.
Here is what I think you want:
1. Start both operations. Both loops running.
2. Input signal in bottom loop goes T. Top loop continues to run.
3. After x seconds, input signal in bottom loop goes F. Both loops stop (or top loop essentially goes idle).
3a. Input signal in top loop goes T. Both loops stop.
3b. "Stop" button pressed. Both loops stop.
3c. Error occurs in either loop. Both loops stop.
Have I interpreted this correctly? If the top loop goes idle, what starts it running again? A button press? An input signal? Does the bottom loop ever go idle?
You should really start thinking about converting this to a state machine. It will tidy up the code and allow for much greater flexibility for future modifications. Search the forum for "state machine". You will get a LOT of hits. Look up event structures, too.
In fact, I think it would be good for you to sit down and write out precisely what you want this program to do, step by step (like I did in my first response). I feel like the specifications keep changing, which makes it very difficult to steer you in the proper direction. You want to wind up with a good, maintainable program. To get there with a minimum of fuss, you need to start by outlining everything you want it to do.
Hey Diane
Finally i got that Vi finished and doing what we wanted. Tens of hrs for 3/4 extra icons :smileyfrustrated 
I am sure it is not written correctly (if that is what you can say about labview "written" ) but it works. Anyways i want to thanks you for everything you have done for me over the last few days, you really helped a newbie get a better understanding of labview.
I have attached the vi for your information.
Thanks for everything
Regards
John
Hi John,
There are other, more flexible ways you can do things, but if this is working for you, go with it. It might be kind of a pain if you ever want to expand it, but you can always start another thread for that.
Your use of a local variable is fine in this case since you only have one place where you write to it (I'm not sure why you write to a local and then read from the terminal instead of writing to the terminal and reading from the local, but that's really neither here nor there), but I would encourage you to use locals sparingly and with caution. Search "race conditions" on this forum to find out why I say that.
If you are serious about wanting to really learn LabVIEW, then do spend some time going through the introduction courses I directed you to earlier in this thread, and look at different architectures like state machines, producer/consumer, etc. I think you have good potential so I'd like to see you getting into good programming habits early! That, and you'll wind up with much better code. 
You've done a good job and I'm glad I was able to help.
Diane
