DAQ voltage threshold for a specific time

[Yashwant]

Hi,

Being a newbie to Labview, I'm finding it a little bit hard to get things done.  Here's what I want: I'm acquiring voltage values from a voltage source through DAQ in a while loop. Once the voltage reaches, say 4.8V, I want it to remain above 4.8V for a specfied time, say 5 seconds. If it does, I will perform some action. Until this happens, I will keep sampling the values. I had a look at some examples but none of them do what I intend to do. . Can someone also point me to where I need to look for similar questions in future?

[mikeporter]

One thing you could do is put a shift register on the acquisition loop. Inside the actuisition loop, if the input value from the DAQ is less than the threshold, write the current time in seconds to the shift register. If the input value is above the threshold put the old value back into the shift register and subtract the contents of the shift register from the current time. If the difference is greater than 5 seconds, do what you need to do next.

Mike...

Message Edited by mikeporter on 02-11-2009 11:55 PM

[MattBradley · Accepted solution]

Not to argue with mike (who is far better at this than me), but here is how I would do it....  where the Take Data vi is where you get your data...

-Matt

[Yashwant]

My sincere thanks to both of you. I could do it using the method that Matt described as I thought that was easy. Please find how I did it in the attached file.

-Yashwant