How to save a fixed time interval of dynamic data during continuous acquisition?

[Tomaz79]

Hi, maybe someone has an idea how to solve this:

I'm doing continuous acquisition of dynamic data and when I see something interesting, I'd like to save some of the data (i.e. the last 90 seconds). I guess the first step is writing the data into an array? Can I set up the array in such a way that it always contains just the last N seconds (or last N points, discarding the rest as the measurement goes along) so I can then save that data, for example by pressing a button (possibly without stopping the .vi, or maybe just pausing it. This last step is not crucial)?

Thanks for all the suggestions!

[MikeS81 · Accepted solution]

Hi Tomaz79,

you can build it like a black box in an aircraft. You can initialize an array with size of your 90 sec. Write all your data into this array with overwriting the specified index. With Quotient & Remainder you will get the correct index for the next value. If you find your interesting value, you can be sure you will have the last 90 secs.

Mike

[Coq_Rouge]

Do you use a waveform chart? If your amout of data or updatespeed permits it, here is something you can try. Anyway the function you are looking for is a FIFO. Do search for it here or at NI developer Zone 

[Tomaz79]

Guys, thanks for the suggestions. I was able to solve my problem with the array!