Re : Variance of 20 Samples At a Time....

[johnsold]

You need to change the format string to %s for strings.

Have you worked through the tutorials?  Some of the problems you are having are fundamental LV concepts. Spending a few hours learingthe basics will save you much more than that in just the next few weeks.

Lynn

[simply_me]

To be honest I've not looked at LV tutorials on the subject because I know how to save numerical data to spreadsheet so I thought it'll be much of the same; I guess it's not. In my vi I pass an array of strings (each time stamp is an entry), and changing the format to '%s' didn't work nor I think it's what I need. 

Thank you for the input though, I'll definitely spend some time this weekend on LV tutorials. 

[simply_me]

Connecting string arrays after each case/loop, it seems that I don't output any entry in my array....

[johnsold]

Please post what you have tried.  It is almost impossible to guess what you are doing and why it does not work.

Lynn

[simply_me]

Here is the latest one.

Thank you for taking a look at it.

[johnsold · Accepted solution]

I do not understand all of your logic (thresholds and timing), but it seems to work for me.  I get very few points, so maybe that is where the problem is located.  Do you see data on the Time String array indicators and not in the file?

I cleaned up the diagram and reduced it to fit on my screen.  I eliminated the extra build array after the while loop and used the 1 D array input.  Index Array rather than a 1-element array subset and used scalars directly for comparison rather than dynamic data.

Generally use of Build Array in a loop is not good practice if the arrays may get large because it requires repeated memory reallocations.  Initialize the array outside the loop and use Replace Array Subset.

Lynn

[simply_me]

Hi Lynn,

Well, I want to implement this vi in a larger vi that does particle tracking/analysis, so to define a "jump" I collect a set of FPS/2 data points , check variance, and then differential if it's needed. It is important to time stamp the jumps in order to get characteristics. 

This vi implements the algorithm I use and works in the same manner as the functional requirements for the main vi, I just created this one for simplicity (without including IMAQ and other algo). 

I didn't know that build array in a loop recopies the entire array each time, I guess I"ll have to change my habits 🙂 I'll do the changes you've suggested. 

Thank you for your explanations & help, it seems to work great now. 

[simply_me]

Hi Lynn,

Well, I want to implement this vi in a larger vi that does particle tracking/analysis, so to define a "jump" I collect a set of FPS/2 data points , check variance, and then differential if it's needed. It is important to time stamp the jumps in order to get characteristics. 

This vi implements the algorithm I use and works in the same manner as the functional requirements for the main vi, I just created this one for simplicity (without including IMAQ and other algo). 

I didn't know that build array in a loop recopies the entire array each time, I guess I"ll have to change my habits 🙂 I'll do the changes you've suggested. 

Thank you for your explanations & help, it seems to work great now.