CPU overload in displaying with waveform graph

[labmaster]

My example code (yahoo.vi) shows the DBL 2D array in size of 30,000*2.

Whenever 2D array was displayed with waveform graph, I found there were big delay (around several seconds) by CPU overload though the measured time was very short.

Once happened this, the computer (PXI 8108 dual core, 4G memory, win7 32 bit) was slow to operate something.

Is it bug or just computer problem? or Have you a solution?

labmaster

My LV version is 2009.1 (installed service pack)

[Ben]

I think the issue is that you are trying to display 30,000 points using about 200 pixels so the CPU is crunching like crazy.

Reduce the data set size and you should be fine.

There is a white paper by Dr Gray that talks about large data sets and offers suggestions on how to dither down the data before trying to display. Search the site, its here somewhere.

Ben

[labmaster]

Thanks Ben,

I think 30,000 is not huge in DAQ.

Is it a ultimate limitation of LabVIEW?

[Ben]

I have done much higher many times and the limitaiton is not DAQ at all.

It is a limitation of your screen size.

You are trying to squeeze 30,000 lbs of sh$# into a 200 lbs bag!

Ben

[altenbach · Accepted solution]

You need to transpose the array! (or right-click the graph...transpose array)

You are graphing 30000 plots with two points each (hard!) instead of 2 plots with 30000 points each (easy!).

(Imagine you would display the plot legend with 30000 plots, it would be a mile high!)

[labmaster]

Thanks,

It was my mistake..

Labmaster