Historical Data Display

[zezendapuss]

I find 100 peaks per second from continuously acquired data and would like to display a histogram of these peaks for atleast 30 min. That would be 180000 data points.

At the moment i can only think of a Waveform chart with chart history length set to desired data points. Are these too many data points, performance wise?

What are my other options?

[GerdW]

Hi zezenda,

why would you use a chart just to store some data? (A chart is an indicator, meant to present data to a user!)

Why not use a shift register holding an array of your values? (You could even predefine this array in size as you seem to know sample rate and measurement time in advance!)

[zezendapuss]

Thanks you Gerd. I would also like to display all these peaks of last 30 min, thats why thought of a chart.

[GerdW]

Hi zezenda,

you surely talk about "samples", not "peaks"! (To show "peaks" you would need a lot more "samples"…)

It doesn't make sense to show 180k samples in a ~500pixel wide display: each pixel would represent 360 samples. It would make more sense to decimate the data for display and to show only "extraordinary" events…

[zezendapuss]

Sorry i am not clear enough. I do want to show only peaks. I am acquiring at a much higher sampling rate, detecting peaks of interest and would like to display them in a histogram for 30 min, to get an idea of how peak amplitude and/or frequency changes over time.

[CoastalMaineBird]

Check out my article: Monster Panel, Part V

Especially if you have multiple channels, you do NOT want to use a chart.

The article explains how to use a graph to:

--- switch channels and get prior history for the new channel.

--- get variable-length history.

--- update the graph properly as data comes in.

[zezendapuss]

I am generating an array of defined size and creating a histogram of the values. Now the histogram shows values from each loop iteration. I would like to have data from all the iterations appended continuously in a kind of waveform chart for a certain amount of time.

[GerdW]

Hi zezenda,

why are you doing this all that complicated? (And why did you start a new thread?)

I replaced your generic histogram with its Pt-By-Pt counterpart…

Edit: I forgot to set a reasonable "sample size" for this function!

[zezendapuss]

Thank you for this but how do i display a dynamic histogram which is updated continuosly for 30 min?