Make a waveform chart not automatically drag the x scrollbar cursor

[Fibo]

Hello,

I'm using a waveform chart to record data, I have it with a 10 minute buffer, I want to be able to scroll back on the x-axis and look at data that was taken a few minutes ago... I want to be able to let go of the mouse and not have the cursor fly back to the current time.... is this possible?

Thank you! 

[GrahamG]

one way to do it would be to create your own chart out of a chart like the below vi. I think this is the best way

if you need to use the chart for some of its other features then you can look at using property nodes but the update rates needed for this do not give it a very responsive feel.

Have a look and see what you think

best regards

[GrahamG]

create a chart out of a graph - sorry just read what I typed.

🙂

[chilly_charly]

This is my Christmas gift ...  Hope it's not too buggy.

It uses a functionnal global to create a buffer that stores the Y data (init, read, write, resize). The buffer size can be modified at run time without loosing data (well... as long as you don't decrease the size of a full buffer... a better behaviour than the LabVIEW waveform chart). The default size is 1024 points.

The X axis update is managed separately (because I'll reuse the buffer global for other applications... 😉 ) 

Enjoy ! 🙂

Message Edité par chilly charly le 12-23-2008 03:18 PM

[Fibo]

this looks good, but.. I wish I could open it, I'm using LV 8.5, it's an 8.6 file.  could i get an 8.5 version?

much thanks! 

[Juan G]

Done!

Juan Galindo

Applications Engineering

National Instruments

[Fibo]

Thanks for the vi chilly.  So, I notice that in your vi your waveform graph is labeled as "Waveform Graph/Chart" but I can't get it to work with a "Waveform Chart" whenever I try to plug in a Waveform Chart reference into the Update X axis VI I get conflicting types and it doesn't let me wire into it... does this solution only work for waveform graphs and not waveform charts?

much thanks! 

[Fibo]

I have another question... in trying to use Chilly's solution, using a waveform graph... how can I wire more data into the graph?  I have been using a merge signals VI to combine a bunch of data together (I'm plotting 6 numeric outputs from a DAQ) to be plotted on the waveform graph... but that doesn't work with the Dealy VI.  Thanks!

[chilly_charly]

The proposed VI was not intended as a universal solution, able to reproduce all the functionnalities of a native chart. However, you should be able to modify it to accept multiple data points. Open and modify the buffer subVI.