marking cursor points on an fft graph

[do-loop]

I'm trying to mark list of several peaks on an fft waveform graph and retain the points on the graph much like a commercial spectrum analyzer.  I have extracted the cursor coordinates with the property node and created the list.  My problem is that I want to show the cursor points on the graph and I just can't get it.  Any help is appreciated.

I'm using LV 7.1 with the express fft.

thanks in advance

do-loop

[G-Money]

do-loop,

            Post what you have so far so we might be able to help you better. So you need to be able to graph the initial data, get the peak values, then replot just those peak values or you want to sort of hightlight them on the same graph? The bad thing about graphs is they don't retain data between runs so if you tried to rewrite the data then the initial data would be gone. Charts and XY Graph Express can have memory to hold the values. Let me know and maybe we can find a solution for ya!!

[Cory_K]

You could try something like this. This will get the x and y value of the cursor.

Set up the loop so it gets the value whenever you want it (at maxiumums, or every N seconds, etc).

Then it will graph these points on an x-y graph. 

Message Edited by Cory K on 11-13-2008 11:22 AM

[do-loop]

G-Money,

Thank you for responding.  I'm trying to figure out how to post a png directly to the message.  Having trouble.  I will try to send the png as an attachment.

I have used the property node of the fft chart to pick off the cursor points and have put them in an array.  I am able to pick off the points and plot them to an xy chart.  What I can't do is plot the cursor points on the fft chart along with the fft waveform on the same graph indicator.  I suspect that I have to convert the dynamic signals to scalar arrays and plot them on an xy chart.  The problem is that the fft wants to reference time and the cursor points are xy coordinates.

I remember in very old versions of LabVIEW that  you could get multiple plots on a graph by overlaying the graphs on the front panel and either grouping or graying out the added plots.  That seems like extra trouble and not the right way to do it.

Thanks again

Do-loop