Mixed signal graph can't display both xy and waveform

[E85guy]

I want to display an xy signal and a waveform signal together on a mixed signal graph. I have bundled the two signals and connected the output cluster to the graph input. There are no errors indicated and both signals are listed together in the same group on the graph legend. When I run the VI, only the XY signal appears on the graph. The waveform signal appears on the mixed signal graph if I wire it directly to the graph input (no bundle connected), so I know the signal is OK. 

Shouldn't it be possible to display both signals on a mixed signal graph in the same group, even though they are different types, different number of points, etc.?

[JCH_26]

Hi E85guy,

My name is Jonathan and i work within the Applications Engineering Department at NI in the UK. 

I have had a go at creating mixed signbal graphs myself using the bundle function and I found that the specific ordering and type of bundling before outputting to the graph as a cluster is very important, i believe the issues you are experiencing are due to the nature of the timestamp on the waveform data in comparison toi the XY data. 

I have produced a VI using the 'Waveform data to XY pairs low level VI' function to be able to the bundle the XY data together and ouput to a mixed signal graph, this example has worked and both the waveform data and XY outpuyt are displayed on the graph so I would suggest checking out the example i will attach and then to apply the technique to your application.

If you have any further queries about this issue please message back with your code so I can have a look at it to help resolve it further. I hope this rectifies you problem! 

Cheers

Jonathan

[E85guy]

Thanks so much Jonathan,

In the first place, it's good to know that there is actually something a little difficult about what I am trying to do!

Unfortunately, I can't open your example because I'm using Labview 8.2. I've had it on my computer for years, and I'm trying to re-learn Labview and see what I can do with it before I invest in upgrades.

Specifically, the problem I'm trying to address involves involves taking dynamic data from the DAQ Assistant express VI, filtering it with the Filter express VI, then processing it with the peak detect VI. I bundle the peaks and locations outputs from the peak detect VI to make XY plots. That works fine, but I'd like to overplot these peak values with the original waveform so I can monitor exactly how well it is working with complex waveform shapes. It seems to me that overplotting a waveform and the output of a waveform analysis VI would be a common thing to do, but apparently it's not as simple as just hooking them up to a mixed signal graph.

Could you send me an image of your block diagram, along with an explanation?

[Kaleb_A]

E85guy,

I've attached an example for LabVIEW 8.2 in which I've tried to replicate what you are doing. Hopefully you are able to open it. You can just replace the Simulate Signal Express VI with the DAQ Assistant.

Here is some more details about the different kinds of graphs and charts and their functionalities. http://zone.ni.com/reference/en-XX/help/371361J-01/lvconcepts/types_of_graphs_and_charts/

Best Regards,

[JCH_26]

Hi E85Guy,

Aplologies, I should have asked you what version you were using!

Ive attached some screenshots but Mr Andersons VI may be something better suited to your version of LV.

Hope this helps!

Cheers

J

[E85guy]

Thanks to Mr. Anderson and Jonathan for their help. Neither solution was exactly what I needed (mainly because I didn't ask the right question!), but I learned from both and eventually found a solution.

First, I was trying to use the "mixed signal" graph because I had the impression that it would enable me to plot a waveform (actually dynamic data)  together with an xy array (with uneven dts and fewer points). It doesn't!

What I really needed was to convert the dynamic data to xy and plot them both on an xy graph. This was trickier than I expected, because things like the waveform pairs to xy pairs VI output timestamp data for the x array. I'm doing 1 second buffers with my DAQ, so I wanted repetative 0-1 second "sweeps" on my graphs. 

My solution isn't very elegant, but it worked. To make an x array I used the initialize array VI.  I used the get waveform components VI to get dt, and used it as the element input for the array. I connected the buffer size from my DAQ assistant VI to the dimension size input of the array. Then (after converting the array to dynamic data) I used the Summation express VI to make a 0-1 second time signal for the xy graph.

Thanks for making me aware of the Build XY graph express VI. It is sort of hidden, given that you have to put an express xy graph on the front panel to get it into the block diagram. I would have expected to find it in the functions palette!

Thanks again!