Labeling peaks and valleys above or below an assigned threshhold

[rob_saner]

Hello everybody,

I am very new to labview and am trying to assign marker points on a graph to the true peaks and valleys that are above or below a threshhold chosen by the user. Say for example that my graph is produced from a spreadsheet of 30 numbers and I am told to set a threshold of +10. I need the graph to show a red marker for all the peaks above 10 that occur along the graph. Could somebody please advise me on how to achieve this? 

Many Thanks!

[Kyle97330]

How much have you done so far?

Graphs in LabVIEW can have multiple plots per graph, and each plot can be a different style.  If you set up an X-Y graph to show all the data points connected by lines on plot #0 and show the peak locations as unconnected red points for plot #1, that's your display method.

As for detecting the actual peaks, you can either do the math yourself or there's a built-in VI you can try to use.  

Programming -> Waveform -> Analog Waveform -> Measurements -> Waveform Monitoring -> Waveform peak measurement

We're not going to do all of your work for you, so please try to produce something yourself (even if it doesn't work), and then post the VI along with a description of what specifically isn't working.  Make sure a set of sample data is included in the saved VI.

[rob_saner]

Hey there,

Thanks so much for replying. So far I have completed the following on my block diagram (see attached pics). When I try to create an x-y graph for an indicator, it says "Labview cannot replace the current control with a composite control".

[udka]

You must be trying with Express XY Graph, Try replacing with XY Graph :http://digital.ni.com/public.nsf/allkb/F1980F17F8EC917686257405007838C6

P.S. If you post code it would be nice with the error encountered and not some images.