Add Static Boundary Lines to FFT Power Spectrum Waveform Graph in LabVIEW

Updated Nov 19, 2019

Reported In


  • LabVIEW

Issue Details

In LabVIEW, I am using the FFT Power Spectrum and PSD VI to plot a Waveform Graph. I have that running fine. However, I would like to add static boundary lines to the Waveform Graph in order to quickly see if the live data is staying within those lines. Is there a way to do this by reference just a couple of points on the graph? 


Here are potential options to adding boundary lines to the Waveform Graph:
  • Depending on your application, you can add in Cursors to your Graph  to signify boundary lines. Note: These lines have to be either horizontal or vertical (can not be angled) as well as will have extend across the entire graph.
  • If you need boundary lines that do not extend across the graph or lines that need to be angled, the attached Power Spectrum Lines .vi  shows an example of how to implement this with the FFT Power Spectrum Waveform Graph in LabVIEW. The example shows how to reference four points to create a boundary that is in the shape of the trapezoid. This can be edited to create boundary lines at the specific points you need them at. Note: The attached VI was created in LabVIEW 2018 SP1.