How do I make a graph overplot until manually cleared?

[scoates]

I need to prevent the plot from clearing between updates. That is, the previous traces remain on the screen and the new data is drawn on top of it. How can this be accomplished?

[Mads]

Use a chart...

Charts have their own buffer and keep the previous X readings with X being the size of the buffer (adjustable). Graphs do not but often have other properties that makes them better to use than a chart, in such cases you need to make a buffer yourself and feed the graph with all the data in that buffer. Circular buffers are often the best option.

If you are not talking about points but trends and you want to keep the previous trends and just add another plot you'll need to build a 2D array of the plots and feed that array to the graph.