I understand how to plot in real time with an xy graph appending to an array, but I would like to simply put a line so I can see when my first plot crosses a certain value on the y-axis, say at like y=30. So I would like to know how it is you can plot two lines in real time. I'll put in my vi so you can take a look at what I have so far. On my vi the array is shortened to contain only 5 values so as not to take up memory.