If your ramp is spaced equally in X, you don't need an xy graph. Just feed the ramp containing the Y values to a waveform graph and adjust x0 and dx of the x-axis as desired. You only need an xy graph if the x-value spacing is not uniform.
You can for example generate a ramp array using "signal processing ..signal generation...ramp pattern".
It would help if you could explain in a few more sentences exactly what you need. Maybe attach a drawing or small VI.