Hello.
Yes, it is possible to have two different vertical scales on an xy graph. There is no way that I know of to add a scale programmatically, but once you have added it, you can configure the range of it programmatically, as well as assigning a plot to any particular scale. You do this by using an xy-graph property node, with the properties YScale.Minimum, YScale.Minimum, and Plot.YScaleIndex respectively.