The navigate plugin has a 'zoomRange' axis option that should accomplish what you want. See the comments at the top of the
for more info.
Resetting the plot depends on what exactly you're trying to reset. Are you introducing new data? If so, you can call setData, setupGrid, then draw. If you simply want to redraw without changing the data, then draw is all you need to call. The
docs describe how those functions work, and the
real-time updates example shows it in action. You could also just call $.plot again on the same element.