Sir,
I think that that function will work correctly, unless I am misunderstanding your question. Your call might look something like this:
status = SetAxisRange (panelHandle, PANEL_CHART, VAL_MANUAL, 5.0, 20.0, VAL_NO_CHANGE, 0.0, 1.0);
This manually sets the xmin and xmax values. Let me know if I am misunderstanding your issue.
Daniel McChane
Application Engineer
National Instruments