I am using FREE version of orcad 16.6. I tried to use curve fitter from PSpice advanced analysis section, for a simple RL circuit driven by a VSIN source. But whenever I try to use curve fitter, I find no parameters to vary. No circuit component is shown there in the select parameters option; although that circuit got two of them( R and L, to vary). Is it something to do with the FREE version? Or am I turning the wrong stone?