How do I use the locks on the curve fit parameters to get a stubborn curve fit to converge? For curve fits that have a difficult time converging, it can be helpful to get the fit algorithm a good initial guess. These initial guesses can be determined by taking measurements from an exported scope trace displayed within the graph display environment. The better "guessed" parameters can then be locked, to pull the unknown parameters closer to a space with a convergent solution can be determined. The locks on the remaining parameters can then be sequentially removed to produce a curve fit where each of the parameters are allowed to converge to the solution.