Hello,
I am plotting MIC (Minimum inhibitory concentration) data. Data should be fitted to Gompertz model. Such model exists in OriginPro, however, usually doesn't work.
Example of data:
Error that occurs below:
(1) Parameter Initialization was called.
(2) Parameter Initialization was called.
(3) Parameter Initialization was called.
(4) ---------------Chi-Square---------------
Reduced Chi-sqr = 591.093861463
(5) -----Orthogonal Distance Regression-----
Reduced Chi-sqr = 115.76659027
COD(R^2) = 0.41875347893492
Iterations Performed = 2
Total Iterations in Session = 2
(6) Fit did not converge - reason unknown.
Fitting was done with weights. Check weighting method and error bar values for possible inconsistencies, or try fitting again with weights turned off.
And this is for every data I use. I noticed that this model is called in OriginPro "SGompertz" and not "Gompertz".
The model in OriginPro seems the same to me as the one that works in other program that I use for plotting:
EQUATION:
M=logMIC - 1/Slope
Y= Bottom + Span*exp(-1*exp(Slope*(X-M)))
I have no idea why the fitting is not working in OriginPro. And that's a pity as I cad (and do!) process every of my data in OriginPro except MIC data...
Can anyone please help me to locate the problem and tell me how to solve it 
I am not really good at programming etc. and Origin is still after almost 5 years a mystery to me in some aspects... :P
