Thanks for all the help, I finished the program, follow the download link and a brief explanation of the same (in Portuguese, my native language), I apologize again for my bad english and any inconvenience that I have generated.
http://mundodacana.blogspot.com.br/2013/11/programa-para-calculo-de-constantes-pid.html Python commands :D -- https://mail.python.org/mailman/listinfo/python-list
