1. A method of avoiding oscillatory behavior in a PID controller in a closed-loop process, the method comprising the steps of: identifying an ultimate set of tuning parameters for the closed-loop process; observing an oscillatory behavior response in the closed-loop process; identifying a damped natural frequency from the oscillatory behavior response; identifying a damping ratio from the oscillatory behavior response; calculating a modified damped natural frequency from the damped natural frequency; calculating a modified damping ratio from the damping ratio; determining the degree of oscillation of the oscillatory behavior response and determining the leading cause of the oscillatory behavior response from the calculated modified damped natural frequency and the calculated modified damping ratio of the oscillatory behavior response; and adjusting the ultimate set of tuning parameters of the closed-loop process based upon the degree oscillation of the oscillatory behavior response the leading cause of the oscillatory behavior response, thereby avoiding oscillatory behavior in the PID controller.