Patent US 4,054,780

In a process control system, a control signal to the process is provided to a process model having a predictive element and a delay element adapted to reproduce as closely as possible the action of the measured process variable to the control signal. The variable input signal to the process controller, upon which generation of the process control signal is based, is generated by multiplying the signal from the predictive portion of the process model by a correction factor generated in response to the ratio of the actual process measurement signal to the delayed model output signal.