Honeywell G.m.b.h.

Weston Instruments, Inc.

Frank Lynch

Theodore B Bozarth

Joseph L Lehmann

Anthony M Demark

Edward F Finn

A process control system including a method of suppressing overshoot of a process variable beyond the process value setpoint by predicting the overshoot by observing a waveform associated with the process variable, observing the waveform associated with the process variable, without regard to time scale or to amplitude scale, taking corrective action to reduce or eliminate said overshoot by utilizing a fuzzy logic module with a proportional integral derivative control to take corrective action of the process variable.

Method of predicting overshoot in a control system response

A sensor communication system uses a shared analog signal to duty cycle converter for producing a comparison between a predetermined free-running triangular waveshape and a selected output signal from a plurality of analog signal sources such as process sensors, to convert the amplitude of the analog signal to a variable duty cycle signal. The variable duty cycle signal is subsequently converted to a digital signal which may be represented by a count stored in a counter counting clock pulses during the occurrence of the pulse width waveshape of the variable duty cycle signal. The digital signal is utilized as a digital word by a microprocessor operating in accordance with a stored program to produce a characterized digital output signal for use in a communication after conversion to a 4-20 ma control signal for communication and control in an industrial process control system. One of the signal sources may be from a circuit having temperature and time drift components whereby the corresponding digital word is used by the microprocessor to compensate the digital words from the other analog signal sources.

Sensor communication system

A digital frequency-lock circuit has a binary rate multiplier connected between a fixed frequency oscillator and an output terminal to modify the oscillator output signal in accordance with a digital word. An up/down counter is arranged to supply the digital word to the rate multiplier in accordance with a count stored in the counter. The frequency of the rate multiplier output is compared with an input signal frequency during a cycle of the input signal to maintain a predetermined relationship between the compared frequencies.

Digital frequency-lock circuit

A fully digital spectrum analyzer accepting as an input either an analog signal or a series of digital numbers and using time compression and DFT (Discrete Fourier Transform) techniques to provide the spectral component values of the input signal. Novel techniques and means are used in obtaining the power values for selected spectral lines and in averaging these power values. Statistically controlled noise is added to the input of the spectrum analyzer to enhance its resolution beyond the resolution which would be otherwise available. Advanced and efficient techniques are used for generating and applying trigonometric functions in the course of finding the real and imaginary part of Fourier transforms, and for providing running averages of the power spectra.

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Hatboro, PA, United States of America

Frank Lynch