Feedback controller

Abstract

A closed loop feedback control system that operates to maintain a process variable at or near a process variable setpoint. The system includes a setpoint regulator that adjusts the value of a process variable in response to a setpoint associated therewith. A sensor associated with the setpoint regulator senses the process variable and outputs a process variable signal corresponding thereto. A controller connected to both the setpoint regulator and the sensor in a closed loop is programmed with PID logic to control operation of the setpoint regulator in response to the process variable signal received from the sensor. The controller generates a control signal that controls the setpoint regulator based on a non-uniform two-point sampling of the process variable signal. The controller delivers smooth, bump-free, control in spite of changes in the setpoint controller gains or system parameters. A digital filter is also implemented with the controller of the present invention to filter the process variable signal input into the controller. The filter includes both an amplitude to clip signal spikes and glitches and a low pass frequency filter to remove higher order noise-related frequencies from the signal, thereby reducing system memory requirements and increasing system computational speed.

Dependencies are inferred from the claim text.