Patent attributes
A closed loop control system for controlling a plant comprises a controller includes an input arranged to receive a feedback signal from the plant. The controller is arranged to compare a value of the feedback signal to a set point value x(s) and to produce an error signal ε(s) that is at least partially dependent on a difference between the value of the feedback signal and the set point value. The controller also includes an output arranged to supply the error signal ε(s) to the plant. A monitor is arranged to compare a value of the error signal ε(s) produced by the controller to a threshold value and to produce a warning signal when the value of the error signal ε(s) exceeds the threshold value for a period of time greater than a predetermined period.
