Patent ID: 6556957
Filing Date: 2003-04-29
Classification: G08B

Abstract:
A method for detecting an alarm state in a signal while avoiding false alarms from gradual signal drifts and outlier measurements, comprising:obtaining a measurement value of the signal at a current time; determining a position parameter and a deviation parameter from previous measurement values of the signal that were measured during a time window, wherein the time window is offset in time by an adjustable time delay from the current time; computing at least one of an evaluation quantity, an alarm threshold, and an outlier threshold based on the measurement value, the position parameter, and the deviation parameter; and indicating an alarm state in response to the evaluation quantity exceeding the alarm threshold but not the outlier threshold, wherein the measurement value is determined to be an outlier measurement if the evaluation quantity exceeds the outlier threshold, whereby the alarm state indicates a significant drift or jump of the signal.