Patent ID: 9331682
Filing Date: 2016-05-03
CPC Classification: G01R,G05B,H03K

Claim Text:
1. A method of monitoring an analogue signal output from a sensor comprising: comparing an amplitude of the analogue signal to a first threshold pair, wherein the first threshold pair comprises a first high threshold and a first low threshold; setting a primary monitoring signal to a first value when the amplitude of the analogue signal exceeds the first high threshold; setting the primary monitoring signal to a second value when the amplitude of the analogue signal decreases below the first low threshold; comparing the amplitude of the analogue signal to a second threshold pair, wherein the second threshold pair comprises a second high threshold and a second low threshold and wherein the second high threshold is greater than the first high threshold and the second low threshold is less than the first low threshold; setting a secondary monitoring signal to a first value when the amplitude of the analogue signal exceeds the second high threshold; setting the secondary monitoring signal to a second value when the amplitude of the analogue signal decreases below the second low threshold; comparing the primary and secondary monitoring signals; and determining from the comparison of the primary and secondary monitoring signals whether an error exists with the monitoring of the analogue signal.