Passive capacitive sensor's i.e. piezoelectric accelerometer sensor, operation failure detecting method, involves comparing measured and nominal capacities, where variation between capacities above preset threshold indicates failure of cell

摘要

The method involves generating a periodic reference signal (5), and injecting the reference signal to terminals (6, 7) of a measurement cell (1) i.e. piezoelectric accelerometer used as an engine noise sensor. A capacity of the measurement cell is measured at the terminals, and the measured capacity is compared with a nominal capacity. A variation between the measured capacity and the nominal capacity beyond a determined threshold indicates a failure of the measurement cell of a passive capacity sensor. An independent claim is also included for a device for detecting operation failure of a sensor.