Patent ID: 6040779
Filing Date: 2000-03-21
Classification: G01D,G01L,G01R

Abstract:
A method for monitoring the function of a symmetrical sensor bridge circuit (1) having sensor elements (a, b, c, d), which are connected in a full bridge circuit and are supplied by a bridge supply voltagecharacterized by the following steps:derivation of a full bridge signal (V.sub.in) from the sensor bridge circuit;derivation of a half-bridge signal (V.sub.inp, V.sub.inn) from the positive or the negative half-bridge circuit;subtraction of the instantaneous level of the half-bridge signal (V.sub.inp, V.sub.inn) from half the bridge supply voltage (V.sub.s /2) while forming a difference signal (V.sub.inn -V.sub.s /2);amplification of the difference signal by a defined amplification factor (x), so that it corresponds to the full bridge signal (V.sub.in) if the sensor bridge circuit (1) operates correctly;comparison of the full bridge signal (V.sub.in) with the amplified difference signal; andgeneration of an alarm signal if the amplified difference signal deviates from the full bridge signal (V.sub.in) in an unacceptable manner.