The invention relates to the idea of not initially multiplying the output signal (a) of an acceleration sensor (19) with regard to a weighted sum (_g) with a correction factor (k_w) but to alter a test signal (t) by using a weighting means (16) in such a manner that an already weighted output signal (a_g) can be generated so that during a test operation, the safing algorithm of an evaluating device can be directly fallen back upon, whereby this can be advantageously tested with regard to its ability to operate. The invention is particularly suited for occupant protection systems of a modern motor vehicle.