Patent ID: 6369583
Filing Date: 2002-04-09
Classification: B60G,G01D

Abstract:
A method for determining the distance of two reference points, which are movable relative to each other between a lower distance limit and an upper distance limit, with a sensor having a measuring range subdivided into several successive measurement value intervals, said sensor outputting a signal with each of said measurement value intervals having the same signal interval assigned thereto, the method being based on the following: the sensor is positioned in a defined position to both of said reference points in such a manner that all possible distances of said reference points correspond to the measurement values of one of said measurement value intervals; said sensor indicates a lower limit signal at said lower distance limit and an upper limit signal at said upper distance limit; said sensor indicates a signal between said lower and upper limit signals when said distance of said reference points lies between said lower and upper distance limits; and, a conclusion is drawn from said signal indicated by said sensor as to the distance of said reference points; the method comprising:(a) the following steps for calibrating said sensor: mounting said sensor as close as possible to said defined position relative to said two reference points; and, within at least one distance between said reference points, determining the difference of a signal, which a sensor would indicate if disposed at said defined position, and a signal (S) indicated by said sensor and determining an offset (O) from said difference; and, (b) the following additional steps for determining the distance of said two reference points: adding said offset (O) to said signal (S) indicated by said sensor to form a summation signal (SS=S+O); assigning the distance of said reference points to said summation signal (SS), which distance would be assigned to the same equally large signal, which a sensor would indicate if disposed at said defined position, when said summation signal (SS) lies between the lower limit signal Smin and the upper limit signal Smax; determining the distance of said reference points from said summation signal (SS) as follows when said summation signal (SS) lies outside of the signal interval from said lower limit signal Smin to said upper limit signal Smax: when said summation signal (SS) lies above the upper limit signal Smax, assigning a distance of said reference points to said summation signal (SS) which lies in the vicinity of or corresponds to said lower distance limit (hmin); and, when said summation signal (SS) lies below said lower limit signal (Smin), assigning a distance of said reference points to said summation signal (SS) which lies in the vicinity of or corresponds to said upper distance limit (hmax).