Method for fill level measurement using the travel time principle

Abstract

A method for measuring a fill level of a fill substance in a container with a fill-level measuring device working according to the travel time principle. The fill-level measuring device in measurement operation sends transmission signals toward the fill substance in the container and, based on their signal fractions reflected back in the container, derives echo functions, which give the amplitudes of the signal fractions as a function of their travel time. With the assistance of a table, whose rows correspond to discrete fill levels and whose columns correspond to discrete travel times, and in which are stored as historical measurement points, in each case, in that row, whose row index corresponds to the associated fill level, information derived from echo functions derived in the past concerning travel times of echo function maxima attributed to reflections on reflectors located in the container, that also delivers reliable measurement results, when measuring conditions at the location of use of the fill-level measuring device can change, wherein the table is continuously updated based on current echo functions derived in ongoing measurement operation, wherein current measurement points derived from current echo functions are stored.