Patent ID: 6466889
Filing Date: 2002-10-15
Classification: G01B,G01D

Abstract:
A method for determining an absolute position of first and second sensors, said sensors being mechanically coupled to each other, said first sensor generating an output signal having a first number of periods within a measuring range, said second sensor generating an output signal having a second number of periods within the measuring range, said first and second numbers of periods differing by one, said method comprising the steps of;comparing the output signals of the first and second sensors; generating a difference signal representative of the comparison of tile output signals; adjusting the difference signal when the difference signal is negative by adding a first predetermined value thereto; determining an integer approximation of the adjusted difference signal multiplied by the first number of periods and divided by the measuring range; generating a period number signal by multiplying the integer approximation by the measuring range; generating an absolute output signal representative of the absolute position of the first and second sensors by adding the output signal of the first sensor to the period number signal; generating an auxiliary signal as a function of the absolute output signal, said auxiliary signal being based on a difference between the absolute output signal and the adjusted difference signal multiplied by the first number of periods; determining whether the auxiliary signal is within a predetermined range; and adjusting the absolute output signal when the auxiliary signal is outside the predetermined range by adding a second predetermined value thereto.