METHOD AND INSTALLATION FOR DETERMINING A RELATIVE DISTANCE IN A CYLINDER AND PISTON DEVICE

摘要

In the method and installation for determining a relative distance between the front wall (22) of the cylinder and the piston (14), an ultrasonic converter (30) is used to which a plate (68) presenting a reflecting reference surface (66) for the formation of a reference path is secured. The group of reference oscillations (R) and the group of measurement oscillations (M) appearing in the output signal of the converter (30) after the emission of a group of transmitter oscillations (S) are detected by means of threshold switches (108, 120, 122). Thereby, a measurement signal and a reference signal are obtained, the latter being used for compensation by means of a processor (38) of the influences of the different propagation conditions of ultrasons affecting the measurement signal.