Tachometer calibrating method for windscreen wiper, involves calculating correction coefficient of tachometer, where coefficient represents difference between nominal value and real value of shifting angle

摘要

The method involves rotating a magnetic ring (12) at a constant rotation speed, and measuring a time taken by the ring for carrying out a complete turn around its main axis (A). Another time taken by the ring for turning at an angle equal to a shifting angle between magnetic sensors (16, 18) e.g. hall effect sensors, is measured. A correction coefficient of a tachometer (10) is calculated based on measured time, where the coefficient represents a difference between a nominal value (beta) and real value (alpha) of the shifting angle.