A revolution counter includes a single sensor which scans movement of a
rotary element and generates a raw signal commensurate with a rotary
position of the rotary element for ascertaining one of at least three
areas of angular ranges. Two of these areas include each a single
continuous angular range, whereas a third area includes at least two
angular ranges, which interrelate but are separated from one another. A
power generation system delivers energy pulses to the sensor, when the
rotary element rotates below a minimum value, so that a raw signal can be
detected and the corresponding angular range area can be determined. The
power generation system and the rotary element are so interconnected as to
ascertain for at least part of the thus determined areas of angular
ranges, by which of the angular ranges the rotary element is rotated, and
to establish the number of revolutions based on the ascertained angular
ranges.
