Device for sensing a rotary member such as a water meter turbine

摘要

A device for sensing the rotation of a member rotating about an axis XX' comprises m proximity sensors situated in a plane perpendicular to the axis XX' and in m radial directions, m being an integer greater than or equal to 2. A mark fastened to the rotary member and eccentric to the axis XX' modifies the amplitude response of the proximity sensors when the rotary member rotates. An excitation circuit excites the proximity sensors, each sensor supplying an excitation response when it is excited. The amplitude of the excitation response of each of the sensors is compared with a comparison threshold value during a time period referred to as an observation window to supply a logic level 1 or 0 according to whether the response amplitude is greater than or less than the comparison threshold value. The movement of the mark past one of the sensors is identified as a function of the value 0 or 1 of said logic level. The comparison threshold value or the observation window characteristic of a sensor L 0 , L 1 is reset by means of successive iterations using the value 0 or 1 of the logic level when the mark cannot be at the location of the sensor.