System for detection of the position of the closing leaf for a barrier during its handling

A system for detecting movement conditions of a leaf closing a barrier, the leaf being able to occlude a delimited opening or passage and in which the leaf is moved by a motor having a first rotation shaft is associated with a motion transmission mechanism to the leaf, the system comprising:

• a first measuring device provided on the motor, the first measuring device configured to measure rotation of said first rotation shaft, and
• a second measuring device associated with a second rotation shaft, said second rotation shaft being connected to the first rotation shaft by a reduction gear having a reduction ratio that is non-integer,
• wherein when one of the first and second rotation shafts performs an integer number of revolutions, the other of the first and second rotation shafts performs a predetermined number of revolutions plus or minus a phase shift angle due to an effect of the non-integer reduction ratio, the phase shift angle containing an indication of how many integer number of revolutions the one of the first and second rotation shafts has performed, and
• wherein, when the phase shift angle is measured in revolutions, a decimal part of the phase shift angle indicates the integer number of revolutions made by the one of the first and second rotation shafts.