Arrangement for determining piston rod position converts receiver output signal amplitude modulated by distance marker contrast pattern into binary signal sequence using threshold

摘要

The arrangement has displacement markers (7) arranged along the piston rod (4) with alternating contrast patterns, an optical sensor with a transmitter and receiver and an evaluation unit. Markers are scanned by the optical transmitter beam (9) as the piston moves. Light reflected at the markers is received. The receiver output signal is amplitude modulated by the contrast pattern and is converted into a binary signal sequence using a threshold.