The invention relates to a sensor arrangement for scanning a scanning area (16, 36) comprising a scanner (10, 30, 42, 54) that generates a scanning field (12) which is defined between two legs spaced from each other by a scanning angle (A), and which scanner is adapted to control at least one blocking means (18, 38, 50) for a passageway (32, 56), said passageway (32, 56) being delimited at least in its horizontal extension. The invention is characterized in that a scanner (10, 30, 42, 54) is mounted at a distance, as viewed in the passage direction (14), from the passageway (32, 56) and thus also from the controlled blocking means (18, 38, 50), and that the scanning field (12) is directed towards the passageway and extends through the passageway (32, 56).