The frequently used automatic rack control units make modern warehousing much easier. These units must automatically travel long distances and position the products with millimetre precision at the end. Modern optical laser sensors and also draw-wire sensors are used to monitor this movement. Draw-wire sensors are the more economical solution for distances up to 50 metres. Laser sensors which determine the distance using time of flight measurement are suitable for larger distances. Distances can be precisely measured and loads can be exactly positioned or delivered with their help.