The transmitter generates infra-red light beams flashing at high speed in synchronous action. The parallel light beams with a spacing of 7,5mm or 14,3mm are monitored by miocro-controllers. The receiver evaluated the arriving beams in synchronous action to the transmitter.
Due to the closeness of the beams, a resolution of 14 mm / 30 mm is achieved. If an obstacle is placed into the protective field, i.e. at least iner lieght beam is interrupted, the hazardous movement of the machine is stopped, i.e. a new start is not possible.