Abstract: A light barrier having at least one transmitter (6) and at least one receiver (8) for a light beam and having a light path (1), which runs between a first side (2) and a second side (4) of a region to be monitored, can be produced flexibly and with little complexity by virtue of the transmitter (6) and of the receiver (8) being situated on the first side (2) and by virtue of the second side (4) containing an optical system (10) which picks up the primary light beam (7) emitted by the transmitter and which deflects the primary light beam (7) and returns it to the receiver (8) via the light path (1) to the first side (2) as a secondary light beam (9), which is separate from the primary light beam (7), at a distance from the primary light beam (7).

Abstract: Pulsed operation of a light barrier that can be operated in a normal mode and in a compensation mode includes repeating a cycle of transmitting electromagnetic radiation over a transmission period recording measured radiation values at various measurement times and establishing whether extraneous light is incident on the detector by examining a measured value curve of the recorded measured radiation values. The respectively next cycle in the normal mode being run through when no extraneous light is incident, and in the compensation mode when extraneous light is incident, at least one compensation measure being carried out in the compensation mode in order to compensate the influence of extraneous light.

Abstract: The invention relates to a photoelectric barrier with a transmission device (2) for the transmission of a beam of electromagnetic radiation along a first path (6), a diverter for diverting the transmitted beam of electromagnetic radiation from the first path (6) onto a second path (12), and a reception device (16) for receiving the beam of electromagnetic radiation, characterized by the fact that the diverter is designed for a diversion that retains the beam's constellation relative to a plane containing the first path (6) and the second path (12).

Abstract: The invention relates to a method for pulsed operation of a light barrier that can be operated in a normal mode and in a compensation mode, there being run through repeatedly a cycle that comprises the following steps: a) transmitting electromagnetic radiation over a transmission period ttransmit by means of a transmission device (2), b) recording measured radiation values Ii of the electromagnetic radiation at various measurement times tmeas (24) within the measurement period ttransmit by means of a detector (4), and c) establishing whether extraneous light is incident on the detector (4) by examining a measured value curve of the recorded measured radiation values Ii, the respectively next cycle in the normal mode being run through when no extraneous light is incident, and in the compensation mode when extraneous light is incident, at least one compensation measure being carried out in the compensation mode in order to compensate the influence of extraneous light.

Abstract: A light barrier having a signal path (1) between a first transceiver arrangement (2), emitting a signal beam (4), and a mirror, returning the incident signal beam (4), allows reliable operation even when the length is great and under changing ambient conditions by virtue of the mirror being in the form of a second transceiver arrangement (3) and by virtue of both transceiver arrangements (2, 3) having a receiver (6), a controllable and encodable transmitter (8) and an evaluation and control device (7), connected to the receiver (6), for evaluating the intensity and an encoding of the received signal beam (4, 5), and for controlling the intensity and encoding of the emitted signal beam (4, 5), wherein the encoding is performed using a piece of information about the intensity of the received signal beam (4, 5).

Abstract: A light barrier having at least one transmitter (6) and at least one receiver (8) for a light beam and having a light path (1), which runs between a first side (2) and a second side (4) of a region to be monitored, can be produced flexibly and with little complexity by virtue of the transmitter (6) and of the receiver (8) being situated on the first side (2) and by virtue of the second side (4) containing an optical system (10) which picks up the primary light beam (7) emitted by the transmitter and which deflects the primary light beam (7) and returns it to the receiver (8) via the light path (1) to the first side (2) as a secondary light beam (9), which is separate from the primary light beam (7), at a distance from the primary light beam (7).

Abstract: A light switching device has a transmitter for generating light, a control circuit for controlling the light transmitted by said transmitter and a receiver for receiving the transmitted light. The receiver generates an indication signal which varies with the intensity of the received light. The device includes a first comparator having a first input for receiving the indication signal and a second input for receiving a first reference voltage. The first comparator produces a first comparison signal having a first state when said first reference voltage is greater than the indication signal and a second state when the first reference voltage is less than said indication signal. A second comparator is also provided and has a first input for receiving the indication signal and a second input for receiving a second reference voltage which is different from the first reference voltage.