Abstract: The invention is directed to a safety device for a machine that includes a first transceiver unit for emitting a first light beam in a first time slot and for receiving a second light beam. The safety device includes a second transceiver unit arranged for emitting the second light beam in a second time slot that is different from the first one. The safety device also includes an evaluation unit for determining a reflecting object between the first transceiver unit and the second transceiver unit, only if the first light beam is received by the first transceiver unit in the first time slot or the second light beam is received by the second transceiver unit in the second time slot. Additionally, a non-reflecting object may be detected, if by neither of the two transceiver units in both time slots one of the two light beams is received.

Abstract: Production and work machines are to be able to be more safely operated. Thereto, they can be equipped with a safety device, which comprises a light curtain, a first and a second reflection device, which are each formed for reflecting light of the light curtain, and a first identification element integrated in the first reflection device as well as a second identification element integrated in the second reflection device. Moreover, the safety device comprises a first sensor device and a second sensor device for reading out the identification elements. A control device provides a start signal for the machine only if the first sensor device reads out the first identification information and the second sensor device reads out the second identification information at the same time.

Abstract: The invention is directed to a safety device for a machine that includes a first transceiver unit for emitting a first light beam in a first time slot and for receiving a second light beam. The safety device includes a second transceiver unit arranged for emitting the second light beam in a second time slot that is different from the first one. The safety device also includes an evaluation unit for determining a reflecting object between the first transceiver unit and the second transceiver unit, only if the first light beam is received by the first transceiver unit in the first time slot or the second light beam is received by the second transceiver unit in the second time slot. Additionally, a non-reflecting object may be detected, if by neither of the two transceiver units in both time slots one of the two light beams is received.