An optoelectronic safety device for monitoring a machine movement includes a detection device and a control device. The detection device includes a transmitter unit which transmits an optical signal having a sequence of signal pulses, each of which has a different pulse intensity, and a receiver unit which receives the optical signal. The control device includes an evaluation unit which evaluates the optical signal received by the receiver unit, a pulse selection index, and a pulse selection unit which changes the pulse selection index if the pulse intensity of one of the signal pulses is outside of an optimal intensity range. The control device enables the machine movement if an intensity of a received signal is within a permissible intensity range, and outputs a trigger pulse to stop the machine movement if the intensity of the received signal is outside of the permissible intensity range.