SINGLE-CHANNEL SAFETY OUTPUT

The present invention relates to a safety switching device for fail-safely switching on and off an electrical load, and to a system comprising at least two safety switching devices which interact in a fail-safe manner via a single-channel. The safety switching device comprises a fail-safe control unit; a first and a second electronic switching element; at least one input terminal for receiving a first switching signal that causes a switching of said switching elements, and a clocked output terminal (L11) for connecting said safety switching device to a second safety switching device (104). The clocked output terminal provides a clocked signal (108) depending on the first switching signal and being monitored by said control unit for performing a cross fault detection, wherein said clocked output terminal (L11) is further adapted to provide power to said second safety switching device (104), wherein said clocked signal (108) comprises a train of pulses indicative of a true safety status of the safety switching device, said clocked output terminal (L11) outputs a constant 0 V signal, if the safety status of the safety switching device indicates a fault, and wherein the clocked signal (108) differs from all other clocked signals present in the safety switching device.