The S18 series threaded barrel Sensor that features EZ-BEAM® technology, with specially designed optics and electronics for reliable sensing without adjustments. The device is completely epoxy-encapsulated to provide superior durability, even in harsh sensing environments. Includes advanced diagnostics to warn of marginal sensing conditions or output overload (DC models). The Dark Operate (DO) output may be wired as a normally open marginal signal alarm output, depending upon hookup to the power supply. The device is protected against false pulse on power-up and continuous overload or short circuit of outputs.