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). Solid-state complementary (SPDT) DC switch, NPN (current sinking) or PNP (current sourcing) output configurations available depending on model. 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.