Standard OMNI-BEAM ac power blocks are available for either 120V ac or 220/240V ac. They provide the regulated low-voltage dc power required to run the circuitry of the sensor head and logic module (if one is used). All models, except emitter-only types, have two solid state output circuits, one for switching the load and the other for the alarm of the D.A.T.A. self diagnostic system. The LOAD output is an isolated 1/2-amp rated infinite-life solid-state relay. The alarm output is also a solid-state relay, rated at 0.2 amps, with one side of the contact tied internally to the "hot" side of the ac supply voltage. Both outputs have very low off-state leakage current for direct interfacing to programmable logic controllers (PLCs).