Siemens 3RH2140-1BB40 Sirius auxiliary contactor relay is a compact auxiliary switching block that provides four normally open contacts driven by a 24 V DC coil, all in a size S00 package with screw terminals. This configuration lets it serve as a signaling or interlock element between PLC outputs and load-controlling contactors in automation circuits. Typical applications include expanding the auxiliary contact capability in control panels, feeding logic circuits, or interlocking sequences in industrial equipment.
