Siemens 3RQ3018-2AB00 Relay Coupler 24V AC/DC Push-in 1CO 6A

The Siemens SIRIUS 3RQ3 series 3RQ3018-2AB00 is an ultra-slim coupling relay (output coupler) with a housing only 6.2 mm wide. It couples and electrically isolates signals between PLC or controller outputs and field loads, protecting the controller's output stage while passing the signal through. It provides one change-over contact (1 CO) with a 6 A thermal current rating, so it drives solenoid valves, contactor coils and similar loads directly. Protective separation between the control circuit and the auxiliary circuit is rated up to 300 V—no separate isolating amplifier is needed.

The defining feature of this model is its spring-loaded push-in terminals. Wiring requires no screwdriver: strip the conductor and push it in to complete the connection. This is markedly faster than screw terminals, and the spring mechanism maintains constant contact pressure even under vibration and temperature cycling—where screw terminals can gradually loosen. Conductors from 0.25 to 2.5 mm² are accepted (AWG 20-14), and finely stranded wire without end processing can be inserted directly. The 24 V AC/DC coil operates over a wide 0.8-1.25 × Us range to tolerate supply fluctuation, and a green LED on the front panel gives an immediate read on operating and fault status.

Total power consumption is only 0.3 W, the enclosure material carries a UL94 V-0 flammability rating, and the relay complies with the RoHS directive (2015-03-25). The 93 × 6.2 × 72.5 mm housing snaps onto any standard 35 mm DIN rail in any mounting position and requires 0 mm spacing for side-by-side mounting, so dozens can be packed onto a single rail. Mechanical service life reaches 10,000,000 operating cycles.