The Siemens 3RQ4118-1AF00 is an output coupler from the SIRIUS 3RQ4 family, designed as a narrow-format coupling relay with a plug-in relay base. It switches one change-over contact at 230 V AC/DC coil voltage, rated for a thermal current of 6 A. The 6.2 mm width makes it a space-saving fit for dense DIN-rail terminal blocks or control panels where every millimeter counts.
The 6 A thermal current rating (Ith) is the continuous current the contact can carry in free air at rated temperature — it's the limit for resistive loads like indicator lamps or small solenoid valves. The 230 V AC/DC coil means it accepts either supply type, simplifying panel wiring where AC and DC circuits mix. The single change-over contact gives you one normally-open and one normally-closed set in a common terminal layout, typical for signal-level switching or pilot-duty control circuits.
Deployment context
Snap-on DIN-rail mounting (6.2 mm wide) fits into standard 35 mm rail enclosures. The plug-in relay design means the relay base stays wired while the relay itself can be swapped without disturbing the field wiring, a practical feature during commissioning or fault isolation.