The Siemens 3RQ4118-2AM00 is an output coupler from the SIRIUS 3RQ4 family of narrow-design coupling relays. The thermal current rating is 6 A, and the housing width is 6.2 mm, which means it fits tightly on a DIN rail inside a control panel where space is at a premium — you can pack several of these side-by-side without losing rail real estate. The single change-over contact gives you both a normally-open and normally-closed pole from one relay, handy for switching a load and sending a feedback signal back to the controller on the same channel. That speeds up panel wiring and eliminates screw-terminal torque checks during commissioning.
RoHS compliance is confirmed effective 26 September 2024, and REACH Article 33 information is available for the current candidate list.
The narrow profile means you can fit roughly 16 units per 100 mm of rail, which matters when you're laying out a dense control panel with dozens of interposing relays between the PLC and field devices. The plug-in relay design means the base stays wired to the panel; the relay itself can be pulled out for replacement without disturbing the wiring. That's a time-saver during troubleshooting or when a coil fails — just swap the relay cartridge, not the whole terminal block.