The 3RK4320-3LR51-0BA0 is a SIRIUS motor starter MCU designed for AS-Interface networks — it combines a direct starter, bimetal overload protection, and bus communication in one IP55 housing. The control supply is 20.4–26.4 V DC, so it runs on a standard 24 VDC control loop, and the AS-Interface protocol support lets you integrate it into a distributed I/O architecture without a separate fieldbus coupler.
Mounting and environmental fit for enclosure planning
Dimensions are 145 mm deep, 182 mm wide, and 220 mm high — check your sub-panel real estate before committing, especially the depth if the enclosure is shallow. IP55 means it's protected against dust ingress and water jets from any direction — suitable for standalone mounting in washdown areas or inside a sealed enclosure where condensation is a concern. Ambient operating range is -25 to +35 °C — if your panel sits near a heat source or in a hot climate, derate or ventilate to stay inside that envelope.