ABB 1SNA645004R0400 Safety Relay Module 24VDC

ABB 1SNA645004R0400 (RB121-230VUC) is a DIN-rail mounted interface relay module with a single Form C (SPDT) contact and a coil rated for 230 V AC/DC. The device switches loads up to 6 A at up to 250 VAC, providing electrical isolation between control circuits and loads in automation cabinets. The coil is connected to A1 and A2, accepting 230 V AC or DC drive for direct integration with standard control supplies without a separate driver. As part of ABB’s RB121 family, this module is designed for compact, modular installation on 35 mm DIN rails and is commonly used to route signals to PLCs, implement interlocks, or interface sensors with higher‑level controllers in control panels. The 1SNA645004R0400 is catalogued as RB121-230VUC, ensuring compatibility with ABB interface-relay components and existing RB121 configurations in multi‑relay assemblies. Its robust design supports reliable operation in industrial environments where isolation and dependable switching of moderate loads are essential.