Siemens 3SK1220-2AB40 Industrial Solid State Relay

Siemens 3SK1220-2AB40 is a SIRIUS safety relay input expansion that extends a compatible 3SK1 safety relay system with additional sensor inputs, enabling safer automation configurations. It supports an additional two-channel input or two independent 1-channel sensors and operates from a 24 V DC supply (Us = 24 V DC) with a spring-type (push-in) terminal for robust, tool-free wiring. This module carries 0 safety contacts of its own, so it does not switch power but feeds safety signals to the main safety relay. Part of the SIRIUS Input Expansions family, the 3SK1220-2AB40 is documented with RoHS compliance, WEEE and REACH information, and lists a net weight of 0.150 kg with packaging dimensions around 36 x 109 x 152 mm. The product is identified by EAN 4011209913875 and is designed to integrate into Siemens’ modular safety architecture for monitoring additional sensors in safety-related circuits, making it suitable as an expansion for applications requiring additional channel monitoring without adding standalone switching capability.