SIRIUS MSS Extension Module — 8 DO, 24 V DC
The Siemens 3RK3311-2AA10 is an extension output module in the SIRIUS Modular Safety System (MSS) family, delivering eight non-safety-related digital outputs at 24 V DC, 0.5 A each. It snaps onto a DIN rail (22.5 mm wide, 124 mm deep) and connects via spring-loaded terminals — no screwdriver needed for the power or signal wiring. The 24 V DC control supply is the only voltage it needs; the module is parameterizable through the MSS ES engineering software, so you can map each output's behavior (e.g., delayed off, pulsed signaling) without adding hardware.
This module lives downstream of a safety-capable MSS CPU (3RK31xx). It handles the non-safety output loads — indicator lamps, solenoids, contactor coils that don't need a SIL-rated path — freeing the safety-rated output modules for the guarded zone.
Environmental and EMC Robustness
Rated for industrial environments: shock tested to 15 g / 11 ms, vibration per IEC 60068-2-6 at 5–500 Hz / 0.75 mm, and EMC immunity includes 2 kV burst on power ports (IEC 61000-4-4) and 4 kV contact / 8 kV air electrostatic discharge (IEC 61000-4-2). Pollution degree 3 covers conductive dust and humidity up to 95 % RH. The finger-safe touch protection (IP20) means an operator can't accidentally contact live terminals through the front.