Safety System for Hazard Zones
The Siemens SIRIUS 3RK3211-2AA10 is a modular safety system with 8 safety-related inputs, designed to evaluate emergency stop, protective door monitoring, enabling switches, selector switches, and two-hand operator panels. It is rated SIL 3 per IEC 61508 and IEC 62061, Category 4 per EN 954-1 and EN ISO 13849-1, and Performance Level e per ISO 13849-1 — the highest safety integrity levels for guarding applications. The 24 V DC control supply powers the evaluation logic and the spring-loaded terminal connections accept 0.2–2.5 mm² conductors.
What the Safety Ratings Mean for Fit
SIL 3 (IEC 61508) and PL e (ISO 13849-1) mean this module is designed for safety functions where a failure could cause serious injury — the architecture includes redundancy and self-diagnostics to achieve a probability of dangerous failure per hour below 10⁻⁷. Category 4 (EN 954-1 / EN ISO 13849-1) confirms the single fault tolerance and continuous monitoring. The 8 safety-related inputs can be configured as single-channel or two-channel, but the module does not have dedicated 2-channel inputs — it evaluates the input pairs through the logic. The 4/8 F-DI designation means 4 fail-safe digital inputs are available, expandable to 8 with the internal evaluation. The EMERGENCY OFF function is integrated, so no separate emergency stop relay is needed in the safety circuit.
The 22.5 mm width and 124 mm depth fit a standard single-module DIN-rail footprint — no special backplate or adapter required. Vibration resistance per IEC 60068-2-6 at 5–500 Hz, 0.75 mm amplitude, and shock resistance of 15 g for 11 ms cover most machine-mounted applications.