The Siemens 3RK3922-1AC10 is a SIRIUS modular safety system starter kit — the base building block for a configurable safety logic controller. It snap-mounts onto a DIN rail (or screws in with a push-in lug) and carries IP20 protection on both the enclosure and terminals, meaning it lives inside a control cabinet, not on the machine frame. Safety integrity is rated SIL CL 3 per IEC 61508 and performance level PL e per IEC 62061 — the highest single-fault-tolerant tier for machinery safety. That puts it in the same class as guarding circuits for presses, robots, and high-speed packaging lines where a single failure cannot lead to loss of the safety function. The kit supports up to 8 safety-related inputs, configurable as 2-channel or single-channel, with parameterizable input delay from 0 to 150 ms. It also handles valve monitoring, muting with two parallel sensors, and monitored start-up — covering the common safety functions (emergency stop, interlock, light curtain) without a separate safety PLC.
PROFIBUS DP and Parameterization
When paired with the DP interface module, the 3RK3922-1AC10 communicates over PROFIBUS DP with 64-bit cyclical data. Both inputs and outputs are parameterizable, so the safety logic and diagnostics can be tuned from the engineering station rather than hard-wired. The unit is rated for 24 V DC control voltage. Input delay is adjustable from 0 to 150 ms — useful for debouncing mechanical contacts or filtering out transient disturbances on the safety circuit.
Shock resistance is 15 g for 11 ms, and the degree of pollution is rated 3 (conductive pollution typical in industrial enclosures). Wiring accepts 2 x (20–14 AWG) solid or stranded conductors.