The Siemens 3SK2941-2AA10 is a SIRIUS safety relay packaged as a basic starter kit — it includes the 3SK2112-2AA10 basic unit, SIRIUS Safety ES Standard configuration software, and a 3UF7941-0AA00-0 USB PC cable, so you can commission the safety logic without hunting for separate programming tools. Rated for 24 VDC control voltage, it is a 2-channel safety relay with monitored start-up and valve monitoring capability — meaning it can supervise both the safety circuit and the downstream pneumatic valve state in a single device, which saves a module slot in the panel. The enclosure is IP20, so it belongs inside a control cabinet, not on the machine frame.
Width is 22.5 mm, depth 124.5 mm, height 100 mm — a single 22.5 mm module pitch on the DIN rail, so it fits in a tight row alongside contactors or terminal blocks without crowding the wiring duct. Input delay is adjustable from 0 to 150 ms — set it short for fast-reacting light curtains or longer to debounce a mechanical guard door switch and avoid nuisance trips. Total current draw is 6.5 A maximum — that is the sum of the relay coil and any load it switches through the safety outputs. Budget that into your 24 VDC supply sizing. PROFIBUS DP and PROFINET IO are supported when the appropriate interface module is added, with 64-bit cyclic data — so this base unit can become a networked safety node without replacing the core relay. Shock resistance is 15g / 11 ms, so it survives the vibration and impact of a machine cycle or a forklift bump to the panel door.