Safety relay output expansion for enabling circuits
The Siemens 3SK1213-1AB40 is a SIRIUS safety relay output expansion module designed for relay enabling circuits. It provides three safety-related instantaneous contacts, each rated at 10 A across 24 V, 115 V, and 230 V, making it suitable for switching safety loads at common control voltages without derating per the datasheet. This output expansion mounts on a horizontal standard DIN rail using screw and snap-on fastening, occupying 90 mm width, 100 mm height, and 121.6 mm depth. The screw-type terminals accept solid conductors: 1x (20...12 AWG) or 2x (20...14 AWG), and with ferruled stranded: 1x (0.5...2.5 mm²) or 2x (0.5...1.5 mm²). Rated control voltage is 24 V DC, with an operating range of 0.8...1.2 times rated (19.2...28.8 V). Typical response time is 20 ms, maximum 20 ms; DC dropout extends to 70 ms maximum. The module handles a total current maximum of 30 A across all contacts, with maximum power loss of 5.5 W.
Safety circuit integration and environmental ratings
Designed for safety-related circuits, the 3SK1213-1AB40 carries pollution degree 3 and overvoltage category 3 ratings, per IEC 60947-5-1 and IEC 61000 for EMC emitted interference. UL approval is confirmed, supporting panel builds destined for North American installations. Relative humidity tolerance is 10 to 95% during operation. Shock resistance is rated at 5 g for 10 ms. The module supports parametrizable delayed or undelayed switching (only with system connector), though the base variant ships with delayed switching set to 0 and safety-related delayed switching at 0. Minimum operational current is 5 mA at 17 V, ensuring reliable switching even with lightly loaded safety circuits. Maximum operating frequency is 360 1/h, adequate for most machine-guarding cycles without exceeding thermal limits.
For BOM-line commitments, the 10 A contact rating across multiple voltages and the 3 safety contacts are the fit-determining specs.