The 3SK1220-2AB40: The 24 V DC rated supply is the standard control voltage for this safety relay family — it powers the internal logic and sensor monitoring circuits. The push-in spring terminals accept solid or stranded wire from 20 to 16 AWG, and with ferrule processing from 0.5 to 1.0 mm², which matches typical control wiring practice for safety circuits.
Configurable safety functions
This module is parameterizable for multiple sensor configurations: floating or non-floating sensors, monitored or automatic start-up, 1-channel or 2-channel sensor connection, cross-circuit detection, startup testing, antivalent sensors, and 2-hand switches. This flexibility lets it adapt to different safety architectures — e.g., a light curtain with OSSD outputs or dual-channel emergency stop buttons — without hardware changes.
Environmental and mounting considerations
Relative humidity during operation can be 10 to 95 %.