What this adapter does on the line
The Siemens 3SF5402-1AB03 is an AS-Interface F-adapter that sits between an emergency-stop mushroom-type actuator and the AS-i bus. It translates the E-stop pushbutton into two safe digital inputs on the network and provides one output for the LED status indicator in the actuator head. The screw-type terminals accept field wiring directly; no intermediate junction box needed.
Rated Safety-Related 2, which means the adapter is designed for use in safety circuits up to SIL 2 / PL d per IEC 61508 / EN ISO 13849-1 when paired with a suitable safety monitor on the AS-i bus. The two digital inputs are intended for the dual-channel E-stop circuit; the single output drives the LED in the mushroom head to confirm the actuator state. This is a guarding component, not a standalone safety relay — the AS-i safety monitor handles the logic evaluation.
Front mounting only — the adapter fastens to the panel cutout behind the 3SB3 mushroom actuator, not to DIN rail. Dimensions are 52 mm deep, 30 mm wide, 61 mm tall. IP20 means it lives inside the enclosure; the actuator itself carries the higher IP rating at the panel face. The screw terminals handle 0.2–2.5 mm² solid or stranded, same as the 3SB3 contact blocks.