What this adapter does on the line
The Siemens 3SF5402-1AB04 is an AS-Interface F-adapter that sits between a panel-mounted EMERGENCY-STOP mushroom actuator and the AS-i safety bus. It brings two safety-related digital inputs and one standard output for LED indication back to the network. That means the E-stop pushbutton wiring terminates here, not at a remote safety PLC input card — the adapter handles the safety communication over the yellow AS-i flat cable. The two inputs are safety-rated (Safety-Related = 2 per the listing), so they can be wired as a dual-channel E-stop circuit meeting Category 3 / PL d per EN ISO 13849-1. The single output drives the actuator's integrated LED for status indication — lit when the motor is running, dark when stopped, or pulsed for a fault code, depending on how the AS-i master programs it. No screwdriver needed for the control wiring — strip to 8 mm, push in. The adapter itself is front-mounted through a 30 mm × 61 mm cutout in the enclosure door or panel, with a 52 mm depth behind the panel. That depth is tight: verify clearance to the backplane or DIN-rail components behind the mounting surface before cutting the hole.
RoHS compliance date is July 1, 2006, so the part is RoHS-compliant per the original EU directive.