What it is and where it goes
The Siemens 3SF5874-4EB is an AS-Interface front panel module — a slave with four inputs and four outputs (4I/4O) that mounts in a standard 22 mm round panel cutout. It's built for control stations where you need illuminated pushbuttons and status lamps tied directly to the AS-i bus, no separate I/O block. The IP65 rating means it handles washdown and dust on the panel face, so it's a fit for food, beverage, or any wet-area line where you don't want a separate enclosure.
Key ratings and what they mean for fit
The module is rated at 30 V DC (the AS-i bus voltage) and carries positive-opening contacts — that's the mechanical guarantee that the NC contact opens even if the spring breaks, which matters for safety circuits where you need a reliable off-state. The four lamp holders use a wedge-base socket design, so bulb swaps are tool-less. The front ring is included, and the actuator elements are clear illuminated pushbuttons, four of them, with black labels. The housing is rectangular plastic, fastened vertically or horizontally, and the slave type is 4I/4O — four inputs for pushbuttons or limit switches, four outputs for indicator lamps or small solenoids.
Physical dimensions and mounting
The module measures 200 mm tall, 45 mm wide, and 54.5 mm deep — that's the depth behind the panel. The 22 mm mounting diameter is the standard hole size for European pushbutton stations. The enclosure mounts vertically or horizontally, and the rectangular front shape gives you four illuminated pushbuttons in a single cutout. No backing plate needed. Operating temperature range is -25 to +70 °C; storage range is -40 to +80 °C, so it's fine for unheated plant floors or outdoor cabinets in moderate climates.