The Siemens 3SF5874-4EJ is an AS-Interface front panel module designed for control panels where you need local I/O points without running individual sensor cables back to the PLC. It carries one AS-i slave with four inputs and four outputs (4I/4O), all routed through a single two-wire AS-i bus cable, which simplifies field wiring and reduces termination points inside the enclosure. Rated IP65, the module is suited for environments where occasional washdown or dust ingress is a concern — think food packaging lines, washdown zones, or outdoor cabinets where condensation is routine. The plastic enclosure and 22 mm round mounting opening match standard panel cutouts for pilot devices, so it drops into existing pushbutton/indicator holes without extra machining. Its 54.5 mm depth leaves room behind the panel for the AS-i cable and insulation-displacement terminals, while the 200 mm height and 45 mm width keep the footprint tight on a crowded subplate.
Wiring & integration
Connection is via insulation-displacement terminals (IDC) — strip the AS-i flat cable, press it into the slot, and the contact cuts through the jacket automatically. No screw terminals, no ferrule crimping. The module can be mounted vertically or horizontally, depending on panel layout. Operating temperature range is -25 to +70 °C; storage range extends to -40 to +80 °C. The module ships with two labels (black) for marking the four command points. The wedge-base socket design and the four lampholders indicate this module is built to accommodate illuminated pushbuttons or pilot lights — the light source is optional and field-installable. No positive opening contacts and no emergency stop function, so it's for standard signaling and control, not safety-rated stop circuits.