SIMATIC F-DI BaseUnit — one channel, push-in wiring
The 3RK1908-0AP00-0FP0 is a SIMATIC BaseUnit designed to host a fail-safe digital input (F-DI) module without integrated infeed — it supplies the module from the backplane bus, not a separate power terminal. It carries a single digital input channel with Type 1 characteristic per EN 61131-2, accepting 24 VDC nominal (20.4 to 28.8 V permissible range) with signal thresholds of 15–30 V for logic 1 and 0–5 V for logic 0. The terminal type matches both main current and auxiliary/control circuits.
Panel fit and environmental envelope
Mounting can be vertical or horizontal; allow 50 mm clearance above and below for airflow and wiring access. Vibration resistance is 15 mm at 6 Hz and 2 g up to 500 Hz; shock rated at 6 g for 11 ms — suitable for machine-mounted cabinets near rotating equipment. Pollution degree 2 (non-conductive, occasional condensation) and relative humidity 10–95 % non-condensing. The insulation voltage is rated 500 V between main and auxiliary circuits.
Sourcing and compliance posture
The substance prohibitance date of 15.04.2016 aligns with RoHS exemption phase-out timelines. No direct functional second-source exists from Siemens for this specific F-DI BaseUnit variant — the listed peer MPNs (6ES7513-1AL01-0AB0, 6ES7511-1AK02-0AB0, 6ES7511-1AL03-0AB0) are CPU modules in the S7-1500 family, not BaseUnits, and do not drop into the same panel position without a full backplane redesign.