8-channel 24 V DC sink input — temperature-rated for cabinet extremes
The 6AG1221-1BF32-4XB0: Eight digital inputs, each sinking 2.5 mA minimum at 15 V DC for a logic '1', with the supply rail permitted to sag to 20.4 V DC before the channel drops out. Rated for the full eight inputs simultaneously up to 50 °C ambient — no derating required within that envelope — and the plastic IP20 housing fits a 45 mm wide DIN-rail footprint. The module draws 105 mA max from the backplane 5 V bus and 4 mA per channel from the load supply; total dissipation is 1.5 W typical, so thermal rise inside a dense cabinet stays manageable.
Wiring and diagnostics — parameterisable with per-channel status
All eight inputs are parameterisable, with diagnostic alarm and supply-voltage monitoring built in — the module reports a missing L+ before the PLC logic sees a false '0'. Unshielded cable runs up to 300 m and shielded runs up to 500 m are allowed; the module requires a front connector (sold separately) and includes a maintenance-friendly design for field swap-out.