Allen-Bradley 871R-D12NP39-E2 Inductive Ring Sensor

The Allen‑Bradley 871R‑D12NP39‑E2 is a 12 mm ring‑style inductive proximity sensor (three‑wire, DC) with a 10–30 V DC supply and a normally open (PNP sourcing) output. It uses a 2 m, 3‑conductor PVC cable (Brown = +V, Black = Output, Blue = 0 V) and features a 12 mm ring diameter with a 2.5 mm minimum ball size for target detection. The device is rated for a maximum load current of 200 mA, with a voltage drop up to 2.4 V and leakage current under 10 μA. Protection includes reverse polarity, transient noise, short circuit, overload, and false pulse resistance, and the enclosure is IP67‑rated (NEMA 4 compatible) for harsh environments. Operating temperature ranges from –25 °C to +70 °C, with industrial‑level shock and vibration specs. Typical applications cited by Rockwell Automation include presence detection and object counting or wire‑gauge measurement—useful for metal parts detection as objects pass through the ring in automated lines.