Allen-Bradley 871C-P4R12 Inductive Proximity Switch

The Allen-Bradley 871C-P4R12 is a compact inductive proximity switch from the 871C family, designed for non-contact detection of metal targets in tight spaces. It is a DC-powered sensor rated for 10–30 V DC and drawing up to 150 mA, with a normally open, PNP sourcing output (unshielded). The 871C-P4R12 features an 18 mm-diameter tubular housing and a nominal sensing distance around 4 mm for this variant. 871C sensors are designed for rugged environments and, in many examples, carry IP67 protection for ingress and dust resistance. The device is a tiny tubular sensor well suited for mounting in confined spaces on conveyors, tooling, and automation equipment where full-size sensors won't fit. Common applications include presence sensing and position detection on conveyors, small robotics, and other machinery requiring compact metal-detection in tight spaces. The Ser. B variant of this model is specifically noted for a 4 mm sensing distance.