Overview
The Allen-Bradley 871TM-B4N12-R3 is a tubular stainless steel inductive proximity sensor designed for robust detection of metallic objects in industrial automation and machine control environments. This metal face sensor combines proven 871TM family reliability with a compact 12mm barrel diameter and standardized Micro quick-disconnect connectivity for drop-in integration into existing control architectures.
Key Features
- Metal Face Design: Optimized for ferrous and non-ferrous metal detection without false triggers on non-metallic materials
- AC/DC Operation: 20–250V AC/DC input voltage, accommodating both legacy and modern power supplies
- 4mm Sensing Distance: Reliable, repeatable detection at a standard 4mm stand-off for precise positioning applications
- Normally Open (N.O.) Output: Switch closes when metal target enters sensing field; open in default state
- Stainless Steel Construction: 12mm tubular barrel with corrosion resistance for washdown and harsh environments
- Micro QD Connector: AC-rated Micro quick-disconnect for fast installation, removal, and field replacement
Technical Specifications
The sensor operates in 2-wire configuration with non-shielded sensing. Short circuit, overload, transient noise, false pulse, reverse polarity, and radio frequency interference protection are built-in. Housing material is stainless steel tubular with a 12mm bore diameter. Contacts are N.O. type with AC micro quick-disconnect coupling.
Typical Applications
- Metal part presence detection on conveyor lines and indexing systems
- Proximity switching in packaging, automotive assembly, and food processing machinery
- Position sensing for machine guards, door interlocks, and safety systems
- Industrial equipment control requiring washdown and chemical-resistant housings
- Integration with Allen-Bradley PLCs, drives, and I/O modules for networked automation
Compatibility & Replacements
The 871TM-B4N12-R3 belongs to the Bulletin 871TM family of tubular stainless steel sensors from Allen-Bradley (Rockwell Automation). Direct replacements within the 871TM line exist for different sensing distances (3mm, 4mm), contact types (N.O./N.C.), and connector options (Micro QD, Mini QD, PVC cable, ToughLink cable). Consult the 871TM product selector or your Rockwell distributor to verify mechanical and electrical compatibility before substitution. This sensor is compatible with standard DIN 43650 wiring and integrates seamlessly into control cabinets using legacy or modern automation platforms.
