Overview
The Allen-Bradley 1771-WHFB is a fused field wiring arm designed for the PLC-5 product family. It provides a critical interface between field wiring and 1771 series I/O modules, simplifying interconnections while maintaining signal integrity. This unit features 21 terminals with tin-plated contacts and integrated 1.5A fuse protection per output channel, delivering reliability in industrial control applications.
Key Features
- 21 tin-plated terminals for secure, corrosion-resistant connections
- 1.5A fuse per output for circuit protection and fault isolation
- Compatible with all 1771 series I/O modules (1771-A1B through 1771-A4B chassis)
- Field-rated conformal coating for moisture and chemical resistance
- Minimal external power requirement; operates passively
- Compact form factor suitable for dense control panel installations
Technical Specifications
Wire termination accommodates 14–20 AWG (2.5 mm² – 0.5 mm²) solid or stranded copper. Screw torque requirement is 9 lb-in (1.0 Nm). Terminal rating for inputs/outputs is typically 8A @ 250V for the common terminals. The unit measures approximately 8.265 inches height × 1.224 inches width × 2.0 inches depth. Operating temperature range is 0–60°C. All fuses are rated 1.5A–250V.
Typical Applications
- Discrete I/O interface between field sensors and PLC-5 controllers
- Process automation and machinery control systems
- Manufacturing plant wiring distribution and fusing
- Legacy industrial systems requiring PLC-5 module integration
- Emergency shutdown circuits and pilot-duty signal interconnection
Compatibility & Replacements
Compatible With
- Allen-Bradley 1771-A1B, 1771-A2B, 1771-A3B, 1771-A4B I/O chassis
- All PLC-5 discrete and analog I/O modules (1771-OBD, 1771-IFE, 1771-OFE, etc.)
- Field wiring rated 14–20 AWG copper with 120°C insulation
- PLC-5 software: RSLogix 5, Studio 5000 (legacy project support)
Replaces / Drop-In Replacement For
- Earlier versions of 1771-WHFB (all revisions: /A, /B, /C, /D, /F compatible)
- Functionally equivalent to 1771-WHF (non-fused variant) in form factor; verify fuse requirement before substitution
Works With
- PLC-5 family controllers and all 1771 bulletin I/O module sets
- Standard 24 VDC/120 VAC industrial control power supplies
- EtherNet/IP gateway modules for modern supervisory integration (via processor)
- RSLogix 5 programming and ladder logic environments
- Panel-mount DIN rail and free-standing cabinet configurations
