Overview
The Allen-Bradley 1791-32B0 is a CompactBlock discrete input module designed for high-density I/O applications in industrial control systems. This 32-point input module operates on 24VDC and integrates seamlessly into ControlLogix architectures, making it ideal for manufacturing lines, process automation, and machinery control requiring multiple discrete sensor inputs.
Key Features
- 32 Discrete Input Channels — Organized in 4 groups of 8, enabling efficient signal management and wiring organization.
- 24VDC Nominal Rating — Accepts 10–30VDC sensor inputs, supporting standard proximity switches, photoelectric sensors, and limit switches.
- Fast Response Time — Millisecond-level input response for real-time process feedback.
- ControlLogix Compatibility — Direct integration with Allen-Bradley ControlLogix platforms and block I/O networks.
- Field-Replaceable Design — Modular construction allows quick swaps without major system downtime.
- Compact Form Factor — Space-efficient mounting suitable for control enclosures and distributed I/O installations.
Technical Specifications
- Module Type: Discrete DC Input
- Input Channels: 32 points (4 groups of 8)
- Nominal Voltage: 24VDC
- Input Voltage Range: 19.2–30VDC
- Maximum Current: 300mA per module
- Off-State Leakage Current: 1.5mA minimum device requirement
- Weight: 1.81 lbs
- Configuration: CompactBlock discrete I/O
- Communication: RIO (Remote I/O) network capable
Typical Applications
The 1791-32B0 excels in:
- Assembly & Packaging Lines — Real-time monitoring of conveyor sensors, presence detectors, and proximity inputs.
- Process Control — Equipment status feedback from pumps, valves, motors, and instrumentation.
- Machine Control — Discrete signal acquisition for automated machining, pressing, and material handling systems.
- Industrial Automation — General manufacturing automation where multiple 24VDC sensor inputs require centralized I/O management.
Compatibility & Replacements
The 1791-32B0/B is a discrete block I/O module part of Allen-Bradley’s CompactBlock product family. While discontinued by the manufacturer since 2015, it remains fully functional in legacy ControlLogix systems and is widely stocked as replacement inventory. For modern implementations, Rockwell Automation offers updated CompactBlock modules and integrated I/O solutions; however, the 1791-32B0 continues to provide cost-effective upgrades for existing systems without firmware or platform changes. Engineers should verify off-state leakage current specifications of connected devices to ensure compatibility with the module’s 1.5mA minimum requirement.
