Allen-Bradley 1791-24BR Block I/O Module: Mixed Input/Output for Industrial Automation

Product Introduction

As industrial automation evolved from centralized control to distributed architectures, the need for compact, self-contained remote I/O modules became critical. The Allen-Bradley 1791-24BR block I/O module from Rockwell Automation meets this demand by combining 24 DC inputs and 8 DC relay outputs in a single, DIN-rail-mountable unit. Designed for the 1791 Block I/O series, this module operates at 10 to 30 Volts DC and provides reliable signal conditioning and communication with compatible controllers.

Technical Specifications Breakdown

The 1791-24BR features an input on-state voltage range of 10-30V DC, ensuring compatibility with standard 24V DC sensors and switches. Its output voltage range spans 20-132V AC at 1A resistive maximum, allowing direct control of AC loads such as relays and small motors. External power requirements are 19.2-30V DC, supporting stable operation in industrial environments. The module’s 24 inputs are grouped into three groups of eight, simplifying wiring and diagnostics.

Industry Applications

In manufacturing plants, the 1791-24BR excels in remote I/O applications where space is limited. For example, on a packaging line, it can monitor 24 proximity sensors and control 8 pneumatic valves, reducing cabinet size and wiring costs. In material handling systems, the module’s mixed I/O capability streamlines connections between sensors and actuators, improving system reliability. Its compact form factor (6.95 x 4.35 x 3.85 inches) makes it ideal for distributed control panels.

Installation & Setup Guidance

Mount the 1791-24BR vertically on a DIN rail for optimal cooling and accessibility. Connect the remote I/O link via the terminal strips on the left and right sides. Use the two switch assemblies to configure the I/O rack number, communication rate, starting I/O group, last state, and last chassis. Ensure external power is within 19.2-30V DC before powering the module. Status indicators on the front panel help verify communication and I/O states during commissioning.

Compatibility & Integration

The 1791-24BR works with PLC-2, PLC-3, PLC-5/250, PLC-5 family, and SLC 5/02 modular controllers. It integrates seamlessly into existing 1791 Block I/O networks, providing a self-contained solution with its own power supply and signal conditioning. For replacement or upgrade projects, verify compatibility with your controller’s remote I/O scanner module.

Selection Guide & Purchasing Advice

Before ordering the 1791-24BR, confirm your system’s voltage requirements and I/O count. This module suits applications needing 24 DC inputs and 8 relay outputs in a single unit. For complete technical specifications, please contact BluePLC Industrial. Our team can verify lifecycle status and suggest alternatives if needed.