Allen-Bradley 1791-24AR Block I/O Module 24 Inputs 8 Relay Outputs

Product Overview

The Allen-Bradley 1791-24AR is a Block I/O module from the Rockwell Automation 1791 series. It combines 24 AC inputs and 8 relay outputs in a single compact unit, reducing wiring and panel space. This module is designed for discrete control applications where cost and simplicity are key. By integrating input and output functions, it lowers total installation cost compared to separate modules.

Technical Specifications Breakdown

Key parameters for the 1791-24AR are listed below for quick reference:

Industry Applications

Its 24 inputs handle limit switches and sensors, while the 8 relay outputs control motors, solenoids, and indicators. The 120V AC operation matches common industrial line voltages, avoiding extra conversion costs. Using a single block I/O unit reduces spare parts inventory and simplifies troubleshooting, directly improving operational ROI.

Installation & Setup Guidance

Mount the 1791-24AR securely in a dry, ventilated enclosure. Connect external power between 85-132V AC to the module terminals. Wire each input to a 79-132V AC source; the input on-state current is 12.3mA at 132V. For outputs, ensure the load current does not exceed 1A resistive at 20-132V AC. Use twisted-pair wiring for noisy environments. Always verify polarity for DC loads when using the relay outputs.

Maintenance & Reliability

Inspect the module periodically for dust, moisture, and loose connections. The electromechanical relays have a finite life; monitor switching cycles in high-speed applications. Keep ambient temperature within the module's unspecified range (refer to manufacturer documentation). Regular cleaning of the enclosure vents prevents overheating and extends service life.

Compatibility & Integration

The 1791-24AR integrates with Allen-Bradley PLCs via the 1791 Block I/O backplane. It communicates using the remote I/O protocol, compatible with SLC 500, PLC-5, and ControlLogix systems. No special adapters are needed for basic operation. Check your controller's manual for configuration details.

Selection Guide & Purchasing Advice

When selecting the 1791-24AR, confirm your system's voltage and I/O count match the 24 inputs and 8 relay outputs. For applications requiring more outputs, consider pairing with additional 1791 modules. AutoDCSTech stocks this module and can advise on lifecycle status. Please verify current lifecycle status and availability with AutoDCSTech before ordering.