Allen-Bradley 1771-IND SLC 500 Digital Input Module

The Allen-Bradley 1771-IND is a 16-channel digital input module for the PLC-5/SLC-500 backplane that brings 24V AC sensor signals into the controller. This module plugs into a standard 1771 I/O rack and maps its 16 inputs to the PLC’s input image, enabling straightforward wiring of pushbuttons, limit switches, and other field devices. Each channel accepts a 24V AC digital input and reports a reliable boolean to the processor for fast state monitoring. As part of Rockwell’s 1771 I/O family, the 1771-IND is designed to work with typical PLC-5 and SLC-500 workflows, commonly used in manufacturing lines and automated machinery. The 16 discrete input points support scalable wiring for multi-sensor configurations, and the module is designed to operate with the backplane architecture and configuration tools used for PLC-5-based systems. When paired with compatible output modules and logic processors, the 1771-IND enables synchronized control logic, ladder diagrams, and sequencing across an automation cell. A compact, plug-in solution for expanding digital input capacity, the 1771-IND helps teams monitor external conditions—interlocks, sensors, and other discrete signals—without redesigning existing control architectures.