Product Overview

The Allen-Bradley 1746-IB8​ is a classic, 8-channel, 24V DC sinking digital input module, a fundamental building block for the widely deployed Allen-Bradley SLC 500 programmable logic controller (PLC) system. This module serves as a primary interface between the physical world of field devices and the logical world of the PLC’s processor. It is designed to reliably read the on/off status of industrial sensors and switches—such as push buttons, limit switches, proximity sensors, and photoelectric eyes—converting their 24V DC signals into a logic-level format that the SLC 500 processor can interpret within its control program. The 1746-IB8​ is categorized as a “sinking” input module, meaning that to activate an input, the connected field device must source 24V DC current intothe module’s input point, a common and robust wiring configuration in industrial control panels. This module represents a workhorse component of countless automation systems installed over several decades, providing dependable, noise-immune signal acquisition for discrete control applications.As part of the 1746 modular I/O family, the Allen-Bradley 1746-IB8​ is designed to be installed in a 1746 I/O chassis, which houses the SLC 500 processor, power supply, and other I/O modules. Its value lies in its simplicity, proven reliability, and ease of integration. Each of the eight optically isolated input channels provides a clear status indication via an LED, allowing for quick visual diagnostics. The module plays a critical role in machine and process control by feeding real-time data about the state of the manufacturing floor—whether a part is present, a door is closed, or a cycle is complete—to the central controller. For facilities operating and maintaining SLC 500-based systems, the 1746-IB8​ remains an essential spare part for repairs, system expansions, and legacy machine support, ensuring the continued operation of vital industrial infrastructure.

Technical Specifications