Product Overview

The ALLEN-BRADLEY 1746-IH16A is a high-voltage digital input module designed for the Allen-Bradley SLC 500 series of modular programmable controllers. This module provides a robust 16-channel interface, specifically configured for sinking input​ operation, capable of accepting a wide range of input voltages. A key distinguishing feature of the ALLEN-BRADLEY 1746-IH16A​ is its ability to accept both AC and DC input signals, with a nominal operating voltage of 120V. This dual compatibility makes it exceptionally versatile for directly interfacing with a broad array of industrial field devices without requiring intermediate interfacing components. Its primary function is to convert the on/off state of high-voltage field devices, such as limit switches, selector switches, pushbuttons, and proximity sensors, into a logic-level signal that the SLC 500 processor can read and process within its control program.Installed into an I/O slot of a compatible 1746 series chassis, such as the 1746-A13B, the ALLEN-BRADLEY 1746-IH16A​ forms a critical link between the high-power control circuit and the low-voltage logic of the PLC. Each of its 16 input points is designed to accept a sinking (NPN) signal; meaning the field device provides a path to common (sinks current) when active. The module itself sources a small sensing current. The wide voltage acceptance range (79-132V AC/DC) ensures reliable operation despite typical line voltage fluctuations. The ALLEN-BRADLEY 1746-IH16A​ is engineered for industrial durability, incorporating features like optical isolation between each input channel and the internal logic circuits. This isolation is critical for protecting the sensitive processor and other modules from voltage transients, noise, and potential ground loops present in the high-voltage field wiring. The deployment of the ALLEN-BRADLEY 1746-IH16A​ is a strategic choice for applications where devices operate directly on 120V control power, simplifying wiring diagrams by eliminating the need for separate 24V DC power supplies for sensors and allowing for direct monitoring of devices like motor contactor auxiliary contacts. It represents a reliable, high-density solution for consolidating high-voltage discrete signals into a centralized SLC 500 control system.

Technical Specifications