Allen-Bradley 1746-IO4 SLC 500 Digital I/O Combination Module

June 23, 2026 • 2 min read • wayne • Industry News

Product Summary

The Allen-Bradley 1746-IO4 SLC 500 module combines two inputs and two outputs in one unit. This design saves valuable chassis space for your control system. It operates reliably on 120 Volts AC power for industrial applications.

Expert Technical Evaluation & Performance Review

The 1746-IO4 module delivers a signal delay between 35 and 45 milliseconds. This timing ensures predictable and stable I/O performance for your machinery. Each output channel handles up to 1.5 amps at 120 Volts AC. The module also supports outputs from 5 to 265 Volts AC. It works with DC voltages from 5 to 125 Volts DC. This wide range offers great wiring flexibility for diverse field devices.

The module draws only 25-30 milliamps from the backplane. This low power consumption reduces the strain on your SLC 500 power supply. Each input channel dissipates just 0.27 Watts during normal operation. Engineers will appreciate the module’s robust environmental tolerances. It operates safely in temperatures from -25 to 60 degrees Celsius. The unit withstands non-operating temperatures from -40 to 85 degrees Celsius. It also handles relative humidity from 5% to 95% without condensation. The module resists vibration up to 0.015 inches at 5 to 57 Hertz. It can endure an operating shock of 10 g. These ratings make the 1746-IO4 ideal for harsh factory floors.

Procurement & Buyer Guide

The 1746-IO4 is a digital combination module from the proven SLC 500 series. It features two inputs arranged in one common group. It also has two outputs arranged in one common group. The inputs accept 85 to 132 Volts AC at 47 to 63 Hertz. The relay outputs provide a continuous current rating of 4 amps. This module uses a self-lifting terminal plate that accepts two 14 AWG cables. This design simplifies field wiring and reduces installation time. Front panel LED indicators show the status of each input point. The status light activates when the correct input signal is present.

Procurement managers should note the separate power routing requirement. You must route input power separately from the cable to the I/O device. This separation ensures clean signal integrity and prevents noise issues. The 1746-IO4 is a cost-effective solution for applications needing a small mix of I/O points. It replaces the need for separate input and output modules in many cases.