Allen-Bradley 1746-NO4I SLC 500 Output Module

The Allen-Bradley 1746-NO4I is a four-channel analog output module for the SLC 500 PLC family that provides independent 4–20 mA control signals from each channel to field devices. Designed for use in a fixed SLC 500 chassis, it requires an external 24 V DC power source to drive the current loops, drawing about 195 mA from the 24 V supply during operation. Each channel can drive a current loop to actuators, valves, transducers, or meters, enabling precise analog control for processes such as valve positioning, flow or pressure control, and instrumentation feedback. The NO4I is an open-chassis, backplane-mounted module (catalog number 1746-NO4I) that integrates with other SLC 500 I/O modules in a single rack, sharing common 0 V and 24 V power for the current loops. Utilizing Rockwell Automation’s SLC 500 ecosystem, it supports standard 4–20 mA signaling and is configured and diagnosed within the same software environment as other Allen-Bradley I/O modules, ensuring straightforward integration into existing control schemes. This module is suited for applications requiring reliable current-based signaling to control analog devices while coexisting with digital I/O in a unified Allen-Bradley SLC 500 system, offering a compact solution for expanding analog control in legacy automation architectures.