Allen-Bradley 1771-ASB Remote IO Adapter Module

The Allen-Bradley 1771-ASB Remote I/O Adapter Module is a Universal I/O interface that plugs into a PLC-5 system’s Universal I/O chassis and acts as a slave on the 1771 Remote I/O network, bridging the controller with remote I/O racks containing field devices. As part of the ASB family (Series E), it enables bidirectional data exchange between the PLC-5 processor and distributed I/O modules located in remote racks, supporting the standard Remote I/O addressing and scan cycles used in Allen-Bradley PLC-5 systems. It is designed for legacy PLC-5/SLC Remote I/O configurations and is commonly deployed to expand I/O across plant floors where a dedicated Remote I/O backbone is required. Note that Rockwell Automation discontinued the 1771 Remote I/O adapter modules, including the 1771-ASB, effective December 31, 2017, and replacement or migration paths to newer I/O architectures are recommended for ongoing projects.