Allen-Bradley 1771-ASB PLC-5 Remote I/O Adapter

Allen-Bradley 1771-ASB Remote I/O Adapter Module is a PLC-5 era interface that installs in a 1771 Universal I/O chassis and serves as a slave on the Remote I/O (RIO) network to connect remote I/O racks to a PLC-5 processor. As part of the 1771 I/O family, it translates the PLC-5’s control instructions into Remote I/O transactions that read inputs and write outputs across distributed modules mounted in 1771 racks, enabling a scalable, distributed control architecture. The 1771-ASB is designed for installation in Allen-Bradley Universal I/O chassis, including models such as 1771-A1B, 1771-A2B, 1771-A3B, and 1771-A4B, facilitating retrofits and expansion within existing PLC-5 installations. In typical use, the adapter provides the interface between the PLC-5 controller and multiple remote I/O modules, consolidating wiring and enabling centralized configuration of inputs and outputs across remote racks while preserving PLC-5 addressing and workflow. Catalog number 1771-ASB identifies this Remote I/O Adapter Module in Rockwell Automation’s 1771 I/O family, reflecting its role in distributed control for legacy PLC-5 systems.