Allen-Bradley 1771-AL I DC Adapter Module

The Allen-Bradley 1771-AL I DC Adapter Module is a PLC-2 local I/O adapter that connects a 1771 I/O rack to the PLC-2 backplane, enabling direct communication between the processor and 1771 I/O modules in a Local I/O configuration. It is powered from the 1771 I/O power supply, with a backplane current draw of 0.7 A at 5 V DC, ensuring stable operation within standard PLC-2 installations. As part of the 1771 I/O family, this adapter provides the interface necessary for PLC-2 systems to expand I/O using 1771 modules, including both digital and analog devices designed for the 1771 bus. The 1771-AL I DC variant is specifically an adapter module used in legacy Allen-Bradley PLC-2 hardware to enable local I/O expansion and modular control architecture. Typically installed in a PLC-2 Local I/O chassis, it serves as the bridge between the controller and 1771 I/O modules, supporting applications in manufacturing and process control that rely on 1771 I/O compatibility.