The Allen-Bradley 1771-PA is a stand-alone power supply module for PLC-5 1771 I/O backplanes, delivering the 5 V DC power that runs the backplane and connected I/O modules. It accepts 120 VAC input at 1 A or 220–240 VAC input at 0.5 A, enabling operation across common mains voltages. This supply provides the 5 V DC backplane power required by 1771-series I/O racks in PLC-5 systems, and is designed for use with 1771 controllers and their I/O modules.
