Allen-Bradley 1771-P7 Power Supply For PLC-5 I Chassis

Allen-Bradley 1771-P7 Power Supply for PLC-5 I/O Chassis is a standalone AC-input module that supplies the 5 V DC backplane power used by a single 1771 I/O chassis in PLC-5 systems. It accepts 120 or 220/240 VAC input, enabling operation across common North American and international mains. The P7 is designed to power one 1771-A1B, -A2B, -A3B, -A3B1, or -A4B I/O chassis when paired with an appropriate adapter module or PLC-5 processor that does not include an internal power supply. It sits within the PLC-5 I/O topology as a dedicated power source for backplanes and is referenced in Rockwell/Allen-Bradley installation and user literature for 1771 I/O configurations. Rockwell Automation has discontinued the 1771-P7 power supply as of March 31, 2021, reflecting its status as a legacy component. The device remains relevant for maintaining or retrofitting older PLC-5 installations that rely on 1771 I/O racks, providing reliable, standalone 5 V DC backplane power to the I/O backplane.