Allen-Bradley 1769-PA4 Compact IO Expansion Power Supply

The Allen-Bradley 1769-PA4 Compact I/O Expansion Power Supply provides dual rails to power 1769 Compact I/O modules from a single AC source. It delivers 5 VDC at up to 4 A and 24 VDC at up to 2 A, enabling both logic circuitry and field devices to be powered from the same supply within a CompactLogix rack. The unit accepts a selectable 120/240 VAC input, catering to different regional power standards, and is documented to support up to 16 I/O modules across the rack (eight modules on each side of the supply). The 1769-PA4 (and the PA4K variant) is part of Rockwell Automation’s Compact I/O power-supply family and is specified in official technical data as providing 4 A at 5 VDC and 2 A at 24 VDC. With its dual-rail configuration, it can support a mix of digital, analog, and specialty expansion modules typical of 1769 Compact I/O systems, making it suitable for compact automation cabinets or retrofit projects where space and centralized power delivery are essential. The product is commonly selected for legacy 1769-based installations and newer systems that still rely on the 1769 Compact I/O ecosystem, offering a compact, single-unit solution to backplane power needs for backplane-connected I/O modules.