Introduction
Is your CompactLogix assembly struggling with unstable backplane power? The Allen-Bradley 1769-PA4 is a dedicated I/O power supply engineered to feed clean, reliable power to your 1769 Compact I/O modules. As part of the trusted CompactLogix product line from Rockwell Automation, this module delivers 4.0 A at 5V DC and 2.0 A at 24V DC, giving you the headroom to build dense, high-performance control systems without compromise.
Why the 1769-PA4 Belongs in Your Upgrade Plan
When you replace an aging power supply, downtime is the enemy. The 1769-PA4 simplifies your migration because it supports a switch-selectable input voltage range of 85…265V AC or 170…265V AC. That flexibility means one part number covers both 120V and 220V nominal installations. With an input frequency range of 47…63 Hz, it adapts to standard industrial power networks worldwide.
Power supply distance rating is a critical planning factor in any CompactLogix configuration. The 1769-PA4 allows up to 8 I/O modules on either side of the unit, for a maximum of 16 modules per power supply. This architecture lets you distribute power efficiently across your chassis and avoid the voltage drop issues that plague undersized supplies.
Technical Specifications That Matter
Let’s break down the numbers that directly affect your system design.
Current Capacity
The 1769-PA4 provides 4.0 A at 5V DC and 2.0 A at 24V DC. The 5V DC rail powers the backplane logic, while the 24V DC output supports modules requiring higher voltage. If your assembly includes a high count of discrete outputs and analog modules, this current budget is essential.
Input Power and Consumption
Power consumption is 200 VA at 120V AC and 240 VA at 240V AC. Maximum inrush current reaches 25 A at 132V AC. These figures help you size upstream breakers and wiring correctly.
Physical and Environmental
The module measures 118 x 70 x 87 mm (4.65 x 2.76 x 3.43 in.) and weighs 525 g (1.16 lb). It operates in relative humidity of 5 to 95% non-condensing and withstands 30 g shock and 5 g vibration at 10 to 500 Hz. Certifications include c-UL-us, CE, and C-Tick.
Applications Across Industries
Discrete Manufacturing
A packaging line running dozens of discrete outputs depends on stable 5V DC backplane power. The 1769-PA4’s 4.0 A capacity keeps every module responsive, reducing phantom faults that cost production minutes.
Process Control
Analog modules are sensitive to power ripple. By providing a dedicated 24V DC rail at 2.0 A, this supply isolates analog signal conditioning from the logic rail, improving measurement stability.
Infrastructure Retrofits
When upgrading an existing CompactLogix panel, the switch-selectable input range eliminates the need for a transformer swap. You simply set the switch for your site voltage and commission.
Installation and Setup
The 1769-PA4 supports DIN rail or panel mounting. Use 14 AWG (2.5 mm²) solid copper wire rated at 90 °C or greater with 1.2 mm insulation maximum. The terminal block includes a finger-safe cover. Before energizing, verify the input voltage selector switch matches your supply. An incorrect setting can damage the module. The unit features a bus lever with locking function, LED status indicator, and a replaceable fuse accessible behind the housing cover.
Maintenance and Reliability
The 1769-PA4 uses an internal fuse — Littelfuse 02153.15MXP or Wickmann 19195-3.15A. Inspect the LED status indicator periodically. In dirty environments, check that the open-style enclosure remains free of conductive dust. Power dissipation is 8 W at 60 °C, so ensure adequate panel ventilation. Following the manufacturer’s safety manual for all service procedures is essential.
Compatibility and Integration
This power supply is designed for the 1769 CompactLogix platform. It powers 1769-L3x processors, controllers, and I/O modules. Up to 16 modules can connect when distributed eight per side. The continuous isolation voltage is 265V from AC input to system, protecting your low-voltage logic from transients.
Selection Guide
Before ordering, confirm your total module count and current draw. Verify your input voltage and frequency. Check that your enclosure provides sufficient space for the 118 x 70 x 87 mm footprint. SpareTechPLC stocks the 1769-PA4 and can help you verify compatibility with your existing CompactLogix assembly.
Frequently Asked Questions
What is the current capacity of the 1769-PA4?
It provides 4.0 A at 5V DC and 2.0 A at 24V DC.
How many I/O modules can one 1769-PA4 support?
Up to 8 modules on each side, for a maximum of 16 modules.
What fuse does the 1769-PA4 use?
Littelfuse 02153.15MXP or Wickmann 19195-3.15A.
What is the input voltage range?
Switch-selectable 85…265V AC or 170…265V AC at 47…63 Hz.
What are the mounting options?
DIN rail or panel mounting.
