1771-P4R | Allen Bradley | PLC 5 Redundant Power Supply Module

Product Overview

The Allen Bradley 1771-P4R functions as a high-performance redundant power supply module designed specifically for the 1771 Universal I/O chassis. It provides critical 5V DC backplane power to PLC-5 processors and I/O modules. This module enables N+1 redundancy configurations, allowing multiple power units to share the load and provide instantaneous failover protection. By installing the 1771-P4R, engineers eliminate the power supply as a single point of failure, ensuring continuous operation for mission-critical industrial processes that cannot tolerate unscheduled downtime.

Technical Specifications

Engineering Advantages

• Scalable N+1 Redundancy: The 1771-P4R architecture allows for parallel operation across multiple units. In a 4-unit configuration, the system delivers up to 20A of backplane current. This scalability ensures the power system grows alongside your I/O requirements while maintaining a safety buffer for hardware failures.

• Integrated Fault Diagnostics: An onboard alarm relay rated for 250V AC monitors the health of the power stage. This relay triggers immediate notification to the PLC or external monitoring systems if the output voltage deviates from specifications, allowing for proactive maintenance before a total system crash occurs.

• Seamless Failover Protection: The module includes the necessary redundancy cabling to synchronize with adjacent P4R units. This hardware-level link facilitates instantaneous load sharing and ensures that if one unit loses AC input or suffers an internal fault, the remaining units pick up the load without interrupting the PLC-5 processor.

• Robust Thermal Management: Engineered to operate at full capacity up to 60°C (140°F), the 1771-P4R withstands the elevated temperatures found in densely packed control cabinets. It utilizes a high-efficiency design to limit power dissipation to 59W, reducing the heat load on neighboring I/O modules.

• Plug-and-Play Chassis Integration: Occupying only a single slot in any 1771 Universal I/O chassis, the 1771-P4R simplifies installation. The use of standardized Wago wiring blocks (A-B PN 941274-05) ensures secure, vibration-resistant AC power and relay connections.

FAQs

• Is the 1771-P4R supplied as 100% Brand New?

  Yes. We supply this 1771-P4R power supply in 100% Brand New, original factory condition. Every unit arrives in its original Allen Bradley packaging with factory seals intact to ensure maximum reliability for your redundant power system.

• Can I mix the 1771-P4R with standard 1771-P4 supplies?

  No. The 1771-P4R contains specialized internal circuitry and cabling ports for load sharing. You must use only P4R models when building a redundant power configuration to ensure proper synchronization and fault isolation.

• What happens if I exceed the 8A current limit of a single module?

  The 1771-P4R protects itself against overcurrent conditions. However, for systems requiring more than 8A, you must install additional P4R units in an N+1 configuration. In a redundant setup, ensure the total current draw remains below the "N" capacity (e.g., if using 3 units, your load should not exceed the 14A rated capacity).

• Does the module include the redundancy cable?

  Yes. Each 1771-P4R includes the necessary redundancy cable required to link the module to its neighboring power supply. This ensures you have all components necessary for a successful failover setup upon delivery.