Allen-Bradley 1771 Series Modules | 1771-P5E Power Supply

Technical Dossier

Product Details And Specifications

Allen-Bradley 1771 Series: Comprehensive Module Range and Technical Overview

The Allen-Bradley 1771 series is the foundational I/O platform of the Rockwell Automation PLC-5 programmable controller family. Deployed across global heavy industry — including petrochemical refineries, nuclear power stations, offshore platforms, pulp and paper mills, and continuous-process chemical plants — the 1771 backplane architecture has accumulated decades of installed base that remains active in facilities where replacement of the control layer is not economically or operationally viable. The 1771 chassis accepts a standardized range of I/O, communication, and power modules via a parallel backplane bus, making it one of the most extensively documented and sourced legacy PLC platforms in the industrial automation aftermarket.

The Evolution of 1771 Architecture

The 1771 platform was introduced by Allen-Bradley in the late 1970s as part of the PLC-2 and later PLC-5 controller ecosystems. The architecture uses a parallel I/O backplane with a fixed slot-addressing scheme, where each module occupies one or two slots and is addressed by rack and slot number within the PLC-5 processor's I/O tree. Early 1771 chassis (1771-A1B, 1771-A2B, 1771-A3B, 1771-A4B) supported 4 to 16 I/O slots and were powered by dedicated power supply modules such as the 1771-P4S and 1771-P5E.

Through the 1980s and 1990s, the platform expanded to include high-density analog I/O, specialty function modules (PID, motion, weighing), and communication adapters for DH+, Remote I/O, and ControlNet. Rockwell Automation officially announced end-of-life for PLC-5 and 1771 hardware in 2022, with last-time-buy windows closing. The recommended migration path is to the ControlLogix 1756 platform, though migration requires full I/O rewiring and program conversion — a significant capital and engineering commitment that many facilities defer indefinitely. This lifecycle status makes reliable aftermarket sourcing of 1771 modules a critical operational requirement.

1771 Full Catalog & Functionalities (SKU List)

Power Supply Modules

• 1771-P5E: 5V DC, 10A power supply for 1771 I/O chassis; single-slot, right-end mount
• 1771-P4S: 5V DC, 5A power supply; standard chassis power for smaller rack configurations
• 1771-P6S: 5V DC, 16A high-capacity power supply for fully populated 16-slot chassis
• 1771-P7: Redundant power supply module; supports hot-standby power configurations

Digital Input Modules (DI)

• 1771-IAD: 120V AC, 16-point digital input module; standard field device interface
• 1771-IBD: 24V DC, 16-point digital input module; sink/source configurable
• 1771-ICD: 220V AC, 16-point digital input; high-voltage field wiring applications
• 1771-IG: TTL-compatible 5V DC digital input module; 32-point high-density
• 1771-IXE: Isolated 120V AC input module; 8-point, individually isolated channels

Digital Output Modules (DO)

• 1771-OAD: 120V AC, 16-point triac output module; zero-crossing switching
• 1771-OBD: 24V DC, 16-point transistor output; sourcing type
• 1771-ODD: 24V DC, 16-point transistor output; sinking type
• 1771-OW16: 16-point relay output module; dry contact, 2A per point

Analog I/O Modules (AI/AO)

• 1771-IFE: 8-channel analog input; 4–20 mA / 0–10V configurable per channel
• 1771-OFE1: 4-channel analog output; 4–20 mA current output
• 1771-OFE2: 4-channel analog output; 0–10V voltage output
• 1771-IXHR: High-resolution thermocouple/RTD input module; 4-channel

Communication & Adapter Modules

• 1771-ASB: Remote I/O adapter; connects 1771 chassis to PLC-5 via Remote I/O link
• 1771-ACN15: ControlNet adapter module; 1.5 Mbps ControlNet I/O scanner interface
• 1771-SDN: DeviceNet scanner module; manages DeviceNet network from 1771 chassis

Specialty Function Modules

• 1771-PID: Dedicated PID control module; executes up to 4 independent PID loops
• 1771-QA: Stepper motor positioning module; pulse-train output for open-loop motion

Sourcing Hard-to-Find & Obsolete 1771 Parts

With Rockwell Automation's end-of-life declaration for the 1771 platform, OEM factory stock is no longer available through standard distribution channels. DriveKNMS maintains a dedicated inventory of tested 1771 modules sourced from decommissioned plant equipment, authorized surplus, and controlled aftermarket channels. All units are inspected against original Rockwell Automation specifications prior to dispatch.

DriveKNMS provides lifecycle extension support for the 1771 series, including cross-referencing discontinued part numbers to available equivalents, identifying compatible substitute modules where direct replacements are unavailable, and supplying documentation packages for modules where original manuals are no longer accessible through Rockwell's literature library. For facilities operating under long-term maintenance contracts or regulated environments (nuclear, pharmaceutical, defense), DriveKNMS can provide traceability documentation and test records on request.

Quality Control for the 1771 Range

The 1771 backplane uses a parallel bus architecture with slot-addressed I/O communication. Each module interfaces via a 42-pin edge connector to the chassis backplane. Quality verification for 1771 modules at DriveKNMS includes: functional power-on testing under rated load conditions; backplane communication verification using a reference PLC-5 processor; channel-level I/O point testing for all digital and analog modules; isolation resistance measurement for isolated input modules (1771-IXE and equivalents); and output load testing for relay and triac output modules at rated current. Analog modules are calibrated against NIST-traceable references prior to shipment. Power supply modules (including the 1771-P5E) are tested at full rated output current with ripple and regulation measurements recorded.

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.