Allen-Bradley 1771 PC Board Modules SP-110997 SP-105044 105043-01

Technical Dossier

Product Details And Specifications

Allen-Bradley 1771 Series Technical Notes

The Allen-Bradley 1771 series, manufactured by Rockwell Automation, represents one of the most widely deployed programmable controller (PLC) platforms in global heavy industry. Installed across petrochemical refineries, nuclear power generation facilities, offshore oil platforms, and large-scale chemical processing plants, the 1771 I/O chassis system established the architectural standard for rack-based distributed control throughout the 1980s and 1990s. The SP-110997, SP-105044, and 105043-01 are factory-level PC board assemblies used in the repair and refurbishment of 1771-series modules and associated PLC-5 processor hardware. These board-level components are critical for sustaining legacy installations where full module replacement is cost-prohibitive or where OEM supply has been discontinued.

The Evolution of 1771 Architecture

The 1771 platform was introduced by Allen-Bradley in the late 1970s as a modular, rack-based I/O system designed to interface with the PLC-2 and later PLC-5 processor families. The architecture is built around a passive backplane chassis (1771-A1B through 1771-A4B series) that accepts up to 16 I/O modules per rack, communicating via a parallel I/O bus at 5 VDC logic levels.

Over successive hardware generations, the 1771 system expanded to support remote I/O (RIO) via the 1771-ASB adapter, high-speed counter modules, analog I/O with 12- and 16-bit resolution, and specialty modules for motion, temperature, and PID control. The PLC-5 processor family (5/10, 5/15, 5/20, 5/25, 5/30, 5/40, 5/60, 5/80) served as the primary CPU platform for 1771 racks through the 1990s.

By the mid-2000s, Rockwell Automation formally transitioned new designs to the ControlLogix (1756) and CompactLogix (1769) platforms. The 1771 series entered its end-of-life phase, with OEM production of many modules ceasing between 2010 and 2018. However, the installed base remains extensive. Compatibility challenges arise primarily from the parallel bus architecture, which is incompatible with modern EtherNet/IP-native systems without gateway hardware. Board-level components such as SP-110997, SP-105044, and 105043-01 are therefore essential for sustaining existing 1771 hardware rather than replacing it.

Allen-Bradley 1771 Full Catalog & Functionalities (SKU List)

Controllers & Processors

• 1771-P4S: 1771 chassis power supply, 5 VDC, 10A output for full-size racks
• 1771-P7: Redundant power supply module for high-availability 1771 chassis
• 1771-OBD: 16-point 24 VDC sourcing discrete output module
• 1771-IBD: 16-point 24 VDC sinking discrete input module
• 1771-OAD: 16-point 120 VAC discrete output module, triac-switched
• 1771-IAD: 16-point 120 VAC discrete input module
• 1771-IFE: 8-channel analog input module, 12-bit resolution, 4–20 mA / 0–10 V
• 1771-OFE1: 4-channel analog output module, 12-bit, current/voltage selectable
• 1771-ASB: Remote I/O adapter module, connects 1771 rack to PLC-5 RIO network
• 1771-SDN: DeviceNet scanner module for 1771 chassis integration
• 1771-IXHR: High-resolution thermocouple input module, 4-channel, ±0.1°C accuracy
• 1771-IXE: Thermocouple/millivolt input module, 8-channel
• 1771-HSC: High-speed counter module, up to 50 kHz input frequency
• 1771-DA: ASCII/BASIC module for serial communication and custom ladder logic extensions
• 1771-QA: Servo positioning module for single-axis motion control via 1771 backplane
• SP-110997: OEM PC board assembly; internal repair component for 1771-series module refurbishment
• SP-105044: OEM PC board assembly; logic-level board used in PLC-5 / 1771 module repair
• 105043-01: OEM PC board sub-assembly; associated with power regulation or I/O interface circuitry in 1771 hardware

Sourcing Hard-to-Find & Obsolete 1771 Parts

DriveKNMS maintains a dedicated inventory of 1771-series modules, chassis, power supplies, and board-level components including SP-110997, SP-105044, and 105043-01. Our sourcing model is built around lifecycle extension support: we acquire, test, and certify surplus and refurbished 1771 hardware to provide a reliable supply chain for facilities that cannot justify a full ControlLogix migration. We support emergency breakdown orders, planned maintenance procurement, and long-term spares agreements for 1771 installations with multi-year operational horizons.

Quality Control for the 1771 Range

PC board assemblies such as SP-110997, SP-105044, and 105043-01 undergo a structured inspection and functional verification process prior to dispatch. Each board is visually inspected under magnification for solder joint integrity, component damage, and corrosion on edge connectors. Electrolytic capacitors are tested for ESR (equivalent series resistance) and capacitance value against OEM specification. Logic ICs are verified for correct part marking and functional response.