Product Overview

The 1785-L40L serves as a core processing unit within the Allen-Bradley PLC-5 platform, specifically optimized for high-capacity industrial automation and legacy system expansion. As an Enhanced PLC-5/40L controller, it provides a powerful solution for managing large-scale I/O configurations and sophisticated control algorithms. This module is designed to orchestrate complex operations across extensive plant floors, ensuring high-speed data execution and reliable synchronization of field devices.

Engineered for durability in harsh manufacturing environments, the 1785-L40L integrates seamlessly into existing 1771-style universal I/O chassis. It is particularly valued in sectors such as automotive, heavy manufacturing, and chemical processing where maintaining legacy infrastructure with proven, high-reliability hardware is a priority.

Technical Specifications

• Memory Capacity: 48K Words (SRAM)

• Total I/O Maximum: 2,048 (Any mix) or 2,048 Complementary

• I/O Chassis Support: Up to 16 Extended Local I/O chassis

• Communication Interfaces: Data Highway Plus (DH+), Remote I/O (Scanner or Adapter mode)

• Programming Ports: Parallel port for high-speed programming; Serial RS-232C/422A/423A

• Backplane Current Load: 3.3A @ 5V DC

• Clock/Calendar Accuracy: ±1 minute per month at 60°C

• Typical Scan Time: 0.5 ms per K (Boolean logic)

• Safety Certifications: UL, CE, C-TICK, CSA

• Dimensions: 4.8 x 16.7 x 27.4 cm

• Weight: 1.38 kg

Performance and Network Capabilities

The 1785-L40L CPU Module is distinguished by its flexible networking options. It supports multi-node DH+ communication for peer-to-peer data exchange and programming, alongside Remote I/O capabilities that allow the processor to control hardware located far from the main chassis. The "L" designation indicates its specialized support for extended local I/O links, which facilitates high-speed communication between the processor and multiple I/O chassis without the latency typically associated with standard remote links.

The module features comprehensive self-diagnostics and voltage isolation to protect the internal logic from electrical transients. User memory is protected by a replaceable battery, ensuring program retention during power loss. Its compatibility with the broad 1771 I/O family allows for highly customized system architectures, ranging from simple digital control to advanced analog and motion integration.