Product Overview

The Allen-Bradley 1756-L55M13 is a high-performance ControlLogix 5555 series processor designed for robust discrete, drive, motion, and process control applications. Featuring a significant 1.5 megabyte (MB) memory capacity for user data and logic, alongside 208 kilobytes (KB) dedicated to I/O memory, this controller is engineered to execute complex automation tasks with high-speed efficiency. As a Series A module, it serves as the central processing unit within a ControlLogix chassis, managing data flow across the backplane to various I/O and communication interfaces.

This processor is highly regarded for its multi-discipline control capabilities, allowing users to integrate multiple control strategies into a single platform. While the 1756-L55M13 provides expansive volatile memory for active routines, it utilizes the 1756-BA1 lithium battery to maintain the user program during power loss. For high-availability requirements, the module can be integrated into a redundant controller architecture, ensuring continuous operation in mission-critical industrial environments.

System Connectivity and Communication

The 1756-L55M13 offers extensive network compatibility, allowing it to function as a bridge between disparate industrial protocols.

• Broad Protocol Support: Native integration with EtherNet/IP, ControlNet, and DeviceNet. It also facilitates legacy connectivity via Data Highway Plus (DH+), Remote I/O, and DH-485.

• Specialized Messaging: Supports Modbus communication through ladder logic routines and high-speed synchronization via SynchLink.

• Programming Interface: Features a front-facing RS-232 serial port compatible with 1756-CP3 or 1747-CP3 cables for local configuration and programming.

• Multi-Processor Capability: Multiple 1756-L55M13 controllers can be installed in the same chassis to distribute control tasks and enhance system performance.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1756-L55M13

• Series: ControlLogix 5555 (Series A)

• User Memory: 1.5 MB (Logic/Data)

• I/O Memory: 208 KB

• Backplane Current: 1.23A @ 5.1V DC; 0.014A @ 24V DC

• Power Dissipation: 5.6 Watts

• Thermal Dissipation: 19.1 BTU/hr

• Isolation Voltage: 30V (Continuous)

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Vibration/Shock: 2g @ 10-500Hz; 30g Operational Shock

• Weight: 0.35 kg (0.77 lbs)

• Dimentions: 14.5x13x14.5cm

Reliability and Performance Standards

Designed for the rigors of the factory floor, the 1756-L55M13 maintains high operational integrity under extreme conditions. Its open-style construction is intended for installation in a protected industrial enclosure, where it can withstand significant mechanical vibration and shock. The processor’s architecture supports high-speed task execution, with multiple priorities and periodic tasks that can be fine-tuned via the Studio 5000 or RSLogix 5000 programming environment.

To ensure data persistence, the module includes a low-battery LED indicator on the front panel. While the 5555 series lacks internal nonvolatile memory (such as the CompactFlash found in later L6 series), it remains a cornerstone for legacy system support and reliable, high-density logic execution in existing 1756 infrastructure.