Product Overview

The Allen-Bradley 1756-L55M12 is a foundational ControlLogix 5555 processor module from Rockwell Automation’s esteemed Logix5000 family of controllers. Engineered as the central processing unit for the modular 1756 chassis-based system, this controller executes user-generated logic, manages I/O data, and facilitates communication across multiple industrial networks. The 1756-L55M12 combines a high-performance Logix5555 processing core with a dedicated 1756-M12 memory board, delivering 750 KB of user-available memory for complex control applications-1-3.

The Allen-Bradley 1756-L55M12 is distinguished by its modular architecture, which separates the controller base from the memory board, allowing for flexible memory upgrades. This particular configuration provides 750 KB of combined data and logic memory, supplemented by 208 KB of dedicated I/O memory. The controller supports a maximum of 128,000 discrete I/O points and 4,000 analog inputs and 2,000 analog outputs, making the 1756-L55M12 suitable for large-scale distributed applications-5-9. Its integrated RS-232 serial port and ControlNet coaxial port enable deterministic networking and seamless integration into distributed control architectures. As a legacy component, the 1756-L55M12 remains a critical asset for maintaining and supporting existing automation systems that require the specific performance profile of the Logix5555 generation-8-12.

Technical Specifications