Allen-Bradley 1756-L55M16 Memory Expansion Module

The Allen-Bradley 1756-L55M16 Memory Expansion Module is a ControlLogix memory expansion that adds 7.5 MB of dedicated memory to a 1756-L55 controller, increasing the capacity for ladder logic, data blocks, and tags. Identified by part number 1756-L55M16, this module is designed to operate as an add-on memory option for the 1756-L55 family within a ControlLogix system, enabling larger programs and more extensive data handling without replacing the CPU. In practice, engineers install the L55M16 in the same chassis as the L55 CPU to expand memory across the project scope, supporting more complex automation tasks, longer data histories, and broader data logging within the controller. As part of Rockwell Automation’s memory expansion lineup for ControlLogix, the L55M16 provides a scalable upgrade path for mid- to large-scale installations that require additional memory headroom while maintaining compatibility with the L55 series and its firmware requirements.