Allen-Bradley 1756-M2 ControlLogix Controller Memory Board

The Allen‑Bradley 1756‑M2 ControlLogix Controller Memory Board is a modular expansion card that adds additional user memory to Rockwell Automation’s ControlLogix 1756 systems in the L1/L1Mx family. As part of the 1756 memory board lineup, the M2 variant installs in a compatible 1756 chassis to augment the controller’s memory space for ladder logic, data tables, and tag storage. It is documented for use with 1756‑L1 and 1756‑L1Mx controllers and carries recognized safety and compliance markings, including UL Recognized Component Industrial Control Equipment and Class I, Division 2, Group A–D listings. The module draws power from the +5V and +24V backplane rails, with peak current requirements that scale with memory configuration, and it is specified for 0° to 60°C operating temperature, -40° to 85°C storage temperature, and 5% to 95% noncondensing relative humidity. The part is identified by N #157674 on documentation and labeling. In practical terms, engineers use the 1756‑M2 when a ControlLogix rack needs more user memory without upgrading the CPU, enabling larger data tables, more tags, and expanded data handling within existing installations.