Allen-Bradley 1756-L55 Programmable Logic Controller Processor

Allen-Bradley 1756-L55 Programmable Logic Controller Processor with 1756-M13 Memory Expansion (NO COVER) is a Rockwell Automation ControlLogix CPU in the Logix5555 family, engineered for large, memory‑intensive automation tasks. The attached 1756-M13 memory expansion provides 1.5 MB of RAM for user programs and data, plus 208 KB of nonvolatile backup memory to retain essential information across power cycles. The L55 controller requires a memory module to boot, making this pairing a common choice for configurations demanding substantial program size and tag density in industrial control systems. The unit ships with the memory expansion installed and the cover omitted, so plan for a replacement cover or suitable enclosure in your cabinet. Typical applications include complex process control, machine automation, and high‑channel I/O integrations where substantial logic and data storage are needed within a single ControlLogix chassis.