Allen-Bradley 1756-L55 ControlLogix Processor

The Allen-Bradley 1756-L55 ControlLogix Processor is a high‑performance CPU that serves as the central controller within Rockwell Automation’s ControlLogix platform (Logix5555 family). To operate, it pairs with a memory module (for example, the 1756-L55M12 or 1756-L55M22); the latter variant provides 750 KB of user/program memory and 208 KB of non‑volatile memory when using the 1756-L55M22 option. The L55 accepts firmware up to version 16, placing it among the earlier-generation Controllers in the ControlLogix line. Electrical characteristics include a backplane current of about 1.23 A and a power dissipation around 5.6 W, with thermal dissipation near 19.1 BTU/hr. The CPU is designed for deployment in a ControlLogix chassis as the processing heart of automated machinery and processes, integrating with other ControlLogix I/O, communications, and memory modules to form scalable control solutions.