Allen-Bradley 1747-L542 SLC 500 CPU Controller

The Allen-Bradley 1747-L542 SLC 500 CPU Controller is a SLC 500 series fixed-style processor (5/04) with 32K total memory that serves as the central processing unit for SLC 500 control systems. As a CPU module, it executes ladder logic, coordinates I/O scans, and manages communication across the backplane; it does not include built-in I/O. The module provides 32K memory total, typically split into about 28K for user program/data and 4K for the data table, enabling modest program size and data handling for automation tasks. It offers RS232 serial programming and DH+ communications, enabling programming from a PC or controller network through supported interface cables and network adapters. Used with external I/O racks and a backplane, the 1747-L542 integrates with other SLC 500 components to form a compact control system for machines, conveyors, and packaging lines requiring reliable, mid-range control. This processor is part of the SLC 500 family’s 5/04 line (along with 1747-L541 and 1747-L543 variants) and is suitable for legacy installations or retrofits that rely on Rockwell Automation’s ladder logic environment and compatible programming tools.