Allen-Bradley 1747-L542 SLC 500 CPU Processor Module

Allen-Bradley 1747-L542 is a SLC 500 Series CPU Processor Module (SLC 5/04) designed for modular control in Rockwell Automation systems. This CPU provides 32 KB of user memory for ladder logic and data and is intended for use in a 1747 modular chassis with a RUN/PROG/FLT front switch and a detachable key for secure mode selection. It offers DH+ (Data Highway Plus) and RS-232 serial communications for programming and data exchange, and is compatible with the RSLogix 500 programming environment. The 1747-L542 runs on 5–24 V DC supply and is available in standard form or conformal-coated variant (1747-L542-CC) for harsh environments. As part of the Series 1 SLC 500 ecosystem, this CPU supports up to 8,192 digital I/O points across configured I/O modules, enabling scalable control for manufacturing equipment. It includes Flash EEPROM for non-volatile program storage, preserving logic across power cycles and simplifying field updates in legacy automation tasks.