Allen-Bradley 1747L541 SLC 500 Processor Module

The Allen-Bradley 1747-L541 is a SLC 5/04 processor module for the SLC 500 modular PLC family, Series C. It provides 16K words of user memory for ladder logic programs and supports up to 4,096 discrete inputs and 4,096 discrete outputs, with support for up to 480 analog I/O points across compatible modules. The CPU features dual built-in communications ports—Data Highway Plus (DH+) for networked devices and RS-232 for direct programming and diagnostics—enabling both field connectivity and host PC access without additional interface cards. This processor is designed to install in a 1746 backplane and delivers deterministic operation with program scan times around 0.9 ms per keyword and I/O scan times around 0.225 ms, depending on configuration. The 1747-L541 is cataloged in its family as 1747-L541 (also seen as 1747-L541/C in some revision notes) and represents the 5/04 line within the SLC 500 ecosystem, a legacy, modular PLC platform used for discrete control tasks where a compact, economical CPU is appropriate.