Allen-Bradley 1747-L542 SLC 5/04 Processor

Allen-Bradley 1747-L542 SLC 5/04 Processor is a compact CPU module for the SLC 500 family, designed to run ladder logic in small- to mid-size control racks. It provides 32K memory for program and data and includes an RS-232 serial port for programming and diagnostics, as well as a DH+ (Data Highway Plus) port for networked I/O and device communication. As a member of the SLC 5/04 line, the L542 plugs into a 1747 backplane and works with 1747 I/O modules to manage discrete control, sequencing, and basic process tasks across DH+ networks. The L542 is one of several 5/04 CPUs used in legacy plants (along with L541 and L543), offering compatibility with classic RSLogix 500 workflows and a broad ecosystem of Allen-Bradley peripherals. Designed for retrofit and expansion in existing SLC 500 racks, the 1747-L542 integrates with 1747 I/O modules and DH+ networks, enabling reliable, cost-effective automation upgrades without replacing legacy equipment. Common applications include small conveyors, machine tending, and batch-handling tasks in aging manufacturing environments where SLC 500 hardware remains active.