Allen-Bradley 1747-L542 SLC 500 Processor Module

Allen-Bradley 1747-L542 SLC 500 Processor Module is a Series 1 SLC 5/04 CPU for the Rockwell Automation SLC 500 modular controller family. This Rev3 processor ships with 1747-OS401 firmware (FRN 7) and 32K of memory, partitioned as 28K words for the program and 4K words for data, enabling compact ladder logic applications with moderate data handling. The unit provides an RS-232 serial port and a DH+ (Data Highway+) port for local communications with other controllers, devices, and programming equipment. Designed for scalability, the 1747-L542 supports up to three local I/O chassis and a total of 30 I/O module slots within those chassis, making it suitable for mid-size machine control and automation tasks. Typical applications include discrete manufacturing line control, packaging machines, conveyors, and simple process sequencing, where a robust, familiar Rockwell control platform is desired and legacy 1747 modules are already in use. The processor is part of the SLC 500 ecosystem, enabling interface with compatible 1747 I/O modules and networks that rely on RS-232 and DH+ communication to collect data, drive actuators, and synchronize with other controllers in legacy automation setups.