Allen-Bradley 1747-L553 SLC 500 Ethernet Controller

The Allen-Bradley 1747-L553 is a SLC 5/05 processor module for the SLC 500 modular PLC family, delivering 64K of user memory and built-in Ethernet and RS-232 communications. It provides a native 10Base-T Ethernet port alongside an RS-232 serial interface for DH-485, DF1, or ASCII communications, enabling both networked control and legacy device integration on the same CPU. As a SLC 5/05 CPU, it executes ladder logic within 64K of user memory and is typically programmed with RSLogix 500. In typical installations, the L553 plugs into a SLC 500 rack with other I/O modules, offering Ethernet connectivity for plant-wide monitoring, remote I/O access, or PLC-to-PLC communication without requiring a separate Ethernet module. The 1747-L553 is one of the SLC 5/05 processors (along with the 1747-L551 and 1747-L552) that combine an Ethernet port and RS-232 port in a single CPU, making it a suitable choice for maintaining legacy automation while adding network access.