Allen-Bradley 1745-E104 Programmable Expansion Unit

The Allen-Bradley 1745-E104 SLC-100 Programmable Expansion Unit expands the I/O capacity of Rockwell Automation's SLC-100 PLCs by providing 10 discrete inputs and 6 relay-style outputs for additional sensing and switching in automation tasks. As part of the SLC-100 expansion family, it is designed to connect to a SLC-100 processor unit to extend the controller’s I/O for machine-control and process applications. In catalogs it is commonly listed as a BASIC EXPANSION UNIT (1745-E104B) in some listings. The outputs are relay-based, enabling connection to external circuits, while the inputs accept standard discrete signals from sensors and switches. This expansion module is associated with the older 1745 SLC-100 family and is used to scale I/O in legacy manufacturing and automation installations.