Allen-Bradley 1720-L004 is a four-input gate card (circuit card) used as an add-on in legacy Allen-Bradley 1720 logic systems to implement basic combinational logic. The module provides four input gates, described in vendor literature as an AND-OR gates card, enabling simple pre-processing of signals before they reach the main controller. This 1720-L004 circuit card is cataloged by multiple distributors as part of the 1720 Gates family and is commonly referenced as a replacement/stock item for 1720-based automation setups.
