File created by Logo! Soft Comfort, an automation application used for creating circuit programs; contains a "Ladder diagram (LAD)" that displays the different parts of the circuit program; includes inputs, rich text, outputs, timers, counters, and other functions.

The Logo! Soft Comfort program features a "drawing board" interface that organizes the positioning and linking of different program elements for creating and testing complex control programs. The program offers numerous features, such as text formatting, diagram editing, and simulation tools. To create an LLD file, select File → New → Ladder diagram (LAD), build your diagram, select File → Save or Save As..., choose the save location (it defaults to the "Program" folder), name the file, and click Save. To open an LLD file, simply double-click the file or select File → Open... in the application, navigate to your file, and click Open. To convert your diagram type from Ladder to Function Block, select File → Convert to FBD. This will change the layout of your diagram and you will then save the file as an .LSC file. NOTE: The LLD file is similar to an LSC file, which contains a function block diagram. If you're used to working with logic boxes of Boolean algebra, you should use the function block diagram.