6. LD language

The Ladder Diagram (LD) language is a graphical representation of Boolean equations combining contacts (input arguments) with coils (output results). The LD language lets you describe tests and modifications of Boolean data using graphic symbols placed in a diagram. LD graphic symbols are organized like the elements of an electrical contact diagram. LD diagrams are connected on the left and right to vertical power bars. Here are the basic graphic components of an LD diagram:

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