Logical functions. When studying logic, one must begin with the basic functions. Input values can be combined using the logical AND, OR, and exclusive OR (XOR) functions (Fig. 1 at right). Logic gates ...

The ladder diagram shows you what the inputs and outputs are, and it shows how each output responds to a given input change. This is, in fact, what makes a ladder diagram especially useful for ...

Ladder logic still has the edge in visual troubleshooting, but the shear efficiency and interoperability of higher-level languages will be enticing.