Now that you've been introduced to the more common input and output devices that make up a ladder diagram, next time we'll explore in more depth how 2- and 3- wire control circuits tie the control ...

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 ...

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