This lesson teaches how to interpret programmable controller ladder logic. The lesson defines the program elements of ladder logic and the functions that they perform. This includes contacts, coils, and data functions as well as many of the common ladder logic arrangements.

This lesson teaches the difference between discrete and analog control and how PLC’s implement PID control modes. It shows different hardware configurations and how process data is transmitted between components on a data highway. Programming languages including ladder logic and function block statements are presented. Additionally, the lesson shows how PLCs actually work in different process applications and some routine and preventative maintenance techniques.