In this introduction session, the PLC Architecture will be presented. The International Electrotechnical Commission (IEC) 61131-3, Structured Text (ST) language, will be introduced along with the explanation of logic operators. Also, the discussion on building an Arduino PLC using off-the-shelf components will be presented. Attendees will learn how to install the plcLib library within the Arduino Integrated Development Environment (IDE) for programming the Arduino Mega2560 prototyping board. A basic Ladder Logic Hello World device will be the introductory plcLib application programmed for the Arduino Mega2560.