BAS: What is it and how does it simplify our lives? Building automation describes the advanced functionality provided by the control system of a building. A building automation system (BAS) is an example of a distributed control system. The control system is a computerized, intelligent network of electronic devices designed to monitor and control the mechanical, electronics, and lighting systems in a building. This interactive online course will discuss the BAS topology and will include topics such as primary and secondary bus, as well as analog and digital input and output.