The Essentials of Process Control (EPC) range of products takes through the fundamentals and principles of process control and progresses to give them a thorough grounding in the control of physical processes. Four independent process units demonstrate level, flow,temperature and pressure as the controlled variable. The concepts of closed loop control, including on/off control, proportional control, proportional/integral and proportional/integral/derivative (PID) control can be explored and demonstrated. Some units also cover both time proportioning and analogue control of the same parameter. Each process is supplied complete with software that allows it to be controlled using a Windows PC via a USB connection. The effect of making changes to the system or to the controller configuration can be quickly investigated by applying repeatable disturbances or step changes to the process. Comparison of the responses obtained with different control settings clearly demonstrates the need for correct matching of the controller to the system characteristics. To demonstrate industrial control systems, two further controlling devices are available, a full function commercial PID controller with auto tune, and a programmable logic controller (PLC). The plc has the control algorithms implemented in ladder logic and so are fully accessible to the user. Another fundamental aspect of process control is an understanding of sensors and how they are calibrated. This is demonstrated by a sensor calibration apparatus designed specifically to demonstrate this subject.