Contents I. Introduction
THE fusion experiment Wendelstein 7- X (W7-X) is a very complex technical system consisting of many individual control components. The components (plasma heating systems, diagnostics, power supplies, cryogenic system, …) are subordinated to the central control system. The duration of a plasma discharge is only limited by the cooling system and can be up to 30 minutes—a long time compared to the few seconds of conventional pulsed experiments. It permits to divide the discharge into individual sections aiming at a number of experiments with different physical questions during a plasma discharge. One section of the plasma discharge is called a segment. Each segment defines completely the behaviour of the components involved in the experiment at the time of the validity of the segment. Thus the planned plasma discharge consists of a chain of predefined segments to be carried out in real time.
