ASDEX Upgrade Discharge Control System—A real-time plasma control framework

Highlights: • The ASDEX Upgrade Discharge Control System (DCS) is a comprehensive control system to conduct fusion experiments. • DCS supports real-time diagnostic integration, adaptable feedback schemes, actuator management and exception handling. • DCS offers workflow management, logging and archiving, self-monitoring and inter-process communication. • DCS is based on a distributed, modular software framework architecture designed for real-time operation. • DCS is composed of re-usable generic but highly customisable components. - Abstract: ASDEX Upgrade is a fusion experiment with a size and complexity to allow extrapolation of technical and physical conditions and requirements to devices like ITER and even beyond. In addressing advanced physics topics it makes extensive use of sophisticated real-time control methods. It comprises real-time diagnostic integration, dynamically adaptable multivariable feedback schemes, actuator management including load distribution schemes and a powerful monitoring and pulse supervision concept based on segment scheduling and exception handling. The Discharge Control System (DCS) supplies all this functionality on base of a modular software framework architecture designed for real-time operation. It provides system-wide services like workflow management, logging and archiving, self-monitoring and inter-process communication on Linux, VxWorks and Solaris operating systems. By default DCS supports distributed computing, and a communication layer allows multi-directional signal transfer and data-driven process synchronisation over shared memory as well as over a number of real-time networks. The entire system is built following the same common design concept combining a rich set of re-usable generic but highly customisable components with a configuration-driven component deployment method. We will give an overview on the architectural concepts as well as on the outstanding capabilities of DCS in the domains of inter-process communication, generic feedback control and pulse supervision. In each of these domains, DCS has contributed important ideas and methods to the on-going design of the ITER plasma control system. We will identify and describe these essential features and illustrate them with examples from ASDEX Upgrade operation