Rapid prototyping of advanced control schemes in ASDEX Upgrade

Abstract The integration of advanced control schemes is becoming more important as the development of fusion experiments progresses. The ASDEX Upgrade discharge control system (DCS) is designed to be adaptable via configuration, no recompilation is necessary to tailor the behaviour of the control system. In order to enable advanced control schemes the required information has to be available during the discharge. With the DCS satellite concept the control system can easily be extended by including, e.g. diagnostics, actuators and data processing nodes. In this paper the extension of DCS for rapid prototyping of control schemes is discussed. To easily add and modify input signals used for advanced control schemes, without the requirement to have expert knowledge of the control system by the experimentalist, a new application process (AP) has been implemented using the C++ Mathematical Expression Toolkit Library (ExprTk), which enables the inclusion of run-time mathematical expressions into DCS. The AP is operated separately from the central DCS as a DCS satellite. This is done to be able to test and validate the calculations without having to make changes to DCS. For tokamak operation, disruptions pose a major threat especially for large devices such as ITER. Therefore, disruption avoidance is an active field of research and the inclusion of avoidance schemes into DCS as part of exception handling is ongoing. For the case of H-Mode density limit disruptions an avoidance scheme using central heating has been implemented and successfully tested on ASDEX Upgrade, exploiting these new features for rapid development and testing.