A multiplatform framework for real-time control in nuclear fusion devices

The paper discusses the requirements and presents an architectural overview of a new general-purpose framework for real-time control, currently under development at the RFX laboratory. This represents the third generation of control framework developed at RFX. It takes into account the experience gained in the development of the previous frameworks and exploits the evolution of computer technology, in particular the evolution of Linux towards real-time functionality and the availability of multi-core CPUs in most general-purpose computing boards. The framework will supervise data flow among the participating components, which may produce data, consume data, or apply some sort of computation. The lessons learnt after five years of operation and maintenance of the real-time control system of RFX are first presented, outlining in particular which design choices proved successful and which would have required a different approach. The general requirements of a real-time system for fusion devices are then discussed in depth in order to justify the architectural choices presented afterwards. Some system components have been already developed, while the architecture of others is still being refined. In particular, we are going to integrate the infrastructure layer of the new framework with a real-time framework recently in use at JET. The aim of this collaboration is a general purpose real-time system which can be used on both experiments.