THE USE OF INDUSTRIAL TYPE CONTROL AND MONITORING COMPONENTS FOR A LARGE FUSION EXPERIMENT

RFX is one of the large nuclear fusion experiments within the framewor k of the co-ordinated nuclear fusion research programme of the Europea n Community. During the control system design phase in 1986, the incre ase in power and flexibility of industrial type programmable controlle rs lead to the decision for a complete physical split of control, moni toring and data acquisition functions according to speed requirements, allowing the exploitation of the relative advantages of both CAMAC an d programmable controllers. The 'slow' control and monitoring function s (for about 4000 digital and 200 analog I/O signals with scanning tim es of similar to 1 second) have been implemented using a series of net worked industrial PLCs and personal computers. This has allowed us to choose from a wide range of off-the-shelf hardware and software compon ents for the plant interface and to utilize specialized expertise from the industrial field for the application software implementation. The paper gives the expectations and results gained from this design choi ce and how it has influenced the decisions for the evolution of the sy stem over the next few years with the utilization of new industrial ha rdware components. Details are also given regarding the system integra tion (via the Ethernet network) with the VAX-based CAMAC frontend fast control and data-acquisition system.