Remodeling of JT-60 discharge control system

Remodeling of the JT-60 discharge control system (DCS) is initiated to minimize the cost and time for hardware maintenance and software development. Three principles have been adopted for remodeling. (1) The functions of the DCS must remain intact. (2) The shutdown period must be minimized to maximize JT-60 experiment time. To realize the new DCS, (3) a combination of the host workstation (WS) and target Versa Module Europe (VME)-bus system with real time OS was chosen as the fundamental structure. The prototype DCS was designed and tested to evaluate the performance of the converted discharge sequential control software modules and the message communication program. The new configuration of the DCS and procedure of smooth remodeling without shutdown is described in detail.