The Tore Supra LHCD control system: new improvements using PLCs and state machines

The Tore Supra lower hybrid (LH) control system has been in operation for 10 years. Although its control system has given excellent service, it is an ageing system, and incompatible with many modern components and techniques. Hence, in order to improve the LH systemʹs reliability, efficiency, compatibility and visibility, a new design of its control system was undertaken. A solution based on modern programmable logic controller coupled with a fast logic hardware ‘state machine’ has been selected as a replacement. This can handle the ‘state diagram’ and associated safety interlock functions for each klystron with the required time response. This paper presents the association of this state machine for fast control with the PLC for slow control, a PC based human interface, and all the control and process diagnostic functions which complete this Tore Supra LH control and security system.