The DIII-D multiple gyrotron control system

The recent DIII-D program to upgrade to six 1 MW gyrotrons presented the opportunity to modernize the control and instrumentation systems. The challenge of the system is to allow a small number of operators to control the gyrotrons, which have individual tuning requirements and are sourced from two manufacturers. The main user interface is written in National Instruments´ LabVIEW software. Access to PLC functions not available through the LabVIEW interface are provided by Siemens´ TISOFT and by Ci Technologies´ Citect. The computer control system uses computers connected by ethernet to distribute the control, status, and data functions. The computers which directly interface with the gyrotron system hardware use a rack-mountable and ruggedized compact PCI format. The waveform digitizers and the timing control module, which gates the high voltage power supply, the gyrotron filament boost, and sends the hardware reset and digitizer triggers, are also located in the compact PCI crate. These computers also control hardware responsible for forming the gyrotron pulse shape, programming the sweep coil waveform, setting the waveguide polarizer angles, and detecting asynchronous system events. Many control functions are handled by PLCs which are under computer control. The PLCs are responsible for the vacuum and waveguide systems, access interlocks, filament power supply control, cooling system interlocks, the high voltage power supply interface, gyrotron tank oil interlocks, and launcher mirror control.