Author: Nobusaka, H.
Paper Title Page
S12FC09 Very Fast Feedback Control of Coil-Current in JT-60 Tokamak 442
 
  • T. Aoyagi, Y. Matsuzaki, H. Nobusaka, M. Takahashi, T. Terakado, J. Yagyu
    JAEA/NAKA, Ibaraki-ken, Japan
 
  A direct digital control (DDC) system is adopted for controlling thyristor converters of power supplies in the JT-60 tokamak built in 1984. Microcomputers of the DDC were 5 MHz i8086 microprocessor and programs were written by assembler language and the processing time was under l ms. They were, however, too old in hardware and too complicated in software. New DDC system has been made in the JT-60 Upgrade (JT-60U) to control the power supplies more quickly under 0.25 and 0.5 ms of the processing time and also to write the programs used by high-level language. The new system consists of a host computer and five microcomputers with microprocessor on VMEbus system. The host computer AS3260 performs on-line processing such as setting the DDC under the discharge conditions and so on. Functions of the microcomputers with a 32-bit, 20 MHz microprocessor MC68030, whose OS are VxWorks and programs are written by C language, are real-time processing such as taking in instructions from a ZENKEI computer and in feedback control of currents and voltages of coils every 0.25 and 0.5 ms. The system is now operating very smoothly.  
DOI • reference for this paper ※ doi:10.18429/JACoW-ICALEPCS1991-S12FC09  
About • Received ※ 02 December 1991 — Accepted ※ 02 January 1992 — Issued ※ 04 December 1992  
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