Development of a high-performance control system by decentralization with reflective memory on QUEST

Makoto Hasegawa, Kazuo Nakamura, Hideki Zushi, Kazuaki Hanada, Akihide Fujisawa, Osamu Mitarai, Kazutoshi Tokunaga, Hiroshi Idei, Yoshihiko Nagashima, Shoji Kawasaki, Hisatoshi Nakashima, Aki Higashijima

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The plasma control system (PCS) of QUEST was a centralized system, which lost its scalability because of the overload imposed on its central processing unit (CPU) of the PCS, making it impossible to add new functions. Thus, the PCS is distributed into a main workstation (WS) and subsystem (SS) with a reflective memory (RFM) in order to share data between these systems so as to mitigate the load on each system. As a result, 128 double-precision floating-point numbers (DBLs) can be transferred from the SS to the WS with a maximum latency of 250 μs. The WS and the SS each have quad-core CPUs, and tasks are executed in parallel. Although one of the four cores is intermittently occupied by up to 90% by this transaction, the occupation is normally 60%. A time correction procedure is used to map the recorded data sets on the WS and the SS to a common time base by referring to the time difference between two systems.

Original languageEnglish
Pages (from-to)629-632
Number of pages4
JournalFusion Engineering and Design
Publication statusPublished - Oct 1 2015

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • General Materials Science
  • Mechanical Engineering


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