Real-Time Data Acquisition System for Control and Long-Pulse Operation in Tore Supra

Balme, S.; Buravand, Y.; Fejoz, P.; Leroux, F.; Pastor, P.; Ravenel, N.; Spuig, P.

doi:10.13182/fst09-a9177

“…Since the closed feedback loops typically require the latency time as about s or less, the performance optimization had been primarily made not on their high data throughput but on their low latency ability. Therefore, the real-time feedback controls were ordinarily made on a limited number of measured signals, never on full size of raw data [7].…”

Section: Steady State Operation In Lhdmentioning

confidence: 99%

Real-Time Data Streaming and Storing Structure for the LHD’s Fusion Plasma Experiments

Nakanishi

¹

,

Ohsuna

²

,

Kojima

³

et al. 2016

IEEE Trans. Nucl. Sci.

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The LHD data acquisition and archiving system, i.e., LABCOM system, has been fully equipped with high-speed real-time acquisition, streaming, and storage capabilities. To deal with more than 100 MB/s continuously generated data at each data acquisition (DAQ) node, DAQ tasks have been implemented as multitasking and multithreaded ones in which the shared memory plays the most important role for inter-process fast and massive data handling. By introducing a 10-second time chunk named "subshot," endless data streams can be stored into a consecutive series of fixed length data blocks so that they will soon become readable by other processes even while the write process is continuing. Real-time device and environmental monitoring are also implemented in the same way with further sparse resampling. The central data storage has been separated into two layers to be capable of receiving multiple 100 MB/s inflows in parallel. For the frontend layer, high-speed SSD arrays are used as the GlusterFS distributed filesystem which can provide max. 2 GB/s throughput. Those design optimizations would be informative for implementing the next-generation data archiving system in big physics, such as ITER.

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“…Since the closed feedback loops typically require the latency time as about 10 −3 s or less, the performance optimization had been primarily made not on their high data throughput but on their low latency ability. Therefore, the real-time feedback controls were ordinarily made on a limited number of measured signals, never on full size of raw data [7]. Being free from the fast feedback controls, the LHD system has been able to concentrate the performance optimization upon the highest data throughput.…”

Section: Steady State Operation In Lhdmentioning

confidence: 99%

Realtime data streaming and storing structure for LHD's fusion plasma experiments

Nakanishi

¹

,

Ohsuna

²

,

Kojima

³

et al. 2014

2014 19th IEEE-NPSS Real Time Conference

0

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The LHD data acquisition and archiving system, i.e., LABCOM system, has been fully equipped with high-speed real-time acquisition, streaming, and storage capabilities. To deal with more than 100 MB/s continuously generated data at each data acquisition (DAQ) node, DAQ tasks have been implemented as multitasking and multithreaded ones in which the shared memory plays the most important role for inter-process fast and massive data handling. By introducing a 10-second time chunk named "subshot," endless data streams can be stored into a consecutive series of fixed length data blocks so that they will soon become readable by other processes even while the write process is continuing. Real-time device and environmental monitoring are also implemented in the same way with further sparse resampling. The central data storage has been separated into two layers to be capable of receiving multiple 100 MB/s inflows in parallel. For the frontend layer, high-speed SSD arrays are used as the GlusterFS distributed filesystem which can provide max. 2 GB/s throughput. Those design optimizations would be informative for implementing the next-generation data archiving system in big physics, such as ITER.

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“…Real-time feedback algorithms are used extensively in Tore Supra for a wide variety of safety and control functions [10]. Two of them are described here.…”

Section: "Industrialization" Of Probe Measurements By Real-time Feedbmentioning

confidence: 99%

Electric Probes in Tokamaks: Experience in Tore Supra

Gunn

¹

,

Pascal

²

,

Saint‐Laurent

³

et al. 2011

Contrib. Plasma Phys.

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Efforts to provide regular, automatic, and reliable reciprocating probe measurements in the scrape-off layer of the Tore Supra tokamak are described. Real time feedback on fast magnetic reconstruction is used to control the probe position relative to the last closed flux surface, while analysis of the current-voltage characteristics is used to adapt the voltage waveform applied to the probe, improving the dynamic range of the measurement. A large probe head is employed to ensure operation in the strongly magnetized plasma regime. Concave collectors embedded in the probe head, so-called "tunnel probes", are shown to be immune to sheath expansion effects, providing absolutely calibrated measurements of parallel ion current density.

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Real-Time Data Acquisition System for Control and Long-Pulse Operation in Tore Supra

Cited by 6 publications

References 3 publications

Real-Time Data Streaming and Storing Structure for the LHD’s Fusion Plasma Experiments

Real-Time Data Streaming and Storing Structure for the LHD’s Fusion Plasma Experiments

Realtime data streaming and storing structure for LHD's fusion plasma experiments

Electric Probes in Tokamaks: Experience in Tore Supra

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