Steady-state data acquisition method for LHD diagnostics

The LHD experiment has gone through 5 campaign periods over the past 4 years, during which the diagnostics data continues to grow and the primary 28 measurements produce about 620 MB/shot in 150 shot/day 3-min cycles. In 2002, 30-min long-pulse experiments will be carried out in LHD, where real-time operations are indispensable for plasma measurements and data acquisition. The new scheme for utilizing conventional CAMAC digitizers in long-pulse experiments has been discussed and examined. As a result, in LHD, CAMACs will shift into 120–180 s cyclic operation, synchronized by the diagnostic timing system. The new CompactPCI-based digitizer frontend has performed about 84 MB/s continuous acquisition in benchmarks, and has been formulated with the conventional CAMAC system to make concurrent acquisitions.