Loss-less data acquisition system for SST-1

SST-1 being steady-state Tokamak having a discharge duration of 1000 s demands a data acquisition system (DAS) which is capable enough to acquire data loss lessly from slow diagnostics. The needs of loss-less continuous acquisition have a significant effect on selection of acquisition hardware. The evolution of DAS for steady-state operation of Tokamaks has been technology-driven. The paper describes the various needs of SST diagnostics and our selection of the most suitable configuration for long-duration discharges. Here PXI bus, which is an extension of the widely accepted PCI bus, has been evaluated on the most commonly used platform like Windows with normally available PCs. For slow diagnostics, the PXI-based system with 48 channels was evaluated for continuous, single-shot and windowed acquisition. In the case of continuous acquisition, it acquires data from 48 channels at 10 kHz sampling rate and pushes all the 48 data channels on the network as well as writing to the hard disk simultaneously. A client utility also has been developed to view the data from any network node.