Overview of data acquisition and central control system of steady state superconducting Tokamak (SST-1)

Abstract

Steady State Superconducting Tokamak (SST-1) has been commissioned successfully and has been carrying out limiter assisted ohmic plasma experiments since the beginning of 2014 achieving a maximum plasma current of 75kA at a central field of 1.5T and the plasma duration ∼500ms. In near future, SST-1 looks forward to carrying out elongated plasma experiments and stretching plasma pulses beyond 1s. The data acquisition and central control system (CCS) for SST-1 are distributed, modular, hierarchical and scalable in nature The CCS has been indigenously designed, developed, implemented, tested and validated for the operation of SST-1. The CCS has been built using well proven technologies like Redhat Linux, vxWorks RTOS for deterministic control, FPGA based hardware implementation, Ethernet, fiber optics backbone for network, DSP for real-time computation & Reflective memory for high-speed data transfer etc.CCS in SST-1 controls & monitors various heterogeneous SST-1 subsystems dispersed in the same campus. The CCS consists of machine control system, basic plasma control system, GPS time synchronization system, storage area network (SAN) for centralize data storage, SST-1 networking system, real-time networks, SST-1 control room infrastructure and many other supportive systems. Machine Control System (MCS) is a multithreaded event driven system running on Linux based servers, where each thread of the software communicates to a unique subsystem for monitoring and control from SST-1 central control room through network programming. The CCS hardware and software architecture is capable to fulfill the present operation and control requirement of SST-1. The CCS is successfully validated in several operation campaigns of SST-1 since year 2013.The lossless PXI based data acquisition of SST-1 is capable of acquiring around 130 channels of the ranging from 10KHz to 1MHz sampling frequency and is capable to acquire the volume of 500Mbytes of data in each shot. The indigenously developed Matlab based software utility is being used to analyze the data. The complete system is also validated in several operation campaigns of SST-1 since year 2013.This paper will provide the overview of all the above mentioned subsystems of SST-1 DAQ and SST-1 CCS focusing on the design, architecture, performance, lesson learned and future upgrade plans.