Design and implementation of electromagnetic diagnostics electronics in SST-1 Tokamak

Electromagnetic (EM) Diagnostics is one of the most important diagnostics tools to measure the key parameters such as the current, position, loop voltage and Magneto Hydro Dynamic MHD activities of the plasma in SST1 (Steady State Tokamak), designed for long pulse (1000 s) operation. A frontend electronic scheme for conditioning the dynamic (10mV to 2V) range of signals over the entire time span is designed that incorporates features such as remote parameter setting, self-test and calibration, saturation detection, storing of default values and system health monitoring and also adopts methodologies to address issues related to noise, signal and power integrity and low channel density. The entire scheme is implemented in a 3U size chassis. 28 numbers of channels of AD215 isolation amplifiers are integrated in 7-modules with 4-channels/module. Each module is designed to operate in different modes like attenuation, amplification, calibration, dc error check, self-test and standby. These modes of operation can be selected using a LabVIEW based GUI from a remote PC. A TMS320F38335 based controller module is designed for this purpose and is being integrated in the chassis. The controllers of all the chassis of EM diagnostics are interconnected through CAN network and connected to a remote PC through Ethernet. A discussion on the design, implementation and results of this electronic scheme is presented in this paper.