Design and Development of Fast Protection and Fast Monitoring Module Compatible With NI Compact RIO System for ITER-India Gyrotron Test Facility

The ITER electron cyclotron (EC) system will have gyrotron sources used for plasma heating and current drive applications. During gyrotron operation, different faults may be encountered and in the case of critical faults, the High Voltage Power Supplies (HVPS) should be switched off in <; 10 μs time scale, which otherwise could damage the internal components of a gyrotron tube. Also during the operation, the main operating parameters need to be acquired on fast time scales (~5 Msps) to know the gyrotron output characteristics. A solution is required catering to both the requirements, which should be cost-effective, and also comply with recommended hardware and software framework. In this context, a custom prototype module compatible with NI-CompactRIO (NI-cRIO) system is under development for ITER-India Gyrotron Test Facility (IIGTF). The module has protection and monitoring functions both in parallel in a single unit. It has a transmitter (TX) and receiver (RX) card connected optically to complete the link. The TX has fast sampling analogto-digital converter (ADC), fast comparator, field-programmable gate array (FPGA), and an optical transmitter. The TX sends monitoring and trip information optically to the RX. The RX card has an optical receiver, FPGA, and digital-to-analog converter (DAC), which generates back the original signals. The heart of the module is FPGA logic, which performs encoding and decoding (as per 8b10b standard) of ADC serial data, thereby eliminating the use of any serial converter ICs. The module can be plugged into the cRIO chassis and also can be used as a standalone module. This article discusses the concept, design, development, and test results of fast protection and fast signal monitoring module.