Prototype Real Time System for Fault Finding and Control for High Power RF System at 3.7 GHz

Abstract

Lower Hybrid current Drive system (LHCD) is a vital system in Steady State Super Conducting Tokamak-1 (SST-1). It is used for non inductive current drive and heat- ing Experiments. LHCD System houses 4 klystron based high power RF system at 3.7 GHz. For the protection and reliable operation of High Power RF System it is equipped with interlocks and inbuilt protections. VxWorks, a Real Time Operating Sys- tem(RTOS) is used for real time data acquisition ( 1-10μs), control ( 100μs) and for long term operation and simulation of high power components. RTAI (Real Time Application Interface) is freely available linux based real time operat- ing system (RTOS). The real time acquisition codes and control has been developed us- ing RTAI and cross compiled with GNU cross compiler. These cross compiled programs have been executed on target machine with help of U-Boot and ELDK(Embedded Linux Development Kit). Analysis code has been developed using RTAI-lab, scilab and MD- Splus. Data visualization module, data archival module and service invocation archi- tecture have been developed at RF lab. For controlling the high power RF system, the control module has been developed which can control the system by means of the real time kernel tasks. This system has been tested with VMEbus (Versa Module Eurocard) and PowerPC(Motorola PPC604) based data acquisition and control setup at RF Lab. VTR812 with 8 channels has been used as data acquisition card. The real time system and its components which has been developed and tested at RFlab were linux based freely available and have no cost. So real time controls are developed which are free and have latency in order of 100 microseconds.