Instrumentation, data acquisition and controls for temperature measurement of cold surfaces at 4.5 K and 80 K of SST-1 machine

Two-temperature regimes have been envisaged for the SST-1 machine, 80 K on the thermal shield and 4.5 K on the superconducting magnet system. The aim of temperature measurement is two folds (1) to monitor the temperature distribution as well as process parameters (ii) to achieve controlled cool down from 300 K to 4.5 K and 80 K. Temperature sensors have been mounted on cold surfaces at required locations to ease the operation during cool down and steady state. Techniques employed for temperature measurement and controls are based on continuous resistance measurement. Cernox (TM) sensors (Lakeshore made) and PT-102 have been used for the temperature measurement at 4.5 K and 80 K surfaces respectively. The data acquisition system (DAS) has been indigenously developed using 4-20 mA current loop temperature transmitter, which provided better functioning in terms of flexibility. The control functioning has been designed and developed using programmable logic controller with direct interfacing of the transmitter. The temperature data is obtained at the supervisory control and data acquisition of dedicated node. The developed DAS has been found to be very reliable and satisfactory.