A novel method of sensing temperatures of magnet coils of SINP-MaPLE plasma device

Abstract

A set of 36 magnet coils is used to produce a continuous, uniform magnetic field of about 0.35 Tesla inside the vacuum chamber of the MaPLE Device, a linear laboratory plasma device (3 m long and 0.30 m in diameter) built for studying basic magnetized plasma physics phenomena. To protect the water cooled-coils from serious damage due to overheating temperatures of all the coils are monitored electronically using low cost temperature sensor IC chips, a technique first being used in similar magnet system. Utilizing the Parallel Port of a Personal Computer a novel scheme is used to avoid deploying microprocessor that is associated with involved circuitry and low level programming to address and control the large number of sensors. The simple circuits and a program code to implement the idea are developed, tested and presently in operation. The whole arrangement comes out to be not only attractive, but also simple, economical and easy to install elsewhere.

The MaPLE device: A linear machine for laboratory studies of the magnetized plasma physics phenomena

“…The MaPLE device (Pal R. et al 2010;Biswas et al 2011;Biswas 2013;Pal A. M. et al 2014) is a linear machine with a cylindrical vacuum vessel where an axial, dc magnetic field is produced and the field is uniform over the radius and a length of 1.5 m inside the vacuum vessel. Schematic diagram of the device is shown in Fig.…”

“…During the course of an experiment, a fault in the water flow system may develop, or a flow-impeding bubble may form inside any of the coils, or chiller may stop working due to several kinds of malfunctioning and all of this can cause the temperature of the relevant coils to rise high, leading to the permanent damage due to overheating. Therefore, it is absolutely necessary to monitor the temperatures of all of the 36 sub-coils and take safety action if the temperature of any one of them goes high (Pal A. M. et al 2014). For this purpose, a small circuit board containing a temperature sensor DS1620 IC chip † is mounted at the water outlet of each of the 36 sub-coils.…”

“…Detail design, installation and operation of this safety system are given in the Ref. Pal A. M. et al (2014).…”

“…CN1: parallel port, CN2: 36-pin connector to RST pins of 36 sensors, CN3: connector to DQ, CLK and T H igh pins of sensors and magnet power supply interlock pins, CN4: power supply connector for +5 V and +12 V lines, IC1: Quad 2-Input NOR Gate, IC2: 2 × 4 Decoder M74HC139, IC3, IC4 and IC5: 4 × 16 Decoders CD74HC4514, Q: Transistor, RL: Relay, R: Resistance. (Ref Pal A. M. et al 2014)…”