TEMPERATURE is basically the
measurement of how hot or cold something
is, and it is one of the fundamental entities in
any kind of process control. Temperature is
also a measure of the average kinetic energy
of particles in a system. Adding heat to a
system increases the kinetic energy of its
particles and hence an increase in the
temperature of the system.
Temperature is easily measured using a
thermometer. Nowadays, thermometers come
in all shapes and sizes. In computer-based
automated process control applications, where
it may be required to control the temperature
of a plant, it is necessary to interface the
thermometer to the computer. This is usually
done either by using analogue temperature
sensor devices (such as thermistors,
thermocouples, RTD devices etc) and then
converting the outputs into digital format
using A/D converters, or digital sensors (such
as semiconductor sensor chips) are used with
direct interface to the computer’s.