5. INDUSTRIAL TEMPERATURE CONTROLLER

Temperature controllers are used in most of the manufacturing industries. The industries like textile mill, pharmaceutical industry, oil refinery etc. all requires temperature controller. The temperature controllers are used to maintain constant temperature of process or plant or any material. In such temperature controller system there is one reference temperature called set point or set temperature that is the desired temperature that must be maintained. This reference temperature is set by external means. In addition, it can be always adjustable according to requirements. Once this temperature is set the system tries to maintain it by sensing the current temperature and controlling it using heater, cooler or compressor etc. It senses current temperature, compares it with reference temperature and generates error signal. Then based on this error signal it controls heating elem ent (or cooling element). If set temperature is more than error signal is negative and vice versa. Most popular type is the microcontroller based temperature control system. It controls the temperature of any device according to its requirement for any ind ustrial application. This report aims at controlling the temperature of a composting process, which is being heated by a 50 -watt heating element. For controlling the temperature of the heating coil, the current through the heating element is controlled. The thermal energy produced by the heater is directly proportional to the square of the current passing through the heater coil.Hence, by controlling the currentthrough the heater coil, the heat produced by the heater is controlled. The target is to control the temperature ofthe plate between room temperature and 100 °Cwith the optimal control range being from 50°C to 70°C. Following this significance of temperature control in processes to used different types of temperature controller for composting machine.