Microcontroller Based Temperature Monitoring and Closed Loop Control to Study the Reaction of Controlled Variable with Respect to Load Changes

The objective of the present paper is designing 8051 microcontroller based temperature control system to study the reaction of controlled variable with respect to load changes. The process temperature under control is measured using RTD. Then using a microcontroller and suitable software, this instantaneous value of temperature is compared with the desired temperature. The resulting error has been used by the microcontroller to control the firing angle of a TRIAC for controlling the power applied to the heater. The trigger pulse for the TRIAC is delayed by the microcontroller to provide the required voltage to be fed to the heater to get the desired temperature. Thus a continuous closed loop temperature monitoring and control has been achieved. The proportional control scheme has been described in the present paper. The behavior of the process temperature has been studied with respect to load changes. Experimental results have been presented to study the reaction of controlled variable or process temperature with respect to load changes