global-journal-of-research-in-engineering-f-electrical-electronic Global Journal of Research in Engineering - F: Electrical & Electronic 0975-5861 2249-4596 Global Journals Publishing Group Incorporated 74460 Temperature Control of a Hot Plate Using Microcontroller-Based PWM Technique AkterTabinder BANGLADESH, University of Dhaka 15 03 2012 12 F6 45 48

The temperature of a hotplate used for prebaking, post baking, dehydration baking etc. changes with time. But, in baking purpose the temperature should remain constant. This work concerned with the designing a new and cost-effective microcontroller based PWM temperature controller to control the temperature of a hot plate. PWM controller has been selected because it has faster and accurate response than the conventional on-off controller. Here, the microcontroller senses the zero crossing of the line voltage and generates a pulse for every half-cycle. The width of the pulse is adjusted to change the firing angle of a TRIAC. The TRIAC is interfaced with the microcontroller circuit using an opto-coupler. The temperature of the hot plate can be increased or decreased using two push-button switches. The preset temperature will be saved in EPROM of microcontroller and displayed on an LCD display. The temperature of the hot plate is sensed by a thermocouple and fedback to the microcontroller. The microcontroller keeps the temperature constant by changing the firing angle of the TRIAC. The system has been constructed and tested successfully.

 Microcontroller PWM controller TRIAC EPROM Zero-crossing Temperature Control. Full Text

The temperature of a hotplate used for prebaking, post baking, dehydration baking etc. changes with time. But, in baking purpose the temperature should remain constant. This work concerned with the designing a new and cost-effective microcontroller based PWM temperature controller to control the temperature of a hot plate. PWM controller has been selected because it has faster and accurate response than the conventional on-off controller. Here, the microcontroller senses the zero crossing of the line voltage and generates a pulse for every half-cycle. The width of the pulse is adjusted to change the firing angle of a TRIAC. The TRIAC is interfaced with the microcontroller circuit using an opto-coupler. The temperature of the hot plate can be increased or decreased using two push-button switches. The preset temperature will be saved in EPROM of microcontroller and displayed on an LCD display. The temperature of the hot plate is sensed by a thermocouple and fedback to the microcontroller. The microcontroller keeps the temperature constant by changing the firing angle of the TRIAC. The system has been constructed and tested successfully.