Microcontroller-based design of the boiler
temperature control system
ABSTRACT
According to the market demand and the characteristics of domestic heating, this
paper develops MCU intelligence controller for the minor gas-fired boiler which is
domestic heating equipment on the basis of investigation of heating demand widely. The
research purpose is to change the inconvenience of temperature control bring by using coal
fired boiler for centralized heating, to increase economics of heating.The software called
Protel99se for circuit designed is used to develop the hardware of the controller. The
hardware includes the power supply circuit, the reset circuit,the clock circuit, the alarm
circuit, the LCD display circuit, and the temperature collection which is the core of this
controller. The three-pin integrated-circuit voltage regulator W7800 (7900) series
component 7805 is used for the power supply. The Atmel AT89S51 chip is the core chip of
the controller. The integrated temperature sensor DS18B20 is used to measure water
temperature in boiler. The key circuit is used to set the alerm temperature and analog water
in or out. In addition, LCD is used to display water level bound, current water level,
temperature alerm value by presupposition and current temperature. When water level
beyond its bound or when current temperature beyond its alerm value, the system gives an
alerm and makes boiler burner off. When water temperature is down, the system releases
alerm and makes boiler burener on. The system does it again and again.So the system can
save energy and improve energy utilization rate. Aim at the demand and characteristic of
the system, on the basis of these hardware and implement method, using assemble
language, system designs boiler temperature control system design based on singlechip.
This software includes temperature and water level monitor main program, temperature
collection subprogram, analoy water in and out subprogram, keyboard scan subprogram,
LCD display subprogram etc. Use practicality to validate system’s dependability and
stability, and the system can operate successfully.
Keywords:MCU; Liquid Crystal Display; Gas boiler; Temperature control;DS18B20
