Development Of One Flame Monitor System Based On CAN Bus

With the fast progress of the national construction,the requirements of industry and agriculture for electric power supply will increase continually. So far,the thermal power capacity occupies 75% of the nation total power supply. By predicting that the thermal power with coal will still be the main part of our country's electric power supply during a quite long period. The boiler furnace should be burning steady flames in power factory. Otherwise it will decrease the flame burning efficiency, even cause the flame blowout or boiler explosion under unsteady burning conditions. So it is necessary to monitor the flame burning states. In this thesis, one kind of the flame monitoring system was developed which accompanying with CAN bus communication to monitor the flame status in the furnace.First the author introduces the design of the flame monitoring system based on PIC16F877 MCU in details. The detector, (ECADATA company's production), Si-photodiode , is used as the sensor. Its photoelectric current output is proportional to input light's energy. The gasoline flame radiation intensity and flicker frequency are both monitored to improve the system reliability. Thus it is trusted"flame on"only under the case when the radiation intensity and flicker frequency are both above the threshold values; otherwise it is treated as"flame blowout".Then the transmitter, the displayer and the software also are present. In the part of the transmitter, the pre-amplifier logarithmic amplifier, temperature complement circuit, anti-disturbing circuit, and V/I circuit, are discussed. The transmitter outputs 4-20mA . In the part of the displayer hardware design, the I/V convert circuit and the flame intensity signal processing circuit are introduced. The displayer based on PIC16F877 MCU, expanded the CAN communication circuit, the keyboard and the LED. In the part of the software design, the intensity signal processing algorithm, the frequency signal processing algorithm and the keyboard program are conducted.The characters of the flame monitoring system are that, both flame intensity and frequency are measured fast and reliable, the intensity value, the frequency...