The Design Of Fire Alarm System For Smoke And Heat Based On Two-Bus

With the continuous progress of science and technology,human's living standards are constantly improving,and people's travel frequency increased year by year.With so many merits such as convenient,safe and fast,high-speed train become the prefer travel tool gradually,and plays a positive role in the stable operation of national economy.As an important part of the safety for traffic protection,the fire alarm system has the characteristics of "early detection,early warning and early rescue",which greatly reduces the passenger casualties and economic losses caused by the spread of fire.The fire alarm system imported from abroad has problems such as too expensive or could not maintain in time.In order to solve these matters,the article combines the actual environment of the high-speed train with the application characteristics of the fire alarm system,introduces the two-bus technology into the system for connection and communication,and designs a smoke and heat compound fire alarm system based on low-cost and low-power.According to the detection principle of smoke particles and ambient heat at the time of fire occurred,this paper designs the corresponding smoke and heat sensing circuit with infrared tube and thermistor which are in low-power and low-cost,and does some analysis and logic control based on Microchip's PIC16F716 microprocessor to achieve the central processing.In order to ensure the accuracy of fire judgment,we use the "floating threshold method" is used to deal with the smoke detection,and realize the heat signal processing by combining the "rate of change detection method" and "difference detection method".According to the system requirements which are to achieve the sound and light alarm,liquid crystal display and other functions,we designs fire alarm controller which consists of power board,mother board and display board.Taking the Winbond's W78E516 B microprocessor as the core to achieve the central processing,and the two-bus communication method is adopt to divide the fire detection signal into smoke warning,heat warning and smoke heat compound fire alarming,so that it can realize the multi-level monitoring of fire alarm in final.In addition,the alarm controller plays a role of electronic encoder in the form of keyboard,so we can achieve the goal of encoding for the smoke and heat detector.This paper also develop the fire monitoring software by using C# technology to achieve the real-time display for alarm controller signal through the 485-USB way,storing the time and the location of fire or fault occurred for inquire.The functionality of the fire alarm system has been improved.Finally,we summarize the design results of this paper,and do some reliability analysis for the smoke and heat compound fire alarm system based on the two-bus to achieve all the functions of the design goals,and realize the design requirements of the cooperative company.