The Develop Of Wireless Smoke Alarm System For Existing Passenger Trains

Having analyzed the present state of installing smoke detection and fire alarm devices on passenger trains in our country, this article proposed the necessity of equipping smoke alarm unit on existing passenger cars. Because of the difficulty of wire layout and communication on existing passenger cars, it is not easy to apply widely the wired smoke alarm system, so that it is necessary to develop a newly wireless smoke alarm system for existing passenger trains.According to passenger train's characteristics, photoelectric sensor and scattering smog detection room are deployed on the key spots of fire prevention such as train attendant room and transformer vault, to carry on the examination of the smog density.In order to realize the local warning function, warning extension telephone is established in the train attendant room, to carry on the analysis of the detector signal, send out the acousto-optic warning when having exceptions.In order to realize the central monitoring at a different place, all extension telephones have the wireless signal emitting function. At the same time on each train is established a main warning unit, responsible for receiving signals from each warning extension telephone', carrying on the centralized monitoring and fault warning. The main unit also has the information storage and inquiry functions.To solve the problem of wiring and communication on existing passenger train, wireless signal is transmitted between the main unit and the extension telephones.In order to reduce interference of the smog alarm systems among trains, the extension telephones and main unit addresses are managed, the extension telephone taking passenger car number as its address code and the main unit only recording and warning fault alarms sent out by extension telephones of the same train, largely reduced the false warnings.In order to set extension telephone's address code conveniently and download main unit data, handheld passenger car number editor has been designed, used to realize the function of passenger car number establishment of warning extension telephones, simultaneously the function of main unit data download and data upload from the PC terminal.In order to minimize wire layout and provide convenience to field installation and usage, the system uses the high performance lithium battery power supplied completely by its own, and applies dormancy design in the software, lengthened the battery life of usage.Under the overall project system design, in view of the fact that the system is divided clearly by each function, has few varying parameters, AVR series monolithic integrated circuit is selected to work as MCU, functions modularly to carry on the smog detection, the warning extension telephone, the warning main unit and the handheld passenger car number revision. Various functional modules are designed for hardware circuit and the embedded software. The software uses the C language to develop, which is easily modulated, has the good readability.In view of the problem of considerable interference and the problem of strong vibration on the train, this system has detailed analysis and design in reliability. On the hardware aspect, suitable devices are used, for example, the input/output electro-optic isolation, the relay isolation, decouple electric capacitor deployed for the IC component, and PCB board wiring according to the reliability and the signal completeness principle, suppressed the system's outside disturbance.On the software aspect, passive form anti-interference technology is used at the price of the MCU processing resource, depending upon monolithic integrated circuit software process to realize the anti-interference goal.In the manufacture and install technique, the extension telephone, main engine and the vehicle number editor uses the metallic shielding outer cover to prevent effectively exterior electromagnetic interference which may sneak into the system, largely enhanced the system equipment's resistance to interference;The equipment large-scale components such as internal battery, uses the sea collodion to fix, reduces effectively the destruction of the mechanical shock;The sensor signal wires are held by trunking installation, enhanced its security;The system equipment connector parts easy to receive the mechanical vibrations and fail, are smudged with silica gel to perform reliably when installing.These measures have guaranteed system's reliability.After the system prototype manufacture completed, various functional module accent test has been completed under the laboratory environment, and online test has been carried out for passenger train under actual operating condition,Results indicated that this project researches and develops the wireless smog alarm system to fulfill the passenger train requirement of forewarns regarding the fire prevention, easy to operate and stable to performance.