The Network Alarm System' Achievement Which Is Based On The 485 Bus

This paper introduces a design and implementation of an intelligent alarm system which can send information through network. It describes the whole structure of the system and the programme of circuit design. In the actual design of system, considering from the reliability, practicality and economy, we realize the control for the system with STC89C516RD+ as the main CPU, and achieve the expansion of bus through RS-485, and realize the distance communications and dial-up alarm through telephone network. Furthermore, the system can connect with PC and realize PC management.The network alarm system can achieve a variety of linkage output through bus extension modules. It can be used for lighting,video,electronic maps and other forms of linkage demand. The main theory follows as:if various front-end alarm controllers detect the alarm information,which would be sent to the alarm control host .The host through the establishment of procedures in advance analyses and affirms the alarm signal whether need alarm at the scene and dial-up alarm,whether need through CID agreement report information to alarm center ,whether need linkage related output devices. The alarm controll host owns the large-capacity flash memory, and can be used to store various types of operating records and alarm information, all of these information will not lose when the controller power-down. User can inquire related information conveniently through LCD keyboard.The entire system is used low-power design, in order to ensure stability of the system,we increase anti-jamming measures in software and hardware aspects. The system has got verified that it could expand alarm modules through the RS-485 bus,could carry out the long-distance control,could monitor the various prevention district effetively and make real-time processing, could dial-up alarm automatically and transmit the alarm information to long-distance,could store all kinds of effective information and support wireless control, could meet the basically needs of different users.Besides,in order to achieve practical requirements,system makes a corresponding improvement about the cubage and cost. It is very suitable for the modern district fire prevention,security,anti-gas leak,and so intelligent monitoring sites.