Remote Monitoring System For Air Quality Parameters (machine Design)

This paper elaborates the design method of the lower computer of air quality parameter monitoring system and its software and hardware realization. This system, which works under the remote nobody-watch condition, uses well-rounded MCU technology and takes micro-controller AT89S8252 chip as the primary controller with the expansion of related peripheral circuits and adopting the software design of modulization.The system mainly includes the CPU module, data acquisition module, LCD module, MODEM communication module and program downloading module, etc.The CPU module mainly uses the micro-controller AT89S8252 to consist of the host control device in order to perform the whole system control action.The main function of the data acquisition module is to convert two channels analog inputs into digital signals. The use of the powerful AD7705 transformation chip enables this module to have the filter function which can filter the industrial frequency noise.The main function of the LCD module is to display the result data of A/D converter, which can be easily observed.The main function of the MODEM communication module is to transmit the acquired data to the upper computer by the serial communication of RS-232C.The flexible and convenient ISP programming pattern is adopted in the program downloading module, which can conveniently and quickly download the debugged program to MCU's FLASH program memory, and is also convenient for the system to update on-line.The software of the system is mainly composed of main module, data acquisition module, display module and communication module, etc. The core module of the system is the main module which manages the other three sub-modules. In order to avoid the communication deadlock and other contingencies which lead to break down the lower computer and achieving auto-recovery in the software failure, moreover, a software watch dog module is inserted to monitor the running conditions of the system in the main module and the communication module in suitable sites.The completed system can automatically monitor two analog parameters (include SO₂ and NO₂) in air.