Design Of Gas Alarm Control System Based On ARM Embedded System

With the development of economy and the improvement of the level of industrialization,many industrial field exist flammable or toxic and harmful gas,the main characteristics of the gas is flammable,explosive,dangerous,toxic and harmful,once the leakage phenomenon,it will seriously threaten the life safety and enterprise safety production.National standards require that these sites must be installed gas alarm systems in order to detect danger in atimely manner and quickly deal with.The thesis designed and implemented an embedded gas alarm control system,which is a bus type gas alarm control system.The system consists of controller and field components,the field component has two kinds of detector and module,the communication mode between the controller and the field component adopts RS485 bus.In the aspect of hardware,the controller and detector were designed and implemented in the thesis.The function of the controller was realized the communication with the field components,the communication with the host computer,and a series of other system functions,including the choice of ARM microcontroller,the design of system power management circuit,power supply management circuit of detector,key indicator lamp circuit,RS485 bus communication circuit and other peripheral circuits.The function of detector was realized the communication with controller,sensor signal acquisition and processing,and other a series of basic functions,including the selection of ARM microcontroller,the design of sensor signal processing circuit,a signal output circuit and peripheral circuit.In the aspect of software,the thesis designed a kind of gas detector which is compatible with many kinds of gas sensors.By replacing the sensor and signal processing circuit,the detector can be used for the detection of different types,different range and different target gas;by adding different addresses,a detector can be installed with several of sensors probe,to realize a detector to detect several kinds of gas.Meanwhile,the thesis designed the controller signal processing software which is compatible with many kinds of gas detectors,which mainly includes RS485 communication module,alarm information judging module,alarm information processing module,GUI module and so on.In the software design,Based on object method was used,the structure of class was realized by using C language,fully considered the structure and modularization,improved software reusability,to facilitate the maintenance and upgrading of the late software.The thesis designed to strictly comply with the requirements of GB 16808-2008"Combustible gas alarm control units" and GB15322.1-2003 "Combustible gas detectors"Part 1:Point type detectors for 0 to 100%LEL combustible gas.In determining the design scheme,the first consideration was to meet the technical requirements of the relevant national standards,meanwhile,to meet the basic functions,to meet the requirements of performance and EMC standards,in the design of carefully consider the overall layout,to take the necessary anti-interference measures.In software testing,black box testing theory and white box testing theory were used.Several testing technique,such as equivalence partition testing,boundary value testing,state transition testing,maximum load test(stress testing),fault tolerance test,and branch condition testing,were used in order to ensure the correctness and reliability of the system software.The embedded gas alarm control system designed in the thesis has a certain degree of scalability,which is designed according to the 128 points of the field components at the beginning of the design,so as to facilitate the expansion of the field application;Meanwhile,GPRS and TCP/IP communication module were also reserved,in order to realize the remote wireless networking and urban fire monitoring network.The embedded gas alarm control system designed in the thesis has entered the phase of small batch in January 2015.The product after a series of hardware and software testing to meet the requirements of the corresponding national standards,to September 2015 passed National Supervision and Test Center For Fire Electronic Product Quality of the type test,at present the product has entered the phase of mass production stage.