| With the mankind’s increasing awareness of environmental protection, human beings pay more attention to the monitoring of the water quality, including surface water and industrial waste water. Our governments is making more efforts to the Water pollution control work and take more and more higher requirements about the work of the water environmental monitoring. Due to getting water quality information has the characteristics of strong timeliness, especially water quality preparing forecast demands collect and transfer monitoring information rapidly and accurately.The conventional surface water monitoring method can’t meet the needs of real-time collect and transfer water quality information rapidly and accurately.Therefore,the automation and network of water quality monitoring development is imperative.This article applies the embedded system and GPRS wireless communication technology to the COD monitoring of surface water on the base of the analyzes that the development of COD monitoring system at home and abroad. The age of things networking has come and the application of embedded system and GPRS wireless communication technology is a very good solution to the requirements of the water monitoring quality.The surface water COD monitoring system has five components that mainly includes the COD monitoring equipment hardware selection and development, embedded development platform, GPRS/WIFI wireless communication design, software design and experimental data analysis. This system mainly uses the ARM chip and the Linux system as the control platform for ground water to realize the function of automatic sampling and dose resolution calibration. GPRS/WIFI wireless communication part through the wireless transmission functions of TCP/IP agreement to remote data sending. As terminal morniting platform, it uses the VC++development to realize the remote monitoring function and field through the Android software development of touch screen realize the monitoring equipment commissioning and monitoring. Terminal monitoring platform developed by VC++to realize remote monitoring function and debugging and monitoring of the field equipment function through the Androids software development of touch screen.First, through the analysis of domestic and foreign present water quality monitoring method and the monitoring equipment of water quality, this paper adopts the sealed catalytic digestion-spectrophotometers as the detection method for surface water COD monitoring system, and the method has higher consistency for the measured results of the surface water with standard method.Secondly, based on the determination of detection method, this paper designs the surface water COD online automatic monitor hardware system. It includes the control system, metering system and digestion system. For control system, it considers not only the realization of the automatic control process but also consider the realization of the network work. This paper designs the ARM chip as the core of the control system by the consideration of the function requirement of COD monitoring system. With fully considering the system requirement and accurately sampling, we design the peristaltic pump sampling combined with photoelectric doses of automatic dosage system. For the digestion system design, we mainly design of the PID temperature control and photoelectric detection of COD parameters.Again, the function of software design mainly includes the construction of embedded Linux operating system platform and realizes the GPRS wireless monitoring terminal. Constructing embedded Linux operating system platform, the first to transplant Boot Loader program in customized hardware platform; Configuration compile and transplant Linux system kernel; establish Cramfs file system; to realize the development and transplanted the serial driver I/O driver PWM driver A/D driver. Next, design remote monitoring terminal software, realizes to surface water COD monitoring equipment remote real-time monitoring and touch screen to realize monitoring equipment commissioning and monitoring. Secondly, we design remote monitoring terminal software to achieve the remote real-time monitoring of COD monitoring equipment for the surface water and touch screen to realize debugging and monitoring for the monitoring of equipment at the scene.Finally, this paper introduces the GPRS message alarm function, the controller output PWM testing experiment and COD value calibration test method. And to have the basic error measurement and repeatability error measurement for the experimental data of COD monitoring instrument, the measurement results of the basic error is less than7%, repeatability error is less than6%.The results show that the instrument can be used for the COD on-line monitoring, system operation is stable and reliable, The system is in line with the chemical oxygen demand (COD) meter test technical requirements. |
PDF Full Text Request