Research On Water Meter Automatic Calibration Device And Management Information System

With the lack of the water source, the accurate metering of tap water is more and more important. The Tap Water Meter Calibration Station plays an important role in the respect of accurate calibration. But its efficiency and calibration precision is low because of the manual work, like the value of water meter recording, the data processing, and error calculation, etc. Furthermore the history data is saved in paper so that too much time for index is wasted. Meanwhile the data and its statistic and analysis report can't be provided for the superior and customers in time. Thus it is necessary to develop a new automatic calibration device and a management information system, which can help the station keeping ahead among the same field. The design system given in this dissertation mainly aims to solve these issues mentioned above. The main contents are as follows:(1) A management information system is developed. This system has touched almost all business management, eight subsystems in all, such as calibration business, human resource and labor, data statistic and analysis and so on. It is developed with the method of the combination of structural method and oriented object. According to the design steps of the software engineering, requirement analysis, software and database design, and code program are done. Meanwhile function modules can be abstracted using the semi-dynamic software programming system, which can encapsulate some codes with similar function and reduce the size of code.(2) The device of the calibration station is studied. The device uses two highly precise electromagnetic flow meters as the standard meter, and two motor regulated valves are equipped to control the flow. The recording value of the water meter is inputted to the computer by a hand keyboard. The device benefits the calibration work by changing manual operation to the computer auto-control.(3) A computer control system is designed here. PC equipped with I/O cards, including counter card, D/A card and digital output card drives the valve to work and samples data by programming. The system uses one computer to control two water meter calibration pipelines, which can economizes half cost of the hardware. The principle of the finite state machine is applied in the advanced software programming so that the two pipelines can run asynchronously and work efficiency is improved.