| As the characters of wastewater treatment process is nonlinear and multivariable, traditional control strategies in wastewater treatment plant have used traditional meters and manual control model. Moreover the whole control process has been dependent on people's knowledge and experiences, which means unstable water's quality, low labor productivity and decentralized system information.Considering the actual control requirement in a sewage work, this paper compares and analyzes several industry network patterns in a integrated automatic system's integrality,reliability, extendibility and open capability, and brings forward a communication network scheme, which is based on PROFIBUS field bus.It also offers the network's constituent parts, the steps of setting the network, and the main parts of communication program.There are many difficulties in a aeration tank control, such as intermittence,non-linearity, delay,and the direct control variable is hard to be online measured. This paper compares the results of respectively applying PID FUZZY strategy using of MATLAB emulation toolbox. The fuzzy strategy gets a good result, and it needn't a correct model, so it is chose and implemented by a table look-up program. Because PID is simple,convenient to use, and it's the most basic way in industry process control,a new idea is suggested that combining PID and FUZZY, making the control variables of PID be online self-setting.In view of the high-power equipments, the local control station's designs adopt frequency changer and soft motor starter to save energy and protect equipments... |
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