Design And Implementation Of Oil-Sewage Disposal Automation System Based On PLC

The thesis analyzes and evaluates the configuration of automatic instruments used in sewage disposal procedures. According to current sewage disposal procedure in oil field, a kind of sewage disposal automation system of high degree of integration is researched and designed.A detailed investigation into various solutions of sewage disposal automation system has been carried out. The defects and merits of them are summarized. After that, a solution based on PLC has been chosen. In order to obtain an accurate system model, this thesis describes the status of WangYi sewage disposal station in JiangHan oil field and analyzes every process of the system. Based on this system model, a layered solution is finally adopted. Then combining the analysis of the requirements, a schedule of PLC software module and control objective has been given. In this thesis, the characteristics of SIMENS PLC and WinCC have been covered carefully and then a method introducing variable defined in STEP7 into WinCC environment improves the efficiency in the process of development. To enhance control ability and accuracy, the filter algorithms are adopted by PLC when gathering analog data and implementing the PID algorithm in frequency conversion control. As for the adding drug and filtering subsystems which are the most complicated subsystems and influence the quality of water most, a useful solution is given.The system designed in the way described in this thesis has a reasonable structure, comprehensive functions and a reliable performance.