| With the continuous expansion of potash fertilizer production scale, increasing number of control devices and evolving of field technology, the requirements of integrative producing control are proposed. In this paper, Based on the background of the Qinghai Salt Lake One million tons of potash production control system, and according to the requirement of the control system, this thesis design a suit of control system based on three layer networks of NetLinx.At first, the fieldbus and fieldbus control system is recapitulative introduced, with the emphasis on Rockwell Automation’s NetLinx three layer networks, namely the structure and technical characters of DeviceNet, ControlNet and Ethernet/IP. Then according to the process control requirements, integrative potash fertilizer production control system is designed based on the framework of NetLinx three layer networks. In this part, the software and hardware platform configuration is introduced. In order to improve the reliability of control system, dual CPU redundancy system and optical fiber ring redundancy network is designed, as well as the grounding and power supply application. Applying HMI software FactoryTalk View SE designed and drawn up the supervisory system. In next part, for the purpose of controlling one of the most important controlled variable which is the level of the Flotation machine, PID algorithm is applied. In order to improve the adaptability of the controller, generalized predictive algorithm is applied to control level of the flotation machine. The algorithm is simulated on Matlab and the result is analyzed. In the last part, combining the project actual situation summarized the system debugging step and problems encountered.Proved by system running, system can complete the production process monitoring and alarm, and provide real-time trend display, with high reliability, good stability, precise control and the ability to develop strong upgrading. |
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