The Research And Development Of Smart Valve Positioner Based On FPGA

In the field of industry, regulator is common used in regulating of pipe flow.The deviation of valve opening between the actual value and the setting may exert an influence on the operation of downstream piping and equipment. The control accuracy of regulator is high or low, and response speed is determined by the valve positioner control system. Positioner is very important for regulating valve control function, studies its key technology can improve the control precision of regulating valve, and reduce the errors rate, so the study of the control system of valve positioner is very necessary.The process of research and development about a kind of smart valve positioner is elaborated in this paper.This smart valve positioner with HART communication function is designed based on the FPGA. The single HART communication module uses AD421 and HT2015 to build, to communicate with the host computer, receiving data frame and sending the response frame. Double feedback circuit is designed, which is composed of the valve position sensor and valve pressure sonsor.The design is for the accuracy of the valve of the current data, and providing sufficient information for input control algorithm. About the control algorithm, the fuzzy PID controller is designed,which is combination of intelligent control strategy and PID. In this field,three step response curve is obtained, by comparison, the fuzzy PID algorithm is approprite to improve the performance of the control system the valve positioned. In the field of program software design, The FPGA program development environment Quartus II and Modelsim simulation environment is used.Compared with the valve positioner on the market, the designed system has higher control accuracy, faster response speed and stronger anti-interference ability.The design of double feedback circuit can ensuree the accuracy of the feedback data. HART communication circuit commits good communications from slave unit to the upper monitor. By the good human-computer interaction platform, the operator enables to monitor the current related data of the valve directly.All in all, the design of the control system of the valve positioner can conform to the control requirements, can meet the requirement in the different applications of the valve position control.