Design On Smart Electric Pneumatic Valve Positioner

As a key attachment to the valve, the valve positioner significantly improves the performance of the valve in many aspects such as measurement precision, speed and flexibility. At present, The hot issue on positioner focus on smart electric pneumatic valve positioner. Some big companies at aboard such as:Siemens, Fisher-Rosemount and so on release a series of product about smart positioner. The design on positioner started a little late at home. The positioner based on the principle of mechanical force balance is generally used at home. Howerver it still has some disadvantages. But the positioner imported from foreign countries is expensive. Therefore the design on smart positioner is exigent in our country.By analyzing the positioner working principle can help me know the design goal. This paper develops and designs a new type of smart positioner based on 32 bite LPC2290 in ARM7. This paper mainly does research on the following aspects:1. By analyzing the structure of hardware of smart positioner products at home and abroad can make me have a definite purpose on hardware design and finish hardware design with LPC2290 at the core. It includes the allocation of hardware resource, the design of power supply circuit, detection circuit for current signal, detection circuit for valve position signal, AD converter circuit, driving circuit for piezo valve, button and display circuit, circuit debugging and driver for the separate hardware circuit is also finished.2. By analyzing the function of smart positioner products at home and abroad can make me have a definite purpose on software design, and finish the design of software for the smart positioner. It includes the design for human-computer interface program, initialization and control algorithm.3. In this paper, an algorithm is proposed after analyzing properties of controlled plant. It is showed from the results of experiment that effectiveness of internal control is proved satisfied. The effectiveness of control by the controller designed in this paper is compared with the effectiveness of control by the controller designed SEPP4000 smart positioner,which shows effectiveness of control by the controller in this paper is more satisfied.