Research On The Intelligence Controls System Of The Valve Positioner On Regulating Valve

Mechanism, electronics, communication, the knowledge of the control theory and the knowledge of relative software are applied in intelligent valve positioner, so it is a intelligent product of muti-subject. The main object researched by this thesis is control system of Single Chip Microcomputer. It send out signal to control piezoelectricity valve after collecting the designed signal of the valve position from the adjustor and the real signal of the valve position from feedback,and fuzzily dealing with this two signals,So that it can control the quantity of gas which is injected into the gas chamber in the control valve. Which make the valve stem work and make it attain accurate position. Comparing with traditional valve positioner, the intelligent valve positioner has the advantages of excellent controlling accuracy, low energy consumption and more functions, and it meet the demand of process control with its function of thinking and possessing some experience and knowledge of man.This research has mainly accomplished the content as followings:(1)Learn deeply about the configuration and working principle of traditional valve positioner, analyse the main disadvantages of traditional valve positional and learn about the developing situation of the foreign intelligent valve positioner.(2) Design wholly the control system of the intelligent valve positioner; choose the right chip which is in the control system.(3)As formcontrolling strategy of the system, the fuzzy control is applied in this system.So it is not necessary to be built the whole and accurate mathematic model for the system, and the system can make a decision according to people's experience and knowledge.At the same time, the system possesses good robustness and self-diagnose function.(4)Make I/V transform for the current signal of 4-20mA coming from adjustor, then make A/D transform for the signal received just now. Make A/D transform for the signal delegating valve position, which is feed, backed from thepotentiometer.(5) Design and manufacture the back passage of the system, which make Single Chip Microcomputer send out faint controlling signal to control the on/off of piezoelectricity valve through Solid State Relay. As a result, it can control the quantity of gas which is injected into the gas chamber in the control valve.(6)Design and manufacture the key and showing circuit of the system.(7)Design the function of protecting data when no power, which can protect the important data when power, is off, and send the protected data into the Single Chip Microcomputer when the power is on.(8) Make a transform from TTL signal sent out from the Single Chip Microcomputer to RS-232,which can make the control system of Single Chip Microcomputer with PC.(9) Design and manufacture the replacing and warning circuit.(10) Compile the program for the whole control system, which realize all kinds of functions and the controlling strategy of the control system.The software of the control system of Single Chip Microcomputer is written with Assembly Language, the form of the data in the software is the form of the fixed point data. The program of series communication of PC is developed with VB6.0 and the data is transferred through MSComm communication control.