CN202708299U - Electromagnetic valve type valve positioner - Google Patents

Abstract

The utility model relates to an electromagnetic valve type valve positioner. The electromagnetic valve type valve positioner comprises an air suction electromagnetic valve, an air bleeding electromagnetic valve, a position sensor, a power source module, a signal conditioning module, an A/D (Analog to Digital) module, an electromagnetic valve driving module, an electromagnetic valve isolation module, an ARM chip, a liquid crystal display module, a keyboard module and a D/A (Digital to Analog) module; the position sensor, the signal conditioning module and the A/D module are sequentially connected; the A/D module and the D/A module are connected into the ARM chip through the electromagnetic valve isolation module; the air suction electromagnetic valve and the air bleeding electromagnetic valve are connected into the ARM chip through the electromagnetic valve driving module; and the electromagnetic valve type valve positioner has the advantages of calculating the optimum control parameter of a valve rod at each position by using a fuzzy control method in the process of controlling a valve rod to move according to a differential value between a set value and a feedback value, thereby solving the nonlinear and overshoot problem of an executing mechanism and achieving the purpose of accurate control and reduction of artificial and environment interference.

Description

A kind of electromagnetic valve type valve positioner

Technical field

The utility model relates to the pneumatic control valve field, relates in particular to a kind of intelligent electric valve positioner.

Background technique

In process control system and other automatic systems, pneumatic control valve has that governing speed is fast, degree of regulation is high, explosion-proof, can be adapted to the abominable characteristics such as industrial environment, therefore in the industries such as medicine, chemical industry, nuclear energy, electric power, get a lot of applications.The topmost core component of pneumatic control valve is exactly valve positioner matching used with it.Valve positioner is controlled the stroke of valve by regulating the pressurized air in the inlet and outlet actuating mechanism for pneumatic control valve.Valve positioner is determining degree of regulation and the speed of pneumatic control valve.Therefore valve positioner has very important effect for pneumatic control valve.Valve positioner mainly is (such as 4-20mA by the control signal accepting to set from other controllers or user, 0-10V etc.), compare with the collection signal of position transducer, then according to the algorithm of design the pneumatic signal that enters actuator is controlled, thereby change the aperture of valve, the flowing of the medium that the control pneumatic control valve is regulated.

Up to the present, on structure and controlling method, the development experience of valve positioner the different stages, can be divided into: several stages such as nozzle flapper equilibrium of forces, coil manipulation equilibrium of forces, electrical valve location.Initial nozzle flapper equilibrium of forces and coil manipulation equilibrium of forces all are to adopt in a large number such as mechanical parts such as Regulation spring, screw, cams, are using and the debug process shortcoming such as occur easily wearing and tearing, influence of vibration is large.Electropneumatic valve positioner then adopts mechanical part and movable member seldom, has reduced the impact of wearing and tearing and vibration.The present main Pneumatic component of electropneumatic valve positioner has three kinds: piezo electric valve formula, nozzle baffle type and electromagnetic valve type.Piezo electric valve has the characteristics such as power consumption is little, but at present the cost of piezo electric valve is high, manufacturer is few and also higher to the requirement of source of the gas.The nozzle baffle type technology maturation, but machinery is given a shock easily.Then cost is low comparatively speaking, producer is numerous for solenoid valve, and technology is also ripe with respect to piezo electric valve, has the characteristics such as low cost, high stability, so the utility model adopts solenoid valve as the Pneumatic component of electropneumatic valve positioner.

On Chinese market, the foreign brand name that is used for the intelligent valve positioner of control valve has occupied most domestic market.Main foreign brand name has: the DVC 6000/DVC2000 of Ai Mosheng-Fei Xier (Emerson-Fisher), the SIPART PS2 of Siemens (Siemens), ABB-H﹠amp; The TZIDC of B, the SVP 3000 of the military Yamatake in mountain etc.Siemens SIPART PS2 adopts piezo electric valve, and what Fisher, ABB and mountain force were then adopted is nozzle-type.Adopt the external product of nozzle-type to wait impact in order to reduce vibrations, therefore increased a large amount of costs in Machine Design.

When adopting solenoid valve and other Pneumatic components that the stroke of valve is controlled, at present a lot of pneumatic positioner valves adopt the shoulder rotation control of five steps, namely when error amount is large, adopt Bang-Bang control, when error amount hour adopt PID control, when error amount is little in the valve position of dead band, then be failure to actuate.But because pneumatic actuator exists obvious nonlinear characteristics, and the impact of other external environment conditions such as the pressure of source of the gas, load variations, traditional PID controlling method causes over control easily.Therefore the utility model has carried out following improvement to it: in the process of control stem movement, difference according to setting value and value of feedback, adopt fuzzy PWM controlling method, utilize FUZZY ALGORITHMS FOR CONTROL to calculate the optimization control parameter of each position of valve rod, thereby solve the non-linear and overshoot problem of actuator.

Summary of the invention

The purpose of this utility model is for the deficiencies in the prior art, and a kind of electromagnetic valve type valve positioner is provided.

The purpose of this utility model is achieved through the following technical solutions: a kind of electromagnetic valve type valve positioner, and it comprises air inlet electromagnetic valve, pressure-releasing electromagnetic valve, position transducer, power module, signal condition module, A/D module, 2 solenoid valve driving modules, 2 electromagnetic isolation modules, ARM chip, LCD MODULE, Keysheet module and D/A modules; Wherein, outside direct current 24V power supply converts the backward ARM chip power supply of 3.3V to by power module; Position transducer, signal condition module and A/D module link to each other successively, and the A/D module is by the A/D interface of an electromagnetic isolation module access ARM chip; The D/A module is by the D/A interface of another electromagnetic isolation module access ARM chip; Air inlet electromagnetic valve is by the PWM interface of a solenoid valve driving module access ARM chip, and pressure-releasing electromagnetic valve is by the PWM interface of another solenoid valve driving module access ARM chip; Keysheet module is by keystroke interface access ARM chip; LCD MODULE is by LCD interface access ARM chip.

The beneficial effects of the utility model are:

1, adopts solenoid valve as the Pneumatic component of valve electropneumatic positioner, have vibration proof, be quick on the draw, easy for installation, lower-price characteristic.Can satisfy the requirements of domestic valve electropneumatic positioner.

2, adopt fuzzy PWM controlling method to carry out closed loop control, in the closed loop control algorithm flow process, utilize five traditional step shoulder rotations, adopt fuzzy algorithmic approach to calculate the optimum dutycycle of PWM that this moment, solenoid valve adopted, utilize FUZZY ALGORITHMS FOR CONTROL to calculate the optimization control parameter of each position of valve rod, solved the overshoot of five step of tradition shoulder rotations and the nonlinear characteristics of actuator, thereby obtained that overshoot is few, the control characteristic of fast response time.

3, according to adopt the characteristics of fuzzy PWM controlling method and actuator's operation, designed full automatic parameter tuning method so that the smoothness that valve positioner can move under various occasions, control accurately, reduce the interference of artificial and environment.

Description of drawings

Fig. 1 is the structured flowchart of the valve positioner of electromagnetic valve type;

Fig. 2 is the working procedure schematic representation of the valve positioner of electromagnetic valve type.

Fig. 3 is fuzzy PWM control schematic representation;

Fig. 4 is that best PWM dutycycle is calculated schematic representation.

Embodiment

As shown in Figure 1.The utility model electromagnetic valve type valve positioner comprises air inlet electromagnetic valve, pressure-releasing electromagnetic valve, position transducer, power module, signal condition module, A/D module, 2 solenoid valve driving modules, two electromagnetic isolation modules, ARM chip, LCD MODULE, Keysheet module and D/A modules.Wherein, outside direct current 24V power supply converts the backward ARM chip power supply of 3.3V to by power module; Position transducer, signal condition module and A/D module link to each other successively, and the A/D module is by the A/D interface of an electromagnetic isolation module access ARM chip; The D/A module is by the D/A interface of another electromagnetic isolation module access ARM chip; Air inlet electromagnetic valve is by the PWM interface of a solenoid valve driving module access ARM chip, and pressure-releasing electromagnetic valve is by the PWM interface of another solenoid valve driving module access ARM chip; Keysheet module is by keystroke interface access ARM chip; LCD MODULE is by LCD interface access ARM chip.

As shown in Figure 2, the working procedure of the utility model electromagnetic valve type valve positioner is as follows: outside input 4-20mA electric current, 0-20mA electric current, 0-5V or 0-10V are as control signal, after carrying out I/V conversion, amplification filtering by the signal condition module, sample and change by the A/D module, import the ARM chip by the electromagnetic isolation module into the SPI communication modes; Position transducer gathers the valve position feedback signal, carry out amplification filtering through the signal condition module after, sample and change by another passage of A/D module, import the ARM chip by the electromagnetic isolation module into the SPI communication modes; Setting value and value of feedback are processed in the ARM chip, utilized fuzzy PWM controlling method, obtain the needed optimum dutyfactor value of electromagnetic valve, utilize solenoid valve driving module, the time of the Push And Release of control air inlet electromagnetic valve and pressure-releasing electromagnetic valve.Simultaneously, with the SPI communication modes, the actual value with valve location in the D/A module converts 4-20mA to by the electromagnetic isolation module, for other devices.LCD MODULE shows the information such as position of valve, and operator carry out every setting by Keysheet module to positioning work piece.

In the utility model, air inlet electromagnetic valve, pressure-releasing electromagnetic valve, position transducer, power module, signal condition module, A/D module, 2 solenoid valve driving modules, two electromagnetic isolation modules, ARM chip, LCD MODULE, Keysheet module and D/A modules are related domain electronic device commonly used, and the utility model is not construed as limiting the concrete structure of each assembly.

As shown in Figure 3, the fuzzy PWM controlling method of the employing of the valve positioner of the utility model electromagnetic valve type is carried out closed loop control to the valve positioner of electromagnetic valve type, specific as follows: as at first to detect the setting value of valve positioner of electromagnetic valve type and the value of feedback of valve actual displacement, calculate again the error e Pos between setting value and the value of feedback; Then the absolute value of error in judgement ePos | the ePos| size, if Error Absolute Value more than or equal to the separation z1 of Bang-Bang control with the PWM periodic control, then according to the direction of the positive and negative and stroke of error, is carried out Bang-Bang control to solenoid valve; If Error Absolute Value | ePos| is greater than dead zone range z2 and less than the separation z1 of Bang-Bang control with the PWM periodic control, the deviation of the position when moving according to valve rod so and the variance ratio of deviation, adopt the fuzzy PWM controlling method of simplifying to draw the optimum dutycycle Duty of PWM that this moment, solenoid valve adopted, it is the PWM control of Duty that solenoid valve is adopted dutycycle; If Error Absolute Value | ePos| is less than or equal to dead zone range z2, represents that so valve rod moves in the dead zone range, and the electromagnetic valve switch state remains unchanged.

Wherein, the fuzzy PWM controlling method of simplification is to determine optimum dutycycle according to the position of valve rod operation by blur method, as shown in Figure 4, may further comprise the steps.

The first step: at first calculate the deviation ePos of valve physical location Pos and desired location sPos, and the variance ratio dPos of deviation.Wherein ePos and dPos calculate gained according to digital quantity 0-4095 and 0-2000 respectively, so the domain interval is respectively [0,4095] and [0,2000], it are done accordingly being converted into according to following formula:

$\mathrm{ePos}1=\frac{12}{4095}\×(\mathrm{ePos}-\frac{4095}{2}),$

$\mathrm{dPos}1=\frac{8}{2000}\×(\mathrm{dPos}-\frac{2000}{2}),$

The domain E that gets ePos1 is [6 ,-5 ,-4 ,-3 ,-2,1,0,1,2,3,4,5,6], and the domain D of dPos1 is [4 ,-3 ,-2 ,-1,0,1,2,3,4].

Wherein, the quantizing rule of ePos1 adopts as follows:

1) when-6≤ePos1＜-5, gets E=-6;

2) when-5≤ePos1＜-4, get E=-5;

3) when-4≤ePos1＜-3, get E=-4;

4) when-3≤ePos1＜-2, get E=-3;

5) when-2≤ePos1＜-1, get E=-2;

6) when-1≤ePos1＜0, get E=-1;

7) when 0≤ePos1＜1, get E=0;

8) when 1≤ePos1＜2, get E=1;

9) when 2≤ePos1＜3, get E=2;

10) when 3≤ePos1＜4, get E=3;

11) when 4≤ePos1＜5, get E=4;

12) when 5≤ePos1＜6, get E=5;

13) when ePos1=6, get E=6.

The quantizing rule of dPos1 is as follows:

1) when-4≤dPos1＜-3, gets D=-4;

2) when-3≤dPos1＜-2, get D=-3;

3) when-2≤dPos1＜-1, get D=-2;

4) when-1≤dPos1＜0, get D=-1;

5) when 0≤dPos1＜1, get D=0;

6) when 1≤dPos1＜2, get D=1;

7) when 2≤dPos1＜3, get D=2;

8) when 3≤dPos1＜4, get D=3;

9) when dPos1=4, get D=4.

Second step: the domain of getting output variable PWM is taken as: P=[-4 ,-3 ,-2 ,-1,0,1,2,3,4], set up fuzzy control rule table (as shown in table 1), when working control, as long as by input quantity is quantized and two steps of tabling look-up, just can obtain optimum taking air ratio P.

Table 1: fuzzy control rule table

In the table, E is the value of ePos1, and D is the value of dPos1, and P is optimum taking air ratio.

The 3rd step: the exact value Duty of the optimum taking air ratio P of output:

$\mathrm{Duty}=\frac{(1-0.1)\×P}{8}+\frac{1+0.1}{2}.$

Claims (1)

1. electromagnetic valve type valve positioner, it is characterized in that it comprises air inlet electromagnetic valve, pressure-releasing electromagnetic valve, position transducer, power module, signal condition module, A/D module, 2 solenoid valve driving modules, two electromagnetic isolation modules, ARM chip, LCD MODULE, Keysheet module and D/A modules; Wherein, described outside direct current 24V power supply converts the backward ARM chip power supply of 3.3V to by power module; Position transducer, signal condition module and A/D module link to each other successively, and the A/D module is by the A/D interface of an electromagnetic isolation module access ARM chip; The D/A module is by the D/A interface of another electromagnetic isolation module access ARM chip; Air inlet electromagnetic valve is by the PWM interface of a solenoid valve driving module access ARM chip, and pressure-releasing electromagnetic valve is by the PWM interface of another solenoid valve driving module access ARM chip; Keysheet module is by keystroke interface access ARM chip; LCD MODULE is by LCD interface access ARM chip.

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