外文翻譯--基于controllogix5550 plc的鍋爐水位控制系統(tǒng)（英文）

1、 Received: 2010-5-25 Corresponding author: Tao Sui(sui_t@163.com) Vol.1 Supplement Journal of Measurement Science and Instrumentation 2010 Boiler level control system based on Contr

2、olLogix5550 PLC Tao SUI, Bing LI, Zhen-xing MENG, Gui-wen REN (College of Information and Electrical Engineering, Shandong University of Science and Technology, Qingdao, 266510, China) Abstract—This paper is a resear

3、ch design based on EFPT process control device. In the design, actual industry field has been simulated and corresponding modelling has been carried on for the boiler level system. Then the appropriate PID parameter has

4、been sorted out and ControlLogix5550 PLC has been used to control the entire boiler level system. At last, a corresponding control interface has been established and the boiler level has been under a safe and accurate co

5、ntrol. Keywords — — — — EFPT; Boiler level; Modelling; PID Manuscript Number: 1674-8042(2010)supp.-0078-04 dio: 10.3969/j.issn1674-8042.2010.supp..21 1 Introduction The task of the industrial boiler level control

6、 is to maintain a dynamic balance by controlling the water flow and evaporation, so that the drum level can be maintained in the technological level, which is a necessity for ensuring safe operation and also one of

7、the main indicators of the boiler’s normal operation. Water level which is too high will affect the effect of the steam-water separation, but too low it is will break ring cycle or even cause boiler explosion. To ensu

8、re a safe and efficient production, the boiler level must be strictly controlled in maintaining constant or changing only according to a certain rule. Using Logix5550 PLC with analogy I/O modules, launched by Rockw

9、ell Automation Company as controllers, and EFPT process control experimental device as control object, this system have brought the boiler water level under an accurate control in a mini boiler system with sensors an

10、d actuators that used in industrial production. 2 System Overview This system is composed of an EFPT process control device, an inverter, a Logix5550 PLC and a computer. EFPT process control device is a simulated h

11、eating and water supply and drainage system for a micro-small boiler. It realizes process control in a mini boiler system with sensors and actuators used in industrial production. The actuator includes not only measur

12、ing appliance, but also AC inverter, heating controller, heater and so on. The system simulates industry scene through a mini-boiler heating, water supply and drainage system, which is reliable and visual. In the de

13、sign, boiler Level was selected as the controlled variable. The controlled object is composed of the water trough, the force pump, the boiler and the pipe-line valve. Micro Master 6SE9214-0DA40 inverter is taken as t

14、he actuator and the boiler level is controlled by Logix5550. Configuration software RSView32 and touch screen PanelView1000 are combined to realize the real-time monitoring. In the design, a simple design of single-l

15、oop boiler liquid level value adjustment is selected for the study. The composition of the system is shown in Fig. 1. F Fig. 1 Boiler level setting value adjustment system In the design, the inverter as an actuator dir

16、ectly receives PLC analogy I/O port output, and converters into frequency of inverter so as to drive the 3-phase motor in the lift pump, change the inlet, and adjust the boiler level to the dynamic balance at last.

17、And the configuration software is used to design monitoring picture to realize the computer and the touch screen to the boiler level long-distance and the scene monitoring. 80 Journal of

18、Measurement Science and Instrumentation Supplement 2010 algorithm is used to realize boiler level control. The schematic diagram of level control is shown in Fig. 3. PID control Given Flow rateDeviationLev

19、elLiquid Level DetectionInverterPumpvalueFig. 3 The schematic diagram of level control Open the outlet valve to a certain degree, and make the hydraulic discharge invariable. Comparing the process variables of the wat

20、er level in feedback with the given volume, the deviation can be obtained. PID instruction does PID operation on the deviation, and the results is a control variable, so the frequency of the inverter can be changed t

21、o control the rotate speed of the pump. If the liquid level is on the high side, the results make the control variable smaller, and reduce the rate of inflow, make liquid level lower; if the level is on the low side,

22、 the results make the control variable larger, and increase the rate of inflow, make liquid level higher. 4.2 The Parameter Tuning of PID Because the transfer function of the controlled object includes a zero second-o

23、rder link, the computation work load is quite big regardless of using the root-locus method or the frequency characteristic law among theory methods when tuning PID parameter. And the process mathematical model can

24、only reflect dynamic parameter approximately, so the reliability of the parameter value which is obtained by the theoretical calculation is not very accurate and it will be adjusted constantly in the scene. Therefore,

25、 engineering parameter tuning is chosen to seek the PID parameter in the design. The common method of engineering tuning are dynamic characteristic parameters, the stable boundary law, the decay curve law and f

26、ield experience settingmethod, etc. In the process of PID parameters, the 4:1 decay curve law is adopted. The steps are: 1) In the closed system, regulator’s integral time is set the largest (Ti=∞) and differential t

27、ime Td is set zero (Td = 0). The proportion is taken the great value to perform the given value perturbation experiment repeatedly, and the proportion is reduced gradually until the record curve presents up to 4:1 we

28、aken. Then the proportion is called 4:1 weaken proportion δs and the distances between two neighboring wave ridge's are called 4:1 damped cycle Ts. In the experiment, the level quantitative test is set for the 20

29、0mm, and then the system response curve is obtained and reorganized 4:1 decay curve (thick red line) is shown in Fig. 4. Fig. 4 4:1 decay curve Thus measuring:δs≈8，Ts≈2.2; 2) According to the following formula, each p

30、arameter of the regulators is δ=0.8, δs≈6.4； Ti=0.3, Ts≈6.6； Td=0.1, Ts≈2.2； 3) According to these results, regulator parameters are set. Then the dynamic process of system is observed and the parameters are made adjustm

31、ent to determine the optimum parameters. 5 Monitoring Design RSView32 software and PanelBuilder32 software of Rockwell Automation Company are respectively used to design monitor screen to complete such function

32、as animating display, parameter setting, report output, the current curve display and history curve display and so on， and make the computer and touch screen achieve the remote and on-site control to the boiler liqui