电气毕业论文英语文献原文+翻译

1、f *中外文翻译院（系）专业班级姓名学号指导教师名也学豺孩上单实习报告用纸第 页Programmable designed for electro-pneumatic systems controllerJohn F.WakerlyThis project deals with the study of electro-pneumatic systems and the programmable controller that provides an effective and easy way to control the sequence of the pneumatic actuator

2、s movement and the states of pneumatic system. The project of a specific controller for pneumatic applications join the study of automation design and the control processing of pneumatic systems with the electronic design based on microcontrollers to implement the resources of the controller.Introdu

3、ctionThe automation systems that use electro-pneumatic technology are formed mainly by three kinds of elements: actuators or motors, sensors or buttons and control elements like valves. Nowadays, most of the control elements used to execute the logic of the system were substituted by the Programmabl

4、e Logic Controller (PLC). Sensors and switches are plugged as inputs and the direct control valves for the actuators are plugged as outputs. An internal program executes all the logic necessary to the sequence of the movements, simulates other components like counter, timer and control the status of

5、 the system.With the use of the PLC, the project wins agility, becauseit is possible to create and simulate the system as many times as needed. Therefore, time can be saved, risk of mistakes reduced and complexity can be increased using the same elements.A conventional PLC, that is possible to find

6、on the market from many companies, offers many resources to control not only pneumatic systems, but all kinds of system that uses electrical components. The PLC can be very versatile and robust to be applied in many kinds of application in the industry or even security system and automation of build

7、ings.Because of those characteristics, in some applications the PLC offers to much resources that are not even used to control the system, electro-pneumatic system is one of this kind of application. The use of PLC, especially for small size systems, can be very expensive for the automation project.

8、An alternative in this case is to create a specific controller that can offer the exactly size and resources that the project needs 3, 4. This can be made using microcontrollers as the base of this controller.The controller, based on microcontroller, can be very specific and adapted to only one kind

9、 of machine or it can work as a generic controller that can be programmed as a usual PLC and work with logic that can be changed. All these characteristics depend on what is needed and how much experience the designer has with developing an electronic circuit and firmware for microcontroller. But th

10、e main advantage of design the controller with the microcontroller is that the designer has the total knowledge of his controller, which makes it possible to control the size of the controller, change the complexity and the application of it. It means that the project gets more independence from oth

11、er companies, but at the same time the responsibility of the control of the system stays at the designer handsElectro-pneumatic systemOn automation system one can find three basic components mentioned before, plus a logic circuit that controls the system. An adequate technique is needed to project t

12、he logic circuit and integrate all the necessarycomponents to execute the sequence of movements properly.For a simple direct sequence of movement an intuitive method can be used 1,5, but for indirect or more complex sequences the intuition can generate a very complicated circuit and signal mistakes.

13、 It is necessary to useanother method that can save time of the project, make a clean circuit, can eliminate occasional signal overlapping and redundant circuits. The presented method is called step-by-step or algorithmic 1, 5, it is valid for pneumatic and electro-pneumatic systems and it was used

14、as a base in this work.The method consists of designing the systems based on standard circuits made名4学豺政上第实习报告用纸第 页for each change on the state of the actuators, these changes are called steps.Fig. . StmdMd dmuil Ibr 曲。pneumMk kULM、rvkitions 嗝 iih oth Y.3I7dirtilyF*- 2. Slanthid ge皿 Jbr (Ik 08to即eum

15、-kt24VThe first part is to design those kinds of standard circuits for each step, the next task is to link the standard circuits and the last part is to connect the control elements that receive signals from sensors, switches and the previous movements, and give the air or electricity to the supply

16、lines of each step. In Figs. 1 and 2 the standard circuits are drawn for pneumatic and electro-pneumatic system 8. It is possible to see the relations with the previous and the next steps.The method applied inside the controllerThe result of the method presented before is a sequenceof movements of t

17、he actuator that is well defined by steps. It means that each change on the position of the actuators is a new state of the system and the transition between states is called step.The standard circuit described before helps the designer to define the states of the systems and to define the condition

18、 to each change between the states. In the end of the design, the system is defined by a sequencethat never chancesand statesthat have the inputs and the outputs well defined. The inputs are the condition for the transition and the outputs are the result of the transition.All the configuration of th

19、ose steps stays inside of the microcontroller and is executed the same way it was designed. The sequences of strings are programmed inside the controller with 5 bytes; each string has the configuration of one step of the process. There are two bytes for the inputs, one byte for the outputs and two m

20、ore for the other configurations and auxiliary functions of the step. After programming, this sequence of strings is saved inside of a non-volatile memory of the microcontroller, so they can be read and executed.The controller task is not to work in the same way as a conventional PLC, but the purpos

21、e of it is to be an example of a versatile controller that is design for an specific area. A conventional PLC process the control of the system using a cycle where it makes an image of the inputs, execute all the conditions defined by the configuration programmed inside, and then update the state of

22、 the outputs. This controller works in a different way, where it read the configuration of the step, wait the condition of inputs to be satisfied, then update the state or the outputs and after that jump to the next step and start the process again.It can generate some limitations, as the fact that

23、this controller cannot execute,&3卷4善豺政上第实习报告用纸第 页善豺投上第实习报告用纸第 页inside the program, movements that must be repeated for some time, but this problem can be solved with some external logic components. Another limitation is that the controller cannot be applied on systems that have no sequence. These li

24、mitations are a characteristic of the system that must be analyzed for each application.Characteristics of the controllerThe controller is based on the MICROCHIP microcontroller PIC16F877 6,7 with 40 pins, and it has all the resources needed for this project .It has enough pins for all the component

25、s, serial communication implemented in circuit, EEPROM memory to save all the configuration of the system and the sequence of steps. For the execution of the main program, it offers complete resources as timers and interruptions.The list of resources of the controller was created to explore all the

26、capacity of the microcontroller to make it as complete as possible. During the step, the program chooses how to use the resources reading the configuration string of the step. This string has two bytes for digital inputs, one used as a mask and the other one used as a value expected. One byte is use

27、d to configure the outputs value. One bytes more is used for the internal timer , the analog input or time-out. The EEPROM memory inside is 256 bytes length that is enough to save the string of the steps, with this characteristic it is possible to save between 48 steps (Table 1).ibk-of Inc Li.rtnJ k

28、rI -iril .ilAlukU VIJHJb bikrul 1 etic Pwll J ”印触 Luiun 44 xk pttThe controller (Fig.3) has also a display and some buttons that are used with an interactive menu to program the sequence of steps and other configurations.t m- J. CoK|Mnmhi 城 怪也41ntmlh工Interaction componentsFor the real application th

29、e controller must have some elements to interact with the final user and to offer a complete monitoring of the system resourcesthat are available to the designer while creating the logic control of the pneumatic system (Fig.3):?Interactive mode of work; function available on the main program for did

30、actic purposes, the user gives the signal to execute the step.?LCD display, which shows the status of the system, values of inputs, outputs, timer and statistics of the sequence execution.?Beep to give important alerts, stop, start and emergency.? Leds to show power on and others to show the state o

31、f inputs and outputs.SecurityTo make the final application works property, a correct configuration to execute the steps in the right way is needed, but more then that it must offer solutions in case of bad functioning or problems in the execution of the sequence.The controller 与4善豺政上第实习报告用纸第 页名也学豺孩上

32、单实习报告用纸第 页offers the possibility to configure two internal virtual circuits that work in parallel to the principal. These two circuits can be used as emergency or reset buttons and can return the system to a certain state at any time 2. There are two inputs that work with interruption to get an imme

33、diate access to these functions. It is possible to configure the position, the buttons and the value of time-out of the system.User interfaceThe sequence of strings can be programmed using the interface elements of the controller. A Computer interface can also be used to generate the user program ea

34、sily. With a good documentation the final user can use the interface to configure the strings of bytes that define the steps of the sequence. But it is possible to create a program with visual resources that works as a translator to the user, it changes his work to the values that the controller und

35、erstands.To implement the communication between the computer interface and the controller a simple protocol with check sum and number of bytes is the minimum requirements to guarantee the integrity of the data.FirmwareThe main loop works by reading the strings of the steps from the EEPROM memory tha

36、t has all the information about the steps.In each step, the status of the system is saved on the memory and it is shown on the display too. Depending of the user configuration, it can use the interruption to work with the emergency circuit or time-out to keep the system safety. In Fig.4,a block diag

37、ram of micro controller main program is presented.mam 管工 ecmho梆ixiLnry fcdsikbF. 4 RImL dimrn of it k rmgMExample of electro-pneumatic systemThe system is not a representation of a specific machine, but it is made with some common movements and components found in a real one. The system is composed

38、of four actuators. The actuators A, B and C are double acting and D-single acting. Actuator A advances and stays in specified position till the end of the cycle, it could work fixing an object to the next action for example (Fig. 5) , it is the first step. When A reaches the end position, actuator C

39、 starts his work together with B, making as many cycles as possible during the advancing of B. It depends on how fast actuator B is advancing; the speed is regulated by a flowing control valve. It was the 日3名4学豺孩上单实习报告用纸第 页33名4学豺政上事实习报告用纸第 页second step. B and C are examples of actuators working toge

40、ther, while B pushes an object slowly, C repeats its work for some time.Fi. 5 lifiK dinm A B 41u；*orThese two representationsof the system (Figs. 5 and 6) together are enough to describe correctly all the sequence. With them is possible to design the whole control circuit with the necessary logic co

41、mponents. But till this time, it is not a complete system, because it is missing some auxiliary elements that are not included in this draws because they work in parallel with the main sequence.These auxiliary elements give more function to the circuit and are very important to the final application

42、; the most important of them is the parallel circuit linked with all the others steps. That circuit should be able to stop the sequence at any time and change the state of the actuators to a specific position. This kind of circuit can be used as a reset or emergency buttons.The next Figs. 7 and 8 sh

43、ow the result of using the method without the controller. These pictures are the electric diagram of the control circuit of the example, including sensors, buttons and the coils of the electrical valves.&步与4学豺政上单实习报告用纸第 页 Tiao Mjri bu一_ 一 Auto Shimai rircuil * * HlrE LjfiruriFig. 7. EIaMjie digramuf

44、 (he tsanpk学豺孩上单实习报告用纸第 页与4学豺投上第实习报告用纸第 页* * IV o Man buiMM一一一 Auto WtlHMl l ift Uli * . * Hzt.irvun”了 N I Uik JiatfUTin d f) v4iqThe auxiliary elements are included, like the automatic/manual switcher that permit a continuous work and the two start buttons that make the operator of a machine use th

45、eir two hands to start the process, reducing the risk of accidents.6. Changing the example to a user programIn the previous chapter, the electro-pneumatic circuits were presented, used to begin the study of the requires to control a system that work with steps and must offer all the functional eleme

46、nts to be used in a real application. But, as explained above, using a PLC or this specific controller, the control becomes easier and the complexity can be increase also.Table 2 shows a resume of the elements that are necessary to control the presented example.With the time diagram, the step sequen

47、ce and the elements of the system described in Table 2 and Figs. 5 and 6 it is possible to create the configuration of the steps that can be sent to the controller (Tables 3 and 4).While using a conventional PLC, the user should pay attention to the logic of the circuit when drawing the electric dia

48、gram on the interface (Figs. 7 and 8), using the programmable controller, described in this work, the user must know only the concept o f the method and program only the configuration of each step.RcquvcnKub ul llv pvicumalic Um TOC o 1-5 h z iTivilal mpvb?I nilpuhAnolcg inpUlK(1LmtvM1omulsIJid and

49、E仃gciK9 |1bk; 3LinI ol ifiBlal inpib M Ihc765432141IrpvU17to15UB12(IkJ-sAlA2B2BlD2PII1!labb Jl.lsl divial OUtjMli 川 flic765432)1OulfMifci 07 IM 0502 O1 X)Sms Y1 Y2 Y3YS Y7It means that, with a conventional PLC, the user must draw the relation between the lines and the draw makes it hard to different

50、iate the steps of the sequence. Normally, one needs to execute a simulation on the interface to find mistakes on the logic与4学豺孩上单实习报告用纸第 页&步名4学豺技上单实习报告用纸第 页H q ii I 加-E li，l I . i7439 I0卬uu(JU00d(Jhl”1l111111fhj Fl(kCl101Ia10q1114(j口印电4。0Cl口0(loS51中上Uciu(1(11dll611111)I1IhJ卜F(1Cl0tlu巾(1的1(I)0110a(Ml

51、911llV0(IaHP1CIuu(J(1tl(1atuoo1I11111I111 J K12G1u00004期胤1.11uu1a1u03町14U0u00Cl(1u15U口uuaU10(MNI161JI11I1LhJ kJ7Ga1y0(10IK(Nu1a10【，一0QCl0(II(I(10(11417叩5(1(k(j000(1a(ItiWI21111111iU1J11uDuJ.4uCl1(1)duuuau001u25The new programming allows that the configuration of the steps be separated, like describe

52、d by the method. The sequence is defined by itself and the steps are described only by the inputs and outputs for each step.The structure of the configuration follows the order:1-byte: features of the step;2-byte: mask for the inputs;3-byte: value expected on the inputs;4-byte: value for the outputs

53、;5-byte: value for the extra function.I IL; 1(*1 mJ IX Old 5vIlSiTSTable 5 shows how the user program is saved inside the controller, this is the program that describes the control of the example shown before.The sequence can be defined by 25 bytes. These bytes can be divided in five strings with 5

54、bytes each that define each step of the sequence (Figs. 9 and 10).7. Conclusion名也学豺孩上单实习报告用纸第 页The controller developed for this work (Fig. 11) shows that it is possible to create a very useful programmable controller based on microcontroller. External memories or external timers were not used in ca

55、se to explore the resources that the microcontroller offers inside. Outside the microcontroller, there are only components to implement the outputs, inputs, analog input, display for the interface and the serial communication.Using only the internal memory, it is possible to control a pneumatic syst

56、em that has a sequencewith 48 steps if all the resources for all steps are used, but it is possible to reach sixty steps in the case of a simpler system.The programming of the controller does not use PLC languages, but a configuration that is simple and intuitive. With electro-pneumatic system, the

57、programming follows the same technique that was used before to design the system, but here the designer work s directly with the states or steps of the system.With a very simple machine language the designer can define all the configuration of the step using four or five bytes. It depends only on hi

58、s experience to use all the resources of the controller.The controller task is not to work in the same way as a commercial PLC but the purpose of it is to be an example of a versatile controller that is designed for a specific area. Because of that, it is not possible to say which one works better;

59、the system made with microcontroller is an alternative that works in a simple way.名也善豺政上第实习报告用纸第 页步与4学豺孩上单实习报告用纸第 页应用于电气系统的可编程序控制器约翰F.维克里此项目主要是研究电气系统以及简单有效的控制气流发动机的程序和气流系 统的状态。它的实践基础包括基于气流的专有控制器、自动化设计、气流系统 的控制程序和基于微控制器的电子设计。1简介使用电气技术的自动化系统主要由三个组成部分：发动机或马达，感应器或 按钮，状如花瓣的控制零部件。现在，大部分的系统逻辑操作的控制器都被程 序逻辑控

60、制器（PLC）所取代。PLC的感应器和开关是输入端，而发动机的直 接控制阀是输出端，其中有一个内部程序操控所有运行必需的逻辑，模拟其他 的装置如计算器、定时器等，对整个系统的运行状态进行控制。因为可以根据需要无数次创建和模拟这样的系统，所以藉由PLC的使用，此项目有灵活的优点。因此，可以节省时间，减少失误的危险，同时在使用相同 材料的情况下，它可以更加精密。市场上的许多家公司都使用了常规的 PLC,它不仅可以用气流系统来控制， 还可以用各种电气设备。PLC的用途广泛，可以应用于许多工业生产中，甚至 用于建筑物的安全和自动化系统中。由于以上的各种特性，在一些实际应用中 PLC提供了很多的资源，甚