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1、大连民族学院机电信息工程学院自动化系电气控制技术课程设计报告 题 目：PLC恒温控制器设计专 业：自动化班 级：自动化091班学生姓名：组长：xx 组员：xx xx指导教师：xx设计完成日期： 2012年 6月30日目 录1 设计任务12 电炉恒温控制系统的总体设计12.1 电炉恒温控制系统的基本组成22.2 电炉恒温控制系统的硬件总体方案22.2.1 控制器22.2.2 检测装置22.2.3 执行机构32.2.4 硬件连接32.3 电炉恒温控制系统的软件总体方案33 电炉恒温控制系统的设计与实现53.1 控制器的设计53.2 程序设计与实现64 系统综合实验调试74.1 调试方案74.2 调
2、试过程74.2.1 模拟量采集的验证和调试74.2.2 温度PID控制功能块FB58功能的实现和调试74.2.3 PID参数整定与总体优化7结 论11参 考 文 献12附录A 温度PID控制功能块FB58的参数设置图13附录B 系统硬件组态与模块选择图17PLC恒温控制器设计1 设计任务设计题目要求采用所给的设备(S7-300系列PLC、固态继电器、温度传感器等)实现对电炉温度的恒温控制，完成对控制器的综合设计。该题目是基于PLC的电炉温度控制系统。电炉是热处理常用设备之一，维持电炉某一范围的温度恒定是必须要解决的问题。电炉的发热体为电阻丝。电炉通常采用模拟仪表测量温度，并通过控制交流接触器的
3、通断时间比例来控制加热功率，由于模拟仪表本身的测量精度差，加上交流接触器的寿命短，通断比例低，故控制精度低。本次设计一个采用西门子公司S7-300系列PLC可编程序控制器实现对电炉温度的自动控制。PLC的模拟量输入模块反馈的炉温实际值与设定值的偏差进行PID运算，运算结果输出控制电炉平均功率的大小，来达到控制炉温的目的。 2 电炉恒温控制系统的总体设计2.1 电炉恒温控制系统的基本组成由PLC控制的电炉温度控制系统构成如图2.1所示，系统的主要工作过程是通过修改设定值（0200）输入PLC主机，再通过PLC控制器传递给数字量输出模块，控制固态继电器的开关状态，继而控制电炉的加热情况；通过温度检
4、测装置热电阻检测到的变换为电流信号的炉温值通过模拟量输入模块读入PLC主机，由PLC主机内部PID的程序与温度设定值相比较，对数字量输出模块进行下一步的控制。整个系统PLC西门子S7-300是整个系统的核心环节，也是整个控制系统的设计重点和难点。PLC主机设定值给定PID控制算法执行器行构温度传感器控制器图2.1 电阻炉温度控制系统图实际温度电炉2.2 电炉恒温控制系统的硬件总体方案2.2.1 控制器根据系统的总体设计方案，控制器的选择即为西门子S7-300PLC模块的选择。采用PLC的电源模块、CPU模块（313C_2DP）和模拟量输入模块（SM331 AI 212bit），由于所选用CPU
5、属于紧凑型，32KB RAM，24VDC电源，内置16DI/16DO，带集成功能，MPI，PROFIBUS DP主/从接口；CPU运行需要MMC。由于系统的开关量输出仅需1个输入点，所以无需再选择附加的DO模块，也简化的硬件组态。2.2.2 检测装置温度检测环节，确定采用铂热电阻PT100，它利用铂丝的电阻值随着温度的变化而变化这一基本原理设计和制作的，按0时的电阻值R()的大小分为10欧姆（分度号为Pt10）和100欧姆（分度号为Pt100）等，测温范围均为-200850，满足设计需要。2.2.3 执行机构执行机构选择固态继电器（Solid State Relay,缩写SSR），是由微电子电
6、路，分立电子器件，电力电子功率器件组成的无触点开关。用隔离器件实现了控制端与负载端的隔离。固态继电器的输入端用微小的控制信号，达到直接驱动大电流负载。固态继电器是具有隔离功能的无触点电子开关，在开关过程中无机械接触部件。根据系统的设计需要确定选择单相固态继电器，型号为SSR-40 DA，铭牌上输入为332V直流输入，输出为24240V交流输出，而西门子S7-300PLC的数字量输出模块输出电压为24V，所以满足本设计的要求。2.2.4 硬件连接根据西门子S7-300PLC模块以及热电阻和固态继电器的型号的选择，系统的大体的硬件连接图如图2.2所示。电阻炉+数字地Q124.0模拟地V/Iin0-
7、V/Iin0+SSR热电阻SM331 AI 212bitDI16/DO16西门子S7-300PLC图2.2 电炉恒温控制系统硬件接线图2.3 电炉恒温控制系统的软件总体方案由于该电炉恒温控制系统是个闭环自动控制系统，选择采用PID控制规律。PID控制器的输入输出关系可表示为： (2.1)其中，为比例增益，为积分时间，为微分时间，e(t)为偏差，M(t)为输出。数字P1D控制系统如图2.3所示，图中SP(t)是给定值PV(t)为反馈量，C(t)为输出值：图2.3 数字PID控制系统PV(t)C(t)Mv(t)ePIDD/A继电器电炉热电阻A/DSP(t)3 电炉恒温控制系统的设计与实现3.1 控
8、制器的设计电炉恒温控制系统的控制器部分，属于软件程序的编译部分。由于西门子S7-300PLC提供了闭环控制系统的功能块和系统功能块。根据温度控制系统的特殊要求，这次课程设计采用了闭环控制功能块FB58和标度变换功能FC106。在西门子S7-300PLC的编程软件Step7中，标准库（Libraries/Standard Library/PID Control Blocks）中的PID控制块中提供了两个用于温度控制的功能块FB58和FB59。其中，FB58用于具有连续或脉冲输入信号的执行器的温度控制器，而FB59用于类似于定位电机的执行器的步进温度控制器。除了基本的功能之外，FB58还提供PID
9、的参数自整定功能。PID功能块是纯软件控制器，相关运算数据存放在相应的背景数据块中，对于不同的回路，应该使用不同的背景数据块，否则会导致PID运算混乱的错误。FB58可以用在仅加热的温度控制回路，也可以用在仅冷却的温度控制回路。和常规PID功能块（例如FB/SFB41）对比，FB58具有如下特性：提供控制带（Control Zone）功能；控制输出提供脉冲方式；过程值转换增加对温度信号转换（PV_PER*0.1/0.01）方式的支持；参数保存和重新装载；控制器参数自整定功能；设定值变化时的比例作用弱化功能。电炉恒温控制系统的程序流程图如图2.4所示。Y设定温度值采集温度值，读入PLC检测是否有
10、偏差PID运算控制图2.4 电炉恒温控制系统程序流程图控制脉冲输出，驱动固态继电器行器结束开始3.2 程序设计与实现根据软件总体的设计方案和FB58的相关资料，开始进入系统控制器的程序设计阶段。主程序采用了循环中断组织块OB35，在其中调用标度变换功能FC105和温度PID控制功能块FB58，对其中参数进行设置和调试，通过对偏差的PID运算控制脉冲输出，进而实现对温度的恒定控制。4 系统综合实验调试4.1 调试方案系统实验调试的重点是软件部分的调试，首先还是先把程序编写正确，保证没有语法错误。调试分为一下三个部分，第一部分是模拟量采集以及标度变换的验证和调试；第二部分是温度PID控制功能块FB
11、58功能的实现与调试；第三部分是PID参数的整定以及系统整体的优化和改善。4.2 调试过程4.2.1 模拟量采集的验证和调试由于模拟量的采集过程与许多因素有关，所以这个过程是个难点，它与接线、量程设置以及设备本身都有很大关系，这部分的调试也占用了比较大的时间。通过多次实验，以及同学和指导老师的帮助，最终发现了问题在于AI模块的量程卡的设置有问题。解决这一问题的方案是将模块拆卸下来改变量程卡的设置，选用为四线制信号，并保证与软件中AI模块属性设置保持一致。通过大家的一起努力，模拟量可以成功采集。4.2.2 温度PID控制功能块FB58功能的实现和调试继模拟量和标度变换成功完成以后，程序调试的重要
12、部分就是FB58模块功能的调试。该模块能否成功运行取决于对其中参数的正确设置，经过搜集资料和相关文献，知道了FB58的主要使用方法和各个参数的含义和设置方法。其中，比较主要的是相关周期的选择，CYCLE时间不能超过积分时间的的10%；为了保证控制精度，脉冲周期PER_TM应该至少是CYCLE_P的50倍；脉冲周期时间CYCLE不能超过积分时间的50%。根据以上周期的设置原则，确定了CYCLE=0.6s、CYCLE_P=0.1s、PER_TM=5s，以满足系统对周期的要求，保证系统的正常运行。4.2.3 PID参数整定与总体优化完成了系统的基本功能以后，接下里就是对功能块的参数进行细致的调整，兼
13、顾系统的准确性、快速性和稳定性。通过修改比例增益、积分时间、微分时间，同时修改控制带，调整比例弱化作用等相关参数，此外利用FB58自带的PID参数的自整定功能，共同完成对系统PID参数的整定以及整体系统功能的优化。具体的参数设置如图4.1所示。 图4.1 温度PID控制功能块FB58部分参数图最终系统可以实现快速跟踪、超调小和稳态误差小等性能指标，基本完成了温控系统的设计任务。系统主程序运行监视效果图如图4.2所示。 图4.2 主程序运行监视效果图在PID自整定过程中，初期有过超调量过大的情况，通过对输出限幅以及比例弱化作用参数的调整，实现了比较满意的响应曲线，调整前后的对比效果如图4.3所示
14、。 图4.3 PID参数整定前后效果对比图结 论电炉恒温控制系统利用了PLC技术，采用软硬件结合，较好的解决了传统加热炉温控系统中出现的问题。本实验采用了西门子S7-300PLC可编程控制器，很好的实现了电炉的恒温控制，涉及到的方法简单，设计便捷有效，精度高，工作可靠，易于拓展，最终系统可以实现快速跟踪、超调量小和稳态误差小等性能指标，基本完成了温控系统的设计任务。此外PLC内部的温度PID控制功能块FB58使用简单易于上手，为此次恒温控制系统的设计带来了许多便利，也为今后系统设计提供了一个很好的思路。参 考 文 献1 李凤阁，佟为明主编，电气控制与可编程控制器应用技术.机械工业出版社,200
15、7.8.2 吴波，张静主编，PLC在热处理电阻炉温度控制系统设计中的应用，China Academic Journal Electronic Publishing House，2006.27（6）3 机电学院自动化系电气控制与PLC课组编，电气控制与PLC应用实验指导书. 4 廖常初. S7-300/400 PLC应用技术, 北京: 机械工业出版社, 2010年.5 胡健主编. 西门子S7-300 PLC应用教程, 北京: 电子工业出版社, 2007.2附录A 温度PID控制功能块FB58的参数设置图附录B 系统硬件组态与模块选择图129（英文版 ） easily blame, to prev
16、ent the broken window effect. Supervise the leading cadres to play an exemplary role, take the lead in the strict implementation of the and , lead to safeguard the solemnity and authority of the party discipline, ensure that the party discipline and the laws and regulations for implementation in pla
17、ce. Throughout the discipline in the daily supervision and management, strengthen supervision and inspection, from the thorough investigation of violations of discipline behavior. Strengthen to key areas, key departments and key projects as well as the masses reflect the concentration of the units a
18、nd departments for supervision. - strengthening supervision, discipline inspection and supervision of cadres to set an example for compliance with the and is a man must be hexyl, blacksmith needs its own hardware. Discipline inspection organs as the executor of the party discipline, and supervisor o
19、f the defenders, for its supervision must be more strictly, discipline inspection and supervision of cadres to firmly establish the awareness of Party Constitution, sense of discipline and rules consciousness, politics loyalty, sense obey. Action speak Ji Ordinance to set an example of the regulatio
20、ns of the rule of law, strengthen supervision and accept the supervision of the firmness and consciousness, do comply with and . To firmly establish the discipline must first be disciplined, the supervisor will be subject to the supervision of concept, and consciously safeguard and implement party c
21、ompasses party, take the lead in practicing three strict real strict, so loyal, clean, play. To be good at learning, the Constitution and the as morality, politics and brought to fruition; to implement , do not want to, dare not, not with disciplinary ruler to supervision; to discipline a ruler, oft
22、en the control inspection, and consciously in the ideological red line to draw the row Ming Good accumulation is indeed the bottom line, so that the heart has fear, said to have quit, the line has ended. Attached: indifferent to heart, calmly to the table in our life, there are many unpredictable th
23、ings will happen, some good, some bad things, we cannot control is powerless to stop, but with time, you will find in life sometimes turns out to be not good, some bad things finally turned out to be a good thing, but then we muddy however did not know, this is the life teach us things. 1, life can
24、be complex, can also be simple. Want simple life of precipitation, to have enough time to reflect, to make Become more perfect. Life is the most important thing is not to win, but the struggle; not to have conquered, but to have fought well. 2, the plain is the background of life. Live a plain life,
25、 give up on themselves is not a coward, but the wise answers; not disillusioned after the heart, such as ashes, but experience the storm after the enlightenment; not unrewarding perfunctorily, but calm attitude of life of unrestrained self-confidence. Plain living, there is no noise noisy, no earthl
26、y troubles, more did not fill in the discontent of desire, some just a calm, a calm. 3, memory of heart will not good things to erase the, life is a When no movie, pain is a beginning, the struggle is a kind of process, death is a kind of ending. Give up this giving up is the helpless, do not give u
27、p the abandoned, do not give up this giving up is ignorance, do not give up should not give up is persistent. 4, a thing figured is heaven, think impassability is hell. Since the living, to live better. Sometimes we because of too narrow-minded, too care around the chores and penny wise and pound fo
28、olish, not worth the candle. Some things to attract trouble and worry, completely depends on how we look at and deal with it. Dont always take everything back to things, and dont get into a blind alley, dont want to face, dont be narrow-minded. Poke to care, is a kind of open-minded, a free and easy
29、. 5, I am not afraid of others behind me a knife, I afraid to look back and see stab me, is my intention to treat people; I am not afraid of the truth to tell the best friend, Im afraid he turned to it as a joke to tell dont 6, when we are in a positive frame of mind, you will find many good things;
30、 and when we are in a negative state of mind, you will find many depressed things; life happy and worry, all is you of life attitude, optimistic, good luck; loss of sink, Eritrea company. When you are in adversity, may wish to change a point of view to think everything over to the good Think, becaus
31、e good mentality decided the fate of the! 7, people are tired, rest; heart tired, calm. Grow up, mature, this society read. Tired and sad, squat down, to their a hug. Because the world no one can sympathize with you, have mercy on you. You cry, tears is your own; you pain, no one can understand. The
32、n you only tears to smile. 8, each people have youth,Each youth are a story, the life of the world never gets easier, I want what, wish the world all know, as has been the same; now want anything, for fear that others know, or like to lose the same. 9, the heart move, everything in the world is foll
33、owed by birth, Rangrang, important thing is often the most difficult to open ones mouth, because words will reduce its importance; to let strangers people care about your life in the good things, the original is not easy 10, do not blame, do not laugh at who, also dont envy who. Like a person is a k
34、ind of feeling, not like a person is true. The truth is easy to explain, I feel Is unspeakable. The best travel life is that you in a strange place found a long lost touched. 11, happy life not in the bustling in, and in the peace of mind; no matter how many grievances, how uncomfortable, and ultima
35、tely to heal themselves or their own, others may got you to comfort, but never know your heart is how wanjianchuanxin. 12, maam, like a movie, learn to appreciate, learn to be grateful, learn tolerance, and goodness, helping others. Instead of accusing the society, as into one; and an exception is b
36、etter to give than to what 13, dont envy him A sum of, dont lose your life and the life, respectively is: the former is a we experienced cannot escape in a day finally will last minute, while the latter is our persistent, we want to cherish the memory of those people and things. 14, learn to smile,
37、learn to strong, the world you know so many people, so many people and you are, you cannot change also cant let everyone like you, so also do not want to do. Life is too short to go crazy to love to go to waste, to chase the dream to regret. 15, when temper, a blessing to go. A wounding elegant peop
38、le, the key is to control their own emotions. With the mouth is the most stupid behavior. A control negative emotions than a can take a city more powerful water flow slow, language is expensive. People spent two years of time to learn to speak, but to spend a few years time to shut up. That is a kin
39、d of ability, that is a kind of wisdom. 16, life is not perfect, sometimes, growth is not a cry, not an eyeful of tears, there is no trace of emotion, there is no gleam of hope, no desire, no action, no static, there is only one kind of downward sinking feeling, sink A murky? 6? 7? 6? 7 sink? 6? 7?
40、6? 7 toward the bottom of the sink. 17, in some way, do not go, you will not know the other side scenery is beautiful. To you is not good, you do not mind too much, no one has an obligation to you; you learn knowledge, is you have weapons, you can start from scratch, but not unarmed; how do you trea
41、t people, does not represent how others treat you, if cannot see through this point, only inviting worry. 18, time is like a sponge in the water, as long as you are willing to squeeze, the total water is still there. Every life, after the ups and downs The best test of live, to life, survival and co
42、ntinuation, do not stop the struggle in the joys and sorrows of life on the road, so that different soul to bear life beat, acceptance of suffering. 19, indifferent to heart, calmly in table, elegant and comfortable life, do not take what is so important. The pursuit will be disappointed; to be aliv
43、e, you will have trouble. Life is the most afraid of what all want to care about, but also what all grasp is not firm, without scenery, separated populations, such as not to desire, all docked in the fate of the end. Why is too rigid, the natural, to go stay not to live, let go of obsession, revel i
44、s 20, if the fate of the broken Hopes of sailing, please dont despair, the coast is still, if the fate of the withered petals of the beautiful, please do not sink, the spring is still, life will always be endless trouble, please dont helpless, because they are still alive, is still a dream, the sun
45、still, we still. Lost, keep memories; to get, must work to; but the most important is good to cherish their own. 21, life, select the complex, is to choose the pain; choose a simple, is choose to be happy. The complex world like aSignificance of pride. Hope is the ornate palace, outside people admir
46、ing the magnificent, living in the deep knowledge of living it to pay the price. Simple world as a simple log cabin outside ridiculed shabby, the heart is willing to go live to know the joy. Suffering and joy is their own choice. 22, learn how to use a single powerful heart, let the past be the past
47、, let the future come. Life is really the end of the end of an eagle is flying wings, life is constantly pursuit. Dont miss to regret, dont wait for old just miss. Time to return, seize every moment, again painstakingly again tired also Those struggling to fly. 23, life could not Yimapingchuan, even flat pavement, inevitably there will be a few pieces of roadblocks. Some of the rocks around the past, while others have to move it out. Just move others pu