2022年毕业设计-基于PLC的液位控制系统设计.docx

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1、精选学习资料 - - - - - - - - - 电信学院毕业设计任务书题目基于 PLC 的污水池液位掌握系统设计系主任同学姓名班级学号题目类型工程设计指导老师魏祥林一、毕业设计（论文）的技术背景和设计依据：与传统的人工调剂液位掌握系统相比,变频液位自动掌握系统具有节能成效显著、人工劳动强度低,系统工作牢靠、自动化程度高等优点；为了实现污水池液位的恒定掌握,本设计要求 频器的掌握、 PID 掌握算法的实现；二、毕业设计（论文）的任务S7-200 PLC 作为掌握器,完成对现场数据的采集、变1、熟识题目要求,查阅相关科技文献,写出开题报告；2、方案设计（包括方案论证与确定、技术经济分析等内容）；

2、3、硬件系统设计；4、软件系统设计；6、撰写设计说明书,绘制图纸；6、翻译一篇与自己所学专业或设计有关的英文资料；三、毕业设计（论文）的主要内容、功能及技术指标：1、系统要求用户能够直观地明白现场设备地工作状况及水位的变化；2、要求用户能够远程掌握变频器的启动和停止；3、用户可以自行设置水位的高、低,以及掌握变频器的启、停；4、变频器及其他设备的故障信息能够准时反映在远程单片机上；5、具有水位过高、过低报警和提示用户功能；6、专业英文文献翻译；PLCs -Past, Present and Future Everyone knows theres only one constant in th

3、e technology world, and thats change. This is especially evident in the evolution of Programmable Logic Controllers PLC and their varied applications. From their introduction more than 30 years ago, PLCs have become the cornerstone of hundreds of thousands of control systems in a wide range of indus

4、tries. At heart, the PLC is an industrialized computer programmed with highly specialized languages, and it continues to benefit from technological advances in the computer and information technology worlds. The most prominent of which is miniaturization and communications. The Shrinking PLC When th

5、e PLC was first introduced, its size was a major improvement - relative to the hundreds of hard-wired relays and timers it replaced. A typical unit housing a CPU and I/O was roughly the size of a 19 television set. Through the 1980s and early 1990s, modular PLCs continued to shrink in footprint whil

6、e increasing in capabilities and performance see Diagram 1 for typical modular PLC configuration. 1 名师归纳总结 - - - - - - -第 1 页,共 43 页精选学习资料 - - - - - - - - - In recent years, smaller PLCs have been introduced in the nano and micro classes that offer features previously found only in larger PLCs. This

7、 has made specifying a larger PLC just for additional features or performance, and not increased I/O count, unnecessary, as even those in the nano class are capable of Ethernet communication, motion control, on-board PID with autotune, remote connectivity and more. PLCs are also now well-equipped to

8、 replace stand-alone process controllers in many applications, due to their ability to perform functions of motion control, data acquisition, RTU remote telemetry unit and even some integrated HMI human machine interface functions. Previously, these functions often required their own purpose-built c

9、ontrollers and software, plus a separate PLC for the discrete control and interlocking. The Great Communicator Possibly the most significant change in recent years lies in the communications arena. In the 1970s Modicon introduction of Modbus communications protocol allowed PLCs to communicate over s

10、tandard cabling. This translates to an ability to place PLCs in closer proximity to real world devices and communicate back to other system controls in a main panel. In the past 30 years we have seen literally hundreds of proprietary and standard protocols developed, each with their own unique advan

11、tages.Todays PLCs have to be data compilers and information gateways. They have to interface with bar code scanners and printers, as well as temperature and analog sensors. They need multiple protocol support to be able to connect with other devices in the process. And furthermore, they need all the

12、se capabilities while remaining cost-effective and simple to program. Another primary development that has literally revolutionized the way PLCs are programmed, communicate with each other and interface applications, came from the computing world. with PCs for HMI, SCADA or DCS Use of Ethernet commu

13、nications on the plant floor has doubled in the past five years. While serial communications remain popular and reliable, Ethernet is fast becoming the communications media of choice with advantages that simply cant be ignored, such as: * Network speed. * Ease of use when it comes to the setup and w

14、iring. * Availability of off-the-shelf networking components. * Built-in communications setups. Integrated Motion Control Another responsibility the PLC has been tasked with is motion control. From simple open-loop to multi-axis applications, the trend has been to integrate this feature into PLC har

15、dware and software. 2 名师归纳总结 - - - - - - -第 2 页,共 43 页精选学习资料 - - - - - - - - - There are many applications that require accurate control at a fast pace, but not exact precision at blazing speeds. These are applications where the stand-alone PLC works well. Many nano and micro PLCs are available with

16、 high-speed counting capabilities and high-frequency pulse outputs built into the controller, making them a viable solution for open-loop control. The one caveat is that the controller does not know the position of the output device during the control sequence. On the other hand, its main advantage

17、is cost. Even simple motion control had previously required an expensive option module, and at times was restricted to more sophisticated control platforms in order to meet system requirements. More sophisticated motion applications require higher-precision positioning hardware and software, and man

18、y PLCs offer high-speed option modules that interface with servo drives. Most drives today can accept traditional commands from host PLC or PC controls, or provide their own internal motion control. The trend here is to integrate the motion control configuration into the logic controller programming

19、 software package. Programming Languages A facet of the PLC that reflects both the past and the future is programming language. The IEC 61131-3 standard deals with programming languages and defines two graphical and two textual PLC programming language standards: * Ladder logic graphical. * Function

20、 block diagram graphical. * Structured text textual.Instruction list textual. This standard also defines graphical and textual sequential function chart elements to organize programs for sequential and parallel control processing. Based on the standard, many manufacturers offer at least two of these

21、 languages as options for programming their PLCs. Ironically, approximately 96 percent of PLC users recently still use ladder diagrams to construct their PLC code. It seems that ladder logic continues to be a top choice given its performed so well for so long. Hardware Platforms The modern PLC has i

22、ncorporated many types of Commercial off the Shelf COTS technology in its CPU. This latest technology gives the PLC a faster, more powerful processor with more memory at less cost. These advances have also allowed the PLC to expand its portfolio and take on new tasks like communications, data manipu

23、lation and high-speed motion without giving up the rugged and reliable performance expected from industrial control equipment. New technology has also created a category of controllers called Programmable Automation Controllers, or PACs. PACs differ from traditional PLCs in that they typically utili

24、ze open, modular architectures for both hardware and software, using 3 名师归纳总结 - - - - - - -第 3 页,共 43 页精选学习资料 - - - - - - - - - de facto standards for network interfaces, languages and protocols. They could be viewed as a PC in an industrial PLC-like package. The Future A 2005 PLC Product Focus Stud

25、y from Reed Research Group pointed out factors increasingly important to users, machine builders and those making the purchasing decisions. The top picks for features of importance were. * The ability to network, and do so easily. Ethernet communications is leading the charge in this realm. Not only

26、 are new protocols surfacing, but many of the industry de facto standard serial protocols that have been used for many years are being ported to Ethernet platforms. These include Modbus ModbusTCP, DeviceNet Ethernet/IP and Profibus Profinet. Ethernet communication modules for PLCs are readily availa

27、ble with high-speed performance and flexible protocols. Also, many PLC CPUs are now available with Ethernet ports on board, saving I/O slot space. PLCs will continue to develop more sophisticated connectivity to report information to other PLCs, system control systems, data acquisition SCADA systems

28、 and enterprise resource planning ERP systems. Additionally, to gain popularity. wireless communications will continue * The ability to network PLC I/O connections with a PC. The same trends that have benefited PLC networking have migrated to the I/O level. Many PLC manufacturers are supporting the

29、most accepted fieldbus networks, allowing PLC I/O to be distributed over large physical distances, or located where it was previously considered nearly impossible. This has opened the door for personal computers to interface with standard PLC I/O subsystems by using interface cards, typically suppli

30、ed by the PLC manufacturer or a third party developer. Now these challenging locations can be monitored with today a PC. Where industrial-grade control engines are not required, the user can take advantage of more advanced software packages and hardware flexibility at a lower cost. * The ability to

31、use universal programming software for multiple targets/platforms. In the past it was expected that an intelligent controller would be complex to program. That is no longer the case. Users are no longer just trained programmers, such as design engineers or systems integrators, but end-users who expe

32、ct easier-to-use software in more familiar formats. The Windows-based look and feel that users are familiar with on their personal computers have become the most accepted graphical user interface. What began as simple relay logic emulation for programming PLCs has evolved into languages that use hig

33、her level function blocks that are much more intuitive to configure. PLC manufacturers are also beginning to integrate the programming of diverse functions that allow you to learn only one package in configuring logic, HMI, motion control and other specialized capabilities. Possibly the ultimate wis

34、h of the end-user would be for a software package that could seamlessly program many manufacturers PLCs and sub-systems. After all, Microsoft Windows operating system and applications work similarly whether installed on a Dell, HP or IBM computer, which makes it easier for the user. 4 名师归纳总结 - - - -

35、 - - -第 4 页,共 43 页精选学习资料 - - - - - - - - - Overall, PLC users are satisfied with the products currently available, while keeping their eye on new trends and implementing them where the benefits are obvious. helping them Typically, new installations take advantage of advancing technologies, become mo

36、re accepted in the industrial world. PLC的过去、现在与将来 众所周知,科技世界里只有一个永恒真理,那就是变化；这在可编程规律掌握器（PLC）及其各种应用的进展过程中尤为明显；自从三十多年前将 PLC引进以来, PLC已经在广泛的 工业领域中成为几十万掌握系统的基础；从本质上讲, PLC 是一种用高度专业化语言编程的工业运算机,并连续受益于运算机和 信息技术领域的技术进步；它的最突出之处是小型化和通信功能；微型化的 PLC 在最初引进 PLC的时候,主要改进它的体积, 这与替换了数百个硬接线继电器和计时器有 关；一个嵌有 CPU和 I/O 的典型单元有大约

37、 19 寸电视机那么大；从 20 世纪 80 岁月到 20 世 纪 90 岁月初,模块化的 PLC逐步微型化,同时它的容量和性能也得到了提高；PLC已经进展到纳米级和微型级,它们已具有以前只在大型 PLC上才有 近年来,更小型 的特点；因此仅为了额外特性或性能而不是增加 I/O 容量而详细指定一个大型的 PLC变得不 必要,由于即使纳米级 PLC也具备以太网通信、运动掌握、自动调谐的嵌入式 PID、远程连 通性等更多的功能；现在,由于 PLC能执行运动掌握、数据采集,远程终端单元（RTU）甚至一些集成人机介 面（HMI）等功能,因此 PLC在很多应用中也已配置齐全从而替代单一的过程掌握器；以前

38、,这些功能通常要求他们自身内置实现这些功能的掌握器和软件,此外,仍需要一个用于离散 掌握和互锁的独立的 PLC；强大的通信功能 近年来,最有意义的变化或许发生在通信领域； 在 20 世纪 90 岁月,Modicon 推行的 Modbus 通信协议,答应 PLC通过标准电缆进行通信；这为 PLC更好地适用于现存的设备供应了可能 性,并且向主板上的其它掌握系统通信成为可能；在过去的 30 年里,我们真实地目睹了数百个专利化协议和标准化协议的进展,每一个协议都有自己特殊的优势；现在,PLC 已成为数据编译器和信息网关,它们必需接入条形码扫描器和打印机,仍有温度和模拟传感器；在过程掌握中,它们需要支持

39、多种协议,以便它们 能和其它设备通信；此外,在它们全部具备这些功能的同时,它们仍旧要有高的性价比而且编程简洁；另一个主要改进来自于运算处理领域；准确地说,它革命化了 PLC的编程方式、相互通 信、与用于 HMI、SCADA和 DCS的 PC有接口；在过去的五年中,车间级以太网通信的应用已经翻了一倍；尽管串行通信仍旧很受欢迎 并且很牢靠,但以太网快速地成为值得挑选的通信媒体,它有着不能被忽视的优势,例如：网速、设置简洁、布线便利、现成网络组件的可用性、嵌入式通信设置 集成运动掌握另一个安排给PLC的任务是运动掌握；从简洁的开环掌握到多轴应用来看,在PLC的软件和硬件中集成运动掌握已经成为一个趋势

40、；很多系统在快速运行时要求精确的掌握,但并不是在超高速运行时的肯定精准；单机 PLC在一些系统上也能很好地运行；很多纳米级和微型级PLC都有高速运算才能和掌握器内置的高频脉冲输出才能,使它们成为开环掌握的可行解决方案；一方面要提示的是掌握器在掌握次序上不能确定输出设备的位置；另一方面要提示的是 它的主要优势在于它的成本；以前,即使简洁的运动掌握也要求有一个昂贵的挑选模块；有5 名师归纳总结 - - - - - - -第 5 页,共 43 页精选学习资料 - - - - - - - - - 时为了满意系统需求,它不能用于更精密的掌握平台中；越精密的运动掌握系统要求越高精度的定位硬件和软件,而很多

41、 PLC都供应高速挑选模 块接入伺服驱动；现在,很多驱动都兼容来自掌握主机（PLC或 PC）的传统命令,或者供应自身的内部运动掌握；将运动掌握组态软件集成在PLC编程软件包中将成为一种趋势；编程语言PLC历史的一个方面；国际电工委员会61131-3 标准（ IEC 61131-3）处编程语言是反映理了编程语言并且定义了两个图形化的和两个文本化的PLC编程语言标准：梯形规律（图形化） 功能块图（图形化）结构化文本（文本化）指令表（文本化）这项标准也定义了为顺序掌握和并行掌握处理组织程序的图形化的和文本化的顺控功能图元素；基于这项标准,许多 PLC生产商供应最少三种语言中的两种作为他们PLC编程时

42、的语言挑选；讽刺的是,在近来接触的 PLC使用者中,有大约96%仍旧使用梯形图编写PLC代码；由于梯形图长期的良好表现,因此梯形图编程好像会连续成为最好的挑选；硬件平台现代的 PLC已经在它们的 CPU里集成了多种的商业非定制（COTS）技术；最新的技术为PLC供应了一个更快,更强,储备量更大且成本更低的处理器；这些先进技术也为 PLC扩展集成和接受新任务（如通信、数据处理和高速运动）留出空间,而不会以牺牲工业掌握设备所要求的严格牢靠性为代价；新技术已经制造了另一种掌握器可编程自动化掌握器（PAC）；PAC与传统的 PLC 有所不同,这是由于 PAC在软件和硬件上都采纳了开放的模块化体系结构,

43、并且采纳了网络接口、语言和协议的已知标准； 它们可以被看作为一个置于工业的类 PLC程序包里的 PC；展望将来来自 Reed讨论团的一份 2005 年 PLC产品聚焦讨论指出了一些对于 PLC使用者、机器制造商和选购决策人员愈加重要的因素；排在最前的、有重要特点的因素是：1联网才能和易用性以太网通信在通信领域中独占熬头；不只是新协议在逐步平面化,很多已经使用了很多年的工业标准化协议也在逐步地接入到以太网平台上,这些协议包括 Modbus ModbusTCP、DeviceNet Ethernet/IP 和 Profibus Profinet；PLC的以太网通信模块已经具有高速性能和敏捷性的协议群

44、；同样,很多PLC上的 CPU在工作时已经可以接入以太网,这就节约了I/O 槽空间； PLC将会连续开发更成熟的连通性,使它可以将信息传输到其它 PLC系统、系统掌握系统、数据采集（ SCADA）系统和企业资源方案（会进一步普及；2用 PC连接 PLC输入 / 输出（ I/O ）的才能ERP）系统上；另外,无线通信方式将同样的一个趋势, 过去与 PLC联网获益良多, 但现在已经转移到了 I/O 水平上；很多 PLC生产商已经支持最受大众接受的现场总线网络,使 PLC的 I/O 可以安排在宽阔的区域上或者定位在以前被认为是几乎不行能的位置上；这使个人电脑通过使用接口卡接入到标准 PLC的I/O

45、子系统成为可能,而这种接口卡主要是由 些具挑战性的宽阔区域都可以由个人电脑监控；PLC生产商或第三方开发商供应的；现在,这 至于在不需要技术等级掌握引擎支持的地方,使用者可以利用更为先进的软件包和硬件机动性,这成本也比较低廉；3使用通用编程软件编制多对象 / 平台的才能过去,人们都认为一个智能型掌握器需要复杂的编程,但现在不再是这样了；使用者不再只是受过培训的编程人员 （如设计工程师和系统集成人员） ,而是在更熟识的设计上期望能用上人性化软件的最终用户； 在他们个人电脑上, 基于视窗 Windows的外观和触感是最为人所熟识的,它已成为最受大众接纳的图形用户界面；开头时,用于为 PLC编程的简

46、洁继电逻辑仿真已经进展成为使用更高级功能块的编程语言（这些功能块可以更直观在配置出来） ；PLC生产商也已经开头一体化不同功能块的编程,使你在构造规律、HMI、动态掌握和其它特定功6 名师归纳总结 - - - - - - -第 6 页,共 43 页精选学习资料 - - - - - - - - - 能时只需学习一个编程软件包； 或许,最终用户的最终愿望是获得一个可以无缝地为多个 PLC和子系统编程的软件包；究竟,无论是安装在 Dell 、HP电脑上仍是安装在 IBM电脑上,微软 的视窗（ Windows）操作系统和应用程序都是同样地运行,这就便利了系统用户；总的来说, PLC用户对现行可用的 并在他们认为有利可图的地方用上新的 更简洁地被采PLC产品感到中意；同时,他们亲密关注新的趋势,PLC产品；新 PLC利用先进的技术,使它们在工业界7 名师归纳总结 - - - - - - -第 7 页,共 43 页精选学习资料 - - - - - - - - - 无锡职业技术学院 毕业设计说明书（调研报告）关于基于