英文原文.pdf

曲面印刷机版辊及自动对版机构设计【含6张cad图纸+文档全套资料】

收藏

资源目录
跳过导航链接。
曲面印刷机版辊及自动对版机构设计含6张cad图纸文档全套资料.zip
曲面印刷机版辊及自动对版机构设计【含6张CAD图纸】
调节板.gif---(点击预览)
调节板.dwg---(点击预览)
说明书_doc_2.png---(点击预览)
说明书_doc_1.png---(点击预览)
说明书_doc_0.png---(点击预览)
说明书.doc---(点击预览)
装配图.dwg---(点击预览)
目录_doc_2.png---(点击预览)
目录_doc_1.png---(点击预览)
目录_doc_0.png---(点击预览)
目录.doc---(点击预览)
版滚轴.gif---(点击预览)
版滚轴.dwg---(点击预览)
爆炸图_pdf.png---(点击预览)
爆炸图.pdf---(点击预览)
机械加工工艺过程卡片_doc_2.png---(点击预览)
机械加工工艺过程卡片_doc_1.png---(点击预览)
机械加工工艺过程卡片_doc_0.png---(点击预览)
机械加工工艺过程卡片.doc---(点击预览)
开题报告和文献综述_doc_2.png---(点击预览)
开题报告和文献综述_doc_1.png---(点击预览)
开题报告和文献综述_doc_0.png---(点击预览)
开题报告和文献综述.doc---(点击预览)
字数统计.gif---(点击预览)
套.gif---(点击预览)
套.dwg---(点击预览)
大齿轮.gif---(点击预览)
大齿轮.dwg---(点击预览)
偏心套.gif---(点击预览)
偏心套.dwg---(点击预览)
任务书_doc_1.png---(点击预览)
任务书_doc_0.png---(点击预览)
任务书.doc---(点击预览)
三维图_pdf.png---(点击预览)
三维图.PDF---(点击预览)
三维图_pdf.txt
任务书_doc.txt
开题报告和文献综述_doc.txt
机械加工工艺过程卡片_doc.txt
爆炸图_pdf.txt
目录_doc.txt
说明书_doc.txt
外文翻译
压缩包内文档预览:
预览图 预览图 预览图 预览图 预览图 预览图
编号:124533650    类型:共享资源    大小:6.98MB    格式:ZIP    上传时间:2021-04-29 上传人:好资料QQ****51605 IP属地:江苏
45
积分
关 键 词:
曲面 印刷机 自动 机构 设计 cad 图纸 文档 全套 资料
资源描述:

喜欢这套资料就充值下载吧。。。资源目录里展示的都可在线预览哦。。。下载后都有,,请放心下载,,文件全都包含在内,,【有疑问咨询QQ:1064457796 或 1304139763】

内容简介:
英文原文:英文原文:PLCs -Past, Present and FutureJiahao WangEveryone knows theres only one constant in the technology world, and thatschange. 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 awide range of industries.At heart, the PLC is an industrialized computer programmed with highlyspecialized languages, and it continues to benefit from technological advances in thecomputer and information technology worlds. The most prominent of which isminiaturization and communications.1 The Shrinking PLCWhen the PLC was first introduced, its size was a major improvement - relativeto the hundreds of hard-wired relays and timers it replaced. A typical unit housing aCPU and I/O was roughly the size of a 19 television set. Through the 1980s and early1990s, modular PLCs continued to shrink in footprint while increasing in capabilitiesand performance (see Diagram 1 for typical modular PLC configuration).In recent years, smaller PLCs have been introduced in the nano and micro classesthat offer features previously found only in larger PLCs. This has made specifying alarger 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 replace stand-alone process controllers inmany applications, due to their ability to perform functions of motion control, dataacquisition, RTU (remote telemetry unit) and even some integrated HMI (humanmachine interface) functions. Previously, these functions often required their ownpurpose-built controllers and software, plus a separate PLC for the discrete controland interlocking.2 The Great CommunicatorPossibly the most significant change in recent years lies in the communicationsarena. In the 1970s Modiconintroduction of Modbus communications protocolallowed PLCs to communicate over standard cabling. This translates to an ability toplace PLCs in closer proximity to real world devices and communicate back to othersystem controls in a main panel.In the past 30 years we have seen literally hundreds of proprietary and standardprotocols developed, each with their own unique advantages.Todays PLCs have to bedata compilers and information gateways. They have to interface with bar codescanners and printers, as well as temperature and analog sensors. They need multipleprotocol support to be able to connect with other devices in the process. Andfurthermore, they need all these capabilities while remaining cost-effective and simpleto program.Another primary development that has literally revolutionized the way PLCs areprogrammed, communicate with each other and interface with PCs for HMI, SCADAor DCS applications, came from the computing world.Use of Ethernet communications on the plant floor has doubled in the past fiveyears. While serial communications remain popular and reliable, Ethernet is fastbecoming the communications media of choice with advantages that simply cant beignored, such as: * Network speed. * Ease of use when it comes to the setup andwiring. * Availability of off-the-shelf networking components. * Built-incommunications setups.3 Integrated Motion ControlAnother responsibility the PLC has been tasked with is motion control. Fromsimple open-loop to multi-axis applications, the trend has been to integrate thisfeature into PLC hardware and software.There are many applications that require accurate control at a fast pace, but notexact precision at blazing speeds. These are applications where the stand-alone PLCworks well. Many nano and micro PLCs are available with high-speed countingcapabilities and high-frequency pulse outputs built into the controller, making them aviable solution for open-loop control.The one caveat is that the controller does not know the position of the outputdevice during the control sequence. On the other hand, its main advantage is cost.Even simple motion control had previously required an expensive option module, andat times was restricted to more sophisticated control platforms in order to meet systemrequirements.More sophisticated motion applications require higher-precision positioninghardware and software, and many PLCs offer high-speed option modules thatinterface with servo drives. Most drives today can accept traditional commands fromhost (PLC or PC) controls, or provide their own internal motion control. The trendhere is to integrate the motion control configuration into the logic controllerprogramming software package.4 Programming LanguagesA facet of the PLC that reflects both the past and the future is programminglanguage. The IEC 61131-3 standard deals with programming languages and definestwo graphical and two textual PLC programming language standards: * Ladder logic(graphical). * Function block diagram (graphical). * Structured text(textual).Instruction list (textual).This standard also defines graphical and textual sequential function chartelements to organize programs for sequential and parallel control processing. Basedon the standard, many manufacturers offer at least two of these languages as optionsfor programming their PLCs. Ironically, approximately 96 percent of PLC usersrecently still use ladder diagrams to construct their PLC code. It seems that ladderlogic continues to be a top choice given its performed so well for so long.5 Hardware PlatformsThe modern PLC has incorporated many types of Commercial off the Shelf(COTS) technology in its CPU. This latest technology gives the PLC a faster, morepowerful processor with more memory at less cost. These advances have also allowedthe PLC to expand its portfolio and take on new tasks like communications, datamanipulation and high-speed motion without giving up the rugged and reliableperformance expected from industrial control equipment.New technology has also created a category of controllers called ProgrammableAutomation Controllers, or PACs. PACs differ from traditional PLCs in that theytypically utilize open, modular architectures for both hardware and software, using defacto standards for network interfaces, languages and protocols. They could beviewed as a PC in an industrial PLC-like package.6 The FutureA 2005 PLC Product Focus Study from Reed Research Group pointed out factorsincreasingly important to users, machine builders and those making the purchasingdecisions. The top picks for features of importance were.6.1 The ability to network, and do so easily.Ethernet communications is leading the charge in this realm. Not only are newprotocols surfacing, but many of the industry de facto standard serial protocols thathave been used for many years are being ported to Ethernet platforms. These includeModbus (ModbusTCP), DeviceNet (Ethernet/IP) and Profibus (Profinet). Ethernetcommunication modules for PLCs are readily available with high-speed performanceand flexible protocols. Also, many PLC CPUs are now available with Ethernet portson board, saving I/O slot space. PLCs will continue to develop more sophisticatedconnectivity to report information to other PLCs, system control systems, dataacquisition (SCADA) systems and enterprise resource planning (ERP) systems.Additionally, wireless communications will continue to gain popularity.6.2 The ability to network PLC I/O connections with a PC.The same trends that have benefited PLC networking have migrated to the I/Olevel. Many PLC manufacturers are supporting the most accepted fieldbus networks,allowing PLC I/O to be distributed over large physical distances, or located where itwas previously considered nearly impossible. This has opened the door for personalcomputers to interface with standard PLC I/O subsystems by using interface cards,typically supplied by the PLC manufacturer or a third party developer. Now thesechallenging locations can be monitored with today a PC. Where industrial-gradecontrol engines are not required, the user can take advantage of more advancedsoftware packages and hardware flexibility at a lower cost.6.3 The ability to use universal programming software for multipletargets/platforms.In the past it was expected that an intelligent controller would be complex toprogram. That is no longer the case. Users are no longer just trained programmers,such as design engineers or systems integrators, but end-users who expecteasier-to-use software in more familiar formats. The Windows-based look and feelthat users are familiar with on their personal computers have become the mostaccepted graphical user interface
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
提示  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
关于本文
本文标题:曲面印刷机版辊及自动对版机构设计【含6张cad图纸+文档全套资料】
链接地址:https://www.renrendoc.com/paper/124533650.html

官方联系方式

2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   
关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

网站客服QQ:2881952447     

copyright@ 2020-2025  renrendoc.com 人人文库版权所有   联系电话:400-852-1180

备案号:蜀ICP备2022000484号-2       经营许可证: 川B2-20220663       公网安备川公网安备: 51019002004831号

本站为文档C2C交易模式,即用户上传的文档直接被用户下载,本站只是中间服务平台,本站所有文档下载所得的收益归上传人(含作者)所有。人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私,请立即通知人人文库网,我们立即给予删除!