关于PLC控制系统设计的外文翻译.doc
《关于PLC控制系统设计的外文翻译.doc》由会员分享,可在线阅读,更多相关《关于PLC控制系统设计的外文翻译.doc(20页珍藏版)》请在咨信网上搜索。
1、 本科毕业设计(论文)外文翻译 ( 届 ) 题 目: 关于xxxPLC控制系统设计 分 院: 电气工程与自动化学院 专 业: 电气工程及其自动化 班 级: 姓 名: 学 号: 指导老师: 完成日期: 12月 原文: Introductions to PLC and Intelligent Control Katsuhiko Ogata A PLC (i.e. Programmable Logic Controller) is a device that was invented to replace the necessary sequential relay circuits for mac
2、hine control. The PLC works by looking at its inputs and depending u state, turning on/off its outputs. The user enters a program, usually via software or programmer, t desired results. PLCs are used in many “real world” applications. If there is industry present, chances are good that there is a PL
3、C present. If you are involved in machining, packaging, material handling, automated assembly or countless other industries, you are probably already using them. If you are not, you are wasting time. Almost any application that needs some type of electrical control has a need for a PLC. For example,
4、 lets assume that when a switch turns on we want to turn a solenoid on for 5 seconds a then turn it off regardless of how long the switch is on for. We can do this with a simple externa what if the process included 10 switches and solenoids? We would need 10 external timers. What if the process also
5、 needed to count how many times the switch individually turned on? We need a lot of e counters. As you can see, the bigger the process the more of a need we have for a PLC. We can simply progrPLC to count its inputs and turn the solenoids on for the specified time. We will take a look at what is con
6、sidered to be the “top 20” PLC instructions. It can be safely estimated that with a firm understanding of these instructions one can solve more than 80% of the applications in existence. Thats right, more than 80%! Of course well learn more than just these instructions to hel you solve almost ALL yo
7、ur potential PLC applications. The PLC mainly consists of a CPU, memory areas, and appropriate circuits to receive input/outpu as shown in Fig.1. We can actually consider the PLC to be a box full of hundreds or thousands of relays, counters, timers and data storage locations. Do these counters, time
8、rs, etc. really exist? No, they don “physically” exist but rather they are simulated and can be considered software counters, timers, et internal relays are simulated through bit locations in registers. Fig.1 The structure of PLC What does each part do? INPUT RELAYS-(contacts) These are connected to
9、 the outside world. They physically exist and receive signals from switches, sensors, etc. Typically they are not relays but rather they are tran. INTERNAL UTILITY RELAYS-(contacts) These do not receive signals from the outside world nor dothey physically exist. They are simulated relays and are wha
10、t enables a PLC to eliminate external reare also some special relays that are dedicated to performing only one task. Some are always on whare always off. Some are on only once during power-on and are typically used for initializing datstored. COUNTERS-These again do not physically exist. They are si
11、mulated counters and they can be programmed to count pulses. Typically these counters can count up, down or both up and down. Since tsimulated, they are limited in their counting speed. Some manufacturers also include high-speed couare hardware based. We can think of these as physically existing. Mo
12、st times these counters can count up, down or up and down. TIMERS-These also do not physically exist. They come in many varieties and increments. The most common type is an on-delay type. Others include off-delay and both retentive and non-retentive types. Increments vary from 1ms through 1s. OUTPUT
13、 RELAYS-(coils) These are connected to the outside world. They physically exist and son/off signals to solenoids, lights, etc. They can be transistors, relays, or triacs depending upon the model chosen. DATA STORAGE-Typically there are registers assigned to simply store data. They are usually tempor
14、ary storage for math or data manipulation. They can also typically be used to store data whenremoved from the PLC. Upon power-up they will still have the same contents as before power was remVery convenient and necessary! A PLC works by continually scanning a program. We can think of this scan cycle
15、 as consisting of 3 important steps, as shown in Fig.2. There are typically more than 3 but we can focus on the importannot worry about the others. Typically the others are checking the system and updating the current internal counter and timer values. Fig.2 The work process of PLC Step 1-CHECK INPU
16、T STATUS-First the PLC takes a look at each input to determine if it is on or oother words, is the sensor connected to the first input on? How about the second input? How about tthird It records this data into its memory to be used during the next step. Step 2-EXECUTE PROGRAM-Next the PLC executes y
17、our program one instruction at a time. Maybe your program said that if the first input was on then it should turn on the first output. Since it already knows which inputs are on/off from the previous step, it will be able to decide wheoutput should be turned on based on the state of the first input.
18、 3 It will store the execution results for use latduring the next step. Step 3-UPDATE OUTPUT STATUS-Finally the PLC updates the status of the outputs. It updates the outputs based on which inputs were on during the first step and the results of executing your progthe second step. Based on the exampl
19、e in step 2 it would now turn on the first output because thewas on and your program said to turn on the first output when this condition is true. After the third step the PLC goes back to step one and repeats the steps continuously. One scdefined as the time it takes to execute the 3 steps listed a
20、bove. Thus a practical system is controlspecified operations as desired. Intelligence and intelligent systems can be characterized in a number of ways and along a number of dimensions. There are certain attributes of intelligent systems, common in many definitions, which are of particular interest t
21、o the control community. In the following, several alternative definitions and certain essential characteristics of inteare first discussed. A brief working definition of intelligent systems that captures their common chis then presented. In more detail, we start with a rather general definition of
22、intelligent systelevels of intelligence, and we explain the role of control in intelligent systems and outline seve definitions. We then discuss adaptation and learning, autonomy and the necessity for efficient com structures in intelligent systems, to deal with complexity. We conclude with a brief
23、working charact intelligent (control) systems. We start with a general characterization of intelligent systems: An intelligent system has the ability to act appropriately in an uncertain environment, where an appropriate action is that which increases the probability of success, and success is the a
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 关于 PLC 控制系统 设计 外文 翻译
1、咨信平台为文档C2C交易模式,即用户上传的文档直接被用户下载,收益归上传人(含作者)所有;本站仅是提供信息存储空间和展示预览,仅对用户上传内容的表现方式做保护处理,对上载内容不做任何修改或编辑。所展示的作品文档包括内容和图片全部来源于网络用户和作者上传投稿,我们不确定上传用户享有完全著作权,根据《信息网络传播权保护条例》,如果侵犯了您的版权、权益或隐私,请联系我们,核实后会尽快下架及时删除,并可随时和客服了解处理情况,尊重保护知识产权我们共同努力。
2、文档的总页数、文档格式和文档大小以系统显示为准(内容中显示的页数不一定正确),网站客服只以系统显示的页数、文件格式、文档大小作为仲裁依据,平台无法对文档的真实性、完整性、权威性、准确性、专业性及其观点立场做任何保证或承诺,下载前须认真查看,确认无误后再购买,务必慎重购买;若有违法违纪将进行移交司法处理,若涉侵权平台将进行基本处罚并下架。
3、本站所有内容均由用户上传,付费前请自行鉴别,如您付费,意味着您已接受本站规则且自行承担风险,本站不进行额外附加服务,虚拟产品一经售出概不退款(未进行购买下载可退充值款),文档一经付费(服务费)、不意味着购买了该文档的版权,仅供个人/单位学习、研究之用,不得用于商业用途,未经授权,严禁复制、发行、汇编、翻译或者网络传播等,侵权必究。
4、如你看到网页展示的文档有www.zixin.com.cn水印,是因预览和防盗链等技术需要对页面进行转换压缩成图而已,我们并不对上传的文档进行任何编辑或修改,文档下载后都不会有水印标识(原文档上传前个别存留的除外),下载后原文更清晰;试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓;PPT和DOC文档可被视为“模板”,允许上传人保留章节、目录结构的情况下删减部份的内容;PDF文档不管是原文档转换或图片扫描而得,本站不作要求视为允许,下载前自行私信或留言给上传者【天****】。
5、本文档所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用;网站提供的党政主题相关内容(国旗、国徽、党徽--等)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。
6、文档遇到问题,请及时私信或留言给本站上传会员【天****】,需本站解决可联系【 微信客服】、【 QQ客服】,若有其他问题请点击或扫码反馈【 服务填表】;文档侵犯商业秘密、侵犯著作权、侵犯人身权等,请点击“【 版权申诉】”(推荐),意见反馈和侵权处理邮箱:1219186828@qq.com;也可以拔打客服电话:4008-655-100;投诉/维权电话:4009-655-100。