1. 有个农村叫张家庄，张家庄有个张木匠。张木匠有个好老婆，外号叫“小飞娥”。小飞娥生了个女儿叫艾艾。（顶真anadiplosis）（赵树理：《登记》）
2. 在中国一提到孔子，上至白发苍苍的老人，下至天真幼稚的顽童，无人不知，无人不晓，人们为了纪念他，在许多地方都建有祭祀他的寺庙，天津也不例外。
3.素有祖国南大门之称的广州火车站是华南地区最大的铁路客运站，比邻港澳和深圳、珠海、汕头经济特区，担负京广、广深、广肇铁路繁重的旅客运输工作。车站有7个站台、66股道、6候车室，还有酒楼、商场、旅店等服务设施，为不同层次的旅客提供各种优质、完善的服务，是我国第一个多功能的新型铁路客运站。
1.There was a village called Zhangjia Village, where lived Carpenter
Zhang, who had a good wife, nicknamed Little Moth, who gave birth to a girl called Ai’ai.
2. Confucius is a household name in China. Temples in memory of him could be found everywhere in China and Tianjin is no exception.
3. Guangzhou Railway Station Known as the southern gateway is the largest Railway Passenger Station in southern China, near Hong Kong, Macao and Shenzhen, Zhuhai, Shantou Special Economic Zone, takes Beijing-Guangzhou, Guangzhou-Shenzhen, and Guangzhou-Zhaoqing railway passenger transport heavy work. There are 7 platforms, 66 tracks, 6 waiting-rooms, and Restaurants, shopping malls, hotels and other
service facilities, which provide passengers with a variety of quality, perfect service. It is our first multi-functional railway passenger station.
具体分析
一、顶真
（一）什么是顶真
顶真也也叫顶针、联珠、蝉联、连环等。它是用上句结尾的词语作下句的开头，使相邻的词句首尾相蝉联，上递下接的修辞手法。其语言模式是“甲——乙，乙——丙，丙——丁……”。例如：
牵衣顿足拦道哭，哭声直上干云霄。（杜甫《兵车行》
召之即来，来之能战，战之能胜。
（二）顶真的类型
根据不同的标准，顶真可以分为不同的类型。
1、根据顶真部分有没有其他词语间隔，顶真可以分为直接顶真和间接顶真两类。
（1）直接顶真
直接顶真是顶真部分没有其他词语隔开的顶真。
（2）间接顶真
间接顶真，指顶真部分有其他词语间隔的顶真。
2、根据顶真的语言单位分，顶真可以分为词语的顶真和句子的顶真两类。
（1）词语的顶真
词语的顶真，就是词与词、短语与短语的顶真。
（2）句子的顶真
3、按顶真格出现的多少划分，顶真可以分为单联和串联两种。
（1）单联
单联，就是只有上下两个语言单位格式首尾蝉联。
（2）串联
串联就是三个或三个以上的语言格式首尾相连。
（三）顶真的作用
顶真在语言形式上有前顶后接、首尾蝉联的特点，形成了它在语言表达上的独特风格。顶真最突出的修辞作用是能清楚地反映事物的内在联系，阐明事物相互间的辨证关系。各种文体恰当地运用顶真都会收到明显的修辞效果。概括起来有以下三点：
1、运用于说理，准确严密。
2、用于叙事，条理清楚。
3、用于抒情，格调清新。
（四）顶真的运用
运用顶真应注意以下两点：
1、作顶真的事物要有必然的联系，确有衔接关系，不能生拼硬凑，搞文字游戏。
2、首尾相连的词语在形式和意义上要完全相同，只有这样，才能产生环环相扣的气势。
这是一句典型的汉语表达：采用了重复、对仗、四宇格，词藻
优美，若将该句不作处理，译为英文，按英文读者思维方式和.
这句话的意思无非是想说明孔子在中国是一位家喻户晓的名人。由于汉语注重形象思维，惯于将事物具象化，作者在“老人”和“顽童”之前分别添加了“白发苍苍”和“天真幼稚”这两个四字词；出于形式对称和音节和谐的考虑，作者又同时运用了“无人不知”和“无人不晓”这两个四字结构，造成了词义上的重复。如果译者将这句话中的四字格统统照直译出，则译文在英美读者看来不仅没有文采可言，反而拖沓冗余。这种差异是汉族人和英美人不同思维模式和审美心理造成的。西方人非常注重逻辑思维，英语就是一种非常严谨、理性的语言。英语行文尽管也有其华美精致的一面，但这种华丽的文采多建立在语言晓畅、逻辑清楚的基础之上，文字的堆砌和意义的繁复是英语文章的大忌
(3）他决心洗心革面，脱胎换骨。
He is determined to turn over a new leaf.
（4）本店货色齐全，品种多样，任君挑选。
We have a good assortment of goods to choose from.
例3中的“洗心革面”和“脱胎换骨”都具有“彻底改变旧有面目，重新做人”之意，如果重复译出反而累赘。例4的译者不仅将语义重叠的“货色齐全”和“品种多样”合译为have a good assortment of goods，而且改变了汉语原文的句式结构，使译文紧凑自然。
（5）花园里面是人间的乐园，有的是吃不了的大米白面，穿不完的绫罗绸缎，花不完的金银财宝。
（周而复《上海的早晨》）
The garden was a paradise on earth, with more food and clothes than could be consumed and more money than could be spent.
原文中的“大米白面”、“绫罗绸缎”、“金银财宝”指的就是“吃的”、“穿的”和“用的”，译者最好舍弃这些四字成语重叠堆砌的字面意义，直接传递其指称意义，即food、clothes和money。这样的处理使
译文简洁明了，符合英语的行文习惯。
（6）建立办事高效、运转协调、行为规范的行政管理体系。
a. To set up an administrative system with high efficiency in work, coordination in operation and standardization in behavior.
b. To establish a high efficient, well-coordinated and standardized administrative system.
（贾文波《汉英时文翻译》）
译文a“忠实”地对原文中的四字排比结构进行了字字对应式的翻译，但译文表达松散，行文也失之地道，是典型的中式英语。有鉴于此，译文b摆脱了四字结构的形式束缚，去除了原文中“办事”、“运转”、“行为”等纯粹为达到行文对称而添加的词语，用简洁的英文传递出原文的核心思想，即“建立高效、协调、规范的行政管理体系”。
（7）进入桂花公园，阵阵桂香扑鼻而来。满树金花，芳香四溢的金桂；花白如雪、香气扑鼻的银桂；红里透黄，花多味浓的紫砂桂；花色似银、季季有花的四季桂，竞相开放，争妍媲美。
The Park of Sweet Osmanthus is noted for its profusion of osmanthus trees. Flowers from these trees in different colors are in full bloom which pervade the whole garden with the fragrance of their blossoms.
这篇介绍桂花节的宣传材料用了许多四字词语，形象生动地描绘出公园里各色各样的桂花争奇斗艳的景象。这样的表达方式符合中国人的行文习惯和审美情趣，但宣传材料不是科普材料，不必将不同桂花的颜色与生长习性一一译出。况且，如果译文亦步亦趋，会变得累赘而夸张。因此，译者删去了原文中略显浮华的四字词语，概述性地描述了花开满园，香气四溢的景象，流畅地在译文中传递出了原文中最重要的信息。
Exploring Filipino School Counselors’ Beliefs about Learning Allan B. I. Bernardo [Abstract] School reform efforts that focus on student learning require school counselors to take on important new roles as advocates of student learning and achievement.But how do school counselors understand the process of learning? In this study, we explore the learning beliefs of 115 Filipino school counselors who indicated their degree of agreementwith 42 statements about the process of learning and the factors thatinfluence this process.A principal components analysis of the responses to the 42 statements suggested three factors:(F1)social-cognitive constructivist beliefs, (F2) teacher-curriculum-centered behaviorist beliefs,and (F3) individual difference factors.The preliminary results are briefly discussed in terms of issues related to how Filipino school counselors’ conceptions of learning may guide their strategies for promoting student learning and achievement. [Key words]beliefs about learning, conceptions of learning, school counselors, student learning, Philippines School reform efforts in different parts of the world have focusedon students’learning. In particular,most school improvement programsnow aim to ensure that students acquire the high-level knowledge and skills that help them to thrive in today’s highly competitive globaleconomy (e.g., Lee & Williams, 2006). I n this regard, school reform programs draw from various contemporary theories and research on learning (e.g.,Bransford,Brown, & Cocking, 1999; Lambert & McCombs, 1998).The basic idea is that all school improvement efforts should be directed at ensuring students achieve high levels of learning or attainment of well-defined curricular objectives and standards.For example, textbooks (Chien & Young, 2007), computers and educational technology (Gravoso, 2002; Haertnel & Means, 2003;Technology in Schools Task Force, 2003), and educational assessment systems (Black & Wiliam2004; Cheung & Ng, 2007; Clark, 2001; Stiggins, 2005) are being reconsidered as regards how they can effectively provide scaffolds and resources for advancing student learning. Likewise,the allocation and management of a school’s financial resources are assessed in terms ofwhether these are effectively mobilized and utilized towards improving student learning (Bolam, 2006; Chung & Hung, 2006; Retna, 2007). In this regard, some advocates have also called for an examination of the role of school counselors in these reform efforts (Herr, 2002). Inthe United States, House and Hayes (2002) challenged school counselors to take proactive leadership roles in advocating for the success of all
https://www.doczj.com/doc/43700135.html,/finance/company/consumer.html Consumer finance company The consumer finance division of the SG group of France has become highly active within India. They plan to offer finance for vehicles and two-wheelers to consumers, aiming to provide close to Rs. 400 billion in India in the next few years of its operations. The SG group is also dealing in stock broking, asset management, investment banking, private banking, information technology and business processing. SG group has ventured into the rapidly growing consumer credit market in India, and have plans to construct a headquarters at Kolkata. The AIG Group has been approved by the RBI to set up a non-banking finance company (NBFC). AIG seeks to introduce its consumer finance and asset management businesses in India. AIG Capital India plans to emphasize credit cards, mortgage financing, consumer durable financing and personal loans. Leading Indian and international concerns like the HSBC, Deutsche Bank, Goldman Sachs, Barclays and HDFC Bank are also waiting to be approved by the Reserve Bank of India to initiate similar operations. AIG is presently involved in insurance and financial services in more than one hundred countries. The affiliates of the AIG Group also provide retirement and asset management services all over the world. Many international companies have been looking at NBFC business because of the growing consumer finance market. Unlike foreign banks, there are no strictures on branch openings for the NBFCs. GE Consumer Finance is a section of General Electric. It is responsible for looking after the retail finance operations. GE Consumer Finance also governs the GE Capital Asia. Outside the United States, GE Consumer Finance performs its operations under the GE Money brand. GE Consumer Finance currently offers financial services in more than fifty countries. The company deals in credit cards, personal finance, mortgages and automobile solutions. It has a client base of more than 118 million customers throughout the world
高速视频处理系统中的信号完整性分析 摘要：结合高速DSP图像处理系统讨论了高速数字电路中的信号完整性问题，分析了系统中信号反射、串扰、地弹等现象破坏信号完整性的原因，通过先进IS工具的辅助设计，找出了确保系统信号完整性的具体方法。 关键词：高速电路设计信号完整性 DSP系统 深亚微米工艺在IC设计中的使用使得芯片的集成规模更大、体积越来越小、引脚数越来越多；由于近年来IC工艺的发展，使得其速度越来越高。从而，使得信号完整性问题引起电子设计者广泛关注。 在视频处理系统中，多维并行输入输出信号的频率一般都在百兆赫兹以上，而且对时序的要求也非常严格。本文以DSP图像处理系统为背景，对信号完整性进行准确的理论分析，对信号完整性涉及的典型问题[1]——不确定状态、传输线效应、反射、串扰、地弹等进行深入研究，并且从实际系统入手，利用IS仿真软件寻找有效的途径，解决系统的信号完整性问题。 1 系统简介 为了提高算法效率，实时处理图像信息，本图像处理系统是基于DSP+FPGA结构设计的。系统由SAA7111A视频解码器、TI公司的TMS320C6701 DSP、Altera公司的EPlK50QC208 FPGA、PCI9054 PCI接口控制器以及SBRAM、SDRAM、FIFO、FLASH等构成。FPGA是整个系统的时序控制中心和数据交换的桥梁，而且能够对图像数据实现快速底层处理。DSP是整个系统实时处理高级算法的核心器件。系统结构框图如图1所示。 在整个系统中，PCB电路板的面积仅为15cm×l5cm，系统时钟频率高达167MHz，时钟沿时间为0．6ns。由于系统具有快斜率瞬变和极高的工作频率以及很大的电路密度，使得如何处理高速信号问题成为一个制约设计成功的关键因素。 2 系统中信号完整性问题及解决方案 2．1 信号完整性问题产生机理 信号的完整性是指信号通过物理电路传输后，信号接收端看到的波形与信号发送端发送的波形在容许的误差范围内保持一致，并且空间邻近的传输信号间的相互影响也在容许的范围之内。因此，信号完整性分析的主要目标是保证高速数字信号可靠的传输。实际信号总是存在电压的波动，如图2所示。在A、B两点由于过冲和振铃[2]的存在使信号振幅落入阴影部分的不确定区，可能会导致错误的逻辑电平发生。总线信号传输的情况更加复杂，任何一个信号发生相位上的超前或滞后都可能使总线上数据出错，如图3所示。图中，CLK为时钟信号，D0、D1、D2、D3是数据总线上的信号，系统允许信号最大的建立时间[1]为△t。在正常情况下，D0、D1、D2、D3信号建立时间△t1<△t，在△t时刻之后数据总线的数据已稳定，系统可以从总线上采样到正确的数据，如图3(a)所示。相反，当信号D1、D2、D3受过冲和振铃等信号完整问题干扰时，总线信号就发生
翻译技巧8 名词性从句的翻译 1. 主语从句 * 以what、whatever等代词引导的主语从句，一般可采用直译。 1）What really concerns us is when our order is ready for shipment. 真正让我们担心的是我们的订货什么时候可以准备装船。 2) Whatever you say cannot make us reduce our price any further. 不管你们怎么说，我们不能再减价了。 3) What you should pay attention to is that claim must be made within the term of validity stipulated in the contract. 必须注意的是，索赔必须在合同规定的有效期内提出。 * 以it为形式主语引导的主语从句，翻译较为灵活。 4) From what you say, it is possible that we have made some mistake in the delivery of the goods meant for you. 根据贵方的来函所述，我方有可能在为贵方备货发运时出了差错。 5) It has also been observed that in many countries it is difficult for a foreign company to obtain not only the import license, but also duty relief. 还应该注意到，外国公司在许多国家很难获得出口许可证及关税的减免。 6）It is a matter of regret that we do not have a stock of sufficient quantity to supply you at present. 本公司目前存货不足，无法满足向贵方的供货，这真是非常遗憾。
GRA VITY RETAINING?WALL 1. INTRODUCTION Retaining walls are structures used to provide stability for earth or other material where conditions disallow the mass to assume its natural slope, and are commonly used to hold back or support soilbanks,coal or ore piles, and water. Retaining walls are classified, based on the method of achieving stability, into six principal types (Fig.1). The gravity-wall depends upon its weight, as the name implies, for stability. The cantilever wall is a reinforced-concrete wall that utilizes cantilever action to retain the mass behind the wall from assuming a natural slope. Stability of this wall is partially achieved from the weight of soil on the heel portion of the base slab. A counterfort retaining wall is similar to a cantilever retaining wall, except that it is used where the cantilever is long or for very high pressures behind wall and has counterforts, which tie the wall and base together, built at intervals along the wall to reduce the bending moments and sheers. As indicated in Fig.1c, the counterfort is behind the wall and subjected to tensile forces. A buttressed retaining wall is similar to a counterfort wall, except that the bracing is in front of the wall and is in compression instead of tension. Two other types of walls not considered further are crib walls, which are built-up members of pieces of precast concrete, metal, or timber and are supported by anchor pieces embedded in the soil for stability, and semigravity walls, which are walls intermediate between a true gravity and a cantilever wall. (a)(b)(e)
（2012重庆卷，34）儿童早期的睡眠问题很有可能在他们长大的时候还会继续这一证据已经在数年研究后被发现了。 Evidence has been found through years of study that children’s early sleeping problems are likely to continue when they grow up. （2012天津卷，9）你在十字路口向左转还是向右转都没有关系，每条路都通向公园。 It doesn’t matter whether you turn right or left at the crossing ---both roads lead to the park. （2012四川卷，17）科学家研究人类大脑是如何运作来制作电脑的。 Scientists study how human brains work to make computers. （2012上海卷，34）善良通常是通过坦诚来实现的，这是个很有道理的想法。 There is much truth in the idea that kindness is usually served by frankness. （2012上海卷，38）--- 我们只有这个小书柜，那样可以么？ --- 不行的，我要找的是个更大更结实的东
西。 - We've only got this small bookcase. Will that do? - No, what I am looking for is something much bigger and stronger. （2012陕西卷，20）提供了有多大五个的课程，而且你可以选择任何一个最适合你的课程。 As many as five courses are provided, and you are free to choose whichever suits you best. （2012山东卷，25）在这个店里面，不管你是用现金支付还是信用卡支付都没有关系。 It doesn’t matter whether you pay by cash or credit card in this store. （2012全国卷I，24）根本不清楚总统能做什么来结束罢工。 It is by no means clear what the president can do to end the strike. （2012辽宁卷，34）不久前一天，那个新来者去图书馆找关于马克吐温的书。 The newcomer went to the library the other day and
文档简介 一，英语翻译经典文章之英文原稿二，中文翻译：这篇英语文章的最好翻译版本！不是俺说的，是俺老师说哒！！ 英文原稿Brian It seems my only request (“please, let me sleep”) is not clear enough, so I made this simple table that can help you when you’re in doubt. Especially during the night
中文翻译小子： 我只想好好地睡觉，你不明白吗？！所以，我做了这个简表。当你不知道怎么办时，特 别是在晚上的时候，你可以看看它。 具体情况行动指南 1，我正在睡觉禁止进入 2，你不确定我是否睡觉，你想搞清楚管你“鸟”事；禁止进入 3，你嗑了药，想奔向我的床你他妈的滚远点 4，你在youtube上看了一个超赞的视频，禁止进入；在脸书上把链接发给我想让我看看 5，就算第三次世界大战开始了管我屁事，他妈的别进来 6，你和你的基友们想和我“玩玩”抱歉，直男一枚。不要碰我的任何东西，门都别碰 7，你想整理我的房间我谢谢你了！我自己会打扫 8，普京宣布同性婚姻合法化终于等到“它”！还好你没放弃！还是不要来我房里！ 9，我不在家进我房间，想都别想 10，白天，我在家。你敲了门，我说“请进” 你可以进来了 福利放送！！
如果你已经看到了这里，那么说明你应该是英文爱好者哦。 下面有一些非常实用，我精心整理的英文资料，你一定用得到！快去看看吧！ 一，最常用英语翻译政治文体句型总结大全完美版 二，英文合同翻译最常用句型总结专业版 三，英语毕业论文提纲模板优秀完整详细无敌版
名词性从句翻译 宾语从句翻译： 1.妈妈经常告诉我an idle youth; a needy age. My mother used to tell me an idle youth; a needy age. 2.不要问你的国家能为你做什么；问你能为你的国家做什么。 Ask not /Don’t ask what your country can do for you; ask what you can do for your country. 3.我很纳闷为什么那么多女孩喜欢王俊凯. I wonder why so many girls are crazy about Wang Junkai. 4.我不知道他是否愿意给我一个机会。 I don’t know if he is willing to give me a chance. 5.你知道张弥曼是谁吗？ Do you know who Zhang Miman? 表语从句翻译： 1.我的愿望是我能成为一个土豪。（rich redneck/ tuhao） My wish is that I could be a tuhao. 2.问题是我怎样才能成为一个土豪。 The problem/thing/point is how I can become a tuhao. 3.事实是很多人想和土豪交朋友。 The fact is that plenty of people want to make friends with tuhaos. 4.那是因为土豪非常乐于帮助朋友。 That is because tuhaos are ready to help friends out. 5.他看起来像个屌丝。(loser/pleb) He looks as if he is/were a loser. 主语从句翻译: 1.习近平是president of China 是众所周知的。 That Xi Jinping is president of China is well-known. 2.那些恐怖分子所做的是没人性的。（terrorist，inhuman） What the terrorists did was inhuman. 3.中段考你能否考好取决于你现在是否努力学习。 Whether you can do well/ score high points in the mid-term exam depends on whether you are working hard now. 4.《最强大脑》为什么那么受欢迎正在被讨论。（“Super Brain”） Why “Super Brain” is so popular is under discussion. 5.如何才能快速减肥是我想知道的。 How can I lose weight quickly is what I want to know. 6.你来自哪里并不重要，重要的是你将去哪里。 What matters is not where you are from but where you are going. 同位语从句翻译： 1.宇宙起源于大爆炸的这个理论被广泛接受。 The theory that the universe began with a big bang is widely accepted.
南京师范大学泰州学院 英文翻译原文 年级： 2011级学号：12110330 姓名：申佳佳 系部：信息工程学院 专业：通信工程 题目：基于C51的数字测速仪设计与仿真 指导教师：焦蓬蓬 2015 年 4 月 5 日
Linux - Operating system of cybertimes Though for a lot of people , regard Linux as the main operating system to make u p huge work station group, finish special effects of " Titanic " make , already can be re garded as and show talent fully. But for Linux, this only numerous news one of. Rece ntly, the manufacturers concerned have announced that support the news of Linux to i ncrease day by day, users' enthusiasm to Linux runs high unprecedentedly too. Then, Linux only have operating system not free more than on earth on 7 year this piece wh at glamour, get the favors of such numerous important software and hardware manufa cturers as the masses of users and Orac le , Informix , HP , Sybase , Corel , Intel , Net scape , Dell ,etc. , OK? 1.The background of Linux and characteristic Linux is a kind of " free (Free ) software ": What is called free, mean users can o btain the procedure and source code freely , and can use them freely , including revise or copy etc.. It is a result of cybertimes, numerous technical staff finish its research a nd development together through Inte rnet, countless user is it test and except fault , c an add user expansion function that oneself make conveniently to participate in. As th e most outstanding one in free software, Linux has characteristic o f the following: (1)Totally follow POSLX standard, expand the network operating system of sup porting all AT&T and BSD Unix characteristic. Because of inheritting Unix outstandi ng design philosophy , and there are clean , stalwart , high-efficient and steady kernels , their all key codes are finished by Li nus Torvalds and other outstanding programmer s, without any Unix code of AT&T or Berkeley, so Linu x is not Unix, but Linux and Unix are totally compatible. (2)Real many tasks, multi-user's system, the built-in n etwork supports, can be with such seamless links as NetWare , Windows NT , OS/2 , Unix ,etc.. Network in various kinds of Unix it tests to be fastest in comparing and ass ess efficiency. Support such many kinds of files systems as FAT16 , FAT32 , NTFS , E x t2FS , ISO9600 ,etc. at the same time .
作为一部优秀的语录体散文集，《论语》以言简意赅、含蓄隽永的语言，记述了孔子的言论。《论语》中所记孔子循循善诱的教诲之言，或简单应答，点到即止;或启发论辩，侃侃而谈；富于变化，娓娓动人。 以下是《论语十则》的翻译。 子曰：「学而时习之，不亦说乎。有朋自远方来，不亦乐乎。人不知而不愠，不亦君子乎。」 Confucius said: "Isn’t it a pleasure to study and practice what you have learned? Isn’t it also great when friends visit from distant places? If people do not recognize me and it doesn’t bother me, am I not a Superior Man?" 子曰：「不患人之不己知，患不知人也。」 Confucius said: "I am not bothered by the fact that I am unknown. I am bothered when I do not know others." 子曰：「道之以政，齐之以刑，民免而无耻；道之以德，齐之以礼，有耻且格。」Confucius said: "If you govern the people legalistically and control them by punishment, they will avoid crime, but have no personal sense of shame. If you govern them by means of virtue and control them with propriety, they will gain their own sense of shame, and thus correct themselves." 子曰：「吾十有五而志于学，三十而立，四十而不惑，五十而知天命，六十而耳顺，七十而从心所欲，不逾矩。」 Confucius said: "At fifteen my heart was set on learning; at thirty I stood firm; at forty I had no more doubts; at fifty I knew the mandate of heaven; at sixty my ear was obedient; at seventy I could follow my heart’s desire without transgressing the norm." 子曰：「温故而知新，可以为师矣。」 Confucius said: "Reviewing what you have learned and learning anew, you are fit to be a teacher." 子曰：「君子不器。」 Confucius said: "The Superior Man is no utensil." 子贡问君子。子曰：「先行其言而后从之。」 Tzu Kung asked about the character of the Superior Man. Confucius said, "First he practices what he preaches and then he follows it." 子曰：「学而不思则罔，思而不学则殆。」 Confucius said: "To study and not think is a waste. To think and not study is dangerous."
Basic Control Actions and Industrial Automatic Control An automatic controller compares the actual value of the plant output with the desired value, determines the deviation, and produces a control signal which will reduce the deviation to zero or to a small value.The manner in which the automatic conroller produces the control signal is called the control action. Classifications of industrial automatic controllers Induetrial automatic controllers may be classified according to their control action as: ·two-position or on-off controllers; ·proportional controllers; ·integral controllers; ·proportional-plus-integral controllers; ·proportional-plus-derivative controllers; ·proportional-plus-derivative-plus-integral controllers. Most industrial automatic controllers use eletricity or pressurized fluid such as oil or air as power sources. Automatic controllers may also be classified according to the kind of power employed in the operation, such as pneumatic controllers, hydraulic controllers, or electronic controllers.What kind of controller to use must be decided by the nature of the plant and the operating conditions,including such considerations as safety, availability, reliability, accuracy, weight, and size? Elements of industrial automatic controllers An automatic controller must detect the actuating error signal, which is usually at a very low power level, and amplify it to a sufficiently high level. Thus, an amplifier is necessary. The output of an automatic controller is fed to a power device, such as a pneumatic motor or valve, a hydraulic motor, or an electric motor. The controller usually consists of an error detector and amplifier. The measuring element is a device that converts the output variable into another suitable variable, such as a displacement, pressure, or electric signal, which can be used for comparing the output to the reference input signal. This element is in the feedback path of the closed-loop system. The set point of the controller must be converted to a reference input of the same units as the feedback signal from the measuring element. The amplifier amplifies the power of the actuating error signal, which in turn operates the actuator. The actuator is an element which alters the input to the plant according to the control signal so that the feedback signal may be brought into correspondence with the reference input signal. Self-operated controllers In most industrial automatic controllers, separate units are used for the measuring element and for the actuator. In a very simple one, however, such as a self-operated controller, these elements are assembled in one unit. Self-operated controllers utilize power developed by the measuring element and are very simple and inexpensive. The set point is determined by the adjustment of the spring force. The controlled pressure is measured by the diaphragm. The actuating error signal is the net force acting on the diaphragm. Its position determines the valve opening. The operation of self-operated controller is as follows: Suppose that the output pressure is lower than the reference pressure, as determined by the set point. Then the downward spring force is greater than the upward pressure force, resulting in a downward movement of the diaphragm. This increases the flow rate and raises the output pressure.