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第一章第一篇sectiongTwo variables u(t) and i(t) are the most basic concepts in an electric circuit, they characterize the various relationships in an electric circuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。
the charge e on an electron is negative and equal in magnitude to 1.60210×10 19C, while a proton carries a positive charge of the same magnitude as the electron. The presence of equal numbers of protons and electrons leaves an atom neutrally charged. 我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。
我们还知道电子的电量是负的并且在数值上等于 1.602100×10-12C，而质子所带的正电量在数值上与电子相等。
质子和电子数量相同使得原子呈现电中性。
We consider the flow of electric charges. A unique feature offlow of negative charges, as Fig.l-1 illustrates. This convention was introduced by Benjamin Franklin (l706～l790), the American scientist and inventor. Although we now know that current in metallic conductors is due to negatively charged electrons, we will follow the universally accepted conventionthat current is the net flow of positive charges. Thus, Electriccurrent is the time rate of charge, measured in amperes (A).Mathematically, the relationship among current i , charge q , andtime t is 当我们把一根导线连接到某一电池上时(一种电动势源)，电荷被外力驱使移动；正电荷朝一个方向移动而负电荷朝相反的方向time in several ways that may be represented by different kindsof mathematical functions 我们通过方程（1－1）定义电流的方式表明电流不必是一个恒值函数，电荷可以不同的方式随时间而变化，这些不同的方式可用各种数学函数表达出来。
电气自动化专业英语（翻译1-3）第一部分：电子技术第一章电子测量仪表电子技术人员使用许多不同类型的测量仪器。
一些工作需要精确测量面另一些工作只需粗略估计。
有些仪器被使用仅仅是确定线路是否完整。
最常用的测量测试仪表有：电压测试仪，电压表，欧姆表，连续性测试仪，兆欧表，瓦特表还有瓦特小时表。
所有测量电值的表基本上都是电流表。
他们测量或是比较通过他们的电流值。
这些仪表可以被校准并且设计了不同的量程，以便读出期望的数值。
1．1安全预防仪表的正确连接对于使用者的安全预防和仪表的正确维护是非常重要的。
仪表的结构和操作的基本知识能帮助使用者按安全工作程序来对他们正确连接和维护。
许多仪表被设计的只能用于直流或只能用于交流，而其它的则可交替使用。
注意：每种仪表只能用来测量符合设计要求的电流类型。
如果用在不正确的电流类型中可能对仪表有危险并且可能对使用者引起伤害。
许多仪表被设计成只能测量很低的数值，还有些能测量非常大的数值。
警告：仪表不允许超过它的额定最大值。
不允许被测的实际数值超过仪表最大允许值的要求再强调也不过分。
超过最大值对指针有伤害，有害于正确校准，并且在某种情况下能引起仪表爆炸造成对作用者的伤害。
许多仪表装备了过载保护。
然而，通常情况下电流大于仪表设计的限定仍然是危险的。
1．2基本仪表的结构和操作许多仪表是根据电磁相互作用的原理动作的。
这种相互作用是通过流过导体的电流引起的（导体放置在永久磁铁的磁极之间）。
这种类型的仪表专门适合于直流电。
不管什么时候电流流过导体，磁力总会围绕导体形成。
磁力是由在永久磁铁力的作用下起反应的电流引起。
这就引起指针的移动。
导体可以制成线圈，放置在永久磁铁磁极之间的枢钮（pivot中心）上。
线圈通过两个螺旋型弹簧连在仪器的端子上。
这些弹簧提供了与偏差成正比的恢复力。
当没有电流通过时，弹簧使指针回复到零。
表的量程被设计来指明被测量的电流值。
线圈的移动（或者是指针的偏移）与线圈的电流值成正比。
自动化专业英语原文和翻译Title: Original Text and Translation of Automation Professional EnglishIntroduction:In the field of automation, it is essential to have a good command of professional English, as many resources and documents are written in English. In this article, we will explore the original text and translation of automation professional English, providing a comprehensive guide for those looking to improve their language skills in this area.1. Original Text and Translation of Automation Terminology1.1 The original text of automation terminology includes terms such as PLC (Programmable Logic Controller), HMI (Human-Machine Interface), and SCADA (Supervisory Control and Data Acquisition).1.2 The translation of these terms into other languages must be accurate and consistent to ensure clear communication in an international context.1.3 It is important for professionals in the automation industry to be familiar with these terms in both English and their native language to facilitate effective communication with colleagues and clients.2. Original Text and Translation of Automation Standards2.1 Automation standards, such as ISO 9001 and IEC 61131, are crucial for ensuring quality and safety in automation systems.2.2 Translating these standards accurately is essential to ensure compliance with regulations and best practices in different countries.2.3 Professionals in the automation industry should be well-versed in the original text of these standards and their translations to ensure the successful implementation of automation projects worldwide.3. Original Text and Translation of Automation Documentation3.1 Automation documentation, including user manuals, technical specifications, and maintenance guides, is often written in English.3.2 Translating this documentation accurately is essential to ensure that users and technicians can understand and operate automation systems effectively.3.3 Professionals in the automation industry should be proficient in both the original text and translated versions of documentation to facilitate training, troubleshooting, and maintenance of automation systems.4. Original Text and Translation of Automation Research Papers4.1 Research papers on automation topics are often published in English-language journals and conferences.4.2 Translating these papers accurately is crucial for sharing knowledge and advancements in the field of automation with a global audience.4.3 Professionals in the automation industry should be able to read and understand original research papers in English and be familiar with translations in other languages to stay informed about the latest developments in the field.5. Original Text and Translation of Automation Software5.1 Automation software, such as CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing) programs, often have interfaces and documentation in English.5.2 Translating this software accurately is essential for ensuring that engineers and technicians can use these tools effectively.5.3 Professionals in the automation industry should be proficient in both the original text and translated versions of automation software to maximize their productivity and efficiency in their work.Conclusion:In conclusion, having a good command of professional English in the field of automation is essential for effective communication, compliance with standards, and staying informed about the latest developments. By understanding the original text and translations of automation terminology, standards, documentation, research papers, and software, professionals in the industry can enhance their language skills and excel in their careers.。
自动化专业英语原文和翻译Automation in the Field of EngineeringIntroduction:Automation plays a crucial role in various industries, and the field of engineering is no exception. In this document, we will explore the importance of automation in engineering and its impact on various aspects of the industry. We will also provide a detailed analysis of the benefits and challenges associated with automation in engineering. Additionally, we will discuss the significance of specialized English language skills in the automation profession and provide a translated version of the content in Chinese.Importance of Automation in Engineering:Automation has revolutionized the engineering industry by enhancing productivity, efficiency, and accuracy. It involves the use of advanced technologies and systems to control and monitor various engineering processes. Automation enables engineers to streamline operations, reduce manual labor, and improve overall performance. It plays a vital role in areas such as manufacturing, construction, energy, transportation, and telecommunications.Benefits of Automation in Engineering:1. Increased Productivity: Automation eliminates repetitive and mundane tasks, allowing engineers to focus on more complex and strategic activities. This leads to increased productivity and faster project completion.2. Improved Efficiency: Automated systems can perform tasks more efficiently than humans, resulting in reduced errors and improved quality of work.3. Enhanced Safety: Automation reduces the risk of accidents and injuries by replacing manual labor with machines in hazardous environments.4. Cost Savings: By automating processes, companies can reduce labor costs, minimize waste, and optimize resource utilization, leading to significant cost savings.5. Better Decision-Making: Automation provides engineers with real-time data and analytics, enabling them to make informed decisions and optimize processes for better outcomes.Challenges of Automation in Engineering:1. Initial Investment: Implementing automation systems requires a significant upfront investment in technology, infrastructure, and training.2. Technological Complexity: Automation involves advanced technologies such as robotics, artificial intelligence, and machine learning, which require specialized knowledge and expertise to operate and maintain.3. Workforce Adaptability: Automation may lead to job displacement and require the workforce to acquire new skills to adapt to the changing industry landscape.4. Cybersecurity Risks: With increased reliance on interconnected systems, the risk of cyber threats and data breaches becomes a significant concern in automated engineering environments.Importance of Specialized English Language Skills in Automation:English language proficiency is crucial for professionals in the automation field due to the global nature of the industry. Engineers need to communicate effectively with colleagues, clients, and stakeholders from different countries. Additionally, technical documentation, research papers, and industry standards are often written in English. Proficiency in specialized English terminology related to automation is essential for clear and accurate communication.Translation in Chinese (简体中文翻译):工程自动化的重要性：自动化在各个行业中都发挥着重要作用，工程领域也不例外。
自动化专业英语原文和翻译Automation in the Manufacturing Industry: An OverviewIntroduction:Automation plays a crucial role in the manufacturing industry, revolutionizing production processes and enhancing efficiency. This article provides an in-depth analysis of the concept of automation in the manufacturing sector, highlighting its benefits, challenges, and future prospects. It also includes a translation of the text into English.Section 1: Definition and Importance of AutomationAutomation refers to the use of technology and machinery to perform tasks with minimal human intervention. In the manufacturing industry, automation is essential for streamlining operations, reducing costs, and improving product quality. It allows companies to achieve higher production rates, increased precision, and improved safety standards.Section 2: Benefits of Automation in Manufacturing2.1 Increased ProductivityAutomation enables manufacturers to produce goods at a faster rate, leading to increased productivity. With the use of advanced robotics and machinery, repetitive tasks can be performed efficiently, allowing workers to focus on more complex and creative aspects of production.2.2 Enhanced Quality ControlAutomated systems ensure consistency and accuracy in manufacturing processes, leading to improved product quality. By minimizing human error, automation reduces defects and variations, resulting in higher customer satisfaction and reduced waste.2.3 Cost ReductionAutomation helps in reducing labor costs by replacing manual work with machines and robots. Although initial investment costs may be high, long-term savings are significant due to increased efficiency and reduced dependence on human labor.2.4 Improved Workplace SafetyAutomation eliminates the need for workers to perform hazardous or physically demanding tasks. Robots and machines can handle tasks that pose risks to human health and safety, thereby reducing workplace accidents and injuries.2.5 Increased FlexibilityAutomated systems can be easily reprogrammed to adapt to changing production requirements. This flexibility allows manufacturers to respond quickly to market demands, introduce new products, and customize production processes.Section 3: Challenges in Implementing Automation3.1 Initial InvestmentImplementing automation requires substantial capital investment for purchasing and integrating machinery, software, and training. Small and medium-sized enterprises (SMEs) may face financial constraints in adopting automation technologies.3.2 Workforce AdaptationAutomation may lead to job displacement, as certain tasks previously performed by humans are now handled by machines. Companies need to provide training and re-skilling opportunities to ensure a smooth transition for their workforce.3.3 Technical ComplexityAutomation systems often involve complex integration of various technologies, such as robotics, artificial intelligence, and data analytics. Companies must have skilled personnel capable of managing and maintaining these systems effectively.Section 4: Future Trends in Automation4.1 Collaborative RobotsCollaborative robots, also known as cobots, are designed to work alongside humans, assisting them in tasks that require precision and strength. These robots can improve productivity and safety by working in close proximity to humans without the need for extensive safety measures.4.2 Internet of Things (IoT) IntegrationThe integration of automation systems with the Internet of Things allows for real-time monitoring and control of manufacturing processes. IoT enables seamless communication between machines, sensors, and data analytics platforms, leading to predictive maintenance and optimized production.4.3 Artificial Intelligence (AI)AI technologies, such as machine learning and computer vision, enable automation systems to learn and adapt to new situations. AI-powered robots can analyze data, make decisions, and perform complex tasks with minimal human intervention, revolutionizing the manufacturing industry.Conclusion:Automation has become an integral part of the manufacturing industry, offering numerous benefits such as increased productivity, enhanced quality control, cost reduction, improved workplace safety, and increased flexibility. While challenges exist, such as initial investment and workforce adaptation, the future of automation looks promising with the emergence of collaborative robots, IoT integration, and artificial intelligence. Embracing automation technologies will undoubtedly pave the way for a more efficient and competitive manufacturing sector.Translation:自动化在制造业中的应用：概述简介：自动化在制造业中扮演着重要的角色，革新了生产过程，提高了效率。
自动化专业英语第四版课文翻译Unit 1现在工业电子系统使用的是被称为晶体管的装置。
每一类型的晶体管有区别于其他晶体管的不同特点和操作条件。
在讨论的第一部分，我们来关注双极性晶体管。
从结构上看，这个晶体管被描述为双极性的，是因为它有两个不同的电流载体极性。
空穴是阳极电流载体，而电子是阴极电流载体。
这两个不同性质的半导体晶体通过一个公共部分连接在一起。
这个装置的结构类似于两个二极管背靠背连接，其中一个晶体充当另外两个晶体的公共部分。
中间的材料通常被做得比外面的两片都要薄。
图1.1表示的是此晶体管的结构，原件名称，和不同双极性晶体管的语义符号。
一个双极性晶体管主要被用做放大器来限制流经它的电流。
电流从电源流入发射极，经过基极，再流出集电极。
集电极的电流量通常被定义为晶体管的输出量。
集电极电流由基极电流中的一小部分控制。
这个关系被描述为电流增量或β。
数学表达式如下：电流增量=集电极电流：基极电流。
公式中希腊字母△表示变化的值。
它用来表示当有交流输入时晶体管的响应。
这种类型的状态被称为动态特性。
公式中的△的省略部分表示直流或静态工作条件。
所有从发射极进入晶体管的电流被定义为发射极电流。
集电极电流Ic通常小于Ie。
Ie和Ic的不同归因于基极电流。
从数学角度看，Ib=Ie-IcUnit 2一个运算放大器的内部结构相当复杂，常常包含大量的分立元件。
一个运算放大器的使用者通常不需要关心它的内部结构。
然而，对于如何理解内部电子电路的完成却是有所帮助的。
这就允许使用者来观察设备是如何工作的，以及表明它作为一个功能单元的一些局限性。
运算放大器的内部电子线路可以被分为三个功能单元。
图1.7即是一个运算放大器内部功能的简图。
注意每一个功能都被附在一个三角形内。
电子图表中用三角形来表示放大功能。
这个简图显示了运算放大器有三个基本的放大功能。
这些功能一般叫作放大级。
一个放大级包含一或更多有源器件，所有相联元件需实现放大。
第一阶段或一个运算放大器的输入常常是一个差动放大器。
自动化专业英语原文和翻译引言概述：自动化专业是现代工程技术领域中的重要学科，涵盖了自动控制系统、机器人技术、工业自动化等多个方面。
在学习和实践中，掌握和理解自动化专业的英文术语和翻译是非常重要的。
本文将从五个大点出发，详细阐述自动化专业英语原文和翻译的相关内容。
正文内容：1. 自动控制系统（Automatic Control System）1.1 控制器（Controller）1.2 传感器（Sensor）1.3 执行器（Actuator）1.4 反馈（Feedback）1.5 稳定性（Stability）2. 机器人技术（Robotics）2.1 机器人（Robot）2.2 机械臂（Manipulator）2.3 传感器（Sensor）2.4 视觉系统（Vision System）2.5 自主导航（Autonomous Navigation）3. 工业自动化（Industrial Automation）3.1 自动化生产线（Automated Production Line）3.2 人机界面（Human-Machine Interface）3.3 传感器网络（Sensor Network）3.4 电气控制（Electrical Control）3.5 数据采集（Data Acquisition）4. 自动化软件（Automation Software）4.1 PLC编程（PLC Programming）4.2 HMI设计（HMI Design）4.3 数据分析（Data Analysis）4.4 模拟仿真（Simulation）4.5 系统集成（System Integration）5. 自动化工程（Automation Engineering）5.1 项目管理（Project Management）5.2 自动化设计（Automation Design）5.3 系统调试（System Debugging）5.4 故障诊断（Fault Diagnosis）5.5 性能优化（Performance Optimization）总结：综上所述，自动化专业英语原文和翻译是自动化工程师必备的技能之一。
自动化专业英语原文和翻译Automation in the Field of EngineeringIntroduction:Automation plays a crucial role in various industries, including the field of engineering. It involves the use of technology to control and monitor processes, reducing human intervention and improving efficiency. In this text, we will discuss the importance of automation in engineering and provide a translation in English.1. Importance of Automation in Engineering:Automation has revolutionized the engineering sector by streamlining processes, enhancing productivity, and reducing errors. Some key benefits include:1.1 Increased Efficiency:Automation eliminates the need for manual intervention in repetitive and time-consuming tasks. This allows engineers to focus on more complex and critical aspects of their work, leading to increased efficiency and productivity.1.2 Improved Accuracy:Automated systems are designed to perform tasks with precision and accuracy, reducing the margin of error. This is particularly important in engineering, where even a small mistake can have significant consequences.1.3 Enhanced Safety:Automation in engineering has significantly improved safety standards by minimizing the risk of accidents. Robots and machines can handle dangerous tasks that may pose a threat to human workers, ensuring a safer work environment.1.4 Cost and Time Savings:By automating processes, engineering companies can reduce labor costs and save time. Automated systems can work continuously without breaks, leading to faster project completion and reduced operational expenses.2. Examples of Automation in Engineering:Automation is widely used in various branches of engineering. Here are a few examples:2.1 Manufacturing Automation:In the field of manufacturing, automation is extensively utilized to streamline production lines. Robots and computer-controlled machines are employed to carry out tasks such as assembly, welding, and quality control. This not only improves efficiency but also ensures consistent product quality.2.2 Process Automation:Process automation involves the use of control systems to monitor and regulate industrial processes. In engineering, this can include tasks such as temperature control, pressure regulation, and flow management. By automating these processes, engineers can optimize efficiency and ensure consistent output.2.3 Building Automation:Building automation systems are used to control and monitor various aspects of a building, such as lighting, HVAC (heating, ventilation, and air conditioning), and security. These systems improve energy efficiency, comfort, and security while reducing operational costs.2.4 Transportation Automation:Automation has greatly impacted the transportation sector, particularly in engineering fields such as automotive and aerospace. Automated assembly lines and robotic systems are used in vehicle manufacturing, while autopilot systems and advanced navigation technologies have revolutionized the aviation industry.3. Translation:自动化在工程领域的重要性引言：自动化在各个行业中都扮演着重要角色，其中包括工程领域。
自动化专业英语第三版1.1 介绍过程控制1.近年来，对过程系统的性能改善需求变得越来越困难. 更为激烈的竞争，更加严格的环境和安全规范，以及快速变化的经济条件都是加强工厂产品质量规范的关键因素2.更为复杂的情况是，由于现代制造业朝着规模更大,集成度更高的方向发展,而使不同的加工环节之间的协调能力更低, 所以加工过程更难控制.在这种工厂中，要想让一个生产环节出现的问题不对其相连的另一个生产环节产生影响,几乎是不可能的.3.近年来，考虑到工业制造逐渐加强的安全、高效需求，过程控制这个课题变得越来越受重视.实际上，对于大多数现代工业，要满足安全、高效，产品质量的要求，没有控制系统是不可能的.1.1.1说明性的例子1.图1.1.1 所示的连续加热搅拌器可以作为过程控制的典型例子.输入液态流体的质量流量率为w，温度为Ti. 槽内成分搅拌均匀，并且用电加热器，功率为Q瓦特.2.假设输入和输出流量率是相等的，并且液体密度保持恒定，也就是说温度变化足够小，密度对温度的影响可以忽略不计. 在这些条件下，槽内液体的体积保持恒定3.加热搅拌器的控制目标是保持输出温度T在一个恒定参考值TR上.参考值在控制术语中指的是给定值. 下面我们考虑两个问题.把加热搅拌器内的液体从输入温度Ti加热到输出温度TR，需要多少热量？1.要确定达到设计运行条件下的热量需求，我们需要写下槽内液体的稳定能量平衡式.在写平衡式之前，假设槽内是完美搅拌的，同时忽略热损耗.2.在这些条件下，槽内成分的温度保持一致，因此，输出温度等于槽内液体温度..3.分别表示Ti, T, w, 和 QC 是液体的比热. 我们假设C是恒定的. 在设计条件下，将其代入方程（1），1.方程（2）是加热器的设计方程.如果我们的假设是正确的，同时输入流量和输入温度等于他们的标定值，那么有方程（2）给出的输入热量将使输出温度保持在期望值TR.但是，如果给定条件变化，会产生什么样的结果呢？这给我们带来第二个问题：2.问题2. 假设输入温度Ti随时间变化. 我们如何确保温度T保持或靠近给定值TR？最为一个特殊的例子，假设Ti增加到一个大于的值. 如果Q保持在标定值上恒定，我们可以得到输出温度将增加，因此T>TR.为应付这种情况，有一些可能的策略控制出口温度T方法1。
Lesson 1.1 Introduction to Process Control•In recent years the performance requirements for process plant have become increasingly difficult to satisfy. 近年来，对过程系统的性能改善需求变得越来越困难. •Stronger competition, tougher (更加严苛的) environmental and safety regulations (法规), and rapidly changing economic conditions have been key factors in the tightening of plant product quality specifications (产品质量规范).更为激烈的竞争，更加严格的环境和安全规范，以及快速变化的经济条件都是制约工厂产品质量规范的关键因素。
• A further complication (复杂) is that modern processes have become more difficult to operate because of the trend toward larger, more highly integrated plants with smaller surge capacities (谐振能力) between the various processing units. 更为复杂的情况是，由于现代制造业朝着规模更大,集成度更高的方向发展,而使不同的加工环节之间的协调能力更低, 所以加工过程更难控制.•Such plants give the operators little opportunity to prevent upsets (扰乱) from propagating from one unit to other interconnected units. 在这种工厂中，要想让一个生产环节出现的问题不对其相连的另一个生产环节产生影响,几乎是不可能的.•In view of (考虑到，由于) the increased emphasis placed on safe, efficient plant operation, it is only natural that the subject of process control has become increasingly important in recent years. 近年来，考虑到工业制造逐渐加强的安全、高效需求，过程控制这个课题变得越来越受重视.•In fact, without process control it would not be possible to operate most modern processes safely and profitably (有利的), while satisfying plant quality standards.实际上，对于大多数现代工业，要满足安全、高效，产品质量的要求，没有控制系统是不可能的•As an introduction to process control, consider the continuous (连续) stirred-tank heater (加热搅拌器)•The inlet liquid stream has a mass flow rate w and a temperature T i. The tank contents are well agitated (搅动) and heated by an electrical heater that provides Q watts (瓦特).输入液态流体的质量流量率为w，温度为Ti. 槽内成分搅拌均匀，并且用电热器加热，功率为Q瓦特。
•It is assumed that the inlet and outlet flow rates are identical (相同的) and that the liquid density ρ (rho) remains constant, 假设输入和输出流量率是相等的，并且液体密度保持恒定•that is, the temperature variations are small enough that the temperature dependence of ρ can be neglected. 也就是说温度变化足够小，密度对温度的影响可以忽略不计•Under these conditions the volume V of liquid in the tank remains constant. 在这些条件下，槽内液体的体积保持恒定•The control objective for the stirred-tank heater is to keep the exit temperature T at a constant reference value T R. 加热搅拌器的控制目标是保持输出温度T在一个恒定参考值T R上•The reference value (参考值，给定值) is referred to as a set point (设定值，给定值) in control terminology (术语). Next we consider two questions.在控制术语中，参考值指的是给定值. 下面我们考虑两个问题•Question 1: How much heat must be supplied to the stirred-tank-heater to heat the liquid from an inlet temperature T i to an exit temperature T R?把加热搅拌器内的液体从输入温度T i加热到输出温度T R，需要多少热量？•To determine the required heat input for the design operating conditions, we need to write a steady-state (稳态) energy balance (能量平衡) for the liquid in the tank. 要确定达到设计运行条件下的热量需求，我们需要写下槽内液体的稳态能量平衡式•In writing this balance, it is assumed that the tank is perfectly mixed and that heat losses are negligible. 在写平衡式之前，假设槽内是完美搅拌的，同时忽略热损耗•Under these conditions there are no temperature gradients (梯度) within the tank contents and consequently, the exit temperature is equal to the temperature of the liquid in the tank. 在这些条件下，槽内成分的温度保持一致，因此，输出温度等于槽内液体温度• A steady-state energy balance for the tank indicates that the heat added is equal to the change in enthalpy (焓, 表示物质内能，可以理解为衡量物质温度的物理量) between the inlet and exit stream. 根据稳态能量守恒，加入的热量等于输入和输出流体之间的焓变化量•....Thus, if T is too high we would decrease w to reduce the energy input rate in the stirred tank relative to the mass flow rate and thereby reduce the exit temperature.因此，如果温度太高，我们将降低流量率w，使得搅拌槽内的与质量流量率相关的能量输入速率减少，因此使输出温度得以降低•…Place a heat exchanger on the inlet stream.•The heat exchanger is intended to reduce the disturbances in Ti and consequently reduce the variation in T. This approach is sometimes ca lled “hog-tieing” (把脚或腿束缚住，这里意思与restraint 相近，解释为约束、束缚) an input.方法7. 在输入流安置一个热交换器. 热交换器意图减少Ti的干扰，因此可以减少温度T的扰动. 这个方法有时又叫做输入束缚法.•Method 8. Use a larger tank.•If a larger tank is used, fluctuations (波动) in Ti will tend to be damped out (阻尼，衰减) due to the larger thermal capacitance of the tank contents. However, increased volume of tankage would be an expensive solution for an industrial plant due to the increased capital costs of the larger tank.方法8. 使用一个更大的槽. 如果使用更大的槽，因为更大的热容，Ti的波动会趋向于衰减. 然而，体积增加使得开支增加，会使工厂系统的解决方案变得更加昂贵.•Note that this approach is analogous to the use of water baths in chemistry laboratories where the large thermal capacitance of the bath serves as a heat sink (散热装置) and thus provides an isothermal (恒温的) environment for a small-scale research apparatus (仪器). 要指出的是这个方法类似于化学实验室中水缸的使用，水缸大的热容量可以看作散热装置，因此可以为小型实验仪器提供一个恒温环境.•Next, we will classify the eight control strategies of the previous section and discuss their relative advantages and disadvantages. 接下来，我们将给这8种控制方法进行分类，同时讨论他们各自的优缺点•Methods 1 and 3 are examples of feedback control (反馈控制) strategies. In feedback control, the process variable to be controlled is measured and the measurement is used to adjust another process variable which can be manipulated (操作，操纵). 方法1和3 是反馈控制的例子. 在反馈控制中，测量被控过程变量，该测量值用于调整另一个可以操做的过程变量.（即测量变量，操作变量，测量变量用于调整操作变量.）•...It is important to make a distinction between negative feedback (负反馈)and positive feedback (正反馈). Negative feedback refers to the desirable situation where the corrective action taken by the controller tends to move the controlled variable toward the set point. 区分负反馈和正反馈很重要. 负反馈是指期望达到的形势，控制器的校正作用使得被控变量趋于给定值.•In contrast, when positive feedback exists, the controller tends to make things worse by forcing the controlled variable farther away from the set point. 相反地，当正反馈存在时，控制器使局面变得更加糟糕，它使被控变量远离给定值•Thus, for the stirred-tank heater, if T is too high we would decrease Q (negative feedback) rather than increase Q (positive feedback).因此，对于加热搅拌器来说，如果T太高，我们将减少输入Q（负反馈），而不是增加输入热量Q（正反馈）•...So far (到目前为止) we have considered only one source of process disturbance, fluctuations in T i. We should also consider the possibility of disturbances in other process variables such as the ambient (周围的) temperature, which would affect heat losses from the tank. 到目前为止，我们仅仅考虑了Ti波动这一种干扰源. 我们也应该考虑其他过程变量干扰的可能性,如会影响槽中散热量的环境温度•Recall that heat losses were assumed to be negligible earlier. 回忆一下前面我们假定热损失是可忽略的•Changes in process equipment are another possible source of disturbances. For example, the heater characteristics (特性) could change with time due to scaling (结垢) by the liquid. 过程设备的变化是另一个可能的干扰源. 例如，加热器的特性会因为液体结垢而随时间变化•It is informative to examine the effects of these various types of disturbances on the feedforward and feedback control strategies discussed above.考察这些不同类型的干扰对前馈和反馈控制策略的影响是有益的•First, consider the feedforward control strategy of Method 2 where the disturbances in Ti are measured and the measurements are used to adjust the manipulated variable Q. 首先，考虑方法2中的前馈控制方法,在这种方法中测量的是干扰Ti，并且测量用于调整可操作量Q•From a theoretical point of view, this control scheme (方案) is capable of keeping the controlled variable T exactly at set point T R despite disturbances in T i. 从理论上讲，尽管存在干扰Ti, 这种控制方案有能力保持被控变量精确在给定值T R•Ideally, if accurate measurements of T i were available and if the adjustments in Q were made in an appropriate manner, then the corrective action taken by the heater would cancel out the effects of the disturbances before T is affected.在理想情况下,如果对Ti 的精确的测量是可得的,并且以一种合适的方法对Q进行调整，那么加热器的校正作用将在T被作用以前就抵消干扰的影响.•Thus, in principle, feedforward control is capable of providing perfect control in the sense that the controlled variable would be maintained at the set point.如此而言,从维持被控变量在给定值的意义上讲,前馈控制原则上能够提供完美(无差，没有误差)的控制.•But how will this feedforward control strategy perform if disturbances occur in other process variables? 但是如果干扰源来自其他过程变量,这种前馈控制的策略如何发挥作用呢？•In particular, suppose that the flow rate w cannot be held constant but, instead, varies over time. In this situation, w would be considered a disturbance variable. 特别地,假如流量w不能维持恒定，而是随时间变化. 在这种情况下，w被看作是一个扰动变量•If w increases, then the exit temperature T will decrease unless the heater supplies more heat.如果w增加,出口温度T将减少,除非加热器提供更多的热量•However, in the control strategy of Method 2 the heat input Q is maintained constants as long as Ti is constant. 然而,在方法2的控制策略中,只要Ti不变,热量输入值Q就维持恒定•Thus no corrective action would be taken for unmeasured flow disturbance. 因此,对没有测量的流量扰动就不会采取校正动作•In principle, we could deal with this situation by measuring both Ti and w and then adjusting Q to compensate for both of these disturbances.原则上说,处理这种情况,我们可以同时测量Ti和w,然后调整Q来同时补偿这两种扰动•However, as a practical matter it is generally uneconomical to attempt to measure all potential disturbances. 然而,从实际出发,试图测量所有潜在的干扰一般来说是昂贵的•It would be more practical to use a combined feedforward-feedback control system, since feedback control provides corrective action for unmeasured disturbances, as discussed below. 既然反馈控制可以对未知的干扰提供校正动作,采用前馈和反馈组合的控制策略将更加实际,正如我们下面将要讨论的那样•Consequently, in industrial applications feedforward control is normally used in combination with feedback control. 因此在工业应用中,前馈控制一般是和反馈控制结合使用的•Next, we will consider how the feedback control strategy of Method 1 would perform in the presence of disturbances in Ti or w. 下面我们考虑扰动Ti或w出现的情况下，方法1的反馈控制如何实行•If Method 1 were used, no corrective action would occur until after the disturbance had upset the process, that is, until after T differed from T R. 如果采用方法1, 校正动作只有在干扰已经影响了过程之后发生，也就是说, 直到T偏离了T R之后•Thus, by its inherent (内在的) nature, feedback control is not capable of perfect control since the controlled variable must deviate (偏离) from the set point before corrective action is taken. 由于在校正动作产生前,被控量必须偏离给定值,所以就其本身的固有属性而言,反馈控制不是完美(无差)控制•However, an extremely important advantage of feedback control is that corrective action taken regardless of the source of the disturbance. 然而,反馈控制的一个极其重要的优点是, 不论对什么样的扰动, 都可以产生正确的校正动作•Thus, in Method 1, corrective action would be taken (by adjusting Q) after a disturbance in Ti or w caused T to deviate from the set point.因此，在方法1中, 当扰动Ti 或w 引起T偏离给定值后，校正动作都会产生(通过调整Q).•The ability to handle unmeasured disturbances of unknown origin is a major reason why feedback controllers have been so widely used for process control.这种处理未知起因、没有测量扰动的能力是反馈控制在过程控制中应用广范的主要原因•••••••••••••••••••••••••••••••••••••••••。
