1、1PART 1 电路和电子工程基础 A 电路1 In the case of a resistor, the voltage-current relationship is given by Ohms law, which states that the voltage across the resistor is equal to the current through the resistor multiplied by the value of the resistance.就电阻来说，电压电流的关系由欧姆定律决定。欧姆定律指出：电阻两端的电压等于电阻上流过的电流乘以电阻值。2It ma
2、y be that the inductor voltage rather than the current is the variable of interest in the circuit.或许在电路中，人们感兴趣的变量是电感电压而不是电感电流。B 三相电路1 Viewed in this light, it will be found that the analysis of three-phase circuits is little more difficult than that of single-phase circuits. 这样看来，三相电路的分析比单相电路的分析难不了多
3、少。2 At unity power factor，the power in a single-phase circuit is zero twice each cycle在功率因数为 1 时，单相电路里的功率值每个周波有两次为零。3 It should be noted that if the polarity of point A with respect to N ( ) is assumed for the positive half-cycle, then when used in the same phasor diagram should be drawn opposite to
4、, or 180 out of phase with, .应该注意，如果把 A 点相对于 N 的极性（ ）定为正半周，那么 在用于同一相量图中时就应该画得同 相反，即相位差为 180。A 运算放大器1 One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system.对应于像广义放大器这样的电子装置，一个问题就是增益 AU 或者AI ，
5、它们取决于两输入端系统的内部特性。2 This is one of the key features of Op-Amp designthe action of the circuit on signals depends only upon the external elements which can be easily varied by the designer and which do not depend upon the detailed character of the Op-Amp itself.这是运算放大器设计的重要特征之一在信号作用下，电路的动作仅取决于能够容易被设计者
6、改变的外部元件，而不取决于运算放大器本身的细节特性。B 晶体管1 Put very simply a semiconductor material is one which can be “doped” to produce a predominance of electrons or mobile negative charges (N-type); or “holes” or positive charges (P-type).简单地说，半导体是这样一种物质，它能够通过“掺杂”来产生多余的电子，又称自由电子（N 型） ；或者产生“空穴” ，又称正电子（P 型） 。2 TO1 is the
7、original transistor shapea cylindrical “can” with the three leads emerging in triangular pattern from the bottom. Looking at the base, the upper lead in the “triangle” is the base, the one to the right (marked by a color spot) the collector and the one to the left the emitter.TO1 是最早的一种晶体管形状即一个带有三个引
8、脚的圆柱体“外罩” ，这三个引脚在底部形成三角状。首先要注意的是， “三角形”上面的引脚是基极，其右面的引脚（由一个彩色点标出）为集电极，其左面的引脚为发射极。 A 逻辑变量与触发器1 We shall now briefly discuss the relevance of such terminology, and in so doing we shall bring out the special aptness of the designations “true” and “false” to identify the possible values of a variable. 现在
9、我们将简要地讨论一下这些术语之间的关联，并在此过程中阐明用标示“真”和“假”来识别一个变量的可能值的特殊用途。2 Just as other algebras deal with variables which have a numerical significance, Boolean algebra deals with propositions and is an effective tool for analyzing the relationships between propositions which allow only two mutually exclusive alter
10、natives.和其他处理有数字意义的变量的代数一样，布尔代数处理的是命题，而且布尔代数对于分析仅有两个互反变量命题之间的关系是一种有效的工具。3 There is a generally prevailing attitude in digital systems to view logic 0 as a basic, undisturbed, unperturbed, quiescent state and to view the logic 1 state as the excited, active, effective state, i.e., the state arrived a
11、t “after something has happened.”在数字系统中，普遍的观点是把逻辑 0 看成一个基本的、无干扰的、稳定的、静止的状态，把逻辑 1 看成一个激励的、活跃的、有效的状态，也就是说，这种状态是发生在“某种操作动作之后” 。B 二进制数字系统1 Such devices operate well in a two-state or binary system, using conduction and cutoff as the operating states, and as a 2result the binary number system is generall
12、y employed in internal operations in digital computers.将导通和关断作为工作状态，这样的装置可以在两态即二进制系统中运行，因此数字计算机中的内部操作一般采用二进制系统。2 Given the basic idea of a chain of positive and negative, or positive and zero, or zero and negative pulses as representing binary 1s and 0s, there are many possible codes in which the pu
13、lses might be transmitted.给出一串正脉冲和负脉冲，或正脉冲和零，或者零和负脉冲来表示二进制的 1 及 0 时，就会有许多这些脉冲可以传递的码。A 功率半导体器件1 Power diodes provide uncontrolled rectification of power and are used in applications such as electroplating, anodizing, battery charging, welding, power supplies (DCand AC), and variable-frequency drives.
14、电力二极管提供不可控的整流电源，这些电源有很广的应用，如：电镀、电极氧化、电池充电、焊接、交直流电源和变频驱动。 2 A gate turn-off thyristor (GTO), as the name indicates, is basically a thyristor-type device that can be turned on by a small positive gate current pulse, but in addition，has the capability of being turned off by a negative gate current puls
15、e门极可关断晶闸管，顾名思义，是一种晶闸管类型的器件。同其他晶闸管一样，它可以由一个小的正门极电流脉冲触发，但除此之外，它还能被负门极电流脉冲关断。3 Such a gate current pulse of very short duration and very large di/dt has small energy content and can be supplied by multiple MOSFETs in parallel with ultra-low leakage inductance in the drive circuit.这样一个持续时间非常短、di/dt 非常大、
16、能量又较小的门极电流脉冲可以由多个并联的 MOSFET 来提供，并且驱动电路中的漏感要特别低。 B 电力电子变换器1 The efficiency of the rectifiers is very high, typically in the vicinity of 98%, because device conduction loss is low and switching loss is practically negligible.由于器件开通时损耗低，且其开关损耗几乎可忽略不计，故该类整流器的效率很高，典型值约为 98。2 A variable voltage source can
17、 be converted to a variable current source by connection a large inductance in series and controlling the voltage within a feedback current control loop.通过串联大电感，可变电压源可以在电流反馈控制回路的控制下转换为可变电流源。A 直流电机分类1 Each of these motors has different characteristics due to its basic circuit arrangement and physical
18、 properties.每种类型的电动机由于其基本电路的不同而具有不同的特征和物理特性。2 The only difference, in most cases, is that the generator acts as a voltage source while the motor functions as a mechanical power conversion device.很多情况下，二者的唯一区别在于发电机常作为电压源，而电动机常作为机械能转换装置。3 A decrease in field current reduces the strength of the electro
19、magnetic field. When the field flux is decreased, the armature will rotate faster, due to reduced magnetic-field interaction.励磁电流的减小会使磁场减弱。当磁通减少时，转子会由于与减弱的磁场相互作用而加速旋转。B 直流传动的闭环控制1 Any positive speed error, caused by either an increase in the speed command or an increase in the load torque, produces
20、a higher current reference Ia*.由速度给定或负载转矩的增加所引起的任何正的速度偏差，都会产生更大的参考电流值 Ia*。2 The speed error is corrected at the maximum permissible armature current until the speed error becomes small and the current limiter comes out of saturation.在最大允许电枢 I 下纠正速度偏差，直到速度偏差减小且限流装置退出饱和状态。A 交流机1 Neglecting the effect
21、of slots and space harmonics due to non-ideal winding distribution, it can be shown that a sinusoidal three-phase balanced power supply in the three-phase stator winding creates a synchronously rotating magnetic field.如果忽略槽和由于非理想分布的绕组产生的空间谐波的影响，可以证明，在三相定子绕组中能以三相对称电源建立一个同步旋转的旋转磁场。2 The rotor winding
22、will be subjected to a sweeping magnetic field, and have inducing current in the short-circuited rotor.转子绕组切割磁场，就会在短路的转子中产生感应电流。 3 This is in contrast to a machine with a cylindrical rotor structure having a uniform air gap (such as an induction motor), 3defined as a nonsalient pole machine.与其(凸极式同步
23、机) 对应的另一种电机是有均匀气隙的圆柱体形转子结构的电机(与异步机相似)，定义为隐极式同步电机。4 For example, the stator-pole pair A-A is energized when the rotor pole-pair a-a approaches it to produce the torque by magnetic pull, but is de-energized when pole alignment occurs.例如，当转子极对 a-a接近定子极对 A-A时，定子极对 A-A被通电，通过磁拉力产生转矩，当两个极对重合时，定子极对 A-A断电。 B
24、 感应电机传动装置1 However, as the frequency is increased, the machine airgap flux falls causing low developed torque capability.然而随着频率增加，电机的气隙磁通下降，导致产生的转矩降低。2 In a well-designed PWM drive, the commutation frequency should be increased as permitted by the devices so as to obtain a good balance between the i
25、ncrease of inverter loss and decrease of machine loss.在设计完善的 PWM 传动系统中，应在器件允许的条件下增加换相频率，以便在逆变器损耗的增加和电机损耗的降低之间找到一个合适的平衡点。A 电力系统 1 In cities and other areas where open lines create a safety hazard or are considered unattractive, insulated underground cables are used for distribution.在城市和其它地区，明线存在安全隐患或
26、者被认为影响美观，所以使用绝缘地下电缆进行配电。2 Each utility that agrees to share gains an increased reserve capacity, use of larger, more efficient generators, and the ability to respond to local power failures by obtaining energy from a linking grid.同意共享的每个电力企业可以获得不断增加的储备功率，使用更大、效率更高的发电机，从电网中获取电能以应对局部电力故障。3 Inductance
27、and capacitance react with a tendency to nullify one another.电感和电容的作用能相互抵消。B 电力系统自动化 1 Metering values such as demand and peak are saved within the meter to create historical information about the activity of the power system.测量值，如需求量和峰值，可以保存在仪表中，用于创建电力系统运行的历史信息。2 Substation integration refers to co
28、mbining data from the IEDs local to a substation so that there is a single point of contact in the substation for all of the I that is, the engineer needs to look at the complete plant rather than only one piece of equipment.这并不一定是最安全的全局操作，也就是说，工程师应从整个工厂着眼，而不是仅注意某一台设备。A P 控制器和 PI 控制器1 Proportional o
29、nly controllers have the advantage of only one tuning parameter, Kc.纯比例控制器的优点是只需整定一个参数 Kc。2 Also, from Eq.(5-3A-6) we note that as long as the error term is present, the controller will keep changing its output, thereby integrating the error, to remove the error.从式(5-3A-6)中，我们注意到只要误差项存在，控制器就会不断改变其输出
30、，从而通过对误差积分来消除误差。B PID 控制器和其它控制器1 PID controllers are recommended for long time constant loops which are free of noise.PID 控制器适用于不易受噪声干扰的具有长时间常数的环路系统。2 A few other comments on controllers are in order before closing this section.在结束这节之前，有必要再对控制器作一些说明。3 The slope of the ramp is predetermined by the op
31、erating personnel.斜坡函数的斜率要由操作人员预先设定。A 指示性仪表1 In addition to precision digital-type indicators, alarms and annunicators also operate on a pseudodigital principle, in that they only indicate certain Go/No-Go types of situations as in the use of colored lights or horns and bells to indicate limits that
32、 have been exceeded. 除了精确数字式仪表外，报警器和指示器同样根据近似于数字式的原理工作，因为它们仅指示某些运行或停止的状态，比如使用彩色指示灯、喇叭和电铃来指示某些超出界限的情况。2 Indicating instruments also can be classified in terms of speed which, unless associated with a rapid-recording means, must fall within the capabilities of human identification and resolution. 指示性仪
33、表也可以根据速度来分类，除了一些同快速记录有关的仪表以外，所有的仪表，其速度都必须在人的辨别力和分辨力以内。3 , thus will not overengineer or underdesign the mode of indication.，因而显示的模式既不会过分复杂，也不8会设计欠周。B 控制盘1 The control panel, whether a single panel of simplified design for local mounting or part of an extensive control center, literally is the interf
34、ace between the operator and the process.不论是作为局部安装简化设计的单块屏，还是作为大范围控制中心的一部分，控制盘实际上就是操作人员与控制过程之间的界面。2 All the foregoing objectives and more are subject, of course, to trade-offs wherein cost must be weighed against projected gains. 所有前面提到的目标和其他问题当然要经过比较，其中，投资花费和预期收益必须经过权衡。PART 5 基于网络和信息的控制 A 自动化网络的应用领
35、域1 For example, factory automation and process automation are often used in harsh and hazardous environments where people, nature, and expensive machinery are at stake or where a production interruption is costly. These requirements contrast significantly with building automation, for example, where
36、 keeping costs low is a main driving force.举例而言，工厂自动化与过程自动化通常应用在苛刻和危险的场合。而在这些场合，人员、环境及昂贵的机器设备处于危险之中，或者生产的中断会造成巨大损失。这些需求同追逐低成本的楼宇自动化相比，有明显的差异。2 The network types ideal for simple discrete I/O focus on low overhead and small data packets, but they are unsuitable for larger messages like configuration
37、download and the like. 对简单的离散 I/O 较为理想的网络类型注重低开销及小的数据包，但它们不适用于组态下载等较大的报文。B 控制系统体系结构的演变 1 In the pneumatic era the controller was typically situated in the field and there operated locally.There was therefore no system to speak of. 在气动时代，控制器一般位于现场并就地进行操作，因此毫无系统可言。2 When introduced, the DCS was christ
38、ened “distributed” because it was less centralized than the DDC architecture. By todays standards, however, the DCS is considered centralized. DCS 之所以一开始被冠名为“分散”的，是因为它没有 DDC 体系结构那么集中。但是， 如按今天的标准来衡量， DCS 应该被认为是集中的。3 One of the possibilities that a standard programming language and powerful communicat
39、ions features enable is the ability to perform control that is distributed into the field devices rather than a central controller.标准的编程语言同强有力的通信功能相结合的结果之一是将控制分散到现场设备中，而不集中在一个控制器上。A 网络控制系统中的基本问题1 Ethernet employs a CSMA with collision detection (CSMA/CD) protocol. When there is a collision, all of t
40、he affected nodes will back off, wait a random time (usually decided by the binary exponential backoff algorithm), and retransmit, as shown in Case 3 of Fig.5-1A-2.以太网采用 CSMA/CD 协议，当产生冲突时，所有冲突节点都将避让等待一段时间（所等待的时长是由二进制指数避让算法决定的） ，然后重新发送，如图 5-2A-2 中所示的第三种情况。B 带网络延时的网络控制系统的稳定性1 we can use the stability
41、triangle to explicitly calculate the relation between and .我们可以采用稳定三角形精确地计算出 和 之间的关系。2 It may be analytically infeasible to derive the exact stability region for general systems; however, stability regions for such systems can still be determined by simulation.A 自动化网络的应用领域1 For example, factory auto
42、mation and process automation are often used in harsh and hazardous environments where people, nature, and expensive machinery are at stake or where a production interruption is costly. These requirements contrast significantly with building automation, for example, where keeping costs low is a main
43、 driving force.举例而言，工厂自动化与过程自动化通常应用在苛刻和危险的场合。而在这些场合，人员、环境及昂贵的机器设备处于危险之中，或者生产的中断会造成巨大损失。这些需求同追逐低成本的楼宇自动化相比，有明显的差异。2 The network types ideal for simple discrete I/O focus on low overhead and small data packets, but they are unsuitable for larger messages like configuration download and the like. 对简单的离
44、散 I/O 较为理想的网络类型注重低开销及小的数据包，但它们不适用于组态下载等较大的报文。B 控制系统体系结构的演变1 In the pneumatic era the controller was typically situated in the field and there operated locally.There was therefore 9no system to speak of. 在气动时代，控制器一般位于现场并就地进行操作，因此毫无系统可言。2 When introduced, the DCS was christened “distributed” because i
45、t was less centralized than the DDC architecture. By todays standards, however, the DCS is considered centralized. DCS 之所以一开始被冠名为“分散”的，是因为它没有 DDC 体系结构那么集中。但是， 如按今天的标准来衡量， DCS 应该被认为是集中的。3 One of the possibilities that a standard programming language and powerful communications features enable is the
46、ability to perform control that is distributed into the field devices rather than a central controller.标准的编程语言同强有力的通信功能相结合的结果之一是将控制分散到现场设备中，而不集中在一个控制器上。A 网络控制系统中的基本问题1 Ethernet employs a CSMA with collision detection (CSMA/CD) protocol. When there is a collision, all of the affected nodes will back
47、off, wait a random time (usually decided by the binary exponential backoff algorithm), and retransmit, as shown in Case 3 of Fig.5-1A-2.以太网采用 CSMA/CD 协议，当产生冲突时，所有冲突节点都将避让等待一段时间（所等待的时长是由二进制指数避让算法决定的） ，然后重新发送，如图 5-2A-2 中所示的第三种情况。B 带网络延时的网络控制系统的稳定性1 we can use the stability triangle to explicitly calcu
48、late the relation between and .我们可以采用稳定三角形精确地计算出 和 之间的关系。2 It may be analytically infeasible to derive the exact stability region for general systems; however, stability regions for such systems can still be determined by simulation.对于一般的系统不太可能推导出精确的稳定区域，然而却可以通过仿真的方法来确定。A 计算机集成制造的概念1 The Computer an
49、d Automation System Association (CASA) of the Society of Manufacturing Engineers (SME) defined CIM as follows: CIM is the integration of the total manufacturing enterprise through the use of integrated systems and data communications coupled with new managerial philosophies that improve organizational and personnel efficiency.制造业工程师协会下的计算机与自动化协会对计算机集成制造定义如下：计算机集成制造就是通过利用集成的计算机与数据通信系统并融合管理哲学，将整个生产制造企业集成为一体，从而提高组织运作效率及员工的工作效率。2 The se
