本科毕业生外文文献翻译.doc

本科毕业生外文文献翻译 学生姓名：李玄彤指导教师：赵肖宇所在学院：信息技术学院专 业：通信工程中国大庆2011 年 5 月原文Industrial Ethernet and Intelligent Building1 Industrial Ethernet the background1.1 Unified field bus standards dashed, the temptation remains In 1984 the United States proceed to develop international standards field bus, a few years, the major companies for commercial interests, Field bus standards can not always uniform. Through multiple voting, consultation, in January 2000 announced that the field bus international standards IEC61158 will be eight bus (Prefabs, Interfuse, P-NET, World, etc.) at the same time as international standards (currently has 10 kinds), formed The outcome of a compromise. At the same time, major foreign companies have also launched its own standards, such as LONWORKS, CAN, Japans Mitsubishi, France Schneider, the current number of bus standards at the same time the situation still exists, they say the openness and interoperability only At the same can be achieved under a bus standard, different standards between the bus is still limited. The interconnection between different bus and can not be guaranteed, so people in their efforts to seek a unified standard field bus, some people have proposed the use of TCP / IP protocol Ethernet. 1.2 The demand for system integration （1） industrial automation control integrated enterprise information is Chinas national policy to create automation and information technology as an example: In the need to change the business processes of the same time, management information systems and e-commerce, decentralized network of manufacturers to be integrated, the existing enterprise resource ERP transformed into WEB-based applications. The current single from the automation of industrial automation, factory automation, to the development of automation systems, the underlying message should be integrated into the upper information online in order to achieve the integration of control as shown in an integrated system.Modern production system for a multi-storey industrial control systems, generally fall into three tiers: Equipment-testing equipment and connectivity implementing agencies; Control of the data obtained from the scene equipment, complete the various control, monitoring operating parameters, alarm and historical trend analysis; Information layer will control the data processing system after spread to the higher level management network (TCP / IP Ethernet), in order to achieve integrated management of its network structure 。（2） Intelligent Building of the urban information system integration, the development of digital, intelligent building (including intelligent residential district), has become a digital citys information site, in order to achieve information sharing, the need to achieve control network and information network of vertical integration, that is, Control network and TCP / IP Ethernet integration. As various subsystems and communications equipment at the scene agreement is diversified and integrated these two models must be developed gateways, in order to achieve the conversion agreement and unity, this has increased the complexity of system integration technology and increase costs. It was boldly put forward can use TCP / IP protocol as a unified agreement, the scene of the subsystems and equipment directly from Ethernet to simplify the system integration of technical difficulty, lower costs, so that control signals directly from the Ethernet transmission, So the concept of industrial Ethernet has been raised. 2 Ethernet and CSMA / CD2.1 Ethernet Ethernet (Ethernet) 1975 by the United States XEROX company successfully developed, as a passive medium (such as twisted pair, coaxial cable, etc.) to disseminate information, to the history of the spread of electromagnetic waves known as the Ethernet (Ether ) To name. 1980 by the DEC, INTEL, XEROX jointly launched a three EthernetV2, is the worlds first LAN standard. 1983 IEEEE802 Committee DIX EthernetV2 based introduced IEEE803, using the CSMA / CD MAC technology. 802.3 refer to a CSMA / CD networks, and Ethernet DIX EthernetV2 from the standard definition, not strictly in the circumstances, can be called 802.3 LAN, which is Ethernet. To the modern manufacturing industry as an example, its modern manufacturing automation model in Figure .Industrial Ethernet is the commercial application of Ethernet to industrial control systems, the two networks is not essentially different from, the two are compatible. 2.2CSMA / CD (Carrier Sense Multiple Access with Collision DetectionMulti-carrier monitoring visit / conflict detection) CSMA / CD are the first improvement comes from CSMA. （1） CSMA (Carrier monitor multiple access): stop trying to send a signal, first of all to monitor bus, to determine whether there is other media, to stop the signal. If the media is free, you can send; If the media are in working condition, then wait some try again after the interval, when heard in a busy state media, CSMA There are several different ways to deal with, the availability of interception of signal: adhere to non-CSMA, 1 - adhere to CSMA, P - Consistently CSMA. （2） CSMA / CD to hear not only the first, but also Baiting Bain hair, a bus in the conflict, but once the conflict was detected; they stopped sending the frame, to give up their own frame. In order to know that other stations can also have a conflict, listening to the conflict to the bus station on the spread of a blocking signal interference, informed the bus station in the conflict have taken place, the capacity of this channel will not be sent because the frame was damaged and waste. With the increased network load, the collision would increase the opportunities, network efficiency decreased significantly. 3 Industrial Ethernet the existing problemsField Bus is used for industrial control and complex and harsh environment of industrial design at the scene, the system of real-time and response time have strict demands on electricity use of the environment, there are special requirements. Since Ethernet is designed for information and communications, industrial control for the existence of the following questions: (1) using Ethernet CSMA / CD Access Protocol, which is a non-deterministic network.The high demand for real-time control systems, this uncertainty will result in the requested information can not convey. The so-called network segment is even shared the same bus network, you can listen to the message sent by the other side, at the same collision regional conflict (a conflict that will impact the region) of workstations and servers to connect the network area. For example, in a collision conflict in the region have a working group (from a server and workstation components multiple), when more than one visit a server workstation, due to the CSMA / CD bound by the same time allowing only a workstation and server Communications, can only wait for the other workstations. Competition for the workstation communication channel so that the communication workstations have delayed, and this extensionWhen the time is uncertain, workstations more competition for communications for the longer this situation known as the load was more severe the longer the waiting time. If in a collision domain, assume that two working groups, in a collision domain, the first work group servers, workstations access to competitive broadband networks (such as 100 M), another working group of all workstations and servers Are in a wait state and can not run. The two working groups to split the original broadband network (100 M), a working group work, must wait for another group, this has not only delayed, and this delay is uncertain. As CSMA / CD have unforeseen delay, particularly in the heavy load, the more real-time data transmission can not be guaranteed. Therefore Ethernet control system must be solved for real-time and uncertainty. (2) Ethernet in reliability than Bus at the scene.Field Bus is designed for industrial control, able to adapt flammable, explosive (such as chemicals, pharmaceuticals), strong interference and other occasions poor environment occasions. Field bus have shielding, grounding and explosion-proof measures, such as Ethernet and the need to address these issues. (3) Field bus specifications on the network segment with a power supply.For all non-self-powered equipment to power and Ethernet does not provide power, the need for additional electricity supply lines. 4 feasibility of the application of Industrial EthernetIndustrial Ethernet for industrial control, the above-mentioned problems, with the Ethernet technology development and the implementation of corresponding measures, in fact, and the uncertainty can be made great improvements: (1) Continuously improve Ethernet rate: the rate in recent years Ethernet from 10 Mbps, 100Mbps to 1 000Mbps and has been widely applied. At present 10 Gaps Ethernet has been commercialized, greatly shortening the data transmission time, improve response time, the systems real-time and non uncertainties have improved. (2) using Ethernet switch technology: as the work site shared Ethernet channel competition arising from the conflict affected the collision of real-time system and uncertainty, Ethernet switch technology can be used to be improved. Ethernet-based exchange used in Ethernet switch, switch between the port at the same time can create a number of data channels, each connected to a network port, the port frame between the input and output no longer subject to CSMA / CD MAC bound by the agreement. When the system includes a number of working groups, in general so that each group formed a separate network segment, each of the occupation of the exchange network (of) a port (shown in Figure 4 switches are A, B, C, D 4 net), net of most of the time the work is independent, when any two of the need for information exchange network, the switch in two independent network of information between the channel .Once the end of the exchange of information, access is disconnected.This shows that switched Ethernet shared Ethernet can be overcome existing problems: Switches on each port can connect a network segment; each of the network bandwidth can be exclusive; switches on each port, the network of access between the independent and isolated, such as the need for inter-network of information and communication, it can temporarily establish an information channel, after the switch isolation, can greatly reduce the probability of conflict To improve the real-time and uncertainty; switch VLAN technology commonly used to exchange control system can be allocated to the proprietary information, access and bandwidth, thus ensuring the networks busiest time, the control system is still comfortable enough bandwidth to enable Ethernet transmission of real-time information And uncertainty remained largely theoretical level. (3) In some applications to allow the circumstances: try to control network and information networks to use separate, in order to avoid real-time data and non-real-time data of the collision, between the industrial site for independent Ethernet network segment, Thereby improving the real-time and uncertainty. In addition, full-duplex technology can be used to reduce network load, and Ethernet + TCP / IP protocol on the basis of a uniform and apply to the industrial field of application-level control measures such as technical specifications. The above measures can be taken so that in some industrial Ethernet military, industrial, civilian areas of the site has been initially applied in the measurement and control. For example, many countries abroad nuclear accelerator as the Ethernet monitoring and control options, in addition automobile assembly line, thin steel production lines and so on a programmed of industrial Ethernet, monitoring and control from the direction of development of the area, the industrial Ethernet will be Monitoring is the future in the field of an important direction of development, but also the corporate-controlled integration and intelligent building systems integration as a best option. (4) Ethernet power supply problem: over the years has been a defect, especially as IP phones, IP cameras, wireless AP, ENC (Ethernet Control System) system and other applications, more people put in Ethernet transmission Data at the same time, send some energy, small network equipment to meet the demand for electricity, power supply network equipment to solve the small state of disorder and the high cost of power supply wiring. So the IEEE 802.3af standard that is called out, has formed an Ethernet-powered international standards, 3 COM, Hawaii, DLINK, and other companies have with 802.3 aft-standard switching products. IEEE 802.3af standard is the core to meet the standards of 802.3 at the same time, by switching to the network terminal equipment to provide 48 V or 24 V power, the power supply to this industrial Ethernet issues have been very good solution, the principle shown in Figure 1.Figure 1 principle of self-powered Ethernet(5) Network of Ethernet: TCP / IP protocol is an open communication protocol. Security issues do not belong to form networks and TCP / IP protocol. Network security is the ultimate concern of the transmission network in the application layer of information security; it is not illegal changes to use. Protect the security of information transmission and either two ways: exclusive and independent access encrypted information. Before a way to let the lack should not be, the latter should not be the way to get the do not know. Ethernet virtual private network switching technology has become a basic network dedicated channel technology, already very mature and widely used. Ethernet can easily access will require isolation from. Internet information is encrypted TCP / IP on the basic nothing to do with the application of information processing methods. Prior to the issue of information is encrypted with information to carry out the use of declassified after treatment. Now basically an open encryption algorithms, do not rely on secret encryption guarantees, but by password (key). Information security key to the final and most important factor is the holder of the password; he kept using the password of course, and means the security communication system is the core. 6工业以太网与智能建筑1 工业以太网产生的背景1.1 统一现场总线标准成为泡影，诱惑依然 1984年美国着手制定现场总线国际标准，若干年以来，世界各大公司为了商业的利益，现场总线标准始终不能统一。通过多次投票、协商，2000年1月宣布的现场总线国际标准IEC61158将八种总线（Profibus，Interbus，P-NET，Worldfip等）同时列为国际标准（目前已达10种），形成一个妥协的结果。 同时，国外各大公司又推出了自己的标准，如LONWORKS、CAN、日本三菱、法国Schneider等，目前多种总线的标准同时存在的局面依然存在，人们所说的开放性和互操作性只能在同一种总线标准下实现，不同标准总线之间仍然受到限制。不同总线之间的互联性得不到保证，因此人们在努力寻求一种统一标准的现场总线，有人提出了采用TCP/IP协议的以太网。 1.2 系统集成的需求 (1)工业自动化的管控一体化 企业信息化是我国的国策，以制造自动化及信息化为例：在需要改变业务流程度的同时，将管理信息系统与电子商务、分散的网络化制造加以集成，把现有的企业资源ERP改造成为基于WEB的应用系统。目前工业自动化已从单机自动化、工厂自动化，向系统自动化发展，底层的信息要集成到上层的信息网上以实现管控一体化。现代化生产系统为一个多层的工业控制系统，一般分为三层： 设备层 联接检测设备和执行机构； 控制层 从现场设备取得数据，完成各种控制，监测运行参数，报警和历史趋势分析等； 信息层 将控制系统的各种数据加工后传至上级管理网络（TCP/IP以太网），以便实现管控一体化。 (2) 智能建筑的系统集成 城市信息化、数字化的发展、智能建筑（包括智能化住宅小区），已成为数字化城市的信息站点，要实现信息共享，必须实现控制网与信息网的纵向集成，即控制网与TCP/IP的以太网集成。各子系统（空调、给排水、供电）由控制网互联再经网关接入TCP/IP以太网，或者各子系统经网关直接接入TCP/IP以太网。 由于各子系统及各现场设备通讯协议是多样化的，这两种集成模式都要开发网关，以实现协议的转换和统一，这样加大了系统集成技术的复杂性，提高了成本。有人大胆提出能否用TCP/IP协议作为一个统一的协议，各子系统及各现场设备直接接到以太网上以简化系统集成的技术难度，降低成本，使控制信号直接由以太网传输，工业以太网的概念因此被提出。 2 以太网与CSMA/CD2.1 以太网 以太网（Ethernet）1975年由美国XEROX公司研制成功，由于采用无源介质（如双绞线、同轴电缆等）来传播信息，所以以历史上把传播电磁波称为“以太”（Ether）来命名。 1980年由DEC、INTEL、XEROX三家联合推出了EthernetV2，是世界上第一个局域网规范。1983年IEEEE802委员会以DIX EthernetV2为基础推出了IEEE803，采用了CSMA/CD介质访问控制技术。 802.3是指采用CSMA/CD的网络，而以太网的标准由DIX EthernetV2定义，在不严格的情况下，可以称之为802.3局域网，也就是以太网。 2.2 CSMA/CD（Carrier Sense Multiple Access with Collision Detection，载波监听多路访问/冲突检测） CSMA/CD最早是由CSMA改进而来。 (1) CSMA（载波监听多路访问）：一个站要发送信号，首先要监听总线，以决定介质是否存在其它站发来的信号。 如果介质是空闲的，则可以发送； 如果介质正处于工作状态，则等待一段间隔后重试，当听到介质处于忙状态，CSMA有几种不同的方法处理，可得到的侦听信号：非坚持CSMA、1坚持CSMA、P坚持CSMA。 (2) CSMA/CD不但先听后发，而且还边听边发，总线上发生了冲突，而且一旦冲突被检测到，便停止发送该帧，放弃自已的帧。为了使其它站也能知道产生了冲突，监听到冲突的站还向总线上传播一个干扰阻塞信号，通知总线各站冲突已发生，这样通道的容量不致因传送已损坏的帧而浪费。随着网络负载的加大，碰撞的机会会增加，网络效率明显下降。3 工业以太网目前存在的问题现场总线是用于工业控制并为复杂而又恶劣环境的工业现场而设计的，因此对系统的实时性和响应时间有严格要求，对供电方式使用环境有特殊要求。由于以太网是为信息通信而设计的，用于工业控制存在以下问题： (1) 以太网采用CSMA/CD访问协议，这是一种非确定性的网络，对于实时性要求高的控制系统，这种不确定性将造成信息不能按要求传递。同一网段上受到CSMA/CD媒体访问控制方式的制约。所谓网段是指连在同一共享式网络总线上，可以侦听到对方发出的信息，处于同一冲突碰撞区域（指会发生冲突碰撞的区域）的工作站和服务器连成的网络区。例如在一个冲突碰撞区域中有一个工作群组（由一台服务器和多台工作站组成），当多台工作站访问一个服务器时，由于受CSMA/CD的约束，同一时刻只允许一个工作站与服务器通信，其它工作站只能等待。各工作站争抢通信信道，从而使工作站的通信产生延时，而且这种延时时间是不确定的，工作站愈多争抢通信等待时间愈长，这种情况被称为负荷愈重等待时间愈长。 若在一个碰撞域中，假设有两个工作群组，处于一个碰撞域中，第一个工作群组工作站访问服务器时，要竞争网络宽带（例如100M），另一个工作群组中所有工作站及服务器都处于等待状态而无法运行。两个工作群组要分割原有网络宽带（100M），一个工作群组工作时，另一个群组必须等待，这样不仅具有延时，而且这种延时是不确定的。由于CSMA/CD有无法预见的延时，特别在重负载下，实时数据传送更得不到保证。控制系统要有实时性保证，必须在任何时间都要及时响应，不允许有任何不确定性。因此以太网用于控制系统必须解决实时性和不确定性问题。 (2) 以太网在可靠性方面不如现场总线，现场