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1、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 f

2、or 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.） network （TCP / IP Ethernet）, in order to achieve integr

3、ated 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 nee

4、d 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 a

5、chieve 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 integr

6、ation 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 me

7、dium （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

8、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, i

9、ts 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-carri

10、er 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

11、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

12、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 s

13、ignal 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 Industr

14、ial 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 desig

15、ned 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

16、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 confl

17、ict 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

18、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,

19、 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 broadba

20、nd 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 sol

21、ved 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, gr

22、ounding 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 fe

23、asibility 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 improv

24、e 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）

25、 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 por

26、t 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 netwo

27、rk 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 chann

28、el .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 acce

29、ss 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 technolo

30、gy 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 large

31、ly 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 improvin

32、g 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 a