Ethernet , controlnet and can , the three control bus , which are in common use , are analyzed . by comparing their characteristics of function of the mac sub - layer and considering the requirements of control systems on - board , can bus has been chosen in the communication system built in locomotive 分析了ethernet ， controlnet ， can三种典型的控制总线，通过比较分析其mac子层的性能特点，结合车载控制系统要求，采用can总线作为系统的通信总线。
Advantages of std bus and structure of pc / 104 bus are referred to design the user - bus , which uses three bus structures , i . e . address bus ( ab ) , data bus ( db ) and control bus ( cb ) . it is well compatible , and the applying system has flexibility and common use and is convenient to extent for users 该总线采用三总线结构，即地址总线( ab ) 、数据总线( db )和控制总线( cb ) ，具有良好的兼容性，从而使应用系统具有灵活性和通用性等特点，方便用户对应用系统进行扩展。
A new full - wave measurement circuit structure is put forward that would increase distribution automation system reliability and veracity . the distributed protection and monitoring unit in this paper can instead of general instruments of low voltage distribution system . it not only combines ampere meter , voltage meter , active power meter , reactive power meter and power meter , frequency meter into a meter , but also increases monitoring position switch , control bus switching alternately and monitoring energy 本文研制的保护和测控单元，可替代低压配电系统中所使用的常规仪表，将原来回路需要的电流表、电压表、有功功率表、无功功率表和功率因数表、频率表简化为一块表，并增加了位置开关量检测，控制母线投切和电度监测功能，从而极大的简化了低压配电二次仪表设计、安装调试，提高了运行、维护和管理水平。
Then the system architecture is further optimized by ways like : the normal and test data interfaces , control bus , configurable design based on i2c , using simplified emcu . all the optimizations improve the suitability , scalability , flexibility and maintainability of the whole system architecture 然后对系统的结构进一步的优化：数据处理模块带有正常与测试的两组数据端口，基于总线的管理控制方式， i2c总线接口的芯片可配置设计，采用简化emcu的嵌入式系统。
Firstly , this paper makes a detailed study on the field control bus system ( pcs ) , including the characters of pcs by comparing fcs and dcs , model networking of pcs and several popular field bus , then put forward a question for discussion combining embeded internet technology and field bus and measure and control networking model based embeded internet technology is constructed . secondly , it studies embeded system including the core of hardware ? mbeded microprocessor and real time operation system . thirdly , the method of realizing embeded internet is discussed for emphasis , and difficulty of ehernet application in industry measure & control system is analysed . an instance of measure & control networking system based embedded ip is given . finally , the author designed a networked remote video surveillance system based embedded web server , c / os - ii is sacled and ported into the embedded microprocessor at89c51 . based on the c / os - ii rtos , tcp / ip protocol suite and application program is designed in detail . the system w orks well that improves that the embedded internet technology will be widely used in modern measure & control networking system and has extend values 本文首先分析了现场总线系统( fcs )与传统集散控制系统( dcs )相比具有的特点、 fcs的网络体系结构，介绍了几种流行的现场总线，提出了将嵌入式internet技术结合现场总线构建现代测控网络的课题；在此基础上，构建了基于嵌入式internet技术的测控网络结构模型；深入研究了嵌入式系统的核心硬件?嵌入式微处理器，通过对比普通操作系统，描述了嵌入式实时操作系统的特点；重点研究了实现嵌入式internet的四种实现方法，并分析了以太网在工业测控系统中应用的难点，给出了一个基于嵌入式ip的网络测控系统实例；最后，研究与设计了一个基于嵌入式web服务器的远程网络视频监控系统，该嵌入式web服务器利用目前成熟的嵌入式实时操作系统c / os - ，通过对c / os -进行适当的裁剪、修改与移植，在at89c51嵌入式微处理器上实现了tcp / ip协议栈及应用程序，系统的成功运行证明了本文研究成果的有效性，也表明嵌入式internet技术在现代测控网络系统中具有广阔的应用前景和推广价值。
In support of the chief executive s policy address in 1999 on environmental improvements , transport department is actively participating in this aspect which includes identification of environmental improvement measures by the third comprehensive transport study ( cts - 3 ) , conversion of diesel to liquefied petroleum gas ( lpg ) taxis , exploring alternative fuel buses , rationalization of franchised bus fleet , controlling bus numbers , improving vehicle emission , stepping up vehicle maintenance and implementing pedestrian schemes 为配合行政长官1999年施政报告内有关改善环境的措施，运输署现正积极进行这方面的工作，包括探讨由第三次整体运输研究报告所提出的改善环境措施、由柴油的士转用石油气的士、研究使用另类燃料的巴士、重组专营巴士车队、控制巴士数目、改善车辆排放废气的情况、加强车辆维修工作、实施行人环境改善计划。
Adopting the method of top - down , the virtual memory is divided into memory mange related unit ( segment unit and page unit ) and protection mode related unit ( protection test unit , debug test unit and exception detect unit ) . data buses and control bused are designed separately for all of the units . vhdl codes are written and simulated Amex86的虚拟存储器采用自顶向下的设计方法，把虚拟存储器划分为地址管理相关单元(又包括分段单元和分页单元) 、保护模式相关单元(又包括保护测试单元、调试异常单元利异常检测单元等) ，分别确立其数据通路和控制通路，完成了vhdl的编码和仿真工作，通过测试程序仿真验证了其功能的正确性并测定了基本性能。
In support of the chief executive s policy address in 1999 on environmental improvements , transport department is actively participating in this aspect which includes identification of environmental improvement measures by the third comprehensive transport study cts - 3 , conversion of diesel to liquefied petroleum gas taxis , exploring alternative fuel buses , rationalization of franchised bus fleet , controlling bus numbers , improving vehicle emission , stepping up vehicle maintenance and implementing pedestrian schemes 为配合行政长官1999年施政报告内有关改善环境的措施，运输署现正积极进行这方面的工作，包括探讨由第三次整体运输研究报告所提出的改善环境措施、由柴油的士转用石油气的士、研究使用另类燃料的巴士、重组专营巴士车队、控制巴士数目、改善车辆排放废气的情况、加强车辆维修工作、实施行人环境改善计划。
