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• 2018-12-05 16:58發(fā)布了問答

  什么是CAN總線，CAN總線的優(yōu)勢和特點(diǎn)

  　

  296人看過

• 2018-12-03 14:07發(fā)布了問答

  隔離卡通信設(shè)備錯誤，請檢查連接線... 求解決方法，求原因

  　

  375人看過

• 2018-11-22 17:28發(fā)布了問答

  畢業(yè)設(shè)計(jì)外文翻譯，高手請進(jìn)，感激不盡！

  ResearchonIntegrationofCoalMineMonitoringandControlSystemwithFieldBusControlSystemAbstract:AccordingtotheconstructionofcurrentcoalminemonitoringandcontrolsystemsinChina，t... Research on Integration of Coal Mine Monitoring and Control System with Field Bus Control System Abstract:According to the construction of current coal mine monitoring and control systems in China，the paper proposes three kinds of applicable schemes of integrating PLC and DCS systems with field bus technology to digitize the system and to improve the flexibility and extent of the system.Essentially，the paper introduces the integration of FCS on I/O layers.Based on a real coal mine safety-monitoring and control system applied with a CAN field bus，the major technology of system relays and extensions is discussed.We believe that one of the most applicable methods is currently replacing the connection between function-stations and field-sensors with a CAN bus on I/O layers for system integration. Key words:monitor and control;field bus control system;CAN;integration 1 Coal Mine Monitoring and Control System and Field Bus Technology As one of the most important methods to improve modern management and production efficiency in coal mines，monitoring and control technology have been widely adopted to maintain safety in coal production.Taking advantage of foreign technologies from the 1980’s，coal mine monitoring and control systems have expanded rapidly in China.At present， automatic control has come into use in most large-scale coal mines，which greatly improved production efficiency and safety and lowered costs. In China，most sub-systems of coal mine systems work independently.They follow a DCS system structure of three layers(center layer，sub-station layer and sensor layer)which consists of a tree to-pology.They are composed of sensors，sub-stations on or under the ground，center stations，multiple controllers and display terminals(Fig.1).They work with analogue signals of 4–20 mA or 200–1000 Hz. Each coupled cable can only act as one line for transmission[1]. Currently control networks have been developed for digitalization and networking.Because traditional analogue signals of 4–20 mA or 200–1000 Hz can only carry simple measurement information and con-trol signals，the communication rate is restricted. Therefore，it is necessary to digitalize and network the entire monitoring and control system. Fig.1 Traditional Structure of Coal Mine Monitoring and Control System 展開

  491人看過

• 2015-07-30 02:23發(fā)布了問答

  為什么網(wǎng)橋記錄的地址是MAC地址而不是IP地址？

  使用表示區(qū)域的IP地址，轉(zhuǎn)發(fā)表的改變不是更少嗎？... 使用表示區(qū)域的IP地址，轉(zhuǎn)發(fā)表的改變不是更少嗎？ 展開

  577人看過

• 2014-11-04 02:03發(fā)布了問答

  無線150mb網(wǎng)橋?qū)嶋H吞吐量是多少

  　

  419人看過

• 2013-12-09 17:09發(fā)布了問答

  IDE設(shè)備在一條線上為什么只能接2個？

  　

  485人看過

• 2013-07-01 00:30發(fā)布了問答

  無線網(wǎng)橋是否能通過trunk透傳vlan？

  無線網(wǎng)橋是否能通過trunk透傳vlan？A交換機(jī)的trunk口連網(wǎng)橋A，B交換機(jī)的trunk口連網(wǎng)橋B，AB網(wǎng)橋通過無線連接，請問AB交換機(jī)能通訊嗎？... 無線網(wǎng)橋是否能通過trunk透傳vlan？A交換機(jī)的trunk口連網(wǎng)橋A，B交換機(jī)的trunk口連網(wǎng)橋B，AB網(wǎng)橋通過無線連接，請問AB交換機(jī)能通訊嗎？ 展開

  625人看過

• 2013-05-06 07:08發(fā)布了問答

  請問，CAN總線在國內(nèi)的現(xiàn)場總線中市場占有率大概為多少？

  　

  302人看過

• 2012-05-22 16:22發(fā)布了問答

  視頻監(jiān)控系統(tǒng)多少路是什么意思

  　

  607人看過

• 2012-04-25 00:16發(fā)布了問答

  求用網(wǎng)線堆疊交換機(jī)的方法？對網(wǎng)絡(luò)有什么影響？

  　

  636人看過

• 2010-11-18 01:33發(fā)布了問答

  什么是二層交換網(wǎng)絡(luò)？

  　

  463人看過

• 2008-12-05 15:36發(fā)布了問答

  監(jiān)控用視頻線SYV-75-5

  監(jiān)控用視頻線SYV-75-5代表什么意思，一般用什么型號的線。發(fā)泡線或PE線是什么意思。... 監(jiān)控用視頻線SYV-75-5 代表什么意思，一般用什么型號的線。發(fā)泡線或PE線是什么意思。 展開

  506人看過