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RS-232至RS-485/RS-422接口的智能转换器 总被引:2,自引:0,他引:2
详细地介绍了如何从 RS-232信号线上高效率地产生电源,如何实现 RS-232接口与RS-485/RS-422接口的智能转换,同时,也给出了具体的硬件设计及软件设计方法. 相似文献
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许平峰 《计算机光盘软件与应用》2011,(10)
为满足RS-232全信号(RXD、TXD、RTS、CTS)在长距离上传输的需求,提出了一种将RS-232信号进行转换,实现长距离传输要求的一种方法.该方法包括了串行接口信号转换电路设计和信息长距离传输实现过程,并重点对一些关键技术进行介绍. 相似文献
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欧隆利 《自动化与信息工程》1998,(1)
给出RS-485,RS-422从站主动呼叫所产生总线竟争问题的解决方案.该方案特点是可实现各站间互为主动方的通信,通信信号线少,结构简单,特别适合远距离的分布集散控制系统. 相似文献
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引言 RS-485收发器采用平衡发送和差分接收,因此具有抑制共模干扰的能力;加上接收器具有高灵敏度,能检测低达200 mV的电压,故传输信号能在千米以外得到恢复. 相似文献
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RS-232/RS-485无源转换电路设计 总被引:2,自引:0,他引:2
李继晟 《单片机与嵌入式系统应用》2004,(7):75-76
RS-232、RS-485都是串行数据接口标准。由于它们的接口电路简单,通用性比较好,所以在控制领域有着广泛的应用。RS-232和RS-485有着各自的优缺点:RS-232是低速率串行单端标准,采取不平衡传输方式(即所谓单端通信),收、发端的数据信号是相对于信号地的电平而言,其共模抑制能力差, 相似文献
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介绍PC机与西门子PLC在船舶电站自动化系统中的通信方式,利用VB6.0中MSComm控件实现了PC与PLC的串行通信,该通信系统简单、可靠,有较高的使用价值. 相似文献
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Modbus协议由于其开放性、透明性、低成本和易于开发等特点,已成为当今工业控制领域最流行的通讯协议之一。RS-485串行通讯总线是一种性能优良的现场总线,采用RS-485总线作为网络通信的物理层,使用Modbus通信协议来设计智能仪表的通迅程序,增强智能仪表的互换性,同时解决了上位计算机系统开发数据通讯驱动程序困难的问题。 相似文献
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Modbus是应用于电子控制器上的一种通信协议。该文主要介绍了以上位机PC为核心的基于Modbus通信协议的建筑能耗监控系统的设计,详细阐述了基于Modbus RTU规约的电力参数采集显示系统的软硬件组成和实现。VC++6.0开发环境下编程实现了与下位机的通信,并利用ADO访问SQL数据库,实现了对采集来的数据进行存储、绘图等。 相似文献
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Using a high temperature Calvet microcalorimeter, the molar enthalpy of formation of liquid quaternary and quinary alloys have been carried out at 730 K along several sections belonging to their barycenter. The well-known models for extrapolation ( Kohler, Muggianu, Toop, Hoch-Arpshofen and Mathieu ) adapted to the n-component systems have been used to predict the enthalpy of formation of the liquid systems : Cd+Ga+ln+Sn, Cd+Ga+ln+Zn, Ga+ln+Sn+Zn and Cd+Ga+In+Sn+Zn. Experimental and calculated results have been compared. 相似文献
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常循环码是一类重要的线性码,由于其纠错性能易于分析,因而广泛应用于实践中,同时,利用有限环上常循环码还可以直接构造最优线性码。定义了有限非链环[Fp+uFp+vFp]上[(1+u+v)]-循环码的相关概念,讨论了其生成多项式;引入了一种新的Gray映射[?],证明了该环上[(1+u+v)]-循环码在此Gray映射[?]下的[p]元象是一个长为[2pn]的2-准循环码,并由此构造出了两个最优二元准循环码。 相似文献
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师小霞 《数字社区&智能家居》2009,(29)
随着社会信息化程度的不断提高,越来越多的个人、团体需要甚至是企业级的应用程序。而Sun公司的JEE能很好地满足这种需求。JEE具有高速反应、安全性高、可扩展性好和集成化等优点,越来越多地软件开发人员认可和使用。然而开发人员在开发系统之前要做的重要工作就是要搭建一个JEE的开发环境,该文通过在XP下用jdk+tomacat+eclipse+mysql的安装、配制与调试,验证了这种方法是快速有效的。 相似文献
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In this paper, we study quantum codes over \(F_q\) from cyclic codes over \(F_q+uF_q+vF_q+uvF_q,\) where \(u^2=u,~v^2=v,~uv=vu,~q=p^m\), and p is an odd prime. We give the structure of cyclic codes over \(F_q+uF_q+vF_q+uvF_q\) and obtain self-orthogonal codes over \(F_q\) as Gray images of linear and cyclic codes over \(F_q+uF_q+vF_q+uvF_q\). In particular, we decompose a cyclic code over \(F_q+uF_q+vF_q+uvF_q\) into four cyclic codes over \(F_q\) to determine the parameters of the corresponding quantum code. 相似文献
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Software agents are being deployed in increasing numbers to help users find and manage information, particularly in open environments such as the Internet. For the most part, they operate independently and are typically designed to be aware only of their users and the environment in which they perform their tasks. Thus, they fail to take advantage of each other's abilities or results. For example, a shopping agent might periodically access several online databases to find the best price for a music CD and then purchase it if the price falls below its user's threshold. Other agents might be tracking prices for the same CD, duplicating each other's work. Similarly, if your agent and an agent for the person in the next cubicle are both browsing the same Web site, two identical data streams arrive on your LAN, using twice the bandwidth actually needed. To be more effective, agents must be aware of each other; therefore, they must acquire models of each other. One way to do this is by exchanging messages. A second form of awareness involves the state of the agent's own environment, including characteristics of the computer on which it is executing and its network connection. A third involves self awareness: knowing its name, age, ontology, goals, areas of expertise and ignorance, and reasoning abilities. Finally, the agent should be aware of its physical environment. The article explains how software agents can develop awareness 相似文献
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研究了HSSA(Hibernate+Spring+Struts+Ajax)体系架构,并结合一个具体的企务通系统实例以开源框架Spring为处理业务逻辑的核心,向下整合Hibernate进行持久层访问,向上整合Struts和Ajax完成与用户的友好交互.实际应用表明,HSSA整合架构发挥了各框架在各个层次上的优势,降低了开发的难度,在可维护性、交互性上较之一般的J2EE开发有明显的优势. 相似文献