【作者】 王亮；

【导师】 王立忠；

【作者基本信息】 广西师范大学 ， 电路与系统， 2012， 硕士

【摘要】 总线继电器指的是具有总线通信功能的继电器。在过去的几十年里,用电设备的故障预防通常使用保险丝和断路器等防护装置,这些装置的特点是比较被动,比如出现故障无法预警,出现故障诊断起来比较困难,如此一来,在一些特殊需要的地方,比如舰船、航天飞机、车辆等等,无法满足它们的需要。这样就促成了在传统的继电器中引入总线技术趋势。另外,由于总线继电器可以提供信息查询、故障记录、保护参数设置等功能,很大程度上方便了用户进行系统配置。传统的继电器中引入总线技术,好比继电器上多了双眼睛,使得用户能更好的把握继电器的工作状态。总线继电器可以将具有智能化、网络功能的电器节点有机的组合起来构成一个比较先进的电气负载管理系统,可以对系统发出的指令进行逻辑切换、信息反馈,实现数据采集、过载保护、状态检测、故障记录等功能。这种先进的负载管理系统有很多优点,首先是减轻系统的重量,从而减小设备的体积,这主要体现在总线继电器是安装在距离负载比较近的地方,通过总线进行控制和信息反馈,这样就减少了电缆和连接器的使用。第二便是提高系统的可靠性,主要是总线继电器易采用隔离、冗余和多种错误检测与故障恢复机制,防止系统出现死机的情况。第三便是系统的可维护性,这主要体现在维护人员能很快的找到故障节点,并及时排除故障。第四便是提高的可扩展的可能性,这只需要对软件进行必要的修改,便可以构造成新的节点。这是一般继电器所不具备的。总线继电器除了具备传统继电器接通和关断的能力外,还具其它功能,这表现在以下几个方面：它可以利用总线进行通信,比如它的开通和关闭能依靠总线的控制指令实现,这样就改变了以前系统点对点的控制方式,减少了对电缆和连接器的依赖,大大减轻设备的重量；具有负载电流电测功能,这主要表现在可以通过查询总线来实现负载电流的实时监测；具有负载电流过载保护和短路跳闸功能,而且跳闸的阈值是可变的；具有触点状态监测功能,这主要通过查询总线指令来实现触点状态的检测；具有历史工作记录查询功能,比如继电器的过载情况、短路情况、触点工作状态等可记录在继电器中,而且即使系统掉电,这些数据也不会丢失,便于故障及时预防、诊断及维护。微机系统中经常使用的总线有三种,分别是内部总线、系统总线以及外部总线。内部总线的作用是将处理器和与其相近的芯片连接起来；系统总线的作用是实现系统板和插件板之间的通信；外部总线的作用是建立微机和外设之间的连接。常用的总线有RS232、RS485、CAN总线。对于RS232总线(双工通信),由于RS232是单总线数据传输,不可避免的会受到共地噪声和共模干扰的影响,所以通常情况下用于近距离通信,正常情况下不能超过20m。RS485使用的是平衡的发送方式和差分的接收方式,故可以减小共模干扰对通信的影响。此外,由于总线收发器的精度比较高,可以检测出来比200mV还低的电压,如此以来,使得恢复千米之外的信号变成可能。RS485的工作方式是半双工,不管什么时候,仅有一个节点的状态是发送状态,所以要想实现发送的过程,硬件电路上就需要一个通信使能信号。所以文中将使用性能良好的CAN总线。CAN总线是一种现场总线,它在以下串行通信网络中应用比较广泛,比如分布式控制、实时控制等等。基于CAN总线的分布式控制系统在以下方面具有明显的优越性：仅需要两信号线便可以实现与外部的连接,同时具有错误探测的功能,内部还具有错误管理模块。围绕总线继电器的优点,文中将对CAN总线的协议进行研究,然后制定文中系统的通信协议；根据通信内容的要求,设计符合要求的单片机外围硬件电路；结合制定的通信协议和预期功能设计相应的软件程序；为增加系统的可靠性,研究影响系统可靠性的因素并采取对应措施；为实现系统远距离通信,研究影响系统通信距离的因素进一步完善系统；为实现多节点通信,研究制约总线可挂接节点数目的因素。通过以上工作来设计一个总线智能继电器节点。更多还原

【Abstract】 Relay based on Bus is a relay with bus communication function. In the past few decades, People make use of the fuse box and breaker to prevent electrical equipment from power-failure. But these protective equipment are characterized by passive.it is difficult to warn and diagosis when have some problem.unabe to meet special need,such as ships,spacecraft,vehicles etc. so relay base on bus becomes a kind of trend.Relay base on bus provides with information qurey,error-record,saving important,parameter. It is esay for help users to configure the system.This allows user to grasp the state of the realy.Advanced electrical load management system is compose with intelligent,network-enable appliances node by relay based can bus.According to the command of the system,carry out the logical switch,feedback,data collection,overload protection,state detection,fault records and so on. This advanced load management system has many advantages,first of all,reducing the weight of the system,reducing the size of device,not relay on cables and connectors.second,the function of load current measurement can be achieved by querying bus command. Third,have the function of load current overload protection and short circuit tripping capabilities,at the same time the trip threshold is variable.Forth,the detection of the contact state is achieved by querying the bus command.fifth,have the historical work records search function,such as the state of relay overload,the state of short circuit,the state of contact can be recorded in the relay,these data do not lose when meet with power-failure.It is helpful to failure protection,diagnosis and maintenance.There are some bus in the computer,for example internal bus,systerm bus,external bus and so on.internal bus is used to connect perioheral chips with processors.systerm bus is used to connect the various plug-in bord with sistem board. external bus is used to connect computer with external devices.At present,RS232,RS485,CAN are popular bus.RS232is a single-ended signal transmission,there is common-mode interference communication distance is short.communication distance is less than20m.RS485make use of the technology of the balance-send and differential receiver,it has the ability of suppress common mode interference. Bus transceiver has high sensitivity,can detect the volatage lager than200mv.transmission signal can be recovered in the1000m,it has half-duplex mode,there is only node in the sending state at any time,therefore transmit circuit need enable signal.so we will get use of can bus with excellent performance in the paper.CAN bus is belong to the field of fieldbus,support for realtime control of distributed control and serial communication network.compared with RS232,RS485,CAN bus has obvious advantages,there is only two lines in the system.there are error detection and management module in the system.According to the advantage of the BUS relay and the protocol of CAN bus,design the communication protocol of the system;according to the requirements of communication context,design the single-chip peripheral hardware circuit;design corresponding software;study the factors affecting the reliability of the system and get use of corresponding measures;study the factors of affecting remote-distance communication;study the factor of affecting the number of nodes.above all, design the Bus intelligent relay.更多还原