Research, Measurement And Control Network Based On Can Field Bus

The development of the control system put forward higher demands on the openness, interoperability and bottom layer functions of the control network. The appearance of field bus technology satisfied the demands and caused a revolution of the control system. It will be the development trend of the control system because of its outstanding advantages. CAN bus has the advantages of high-reliability, real-time and low-price, so it is used widely. In this paper, we mainly discussed the network based on CAN bus, the main work is as follows:First, expatiated on the characteristic, communication principle of CAN bus; Provided the overall design plan, the structure feature and working principle of the control net based on CAN bus; introduced the circuit principle, technical criteria and operation instructions of the intelligence control device; presented the systematic structure and operation principle of the USBCAN interface card.Second, a new protocol for user layer communication which is named QucanA is presented, this protocol is based on "order + parameter ", adopt the function of dual filter and the form of standard frame, support broadcast, group's radio and point-to-point communication.Third, the communication software based on the protocol Qucan_A between master nodes and slave nodes have been designed. The slave-nodes communication software mainly includes three modules: the initialize of CAN intelligence control device, the transmission and the interrupt reception of the message, the protocol realization of the slave nodes. The master-node communication software mainly includes: the initialization of the master node, the transmission and reception of the message, the protocol realization of the master node, the man-machine interface of the network.Fourth, the master node driver with two interfaces has been designed, it can exchange data with USBCAN interface card and other application softwares. In addition, the configuration and data management of the network have been designed.Fifth, the user I/O subfunctions of the slave node have been designed, the subfunctions mainly include: A/D, D/A, D/I, D/O.Sixth, based on the current situation of the transformer substation and the design request, a monitoring example of the transformer substation has been realized. The main modules include: the monitoring interface of the transformer substation, the main hookup, history alarm, trend display, and etc. Consequently, it further verifies the advancement...