| CAN bus and PROFIBUS DP bus are extensively applied to more and more control system, and the connection technology of them is dicussed in this paper. In order to realize the gateway, one sole-CPU structure is traditionally used, and here a double CPU structure is given. In the former structure the CPU is not only used to realize the transmission and control of the bus dada, but also used to translate the protocol. So the CPU is busy and the software is coplex. For the later the CPUs are used to deal with the data of the both buses in the system, and it has many advantages such as high -speed communication, simple software and strong resisting ability, and so on. The gateway involved in the paper is based on the latter.The characteristics of the buses are introduced in the paper. CAN supportes distributed control and real time control, and it is a kind of serial net. It permits polymaster stations, and the stations are of the same strcture but priority and communication methods are flexible. PROFIBUS DP is a kind of multi master-slave station structure bus, and the communication between the masters is Token way, and subordination between the master and slaves. Based on the analysis, we reach a conclusion that the gateway between the CAN and PROFIBUS DP is unidirectional.Here is a design scheme, following which a gateway between PROFIBUS DP and CAN is made. The gateway realizes the interconnection between two widely used fieldbus systems —PROFIBUS DP and CAN.The software and hardware of the gateway is introduced with an emphasis. The gateway provides the two bus interfaces, one for CAN bus, the other for PROFIBUS DP. It can deal with the data of the both the buses.the software and hardware is given.At last the gateway is put into fieldbus to test its quality, and some advice are given to improve it. The characteristic of the text is that double CPU is used to realize the connection of two different buses. |
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