Research And Design Of Integration Infrastructure For Heterogeneous Industrial Control Networks

In recent years, modern industrial production processes became increasingly complex, so that the existing cable network systems have been difficult or impossible to meet the communication needs of industrial field devices. At the same time, with rapid development of the wireless communications and network, their applications have gradually entered into the modern industrial manufacturing field. However, wireless communications and network technologies for industrial applications are not mature and well. So they can not completely replace wired communication systems in industrial field in the future for a long time. Therefore, it is particularly essential to research on integration of wireless and wired communication networks. IEEE 802.15.4a is the latest wireless communication protocol standard for industrial applications. The Chip Spread Spectrum technology adopted by IEEE 802.15.4a can effectively restrain the noise of industrial environments and electromagnetic interference. In order to promote and facilitate the practical application of the wireless communication networks based on IEEE 802.15.4a in the industrial control field, in this paper, we start to research on integration infrastructure of the IEEE 802.15.4a wireless communication networks and the wired networks in industrial field.In this paper, the technologies of IEEE 802.15.4a, industrial Ethernet, and integration of wireless/wired heterogeneous networks are introduced firstly. Then a MAC layer protocol of token-based wireless industrial control networks(WICN) is presented. And the protocol frame format, network rules and operational mechanisms of WICN are elaborated. Then we propose an integration scheme on transport layer for token-based WICN and wired Ethernet, including the data storage model based on shared data area and the mechanisms of protocol conversion and data forwarding based on data mapping. The protocol converter based on the integration architecture above includes wireless industrial control networks(WICN) master module and TCP server module. And the two modules have their own separate input buffer and output buffer. The protocol converter also sets up a shared data area used for data mapping between the data buffer of WICN master module and the data buffer of TCP server module, which includes uplink data area and downlink data area. Finally, the protocol converter based on ARM9(S3C2440) and WinCE5.0 is designed. Then we set up the test system, and complete the test to the protocol converter.The integration infrastructure presented in the paper can be used to realize the integration of token-based WICN and wired Ethernet and provide free and flexible data exchange service for each site in the heterogeneous industrial control network.