Design And Implementation Of Embedded Gateway Base On Intelligent Equipment And TCP/IP

Though intelligent equipment communication protocol has solved the problem of inconsistent communication interfaces among different communication power supply manufactures, it is rather limited in remote monitoring as a field device layer protocol since it was developed. On the other hand, there are lots of problems when the industrial Ethernet is applied in the field device layer for industrial control, as it enters the industrial control field in recent years. Therefore, fieldbus and industrial Ethernet will coexist for a long time. For the current status of the coexistence of multiple networks, the gateway is a solution. Based on the demands of actual project, an embedded gateway based on intelligent equipment and TCP/IP was designed to monitor intelligent equipment remotely.Firstly, according to the gateway working principle, the protocol model of embedded gateway base on intelligent equipment and TCP/IP was proposed, which provided a theoretical basis for hardware design, system software cutting and porting and application software design. Based on link layer's requirements in gateway protocol model, the system board and the interface board were designed respectively. Then, for industrial application environment and high frequency characteristics of system board, optical isolation, multi-layer PCB and multi-point grounding were applied to improving anti-jamming capability of hardware.Secondly, system software was ported and application software was developed based on the gateway hardware. Boot sequence of bootloader U-Boot was analyzed and flow chart thereof was drawn, then the U-Boot was ported to the embedded gateway board. Embedded operating system uClinux was configured and coarse-grained tailored by the make menuconfig method, and eventually the uClinux was ported to the embedded gateway board which was booted by U-Boot. A suitable operating environment was therefore built. Application software was designed based on system software. Through the theoretical analysis of process and thread, as while as the influence by TCP and UDP on system performance, multiple threads with lightweight multi-tasks and efficient UDP transport layer protocol were chosen to complete the basic functions of protocol conversion. Synchronization mechanism was added to the command thread and response thread, so that two threads accessed the shared RS-485 interface sequentially. On the comparison of unicast, broadcast and multicast theoretically and experimentally, multicast was applied to gateway to support intelligent equipment monitoring system with redundant multiple sites.Finally, the gateway was applied to intelligent equipment integrated monitoring system. In the long running time, the gateway's hardware and software showed good reliability and stability, which verified the feasibility and availability of the design.By means of the gateway, on one hand, the problem of intelligent equipment remote monitoring is solved. On the other hand, the reference value of intercommunication between industrial Ethernet and fieldbus is provided.