Research And Design Of Special Transformer Acquisition Terminal Based On Ethernet Communication

Special transformer acquisition terminal is acquisition device aim at users who have special transformer in the power user electric energy data acquire system. It's between host and energy meter. Its good performance is directly related to the normal operation of power user electric energy data acquire system.The aim of this paper is to complete a special transformer acquisition terminal who has a lightweight operating system entrusted by BIA Technology Company.The main character of the special transformer acquisition terminal is it communicates with the host through Ethernet. So the first focus of this paper is the implementation of TCP/IP protocol stack which is used for Ethernet. The main content of TCP/IP protocol stack in this paper is as follows:1. The embedded TCP/IP protocol stack is Choosed, the code of choosed protocol stack LwIP is analyzed by module in order to deeply understand the process of LwIP and prepare for the improvement.2. The improvement plan of LwIP for special transformer acquisition terminal is given. It includes the improvements of transmission queue, route redirect of ICMP protocol, and congestion control algorithm of TCP protocol;3. Codes of operating system modeling layer is composed and LwIP is grafted to theμC/OS-Ⅱoperating system.4. Ethernet driver codes are composed according to the Ethernet controller of LPC2378 and the phy DM9161A;5. The Ethernet communication is tested through physical layer and link layer test, TCP transfer test and so on.The second focus of this paper is the design of the application software. Application tasks are partitioned according to the application design principle of UCOS-Ⅱand the functions of special transformer acquisition terminal. The priority of each task is also determined and flow.charts of some tasks are drawed.In addition, the hardware of the special transformer acquisition terminal is introduced; circuit diagrams of some modules are drawed; the software development platform is builded, its kernel is GCC complier and it bases on SmartARM2300 development board; the UCOS-Ⅱoperating system which is based on LPC2378 is builed.Through above, the design of the main part of the terminal is completed, and the kernel test about Ethernet communication is done. The results show that Ethernet communications can be successfully established.