Design Of Collector For Power Automatic Meter Reading Based On Ethernet

Automatic meter reading is a method of reading and processing data automatically withcomputer and modern communication technology. It is the requirement of improving the automaticlevel of energy company and the necessity of rapid development of computer and communicationtechnology. In order to adopting the bloom of broadband networks and data traffic well, this paperhas put forward a design of collector based on Ethernet ,which has great advantage of speed,stability and accuracy, compared with common collector adopted GPRS/CDMA.Firstly this paper gives hardware solution and software solution according to the function ofcollector. The hardware adopt modular design which is used usually in embedded system designand divided several modules: power module, real time clock module, storage module,RS485interface module, Ethernet module, infrared interface module, watchdog module and system ledmodule.STM3F207 has been chose to be MCU, because strong processing power can improveenough operating resources for software and protocol stack. The software is FreeRTOS operatingsystem and LwIP protocol stack which contains TCP/IP protocol for Ethernet. Otherwise, five-viewapproach has been applied in system architectural design, in order to dividing function betweensoftware and hardware ,and making sure design target.Secondly this paper introduces the hardware design details and the transplantation of LwIP.The hardware design details include not only chips and Circuit diagram, but also some EMC designwhich can make collector adopting its work environment easily. The interfaces of hardware havebeen initialized by MCU’s firmware. The transplantation of LwIP have two steps: first step ,realizethe operating system emulation layer, which can make LwIP connecting with operating system;second step, initialize LwIP, including Ethernet interface’s hardware driver, which can make LwIPconnecting with hardware.Finally this paper introduces the function test and performance test of the Ethernet thatcollector uplink communication channel in order to inspecting the design. Results show that thecollector can set up reliable connection with the master station through the Ethernet and the designtarget has realized.