The Research Of Embeded Network Gateway Based On ARM Processor And UClinux

With the rapid development of INTERNET, we are easier to release and obtain information through INTERNET. If we use INTERNET in industrial monitor field,we will cost less and monitor farther. But industrial devices don't support TCP/IP ,So we study a network gateway to realize the communication between INTERNET client and industrial PLC.It can use RS-485 interface and the computer link protocol to communicate with the mitsubishi PLC, can read and write the PLC.It realizes a server based on Linux Socket, many clients can browse the server but only supervisor can control the server.It realizes the communication between PLC and INTERNET client which makes client can browse PLC and control PLC.It supports user configuration , user can set gateway's IP ,port, and netmask and customize it.We design hardware and software to realize above functions. In hardware ,design embedded circuit board based on ARM processor including the minister system , RS-485 circuit , network interface , user configuration interface and some LED circuits and so oh . In software , customize uClinux , build debug environment. Then we discuss the whole gateway software from three processes:PLC communication process, network communication process and user configuration file download process. And we use inter-process communication and inter-process sychronization to realize data communication and protocol conversion of different protocol interfaces.The gateway defines simple and credible application protocol and uses the protocol to write monitor program ; defines the format of configuration file and the protocol of configuration file download. It provides a good network monitor solution for user.