Key Technologies For Embedded Networked Measurement And Control System, And Achieved

This article presents two kinds of structures of remote measure-control system based on embedded Web server, aiming at different kinds of measure-control scope, performance and security. Compared with traditional measure-control system built on local bus such as RS232 and GP1B, theses structures have the characteristic of wider measure-control scope, more equipments supported and stronger adaptability. Furthermore, these structures have uniform user interface, can be updated easily and have no relation to client platform. The design and realization of each primary modules are discussed in detail:(1) OS-embedded network instrument is made up of 32-bit MPU Mc68EZ328 and embedded operating system uClinux. Web server is set up to realize remote measuring and controlling by programming with socket interface.(2) None-OS-embedded network instrument is designed with an 8-bit MCU C8051F020 and a network controller RTL8019AS. TCP/IP protocol and Web server is carried out by programming. Using this method many low-end MCU can be connected to Internet successfully.(3) The hardware circuit of double-interface gateway based on embedded system is designed in this article. NAT gateway is configured with a PC driving double Ethernet interfaces. Using iptables, network-address translation can be realized so as to resolve the problem of address exhausting in embedded Internet age.(4) Single-interface gateway, the realization method of which is brought forward for the first time, binds two IP addresses to one Ethernet interface and realizes NAT with custom program. This method simplifies hardware, costs less and can be used in small measure-control system with low request of security.(5) Two realization methods of embedded Web Server are presented and validated in OS-embedded and None-OS-embedded network instruments.