Research On Multi-MCU Automatic Detection Of Network

As the information and network technology develops, automatic detection network has become a key technology in modern industrial control systems. Network-based industrial control systems are getting more and more complicated, it has become a popular problem in recent control system about the method of achieving a flexible network with automatic detection ability.Programmable Logic Controller (PLC) occurred with the requirement for industrial production. It has found wide application in various areas of industrial production. PLC is an important role in modern industry. With the enhanced network capacity, control functions and scope are extended for PLC. The remote control of PLC network has received great attention recently. Therefore, in this paper, two aspects, i.e., "device-independent" designing and web-based network are discussed, and a web-based "device-independent" remote monitoring system is proposed.In the small-scale industrial control systems, peripherals like programmable controllers are widely used. The most commonly used PLC is the Panasonic, the Fuji, and the Siemens. A microcontroller system is also widely used. These PLC and microcontroller subsystem are equipped with different communication protocol, ports addressing and memory modules. This makes the exchange of PLC of different manufacturer impossible. When the PLC product is exchanged with different maker, communication protocol needs to be re-written. To cope with such problem, a "device-independent" software programming for control system is proposed. Since PLC manufacturers use different communication protocols, port addresses, memory modules and other information change with different manufacturers, a uniformed XML format is applied in our system for simplicity. Device's physical address and system logical address matching and communication protocol conversion are realized by XML mapping. Peripheral port alteration and protocol modification are realized by XML file modification. Therefore, no code modification or system maintenance is required.Instead of conventional RS-422/485 communication protocol, the Ethernet network, a faster and reliable network, is used in our system for the communications with host or other controlling system. Although fieldbus-based industrial control network occupies some market share currently, the SCM system and the Ethernet networking technology has its broad application prospects. In the thesis, an MCU-based embedded web server is realized. Based upon the specialty of embedded systems, all protocols and services are specially designed to cope with limited resource of embedded system. The protocols including ICMP, IP, TCP, UDP, and HTTP are realized in our system.Based on the above design ideas, embedded web works as a network node in the network. Information and system parameter setting are realized by web "post". Therefore, remote controlling and data acquisition is implemented.The system applies several different manufacturers of the PLC for "device-independent" test and remote web communication test. It is proven that the proposed method is feasible.