Application and analysis of industrial Ethernet in modern industry
I. Overview
As we all know, in the enterprise information system, Ethernet has become the de facto standard network, industrial real-time control is an extension of traditional Ethernet, to help users build a more open integrated industrial automation and information network. Industrial Ethernet technology, which is a combination of standard Ethernet and common industrial protocols. First of all, it meets the real-time requirements of industrial automation, the original Ethernet used CSMA/CD can not meet the needs of industrial real-time, when the main use of fieldbus and token ring network, with the improvement of technology, In terms of real-time performance, the switch has met all industrial application requirements from high-precision time synchronization (+-100ns), distributed servo control, discrete control, process control to security systems, and supports on-site and remote monitoring, diagnosis and configuration. Of course, EtherNet/IP products can also use other standard Ethernet services such as HTTP, SNMP, etc. This means that industrial automation and enterprise information systems are more directly integrated, for example, without additional programming, the relevant personnel can easily configure, diagnose and monitor factory equipment through a web browser. In addition, EtherNet/IP also makes provisions from EMC, installation protection levels, to ensure the strict industrial environment adaptability of EtherNet/IP products.
Second, the characteristics of industrial Ethernet technology
2.1 Communication certainty and real-time
The biggest feature of industrial control network is that it must meet the real-time requirements of the control function, that is, the signal transmission must be fast enough and meet the certainty of the signal. Real-time control often requires accurate and periodic refreshes of data for some variables. Because EtherNet adopts CSMA/CD mode, when the network load is large, the uncertainty of network transmission can not meet the real-time requirements of industrial control, so the traditional Ethernet technology is difficult to meet the real-time requirements of the control system requirements for accurate timing communication, and has been regarded as a “non-deterministic” network. However, the development of fast Ethernet and switched Ethernet technology brings a new opportunity to solve the non-deterministic problem of Ethernet, which makes this application possible.