Modicon Quantum Automation Platform Page 8-14 Appendices and services

8/14 Presentation Technical information Ethernet network Infrastructure Presentation The ConneXium Industrial Ethernet Offer is comprised of a complete family of products and tools required to build the infrastructure of an Industrial Ethernet network. In the following pages, information for the proper design of a network and the selections of its components is offered. Office Ethernet versus Industrial Ethernet There are three main areas of differentiation between Ethernet applications in an office environment and Ethernet applications in an Industrial environment, they are: b Environment b Layout (not physical layer specification) b Performance Contrary to the office environment and even though ISO/IEC is working on it, there are not yet clearly defined specifications for Ethernet devices targeted to Industrial applications. The specifications of what it is called Industrial Ethernet are defined by different agencies or entities based upon its nature and based upon what the automation market has traditionally used. The environmental specifications of Industrial Ethernet devices are today defined by the traditional agencies that define the environmental specifications for standard industrial devices (UL, CSA, e , ...). The IEEE 802.3 defines the physical layer specifications of the Ethernet network (types of connectors, distance between devices, number of devices, ...) while the 11801 (similarly to the TIAEIA 568B, and CENELEC EN 50173) provide installers the layout guidelines. The performance specifications are actually being worked on by ISO/IEC. Ethernet 802.3 principles The Ethernet 802.3 Link Layer is based on a collision detection mechanism (CSMA CD): every node whose information has collided on the network realizes the collision and re-sends the information. The process of re-sending information causes delays in its propagation and could affect the application. A collision domain is a group of Ethernet end devices interconnected by hubs or repeaters (devices that receive information and send it out to all their other ports, no matter where the destination device is connected): it means that all devices will be affected by collisions. With the availability of full duplex switches (devices that receive information and send it out just through the port to which the destination device is connected) the collision domains have disappeared. Therefore, for industrial automation applications it is strongly recommended to use in every case full duplex switches to interconnect devices. In this way the collision domains will be eliminated completely. 2 1 3 4 5 6 7 8 9 10 2 1 3 4 5 6 7 8 9 10

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