Industrial Communication Guide

4.2. INTRODUCTION TO INDUSTRIAL ETHERNET

connectivity. Full duplex is the capability of a component to re- ceive and send messages at the same time.

Distinction between Industrial Ethernet and standard / office Ethernet In contrast to use in the office environment, the following require- ments apply to Industrial Ethernet: • Environment requirement: The network components (cable, plug, switches) must have a higher protection class so as to be resilient to dust, splash wa- ter, lubricants and acid. Increased electromagnetic interferen- ce resistance and an extended temperature range are also key aspects. Vibrations caused by machines have to be taken into account, too. This requires the use of suitable cables (e.g. sheath resilience) and robust plugs. • Network requirements: While star topology has mainly become established in the office environment, line topology (daisy-chaining of devices) tends to be used in industry. In order to ensure a high level of fail safety, the network components have to be very reliable and precau- tions also have to be taken in the network itself (ring closures, redundancy concepts). Since the network has to be determinis- tic and as fail-safe as possible, “controlled” communication is required in the network. Most Industrial Ethernet systems were developed based on FAST Ethernet (100 Mbit/s) with full duplex

Categories of Industrial Ethernet technologies The various Industrial Ethernet systems can be subdivided into ca- tegories based on their technology type. The criterion here is the way in which they achieve real-time capability and determinism in Ethernet communication: 1. Standard IP communication In this case, IP-based communication takes place as in regular office communication. Components are addressed using their IP address. This makes communication beyond network limits very simple, as well as integration in company networks. The draw- back is that it is not possible to achieve the classic real-time pro- perties familiar from the fieldbus area. Here, average latencies of 100ms are possible. Typical representatives are EtherNet/IP and Modbus-TCP.

58