Ethernet refers to a cable-based data transmission method consisting of hardware and software components. Industrial Ethernet refers to all efforts to use the Ethernet standard for networking devices in automation technology and Industry 4.0. The international IEE 802.xx series of standards applies to these efforts. In this context, it is also referred to as real-time Ethernet.
Ethernet or Industrial Ethernet is a process that enables the exchange of data between devices connected to a wired network. The exchange takes place in the form of so-called data packets. The Ethernet process describes both the hardware and the software for local data networks and is therefore also called LAN technology.
Industrial Ethernet – as a further development of the conventional Ethernet – aims to extend these possibilities to devices that serve industrial manufacturing and control of production processes. The real-time Ethernet integrates the control and monitoring devices into the existing LAN network.
Modern Ethernet technology includes a so-called "medium", which consists of a twisted pair cable or fiber optic cabling. The medium connects the Ethernet devices and provides a data path. The so-called "segment" refers to a medium that is shared by several devices. A group of devices connected to the segment is called a "node".
Standard Ethernet transmits data at a speed of ten to 100 Mbps. So-called Gigabit Ethernet (according to standard IEEE 802.3 of the Institute of Electrical and Electronics Engineers), on the other hand, achieves speeds of one GBit/s. Gigabit Ethernet was typically used initially for backbone network transports and for high-performance servers. Today, however, Gigabit Ethernet also supports PCs and desktop connections. Note: Ethernet should not be confused with Wi-Fi, because unlike the latter, it uses cables to connect devices. So when we talk about a network or LAN connection, we almost always mean Ethernet.
Industrial communication networks can be divided into three communication levels – control, supervisory and sensor. The goal of Industrial Ethernet is to provide a unified communication system between these systems, enabling real-time communication. Losses due to system and transmission errors can thus be avoided.
For the production sector, both Ethernet, developed in the 1970s, and the more recent Industrial Ethernet, such as Profinet, play an important role. Both processes are similar, but also have different features and advantages.
Ethernet was originally intended for local data networks (LAN) and enables the interconnection of several computers, devices and machines via a network. Only thanks to Ethernet can computers and devices communicate with each other. The idea of Industrial Ethernet is a further development of Ethernet, which has been the subject of intensive research for more than ten years.
The aim was to use Ethernet in conjunction with TCP/IP protocols to create a uniform real-time protocol for the communication of automation processes. Due to its susceptibility to collisions, the original Ethernet with a transmission speed of up to ten Mbit/s was not suitable for these purposes. By using switches, prioritizing messages and full-duplex transmission, it was initially possible to develop the so-called "Fast Ethernet" and transmit messages without collisions. The speed here is 100 Mbit/s.
So while Ethernet is designed for use at the basic level and is more commonly used in office environments, Industrial Ethernet is suitable for multiple levels and thus for environments with high requirements. Like fieldbus systems, Industrial Ethernet is more likely to meet the requirements of factory environments, handles interference better, and is therefore particularly suitable for use in harsh environments. In addition, Industrial Ethernet responds better in the event of a data collision within the factory floor.
Industrial Ethernet is based on the international cabling standards. The approximately 20 protocols that exist for Industrial Ethernet are based on the IEEE 802.3 standard. The conventional fieldbus protocols are transmitted via Ethernet using tunneling or encapsulation. The major advantages of Industrial Ethernet are the simple portability, the consistency of the communication systems and the direct adoption of the application layer of the fieldbus.
Ethernet communication is always based on protocols that belong to the so-called "Internet Protocol Suite". This protocol family is usually referred to as TCP/IP in reference to its best-known protocols Transmission Control Protocol (TCP) and Internet Protocol (IP). The same protocols also form the basis for network communication on the Internet. Thus, the protocol determines the address by means of which the network transmits the data packet from the sender to the receiver. Even without a direct connection, the protocol can initiate the transmission of packets within the network. If the data packet consists of datagrams, they can even be split and reassembled. Furthermore, data connections with different maximum transmission units can be used.
For industrial applications and in automation technology, the CIP protocol is used, which enables cyclic and time-critical data transmission. Thanks to the interoperable CIP networks, it is possible, for example, for a DeviceNet to work with an EtherNet/IP.
Industrial Ethernet scores with exactly the determinism that industrial contexts need. But what is meant here by determinism? It is an important criterion for differentiating Industrial Ethernet systems from standard Ethernet. In most cases, the selection of an Ethernet solution or an Ethernet protocol results from the type of control of a plant or machine. This simplifies the integration into the respective control system.
For example, standard Ethernet is not deterministic, but in industrial environments the network must be able to send and receive data packets at specific times and guarantee any transfer of data between devices and the industrial environment. The reason: a loss of data or a delay in the exchange of data can have serious consequences – for example, a weak point in the production process, or the late detection of defective industrial spare parts.
For companies, real-time data transmission therefore often plays an important role in the selection of the appropriate Ethernet solution. After all, this must take company-specific requirements into account.
Further considerations as to which Ethernet products are suitable for the respective application are the following in production plants and factory halls:
To be able to withstand the respective conditions on site, the different Industrial Ethernet solutions are equipped with one or more of the following features:
In which areas does Industrial Ethernet need to be used and in which not? Industrial communication networks are usually divided into control, monitoring and sensor levels. The communication requirements between the connected devices differ depending on the level and the area of application. For example, the control level is usually only found in large, standardized and highly automated plants, for example in vehicle construction or process technology. Here, the need for communication between the automation systems is usually not too time-critical and standard Ethernet is used in combination with various IT protocols.
The control and sensor levels, on the other hand, are found in all automated applications. Here, the real-time properties of the respective communication system play an increasingly important role.
Industrial Ethernet is used where normal network methods reach their limits. It is therefore used, for example, in environments where extreme temperatures prevail. For example, very few electronic devices can function at temperatures below -10 and above 50 degrees Celsius.
The advantages of Industrial Ethernet over fieldbuses in summary:
Ethernet technology allows computers, devices and machines to connect and communicate over a network. Industrial Ethernet is a further development of this original Ethernet, which is used in the industrial sector and requires a better determinism and often also more robust connectors and cables.
Industrial Ethernet is a successor to the classic fieldbuses and uses special protocols to achieve better determinism. Special protocols for Industrial Ethernet are for example Profinet, Ethernet/IP, Modbus TCP, Ethercat, CC Link IE, Powerlink and Sercos III. Industrial Ethernet achieves data transmission speeds of 10 MBit/s to 1 GBit/s. Thereby, 100 MBit/s represents the most widespread speed in Industrial Ethernet networks.
In the meantime, Industrial Ethernet is a frequently used, but still young technology, which is constantly being further developed. Intensively researched topics are still the improvement of performance and clock synchronism as well as the integration of security protocols and energy management.
