Ethernet and especially Industrial Ethernet such as Profinet are popular technical terms in the production sector. Although similar, both have different features and benefits. This article explains Ethernet and Industrial Ethernet and shows the points in which the two differ.
The ISO/OSI reference model defines and describes the seven layers of communication between systems. (Picture: Profibus user organization)
Ethernet began with a single cable that allowed multiple devices to be connected to a network. Today, an Ethernet network can be expanded to include new devices as needed. Ethernet has now become the most widespread network technology in the world. An Ethernet shares the data streams into shorter parts or data frames, with each data packet containing special information, such as the source and destination address of the data. This data is necessary for the network to accept and send data as needed.
Common terms used in Ethernet technology include a “medium”, in current Ethernet technology a twisted pair or fibre optic cabling that connects Ethernet devices and thus provides a data path. A “Segment” is a single piece of media shared by multiple devices. A “node” is a collection of devices connected to a segment.
Ethernet allows computers to be connected over a network. Industrial Ethernet is Ethernet used in the industrial sector, which often requires more robust connectors and cables, but above all better determinism. (Source: Carlos Castilla – Adobe Stock)
Standard Ethernet can transfer data at speeds of 10 to 100 Mbit/s. Gigabit Ethernet is a term used in the IEEE 802.3 standard to describe Ethernet speeds of 1 Gbps. The term Gigabit Ethernet was initially used typically for backbone network transport and for high-performance or high-capacity servers. However, over time, Ethernet could also support desktop connections and personal computers. Not to be confused with Wi-Fi, Ethernet uses cables to connect computers and devices. Almost every reference to a network or local area connection means Ethernet.
What is Ethernet?
Developed in the 1970s, Ethernet is now standardized as IEEE 802.3 (Institute of Electrical and Electronics Engineers). Ethernet is a wired data transmission technology made up of hardware and software components that were originally intended for local data networks (LAN). In the OSI (Open System Interconnection) model, Ethernet defines both the physical layer and the data link layer of wired Ethernet media access control. The standard also describes the rules for the configuration of an Ethernet network and the interaction of the network elements with each other.
Ethernet allows computers to be connected over a network – without it, communication between devices would not be possible in today’s world. Ethernet is the global standard for a wired system for connecting multiple computers, devices, and machines over a common network within an organization so that all computers can communicate with each other.
In a bottling plant, the Industrial Ethernet can monitor the correct filling of the bottles. (Source: Analog Devices)
How does Industrial Ethernet work
Industrial Ethernet protocols such as Profinet and EtherCAT modify standard Ethernet by ensuring the correct sending and receiving of specific production data at the exact time required for a specific operation. For example, a bottling plant Send filling data over the network using Industrial Ethernet automation technology to guarantee bottles are filled on schedule. As soon as a bottle is full, the network sends a corresponding signal over the network.
Such a message is less important in an office environment. If a web page stops responding, the user simply clicks the refresh button. In a factory, however, a small problem could trigger a catastrophe – in a company, there is simply no time for someone to notice the error and manually press a button. However, the Industrial Ethernet automation network can detect errors in the filling process and automatically stop the process. Above all, this prevents wasted time, resources and money.
What is Industrial Ethernet?
Industrial Ethernet, the successor to the classic field-buses, is exactly what it sounds like: Ethernet, applied in the industrial sector, often requires more robust connectors and cables, but above all better determinism. Industrial Ethernet uses special Ethernet protocols for better determinism. Widespread Industrial Ethernet protocols are, for example, Profinet, Ethernet/IP, Ethercat, Modbus TCP, CC-Link IE, Sercos III and Powerlink. Industrial Ethernet enables data transmission rates from 10 MBit/s to 1 GBit/s, with 100 MBit/s being the most common speed in Industrial Ethernet networks.
Industrial Ethernet requires additional considerations compared to, for example, Ethernet systems for office use. Production systems in workshops are exposed to high temperatures, vibrations, moisture, dust and other sources of interference such as high EMC loads.
Production facilities in workshops are exposed to demanding environmental conditions – a fact that the network must also take into account. (Source: Analog Devices)
Other differences between Industrial Ethernet and Ethernet
Ethernet is used more in offices than in industrial environments. For office communications, Ethernet is designed for base-level usage, while Industrial Ethernet is multi-level and suitable for heavy-duty environments. Like field-buses, Industrial Ethernet can better handle disturbances in factory environments, better meet the requirements of factories and is therefore particularly suitable for use in harsh environments. In addition, Industrial Ethernet is able to react better to data collisions inside the factory floor.
Cables and connectors can also vary with Industrial Ethernet technology. For example, connectors for industrial environments do not have snap mechanisms because stronger locking mechanisms are required due to the harsher environment. Even sealed connectors are often used for high-performance applications unavoidable.
The cabling can also differ between commercial or Ethernet for office communication and Industrial Ethernet. Light-duty industrial cables can have a higher quality jacket than regular Ethernet cables. With heavy-duty cables, the jacket and metal used are of higher quality to make them more durable.
Industrial environments require the determinism of Industrial Ethernet
Determinism is an important criterion when defining industrial Ethernet systems and distinguishing them from standard Ethernet. Standard Ethernet is not deterministic on its own. However, industrial environments require determinism – there is a need to send and receive data packets at specific times. In addition, the network must be able to guarantee any delivery of data.
This is because a loss of data or a delay in data exchange between devices and the industrial environment can lead to disaster – such as a weak point in the production process. Real-time information transmission is often an important criterion for companies when selecting a suitable Ethernet solution that also takes into account the company-specific requirements.
What is the difference between Profinet and Ethernet?
What is the difference between Profinet and Ethernet? Can you give us a comparison between Profinet and Ethernet? The Profibus user organization or Profinet International, which also takes care of IO-Link, Omlox and Profinet, is often asked these questions. They are actually easy to answer, since Profinet and Ethernet technologies complement each other or, in other words, build on each other and not compete technologies are. Here is a comparison between Profinet and Ethernet.
First of all, a look at the ISO / OSI model, a seven-layer model that describes the abstraction layers of a communication system in general, helps. Every network communication can be divided into several layers. IEEE 802.3 defines the standards that makeup Ethernet. Ethernet resides at Layer 1 (Physical Layer) and Layer 2 (Data Link Layer) of the ISO/OSI model. Ethernet defines two transmission units: packet and frame. The frame contains information such as the MAC addresses of the sender and receiver, the VLAN tagging (Virtual LAN) and the QoS (Quality of Service). To put it more simply: Ethernet defines how a telegram frame is structured and transmitted over a line. The meaning of the bits and bytes in the data field of this frame
What is Profinet?
Profinet is an Industrial Ethernet standard. It is a communication protocol for data exchange between controllers and devices (IO devices). Controllers can be, for example, a PLC, a process control system or a PAC (programmable automation controller). Devices can be I/O units, vision systems, RFID readers, drives, process instruments, proxies or even other controllers. Profinet is on layer 7 of the ISO/OSI model because it is an application. It defines cyclic and acyclic communication between components, including diagnostics, functional safety, alarms and other related information.
In summary, this means: The structure of the data in a frame and the respective meaning is precisely defined across manufacturers. A user can easily access parameterization data, diagnostic data and, of course, input/output data and does not need to worry about putting them together in a telegram or even setting up monitoring mechanisms. In addition, defined startup sequences with corresponding state machines are specified so that the transitions and the status of the devices are clearly regulated.
Without such a specification, a user of an automation system would have to pull up these processes individually for each device according to the manual at a bit and byte level with the corresponding effort and potential for errors.
These are the differences between Profinet and Ethernet
All in all, it is difficult to make a comparison between Profinet and Ethernet as they are of different nature. Ethernet (Layer 1 and 2) defines the electrical signals within the cable, how the bus is accessed and how telegrams are sent and received on a LAN. Profinet, on the other hand, is an application (layer 7) based on standard Ethernet for layers 1 and 2.
In a Profinet network, the Ethernet cables that connect the Profinet components are what stand out. When users then continue to configure the network, they work with Profinet controllers and devices. With Profinet, a network configuration can be created and the data exchange between controllers and devices in an automation network can be defined.
What about Single Pair Ethernet?
In the future, two wires will bring Ethernet to every corner of the machine – including the power supply: Single Pair Ethernet (SPE). Here there are already first examples in practice. However, SPE has not become established on a broad front, simply because components are still missing and because there are still problems in some areas. In the future of automation, however, SPE is sure to be a crucial one Role-play.