Technology
Single Pair Ethernet: two wires into the future
SOURCE: TERZ
Single-pair Ethernet (SPE) is a megatrend in automation technology. But it also offers the potential for use with already installed bus cables to modernize and upgrade existing plants and machines by integrating functions like condition monitoring and predictive maintenance.
Single Pair Ethernet Evaluation Board with RJ45 jacks. ETHERNET NETWORKING OF AUTOMATION systems with all its advantages has long been established in factory automation, robotics and also in commercial vehicles. Single-pair Ethernet now adds further decisive advantages that significantly reduce investment costs, installation effort, space requirements and weight. Completely digital IP-based and transparent network communications from the sensor to the cloud is now possible. But is it really that simple? Single-pair Ethernet (SPE) is one of the trends in automation technology in the coming years. The advantages of using a simple twisted-pair cable as the communication medium offer considerable potential for cost reduction and space savings. Also the possibility to continue using already installed bus cables offers the chance to modernize and upgrade existing plant facilities and machines to integrate functions like condition monitoring and predictive maintenance.
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The standard
Originally developed for the automotive sector to bring Ethernet into vehicles as an on-board network, SPE or T1 Ethernet is now considered the revolution for networking sensors and actuators in industrial and building automation. In addition to reducing cabling, SPE technology offers the ability to build a fully IP-based transparent communication link from the sensor to the cloud. Proprietary bus systems and transmission technologies and the gateways they require are thus obsolete in future IIoT 4.0 applications. Thanks to full compatibility with classic Ethernet at the protocol level, hardly anything changes for the user except for the reduced cabling. The IEEE specifies different single pair Ethernet variants. For the user, these differ mainly in the available data transmission rate and the maximum cable length. A decisive advantage that is often listed is that an unshielded 1-pair twisted pair cable is sufficient for data transmission, with which
data can be transmitted over a distance of at least 15m at 100 Mbit/s (IEEE 802.3bw 100Base-T1). A simple cable offers the great advantages that it is cheaper and can be laid easily due to the smaller diameter and bending radius.
Interference on the network
In industrial applications, however, interference factors naturally occur that can negatively affect the network and communication and have a significant impact on reliability, transmission quality and security. Especially at the connection points where connectors, cables and devices meet, the risk of interference from vibrations, dirt, moisture as well as external electromagnetic influences is high. It is precisely at this point that the applications in industry differ from those in the automotive sector. While the use of SPE as an on-board network is based on a clearly defined encapsulated system in which all components are matched to one another and
in d u s t r ial et h er ne t b o o k
11.2021
