Single Pair Ethernet
At a glance
Single Pair Ethernet (SPE) is a special Ethernet technology that uses only one pair of wires for data transmission - hence the name Single Pair. For comparison: conventional Ethernet infrastructure uses four wire pairs. The technology is specifically aimed at space-saving, efficient networking of devices and components in industrial environments, e.g. in plant automation or vehicle construction. In IIoT (Industrial Internet of Things) it is particularly important that data transmission between the devices and sensors involved functions smoothly and in real time. The aim here is to enable machines to carry out as many tasks and decisions as possible independently. This only works if the devices involved have all the necessary information from their environment (e.g. measurement data from sensors) available at the right time.
Advantages of Single Pair Ethernet
SPE has the potential to advance the digitalization and automation of processes in industry. The technology offers standardized and thus easier to implement connectors that enable the use of IP-based communication even in the smallest devices.
An internationally standardized interface (IEC 63171-6) exists for SPE. This allows hardware manufacturers to offer a standardized interface for their devices that is guaranteed to be compatible with other devices that use this standard. Companies can use their SPE-enabled devices interchangeably and no longer have to worry about a proprietary cabling solution when planning. It also makes it easier to build complex infrastructures.
Space-saving plug connection
The "T1 Industrial style" type has established itself as the standard for plugs and sockets of SPE-compatible devices. This type is characterized by its slim form factor: The plugs and sockets have deliberately been designed to be as slim and light as possible so that they can be used sensibly even with the smallest devices such as sensors and do not take up too much space or weight on an otherwise very small device. This not only saves costs and material, but also allows the construction of even smaller IIoT components.
High transmission rates and faster communication at field level
The most common alternative so far is systems based on analog fieldbus technology. Here, the sensors and actuators are connected to a control unit (gateway), which controls the communication between the devices on the field level and partly also serves as an interface to all higher levels. This system brings its own protocols with it and does not offer the transmission speeds that are desirable in a modern real-time system. SPE brings IP-based communication directly to the devices at the field level, thus eliminating the need for specialized gateways: All devices, from the smallest sensor to the data center, use the same protocol, i.e. speak the same language. SPE also enables transmission speeds of up to 1 Gbit/s via Ethernet for the smallest components such as sensors or actuators. Measured values can thus be divided in real time and commands for actions can be executed immediately.