What does single pair Ethernet (SPE) mean and how is it different from conventional Ethernet?
Single-pair Ethernet cables are copper cables that contain just one twisted pair of wires (single pair) for data transmission, for example in industrial applications. However, the conventional Ethernet cables from the LAN sector or industrial Ethernet cables use 2 or 4 conductor pairs depending on the transmission rate. Single pair Ethernet technology is the lean, lightweight and material-saving Ethernet development for many current and future applications.
Why was SPE developed?
Industry 4.0 and the Industrial Internet of Things (IIoT) require a uniform network infrastructure across all levels and systems, as well as data transmission in real time.
The classic Ethernet, which already connects all upper layers in the automation pyramid, is often unsuitable for connecting the lowest field level because the cables are difficult to connect and are oversized. Therefore, conventional Fieldbuses currently have advantages over the Ethernet standard in these areas. They are the ones that regulate the exchange of information between sensors and actuators with the control level (PLC). These BUS systems are now to be replaced by SPE systems and corresponding SPE cables as soon as possible.
The advantages of single-pair Ethernet at a glance:
The advantages of single-pair Ethernet at a glance:
- Replacing Fieldbuses with future-proof single-pair Ethernet systems.
- Standardization of technology in IP-based networks, from sensor to ERP or into the cloud to the benefit of smart factories.
- Smaller cables save material cost, and reduce weight and space required. Space plays an essential role in the networking of sensors and actuators in particular.
- Single-paired cable design enables significantly quicker and easier on-site installation and reduces the potential for errors during assembly.
- Cost-effectiveness due to the elimination of additional gateways that were previously used to connect the Fieldbuses to the higher-level standard Ethernet. Connecting the field level with SPE does not require translators.
- SPE enables terminal devices to be supplied with up to 50 W via the data cable using PoDL (Power over Data Line). This is comparable to PoE, which has already proved its worth with today's Ethernet.
- The open cabling standard with compatible cabling components is suitable for universal use in the entire automation industry.
What's next with SPE?
To ensure that the new technology arrives quickly in factories, standardized communication protocols had to be created. This has been done in the meantime. The protocol standards according to IEEE 802.3 define the technical framework conditions for single-pair Ethernet transmissions in industrial applications; the industrial connector face “T1 Industrial Style” is standardized in IEC 63171-6.
The working group IEEE 802.3 has defined standards for different SPE applications.
| SPE standard | Bit rate | Cable length point to point | Cable length point to point |
|---|---|---|---|
| shielded | unshielded | ||
| IEEE 802.3ch | 2.5/5/10 Gbit/s | 15m (49.22 ft) | - |
| IEEE 802.3bp | 1 Gibt/s | 40 m (131.24 ft) | 15 m (49.22 ft) |
| IEEE 802.3bw | 100 Mbit/s | 40 m (131.24 ft) | 15 m (49.22 ft) |
| IEEE 802.3cg | 10 Mbit/s | 1000 m (3281 ft) and more | - |
LAPP is a member of the SPE Industrial Partner Network, a consortium of well-known companies that want to help SPE technology break through.
The network of partners aims to create an integrated SPE infrastructure. The innovative technology should not only guarantee reliable data transmissions, but also provide standardized interfaces and system components. The foundation for this has already been laid by defining standards and working closely with international standards committees.