Industrial Ethernet

6 Advantages of Single Pair Ethernet

Chen Zhang

Gear Up to Drive IIoT with Single Pair Ethernet–from the Sensor to the Cloud

Over the past 20 years, Ethernet has increasingly infiltrated the factory floor as the primary means of connecting automation systems and transmitting field data to the network. Now the industrial arena is experiencing yet another revolution with Industry 4.0 and IIoT by which real-time data from connected sensors and actuators are being monitored, shared and analyzed. This enables advancements like artificial intelligence, machine learning and digital twin technology that prevent downtime via predictive maintenance and optimize productivity via automated forecasting and inventory management.


As traditional distributed control systems are replaced by automation, only one physical layer technology is positioned to deliver significant cost reduction, space savings, greater coverage and enhanced performance. That technology is Single Pair Ethernet (SPE), and it is calling for immediate action by those developing the factories of the future.


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Why SPE, Why Now?

Industrial Ethernet protocols like Modbus TCP/IP, EtherCat, EtherNet/IP and Profinet have significantly improved communication at the routing and supervisory levels, but much of the device-to-device communication at the field/IO level has long relied on traditional Fieldbus protocols like Profibus, AS-Interface, Modbus, CANOpen, DeviceNet, CC-Link and IO-Link that typically require multiple segregated and proprietary cabling plants.


Traditional Fieldbus protocols have long been touted for their time-sensitive transfer and determinism to ensure that the right information is sent and received when and where it is needed, which is critical for communication in industrial control and automotive applications. However, the development of Time-Sensitive Networking (TSN) by the IEEE addresses these needs via time synchronization and deterministic communication over standard Ethernet.


With vast increases in the number of sensors and actuators at the field/IO level and the growing demand for more information, traditional Fieldbus protocols are quickly becoming the bottleneck within the automation environment, topping off at 10 to 12 Mbps with limited link lengths. As more links are integrated within automation systems and machinery, bulky Fieldbus cables take up too much space and come with costly and challenging installation (often in filled conduit).


With the introduction of SPE, together with TSN capability, the time is right for one standard end-to-end Ethernet network and entirely digitized communication. The end-user gains significant benefits from enabling massive amounts of sensors, actuators and I/O modules at the field level, feeding data from the field to programmable logic controllers (PLCs), manufacturing execution systems and on to the factory enterprise backbone to the cloud simultaneously in real-time.


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6 Advantages of Single Pair Ethernet

With one Ethernet network from the sensor to the cloud, SPE and TSN enable control over all networked components to drive the deployment of IIoT within the industrial environment. They also aim to reduce CapEx by 80% while delivering long-term operational savings through a variety of benefits.

  1. Compact, lighter cables with 50% less weight and footprint than traditional Fieldbus cables save space within robots and inside walls and floors, while enabling a more orderly, defined infrastructure and reducing power and temperature control requirements.

  2. Faster, easier installation drives material and labor costs down for new factory floor builds, allowing field devices, sensors and actuators to be easily integrated into the existing Ethernet environment with no additional gateways and interfaces.

  3. Potential for 10 times better range and device coverage with the ability to support 10Mbps to distances up to 1000 meters and 10 times the transmission performance with existing options for 1Gbps and multi-gigabit on the horizon.

  4. Bus topologies with no additional power lines via short multidrop link segments combined with Power over Data Lines (PoDL).

  5. Simple, cost-effective passive line distribution with the potential for cable sharing where common twisted-pair cable enables four SPE channels in one cable.

  6. Known standards-based cable and connectivity with interchangeable plug-in M8 and M12 connector interfaces that meet the established M2I2C2E2/M3I3C3E3

Ramping Up Fast

Single Pair Ethernet was driven primarily by the automotive industry due to the need for smaller, lighter, high-bandwidth cables used in vehicle harnessing systems. Early SPE standards like 1000BASE-T1 (2015 IEEE 802.3bw) and 1000BASE-T1 (2016 IEEE 802.3bu) included TSN that offered low deterministic latency and PoDL for remote powering of devices.


The industrial and process automation world took note of these SPE accomplishments, and the IEEE P802.3cg 10Mbps Single-Pair Ethernet Task Force group was formed. The goal was to develop short-reach 10BASE-T1S supporting 10 Mbps to at least 15 meters and long-reach 10BASE-T1L to at least 1000 meters, which are an attractive alternative to traditional Fieldbus protocols and ideal for connecting low-speed IIoT and IoT devices. Now multi-gig SPE (2.5, 5 and 10Gbps) is under development by the IEEE 802.3ch task force and is expected within the next few years.


The market demand, combined with the development of the standards, means a very bright future for SPE that will lead to industrial Ethernet more than outpacing traditional Fieldbus communications over the next five years. Belden projects a high ramp-up rate for SPE of 2 to 3 million installation nodes in the first five years, followed by exponential growth.


Time to Act

The rise of smart, connected devices brought on by Industry 4.0 and IIoT, supported by an SPE physical layer, will deliver significant cost reduction, space savings, greater coverage and enhanced performance.


Key stakeholders across the entire value chain – from the developers of the sensors and actuators to the innovators of automation and robotics and those looking to build the next smart factory – need an industry-leading partner with the engineering, product and application expertise to develop a complete end-to-end SPE solution. That partner is Belden.


When it comes to signal transmissions, Belden is the number one solutions provider. In conjunction with developing the most advanced cable on the market, we are investing in developing the complementary SPE infrastructure.


Whether you’re involved in developing the technologies that will collect, analyze and process real-time field data, or designing the smart robotics, machines and automation equipment that will respond to that data and optimize production, Belden wants to know your specific challenges and goal to help push you ahead of the competition. Together, we can form a partner ecosystem to drive IIoT with SPE – from the sensor to the cloud.