Single-pair Ethernet expands beyond automotive applications

Single-pair Ethernet (SPE), rated for rugged and harsh environments, is lightweight and more cost effective than four- or eight-wire Ethernet and can enable the Industrial Internet of Things (IIoT). See industrial communications speed vs. distance table.

By Mark T. Hoske December 28, 2021
Courtesy: Control Engineering

 

Learning Objectives

  • Learn about single-pair Ethernet (SPE) over twisted pair, standards, applications.
  • Review industrial communications protocols: Distance versus speed.
  • Examine recent SPE products, such as semiconductors, connectors, transformers, filters.

Single-pair Ethernet (SPE) is rated for rugged and harsh environments, is lightweight and more cost effective for uses in devices on the edge of industrial networks (compared to four- or eight-wire Ethernet) and can serve as a backbone and enabler for the Industrial Internet of Things (IIoT), according to information from the SPE Symposium 2021.

SPE, used in on-automobile applications for 10 years, is gaining attention in other applications. The online 90-minute October 2021 symposium, “Road to Mass Single Pair Ethernet Adoption,” included experts from Belden, Harting Americas, Texas Instruments and Wurth Elektronik. Mouser provides a page for SPE information from Analog Devices, Harting and Wurth Elektronik.

According to Mouser, growth of smart factories and the IIoT has led to the need for robust connectivity on the factory floor. Ethernet is the leading architecture for large-scale industrial connectivity, serving as the primary means of connecting automated systems to the network. SPE technology delivers high-performance data and power transmission through a single-wire pair to field-level actuator devices and sensors.

SPE Symposium experts were:

  • David Camp II, senior product engineer, Belden
  • Arnold Tchiegne, senior product and application manager, Harting
  • McKenzie Reed, technology manager – standards development, Harting
  • Nazario Biala, industry segment manager, Harting
  • Genevieve Vansteeg, marketing manager, Texas Instruments
  • Martin Leihenseder, senior specialist signal and communications, Wurth Elektronik.

Ethernet over twisted pair, standards, applications

Reed offered background, explaining SPE as a IEEE 802.3 project, fast Ethernet using twisted pair wire to transmit and receive at 10 mbit/sec (1000m distance), 100 mbit/sec and 1 gbit/sec (40m) and 10 gbit/sec (15m) for signal with power.

Standardization is provided by TIA, IEC 63171-6, as well as IEEE 802.3cg.

Because of lower costs associated with SPE, many applications will be getting cost-effective Ethernet for the first time, including those using cloud, supervisory, control and programmable logic controllers, and filed devices. Specific SPE applications, Reed said, including remotely controlled or autonomous aerial vehicles, autonomous vehicles, industrial and process automation and mobile robotics.

Field devices typically have not been connected to Ethernet because of cost, but SPE will change that, Reed suggested.

Interest is growing with number of participants in the SPE Industrial Partner Network, which began with seven in 2019 to about 50 members now, Reed said.

Reasons for the growth, said Camp, include demand for sensors-to-cloud connections, increased Ethernet distances, continued need for automation, Big Data, artificial intelligence (AI) and convergence of information technology and operational technology (IT/OT). Camp said that providing greater access to sensors and “eliminating legacy protocol translations” are pushing more market opportunities, include industrial automation in discrete and process verticals, robotics, mass transit and smart buildings.

SPE Symposium 2021 panelists were Genevieve Vansteeg, marketing manager, Texas Instruments; McKenzie Reed, technology manager - standards development, Harting; David Camp II, senior product engineer, Belden; Arnold Tchiegne, senior product and application manager, Harting; Martin Leihenseder, senior specialist signal and communications, Wurth Elektronik; and Nazario Biala, industry segment manager, Harting. Courtesy: Control Engineering

SPE Symposium 2021 panelists were Genevieve Vansteeg, marketing manager, Texas Instruments; McKenzie Reed, technology manager – standards development, Harting; David Camp II, senior product engineer, Belden; Arnold Tchiegne, senior product and application manager, Harting; Martin Leihenseder, senior specialist signal and communications, Wurth Elektronik; and Nazario Biala, industry segment manager, Harting. Courtesy: Control Engineering

Ethernet data: Better, faster, farther

Leihenseder mentioned the need for filtering for 10BASE-T1L networks (another name for IEEE 802.3cg) in many applications, to ensure signal quality. Performance can improve with the addition of power over data line (PoDL) and single-power power over Ethernet, 10BASE-T1L + PoDL (SPOE), which can enable data and power for 1 km distance, Leihenseder said.

Vansteeg said industrial network designers need to move data faster and farther to meet requirements of field devices. Using SPE has the added advantage of being able to incorporate other Ethernet protocols in use, allowing expansion while avoiding the need to rip and replace existing communications or adding complexity with gateways, she said. Vansteeg provided the following table showing some common industrial communications with distances and data rates and how they compare with IEEE 802.3cg (SPE, 10BASE-T1L).

Table: Industrial communications: Distance vs. speed

Courtesy: Texas Instruments, SPE Symposium 2021

Courtesy: Texas Instruments, SPE Symposium 2021

Using SPE extends reach and bandwidth while using existing infrastructure and implementing one network, from IT to OT. In smart buildings, if it’s a 10-year-old building, for instance, no one wants to rip and reinstall to meet expanding networking needs. SPE allows a gradual transition through expansions.

Vansteeg said single pair power over Ethernet (SPOE) reduces cost of ownership and provides Ethernet connectivity in intrinsically safe systems. If power requirements exceed the specification, power can be run separately. But for many applications, Vansteeg said, there’s no need to increase the amount of copper by running a separate power cable. SPE cable diagnostics increase reliability, she added.

Wide SPE use in automotive, SPE products drive expansion

Biala and Tchiegne joined prior speakers for a panel discussion that began by reviewing the technology adoption curve, placing SPE in the first group of innovators, as SPE use is just beginning. Other groups to follow with SPE adoption include visionaries, pragmatists and conservatives. For now, SPE use is scratching the surface, they suggested, even though it’s been in the automotive industry for 10 years to help with increased onboard communication needs resulting from cameras and entertainment. For more industrial automation users to get excited, more SPE-enabled products are needed, they suggested. More products are being developed.

SPE products: Chips, connectors, transformers, filters

Products for SPE include the following, highlighted in conjunction with the symposium.

Two flexible Industrial Ethernet semiconductor options from Analog Devices are ADIN1110 MAC PHY and ADIN1100 PHY. The ADIN1110 MAC PHY enables the industry’s lowest power systems, which simplifies retrofitting for Ethernet in field sensors or actuators and enables interfacing via SPI interface to any microprocessor. The ADIN1100 is said to be a robust, low-power Ethernet PHY, compliant with the IEEE 802.3cg Ethernet standard for 10 Mbits per second (Mbps) connectivity over 1.7 km of single-twisted pair cable. The ADIN1100 PHY provides standard Ethernet interfaces and supports use in more complex designs, making it a reliable option for process control, factory automation, and building automation applications.

Harting T1 industrial SPE products (connectors, cables and related tools) feature a highly optimized high-frequency design, as well as impressive mechanical robustness, making them an ideal choice for industrial applications including robotics, transportation, machinery, and agricultural equipment. Harting’s T1 industrial SPE products offer barrier-free connections by using end-to-end IP-based communications up to the field level.

Würth Elektronik Single Pair Ethernet products (Single Pair Ethernet Signal Transformers, WE-TVS High-Performance TVS Diodes, WE-CNSW High Frequency Common Mode Line Filters and Mid- and High-Voltage MLCCs) have thin cable diameters and a compact design, helping to reduce costs for a variety of applications. SPE products from Würth Elektronik can save up to 75% of printed circuit board (PCB) space, offering an appealing solution for DC-DC converters, USB 3.0, USB 2.0, HDMI, and LVDS applications. SPE products offer isolation in accordance with the IEC 62368-1 standard.

Mark T. Hoske is content manager, Control Engineering, CFE Media and Technology, mhoske@cfemedia.com.

KEYWORDS: Single-pair Ethernet (SPE), SPE applications, SPE specifications, SPE products

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Mark T. Hoske
Author Bio: Mark Hoske has been Control Engineering editor/content manager since 1994 and in a leadership role since 1999, covering all major areas: control systems, networking and information systems, control equipment and energy, and system integration, everything that comprises or facilitates the control loop. He has been writing about technology since 1987, writing professionally since 1982, and has a Bachelor of Science in Journalism degree from UW-Madison.