Benefits of Single Pair Ethernet in the Automotive Industry

In this article, I will introduce you to what Single Pair Ethernet is, its benefits, and how it can be applied effectively in manufacturing automation systems.

Ethernet’s role in industrial automation

Let's start with a brief history of Ethernet in industrial automation. Ethernet has become the backbone of industrial communication networks, thanks to its robustness and flexibility.

The IEEE 802.3 family of standards has continuously evolved, providing reliable solutions for various applications.

What is Single Pair Ethernet

Now, what exactly is Single Pair Ethernet, often called SPE?  SPE is an Ethernet technology that uses a single pair of twisted copper wires to transmit data.

By contrast, traditional Ethernet typically uses four pairs of wires. SPE is defined by several IEEE 802.3 standards.

The key standards for Single Pair Ethernet include:

• IEEE 802.3cg for 10Mb communications. This standard defines two protocols: 10BASE-T1S and 10BASE-T1L.
• IEEE 802.3bw for 100Mb communications. This standard defines the 100BASE-T1 protocol.
• IEEE 802.3bp for 1Gb communications using the 1000BASE-T1 protocol.

These standards ensure compatibility and interoperability across various devices and applications.

Single Pair Ethernet: Properties and benefits

SPE can be implemented in various ways, such as IEEE 802.3cg's 10BASE-T1S and 10BASE-T1L, each serving different needs.

10BASE-T1S is designed for short-range communication of up to 25 meters, while 10BASE-T1L is suitable for long-range communication of up to 1,000 meters.

Cables and connectors

SPE uses lighter cables and supports multiple topologies, including point-to-point and multidrop.

The connectors are standards-based, ensuring compatibility across different systems. Another significant advantage is Power over Data Lines, or PoDL, which allows power and data to be transmitted over the same pair of wires.

Additionally, hybrid cabling solutions can combine power and data with other signals, enhancing flexibility.

SPE benefits to automation engineers

So, what does this mean for automation engineers? SPE offers several benefits:

• Ease of design and installation due to its simpler cabling.
• It can replace other Fieldbuses, providing a unified communication protocol.
• The standards-based implementation ensures compatibility and futureproofing.
• Faster data transmissions and higher bandwidths improve system performance.
• SPE is also suitable for use in hazardous areas, enhancing safety and reliability.

Single Pair Ethernet: A case study

Single Pair Ethernet (SPE) has naturally evolved in the automotive industry due to the need for high data communication rates, compact installations, and advanced capabilities like Bluetooth and Wi-Fi.

The automotive application of SPE utilizes the 10BASE-T1S network, defined by IEEE 802.3cg, which provides 10 Mbps communication speed.

This network connects various sensors and actuators to various on-board control modules, ensuring a smooth and efficient driving experience.

In modern vehicles, sensors such as voltage sensors, oil and tire pressure sensors, vehicle proximity sensors, and cameras are integral for monitoring and control.

Actuators, including solenoids, wiper motors, smart suspension elements, and seat positioning servos, interact with these sensors through sophisticated CPU modules.

The ECU (Electronic Control Unit), often referred to as the car’s onboard supercomputer, plays a crucial role by collecting and storing data related to vehicle performance, such as speed, fuel efficiency, and engine diagnostics.

Today's cars can have 30 to 50 sensors for engine monitoring alone, with another 20 to 40 sensors for ancillary functions.

As the number of sensors and actuators in vehicles continues to grow, engineers are developing faster networks like the IEEE 802.3bw standard, which supports 100 Mbps communication. This ensures the efficient handling of increased data traffic.

The 10BASE-T1S network is particularly suitable for automotive applications due to its lightweight cabling that supports both power and data transmission over a single pair of wires.

It provides reliable communication over a network loop of up to 25 meters, with drops to individual nodes of 2 meters or less. This network structure eliminates the need for network switch hardware, reducing complexity and cost.

SPE enables efficient in-vehicle communication, linking various ECUs responsible for engine management, transmission control, and safety systems.

It is especially critical in electric vehicles, connecting battery management systems, power distribution units, and charging systems.

SPE also enhances automotive sensor networks, supporting real-time communication required for advanced driver assistance systems (ADAS), such as adaptive cruise control, lane-keeping assistance, and collision avoidance.

Moreover, SPE simplifies troubleshooting and maintenance by integrating into on-board diagnostic systems, allowing for efficient vehicle diagnostics and quick issue resolution, while also enabling the rapid collection of more data from sensors.

For example, tire pressures in one tire trending downward may indicate a slow leak that would allow a repair before serious deflation on a highway. This technology helps ensure long-term reliability and performance, making SPE a critical asset in modern automotive applications.

Conclusion

In this article, I introduced single-pair Ethernet ( SPE), its benefits, and its applications in industrial automation systems. SPE, defined by IEEE 802.3 standards, uses only a single pair of wires for communications, unlike traditional Ethernet.

SPE offers ease of design, higher bandwidth, and suitability for hazardous areas.

The case study I presented from the automotive industry highlights SPE's role in connecting sensors and actuators to an automobile’s many control modules, enabling efficient communication, especially in electric vehicles.

SPE simplifies diagnostics and maintenance, ensuring long-term reliability and performance.

For in-depth learning about Single Pair Ethernet, be sure to check out our courses Single Pair Ethernet Fundamentals and Single Pair Ethernet:  Real-World Examples on Realpars.com.

These courses have been developed in partnership with TE Connectivity. At the end of each course, you will receive a certificate of completion from TE Connectivity.

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