What actually is ... Ethernet APL?
5/6/2024 Automation & digitalization Article

What actually is ... Ethernet APL?

The dead live longer. This also applies to the communication of measured values and device information in industrial systems: despite fieldbuses such as Profibus or Foundation Fieldbus, the 4 to 20 milliamp signal has been the undisputed standard since the 1970s. This is now set to change with Ethernet APL technology.

Control cabinet in a process plant with Ethernet APL connections and cables Ethernet-APL is now ready for use and is set to help the digitalization of process plants achieve a breakthrough.
The protagonists are talking about a revolution: Ethernet Advanced Physical Layer, or Ethernet-APL for short, will not only simplify process automation in the future, but also help digitalization at the sensor-actuator level (field level) to achieve a breakthrough. And this is how it works: Ethernet-APL adds special features to the enormously widespread Ethernet technology known from the office IT world, enabling it to withstand the harsh conditions of the process industry.
Network topology with Ethernet APL communication Typical network topology of an Ethernet APL application.

How does Ethernet-APL work?

Like the 4..20 mA signal, the technology makes it possible to send data and power simultaneously via simple two-wire lines (also known as "single-pair Ethernet", SPE), but now at turbo speed: the new physical layer achieves transmission rates of up to 10 Mbit/s over distances of up to 1,000 meters. This may not sound like much compared to Internet connections, but it is an enormous amount when it comes to applications in process plants. With the ability to supply devices with an electrical power of up to 92 watts, Ethernet-APL is a robust and efficient solution for industrial measurement technology that can significantly simplify installation in large systems compared to previous communication solutions - more power at significantly lower costs.

Parallel communication: multiple applications at the same time

In modern industry, it is normal for multiple systems to access the same network infrastructure at the same time - like when several family members stream videos and take part in video conferences at the same time. Ethernet-APL enables exactly that: smooth and simultaneous use by different applications. Whether it's real-time control protocols or retrieving diagnostic data - everything runs in parallel, without delays or conflicts.

What are the advantages of Ethernet-AP?

  • Robustness: Ethernet-APL was specially developed for use in demanding industrial environments and offers a high level of robustness against electromagnetic interference, vibrations and temperature fluctuations.
  • Long distances: Compared to conventional Ethernet cabling, Ethernet-APL enables transmission over longer distances, which increases flexibility in the location of devices.
  • Real-time communication: Ethernet-APL supports real-time communication, which is crucial for many industrial applications, especially in automation technology. This enables precise control and monitoring of processes. Compared to analog communication, Ethernet-APL allows access to device information for diagnostics and status monitoring. Compared to fieldbus systems such as Foundation Fieldbus or Profibus PA, the significantly higher bandwidth enables a high transmission speed.
  • Interoperability: During the development of Ethernet-APL, particular emphasis was placed on ensuring that devices and systems from different manufacturers can work together seamlessly. This makes it easier to integrate new devices into existing networks.
  • Low energy consumption: Ethernet-APL was designed to have a low energy consumption.
  • Integrated power supply: The Power over Data Line (PoDL) technology within Ethernet-APL allows devices to be powered directly over the Ethernet cable. This not only simplifies installation, but also eliminates the need for separate power cables.
  • Safe in hazardous areas: Ethernet-APL has been designed for use in potentially hazardous areas by meeting high safety standards for explosion protection. This makes the technology suitable for sectors such as the chemical and oil industries.

The "last cartridge" for the digitalization of the field

Ethernet-APL is not just a technological improvement, but a trailblazer for Industry 4.0. It supports data-intensive applications such as predictive maintenance and real-time optimization, which help to increase efficiency and reduce costs. Or to put it in the words of Dr Felix Hanisch, CEO of the user association NAMUR: "For me, Ethernet-APL is the last chance to really achieve digitalization in the field."


Armin Scheuermann

Armin Scheuermann

Chemical engineer and freelance specialised journalist