The Economic Viability of Ethernet-APL

1. Why seamless Ethernet communication to the field can already pay off today
2. What is Ethernet-APL?
3. Ethernet APL Costs: Why Device Prices Don't Tell the Whole Story
4. From HART to Ethernet-APL
5. The Economic Relevance of Ethernet-APL’s Technical Features
6. Project-Level Factors in the Ethernet-APL Business Case
7. Independent Study Confirms Ethernet-APL’s Competitive CapEx
8. Beyond CapEx: Economic Benefits During Plant Operation
9. How Softing Supports Ethernet-APL Projects
10. When Does Ethernet APL Make Sense?
11. Conclusion: Looking Beyond Hardware Costs
12. Frequently Asked Questions

Ethernet-APL enables seamless Ethernet communication to field devices, faster access to diagnostic data, and a simpler path toward digitalization. Despite growing industry support, many plant operators still ask whether it already makes economic sense.

Ethernet-APL field devices often cost more than conventional 4–20 mA instruments. If hardware price is the only factor being considered, the business case appears difficult to justify. But field device costs tell only part of the story. Engineering, installation, commissioning and long-term plant operation account for a significant share of a project's total investment. These are exactly the areas where Ethernet-APL can create measurable savings.

By extending Ethernet directly to the field level, Ethernet-APL simplifies system integration, reduces engineering effort and creates continuous access to process and diagnostic data. This enables applications such as Plant Asset Management, condition-based maintenance, Predictive Maintenance and future AI-driven process optimization. The key question is whether savings across the project can offset higher device costs.

Key Takeaways

• Ethernet-APL extends standard Ethernet communication directly to field devices, even in hazardous areas.
• Individual Ethernet-APL field devices are often still more expensive than comparable 4–20 mA instruments. As adoption increases and production volumes grow, this price gap is expected to narrow.
• The business case is created across the entire project. Lower engineering effort, simplified installation and faster commissioning can already compensate for higher hardware costs.
• Continuous access to field and diagnostic data creates the foundation for Plant Asset Management, Predictive Maintenance and future data-driven applications.

Ethernet-APL (Advanced Physical Layer) extends Ethernet communication directly to the field level. It delivers 10 Mbit/s communication over a two-wire intrinsically safe cable, while transmitting both power and data over the same cable, even in hazardous (Ex) areas.

Unlike traditional fieldbus architectures, Ethernet-APL does not introduce another communication layer. Instead, it extends Industrial Ethernet all the way to the field device, allowing protocols such as PROFINET and EtherNet/IP to use the same physical infrastructure. The result is a simpler communication architecture with fewer protocol transitions and easier field-device integration. These characteristics provide the basis for measurable economic benefits across the project lifecycle.

Purchasing costs are often the first point of comparison. Yet field devices are only one part of a process plant's investment: Engineering, installation, commissioning, and the use of process and diagnostic data also shape project economics. Considering these phases together changes the financial picture, particularly in greenfield projects.

Designing the communication architecture around seamless Ethernet communication from the beginning can simplify engineering, reduce installation effort, and improve long-term operating efficiency. At the same time, process values, diagnostic information and device data become continuously available for applications such as Plant Asset Management and condition-based maintenance. The Ethernet-APL business case is therefore not based on cheaper field devices. It is based on lower project effort today and a communication infrastructure that continues to create value throughout the plant lifecycle.

Ethernet-APL builds on the evolution of field communication and on experience with 4–20 mA, HART and PROFIBUS PA. Each generation aimed to make more field-device information available and simplify engineering, commissioning and maintenance.

Field Device Communication at a Glance

HART: The First Step Toward Digital Field Communication

HART added digital communication to the existing 4–20 mA signal without changing the installed infrastructure. For the first time, maintenance teams could access device parameters and diagnostic information remotely while continuing to use proven analog instrumentation.

That backward compatibility is one of the main reasons why HART remains one of the most widely used communication standards in the process industry. Its limitation is communication speed. Reading large diagnostic datasets or configuring devices can still take several minutes.

PROFIBUS PA: Fully Digital Communication

PROFIBUS PA took the next step by replacing analog communication with a fully digital fieldbus. Power and communication are transmitted over the same two-wire cable, allowing multiple field devices to share one network segment.

Compared to conventional analog installations, this reduces wiring effort while providing significantly more process and diagnostic data. The trade-off is a dedicated fieldbus infrastructure that requires specialized engineering tools and fieldbus expertise.

Ethernet-APL: Bringing Ethernet All the Way to the Field

Ethernet-APL continues this evolution by extending standard Ethernet directly to field devices. Rather than introducing another communication layer, it allows Industrial Ethernet protocols such as PROFINET and EtherNet/IP to operate across a single physical infrastructure from the control system down to field instruments, including those installed in hazardous areas.

For plant operators, the biggest advantage is not simply higher bandwidth. It is the ability to integrate field devices into the same Ethernet architecture that already connects controllers, DCS systems and higher-level applications. The result is a simpler communication architecture with fewer protocol transitions, less engineering effort and easier access to field data.

The technical capabilities of Ethernet-APL are well documented. But technical specifications alone rarely justify an investment. The more important question is: how do these features simplify engineering, reduce project effort or improve plant operation? That is where the technology begins to create measurable business value.

Higher Bandwidth Is Only Part of the Story

Most discussions focus on Ethernet-APL's 10 Mbit/s speed. Yet bandwidth alone does not create the business case; process values require very little of it. The economic benefits become apparent during engineering and maintenance. Consider a radar level transmitter: retrieving an envelope curve over a conventional HART connection can take several minutes. Using Ethernet-APL, the same information is available within seconds. Across hundreds or thousands of field devices, these time savings add up during parameterization, diagnostics and commissioning. 

Simpler Networks Mean Simpler Engineering

Equally important is how Ethernet-APL simplifies communication architectures. Traditional fieldbus systems require dedicated communication networks, specialized engineering software and fieldbus-specific expertise. Ethernet-APL integrates field devices directly into Industrial Ethernet infrastructures. Many engineering tools and workflows that are already familiar in Industrial Ethernet environments can therefore be used consistently from the control system down to the field device. For engineering teams, this reduces complexity. For organizations facing a shortage of experienced automation specialists, it also reduces dependence on highly specialized fieldbus expertise.

Why Greenfield Projects Benefit Most

The full potential of Ethernet-APL becomes visible when communication architecture is planned from the outset. In greenfield projects, Ethernet-APL can be implemented as a native Ethernet infrastructure reaching every compatible field device. Additional gateways, protocol conversions and parallel communication networks can often be reduced or eliminated. This not only simplifies engineering. It also creates a digital foundation that supports Plant Asset Management, condition-based maintenance and future digitalization initiatives throughout the lifecycle of the plant.
 

The business case should be evaluated at project level, not device level. The decisive factor is not the cost of an individual device, but the combined savings across engineering, installation, and commissioning.

Engineering: Reduced Design and Integration Effort 

Separate tools, protocol conversions, and specialist expertise increase design and integration effort. Ethernet-APL reduces this complexity by extending Industrial Ethernet to the field level. Engineering teams can work within a consistent Ethernet environment across much of the automation architecture. This can reduce engineering effort, the number of integration points, and the risk of configuration errors.

Installation: Reduced Infrastructure Requirements

Ethernet-APL transmits power and data over the same intrinsically safe two-wire cable. This can simplify field installation and reduce wiring, backbone, and control cabinet requirements. While the savings may be limited in smaller projects, improvements per instrument can result in substantial reductions in installation effort across hundreds or thousands of devices.

Commissioning: Reduced Verification Effort

Commissioning delays increase project costs and can postpone the start of production. Automated loop checks, polarity protection, and faster access to diagnostic information reduce manual verification work and support earlier fault detection. This can make commissioning faster and more predictable.
 

After commissioning, continuous access to field and diagnostic data becomes increasingly valuable. Continuous visibility into device status and process conditions reduces reliance on periodic inspections and reactive maintenance. That makes it possible to detect problems earlier, plan maintenance more effectively and make better use of Plant Asset Management systems.

Where Plant Operators Benefit

Data Becomes a Long-Term Asset

An important advantage of Ethernet-APL is the continued availability of process and device data after commissioning. Continuous process and device data enable Plant Asset Management and condition-based maintenance today. It also lays the foundation for advanced analytics, AI-assisted optimization and new data-driven operating models. In other words, the Ethernet-APL business case has two dimensions. The first becomes visible during engineering, installation, and commissioning. The second unfolds throughout the plant’s operational life.

From Business Case to Implementation

Once the business case has been established, the next question is straightforward: How can Ethernet-APL be implemented in practice? Implementation should support today's operational requirements while providing a foundation for future digitalization. Field devices, network infrastructure, engineering tools, control systems and Plant Asset Management should be considered as one integrated solution.

Integrating Ethernet-APL into Modern Plant Architectures

In a native Ethernet-APL architecture, field devices connect directly to the control system through Ethernet-APL switches. Engineering tools, control systems, and Plant Asset Management applications all access the same communication infrastructure. This creates seamless data paths from the field device to higher-level systems without introducing additional communication layers or protocol conversions. The result is a simpler automation architecture, easier engineering, and continuous access to valuable field data.

Not every project starts with a greenfield plant, however. Many operators are looking for practical ways to modernize existing PROFIBUS PA or 4–20 mA installations step by step. Ethernet-APL supports this approach as well. Migration concepts allow existing field devices to remain in operation while Ethernet-APL infrastructure is introduced gradually, reducing both investment risk and project complexity.
 

Successful Ethernet-APL implementation requires more than selecting hardware. Softing supports plant operators, EPCs and system integrators throughout this process—from communication architecture design to the integration of field devices into engineering, control and Plant Asset Management systems. 

The portfolio includes Ethernet-APL field switches for native greenfield installations and migration solutions that combine Ethernet-APL with existing PROFIBUS PA devices. This enables operators to modernize their field communication step by step while continuing to use installed field devices.

Ethernet-APL is particularly attractive if your project includes one or more of the following:

• A greenfield plant where the communication architecture can be designed from the beginning.
• Hazardous areas that require intrinsically safe Ethernet communication.
• The need to reduce engineering, installation and commissioning effort.
• Large numbers of field devices, where small savings per instrument accumulate across the project.
• Future plans for Plant Asset Management or condition-based maintenance.
• A requirement for continuous access to process and diagnostic data for analytics or AI applications.
• Existing Industrial Ethernet or PROFINET infrastructures that should be extended consistently to the field level.

The more of these conditions apply, the stronger the case for evaluating Ethernet-APL from a project and lifecycle perspective rather than by comparing hardware prices alone.

Ethernet-APL evaluations often focus too narrowly on individual field-device prices. Engineering, installation, commissioning, and operation all contribute to total cost of ownership. Together, they reveal value that a hardware comparison misses. That is why Ethernet-APL should not be viewed simply as another communication technology.

Ethernet-APL can simplify engineering, reduce project complexity, and create a digital foundation for the plant's operational life. For greenfield projects, this can already make Ethernet-APL economically competitive today. For existing plants, it provides a practical migration path that allows operators to modernize their communication infrastructure at their own pace while protecting previous investments.