Endress+Hauser reported July 28 that it recently collaborated with Covestro, BASF and Yokogawa to conduct a further, large-scale, scalability test of Ethernet-Advanced Physical Layer (Ethernet-APL) to extend its validation to more complex, heterogeneous, process-automation environments. The test was conducted in May at Endress+Hauser Digital Solutions in Reinach, Switzerland. 

Building on earlier, multi-vendor tests, this new setup expands the focus from instrumentation density to architectural breadth. For the first time, Yokogawa’s Centum VP distributed control system (DCS) and Plant Resource Manager (PRM) asset management system were integrated into a large-scale Ethernet-APL and Profinet testing environment. They were integrated with a broader combination of field devices, switches and network infrastructures, including higher-level, interoperable elements across a growing ecosystem.

While previous tests confirmed that Ethernet-APL is ready for full-load conditions, this latest test focused on scalability across more complex plant architectures. In addition to peak-load validation, the test’s scope was extended to include a multi-day, stability test-phase to assess sustained network behavior under realistic operating conditions.

“The successful results of this fifth large-scale test give users confidence in the maturity, scalability and flexibility that Ethernet-APL offers in real-world, multi-vendor architectures,” says Karl Büttner, advanced expert product manager at Endress+Hauser.

More specifically, the test environment included:

• Multi-ring Ethernet-APL topologies;
• A broader mix of infrastructure components;
• Cross-vendor system integration including DCS, switches and field devices; and
• Validation of asset management access across multiple rings using a private VLAN architecture. 

Endress+Hauser adds that interoperability was validated across the control system layer, field devices, Ethernet-APL switches and network infrastructure components. These components included:

• DCS including Yokogawa’s Centum VP and PRM;
• Field devices including Endress+Hauser’s APL field instruments and Samson’s APL field positioners;
• Ethernet-APL switches including R. Stahl’s APL field switch for Ex Zone 1, and Softing, Phoenix Contact and Pepperl+Fuchs’ APL field switches; and
• Network infrastructure components, including Hirschmann’s switch with private VLAN for asset management to ring access, and Siemens Scalence switches as a media redundancy protocol (MRP) manager.  

With Covestro leading the test and BASF contributing prior test experience, two global, chemical producers validated Ethernet-APL under scalable, realistic conditions. Endress+Hauser reports this also reflects increasing interest in Ethernet-based field communication to support digitalization initiatives, which require consistent data access, system interoperability and lifecycle transparency. 

"Ethernet-APL is a key element in our digital transformation journey. It extends high-speed communication into the field, and unlocks the data transparency and connectivity needed to fully digitalize our operations,” says Sebastian Mahler, VP and head of process control technology at Covestro. “Taking an active role in this scalability test allowed us to validate the technology under conditions that closely reflect the complexity of our real production environments. The results give us greater confidence in the technology's readiness for deployment in large-scale industrial environments.”

Gerd Niedermayer, senior E&I engineering manager at BASF, adds, “In 2023, BASF successfully demonstrated scalability with 240 Profinet-over-APL devices connected in one Ethernet ring, using 10 field switches and control systems from ABB, Honeywell and Siemens. Emerson was added in 2025. With the successful completion of the latest tests, we can now confirm that Yokogawa has also demonstrated scalability in 2026 as part of the test led by Covestro and conducted at Endress+Hauser in Reinach.”