July 28, 2026 (Endress+Hauser release) — Endress+Hauser, in collaboration with Covestro, BASF and Yokogawa, has conducted a further large-scale Ethernet-APL scalability test, extending validation to more complex and heterogeneous process automation environments. The test took place at Endress+Hauser Digital Solutions in Reinach, Switzerland in May 2026.  

Building on earlier multi-vendor testing, the new setup expands the focus from instrumentation density to architectural breadth. For the first time, a Yokogawa CENTUM VP distributed control system (DCS) and Plant Resource Manager asset management system were integrated into a large-scale Ethernet-APL PROFINET test environment, alongside a broader combination of field devices, switches and network infrastructure.  

Focus on architecture scalability under realistic conditions

While previous tests confirmed Ethernet-APL readiness under full-load conditions, this one focused on scalability across more complex plant architectures. In addition to peak-load validation, the test scope was extended to include a multi-day stability test phase, assessing 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 which Ethernet-APL offers in real-world, multi-vendor architectures,” said Karl Büttner, Advanced Expert Product Management at Endress+Hauser.  

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  
• Validation of asset management access across multiple rings using a private VLAN architecture  

Multi-vendor integration extended 

The successful integration of the Yokogawa CENTUM VP system broadens the scope of validated DCS environments for Ethernet-APL. At the same time, the inclusion of additional infrastructure components, including Ethernet-APL switches and higher-level network elements, further demonstrates interoperability across a growing ecosystem. 

Operator-driven validation 

With Covestro leading the test and BASF contributing prior test experience, two global chemical producers have now actively validated Ethernet-APL technology under scalable, realistic conditions. This reflects increasing interest in Ethernet-based field communication to support digitalization initiatives that require consistent data access, system interoperability and lifecycle transparency. 

"Ethernet-APL is a key element on our digital transformation journey – it extends high-speed communication into the field, unlocking the data transparency and connectivity needed to fully digitalize our operations. 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,” said Sebastian Mahler, Vice President, Head of Process Control Technology, Covestro. 

“In 2023, BASF successfully demonstrated scalability with 240 PROFINET over APL devices connected in a single Ethernet ring, using ten 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 also demonstrated scalability in 2026 as part of a test led by Covestro and conducted at Endress+Hauser in Reinach, Switzerland,” said Gerd Niedermayer, Senior E&I Engineering Manager at BASF. 

Network setup overview

Interoperability was validated across the control system layer, field devices, Ethernet-APL switches and network infrastructure components. The test setup included a Yokogawa CENTUM VP distributed control system (DCS) with Plant Resource Manager (PRM), Endress+Hauser APL field instruments and Samson APL field positioners, as well as Ethernet-APL switches from R. Stahl, Softing, Phoenix Contact and Pepperl+Fuchs.

Network infrastructure components comprised a Hirschmann switch with a private VLAN for asset management access across rings and Siemens Scalance switches operating as Media Redundancy Protocol (MRP) manager. 

Interoperability was validated across: 

• Distributed control system (DCS) 
• Yokogawa CENTUM VP and Plant Resource Manager (PRM)
• Field devices 
• Endress+Hauser APL field instruments  
• Samson APL field positioners 
• Ethernet-APL switches 
• R. Stahl APL field switch for Ex Zone 1 
• Softing APL field switch 
• Phoenix Contact APL field switch 
• Pepperl+Fuchs APL field switch 
• Network infrastructure components 
• Hirschmann switch with private VLAN for asset management to ring access  
• Siemens SCALANCE switches as Media Redundancy Protocol (MRP) manager