Ethernet APL: The quantum leap for valves and actuators

First valve with the TROVIS 3797 positioner undergoing testing at the SAMSON factory in Frankfurt (Image source: SAMSON)

They are indispensable in the process industry: valves, fittings, and their actuators form the backbone of every plant. Without them, nothing works, and stable production is only possible thanks to their precise control. Nevertheless, this crucial field level has remained surprisingly “analog” for a long time. While most areas have long been networked, positioners and actuators often still work with the tried-and-tested 4...20 mA signal. Even fieldbuses—once hailed as a modern advance—have remained marginal solutions in many places.

Ethernet APL (Advanced Physical Layer) is now changing this fundamentally. The technology has the potential to lead the field level into the digital future – without any costly infrastructure changes. It uses the familiar two-wire cable (type A according to IEC 61158-2), transmits power and data simultaneously, and achieves ranges of up to one kilometre, even in potentially explosive areas. For operators, this means no expensive rewiring, but smart, uncomplicated networking.

Smart valves: networking and diagnostics in real time

Ethernet APL opens entirely new possibilities for valve manufacturers and plant operators. Positioners such as the TROVIS 3797 from SAMSON can be integrated directly into the control system—without detours, without additional bridges, and with full PROFINET support according to PA Profile 4. This means that every valve, including the actuator, can not only be controlled, but also configured, calibrated, and monitored during operation.

A practical example: A pneumatic actuator is equipped with a TROVIS 3797. Via Ethernet APL, it not only supplies the position value, but also important diagnostic information – for example, on the air supply, tightness, or deviations in control behaviour. For maintenance personnel, this means that problems are detected early on, allowing them to react in time before production downtime occurs.

TROVIS 3797: a genuine voice in the industry 4.0 concert (Image source: SAMSON)

And best of all, the positioner adapts flexibly to any task. Whether single-acting or double-acting, small control valve or large-calibre shut-off valve—the modular concept makes everything possible. Pneumatic and option modules can be retrofitted, and the air capacity is scalable. This makes the positioner a “universal tool” for a wide variety of valves in the field.

Flexible, fast, digital: the new generation of position controllers

The speed is also impressive: at 10 Mbit/s, Ethernet-APL is around 300 times faster than conventional fieldbus systems. This opens the possibility of reading device data in real time and using communication channels such as OPC UA in parallel. This not only provides process values, but also deeper insights for asset management and Industry 4.0 applications.

Particularly exciting for operators of large valve parks: digital type plates clearly identify the valve and actuator. Replacing a device becomes almost a plug-and-play process – the system automatically recognizes the connected valve, loads the appropriate configuration, and documents everything automatically. For companies, this means a noticeable reduction in routine tasks and more freedom for their already scarce skilled workers.

From positioning device to digital twin

Each TROVIS 3797 forms the basis for a digital twin. This transforms a conventional valve into an intelligent asset that provides transparency regarding its status and can be seamlessly integrated into predictive maintenance concepts. This offers considerable advantages, particularly in chemical and pharmaceutical plants where maximum availability is crucial.

The practicality of the technology has been proven in extensive load tests: around 240 field devices and several control systems worked in parallel under realistic conditions – without any failures. Ethernet-APL thus demonstrates that it is much more than just a vision. The technology works reliably in demanding everyday plant operations.

SAMSON has been an active partner since the APL consortium was founded in 2018 and has played a key role in shaping its development. The TROVIS 3797 is based on the high-end platform of the proven TROVIS 379X positioner family and was already tested in field trials at a large chemical company in 2019. Today, it exemplifies how digitalization can be consistently implemented down to the smallest details in the world of valves.

Ethernet APL ends the digital isolation of the field level. Valves, actuators, and positioners become part of the central nervous system of a plant—with direct connection to the control system and complete transparency. For operators, this means greater efficiency, fewer downtimes, and noticeable cost advantages. At the same time, new perspectives are opening for manufacturers and maintenance personnel in the areas of smart services and digital twins.

In short: With solutions such as the TROVIS 3797, valves finally have a real voice in the industry 4.0 environment. And anyone who has experienced how meaningful a “talking” valve can be will hardly miss the days of silent 4...20 mA signals.