Ethernet-APL has the potential to herald the long-overdue digitalisation of the process field level. The technology makes it possible to implement continuous communication between the field level and the control system as well as the asset management system with manageable effort and based on the familiar fieldbus cable (type A according to IEC 61158-2).
Half the world is continuously networked, but the field level of the process industry seems to be largely resistant to this megatrend. To date, most field devices are connected via 4...20 mA, and even the ageing fieldbuses are only used in a small proportion of plants. However, the launch of Ethernet-APL has fundamentally changed the situation.
Users are pushing for Ethernet-APL
Ethernet APL was developed specifically for process automation and forms the physical layer for Ethernet, which transmits power and data via a two-wire cable. Field devices can be connected in hazardous areas over a distance of up to 1,000 metres.
In principle, any type of industrial Ethernet-based protocol can be used. With a bandwidth of 10 Mbit/s, communication is 300 times faster than with previous fieldbus technology. The TROVIS 3797 from SAMSON offers standardised system integration according to PA Profile 4 with PROFINET.
The openness of the technology allows the implementation of parallel communication channels such as OPC UA. It is therefore no surprise that the most important associations and organisations in the process industry are relying on Ethernet APL as a viable technology for the future; users in particular are pushing for the widespread introduction of this standard.
The reasons for this are obvious: access to device data is practically in real time. The direct connection to the field level enables decentralised configuration and calibration of all assets; devices are automatically recognised, and configuration, diagnostic and process data can be read out at any time and accessed for in-depth evaluation.
At the same time, device replacement and documentation are significantly simplified. The flexible architecture offers easy expansion and enables a significantly higher degree of automation for the entire plant, right up to Industry 4.0 concepts. This results in considerable efficiency gains in numerous areas, which can translate into noticeable cost reductions. Users benefit from the cross-manufacturer interchangeability of field devices. At the same time, increasingly scarce skilled workers are relieved of routine tasks.
One positioner for all valves
SAMSON has been an official industry partner since the APL consortium was founded in 2018 and has been significantly involved in the technical design. Now, with the TROVIS 3797, the valve manufacturer is launching a positioner that supports the standard and thus enables a continuous connection between the control system and the field level. Development of this device with PROFINET communication began in 2019 with field trials at a large chemical company. It is based on the high-end platform of the proven TROVIS 379X product family.
Thoroughly tested for process suitability
Ethernet APL field devices must pass tests on their physical and protocol-specific properties and demonstrate PA profile conformity. Load tests with almost 240 field devices and several control systems have proven the reliability of Ethernet APL technology under realistic conditions.
Each TROVIS 3797 series positioner forms the basis for the use of a digital twin and is therefore in line with Industry 4.0 and IIoT. Digital type plates identify both the valve and the actuator.
The basic technology of the positioner meets the highest standards of the valve manufacturer. Its modular design allows for easy retrofitting and replacement of pneumatic and option modules. Its high air capacity can be expanded in a modular fashion and is designed for both single-acting and double-acting actuators.
With the TROVIS 3797 Ethernet APL Positioner, SAMSON meets all requirements for field-level digitalisation.
Full article available for free download
This article appeared exclusively in atp magazine 11-12/2025 on the NAMUR general meeting and is available for free download.
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