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Development of Ethernet-APL (Advanced Physical Layer) heralds an era of more widespread adoption of advanced automation technology Dr. Michael Magerstädt, Ralf Haut, and Dr. Christoph Spiegel report
The Industrial Internet of Things (IIoT) and Industry 4.0 have trended in process industry conversation over the last several years. There is growing excitement as experts throughout the industry have recognised how greater automation in process control has the potential to be extremely useful.
As a generation of experienced engineers retires and companies look to keep operations as streamlined and self-sustaining as possible, the concepts behind IIoT and Industry 4.0 have taken off.
Large companies throughout the industry have begun investing a great deal of money in IIoT and Industry 4.0 improvements. However, without standardised technologies and common infrastructure, widespread rollout has been extremely difficult.
Now, a consortium of companies is moving to standardise an Ethernet-based physical layer for data transfer in demanding process industry applications, with the goal of more widespread adoption of advanced automation technology at every level of process control.
NAMUR Open Architecture
Automation is a critical source of increased safety and efficiency in the process industries, especially as the industry has shifted from a model of employing a large number of highly-trained and expert engineers to manage processes to more streamlined operations with more autonomous technologies.
While automation continues to be managed and overseen by experts, different data must be accessible to different levels of an organisation.
The Germany-based User Association of Automation Technology in Process Industries (NAMUR) uses the Purdue reference model, commonly called ‘automation pyramid’, as reference for their NAMUR Open Architecture (NOA) approach.
The NAMUR pyramid is applied in the chemical industry throughout Europe and China, and in some facilities in North America, to achieve higher operational stability and plant availability through strict separation of responsibilities into levels.
Components must be configured so that data can flow upwards from the field through basic automation and through management to company leadership.
Through this system the process control system (PCS) can be programmed. The NAMUR pyramid is used to manage not only daily operations but also maintenance intervals, emergencies, and more by filtering necessary information to management and leadership.
The pyramid represents the data flow that stems from the safe and reliable first channel of deterministic IO data.
Moving into the era of the IIoT, also known as Industry 4.0, chemical companies have recognised a need for data to come out of the NAMUR pyramid and go to other recipients for broader-scale process support.
So, due to the given, historic architecture, there is a need for a second channel to provide access to additional diagnostics and to process data without interfering with the existing automation architecture. This includes monitoring and optimisation data, enabling plant engineers to ensure that equipment and processes are running in their optimum ranges, maintenance timing is optimised, and plant efficiency is increased.
For example, flow meters might provide their primary (or ‘first-channel’) data about flow that is critical to the minute-by-minute plant process, but also might provide additional data on density, temperature, and more that can be analysed for plant optimisation.
Thus, NOA is a strategy to achieve the goal of vertical integration in process industries through this second channel. In doing so, the goal is to enable the IIoT without compromising core automatisation loops described by the original pyramid. This second channel provides process improvement data without impinging on the first channel.
The goals of NOA can be realised most easily with combined media, carrying both first and second channel data, based on Ethernet technology.
Advanced Physical Layer and industrial Ethernet
The Ethernet used in our home or in commercial businesses to interconnect smart appliances cannot be used in hazardous areas common to chemical plants and other facilities in the process industry.
A modification of the physical layer carrying this second channel data is required. Ethernet-APL (Advanced Physical Layer) is currently being developed by a multi-national consortium of companies within the process industry. This consortium is working to create a new, suitable bit transfer layer, or physical layer, for the process industry and to standardise Ethernet-APL.
The original target of the Ethernet-APL consortium was to define a technology that fulfills a long laundry list of specific needs: Ethernet-compliance (IEEE 802.3), long wire lengths (up to 3,000 feet), high bandwidth (up to 10 Mbit/s), intrinsic safety (IS; Ex ib for Zone 1, Ex ia for Zone 0 or Class 1 Div 1 and Div 2), and two-wire technology with an intrinsically safe power supply. These requirements cannot all be achieved by a single technology, and so there are two versions of Ethernet-APL one for trunk and the other for spur lines.
Trunk lines are 2-wire Ethernet lines that offer high power supply up to 60 W and can reach lengths up to 3,000 feet into Zone 1 or Div. 2. Spur lines, on the other hand, are 2-wire Ethernet lines that can be intrinsically safe, including the power supply, but which can only reach lengths of up to 600 feet into Zone 0/Div. 1 environments.
While Ethernet-APL is an ongoing standardisation activity with a joint technology development, there are state-of-the-art Ethernet technologies already available which can also cover specific applications in the process industries.
As an example, high performance four-wire instruments with Profinet or EtherNet/IP can serve as the branching or relay points in line or ring topologies with redundancy. KROHNE has these technologies available and is also part of the Ethernet-APL consortium.
As such, the company built demonstrators of instruments that speak eg, Profinet, EtherNet/IP and OPC UA over Ethernet-APL. These instruments can supply both first-channel process data and second-channel optimisation data.
Even the company’s most basic flowmeters have the capacity to be integrated into a NOA-framework plant thanks to their adherence to existing Ethernet and the forthcoming Ethernet-APL standardised designs.
Ethernet-APL is being designed to transport a wide range of protocols, including EtherNet/IP, Profinet, OPC UA, MQTT, HTTP, or even several of these at a time. It enables vertical integration, and supports first- and second-channel data transmission for NOA plants. Development is ongoing, and it is expected that a finalised Ethernet-APL standardised system will be complete in the next several years. This is critically important to the ongoing rollout of IIoT and Industry 4.0 in the process industry and its automation.
Preparing for the Full Integration of Ethernet-APL
As the Ethernet-APL standardisation and design process continues over the next several years, organisations within the process industry will benefit from not just jumping right in with new products and protocols, but taking time to consider what pain points or challenges additional automation of the second channel can bring to their business, and what benefits they can see from that.
What’s more, companies and plants will need to consider what approaches they will be comfortable taking to achieve that additional automation: while some companies will want all equipment to be Bluetooth enabled, others will want only certain instruments to be connected to process control automation systems or to connect only through industrial Ethernet lines.
There are already a large number of options available for process control automation, and those options will only increase as the Ethernet-APL continues to be developed and become standard.
In order to achieve automation technology that is truly useful and functional beyond a single generation of equipment, companies across the industry must be willing to collaborate on standardised solutions and begin to implement those solutions towards the goals of solving problems and optimising plant activities.
In the past several years, the trend towards connected plants in the chemical industry and process industries in general is steadily increasing. In order to sustain that growth, a standardised physical layer of advanced data transfer technology is necessary.
The move towards developing the Ethernet-APL, in support of NOA goals of second-channel data transfer for plant optimisation, is a historic one for the industry that heralds the next generation – and many more generations to come – of industrial automation technology in the process industries.
Dr. Michael Magerstädt is KROHNE, Manager Global Industry Division Chemical, CEO KROHNE Suisse; Dipl. Ing. Ralf Haut is KROHNE, Technical Manager, Global Industry, Division Chemical; Dr. Christoph Spiegel is KROHNE Strategic Product Group Manager.
[1]Dr Michael Magerstädt, Ralf Haut, and Dr. Christoph Spiegel
