Interview with Long-Standing Member of the PNO Advisory Board, Juergen George about the Past, Present, and Future of Fieldbus Technology
PROFIBUS & PROFINET International (PI) celebrates its 25th birthday in 2015—an organization in which Juergen George from Pepperl+Fuchs was involved from the outset. Over the decades, he has influenced the definition of standards in fieldbus technology through various bodies, committees, and working groups. In celebration of PI's anniversary and George's retirement, we invited him to an interview: What does the future hold for PI? What will he remember most from his eventful career in service of "Mission Fieldbus"?
Mr. George, PROFIBUS & PROFINET International (PI) is 25 years old. Thinking back as a pioneer of the organization, what was the original aim of PI when it was founded and how would you describe the situation at that time in the field of automation?
Even in the 1980s, digital communication already existed for a wide variety of applications, such as for coupling the units in controllers and process control systems. However, there was no way to connect sensors and actuators digitally in the field. HART was primarily used to configure field devices, but less so than fieldbus. Then PROFIBUS was developed as a suitable medium offering interoperability. The existing RS-485 interface—for which no special integrated circuits had to be developed—was chosen for the physical layer.
A lot has been achieved since then. Today around 10 million PROFINET and 51 million PROFIBUS field devices are installed worldwide. Those figures are incredibly impressive. What do you think is the reason for the success of these standards today?
Right from the outset, the focus was on applications in the industrial sector and especially factory automation. The barriers to introducing digital technology are lower in this particular field compared to the process automation sector. PROFIBUS DP is easy to implement and has won acceptance, particularly in the area of programmable logic controllers. Virtually every PLC on the market offers a PROFIBUS connection—at least as an option—and the automation engineers of the future learn how to operate this technology right in college or university.
This development has taken many years. Can you break it down to a few milestones that you believe really set the course for the technology?
Fieldbus technology really took off in the early 1990s. Once PROFIBUS DP was established in the factory automation sector, the requirements for using fieldbus systems in process automation were developed. A general requirements profile was created and the Physikalisch Technische Bundesanstalt then developed and standardized the requirements for supplying power via the bus and a workable version of intrinsic safety by creating the IEC-61158-2 standard and FISCO, which is now part of the IEC 60079 standard. By 1993, this approach was followed internationally by the Interoperable System Project or "ISP." Following the conclusion of this project, this approach was pursued separately by the Fieldbus Foundation and PROFIBUS PA. The PROFIBUS protocol remained unchanged, but this was not the case for the physical layer. At this time, Siemens and Pepperl+Fuchs were the only companies that produced Segment Couplers to connect field devices to the bus. Pepperl+Fuchs Segment Couplers stood out as they were virtually transparent, providing a direct view of the field devices without extensive configuration.
However, the introduction of fieldbus technology in industries such as chemicals and pharmaceuticals was not a sure-fire success. Users required intrinsic safety, a method of ignition protection for hazardous areas, which entailed limiting the power supply and therefore the number of connected field devices on the segment. Working in close collaboration with German chemical and pharmaceutical companies, Pepperl+Fuchs then developed the Fieldbus and Remote I/O System Comparison "FuRIOS." The high-power trunk concept that is well known around the world today was developed on the basis of the results from this study. In this concept, the trunk cable is designed with ignition protection “increased safety” or a comparable version. The field device connections via FieldBarrier —that protect the segment against device short circuit— are intrinsically safe and therefore accessible in hazardous areas without requiring a hot work permit. These concepts led to the development of FieldConnex fieldbus installation technology. The development of PROFIsafe is definitely also worth mentioning.
With the use of Ethernet technology and a particular focus on object-oriented development, PROFINET has already set the course for future success—a future where we can expect even more innovations.
When defining standards, there are many important considerations and different perspectives that need to be taken into account. Can you give us a small insight into the challenges presented by your work in the past 25 years?
Developing the first fieldbus systems required manufacturers to completely change their way of thinking. As the systems needed to be open, there had to be standardization before the products could be sold on the market. Companies therefore took on the burden of development, but this would not automatically give them an edge, as competitors would ultimately benefit from the results of the development. Then national sensitivities came into play. The basis for a fieldbus standard was established in France as early as 1986. This resulted in FIP and WorldFIP, which merged to form the Fieldbus Foundation. At the same time as developments in France, the acceptance of PROFIBUS took a step forward in Germany.
Of course, both bodies were convinced that they had developed the best fieldbus. Due to the competing interests at play, the process of standardizing fieldbus systems in Europe became very protracted. In the end, competition in the United States in the form of Modbus resulted in the creation of a European standard. But even this didn't solve the problem. In the process automation sector, a global polarization between PROFIBUS and Fieldbus Foundation developed despite the common physical layer. The name "fieldbus wars" gives a really good idea of the intensity with which the camps argued with each other. Naturally, these unpleasant circumstances led to uncertainty among users. Today, nearly all of the competitors supply both technologies on customer request. I would now describe the parties as co-existing in a technology sense. In any case, both systems remain equally powerful.
What does the future hold for the two standards and the organization itself? What are the major issues that the industry will face in the long term?
Although they are used on a mass scale in applications, the spotlight is shifting slightly from proven technologies such as PROFIBUS DP and PA, as well as Foundation Fieldbus H1. The concept of PROFINET goes beyond simple application of Ethernet. Market growth rates for this technology are currently high and there will soon be further innovations, such as ignition protection for PROFINET. Right now, various companies are trying to bring PROFINET field devices into the process automation sector. PROFINET and the fieldbus systems are used for Industry 4.0, but this goal still needs much more far-reaching technologies. It is no longer about the pure transmission of measurement and control data—machines themselves need to know things like how devices are designed in the production network. A machine-readable syntax such as that from eCl@ss is required.
IO-Link is relatively new in the factory automation sector but is establishing itself very well. As a fieldbus-neutral technology, it is a sign of the new way of thinking in a "post-fieldbus war" age. To avoid an additional organization, this technology is provided by the PROFIBUS User Organization or PNO. The PNO maintains Interbus; an AS-Interface is integrated. PNO's political stance is based on the idea of adapting technology instead of promoting competition. The organizational conditions for this approach were established years ago.
In 25 years, a number of extraordinary things must have happened. What moments do you particularly remember on a personal level?
In 1997, I was welcomed onboard the PROFIBUS PA company committee by ABB and founding member Siemens. At the time, the committee was seen as a casual team that managed the development of PROFIBUS PA. I spent twelve years in this loose team that was not a formal part of the PNO (laughs). I joined the PNO working group on "intrinsically safe fieldbus" in 1996. Our PROFIBUS PA commissioning guidelines were replaced only recently in favor of new documentation. In 2005, I was voted onto the PNO advisory board for the first time at the Hannover Messe trade fair and was confirmed in office twice over the years. Working with various advisory board colleagues was always very constructive, fair, and pleasant, and it is something that I am sure I will remember fondly.
Incidentally, I still have a badge saying "10 Years PROFIBUS—Your Future Is Us" in my desk drawer. That anniversary was celebrated with a ceremony at the Interkarma trade fair in Düsseldorf. The star guest was Heinz Riesenhuber, the former Federal Minister of Scientific Research who is still known today for his trademark colorful bow tie (laughs). The fact that he—in contrast to the previous speakers from the industry—left the podium during his lecture and spoke among the audience caused a small sensation back then. From being ten years old, we have now moved on to age 25. This anecdote shows us how much our entire culture has changed since then and at the same time, how long-lasting such technology developments are. The great thing is that after all these years, we still have plenty of room for growth and improvement, and developing common standards for interoperability has resulted in companies being willing to cooperate with each other, which is an essential factor in ensuring growth.
Mr. George, thank you for taking the time for this short interview. We wish you all the best in your well-deserved retirement!