10 key moments in the history of PROFIBUS & PROFINET International. Part 1: Profibus.

Happy Anniversary to PROFIBUS and Profinet International!

Over the past 35 years the Profibus & Profinet International (PI) organization has successfully kept up with the evolution of industrial communications technology. 

From its start in 1989, when the first iteration of the Profibus specification was released, the PI family of industrial communication protocols has evolved by adopting newer technologies and concepts, and by always offering an upgrade path for existing installations.

I wanted to narrate the history of the 35 years long travel of PI, but I quickly realized that it was a massive task better fit for a longer format than this LinkedIn post.

While I was doing the research for this article I realized that Profibus is a twentieth century technology, while Profinet is a twenty-first century solution.

For this reason, I decided to follow a different path: a list of the ten most important features and innovations that enabled the original PROFIBUS fieldbus (in the first part of the article) to the existing PROFINET technology (in the second part of the article) to remain relevant in the ever-changing scenario of industrial communication networks. This list is of course made based on my personal point of view and experience. Therefore, if you think that an important feature is not included in this list, you are kindly invited to mention it in the comments section below.

Having explained the basic idea behind this post, to give readers some points of temporal reference, I chose to include a brief list of world events that took place at those years that these ten features were released.

So, let’s begin:

1989

The year when Profibus DP was released and the same year the non-profit Profibus User Organization (PNO or PROFIBUS Nutzerorganisation e.V.) started to operate. The PNO was the initial Standards Development Organization (SDO) that took care of the continuous Profibus development. He first version of Profibus DP was renamed as DP-V0 when V1 was released some years later. It was the first serial-based industrial communications protocol that offered high speed data transfers and a large address space. 

There were other options like ControlNet and DeviceNet (both based on the ODVA CIP protocol) and Modbus RS485, but none could match neither the 12 Mbps data transfer speed nor the 126 nodes addressing space offered by Profibus DP. And even though the 12 Mbps speed was used in few applications, due to its sensibility to EMC and grounding issues, the most used data transfer speed of 1.5 Mbps was four times faster than any competing option available in the day. An additional convenient factor that favored the adoption of Profibus DP was that RS-485 cable was widely available in the market.

Hardware configuration was done through the use of text-based GSD files. These files contained the necessary information to enable the Master to establish a sequential slave polling routine that allowed cyclical and deterministic communications in the network segments. The adoption of a Master-slave communications method meant that only the Master could interrogate the slaves. While this was a rather outdated path to follow, it proved to be useful because of the inherent robustness of this concept.

The first iteration of Profibus DP was designed to work mainly with Remote Input Output (RIO) systems, which could be designed by following the modular device model implemented in the protocol. I fact, this was the meaning of the protocol’s name: PROcess FIeld BUS Decentralized Periphery.

One notable advantage offered by Profibus DP since its beginnings was the savings in cabling. By reducing the need of parallel cabling, cable costs could be reduced if the RIO systems were mounted as close as possible to the application.

The market was very receptive to Profibus DP and the availability of Profibus DP compatible RIO systems grew exponentially.

In 1995, due to the success of Profibus, the regional Profibus Associations and the PNO join together and form the Profibus & Profinet International (PI) organization. PI’s areas of interest expand beyond Profibus and starts tinkering with Industrial Ethernet technology.

What else was happening in the world:

• February 14th: The first satellite of the GPS system is launched. This satellite is the first of the Block II units which were autonomous. The Block I satellites had been launched a few years ago but were not intended for widespread use.  
• March 12th: Tim Berners Lee invented the World Wide Web. That day he presented the description of an information management system that was based on the HTML markup language and used the TCP/IP protocol stack.
• April 10th: Intel releases its Intel i486 series of CPUs. They offer twice the power of the previous generation i386 CPUs.
• April 21st: Nintendo released the first portable video game console, The Game Boy, with a list price of US$ 90. It featured a CPU working at 6 Mhz and included 4kb of RAM and 4 kb of VRAM.
• April 25th: Motorola released the smallest cell phone so far; the MicroTAC mobile phone, the first one with a foldable design but it still required analog networks. Its list price is US$ 3000. TAC stands for Total Area Coverage.
• August 9th: James Cameron releases the film “The Abyss”, notable for its CGI generated special effects. These effects were created using Adobe’s Photoshop software.
• September 16th: Europe declares that CFC gases are banned from production.
• November 9th: The fall of the Berlin Wall.
• Movies: “Rainman” (Dustin Hoffman and Tom Cruise), “Who Framed Roger Rabbit” (first feature film using blended CGI characters and actual actors. “Dead Poets Society” (Robin Williams).

1996, first half

With strong support from Profibus-DP-V0 end users and suppliers, the new Profibus DP-V1 specification was released in this year. Profibus DP-V1 added multi master functionality, acyclic communication and Application Profiles into the mix.

The first improvement was achieved using two different scan cycles in the network. The primary Master, which is connected to the controller, also known as Class I master, sequentially scans the slaves by address order using cyclic data exchange like in DP-V0.

All the network masters are connected in a Token ring network topology, therefore only the Master that has the token can scan the network. After completing a scan, the token is transferred from the primary master to the secondary master, also known as Class 2 master, who then performs a new scan.

This new scan is done using acyclic communications. This mode allows the secondary master to exchange acyclic data with the slaves, such as configuration and parameterization values and advanced diagnostics information. In this way, the Class 2 master can work as an asset management tool and enables users to make changes in the network configuration mostly on the run, thus minimizing the need for controller restarts. 

As an additional benefit, the acyclic communications mode enables a Class 2 master to perform the remote parametrization and configuration of HART devices, as well as to receive their HART diagnostics. HART devices must be connected to the I/O system using HART capable I/O modules which can tunnel HART messages as acyclic communication through the Profibus DP-V1 protocol.

What else was happening in the world

• January 15th: The USB 1.0 standard is published. It offers both a low-speed mode of 1,5 Mbps and a high-speed mode of 12 Mbps.
• January 23rd: The first version of the Java programming language is released.
• February 10th: Garry Kasparov is beaten at chess for the first time by IBM’s Deep Blue supercomputer. Kasparov managed to win three remaining games and tie two others.
• In the 1997 reedition of the challenge, Kasparov only manages to win one of the games, making Deep Blue the first world chess tournament computer champion.
• March: Larry Page and Sergey Brin release the BackRub Web Search Engine. 2 years later, an improved version was presented under the name “’Google”
• March 10th: The Palm Pilot Personal (299 USD) and Professional (399 USD) PDAs are released by Palm inc. (previously a subsidiary of US Robotics). 1 million units would be sold by 1998. They feature a Motorola CPU running at 16 MHz and either 512 K (personal) or 1024 K (professional) of RAM.
• July 7 to 12: At the XI International AIDS Conference, Vancouver, major advances in the management of HIV/AIDS are released, including combination therapy (the "triple cocktail") using protease inhibitors. Within a week after the conference, over 75,000 patients who have been using antibiotics and chemotherapy as treatment against opportunistic infections begin an effective antiviral regimen which greatly increases their immune system strength and therefore their health.

1996, second half

This year proved to be a watershed moment for PI’s technology. Especially for the Process Automation industry.

After a prolonged dispute between European automation suppliers and US-based ones, they finally agreed on the IEC 61158-2 standard that, based on the PROFIBUS PA application profile, led to the release of the PROFIBUS-PA (Process Automation) and its competitor FOUNDATION Fieldbus field communication protocols. Both fieldbuses used the same physical layer, therefore they could use the same infrastructure components, but required specific compatible controllers and field instrumentation.

Profibus PA devices are smart field devices that offer advanced features like remote configuration and parameterization, advanced diagnostics and can work as multivariable devices.

PA technology offered advanced smart functionalities similar to those delivered by HART technology, but with a nearly 30 times faster data transfer rate of 31,25 kbps, simpler installation and eliminating the need for HART multiplexers.

By using the Manchester Bus Powered (MBP) encoding, Profibus PA technology could deliver both power and communications to the connected field devices through a single twisted and shielded two wires cable (Type 1 Cable) and, with the correct hardware, could also be intrinsically safe for use in classified areas up to Zone 1.

The issue of the use of different data transfer speeds for Profibus DP and Profibus PA technologies was addressed using different types of linking devices (links and couplers) that worked like network proxies between the two different physical layers.

These linking devices were being continuously improved by their manufacturers and in their final versions allow the use of Profibus PA segments with Profibus DP segments working at 12 Mbps.

The integral approach used by PI for Profibus technology offered a coherent, fully compatible, and integrated single protocol solution for the automation industry, which covered everything from the controller to the field devices.

One issue sill remained: to make the advanced features of Profibus DP-V1 and Profibus PA accessible to end users, Profibus devices required a device description solution compatible with both cyclic and acyclic communication modes.

Since GSD files could only support cyclic communications, the need for a method to perform the acyclic communications was solved by two different approaches that we will describe later.

What else was happening in the world:

• Jul 3:  North Carolina's WRAL-TV became the first TV station in the United States to broadcast a digital HD signal.
• August 10th: The first official MP3 file is shared through an IRC (Internet Relay Chat) network.
• October 3rd: A supermassive black hole was discovered at the center of our galaxy.
• November 1st: The Digital Versatile Disc (DVD) technology is released. The VHS market starts its collapse. By 2000 no more VHS players are made.
• December: the Federal Communications Commission (FCC) adopted the Advanced Television Systems Committee (ATSC) Digital TV standard for terrestrial broadcasts. The signal can transmit HD video at 1920x1080 pixels with 5.1 surround sound.
• Over the course of the year, the following web technologies became available: CSS or Cascading Style Sheets, ICQ relay chat, the PNG (Portable Network Graphics) image file format and the My SQL database management system.
• The first broadband internet connection services based on cable modem and DSL technologies became available to the public.
• At the end of 1996, the 36 million Web users surpassed the 30 million users of France’s Minitel, until now the most popular online system. By the end of the decade, the Web will hit 360 million users. By 2010, two billion.
• Movies: “Independence Day” (Will Smith, Bill Pullman, and Jeff Goldblum), the Coen brothers “Fargo” and the first Tom Cruise’s ‘Mission Impossible”
• Ukraine dumps its soviet era nuclear arsenal and becomes a non-nuclear nation. (the process starts in 1994 and ends in 1996)

2000

The first solution that became available to deal with cyclic and acyclic communications was to use EDDL (Electronic Device Description Language) technology, which is based on the DD (Device Descriptor) technology used in the HART protocol.

It is based on the use of EDD files (Enhanced Device Descriptor), which are text files created using the EDDL language to describe the digital communication characteristics of smart field devices such as device status, diagnostic data and configuration parameters. These descriptions are transferred to the system's host, which must feature a EDDL interpreter or parser. This interpreter uses the information contained in the EDD file to create an engineering environment able to support any type of device, from any supplier and through the use of any communications protocol.

EDDL based EDDs are compatible with all platforms and systems, because they contain only text based descriptions of the device they represent. That flexibility made them the preferred option for DCS and PCS suppliers, because it meant that a supplier did not had to develop a configuration software tool for each new device. Suppliers just had to create a device description text file using the EDDL language. The Host EDDL interpreter would create the device's UI using an embedded parser.

The look and feel of EDDL files can vary between different control systems because the way they are rendered depends on the quality of the system’s EDDL parser.

EDDL device descriptors can manage both cyclic and acyclic communication modes and can also work in a mixed configuration i.e., using GSD files for cyclic mode and EDDL files for the acyclic mode.

Although EDDs are text based descriptors, the EDDL language can offer advanced graphics in the UIs created by the system's EDDL interpreter, including advanced device setup wizards.

EDDL technology is described in the IEC 61804-2 standard.

What else was happening in the world:

• Vladimir Putin is elected as the Russian Federation’s second president (January 1st).
• January 1st: The Y2K scare passes away almost unnoticed.
• January 3rd; The Peanuts comic ends after its creator’s sudden death. Charles M. Schultz had been creating the strip alone for 50 years.
• February11th: The dotcom bubble peaks; America Online acquires Time Warner by 138 billion USD. The value of the conglomerate reaches 220 billion USD in 2001. After a 99 billion USD reported loss in 2002 the value of the corporation will fall as low as 20 billion USD in the same year.
• March 4th: Sony launches the PlayStation 2 in Japan. The US launch would be in October and the European in November. It would become the best-selling gaming console in history with 180 million units sold. The inclusion of a built in DVD player was a strong purchase reason, and the device helped the adoption of the DVD format for home consumption.
• ·March 14th: Stephen King’s “Riding the bullet” becomes the first published e-book. With a list price of 2.50 USD more than 400000 copies are downloaded in the first 24 hours. The overload made the publisher’s servers crash. The e-book faulty encryption method also crashed Stephen King’s nerdy audience computers.
• June: The first draft of the human genome is announced. His draft was the result of a years long project (The Human Genome Project) undertaken by a worldwide team of life scientists with the goal of finding treatments for genetical disorders and diseases and improving our understanding of human evolution.
• June 9th: Microsoft launches the Windows Me OS; it is received by users with a Mehhh.
• September 1st: The Nokia 3310 GSM cellphone becomes available. Its feature set, durability and ease of use made this device one of the best-selling phones ever, with 126 million units sold worldwide. The phone had a list price of 48,50 USD although the price would be quite lower if acquired with a long-term plan.
• September 13th: Apple presents the first Public Beta of the new Mac OS X, the long-waited replacement of the practically obsolete Mac OS 9 still in use.
• November 2nd: First mission of the ISS (International Space Station). A crew of three, one American astronaut and two Russian cosmonauts, arrive to the station in the Soyuz TM-31 spacecraft and stay for 136 days in orbit.  The ISS has been continuously occupied by humans since then.
• December 15th: The Chernobyl Nuclear Power Plant is finally closed, completely.
• Movies: “Mission Impossible 2”, Ridley Scott’s” Gladiator”, Tom Hank’s “Castaway" and the first "X-men" movie. 

2001

The second solution available to deal with the cyclic and acyclic communications issue was FDT/DTM technology, developed by the FDT Group SDO.

The FDT/DTM approach relies on software packages. This method uses a software-based framework as a container for DTM files, which are software-based device descriptors.

DTMs work like drivers, and they enable the interaction between the framework and the field devices, therefore enabling the use of acyclic data for configuration, parameterization and device diagnostic purposes, while GSD files deal with cyclic data.

There are various types of DTMs that represent physical devices. By the interconnection of these DTMs, end users can create a digital representation of the actual hardware used for the operation of a fied device.

Specific applications can be run on the framework, making this approach best suited for complex applications without having to rely on the system to support these applications.

This feature is well suited for the configuration, parameterization and diagnostic of smart devices without native support from the host system. This feature enabled PLC suppliers to offer advanced asset management solutions without the need to update their system software.

FDT technology is designed using a modular approach, the framework application can adopt the form of a stand alone single device configuration tool, a stand alone asset management tool or embedded into the system software.

FDT works like an abstraction layer that hides the inner working of the communication procedures used in the application behind a user friendly interface. This interface works like a process plant's device manager.

Since DTMs are software based, they maintain their look and feel across different systems. This feature can produce reductions in operational costs by simplifying the required training of operators and standardizing support procedures. But this feature implies that frameworks require to be installed in supported platforms i.e. Windows based PCs. Subsequent FDT versions added support for HTML and networked server functionality, thus making FDT technology system independent.

FDT/DTM technology is described in the IEC 62453-2:2022 standard.

What else was happening in the world:

• January 1st: The dotcom bubble implodes and the venture capital market crashes.  Between March 2000 and January 2001, internet related stocks had lost 75% of their value, wiping out 1.744 trillion USD in value. By the end of 2002 the loss had increased to 5 trillion USD.
• March 24th: Apple launches mac OSX, the first native 32-bit consumer OS.
• April 28th: American millionaire Denis Tito becomes the first space tourist visiting the International Space station for a week. He arrives as part of the crew of the Russian spacecraft Soyuz TM-32.
• July 2nd: The first autonomous artificial heart (called AbioCor and manufactured by the firm AbioMed) is implanted in a human being. The test human survives for 151 days.
• September 11th: The World Trade Center twin towers fell after a terrorist attack.
• October 1st: The first 3G mobile network is installed in Japan by NTT Docomo.
• October 23rd: Apple’s Steve Jobs launches the first version of the iPod music player and the iTunes media player, signaling the beginning of the end of the era of music and video distribution by physical media.
• October 25th: Microsoft launches Windows XP, the first 32-bit consumer Microsoft OS.
• November 15th and 18th: Game consoles take over the video game industry as Microsoft’s Xbox and Nintendo’s Game Cube are launched respectively.
• December: CD sales reach their highest level ever. After its release in 1983, when CDs accounted for 0,3 % of total music sales, the CD format peaked at the end of 2001 grabbing 95 % of total music sales. By 2022, the CD market share had dwindled to 2.4% and streaming had reached 85%.
• Movies: The year marks the beginning of the franchise era: The Lord of the Rings trilogy and Harry Potter's "octalogy" are the years hits. Other successes are the first "Monsters Inc." movie, the first Fast & Furious movie, the first Shrek movie, Jurassic Park III and The Planet of the Apes reboot. This was the year when everything on screen becomes the second or third part of something and the start of the sequels and prequels plague that we suffer today.

The end of an era, and the start of a new era

At first sight, it may seem that the fact that Profibus’ useful life reached its life peak in the last years of the twentieth century and that its successor, Profinet, became commonplace in the first decades of the twenty-first century is a casualty.

But this is not the case. Profibus was the result of the first attempt at developing a digital unified automation environment for the industrial automation market, and it achieved spectacular results in that role.

But Profibus was built over old foundations: that is, serial type protocols that used standard industrial components (like RS-485 cables and DB9 connectors) that had been designed more than a decade before and for totally different applications.

The new century brought to the industry the incredibly fast evolving Ethernet technology, and with it all the network technologies that made possible the internet.

Serial based technologies could never reach the economies of scale than were characteristic of Ethernet components and Ethernet performance is still growing in speed, availability and resilience to levels that serial technology could only dream about.

Profibus and Profinet International has continuously been able to offer reasonable upgrade paths for end users of its technologies and this SDO is aware that the future of industrial networking does not reside in communication protocols or physical layers anymore.

The future belongs to those that embrace the efficient and transparent use of data through the plant, in an integrated data-management based working environment that relies on the use of standardized information models.

In other words, we can consider Profibus as the last attempt of analogue technologies trying to keep up with the digital world and think of Profinet as the acceptance that the new century requires embracing digitalization by all of us.

Mirko Torrez Contreras is a Process Automation consultant and trainer. He is a true history fan and addict, so when the idea of doing a chronological resume of the top milestones reached by Profibus & Profinet International (PI) over the last 35 years, he decided to spend a long time checking out dates and facts to ensure that the historic events featured in this article are correct.

But he is also a human being, therefore there may be involuntary mistakes. If you find any omission or error in the "What else was happening in the world" segments of this article please write a comment and the required amendments will be done.

Phoenix Contact sponsors this article. The opinions exposed in this article are strictly personal. All the information required for and employed in this article is of public knowledge.