Control Engineering

Peter Welander

The magic 20 million
August 6, 2007

Last week, as advertised, I attended the Profibus Trade Organization (PTO) General Assembly meeting in Scottsdale. (Yes, Scottsdale in August. It even rained.)

The theme of the meeting was "20 million," meaning that there are now 20 million installed Profibus nodes worldwide. OK, what does that mean exactly? The number comes from counting the ASICs produced for installation in Profibus enabled devices. (Apparently there are some producers that sell devices without the ASIC, so the chip count probably understates the number slightly.) A Profibus enabled device pretty much has to communicate via Profibus, so there is no way to use the device without the network, hence the "installed" claim. (This is in contrast to HART enabled devices where those functions can and usually are ignored.)

The 20 million figure exists on its own and seems to have a valid basis, so I will accept it at face value. The next claim is more interesting and potentially controversial. Profibus claims a 46% market share for fieldbusses. That number requires a bit more analysis. (If I get this wrong somehow, I am sure Carl Henning will let me know.)

The tricky part isn't so much what you do count in the total market, but what you don't. Obviously things like Foundation Fieldbus and DeviceNet are counted, but other things are not. I didn't manage to write down all the names that are included, however, here are some names that are not counted:

• HART
• AS-i
• Modbus
• CAN Open

PTO has been saying for a long time that HART is not a fieldbus. AS-i is dismissed as strictly bit-level. Modbus and CAN Open are considered sort of a fieldbus, but really more of a messaging system and therefore they don't compete in the same arena. PTO is only interested in comparing Profibus to other systems that can do the same things. OK, that's understandable. While it might make for some interesting arguments, the market share issue is only tangential to the real story.

The story that they were communicating to the assembled troops was this: Profibus has gone mainstream. When there are that many installed nodes, how much more does anyone have to see to realize that this is proven technology? One attendee who represented a large instrumentation supplier said that most end users still want good old 4-20 mA for MRO projects, but he noted that requests for new projects are clearly tipping toward digital communication. And so it should be.

Posted by Peter Welander on August 6, 2007 | Comments (0)