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Required Reading

Digital February issues of Control Engineering and InTech hit the streets Friday.  Better make that “hit the inboxes Friday.”

In “More power over Ethernet” in Control Engineering, this well-said summary of the impact of Power over Ethernet (PoE) in our field:

Despite the research, “Fieldbus leaders shouldn’t lose any sleep over PoE for now,” says Eddie Lee, national industrial Ethernet product sales manager for Moxa Technologies. “The way it’s used for video, voice over Internet, and wireless will point the direction for its acceptance. Right now, it intrigues a lot of people, and it is filling niche applications, but there is no full-scale migration. Industrially, it’s on the periphery.”

Also in Control Engineering, an excellent PROFIBUS application story – “Poetry in Motion” by Peter Welander.  If you’re my age, you’ll want to sing the title since it comes from Johnny Tillotson’s 1960 hit.  Of course it was already a golden oldie for me the first time I heard it; probably for Peter, too.  This is the story of KA that attendees of the 2006 PTO General Assembly Meeting heard in person from Jim Tomlinson complete with videos.  PROFIBUS and PROFIsafe blended with greasepaint!  A must-read.

Do you read the ads in magazines?  You definitely want to see the ad on page 25 in Control Engineering.

The InTech article “Multibus” opens: “Last time we checked, it was reasonably easy to get a bus transfer in New York, but do not expect that level of ease when doing transfers from one industrial bus to another. More than likely, you’ll get more attitude than a rush hour bus driver.”  I have to point out the exception: PROFINET.  PROFINET integrates other buses quite easily… and with no “attitude.”  See that ad on page 25 of Control Engineering.

The article goes on to talk about proprietary fieldbuses and open fieldbuses.  Somehow they classify PROFIBUS as proprietary and PROFINET as open.  None of the buses they classify as proprietary seem to really be proprietary.  This is one of my pet peeves.  Here’s the dictionary definition of proprietary: “something that is used, produced, or marketed under exclusive legal right of the inventor or maker.”  PROFIBUS and PROFINET were developed in an open consortium including many experts from many companies in many working groups.  It’s usable by anyone without restriction; products can be developed by any company or individual with membership in a Regional PI Association (RPA).  (PI is PROFIBUS and PROFINET International; PTO is one of 25 RPAs.)  The barrier to entry is small, starting at $550 for a company with 10 or fewer employees.  Contrary to this article, PROFIBUS was initially developed by a consortium of 13 companies and 5 universities, not by Siemens.  Yes, Siemens was one of them and they are certainly a tireless promoter of PROFIBUS (and now PROFINET), but there are hundreds of other companies involved now.

The article recites a list of Industrial Ethernet benefits under the subheading “Network Integration.”  These are certainly valid.  And now a word about gateways that are mentioned as a means to connect disparate networks: gateways are ok, but proxies are better.  Gateways are designed by individual vendors to bridge from one network to another; PROFINET proxies are part of the specification and provide consistent mapping from a legacy network to PROFINET.