The great thing about standards is that there are so many to choose from. Now you can’t tell from the written word that I’m not “saying” this with a wink and a nudge. So just to be clear – I’m serious. Having more than one standard for fieldbuses is a great thing! Of course this notion defies the conventional wisdom that one fieldbus would be the end-all and be-all for everyone. Ok, you’re asking, “What set him off this time?” I just read an article at ControlGlobal.com called “Fieldbus Wars continue.” That title might help sell magazines but I think it does a disservice to the users of fieldbuses.
Let’s begin an analysis by stratifying fieldbuses architecturally. The same communication system that let’s you easily exchange information with a production system is not going to make sense as a system that connects actuators and sensors. So let’s postulate that there are three levels of fieldbuses: Industrial Ethernet, non-Ethernet fieldbuses, and bit-level buses.
It’s hard to imagine Industrial Ethernet replacing AS-i. The economics aren’t there; Ethernet is too complicated and too expensive for such a use. Yet each has its place. If you need to connect to an instrument in an intrinsically safe area, it’s hard to imagine Industrial Ethernet meeting the requirements that non-Ethernet buses can. Yet each has its place.
It looks to me like we need at least three standards to choose from just based on the practical limitations of technology and the requirements for their application.
But what about within each of these three categories? Surely we don’t need more than one standard there! Let’s take the process environment as an example. The two main fieldbuses for process applications are Foundation Fieldbus (FF) and PROFIBUS PA. Although they are both based on the same physics, they differ in their protocols, applications, and even their philosophies. FF allows “control in the field” while PROFIBUS PA does not. PROFIBUS PA allows coexistence with discrete devices (on PROFIBUS DP, because PA and DP use the same protocol); FF does not allow such coexistence. If I’m a user I can make a choice based on my needs. So here are competing fieldbuses taking different approaches. How are the users not better off for having the choice? And I firmly believe that competition promotes more rapid advances in both choices than would otherwise occur. My conclusion is that having competing standards is a tremendous benefit.
It’s a competition, not a war! Competition is healthy.
Well, there’s much more to say about the article that instigated my contrarian tirade, but it must await more available time. Perhaps while I’m flying this week. I’m headed out for Thursday’s PROFINET one-day training event in the Chicago area. Oh, yeah, the boss will be in Columbia, SC for the PROFIBUS one-day training class there on Wednesday. Either of us would be delighted to see you at our class.
It seems that the last item in everyone’s job description is “…and such other duties as may from time to time be assigned.” For me, one of those duties is seeing to the PTO newsletter: PROFInews North American Edition. It was put to bed late last week; look for Issue 9 in the next day or two.