InTech voices

InTech, Apr 2001

LETTERS View from the trenches

The letter from K. Ashok, "Fieldbus conundrum" [February 2001], aroused me to reply. Mr. Ashok, the silence of the silent majority is only a part of the fieldbus problem. Yes, the IEC is manufacturer dominated. Yes, most standards work now. In the U.S., there are some active independent users, but not as many as there were, and there will be fewer and fewer as the user companies lose value for technical competence. They lost patience with the standards process long ago.

I feel obliged to ask, did you have an opportunity to guide the position your national experts took on the IEC vote that gave us the present eight-headed "standard"? It could have been rejected then. The users have been mostly shut out of the voting on IEC standards for years, and never more clearly than on fieldbus issues. There were documented voting irregularities in that vote that would have led to legal charges in the U.S.

In the beginning, ISA SP50 developed a "functional specification" and defined the needs of the user community. ISA-TR50.02, Part 9-2000: Fieldbus Standard for Use in Industrial Control Systems: User Layer Technical Report describes the user view of this effort. The manufacturers saw this as a threat to their market domination, fought this tooth and nail, and missed out on a huge business opportunity. They wanted to control the rate of technical progress to protect their immediate manufacturing plans. Instead, they have held back progress in the chemical process industries.

The users would not lightly abandon the well-known makers of proven transmitters. We learned long ago that buying sensors on price was too expensive. We also know that a pretty CRT screen does not prove process control knowledge. If SP50 and WG 6 had been able to move to any sort of agreement in the early 1980s, we would be buying the third generation of fieldbus by this time. Instead, we have trouble specifying and using fieldbus even today.

The international manufacturers told us thev would su nort an approved international standard. What the; did not say was that the international standards had to mirror their products in order for them to approve it. And since they controlled the votes, they could and did control the standard.

The process industries have been pretty well kept away from the advantages of fieldbus. Out of the eight offerings, only Foundation fieldbus has any wiring system that is practical in the chemical, petroleum, paper, and waste treatment businesses. Ethernet does not work with fieldbus until we can power the instruments over the wires and use wire runs of at least 100 meters in electrical classified hazardous areas. Field devices have to have screw-type terminal strips for connections. The evil fumes of chlorine, sulfur, H2S, and others just love to eat up copper. Plated terminal screws hold up pretty well. Copper wire of 18 AWG can afford to lose some copper and not fall apart. Class I, Division 1, areas restrict currents, voltages, and capacitance. "Sissy" telephone-style connectors just do not make it in a refinery next to a gasoline tank or next to a chlorinator in a water treatment facility, not to mention the situation around an oceanfront tanker terminal.

Action: Tell your suppliers you know what is going on and are tired of all of this. Tell them that you are looking for control in the field. You want modern control. You deserve modern communications with the process. And tell the boss that poor measurements, suboptimal control, and slow and jerky control valves are eating up your profits.

Cullen Lang ford

Landenberg Pa.

Money talks

Cullen is right on all counts! We have been there. Money buys standards with the current process in IEC. ISA and ANSI rules help somewhat, but the rule that sticks in my craw is the poll tax levied on membership to the U.S. Technical Advisory Group that gets to advise ANSI on how to vote for an IEC, ISO, or ITU standard.

Manufacturers with a vested interest can easily afford the $200 to $500 per year for this tax. They can even afford to pay the tax for some consultants willing to cast a supporting vote for them. The U.K. has this same problem for the BSI. As a result, the U.S. ballot was cast in favor of the eight-- headed monster.

Dick Caro

Dedham, Mass.

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