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Span Attribute...is it worth the time?

Question asked by jdelise on Sep 28, 2018
Latest reply on Oct 8, 2018 by Jaison_Rodrigues

The task of reviewing the "important" attributes for approximately 25,000 existing and currently functional points is inevitable for our PI System. In the interest of reducing the effort required to accomplish this task, as well as establishing a setting that's easy to remember, it has been suggested that the Span attribute be kept at its current default value of 100. Our instrumentation includes pressure, flow rates, temperature, rotation, etc. The two measured values that come to mind when considering "the one size fits all" setting of 100 is turbine shaft speed 10,711 RPM (upper limit) and superheated steam at 1,750 degrees F. I understand the advantage of a correct span setting for (1) measured precision and (2) when using Process Book. My question: Other than the two just mentioned, are there any additional reasons for correctly setting the span attribute (as opposed to using 100)?

Thank you,

John DeLise

NY Power Authority

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