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Units issue: SCFM and CFM both converted to ft3/min


Lee
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In situations where process historian tags have units of "scfm" (standard cubic feet per minute) and "cfm" (cubic feet per minute), both are converted to "ft3/min" in SEEQ.

This is incorrect, as those are both different units.  "scfm" is a unit of molar flow.  "cfm" (or less ambiguously "acfm" for "actual cubic feet per minute") is a unit of volume flow, which is what "ft3/min" implies.

In practice, the historian shouldn't use "cfm", as that's ambiguous, and there are times it's used to mean scfm and other times it's used for acfm.  Though that's more an issue with the historian than SEEQ.  I would personally find it nice for all three of scfm/acfm/cfm to appear differently in SEEQ, so that I can identify situations where cfm is ambiguous.  But at the least scfm should be a different unit than the other two; I would suggest something like scfm be left as "scfm" in SEEQ.

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