RE: [Maybe spam] Common schema units of measure - Use Option 2 plus
No - but I think we should include it
How do we think its spelt ppm (PpM) (ppM) you can only chose one
ppm belongs to the Ratio (Dimensionless unit) such that 1000 ppm is 0.001 which is 0.1%
However with these types of units there is ambiguity in what kppm means is it k(ppm) or (kp)pm, thats why its generally not defined as a unit term
Note IEEE SI10 says do not use ppm, ppb or ppt (parts per Billion) or (parts per Trillion) because Billion and Trillion have different values in different countries!!
However since 1 million is universially recognised as 1e6 I can not a problem with ppm apart from the prefix issue
Chris
> -----Original Message-----
> From: Stephen.Osella@ni.com [SMTP:Stephen.Osella@ni.com]
> Sent: 15 December 2005 14:31
> To: stds-scc20-atml@listserv.ieee.org
> Cc: Gorringe, Chris
> Subject: RE: [Maybe spam] Common schema units of measure - Use Option 2 plus
>
> Does the schema allow a unit for "Parts Per Million" i.e., PPM ?
>
> Stephen Osella
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> if (!good()) break;
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> <Chris.Gorringe@r
> acalinstrumentsgr
> oup.co.uk> To
> Sent by: <stds-scc20-atml@listserv.ieee.org>
> owner-stds-scc20- cc
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> Subject
> RE: [Maybe spam] Common schema
> 12/15/2005 04:07 units of measure - Use Option 2
> AM plus
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> Units should always be units (defined in some standards somewhere) and
> therefore we need to maintain a list of supported units
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> We can add (either at the base class or by deriving types) historic units
> Ins, ft, lbs, jerk etc. but these should ALWAYS be unit values references
> to some standard
> The modification or qualifier discussed I see needs to be available and
> should include the following (taken from IEEE 1641-2004)
>
> trms (true root means square)
> pk_pk (Peak to Peak)
> pk (Peak)
> pk_pos (Positive peak same as peak)
> pk_neg (Negative peak)
> av (average)
> inst (instantaneous)
> inst_max (instantaneous maximum value)inst_min (instantaneous minimim
> value)
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> Note Peak values pk_pos, peak_neg, are w.r.t. the average value and are not
> absolute values, i.e. a peak of pure sinwave is its amplitude removing and
> DC-offset
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> The need for a free text 'modifier' is therefore to hold information which
> is neither the 'Unit' or the 'quallifier' information examples of which I
> would welcolme
> Regards
> Chris
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