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Datum Type


Providing the right context to a value is essential for correct interpretation. This is increasingly important when changing from document centric to data centric information. The POSC Caesar PLM RDL includes a vocabulary for statement of such context related to properties.

Model content

The blue individuals representing corrosion allowance, normal operating gas density, upper limit design pressure and lower limit allowable rotational speed are all typical examples of properties. The rdf:Type relations to subclasses of the Datum class provide the context.

Numerical value, quantity type, and unit of measure is managed separately, see pattern Physical Quantity.

Interpreted Quantity Datum Design Datum Operating Datum Nominal Normal Quantity Datum with specified Scope Maximum Minimum Range Specifying Quantity Datum Measured Calculated Quantity Datum with specified Provenance’ Average 20 bar upper limit design pressure (CFIHOS) “The highest pressure which a functional or physical object is designed for." Specified 3 mm corrosion allowance (CFIHOS) “A thickness that is the upper limit of allowed corrosion of a metal structure." (a pressure quantity) (a corrosion depth) Continuous Absolute lower limit allowable rotational speed (CFIHOS) “A rotational speed which is the lowest rotational speed at witch the manufacturer’ design will permit continuous operation." 15 rpm (a rotational speed) Regularity Specified Quantity Datum select at most one from each of four aspects normal operating gas density (CFIHOS) “The density of the fluid in gas phase at which a functional or physical object is expected to operate normally." –> density (quantity) of contained fluid driven unit normal speed (CFIHOS) “The rotational speed which is the normal operating speed for the equipment which is driven by the functional or physical object. –> speed (quantity) of driven equipment 2 kg/m3 (a DEPENDENT density quantity) Phase Designating Class (SKOS meta-class) Quantity Datum type type type type qualityQuantifiedAs qualityQuantifiedAs type type type type qualityQuantifiedAs type type qualityQuantifiedAs type