Global reference data

Reference data is shared information used in supply chain models. Reference data is typically created and managed by administrators and shared across an organization, ensuring that all users have access to a common set of information and agreed standards, and any changes are pushed to all users. Reference data that can be managed in AVEVA Unified Supply Chain includes:

• Material types and traded materials

• Specifications

• Process models

• Markets

• Calculation types

These are listed in a series of pages available from the Reference Data tab in the left-hand pane of the Model Explorer.

Note: You must commit your changes after editing global reference data to make them available to other users.
Other users will do a Get operation to retrieve the updated data and then update their models with the new data.

Externally managed reference data

Some reference data is managed in other tools. Reference data that must be managed in an external tool such as Assay or Process Model Manager includes:

• Units of measure, such as % or ppm.

• Properties, such as Sulphur (Total) and Nickel, and utilities, which are special properties.

• Blend rules.

Units, properties and utilities are discussed in the remainder of this section.

Units

Units of measure belong to categories. Units of measure in the same category can be converted between each other and so have a conversion formula. For example, kg and tonne are units of measure of the mass category and can be converted between each other using the conversion formula 1 tonne = 1000 kg.

If a new unit of measure is required, you must add it to an appropriate category, and provide a conversion formula so that the new unit can be converted to the other units in that category.

Quantity units. Units for amounts of material can be weight-based or volume-based. All materials must have an associated density to allow conversion of units. Conversion is only necessary if the material amount is measured using a different basis than the overall model basis. For example, if the overall model is weight-based and an amount is entered in cubic meters, it is necessary to include the material density to allow conversion to the correct base unit of measure.

Price units. Pricing uses a single currency in all calculations.

Pricing data is either fixed or associated with an amount of material. If the price is fixed, the amount is entered directly using the default currency for the model. For example, the insurance cost for the plant may be fixed and so would be entered directly in $.

If the price is associated with a unit of measure, the amount is entered in the default currency for the model, and associated with an amount of material, either weight-based or volume-based. For example, crude may be entered as a price $/bbl, while hydrogen may be entered as a price $/tonne.

Materials which have a price per unit must have an associated density to allow conversion between weight and volume basis. For example, if crude is entered as $/bbl and the model is weight-based, the crude density is necessary to allow conversion to a weight basis.

Properties

Properties all have units of measure, and thus belong to a unit of measure category. You can enter values for a property in any unit of measure of the corresponding category, and this is converted to a consistent basis using the unit conversion formula.

Properties by default blend linearly. To use a blend index, an appropriate blend rule must be associated with the property within the model workspace (see: Blending). Properties also have a blending basis, that is, by weight or by volume. Property blending occurs based on the relative amounts of each property with respect to the amount of property in the blending basis space. For example, for a volume-blending property the final property value is the weighted average of the property with respect to the volume ratio of each blend component.

If a property blending basis is different from the stream measurement basis, density is required on each stream component to allow basis transformation.