6.3.1 General

Syntax References represent established works of other organizations. Such works – among others – can define semantic information, topologies, a language for a code set, or dictionaries and facilitate the programmatic evaluation or the lookup of a quantity or unit e.g. in a dictionary or ontology. They can be publicly defined by standard bodies such as IEC or proprietary (e.g. vendor-specific dictionaries).

The Quantities and Unit Model provides a powerful way to relate quantities and units to such Syntax References using the Dictionary References model defined in OPC 10000-19.

Table 38 lists Syntax References that are applied in certain markets. This list can be extended in future versions. Vendors or organizations can also specify additional Syntax References.

An overview for each Syntax Reference in this table is provided in Annex C.