The IrdiDictionaryEntryTypedefined in Table 3is used to represent dictionary entries that use standardized semantic identifiers that conform with International Registration Data Identifiers (IRDI) defined in ISO/IEC 11179-6.

Standardized semantic identifiers are locale independent strings typically specified in international standards like IEC CDD (Common Data Dictionary) (IEC 61987). In order to avoid conflict with various name spaces in these identifiers, the registration authority identifier part of the string used shall be based on ISO 29002-5.

Figure 2shows the general structure and syntax defined by ISO/IEC 11179-6, ISO 29002-5 and ISO/IEC 6523.

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Figure 2– IRDI overview

Examples for IRDI strings defined by standards using the IRDI format

IEC CDD 0112/2//a/61360_4#AAE867#001 Proximity switch, Output current

ISO 55980112-1-a-18582#KAA802#s Pneumatic value

eCl@ss 0173/1///#02-8AD792#s Inductive distance sensor, Design of analog output

Table 3– IrdiDictionaryEntryType Definition

Attribute

Value

BrowseName

IrdiDictionaryEntryType

IsAbstract

False

References

NodeClass

BrowseName

DataType / TypeDefinition

ModellingRule

Subtype of the DictionaryEntryType defined in OPC 10000-5.

Conformance Units

Address Space Dictionary IRDI

The identifier in the respective external dictionary shall be a unique string. This identifier is used for the NodeIdand the BrowseName Attributesof instances of the DictionaryEntryType. The IdentifierTypeof the NodeIdshall be STRING_1 with the identifier from the external dictionary as the value.

The namespace “http://opcfoundation.org/UA/Dictionary/IRDI” shall be used for instance of the IrdiDictionaryEntryType. Subtypes may define different namespaces.

The identifier shall be immutable; meaning that it shall not be reassigned to a different dictionary entry within the scope of the namespace in future versions. Data dictionaries may be publicly defined by standard bodies such as IEC or proprietary (e.g. vendor-specific dictionaries).