6.3.1.1.3 DataSetOrdering

The DataSetOrdering defines the ordering of the DataSetMessages in the NetworkMessages. Possible values for DataSetOrdering are described in Table 95. The default value is Undefined.

The DataSetOrderingType is an enumeration that specifies the possible options for the ordering of DataSetMessages inside and across NetworkMessages. The possible enumeration values are described in Table 95.

Table 95 – DataSetOrderingType values
NameValueDescription
Undefined0The ordering of DataSetMessages is not specified.
AscendingWriterId1 DataSetMessages are ordered ascending by the value of their corresponding DataSetWriterIds.
AscendingWriterIdSingle2 DataSetMessages are ordered ascending by the value of their corresponding DataSetWriterIds and only one DataSetMessage is sent per NetworkMessage.

If DataSetOrdering is Undefined any ordering between DataSets and their distribution into NetworkMessages is allowed. Ordering and distribution even may change between each PublishingInterval. If DataSetOrdering is set to AscendingWriterId, the Publisher shall fill up each NetworkMessage with DataSets with an ascending order of the related DataSetWriterIds as long as the accumulated DataSet sizes will not exceed the MaxNetworkMessageSize. The different options are shown in Figure 30.

Figure 30 – DataSetOrdering and MaxNetworkMessageSize

The DataSetOrderingType representation in the AddressSpace is defined in Table 96.

Table 96 – DataSetOrderingType definition
Attribute Value
BrowseNameDataSetOrderingType
IsAbstractFalse
References Node Class BrowseName DataType TypeDefinition Others
Subtype of Enumeration defined in OPC 10000-5
HasPropertyVariableEnumStringsLocalizedText []PropertyType
Conformance Units
PubSub Parameters UADP