DA items (leafs) are represented in the COM UA Wrapper as Variables. The VariableType depends on the existance of special DA properties as follows:
- AnalogItemType: An item in the DA server that has High EU and Low EU properties or its EU Type property is Analog is represented as Variableof AnalogItemTypein the COM UA Wrapper. The AnalogItemType has the followingProperties:
- EURange: The values of the High EU and Low EU properties of the DA Item are assigned to the EURange Property
- EngineeringUnits: The value of the Engineering Unit property of the DA Item are assigned to the EngineeringUnits Property.
- InstrumentRange: The values of the High IR and Low IR properties of the DA Item are assigned to the InstrumentRange Property
- TwoStateDiscreteType: Anitem in DAserver that hasOpen Label and Close Labelproperties is represented as VariableofTwoStateDiscreteType in the COM UA Wrapper. The TwoStateDiscreteType has the following Properties
- TrueState: The value of the Close Label property of the DA item is assigned to the TrueState Property.
- FalseState: The value of the Open Label property of the DA item is assigned to the FalseState Property.
- MultiStateDiscreteType:An item in the DA server that has its EU Type property as enumerated is represented as Variableof MultiStateDiscreteTypein the COM UA Wrapper. The MultiStateDiscreteTypehas the following Property:
- EnumStrings: The enumerated values of the EUInfo Property of the DA item are assigned to the EnumStrings Property.
- DataItemType: An item in theDA Server that is not any of the above types is represented as VariableofDataItemType in the COM UA Wrapper.
Below are mappings that are common for all item types
- The name of the item in theDA Server is used as the BrowseNameand the DisplayNamefor the Nodein the COM UA Wrapper. See also clause A.3.1.5.
- The ItemId in theDA serveris used as a part of the NodeIdfor the Node. See also clause A.3.1.5.
- TimeZone property in theDA server is represented by a TimeZone Property.
- TheDescriptionproperty value in theDA serveris assigned to the Description Attribute.
- The DataTypeproperty value in theDA server is assignedto the DataType Attribute.
- If the item in theDA server is an array, the ValueRank Attributeis set as OneOrMoreDimensions. If not, it is set to Scalar.
- The AccessLevel Attributeis set with the AccessRights value in theDA server:
- OPC_READABLE -> Readable
- OPC_WRITABLE -> Writable
Note that the same values are also set for the UserAccessLevel in the COM UA Wrapper.