A.3.1.3 Item

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 Variable of AnalogItemType in the COM UA Wrapper. The AnalogItemType has the following Properties:

• 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: An item in DA server that has Open Label and Close Label properties is represented as Variable of TwoStateDiscreteType 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 Variable of MultiStateDiscreteType in the COM UA Wrapper. The MultiStateDiscreteType has 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 the DA Server that is not any of the above types is represented as Variable of DataItemType in the COM UA Wrapper.

Below are mappings that are common for all item types

• The name of the item in the DA Server is used as the BrowseName and the DisplayName for the Node in the COM UA Wrapper. See also clause A.3.1.5.

• The ItemId in the DA server is used as a part of the NodeId for the Node. See also clause A.3.1.5.

• TimeZone property in the DA server is represented by a TimeZone Property.

• The Description property value in the DA server is assigned to the Description Attribute.

• The DataType property value in the DA server is assigned to the DataType Attribute.

• If the item in the DA server is an array, the ValueRank Attribute is set as OneOrMoreDimensions. If not, it is set to Scalar.

• The AccessLevel Attribute is set with the AccessRights value in the DA server:

• OPC_READABLE -> Readable

• OPC_WRITABLE -> Writable

• The ScanRate property value in the DA server is assigned to the MinimumSamplingInterval Attribute.

Any Properties added to a Node in the COM UA Wrapper are referenced using the HasProperty ReferenceType.