XYArrayItemType represents a vector of XVType values like a list of peaks, where XVType.x is the position of the peak and XVType.value is its intensity. XYArrayItemType is formally defined in Table 10.

Table 10 – XYArrayItemType definition

Attribute	Value
BrowseName	XYArrayItemType
IsAbstract	False
ValueRank	1
DataType	XVType (defined in 5.6.8)
References		NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the ArrayItemType defined in 5.3.4.1
HasProperty		Variable	XAxisDefinition	AxisInformation	PropertyType	Mandatory

The Value of the XYArrayItem contains an array of structures (XVType) where each structure specifies the position for the X-Axis (XVType.x) and the value itself (XVType.value), used for the Y-Axis. Engineering units and range for the Value are defined by corresponding Properties inherited from the ArrayItemType.

XAxisDefinition Property holds the information about the Engineering Units and Range for the X-Axis.

The axisSteps of XAxisDefinition shall be set to NULL because it is not used.

The StatusCode SemanticsChanged bit shall be set if any of the InstrumentRange, EURange, EngineeringUnits, Title or XAxisDefinition Properties are changed (see 5.2 for additional information).