YArrayItemType represents a single-dimensional array of numerical values used to represent spectra or distributions where the x axis intervals are constant. YArrayItemType is formally defined in Table 11.

Table 11 – YArrayItemType definition

Attribute	Value
BrowseName	YArrayItemType
IsAbstract	False
ValueRank	1
DataType	BaseDataType
ArrayDimensions	{0} (0 = UnknownSize)
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the ArrayItemType defined in 5.3.4.1
HasProperty	Variable	XAxisDefinition	AxisInformation	PropertyType	Mandatory
Conformance Units
Data Access YArrayItemType

The Value of the YArrayItem contains the numerical values for the Y-Axis. Engineering Units and Range for the Value are defined by corresponding Properties inherited from the ArrayItemType.

The DataType of this VariableType is restricted to SByte, Int16, Int32, Int64, Float, Double, ComplexNumberType and DoubleComplexNumberType.

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

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

Figure 3 shows an example of how Attributes and Properties may be used in a graphical interface.

Figure 3 – Graphical view of a YArrayItem

Table 12 describes the values of each element presented in Figure 3.

Table 12 – YArrayItem item description

Attribute / Property	Item value
Description	Magnitude Response (dB)
axisScaleType	AxisScaleEnumeration.LINEAR
InstrumentRange.low	-90
InstrumentRange.high	5
EURange.low	-90
EURange.high	2
EngineeringUnits.namespaceUrl	http://www.opcfoundation.org/UA/units/un/cefact
EngineeringUnits.unitId	12878
EngineeringUnits.displayName	“en-us”, “dB”
EngineeringUnits.description	“en-us”, “decibel”
Title	Magnitude
XAxisDefinition.EngineeringUnits.namespaceUrl	http://www.opcfoundation.org/UA/units/un/cefact
XAxisDefinition.EngineeringUnits.unitId	4933722
XAxisDefinition.EngineeringUnits.displayName	“en-us”, “kHz”
XAxisDefinition.EngineeringUnits.description	“en-us”, “kilohertz”
XAxisDefinition.Range.low	0
XAxisDefinition.Range.high	25
XAxisDefinition.title	“en-us”, “Frequency”
XAxisDefinition.axisScaleType	AxisScaleEnumeration.LINEAR
XAxisDefinition.axisSteps	null

Interpretation notes:

• Not all elements of this table are used in the graphic.
• The X axis is displayed in reverse order, however, the XAxisDefinition.Range.low shall be lower than XAxisDefinition.Range.high. It is only a graphical representation that reverses the display order.
• There is a constant X axis