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 8.

Table 8 – 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

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.

image006.png

Figure 3 – Graphical view of a YArrayItem

Table 9 describes the values of each element presented in Figure 3.

Table 9 YArrayItem item description

Attribute / Property

Item value

Description

Magnitude Response (dB)

axisScaleType

AxisScaleEnumeration.LINEAR_0

InstrumentRange.low

-90

InstrumentRange.high

5

EURange.low

-90

EURange.high

2

EngineeringUnits.namespaceUrl

http://www.opcfoundation.org/UA/units/un/cefact

EngineeringUnits.unitId

2N

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

kHz

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_0

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