5 Model ToC Previous Next

5.3 Variable Types ToC Previous Next

5.3.4 ArrayItemType ToC Previous Next

5.3.4.1 General ToC Model

This abstract VariableType defines the general characteristics of an ArrayItem. Values are exposed in an array but the content of the array represents a single entity like an image. Other DataItems might contain arrays that represent for example several values of several temperature sensors of a boiler.

ArrayItemType or its subtype shall only be used when the Title and AxisScaleType Properties can be filled with reasonable values. If this is not the case DataItemType and subtypes like AnalogItemType, which also support arrays, shall be used. The ArrayItemType is formally defined in Table 7.

Table 7 – ArrayItemType definition

Attribute Value
BrowseName ArrayItemType
IsAbstract True
ValueRank 0 (0 = OneOrMoreDimensions)
DataType BaseDataType

Subtype of the DataItemType defined in 5.3.1; i.e the Properties of that type are inherited.

References NodeClass BrowseName DataType TypeDefinition ModellingRule
HasSubtype VariableType YArrayItemType Defined in 5.3.4.2    
HasSubtype VariableType XYArrayItemType Defined in 5.3.4.3    
HasSubtype VariableType ImageItemType Defined in 5.3.4.4    
HasSubtype VariableType CubeItemType Defined in 5.3.4.5    
HasSubtype VariableType NDimensionArrayItemType Defined in 5.3.4.6    
HasProperty Variable InstrumentRange Range PropertyType Optional
HasProperty Variable EURange Range PropertyType Mandatory
HasProperty Variable EngineeringUnits EUInformation PropertyType Mandatory
HasProperty Variable Title LocalizedText PropertyType Mandatory
HasProperty Variable AxisScaleType AxisScaleEnumeration PropertyType Mandatory

InstrumentRange defines the range of the Value of the ArrayItem.

EURange defines the value range of the ArrayItem likely to be obtained in normal operation. It is intended for such use as automatically scaling a bar graph display.

EngineeringUnits holds the information about the engineering units of the Value of the ArrayItem.

For additional information about InstrumentRange, EURange, and EngineeringUnits see the description of AnalogItemType in 0.

Title holds the user readable title of the Value of the ArrayItem.

AxisScaleType defines the scale to be used for the axis where the Value of the ArrayItem shall be displayed.

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

5.3.4.2 YArrayItemType ToC Model

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)

Subtype of the ArrayItemType defined in 5.3.4.1

References NodeClass BrowseName DataType TypeDefinition ModellingRule
           
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.

readme_files/image005.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

    5.3.4.3 XYArrayItemType ToC Model

    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

Subtype of the ArrayItemType defined in 5.3.4.1

References NodeClass BrowseName DataType TypeDefinition ModellingRule
           
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).

5.3.4.4 ImageItemType ToC Model

ImageItemType defines the general characteristics of an ImageItem which represents a matrix of values like an image, where the pixel position is given by X which is the column and Y the row. The value is the pixel intensity.

ImageItemType is formally defined in Table 11.

Table 11 – ImageItemType definition

Attribute Value
BrowseName ImageItemType
IsAbstract False
ValueRank 2 (2 = two dimensional array)
DataType BaseDataType

Subtype of the ArrayItemType defined in 5.3.4.1

References NodeClass BrowseName DataType TypeDefinition ModellingRule
           
HasProperty Variable XAxisDefinition AxisInformation PropertyType Mandatory
HasProperty Variable YAxisDefinition AxisInformation PropertyType Mandatory

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 ArrayDimensions Attribute for Variables of this type or subtypes shall use the first entry in the array ([0]) to define the number of columns and the second entry ([1]) to define the number of rows, assuming the size of the matrix is not dynamic.

XAxisDefinition Property holds the information about the engineering units and range for the X-Axis.

YAxisDefinition Property holds the information about the engineering units and range for the Y-Axis.

The StatusCode.SemanticsChanged bit shall be set if any of the InstrumentRange, EURange, EngineeringUnits, Title, XAxisDefinition or YAxisDefinition Properties are changed.

5.3.4.5 CubeItemType ToC Model

CubeItemType represents a cube of values like a spatial particle distribution, where the particle position is given by X which is the column, Y the row and Z the depth. In the example of a spatial partical distribution, the value is the particle size. CubeItemType is formally defined in Table 12.

Table 12 – CubeItemType definition

Attribute Value
BrowseName CubeItemType
IsAbstract False
ValueRank 3 (3 = three dimensional array)
DataType BaseDataType

Subtype of the ArrayItemType defined in 5.3.4.1

References NodeClass BrowseName DataType TypeDefinition ModellingRule
           
HasProperty Variable XAxisDefinition AxisInformation PropertyType Mandatory
HasProperty Variable YAxisDefinition AxisInformation PropertyType Mandatory
HasProperty Variable ZAxisDefinition AxisInformation PropertyType Mandatory

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 ArrayDimensions Attribute for Variables of this type or subtypes should use the first entry in the array ([0]) to define the number of columns, the second entry ([1]) to define the number of rows, and the third entry ([2]) define the number of steps in the Z axis, assuming the size of the matrix is not dynamic.

XAxisDefinition Property holds the information about the engineering units and range for the X-Axis.

YAxisDefinition Property holds the information about the engineering units and range for the Y-Axis.

ZAxisDefinition Property holds the information about the engineering units and range for the Z-Axis.

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

5.3.4.6 NDimensionArrayItemType ToC Model

This VariableType defines a generic multi-dimensional ArrayItem.

This approach minimizes the number of types however it may be proved more difficult to utilize for control system interactions.

NDimensionArrayItemType is formally defined in Table 13.

Table 13 – NDimensionArrayItemType definition

Attribute Value
BrowseName NDimensionArrayItemType
IsAbstract False
ValueRank 0 (0 = OneOrMoreDimensions)
DataType BaseDataType

Subtype of the ArrayItemType defined in 5.3.4.1

References NodeClass BrowseName DataType TypeDefinition ModellingRule
           
HasProperty Variable AxisDefinition AxisInformation [] PropertyType Mandatory

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

AxisDefinition Property holds the information about the Engineering Units and Range for all axis.

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

Previous Next