The VariableType defines the general characteristics of a TargetItem. A TargetItem is a OPC UA Variable that represents a target value. It is formally defined in Table 136.

image082.gif

Figure 67 − Overview TargetItemType

Table 136 − TargetItemType Definition

Attribute

Value

BrowseName

TargetItemType

IsAbstract

False

ValueRank

-2

DataType

0:Number

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the 0:AnalogItemType

0:HasComponent

Variable

MinusTolerance

0:Number

0:AnalogItemType

Optional

0:HasComponent

Variable

PlusTolerance

0:Number

0:AnalogItemType

Optional

0:HasProperty

Variable

AllowedEngineeringUnits

0:EUInformation[]

0:PropertyType

Optional

MinusTolerance contains the lower relative limit of the value in TargetItemType. This may be a percentage or a relative concrete value.

PlusTolerance contains the upper relative limit of the value in TargetItemType. This may be a percentage or a relative concrete value.

AllowedEngineeringUnits contains an array of engineering units that can be handled by the OPC UA server.

The VariableType defines the general characteristics of a MeasuredItem. A MeasuredItem is an OPC UA Variable that represents a measured value. It adds some Properties that describe the measurement parameters. It is formally defined in Table 137 and is leaned to the 0:AnalogItemType from OPC 10000-8.

image083.gif

Figure 68 − Overview MeasuredItemType

Table 137 − MeasuredItemType Definition

Attribute

Value

BrowseName

MeasuredItemType

IsAbstract

False

ValueRank

-2

DataType

BaseDataType

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the DataItemType

0:HasProperty

Variable

0:EngineeringUnits

0:EUInformation

0:PropertyType

Mandatory

0:HasProperty

Variable

0:EURange

0:Range

0:PropertyType

Mandatory

0:HasProperty

Variable

0:InstrumentRange

0:Range

0:PropertyType

Optional

EngineeringUnits specifies the units for the DataItems value (e.g. DEGC, hertz, seconds). The 0:EUInformation type is specified in OPC 10000-8. If the DataType is a WeightItemType or a PrintableWeightItemType it is the unit of net, gross and tare.

EURange is specified like the EURange of the 0:AnalogItemType in OPC 10000-8. If the DataType is a WeightItemType or a PrintableWeightItemType it is the range of net, gross and tare.

InstrumentRange is specified like the EURange of the 0:AnalogItemType in OPC 10000-8.

The VariableType defines the general characteristics of a WeightItem. The WeightItem is a measured weight value with some Properties. The value attribute has the DataType AbstractWeightType (see section 0) and contains the value of net, gross and tare. It is formally defined in Table 138.

The value of the WeightItemType is rounded to a verification scale division value if the scale is verified, otherwise it is rounded to the scale division.

image084.gif

Figure 69 − Overview WeightItemType

Table 138 − WeightItemType Definition

Attribute

Value

BrowseName

WeightItemType

IsAbstract

False

ValueRank

-1

DataType

WeightType

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the MeasuredItemType

0:HasProperty

Variable

CenterOfZero

0:Boolean

0:PropertyType

Optional

0:HasProperty

Variable

CurrentRangeId

0:UInt16

0:PropertyType

Optional

0:HasProperty

Variable

GrossNegative

0:Boolean

0:PropertyType

Optional

0:HasProperty

Variable

HighResolutionValue

WeightType

0:PropertyType

Optional

0:HasProperty

Variable

InsideZero

0:Boolean

0:PropertyType

Optional

0:HasProperty

Variable

LegalForTrade

0:Boolean

0:PropertyType

Optional

0:HasProperty

Variable

Overload

0:Boolean

0:PropertyType

Mandatory

0:HasProperty

Variable

PrintableValue

PrintableWeightType

0:PropertyType

Optional

0:HasProperty

Variable

TareMode

TareMode

0:PropertyType

Mandatory

0:HasProperty

Variable

Underload

0:Boolean

0:PropertyType

Mandatory

0:HasProperty

Variable

WeightId

0:String

0:PropertyType

Optional

0:HasProperty

Variable

WeightStable

0:Boolean

0:PropertyType

Optional

0:HasProperty

Variable

Net

0:Double

0:PropertyType

Optional

0:HasProperty

Variable

Gross

0:Double

0:PropertyType

Optional

0:HasProperty

Variable

Tare

0:Double

0:PropertyType

Optional

CenterOfZero defines if a value is in the vendor-specific tolerance to be zero (e.g., value differs by signal noise).

GrossNegative defines if the gross value is negative (e.g., in case of a too high preload).

HighResolutionValue defines the measured value. It is the best resolution the scale can provide in the current configuration.

InsideZero defines if the current measured value is within the valid range for the zero-setting procedure. If this variable is true, the setZero method can be called successfully if the Property does not change.

LegalForTrade defines if the current measured value is legal for trade.

Overload defines if the maximum allowed measured weight value is exceeded.

PrintableValue defines the measured value as 0:String representation without a unit. It is also rounded.

TareMode describes how the tare value is set.

Underload defines if the measued weight falls below the minimum allowed measured weight value.

WeightId defines a unique ID that refers to the verified value of a measurement procedure.

WeightStable defines if the weight is stable and not in movement.

Gross defines the gross value of weight as a 0:Double precision floating point number.

Net defines the net value of weight as a 0:Double precision floating point number.

Tare defines the tare value of weight as a 0:Double precision floating point number.

Gross, Net, Tare h ave the same semantics as defined in 0.