9 OPC UA VariableTypes

9.1 TargetItemType

9.1.1 Overview

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 141.

9.1.2 TargetItemType Definition

9.1.3 TargetItemType Description

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.

9.2 MeasuredItemType

9.2.1 Overview

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 142 and is leaned to the 0:AnalogItemType from OPC 10000-8.

9.2.2 MeasuredItemType Definition

9.2.3 MeasuredItemType Description

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.

9.3 WeightItemType

9.3.1 Overview

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 10.1) and contains the value of net, gross and tare. It is formally defined in Table 143.

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.

9.3.2 WeightItemType Definition

9.3.3 WeightItemType Description

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

CurrentRangeId describes the identifier of the current range.

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.