The ScaleDeviceType defines the structure of an Object of the ScaleDeviceType. Figure 16 shows the hierarchical structure and details of the composition. It is formally defined in Table 20.

The ScaleDeviceType is an abstract ObjectType. An Object of a subtype of the ScaleDeviceType represents a scale. The ScaleDeviceType contains all information that is relevant for most of the scale types. The system is modeled with a finite state machine and contains primary information about the state and the status of the system.

image028.png

Figure 16 - Overview ScaleDeviceType

Table 20 - ScaleDeviceType Definition

Attribute

Value

BrowseName

ScaleDeviceType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the ComponentType defined in OPC 10000-100

0:HasProperty

Variable

AllowedEngineeringUnits

0:EUInformation[]

0:PropertyType

Optional

0:HasComponent

Method

ClearTare

Optional

0:HasComponent

Variable

CurrentWeight

WeightType

WeightItemType

Mandatory

0:HasComponent

Object

<ListOfWeighingRanges>

WeighingRangeElementType

MandatoryPlaceholder

0:HasProperty

Variable

MaterialClass

0:LocalizedText

0:PropertyType

Optional

0:HasComponent

Variable

MinimalWeight

0:Number

0:AnalogUnitType

Optional

0:HasProperty

Variable

ProcessStateId

0:String

0:PropertyType

Optional

0:HasProperty

Variable

ProcessStateMessage

0:LocalizedText

0:PropertyType

Optional

0:HasComponent

Object

ProductionOutput

StatisticType

Optional

0:HasComponent

Object

ProductionPreset

ProductionPresetType

Optional

0:HasProperty

Variable

Policy

0:LocalizedText[]

0:PropertyType

Optional

0:HasComponent

Variable

RegisteredWeight

WeightType

WeightItemType

Optional

0:HasComponent

Method

RegisterWeight

Optional

0:HasComponent

Method

SetPresetTare

Optional

0:HasComponent

Method

SetTare

Optional

0:HasComponent

Method

SetZero

Optional

0:HasComponent

Object

SubDevices

2:ConfigurableObjectType

Optional

0:HasComponent

Object

State

5:PackMLBaseStateMachineType

Optional

0:HasAddIn

Object

4:MachineryItemState

4:MachineryItemState_StateMachineType

Optional

0:HasAddIn

Object

4:MachineryOperationMode

4:MachineryOperationModeStateMachineType

Optional

0:HasComponent

Object

4:Machinery BuildingBlocks

0:FolderType

Optional

0:HasAddIn

Object

2:Identification

4:MachineIdentificationType

Mandatory

Conformance Units

Scales ScaleDeviceType

The components of the ScaleDeviceType have additional references which are defined in Table 21.

Table 21 - ScaleDeviceType Additional References

SourceBrowsePath

Reference Type

Is Forward

TargetBrowsePath

4:MachineryBuildingBlocks

0:HasAddIn

True

4:MachineryItemState

4:MachineryBuildingBlocks

0:HasAddIn

True

4:MachineryOperationMode

AllowedEngineeringUnits contains an array of engineering units that can be handled by the OPC UA server. A server that supports a method with the input argument EUInformation must also provide this array.

CurrentWeight defines the current value that is measured at the sensor at the current timestamp. This might be a highly fluctuating value.

MaterialClass defines the allowed material the scale may measure. It is only relevant for certain scales (e.g., totalizing hopper scale or continuous scale).

The MinimalWeight is the smallest sample quantity required for a weighment to just achieve a specified relative accuracy of weighing (see also EURAMET Calibration Guide No. 18). So it is the smallest load or component of a recipe that may be weighed on the scale. SubDevices: the modules (subdevices) of a modular scale are aggregated in the SubDevices Object. See OPC Unified Architecture for Devices for more information.

ProcessStateId contains a relating identification for the occurring ProcessStateMessage.

ProcessStateMessage contains the message of the current overall state of the scale.

ProductionOutput defines the statistic for the scale prodution related to this ScaleDeviceType instance.

ProductionPreset contains the production presets. See section 7.7 for the complete definition of the ProductionPresetType.

RegisteredWeight defines the last valid measurement that was recorded and will be used for further processing.

<ListOfWeighingRanges> defines the weighing range and resolution the scale may operate in with a structure of range and resolution.

Policy defines the legal guidelines that apply for the scale or need to be complied by the scale.

ScaleStateMachine provides information about the current state of the scale system and methods for controlling it. PackMLBaseStateMachineType is defined in OPC 30050.

MachineryItemState is used as defined in OPC 40001-1. Shall also be referenced as AddIn in the MachineryBuildingBlocks Folder

MachineryOperationMode is used as defined in OPC 40001-1. Shall also be referenced as AddIn in the MachineryBuildingBlocks Folder

MachineryBuildingBlocks is used as described in OPC 40001-1.

The components of the ScaleDeviceType have additional subcomponents which are defined in Table 22.

Table 22 - ScaleDeviceType Additional Subcomponents

BrowsePath

References

NodeClass

BrowseName

DataType

TypeDefinition

Others

SubDevices

0:HasComponent

Object

<FeederModule>

FeederModuleType

OptionalPlaceholder

SubDevices

0:HasComponent

Object

<PrinterModule>

PrinterModuleType

OptionalPlaceholder

SubDevices

0:HasComponent

Object

<WeighingModule>

WeighingModuleType

OptionalPlaceholder

The tare value is set to zero or deleted.

Signature

ClearTare(

);

Triggers the registration of a measured value and a new value for the RegisteredWeight will be calculated.

Signature

RegisterWeight(

);

The method set the current PresetTare.

Signature

SetPresetTare(

[in]Double PresetTare

[in]EUInformation EngineeringUnits);

Table 23 - SetPresetTare Method Arguments

Argument

Description

PresetTare

The value which should be set as tare value.

EngineeringUnits

The unit of the preset. The server must check the unit.

Table 24 - SetPresetTare Method AddressSpace definition

Attribute

Value

BrowseName

SetPresetTare

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

0:HasProperty

Variable

InputArguments

Argument[]

0:PropertyType

Mandatory

The method sets zero point. It uses the gross value of the CurrentWeight value.

Signature

SetZero (

);

The method triggers the tare operation. The CurrentWeight value is used as the tare.

Signature

SetTare(

);