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 18.

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.

image029.png

Figure 16 – Overview ScaleDeviceType

Table 18 – ScaleDeviceType Definition

Attribute

Value

BrowseName

ScaleDeviceType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

Subtype of the ComponentType defined in OPC 10000-100

0:HasProperty

Variable

AllowedEngineeringUnits

0:EUInformation[]

0:PropertyType

O

0:HasComponent

Method

ClearTare

O

0:HasComponent

Variable

CurrentWeight

WeightType

WeightItemType

M

0:HasComponent

Object

ListOfWeighingRanges

WeighingRangeElementType

MP

0:HasProperty

Variable

MaterialClass

0:LocalizedText

0:PropertyType

O

0:HasProperty

Variable

ProcessStateId

0:String

0:PropertyType

O

0:HasProperty

Variable

ProcessStateMessage

0:LocalizedText

0:PropertyType

O

0:HasComponent

Object

ProductionPreset

ProductionPresetType

O

0:HasComponent

Variable

RegisteredWeight

WeightType

WeightItemType

O

0:HasComponent

Method

RegisterWeight

O

0:HasComponent

Method

SetPresetTare

O

0:HasComponent

Method

SetTare

O

0:HasComponent

Method

SetZero

O

0:HasComponent

Object

SubDevices

2:ConfigurableObjectType

O

The following nodes are override from ComponentType and the Modelling Rule change to Mandatory

0:HasProperty

Variable

2:DeviceClass

0:PropertyType

M

0:HasProperty

Variable

2:HardwareRevision

0:PropertyType

M

0:HasProperty

Variable

2:Manufacturer

0:PropertyType

M

0:HasProperty

Variable

2:Model

0:PropertyType

M

0:HasProperty

Variable

2:SerialNumber

0:PropertyType

M

0:HasProperty

Variable

2:SoftwareRevision

0:PropertyType

M

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).

SubDevices: the modules (subdevices) of a modular scale are aggregated in the SubDevices Object . See OPC Unified Architecture for Device for more information.

ProcessStateId contains an relating identification for the occurring ProcessStateMessage.

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

ProductionPreset contains the production presets. See section 8.7 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.

The components of the ScaleDeviceType have additional references which are defined in Table 19.

Table 19 – ScaleDeviceType Additional Subcomponents

Source Path

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]EUInformationEngineeringUnits);

Table 20 – 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 21 – 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(

);