Conditionsare used in specific application domains like Maintenance, System or Process. The ConditionClasshierarchy is used to specify domains and is orthogonal to the ConditionTypehierarchy. The ConditionClassId Propertyof the ConditionTypeis used to assign a Conditionto a ConditionClass. Clientscan use this Propertyto filter out essential classes. OPC UA defines the base ObjectTypefor all ConditionClassesand a set of common classes used across many industries. Figure 21informally describes the hierarchy of ConditionClass Typesdefined in this standard.

image024.png

Figure 21– ConditionClass type hierarchy

ConditionClassesare not representations of Objects in the underlying system and, therefore, only exist as Type Nodesin the Address Space.

BaseConditionClassTypeis used as class whenever a Conditioncannot be assigned to a more concrete class. Serversshould use a more specific ConditionClass, if possible. All ConditionClass Typesderive from BaseConditionClassType. It is formally defined in Table 79.

Table 79– BaseConditionClassType definition

Attribute

Value

BrowseName

BaseConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseObjectType defined in OPC 10000-5.

The ProcessConditionClassTypeis used to classify Conditionsrelated to the process itself. Examples of a process would be a control system in a boiler or the instrumentation associated with a chemical plant or paper machine. The ProcessConditionClassTypeis formally defined in Table 80.

Table 80– ProcessConditionClassType definition

Attribute

Value

BrowseName

ProcessConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassType defined in clause 5.9.2.

The MaintenanceConditionClassTypeis used to classify Conditionsrelated to maintenance. Examples of maintenance would be Asset Management systems or conditions, which occur in process control systems, which are related to calibration of equipment. The MaintenanceConditionClassTypeis formally defined in Table 81. No further definition is provided here. It is expected that other standards groups will define domain-specific sub-types.

Table 81– MaintenanceConditionClassType definition

Attribute

Value

BrowseName

MaintenanceConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassType defined in clause 5.9.2.

The SystemConditionClassTypeis used to classify Conditionsrelated to the System. It is formally defined in Table 82. System Conditionsoccur in the controlling or monitoring system process. Examples of System related items could include available disk space on a computer, Archive media availability, network loading issues or a controller error, No further definition is provided here. It is expected that other standards groups or vendors will define domain-specific sub-types.

Table 82– SystemConditionClassType definition

Attribute

Value

BrowseName

SystemConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause 5.9.2.

The SafetyConditionClassTypeis used to classify Conditionsrelated to safety. It is formally defined in Table 82.

Safety Conditionsoccur in the controlling or monitoring system process. Examples of safety related items could include, emergency shutdown systems or fire suppression systems.

Table 83– SafetyConditionClassType definition

Attribute

Value

BrowseName

SafetyConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause 5.9.2.

In Alarmsystems some Alarmsmay be classified as highly managed Alarms. This class of Alarmrequires special handling that varies according to the individual requirements. It might require individual acknowledgement or not allow suppression or any of a number of other special behaviours. The HighlyManagedAlarmConditionClassTypeis used to classify Conditionsas highly managed Alarms. It is formally defined in Table 84.

Table 84– HighlyManagedAlarmConditionClassType definition

Attribute

Value

BrowseName

HighlyManagedAlarmConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause 5.9.2.

The TrainingConditionClassTypeis used to classify Conditionsrelated to training system or training exercises. It is formally defined in Table 85. These Conditionstypically occur in a training system or are generated as part of a simulation for a training exercise. Training Conditionsmight be process or system conditions. It is expected that other standards groups or vendors will define domain-specific sub-types.

Table 85– TrainingConditionClassType definition

Attribute

Value

BrowseName

TrainingConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause.

The StatisticalConditionClassTypeis used to classify Conditionsrelated that are based on statistical calculations. It is formally defined in Table 86. These Conditionsare generated as part of a statistical analysis. They might be any of an Alarmnumber of types.

Table 86– StatisticalConditionClassType definition

Attribute

Value

BrowseName

StatisticalConditionClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause.

The TestingConditionSubClassTypeis used to classify Conditionsrelated to testing of an Alarmsystem or Alarmfunction. It is formally defined in Table 87. Testing Conditionsmight include a condition to test an alarm annunciation such as a horn or other panel. It might also be used to temporarily reclassify a Conditionto check response times or suppression logic. It is expected that other standards groups or vendors will define domain-specific sub-types.

Table 87– TestingConditionSubClassType definition

Attribute

Value

BrowseName

TestingConditionSubClassType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

Subtype of the BaseConditionClassTypedefined in clause 5.9.2.