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 23informally describes the hierarchy of ConditionClass Typesdefined in this standard.

Figure 23– 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 113.

Table 113– BaseConditionClassType definition

Attribute	Value
BrowseName	BaseConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseObjectType defined in 10000-5.
ConformanceUnits
A & C ConditionClasses

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 114.

Table 114– ProcessConditionClassType definition

Attribute	Value
BrowseName	ProcessConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassType defined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses

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 115. No further definition is provided here. It is expected that other standards groups will define domain-specific sub-types.

Table 115– MaintenanceConditionClassType definition

Attribute	Value
BrowseName	MaintenanceConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassType defined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses

The SystemConditionClassTypeis used to classify Conditionsrelated to the System. It is formally defined in Table 116. 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. It is expected that other standards groups or vendors will define domain-specific sub-types.

Table 116– SystemConditionClassType definition

Attribute	Value
BrowseName	SystemConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses

The SafetyConditionClassTypeis used to classify Conditionsrelated to safety. It is formally defined in Table 117.

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

Table 117– SafetyConditionClassType definition

Attribute	Value
BrowseName	SafetyConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses

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 118.

Table 118– HighlyManagedAlarmConditionClassType definition

Attribute	Value
BrowseName	HighlyManagedAlarmConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses

The TrainingConditionClassTypeis used to classify Conditionsrelated to training system or training exercises. It is formally defined in Table 119. 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 119– TrainingConditionClassType definition

Attribute	Value
BrowseName	TrainingConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause.
ConformanceUnits
A & C ConditionClasses

The StatisticalConditionClassTypeis used to classify Conditionsrelated that are based on statistical calculations. It is formally defined in Table 120. These Conditionsare generated as part of a statistical analysis. They might be any of an Alarmnumber of types.

Table 120– StatisticalConditionClassType definition

Attribute	Value
BrowseName	StatisticalConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause.
ConformanceUnits
A & C ConditionClasses

The TestingConditionClassTypeis used to classify Conditionsrelated to testing of an Alarmsystem or Alarmfunction. It is formally defined in Table 121. 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 121– TestingConditionClassType definition

Attribute	Value
BrowseName	TestingConditionClassType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseConditionClassTypedefined in clause 5.9.2.
ConformanceUnits
A & C ConditionClasses