UA Part 5: Information Model - 12 Standard DataTypes

An OPC UA Server need not expose its DataTypes in its AddressSpace. Independent of the exposition of DataTypes, it shall support the DataTypes as described in the following subclauses.

12.2 DataTypes defined in OPC 10000-3

OPC 10000-3 defines a set of DataTypes. Their representation in the AddressSpace is defined in Table 115.

Table 115 – OPC 10000-3 DataType Definitions

BrowseName
Argument
AudioDataType
BaseDataType
Boolean
Byte
ByteString
DataTypeDefinition
DateString
DateTime
Decimal
DecimalString
Double
Duration
DurationString
EnumDefinition
Enumeration
EnumField
EnumValueType
Float
Guid
IdType
Image
ImageBMP
ImageGIF
ImageJPG
ImagePNG
Int16
Int32
Int64
Integer
LocaleId
LocalizedText
NamingRuleType
NodeClass
NodeId
NormalizedString
Number
OptionSet
QualifiedName
SByte
String
Structure
StructureDefinition
StructureField
TimeString
TimeZoneDataType
UInt16
UInt32
UInt64
UInteger
Union
UtcTime
XmlElement

Of the DataTypes defined in Table 115 only some are the sources of References as defined in the following tables.

The References of the BaseDataType are defined in Table 116.

Table 116 – BaseDataType Definition

Attributes	Value
BrowseName	BaseDataType
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Boolean	FALSE
HasSubtype	DataType	ByteString	FALSE
HasSubtype	DataType	DateTime	FALSE
HasSubtype	DataType	DataValue	FALSE
HasSubtype	DataType	DiagnosticInfo	FALSE
HasSubtype	DataType	Enumeration	TRUE
HasSubtype	DataType	ExpandedNodeId	FALSE
HasSubtype	DataType	Guid	FALSE
HasSubtype	DataType	LocalizedText	FALSE
HasSubtype	DataType	NodeId	FALSE
HasSubtype	DataType	Number	TRUE
HasSubtype	DataType	QualifiedName	FALSE
HasSubtype	DataType	String	FALSE
HasSubtype	DataType	Structure	TRUE
HasSubtype	DataType	XmlElement	FALSE

The References of Structure are defined in Table 117.

Table 117 – Structure Definition

Attributes	Value
BrowseName	Structure
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Argument	FALSE
HasSubtype	DataType	UserIdentityToken	TRUE
HasSubtype	DataType	AddNodesItem	FALSE
HasSubtype	DataType	AddReferencesItem	FALSE
HasSubtype	DataType	DeleteNodesItem	FALSE
HasSubtype	DataType	DeleteReferencesItem	FALSE
HasSubtype	DataType	ApplicationDescription	FALSE
HasSubtype	DataType	BuildInfo	FALSE
HasSubtype	DataType	RedundantServerDataType	FALSE
HasSubtype	DataType	SamplingIntervalDiagnosticsDataType	FALSE
HasSubtype	DataType	ServerDiagnosticsSummaryDataType	FALSE
HasSubtype	DataType	ServerStatusDataType	FALSE
HasSubtype	DataType	SessionDiagnosticsDataType	FALSE
HasSubtype	DataType	SessionSecurityDiagnosticsDataType	FALSE
HasSubtype	DataType	ServiceCounterDataType	FALSE
HasSubtype	DataType	StatusResult	FALSE
HasSubtype	DataType	SubscriptionDiagnosticsDataType	FALSE
HasSubtype	DataType	ModelChangeStructureDataType	FALSE
HasSubtype	DataType	SemanticChangeStructureDataType	FALSE
HasSubtype	DataType	SignedSoftwareCertificate	FALSE
HasSubtype	DataType	TimeZoneDataType	FALSE
HasSubtype	DataType	EnumValueType	FALSE
HasSubtype	DataType	OptionSet	TRUE
HasSubtype	DataType	Union	TRUE
HasSubtype	DataType	StructureField	FALSE
HasSubtype	DataType	DataTypeDefinition	TRUE

The References of Enumeration are defined in Table 118.

Table 118 – Enumeration Definition

Attributes	Value
BrowseName	Enumeration
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	IdType	FALSE
HasSubtype	DataType	NamingRuleType	FALSE
HasSubtype	DataType	NodeClass	FALSE
HasSubtype	DataType	SecurityTokenRequestType	FALSE
HasSubtype	DataType	MessageSecurityMode	FALSE
HasSubtype	DataType	RedundancySupport	FALSE
HasSubtype	DataType	ServerState	FALSE

The References of ByteString are defined in Table 119.

Table 119 – ByteString Definition

Attributes	Value
BrowseName	ByteString
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Image	TRUE
HasSubtype	DataType	AudioDataType	FALSE

The References of Number are defined in Table 120.

Table 120 – Number Definition

Attributes	Value
BrowseName	Number
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Integer	TRUE
HasSubtype	DataType	UInteger	TRUE
HasSubtype	DataType	Double	FALSE
HasSubtype	DataType	Float	FALSE
HasSubtype	DataType	Decimal	FALSE

The References of Double are defined in Table 121.

Table 121 – Double Definition

Attributes	Value
BrowseName	Double
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Duration	FALSE

The References of Integer are defined in Table 122.

Table 122 – Integer Definition

Attributes	Value
BrowseName	Integer
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	SByte	FALSE
HasSubtype	DataType	Int16	FALSE
HasSubtype	DataType	Int32	FALSE
HasSubtype	DataType	Int64	FALSE

The References of DateTime are defined in Table 123.

Table 123 – DateTime Definition

Attributes	Value
BrowseName	DateTime
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	UtcTime	FALSE

The References of String are defined in Table 124.

Table 124 – String Definition

Attributes	Value
BrowseName	String
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	LocaleId	FALSE
HasSubtype	DataType	NumericRange	FALSE
HasSubtype	DataType	NormalizedString	FALSE
HasSubtype	DataType	DecimalString	FALSE
HasSubtype	DataType	DurationString	FALSE
HasSubtype	DataType	TimeString	FALSE
HasSubtype	DataType	DateString	FALSE

The References of UInteger are defined in Table 125.

Table 125 – UInteger Definition

Attributes	Value
BrowseName	UInteger
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	Byte	FALSE
HasSubtype	DataType	UInt16	FALSE
HasSubtype	DataType	UInt32	FALSE
HasSubtype	DataType	UInt64	FALSE

The References of Image are defined in Table 126.

Table 126 – Image Definition

Attributes	Value
BrowseName	Image
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	ImageBMP	FALSE
HasSubtype	DataType	ImageGIF	FALSE
HasSubtype	DataType	ImageJPG	FALSE
HasSubtype	DataType	ImagePNG	FALSE

The References of UInt64 are defined in Table 127.

Table 127 – UInt64 Definition

Attributes	Value
BrowseName	UInt64
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	BitFieldMaskDataType	FALSE

The References of DataTypeDefinition are defined in Table 128.

Table 128 – DataTypeDefinition Definition

Attributes	Value
BrowseName	DataTypeDefinition
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	StructureDefinition	FALSE
HasSubtype	DataType	EnumDefinition	FALSE

The References of EnumValueType are defined in Table 129.

Table 129 – EnumValueType Definition

Attributes	Value
BrowseName	EnumValueType
IsAbstract	FALSE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	EnumField	FALSE

12.3 DataTypes defined in OPC 10000-4

OPC 10000-4 defines a set of DataTypes. Their representation in the AddressSpace is defined in Table 130.

Table 130 – OPC 10000-4 DataType Definitions

BrowseName
AnonymousIdentityToken
DataValue
DiagnosticInfo
ExpandedNodeId
SignedSoftwareCertificate
UserIdentityToken
UserNameIdentityToken
X509IdentityToken
SecurityTokenRequestType
AddNodesItem
AddReferencesItem
DeleteNodesItem
DeleteReferencesItem
NumericRange
MessageSecurityMode
ApplicationDescription

The SecurityTokenRequestType is an enumeration that is defined as the type of the requestType parameter of the OpenSecureChannel Service in OPC 10000-4.

The AddNodesItem is a structure that is defined as the type of the nodesToAdd parameter of the AddNodes Service in OPC 10000-4.

The AddReferencesItem is a structure that is defined as the type of the referencesToAdd parameter of the AddReferences Service in OPC 10000-4.

The DeleteNodesItem is a structure that is defined as the type of the nodesToDelete parameter of the DeleteNodes Service in OPC 10000-4.

The DeleteReferencesItem is a structure that is defined as the type of the referencesToDelete parameter of the DeleteReferences Service in OPC 10000-4.

The References of UserIdentityToken are defined in Table 131.

Table 131 – UserIdentityToken Definition

Attributes	Value
BrowseName	UserIdentityToken
IsAbstract	TRUE
References	NodeClass	BrowseName	IsAbstract
HasSubtype	DataType	UserNameIdentityToken	FALSE
HasSubtype	DataType	X509IdentityToken	FALSE
HasSubtype	DataType	AnonymousIdentityToken	FALSE

12.4 BuildInfo

This structure contains elements that describe the build information of the Server. Its elements are defined in Table 132.

Table 132 – BuildInfo Structure

Name	Type	Description
BuildInfo	structure	Information that describes the build of the software.
productUri	String	URI that identifies the software
manufacturerName	String	Name of the software manufacturer.
productName	String	Name of the software.
softwareVersion	String	Software version
buildNumber	String	Build number
buildDate	UtcTime	Date and time of the build.

Its representation in the AddressSpace is defined in Table 133.

Table 133 – BuildInfo Definition

Attributes	Value
BrowseName	BuildInfo

12.5 RedundancySupport

This DataType is an enumeration that defines the redundancy support of the Server. Its values are defined in Table 134.

Table 134 – RedundancySupport Values

Value	Description
NONE_0	None means that there is no redundancy support.
COLD_1	Cold means that the server supports cold redundancy as defined in OPC 10000-4.
WARM_2	Warm means that the server supports warm redundancy as defined in OPC 10000-4.
HOT_3	Hot means that the server supports hot redundancy as defined in OPC 10000-4.
TRANSPARENT_4	Transparent means that the server supports transparent redundancy as defined in OPC 10000-4.
HOT_AND_MIRRORED_5	HotAndMirrored means that the server supports HotAndMirrored redundancy as defined in OPC 10000-4.

See OPC 10000-4 for a more detailed description of the different values.

Its representation in the AddressSpace is defined in Table 135.

Table 135 – RedundancySupport Definition

Attribute	Value
BrowseName	RedundancySupport
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	EnumStrings	LocalizedText[]	PropertyType	Mandatory

12.6 ServerState

This DataType is an enumeration that defines the execution state of the Server. Its values are defined in Table 136.

Table 136 – ServerState Values

Value	Description
RUNNING_0	The Server is running normally. This is the usual state for a Server.
FAILED_1	A vendor-specific fatal error has occurred within the Server. The Server is no longer functioning. The recovery procedure from this situation is vendor-specific. Most Service requests should be expected to fail.
NO_CONFIGURATION_2	The Server is running but has no configuration information loaded and therefore does not transfer data.
SUSPENDED_3	The Server has been temporarily suspended by some vendor-specific method and is not receiving or sending data.
SHUTDOWN_4	The Server initiated a shut down or is in the process of shutting down. This ServerState is intended as an indication to Clients connected to the Server to orderly disconnect from the Server before the Server completes the shut down.
TEST_5	The Server is in Test Mode. The outputs are disconnected from the real hardware, but the Server will otherwise behave normally. Inputs may be real or may be simulated depending on the vendor implementation. StatusCode will generally be returned normally.
COMMUNICATION_FAULT_6	The Server is running properly, but is having difficulty accessing data from its data sources. This may be due to communication problems or some other problem preventing the underlying device, control system, etc. from returning valid data. It may be a complete failure, meaning that no data is available, or a partial failure, meaning that some data is still available. It is expected that items affected by the fault will individually return with a BAD FAILURE status code indication for the items.
UNKNOWN_7	This state is used only to indicate that the OPC UA Server does not know the state of underlying system.

Its representation in the AddressSpace is defined in Table 137.

Table 137 – ServerState Definition

Attribute	Value
BrowseName	ServerState
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
HasProperty	Variable	EnumStrings	LocalizedText[]	PropertyType	Mandatory

12.7 RedundantServerDataType

This structure contains elements that describe the status of the Server. Its composition is defined in Table 138.

Table 138 – RedundantServerDataType Structure

Name	Type	Description
RedundantServerDataType	structure
serverId	String	The Id of the server (not the URI).
serviceLevel	Byte	The service level of the server.
serverState	ServerState	The current state of the server.

Its representation in the AddressSpace is defined in Table 139.

Table 139 – RedundantServerDataType Definition

Attributes	Value
BrowseName	RedundantServerDataType

12.8 SamplingIntervalDiagnosticsDataType

This structure contains diagnostic information about the sampling rates currently used by the Server. Its elements are defined in Table 140.

Table 140 – SamplingIntervalDiagnosticsDataType Structure

Name	Type	Description
SamplingIntervalDiagnosticsDataType	structure
samplingInterval	Duration	The sampling interval in milliseconds.
monitoredItemCount	UInt32	The number of MonitoredItems being sampled at this sample rate.
maxMonitoredItemCount	UInt32	The maximum number of MonitoredItems being sampled at this sample rate at the same time since the server was started (restarted).
disabledMonitoredItemCount	UInt32	The number of MonitoredItems at this sample rate whose sampling currently disabled.

Its representation in the AddressSpace is defined in Table 141.

Table 141 – SamplingIntervalDiagnosticsDataType Definition

Attributes	Value
BrowseName	SamplingIntervalDiagnosticsDataType

12.9 ServerDiagnosticsSummaryDataType

This structure contains diagnostic summary information for the Server. Its elements are defined in Table 142.

Table 142 – ServerDiagnosticsSummaryDataType Structure

Name	Type	Description
ServerDiagnosticsSummaryDataType	structure
serverViewCount	UInt32	The number of server-created views in the server.
currentSessionCount	UInt32	The number of client sessions currently established in the server.
cumulatedSessionCount	UInt32	The cumulative number of client sessions that have been established in the server since the server was started (or restarted). This includes the currentSessionCount.
securityRejectedSessionCount	UInt32	The number of client session establishment requests (ActivateSession and CreateSession) that were rejected due to security constraints since the server was started (or restarted).
rejectedSessionCount	UInt32	The number of client session establishment requests (ActivateSession and CreateSession) that were rejected since the server was started (or restarted). This number includes the securityRejectedSessionCount.
sessionTimeoutCount	UInt32	The number of client sessions that were closed due to timeout since the server was started (or restarted).
sessionAbortCount	UInt32	The number of client sessions that were closed due to errors since the server was started (or restarted).
currentSubscriptionCount	UInt32	The number of subscriptions currently established in the server.
cumulatedSubscriptionCount	UInt32	The cumulative number of subscriptions that have been established in the server since the server was started (or restarted). This includes the currentSubscriptionCount.
publishingIntervalCount	UInt32	The number of publishing intervals currently supported in the server.
securityRejectedRequestsCount	UInt32	The number of requests that were rejected due to security constraints since the server was started (or restarted). The requests include all Services defined in OPC 10000-4, also requests to create sessions.
rejectedRequestsCount	UInt32	The number of requests that were rejected since the server was started (or restarted). The requests include all Services defined in OPC 10000-4, also requests to create sessions. This number includes the securityRejectedRequestsCount.

Its representation in the AddressSpace is defined in Table 143.

Table 143 – ServerDiagnosticsSummaryDataType Definition

Attributes	Value
BrowseName	ServerDiagnosticsSummaryDataType

12.10 ServerStatusDataType

This structure contains elements that describe the status of the Server. Its composition is defined in Table 144.

Table 144 – ServerStatusDataType Structure

Name	Type	Description
ServerStatusDataType	structure
startTime	UtcTime	Time (UTC) the Server was started. This is constant for the Server instance and is not reset when the Server changes state. Each instance of a Server should keep the time when the process started.
currentTime	UtcTime	The current time (UTC) as known by the Server.
state	ServerState	The current state of the Server. Its values are defined in 12.6.
buildInfo	BuildInfo
secondsTillShutdown	UInt32	Approximate number of seconds until the Server will be shut down. The value is only relevant once the state changes into SHUTDOWN_4. After the Server shut down is initated, the state changes to SHUTDOWN_4 and the actual shut down should be delayed for a configurable time if Clients are connected to the Server to allow these Clients an orderly disconnect.
shutdownReason	LocalizedText	An optional localized text indicating the reason for the shutdown. The value is only relevant once the state changes into SHUTDOWN_4.

Its representation in the AddressSpace is defined in Table 145.

Table 145 – ServerStatusDataType Definition

Attributes	Value
BrowseName	ServerStatusDataType

12.11 SessionDiagnosticsDataType

This structure contains diagnostic information about client sessions. Its elements are defined in Table 146. Most of the values represented in this structure provide information about the number of calls of a Service, the number of currently used MonitoredItems, etc. Those numbers need not provide the exact value; they need only provide the approximate number, so that the Server is not burdened with providing the exact numbers.

Table 146 – SessionDiagnosticsDataType Structure

Name	Type	Description
SessionDiagnosticsDataType	structure
sessionId	NodeId	Server-assigned identifier of the session.
sessionName	String	The name of the session provided in the CreateSession request.
clientDescription	Application Description	The description provided by the client in the CreateSession request.
serverUri	String	The serverUri request in the CreateSession request.
endpointUrl	String	The endpointUrl passed by the client to the CreateSession request.
localeIds	LocaleId[]	Array of LocaleIds specified by the client in the open session call.
actualSessionTimeout	Duration	The requested session timeout specified by the client in the open session call.
maxResponseMessageSize	UInt32	The maximum size for the response message sent to the client.
clientConnectionTime	UtcTime	The server timestamp when the client opens the session.
clientLastContactTime	UtcTime	The server timestamp of the last request of the client in the context of the session.
currentSubscriptionsCount	UInt32	The number of subscriptions currently used by the session.
currentMonitoredItemsCount	UInt32	The number of MonitoredItems currently used by the session
currentPublishRequestsInQueue	UInt32	The number of publish requests currently in the queue for the session.
totalRequestCount	ServiceCounterDataType	Counter of all Services, identifying the number of received requests of any Services on the session.
unauthorizedRequestCount	UInt32	Counter of all Services, identifying the number of Service requests that were rejected due to authorization failure
readCount	ServiceCounterDataType	Counter of the Read Service, identifying the number of received requests of this Service on the session.
historyReadCount	ServiceCounterDataType	Counter of the HistoryRead Service, identifying the number of received requests of this Service on the session.
writeCount	ServiceCounterDataType	Counter of the Write Service, identifying the number of received requests of this Service on the session.
historyUpdateCount	ServiceCounterDataType	Counter of the HistoryUpdate Service, identifying the number of received requests of this Service on the session.
callCount	ServiceCounterDataType	Counter of the Call Service, identifying the number of received requests of this Service on the session.
createMonitoredItemsCount	ServiceCounterDataType	Counter of the CreateMonitoredItems Service, identifying the number of received requests of this Service on the session.
modifyMonitoredItemsCount	ServiceCounterDataType	Counter of the ModifyMonitoredItems Service, identifying the number of received requests of this Service on the session.
setMonitoringModeCount	ServiceCounterDataType	Counter of the SetMonitoringMode Service, identifying the number of received requests of this Service on the session.
setTriggeringCount	ServiceCounterDataType	Counter of the SetTriggering Service, identifying the number of received requests of this Service on the session.
deleteMonitoredItemsCount	ServiceCounterDataType	Counter of the DeleteMonitoredItems Service, identifying the number of received requests of this Service on the session.
createSubscriptionCount	ServiceCounterDataType	Counter of the CreateSubscription Service, identifying the number of received requests of this Service on the session.
modifySubscriptionCount	ServiceCounterDataType	Counter of the ModifySubscription Service, identifying the number of received requests of this Service on the session.
setPublishingModeCount	ServiceCounterDataType	Counter of the SetPublishingMode Service, identifying the number of received requests of this Service on the session.
publishCount	ServiceCounterDataType	Counter of the Publish Service, identifying the number of received requests of this Service on the session.
republishCount	ServiceCounterDataType	Counter of the Republish Service, identifying the number of received requests of this Service on the session.
transferSubscriptionsCount	ServiceCounterDataType	Counter of the TransferSubscriptions Service, identifying the number of received requests of this Service on the session.
deleteSubscriptionsCount	ServiceCounterDataType	Counter of the DeleteSubscriptions Service, identifying the number of received requests of this Service on the session.
addNodesCount	ServiceCounterDataType	Counter of the AddNodes Service, identifying the number of received requests of this Service on the session.
addReferencesCount	ServiceCounterDataType	Counter of the AddReferences Service, identifying the number of received requests of this Service on the session.
deleteNodesCount	ServiceCounterDataType	Counter of the DeleteNodes Service, identifying the number of received requests of this Service on the session.
deleteReferencesCount	ServiceCounterDataType	Counter of the DeleteReferences Service, identifying the number of received requests of this Service on the session.
browseCount	ServiceCounterDataType	Counter of the Browse Service, identifying the number of received requests of this Service on the session.
browseNextCount	ServiceCounterDataType	Counter of the BrowseNext Service, identifying the number of received requests of this Service on the session.
translateBrowsePathsToNodeIdsCount	ServiceCounterDataType	Counter of the TranslateBrowsePathsToNodeIds Service, identifying the number of received requests of this Service on the session.
queryFirstCount	ServiceCounterDataType	Counter of the QueryFirst Service, identifying the number of received requests of this Service on the session.
queryNextCount	ServiceCounterDataType	Counter of the QueryNext Service, identifying the number of received requests of this Service on the session.
registerNodesCount	ServiceCounterDataType	Counter of the RegisterNodes Service, identifying the number of received requests of this Service on the session.
unregisterNodesCount	ServiceCounterDataType	Counter of the UnregisterNodesService, identifying the number of received requests of this Service on the session.

Its representation in the AddressSpace is defined in Table 147.

Table 147 – SessionDiagnosticsDataType Definition

Attributes	Value
BrowseName	SessionDiagnosticsDataType

12.12 SessionSecurityDiagnosticsDataType

This structure contains security-related diagnostic information about client sessions. Its elements are defined in Table 148. Because this information is security-related, it shall only be accessible by authorised users.

Table 148 – SessionSecurityDiagnosticsDataType Structure

Name	Type	Description
SessionSecurityDiagnosticsDataType	structure
sessionId	NodeId	Server-assigned identifier of the session.
clientUserIdOfSession	String	Name of authenticated user when creating the session.
clientUserIdHistory	String[]	Array containing the name of the authenticated user currently active (either from creating the session or from calling the ActivateSession Service) and the history of those names. Each time the active user changes, an entry shall be made at the end of the array. The active user is always at the end of the array. Servers may restrict the size of this array, but shall support at least a size of 2. How the name of the authenticated user can be obtained from the system via the information received as part of the session establishment is defined in 6.4.3.
authenticationMechanism	String	Type of authentication currently used by the session. The String shall be one of the lexical names of the UserIdentityTokenType Enum.
encoding	String	Which encoding is used on the wire. The String shall be ‘XML’, ‘JSON’ or ‘UA Binary’.
transportProtocol	String	Which transport protocol is used. The String shall be the scheme from the URL used to establish the session. For example, ‘opc.tcp’, ‘opc.wss’ or ‘https’. The formal protocol URL scheme strings are defined in OPC 10000-6.
securityMode	MessageSecurityMode	The message security mode used for the session.
securityPolicyUri	String	The name of the security policy used for the session.
clientCertificate	ByteString	The application instance certificate provided by the client in the CreateSession request.

Its representation in the AddressSpace is defined in Table 149.

Table 149 – SessionSecurityDiagnosticsDataType Definition

Attributes	Value
BrowseName	SessionSecurityDiagnosticsDataType

12.13 ServiceCounterDataType

This structure contains diagnostic information about subscriptions. Its elements are defined in Table 150.

Table 150 – ServiceCounterDataType Structure

Name	Type	Description
ServiceCounterDataType	structure
totalCount	UInt32	The number of Service requests that have been received.
errorCount	UInt32	The total number of Service requests that were rejected.

Its representation in the AddressSpace is defined in Table 151.

Table 151 – ServiceCounterDataType Definition

Attributes	Value
BrowseName	ServiceCounterDataType

12.14 StatusResult

This structure combines a StatusCode and diagnostic information and can, for example, be used by Methods to return several StatusCodes and the corresponding diagnostic information that are not handled in the Call Service parameters. The elements of this DataType are defined in Table 152. Whether the diagnosticInfo is returned depends on the setting of the Service calls.

Table 152 – StatusResult Structure

Name	Type	Description
StatusResult	structure
statusCode	StatusCode	The StatusCode.
diagnosticInfo	DiagnosticInfo	The diagnostic information for the statusCode.

Its representation in the AddressSpace is defined in Table 153.

Table 153 – StatusResult Definition

Attributes	Value
BrowseName	StatusResult

12.15 SubscriptionDiagnosticsDataType

This structure contains diagnostic information about subscriptions. Its elements are defined in Table 154.

Table 154 – SubscriptionDiagnosticsDataType Structure

Name	Type	Description
SubscriptionDiagnosticsDataType	structure
sessionId	NodeId	Server-assigned identifier of the session the subscription belongs to.
subscriptionId	UInt32	Server-assigned identifier of the subscription.
priority	Byte	The priority the client assigned to the subscription.
publishingInterval	Duration	The publishing interval of the subscription in milliseconds
maxKeepAliveCount	UInt32	The maximum keep-alive count of the subscription.
maxLifetimeCount	UInt32	The maximum lifetime count of the subscription.
maxNotificationsPerPublish	UInt32	The maximum number of notifications per publish response.
publishingEnabled	Boolean	Whether publishing is enabled for the subscription.
modifyCount	UInt32	The number of ModifySubscription requests received for the subscription.
enableCount	UInt32	The number of times the subscription has been enabled.
disableCount	UInt32	The number of times the subscription has been disabled.
republishRequestCount	UInt32	The number of Republish Service requests that have been received and processed for the subscription.
republishMessageRequestCount	UInt32	The total number of messages that have been requested to be republished for the subscription. Note that due to the design of the Republish Service this number is always equal to the republishRequestCount.
republishMessageCount	UInt32	The number of messages that have been successfully republished for the subscription.
transferRequestCount	UInt32	The total number of TransferSubscriptions Service requests that have been received for the subscription.
transferredToAltClientCount	UInt32	The number of times the subscription has been transferred to an alternate client.
transferredToSameClientCount	UInt32	The number of times the subscription has been transferred to an alternate session for the same client.
publishRequestCount	UInt32	The number of Publish Service requests that have been received and processed for the subscription.
dataChangeNotificationsCount	UInt32	The number of data change Notifications sent by the subscription.
eventNotificationsCount	UInt32	The number of Event Notifications sent by the subscription.
notificationsCount	UInt32	The total number of Notifications sent by the subscription.
latePublishRequestCount	UInt32	The number of times the subscription has entered the LATE State, i.e. the number of times the publish timer expires and there are unsent notifications.
currentKeepAliveCount	UInt32	The number of times the subscription has entered the KEEPALIVE State.
currentLifetimeCount	UInt32	The current lifetime count of the subscription.
unacknowledgedMessageCount	UInt32	The number of unacknowledged messages saved in the republish queue.
discardedMessageCount	UInt32	The number of messages that were discarded before they were acknowledged.
monitoredItemCount	UInt32	The total number of monitored items of the subscription, including the disabled monitored items.
disabledMonitoredItemCount	UInt32	The number of disabled monitored items of the subscription.
monitoringQueueOverflowCount	UInt32	The number of times a monitored item dropped notifications because of a queue overflow.
nextSequenceNumber	UInt32	Sequence number for the next notification message.
eventQueueOverFlowCount	UInt32	The number of times a monitored item in the subscription has generated an Event of type EventQueueOverflowEventType.

Its representation in the AddressSpace is defined in Table 155.

Table 155 – SubscriptionDiagnosticsDataType Definition

Attributes	Value
BrowseName	SubscriptionDiagnosticsDataType

12.16 ModelChangeStructureDataType

This structure contains elements that describe changes of the model. Its composition is defined in Table 156.

Table 156 – ModelChangeStructureDataType Structure

Name

Type

Description

ModelChangeStructureDataType

structure

affected

NodeId

NodeId of the Node that was changed. The client should assume that the affected Node has been created or deleted, had a Reference added or deleted, or the DataType has changed as described by the verb.

affectedType

NodeId

If the affected Node was an Object or Variable, affectedType contains the NodeId of the TypeDefinitionNode of the affected Node. Otherwise it is set to null.

verb

Byte

Describes the changes happening to the affected Node.

The verb is an 8-bit unsigned integer used as bit mask with the structure defined in the following table:

Field	Bit	Description
NodeAdded	0	Indicates the affected Node has been added.
NodeDeleted	1	Indicates the affected Node has been deleted.
ReferenceAdded	2	Indicates a Reference has been added. The affected Node may be either a SourceNode or TargetNode. Note that an added bidirectional Reference is reflected by two changes.
ReferenceDeleted	3	Indicates a Reference has been deleted. The affected Node may be either a SourceNode or TargetNode. Note that a deleted bidirectional Reference is reflected by two changes.
DataTypeChanged	4	This verb may be used only for affected Nodes that are Variables or VariableTypes. It indicates that the DataType Attribute has changed.
Reserved	5:7	Reserved for future use. Shall always be zero.

A verb may identify several changes on the affected Node at once. This feature should be used if event compression is used (see OPC 10000-3 for details).

Note that all verbs shall always be considered in the context where the ModelChangeStructureDataType is used. A NodeDeleted may indicate that a Node was removed from a view but still exists in other Views.

Its representation in the AddressSpace is defined in Table 157.

Table 157 – ModelChangeStructureDataType Definition

Attributes	Value
BrowseName	ModelChangeStructureDataType

12.17 SemanticChangeStructureDataType

This structure contains elements that describe a change of the model. Its composition is defined in Table 158.

Table 158 – SemanticChangeStructureDataType Structure

Name	Type	Description
SemanticChangeStructureDataType	structure
affected	NodeId	NodeId of the Node that owns the Property that has changed.
affectedType	NodeId	If the affected Node was an Object or Variable, affectedType contains the NodeId of the TypeDefinitionNode of the affected Node. Otherwise it is set to null.

Its representation in the AddressSpace is defined in Table 159.

Table 159 – SemanticChangeStructureDataType Definition

Attributes	Value
BrowseName	SemanticChangeStructureDataType

12.18 BitFieldMaskDataType

This simple DataType is a subtype of UInt64 and represents a bit mask up to 32 bits where individual bits can be written without modifying the other bits.

The first 32 bits (least significant bits) of the BitFieldMaskDataType represent the bit mask and the second 32 bits represent the validity of the bits in the bit mask. When the Server returns the value to the client, the validity provides information of which bits in the bit mask have a meaning. When the client passes the value to the Server, the validity defines which bits should be written. Only those bits defined in validity are changed in the bit mask, all others stay the same. The BitFieldMaskDataType can be used as DataType in the OptionSetType VariableType

Its representation in the AddressSpace is defined in Table 160.

Table 160 – BitFieldMaskDataType Definition

Attributes	Value
BrowseName	BitFieldMaskDataType

12.19 NetworkGroupDataType

This structure contains information on different network paths for one Server. Its composition is defined in Table 161.

Table 161 – NetworkGroupDataType Structure

Name	Type	Description
NetworkGroupDataType	structure
serverUri	String	URI of the Server represented by the network group.
networkPaths	EndpointUrlListDataType[]	Array of different network paths to the server, for example provided by different network cards in a Server node. Each network path can have several Endpoints representing different protocol options for the same path.

Its representation in the AddressSpace is defined in Table 162.

Table 162 – NetworkGroupDataType Definition

Attributes	Value
BrowseName	NetworkGroupDataType

12.20 EndpointUrlListDataType

This structure represents a list of URLs of an Endpoint. Its composition is defined in Table 163.

Table 163 – EndpointUrlListDataType Structure

Name	Type	Description
EndpointUrlListDataType	structure
endpointUrlList	String[]	List of URLs of an Endpoint.

Its representation in the AddressSpace is defined in Table 164.

Table 164 – EndpointUrlListDataType Definition

Attributes	Value
BrowseName	EndpointUrlListDataType

12.21 KeyValuePair

This DataType is used to provide a key value pair. The KeyValuePair is formally defined in Table 165.

Table 165 – KeyValuePair Structure

Name	Type	Description
KeyValuePair	structure
key	QualifiedName	The key of the value.
value	BaseDataType	The value associated with the key.

12.22 EndpointType

This structure describes an Endpoint. The EndpointType is formally defined in Table 166.

Table 166 – EndpointType Structure

Name	Type	Description
EndpointType	structure
endpointUrl	String	The URL for the Endpoint.
securityMode	MessageSecurityMode	The type of message security. The type MessageSecurityMode type is defined in OPC 10000-4.
securityPolicyUri	String	The URI of the SecurityPolicy.
transportProfileUri	String	The URI of the Transport Profile.