This ObjectTypedefines the capabilities supported by the OPC UA Server. It is formally defined in Table 10.

Table 10– ServerCapabilitiesType definition

Attribute

Value

BrowseName

ServerCapabilitiesType

IsAbstract

False

References

NodeClass

BrowseName

DataType / TypeDefinition

ModellingRule

Subtype of the BaseObjectType defined in 6.2

HasProperty

Variable

ServerProfileArray

String[]

PropertyType

Mandatory

HasProperty

Variable

LocaleIdArray

LocaleId[]

PropertyType

Mandatory

HasProperty

Variable

MinSupportedSampleRate

Duration

PropertyType

Mandatory

HasProperty

Variable

MaxBrowseContinuationPoints

UInt16

PropertyType

Mandatory

HasProperty

Variable

MaxQueryContinuationPoints

UInt16

PropertyType

Mandatory

HasProperty

Variable

MaxHistoryContinuationPoints

UInt16

PropertyType

Mandatory

HasProperty

Variable

SoftwareCertificates

SignedSoftwareCertificate[]

PropertyType

Mandatory

HasProperty

Variable

MaxArrayLength

UInt32

PropertyType

Optional

HasProperty

Variable

MaxStringLength

UInt32

PropertyType

Optional

HasProperty

Variable

MaxByteStringLength

UInt32

PropertyType

Optional

HasComponent

Object

OperationLimits

--

OperationLimitsType

Optional

HasComponent

Object

ModellingRules

--

FolderType

Mandatory

HasComponent

Object

AggregateFunctions

--

FolderType

Mandatory

HasComponent

Object

RoleSet

RoleSetType

Optional

HasProperty

Variable

MaxSessions

UInt32

PropertyType

Optional

HasProperty

Variable

MaxSubscriptions

UInt32

PropertyType

Optional

HasProperty

Variable

MaxMonitoredItems

UInt32

PropertyType

Optional

HasProperty

Variable

MaxSubscriptionsPerSession

UInt32

PropertyType

Optional

HasProperty

Variable

MaxMonitoredItemsPerSubscription

UInt32

PropertyType

Optional

HasProperty

Variable

MaxSelectClauseParameters

UInt32

PropertyType

Optional

HasProperty

Variable

MaxWhereClauseParameters

UInt32

PropertyType

Optional

HasProperty

Variable

MaxMonitoredItemsQueueSize

UInt32

PropertyType

Optional

HasComponent

Variable

<VendorCapability>

BaseDataType

ServerVendorCapabilityType

OptionalPlaceholder

HasProperty

Variable

ConformanceUnits

QualifiedName[]

PropertyType

Optional

Conformance Units

Base Info ServerType

ServerProfileArray lists the Profilesthat the Serversupports. The Stringshall be the URI of the Profile. See OPC 10000-7for definitions of OPC UA Server Profiles. This list should be limited to the Profilesthe Serversupports in its current configuration.

LocaleIdArray is an array of LocaleIds that are known to be supported by the Server. The Servermight not be aware of all LocaleIds that it supports because it may provide access to underlying servers, systems or devices that do not report the LocaleIds that they support.

MinSupportedSampleRate defines the minimum supported sample rate, including 0, which is supported by the Server.

MaxBrowseContinuationPointsis an integer specifying the maximum number of parallel continuation points of the Browse Servicethat the Servercan support per session. The value specifies the maximum the Servercan support under normal circumstances, so there is no guarantee the Servercan always support the maximum. The client should not open more Browse calls with open continuation points than exposed in this Variable. The value 0 indicates that the Serverdoes not restrict the number of parallel continuation points the client should use.

MaxQueryContinuationPointsis an integer specifying the maximum number of parallel continuation points of the QueryFirst Servicesthat the Servercan support per session. The value specifies the maximum the Servercan support under normal circumstances, so there is no guarantee the Servercan always support the maximum. The client should not open more QueryFirst calls with open continuation points than exposed in this Variable. The value 0 indicates that the Serverdoes not restrict the number of parallel continuation points the client should use.

MaxHistoryContinuationPoints is an integer specifying the maximum number of parallel continuation points of the HistoryRead Servicesthat the Servercan support per session. The value specifies the maximum the Servercan support under normal circumstances, so there is no guarantee the Servercan always support the maximum. The client should not open more HistoryRead calls with open continuation points than exposed in this Variable. The value 0 indicates that the Serverdoes not restrict the number of parallel continuation points the client should use.

SoftwareCertificatesis an array of SignedSoftwareCertificatescontaining all SoftwareCertificatessupported by the Server. A SoftwareCertificateidentifies capabilities of the Server. It contains the list of Profilessupported by the Server. Profilesare described in OPC 10000-7.

The MaxArrayLength Propertyindicates the maximum length of a one or multidimensional array supported by Variables, Methodarguments and Eventfields of the Server. In a multidimensional array it indicates the overall length. For example, a three-dimensional array of 2x3x10 has the array length of 60. The Servermight further restrict the length for individual Variables, Methodarguments or Eventfields without notice to the client. Serversmay use the Property MaxArrayLengthdefined in OPC 10000-3on individual DataVariablesto specify the size on individual values. The individual Propertymay have a larger or smaller value than MaxArrayLength.

The MaxStringLength Propertyindicates the maximum number of bytes in Strings andLocalizedTextsupported by Variables, Method arguments andEvent fields of the Server. Serversmay override this setting by adding the MaxStringLength Propertydefined in OPC 10000-3to an individual DataVariable. If a Serverdoes not impose a maximum number of bytes or is not able to determine the maximum number of bytes this Propertyshall not be provided.

The MaxByteStringLength Propertyindicates the maximum number of bytes in a ByteStringsupported by Variables, Method argumentsandEvent fields of the Server. Servers may override this setting by adding the MaxByteStringLength Propertydefined in OPC 10000-3to an individual DataVariable. If a Serverdoes not impose a maximum number of bytes or is not able to determine the maximum number of bytes this Propertyshall not be provided.

OperationLimitsis an entry point to access information on operation limits of the Server, for example the maximum length of an array in a read Servicecall.

ModellingRulesis an entry point to browse to all ModellingRulessupported by the Server. All ModellingRulessupported by the Servershould be able to be browsed starting from this Object.

AggregateFunctionsis an entry point to browse to all AggregateFunctionssupported by the Server. All AggregateFunctionssupported by the Servershould be able to be browsed starting from this Object. AggregateFunctions are Objects of AggregateFunctionType.

The RoleSet Objectis used to publish all Rolessupported by the Server. The RoleSetTypeis specified in OPC 10000-18.

MaxSessionsis an integer specifying the maximum number of concurrent Sessionsthe Servercan support. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxSubscriptionsis an integer specifying the maximum number of Subscriptionsthe Servercan support. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxMonitoredItemsis an integer specifying the maximum number of MonitoredItemsthe Servercan support. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxSubscriptionsPerSession is an integer specifying the maximum number of Subscriptionsper Sessionthe Servercan support. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxMonitoredItemsPerSubscription is an integer specifying the maximum number of MonitoredItemsper Subscriptionthe Servercan support. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxSelectClauseParameters is an integer specifying the maximum number of EventField SelectClause Parameters the Servercan support for an EventFilter. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxWhereClauseParameters is an integer specifying the maximum number of EventField WhereClause Parameters the Servercan support for an EventFilter. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

MaxMonitoredItemsQueueSize is an integer specifying the maximum size of data MonitoredItemqueues. The value specifies the maximum the Servercan support under normal circumstances, therefore there is no guarantee the Servercan always support the maximum.

When a vendor can not determine a limit of an optional component then the component shall not be included.

When vendors expose their own capabilities, they should add additional Nodesto the standard ServerCapabilities Objectinstance.

The <VendorCapability> Variableis used to provide information about the server-specific capabilities.

ConformanceUnitsis a QualifiedNamearray specifying the set of conformance units the Serversupports. This list should be limited to the ConformanceUnitsthe Serversupports in its current configuration.