Field

Bit Range

Description

Severity

30:31

Indicates whether the StatusCode represents a good, bad or uncertain condition. These bits have the following meanings:

Reserved

29:29

Reserved for use in OPC UA application specific APIs. This bit shall always be zero on the wire but may be used by OPC UA application specific APIs for API specific status codes.

Reserved

28:28

Reserved for future use. Shall always be zero.

SubCode

16:27

The code is a numeric value assigned to represent different conditions. Each code has a symbolic name and a numeric value. All descriptions in the OPC UA specification refer to the symbolic name. OPC 10000-6 maps the symbolic names onto a numeric value.

StructureChanged

15:15

Indicates that the structure of the associated data value has changed since the last Notification. Clients should not process the data value unless they re-read the metadata.

Servers shall set this bit if the DataTypeDefinition of the DataType used for a Variable changes.

This bit is provided to warn Clients that parse complex data values that their parsing routines could fail because the serialized form of the data value has changed.

This bit has meaning only for StatusCodes returned as part of a data change Notification or the HistoryRead. StatusCodes used in other contexts shall always set this bit to zero.

The bit is set on one data change Notification per MonitoredItem that samples values at the time the structure change happened. If the data change notification with the bit set is deleted because of a queue overflow, the bit must be set on the next data change notification in the queue.

SemanticsChanged

14:14

Indicates that the semantics of the associated data value have changed. Clients should not process the data value until they re-read the metadata associated with the Variable.

Servers should set this bit if the metadata has changed in way that could cause application errors if the Client does not re-read the metadata. For example, a change to the engineering units could create problems if the Client uses the value to perform calculations.

OPC 10000-8 defines the conditions where a Server shall set this bit for a DA Variable. Other specifications may define additional conditions. A Server may define other conditions that cause this bit to be set.

This bit has meaning only for StatusCodes returned as part of a data change Notification or the HistoryRead. StatusCodes used in other contexts shall always set this bit to zero.

The bit is set on one data change Notification per MonitoredItem that samples values at the time the semantic change happened. If the data change notification with the bit set is deleted because of a queue overflow, the bit must be set on the next data change notification in the queue.

Reserved

12:13

Reserved for future use. Shall always be zero.

InfoType

10:11

The type of information contained in the info bits. These bits have the following meanings:

InfoBits

0:9

Additional information bits that qualify the StatusCode.

The structure of these bits depends on the Info Type field.

Info Type

Bit Range

Description

LimitBits

8:9

The limit bits associated with the data value. The limits bits have the following meanings:

Overflow

7

This bit shall only be set if the MonitoredItem queue size is greater than 1.

If this bit is set, not every detected change has been returned since the Server’s queue buffer for the MonitoredItem reached its limit and had to purge out data.

Reserved

5:6

Reserved for future use. Shall always be zero.

HistorianBits

0:4

These bits are set only when reading historical data. They indicate where the data value came from and provide information that affects how the Client uses the data value. The historian bits have the following meaning:

OPC 10000-11 describes how these bits are used in more detail.

Symbolic Id

Description

Good

The operation was successful.

Good_CompletesAsynchronously

The processing will complete asynchronously.

Good_SubscriptionTransferred

The Subscription was transferred to another session.

Bad_CertificateHostNameInvalid

The HostName used to connect to a Server does not match a HostName in the Certificate.

Bad_CertificateChainIncomplete

The Certificate chain is incomplete.

Bad_CertificateIssuerRevocationUnknown

It was not possible to determine if the Issuer Certificate has been revoked.

Bad_CertificateIssuerUseNotAllowed

The Issuer Certificate may not be used for the requested operation.

Bad_CertificateIssuerTimeInvalid

An Issuer Certificate has expired or is not yet valid.

Bad_CertificateIssuerRevoked

The Issuer Certificate has been revoked.

Bad_CertificateInvalid

The Certificate provided as a parameter is not valid.

Bad_CertificateRevocationUnknown

It was not possible to determine if the Certificate has been revoked.

Bad_CertificateRevoked

The Certificate has been revoked.

Bad_CertificateTimeInvalid

The Certificate has expired or is not yet valid.

Bad_CertificateUriInvalid

The URI specified in the ApplicationDescription does not match the URI in the Certificate.

Bad_CertificateUntrusted

The Certificate is not trusted.

Bad_CertificateUseNotAllowed

The Certificate may not be used for the requested operation.

Bad_CommunicationError

A low level communication error occurred.

Bad_DataTypeIdUnknown

The ExtensionObject cannot be (de)serialized because the data type id is not recognized.

Bad_DecodingError

Decoding halted because of invalid data in the stream.

Bad_EncodingError

Encoding halted because of invalid data in the objects being serialized.

Bad_EncodingLimitsExceeded

The message encoding/decoding limits imposed by the Communication Stack have been exceeded.

Bad_IdentityTokenInvalid

The user identity token is not valid.

Bad_IdentityTokenRejected

The user identity token is valid but the Server has rejected it.

Bad_InternalError

An internal error occurred as a result of a programming or configuration error.

Bad_InvalidArgument

One or more arguments are invalid.

Each service defines parameter-specific StatusCodes and these StatusCodes shall be used instead of this general error code. This error code shall be used only by the Communication Stack and in services where it is defined in the list of valid StatusCodes for the service.

Bad_InvalidState

The operation cannot be completed because the object is closed, uninitialized or in some other invalid state.

Bad_InvalidTimestamp

The timestamp is outside the range allowed by the Server.

Bad_LicenseExpired

The UA Server requires a license to operate in general or to perform a service or operation, but existing license is expired

Bad_LicenseLimitsExceeded

The UA Server has limits on number of allowed operations / objects, based on installed licenses, and these limits where exceeded.

Bad_LicenseNotAvailable

The UA Server does not have a license which is required to operate in general or to perform a service or operation.

Bad_NonceInvalid

The nonce does appear to be not a random value or it is not the correct length.

Bad_NothingToDo

No processing could be done because there was nothing to do.

For Service level results the code is used if the Client passed a list of operations with no elements.

Bad_OutOfMemory

Not enough memory to complete the operation.

Bad_RequestCancelledByClient

The request was cancelled by the Client.

Bad_RequestTooLarge

The request message size exceeds limits set by the Server.

Bad_ResponseTooLarge

The response message size exceeds limits set by the Client.

Bad_RequestHeaderInvalid

The header for the request is missing or invalid.

Bad_ResourceUnavailable

An operating system resource is not available.

Bad_SecureChannelIdInvalid

The specified secure channel is no longer valid.

Bad_SecurityChecksFailed

An error occurred while verifying security.

Bad_SecurityPolicyRejected

The security policy does not meet the requirements set by the Server.

Bad_ServerHalted

The Server has stopped and cannot process any requests.

Bad_ServerNotConnected

The operation could not complete because the Client is not connected to the Server.

Bad_ServerTooBusy

The Server does not have the resources to process the request at this time.

This can be caused by a general overload of the Server or an overload by the Client that receives the result code.

Bad_ServerUriInvalid

The Server URI is not valid.

Bad_ServiceUnsupported

The Server does not support the requested service.

Bad_SessionIdInvalid

The Session id is not valid.

Bad_SessionClosed

The Session was closed by the Client.

Bad_SessionNotActivated

The Session cannot be used because ActivateSession has not been called.

Bad_Shutdown

The operation was cancelled because the application is shutting down.

Bad_SubscriptionIdInvalid

The Subscription id is not valid.

Bad_Timeout

The operation timed out.

Bad_TimestampsToReturnInvalid

The timestamps to return parameter is invalid.

Bad_TooManyOperations

The request could not be processed because it specified too many operations.

Bad_UnexpectedError

An unexpected error occurred.

Bad_UnknownResponse

An unrecognized response was received from the Server.

Bad_UserAccessDenied

User does not have permission to perform the requested operation.

Bad_ViewIdUnknown

The view id does not refer to a valid view Node.

Bad_ViewTimestampInvalid

The view timestamp is not available or not supported.

Bad_ViewParameterMismatchInvalid

The view parameters are not consistent with each other.

Bad_ViewVersionInvalid

The view version is not available or not supported.

Symbolic Id

Description

Good_Clamped

The value written was accepted but was clamped.

Good_Overload

Sampling has slowed down due to resource limitations.

Uncertain

The value is uncertain but no specific reason is known.

Bad

The value is bad but no specific reason is known.

Bad_AttributeIdInvalid

The attribute is not supported for the specified node.

Bad_BrowseDirectionInvalid

The browse direction is not valid.

Bad_BrowseNameInvalid

The browse name is invalid.

Bad_ContentFilterInvalid

The content filter is not valid.

Bad_ContinuationPointInvalid

The continuation point provided is no longer valid.

This status is returned if the continuation point was deleted or the address space was changed between the browse calls.

Bad_DataEncodingInvalid

The data encoding is invalid.

This result is used if no dataEncoding can be applied because an Attribute other than Value was requested or the DataType of the Value Attribute is not a subtype of the Structure DataType.

Bad_DataEncodingUnsupported

The Server does not support the requested data encoding for the node.

This result is used if a dataEncoding can be applied but the passed data encoding is not known to the Server.

Bad_EventFilterInvalid

The event filter is not valid.

Bad_FilterNotAllowed

A monitoring filter cannot be used in combination with the attribute specified.

Bad_FilterOperandInvalid

The operand used in a content filter is not valid.

Bad_HistoryOperationInvalid

The history details parameter is not valid.

Bad_HistoryOperationUnsupported

The Server does not support the requested operation.

Bad_IndexRangeInvalid

The syntax of the index range parameter is invalid.

Bad_IndexRangeNoData

No data exists within the range of indexes specified.

Bad_MonitoredItemFilterInvalid

The monitored item filter parameter is not valid.

Bad_MonitoredItemFilterUnsupported

The Server does not support the requested monitored item filter.

Bad_MonitoredItemIdInvalid

The monitoring item id does not refer to a valid monitored item.

Bad_MonitoringModeInvalid

The monitoring mode is invalid.

Bad_NoCommunication

Communication with the data source is defined, but not established, and there is no last known value available.

This status/sub-status is used for cached values before the first value is received or for Write and Call if the communication is not established.

Bad_NoContinuationPoints

The operation could not be processed because all continuation points have been allocated.

Bad_NodeClassInvalid

The node class is not valid.

Bad_NodeIdInvalid

The syntax of the node id is not valid or refers to a node that is not valid for the operation.

Bad_NodeIdUnknown

The node id refers to a node that does not exist in the Server address space.

Bad_NoDeleteRights

The Server will not allow the node to be deleted.

Bad_NodeNotInView

The nodesToBrowse is not part of the view.

Bad_NotFound

A requested item was not found or a search operation ended without success.

Bad_NotImplemented

Requested operation is not implemented.

Bad_NoValue

There is no value available.

The status is used if a Variable is created and no default value or no initial value is available.

Bad_NotReadable

The access level does not allow reading or subscribing to the Node.

Bad_NotSupported

The requested operation is not supported.

Bad_NotWritable

The access level does not allow writing to the Node.

Bad_ObjectDeleted

The Object cannot be used because it has been deleted.

Bad_OutOfRange

The value was out of range.

Bad_ReferenceTypeIdInvalid

The reference type id does not refer to a valid reference type node.

Bad_SecurityModeInsufficient

The SecurityPolicy and/or MessageSecurityMode do not match the Server requirements to complete the operation.

For example, a user may have the right to receive the data but the data can only be transferred through an encrypted channel with an appropriate SecurityPolicy.

Bad_SourceNodeIdInvalid

The source node id does not refer to a valid node.

Bad_StructureMissing

A mandatory structured parameter was missing or null.

Bad_TargetNodeIdInvalid

The target node id does not refer to a valid node.

Bad_TypeDefinitionInvalid

The type definition node id does not reference an appropriate type node.

Bad_TypeMismatch

The value supplied for the attribute is not of the same type as the attribute's value.

Bad_WaitingForInitialData

Waiting for the Server to obtain values from the underlying data source.

After creating a MonitoredItem or after setting the MonitoringMode from DISABLED to REPORTING or SAMPLING, it may take some time for the Server to actually obtain values for these items. In such cases the Server can send a Notification with this status prior to the Notification with the first value or status from the data source.