Internal datapoints of the OPC UA client

_OPCUA

A datapoint _OPCUA<num> of this type is used for several configuration settings for each OPC UA client. <num> stands for the manager number of the started client. By default, 3 datapoints of this type already exist: _OPCUA1, _OPCUA2 and _OPCUA3.

Datapoint element Type Description
Config.AlarmPrioMapping dyn_string Defines the mapping of OPC UA severities to WinCC OA alert classes.

A mapping has the following format:

<OPC UA startSeverity1> <WinCC OA alertClass1>
<OPC UA startSeverity2> <WinCC OA alertClass2>
                                ...

An example of such a mapping is:

0 OPCUA_info
250 OPCUA_warning
500 OPCUA_alarm
1000 OPCUA_danger

I.e.:

  • If an alarm with a severity of 150 is received, this belongs to the WinCC OA alert class "OPCUA_info".
  • If an alarm with a severity of 499 is received, this belongs to the WinCC OA alert class "OPCUA_warning".
  • If an alarm with a severity of 500 is received, this belongs to the WinCC OA alert class "OPCUA_alarm".
  • If an alarm with a severity of 1000 (highest OPC UA severity) is received, this belongs to the WinCC OA alert class "OPCUA_danger".
Tip:
For further information see Mapping of alarm data.
Config.Servers dyn_string Defines which servers are assigned to a client with the corresponding manager number. The appropriate OPC UA server data point must be inserted without the leading "_" character. If there is a periphery address for the server, the server datapoint is inserted automatically.
Config.HistoryReadResponseDps dyn_string The response datapoints must be registered on this datapoint element in order to write historical data to them. See also _OPCUAHistoryReadResponse.
Config.LocalDiscoveryServers dyn_string List of local discovery servers that the driver uses to resolve URIs when the connection endpoint is specified as a URI rather than a URL.
Command.AddServer string Can be used for assigning an OPC UA server to a client dynamically (without using the server config entry and a resulting restart). Therefore, the OPC UA server datapoint must be inserted. The server can thus be added dynamically without creating a peripheral address.
Discovery.Discover dyn_string Use this DPE to start discovery. The dyn_string contains two elements. The first is an arbitrary request ID, which is echoed in the result so you can match the response to the request. The second is the discovery URL.
Discovery.RequestId string Returns the request ID to assign the response to the discovery request. The driver sets the resulting DPEs in a single dpSet.
Discovery.ApplicationNames dyn_string Discovered application names
Discovery.ApplicationUris dyn_string Discovered application URIs
Discovery.DiscoveryUrls dyn_string Discovered discovery URLs
Discovery.EndpointUrls dyn_string Discovered endpoint URLs
Discovery.ProductUris dyn_string Discovered product URIs
Gds.Config.Address string The address of the GDS server, e.g. opc.tcp://gdshost:48060
Gds.Config.UpdateTrustListInterval uint The interval in seconds for GDS interaction
Gds.State.RegistrationStatus uint The registration status enum of the driver, used for diagnostics
Gds.State.AvailableCertificateGroups dyn_string The available certificate groups in the GDS
Gds.State.ApplicationId string The application ID received from the GDS, used for interaction also after driver restart
Gds.State.LastTrustListUpdate time Timestamp of the last trust list update
Gds.State.LastCertificateUpdate time Timestamp of the last certificate update

_OPCUAHistoryReadResponse

If a datapoint of this type is created and entered at _OPCUA.Config.HistoryReadResponseDps, data of historical requests can be mapped onto it. The elements of this type are described in the following table.

Datapoint element Type Description
RequestId string Shows the ReguestId used for triggering the history read request. This element can be used to associate the result of a request with the specific request.
ReturnCode int The return code for the triggered history read request. The following values are possible:
  • -0 - The specified parameters for the history read request were valid and the service request was sent to the server.
  • -1 - No RequestID or no connection to the server, no history read request was sent to the server
  • -2 - Unknown Function, no history read request was sent to the server
  • -3 - Unknown Method, no history read request was sent to the server
  • -4 - No matching peripheral addresses found, no history read request was sent to the server
DpList dyn_string In case that a peripheral address wildcard was defined in the parameters, this DPE contains a list of the appropriate datapoint elements where the corresponding peripheral addresses are configured (only when using method 3).
ResultCodes dyn_int The result codes for the history read request. If a peripheral address wildcard was defined in the parameters then this DPE contains a list of result codes for the appropriate datapoint elements.

The following values are possible:

  • -0 - The OPC UA server returned the status code “Good” for the history read request
  • -1 - The OPC UA server returned the status code “Bad” or “Uncertain” for the history read request
  • -2 - The parameters for the history read request are invalid and no request was sent to the OPC UA server
NodeStatusCodes dyn_bit32 The OPC UA node status code from the history read request. If a peripheral address wildcard was defined in the parameters then this DPE will contain a list of OPC UA node status codes for the appropriate server nodes.
DataType string The data type of the variable for which a history read request was triggered.

This DPE is only set if either method NodeId or BrowsePath was defined in the parameters.
DataValues dyn_string The historical values returned for the read request.

This DPE is only set if either method NodeId or BrowsePath was defined in the parameters.
SourceTimestamps dyn_time The source timestamps in local time returned for the history read request.

This DPE is only set if either method NodeId or BrowsePath was defined in the parameters.
ServerTimestamps dyn_time The server timestamps in local time returned for the history read request.

This DPE is only set if either method NodeId or BrowsePath was defined in the parameters.
ValueStatusCodes dyn_bit32 The OPC UA value status codes returned for the history read request.

This DPE is only set if either method NodeId or BrowsePath was defined in the parameters.

_OPCUAServer

A datapoint of this type contains the configuration and status information of an OPC UA server to which the client connects to.

The connection and security settings will not be applied until the server has been restarted. This means that the connection is not automatically terminated and established with the new parameters.

The elements of this type are described in the following table.

Datapoint element Type Description
Config.ConnInfo string Specifies the server URL. This defines how the server can be reached. An example for the format is:

opc.tcp://localhost:4841
Config.AccessInfo string Contains the user name for the access to the server. If the data point element is empty, the client logs in anonymously.
Config.Flags bit32 Each bit (0-based counting) allows additional settings for the OPC UA Client.
bit 0
Registration of Node IDs for faster access. Set this bit (=1) only if Node IDs are supported and if mainly polling is used instead of subscriptions.
bit 1
Setting this bit (=1) disables Monitored Items on passive WinCC OA.
bit 2
Setting this bit (=1) disables Monitored Items on passive OPC UA server.
bit 3
Setting the bit (=1) will delay the creation of subscriptions within the client until the server returns the state "Running".
Warning:
Please make sure, that the server supports the state "Running", otherwise no subscriptions will be created.
bit 4
Setting the bit (=1) defines that only the active driver connects to the PLC.
bit 8
Setting the bit (=1) allows the client to communicate with OPC UA server that do not support secure communication.
CAUTION:
The setting must only be used if your plant provides a secure environment as it will lead to unencrypted transmissions of passwords between client and server.
bit 9
Setting the bit (=1) allows the client to communicate with an OPC UA server that does not provide a valid certificate.
Note:
This setting must only be used if the server cannot be updated with a valid certificate!
bit 10
Setting this bit (=1) allows the client to communicate with an OPC UA server for which valid certificates have been revoked.
bit 11
Setting this bit (=1) allows the client to ignore the errors produced by the certificate issuer revocation list check.
bit 12
Setting this bit (=1) allows the client to communicate with an OPC UA server when valid certificates have expired.
bit 13
Setting this bit (=1) allows the client to communicate with an OPC UA server for which no valid hostname has been provided.
Config.NamespaceTable dyn_string The DPE defines custom numeric IDs for a Node’s namespace. These IDs replace the namespace index in the Node ID configuration. The OPC UA client transfers these IDs to the index by reading the NamespaceArray of the OPC UA server.

Follow these rules when converting namespace indices (for the syntax, see at the end of this chapter):

  1. If the DPE _OPCUAServer.Config.NamespaceTable is empty, no conversion takes place and the WinCC OA configuration uses the regular namespace index.
  2. Namespaces with indices 0 and 1 are predefined by the OPC UA specification and cannot be mapped. Therefore, do not use 0 or 1 as an ID.
  3. If the NamespaceTable contains entries, it must include all namespaces used by the WinCC OA client, each mapped to an ID (excluding the predefined namespaces with indices 0 and 1).
  4. Browse-path addressing in WinCC OA still requires fixed namespace indices because the mapping is not applied to browse paths.
  5. Since debug messages may include the namespace IDs or indices, it is recommended to define IDs that do not coincide with the actual namespace indices, although this is not mandatory.
Config.Password blob Contains the password for the access to the server. The password is displayed encoded.
Remember:
If the password on the server was changed, the changes also have to be updated on the client in order to decode the password correctly.
Config.Security.Policy uint The following security policies are possible:
  • None (0)
  • Basic128Rsa15 (2)
  • Basic256 (3)
  • Basic256Sha256 (4)
  • Aes128Sha256RsaOaep (5)
  • Aes256Sha256RsaPss (6)
Config.Security.MessageMode uint The following message concepts are possible:
  • None (0)
  • Sign (1)
  • Sign&Encrypt (2)
Config.Security.Certificate string Certificate which should be used by the client for connection establishment (example: myCertificate.der).

If this field is empty, the client uses "WinCC_OA_UA_Client.der".
Config.Active bool With this datapoint element the communication to the corresponding server can be deactivated (FALSE) and activated (TRUE).
Config.ReconnectTimer uint Time interval in seconds the driver tries to establish a connection to the server, if no connection is available.
Config.StatusMapping dyn_string Specifies the mapping of the OPC UA status codes to WinCC OA user bits.

The mapping is specified in a dyn_string. The dyn_string contains entries in the following form:

<UA status code><space><user bit number>

Whereas one user bit on the right side can be used multiple times:

For example:

0x00000000 1
0x80280000 2
0x80300000 2
2150891520 32
Config.StatusFilter dyn_uint Allows defining OPC UA status filters for incoming data values. This means that values from the OPC UA server are filtered and discarded based on the UPC UA status.

It is possible to specify several status filters.
Config.Separator string Separator for the view of the display names.
Config.Subscriptions dyn_dpid A subscription is always uniquely assigned to a server. A server can have multiple subscriptions. In this internal datapoint element the corresponding subscriptions are stored in the format: 
<systemName>:_<subscriptionName>
Config.HistoryReadTimestamps uint Defines which timestamp is applied when using method 3 (writing historical data to _archive config of the appropriate datapoint element). The following values can be set:
  • 0 (default) - Timestamp of the subscription of the appropriate datapoint element. If no subscription is defined the source timestamp is used.
  • 1 - Timestamp of the subscription of the appropriate data point element. If no subscription is defined the server timestamp is used.
State.ConnState uint Indicates the connection status to the server:
  • Not connected (0)
  • Connected (1)
  • Failure (5)
State.ServerState string Displays the server status. The usual state is "Running" which means that everything is OK. Otherwise an error status is indicated.
State.StartTime time Displays the startup time of the server.

Format:

JJJJ.MM.TT HH:MM:SS:MMM
State.TimeoutError int Contains information of timeout errors. Possible values:
  • 0 - no error
  • 1 - error during read (actually not used)
  • 2 - error during write
State.TimeoutItems string Lists all items for which the operation fails and a timeout error occurs.
State.VendorInfo string Displays the vendor information of the server.
Command.GQ uint Triggers a general query on the server. The specified value indicates whether values, alarms or both are queried:
  • values and alarms (0)
  • values only (1)
  • alarms only (2)
Command.HistoryRead dyn_string Historical read requests are triggered via this element. The following parameters must be specified.
Index Range Description
1 - RequestID

Allows you to define a unique ID in order to match the result of a request to a specific request.
2 - Function

Currently only the function ReadRaw is supported.
3 1|2|3 Method

Defines the method of the request / processing of the received data. The following methods are possible:

  • 1: NodeId
  • 2: BrowsePath
  • 3: Peripheral adress (wildcards are supported)
4 - Variable

Depending on the used method, either the node ID, browse path or peripheral address must be specified here.

Note:
History read requests are not possible for all nodes (see also notes and restrictions).
5 - startTime

Defines the start time for the read request. The following format must be used:

YYYY-MM-DD HH:MM:SS

The given time is the local time. The OPC UA client converts this time to UTC internally and transmits the historical request with this UTC time.

In case that no start time shall be used, an empty string must be specified.
6 - endTime

Defines the end time for the read request. The following format must be used:

YYYY-MM-DD HH:MM:SS

The given time is the local time. The OPC UA client converts this time to UTC internally and transmits the historical request with this UTC time.

If an end time is not used, an empty string must be specified.
7 >=0 maxNumValuesPerNode

Defines the maximum number of values returned for the defined time range.
8 0|1 returnBounds

Defines whether limit values ​​should be returned.
9 - DP name

The name of the datapoint onto which the result of the read request shall be mapped. The specified datapoint must be of type _OPCUAHistoryReadResponse and entered at _OPCUA.Config.HistoryReadResponseDps
Important:
At least two of the parameters startTime, endTime und maxNumValuesPerNode must be set!
Note:
There are the following special use cases:
  • startTime and maxNumValuesPerNode are set: The defined number of values is returned starting from the given start time.
  • endTime and maxNumValuesPerNode are set: The defined number of values is returned backwards starting from the given end time.

    Example: 

    endTime = 2015-03-03 09:20:00
maxNumValuesPerNode = 3

    Result: 

    2015.03.03 09:19:50.000
2015.03.03 09:18:50.000
2015.03.03 09:17:50.000
  • endTime < startTime: In this case the values are also returned in reverse order.
Redu.Config.ConnInfo string Specifies the server URL of the redundant server. This defines how to connect the OPC UA server. An example of the format is:

opc.tcp://localhost:4841
Redu.Config.Active bool With this datapoint element the communication to the redundant server can be switched off (FALSE) and switched on (TRUE).
Redu.Config.HistoryReadMode uint Defines the behavior for historical requests in case of redundant OPC UA servers. The following values are possible:
  • 0 - The HistoryRead request is sent to the first accessible server. This is the default behavior if a connection to an OPC UA server is configured.
  • 1 - The HistoryRead request is sent to both redundant servers. The result of these two service requests is merged. For merging the historical data values the source timestamps are used. If the server does not provide source timestamps, the server timestamps of the history read results will be used.
Redu.Config.InputMode uint Defines the input data source within a redundant server pair.

The allowed values are:

  • 0 - take input data from both server (as it is up to now)
  • 1 - take input data only form server 1
  • 2 - take input data only from server 2
  • 3 - take the input data from the server with higher service level

If a server is explicitly selected than the client does not use values of the other server, even if the connection to the selected server fails. In that case the application has to switch manually to the other server.

The option only affects input data. In any case, output values ​​are written to both servers.
Redu.State.ConnState uint Indicates the connection status to the redundant server.
  • not connected (0)
  • connected (1)
Redu.State.ServerState string Indicates the server status of the redundant server (Good or Bad).
Redu.State.StartTime time Indicates the start time of the redundant server. Format:

JJJJ.MM.TT HH:MM:SS:MMM
Redu.State.TimeoutError int Contains information of timeout errors. Possible values:
  • 0 ... no error
  • 1 ... error during read (actually not used)
  • 2 ... error during write
Redu.State.TimeoutItems string Lists all items for which the operation fails and a timeout error occurs.
Redu.State.VendorInfo string Indicates the vendor name of the redundant server.
Browse.GetBranch dyn_string With the aid of this datapoint element browsing is triggered. The following is saved:
  • Id - Id of the requests (assigned by the UI, used to match a reply with the request.)
  • ServerName | S1
  • StartNode | ns=1;s=SYSTEM
  • Level | 0 (recursive), >0 (number of levels downwards)
Browse.GetAlarmTypes dyn_string Alarm type browsing is triggered via this datapoint element. The dyn_string contains only the ID from the UI (see Browse.GetBranch).

The function corresponds to Browse.GetBranchbut . ConditionType is always used as the start node, any number of levels down are used, and only nodes representing alarm types are returned.
Browse.RequestId string The client writes to this datapoint element the ID from . Browse.GetBranch or Browse.GetAlarmTypes, to be able to tell the user which request is being answered if there are multiple concurrent users.
Browse.DisplayNames dyn_string View of the names up from the start node. The levels are separated with a separator that was defined in the server data point.

For example:

Folder?stringArray
Browse.BrowsePaths dyn_string View of the whole browsing path in the defined notation beginning at the node /0:Objects: 
/1:AGENT/1:Objects/1:pUInt32
Note:
Special characters as / . < > : # ! & are disguised by &.
Browse.NodeIds dyn_string View of each NodeId per browsed node in the defined notation:

ns=1;s=AGENT.Objects.pUInt32
Browse.NodeClasses dyn_string View of each NodeClass per browsed node:
  • OpcUa_NodeClass_Unspecified
  • OpcUa_NodeClass_Object
  • OpcUa_NodeClass_Variable
  • OpcUa_NodeClass_Method
  • OpcUa_NodeClass_ObjectType
  • OpcUa_NodeClass_VariableType
  • OpcUa_NodeClass_ReferenceType
  • OpcUa_NodeClass_DataType
  • OpcUa_NodeClass_View
Browse.DataTypes dyn_string View of the data type.
Browse.ValueRanks dyn_string View of the value rank.
Browse.AccessLevel dyn_bit32 A bit mask indicating whether the current value of the Value Attribute is readable and writeable as well as whether the history of the value is readable and writeable.
Field Bit Description
CurrentRead 0 Indicates if the current value is readable
CurrentWrite 1 Indicates if the current value is writable.
HistoryRead 2 Indicates if the history of the value is readable.
HistoryWrite 3 Indicates if the history of the value is writable.
SemanticChange 4 Indicates if the Variable used as property generates SemanticChangeEvents.
Reserved 5-7 Reserved for future use. Shall always be zero.

_OPCUASubscription

This datapoint type provides the configuration of subscriptions and the indication of their status. There are some subscription parameters, which can be configured but might be overwritten by the server. For these parameters there is a datapoint element for configuration (Requested) and one which displays the actual value (Revised*).

Datapoint element Type Default-Werte Description
Config.RequestedLifetimeCount uint 100 Number of publishing intervals until the subscription is deleted by the server, if no publish request has been received.
Config.RequestedMaxKeepAliveCount uint 10 When the publishing timer in the server has expired this number of times without data to be sent, the subscription sends a keep-alive Message to the Client.
Config.RequestedPublishingInterval uint 500 In these intervals in seconds the values are read from the server's queues by the client. The intervals are set in milliseconds.
Config.MaxNotificationsPerPublish uint 0 This DPE can be used to specify a limit for notifications the server shall send as response to a Publish request. It can be used to reduce peaks of communication load, when buffered data are transmitted.

The value 0 means that the client does not specify a limit and the server will use the maximum number of notifications per publish.

The maximum values are server dependent, e.g. the WinCC OA OPC UA server has a maximum value of 65535
Config.PublishingEnabled bool FALSE Activates (TRUE) and deactivates (FALSE) a subscription ((no) reaction on value changes).
Config.Priority uint 0 This value indicates with which priority the notifications of this subscription are sent by the server.

Value range: 0 - 255;

whereby 0 means no special priority and 255 the highest priority.
Config.SubscriptionType uint 1 Defines whether this is a subscription on :
  • Data (1)
  • Events (2)
  • Alarms & Conditions (3)
  • undefined (0) - not selectable in the panel
Config.MonitoredItems.TimestampsToReturn uint 3 Indicates which timestamp of the node should be used.

In WinCC OA the corresponding availability is defined by:

  • Source (0)
  • Server (1)
  • Reserved (2)
  • None (3) - OPC UA client passes timestamp.
Config.MonitoredItems.QueueSize uint 1 Number of value changes of the items, which will be stored until the next publish.
Config.MonitoredItems.DiscardOldest bool TRUE Defines whether the oldest elements (TRUE - default) or the youngest elements (FALSE) are discarded from the queue, if the queue overflows.
Config.MonitoredItems.SamplingInterval uint 0 Interval the server uses for querying the monitored items from the underlaying system in milliseconds.
Config.MonitoredItems.DataChangeFilter.Trigger uint 1 Defines the trigger to which the filter applies:
  • Status (0)
  • Status, Value (1)
  • Status, Value, Timestamp (2)
Config.MonitoredItems.DataChangeFilter.DeadbandType uint 0 Defines the deadband type for value calculation:
  • none (0)
  • absolute (1)
  • percent (2)
Config.MonitoredItems.DataChangeFilter.DeadbandValue uint 0 Value in whose range from the original value up the deadband is valid.
Config.Alarm.Acknowledgment dyn_string - Not used.
Config.Alarm.AlarmType string - OPC UA alarm type node ID.
State.AssignedOPCUAServer string - Name of the OPC UA server to which the subscription is assigned.
State.MonitoredItems.FailedReg uint - The DPE counts the number of items where the registration to the subscription failed, so if no error occurred the DPE remains with the value 0.

The DPE can be used by the application to verify if all addresses were correctly subscribed.
State.MonitoredItems.RevisedQueueSize uint - Minimum returned queue size for the monitored items in this subscription
State.MonitoredItems.RevisedSamplingInterval uint - Maximum returned sampling interval for the monitored items in this subscription
State.SubscriptionId uint - Internal identification number for every subscription. This is unique for each server.
  • 0 = invalid
State.RevisedLifetimeCount uint - Returned LifeTimeCount.
State.RevisedMaxKeepAliveCount uint - Returned MaxKeepAliveCount.
  • 0 = invalid
State.RevisedPublishingInterval uint - Returned publishing interval in milliseconds.
  • 0 = invalid
Command.GQ uint 0 Trigger for the general query per subscription. This is triggered independent of the value.

Since a subscription can be either for values ​​or alarms, the value passed is irrelevant.

Syntax for the Entry Config.NamespaceTable

Syntax 

<namespace id> <namespace name>

Example:

102 http://www.testserver.com/TestServer/
103 urn:TestServer:TestProject