Internal data points of the OPC UA server

The WinCC OA OPC UA server uses on central data point of the type _OPCUAPvssServer for the general status displays and the configuration parameters. The name of the data point is by default OPCUAPvssServer. The manager number is not part of the name, as typically only one OPC UA server is present in a project and this can be started with an arbitrary manager number. The name of the data point can be set in the config configuration file (see Possible Config Entries for the OPC UA Server).

_OPCUAPvssServer

Data point element Type Description
Config.EnableLogging uint

Activates the logging in the OPC UA SDK (= UaTrace).

No logging = 0 (default)
Config.DisableDataUpdate uint

If DisableDataUpdate is set to 1, no data values are updated in the OPC UA process space. In case that the values change in the WinCC OA project, the value is marked as "Uncertain" in the OPC UA process space.

If the data point element is reset to 0 current values are transmitted to the client, without any activity on client side.

Default value = 0
Config.DisableWrite uint If DisableWrite is set to 1 the UA server does not allow write requests by the client and returns the error code WriteNotAllowed. By setting DisableWrite to 2 it is possible to silently discard the write request without any error on the client side.
Config.CNSViews dyn_string This data point element contains all CNS views which are linked to the server for creating the address space.
Config.GroupAuthentication dyn_uint Group authentication can be enabled via this data point element. Per default this element is empty, which means group authentication is not active. If you define group IDs, in addition to the user authentication the server cecks whether the specified user is a member of at least one of the defined groups.
Config.AlarmPrioMapping dyn_string

This data point element contains all configured assignments of WinCC OA alert classes to OPC UA severities.

Whenever the OPC UA server receives an alert from WinCC OA, it looks for configured severities. If a severity is configured for the alert class, the alert is forwarded using it, otherwise the WinCC OA alert priority is used as OPC UA severity.

The list contains one entry for every assignment in the format <alert_class> <severity>.
Config.StatusMapping dyn_string

This data point element contains all configured assignments of user bits to OPC UA status codes.

Whenever the value of the server data point element changes, it checks for mapped user bits. When a user bit with an assigned status code is set, the server forwards the value change with the status code. If there are multiple user bits with an assigned status code set, the highest one will be used.

The list contains one entry for every assignment in the format <user_bit> <status_code>.
Config.DatapointLogging bit32

This data point element is used to enable or disable datapoint logging.

Session Logging
Setting bit 1 to TRUE enables Session Logging, which logs whenever a client connects or disconnects on the data point element State.DatapointLogging.Session.
Write Logging
Bit 2 activates Write Logging, which logs all value changes performed by clients on the data point element State.DatapointLogging.Write.
Method Logging
Bit 3 activates the logging of Methods. In this case the Session ID and the Node ID of the called method are written to the data point element State.DatapointLogging.Method.
Important: The bit count starts with 1.
Tip: The bits can be combined as needed.
Command.DebugPI bool Returns the current data point elements enabled by the OPC UA server and their UaNodeIds to the log file.
  • 0 -> no action
  • 1 -> output is carried out
Note: The debug flag "-dbg 10" is required for the OPC UA server otherwise no information is written to the log files.
State.ClientsConnected uint Number of clients connected to the OPC UA server.
State.CNSViews dyn_int

Indicates the current state of the respective CNS view.

Status Description
0 The state of the CNS view is currently not defined because the OPC server is not running. If the server has not been stopped properly (e.g. using the KILL command) the last set status remains until the OPC server is started again.
1 The distributed system is connected and the CNS view or all OPC elements of the view are correctly in the server's address space. The values of all elements in the address space are the same as the actual value of the respective data point element.
2 The distributed system is connected and a delta synchronization is running. Connected OPC clients are able to receive values from the OPC server.
3 The distributed system is connected and the entire CNS view is refreshed in the OPC server's address space (Full Sync). In this case, connected OPC clients receive the last usable values from the OPC server, which are marked with OPC quality "Uncertain, Last Useable Vale". If one CNS view of a system is in Full Sync state, all other CNS views will be in this state also.
4 The distributed system is connected, but the configured CNS view does not exist or cannot be found in the given system.
5 The distributed system is not connected and the server does not have any information about the configured CNS views in the address space. As soon as the distributed system is connected, the OPC server does a full synchronization for all views.
6

The distributed system is not connected, the OPC server has IP identification and CNS views in its address space. The server marks all values of the system of the CNS view with OPC quality status "Uncertain, Last Usable Value". If the connection to the distributed system is established, the OPC server starts a full or a delta synchronization depending on config entry maxUpdateMsgCouint and the amount of changed data.

If the OPC server is started with useLocalIdentification, the address space will be created with the information loaded from the files proj_path/data/DpMsgTypeContainer.bin and proj_path/data/DpMsgIdentification.bin, so TypeContainer and DpIdentification must not be transmitted over the network.
State.MaxNumberOfClients bool

Indicates whether the maximum number of client connections has been reached.

TRUE = maximum number reached

FALSE = maximum number not reached
State.DatapointLogging.Session string

This data point element is updated whenever a client connects or disconnects from the server.

It contains messages in the format:

<hex session id> <code> “<session name>” “<authentication method>” “<username>” <hex ua status code>

For more information see Enable Session Logging.

This data point element is only updated when Session Logging is enabled on the data point element Config.DatapointLogging.
State.DatapointLogging.Write string

This data point element is updated whenever an OPC UA client changes values.

It contains messages in the format:

<hex session id> <UA node id> <new value> <hex ua status code>

For more information see Enable Write Logging.

This data point element is only updated when Write Logging is enabled on the data point element Config.DatapointLogging.
State.DatapointLogging.Method string

This data point element is updated whenever an OPC UA Method is called.

It contains messages in the format:

<hex session id> <UA node id>

For more information see Enable Method Logging.

This data point element is only updated when Method Logging is enabled on the data point element Config.DatapointLogging.