The IStatisticsType is an Interface to manage statistical data of any kind, and provides general information about those statistical data.
The concrete statistical data are managed in DataVariables referenced from the Object or ObjectType implementing the Interface with a HasStatisticComponent Reference, either directly or indirectly. Those Variables are not predefined by the Interface, but added by the concrete Objects or ObjectTypes implementing the Interface. In Figure 9, an example is given. The MyStatisticsType is implementing IStatisticsType and provides the statistical Variables StatVar_A and its sub-variable StatVar_A1, as well as StatX and StatY, groups by the Object StatGroup. The Property StartTime applies to all of them, as well as the Method ResetStatistics.
Figure 9 Example of the usage of the IStatisticsType Interface
IStatisticsType is formally defined in Table 38.
Table 38 – IStatisticsType Definition
|Description||Base interface for managing statistical data.|
|Subtype of the BaseInterfaceType defined in OPC 10000-5 i.e. inheriting the InstanceDeclarations of that Node.|
StartTime provides the information, at what point in time all statistical data, provided by the Object implementing the Interface, have been started to be collected. The StartTime changes when the collection of the statistical data is reset.
Note that the StartTime does not indicate, if the statistical data is aggregated from the start time, or rolled over after some specific condition. This is defined by subtypes of the IStatisticsType. Therefore, it is recommended not to use the IStatisticsType directly, but only subtypes of it.
The InstanceDeclarations of the IStatisticsType have the Attribute values defined in Table 39.
Table 39 – IStatisticsType Attribute values for child Nodes
|StartTime||-||Indicates the point in time at which the collection of the statistical data has been started.|
|ResetStatistics||-||Restarts all statistical data, including a reset of the StartTime to the current time.|
The ResetStatistics Method resets all statistical data provided by the Object implementing the Interface. That includes, that the StartTime is reset to the current time.
The signature of this Method is specified below. The Method does not have Input- or OutputArguments.
ResetStatistics ( );
Method Result Codes (defined in Call Service)
|Bad_UserAccessDenied||See OPC 10000-4 for a general description.|
Its formal representation in the AddressSpace is defined in Table 40.
Table 40 – ResetStatistics Method Definition