### 6 Statistical Data

### 6.2 OPC UA ObjectTypes

## 6.2.3 IRollingStatisticsType

The *IRollingStatisticsType* is a subtype of the *IStatisticsType* *Interface*. The statistical data managed by *Objects* or *ObjectTypes* implementing this *Interface* is rolling over, i.e. only a certain amount of data is considered for statistical data. It is formally defined in Table 40.

**Table 40** **– IRollingStatisticsType Definition**

Attribute |
Value |
||||
---|---|---|---|---|---|

BrowseName | IRollingStatisticsType | ||||

IsAbstract | True | ||||

Description | Base interface for managing statistical data that is rolled over, i.e. only a certain amount of data is considered for statistical data. | ||||

References |
Node Class |
BrowseName |
DataType |
TypeDefinition |
Other |

Subtype of the IStatisticsType defined in 6.2.1, i.e. inheriting the InstanceDeclarations of that Node. | |||||

0:HasProperty | Variable | WindowDuration | 0:Duration | 0:PropertyType | O |

0:HasProperty | Variable | WindowNumberOfValues | 0:UInt32 | 0:PropertyType | O |

*WindowDuration* describes the duration after the statistical data are rolled over. Only the data that were gathered during that duration are considered for the statistical data, even if the time intervals between the *StartTime* and the current time is longer.

*WindowNumberOfValues* describes the maximum number of values before the data gets rolled over. For the statistical data, only the data fitting into the number of values is considered, even if more data were gathered since *StartTime*.

An *Object* or *ObjectType* implementing *IRollingStatisticsType* shall never provide *WindowDuration* and *WindowNumberOfValues* together It shall provide a maximum of one of those *Properties*.

The *InstanceDeclarations* of the *IRollingStatisticsType* have the *Attribute* values defined in Table 41.

**Table 41** **– IRollingStatisticsType Attribute values for child Nodes**

Source Path |
Value |
Description |
---|---|---|

WindowDuration | - | The duration after the statistical data are rolled over. Only the data that were gathered during that duration are considered for the statistical data, even if the time intervals between the StartTime and the current time is longer. |

WindowNumberOfValues | - | The number of values before the data gets rolled over. For the statistical data, only the data fitting into the number of values is considered, even if more data were gathered since StartTime. |