Overview
A HistorianTag represents a specific data point you want to track and store over time. The HistorianTags definition links a Tag to a HistorianTable for organized storage, supporting various data types. When you map the tag to a HistorianTable, it will record the value changes or events associated tag over time.
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Understanding HistorianTags
When a solution Tag, or an external Asset, is mapped to be archived or retrieved from an Historian, that configuration is called a HistorianTag.
When you define HistorianTags, you archive data by associating information with specific tags and HistorianTables in Storage Locations. In other words, you establish a link between Tags and HistorianTables to ensure systematic and organized data storage.
When archiving Tags created using DataTemplates, you don't need to specify all the properties.
The two pieces of Information that are mandatory to define an Historian Tags are:
TagName: variables that will archived, or retrieved.
HistorianTable: logical object that groups data and defines the storage location to which that variable will be connected.
Configuring HistorianTags
Before setting HistorianTags, you need to configure the HistorianTables. However, you can use the default one (Table 1).
After configuring the HistorianTables, you can start defining which Tags to archive with the configured HistorianTables. To add and configure a single Tag, follow the steps below:
Access Historian → Historian Tags.
On the TagName column, type the Tag name or select from the available list. Alternatively, copy and paste the Tag's name from Unified Namespace → Tags.
Configure the DeadBand, Deviation, and RateOfChange. The following section describes each of these configurations.
Select if the platform should consider an Absolute or Percentual as the DeviationDeadBandType.
To finish, select the HistorianTable, where the Tags' information will be archived.
The image below illustrates the process described above.
HistorianTags Properties
When configuring a HistorianTag, you need to specify some properties that will define how data will be archived. The following table describes each available property you can configure:
| Property | Description |
|---|---|
TagName | Specify the unique identifier of the Tag to be archived. To archive Template Tags, specify one of the Template Tag's properties or archive all properties by entering only the primary Tag name. |
DeadBand | (Optional feature) Defines how much the value must change (in Units) for the system to store the value. This configuration is considered when you use the SaveOnChange option in the HistorianTable. |
Deviation | (Optional feature) Specify how much the value must change (in Units) for the system to store the value. This configuration is considered when you use the TimeDeadBand option in the HistorianTable. If you define this property, its value overrides the TimeDeadband logging interval. |
RateOfChange | (Optional feature) Defines how much the value must change (in Units) by second for the system to store the value. This configuration is considered when you use the TimeDeadBand option in the HistorianTable. If you define this property, its value overrides the TimeDeadband logging interval. |
DeviationDeadBandType | (Optional feature) Determines the calculation method used to define the Deadband value. |
HistorianTable | Select the HistorianTable to use when saving the Tag's value. |
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