The Data Historian stores timestamped data samples taken from:
You can display data from the Data Historian in a Trend Plot:
You can display data from the Data Historian in a list:
You can configure which tags store values in the Data Historian using the HistoricEnable property. This property can be set separately for each Data Point Tag and Time Series Tag.
HistoricEnable | Description |
---|---|
False | No data samples from the tag is stored in the Data Historian. |
True | Data samples from the tag are stored in the Data Historian. |
Note: If you change HistoricEnable from True to False, the existing data samples are retained in the Data Historian.
Third party applications can access the Data Historian from these interfaces built in to Fernhill SCADA:
Each Tag stores its data in a separate named data table. To find the name of the data table for a tag, read the value of the HistoricDataTable property.
You can query a historic named data table directly. For example:
SELECT ValueTime AS "Time Stamp", ROUNDSD( Value, 4 ) AS "Value", QUALITY_TO_STRING( Quality, TRUE ) AS "Quality", LOG_REASON_TO_STRING( LogReason ) AS "Log Reason" FROM Historic000014 WHERE ValueTime >= Current_Timestamp - Interval '1' Day ORDER BY ValueTime DESC FETCH FIRST 250 ROWS ONLY
The Data Historian provides a set of views for querying all historic data of a given type:
View Name | Description |
---|---|
HistoricDataViewBOOL | Historic data for Digital Data Point Tags. |
HistoricDataViewLREAL | Historic data for Analog Data Point Tags. |
HistoricDataViewTIME | Historic data for Time Series Runtime Tag. |
HistoricDataViewUDINT | Historic data for Double Word Data Point Tags. |
HistoricDataViewUINT | Historic data for Word Data Point Tags. |
HistoricDataViewULINT | Historic data for Long Word Data Point Tags and Time Series Counter Tags. |
HistoricDataViewWSTRING | Historic data for String Data Point Tags. |
You can use an INNER JOIN to query the historic data for a tag from a historic view:
SELECT H.ValueTime AS "Time Stamp", ROUNDSD( H.Value, 4 ) AS "Value", QUALITY_TO_STRING( H.Quality, TRUE ) AS "Quality", LOG_REASON_TO_STRING( H.LogReason ) AS "Log Reason" FROM HistoricDataViewLREAL AS H INNER JOIN TagDataPoint AS T ON T.HistoricDataTable = H.TableName WHERE T.FullName = 'Example Graphic.Tank Level' AND H.ValueTime >= Current_Timestamp - Interval '1' Day ORDER BY ValueTime DESC
To learn about other Fernhill SCADA Concepts.
To learn about the tool to configure Fernhill SCADA.
To learn about the different drivers available in Fernhill SCADA.
To learn about the SCADA Server.
To learn about integrating data into third party applications.
For the meaning of terms used in Fernhill SCADA.