Archiving and Compression
Compression is used to minimize the large amount of historical data. For instance, only daily or weekly averages are of interest after a certain period of time. In this case, average values are archived first hourly. Then weekly or monthly averages are calculated from these and archived. This makes it easier to obtain an overall picture of the data.
Convenient Compression panels are provided for space-saving and time-saving archival of values. You can perform the following actions in these panels:
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Specify several compression levels having different intervals, for example, calculate the 5-minute average, then calculate an hourly average from this and this, in turn, is used to calculate a daily average.
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Define compressions of data points using statistical functions in the data point type.
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Assign the data point type settings to your selected data points with a click of the mouse.
Advantages:
You can make or amend your settings in the data point structure and apply them to all required data points with a click of the mouse.
You can use these data points as type references and attach them to other data points.
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AC type (from Archive and Compression): These data point types are created from scratch. You can perform compression and archiving in these data point types. The data point types have a predefined structure containing fixed structural elements and variable structural elements defined by configuration (see Structure of AC types). The data points adopt the complete compression structure.
The dedicated configuration panels simplify the creation of new data point types and data points, as well as compression and archive configuration.
| Chapter | Content |
|---|---|
| Archiving and Compression, basics | Purpose of archiving and compression of data points |
| Before compression | What needs to be considered when selecting an archive? What data is relevant? |
| Compression configuration panels | How to access the panels? What panels are relevant? |
| AC configuration panel | Main panel for compression configuration, the buttons and their function. |
| DPT configuration panel | In this panel, you can select "exception" data points and apply the structure to the data points. |
| Configuration panel AC type | For setting the compression parameters for AC types and contains the compression intervals, archives and functions. |
| Configuration of an AC type | Worked-through example for a data point type with three compression levels created from scratch. |
| Details on AC configuration | Details of the internal data point type _AcStructure |
| Summary and relevant links | Summary and links to other relevant chapters |
