Uncertainty

What is Uncertainty?

Uncertainty describes a point in time past which the values of a signal or condition might change. Generally this is a point close to the present time. This appears on the trend as dashed lines for signals and hollowed-out capsules for conditions.

Data from the region of time that is uncertain is referred to as Uncertain Data.

Future values are uncertain. Signals or conditions that depend on uncertain parameters will have uncertain regions that depend on the sources and the calculations.

Uncertainty from Historians

Data exception reporting and compression testing are methods used by historians to evaluate incoming data and store only data points that are determined as meaningful. This practice maximizes historian efficiency by reducing drive space needed to store data and by minimizing unnecessary signal noise. The result is that the most recently reported data point may or may not be stored permanently in the historian. Seeq can read this data point from some historians but does not know if this point will remain stored in the historian or be filtered out via exception reporting or compression testing. This data point is regarded as uncertain by Seeq along with any calculated items using this uncertain data.

For more information on Data Exception and Compression, check out this video by OSIsoft.

How does Uncertainty change from calculations?

A Seeq calculation often inherits uncertainty from its most uncertain input. For instance, if you intersect two conditions, the resulting uncertainty is based on the more uncertain of the inputs.

Certain functions will increase uncertainty in relation to the maximum interpolation or maximum duration of the functions inputs. See Interpolation.

Some inputs define a training window or a lookback period and uncertainty can be correlated with the size of these inputs.

Hide Uncertain Indicators

If you do not want to see dashed lines or hollow capsules in the trends when uncertain data is present, use the Certainty button in the toolbar. This allows you to change the visual representation without changing the underlying data.

It is important to note that hiding the region of uncertainty for a signal and/or condition will not make that region certain.

Inserting Content

In Organizer, the option to hide certainty exists when inserting a piece of content. Select a value from the Certainty dropdown. This option is also available when editing inserted contents in bulk.