Indicates how interpolation of a historized point should be handled. Valid values are "cov" and "linear":
- cov: this mode assumes the data was sampled on change-of-value. This means that interpolation should use the previous value until the next explicit change of value.
- linear: this mode is used with interval sampled data to compute the approximation using a linear equation based on the previous and next values and the associated timestamps
If this tag is not defined, then the default behavior for Bool and Str histories is to use "cov" mode and Number histories use "linear".
If a point is historized this means that we have a time-series sampling of the point's value over a time range. Historized points are sometimes called logged or trended points. Historized points should be tagged with the
If a point implements the
his tag, then it should also implement these tags:
tz: all historized points must define this tag with their timezone name (must match the point's site timezone)
hisInterpolate: optionally defined to indicate whether the point is logged by interval of change-of-value
hisTotalized: optionally defined to indicate a point is collected an ongoing accumulated value
The current status of historization is modeled with: