Slope retrieval

Slope retrieval returns the slope of a line drawn through a given point and the point immediately before it, thus expressing the rate at which values change.

This retrieval mode is useful for detecting if a tag is changing at too great a rate. For example, you might have a temperature that should steadily rise and fall by a small amount, and a sharp increase or decrease could point to a potential problem.

The slope retrieval mode can be considered a delta mode. Apart from the initial value and a value at the query end time, all returned points are calculated delta points returned with the timestamp of an actual delta point.

Slope retrieval only works with analog tags. For all other tags, normal delta results are returned.

All returned values are in chronological order. If multiple points are to be returned for a particular timestamp, they are returned in the order in which the tags were specified in the query.