Description
Expected events, such as cumulative meter resets, as well as random interruptions in data transmission, may produce abnormalities in data trends, leading to skewed statistics and falsely triggered insights. Such events can be handled using a Filter Expression Logic Block, which examines every value in the trended data and individually evaluates it against a prescribed condition, filtering the unwanted results.
Filter Expressions
Filter expressions follow the same syntax standard as Multiple Expression Logic Blocks. Visit Expression Syntax Page for more information.Some useful examples are provided below:
- Filter negative values (Output is greater or equal (GTE) to 0)
- GTE(a, 0)
- Filter negative and large values (over 1000):
- AND(GTE(a,0), LT(a,1000))
Functionality
The output of a Filter logic block is a data series such that:
- Only values that match the filter expression and their corresponding timestamps are present.
The schematic below illustrates the functionality of Filter Expression Logic Block:
