Data quality rule types

The data quality rules should support the following:

1. Data presence - Identify whether defined data channels exist with at least one point. Used to identify whether data is arriving at all.

2. Data lag - for datetime stamped data types only, computed based on NOW-datetime of received data point. Used to identify data streams that have stopped and are now stale.

3. Data sampling frequency - computes the time between samples. Used to identify when the sample rate is not as required or when there is a gap larger than acceptable.

4. Domain range - Compares the data point value to defined range values. Used to identify when the data point lies outside the expected technical range of the measurement.

The trigger values for these should be the basis for the default sample excel sheet.