ARDI Historian Behaviour
It's important to note that the options that effect the resolution of your historical data are only guidelines. The actual data returned may have far more or fewer samples than what you requested.
This is for several reasons…
Data Resolution
If your data is at lower resolution than you requested, drivers will not pad the data.
Detail Preservation
Some data sources - such as Aveva PI - have intelligent queries that help retain fine detail in complex data and result in very few samples when the process is 'quiet', and dense clusters of samples during periods of activity.
Discrete Data
When ARDI requests data, it asks for discrete information (ie. on/off values, machine statuses etc.) as raw data - no interpolation happens. This ensures that all analytics that work with conditions or timings (ie. OEE calculations) have accurate results.
If you need time-synchronised data across multiple points, we suggest using ARDIs AQL API, which can provide a single table containing time-synchronised data points.