Extracting event frames

Since the data in the PI archive is compressed by default, the time interval between consecutive values is typically irregular. To get values at regular intervals the interpolated_values() method is used. This is available on both PIPoint, and AFAttribute objects.

For simplicity this tutorial only uses PIPoint objects, see the tutorial on PI AF to find how to access AFAttribute objects.

Basic usage

The basic example takes the first PIPoint that is returned by the server and gets the data for the last hour at 5 minute intervals, by specifying the start_time, end_time, and interval arguments to PIPoint.interpolated_values():

import PIconnect as PI

with PI.PIServer() as server:
    points = server.search('*')[0]
    data = points.interpolated_values('*-1h', '*', '5m')
    print(data)

Filtering values

To filter the interpolated values the same filter_expression syntax as for Filtering values can be used.