The power recorders use an "observation period" for flicker that is 10 minutes for monitoring intervals of that are at least 24 hours, and not more than 1 month. In intervals of that length, you would see the 10 minute Pst readings you expect. But in the shortest and longest monitoring intervals, it is adjusted for better accuracy. Here is a chart that tells what the Pst readings will cover..
PLT is calculated over 12 datapoints in all cases, so in the case of a one hour monitoring period, 12 points (each 30 seconds) gives a PLT reading every six minutes, or 10 in an hour.
Note: This web page does not form part of any official documentation.
© M.T.P. - 16.12.02