The purpose of this document is to explain the differences between Sample rate, Trend Interval, Demand Interval and Duration for the Fluke-1732, 1734,1736 and 1738.
Sample Rate: The sample rate is 10,240 samples per second. The instrument uses that sample rate all the time to calculate ½ cycle RMS voltage and amperage measurements. The RMS calculations such as Volts, Amps, kW, kVA, kVAR, PF and Harmonics are calculated at the ½ cycle rate (8.33ms for 60Hz systems).
Trend Interval: The Trend Interval is used to gather data over that time period and draw graphs and store RMS readings. As an example if you are logging volts and choose an average interval of 1 minute the instrument will gather ½ cycle readings over 1 minute per phase (7200 values) and keep the maximum value, minimum value and calculate the average value.
Demand Interval: The demand interval is only used to gather data related to energy (kWH).
Duration: The duration is the amount of time you program the instrument to log data and will stop gathering data when the duration has been met. You can stop the instrument before the duration is met.