I idscovered IoTaWatt a few days ago and have been reading many of the forum posts. I was having a bit of trouble understanding how the sampling rate works. As I understand it, only one channel can be sampled at any given moment. So a loop iterates over each channel, sampling one full cycle (1/60th of a second in the US) before moving to the next channel. About 650 VI pairs are collected per full cycle. The real power, apparent power, and power factor are calculated. It takes about 1/2 second to iterate over the 14 channels. The end result, for each channel, you capture 2 of the 60 cycles per second. A data point is logged for each channel every 5 seconds, which consists of the average of the last 10 samples.
Do I have this correct?
My questions are:
Are I and V measured at simultaneously or sequentially?
If I just measure the two legs of the main, would I now capture 15 of the 60 cycles per second per leg? Would the overall accuracy improve relative to a revenue grade meter? Are there any advantages to this?
Which loads are difficult (or less accurate) to measure with a 2 sample per second per channel methodology vs continuous sampling of a channel?
Thanks and feel free to educate me if I’m on the wrong track.