Stumbled across the Analog Devices ADE7763 IC. It is a chip dedicated to single phase energy monitoring. It has inputs for current and voltage sensors. The chip takes these values, computes the RMS values, takes the product, and integrates it over time to compute energy usage. The results (and many of the intermediates) are available over an SPI bus.I purchased two and some prototype adapter boards to go from SMT to DIP format. I started to interface it to an Arduino and get the rather strange SPI interface working. This chip has different sized transfers based on the address. Some addresses are 8 bits, others are 16, or 24. Makes a generic interface a nuisance.
I seem to have gotten the interface to work, but the chip is currently useless as it needs a strange value crystal I do not have. Placed a DigiKey order that took forever to arrive because the order included two lithium coin cell batteries that can’t go by air. The mule dropped them off at my house yesterday. Soon I will try to measure the RMS capability with a sinusoidal signal generator as an input. This chip looks real nice.