It looks like all the 24-bit instantaneous waveform data, peak detection values and over-voltage thresholds are all after the VGAIN register. Is this correct?
I'd like to derive an formula for converting raw 24-bit values to real world voltage readings at the input to my meter. The datasheet tells me an approximate way of doing it is:
reading/5,989,256 * 0.5V * D
where D is my meter's voltage divider ratio, but this is subject to the variations in my 1% resistor divider.
I've used precision equipment to calibrate VGAIN so the the 7816's VRMS readings give me real world values. 1 LSB of the VRMS represents 62.5uV (1/16th of a mV) at the input to my meter. Given I've done that, it seems it must be possible to come up with a formula to convert a raw 24-bit voltage reading to a real-world voltage also.
Maybe some real live numbers will help explain what I'm after:
My resistor divider is 880K/1K
I've configured a voltage gain of x 1.2108 (i.e. the VGAIN register is written with 0x1afd11)
Now 234V RMS ideal input to my meter gives me a VRMS(*) reading of 3,744,000
Then I configure VPEAK detector to give me the peak over 255 half cycles.
A typical VPEAK reading I get back is 5,253,231
I'm looking for a way to calculate what divider I should use to turn that back into real world volts at the meter input. Empirically I can determine that the answer must be about 15,874, i.e 5,253,231 / (234 * sqrt(2)), but it seems that given I've used VGAIN to turn VRMS into real-world units, I should be able to calculate what I need to do to turn a raw 24-bit value into real-world units as well. Is it as simple as dividing by 16,000?
(*) All VRMS readings are done via the recommended large averaging technique to remove any ripple.