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How to obtain RMS current, voltage, and power readings in volts, amps, and watts.

Question asked by dkozicki on Oct 13, 2016
Latest reply on Jan 18, 2017 by dlath

We have a ADE7953-Eval circuit board with its USB interface and Windows GUI.  I'm trying to use the ADE7953 as a power meter to read real world values for RMS voltage in volts, current in amps, and power in watts directly from the IC's internal registers.  We want to use the ADE7953 to monitor and industrial process and make Apparent Power and Active Power measurements.  We aren't using Reactive Power measurements or the Watt-Hour function. 


We are using the ADE7953's current channel A with a 0.001 ohm shunt.  Our current range is 0.5 to 30 amps RMS.  I assume an input amplifier gain of 2 is a good setting.  We are using a 1/1000 voltage divider for the voltage channel.  Our voltage range is a 1 to 250 volts RMS.  I assume an input amplifier gain of 1 is a good setting.  Given our primary power interface and gain settings, it would be useful to have knowledge of what the IRMS Register step size as a function of the AIGAIN Register setting and the IRMS Register's maximum count.  We need the same information for VGAIN and VRMS registers.


Reading power in watts is interesting.   I see the AWGAIN Register as the input to 49 bit accumulator with FIXED INTERNAL THRESHOLD to the AENERGYA Register sampled by a function of the LINECYC Register.  I want to use this part of the IC to read watts.


Please help me with register settings for the ADE7953.