On my project, I use ADE7953. There are two ADE7953 on each board. Actually we treat one ADE7953 metering IC as a mete with two current channels. Channel A and B are fully independent current channel, connect to different load. For calibration, I use accurate current and voltage source.
Upon AN-1118 Application Note (Calibrating a Single-Phase Energy Meter Based on the ADE7953), Figure 4 (page 5) and Figure 8 (page 11), to calibrate current channel B energy registers, we must calibrate BIGAIN using current channel B matching procedure. My questions are:
1. I thought BIGAIN is for current gain adjustment, why should I calibrate BIGAIN for active energy calibration?
2. Does it mean current channel A must be calibrated (including AIGAIN) before channel B calibration since BIGAIN calculation is based on IRMSA and IRMSB reading, is it right? How to calibrate AIGAIN? using equation
IRMSA Expected = IRMSA initial * (AIGAIN / 0x400000)
to calcuate AIGAIN?
3. What is the primary use of AIGAIN / BIGAIN? Upon AN-1118, there is no internal gain calibration register for the rms readings, and on my application, we read IRMSA / IRMSB / VRMS value for current and voltage measurement. Does it mean I must calibrate AIGAIN / BIGAIN in order to calibrate active energy?
Thank you very much for the help.
I hope the reply to the other post(http://ez.analog.com/message/77953#77953) will be of some help.
To clarify, these gain registers are optional. But altering them will affect the entire signal path and so the energy calibration will have to be redone. Please get back if you need further information on this issue.
Yes! If you wish to match both channels, you will need to do the gain matching step first, before all other calibration steps. This will ensure that both channels have the same calibration constants and comprehending the register and CF outputs become identical. However, if that isn't of any interest to you, you may chose to skip that step and maintain the default value for those gain registers.