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How to calibrate ADE7953 AIGAIN / BIGAIN / VGAIN for current / voltage rms measurement

Question asked by karens on Feb 25, 2013
Latest reply on Feb 27, 2013 by hmani

On my application, ADE7953 is used. For current and voltage measurement, we read IRMSA / IRMSB / VRMS register to get rms value. To do the calibration, we use the accurate voltage source and current source.

 

For register AIGAIN / BIGAIN VGAIN, I can't find the place on both the datasheet and AN-1118 Application Note (Calibrating a Single-phase energy meter based on the ADE7953) to discuss the usage of these registers. I just wonder that under what kind of the condition should I use these registers or I could just ignore them for RMS value readings.

 

On AN-1118 (revision A), page 8, section Current and Votlage RMS using the CF OUTPUT, it states "There is no internal gain calibration register for the rms readings, and, therefore, the gain adjustment is performed in the microcontroller firmware". This is the only place on the document mentioned about these three registers although we are not use CF output to do the calibration. But on ADE7953 datasheet (revision A), page 34, section Current Channel Gain Adjustment", it gives

IRMSB expected = IRMSB initial * (BIGAIN / 0x400000)

it means I should calibrate AIGAIN / BIGAIN / VGAIN.

 

So my questions are:

1. For IRMS and VRMS reading, do I need to calibrate AIGAIN / BIGAIN / VGAIN register

2. If yes, should I use

BIGAIN = IRMSB_Expected * 0x400000 / BIGAIN_reading

to calculate the gain registers?

3. If I use two test points to calculate the gain and offset on my software, can I just set these gain registers to their default value (0x400000)?

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