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Reg calibration of ADE 7758

Question asked by kim on Jul 1, 2014
Latest reply on Jul 14, 2014 by kim

On page 49 of the datasheet (http://www.analog.com/static/imported-files/data_sheets/ADE7758.pdf), the step 0 of gain calibration using line accumulation says that this is same as step 4 of gain calibration using pulse output. In that step 4 on page 45, there are several values which I wanted to confirm.

 

1) It has been written that set APCFNUM and APCFDEN to calculated value. Also it has been written that 'APCFNUM is written to 0 or 1'. But APCFNUM is a 16 bit register. So by the previous statement do you mean that all bits are either 1 or 0?

 

2) How do you calculate the value of MC i.e. Meter Constant?

 

3) Also like I(test) is the test current, similarly V(NOM) is the test voltage, right? [ I am confused by the statement 'V(NOM) is the nominal voltage at which the meter is tested'. Hence, I wanted to confirm.']

 

4) On pg 50 of the datasheet, step 6, it is written that 'calibrate watt and VA simultaneously and first'. What is meant by this?

Aren't all the steps for calibration? Can someone confirm that this step requires only setting up the test system or something else?

 

One last minor doubt: In my project, I am using the values of only the WATTHR registers. Hence its ok if I don't do the calibration steps for xVAHR, right?

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