deepak4you
Member level 1
Hello Experts!
Calling out for help again while I'm in difficulty.
I'm working on a power meter setup using the ADE7763 and finding it difficult to get the correct Vrms, Vpeak, Irms, Ipeak values from the chip. I am using the attached schematic where R7+R6 = 510K, R8 = 1k. R12 and R13 are 8.8 ohms each. These are the values prescribed in the ADE7763 Evaluation Board and application note AN639 as well.
My calculation is:
1Vpp (+/- 0.5V) at ADC input (V2P and V2N) corresponds to 260Vrms/367.64Vpp at full range
ADC LSB = 1(Vpp)/10322 (ADE7763 Datasheet Page 23)
To calculate the Vpp, I read the value in VPEAK Register and do the below calculation:
Output Vpp = ADC LSB * VPEAK * 367.64
Output Vrms = Output Vpp/1.414
Similarly, for current I do the below calculations:
1Vpp (+/- 0.5V) at ADC input (V1P and V2N) corresponds to 20A of AC current
ADC LSB = 1(Vpp)/2,642,412 (ADE7763 Datasheet Page 23)
To calculate Ipp, I read the IPEAK register and do the following calculations:
Output Ipp = ADC LSB * IPEAK * 20
Output Irms = Output Ipp/1.414
I'm not getting the correct values despite these above calculations. Is there something wrong in my calculations? Or am I missing/overlooking something from the datasheet?
- - - Updated - - -
On the other hand, a very basic question as well (Apologies if this is too basic a question).
For a differential ADC, if the datasheet mentions a full scale input of 0.5V or full scale input of +/- 0.5 V, does that imply that the full range is -0.25 to +0.25 totaling to 0.5V, or, -0.5 to +0.5 totaling to 1V?
- - - Updated - - -
Reading through the datasheet further, I think I need to make corrections as below:
R7+R6 = 1M
0.5Vpp at ADC input (V2P and V2N) corresponds to 260Vrms/367.64Vpp at full range
ADC LSB (resolution) = 0.5/10322 Volts/Level (ADE7763 Datasheet Page 23)
VRMS register should directly give me the ADC code converted to RMS value.
Similarly, for current I do the below calculations:
0.754Vpp at ADC input (V1P and V2N) corresponds to 20A of AC current
ADC LSB (resolution) = 0.754/2,642,412 Volts/Level(ADE7763 Datasheet Page 23)
IRMS register should directly give me the ADC code converted to RMS value.
I wonder if these above calculations are correct for my measurement parameters?
Calling out for help again while I'm in difficulty.
I'm working on a power meter setup using the ADE7763 and finding it difficult to get the correct Vrms, Vpeak, Irms, Ipeak values from the chip. I am using the attached schematic where R7+R6 = 510K, R8 = 1k. R12 and R13 are 8.8 ohms each. These are the values prescribed in the ADE7763 Evaluation Board and application note AN639 as well.
My calculation is:
1Vpp (+/- 0.5V) at ADC input (V2P and V2N) corresponds to 260Vrms/367.64Vpp at full range
ADC LSB = 1(Vpp)/10322 (ADE7763 Datasheet Page 23)
To calculate the Vpp, I read the value in VPEAK Register and do the below calculation:
Output Vpp = ADC LSB * VPEAK * 367.64
Output Vrms = Output Vpp/1.414
Similarly, for current I do the below calculations:
1Vpp (+/- 0.5V) at ADC input (V1P and V2N) corresponds to 20A of AC current
ADC LSB = 1(Vpp)/2,642,412 (ADE7763 Datasheet Page 23)
To calculate Ipp, I read the IPEAK register and do the following calculations:
Output Ipp = ADC LSB * IPEAK * 20
Output Irms = Output Ipp/1.414
I'm not getting the correct values despite these above calculations. Is there something wrong in my calculations? Or am I missing/overlooking something from the datasheet?
- - - Updated - - -
On the other hand, a very basic question as well (Apologies if this is too basic a question).
For a differential ADC, if the datasheet mentions a full scale input of 0.5V or full scale input of +/- 0.5 V, does that imply that the full range is -0.25 to +0.25 totaling to 0.5V, or, -0.5 to +0.5 totaling to 1V?
- - - Updated - - -
Reading through the datasheet further, I think I need to make corrections as below:
R7+R6 = 1M
0.5Vpp at ADC input (V2P and V2N) corresponds to 260Vrms/367.64Vpp at full range
ADC LSB (resolution) = 0.5/10322 Volts/Level (ADE7763 Datasheet Page 23)
VRMS register should directly give me the ADC code converted to RMS value.
Similarly, for current I do the below calculations:
0.754Vpp at ADC input (V1P and V2N) corresponds to 20A of AC current
ADC LSB (resolution) = 0.754/2,642,412 Volts/Level(ADE7763 Datasheet Page 23)
IRMS register should directly give me the ADC code converted to RMS value.
I wonder if these above calculations are correct for my measurement parameters?