Hello , Hmani,
After al long time I got back into project,
Now I have added ferrite beads to the filter networks.
I tried calibrating the meter.
Even after calibrating the meter there was a error in linearity of the RMS register values. I have included the values below.
I calculated ideal value with the equation Irms = (In/Ifs) * 4191910
In = I nominal
Ifs = I full scale ( calculated with CT ratio)
| current (A) | measured | ideal value | difference |
| 5.1 | 182,097.00 | 199,558.00 | (17,461.00) |
| 10 | 468,000.00 | 391,291.00 | 76,709.00 |
| 20.3 | 900,000.00 | 794,322.00 | 105,678.00 |
| 30.2 | 1,407,000.00 | 1,181,701.00 | 225,299.00 |
The difference between ideal value and measured value increases with the current I am measuring.
I solved that problem for a range of 1A to 10A by calibrating RMS current offset calibration registry. For AIRMSOS registry value , I used 1A as Imin and 10A as Inominal.
The power meter should be able to accurately display a minimum current of 0.1A
The Ideal output code for 0.1A is 3912 but the meter shows a value of 6000 because of noise.