I am using the ADE7816 to measure loads in normal AC operation, or in case of emergency battery supplied (ca. 220VDC).
I hoped not to be forced using another IC for DC measurement and so I tried my best using the bypass function of the HPF in DC operation.
The main problem I have is that I still only can use the resulting absolut value of IxRMS register. As long as the DC offset is positive I just can subtract any offset current manually from given ADE value. But if the offset is negative, I am not able to solve this. The ADE then will indicate e.g. 15mA of current measured but meaning -15mA. When I am adding the missing 15 mA the ADE will work precisely from this offset on, but before the addition makes no sense.
| current | ADEs ADC value | ADE RMS DC |
manually added offset (+15 mA) |
| 0 mA | -15 mA | 15 mA | 30 mA |
| 2 mA | -13 mA | 13 mA | 28 mA |
| 5 mA | - 10 mA | 10 mA | 25 mA |
| 10 mA | - 5 mA | 5 mA | 20 mA |
| 15 mA | 0 mA | 0 mA | 15 mA |
| 20 mA | 5 mA | 5 mA | 20 mA |
| 25 mA | 10 mA | 10 mA | 25 mA |
I totally understand that this is the main purpose of the HPF, to suppress the offsets, but in my application DC results are as important as AC results.
Is there any chance of reading a register in the ADE7816, which will give me the information of the sign of the original adc value before further signal processing was done?
Then I can check first the offset value, if it is negative or positive, then switch on the load and calculate the current correct. Thanks for any feedback and/or help on this topic.
in the features on the first page. This part is for AC measurement
