I'm using the EV-ADE9153ASHIELDZ Evaluation Kit along with the supporting example Arduino code. In addition, I'm also using the equivalent of MTE's PTE 400 to source current to the IAP/IAN inputs and I haven't modified the board at all, so the WSK12161L000FEA, 1m-ohm shunt, is still present. I do not provide the line voltage for measurement.
My goal is to get the datasheet accuracy of 0.2% (or at least <1%) after using mSure to calibrate. In theory, I should be able to compare the output of the MTE's PTE with the output of AIRMS. When I do this, however, I get around a 9.6% error after calibration.
All of the example code functions exactly the same, so pushing the USER_INPUT button should run calibration for runLength(t), print the values, and apply the gain to the appropriate register. I have adjusted the TARGET_AICC (which was recalculated for 1A = 838.19082 nA/code) and put the runLength to 2 minutes (but running it for a minute doesn't change the value). I'm using normal mode, though turbo mode doesn't seem to change anything. I also ensure that the 1A current is applied before running calibration.
The only variable I can tell is that the reported temperature is different between my tests. I can't find anything about mSure compensating for the measured temperature, but this is the only theory I have at the moment. I'd be happy to provide any information I can.
P.S. I have some other questions, feel free to answer if they're obvious. The accuracy is most important
- The TARGET_AICC seems arbitrary if the user can define whatever value they want for the headroom. With that being said, TARGET_AICC is used all over the place in the code and seems very important. What if the user doesn't change this value for their real system?
- I understand now this headroom is really calculated from the shunt value + gain and isn't arbitrary
- If I do not have a line voltage present, what will APERIOD be?
- What is the resolution of this ADC? A lot of the calculation constants seem arbitrary.
Edit: Updated some of my findings.
[edited by: ColeM at 5:02 PM (GMT -4) on 22 Mar 2022]