Hi All,
I am thinking of using the
ACPL-C87B for measuring inverter voltage (both DC and AC). In the technical manual, there is a typical application circuit (shown below).
![](https://www.eevblog.com/forum/projects/measuring-voltage-using-acpl-c87b-question-about-grounding/?action=dlattach;attach=2337573;image)
Pin 4 is connected to the GND and the bottom side of the voltage divider.
However, if I am measuring line-to-line voltage (Vab, Vbc, and Vca), then in each of these cases, my 5V DC GND will be connected to the line voltage potential. Similarly, for DC measurements, with a grounded mid-point, the negative DC rail will be at -1/2 DC voltage.
Basically, my voltage divider schematics will look like this, with both L1 and L2 at the high(er) voltage, e.g., 230 Vac RMS and 680 Vdc, but the ACPL-C87B says connect analogue PCB GND to L2.
![](https://www.eevblog.com/forum/projects/measuring-voltage-using-acpl-c87b-question-about-grounding/?action=dlattach;attach=2337581;image)
Is it possible to use the ACPL-C87B to measure AC voltages? And how should my connection between L1 and L2 and the input pins to the voltage sensor look?
Kind regards, MB