D100 vs D120 - Different voltage readings

[Alfio]

I have a D10, D100, and D120 system. When reading the system voltage I obtain the following:
D10 14.5
D100 14.6
D120 13.8 to 14.2

How does each unit measure the battery/alternator voltage? Is it per the supply to each box (e.g. power pin to the D10 measures D10 voltage w.r.t. ground pin)? Does the D120 measure the voltage as sampled by the current sensor, or does it utlilize the power pin and ground pin of the D120?

Are any of the voltages shared via the DSAB?

Thanks.

Alfio

 

[Dynon]

The EMS-D10 and EMS-D120 both use the power input pin on the D37 connector. Similarly, the EFIS-D100 uses its power input pin on the D25 connector. The current sensor/shunt isn't part of the voltage measuring equipment.