Here is a simple diagram of a digital circuit diagram Ammeter DMS-30PC-0-RS Solutions Murata Power. It is essentially a very sensitive voltmeter, digital ammeter with a typical input range ± 200 mV. The following circuit shows the voltage across the shunt is above 0.1 Vcc pin 3 (5V RETURN).
This figure is well below the limit of ± 2V common mode voltage meters. 0.1ohm the shunt, with 1.0 amps through it, or 100mV 0.100Vdc grows through it.