The Analog Discovery's Voltmeter uses the oscilloscope channels.
When the Voltmeter is enabled, it takes control over the two physical
oscilloscope channels and the Oscilloscope instrument state is "busy".
Similarly, when the Oscilloscope is started, the Voltmeter is disabled.
The DC
voltage value is computed as an average of 0.2 seconds of oscilloscope
acquisition.
For the True RMS, value the same acquisition is used as for the DC voltage, and the value is calculated with the formula Sqrt( sum( xi ^ 2 ) / N ).
The AC RMS value is calculated with the formula Sqrt( sum( (xi - dc) ^ 2 ) / N ).
When the measurements are close to the range limit, a question mark (?) is displayed in front of the value, suggesting that the measurement is erroneous.
The two ranges cover the +/- 25V range for both single and differential measurements. See Oscilloscope for more information.
The Auto Range option allows the measurements to be scaled according to the limit values of both ranges.