The Analog Discovery's Meter uses the oscilloscope channels.
When the Meter is running, it takes control over the two physical oscilloscope channels and the Oscilloscope instrument state is “busy”. Similarly, when the Oscilloscope is started, the Meter is stopped.
The oscilloscope sweeps are windowed and DC, AC and DC RMS values calculated.
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 ).
The history plot has the following components:
For each channel, the color and scaling option can be specified: auto scaling based on the extremes from the plot history or manually specified offset and range.
See Export in Common Interfaces.