MEAS:VOLT:DC? starts a new measurement and then queries the DC voltage.
FETC:VOLT:DC? queries the DC voltage without starting a new measurement.
The valid modes (parameters to the OUTP:COUP command) are DC, ACDC (PCR-M only), and EDC (PCR-M only).
Returns the DC voltage in NR3 format in response to MEAS:VOLT:DC? or FETC:VOLT:DC?.
In case of the single-phase three-wire output, MEAS:VOLT:DC? or FETC:VOLT:DC? returns a comma-separated list of the DC voltage <NR3> for U and V phases.