What are the conditions that will cause the U1270 series handheld multimeter to display Incorrect DC Voltage values at DC measurement mode when signal

The incorrect value may occur if the Filter (LPF) is not enabled for DC measurement mode, with AC’s Vpeak has exceeded the 3 times of the full-scale range. For the 1000 V range, it is 1.5 times of the full-scale range.

Example: A mixed signal with 40 Vac 50 Hz and 2.6 Vdc is measured at 3 V range.
At 3V full scale, Vpeak =3×Vrms (full scale) = 3 × 3 V = 9 Vp
The peak value of the 40Vac has exceeded the 9 Vp even though the DC is 2.6 Vdc. The AC component has to be within the 9 Vp for an accurate DC Voltage value at 3V range.

Users are cautioned to turn on the filter at all times when making DC voltage measurements for mixed signal.