Owon HDS272S User Manual page 35

RUN/STOP.
Check whether the trigger mode of the trigger mode menu is normal or single,
and the trigger electrical level is out of the waveform range. If so, center the
trigger electrical level or set the trigger mode to automatic. In addition, you
can press Auto to automatically complete the above settings.
7. In the oscilloscope state, the display speed becomes slower when the
average value sampling is set in the acquisition mode or the duration is
set longer in the display settings.
It is normal.
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