Rigol DS6000 Series User Manual page 111

5 To Trigger the Oscilloscope RIGOL
the knob, while at the same time, the trigger level value (e.g. ) at
the lower-left corner of the screen also changes accordingly. When stopping turning
the knob, the trigger level line and the trigger mark disappear in about 2 seconds.
DS6000 User's Guide 5-9