Rigol MSO8104

RIGOL Chapter 4 To Set the Sample System
4-12 MSO8000 User Guide
After you select "User", press Expand User and then rotate the multifunction
knob to set the expansion reference. Its available range is from the
rightmost position of the screen to the leftmost position of the screen. By default,
it is the screen center. Pressing down the multifunction knob can quickly
reset the user-defined reference position to 0.
Note: This function is unavailable in YT mode with the delayed sweep being enabled,
XY mode, and ROLL mode.