5-12
Making Measurements
To use the Roll horizontal mode
To use the Roll horizontal mode
•Press the Main/Delayed key, then press the Roll softkey.
Roll mode causes the waveform to move slowly across the screen from right to
left. It only operates on time base settings of 500 ms/div and slower. If the
current time base setting is faster than the 500 ms/div limit, it will be set to
500 ms/div when Roll mode is entered.
In Normal horizontal mode, signal events occurring before the trigger are
plotted to the left of the trigger point () and signal events after the trigger
plotted to the right of the trigger point.
In Roll mode there is no trig ger. The fixed re ference poi nt on the scre en is the
right edge of the screen and refers to the current moment in time. Events that
have occurred are scrolled to the left of the reference point. Since there is no
trigger, no pretrigger information is available.
If you would like to clear the display and restart an acquisition in Roll mode,
press the Single key.
Use Roll mode on low-frequency waveforms to give a display much l ike a strip
chart recorder. It allows the waveform to roll across the display.