Horizontal Control
28
To change the time base for the zoom window, turn the Horizontal Scale Knob. The
Horizontal Position Knob
sets
the left- to- right position of the zoom window.
The delay value, which is the time displayed relative to the trigger point is momentarily displayed in the upper right
corner of the display when the
Horizontal Position Knob
is turned. Negative delay values indicate you’re looking at a
portion of the waveform before the trigger event, and positive values indicate you’re looking at the waveform after the
trigger event.
To change the time base of the normal window, disable
Zoom
, then turn the
Horizontal Scale Knob
.
4.3 Roll Mode
In
Roll
mode the waveform moves slowly across the screen from right to left. It operates on time base settings of 50
ms/div and slower. If the current time base setting is faster than the 50 ms/div limit, it will be set to 50 ms/div when
Roll mode is entered.
In Roll mode there is no trigger. The fixed reference point on the screen 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 pre- trigger information is available.
To enter
Roll
mode press the
Roll
button.
To stop the display, press the
Run/Stop
button.
To clear the display and restart an acquisition in Roll mode, press the
Run/Stop
button again.
To exit
Roll
mode press the
Roll
button.
Note:
Use
Roll
mode on low- frequency waveforms to yield a display much like a strip chart recorder.
4.4 Trigger Delay
Turn the
Horizontal Position Knob
on the front panel to adjust the trigger delay of the waveform. During the
modification, waveforms of all the channels would move left or right and the trigger delay message at the upper-right
corner of the screen would change accordingly. Press down this knob to quickly reset the trigger delay.
Changing the delay time moves the trigger point (solid inverted triangle) horizontally and indicates how far it is from the
time reference point. These reference points are indicated along the top of the display grid.
All events displayed left of the trigger point happened before the trigger occurred. These events are called pre- trigger
information, and they show events that led up to the trigger point.
Everything to the right of the trigger point is called post- trigger information. The amount of delay range (pre- trigger
and post- trigger information) available depends on the time/div selected and memory depth.
The position knob works (in Normal time mode) while acquisitions are running or when they are stopped.
