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Using the Oscilloscope
The Scope Trigger Menu
Level field
The Level field shows the voltage value of the trigger level. When the
voltage value on the trigger source input waveform equals the trigger
level voltage value, the oscilloscope triggers.
When you change the trigger level voltage value, the waveform moves
horizontally on the display to maintain the trigger point. (That is, the
point where the waveform voltage value crosses the trigger point
voltage value.)
If the trigger point voltage level is set above or below the waveform
amplitude, the trigger point cannot be found. If Auto-Trig is set to On,
this causes the waveform display to become unsynchronized and to
"float" on the display. If Auto-Trig is set to Off, the message "Waiting for
trigger" is displayed.
The trigger point voltage can be set either by the autoscale function or
by a voltage value set into the Level field. It can be set to any voltage
value contained within the waveform display window, in increments of
0.05% of full scale vertical voltage range (V/Div x 4 divisions = full
scale). For example, if full scale voltage range were 400 mV, trigger
level would be set in increments of 2 mV (V/Div = 100 mV x 4 x 0.005 =
2 mV). Values entered that are not in this range will be rounded to the
nearest 0.05% increment.