User`s guide

171
Using the Oscilloscope
The Scope Trigger Menu
Auto-Trig field
The Auto-Trig field allows you to specify whether or not the
acquisitions should wait for the specified trigger condition to occur.
When you select the Auto-Trig field, the field toggles between On and
Off. The On and Off fields are discussed below.
The default selection for the Auto-Trig field is On.
On
When you set auto-trigger to On, the oscilloscope waits 50 ms (20-Hz
rate) for a trigger to occur. If a trigger does not occur within that time,
the current contents of acquisition memory are displayed. The
message "Auto triggered" is displayed if one of the following conditions
occurs:
• No signal is on the input. In this case, the oscilloscope will display a
baseline.
• There is a signal but the specified trigger condition has not been met
within 50 ms. In this case, the waveform display will not be synchronized
to a trigger point.
Off
When you set auto-trigger to Off, the oscilloscope waits until a trigger
is received before the waveform display is updated. If a trigger does not
occur, the screen is not updated and the message "Waiting for Trigger"
is displayed. Use this mode when:
• The trigger source signal has less than a 20-Hz repetition rate.
• The trigger events counter (refer to "Count field") is set so that the
number of trigger events would not occur before 50 ms.
• When you want to trigger on a specific event only.