Scope Multimeter
Operation and Controls
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Coupling AC
Coupling AC subtracts the average value of a signal so that small variations can be
displayed in the waveform. This is accomplished by blocking the direct current (DC)
portions of a signal in order to amplify (show) the alternating current (AC) portions
of the signal, without driving the trace off of the screen.
Using coupling AC can be helpful when testing and diagnosing alternator ripple or
fuel pump amperage, by allowing you to see any abnormal small variations or
events.
To turn coupling AC on and off, select the
Coupling AC
icon.
Trigger
NOTE
The Trigger feature is only available in the lab scope function.
A trigger can be used to stabilize a changing or erratic signal (a signal that may
flicker or drift as it refreshes), so that it is easier to view or diagnose. This
stabilization effect is accomplished by basically displaying the same part of the
trace repeatedly from the same starting point, thus the flicker or drift is minimized
which makes the trace appear more consistent or static.
A trigger is basically a “specific point” on the display, at which a trace will start to
display (start the sweep) if it crosses that point.
The trigger feature allows you to set the conditions of that “specific point” also called
a “trigger point”. When the trigger conditions are set, and a trace “meets” those
conditions (crosses the trigger point), the trace will start.
Trigger conditions:
•
Vertical scale position (amplitude)
•
Sweep position - the horizontal scale position, or position in time
•
Slope direction
- the direction the trace must be moving (up/rising or positive)
or (down/falling or negative) when crossing the trigger point.
NOTES
Triggers can be set on any channel, however only one trigger can be activated
(used) at a time.
If a trigger is set outside the range of the scales, a yellow marker (e.g. arrow
with plus symbol) will be displayed (
) indicating the trigger is out of
range and a confirmation screen will display.
When a trigger is set on a channel, and more than one channel is active
(displayed), trigger conditions must be met for that channel in order to display
all the other channels.
z
To turn a trigger on/off:
A trigger is activated by selecting the trigger icon from the control panel, which
then automatically initiates trigger slope setup.
1.
Select the desired channel’s
Trigger
icon.
Each tap of the icon sets the trigger to a different slope setting, or turns the
trigger off.
2.
Select the desired slope setting, to turn the trigger on.
3.
Proceed to
“To set trigger position”
next to complete the trigger set up.
Coupling AC Icons
On (DC signal portion blocked)
Off (DC signal portion not blocked)
Trigger Icon
Description
Rising (up or positive)
- Trigger is turned on to start the trace on the
rising edge (as signal begins to rise)
Falling
(down or negative)
- Trigger is turned on to start the trace on
the falling edge (as signal begins to fall)
Off
- Trigger is turned off.
