Front Panel Operation
2-46
source selections, the trigger pulse is available at the
METER COMPLETE connector.
In the Measure Layer, the output trigger is always enabled
and occurs after every device action. If the control source is
set for external, immediate, manual, GPIB or timer, the out-
put trigger pulse is available at the METER COMPLETE
connector. If the trigger link (triglink) control source is
selected, output trigger action occurs on the selected TRIG-
GER LINK output line as follows:
• If the asynchronous Trigger Link mode is selected, the
output trigger pulse is available on the programmed
output line.
• If the semi-synchronous Trigger Link mode is selected
and the source bypass is disabled, the Trigger Link line
is released (goes high).
• If the semi-synchronous Trigger Link mode is selected
and the source bypass is enabled, the Trigger Link line
is pulled down low and then released.
Counters —
All three layers use programmable counters
which allow operation to return to or stay in the respective
layer. For example, programming the Measure Layer counter
for infinity keeps operation in the Measure Layer. After each
device action and subsequent output trigger, operation loops
back to the Trigger Layer control source. A counter resets
when operation loops back to a higher layer (or idle).
2.7.2 Configuring the measure layer
The measure layer is used for the following operations:
• To select the measuring event (SOURCE) for the instru-
ment.
• To delay operation in the measure layer.
• To designate the number of measurements the instru-
ment will make (COUNT).
• To enable or disable the Source Bypass.
The measure layer is configured from the MEASURE item
of the CONFIGURE TRIGGER menu, which is displayed
by pressing the CONFIG key and then the TRIG key. Gener-
al rules for navigating through the menu structure one con-
tained in paragraph 2.3.4.
SOURCE
This menu item selects the event that controls the measure
source.
IMMEDIATE:
With this selection, events (such as TIMER
and EXTERNAL triggers) do not control the measurement
interval. Once the Model 2002 starts measuring, it will take
readings as fast as its measurement configuration allows.
EXTERNAL:
With this selection, external triggers are used
to control the measure source. Each trigger stimulus applied
to the Model 2002 performs a device action, as defined by
the trigger model. In addition to a measurement, this may
include range changing, filtering, calculations, data storing,
scanning, and other operations.
The external trigger is applied to the rear panel “EXTER-
NAL TRIGGER” BNC connector. See paragraph 2.7.6 for
detailed information on external triggering.
NOTE
The front panel TRIG key (see MANU-
AL) is active with external triggering se-
lected. Pressing the TRIG key performs a
device action.
MANUAL:
With this selection, the front panel TRIG key
controls the measure source. A device action is performed
when the TRIG key is pressed.
NOTE
The front panel TRIG key is active when
EXTERNAL, GPIB, TRIGLINK, or TIM-
ER is selected.
GPIB:
With this selection, bus triggers control the measure
source. When the Model 2002 receives a bus trigger (GET or
*TRG), it performs a device action, as defined by the trigger
model. In addition to a measurement, this may include range
changing, filtering, calculations, data storing, scanning, and
other operations. See Section 3 for detailed information on
bus triggers.
NOTE
The front panel TRIG key (see MANU-
AL) is active with bus triggering selected.
Pressing the TRIG key performs a device
action.
TRIGLINK:
With this selection, the measure source is con-
trolled by the Trigger Link of the Model 2002. Trigger Link
is an enhanced trigger system that uses up to six lines to
direct trigger pulses to and from other instruments.
Summary of Contents for 2002
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