6482-901-01 Rev. A / August 2012
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8-5
Model 6482 Dual-Channel Picoammeter / Voltage Source Reference Manual
Section 8: Triggering
Trigger delay
A programmable trigger delay is available before the source action. The trigger delay can be set
manually from 0.00000 to 999.99990 seconds. Note that this delay is separate from the delay
action of the source, delay, and measure (SDM) cycle. The delay action is discussed next.
Source, delay, and measure actions
The source, delay, and measure (SDM) cycle of the Model 6482 consists of three actions: Source,
delay, and measure:
SOURCE action
: Any programmed output voltage level changes are performed.
DELAY action
: This programmable delay is used to allow the source to settle before a
measurement is performed. It can be set manually from 0.00000 to 9999.99800 seconds, or
autodelay can be enabled. With autodelay enabled, the Model 6482 automatically selects a
nominal delay period based on the selected current measurement range.
NOTE
The delay action is set from the CONFIGURE SRC1 or CONFIGURE SRC2 menu. See
,
MEASURE action
: During this phase of the SDM cycle, the measurement process takes place. If
the repeat filter is enabled (see the MEASURE action inset of
), the instrument samples
the specified number of reading conversions to yield a single filtered reading (measurement). If
using the moving filter or if the filter is disabled, only a single reading conversion will yield a
reading.
Counters
Programmable counters are used to repeat operations within the trigger model layers. For
example, if you are performing a 10-point sweep, set the trigger counter to 10. Operation will stay
in the trigger layer until the 10 source-delay-measure points of the sweep are performed.
If you want to repeat the sweep three times, set the arm counter to three (3). Three 10-point
sweeps can then be performed which equals 30 source-delay-measure actions.
The maximum buffer size for the Model 6482 is 3000 readings. The product of the two counter
values cannot exceed 3000. For example, if you set an arm count of two (2), the maximum trigger
count will be 1500 (3000 / 2 = 1500). However, you can set the arm count to INFINITE. With an
infinite arm count, the maximum trigger count is 3000.
NOTE
When a sweep is configured, the trigger model settings will not change until the sweep is
started. After the sweep is finished, the trigger model will reset to the previous settings.
Output triggers
The Model 6482 can be programmed to output a trigger (using the rear panel trigger link
connector) after various trigger model operations. An output trigger is used to trigger another
instrument to perform an operation. See
“Trigger link,” page Section 8-6
, for more information.
Trigger Layer Output Triggers
: After each action (source, delay, and measure), the Model 6482
can be programmed to send out an output trigger if TRIGGER-LINK is the selected trigger-in
source. For example, if the trigger out event for measure is ON, an output trigger will be sent after
the measure action. When used with a scanner, an output trigger after each measurement can
signal the scanner to select the next channel in the scan.
Arm Layer Output Trigger
: The Model 6482 can also be programmed to output a trigger when
operation leaves the trigger layer and enters into the arm layer. This output trigger is typically sent
to another instrument to signal the end of a scan or sweep.
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