Front Panel Operation
2-73
2.15.1 Trigger model
The following information describes triggering of the Model
6517A from the front panel. The flowchart of Figure 2-56,
which is the simplified trigger model, summarizes basic
front panel triggering. The flowchart of Figure 2-57, which
is the complete trigger model, summarizes advanced front
panel triggering.
BASIC TRIGGER MODEL
As shown in Figure 2-56, the basic trigger model provides
the fundamental trigger options needed for many instrument
operations.
Basic triggering is selected and configured from the BASIC
menu item of the CONFIGURE TRIGGER menu. Refer to
Figure 2-56 for the following explanation of the basic trigger
model.
Idle
While in the idle state, the instrument cannot perform mea-
surements. The front panel ARM indicator is off when the in-
strument is in idle. Pressing TRIG takes the instrument out
of idle (ARM indicator turns on).
Trigger Mode
With the continuous trigger mode selected, operation contin-
uously loops around the control source to make measure-
Idle
Continuous
Event
Detection
Device
Action
One
Shot
MODE
MODE
Control
Source
Output Trigger
Immediate
Manual
GPIB
External
Timer
Figure 2-56
Basic trigger model
ments (device action). This trigger mode provides
continuous reading conversions.
With the one-shot trigger mode selected, operation waits for
the selected control source event to occur before making a
measurement (device action). A measurement occurs every
time the source event is detected (see Control Sources).
The trigger mode is selected from the BASIC (MODE) op-
tion of the CONFIGURE TRIGGER menu.
Control Sources
With the one-shot trigger mode selected, a measurement (de-
vice action) does not occur until the selected control source
event is detected. The control sources are explained as fol-
lows:
• Immediate — With this control source selected, event
detection is immediately satisfied allowing operation to
continue. Using this selection is effectively the same as
using the continuous trigger mode.
• Manual — Event detection is satisfied by pressing the
TRIG key. Note that the Model 6517A must be taken
out of remote before it will respond to the TRIG key.
Pressing LOCAL takes the instrument out of remote.
• GPIB — Event detection is satisfied when a bus trigger
(GET or *TRG) is received by the Model 6517A.
• External — Event detection is satisfied when an input
trigger via the EXTERNAL TRIGGER connector is re-
ceived by the Model 6517A.
• Timer — Event detection is immediately satisfied on
the initial pass through the layer. Each subsequent de-
tection is satisfied when the programmed timer interval
(1 to 999999.999 seconds) elapses.
Output Triggers
After every measurement (device action) a trigger pulse is
applied to the METER COMPLETE connector on the rear
panel of the instrument. This out-going trigger pulse can be
used to trigger another instrument to perform an operation
(see paragraph 2.15.4 External Triggering).
ADVANCED TRIGGER MODEL
As shown in Figure 2-57, the advanced trigger model pro-
vides more triggering options, which are programmed from
the ADVANCED menu item of the CONFIGURE TRIG-
GER menu. Note that scanning operations use this trigger
model.
Advanced triggering is selected and configured from the
ADVANCED menu item of the CONFIGURE TRIGGER
menu. Refer to Figure 2-57 for the following explanation of
the advanced trigger model.
