Section 3
Functions and features
In this section:
Scanning and triggering ............................................. 3-1
Trigger model ............................................................. 3-1
Scan and step counts................................................. 3-4
Basic scan procedure................................................. 3-5
Remote interface scanning......................................... 3-8
Hardware trigger modes........................................... 3-12
Understanding synchronous triggering modes ......... 3-17
Events ...................................................................... 3-21
Scanning and triggering
A scan is a series of steps that opens and closes switches sequentially for a selected group of
channels. During each step, actions occur, such as waiting for a trigger, taking a measurement, and
completing a step count. Scans automate actions that you want to perform consistently and
repeatedly on a set of channels.
Triggers are events that prompt the instrument to move from one step to another in a scan. Triggers
can come from a variety of sources, such as a key press, digital input, or expiration of a timer. The
sequence of actions and events that occur during the scan is called the trigger model.
Scanning and triggering allow you to synchronize actions across channels. You can set up a scan
using the trigger model to precisely time and synchronize the Model 707B or 708B between channels
and multiple instruments. You can also use triggers without the triggering model to set up a scan to
meet the needs of a specific application that does not fit the triggering model.
Trigger model
When you run a scan, the scan sequence follows a trigger model. The trigger model is shown in the
following flowchart.
NOTE
In Models 707B and 708B, only scanning operations use the trigger model. Individual open and close
commands do not affect the trigger model.
The trigger model is used during a scan only. For front panel operation, you use the
SCAN
and
STEP
keys to perform scan actions. For remote operation, you use the scan functions and attributes
commands, for example,
scan.execute()
and
scan.mode
.
