Trigger Model Components - Keithley 708B Reference Manual

Models 707B and 708B Switching Matrix Reference Manual

Trigger model components

The individual components of the trigger model are explained in the following paragraphs.
Start scan
When a scan is initiated, the instrument leaves the idle state and prepares to start scanning. To
prepare for scanning, it verifies that channel settings match the scan settings (such as opening all
channels or opening only channels on specific slot). After preparation is complete, the instrument
generates the Scan Ready Event and either starts immediately or waits for the arm stimulus event.
When the scan is complete, the instrument returns to the idle state.
Wait for scan start trigger
The scan can start immediately after receiving the Scan Ready Event, or the instrument can wait for a
start trigger (also called the arm action). If it waits for a start trigger, the scan does not start until it
receives the start trigger.
When the scan starts, the instrument generates the Scan Start Event.
Wait for channel action trigger
The channel action trigger is an event that tells the instrument to begin processing the next channel
action.
You can bypass the channel action trigger if this is the first step of the first scan count. Bypass is
available from the font-panel CONFIG+SCAN menu, or by using the command scan.bypass.
Channel action
During the channel action, the instrument opens or closes channels as needed.
When the channel actions are complete, the instrument generates the Channel Ready Event.
Step count complete
The trigger model repeats these actions for every step in the scan list. The instrument loops back to
wait for channel action trigger for each step until the steps are complete.
When all the steps are complete, the instrument generates the Scan Complete Event.
Scan count complete
The scan can be set to repeat. If the scan count is not complete, the instrument loops back to wait for
the scan start trigger.
Idle
After the instrument has completed the scan list the requested number of times, the instrument
generates the Idle Event. This is the completion of the scan.
707B-901-01 Rev. A / August 2010
Section 3: Functions and features
3-3