Keithley 2657A, Справочное руководство, Страница: 165 / 805

Model 2657A High Power System SourceMeter® Instrument Reference Manual Section 3: Functions and features
2657A-901-01 Rev. B/December 2012 3-51
The programming example below illustrates how to configure the LAN trigger mode.
-- Set LAN trigger 2 to have falling-edge mode.
lan.trigger[2].mode = lan.TRIG_FALLING
Understanding LXI trigger event designations
LAN trigger objects generate LXI trigger events, which are LAN0 to LAN7 (zero based). In the
command table, the LXI trigger events can be accessed using
lan.trigger[1]
through
lan.trigger[8]
.
lan.trigger[1]
corresponds to LXI trigger event LAN0 and
lan.trigger[8]
corresponds to LXI
trigger event LAN7.
Generating LXI trigger packets
You can configure the Model 2657A to output an LXI trigger packet to other LXI instruments.
To generate LXI trigger packets:
1. Call the
lan.trigger[
N
].connect()
function.
2. Select the event that triggers the outgoing LXI trigger packet by assigning the specific event ID to
the LAN stimulus input.
Make sure to use the same LXI domain on both the Model 2657A instrument and the other
instrument. If the Model 2657A has a different LXI domain than the instrument at the other end of the
trigger connection, the LXI trigger packets will be ignored by both instruments.
Command interface triggering
A command interface trigger occurs when:
•
A GPIB GET command is detected (GPIB only)
•
A VXI-11
device_trigger
method is invoked (VXI-11 only)
•
A
*TRG
message is received
Use
trigger.EVENT_ID
to monitor for command interface triggers. To ensure that commands and
triggers issued over the command interface are processed in the correct order, a trigger event is not
generated until:
•
The trigger command is executed
•
trigger.wait()
retrieves the trigger command from the command queue before it would
normally be executed
Command interface triggering does not generate action overruns. The triggers are processed in the
order that they are received in the Model 2657A command queue. The Model 2657A only processes
incoming commands when no commands are running. Unprocessed input triggers can cause an
overflow in the command queue. It is important to make sure a script processes triggers while it is
running.