Measurement Computing LogBook Series - Manual (Page 169)

Software Reference 989592 LogView LV-43
If Absolute Time is selected for the trigger source, the
window changes as shown in the figure at right. The
parameters include the date and time as well as options
for re-triggering after a specified duration.
A wide variety of trigger sources and stop events provide
great flexibility in exception-capturing. If data collection
is desired only under specific conditions, appropriate
trigger conditions can be so specified. Besides the
trigger event, you can define a pre-trigger and post-
trigger for the trigger block. An example of exception-
capturing would be to collect 100 pre-trigger scans and
1000 post-trigger scans every time a designated channel
read a specified temperature.
Using Absolute Time as a Trigger Source
To conserve memory when collecting high-speed data, use the trigger to take snapshots of
information only during the appropriate periods.
When using a trigger to start the acquisition, a pre-trigger count can be supplied so that information just
before the trigger can be collected and saved (LogBook’s buffer allows pre-trigger data to be stored
temporarily until saved in a trigger block). The post-trigger definition specifies when the data collection
activity should end.
Pre-Trigger Setup Post-Trigger Setup
You can also use a calculated channel as a trigger source, but you must use an analog output or digital
channel as an intermediary. The calculated channel can be based on real channels and user logic to create
an analog output channel or a digital output channel that could then be the input for the trigger event or
stop event. A calculated channel can describe virtually any combination of channel conditions. For
example, you can develop a calculated channel called TRIG and specify it as the trigger channel. If the
channel’s equation is TRIG = (Temp1-Temp2)>50.0°, the data collection process will be triggered when
the difference between the 2 channels is greater than 50.0°.
Scan Rate Setup
Scan Rate Setup. Accomplished on the right-half of the Acquisition Configuration Window.