Examples Of Using The Trigger Subsystem - Fluke 8588A Operator's Manual

8588A/8558A
Operators Manual

Examples of Using the Trigger Subsystem

General Examples
The default trigger state can be modified with just a few parameters to cause the
measurements to occur on other conditions. For example, from the default
power-on state, in Trigger Setup, set the Trigger event to External. Now readings
will only be taken when (by default) a negative-going TTL edge is detected on the
rear panel TRIG IN BNC. The External Trigger Edge field allows selection of
different polarity and level.
A common setup may be to select a trigger event of Timer. In Trigger Setup set
the Timer period to the desired time between the start of each measurement.
Make sure the measurement takes less time than the specified period.
Alternatively, select Line as the trigger event. Measurements will now be taken
synchronously with the power line. If the measurement takes more than 1 PLC to
complete, the next measurement is started synchronously with the next available
power line cycle.
Another possibility for trigger event is Internal. This will monitor the signal applied
to the terminals and wait for it to pass a threshold in a specific direction. By
default, this is set as a positive-going transition across the zero point of the
range. Every time the applied signal does this, a measurement is started. The
polarity and level of the threshold can be modified, as well as applying a filter and
ac/dc coupling to the monitored signal. This trigger event type is more useful
when combined with other facets of the Trigger subsystem. For example, the
trigger Count can be changed to vary the number of measurements captured for
each cycle of the Trigger subsystem.
Specific Examples
The subsequent examples are provided to give a better understanding of the
Trigger subsystem, and to highlight key aspects. As you try each example, see
the flow diagrams Figures 27 and 28 to understand what the subsystem is doing.
Use the Statistics mode to clearly see when readings are first taken, how many
readings are taken, and when the reading buffer is cleared. Activate Statistics by
pushing .
Each of the examples assume dcv mode, but are in most cases more generally
applicable.
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