Remember that if you have several triggers armed, any of them may be
responsible for the 933A logging data if they become active.
7.4
Event Waveform Capture
7.4.1
Capture Method and Features
The Model 933A samples each of the six measurement channels at 10,240
samples per second at 16 bit resolution, and begins sampling when
triggered from a specified event. Event recording always begins with one-
half second of prefault data, so that you will always capture conditions in
the 25 or 30 cycles of waveform data preceding the fault.
To capture this data the 933A has 128 MB of flash memory that is devoted
entirely to waveform storage, and should be able to store sufficient data
to analyze all channels. Thus, depending on the application, the 933A is
able to capture inrush currents, sags and swells, transients and many other
non-periodic phenomena.
7.4.2
High Speed Waveform Capture
The 933A begins recording data (including high-speed waveform) whenever
a specified event trigger occurs. To assure that you capture the waveform
anomalies you want, make sure to carefully configure the triggering
conditions in the 933A.
Figure 7.11: Reviewing Captured Waveforms
When a specified event happens, the 933A will begin recording data in both
flash modules for the time specified in LOGGING TIME setup screen.
There are two items to configure in this screen: (1) Maximum Logging
Time, and (2) Post Fault Time.
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