another trigger.
Dwell (half cycles)
: Dwell, an integer, refers to the time in half cycles
(at the nominal frequency) for the triggering condition to be true before
which the trigger will become active.
Hysteresis
Hysteresis allows the user to set up some triggering conditions to reduce the
tendency of a wavering signal (e.g. voltage) from generating unnecessary
triggers. Figure 7.8 illustrates a voltage wavering around 130 Vrms, which
is the set Limit for a trigger. To avoid unwanted triggers occurring at
points A, B, C and D, a hysteresis value of 2 was chosen. This prevents a
trigger from occurring unless the voltage drops at least 2 volts below the
Trigger Limit. For the trigger to again become Active (i.e. after point E),
Va would need to again cross the 130-Vrms Limit.
Figure 7.8: Example of Hysteresis
Power Quality Reference
For power quality triggers, install the Power Quality Reference values
by pressing the PWR QUAL REFERENCE soft key seen in Figure 7.9.
Figure 7.10 shows the power quality reference configuration screen. Use
this to set the reference values. In this case, Reference refers to an initial,
nominal voltage/current value, which is preloaded into the register for
Sliding Reference voltages.
Press SETUP
>
7
−
Trigger Setup
>
Pwr Qual Reference soft key as seen
in Figure 7.6. Install the values for any required reference. Press BACK
to return to the Trigger menu.
Remember to press the SAVE SETTINGS
soft key to retain any changes to these settings
.
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