User's Manual

1760
Reference Manual
5-18
These triggers can be applied to phase and Neutral voltages (V), and phase and Neutral
currents (I). Max and Wave triggers can also be applied to phase to phase voltages (Vp-
p).
The graphic on the top of the panel illustrates the meaning of the triggers.
Select the recordings you want to trigger with the RMS and Oscilloscope check-boxes.
Five types of different oscilloscope triggers are available: Level, Sine, Max, Phase, and
Wave.
Level is comparable to the trigger level on an oscilloscope. Positive (rising) or negative
(falling) slope is determined by the symbol left to the numerical input field.
The Level Trigger is used for the
precise investigation of short term voltage and current
peak values. It is important to define appropriate pre-trigger time periods in Recording
Modes. This allows the history before the event and the whole event to be analyzed in
detail.
The Sine trigger is sensitive to deviations from the ideal sine wave. Based on zero
crossings and amplitudes of the last cycle an ideal sine wave is calculated. If the
deviation of the samples of the actual mains cycle from this ideal sine wave is higher than
the limit value a recording is started.
The Sine trigger can be used for detection of commutation notches, fast voltage sags or
sudden waveform distortions.
The Max trigger monitors the maximum values independently of the polarity. It detects
positive or negative peaks. It is used for precise investigation of short term voltage and
current peak values.
The Phase trigger responds to phase jumps between consecutive cycles. The zero
crossings of adjacent periods are evaluated.
The Phase trigger can be used for the detection of over currents or short circuits in
neighboring or host networks.
The Wave trigger monitors the differences in the waveforms of consecutive mains
cycles. The samples of the last cycle are compared with the samples of the actual cycle.
This trigger is a general purpose trigger which detects virtually all non-stationary
phenomena of a certain magnitude.
The Wave trigger is perfectly suitable for all kinds of disturbance analysis and
troubleshooting, because most of the power quality problems result in a sudden change of
the waveform. From the recorded waveforms, we can find the cause of distortion in most
cases: switching of capacitor banks, commutation distortions, oscillations in the network,
or ground short in the medium voltage system show typical significant waveforms.