TOPAZ
– Technical Guidelines
6
2.
Auto-Crossing Gates
Gates are used to extract information from an A-scan signal in order to create C-scan data, turn ON or
OFF an alarm signal, obtain information (signal amplitude, location...) or set a signal synchronization.
The trigger parameter allows you to define if the detection gate data will take into account the crossing
threshold location (
Crossing
) or the maximum peak location (
Maximum
) within the gate.
Two new triggering modes have now been added:
Crossing (-6dB)
and
Crossing (-12dB)
.
In these two modes, the detection threshold changes according to the maximum amplitude of the signal
within the gate. Threshold is automatically adjusted at -6dB or -12dB from the live maximum signal
amplitude.
This feature is useful to compensate signal response variations due to uneven surfaces caused by
corrosion or pitting.
To implement auto-crossing gates:
1.
In the
UT Settings
menu, go in the
Gates
tab.
Figure 2-1 UT Settings menu - Gates Tab
2.
Click
Trigger
.
3.
Select
Crossing (-6dB)
.
To adjust the automatic threshold setting to -6dB from the maximum signal amplitude.
OR
Select
Crossing (-12dB)
.
To adjust the automatic threshold setting to -12dB from the maximum signal amplitude.
Your detection is now set in auto-crossing mode.
