Dakota Ultrasonics
92
mode button on the keypad. The DFX-7 has been programmed to identify the modes
available to a specific transducer.
When configuring the
DFX-7
for specific thru paint applications, all of the scope
parameters will potentially be needed. The delay, range, gain (AGC), thresholds,
gates, and hold-offs will be subject to change. For this reason, they have all been
added to
Hot Menu
fields located directly beneath the A-Scan display for quick and
easy access.
Note:
Once the values of the fields have been changed or modified,
these changes must be saved to a setup location prior to powering the
DFX-7
off.
Failure to do so will result in losing your changes
. Refer to page 157 for
additional information on setups.
THRU-PAINT (INCORRECT) THRU-PAINT (CORRECT)
Refer to the incorrect diagram above. Point
(A)
represents the detection on the first
back wall echo. The true, second back wall, reflection should be detecting at point
(D)
. However, the hold-off
(C)
is setup incorrectly and the
DFX-7
is detecting the ring
down noise of the transducer, on the first reflection, rather than the true second back
wall reflection shown at
(D)
.
Before we look at the diagram with the correct configuration, let’s consider all of our
options on how to fix the problem beforehand. Our
delay
and
Range
will simply
change the view options of the screen – not needed in this example. Will a
gain(AGC)
or
threshold
adjustment fix the problem? Unfortunately, not. Why?
Notice the amplitude of the cycle just to the left of
(B)
. If we tried to increase the
threshold level above the height of the cycle, we would lose our detection for both
echoes resulting in no reading at all. If we decrease our
gain(AGC)
, reducing the
signal amplitudes, we would also lose our detection of both back wall echoes.
Notice that the amplitude of the cycle just to the left of
(C)
. The amplitude of the
cycle, at
(C)
, is less than the amplitude of the cycle at
(B)
, in terms of overall height.
If we decreased our
gain(AGC)
, we would lose the first cycle
(C)
long before losing
the second cycle
(B)
. Therefore, adjusting the
gain(AGC)
or
threshold
levels will
not help us in this example. Our final option is adjusting the
GATE2
hold-off, shown
Содержание DFX-7
Страница 35: ...Dakota Ultrasonics 34 Note Sets where the detection will occur on the negative or positive going echoes...
Страница 219: ...Dakota Ultrasonics 82 10 Finally press the MEAS key to return to the measurement screen and begin taking readings...
Страница 308: ...171 APPENDIX B SETUP LIBRARY Num Name Comment 1 Gn AGC Velocity 1 Enter Custom Name 2 3 4 5 6...
