Dakota Ultrasonics MVX - Manual (Page 75)

MVX High Performance Thickness Gauge
8.2 Setting Up Thru Paint Mode
The first thing to note in this section, is that by selecting the transducer type from the
list of probes stored in the MVX, a basic echo -echo thru paint configuration is recalled
from memory. Each of the transducers in the list contain pre-configured echo -echo
settings. However, fine adjustments may be necessary in order to be suitable for
your specific applications. These configurations are general setups only. Once the
transducer type has been selected and the appropriate calibration procedure
completed, the MVX can toggle between pulse-echo (flaws & pits), and echo-echo
(thru paint) modes by simply pressing the MULTI MODE key located on the keypad.
Refer to page 31 for additional information.
When configuring the MVX for specific thru paint applications, all of the scope
parameters will potentially be needed. The delay, width, gain, threshold, gate1, and
gate2 features 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 MVX off. Failure to
do so will result in losing your changes.
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 MVX 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 width will simply
change the view options of the screen – not needed in this example. Will a gain or
threshold adjustment fix the problem? Unfortunately, not. Why? Notice the