Checkline DFX-7 - Manual (Page 43)

DFX-7
Ultrasonic Flaw Detector
39
Dual Element Transducer in Echo to Echo mode
Echo-Echo Verify Mode – Thru-Verify (E-EV)
The echo-echo verify mode measures between 3 reflections. Similar to E-E mode,
this technique is commonly used to eliminate errors from surface coatings and also to
make measurements in multiple layered materials. The primary benefit of this mode,
is that a comparison is made, between the 2
nd and 3 rd echoes, to verify that a peak
jump has not occurred, providing an additional level of confidence to the
measurement. The disadvantage is that 3 reflections are needed which requires the
use of gates with controllable thresholds to adjust for sensitivity over a given
measurement range.
Dual Element Transducer in Echo to Echo mode
Pulse Echo Coating Mode – Coating On (PECT)
A custom hybrid combination mode using properties from the basic modes along with
a group of special techniques and theoretical wave phenomena’s to measure coating
and material thicknesses at the same time, while still retaining the ability to locate
flaws and pits in materials. Therefore, the best description for this hybrid mode is
Pulse-Echo Coating mode.
Coating Mode – Coating Only (CT)
Once again, this is a custom hybrid combination mode using special techniques to
effectively measure the thickness of coatings that are either adhered to metallic
surfaces or in stand alone form. In this mode a two point calibration must be
performed. If the user will be measuring coating that has been applied to a metal
surface, the calibration must be performed using coating samples coupled to a metal
surface when calibrating. To explain further, a drop of couplant must be applied in
between the coating samples and metal surface. If the coating has not been applied
to a metal surface, the calibration should be performed accordingly.