Checkline DFX-7 - Manual (Page 64)

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CHAPTER SEVEN
USING THE DISPLAY OPTIONS
A key feature of the DFX-7 is the ability to toggle between four different display
options; Digits, RF, RECT and B-Scan. All views provide a digital readout of base
material and coating thickness measurements, while also displaying the alarm
tolerances, if active. A key feature of the DFX-7 is the waveform display. The
waveform is a graphical representation of the sound reflections returning to the
transducer. Consider standing at the base of a canyon and screaming “Hello There”.
After a brief delay, you will here multiple echoes, “Hello There’s” repeated back to
you. The waveform display shows the amplitude of the signal received on the vertical
(Y) axis and time (shown in units of thickness) on the horizontal (X) axis. The
waveform display is very useful for viewing and adjusting the location of the gates.
The gates are typically used to eliminate potential surface noise by adjusting the
starting point in single echo modes, for multi echo measurement modes, as well as to
adjust the threshold (sensitivity) in either mode. The waveform display is also very
useful for locating pits and internal flaws in materials.
The B-Scan display is also very useful when scanning surfaces and viewing the cross
section of the test material. It provides a convenient way of visually profiling, or
drawing a picture of, the blind surfaces during a scan. The B-Scan display is also
equipped with a scan bar representing the overall thickness. The scan bar gives the
user a visual indication when a flaw or defect passed over during the scan process.
The scan bar will deflect off of the defect and return back to the overall thickness.
Visually, this is much easier to notice than watching for changes in the digital value
displayed. The scan bar has also been included in the large digits display mode for
the same purpose.
Note: The following chapter outlines some of the fine adjustment features of the
DFX-7
. The DFX-7 has four different display options (RF A-Scan, Rectified A-Scan,
B-Scan, and Large Digits). We’ll take a better look at these options in this chapter.
Note: In order to recall and use the new adjustments made to the DFX-7 at a later
time, the user must save the modified settings in one of the setup locations prior to
powering off the unit. Refer page 157 for more information on setups.