YUSHI PM-5 Series Operating Manual page 10

3.5 Real Class Analysis of A-SCAN
1. When measuring the thickness, it's possible that that over small
gains prevent the precise results. As showed in the following figure, the
thickness of the testing object is about 5mm, but as for the over small
gain, the measuring result is 10.77mm as the first echo has not broken
the gate and the gate locates the second echo automatically. This is
obviously an incorrect result, and customer can pull up the echo by
enhancing the gain setting to make the first echo brake the gate and
finally pinpoint the correct measurement.
3.12 Real Case 1
2. There are some defects in the testing object, and the gate locks the
defect echoes. As showed in the following figure, the thickness of the
testing object is about 10mm, but as there are obvious defects (the
defect echoes are showed on the display) and the gate locks the defect
echoes which have broken the gate, thus, the testing result shown is the
thickness of the defect area. The right measurement can be realized by
adjusting the gate setting above the defect echoes.
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3.13 Real Case 2
3. If there are some surface faults in the testing object and the gate
locks the defect echoes, the measuring result will be the thickness of
the defect area. In this condition, the customer can use the BLANK
function to get the correct testing result. As showed in the following
figure, the line on the bottom of the screen, which we use to shield the
defect echoes, indicates the blank confines and makes the gate not
catch the echoes within the blank confines, thus, the right thickness
value is acquired.
3.14 Real Case 3
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