YUSHI INSTRUMENTS
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reference reflector is, the more precise the calibration is, but the difficulty of calibration increases
correspondingly. When you use a pinhole to do calibration, you can measure the depth and the horizontal
position of the pinhole to calculate the slope coefficient to calibrate the angle, and then you can use the
depth or the horizontal position value that you measure to calibrate the sound velocity and the probe
zero.
4.4 Making of DAC Curve (NB/T 47013-2015 by CSK-IIA block)
1. First calibrate the probe as above mentioned
2. Couple the probe to the reference block to make the echo of the first reference point reach the highest
level (we use CSK-IIA test block as an example, as shown in Figure 4-10).
3. Press the start menu of Gate A to set its position and lock the echo, press to let the echo
display 80% of the screen automatically when it is the highest wave.
4. Press and press again when the first DAC curve is displayed on the screen, the value of
the DAC echo on the submenu is 1 automatically.
5. Move the probe to make the level of the echo of the next reference point be highest, move the gate to
catch the echo, and repeat step 4. At this point, the value of the DAC echo on the submenu is 2
automatically.
6. During the recording, if you find there is something wrong with the newly-recorded reference point,
on the DAC submenu, press to delete this point.
7. The other points can be handled in the same way. The instrument can measure nine point at most. The
general order of the test points is (10mm, 20mm, 30mm, 40mm ...).
Figure 4-10
CSK-IIA Block
