Calibrating the EPOCH 4PLUS
Part # 910-250C
67
Figure 32
Verifying the Refracted Angle
2. Move the probe backward and forward to “peak up” the echo coming from the large
circular hole in the side of the block. The circular hole may be filled with Plexiglas, but
the procedure is the same.
Tip:
The Peak Memory feature on the EPOCH 4PLUS is an excellent tool to aid
in finding the peak of the signal.
3. Hold the probe stationary once you have peaked up the signal. Note the degree mark
on the block that lines up with the BIP, which you marked on the side of the wedge in
the previous step. This is the actual refracted angle (Beta) for this particular transducer
and wedge in steel.
If this value for Beta differs from the value entered previously, enter the corrected
angle now via the [ANGLE] key and the [ ], [ ], [
], and [
] keys.
7.5.3
Calibrating for Distance
Note:
This step differs depending on which type of IIW calibration block is used.
The ASTM E-164 IIW Type I Block, which has a crescent cut in the side,
produces echoes at 4" (100 mm) and 9" (225 mm) on the screen. The U.S. Air
Force IIW Type II Block, which has a large cutout in the side, produces
echoes at 2" and 4" on the screen. The procedure below uses the Olympus
NDT IIW Type I carbon steel calibration block, part number TB7541-1.
We recommend that the EPOCH 4PLUS’s Range parameter be set to 10"
(250 mm) for this step. Regardless of whether a Type I or Type II Calibration
block is used, this should ensure that the echoes from the block are visible on
screen.
To calibrate for distance, follow these steps:
1. Couple the probe to the block so that the BIP is directly over the “0” mark on the
ASTM test block (or the Air Force block). Do not move the transducer from this
point during this step.
Summary of Contents for Panametrics Epoch 4 Plus
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