Olympus EPOCH 650, Руководство пользователя

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DMTA-10055-01EN, Rev. A, February 2015
Calibration 161
Figure 9-13 Entering the Velocity Cal thickness value
9.7 Calibrating in Echo-to-Echo Mode
The sample echo-to-echo calibration described below is performed using Olympus
delay line transducer part number V202-RM, with a frequency of 10.0 MHz and an
element diameter of 6 mm (0.25 in.).
In Echo-to-echo mode, the calibration requires a test block with only one known
thickness, made from the material to be measured. Ideally, the thickness measurement
is very close to the expected thickness of the material to be inspected. Echo-to-echo
mode measures the distance between two actual indications, one representing the
measurement start point and one representing the measurement end point. This
eliminates the need for zero offset calibration, since the effects that cause a zero offset
are accounted for by gating the start-point indication. Therefore, in an Echo-to-echo
mode calibration, the instrument must only calibrate for material velocity to provide
accurate readings.
For this example, we are using Olympus standard 5-step steel-test block, part number
2214E. The steps measure 0.100 in., 0.200 in., 0.300 in., 0.400 in., and 0.500 in.