Olympus EPOCH 6LT, User Interface Manual

Page: 197 / 232

DMTA-10084-01EN, Rev. 2, November 2018
Software Features and Options 187
• The first is an inspection where potential defects may not be oriented parallel to
the direction of sound from the transducer. Sound will still reflect from these
defects, but the reflection may be directed away from the transducer. In this
situation, little or no signal is returned to the instrument for direct measurement.
Generally, these defects are instead detected by monitoring for back wall signal
loss or attenuation. This back wall amplitude change can be missed entirely if the
back wall signal is saturated. The BEA allows you to monitor the back wall for
any signal loss at a lower gain setting, while still scanning the remainder of the
test piece at a high gain level for small defects.
• The second is an inspection for porosity. Porosity tends to scatter sound instead of
returning a clear echo. In this situation, back wall amplitude may be the only way
to positively differentiate porosity from material grain structure. The BEA is used
to display the entire back wall signal on the screen so that it can be closely
monitored.
Both inspection forms are useful when detecting very small defects.
11.6.1 Enabling the BEA Option
The BEA is enabled in the Gate2 dialog box.
To enable the BEA
1. On the setup menu, turn the adjustment knob to select the Gate2 icon ( ). See
“Setup Mode” on page 17 for details on opening the setup menu.
2. Press the Enter key to open the gate 2 dialog box.
3. Press the Enter key and turn the adjustment knob to set the G2 Status to BEA (see
Figure 11-28 on page 188).
When the BEA is activated, gate 2 is on and displayed in its previous position.