10.4 First Peak; Figure 10-5 Mode 3 Detection Example - Olympus 45MG User Manual

Interface echo
Mode indicator
NOTE
Refer to "Echo Window" on page 177 for information on the modes in relation with
the echo window.

10.4 First Peak

With single element transducers, the 45MG normally detects peaks on either the
highest positive or highest negative peak of the RF waveform. This feature works well
for most precision thickness applications.
This normal peak detection can be unstable for applications in which the back-wall
echo is irregular and contains several negative or positive peaks that are close in
amplitude. In such cases, the thickness reading can fluctuate as the gage switches
detection from one peak to another. This can happen, for example, in applications
measuring the length of bolts, or the thickness of the gel coat over fiberglass (see
Figure 10-6 on page 172). In such cases, help stabilize the echo detection and thickness
measurements by selecting the first peak algorithm to detect the first of several peaks
of similar amplitudes (see step 5.c in "Creating a Custom Setup for a Single Element
Transducer" on page 165).
First back-wall echo

Figure 10-5 Mode 3 detection example

Custom Setups for Single Element Transducers
DMTA-10022-01EN, Rev. C, January 2015
Second back-wall
echo
Detection bar
171