Specifications

13. Calibrating for Digital Measurement
Page 86 USN52 L Operating Manual
False readings are often caused by excessive ringing of the first
echo or nonrelevant signals between the first and second backwall
echoes. The b-START feature prevents false readings by block-
ing the measurement during the b-START interval immediately after
the first measurement echo.
11. Set b-START as close as possible to the trailing edge of
the first measurement echo:
WARNING!
To avoid false readings, do not allow the first echo signal, or
any nonrelevant indications, to encroach on gate b. Measure-
ment will be determined by the first intersection between any
signal (leading or trailing edge) and gate bar.
12. Select the S-CAL menu:
13. Observe the S= value in the measurement line and obtain a
stable reading.
If desired use the enlarged display:
or
14. Adjust MTL VEL until the displayed S= value matches the
known thickness of the test block:
Following is a typical A-scan and measurement line display for
MULTECHO measurement with a single element contact probe.