Automatic Calibration - Epson USN 52R Operating Manual

Operation
Higher sound velocity
Due to the V-path error, a higher sound velocity than
the test material is required when calibrating, especially
with smaller thicknesses. This is typical of dual (T/R)
probes and acts as compensation of the V-path error.
Owing to the described effect there is a drop in the
echo amplitude with smaller thicknesses which should
be carefully observed with values < 2 mm.
A calibration block having different thicknesses must be
used for calibration. The thicknesses are to be selected
so that they include the expected measurement value.
– Set PULSER in the function group PULS to DUAL.
– Set RANGE according to the test task and the probe
being used..
– Set TOF to FLANK.
– Couple the probe to the thinner part of the calibration
block and peak the echo.
– Set the flank as steeply as possible by adjusting the gain.
– Set Gate a on the first echo.
– Set ZERO in the function group S-CAL so that the
measurement line display the correct value at
"S=...".
5-22
– Couple the probe to the thicker part of the calibration
block and peak the echo.
– Set the flank as steeply as possible by adjusting the
gain.
– Set Gate a on the first echo.
– Set the sound velocity "C" so that the correct value is
displayed in the measurement line at "S=...".

Automatic calibration

The instrument has an automatic calibration capability
via the function AUTO CAL. Two calibration echoes
must be entered. The instrument then carries out a plau-
sibility check and automatically sets the parameter.
– Set the function AUTO CAL in the second operation
level (right function table) to ON.
– Return to the first operation level with X and select
function group S-CAL with I.
The function group S-CAL changes in preparation for
the automatic calibration and now contains the CAL
function (calibration) as well as the function S-REF
(sound path for the reference echo).
Issue 05, 02/00
USN 52R/USN 52L calibration
Krautkramer USN 52R/USN 52L