Epson USN 52R Operating Manual page 196

Preparing the DGS evaluation
For the reference echo you need a test block with a
known reflector. This reflector can be one of the follow-
ing types:
• backwall
• disk-shaped reflector
• side-drilled hole. With known diameter of the side-
drilled hole, the diameter of a corresponding disk-
shaped reflector can be calculated, provided that the
following requirements are met:
³ 1,5 l
D
SDH
³ 1,5 N
s
with D : diameter of side-drilled hole
SDH
s: sound path in the test object
l:
wavelength in the test material
N: near-field length of the probe used
in the test material
D : diameter of the equivalent
ESR
disk-shaped reflector
Ö
Ö2
D =
p lÖsD
ESR
Krautkramer USN 52R/USN 52L Option DGS
SDH
Issue 02, 03/99
Operation
H Note:
Before measuring, use M to select the setting PEAK
in MEASURE. In addition, activate the gate.
– Connect the required probe to the USN 52 R and
select a suitable reference block for receiving the
reference echo.
– Adjust the A-scan and digital display (please refer to
USN 52R/USN 52L Operating Manual, Chapter 5).
Attention:
Proper A-scan and digital calibration will
assure that the MTL VEL and ZERO parameters are set
correctly, which is necessary for an accurage DGS
curve.
– Switch to the second operation level: X
– Tag the function table DGS: T or V
– Tag the left column of the DGS function group using
J or C.
– Select the required probe number.
Operating the DGS
DGS-21