GE Krautkramer USM 35X, Operator'S Manual

Page: 119 / 226

Krautkramer USM 35X Issue 01, 04/2005 5-71
Operation
Echo evaluation with DAC
In order to be able to evaluate a flaw indication by
means of the DAC, certain conditions must be met:
• The distance-amplitude curve must already be
recorded.
• It only applies to the same probe that was used
when recording the curve. Not even another probe of
the same type must be used!
• The DAC only apply to the material corresponding to
the material of the reference block.
• All functions affecting the echo amplitude must be
set the same way as they were when the curve was
recorded. This applies in particular to the following
functions:
POWER , FREQU , RECTIFY , MTLVEL and
REJECT .
DAC according to JIS Z3060-2002 (only USM 35X DAC and USM 35S)
5.20 Evaluation according to the
DGS method (only USM 35X S)
With the USM 35X S, you can use both the DAC and
the DGS method of amplitude evaluation.
Measuring with DGS
Using the DGS function (Distance Gain Size), you can
compare the reflecting power of a natural flaw in the
test object with that of a theoretical flaw (circular disk-
shaped equivalent reflector) at the same depth.
A
Attention:
You are comparing the reflecting power of a natural flaw
with that of a theoretical flaw. No definite conclusions
may be drawn on the natural flaw (roughness, inclined
position, etc.).
The so-called DGS diagram forms the basis for this
comparison of the reflecting power. This diagram con-
sists of a set of curves showing the correlation of three
influencing variables:
Krautkramer USM 35X Issue 01, 04/2005 5-71
Operation
Echo evaluation with DAC
In order to be able to evaluate a flaw indication by
means of the DAC, certain conditions must be met:
• The distance-amplitude curve must already be
recorded.
• It only applies to the same probe that was used
when recording the curve. Not even another probe of
the same type must be used!
• The DAC only apply to the material corresponding to
the material of the reference block.
• All functions affecting the echo amplitude must be
set the same way as they were when the curve was
recorded. This applies in particular to the following
functions:
POWER , FREQU , RECTIFY , MTLVEL and
REJECT .
DAC according to JIS Z3060-2002 (only USM 35X DAC and USM 35S)
5.20 Evaluation according to the
DGS method (only USM 35X S)
With the USM 35X S, you can use both the DAC and
the DGS method of amplitude evaluation.
Measuring with DGS
Using the DGS function (Distance Gain Size), you can
compare the reflecting power of a natural flaw in the
test object with that of a theoretical flaw (circular disk-
shaped equivalent reflector) at the same depth.
A
Attention:
You are comparing the reflecting power of a natural flaw
with that of a theoretical flaw. No definite conclusions
may be drawn on the natural flaw (roughness, inclined
position, etc.).
The so-called DGS diagram forms the basis for this
comparison of the reflecting power. This diagram con-
sists of a set of curves showing the correlation of three
influencing variables: