Epson USN 52L - Manual (Page 78)

Krautkramer USN 52R/USN 52L Issue 05, 02/00 5-33
TCG mode
A
Attention:
An echo amplitude evaluation as measurement of the
difference to the reference echo is only possible if the
reference height (height of the first reference echo)
stored during the reference echo recording still applies.
If another echo is stored as reference echo with [dB-
Ref] after recording of the curve, the original reference
echo is lost.
If this is the case, then you need for a flaw evaluation
again the reference block with which the Distance-Am-
plitude Curve was recorded.
After switching-on of the TCG mode, all echoes from
the reference flaws reach the height of the first refer-
ence echo. In addition, you can position the gate over
the entire evaluation range so that each echo is directly
measured.
– Peak the echo from an assumed flaw. If necessary,
increase the gain until the echo exceeds the gate
threshold.
– You can read the sound path in the measurement line
and, in addition with angle-beam probes, the
(reduced) projection distance and the flaw depth.
The enlarged reading in the A-scan (dBR) indicates
the amount in dB by which the flaw echo exceeds or
falls below the reference echo.
The result of an amplitude evaluation is not affected by
a gain variation, i.e. the indicated gain difference dBR is
always the difference between the flaw echo and the
reference echo.
Echo evaluation with DAC/TCG Operation
Krautkramer USN 52R/USN 52L Issue 05, 02/00 5-33
TCG mode
A
Attention:
An echo amplitude evaluation as measurement of the
difference to the reference echo is only possible if the
reference height (height of the first reference echo)
stored during the reference echo recording still applies.
If another echo is stored as reference echo with [dB-
Ref] after recording of the curve, the original reference
echo is lost.
If this is the case, then you need for a flaw evaluation
again the reference block with which the Distance-Am-
plitude Curve was recorded.
After switching-on of the TCG mode, all echoes from
the reference flaws reach the height of the first refer-
ence echo. In addition, you can position the gate over
the entire evaluation range so that each echo is directly
measured.
– Peak the echo from an assumed flaw. If necessary,
increase the gain until the echo exceeds the gate
threshold.
– You can read the sound path in the measurement line
and, in addition with angle-beam probes, the
(reduced) projection distance and the flaw depth.
The enlarged reading in the A-scan (dBR) indicates
the amount in dB by which the flaw echo exceeds or
falls below the reference echo.
The result of an amplitude evaluation is not affected by
a gain variation, i.e. the indicated gain difference dBR is
always the difference between the flaw echo and the
reference echo.
Echo evaluation with DAC/TCG
Operation