Epson USN 52L, USN 52R manual TCG mode

Echo evaluation with DAC/TCG Operation

TCG mode

AAttention:

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.

Krautkramer USN 52R/USN 52L Issue 05, 02/00 5-33