Waygate Technologies Krautkramer USM Go, Operating Manual

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Distance-amplitude curve according to JB/T4730 and GB 11345 (CNDAC) 5 Operation
USM Go Rev. 10 (06/2021) 5-109
5.20 Distance-amplitude curve
according to JB/T4730 and
GB 11345 (CNDAC)
CNDAC (China Distance Amplitude Correction) is an
evaluation method for ultrasonic weld testing, based on
the standards JB/T4730 and GB 11345 of the People's
Republic of China.
In CNDAC, reference lines are defined for:
● the rejection (Reject Line RL),
● the amplitude measurement (Sizing Line SL), and
● the evaluation (Evaluation Line EL).
Defined as references are side-drilled holes having cer-
tain diameters.
The option CUSTOM in the function CODE NAME en-
ables you to specify a reference block of your own the
data of which have to be documented separately.
Evaluations according to CNDAC
After recording the reference echo, the CNDAC shows
the reference lines
RL , SL , and EL depending on the
corresponding choice in the functions CODE NAME
(standard) and BLOCK (reference block).
The reference line SL is used for the amplitude mea-
surement. It can be assigned to all gates available
(
READING = SLA , SLB , optionally SLC ).
Examples:
SLA indicates the difference in amplitude of an echo in
the gate A in relation to the reference curve SL at the
position of the echo in dB.
dBrA is identical with SLA .
A%rA indicates the difference in amplitude of an echo
in the gate A in relation to the reference curve SL at the
position of the echo in %. In this connection, the refer-
ence curve at the position of the echo is assumed at
100 %.