M5-CYG4P-M-01_Iss5.doc
Cygnus 4+ Operating Manual
33
6.
Using the A-Scan Display
To help ensure reliable measurements in Single Echo and Echo-
Echo measurements the gauge has an A-Scan display that can be
used to visually verify the thickness measurements are sensible
and therefore reliable. With some practice any user can quickly
and easily use the A-Scan to decide if the measurement is correct.
To view the A-Scan display use the Left and Right navigation keys
to switch between the measurement screen views (see
Measurement Screen Views on page 25).
The A-Scan display shows the actual ultrasound echo pulses as
received by the gauge; these echo pulses are used by the gauge
to determine the thickness measurement if possible.
The gauge works by generating a short pulse of ultrasound that is
coupled into the object you are measuring. This pulse then travels
through the object and is reflected back to the probe as an echo
by either the back-wall of the object and/or any internal flaws or
corrosion pits. When the echo pulse hits the probe surface a signal
is received by the gauge, this signal is shown on the A-scan
display as an echo peak, the taller the peak the stringer the signal.
Single Echo Mode
The A-Scan display is very useful when measuring in Single Echo
modes, as there is no verification of the thickness measurement
observing the A-Scan display will help the user verify the echo
detected is the correct one – the back-wall echo.
This A-Scan shows a good clear
ultrasound signal.
There is a well-defined back-wall echo
and the arrow is correctly placed.
The measurement value of 12.7 is stable
when green in colour.
Good Signal