4
1, Coupling Status:
Indicate the coupling status. While the gauge is taking a measurement, the
coupling status should be on. If it is not on or not stable, the gauge is having difficulty achieving a stable
measurement, and the thickness value displayed will most likely be erroneous.
2, Unit:
Current unit system. MM or IN for thickness value. M/S or IN/
μ
S for sound velocity.
3, Battery Information
: Display the rest capacity of the battery.
4, Information Display:
Displays the measured thickness value, the sound velocity and shows hints of
current operation.
2.2 Keypad Definitions
Turn the instrument on/off
Sound velocity calibration
Turn on/off the EL backlight
Enter
Probe-Zero operation
Plus;
Turn on/off Scan mode
Unit switch between Metric
and Imperial system
Minus;
Switch between pulse-echo and
echo-echo mode
Data Save or Data Delete
3 Preparation
3.1 Transducer Selection
The gauge is inherently capable of performing measurements on a wide range of materials, from various
metals to glass and plastics. Different types of material, however, will require the use of different
transducers. Choosing the correct transducer for a job is critical to being able to easily perform accurate
and reliable measurement. The following paragraphs highlight the important properties of transducers,
which should be considered when selecting a transducer for a specific job.
Generally speaking, the best transducer for a job is one that sends sufficient ultrasonic energy into the
material being measured such that a strong, stable echo is received by the gauge. Several factors affect
the strength of ultrasound as it travels. These are outlined below:
Initial Signal Strength. The stronger a signal is to begin with, the stronger its return echo will be. Initial
signal strength is largely a factor of the size of the ultrasound emitter in the transducer. A large emitting
area will send more energy into the material being measured than a small emitting area. Thus, a
so-called “1/2 inch” transducer will emit a stronger signal than a “1/4 inch” transducer.
Absorption and Scattering. As ultrasound travels through any material, it is partly absorbed. If the
material through which the sound travels has any grain structure, the sound waves will experience
scattering. Both of these effects reduce the strength of the waves, and thus, the gauge’s ability to detect
the returning echo. Higher frequency ultrasound is absorbed and scattered more than ultrasound of a
