ACS A1270 EMAT, Руководство по эксплуатации

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1.3.2 Operation principle
The operation principle of the instrument is based on the measurement of time required for the double traverse of ultra-
sonic waves through the inspected object from one surface to another, which is further recalculated into the thickness value.
The EMAT is used to emit the ultrasonic pulses into the object being inspected and receive the reflected pulses. The EMAT
shall be installed on the surface of the inspected object in the place where the thickness shall be measured. The EMAT has a
pointed directional characteristic of irradiation direction and ultrasonic reception, so the thickness can be measured just below
the installation place of the transducer. Provided there are cavities in the surface opposite to the surface with the installed
EMAT, the ultrasonic pulses will be reflected from them and the thickness will be determined as the shortest distance from the
external surface to the cavities.
А1270 Electro-Magnetic Ultrasonic Thickness Gauge
Operation Manual
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ACOUSTIC
CONTROL
SYSTEMS
1.3.3 Operation modes
The operation modes of the thickness gauge are as follows:
- MEMORY is the measurement mode with the indication of the recorded results;
- B SCAN is the measurement mode with the graphical indication of the profile testing object;
- А SCAN is the measurement mode with the graphical signal indication;
- SETUP is the mode for settings and selection of the measurement parameters.
The instrument allows for recording of the results in its memory when operated in any of the measurement modes.
In the MEMORY mode the thickness gauge allows for the prompt detection of thickness of the inspected object; it allows
the operator to view the recorded measurement results on the display, edit the recordings by means of additional measure-
ments and record the obtained data in the correctable memory cells.
The A-SCAN mode allows the elimination of false readings caused by the presence of discontinuities in the material of the
inspected object. In this mode the signals are displayed in the form of an A-SCAN, and measurement conditions and criteria
are determined directly during the operation. Four measurement ways are possible: by the first signal exceeding the strobe
threshold, by the maximum signal in the strobe, between two maximum signals in the strobe and ACF by the strobe. It is also
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