15
8.1 BEFORE YOU START
•
Prepare the surface.
•
Ensure the correct transducer is selected and set in the gauge.
•
Select the correct measurement mode - see “Measurement - Modes” on page 10.
•
Set the zero point of the transducer,if necesssary - see:
•
“Transducer - Zeroing” on page 12 and
•
Calibrate the gauge - see:
•
“Calibrating - for a Material” on page 13 and
•
Choose the measurement view (DIGITS, RF or RECT, or B-SCAN) - see “The Measurement
Screen” on page 7.
8.2 PROCEDURE
1.
Apply couplant
For the gauge to work correctly there must be no air gap between the transducer and the
surface of the material to be measured. This is achieved using a couplant.
Before the transducer is placed on the surface, put a small amount of couplant supplied with
the gauge on the surface of the material. Typically a single drop is sufficient.
2.
Place transducer onto the surface of the material to be measured
Press the transducer wearface into the couplant. Only moderate pressure is necessary to
keep the transducer stationary and the wearface seated flat against the surface of the
material.
3.
Read display
If six or seven bars of the stability indicator are showing, the display will be reading the correct
thickness of the material directly beneath the transducer.
If the stability indicator has fewer than five bars showing, or the numbers on the display seem
erratic, check to make sure that there is an adequate film of couplant beneath the transducer,
and that the transducer is seated flat against the material. If the condition persists, it may be
necessary to:
•
adjust the gain, or
•
select a different transducer (size or frequency) for the material being measured.
The gauge will perform a number of measurements every second when the transducer is in
contact with the surface of the material. The display is updated as each reading is taken.
4.
Remove transducer from surface
The display will show the last measurement made.
Note: Occasionally, a small film of couplant will be drawn out between the transducer and the
surface as the transducer is removed. When this happens, the gauge may perform a measurement
through this couplant film. This phenomenon can be seen when one thickness value is observed
while the transducer is in place, and another value is observed after the transducer is removed. If
this happens, take the reading again using less couplant.
9 GATES
9.1 INTRODUCTION
The Model PG70ABDL is equipped with gates which control the time measurement process
allowing you to measure a specific region on or between waveforms.
Further information on gates may be found on the Elcometer NDT Knowledge Centre on
www.elcometerndt.com.
