Dakota Ultrasonics
48
7.4 Gain
The gain, or amplification of the return echoes, can be adjusted in the
PVX-B
to
accommodate a variety of applications. The setting of the gain is crucial in order to
obtain valid readings during the measurement process. Too much gain may result in
erroneous measurements, by detecting on noise rather than the actual material back
wall itself. Not enough gain may result in intermittent detection. It may also result in
lack of detection on internal flaws, pits, or porosity. The gain can easily be compared
to the volume control of a home stereo system. If you turn it up too much, you can’t
hear the music clearly. If it’s turned down too much, you can’t hear it at all.
The
PVX-B
has three gain settings
LOW, MED, HIGH)
.
Note:
The
PVX-B
has been
optimized for the
MED
gain setting for all common performance racing applications.
It should be operated in this mode as standard. However, some applications may
require the low or high gain setting. When? The low set ting may be necessary for
certain cast aluminum materials, or very extremely granular cast iron materials. How
do I know when to lower the gain? If the reading becomes sporadic and won’t settle
down or resolve on a thickness value, the user can assume that the material is either
very noisy aluminum, or granular cast iron. This would be a good time to change the
PVX-B
to low gain setting and see if the reading settles down and become stable.
How do I know when to increase the gain? Often times the user will be trying to
measure a material that is hard to penetrate or pass sound through. This may be
due to the material type, or overall thickness of the material. When a material is hard
to pass sound through because of the thickness or general make-up, it would be a
good time to consider switching the
PVX-B
into a high gain setting. In any case, the
selectable gain settings offer the user some additional options to resolve application
issues.
Note:
When the echo-echo thru-paint measurement mode is selected, the gain
manual gain feature is disabled and grayed out in the menu items. In this mode, the
PVX-B
switches to an automatic gain mode
(AGC)
that optimizes the gain setting
automatically in the hardware of the
PVX-B
.
The procedures to adjust the
Gain
are outlined below:
Adjusting the Gain using the Hot Menus
www.
GlobalTestSupply
.com
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