Dakota Ultrasonics PVX - Manual (Page 39)

PVX Precision Visual Thickness Gauge
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6.3 Material Calibration
In order for the PVX to make accurate measurements, it must be set to the correct
sound velocity of the material being measured. Different types of materials have
different inherent sound velocities. For example, the velocity of sound through steel
is about 0.233 inches per microsecond, versus that of aluminum, which is about
0.248 inches per microsecond. If the gauge is not set to the correct sound velocity,
all of the measurements the gauge makes will be erroneous by some fixed
percentage.
The One Point calibration is the simplest and most commonly used calibration
method - optimizing linearity over large ranges. The Two Point calibration allows for
greater accuracy over small ranges by calculating the probe zero and velocity. The
PVX provides four simple methods fo r setting the sound-velocity outlined below:
Calibration to a known velocity
1) Press the MENU key once to activate the menu items tab. Press the MENU
key multiple times to tab right, and the ESC key multiple times to tab left,
until the CAL menu is highlighted and displaying the submenu items.
2) Use the UP and DOWN arrow keys to scroll through the sub menu items
until VELOCITY is highlighted.
3) Press the ENTER key to display the Digits Edit Box.
4) Press the UP and DOWN arrow keys to scroll the highlighted value .
5) Press the LEFT and RIGHT arrow keys to scroll the digit locations.