Dakota Ultrasonics MMX-6 User Manual

Page 18

Dakota Ultrasonics

point calibration is the simplest and most commonly used calibration

procedure - optimizing linearity over large ranges. The two point

calibration allows for greater accuracy over small ranges by calculating the

probe zero and velocity. The MMX-6 provides three simple methods for

setting the sound-velocity, described in the following pages.

Note: Although the MMX-6 has a thru-paint/coating feature, one and two

point calibrations must be performed on material with the paint or coating

removed. Failure to remove the paint or coating prior to calibration, will

result in a multi material velocity calculation that may be different from the

actual material velocity intended to be measured.

Calibration to a known thickness

Note: This procedure requires a sample piece of the specific material

to be measured, the exact thickness of which is known, e.g. from

having been measured by some other means.

1) Make sure the MMX-6 is on and switched to P-E (pulse-echo)

mode. Press the Dual-Multi key to toggle modes.

Note: The calibration function has been disabled in E-E (echo-echo)

mode. If the CAL key is pressed while in E-E mode, “nO” followed by

“CAL” will be displayed.

2) Perform a Probe-Zero (refer to page 12)

3) Apply couplant to the sample piece.

4) Press the transducer against the sample piece, making sure that

the transducer sits flat against the surface of the sample. The