Dakota Ultrasonics PR-82 User Manual

Page 20

Dakota Ultrasonics

Two Point Calibration

NOTE: This procedure requires that the operator has two known

thickness points on the test piece that are representative of the

range to be measured.

1) Make sure the PR-8

is on.

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

3) Apply couplant to the sample piece.

4) Press the transducer against the sample piece, at the first/second

calibration point, making sure that the transducer sits flat against

the surface of the sample. The display should show some

(probably incorrect) thickness value, and the Stability Indicator

should have nearly all its bars on.

5) Having achieved a stable reading, remove the transducer. If the

displayed thickness changes from the value shown while the

transducer was coupled, repeat step 4.

6) Press the CAL key. The IN (or MM) symbol should begin flashing.

7) Use the UP and DOWN arrow keys to adjust the displayed

thickness up or down, until it matches the thickness of the sample

piece.

8) Press the Probe key. The display will flash 1OF2. Repeat steps 3

through 8 on the second calibration point. The PR-8

will now

display the sound velocity value it has calculated based on the

thickness values that were entered in step 7.

9) The PR-8

is now ready to perform measurements.