Olympus 45MG, User Manual

Page: 65 / 246

DMTA-10022-01EN, Rev. C, January 2015
Basic Operation 55
5.2.1 Calibrating the Instrument
To make accurate measurements, you need to perform the following calibrations:
• Material sound velocity calibration
• Zero calibration
The calibrations must be performed using a thick and a thin sample of precisely
known thicknesses. The sample must be made of the same material as the parts to be
inspected (see “Test Blocks” on page 58 for details on test blocks).
The following procedure is illustrated using a dual element probe and a five-step test
block. Refer to “Calibration” on page 54 for more details on the calibration process.
To calibrate the instrument
1. To perform the material sound velocity calibration using an instrument with or
without the Waveform software option (see Figure 5-5 on page 56):
a) Place a drop of couplant on the surface of the thick part of the test block.
b) Couple the transducer to the thick part of the test block using moderate to
firm pressure (see Figure 5-4 on page 55).
The waveform (optional) and the thickness reading appear on the screen.
c) Press [CAL VEL] .
d) Once the thickness reading is stable, press [ENTER] .
e) Using the arrow keys, edit the thickness value to match the known thickness
of the thick part of the test block.
Figure 5-4 Sound velocity calibration on a five-step test block — Thick part
12.7 mm (0.500 in.)