Calibrating The Instrument - Olympus 38DL PLUS User Manual

zero compensation is responsible for that task (see "Calibrating the Instrument"
on page 67 and "Material Sound Velocity and the Zero Calibrations" on page 71).
5.2.1

Calibrating the Instrument

When you want to make accurate measurements, you need to perform the following
calibrations:
• Material sound velocity calibration
• Zero calibration
You must perform the calibrations 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 70 for details on test blocks).
The following procedure is illustrated using a dual element probe and a 5-step test
block. Refer to "Calibration" on page 66 for more details on the calibration process.
To calibrate the instrument
1. To perform the material sound velocity calibration (see Figure 5-4 on page 68):
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.
The waveform and the thickness reading appear on the screen.
c) Press [CAL VEL].
d) When the thickness reading is stable, press [ENTER].
e) Using the arrow keys, edit the thickness value to match the known thick
thickness of the test block.
DMTA-10004-01EN, Rev. D, November 2016
Basic Operation 67