Panametrics MG2, User Manual, Page: 22 / 138

910-257C March 2006
Page 3-4 MG2 Series
Note: Cal Velocity should always be performed on the thick
sample and Cal Zero should always be performed on the
thin sample.
Note: Before calibrating, the measured thickness value while
coupled to the thin calibration block should be /
- 0.010 inch or +\- 0.20 mm of the correct thickness. If
the indicated thickness is two or more times the actual
thickness of the thin calibration block with a good
approximate sound velocity, the gage is “doubling”, that
is, measuring to the 2
nd
or 3
rd
multiple echo. Do not
attempt to do a Velocity and Zero calibration under this
condition. Doing so will cause an error. Instead, correct
the cause of the doubling. Either the calibration block is
thinner than the specified capability of the transducer,
the transducer is malfunctioning, or the gage is malfunc-
tioning.
3.4 Material Velocity
Calibration
3.4.1 When Material Sound Velocity Is
Unknown
To do the Material Velocity Calibration, a calibration block made from
the material to be measured must be used. The block should be
approximately as thick as the thickest section to be measured and have
flat, smooth, and parallel front and back surfaces. The thickness of the
block must be known exactly.