Starrett SR160 Manuel D'utilisation page 15

ENGLISH
CALIBRATION
Press the calibration button to enter the calibration menu
In the calibration screen, the default or last saved calibration Ra value
will be displayed. To change this calibration value, press the settings
icon. Then use the up (+) and down (-) buttons to adjust the calibration
Ra value to the desired number. Press the back button to accept the value
and return to the calibration screen.
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