Checkline TI-MINIMAX - Manual (Page 91)

MINI-MAX Ultrasonic Bolt Tension Monitor
Chapter 10 Bolt Material Calibration
10.1 Why do we need to calibrate
The preset bolt types in the MINI-MAX contain average factors for the material
type. These are approximate values only. In a tightly controlled application
where extreme accuracy is required, it is necessary to obtain all the information
possible about the fasteners being measured. By calibrating the fasteners, the
ultrasonic and physical lengths of the bolts will match. However, if a field
calibration is done, a complete calibration is not necessary. An important thing to
note is the fact that everything done in the calibration process result in average
values. Since a sample of fasteners will be used in the calibration process, and
given the slight differences in material, the result will always be an average value
of that sample.
10.2 Velocity calibration
A velocity calibration is generally performed by adjusting the velocity in the MINI-
MAX to the point where the ultrasonic and physical lengths match. Again, since
a sample of fasteners will be used in this process, the velocities will vary by a
very small amount, thus resulting in an average velocity value. To accurately
calibrate the velocity, a calibrated set of mechanical calipers is required to
determine the exact physical lengths of the fasteners. The following procedure
outlines this process.
Calibrating the Velocity
1) Press the MENU key once to activate the menu items tab. Press the
MENU key multiple times to tab right, and the ESC key multiple times to
tab left, until the GEOM menu is highlighted and displaying the submenu
items.
2) Use the UP and DOWN arrow keys to scroll through the sub menu items
until QUANTITY is highlighted.