26
en
2.
Press MEAS.
The measurement screen is displayed.
3.
In the hot menu, adjust the value of the LOC function to A1 (row 1 for the first sample bolt, row 2 for the
second sample bolt, etc.)
4.
Apply the transducer and couplant to the bolt and press ENTER.
The ultrasonic length at no load is measured and saved in cell A1.
5.
Use the load apparatus to apply approximately 1/3 of the maximum load which is to be placed on the
bolt under actual working conditions.
6.
If necessary, in the hot menu, adjust the value of the LOC function to B1 (If the group automatic
increment direction function INCR. DIR has been set to EAST, the value of LOC will be adjusted to B1
automatically).
7.
Keeping the transducer in exactly the same position, press ENTER.
The ultrasonic length at load 1 is measured and the Digits Edit Box is displayed.
8.
Adjust the value in the Digits Edit Box until it matches the known load (from the load apparatus):
•
Press OK to store the known load value and return to the measurement screen, or ESC to cancel.
9.
Repeat steps 5 to 8 with the load on the bolt increased to 2/3 of the maximum which is to be placed on
the bolt under actual working conditions. Store this known load value in group cell location C1.
10. Repeat steps 5 to 8 with the load on the bolt increased to the maximum which is to be placed on the
bolt under actual working conditions. Store this known load value in group cell location D1.
11. Repeat steps 1 to 10 for sample bolt 2. Store the values in group cells A2 to D2.
12. Repeat steps 1 to 10 for sample bolt 3. Store the values in group cells A3 to D3.
11.3.5 Calculate the load factor
1.
Select MENU/CAL/LOAD CAL. CALC
2.
Press ENTER.
The vector or regression calculation is performed and the coefficient is displayed.
Note: The closer this number is to 1, the better the fit, or least amount of error.
3.
Press OK to accept the calculation, or ESC to cancel and return to the CAL menu.
4.
Press MEAS to return to the measurement screen.
Calibration is now completed.
Note: The new LOAD FACTOR and LOAD OFFSET values can be reviewed and edited at any time: Press
MENU and then scroll to the GEOM menu.
12 MEASUREMENT - TAKING READINGS
Disclaimer:
Inherent in ultrasonic thickness measurement is the possibility that the instrument will use the
second rather than the first echo from the end of the bolt being measured. This may result in a length
reading that is TWICE what it should be.
Responsibility for proper use of the instrument and recognition of this phenomenon rests solely with the user
of the instrument.
Other errors may occur from measuring coated bolts where the coating is insufficiently bonded to the bolt
surface. Irregular and inaccurate readings may result. Again, the user is responsible for proper use and
interpretation of the measurements acquired.
12.1 BEFORE YOU START
•
Prepare the surface of the bolt - see “Bolt Preparation” on page 5.
•
If necessary, set the zero point of the transducer - see “Measuring System Zero (Calibration)” on
page 11.
•
If necessary, calibrate the gauge - see “Bolt Material Calibration” on page 18.
•
Choose the measurement view (RF, RECT or DIGITS) - see “Measurements and The Measurement
Screen” on page 7.
