April 2009
9-12
Servicing the PT878GC
Calibrating the Thickness Gauge Transducer
To zero the transducer offsets, go to the Zero tab. Press the [
W
] or
[
X
] arrow key until you reach the Zero tab and press
[ENTER]
. The
screen appears similar to Figure 9-9 below.
Figure 9-9: The Zero Window
1.
Press the [
T
] arrow key to enter the window.
2.
The first prompt asks you to choose between single and dual-
point calibration. Use the [
W
] and [
X
] arrow keys to move to
the appropriate radio button and press
[ENTER]
.
Note:
GE Sensing recommends dual calibration. Dual-point
calibration is more reliable, but it requires two known
thicknesses of the calibration material.Use single-point
calibration only if you know the sound speed in the
calibration block material to a high degree of accuracy.
See Appendix C for more information.
3.
The next prompt asks you to enter the length of Block 1. (If
you are using a GE Sensing-supplied test block, the length is
printed on the block.) Press
[ENTER]
to open the text box.
Display
Thickness Gauge Measure
Cancel
OK
Graph
Velocity
Zero
Material
Block 1 Length
Calculated
Current
Transducer Delay,
0
0
Single
Dual Calibration
0
mm Calibrate
µs