Checkline TI-CMX - Manual (Page 27)

(2.54mm) to 1.0” (25.4mm), the user should calibrate on a known thickness sample
close to 1.0” (25.4mm).
NOTE: It’s always handy to carry a set of mechanical calipers to use in conjunction
with the TI-CMX for calibration in the field:
One Point Calibration
NOTE: Be sure that the probe zero procedure has been performed prior to performing
this calibration procedure.
1. Physically measure an exact sample of the material or a
location directly on the material to be measured using a set
of calipers or a digital micrometer.
2. Apply a drop of couplant on the transducer and place the
transducer in steady contact with the sample or actual test
material. Be sure that the reading is stable and the
repeatability indicator, in the top left corner of the display, is
fully lit and stable. 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 CAL
menu is highlighted and displaying the submenu items.
3. Use the UP and DOWN arrow keys to scroll through the sub
menu items until MATL 1PT is highlighted.
4. Press the ENTER key to display the Digits Edit Box.
5. Press the UP and DOWN arrow keys to scroll the highlighted
value.
6. Press the LEFT and RIGHT arrow keys to scroll the digit
locations.
7. Repeat steps 5 & 6 until the known thickness value is
correctly displayed.
8. Press the OK key to calculate the velocity and return to the menu screen, or ESC to
cancel the one point calibration.
9. Finally, press the MEAS key to return to the measurement screen and begin taking
readings.
NOTE: CHECK YOUR CALIBRATION! Place the transducer back on the calibration
point. The thickness reading should now match the known thickness. If the thickness is
not correct, repeat the steps above.
At some point there may become a requirement for improved accuracy over a smaller
measurement range. In this case, a two point calibration would be most suited for the
job. For example, if the measurement range was .080” (2.03mm) to .250” (6.35mm), the
user would perform a one point calibration on a known thickness sample close to .250”
(6.35mm), followed by a two point calibration close to .080” (2.03mm). When a two
point calibration is performed, the TI-CMX calculates the zero and the velocity.
The following steps outline this procedure:
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7.0 U SING THE D IGITS AND B-S CAN D ISPLAYS
A key feature of the TI-CMX is the ability to toggle between two different display options,
Digits and B-Scan. The Digits view provides the user with a large digital readout of the thick-
ness. Both views also include a scan bar features that uses a bar graph to indicate thickness.
The Scan bar can be very handy while scanning a tank or pipe wall by graphically displaying
deflections from pits or internal flaws, rather than having to constantly watch for changes in
the digital readout. It’s just another visual aid to alarm the user when something out of the
ordinary has been detected.
The B-Scan display is also very useful when scanning surfaces and viewing the cross section
of the test material. It provides a convenient way of visually profiling, or drawing a picture of,
the blind surfaces during a scan. The B-Scan display is also equipped with a scan bar repre-
senting the overall thickness. Once again, the scan bar gives the user a visual indication when a
flaw or defect has been passed over during the scan process. The scan bar will deflect off of
the defect and return back to the overall thickness. In this chapter we’ll outline some of the
fine adjustment features of the TI-CMX. We’ll take a better look at these options in this
chapter.
NOTE: In order to recall and use the new adjustments made to the TI-CMX at a later time, the
user must save the modified settings in one of the setup locations. Refer section 11.0 for more
information on setups.
7.1 Display Views
DIGITS
The Digits view is a basic digital
thickness gauge look and feel. The
larger digits make it much easier for
the operator to monitor the thickness
readings. The Scan Bar has also been
added to the Digits view to provide
the user with yet another visual tool
for easily monitoring changes in
thickness readings due to internal
flaws or defects.
The following is a list of the view-
able features on the display:
A. Repeatability/Stability Indicator – This indicator should be commonly used in
conjunction with the digital thickness values displayed. When all the vertical bars are
fully illuminated and the last digit on the digital thickness value is stable, the
TI-CMX is reliably measuring the same value 3 to 200 times per second, depending
on which measurement mode and features are enabled.
B. Battery Icon – Indicates the amount of battery life the TI-CMX has remaining.
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