Checkline TI-CMXDL - Manual (Page 30)

Two Point Calibration
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 trans-
ducer 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 2PT 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
correct, repeat the steps above.
Basic Material Type
If the material velocity is unknown, and a sample thickness cannot be taken from the ma
rial, the user may opt to choose a basic material type from a list with approximate veloc
values according to various material types. It’s important to note that these velocities wi
not always be an exact representation of the material being tested. Use these values only
a close approximation is acceptable. Follow the steps below to select a basic material typ
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 CAL menu is
highlighted and displaying the submenu items.
2. Use the UP and DOWN arrow keys to scroll through
the sub menu items until MAT is highlighted.
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9.0 P ULSE -E CHO C OATING & C OATING T ECHNIQUES
9.1 Introduction to Pulse-Echo Coating Measurement (PECT)
In the previous sections we’ve discussed the need for detecting pits and flaws (pulse-echo)
in materials, along with the requirement to measure through and eliminate errors caused by
coated materials (echo-echo). Until now, both modes were needed in order accomplish both
tasks. Pulse-echo mode was used for flaw detection, and echo-echo mode was used to elim-
inate the coating thickness and provide a nominal material thickness only. With this in
mind, it often became cumbersome toggling between both modes respectively.
In a majority of applications involving coated materials, inspectors are often interested in
monitoring both the thickness of the material, as well as the thickness of the coating.
Therefore, the TI-CMXDL has been designed to provide the user with the ability to meas-
ure the material and coating thicknesses simultaneously, while maintaining the ability to
detect flaws and pits all in a single mode called Pulse-Echo Coating (PECT). This is
accomplished by using a custom hybrid combination mode utilizing properties from the
basic modes along with a group of special techniques and theoretical wave phenomena’s.
The TI-CMXDL is preset to a coating velocity of 0.0850 in/µsec (2159 m/sec) from the
factory. This velocity is a very close approximation of the common coating velocities found
in the field. However, the TI-CMXDL also has a built-in one and two point calibration
options to calibrate to coating samples with a known thicknesses.
There are two coating modes built into the TI-CMXDL:
1. Pulse-Echo Coating (PECT) – used during inspections where both the material
and coating thicknesses are required.
2. Coating Only (CT) – used during inspections where only the coating thickness is
required.
9.2 Enabling Pulse-Echo Coating Mode (PECT) & Coating (CT)
When the TI-CMXDL is initially powered up, the gauge will automatically check to see if
the transducer plugged into the gauge can be recognized. All Dakota Ultrasonics coating
enabled transducers are equipped with the auto recognition feature. If the TI-CMXDL
doesn’t recognize that a special coating enabled transducer is plugged into the gauge, the
coating feature will be disabled entirely. There are a number of coating enabled transducers
available from Dakota. Please contact us with your application requirements for additional
information on frequencies and diameters currently offered.
The coating modes can be enabled in three different ways:
1. On Power up and probe recognition.
2. By pressing MULTI MODE keypad.
3. From the tabbed menus under TUNE, MEASURE MODE.
The steps that follow will demonstrate all three methods in the order listed above.
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