Check-line TI-CMX User Manual page 17

9.3 Coating Calibration (PECT)
Known Velocity
If the coating velocity is known, the user may wish to simply enter the velocity number
into the TI-CMX, rather than have the TI-CMX calculate the velocity value using a known
thickness on a coating sample(s). The steps for entering the velocity are outlined below:
Using a Known Material 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 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 COATING VEL is highlighted.
3. Press the ENTER key to display the Digits Edit Box.
4. Press the UP and DOWN arrow keys to scroll the highlighted
value.
5. Press the LEFT and RIGHT arrow keys to scroll the digit
locations.
6. Repeat steps 4 & 5 until the velocity number is correctly
displayed.
7. Press the OK key to set the velocity and return to the menu
screen, or ESC to cancel entering the velocity.
8. Finally, press the MEAS key to return to the measurement screen and begin taking
readings.
Known Thickness
Sometimes the sound velocity of a coating material is unknown. In this case a sample with
a known thickness can be used to determine the sound velocity of the coating. As previous-
ly discussed, the TI-CMX offers a one point calibration option for coating in PECT meas-
urement mode. It is also import to reiterate that the coating sample must be coupled to a
metallic material in order to perform the calibration. The calibration should also consider
calibrating on high side of the intended measurement range, when using the one point
option, minimize overall error. For example, if the measurement range of the coating will
be from .040" - .080" (1.0mm 2.3mm), a coating closest to .080 (2.0mm) should be used.
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 coating using a set
of calipers or a digital micrometer.
NOTE: The coating sample must be coupled to a metallic material
in order to be calibrated.
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Probe Zero Disk & Battery Cover
Refer to Diagram: The Battery cover is the large round disk shown in the diagram. Not
This same disk is also used as a probe zero disk. Simply remove the cover when replacin
the batteries (3 AA cells). When performing a manual probe zero function, simply place
transducer on disk making firm contact.
IMPORTANT: Be sure to follow the polarity labels located on the back label of the
TI-CMX.
NOTE: Rechargeable batteries can be used, however they must be recharged outside of
unit in a stand alone battery charger.
RS-232 Connector
Refer to Diagram: The RS-232 connector, located on the bottom end cap, is a 2 pin
female Lemo connector. It is designed to connect directly from the TI-CMX to a standar
AT serial port on a PC. The cable supplied with the TI-CMX is a Lemo to 9 pin serial
cable. Note: This connector is also used to upgrade the TI-CMX with the latest version o
firmware.
USB Serial to USB Converter Cable
A converter cable can be attached to the 9 pin serial cable in needed (part no. N-402-05
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