Checkline TI-CMXDL - Manual (Page 22)

5.0 S ELECTING THE M EASUREMENT M ODE
5.1 The setup library
The TI-CMXDL contains 64 user configurable preset locations to store custom setups for
easy recall. These setups can be optimized for the user’s specific application needs and can
also be stored on a PC and transferred bi-directionally using Dakota’s PC interface soft-
ware included with the instrument.
5.2 Which mode & transducer do I use for my application?
High penetration plastics and castings
The most common mode for these types of applications is pulse-echo. The TI-CMXDL has
been optimized for cast materials. Cast iron applications require 1 - 5MHz frequencies, and
cast aluminum requires a 10MHz frequency. Plastics typically require lower frequencies
depending on the thickness and make-up of the material. Larger diameters offer greater
penetration power because of the crystal size, for difficult to measure materials.
Corrosion & Pit Detection in steel and cast materials
Use pulse-echo mode whenever attempting to locate pits and flaws. Typically a 5MHz
transducer, or higher, will be used for these types of applications. Use low frequencies for
greater penetration and use higher frequencies for better resolution.
Measuring Material & Coatings
The pulse-echo coating mode should be used when both material and coating thickness are
required, while still requiring the ability to detect flaws and pits. A special coating style
transducer is required for use in this mode. There are a variety of coating transducers in
various frequencies available from Electromatic.
Thru Paint & Coatings
Often times, users will be faced with applications where the material will be coated with
paint or some other type of epoxy material. Since the velocity of the coating is approxi-
mately 2.5 times slower than that of steel, pulse-echo mode will induce error if the coating
or paint is not completely removed. By using echo-echo mode, the user is able to success-
fully measure through both, the coating and steel, and completely eliminate the thickness
of the paint or coating. Therefore, the steel can be measured without having to remove the
coating prior to measuring. Users will often use pulse-echo mode and echo-echo mode in
conjunction when performing inspections on coated materials.
Thru coating measurements require special high damped transducers. The most common
transducers are the 3.5, 5, and 7.5MHz hi damped transducers. These transducers are
suitable for use in both pulse-echo and echo-echo modes. This conveniently enables the
user to accurately measure overall material thickness using the thru Coating mode, and
then conveniently switch to pit detection mode without changing transducers. The _”
5MHz Hi damped transducer is the most commonly used transducer for standard thru
coating applications.
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3. Press the LEFT and RIGHT arrow keys to scroll the digit locations.
4. Repeat steps 2 & 3 until the DIFFERENTIAL value is correctly displayed.
5. Press the OK key to set the DIFFERENTIAL value and return to the menu screen.
6. Finally, press the MEAS key to return to the measurement screen and begin
taking readings.
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