Sometimes the object of the measurement is not the metal but what protects it. Coating Only mode isolates the applied layer and returns its thickness.
- ✓ Measurement of the protective layer alone, separate from the substrate
- ✓ Checks that the applied system matches the one specified
- ✓ Checking the uniformity of application on large surfaces
- ✓ On the CMX series the declared range is 0.0127 – 2.54 mm
A protective coating is not a cosmetic detail: it is what separates the metal from the aggressive environment. Its thickness is prescribed by the paint system, and a layer thinner than intended reduces protection while a thicker one can introduce adhesion and mechanical behaviour problems.
Coating Only mode, indicated as CT, isolates this information. Unlike PECT, which returns metal and coating together, here the reading concerns the applied layer alone: it is the mode for those checking a painting job, not the state of preservation of the wall.
Need help choosing the right product?
On the CMX series the range declared by the manufacturer for coating measurement goes from 0.0127 to 2.54 mm. As with all ultrasonic measurements, the result depends on calibration: the coating has its own propagation velocity, different from that of the underlying metal, and it must be set separately.
Three modes, three different answers
| Mode | Reading result |
|---|---|
| Echo-Echo | Metal only, coating excluded |
| PECT | Metal and coating, two values in the same reading |
| CT — Coating Only | Coating only |
| Pulse-Echo | Metal and coating added together in a single value |
| Calibration required | Coating velocity, separate from that of the metal |
Who uses it and for what
The most common case is the acceptance testing of a protection system: checking that the applied thickness matches the one prescribed by the specification, and that it is uniform over the whole surface rather than concentrated where the operator’s hand passed several times.
The second case is maintenance: following the degradation of the protective layer over time to schedule its renewal before the metal is left exposed. In both cases the measurement usefully combines with that of the substrate, obtained with PECT in the same pass.
Instruments with Coating Only mode
| Instrument | Typical use |
|---|---|
| Dakota CMX1-DL | Metal and coating, with dedicated Coating Only mode |
| Dakota CMX2-DL | The same modes with waveform verification |
| Dakota CMX10-DL | Top of the range with six modes and colour A-Scan |
| Calibration blocks | References for adjusting the instrument |
Frequently asked questions
On the CMX series the manufacturer declares a range from 0.0127 to 2.54 mm for coating measurement. The value is given in the datasheet of each model.
Yes. The coating has its own propagation velocity, distinct from that of the metal substrate, and it must be set separately on the instrument.
Yes, with PECT mode, which returns both values at the same time. Coating Only is instead for when only the applied layer matters.
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Further information and contacts
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More information about RODER SRL : about us
Contact for general information : info@roder.it
Contact for information about these products : info@roder.it
The information contained on this web page is provided for information purposes only. Although it has been compiled with the utmost care, it does not constitute a contractual offer or a binding commitment to supply. It may contain transcription, translation or typographical errors. For precise and up-to-date information, please contact our company directly.
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