Checkline TI-MVX - Manual (Page 19)

3.13 OK Key
The primary function of the OK key is confirmation of a change or
selection.
3.14 ESC Key
The ESC key is used in the MENU, MEAS, and EDIT functions as a back or
escape function.
3.15 Arrow Keys
The Arrow Keys are used to navigate through the menus, increase/decrease val-
ues, and toggle specific function keys.
3.16 ENTER Key
The ENTER key is used in the overall menu selection process, to
activate list and edit boxes, and save measurements to grid locations.
3.17 MULTI MODE Key
The MULTI MODE key toggles the measurement mode of the TI-MVX, from
pulse-echo (flaw mode), to echo-echo (thru paint) mode. This is a quick
automatic preset mode that enables the user to change modes without
having to manually adjust the view and gate parameters. Both modes
have been configured for use with any transducer type selected.
3.18 ON/OFF Key
The ON/OFF key simply powers the unit either ON or OFF.
Note: Unit will automatically power off when idle for 5 minutes.
All current settings are saved prior to powering off.
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cycle altogether. This peak jump represents a
shift of the detection further out in time, result-
ing incorrect measurements. The material being
measured will appear thicker than it actually is.
Refer to the diagram:
Notice the +/-positions in the diagram.
The positive phase is everything above the
horizontal center line, and the negative every-
thing below the center line. The TI-MVX uses a
zero crossing (flank) method for detection.
Therefore, the detect line (A) is represented by
the broken vertical dotted line, and is currently detecting on the negative portion
of the waveform (B) at the zero crossing (C). The signal amplitude (B) is shown
as the negative vertical height at (B) in the diagram. Refer to the height of the
second negative peak at (G). It’s clear that the amplitude of (G) is much greater
than that of (B). Therefore, if the user was measuring thick attenuative material,
and the amplitude of (B) decreased substantially, the TI-MVX would lose the first
cycle (B) and peak jump to the second cycle (F). The detect (A), would move to
(F), resulting in incorrect measurements.
If the user were to select the positive phase in the diagram above, the detect
would measure at (H). (A) would move to (H). Notice the height of (D) with
respect to the height of (E) in the diagram. If the user was measuring thick atten-
uative material using this phase, the signal (E) will certainly be lost long before
(D). Therefore, the positive phase is a much better choice in the diagram above.
Toggle Polarity (+/-)
Note: Before toggling the Polarity, the TI-MVX
should be set to the RF display view option.
The RF view will give the user the best
opportunity to correctly view the positive and
negative cycles of the waveform. Please refer
to page 38 for information on selecting the
Display Views.
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 TUNE menu is highlighted and displaying the submenu items.
2) Use the UP and DOWN arrow keys to scroll through the sub menu items until
POLARITY is highlighted.
3) Use the LEFT and RIGHT arrow keys to toggle the POLARITY negative or
positive.
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