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2. Setting Up for Phased Array Measurement
2.8.2 Selecting the TOF-Detection Method
A-Scan signals crossing a gate are evaluated for the pur-
poses of flaw detection and material-thickness. When the
signal crosses the A or B-Gate, either the gate-crossing
point (flank) of the signal, or the maximum point (peak)
of the signal (in the specific gate) is used for evaluation
purposes. The TOF MODE function allows the user to
specify which A-Scan feature (FLANK or PEAK) is used
to evaluate the signal in the A and B Gates.
Step 1: Activate the GATEMODE Submenu (located in
the UT Menu).
Step 2: Select the gate to be positioned using the GATE
SELECT function.
Step 3: Select the TOF MODE function and choose
between FLANK and PEAK methods.
NOTE: The detection method chosen will be reflected
by the / (flank) or ^ (peak) icons. These icons are
displayed in the display box containing the measured
reading, and in the options offered in the READING 1
through 4 function boxes.
2.8.3 Setting Gate Logic
A TTL output can be set to transmit whenever a user-
selected gate triggers. When a gate-triggering event
occurs, an alarm indication light on the front of the instru-
ment will illuminate and a signal can be output.
Defining Gate-Triggering Logic (UT-GATEMODE-
LOGIC)
The A, B, and IF Gates can be triggered under one of
two circumstances. Gates can be set to trigger when an
A-Scan echo crosses the gate or when no echo crosses
the gate. To specify gate LOGIC settings:
Step 1: Activate the GATEMODE Submenu (located in
the UT Menu).
Step 2: Select the gate to be modified using the GATE
SELECT function.
Step 3: Select the LOGIC function and choose the gate
triggering logic:
•
POSITIVE—An A-Scan signal crosses the gate
•
NEGATIVE—No A-Scan signal crosses the gate
(A and B Gates only)
•
OFF—The selected gate will not be triggered
NOTE: The IF Gate must be turned OFF for the instru-
ment to produce a sector scan.
Page 30
2.8.4 Configure the Gate to Ignore or
Accept Off-Screen Triggers (DISPLAY-
RESULTS2-GATE SHAPE)
Gate triggering can, in some cases, occur at a point that
does not appear on the display screen. The GATE SHAPE
Function determines whether or not off-screen A- or
B-Gate triggers are ignored. To configure the gate
shape:
Step 1: Activate the RESULTS2 Submenu (located in the
DISPLAY Menu) by pressing
Step 2: Press
next to the function titled GATE SHAPE.
Continue pressing
or turn the Function Knob to select
from:
DEPTH BASED – Gate triggers that occur off of the
display screen are ignored
IMAGE BASED – All gate triggers, including those
that occur off screen, are valid
NOTE: When gate width, leg setting, or other param-
eters are configured so that the A or B gate does not
appear on the display screen, changing the GATE
SHAPE setting to IMAGE BASED automatically adjusts
gate width, if required, to keep the gate visible on the
display screen.
2.8.5 Assign TTL Output / Alarm
Indication Light to a Gate (DISPLAY-
RESULTS2-TTL #1)
A warning light appears on the front of the instrument (see
Figure 1-2
for light location). This light corresponds to a
TTL output, which occurs when there is a gate trigger-
ing event. When the A- or B-Gate is triggered, a warning
light illuminates (except when the GATE LOGIC is set to
OFF). Use the following procedure to indicate which gate
activates the light:
Step 1: Activate the RESULTS2 Submenu (located in
the DISPLAY Menu).
Step 2: Activate the TTL #1 function and choose one of
the following selections:
•
A-GATE—Alarm light indicates when A-Gate
triggers
•
B-GATE—Alarm light indicates when B-Gate
triggers
•
A or B—Alarm light indicates when either A or B
gate triggers
•
OFF—Alarm indication light will not function
below it.
PHASOR XS Operating Manual
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