GE Phasor 16/16, Operating Manual

Page: 25 / 116

2. Setting Up for Phased Array Measurement
PHASOR XS Operating Manual Page 23
Inputting Part Thickness (PART-PLAN-MAT
THICKNESS)
Step 1: Activate the PLAN Submenu (located in the PART
Menu) by pressing
below it.
Step 2: Press
next to the selection MAT THICK-
NESS.
Step 3: Turn the Function Knob to change the thickness
to match the part under test.
Step 4: The inputted thickness will be set to the last value
displayed.
Specifying Part Material Type (PART-PLAN-
MATERIAL)
Step 1: Activate the PLAN Submenu (located in the PART
Menu) by pressing
below it.
Step 2: Press
next to the selection MATERIAL.
Step 3: Turn the Function Knob or continue to press
until the material type listed matches the part under
test.
Step 4: The longitudinal and shear acoustic velocities will
be set to the average value of the material type displayed.
Note that the displayed values are only an approximate
and should be fine-tuned to more closely match the ac-
tual velocities of sound through the material under test.
Changes to VELOCITY L or VELOCITY S will require
recalculation of delay laws.
Defining the Speed of Sound in the Test Part
(Longitudinal and Shear Velocity) (PART-PLAN-
VELOCITY L or VELOCITY S)
Step 1: Activate the PLAN Submenu (located in the PART
Menu) by pressing
below it.
Step 2: Press
next to either the VELOCITY L or the
VELOCITY S selection.
Step 3: Turn the Function Knob until the velocity listed
matches the speed of sound in the part under test.
Step 4: The longitudinal and transverse acoustic veloci-
ties will be set to the value last displayed. Changes to
VELOCITY L or VELOCITY S will require recalculation
of delay laws.
2.5 Defining the Scan Parameters
NOTE: Modifying certain settings related to probe or
scan configuration will require a recalculation of the
delay laws. When such a change is made, the modi-
fied function will turn red, indicating that the effect of
this change will not take affect until the new delay-law
calculation is carried out. To command a calculation,
press and hold
for three seconds or access the
SCAN PATT submenu and press
next to the CALC
Function.
When operating in Phased Array mode, the sequence
and pattern at which the probe’s elements fire are defined
by the scan parameters (SCAN Menu). This section de-
scribes the process for setting these parameters and the
effect of their settings on the instrument’s function. The
following scan parameters are represented graphically
in
Figures 2-7 and 2-8 and described in greater detail
below:
LINEAR SCAN TYPE – Controlled firing of multiple
elements at a constant angle ( Figure 2-7 )
SECTOR SCAN TYPE – Constant-sized groups of
elements (said to represent a constant “aperture”)
are fired at varying angles (
Figure 2-8 )
FOCAL POINT – Depth into the part at which the
phased array focuses. This depth represents an
area of interest. It can be set to UNFOCUSED (by
holding
for approximately three seconds) for typi-
cal phased-array applications ( Figure 2-9 ).
NOTE : Focal points are valid within the natural
nearfield length N of the selected aperture where:
N = D 2
eff
f
4 c
for circular transducers
N = 1.3 a
2
f
4 c
for square transducers
D
eff
= effective transducer diameter
a = side length of the transducer
f = resonance frequency of the transducer
c = sound velocity in the test object
WAVE TYPE – Indicates whether the user-input
transverse or longitudinal speed of sound should be
used. The setting selected will depend on the probe
type or the type of wave created by refraction when
using a wedge.
SCAN PATTERN – Start, stop, and step angles that
define the incremental angular change followed dur-
ing a sector scan. When performing a linear scan,
the scanning angle remains constant at the value
defined by ANGLE START.
NOTE: A +/-- Sector can be created by setting the
sector scan’s START ANGLE to a negative value and
the scan’s END ANGLE to a positive value.