FD700 & FD800 Flaw Detectors - Features Explained

 

FD700 & FD800 Tool Kits

 

 

Zero Crossing

Zero Crossing

 

The gate detects the flank of the pulse, but the measurement is taken at the next crossing of the x axis. This is the most common type of detect in ultrasonic measurement.

Flank

Flank

 

The gate is triggered by the flank (or side) of the pulse on the graph and the measurement taken at this exact point.

 

 

 

 
Peak

Peak

 

The gate is triggered by the intersection with the A-scan pulse and the detection is taken from the next peak in the signal (when it stops rising and starts falling).

TCG

TCG

 

Time corrected gain increases gain as distance increases, in order to achieve an overall level of sensitivity for the same flaw/reflector at different distances.

 

 

 

 
DAC

DAC

 

Distance amplitude correction for the creation of DAC curves which allow the operator to compare flaws of the same size at different depths.

AWS

AWS

 

The American Weld Standard function provides automatic defect sizing in accordance with AWS D1.1 structural welding code.

 

 

 

 
DGS/AVG

DGS/AVG

 

Allows automatic defect sizing from a single reference defect.

   

  

 

FD700 & FD800 Measurement Modes Explained

 

 

Pulse - Echo Mode (PE):
The normal display mode, measures the total thickness from the base of the transducer probe to the material density boundary (typically the back wall). Ideal for pit and flaw detection.
   
Pulse - Echo Temp Comp Mode (PETP):
Similar to the PE mode, PETP takes into account and compensates for the variations in measurement caused by temperature variations.
   
Echo - Echo Mode (EE):
Also known as the ThruPaint™ Mode, EE ignores the coating thickness, displaying the material thickness from the top surface of the material to the material density boundary.
   
Echo - Echo Verify Mode (EEV):
The echo-echo verify mode measures by comparing the values between 3 reflections and is mainly used to eliminate errors from surface coatings and to make measurements in multiple layered materials.
   
Coating Only Mode (CT):
Displays the thickness of the coating applied to the material.
   
Pulse - Echo Coating Mode (PECT):
Displays both the material thickness (PE) and the coating thickness (CT) at the same time.

 

 

FD700 & FD800 Display Modes Explained

 

 

CG70 B-Scan

Material Thickness Digits Display:

The standard display on all models, this displays the numerical thickness value in either millimetres (MM)or inches (IN).

 

Scan Bar Display:

A linear graphic display which allows users to graphically monitor changes in thickness readings. As the scale range can be adjusted by the user, this display is ideal for observing tiny variations in material thicknesses.

 

B-Scan Display:

A time based cross sectional 2D block view of the thickness provides a graphical view of the material thickness - ideal for relative depth analysis.

   
CG70 A-Scan

A-Scan Display; Full Wave (RF):

The A-Scan display shows the sine wave created by the reflected sound, or oscillation, from the material being measured. In RF mode the full wave form is displayed.

 

A-Scan Display; Rectified (+ or -):

Users can select to view either the positive or the negative cycle of the full waveform (RF). This rectified (RECT) display shows the amplitude of the echo versus the transit time.

 

 

DAC

Flaw Mode:

This mode enables inspectors to locate porosity, defects, inclusions and cracks in a variety of test materials. The sound wave is introduced into the test material at a specific angle, and converted from a longitudinal wave into a shear wave. The introduction at specific angles enables inspectors to steer the sound wave in a specific direction according to the position and location of specific types of defects.

 

 

FD700 & FD800 Features Explained

 

Repeatability / Stability Indicator
Consisting of 6 vertical bars, when all the bars are fully illuminated and the last digit on the digital thickness value is stable, the gauge is reliably measuring the material thickness.

 

High Speed Scan with Minimum Thickness Display
By significantly increasing the measurement refresh rate this mode allows the user to make scanned passes over the test material. The smallest thickness value is held in memory and displayed when scanning is complete. This feature can also be used in conjunction with the minimum & maximum limit alarm feature (model dependant).

 

Differential Mode
Once a user defined nominal thickness value has been set, the gauge will display the +/- thickness difference from the nominal value entered.

 

Limit Alarm Mode
The user can define minimum and maximum thickness limits. If the measurement falls outside the upper or lower limit a red LED will light and the beeper sounds. A green LED will light to indicate an acceptable thickness.

 

V-Path CorrectionV Path Correction

Dual element transducers consist of a probe with two crystals (one to transmit and one to receive the sound pulse). The crystals are separated by an acoustic barrier - generating a 'V-shaped' sound path as the sound travels from one element to the other.
This path is slightly longer than the direct path therefore V-path correction is used to calculate the correct thickness.