select the corresponding probe and to set the other DGS parameters:
– Use v to select the function DGSMEN> and then use the right-hand rotary knob to call the DGS menu. Evaluation according to the DGS method (only USM 25S)
– Define your settings: • PROBE-#: probe number
Fixed-programmed probes with all settings
(PRBNAME, DEL-VEL, D eff and PRBFREQ cannot be changed in the case of these probes);
PROBE-# = 0 is user-programmable with reference to all parameters.
• PRBNAME: probe name
The name belongs to the selected probe number and cannot be changed; the individual probe name can be entered only with PROBE-# = 0.
• DGS-CRV: recording curve for DGS evaluation This enables you to select the circular disk-shaped equivalent reflector diameter to be used for displaying the DGS curve and used as recording threshold for echo evaluations.
• DEL-VEL: delay material velocity of the probe; predefined with programmed probes.
• D eff: effective element diameter of the probe used; predefined with programmed probes.
Operation
Double allocation of functions: DGSMEN> DGSMEN>
Calling the DGS menu Switching on/off the DGS evaluation mode T-CORR> OFFSET>
Setting the transfer Activating the multi-curve correction display mode
Default settings for the DGS measurement
In the next step, the DGS menu is called enabling to select the corresponding probe and to set the other DGS parameters:– Use v to select the function DGSMEN> and then use the right-hand rotary knob to call the DGS menu. Evaluation according to the DGS method (only USM 25S)
– Define your settings: • PROBE-#: probe number
Fixed-programmed probes with all settings
(PRBNAME, DEL-VEL, D eff and PRBFREQ cannot be changed in the case of these probes);
PROBE-# = 0 is user-programmable with reference to all parameters.
• PRBNAME: probe name
The name belongs to the selected probe number and cannot be changed; the individual probe name can be entered only with PROBE-# = 0.
• DGS-CRV: recording curve for DGS evaluation This enables you to select the circular disk-shaped equivalent reflector diameter to be used for displaying the DGS curve and used as recording threshold for echo evaluations.
• DEL-VEL: delay material velocity of the probe; predefined with programmed probes.
• D eff: effective element diameter of the probe used; predefined with programmed probes.
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Operation
• PRBFREQ: probe frequency
Frequency of the transducer; predefined with programmed probes.
• REFECHO: type of the reference reflector used BW: backwall
SDH: side drilled hole FBH: flat bottom hole
• REFSIZE: size of the reference reflector
• ATT-REF: sound attenuation in the reference block • ATT-OBJ: sound attenuation in the test object • AMPLCOR: value for the amplitude correction.
This is required whenever you are using an angle probe and the quadrant echo from the calibration standards K1 or K2 as a reference reflector.
Evaluation according to the DGS method (only USM 25S)
Example
In this example, the probe MB 4 S is selected. Refer- ence reflector = backwall, the 3mm circular disc is to be displayed as curve. The sound attenuation correc- tions ATT-REF and ATT-OBJ and the amplitude correc- tion AMPLCOR (for angle probes and calibration standard K1 / K2) remain at 0.
– To return to the A-scan, press one of the following keys: en: E, V, W oder X.
Operation
• PRBFREQ: probe frequency
Frequency of the transducer; predefined with programmed probes.
• REFECHO: type of the reference reflector used BW: backwall
SDH: side drilled hole FBH: flat bottom hole
• REFSIZE: size of the reference reflector
• ATT-REF: sound attenuation in the reference block • ATT-OBJ: sound attenuation in the test object • AMPLCOR: value for the amplitude correction.
This is required whenever you are using an angle probe and the quadrant echo from the calibration standards K1 or K2 as a reference reflector.
Evaluation according to the DGS method (only USM 25S)
Example
In this example, the probe MB 4 S is selected. Refer- ence reflector = backwall, the 3mm circular disc is to be displayed as curve. The sound attenuation correc- tions ATT-REF and ATT-OBJ and the amplitude correc- tion AMPLCOR (for angle probes and calibration standard K1 / K2) remain at 0.
– To return to the A-scan, press one of the following keys: en: E, V, W oder X.
Krautkramer USM 25 Issue 07, 07/2003 5-67
Operation
Evaluation according to the DGS method (only USM 25S)
Recording the reference echo and
displaying the DGS curve
To be able to display the required DGS curve, you have to first record the reference echo.
– You have to start by optimizing the echo of the reference reflector, in this case the backwall echo from the test object.
– Continue by positioning the gate on the reference echo. – Then use v to select the function DGS-REF, and use
the right-hand rotary knob to switch the function on. The message: „Do you want to change the DGS reference echo?“ appears.
– Confirm by pressing v again.
After the successful recording of the reference echo, a highlighted R will be displayed in the measurement line. – Switch the DGS curve on now by using v to select
the function DGSMOD> and by using the right-hand rotary knob to set the function to on.
Taking the general DGS diagram as a basis, the instrument calculates the required test sensitivity for displaying the 3mm curve with its maximum at 80% screen height, and sets this value. The current gain is set to 0 during this. In the case of subsequent gain variations, the curve is automatically adapted.
Operation
Evaluation according to the DGS method (only USM 25S)
Recording the reference echo and
displaying the DGS curve
To be able to display the required DGS curve, you have to first record the reference echo.
– You have to start by optimizing the echo of the reference reflector, in this case the backwall echo from the test object.
– Continue by positioning the gate on the reference echo. – Then use v to select the function DGS-REF, and use
the right-hand rotary knob to switch the function on. The message: „Do you want to change the DGS reference echo?“ appears.
– Confirm by pressing v again.
After the successful recording of the reference echo, a highlighted R will be displayed in the measurement line. – Switch the DGS curve on now by using v to select
the function DGSMOD> and by using the right-hand rotary knob to set the function to on.
Taking the general DGS diagram as a basis, the instrument calculates the required test sensitivity for displaying the 3mm curve with its maximum at 80% screen height, and sets this value. The current gain is set to 0 during this. In the case of subsequent gain variations, the curve is automatically adapted.
5-68 Issue 07, 07/2003 Krautkramer USM 25
Operation Evaluation according to the DGS method (only USM 25S)