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1. Start the Velocity application by clicking the icon (Velocity 2.0.5) on the desktop.
2. Once the application is launched, click the Make a Measurement button.
3. In the Scan Sample Label dialog box, place the cursor in the Scanner String field (Figure 25).

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Figure 25. Scan Sample Dialog Box.

4. Scan the barcode on the section half label to populate the fields on the Scan Sample Label dialog box. Enter Operator (user last name) and confirm measuring Station and Mode.

Stations Bayonet Y and Bayonet Z are for soft sediments. To use a Bayonet measuring station, the Mode value must be Section w/liner (material is still in core liner). Note: The orientation assigned to the sample measurement depends on the Station selected.

5. For Section w/liner mode, a Position Sample dialog box opens (Figure 26). Confirm the sample position as measured by the laser (the laser at the end of the track measures the range to the end of the core and calculates the position in the liner based on an offset for that station). Click OK.

Image Added Section-half measurements, in the liner. (X-Axis)Section-half measurements, in the liner. (X-Axis)Discrete sample (MAD cubes) measurements. (Z-Axis)Discrete sample (MAD cubes) measurements. (Y-Axis)Discrete sample (MAD cubes) measurements. (X-Axis)Piece measurements taken out of the section-half. Consolidated material only. (Any-Axis)Section-half measurements, in the liner. (X-Axis)

Figure 26. Position Sample Dialog Box.

6. The bayonet transducers lower into the section half; ensure they are completely inserted into the sample. If contact between the transducers and sediment is poor, add distilled water around the transducers to improve contact with sediment.

7. On the JOG Bayonet screen (Figure 27), monitor the waveform and position the transducer to obtain the best trace. The plot displays the live signal with no stacking. A weak signal is fine, as long as a clean first arrival is present. Once the waveform is acceptable, click Continue to begin sample acquisition.

Figure 27. JOG Bayonet Y Screen.

8. During acquisition, the program adds multiple waveforms until the total (max peak) is greater than ±5 V. This process is repeated and the waveform is averaged.

Measuring Discrete Samples

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1. Start the Velocity application by clicking the icon (Velocity 2.0.5) on the desktop.
2. Once the application is launched, click the Make a Measurement button.
3. In the Scan Sample Label dialog box, place the cursor in the Scanner String field (Figure 28).

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Figure 28. Scan Sample Label Dialog Box.

4. Scan the barcode on the discrete sample label to populate the fields on the Scan Sample Label screen. Enter Operator (user last name) and confirm measuring Station (Caliper) and Mode (Discrete).

5. Enter information requested in the Additional Discrete Information dialog box (Figure 29): Measurement Axis: X, Y, or Z.

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Figure 29. Additional Discrete Information Dialog Box.

6. If the material to be measured is a whole piece removed from the liner (rarely used), select Piece w/o Liner mode in Step 4 and complete the offset (position of the piece in the liner before it was removed) in the Additional Piece Information dialog box (Figure 30).

If the orientation of the piece is unknown, check the Orientation Unknown box; otherwise the measurement is assigned to the X-direction.

Figure 30. Additional Piece Information Dialog Box.

7. Place the discrete sample in the caliper and add distilled water to create a good sample-transducer contact if needed.

8. On either the Additional Discrete Information (discrete samples) or Additional Piece Information (piece samples) box, select OK - AutoClose (for hard samples) or OK – Manual Close (for softer/friable samples).

AutoClose automatically closes the caliper on the sample. The transducer moves to a predefined position or until the actuator stalls.

9. On the JOG Caliper screen (Figure 31), monitor the waveform and position the transducer to obtain the best trace. The plot displays the live signal with no stacking. A weak signal is fine, as long as a clean first arrival is present. Once the sample is properly positioned, click Continue to begin sample acquisition.

Figure 31. JOG Caliper Screen.

10. During acquisition, the program adds multiple waveforms until the total (max peak) is greater than ±5 V. This process is repeated and the waveform is averaged.

The touch-screen Open/Close commands may be sluggish in response. If there is no response, try actuating the button using the mouse.

11. Repeat the measurement process for each axis to be measured.

Accepting Results and Manual Pick

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Figure 33.A Manual Pick Screen. 

2. Click Continue to accept the manual pick and save it to the data file or Cancel to discard the manual pick results.

Data Handling

From the Display Results screen one of 4 data handling choices can be selected:

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The following are common problems encountered when using the P-wave Velocity Gantry and their possible causes and solutions. For information about the laser Measurement and Operation software, see the Vp GIESA Gantry Laser Operation manual.

 Actuator Utilities

The actuator utilities can be used to test the caliper and bayonet actuators (move them up and down) and view the waveform detected by the transducers. There are also utilities to test the home position of the actuators and to check the laser function. This utility is useful when configuring the station offsets.

To change the behavior and/or force of the actuators, the Exlar utility must be used.

Open the Actuator utility (Figure 35) from Main > Actuator Utility and then select one of the JOG screens, Home All, or Read Laser.

Figure 35. Actuator Utilities.

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