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PDF data sheet
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The laser beam of the scanning laser doppler vibrometer is deflected by 2 mirrors which are controlled by the computer. A camera inside the head delivers the picture of the object under test. On this picture the measurement points can be arranged like with a CAD software. After the setup of points the measurement is done automaticly by the computer. |
Method
The scanning laser vibrometer is based on the single point laser vibrometer VibroMet500. The laser beam measures the velocity on the surface of the test object. The velocity signal is measured by a data aquisition system and stored in the computer.
Components
In the picture above the components of a laser scanning system are displayed.
- Laser head with mirror unit
- Controller box
- Data aquisiton
- Laptop with control and analysis software
The complete system is very compact and can be carried by on person for example when using a plane.
Laser head
The laser head includes the laser unit, the mirrors and the video camera. An adjustment of any lenses or optical system is not necessary. The mirrors are controlled by the computer.
Controller
The components inside the controller box are the RF amplifier, the demodulator and the output filter. The amplifier increases the signal level, the demodulator makes a velocity signal out of the Doppler signal and with the output low pass filter the frequency range can be limited to reduce noise etc.
Data aquisition
The data aquisiton unit for the laser scanner is available as an internal PCI card or as an external USB box.
| Technical data |
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| Number of channels: |
4 channel and more |
| AD converter |
20 Bit / 16 Bit |
| Frequency range: |
0 - 20 kHz adjustable |
| Max. Input voltage: |
10mV - 10V adjustable |
| Couppling: |
AC, DC, ICP source(2mA) |
| Anti-Aliasing filter: |
Automaticly tracked |
Scanner software
The control- and analysis sofware has all modules required for a good vibration measurement.
- Video frame grabber
- Measurement point generator / editor
- FFT Analysater
- Laser beam control
- Operating deflection shape analysis
- Animation
- optional Modal analysis
The software works with standard PCs or laptops under Windows XP. It also can be used as an office version without any hardware to do the data analysis in the office.
The results are availabe as time records, spectra, frf's, operating deflection shapes, mode shapes and eigenvalues. They can be exported to several file formats.
The animation modul can generate AVI videos to transfer the animated shapes to third parties. |
Laser Vibrometer