The VibroMet™ 500 SLDV scanning Laser Doppler Vibrometer is a compact, portable, competitively priced, and easy-to-use precision instrument for whole field non-destructive testing and non-contact vibration measurement of any surface. The system uses the patented VibroMet™ 500V engine, together with computer-controlled scanning mirrors and a comprehensive software package to quickly produce vibration maps of any surface. The system is optimized for measuring distances from about half a meter to five meters, so there is no need for adjustments, lens accessories, or object treatment, thus ensuring the highest level of measurement accuracy.

The VibroMet™ 500 SLDV measures the velocity and frequency of vibration at up to 1000 points in the horizontal and vertical direction of a vibrating target spanning an angle of ± 20° in each direction.

There are three parameters that define the measurement requirements:

Distance to target - For good reflecting surfaces, the VibroMet™ 500 SLDV can measure targets at any distance between about 0.5 m and 5 m. If the surface is not a good reflector, then the maximum distance may be less than 5 meters.

Frequency of vibration - The VibroMet™ 500 SLDV can measure frequencies from close to DC to 40 kHz.

Velocity of vibration - This parameter has a maximum value of 0.8 m/s and may be calculated as follows: V = 2 PI * amplitude * frequency. For example, if the amplitude of vibration were 10 microns and the frequency of vibration 1 kHz, then the velocity would be 0.063 m/s.

Components

• Laser head with mirror unit
• Controller box 
• Data acquisition
• Laptop with control and analysis software

The complete system is very compact and is easy to carry, for example when travelling on an airplane.

The laser head includes the laser unit, the mirrors and the video camera. No adjustment of any lenses or the optical system is needed. The position of the laser beam is controlled by the scanning software.

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 the output low pass filter limit the frequency range of the signal.

Acquisition Hardware

The VibroMet SLDV system can be used with any general purpose data acquisition system (such as the HGL Dynamics range of data acquisition products). The minimum requirements for use with the SLDV are as follows:

• 16/24 bit A/D resolution
• 20 kHz Bandwidth
• Input voltage 10 mV - 10 V (adjustable)
• AC/DC coupling

Software

The HGL Dynamics control and analysis software has all of the modules required for good quality vibration measurement:

• Video Frame Grabber
• Measurement point generator / editor
• FFT Analyser
• Laser beam control
• Operating deflection shape analysis
• Animation
• Optional Modal Analysis

The software works with standard PCs or laptops under Windows XP. It can also be used in a 'back office' mode without any hardware to do further data analysis after completion of data acquisition.

The results are available as time records, spectra, FRFs, operating deflection shapes, mode shapes, and eigenvalues. The results can be exported to several file formats.

The Animation module can generate AVI videos to transfer the animated shapes to third parties as required.

Benefits

When working in conjunction with the optional comprehensive software, the VibroMet™ 500 SLDV enables the generation of a flexible measurement grid on the target, automatic scanning of the programmed grid, a large variety of data analysis and filtering options, and 3D animation and visualization of results.

The VibroMet™ 500 SLDV uses a collimated beam and does not require a focusing lens, therefore it is easy to change the target distance anywhere in the range between 0.5 m and 5 meters.

There are actually two lasers in the VibroMet™ 500 SLDV. The laser making the measurement is an infrared 780 nm laser. The second laser is a red 650 nm laser that can be turned on and off by a switch on the back of the laser head. This red laser is used to see where the measurement is being taken. The Infrared laser light has a deep red colour that can readily be seen on most targets.

Options are available to use the VibroMet™ 500 SLDV at frequencies up to 80 kHz.

Specification 

For further information, please refer to our SLDV Frequently Asked Questions or contact:

Pete Oakes at our Lincoln(UK) office

Telephone: +44 1522 692916

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