Components of the LDV system
The main components of the Polytec Scanning Laser Doppler Vibrometer are the scan heads (top, left and right), Vibrometer controllers (OFV-5000) for each scan head, junction box connecting all these controllers and a personal computer (PC) containing the PSV software.
PSV-I-400 Scan head
Each scanning head has four major inbuilt units. They are video, scan electronics, scanning mirrors and photo sensor (OFV-505) units as shown in the Figure 36.3.
Figure 36.3 Scan head and its inbuilt units.
Salient features of the scanning head are
- Scan angle ± 20o with 0.02o resolution
- 72 x Zoom video camera
- Large working distances 0.5 m to 50 m
- Close up unit for scanning small objects in millimeter range
- Laser focus, alignment procedures can be remote controlled using PDA which connects directly to the PSV software
Vibrometer Controller (OFV-5000)
The Vibrometer controller provides signals and power for the sensor head which is present in the scan head and processes the vibration signals. They are electronically converted by specially developed analog and digital decoders within the controller to obtain velocity and displacement information about the test structure. Information provided by controller is available in analog or digital form for further evaluation of data. The analog output is provided at standard BNC connectors.
Junction Box
The junction box acts as an interface between the Vibrometer controller and the PSV software. Vibrometer controller of each scan head is connected to the junction box. Input for up to 8 analog signals and trigger are available on BNC connectors. |
