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LASER SCANNER
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APPLICATIONS |
Description
The Scanner RODER Electronics provides the 2-dimensional measuring of profile heights. The
measured objects may consist of various materials. A laser line is projected
onto the target and the distance to several points of the object is measured by
triangulation. The height (Z-axis) by distance (X-axis) is measured. The result
is the 2 dimensional contour of the object.
Typical applications
Precise guidance of handling robots
- Assembly of window panes
- Positioning of car bodies
- Gap adjustment in automotive
- Quality assurance
Measurement for automatic assembly
- Notch
- Gap
- Edge
- Width and depth of fissures
- 3D shapes and profiles
Object detection
- Discrimination
- Go/no-go recognition
- Completeness
- Collision detection
- Mobile gap measurement
Welding
- Seam control
- Automatic welding robot guidance
Method of measurement
The Line scanner RODER Electronics is working according to the triangulation method.
The laser line is produced by a pulsed laser diode and line generating
optics. The diffuse reflected light from the target is projected onto
2-dimensional CCD-Array (Fig.1).
The different contour height of the measured object produces deviation
of the reflected laser line. This deviation is correcyed and linearized
trigonometrically.
In addition to the distance information, the position of the measured point at the laser line of the line scanner is shown.
Scanner construction
The scanner features a very compact construction since all the linearization and
distance measurements are already handled completely from integrated hardware in
the scanner itself. A narrowband filter protects the sensor against external light influence up to
5000 Lux. The optics are protected by an optionally available, replaceable
plastic window. These plastic windows will repell welding plasma sparks. In case
of wear the protection window can be changed quickly. There are no moving parts
in the scanner, which makes it completely free of maintenance.
Data Output
There are several data processing unit of the RODER Electronics Series :
- ISA-PC board
- MEL Blue Box V2 for Ethernet-Interface
- i-Control with integrated PC-104 -RS-232, CAN-Bus, Profibus-DP,
Ethernet
-EPP-parallel-Port, 4 Analog output 0-10V-digital output,
digital input.
Detailed measuring method
The object is scanned by the fanshaped light beam of the laser. For each light
beam, the points on the object are calculated from the scanner.The coordinates
of these points are linearized and then transferred as 2 by 2 values. The real
profile of the surface can be achieved as a representation of Z(X). The
distances of the measurement points on the X-axis are not constant and increase
with the distance to the sensor.
Scanner Configuration
The shutter speed is regulated depending on the brightness of the reflected
signal. The diffuse reflection of the objects surface is influencing the shutter
speed. Surfaces with more diffuse reflections will yield brighter profiles, thus
causing shorter shutter times. Darker surfaces result in longer shutter times
accordingly.
Due to an automatic Gain Control of the Video signal, the shutter speed can be
reduced, hence causing of some extra noise.
Depending on the reflections of the surface, shutter speeds between 1/47.000
sec. and 1/225 sec. are typical.
Safety precautions for Laser
When setting up the Scanner it is important that the Caution sign will be
visible very well. The power of the Laserbeam is so low, that damage to the human eye ist prevented
by the wink reflex of the eyelid. It is harmless to view into the diffuse
reflected laser line
Interfaces
Digital Outputs
The scanner can output the digital profile data via the integrated
Ethernet-Interface. Detailled information about interfaces and software control
can be found in the respective hardware- and software manuals.
Signal Inputs
The following functions can be adjusted via Ethernet -Interface:
- Time of exposure
- Video-Gain
- Trigger-Input
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