MEL M70LL 0.5, Manual

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Manual M7LL / M70LL Laser ‐ Sensors
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HB ‐ M7LL ‐ M70LL ‐ E.doc page 6 of 23 V20130301
MEL Mikroelektronik GmbH, Breslauer Str. 2, 85386 Eching / Germany www.MELSensor.com
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Objektoberfläche
Drehachse
Drehachse
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30°
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A thickness measurement system is made of two sensor systems
with an add ‐ on option thickness measurement. The sensors are
directed on the upper and lower surface of the object. The slave
sensor (usually at bottom) sends his distance signal to the master
sensor. The master outputs the thickness value which is the sum of
both sensor signals.
A thickness measurement system is made of two sensor systems
with an add ‐ on option thickness measurement. The sensors are
directed on the upper and lower surface of the object. The slave
sensor (usually at bottom) sends his distance signal to the master
sensor. The master outputs the thickness value which is the sum of
both sensor signals.
The output voltage of the thickness signal is 0…10V for the range of
both sensors.
The output voltage of the thickness signal is 0…10V for the range of
both sensors.
Each sensor head has its own electronic system (blue box). Each sensor head has its own electronic system (blue box).
Measurement errors Measurement errors
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Objects could be various materials like metal, plastic, ceramics,
rubber and paper. With highly reflective materials or liquids it should be tested for the individual material if the M7LL could measure
this surface.
Objects could be various materials like metal, plastic, ceramics,
rubber and paper. With highly reflective materials or liquids it should be tested for the individual material if the M7LL could measure
this surface.
On partially transparent plastic or bleary liquids the laser beam penetrates into the “material surface” before the diffuse reflected
light is sent back from the surface. The real measured distance needs to be corrected by a factor of “penetration depth”.
On partially transparent plastic or bleary liquids the laser beam penetrates into the “material surface” before the diffuse reflected
light is sent back from the surface. The real measured distance needs to be corrected by a factor of “penetration depth”.
Scratches in the measurement spot Scratches in the measurement spot
A scratch across the lens axis may cause stronger reflections, with a maximum of energy at the side of the spot. This will affect the
distance information. In the same time the intensity value will change. For testing on scratches this method may be more helpful
than monitoring the pure distance information.
A scratch across the lens axis may cause stronger reflections, with a maximum of energy at the side of the spot. This will affect the
distance information. In the same time the intensity value will change. For testing on scratches this method may be more helpful
than monitoring the pure distance information.
When the object is moving, the average (integrated) value will be constant when moving over the scratch. This means: the positive
and negative edge of the signal will compensate each other.
When the object is moving, the average (integrated) value will be constant when moving over the scratch. This means: the positive
and negative edge of the signal will compensate each other.
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When highly reflective objects are close to the measurement spot, mirroring the laser light into the receiver optics, then
measurement errors may be caused.
When highly reflective objects are close to the measurement spot, mirroring the laser light into the receiver optics, then
measurement errors may be caused.
Objects with diffuse reflectivity may not cause the same errors. When the mirroring surface is outside of range, the residual error
may be up to 2%. Due to the smaller spot size, stray light error is smaller for Laser sensors than for LED sensors.
Objects with diffuse reflectivity may not cause the same errors. When the mirroring surface is outside of range, the residual error
may be up to 2%. Due to the smaller spot size, stray light error is smaller for Laser sensors than for LED sensors.
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When distance measurement is made in a place where the
material surface is changing from diffuse reflecting to mirroring
material and therefore the reflectivity is changing strongly,
during the transit measurement errors may occur. The
maximum of the intensity is not in the center of the spot.
When distance measurement is made in a place where the
material surface is changing from diffuse reflecting to mirroring
material and therefore the reflectivity is changing strongly,
during the transit measurement errors may occur. The
maximum of the intensity is not in the center of the spot.
In direction A, the error is minimal; in direction B it is maximal. In direction A, the error is minimal; in direction B it is maximal.
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The sensors are equipped with a automatic intensity regulation
for matching to more or less reflecting objects. When the
surface is changing during measurement, the intensity is kept
constant by the regulation system.
The sensors are equipped with a automatic intensity regulation
for matching to more or less reflecting objects. When the
surface is changing during measurement, the intensity is kept
constant by the regulation system.
A A n n g g u u l l a a r r d d e e p p e e n n d d e e n n c c y y A
The measurement has a small dependency from inclination
angle. Rotation on axis A up to 30° and rotation on axis B up to
15° do not cause big measurement error. Measurements on a surface with good diffuse reflection are less depending on angle than
measurements on mirroring surfaces. (See the picture above).
The measurement has a small dependency from inclination
angle. Rotation on axis A up to 30° and rotation on axis B up to
15° do not cause big measurement error. Measurements on a surface with good diffuse reflection are less depending on angle than
measurements on mirroring surfaces. (See the picture above).
The measurement error shows up as a change in the ratio of output voltage / distance. When the error is constant, a special
calibration could eliminate the error.
The measurement error shows up as a change in the ratio of output voltage / distance. When the error is constant, a special
calibration could eliminate the error.
h h i i c c k k n n e e s s s s m m e e a a s s u u r r e e m m e e n n t t
Dickenmessung
Auch an transparenten
Stoffen
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