Fibre optic sensors: Flexibility, functionality, versatility

Very low
installation space required, flexible use in the smallest of corners,
functionality for standard and complex requirements, and versatile application
possibilities – this are some of the advantages of fibre optic sensors from SICK. Whether as a scanner or a through-beam
light barrier, a large number of fibre optic and end sleeve options provide ideal
automation solutions for nearly any working environment.

Amplifiers with integrated senders and receivers are tailored
for both challenging applications and conditions. The new GLL170 product family
encompasses performance features and technical automation equipment that
provide versatile and economical standard applications. Key features include glass
or plastic fibres, thread, straight or long sleeves, straight or 90¡ angled
light emission, flat design for point detection and area detection with the line-shaped
light spot. They also include highly-flexible fibre optics with small bend
radii, and chemical, oil and heat-resistant sheaths with fibre cores made from
plastic, metal or Teflon. Applications for this
technology include electronics and solar production industries, the
semiconductor industry, packaging machine construction, handling and mounting
systems, the wood processing industry and special mechanical engineering.

Fibres – specialists for special

the installation space at the detection site of a machine is not large enough
even for a miniature sensor, fibre optic
sensors are often the only option for detecting objects. The separation of
optics and evaluation makes it possible to come very close to the detection
object both with scanners and with through-beam systems. When using
highly-flexible fibre optics or variants
with diverted light emission, technical and economical solutions can be
implemented even under unfavourable
installation conditions. High temperatures,
aggressive oils, chemicals or mist, are conditions in which the
appropriate versions of fibre optic
sensors are needed. In both hidden and
invisible mounting, fibre optic sensors
often have the decisive advantage that their amplifiers can be installed at easily-accessible places. This means the sensor is accessible and
operable at all times.

addition to the user-friendly application during commissioning and practical use, fibre optic sensors cover the entire range of performance features
thanks to their amplifiers. The application determines the use of potentiometer
or teach-in setting and the switching frequency, depending on the given object
speed or desired detection speed. Operating modes such as a release delay and
switching outputs are available, as are versatile connectivity options.
Fieldbus connections have the advantage
of offering complete access to all parameters of the fibre optic sensors from the control. That means settings do not
have to be made directly on the device – and information can be inputted
directly to the automation system. Fibre optic sensors thereby also offer
unrestricted solutions for automation technology
and prove themselves to be specialists.

New GLL170T amplifier: PNP and NPN
output types in one sensor

new GLL170 fibre optic amplifier is even
easier to operate and offers a higher level of flexibility. With both the
GLL170 with a potentiometer and the
GLL170T teach-in version with digital display, the user can flexibly adjust the
sensor parameters to the application. Both amplifier versions fulfil the requirements of enclosure rating
IP66 even without a rear cover. This
means they can be installed directly on the machine using either mounting rail
supports or fixing holes in the housing. The teach-in version features both PNP
and NPN output types in one sensor, making it suitable for machines in European
and overseas markets. Also, its
alpha-numeric display simplifies the monitoring of the process parameters.
Together, the market-tested WLL180 amplifier for challenging applications and
the GLL170 product family for versatility
covers nearly all the requirements for automation technology.

Semiconductor, electronics and
solar: Fibres detect with line-shaped light spot

optic sensors have applications for the semiconductor, electronics and solar
industry through compact machines and transport modules. Sensors are used to
check the positioning of wafers, monitor the height of wafer stacks, and detect
lead frames or substrate carriers in hot wire bonding environments and to
capture the leading edge of printed circuit boards. Since these are often thin or flat edge objects, scanners or through-beam
systems with an array-type light emission are often used. During
processing, the challenge is to reliably detect printed circuit boards that are
only 0.2 millimetre thick, and sometimes
with curved or bent leading edges. The task is
completed with a new GLL170T amplifier and LL3-TS05 fibre optics with array optics. The sensor
projects a light beam in the area through which the printed circuit board is transported. In contrast to point detection,
the task is done here with a line-shaped light spot. This ensures that the leading edge of the printed circuit board is reliably detected in any position within an array of about five millimetres.

Packaging technology: High process
reliability at high speeds

machine engineering company for the tissue and hygiene industry manufactures
tissue machines with integrated single and container packers, which can produce
almost 5,000 tissues per minute. The reliability of the sensors at such high
speeds and production quantities is extremely important. After smoothing and
pressing the tissues (up to four layers in height), the compressed sheet of
tissues goes through the cutting, folding, and stacking module of the machine where
it is slit, folded, and fed to a stacking magazine, from which it is then transported to the packaging module in
piles. The machine manufacturer created a shaft and congestion monitoring point
on the stacking unit with a WLL180T fibre optic amplifier. This sensor is ideal
due to its compact size, fast response times of just 16 µs, and high light
intensity and resolution, ensuring an additional operating reserve in this dusty
operating environment.

Timber industry: Fibre optics
withstand dust and shavings

safe, and efficient production processes are indispensable for high
productivity in the sawmill, wood
material, veneer, and furniture industries. Dust and particularly shavings,
make wood-processing machines a challenge for optoelectronic
sensors in general. Fibre optic sensors, which are used to position trunks in
front of saws or slats in front of stacks, can
withstand disturbance variables for reliable object detection. A through-beam
system with a metal M12 threaded sleeve and an optical lens integrated in the fibre optic head for strong focusing of
the light beam and a fibre optic amplifier with high transmitting power, provide
the mechanical and optical ruggedness needed for this environment. The special
beam array and, if necessary, the setting of a switch-off delay ensure that
foreign bodies in the light path do not result in false switching signals.

optics made of plastic or glass fibres with amplifiers for different automation
requirements are the basis for fibre optic sensors enabling a wide range of
application-specific solutions with high reliability and availability.

Written by Kai Huber, Product Manager for Fibre optic Sensors, SICK AG,

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