Intelligent photoelectric sensors: Safe detection, efficient automation

Efficient automation
is always also a question of safe object detection. Photoelectric sensors that
offer optimum detection performance are designed specifically for their area of
application, meet high technology and quality standards, and support
intelligent automation functions are proving their worth as reliable and
cost-effective solutions that are worth investing in for a wide and challenging
range of applications.

most cases, the primary aim of object detection is to maximise the productivity of machines, systems, and processes. The
clear demand for maximum performance is matched
by the versatility of the requirements set by the vast scope of object
properties, ambient conditions, installation situations, or automation and
communication preferences. As a global technology and market leader for optoelectronic sensors, SICK offers by far the
most comprehensive portfolio of photoelectric sensors on the market – and can
thus rise to meet virtually any challenge across the industry and indeed the

Reliable not random: Detecting all
manner of different objects

wide portfolio enables it to make a promise to find a solution every time. Suitable
photoelectric sensors with the widest possible range of characteristics are
available for object detection. The optical appearance of objects can be dark,
patterned, transparent, or shiny. Perforated or uneven object surfaces are also
a factor in the selection of sensors, as is the distance of the objects at
close and long range, or their detection through gaps and openings. High-speed
processes require a ‘rapid eye’; and certain object shapes (contact pins on
semiconductor components, for example) call for a special ‘sharp eye’.
Regardless of whether an individual object property is to be considered in isolation or some features are to be considered together,
SICK’s portfolio of photoelectric sensors will be able to provide at least one
suitable solution for virtually any application. This is made possible by SICK’s SIRICoptoelectronic ASIC technology. Photoelectric
sensors with SIRICoffer maximum optical durability to LED
illumination, ambient light, and emitted light from other sensors, as well as
supporting both extended sensing and scanning distances and enhanced operating
reserves. SIRICphotoelectric proximity sensors also impress with
the best background suppression in this sensor class. The highly integrated
chip technology makes it possible to reduce the size of the components without
impairing detection performance. By applying the auto-collimation principle,
the photoelectric sensors can be relied upon to detect objects even through
small gaps and openings, and avoid blind zones at close range.

Sensor equipment: A great deal of standard and many additional options

SIRICprovides the basis for the standard design and dimensioning of the optics
and electronics of the photoelectric sensors. Users can choose light sources in
the form of infrared transmitters for detection tasks with high sensing
distances, PinPoint and laser LEDs, e.g., for small objects and high-speed
processes, or blue light for the detection of materials that absorb light
(solar wafers, for example). The shape of the object determines the shape of
the light spot on the object: dot, line, double line, or light beam is
possible. Photoelectric proximity sensors also differentiate between standard and
V optics and can even be used to scan flat, transparent objects such as smartphone
displays. SICK’s ClearSens technology can be relied upon to detect transparent
objects, and sensors with AutoAdapt functionality can track the switching
threshold automatically, thereby significantly extending the maintenance-free
availability time of the sensors.

the wide variety of sensors that are available as standard not be sufficient,
the platform of SICK photoelectric sensors can be customised to meet technical and budgetary requirements – even at
short notice, if this is dictated by requirements. Within the SICK organisation, a clearly
defined process is followed, from application analysis through to series
delivery. Light sources and detection principles can be adapted to suit the
material, optical appearance, surface, and shape of the object(s) to be
detected. The operating software can be customised
or even programmed based on an
application. System default settings can be adapted to meet specific electrical
integration requirements. The connectivity and the pin assignment of the electrical
interfaces are also open for special solutions. For both standard and special
devices alike, a suitable sensor solution is almost always available immediately in
stock or can be produced quickly.

Best performance: A proprietary
standard in any setting

the quality and performance of photoelectric sensors are concerned, SICK
measures itself not against the market standard but by its own specifications,
which are much more demanding. To a significant extent, these specifications
are the result of seven decades of experience and knowledge of the requirements
to be met by sensors in daily practice. SICK has developed its own test processes as it strives to meet
expectations in product creation. These processes are used to simulate
physical, chemical, photo biological, and climatic factors, for example, or to
measure electromagnetic durability. The internal test guidelines and standards
for all such tests set the bar significantly higher than legal minimum
requirements and market standards. As such, the sensors can rise to any
challenge; even in the most adverse application conditions, they can be relied
upon for maximum availability both in and for machines and systems. In ambient
light, direct sunlight, mirroring, and reflective conditions, SICK optical
sensors retain a clear view – even if dust, window,
and moisture are to be contended with. Almost without exception, the sensors are
temperature-resistant from -40¡C to +60¡C. The sensors are setting new
standards for shock and vibration resistance, and EMC values are significantly
above minimum legal requirements: they are based on the strictest international
standards (IEC 61000-6-2, for example). Compliance is also assured with the requirements of general standards
including those governing EC conformity, Underwriters Laboratories (UL) safety
requirements, or the safety requirements of EU Directive
2011/65/EU on the restriction of the use of certain hazardous substances in
electrical and electronic equipment. For sensors
that are used in the injection area of production and packaging
systems in food processing, beverage filling, or the manufacture of
pharmaceutical products in accordance with the specifications of EN 1672-5.3.2,
SICK also takes its lead from the recommendations of the European Hygienic
Engineering & Design Group (EHEDG) and the specifications of EN 1935/2011,
as befits good manufacturing practice.

Models optimise the distribution of
space in a mounting location

Large working clearances,
detection from near distance, compact machine designs, restricted mounting
space, mobile machine structures, restricted accessibility once installed – there are many factors that affect the ideal
model and size of optoelectronic sensors.
So it’s good to know that SICK’s sensor portfolio can meet these selection criteria to the fullest possible extent.
The photoelectric sensors are available in a wide range of different housings –
made from metal or plastic, from miniature to ‘roomy’, cylindrical, cuboid, or
as fibres, in slim and flat versions,
with M3 threaded female connectors through to M4 longitudinal holes. If it is likely to contact
with aggressive products or cleaning agents, sensors made from stainless steel,
from highly resistance VISTAL glass-fibre-reinforced
plastic, or with Teflon coating, for example, are ideal. Optional accessories
including universal clamping systems, mounting brackets, clamping and alignment
brackets, and protective devices extend the options for optimum distribution of
space. The same applies to the scope of
the electrical connectivity. Extending from the
3-wire cable through rotating male cable connectors and beyond to 4-pin male
cable connectors, it too is extended by additional special options. With
all of this in place, nothing stands in the way of optimum mounting and electro-technical integration. The portfolio
also makes particular allowance for the operational capability of the sensors
once they have been installed; with
teach-in knob, potentiometer, or light/dark switch on the device, external
teach-in via the control cable, or remote configuration via IO-Link, all
standard operating scenarios are catered for.

Photoelectric sensors as smart automation providers

opto-sensors do much more than just
supplying a switching signal – they support various automation functions
directly in the sensor and can be integrated
into modern automation networks with the assistance of the global communication
standard IO-Link. The shifting of what were control functions to photoelectric
sensors and their distribution in a network have
a direct effect on machine productivity and the efficiency of processes. The
option of flexible sensor adjustment via the automation system is of particular
benefit for machines which frequently switch between formats, configurations,
or product variants. Machines and systems in the packaging industry find this
feature especially useful, as the ability to download parameters directly from
a control system to any number of sensors simultaneously saves time, prevents
errors, and can be documented at any
point. High-speed meters are ideal tools in systems that require reliable and
convenient metering or speed/velocity measurement. Time measurement is another
function that IO-Link can be used to implement. This function optimises processes whose aim is to use
accurate time recording to determine
lengths, control numbers of cycles, separate objects, or carry out efficient
slip control. Remote de-bouncing also proves useful in applications that
involve large numbers of interference signals for reasons related to processes
or the environment (in systems used in the woodworking
industry, for example).

Variance means versatility

A variety of housing formats and
materials, different detection principles and optical technologies, as well as
versatile mounting, connection, and operating options,
characterise the significant variance of SICK’s photoelectric sensor
portfolio. The standard sensors, along with the special versions based on them,
offer integrators and users alike countless possibilities for detecting objects
of all types. The detection reliability, durability, and availability are
aligned with the actual requirements of practical applications and often go way
beyond market standards. The option to integrate opto-sensors equipped with automation engineering intelligence into
networks that are not dependent on controllers or fieldbuses maximises
availability and process efficiency, while at the same time delivering future-proof

By Wilhelm Schürmann, Business Unit Manager for Photoelectric Sensors and
Fibers, SICK AG, Waldkirch

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