Inductive sensors make automation a safe investment

The most important
requirements for inductive sensors are precision, maximum availability, and long service life. When the portfolio comprises
of a range of models, enables customer-specific adaptations and solutions for
specific industry applications, and offers Industry 4.0 connectivity, there is
no reason why inductive automation should not be a safe investment.

Over
the past few years, SICK AG in Waldkirch has expanded its sensor knowledge to
the field of inductive proximity sensors. Today, the company offers a broad
product portfolio with product families and models for different ambient
conditions, various sensing ranges, numerous installation scenarios, and a huge
range of connection variants, voltage supplies, and switching outputs as well
as IO-Link. It perfectly complements the broad range of other physical sensors
and operating principles – optoelectronics, capacitance, or ultrasound – to
provide high-performance, high-quality solutions for industry-specific or
individual automation tasks.

Cross-model portfolio for basic
applications

Whenever
non-contact detection of metallic objects is required, inductive sensors are
the ideal choice thanks to their electromagnetic principle of operation.
Furthermore, the non-contact object detection and the absence of moving parts
in the initiators, combined with the special ASIC technology, make inductive
sensors from SICK particularly rugged and durable. This applies to all product families – the IQ rectangular design,
the IH sleeve design, and the IM and IME metric cylinder housing. The sensors
are available with plastic or metal housings in various dimensions including
short and miniature designs, analogue versions
for discontinuous distance detection, versions for flush or non-flush mounting,
and different enclosure ratings including a version resistant to high pressure.
There are also variants available with normally closed or normally open
switching functions, with cable or male connector connection, product families
with an increased sensing range and the Triplex series with triple the sensing
range. Additionally, there are different
electrical versions available including multi-voltage sensors and NAMUR devices
according to EN 60947 with EC type-examination certificates for ATEX areas. This provides the greatest possible degree of
freedom for basic applications.

The
sensors in the IQG product family, for example, are setting new standards for
lightning-fast mounting: With the patented push-lock system, the sensor can be mounted in just two seconds without any
tools. Thanks to the sensor head, which can be
rotated in five different directions, the IQG family can be integrated
into a whole range of mounting scenarios. The four corner LEDs enable
straightforward sensor status monitoring, whatever the mounting position.

They
are available in a short variant for use in factory automation and a long
variant for outdoor applications. In live operation, the IQG proximity sensor
family boasts long sensing ranges, an extensive ambient temperature range,
excellent resistance to shocks and vibrations, plus electromagnetic
compatibility. Even in extremely harsh environments with severe weather
conditions, the sensors operate reliably at all times.

Long-term survival under special
conditions

Standard
applications in industrial environments are
defined by moderate requirements, e.g., IP67, no long-term exposure to
oils or coolants, or ‘normal’ temperature resistance. As the operating and environmental conditions become more demanding, different
performance features are required depending on the industry and application. For
example, enhanced temperature resistance; chemical resistance; tightness;
resistance to shocks, vibrations, and outdoor conditions; or additional
intelligent functions. Previously, these particular requirements often were fulfilled by special sensors
designed specifically for the application in question. Now, however, SICK has
created an ‘all-rounder’ – the IMB
product family – which combines the individual strengths of the ‘specialists’
in one universal sensor.

The
sensors feature a corrosion-resistant stainless steel housing and are available
in models M08 to M30. They cover a range of specifications, including a
temperature range from -40¡C to 100¡C, constant spraying with or immersion in
water, tightening torques up to 100 Nm, resistance to shocks and
vibrations up to 150 g, and permanent contact with aggressive cutting oils
and cooling lubricants. The IMB product family, therefore, meets key requirements for
rugged, inductive sensor technology as used in applications such as container
spreaders, car washes, machine tool construction, or on outdoor gates and
barriers. The universal applicability of the IMB
enables the users (generally machine manufacturers working in these
industries), to significantly reduce the number of product types in use, which
in turn makes all of their procurement, engineering, logistics, and service
processes much more efficient.

From
both technical and financial perspectives, the IMB
is positioned between the various
standard inductive series and the ultra-rugged IMF product family. Like IMB, the IMF devices are also stainless steel
sensors in models M08 to M30, which are suitable for flush and non-flush
installation and working distances between 2mm and 20mm. In line with their
main area of application – machines and plants for food production and
packaging/bottling – IMF sensors in enclosure ratings IP 68 and IP 69K boast
exceptional tightness, which is particularly important due to the frequent
high-pressure cleaning of plants in the food and beverage industry. The
materials used – including stainless steel 1.4404/ AISI 316L and liquid-crystal
polymers (LCP) – are FDA-compliant. Furthermore, the stainless steel of the
Ecolab-certified inductive sensors demonstrates excellent resistance to
chlorine-based media such as hypochlorite-based disinfectants or
chlorine-alkaline foam cleaners. As well as their ruggedness, the IMF sensors
also offer excellent accuracy, short response times, and easy commissioning and
remote diagnostics.

And
when it comes to smart basic functions and inner workings, the IMB and IMF will
not be found wanting either. The special ASIC in the sensors is responsible not
only for the highly precise adjustment of the working distances and the
temperature compensation but also the
option of IO-Link communication. As well as reporting the output state, this
interface can also be used to verify the secure sensing range, perform basic
function diagnostics as part of condition monitoring, and set and
activate/modify parameters such as the switching or counting function.

Inductive operating principle in the world of Industry 4.0

The
IO-Link communication interface bridges the gap to inductive sensors with
special functional intelligence, which is
becoming more and more important against the backdrop of the Smart Factory of
the future and the Internet of Things (IoT).

These
sensors include the IMC product family with metric housings in the models M08
to M30, as well as the IQC series in two rectangular housings. Both sensor
families offer up to four programmable switching points/windows in a single
sensor. Only one IMC or IQC sensor is now
required for the various switching points. The sensors provide more elegant,
space-saving, cost-effective, and easy-to-install solutions for applications,
such as the multi-stage/ infinitely variable detection of gripper positions,
monitoring the open/closed state and wear of industrial brakes, or checking
towing and conveyor chains for straight running, deflection, and wear.
Reducing the number of variants results in further potential savings, which in
turn, makes it possible to program the final output stage flexibly as a normally
open, normally closed, or complementary output. Adjustable switch-on and
switch-off delays help to debounce signals in a decentralised
manner and optimise processes. In the
future, it will also be possible to move more complex tasks – such as time measurements, counting tasks, or the
creation of complex signal chains – directly into the sensor without having to
go via the PLC.

Furthermore,
these inductive sensors offer excellent Industry 4.0 connectivity – for
example, in the form of advanced diagnostic functions, an easy-to-commission
teach-in function, or a self-monitoring sensor function for preventative
maintenance.

These
functions, combined with exceptional performance levels enable the sensors to
perform demanding automation tasks. Examples include distance analyses, profile
monitoring on workpieces, classification, alignment, and singulation of
metallic objects in the material flow, or advanced remote sensor and process
diagnostics via IO-Link.

Their
operating principle may not be new in the world of sensor technology, but there
is no limit to the innovations that can be
achieved with inductive sensors. Whether it is a standard sensor, a
rugged all-rounder, or a smart component, inductive sensors make automation a
safe investment.

Written by Dipl.-Wirt.-Ing. Börge Wegner, Product Manager for Sensors
& Connectivity, SICK AG, Waldkirch and Dipl.-Wirt.-Ing. Michael Stingl,
Sensors & Connectivity, SICK AG, Waldkirch

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