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Inductive sensors make automation a safe investment

Supplier: SICK Pty Ltd By: Dipl.-Wirt.-Ing. Börge Wegner, Product Manager for Sensors & Connectivity, SICK AG, Waldkirch. Dipl.-Wirt.-Ing. Michael Stingl, Sensors & Connectivity, SICK AG, Waldkirch
16 April, 2018

Over the past few years, SICK AG in Waldkirch has expanded its sensor knowledge to the field of inductive proximity sensors.

The most important requirements for inductive sensors are precision, maximum availability, and long service life. When the portfolio comprises 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, analog 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 a technical and a financial perspective, the IMB is positioned between the various standard inductive series and the ultra-rugged IMF product family. Like the 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 2 mm and 20 mm. 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 & 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, the 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.