With the advent of Industry 4.0, the information age for industry is just getting off the ground, but it would not be possible without intelligent sensors. By Christoph Müller.

The limitless exchange of manufacturing, product, and logistics data means it is now possible to make better decisions and experience complete transparency across the value chain. At the start of the process chain, this world of greater resource efficiency depends largely on the equipment that supplies this data: intelligent sensors. It is absolutely essential for sensor technology to be intelligent, rugged and reliable when it comes to dealing with challenges such as safe interaction between people and machines, high levels of variance, and fluctuating demand at short notice.

Sensors provide the senses for machines. The feedback they provide is what makes intelligent machines possible. Sensor intelligence focuses on one aspect of sensor technology: equipping machines with the ability to see, recognise and communicate intelligently. Intelligent sensors contribute the ability to classify and interpret information. This is characterised by intelligent signal processing, which derives the truly relevant information from large quantities of data and makes it available. Therefore, in addition to primary control system for machines and systems, information is provided for monitoring production systems and making it possible to detect faults. Transparency of processes and material flows produces additional potential for optimisation. Processes are becoming more efficient and cost-effective, increasing competitiveness.

Flexible automation

Using a packaging machine as an example shows how an automatic batch change without manual intervention by using intelligent components with automated control generates higher product diversity with a general increase in productivity. Maximum productivity with product variation down to a batch size of one is a central goal of the Industry 4.0 concept. Manufacturing plants must be flexible and adapt to what the individual customer wants. Due to high product diversity even as the part batch sizes continue to decrease, intelligent components (smart sensors) must be capable of adjusting and controlling themselves.

One example is a final packaging line capable of handling bottle sizes of 0.5 litres and 1.5 litres on one system through detection from smart sensors with automatic format changeover. The sensors detect the product changeover and tell the control system to readjust so the right box can be set up, the bottles can be fed in, and the box can be labelled and transported away. The changeover steps are listed on a monitor while the machine adjusts. The system keeps running automatically and does not have to be put back into operation manually. If the sensors detect an incorrect placement when measuring the length of the product, they notify the control system. The product is sorted out without the system coming to a stop. In addition, sensors provide data for pro-active maintenance, such as monitoring for fine particles to automatically implement safeguards.

Intelligent, communicative sensors are what make Industry 4.0 possible in the first place. Smart sensor solutions – the use of state-of-the-art sensor technologies in combination with complete integration into the control level – focuses heavily on decentralising certain automation functions to the sensor. This takes some of the load off of the control system and increases the productivity of machines.


Sensor intelligence is a prerequisite for safe interaction between people and machines in the era of Industry 4.0. Safe laser scanners reliably monitor the hazardous area around stationary or mobile machines and systems, such as welding robots or automated guided systems. Protection of people is the top priority. If a person enters the area, the dangerous movement must be stopped safely. On established systems, people are protected but production is stopped.

In the future, in the context of Industry 4.0, smart sensors will be used not only to ensure the safety of people, but also to implement ever-increasing production specifications. Today SICK is already providing up to four simultaneous protective fields, thereby considerably increasing the ergonomics and efficiency of complex machines such as tire heating presses. The digitally switching protective fields currently in use are being replaced with flexible ones.

Flexible protective fields are automatically calculated during highly dynamic movements and adjusted corresponding to the hazardous areas of the robot. Commissioning is also made considerably simpler and faster thanks to smart sensors. The optimum interaction of smart sensors and state-of-the-art machine designs increases the productivity of the machine and always guarantees the safety of the employees. The compact systems use an integrated swivel mirror as an optical radar to scan their surroundings in two dimensions and measure distances according to the time-of-flight measurement principle. This results in freely definable safety zones.

Track and trace

In the automotive industry, comprehensive data acquisition makes it possible to identify a customised dream car throughout the entire production process up until delivery. Using this track-and-trace process, it becomes clear how increasing product customisation can be implemented in the context of Industry 4.0. Right at the car body, sensors detect which assembly steps have to be introduced, making mix-ups impossible. As a result, they ensure comprehensive transparency up until delivery.

Processing steps on the object are updated by rewritable RFID tags. Reading reliability is a necessity because any read errors could cause misdirection, mix-ups or production downtime. This is where RFID data cards – which can be attached to components or even integrated out of sight within them – are coming into play more and more. In practice, they have the highest possible availability. For example, they are capable of withstanding high temperatures on a painting line and can be reliably identified even once covered in paint.

Aspects such as transparency and traceability are playing an ever more important role for manufacturers, because the variability in the production lines of large automobile plants is constantly increasing and assembly lines are seeing more and more variants being built in parallel.

Vertical integration is the key for track and trace. Traceability of products during complex manufacturing and logistics processes is a priority for this integration. Production and logistics require transparent material flows so that production decisions can be made faster.

Transparency of the material flow based on RFID also plays a critical role in delivery. Until the completed cars are ready to be picked up and transported to the dealership, they are kept in a large parking lot. But how do you find the car that still needs to go on the truck? Every single car is made to order; no two are alike. Thanks to the information stored on an RFID tag, the customer’s dream car is located quickly and can be loaded up for transport in no time.

Quality control

The future holds continued increases in the speed at which packages are transported. The distances between the packages are becoming smaller. This means checking the quality of products is even more important.

To accomplish this, the package data is scanned on the conveyor belt and read into the software. The packages are identified and compared. Is the package damaged? Is the code complete? Are the weight and volume the same? Is there a pileup of packages, or is a package possibly even missing?

Automatic fault detection is made possible by comprehensive product and production data. The data is completely synchronised in seconds. Defects can be tracked by all centres, and it is possible to trace where the weak point is. In addition, quality defects can be identified and resolved in the process. Since the speeds on the conveyor belts are further increased, maximum productivity is ensured – not just within a location, but also globally.

This example of an intralogistics process shows how increasing quality requirements and the desire for resource efficiency can be implemented in the context of Industry 4.0. The sensors detect changes to the object and enable seamless data acquisition. The software solution analyses the process data and implements actions. The combination of a variety of data and the analysis software is an important prerequisite for Industry 4.0 and the issue of sustainability. Goods in the production process and the supply chain must be reliably and uniquely identified so that these can support efficient automated control. From an individual package on a conveyor belt to a complete overview of millions of packages transported every day—there must be a convenient way to call up and analyse the status of all acquired data.

Smart sensors acquire and communicate this data. However, users do not experience true added value until this data can be used as a basis for improving business processes. This data offers extensive opportunities but also presents the significant challenge of preparing it in a way that allows companies to make the right decisions. This is the cornerstone of Industry 4.0: the seamless flow of data and information from the sensor to the control system and back.

From sensor to sensor intelligence

SICK has always developed and built intelligent sensors. The fact that the company has been on the scene for 10 years with a focus on sensor intelligence underscores the consistent further development of the corporate strategy. This is embodied in the literal meaning of the term sensor intelligence.

Further development of intelligent sensors does not mean that the future and past are independent of each other. Rather, they form an inseparable unit of technological developments that build upon each other. Starting in the 1950s, SICK’s founder, Dr Erwin Sick, used his vision to create intelligent solutions for safeguarding machines and monitoring emissions. Before long, advances in electronics allowed for miniaturisation of the devices and provided the essential driving force behind technology in automation engineering.

The triumph of microelectronics continues even today. An example of this is seen in the powerful ASICs, which SICK developed and uses in devices such as optical and inductive sensors. The increasing speed in the computing power of state-of-the-art chips enables remote processing of substantially larger amounts of data and capabilities like the associated use of complex mathematical methods. This is resulting in completely new dimensions for the scope, accuracy and ruggedness of measurements. Sensor solutions measuring in multiple dimensions, such as camera systems and laser scanners, would also be impossible without this development due to their high data volume.

Computing power enables even more intelligent sensors, but they do not turn into sensor intelligence until equipped with the right software and application knowledge. The intelligent linking of application knowledge, with the flexibility of state-of-the-art software architectures, enables the next development stage for sensors. This is characterised by the possibility of sensors that can perform more extensive analysis, automatically adapt to changes, communicate in the network and remotely solve complex tasks within a larger manufacturing network. In other words, the sensor links to the machine, system, factory, and the entire value-creation chain and provides for transparency in production. As a result, it provides the entry point into the world of Industry 4.0.

For all virtual worlds, however, sensor intelligence remains one thing above all – part of a sensor. Even the cloud and apps need to have a physical basis in the real industrial environment, namely, a rugged and reliable piece of hardware. And building this hardware requires one thing above all: decades of experience.

Christoph Müller is Manager – Global Marketing & Communication at SICK.