24 May 2024

Smart sensors – the ‘all-seeing eyes’

David Hannaby, SICK’s UK product manager for Presence Detection takes a look at why sensors are the building blocks of Industry 4.0.

Sensors are the essential building blocks of Industry 4.0. They are the ‘all-seeing eyes’ of the Smart Factory; the data-gatherers that give machines the information they need to operate.

Today’s automated manufacturing and logistics environments with flexible, high-throughput production, rapid product changeovers and high levels of customer-led product customisation would be unachievable and uneconomic without a myriad of sensors to optimise productivity.

Simple tasks like detection, positioning, counting, measurement, timing and barcode reading are just as mission-critical as 2D and 3D vision inspection, level and flow sensors, safety laser scanners or light curtains.

To meet these needs, smart sensors are being developed all the time to suit differing applications, the result of close collaboration between global manufacturers and their customers. Relentless product development is solving customer challenges all over the world in industries as diverse as automotive, to packaging, pharmaceuticals to food, mining to metalworking.

Industry 4.0 Revolution or Evolution?

UK industry still has some way to go to fully embrace all the opportunities that digital connectivity will bring. However, as practical people, engineers want to know what Industry 4.0 means to them on a day-to-day basis.

Industry 4.0 will not come flat-packed in a box and delivered to site. It will be an evolution rather than a revolution and engineers, production and logistics teams will all need to all understand and build up their capabilities one step at a time.

For any production environment, the first priority will always be optimum reliability with minimum downtime. At the same time, engineers need sensors that are quick to install and easy to teach, without needing specialist skills to program or commission. Once installed, they are easily adjusted to suit changes in production and able to be easily replaced, when needed.

A wealth of data

Sensors collect a wealth of data, but until recently, the ability to exploit all that wealth to the full has been limited by the data being ‘trapped’ at a local processing or field level. Now, Industry 4.0 is releasing that data and developing new and better ways for industry to make use of it.

If sensors already had eyes, Industry 4.0 has given them a voice and the ability to hear – in the form of the IO-Link communications gateway.

Meanwhile, advances in chip technology have enabled advanced intelligence to be embedded in the sensors themselves to make them smarter. Far from being the “dumb switches” of the past, their in-built functions, fully-connected via IO-Link, enable more complex production tasks to be performed at the field level.

Smart Sensors therefore take processing load away from the central control system to the sensor itself. Smart tasks are processed locally in real time without the need for the raw data to be uploaded to the central PLC program, processed and then acted upon. The smart sensor reduces the raw data processing burden on machine controllers which can otherwise cause bottlenecks and slow data transmission through a typical centralised control hierarchy.

Five building blocks of smarter sensing

1. Reliability and availability

Tight margins make production downtime the enemy of any manufacturing environment. Difficult-to-see objects, uneven shapes, transparent, semi-transparent, or highly-reflective objects like glass, plastics, films and foils can present reliability challenges. Global manufacturers like SICK have responded with photoelectric sensors that can simply detect any object, in virtually any industrial automation application and in spite of environmental challenges such as dust, or poor light.

2. Flexibility

Much of modern FMCG manufacturing is driven by batch production. Altering machinery settings and sensor parameters manually every time there is a product changeover creates downtime and production stoppages. Intelligent sensors such as code readers and vision systems can detect product changes on the line and trigger a change to new parameter settings automatically with little or no interruption. More rapid and frequent production changeovers help manufacturers meet customer demands for product diversity, local or custom orders.

3. Product tracking and traceability While manufacturers make every effort to ensure product quality, a recall can never be completely ruled out. Strict regulations govern traceability across all stages of production, processing and packaging and there’s mounting pressure to make recalls in ever-decreasing timeframes. With data collected by RFID tags, vision systems and barcode readers, Industry 4.0-enabled organisations can respond rapidly and retrieve vital data in real time.

4. Reduced inventory and easy replacement

There are always times when sensors need to be replaced and manufacturers are responding by making it as quick and easy as possible to install, commission or substitute a device. Perhaps one of the greatest advantages to production teams in Industry 4.0 is the ease with which sensor settings and parameters can be downloaded from a PLC to a new sensor for rapid replacement and commissioning. At the same time, smart sensing technologies can reduce the number and type of sensors needed to be kept in stores, lowering inventory costs.

5. Diagnostics & condition monitoring

In Industry 4.0, the control system is fully connected to “see” the sensor as a distinct and locatable entity, so production processes are given access to a full range of diagnostic capabilities. Is the sensor about to reach the end of its life? Does it need cleaning? Will it last until the next production changeover?Through the combination of sensor self-monitoring and the ability to notify the control system precisely which sensor needs replacing, production teams have much greater flexibility in monitoring their processes. Pre-failure notifications can prevent failures before they happen and sensor diagnostics can be integrated into flexible, needs-based maintenance plans.

A sensor-eye view of Industry 4.0

Industry 4.0 enables machines to gather and use data in real time to deliver greater flexibility in production. The view of the Smart Factory seen through the eyes of sensors makes this particularly clear.

Everyday automation challenges centre on maintaining seamless availability, reliability and high performance at ever greater throughput speeds, while accommodating increasing product variation and customisation. Engineers must manage all this while achieving greater data sharing and connectivity between machines and across departmental and company boundaries.

Without sensors’ fundamental ability to monitor processes and collect reliable, high-quality data in the first place, the Smart Factory would just not exist.

Smart sensors

Manufacturers are developing and discovering new smart sensor applications all the time. SICK has a fast-track programme to add new intelligent functionality and build-in IO-Link capability across all sensor types.

Smart sensor functions include:

• Fault compensation for stable and reliable sensor signals.

• Advanced diagnostics and monitoring through individually-identified devices.

• Predefined detection modes for fast commissioning.

• Advanced adjustments for reliable detection.

• Manual adjustment of the detection parameters for individual application solutions.

• Auto adjustment of switching thresholds as a signal degrades over time until an alarm threshold is reached.

• Active sensor installation and alignment assistance.