Choosing the Right Industrial Sensors for a Product

Industrial sensors play a crucial role within industrial settings, converting physical parameters into signals that can be used for a wide range of applications. So, how can the designer make sure that the right industrial sensor is chosen for a product?

Industrial sensors are devices used to monitor, measure, and detect changes in environmental or operational conditions within industrial settings. These sensors convert physical variables such as temperature, pressure, vibration, proximity, light, humidity, or chemical properties into signals that can be measured, analyzed, or monitored by a system or controller. The data collected by these sensors are essential for automating processes, improving safety, and enhancing efficiency across various industries such as manufacturing, energy, automotive, aerospace, and more.

Figure 1: An optical sensor installed on a line conveyor in a factory. (Image source: Adobe Stock)

The key role of industrial sensors

The key role that industrial sensors play cannot be understated, these devices are vital to enabling automation, safety, quality control measures, and beyond within industrial settings.

Industrial sensors are integral to automating processes, allowing machines and systems to operate with minimal human intervention. They help ensure precision and consistency in operations like assembly lines, robotic systems, and packaging processes.

By monitoring equipment conditions such as vibration, temperature, or pressure, sensors can provide early warning signs of potential equipment failure, enabling predictive maintenance and reducing unplanned downtime.

Sensors can also ensure that manufacturing processes meet the required standards by monitoring variables such as temperature, pressure, and dimensional accuracy. For example, optical sensors might measure product dimensions to ensure quality consistency.

In hazardous environments, these features can be key in the detection of unsafe conditions, such as gas leaks or excess heat, and trigger alarms or safety mechanisms to prevent accidents.

Meanwhile, by monitoring factors like temperature, energy usage, or fluid levels, sensors can help optimize processes, reducing waste and energy consumption.

Additionally, industrial sensors can enable the real-time monitoring of a wide array of industrial processes, feeding data into control systems for timely adjustments and optimizations, helping ensure smooth and efficient operations.

Figure 2: A vibration sensor utilzing magnetics for detection. (Image source: Adobe Stock)

The pain of finding the right industrial sensor for a product

With such a wide range of industrial sensors to choose from, selecting the right industrial sensors for a product can often prove to be a complex task.

One of the primary difficulties is obtaining clear, comprehensive documentation for industrial sensors. Different manufacturers can often provide varying levels of detail, making it difficult to compare specifications directly. Documentation can sometimes be overly technical or lack practical information as well, making it hard to understand how the sensor integrates with existing systems or operates in specific conditions. Additionally, in some cases, product documentation may not be updated to reflect newer models or firmware updates, or it may be difficult to find on the manufacturer’s website.

The diversity of communication protocols in industrial environments also often presents another pain point when choosing sensors. Industrial environments may rely on a variety of protocols such as Modbus, PROFINET, EtherNet/IP, or others. Some sensors may not support certain protocols, creating a mismatch with the existing control systems or requiring costly and time-consuming modifications. There’s also the problem of interoperability to contend with, ensuring that the selected sensor can communicate effectively with existing hardware and software is critical. In some cases, additional hardware (like gateways or converters) might be required to make the sensor compatible with the system, further complicating integration.

Integrating with IO-Link is another of these problem points, given that the communication standard is relatively new for sensors and actuators. While it offers significant benefits, its adoption can come with some challenges. A steep learning curve, limited availability of knowledge resources, and its integration into legacy systems are just to name a few.

Finally, there’s always the problem of finding a distributor that carries sufficient stock of the required sensors. This challenge is particularly pressing in industries that operate with lean inventory models or require just-in-time manufacturing.

Thankfully, DigiKey stands out in the industrial sensor market by offering an extensive range of high-quality sensors from industry leading suppliers. This will be further explored later in the article.

Figure 3: An optical sensor utilized in an automation machine vision inspection tool. (Image source: Adobe Stock)

What to prioritize when selecting an industrial sensor

When selecting an industrial sensor, following a structured decision hierarchy can simplify the process and ensure that the chosen sensor meets the application's requirements. Generally, a decision hierarchy can be followed that looks something like this:

• Sensor type – What does the sensor need to detect?
• Sensor certifications – Does the sensor need to adhere to any specific certifications or standards?
• Ability to communicate – Does the sensor have the capability to communicate with existing automation infrastructure?
• Inventory & availability – Is the sensor readily available, what are the lead times, are there support services available?
• Price – Is the price of the sensor cost-effective, in terms of initial costs, total costs of ownership, and return on investment, for the project?

Following this structure when selecting an industrial sensor can help customers narrow down options and find the most suitable sensors that meet technical requirements, comply with certifications, integrate successfully, are readily available, and do not break the bank.

The DigiKey offering

DigiKey offers a wide range of industrial sensors to fit almost any need. Its extensive range of magnetic, proximity, pressure, and optical sensors includes big names such as SICK, Honeywell, Banner Engineering, Pepperl+Fuchs, Endress+Hauser, and many more.

Figure 4: The SNG-SPRC-002 (top) and SNG-SPRD-004 (bottom) from Honeywell. (Image source: Honeywell)

Honeywell’s SNG-S series speed sensors are a great example of DigiKey’s magnetic sensor range, featuring a specially designed IC and a permanent magnet encased in rugged, probe-type packages. These sensors detect changes in the magnet’s flux density when approached by ferrous metal, supplying a digital pulse output with a frequency proportional to the speed of a gear wheel. The sensor's performance depends on factors such as target material, geometry, speed, sensor/target gap, and temperature. The SNG-S series offers a wide operating temperature range of -40°C to +140°C, is insensitive to angular rotation during assembly, and provides environmental sealing with an IP69K rating. Additionally, it boasts robust electrical noise immunity rated to 100 V/m, zero-speed detection, high-frequency switching capability from 0 Hz to 15 kHz, and an O-ring seal for secure mounting. The sensors are compatible with supply voltages from 4.5 V to 24 V and are CE-certified.

Figure 5: The K50RF-8060-LDQ radar sensor from Banner Engineering. (Image source: Banner Engineering)

Banner Engineering’s K50R R-GAGE radar sensor series highlights one of DigiKey’s extensive proximity sensor ranges, offering a robust, cost-efficient solution for both indoor and outdoor environments. Available in 40° x 30° models for precision comparable to ultrasonic sensors and 80° x 60° models for broader coverage, these sensors are ideal for applications like automated guided vehicles (AGVs), tank level management, and vehicle detection at EV charging stations. The K50R series offers simple integration through Banner Measurement Sensor software and features dual discrete and analog output options, with various mounting accessories for flexible installation. With an IP67 rating, the sensors are protected against rain, snow, fog, steam, wind, and sunlight, ensuring superior operation in any environment. They are immune to dust, dirt, and steam, have minimal temperature effects for stable measurements, and offer a wide 5 m measuring range with a 50 mm short dead zone. Additionally, they allow for the close mounting of multiple sensors without interference, thanks to the absence of crosstalk.

Figure 6: Endress+Hauser’s Cerabar PMC21 series compact pressure transmitters. (Images source: Endress+Hauser)

Endress+Hauser's Cerabar PMC21 series compact pressure transmitters feature ceramic, oil-free sensors designed for durability and resistance to pressure shocks. Their ceramic cells excel in low-pressure and vacuum applications. The PMC21 series measures both absolute and gauge pressures ranging from 100 mbar to 40 bar. Communication is facilitated primarily through a 4 mA to 20 mA signal, connected via an M12 or valve plug. The sensor range and process connection should be tailored to meet specific application needs. Built for the demanding environments of the process industry, these transmitters boast ingress protection ratings up to IP68, a highly durable Ceraphire membrane, and a 316L stainless steel housing. With multiple certifications, including hazardous area and marine approvals, they are suitable for a wide range of applications. Users benefit from the devices' ease of use, high performance, long-term stability, and superior material quality.

DigiKey also has a fantastic range of optical sensors on offer for its customers, such as the Pepperl+Fuchs VOC industrial event camera or the CLV69x series from SICK.

Figure 7: The VOC10M-F256-B12-V1D-CR03 from Pepperl+Fuchs. (Image source: Pepperl+Fuchs)

The VOC industrial event camera from Pepperl+Fuchs is designed for event-driven video recording up to 60 seconds before and after a trigger signal, facilitating targeted remote diagnostics and automatic documentation. The camera captures video when a malfunction, predefined status or process occurs, with automatic timestamping and a User Datagram Protocol interface for dynamic text overlays, making file retrieval quick and easy. Ideal for monitoring automated high-bay warehouses and security applications, it features a web interface for accessing video files and live streams, a video ring buffer for automatic recording, and triggers via UDP, REST API, or digital hardware input for integration. The camera supports mounting distances from 0.05 m to infinity, offers resolutions up to 1280 x 720 (HD), and can store up to 10,000 events on an 8 GB microSD card. It operates on 18 VDC to 28 VDC and uses protocols like TCP/IP, HTTP, FTP, and RTSP, with an IP65 protection rating.

Figure 8: The CLV690-1000 (left) & CLV691-0000 (right) from SICK. (Image source: SICK)

SICK’s CLV69x series of barcode scanners come with built-in SMART+ code reconstruction technology, allowing the device to read even contaminated and damaged barcodes. These fixed-mount 1D barcode scanners provide excellent reading performance, high-speed processing, and high accuracy, with an autofocus feature that uses built-in distance measurement for height-independent code reading within the scanning field. Additionally, the user-friendly SOPAS ET operating system ensures simple parameterization. With integrated tracking, the scanner can manage standard applications without requiring an additional system controller. Its innovative connectivity, including built-in parameter storage, allows for quick scanner replacement and easy integration across various applications. Key features include real-time autofocus for a large depth of field, flexible cloning plug technology, CAN, Ethernet, and serial communications, as well as advanced sorting, filtering, and logical functions. An integrated LED bar graph with pushbuttons enhances usability.

Conclusion

DigiKey’s broad selection of industrial sensors ensures that customers find the right sensor for their specific needs, providing unparalleled value in the automation industry. SICK and Banner are renowned for their advanced sensors and innovative contributions to IoT integration. Pepperl+Fuchs excels in sensor communication, while Endress+Hauser leads in measurement instrumentation, particularly for pressure and fluid measurement sensing. Although a smaller player, Honeywell offers specialized sensors that enhance DigiKey’s diverse portfolio, which is more expansive than any of its competitors.