Mitch Andrejka, Product Marketing Manager – Sensors at Banner Engineering, deep dives into photoelectric, laser measurement, and 3D time-of-flight sensors, shares tips for selecting the right sensors and sensing modes for your unique application demands, and introduces three Banner sensor series engineered to overcome a variety of common industrial automation challenges.
Sensors are a vital link in the chain of connectivity that drives the implementation and evolution of Industry 4.0. They are the “eyes” that monitor and measure operations in the industrial automation environment and are key to driving efficiencies on assembly lines and the factory floor.
To learn more about industrial automation sensors, we spoke with Mitch Andrejka, Product Marketing Manager – Sensors at Banner Engineering. Mitch provided comprehensive introductions to photoelectric, laser measurement, and 3D time-of-flight sensors, shared tips for choosing the right sensors and sensing modes for your unique application demands, and introduced three Banner Engineering sensors engineered to help customers overcome common sensing challenges in almost any industrial application.
Q1. Hi Mitch. Please introduce yourself and tell us about your role at Banner Engineering.
I earned a Bachelor of Science degree in Applied Physics from the University of Wisconsin and, after eight years in the workforce, joined Banner Engineering as an application engineer in the Applications group. Within two years, I transitioned into the product management group for the Sensors business unit. I’ve now been at Banner for over six years and work as a product marketing manager, which means I’m involved with the strategy and marketing of sensor products from development through market launch and beyond.
Q2. Please also provide us with a brief introduction to Banner Engineering.
Banner Engineering is a leading global manufacturer of non-contact sensors and other industrial automation products, including LED lighting and indicators, smart IIoT and wireless communication technologies, measurement devices and monitoring solutions, machine safety equipment, and other connectivity products.
One unique aspect of our company is that, if you need support, a human will pick up when you call. That immediate human response is hard to find these days, but we believe it’s important for building relationships with our customers and getting them the right solution faster.
Q3. You joined us today to talk about sensors and measurement. Sensors have played a critically important role in the implementation and evolution of Industry 4.0 technologies. Please tell us more about these impactful devices.
Without sensors, the chain of connectedness that drives Industry 4.0 is broken before it even starts. Sensors are called “photo eyes” for a reason — they’re the eyes and ears on the ground detecting whether something is in the target area and reporting information back to you. As technology has evolved, sensors have too, providing much more information now than in years past. Photoelectric, laser distance measurement, and multipoint or 3D time-of-flight sensors have evolved to improve productivity, simplify processes, and reduce costs in industrial automation.
Photoelectric sensors are very good for presence/absence applications or detecting changes in surface conditions of a target. As such, they’re very common in material handling and packaging, food and beverage, and other industrial manufacturing applications.
Laser distance measurement sensors provide single-point distance measurements and are ideal for use in a wide variety of discrete, analog, and IO-Link applications where long-range detection, high precision, or problem-solving is required. They’re particularly useful for detecting dark or challenging targets and small features, due, respectively, to their high excess gain and small spot size.
Multipoint or 3D time-of-flight sensors have a wide detection range and are designed to distinguish a single object in a 3D field of view. They use multiple points of data to create a point cloud that accurately defines what the sensor is seeing.
Q4. Let’s dive into some of the different types of sensors you mentioned, starting with photoelectric sensors.
Photoelectric sensors have an emitter and receiver that can be in the same housing or separate housings, and the emitter sends a beam of light that’s detected by the receiving element. When a product or target breaks or reflects the beam of light, an output switch sends an electronic signal to a control device.
These general-use sensors are widely employed in most industrial market segments and are commonly used for leading-edge detection, where an object moves down a line or conveyor belt. In this type of application, photoelectric sensors identify the leading edge of an item, such as the front of a box on a conveyor, to help operators track exactly where objects are on the line. Knowing the location of items involved in the manufacturing process ensures the accuracy of actions like label stamping and sleeve wrapping.
Photoelectric sensors are also used for quality control and counting. They can tell you whether a certain part is present and in the right place in an assembly or count a row of moving targets, like 250 pills being filled into a bottle. In this instance, every time a pill drops in, the sensor detects and counts it and, once the pill count reaches 250, tells the connected control devices to stop the process and move on to the next bottle.
This particular task was previously executed using a contact sensor solution that counted each pill as it fell into the bottle and made contact with the switch. The problem with this approach is that mechanisms that move will eventually wear out and need to be replaced and, in this example, filling a single pill bottle would move the counting switch 250 times. Contact sensors have a spec for how many actuations they can make before they need to be replaced, and — depending on the application they’re developed for — can withstand 10 or 10 million actuations before wearing out.
Photoelectric sensors are non-contact, and thus don’t have any moving parts that can wear out. Environmental conditions and power cycling can potentially affect their lifetime, but these sensors should still last for decades. For example, when I was in the Applications group at Banner, one of my colleagues got a call from a customer about a sensor that had just worn out. We got the date codes from them, and the date was from before he was born!
Photoelectric sensors use various detection methods called sensing modes, and it’s important to understand the different sensing modes and their advantages.
- Opposed mode or through-beam models have the emitter and receiver in two separate housings. The object breaks the beam, and the output switches. Because there’s a direct transmission of light from emitter to receiver, this mode can capture long ranges with high excess gain, or light energy. The more excess gain a sensor has, the more dust and debris it can see through to still accurately detect a target. The downside to this mode is that you need to apply power to both sides. So, if you place the emitter and receiver 20 meters apart, you need a cable run that will run 20 meters to power both sides.
- Retroreflective mode is similar to opposed mode, but the emitter and receiver are in the same housing, and this mode uses a reflector to send the light back. This is a very common sensing mode for the material handling industry and is typically used when electrical power is only available on one side of the installation or when space is limited and opposed mode wouldn’t be possible.
- Diffuse mode sensors also have the emitter and receiver in the same housing, but instead of using a receiver or retroreflective target, it uses the actual target to bounce light back to receiver. So, its reliability depends on the properties of the target. For example, white reflects more light than black, so you’ll be able to see something white at a distance better than something black. However, targets like cardboard that don’t reflect light back as well as white targets tend to be more common on balance, as do darker backgrounds that targets can more easily blend into. So, that’s a critical consideration when choosing a diffuse sensor. They work very well in applications where you can control the background.
Background suppression is an overarching sensing mode that’s available in adjustable- and fixed-field sensors. Both use this mode to suppress or ignore the background by setting a cutoff distance. The sensors will see anything in front of the cutoff, and anything beyond it will be ignored. This makes sensing less-reflective targets easier because the proximity of the target to the sensor is significantly more impactful than the color of the target. Fixed-field sensors have a fixed cut-off distance, so there’s no configuration needed before mounting it. Adjustable-field sensors allow you to adjust where the threshold is, giving you more flexibility. If you have multiple applications that need a sensor and they all have different cutoff requirements, you’ll want adjustable-field sensors.
Q5. Please tell us more about laser distance measurement sensors.
Laser distance measurement sensors can offer some advantages over diffuse or background suppression photoelectric sensors. They have longer ranges, higher excess gain, which makes it easier to see challenging targets, and small spots for easy alignment and small part detection. They also can provide more information given their ability to accurately measure where the target is.
These sensors use two different types of technologies to measure distance:
- Triangulation. Triangulating the angle from the emitter to the receiver and then figuring out the distance from the target is a very good method for getting precise measurements, but accuracy is better in the near range and degrades as the target moves farther away.
Time-of-flight. Calculating a distance using the time it takes light to travel from the sensor to the target and back offers coarser accuracy in the near range than triangulation but remains much more consistent throughout the entire range of the sensor.
Laser measurement sensors are available in discrete, analog, and IO-Link variants optimized for a wide variety of sensing applications.
- Discrete sensors look for presence and absence. Visible red lasers provide a small spot size to line up the target, and high excess gain enables the sensors to see even dark, challenging targets, like black foam. Quality inspections, like inspecting a car door assembly to make sure all parts are in place before it moves down the line, are a common application.
- Analog sensors provide an actual measurement, like “Target X is six inches from the sensor,” which is beneficial in applications like measuring the diameter of a roll of labels because, in addition to alerting operators when the roll is low or out so they can replace it, it reveals how quickly you’re going through labels.
- IO-Link is a popular one-wire serial protocol that reduces wiring complexity, sends all kinds of information from sensors to their controllers, and offers many other advantages in industrial automation environments. Since these sensors have the ability to send and receive commands, you can program them to provide the data you want — for instance, an actual measurement value, like 600 mm, or an excess gain value — and, when the output switches, to incite an action, like turning on a light or other indicator to show a status or value.
Q6. You also mentioned 3D measurement sensors and multipoint sensors. Please introduce us to those as well.
Multipoint or 3D time-of-flight sensors are like laser measurement sensors, but instead of a single receiver or a single point, they have a pixel array, and each pixel acts like a single-point sensor. All that sensor information is then combined to create a point cloud that can help users answer questions like, “What is the closest thing to the sensor?” Because of their wide detection range, these sensors are more adept at picking up a target that is not at the exact same point every time, like a product dropped onto a moving conveyor belt, than a single-point laser sensor is.
We see a lot of success with 3D time-of-flight sensors in bin fill applications, which are widely used in material handling applications where fill information is critical. An example is the image on the right below. If a single-point laser sensor were mounted directly over the middle of the bin looking straight down, the sensor might read one point as a package poking up or a hole going straight to the bottom. With 3D time-of-flight sensors, there’s a wide beam over the entire area of the bin. This generates a much more accurate picture of all the peaks and valleys and calculates the volumetric measurement that identifies how full the bin is in real time.
Q7. What common challenges do people face when it comes to selecting and implementing sensors, and do you have any advice for overcoming these challenges?
With so many different sensing technologies, sensing modes, and even sensor families with different specializations (e.g., long-range detection, high precision, small form factors), it can be challenging for customers to select the right sensor for their applications. Their best bet is to talk to product and technical experts available through vendors like us and distributors like RS.
Customers should prioritize their application needs by answering the following questions before reaching out to a product expert:
- What’s the target that the sensor needs to see? Include the size, shape, color, and material.
- How far away will the target be, and how fast will it move?
- What is the sensor output that you require? This could be on/off, measurement, advanced diagnostics, or another type of output.
- What kind of environment will the sensor live in? Think about whether it will be cold, hot, dusty, dirty, wet, indoors, or outdoors.
- What kind of precision do you require — coarse or fine measurement?
Photoelectric sensors tend to have very fast response speeds, which can be a great benefit in many applications. 3D time-of-flight sensors do a lot more thinking than a photoelectric sensor, so their response speeds are slightly slower. The key is to analyze the application and what you’re trying to do to guide your decision.
Q8. Please introduce us to Banner’s sensor product portfolio.
Banner offers a comprehensive range of sensors designed to help solve a wide variety of application challenges. We offer photoelectric sensors to more complex solutions like 3D time-of-flight sensors and everything in between. A big advantage of our sensors is that they are all non-contact, which means they can be mounted away from the machine, product, or target and still deliver reliable measurement and detection. This offers customers more flexibility and helps eliminate any interference with machines or production lines.
Q9. Please introduce us to Banner’s QS18 Series all-purpose photoelectric sensors.
I call the QS18 photoelectric sensors Banner’s “bread and butter” sensors. The QS18 Series has one of the most comprehensive ranges of sensing modes available, offering 10 sensing modes compared to the three or four sensing modes most competing photoelectric sensors offer. Having 10 sensing modes in one familiar form factor allows customers to standardize cables and brackets and use the same sensor family to satisfy the unique needs of a variety of different applications.
The QS18 family also offers simple plug-and-play sensors on up to more advanced configurations and IO-Link versions that allow you to set up specific teach functions and diagnostics. It’s commonly used for leading-edge detection applications.
Our other photoelectric sensor families include the Q20 Series, which features a rectangular form factor widely used in European markets, and the QS30 Series high-performance long-range sensors, which has a 30mm barrel instead of the 18mm barrel on the front of the QS18 for more power. It can also reach 60 meters as opposed to the 20m range of the QS18. For harsh washdown environments, we have the ultrasonically welded, epoxy encapsulated T18-2 photoelectric sensors, and for space-constrained applications, we have the Q2X Series miniature photoelectric sensors.
Q10. Please introduce us to Banner’s Q4X Series rugged laser distance sensors.
Banner’s Q4X Series is like the Swiss Army Knife of sensors, offering a best-in-class combination of range (600 mm), precision, and versatility. Customers can fully configure each sensor with a few buttons and the display, and a single SKU can solve a wide range of different applications based on how you configure it, which is a huge selling point for many of our customers.
As a laser sensor, the Q4X has high excess gain to detect dark, challenging targets across a wide variety of materials and color. This feature and its metal housing make it very popular in the automotive market. The Q4X is also used in washdown applications in the food and beverage industry. It’s not hygienic, but it is stainless steel, and we offer it in both discrete and analog versions, unlike most competitors, who don’t have analog options at this price point.
If you need more range, our Q5X Series high-power multifunction laser sensors go up to 10m, and our LTF Series long-range time-of-flight sensors offer two high-power models (12m and 24m). For more precision, our LE Series laser displacement sensors offer sub-millimeter resolution, making it very accurate at respectable ranges (400mm to 1m).
Our most accurate laser sensor is the LM Series, which is available in two versions: the LM150 with 4 µm resolution and the LM80 with 2 µm resolution. These sensors are often used for thickness measurements, like for sheet metal or corrugated cardboard, or to make sure that the crankshaft in a vehicle or machine is properly tuned, as they can ensure that there’s no up and down movement that would cause vibration or other problems down the road.
Banner Engineering’s Q4X Series rugged laser distance sensors are ideal for applications including bottle fill level detection (left), detecting black parts on black backgrounds (center), and measuring both distance and intensity (right), which can be especially useful on assembly lines.
Q11. Please introduce us to Banner’s K50Z Series multipoint sensor.
K50Z Series sensors are one of lowest cost 3D time-of-flight, multipoint sensors available and are perfect for monitoring a wide area. They provide a 45° x 45° view and 64 measuring points and are widely used for bin filling applications to accurately account for the peaks and valleys involved with volumetric measurement.
The K50Z Series also has two independently configurable output zones. The image on left below shows a bin fill of scrap metal from a CNC. The red area shows one zone measuring the overall fill of the bin, so that when it gets full someone will know to come and replace the bin. The blue area measures directly below the outfeed. Since this area fills faster and will cause a clog if it gets too high, the sensor triggers an alarm when someone needs to come rake down the area to make more room to keep filling the bin. These two independently configurable zones allow the K50Z to replace multiple sensors with just one, which can reduce cost and complexity, as well as possible points of failure.
On pallet wrappers (see the middle application image below), the wide area of detection enables the K50Z to maintain detection despite the different angles involved as the arm rotates around the target. As the arm goes up, the sensor will eventually lose sight of the target, and that’s how the machine knows it’s reached the top. Other types of sensors may lose detection prematurely, resulting in a partially wrapped pallet, but the K50Z maintains detection all the way to the top.
Our ZMX Series 3D time-of-flight sensor operates on same principle but, instead of the K50Z’s 8×8 pixel array, has a 272×208 pixel array with 56,000 measuring points. That finer resolution paints a much cleaner picture of what the sensor sees. For most applications, the K50Z does a very good job, but if you need extra precision and extra resolution then you want the ZMX.
Q12. Is there anything else you’d like our customers to know about sensor and measurement solutions, Banner Engineering, or the sensor products you’ve introduced here?
Banner offers a wide variety of sensing solutions optimized for industrial automation applications. So, if one technology or sensor family won’t solve your application challenges, it’s very likely that we have another one that will. Banner’s Applications team also excels at advising customers and finding the right sensors for their critical challenges. And because customers don’t always need all the features or information that our more advanced sensors provide, we always look for the lowest cost option that will satisfy their needs.
Banner Engineering and RS: Your Trusted Sensor & Measurement Solutions Suppliers
Banner Engineering is a leading global supplier of industrial automation solutions, including non-contact sensors, wireless solutions, machine safety, and LED lighting for indication and operator interface and control — all of which are designed to enhance productivity, reduce costs, simplify processes, and improve quality.
RS offers a vast selection of Banner’s industrial sensor and measurement solutions, including the QS18, Q4X, and K50Z Series sensors Mitch discussed here. For more information about these sensors, other photoelectric, laser measurement, and 3D time-of-flight sensors from Banner available at RS, or the complete RS portfolio of Banner Engineering products, visit the links embedded here and throughout his article. For more expert insights from Banner Engineering, click to view their other contributions to the RS Expert Advice Series, which address condition monitoring, IO-Link, and other sensor and industrial automation topics. For assistance identifying, procuring, deploying, and maintaining Banner Engineering sensors optimized for your industrial automation applications, please contact your local RS representative at 1.866.433.5722 or reach out to the RS technical support team.
