6 Sensor Selection Criteria for Finding the Right Sensor

Tuesday, January 12, 2021

Manufacturing Has Changed — Can You Keep Up?

As a manufacturer, you know the pressures facing your organization today. While 2020 brought much uncertainty, a recent survey of senior leaders in manufacturing and distribution companies noted modest to significant growth in revenue during the pandemic. Demand for a variety of products across multiple industries is surging, particularly in markets where the shutdown of last year caused companies to fall behind.

While the shutdown was challenging, it was a blessing in disguise in that it accelerated many companies’ moves to become more efficient and resilient in the face of future uncertainty. This focus — along with expectations of increased localized production due to tariff concerns and faster digital transformation to reduce reliance on labor — means companies need more advanced solutions in place now to achieve those goals of efficiency and resiliency. As a contributor to Forbes recently noted:

“Advanced technology — sensors, machine learning, computer vision, robotics, cloud computing, edge computing, and 5G network infrastructure — has proven to increase supply chain resiliency for manufacturers who adopt it.”

Sensors aren’t new to the manufacturing industry, but if your organization is using sensors that are several years old, it’s likely that its sample speed is vastly behind the capabilities of today’s sensors. A new solution is needed, but where do you begin? Here, we’ll explore six sensor selection criteria so you have a starting point for your search.

Sensor Selection Criteria for Reliable Results

1. Know the Goal

The first sensor selection criterion is understanding your goal and target. As with any equipment purchase, you don’t know what you need until you understand the need. When it comes to sensors, this is important because most sensor types detect a single characteristic or condition that causes reflected light to be above or below a threshold. If there will be multiple characteristics, you may be able to use a color sensor or multiple contrast sensors.

Questions to consider: Are you trying to distinguish one color from another, ensure that a product color is always the same, or verify the presence of specific marks or materials? Will those targets remain consistent from one product to another, or will there be a significant variation? And what about the environment — will the same conditions for the application always be the same, or will light and other conditions shift?

2. Know the Target Surface

Depending on whether the surface of your target material is glossy and highly reflective or matte, you will need to mount the sensor in a specific orientation. Glossy/reflective surfaces generally require a slightly angled mounting configuration, e.g., 15º from perpendicular. If the glossy characteristic itself needs to be detected, perpendicular mounting is necessary. For matte surfaces, the sensor orientation is more flexible because the material diffuses light more consistently than a glossy surface. This is an important sensor selection criterion to note because not all sensors feature flexible mounting options or additional accessories to ensure proper integration into your production environment.

3. Know the Mark/Object Size

To detect their target, sensors emit light at a certain size referred to as the spot size. Spot size can vary significantly. Because of this, it’s important that the target is larger than the spot size to ensure reliable and consistent operation. If you need to detect a small UV marking that’s 2 mm long, you wouldn’t want a sensor with a 25 mm spot size.

It’s important to know the size of the target or object for considering speed as well — particularly in fast-moving production lines. Reliable detection requires the target to be present in the sensor light spot long enough to be acknowledged by the sensor; otherwise, it won’t be able to accurately and reliably detect the target — negating the purpose of the sensor in the first place.

4. Know the Target Speed

In all but the slowest-moving production lines, understanding the speed at which the target will be moving under the sensor is essential for reliable detection. In addition to the speed of the target, the sensor’s response time, sampling rate, and the size of the target all contribute to successful detection. And as mentioned above, the target must be in the sensor’s light spot long enough for the sensor to trigger a response. Sensors that have response times faster than 100uS are generally suitable for all but the highest speed/smallest target applications.

5. Know the Distance from Sensor to Target

Another important sensor selection criterion is understanding the space between the sensor and the target in the production line. Most sensors don’t operate at distances greater than 100 mm — applications at or above that figure will require a higher-sensitivity (and potentially higher cost) sensor. When evaluating sensors based on distance, it’s best to choose a sensor that will provide reliable detection and place it at the optimum distance rather than fix a distance requirement and try to find a sensor that will work.

6. Know Your Target’s Stability

Another factor in successful detection is knowing whether your application will see variations in the sensor-to-target distance (known as “flutter”). Because sensors measure differences in light collected by sensor optics, changes in distance will cause changes in the light perceived. Whether this causes an issue with reliable detection depends on the difference between presence and absence levels. If there will be a greater difference, then a greater allowable distance variation must be considered.

Find the Right Sensor with EMX Industries

As sensor manufacturing experts with proven success in multiple applications, our team understands the various sensor selection criteria that must be navigated to identify and implement a successful solution. Whether it’s our UVX series for detecting luminescence, our ColorMax series for verifying and measuring color on various materials, or any one of our many specialty sensors, we offer a full portfolio of industrial sensors to automate and streamline your production with pinpoint accuracy.

The first step is discussing your application with our engineering team. We’ll then conduct a test using the most likely sensor solution and will provide you with a written report detailing how the sensor will perform, what the ideal mounting and distance configurations should be, and other valuable information.

Connect with us today to schedule your complimentary sensor test.