Detecting Fill Levels With Direct Contact and Non-contact Capacitive Sensors

Capacitive sensors are commonly used in level detection applications. Specific capacitive sensors can supply better solutions than others depending on the type of media you may be detecting and if the sensor will be in direct contact with that media. Keep reading to decide which type works best for different application solutions.

Non-contact capacitive sensors

Capacitive sensors are great for monitoring the fill level of non-conductive materials. In many cases, the capacitive sensor doesn’t need to physically touch the media it is detecting; rather, it can sit outside a thin, non-metal container or pipe. As the level rises or falls, the capacitive sensor can signal if the medium is there. Since non-contact capacitive sensors sit outside the medium, there shouldn’t be any interference or false readings from direct contact with the material.

Selecting the correct capacitive sensor for these applications is important. While you don’t have to risk contaminating the sensor face (and getting a false read) in non-contact applications, you need to keep in mind other factors that can cause a sensor to false trip. One thing that is important to keep in mind with externally mounted capacitive sensors is that viscous materials can still leave a layer of residue on the inside walls of tanks or basins. While the sensor face is not covered, if you select the wrong type of sensor this build up on the wall can cause a false reading (such as reading as reading the tank as full when it is actually half-empty).

Another thing to keep in mind when selecting the correct capacitive sensor for a non-contact application is foam. In applications such as bottling beer in glass bottles, most standard capacitive sensors will detect presence once that layer of foam reaches the sensor face. While the foam may be at the sensor face, the bottle could still be only half way full of actual liquid. Making sure you select a sensor that can account for things like foam is something to keep in mind as well.

There are many benefits when using non-contact capacitive sensors in fill level applications. Not every application requires direct contact with the medium, and not every application even allows for the medium to be touched directly. There are many capacitive sensors in many form factors that are used every day for fill level applications, but making sure the right sensor is selected is important.

Contact with media capacitive sensors

In certain applications, the capacitive sensor will only be able to detect the fill level of a container, pipe, or tank if it is in direct contact with the media it’s trying to sense.

For various reasons, a sensor must be in direct contact with a media like oil, paint, powder, or paste. You may need to place a sensor directly in a tank because the tank is made of metal, or possibly because the walls of the tank are too thick for a capacitive sensor to sense through. Direct contact applications can be difficult to find solutions for if you are not aware of what capacitive sensors are capable of.

There is a way to fix issues such as false tripping in sticky substances.

Advanced technologies allow for capacitive sensors that mask residual build-up or foam when sensing in direct media contact. These level-sensing capacitive sensors are great for applications in the food and beverage industry and for detecting practically all the same materials as non-contact capacitive sensors. In areas of detection where adhesive substances may stick to the sensor face is a perfect application for direct contact capacitive sensors. Some typical direct-contact applications include areas such as vegetable oil or ketchup container fill levels, hydraulic oil levels in a hydraulic cylinder, or even the amount of flour in a container.

For instance, if you stick a capacitive sensor inside a tank of oil to monitor the fill level, the sensor face will get covered in the oil. As the level in the tank drops below the sensor face, that oil will remain on the face. So, even if the tank is empty, the sensor will always detect something. With specialized capacitive sensors that ignore build-up, adhesive or viscous media that typically influence detection is no longer a concern.

Another use for capacitive sensors that allow for direct media contact is for leak detection. If a tank, pipe, or tub is known to leak, there are capacitive sensors that can be mounted to the ground in the area that puddles form. In some instances you know a machine could potentially leak, and puddles form in an area you can’t regularly see, which is where these sensors are perfect for application. Depending on the situation, some of these sensors can be mounted a couple millimeters to an inch off the ground waiting for a leak. As a puddle forms and reaches the sensor’s switching range, maintenance can be alerted of the issue and work to fix it.

Reduce time and costs associated with manual level-checking

Another application for a capacitive sensor with direct media contact capabilities is within the automotive industry. Inside the painting process of an assembly plant, for example, you must be able to monitor the fill levels of the e-coat, the primer, the base coat, and the clear-coat paint tanks. Without a sensor to determine the fill levels, the time and energy and dollars it can cost the workforce to manually check the fill levels can be high.. Luckily, these contact-capacitive sensors can monitor viscous media like paint, reducing the time and costs associated with manual level-checking.

While non-contact and contact capacitive sensors perform the similar functions, they are used in different applications. Some applications allow a sensor to sit outside a container or tank and detect through the walls, while others require direct contact. Now that you understand the differences and their strong points of application, you can determine which sensor is best for you.

Choosing the Right Sensor for Measuring Distance

Distance-measuring devices help with positioning, material flow control, and level detection. However, there are several options to consider when it comes to choosing the correct sensor technology to measure distance. Here I’ll cover the three most commonly used types in the industrial automation world today, including photoelectric, ultrasonic, and inductive.

Photoelectric sensors

Photoelectric sensors use a light source, such as a laser or light-emitting diode, to reflect the light off an object’s surface to calculate the distance between the face of the sensor and the object itself. The two basic principles for how the sensor calculates the distances are the time of flight (TOF) and triangulation.

    • Time of flight photoelectric distance measurement sensors derive the distance measurement based on the time it takes the light to travel from the sensor to the object and return. These sensors are used to measure over long distances, generally in the range between 500 millimeters and up to 5 meters, with a resolution between 1 to 5 millimeters, depending on the sensor specifications. Keep in mind that this sensor technology is also used in range-finding equipment with a much greater sensing range than traditional industrial automation sensors.

    • In the triangulation measurement sensor, the sensor housing, light source, and light reflection form a triangle. The distance measurement is based on the light reflection angle within its sensing range with high accuracy and resolution. These sensors have a much smaller distance measurement range that is limited to between 20 and 300 millimeters, depending on the sensor specifications.

The pros of using photoelectric distance measurement sensors are the range, accuracy, repeatability, options, and cost. The main con for using photoelectric sensors for distance measurement is that they are affected by dust and water, so it is not recommended to use them in a dirty environment. The object’s material, surface reflection, and color also affect its performance.

Photoelectric distance measurement sensors are used in part contouring, roll diameter measurement, the position of assemblies, thickness detection, and bin-level detection applications.

Ultrasonic sensors

Ultrasonic distance sensors work on a similar principle as photoelectric distance sensors but instead of emitting light, they emit sound waves that are too high for humans to hear, and they use the time of flight of reflecting sound wave to calculate the distance between the object and the sensor face. They are insensitive to the object’s material, color, and surface finish. They don’t require the object or target to be made of metal like inductive position sensors (see below). They can also detect transparent objects, such as clear bottles or different colored objects, that photoelectric sensors would have trouble with since not enough light would be reflected back to reliably determine the distance of an object. The ultrasonic sensors have a limited sensing range of approximately 8 meters.

A few things to keep in mind that negatively affect the ultrasonic sensor is when the object or target is made of sound-absorbing material, such as foam or fabric, where the object absorbs enough soundwave emitted from the sensor making the output unreliable. Also, the sensing field gets progressively larger the further away it gets from the sensing face, thus making the measurement inaccurate if there are multiple objects in the sensing field of the sensor or if the object has a contoured surface. However, there are sound-focusing attachments that are available to limit the sensing field at longer distances making the measurements more accurate.

Inductive sensors

Inductive distance measurement sensors work on the same principle as inductive proximity sensors, where a metal object penetrating the electromagnetic field will change its characteristics based on the object size, material, and distance away from the sensing face. The change of the electromagnetic field detected by the sensor is converted into a proportional output signal or distance measurement. They have a quick response time, high repeatability, and linearity, and they operate well in harsh environments as they are not affected by dust or water. The downside to using inductive distance sensors is that the object or target must be made of metal. They also have a relatively short measurement range that is limited to approximately 50 millimeters.

Several variables exist to consider when choosing the correct sensor technology for your application solution, such as color, material, finish, size, measurement range, and environment. Any one of these can have a negative effect on the performance or success of your solution, so you must take all of them into account.

On the Level: Selecting the Right Sensor for Level Detection

We’ve probably all experienced having the “pot boil over” or “run dry” at one time or another. The same is frequently true on a much larger scale with many industrial processes. These large events can prove costly whether running dry or overflowing, resulting in lost product, lost production time, damage to the tank, or even operator injury. And then there is the cleanup!

The fact is, many procedures require the operator to monitor the bin or tank level – especially on older equipment. This human factor is prone to fail due to inattention, distractions, and lack of proper training. With today’s employee turnover and the brain drain of retirements, we need to help the operators out.

Multiple solutions exist that can provide operators with sufficient warning of the tank and bin levels being either too low or too high. This article provides a framework and checklist to guide the selection of the best technology for a specific application.

What type of monitoring is necessary?

First, consider whether the application requires or would benefit from continuous monitoring, or is point-level monitoring all that is needed?

    • Point-level monitoring is the simplest. It is essentially sensing whether the product is present at specific detection point(s) in the tank or bin. If the goal is to avoid running dry or overflowing, monitoring the bin or tank point level may be all that is required. Point-level sensors typically are best if the product levels can be detected through the wall or inside the tank or bin itself. A number of sensors can prevent false readings with products that are viscous, leaving residue on the sensor, and even ignore foam.
    • Continuous-level monitoring detects levels along a range – from full to empty. This is required when the exact level of the product must be known, such as for batch mixing.

Checklist for sensor selection

The checklist below can help guide you to what should be the appropriate technologies to consider for your particular application. Frequently, more than one type of technology may work, given the media (or product) you’re detecting, so it may make sense to test more than one.

Checklist for sensor selection

Ultimately, the sensor(s) you select must reliably sense/detect the presence of the subject product (or media). Which solution is least costly is frequently a big consideration, but remember there can be a hefty cost associated with a sensor that gives a false reading to the operator or control system.

Choosing sensors for washdown or clean-in-place environments

For products that will be consumed or entered into the human body, further selection considerations may include sensors that must survive in washdown or clean-in-place environments without contaminating the product.

The encouraging news is that sensors exist for most applications to detect product levels reliably. The finesse is in selecting the best for a given application when multiple technologies can do the job.

Again, there may be some trial and error at play but this checklist should at least narrow the field and pointed you to the better solution/technology.

Reducing Assembly Line Mistakes With the Error Proofing Platform Station

About 18 months ago, one of the major automotive companies came to the Indicon Conference looking for a way to decrease mistakes on the assembly line. They found a solution in a concept named the Error Proofing Platform Station (EPP).

How it works

The EEP works by using a bar code reader, in this case a scanner, to verify that the correct parts are being used in the assembly process. The scanner connects to an RS232-to-digital-converter module, and from there to an IO-Link networking block which enables two-way communication of information with the PLC. IO-Link blocks can connect hundreds of devices, versus traditional blocks that can only connect eight to sixteen devices. This greatly simplifies the hardware, cabling and installation costs.

EEP station design

The overall design of this EPP station grabbed the automotive company’s attention for several reasons.  It is effective both in its simplicity as well as the small footprint that it takes up. The design of the components allows it to sit on the plant floor instead of having to be installed in a cabinet like previous designs. They especially liked the wiring design where a single cable goes from the IO-Link block at is managed by a single IP address back to the PLC. Should one of the devices fail, you simply replace a single cable or device and move on.

The old days of unwinding the cables and spending hours trying to decipher which cable goes to which device are gone.

The current roll-out has been at four separate plants with plans for 10 more in the next four years. Expansion of this innovation is being targeted toward the other major manufacturers.

Choosing a Contactless Sensor to Measure Objects at a Distance

Three options come to mind for determining which contactless sensor to use when measuring objects at a distance: photoelectric sensors, ultrasonic sensors, and radar detection. Understanding the key differences among these types of technologies and how they work can help you decide which technology will work best for your application.

Photoelectric sensor

The photoelectric sensor has an emitter that sends out a light source. Then a receiver receives the light source. The common light source LED (Light Emitting Diodes), has three different types:

    • Visible light (usually red light) has the shortest wavelength, but allows for easy installment and alignment as the light can be seen.
    • Lasers are amplified beams that can deliver a large amount of energy over a distance into a small spot, allowing for precise measurement.
    • Infrared light is electromagnetic radiation with wavelengths longer than visible light, generally making them invisible to the humans. This allows for infrared to be used in harsher environments that contain particles in the air.

Along with three types of LEDs, are three models of photoelectric sensors:

    • The retro-reflective sensor model includes both an emitter and receiver in one unit and a reflector across from it. The emitter sends the light source to the reflector which then reflects the light back to the receiver. When an object comes between the reflector and the emitter, the light source cannot be reflected.
    • The through-beam sensor has an emitter and receiver in two separate units installed across from the emitter. When an object breaks the light beam, the receiver cannot receive the light source.
    • The diffuse sensor includes an emitter and receiver built into one unit. Rather than having a reflector installed across from it the light source is reflective off the object back to the receiver.

The most common application for photoelectric sensors is in detecting part presence or absence. Photoelectric sensors do not work well in environments that have dirt, dust, or vibration. They also do not perform well with detecting clear or shiny objects.

Ultrasonic sensor

The ultrasonic sensor has an emitter that sends a sound wave at a frequency higher than what a human can hear to the receiver.  The two modes of an ultrasonic sensor include:

    • Echo mode, also known as a diffused mode, has an emitter and receiver built into the same unit. The object detection works with this mode is that the emitter sends out the sound wave, the wave then bounces off the target and returns to the receiver. The distance of an object can be determined by timing how long it takes for the sound wave to bounce back to the receiver.
    • The second type of mode is the opposed mode. The opposed mode has the emitter and receiver as two separate units. Object detection for this mode works by the emitter will be set up across from the receiver and will be sending sound waves continuously and an object will be detected once it breaks the field, similarly to how photoelectric sensors work.

Common applications for ultrasonic sensors include liquid level detection, uneven surface level detection, and sensing clear or transparent objects. They can also be used as substitutes for applications that are not suitable for photoelectric sensors.

Ultrasonic sensors do not work well, however, in environments that have foam, vapors, and dust. The reason for this is that ultrasonic uses sound waves need a medium, such as air, to travel through. Particles or other obstructions in the air interfere with the sound waves being produced. Also, ultrasonic sensors do not work in vacuums which don’t contain air.

Radar detection

Radar is a system composed of a transmitter, a transmitting antenna, a receiving antenna, a receiver, and a processor. It works like a diffuse mode ultrasonic sensor. The transmitter sends out a wave, the wave echoes off an object, and the receiver receives the wave. Unlike a sound wave, the radar uses pulsed or continuous radio waves. These wavelengths are longer than infrared light and can determine the range, angle, and velocity of objects. radar also has a processor that determines the properties of the object.

Common applications for radar include speed and distance detection, aircraft detection, ship detection, spacecraft detection, and weather formations. Unlike ultrasonic sensors, radar can work in environments that contain foam, vapors, or dust. They can also be used in vacuums. Radio waves are a form of electromagnetic waves that do not require a transmission medium to travel. An application in which radar does not perform well is detecting dry powders and grains. These substances have low dielectric constants, which are usually non-conductive and have low amounts of moisture.

Choosing from an ultrasonic sensor, photoelectric sensor, or radar comes down to the technology being used. LEDs are great at detecting part presences and absence of various sizes. Sound waves are readily able to detect liquid levels, uneven surfaces, and part presence. Electromagnetic waves can be used in environments that include particles and other substances in the air. It also works in environments where air is not present at all. One technology is not better than the other; each has its strengths and its weaknesses. Where one cannot work, the others typically can.

Shedding Light on Different Types of Photoelectric Sensors

Photoelectric sensors have been around for more than 50 years and are used in everyday things – from garage door openers to highly automated assembly lines that produce the food we eat and the cars we drive.

The correct use of photoelectric sensors in a manufacturing process is important to ensure machines can perform their required actions. Over the years they have evolved into many different forms.

But, how do you know which is the right sensor for your application?  Let’s take a quick look at the different types and why you would choose one over another for your needs.

Diffuse sensors

    • Ideal for detecting contrast differences, depending on the surface, color, and material
    • Detects in Light-On or Dark-On mode, depending on the target
    • Economical and easy to mount and align, thanks to visible light beams
    • Shorter ranges as compared to retroreflective and through-beam sensors
    • IR (Infrared) light beams available for better detection in harsh environments
    • Laser light versions are available for more precise detection when needed
    • Mounting includes only one electrical device

Diffuse sensor with background suppression

    • Reliable object detection with various operating ranges, and independent of surface, color, and material
    • Detects objects against very similar backgrounds – even if they are very dark against a bright background
    • Almost constant scanning range even with different reflectance
    • Only one electrical device without reflectors or separate receivers
    • Good option if you cannot use a through-beam or retroreflective sensor
    • With red light or the laser red light that is ideally suited for detecting small parts

Retroreflective sensors

    • Simple alignment thanks to generous mounting tolerances
    • Large reflectors for longer ranges
    • Reliable detection, regardless of surface, color, and material
    • Polarized light filters are available to assist with detecting shiny objects
    • Mounting includes only one electrical device, plus a reflector
    • Most repeatable sensor for clear object detection; light passes through clear target 2X’s giving a greater change in light received by the sensor

Through-beam sensors

    • Ideal for positioning tasks, thanks to excellent reproducibility
    • Most reliable detection method for objects, especially on conveyor applications
    • Extremely resistant to contamination and suitable for harsh environments
    • Ideally suited for large operating ranges
    • Transmitter and receiver in separate housings

Fork sensors

    • Different light types (red light, infrared, laser)
    • Robust metal housing
    • Simple alignment to the object
    • High optical resolution and reproducibility
    • Fork widths in different sizes with standardized mounting holes
    • Identical mechanical and optical axes
    • The transmitter and receiver are firmly aligned to each other, yielding high process reliability

The next time you need to choose a photoelectric sensor for your manufacturing process, consider these features of each type to ensure the sensor is performing optimally in your application.

Using Guided Format Change to Improve Changeover and Productivity

Long before Covid, we were seeing an increase in the number of packaging SKUs. In 2019, Packaging Digest reported an estimated 42% increase in SKUs in the food and beverage industry.

Since Covid, there has been a further explosion of new packaging sizes, especially in the food and beverage marketplace. Food manufacturers have gotten very creative. Instead of raising prices due to the higher costs of goods, for example, they can reduce the size of product packages while keeping the consumer prices the same.

Many of today’s production machines are not equipped to changeover as quickly and as accurately to meet the demand of the marketplace. Manufacturers now face the challenge of “semi-automating” their existing machines, as opposed to procuring new machines or adding expensive motors to existing machines. One solution is to digitalize change points on existing machines.

Companies are looking to reduce the amount of time and the mistakes that occur when doing product changeovers. Allowing for operator guidance and position measurement can reduce your time and enhance your accuracy of those changeover events. Measurements are then tied to the recipe and the operator becomes the prime mover.

Guided Format Change

There are lots of technologies out there for helping with guided format change, such as automated position measurement, machine position, distance measurement, linear measurement, and digitalized rotary encoders.


As you are likely quite aware, there are often scales, marks, etc., written onto machines that don’t provide the greatest degree of accuracy. Introducing digitalized position and distance sensing can help you reduce time and limit errors during changeovers.

Change Part Identification

The other side of changeover is change part identification. Quite often during this process parts on the machine must be exchanged. Using the wrong change part can result in mistakes, waste, and delays, and can even damage existing machines.

Technologies, such as RFID, can help ensure the correct change part is chosen and added to the machine. During a recipe change, the operator can then validate that all the correct parts are installed before the startup of the next product run.

Guided format change is a cost-effective way to reduce changeover time and increase productivity either by retrofitting your existing machines or even new machines.

Sensor Mounting Made Easy

So, you’ve figured out the best way to detect the product shuttle paddle in your cartoning/packaging machine needs a visible red laser distance sensor. It’s taken some time to validate that this is the right sensor and it will be a reliable, long-term solution.

But then you realize there are some mechanical issues involved with the sensor’s placement and positioning that will require a bit of customization to mount it in the optimal location. Now things may have just become complicated. If you can’t design the additional mounting parts yourself, you’ll have to find someone who can. And then you have to deal with the fabrication side. This all takes time and more effort than just buying the sensor.

Or does it?

Off-the-shelf solutions

It doesn’t have to be that complex. There are possible off-the-self solutions you can consider that will make this critical step of providing a reliable mounting solution – possibly as straightforward as choosing the right sensor. Multiple companies offer sensor mounting systems that accommodate standard sensor brackets. Over the years, companies have continued to develop new mounting brackets for many of their sensor products, from photoelectric sensors and reflectors to proximity sensors to even RFID heads and linear transducers.

So it’s only natural to take that one step further and create a mounting apparatus and system that not only provides a mounting bracket, but also a stable platform that incorporates the device’s mounting bracket with things like stand-off posts, adjustable connection joints, and mounting bases. Such a flexible and extensive system can solve mounting challenges with parts you can purchase, instead of having to fabricate.

Imagine in the example above you need to mount the laser distance sensor off the machine’s base and offset it in a way that doesn’t interfere with the other moving parts of the cartoner. Think of these mounting systems and parts as a kind of Erector Set for sensing devices. You can piece together the required mounting bracket with a set of brace or extension rods and a mounting base that raises the sensor up and off the machine base and even angles it to allow for pointing at the target in the most optimal way.

The following are some mounting solutions for a variety of sensors:

These represent only a small number of different ways to mix and match sensor device brackets and mounting components to find a solid, reliable and off-the-shelf mounting solution for your next mounting challenge. So before considering the customization route, next time take a look at what might already be out there for vendors. It could make your life a lot simpler.

Choosing Sensors Suitable for Automation Welding Environments

Standard sensors and equipment won’t survive for very long in automated welding environments where high temperatures, flying sparks and weld spatter can quickly damage them. Here are some questions to consider when choosing the sensors that best fit such harsh conditions:

    • How close do you need to be to the part?
    • Can you use a photoelectric sensor from a distance?
    • What kind of heat are the sensors going to see?
    • Will the sensors be subject to weld large weld fields?
    • Will the sensors be subject to weld spatter?
    • Will the sensor interfere with the welding process?

Some solutions include using:

    • A PTFE weld spatter resistant and weld field immune sensor
    • A high-temperature sensor
    • A photoelectric diffuse sensor with a glass face for better resistance to weld spatter, while staying as far away as possible from the MIG welding application

Problem, solution

A recent customer was going through two sensors out of four every six hours. These sensors were subject to a lot of heat as they were part of the tooling that was holding the part being welded. So basically, it became a heat sink.

The best solution to this was to add water jackets to the tooling to help cool the area that was being welded. This is typically done in high-temperature welding applications or short cycle times that generate a lot of heat.

    • Solution 1 was to use a 160 Deg C temp sensor to see if the life span would last much longer.
    • Solution 2 was to use a plunger prob mount to get more distance from the weld area.

Using both solutions was the best solution. This increased the life to one week of running before it was necessary to replace the sensor. Still better than two every 6 hours.

Taking the above factors into consideration can make for a happy weld cell if time and care are put into the design of the system. It’s not always easy to get the right solution as some parts are so small or must be placed in tight areas. That’s why there are so many choices.

Following these guidelines will help significantly.

Capacitive, the Other Proximity Sensor

What is the first thing that comes to mind if someone says “proximity sensor?” My guess is the inductive sensor, and justly so because it is the most used sensor in automation today. There are other technologies that use the term proximity in describing the sensing mode, including diffuse or proximity photoelectric sensors that use the reflectivity of the object to change states and proximity mode of ultrasonic sensors that use high-frequency sound waves to detect objects. All these sensors detect objects that are in close proximity to the sensor without making physical contact. One of the most overlooked or forgotten proximity sensors on the market today is the capacitive sensor.

Capacitive sensors are suitable for solving numerous applications. These sensors can be used to detect objects, such as glass, wood, paper, plastic, or ceramic, regardless of material color, texture, or finish. The list goes on and on. Since capacitive sensors can detect virtually anything, they can detect levels of liquids including water, oil, glue, and so forth, and they can detect levels of solids like plastic granules, soap powder, sand, and just about anything else. Levels can be detected either directly, when the sensor touches the medium, or indirectly when it senses the medium through a non-metallic container wall.

Capacitive sensors overview

Like any other sensor, there are certain considerations to account for when applying capacitive, multipurpose sensors, including:

1 – Target

    • Capacitive sensors can detect virtually any material.
    • The target material’s dielectric constant determines the reduction factor of the sensor. Metal / Water > Wood > Plastic > Paper.
    • The target size must be equal to or larger than the sensor face.

2 – Sensing distance

    • The rated sensing distance, or what you see in a catalog, is based on a mild steel target that is the same size as the sensor face.
    • The effective sensing distance considers mounting, supply voltage, and temperature. It is adjusted by the integral potentiometer or other means.
    • Additional influences that affect the sensing distance are the sensor housing shape, sensor face size, and the mounting style of the sensor (flush, non-flush).

3 – Environment

    • Temperatures from 160 to 180°F require special considerations. The high-temperature version sensors should be used in applications above this value.
    • Wet or very humid applications can cause false positives if the dielectric strength of the target is low.
    • In most instances, dust or material buildup can be tuned out if the target dielectric is higher than the dust contamination.

4 – Mounting

    • Installing capacitive sensors is very similar to installing inductive sensors. Flush sensors can be installed flush to the surrounding material. The distance between the sensors is two times the diameter of the sensing distance.
    • Non-flush sensors must have a free area around the sensor at least one diameter of the sensor or the sensing distance.

5 – Connector

    • Quick disconnect – M8 or M12.
    • Potted cable.

6 – Sensor

    • The sensor sensing area or face must be smaller or equal to the target material.
    • Maximum sensing distance is measured on metal – reduction factor will influence all sensing distances.
    • Use flush versions to reduce the effects of the surrounding material. Some plastic sensors will have a reduced sensing range when embedded in metal. Use a flush stainless-steel body to get the full sensing range.

These are just a few things to keep in mind when applying capacitive sensors. There is not “a” capacitive sensor application – but there are many which can be solved cost-effectively and reliably with these sensors.