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What is a Capacitive Probe Sensor?

Tank monitors are rapidly becoming a common technology purchase around the world. The data these devices collect can greatly impact business operations, from logistics to customer service. 

However, in order to achieve this kind of result, your tank monitors must be equipped with the most precise and efficient monitoring tools. A variety of technologies are available for tank monitoring, and capacitive probe sensing is quickly becoming a frontrunner. 

This article will explain the basis of capacitive probe sensing, illustrate the benefits of this technology and showcase some common use cases.

What is Capacitive Probe Sensing?

Capacitive probes determine liquid levels by using the dielectric constant of the fluid. The probe is essentially two parallel pieces of metal placed vertically in a tank. A small electric charge is then applied to these pieces. As the level of fluid between the pieces rises and the amount of air between the pieces decreases, an electrical property called capacitance changes. This change can be sensed with extreme accuracy. The capacitance values are then converted into a percentage based on how the probe is configured.

Otodata capacitance probes have an integrated Bluetooth transmitter. This transmitter wirelessly sends the fill-level to a nearby tank monitor, which sends the reading to the internet. A single tank monitor can listen to multiple capacitance probes.

Why Should You Use Capacitive Probe Sensing?

Capacitive probe sensing technology is a true set it and forget monitoring tool. Here are the main reasons why these probes are so popular: 


Since capacitive probes have no moving parts, their measurements are extremely accurate. For example, a typical float-based tank monitor is accurate within 5%. A capacitive probe, in contrast, can be accurate within 1% and sometimes even as precise as 0.1%. Additionally, capacitance probes maintain that level of accuracy over the entire span of the tank, while mechanical float gauges tend to lose accuracy once they fall below 20%.  This means you can run customers lower without risking a runout due to inaccurate readings. The lack of moving parts also means false readings from stuck floats are now a thing of the past.

Low maintenance

This type of monitoring technology requires virtually no maintenance and has a long 10-year battery life. Since the probe has no moving parts, nothing can break or malfunction over time like other types of level sensors. 


These probes can be made in a variety of sizes to accommodate all kinds of tanks. It can perform especially well in narrow tanks that were difficult to monitor with the previously available technologies.

Applications of Capacitive Probe Sensing Technology

Since this technology can be used to measure a wide variety of products, it can be found in many industries. Here are some of the most common applications of this technology. 


Capacitance probes are having a big impact on how propane tanks are monitored. Their level of accuracy allows propane marketers to make far more efficient delivery trips and eliminate uncertainty about the accuracy of level readings. They are also opening a completely new opportunity to monitor smaller propane vessels like 100lb (45kg) cylinders where a traditional float gauge wasn’t feasible.

Oils and Lubricants

Capacitance probes are ideal for monitoring oils and lubricants. Many customers in this industry don’t have the exact internal dimensions of their tanks, making selecting the right sensor-length difficult. With capacitance probes for oils and lubricants, customers will be able to order a single standard size for all of their tanks and then trim the probe to a custom length on-site.

Industrial Gas

Capacitance probes have rapidly become standard issue with some of the largest industrial gas tank manufacturers, and for good reason. They aren’t subject to blown sensor diaphragms like differential pressure sensors, and they withstand frequent movement on trucks better than float gauges. Add in the fact that industrial gas tanks are often present in pairs, and the ability to monitor multiple tanks from the same device becomes very powerful.

Is Capacitive Probe Sensing Right For You?

Capacitance probes are gaining popularity because they answer tank monitors' most common pain points. Their ease of use, superior accuracy, and increased reliability are quickly making this technology a must. Add in the ability to monitor multiple tanks from one monitor, and you have a breakthrough in tank monitoring.

Contact us today to discuss adding this technology to your tanks and retrofitting your existing ones.



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