Sensors Unleashed: A Guide to Choosing Ultrasonic, Radar or Submersible Tech for Level Monitoring!
- ellenex team
- Apr 19
- 11 min read
Step right into the thrilling realm of sensors, where an epic face-off awaits: Ultrasonic vs Radar vs Submersible sensors! Picture it as a clash of technological whoppers, and we’re your guides, injecting some excitement into the quest for the perfect sensor for your needs.
Theoretical Foundations of Level Measurement Modalities; Ultrasonic, Radar or Submersible?
The physical principles governing level measurement are categorized into non-contact and contact-based methodologies. Non-contact sensors, such as the Ellenex DU (Ultrasonic) and DR (Radar) series, utilize time-of-flight (ToF) principles to determine distance. Contact-based sensors, represented by the Ellenex PL (Submersible) series, rely on hydrostatic pressure measurements. Each modality interacts with the monitored environment through distinct physical phenomena, which dictates their performance in varying industrial and environmental contexts.
Ultrasonic Sensors: The Speedy Singers
How They Roll: Ultrasonic sensors are like the rockstars of the sensor world. Ultrasonic sensors work on the principle of emitting high-frequency sound waves (ultrasonic waves, faster than you can say “ultra-cool”) and measuring the time it takes for the sound waves to bounce back after hitting an object. This time measurement is then used to calculate the distance to the object.
Technical profile
Ultrasonic sensors operate by emitting high-frequency sound waves, typically ranging from 40 kHz to several hundred kHz, from a piezoelectric transducer. These mechanical waves travel through the air, reflect off the surface of the target medium, and return to the transducer. The sensor measures the time interval between transmission and reception, calculating distance using the speed of sound in air. While mathematically straightforward, the accuracy of ultrasonic sensing is inherently limited by the stability of the propagation medium. The speed of sound in air is approximately 331.3 m/s at 0 °C but varies significantly with temperature, humidity, and the chemical composition of the air. Temperature fluctuations can alter the speed of sound by approximately 0.17%/°C, necessitating integrated temperature sensors for real-time compensation. Furthermore, sound waves are susceptible to attenuation and scattering by air turbulence, dust, foam, and vapors, which often leads to signal degradation in complex industrial environments
The ultrasonic sensors market is projected to witness substantial growth, increasing from approximately USD 5,138.4 million in 2022 to around USD 13,241.8 million by 2030. The demand for ultrasonic sensors is expected to maintain a compound annual growth rate (CAGR) of 12% from 2022 to 2030.
Ellenex DU Series (Ultrasonic Sensors)
The DU series, including the DUS2, DUC2, DUS3, and DUC3 models, represents Ellenex’s entry-level solution for non-contact level monitoring. These sensors are designed for simplicity, cost-effectiveness, and low power consumption, making them a popular choice for standard water management and agricultural applications.
Advantages:
Cost effective: Are often more affordable than radar or submersible. They're budget-friendly, so your wallet won't break a sweat.
Non-contact: No touching required! These sensors are all about the non-contact vibes, as they do not require physical contact with the object being measured.
Suitable for many applications: Are widely used in applications such as parking assistance, liquid level measurements, and object detection.
Limitations:
Limited range: Are effective only within a certain range. Their range is a bit like your grandma's jokes (good, till she reaches her limit).
Affected by environmental conditions: Changes in temperature and humidity can affect the speed of sound, potentially impacting measurement accuracy.
Limited accuracy: In some cases, the sensors may have limited accuracy, especially in highly reflective or absorbent environments.
Radar Sensors: The Sky-High Heroes
How They Soar: Think of them as the James Bonds of the sensor world! Radar sensors use radio waves to detect objects and determine their distance and speed. These sensors emit radio waves and analyse the reflections to calculate distance and velocity.
Technical profile
Radar level sensors, particularly those in the Ellenex DR series, utilize electromagnetic waves in the microwave frequency spectrum. Unlike sound waves, electromagnetic waves do not require a physical medium for propagation and can even operate in a vacuum. Radar sensors generally utilize either pulsed signals or Frequency Modulated Continuous Wave (FMCW) technology. In FMCW radar, the sensor emits a continuous signal with a frequency that varies linearly over time. The reflection from the target surface is received and compared to the transmitted signal, creating a frequency difference directly proportional to the distance.
Ellenex DR Series ( Radar Sensor)
The technological leap in the DR series is defined by the shift to higher frequencies. While older radar systems operated at 6 GHz or 24 GHz, the DRC3 utilizes 80 GHz technology. Higher frequencies allow for a much narrower beam angle, often as focused as 3° to 4°. This narrow beam is critical for several reasons:
Confined Spaces: In narrow manholes, sewer pits, or small-bore tanks, a 3° beam can measure the liquid surface without interference from the side walls.
Internal Obstructions: Radar waves can bypass ladders, heating coils, and agitators that would otherwise confuse an ultrasonic sensor. This makes radar ideal for retrofit installations in complex vessels.
Signal Energy: By focusing the electromagnetic energy into a tighter beam, the sensor receives a stronger, more reliable return signal even from low-dielectric media like oils or turbulent surfaces.
Advantages:
Long range: Can operate over long distances, making them suitable for applications such as aircraft navigation and weather monitoring.
All-weather operation: Rain, fog, dust, nothing can rain on their parade. They are less affected by environmental factors, therefore thrive in all weather.
High accuracy: When it comes to precision, they hit the bullseye even with fast-moving objects. They provide precise distance and velocity measurements.
Limitations:
Cost: Are often more expensive than ultrasonic sensors, making them less practical for some applications.
Complexity: Requires more complex electronics and may need expert installation and calibration.
Size: Can be relatively large, which may limit their use in space-constrained applications.
Why DR Radar Overpowers DU Ultrasonic in non-contact sensor?
Environmental Factor | DU Series (Ultrasonic) | DR/DRC Series (Radar) | Radar Advantage |
Vapor/Steam | Fails or loses accuracy | Unaffected | High reliability in chemical tanks |
Surface Foam | Absorbs signal; "no echo" | Penetrates foam to liquid | Critical for wastewater basins |
Narrow Tanks | Wall reflections; false echo | Narrow beam avoids walls | Suitable for pipes and manholes |
Wind/Rain | Distorts/blows sound waves | Unaffected | Superior for outdoor flood monitoring |
Dead Zone | Significant (200-500 mm) | Minimal (50-100 mm) | Measures right up to the sensor |
Maintenance | Cleaning required regularly | Virtually maintenance-free | Reduced long-term labor costs |
Accuracy | ±5-10 mm | ±1-2 mm | Higher precision for billing/safety |
Submersible Sensors: The Liquid Legends
How They Dive In: Submersible sensors are designed to operate underwater or in liquid environments. They are used for measuring parameters such as water depth, temperature, and pressure. They're your go-to for underwater adventures!
Technical profile
The submersible level sensor, such as the Ellenex PLS2 and PLS3 models, operates on the principle of hydrostatic pressure. These sensors are placed at the bottom of a tank or reservoir, where they measure the pressure exerted by the column of liquid above them. To ensure accuracy, these sensors must account for atmospheric pressure changes. Ellenex PL series sensors typically utilize a gauge pressure reference, either through a vented cable or an integrated atmospheric pressure sensor, to isolate the pressure contributed solely by the liquid. This method is highly reliable for liquids with constant density but requires physical contact, making the sensor susceptible to fouling or chemical corrosion in aggressive media.
In recent years, the submersible sensors market has exhibited remarkable growth, surpassing the growth rates of both ultrasonic and radar sensors. This surge can be attributed to several factors, including heightened demand, technological advancements, and the effects of globalization. It is anticipated that the market will continue to expand, with a projected compound annual growth rate (CAGR) of 12.8% from 2023 to 2030.
Ellenex PL Series(Submersible Sensor)
For applications where non-contact sensing is not feasible, such as deep-well monitoring or underground storage tanks, the Ellenex PL series provides high-precision contact measurement through hydrostatic pressure. The PL series is categorized by its media compatibility and enclosure rating. The PLS2 is a standard submersible transmitter compatible with stainless steel (316L), making it ideal for water, diesel, and oil tanks. For more aggressive environments, the PLC3 is an IP68-rated, corrosion-resistant model designed for wastewater, acids, and mineral-rich liquids.
The PLS3 features a range of 1m to 200m H2O with an accuracy of ±0.25% span. A significant technical feature of the PL series is the inclusion of a built-in atmospheric pressure sensor, which eliminates the need for a traditional vented cable in some configurations. Vented cables are often the weakest point in submersible systems, as they can become clogged with moisture or dust; by utilizing a sealed gauge reference with an internal atmospheric sensor, Ellenex increases the long-term reliability of the device.
Advantages:
Waterproof: Are specifically designed to work in liquid environments and are waterproof by nature. It is the Aquaman of sensors.
Precision: 'Precision' is it's middle name, offers high precision and accuracy, especially for liquid-related measurements.
Diverse applications: Easy to find them in aquaculture, environmental monitoring, and underwater research.
Limitations:
Limited to liquid environments: They're not too keen on dry land—primarily meant for liquid environments.
Specialized use: Tools for specialized missions, and their use is limited to specific industries and applications. (Don't expect them to do your taxes).
Cost: Quality comes at a price, and these liquid legends can be a bit expensive (particularly for the high precision instruments).
Feature | DU Series (Ultrasonic) | DR Series (Radar) | Submersible (PL Series) |
Technology | Acoustic (Sound) | Electromagnetic | Hydrostatic Pressure |
Media | Liquids & Solids | Liquids, Solids, Slurries | Liquids |
Environment | Stable / Clean | Harsh / Volatile | Deep / Submerged |
Accuracy | ±0.25% to ±1% Span | ±1mm to ±2mm | ±0.25% Span |
Beam Angle | Wide (8°-12°) | Narrow (3°-4°) | N/A (Contact) |
Immunity | Affected by Temp/Vapor | Immune to Temp/Vapor | Affected by Density |
Maintenance | Regular cleaning | Virtually zero | Periodic cleaning |
The Grand Finale: Choosing Your Champion; Ultrasonic, Radar or Submersible?
Picking the right sensor depends on your specific application requirements. Here are some key considerations to help you make the right decision:
Range: How far do you need to measure? Ultrasonic rocks the short and medium, radar takes the long haul.
Environmental Conditions: Is your sensor facing tough conditions? Radar is your all-weather buddy, while submersible sensors thrive underwater.
Accuracy: If you need precision that could rival a surgeon's scalpel, radar and submersible sensors are your best pals.
Cost: Counting dollars? Ultrasonic is the thrifty choice, while radar and submersible sensors might make your wallet cry.
Size and Installation: Tight on space? Ultrasonic and submersible sensors are more space-friendly, while radar might need a bit more elbow room.
Measurement Techniques: Depends on your specific requirement. Important to note that submersible sensors are based on pressure measurements, whereas ultrasonic and radar are based on mechanical wave transmission.
For the sake of clarity and ease of comparison, following table can facilitate a more straightforward analysis. Moreover, the data presented in the table are derived from average statistics, and it is important to note that real-world scenarios can exhibit anomalies and variations.
Application | Best Sensor | Why? |
PLS2 (Submersible) | Standard, cost-effective solution for monitoring liquids compatible with stainless steel 316L (water, diesel, oil). | |
DRC3 (Radar) | Narrow 80 GHz beam bypasses wall reflections; immune to sewer gases and heavy condensation. | |
PLM2 (Submersible) | Ultra-narrow 15.8mm head fits into small boreholes where non-contact sensors cannot reach. | |
DRC3 (Radar) | FMCW technology penetrates thick surface foam and handles extreme turbulence that confuses other sensors. | |
DRC3 (Radar) | Non-contact measurement unaffected by steam, corrosive vapors, or vacuum/pressure changes. | |
PLS3 (Submersible) | IP68-rated for permanent immersion up to 200m; measures total hydrostatic pressure at the base. | |
DRC3 (Radar)/ PLS2 (Submersible) | Millimeter-level precision for high-value asset tracking; avoids contact with flammable fluids. Standard, cost-effective solution for monitoring liquids compatible with stainless steel 316L (water, diesel, oil). | |
DRC3 (Radar) | 3° beam angle focuses energy on the liquid surface, avoiding internal mixers and baffles. |
How can we, at Ellenex help you?
Our company is here to make your decision-making process a breeze. We specialize in helping you pinpoint the technology that best suits your specific requirements. Whether you're looking for ready-to-use sensors or require custom-designed solutions, we've got you covered. Your needs are our priority, so please don't hesitate to reach out and share your specifications with us. We're dedicated to tailoring our offerings to match your unique needs and ensure you get the perfect sensor solution for your gig.
So, there you have it, the choice between ultrasonic, radar, and submersible sensors ultimately depends on the unique requirements of your application, but important is we have all 3 choices for you (PL, DU and DR series of our products). It is generally more reasonable to consider that the technology does not compete but rather complements each other. You probably need a rest, after duking it out in this sensor showdown! No matter which one you choose, just remember to have fun with your sensor journey. Happy sensing folks!
Frequently Asked Questions
How do I choose between a non-contact sensor and a contact-based submersible sensor?
The choice primarily depends on the physical accessibility of the medium and the nature of the liquid being measured. Non-contact sensors, such as radar and ultrasonic devices, are ideal for applications where the liquid is corrosive, contains high levels of solids, or where hygiene is paramount, as the sensor never touches the material. These sensors are easier to install from the top of a vessel and require less frequent cleaning since they are not subject to fouling or chemical degradation.
On the other hand, submersible sensors are preferred for deep-water applications, such as groundwater wells, deep reservoirs, or underground tanks with limited overhead space. Because they measure hydrostatic pressure, they provide a very stable reading for liquids with constant density. However, they require direct immersion, meaning they must be constructed from materials compatible with the liquid and may need periodic maintenance if the environment contains debris or heavy sludge that could block the pressure-sensing diaphragm.
What makes 80GHz radar technology (DR Series) superior to traditional ultrasonic sensors in industrial environments?
80GHz radar technology is superior due to its reliance on electromagnetic waves rather than sound waves. Sound waves require a physical medium (air) to travel, which means their speed and accuracy are significantly altered by changes in air temperature, humidity, and pressure. Radar signals travel at the speed of light and are virtually unaffected by the atmosphere. This allows radar to maintain high precision even in the presence of steam, heavy vapor, or shifting air properties that would otherwise cripple an ultrasonic sensor's performance.
Additionally, high-frequency radar offers a much narrower beam angle. A focused 3° to 4° beam allows the sensor to pinpoint the target surface without interference from side walls, ladders, or agitators inside a tank. This "focus" ensures that the sensor only receives reflections from the intended target, whereas ultrasonic sensors with wider beam angles often suffer from "false echoes" reflected off internal obstructions or tank architecture.
Why is remote level monitoring considered a critical component of modern water infrastructure management?
Remote monitoring is critical for protecting public health and preventing environmental disasters like sewage overflows and floods. In urban environments, sewer systems and drainage networks must handle highly variable inflows, particularly during extreme weather events. Sensors provide real-time data that allows authorities to identify blockages or capacity issues before they lead to spills. This proactive approach is essential for complying with strict environmental regulations and avoiding the heavy fines associated with uncontrolled sewage discharge.
Furthermore, remote monitoring drastically reduces operational costs by eliminating the need for manual site inspections. Historically, checking the level of a remote reservoir or an underground sewer required sending a team into the field. With IoT-connected sensors, this data is transmitted wirelessly to a central dashboard, allowing for "management by exception." Utilities can then prioritize maintenance teams for locations that actually show signs of failure, extending the life of infrastructure assets and ensuring a more resilient water supply.
How do IoT connectivity protocols like LoRaWAN and NB-IoT enhance the value of industrial sensors?
IoT protocols like LoRaWAN and NB-IoT revolutionize sensor deployment by removing the physical and financial barriers of traditional wired systems. In many industrial or remote settings, the cost of running power and communication cables to a sensor can be ten times the price of the sensor itself. Low-power wide-area networks (LPWAN) allow sensors to operate on internal batteries for up to 10 years while transmitting data over several kilometers. This enables the widespread deployment of sensors in locations that were previously considered "unmonitored" due to cost or technical complexity.
Moreover, these protocols enable the seamless integration of data into advanced cloud platforms. Instead of just showing a raw number on a local display, IoT-connected sensors contribute to a broader digital twin of the entire operation. This allows for complex data processing, such as volume predictions, automated alarms for high/low thresholds, and historical trend analysis. By making data accessible from anywhere, these technologies empower decision-makers to optimize supply chains and improve disaster preparedness in real-time.
What are the primary maintenance considerations for different level sensing technologies?
Maintenance requirements vary significantly between technologies based on their interaction with the environment. Ultrasonic sensors are relatively low-maintenance but are sensitive to "build-up" on the transducer face. Condensation, dust, or spiderwebs on the lens can absorb or scatter sound waves, leading to signal loss. Regular inspection and wiping of the sensor face are often required in humid or dirty environments to ensure consistent performance.
Radar sensors, particularly high-frequency models, are largely maintenance-free. Because they use non-contact electromagnetic waves, they are immune to build-up, dirt, and condensation on the antenna. They do not require periodic recalibration for seasonal temperature changes, as their timing principle is independent of the atmosphere. Submersible sensors, being contact-based, require the most attention in harsh media. While they are highly durable, they may need periodic cleaning to prevent the build-up of fats, oils, or sludge on the sensing diaphragm, which can cause the reading to "drift" over time.
