Drexelbrook Usonic Series Ultrasonic Level Transmitter

Overview

The Drexelbrook Usonic Series Ultrasonic Level Transmitter is an industrial-grade non-contact level measurement instrument engineered for reliable, maintenance-free operation in demanding process environments. It operates on the pulse-echo time-of-flight principle: a transducer emits high-frequency ultrasonic pulses (typically 50 kHz) toward the surface of the measured medium; the elapsed time between emission and echo return is precisely measured and converted into distance using the speed of sound in air—temperature-compensated via an integrated sensor. This fundamental physics-based methodology ensures stable performance across varying ambient conditions, provided vapor composition and temperature gradients remain within operational limits. Designed specifically for continuous level monitoring in tanks, sumps, wet wells, and open-channel flow structures (e.g., flumes and weirs), the Usonic Series delivers consistent accuracy without physical contact with the process medium—eliminating concerns related to corrosion, fouling, or pressure compatibility.

Key Features

• Patented adaptive signal processing algorithm that dynamically suppresses false echoes caused by tank walls, internal structures, agitators, or piping—enabling robust operation in geometrically complex vessels.
• Narrow 5° acoustic beam angle minimizes side-lobe interference and improves targeting resolution, especially critical in narrow ducts or confined installations.
• Dual-transducer configuration option supports differential level measurement applications—such as water level drop across weirs or Parshall flumes—enabling direct open-channel flow calculation per ISO 4359 and ASTM D1941 standards.
• Integrated temperature sensor enables real-time speed-of-sound correction, maintaining measurement stability across ambient temperatures from –20 °C to +60 °C.
• IP67-rated housing with UV-stabilized PTFE-coated transducer face ensures long-term durability in outdoor, washdown, and chemically aggressive environments.
• Configurable analog output (4–20 mA, HART® v7 compatible) and digital communication (RS-485 Modbus RTU) support seamless integration into DCS, SCADA, and PLC-based control systems.

Sample Compatibility & Compliance

The Usonic Series is suitable for liquid level measurement in water, wastewater, slurries, and non-volatile chemical solutions where surface acoustics permit consistent echo return. It is not recommended for highly turbulent, foaming, or vapor-laden surfaces, nor for media with strong ultrasonic absorption (e.g., heavy oil mist or fine particulate aerosols). The device complies with electromagnetic compatibility requirements per IEC 61326-1 (industrial environment) and meets RoHS Directive 2011/65/EU. Its analog output and configuration interface adhere to NAMUR NE43 fault signaling conventions. While not intrinsically safe certified, it may be deployed in Zone 2/Class I Div 2 areas when installed with appropriate barriers or isolators per IEC 60079-11 and UL 913.

Software & Data Management

Configuration and diagnostics are performed via Drexelbrook’s proprietary PC-based Usonic Configurator software (Windows-compatible), which provides guided setup workflows, live echo curve visualization, and automatic calibration validation. All configuration parameters—including damping, blanking distance, temperature compensation offset, and flow coefficient tables—are stored with timestamped audit trails. The software supports export of configuration files for version control and facilitates batch deployment across multi-unit installations. When integrated with supervisory systems supporting HART® v7, full device diagnostic data—including transducer health status, signal strength metrics, and temperature drift logs—is accessible for predictive maintenance planning. The system architecture supports traceability requirements aligned with GLP and GMP documentation practices.

Applications

• Continuous level monitoring in municipal and industrial wastewater treatment plants (primary clarifiers, aeration basins, effluent channels).
• Open-channel flow measurement in Parshall, Palmer-Bowlus, and Palmer flumes under ISO 1438-1 and ISO 4359 compliance frameworks.
• Pump control logic in lift stations and stormwater retention basins using level-triggered start/stop thresholds.
• Inventory management in aboveground storage tanks containing potable water, reclaimed water, or non-hazardous process liquids.
• Interface level detection in dual-layer liquid systems where upper-phase density permits sufficient acoustic impedance contrast (e.g., oil/water separation tanks).

FAQ

Is the Usonic Series suitable for measuring level in pressurized vessels?
No. As a non-contact air-coupled ultrasonic device, it requires an atmospheric or vented headspace and cannot operate inside sealed, pressurized, or vacuum environments.
Can it measure through foam or heavy vapor layers?
Foam and dense vapor significantly attenuate ultrasonic energy; sustained foam layers >5 cm thick or persistent condensate curtains will impair echo return and reduce measurement reliability.
What is the minimum measurable distance (blanking distance)?
The standard blanking distance is 0.15 m, configurable down to 0.10 m depending on transducer model and environmental noise conditions.
Does the device require periodic recalibration?
No field recalibration is required under normal operating conditions; however, annual verification against a known reference level (e.g., sight glass or calibrated tape) is recommended for QA/QC compliance.
Is Modbus TCP supported?
The standard communication interface is RS-485 Modbus RTU; Modbus TCP is not natively supported but may be enabled via external protocol gateway hardware.