LM210 Radar Liquid Level Sensor

Product Overview

The LM210 series is an intelligent liquid level measurement instrument based on high-frequency millimeter-wave radar technology, specifically designed for industrial storage tanks, reactors, water tanks, etc. The product adopts a non-contact measurement principle. It emits high-frequency electromagnetic waves and receives the reflected echoes from the surface of liquid/solid media. The real-time analysis and calculation are performed by the rear high-speed processing circuit, converting the liquid level value into standard industrial signals (switching, analog current/voltage) and outputting them. The liquid level is displayed on the high-definition color LCD screen on-site.

This series of instruments have a measurement range of 500...30000mm (with a top blind zone of only 50mm), and the accuracy is up to ±2mm. It can be widely applied in the monitoring of liquid and solid powder liquid levels in industries such as chemical engineering, water treatment, food and beverage, and energy. The housing and probe rod are made of stainless steel 304 (with a PTFE anti-corrosion layer on the outer surface of the probe rod), with a protection level of IP67, and are suitable for harsh industrial environments.

Working principle

Signal transmission: The millimeter-wave radar module embedded in the sensor emits continuous high-frequency electromagnetic waves with a linearly changing frequency over time (typically operating at 80 GHz), with an extremely narrow beam angle and concentrated energy.

Signal reflection: The electromagnetic waves are reflected when they encounter the surface of the measured medium (liquid or solid), and some of the energy returns along the original path to the sensor.

Signal reception and mixing: The receiving antenna captures the reflected echoes and mixes them with the transmitted signal to obtain a intermediate frequency signal. The frequency of this signal is proportional to the difference in frequencies between the transmitted signal and the reflected signal, and this frequency difference directly reflects the flight time of the electromagnetic wave from transmission to reception.

Distance calculation: The built-in high-speed DSP processor performs a fast Fourier transform (FFT) on the intermediate frequency signal to accurately extract the frequency difference and combine it with the speed of light to calculate the distance from the sensor to the medium surface.

Output and display: The processed liquid level data is displayed in real time on a high-definition color LCD screen (supporting numerical values, bar graphs, and status color indicators), and is also converted by the signal processing circuit into user-selectable industrial standard signals (PNP/NPN switch quantities, 0... 20mA/4… 20mA current, 0... 5V/1… The 5V voltage is output to the PLC, DCS or alarm device.

Technical advantages: The 80GHz millimeter wave has the characteristics of short wavelength, concentrated energy and strong penetration power. It can effectively penetrate the dust, steam and foam inside the tank, and is not affected by changes in medium density, temperature and pressure. It is especially suitable for liquid level measurement in small range, narrow installation space and complex working conditions.

Product features

High-precision measurement

Accuracy ±2mm, linearity ≤ ±1.5% of the range, blind zone only 50mm, meeting strict control requirements.

Multiple signal outputs, strong compatibility

Switch: PNP/NPN selectable, open/closed configurable, current < 500mA, can directly drive relays.

Analog: 3-wire 0... 20mA/4… 20mA current (load ≤ 500Ω) and 0... 5V/1… 5V voltage (load > 10kΩ), compatible with various PLCs.

Protection: Built-in reverse phase, overload, and short circuit protection, ensuring safe wiring.

Industrial-grade protection and durable materials

Shell made of stainless steel 304, probe sleeve coated with PTFE for anti-corrosion, resistant to acid and alkali corrosion.

Protection IP67, dustproof and waterproof, working temperature -20...80℃ (medium at the same temperature), suitable for harsh environments.

Intelligent display and interaction

High-definition color LCD screen, real-time display of liquid level, percentage, echo intensity and status (green/yellow/red), inspection is clear at a glance.

No need to open the cover for debugging, parameters can be set through screen buttons to ensure protection reliability.

Low power consumption and easy installation

24V power supply, no-load current ≤ 30mA, energy-saving and efficient.

Outlet method is flexible: M12×1 connector or direct wiring, installation and maintenance are convenient.

Non-contact measurement, no maintenance required

Radar wave non-contact, no moving parts, not affected by medium adhesion and corrosion, long-term stable and reliable, significantly reducing maintenance costs.

Product parameters

Product Application

1. Chemical Industry

Application scenarios: Acid-base storage tanks, organic solvent storage tanks, reaction vessels, intermediate storage silos.

Applicability analysis:

Corrosion resistance requirement: The probe is coated with PTFE anti-corrosion layer, which can withstand strong acid and strong alkali corrosion.

Precision requirement: ±2mm high precision, meeting the strict requirements for precise chemical ingredient ratio control.

Non-contact advantage: Avoiding direct contact of the sensor with corrosive media, extending service life.

2. Water Treatment Industry

Application scenarios: Clear water tanks, sewage tanks, sedimentation tanks, collection wells, dosing tanks.

Applicability analysis:

Wide range coverage: Maximum 30-meter range, suitable for deep wells or large water tanks.

Small blind zone: Top blind zone is only 50mm, can be installed on the top of space-constrained tanks.

Anti-interference: High-frequency millimeter wave is not affected by water vapor, foam and temperature stratification, measurement is stable.

3. Food and Beverage Industry

Application scenarios: Liquid food storage tanks (milk, edible oil, juice), fermentation tanks, syrup tanks, powder storage silos (flour, starch).

Applicability analysis:

Hygiene requirement: Stainless steel material meets food-grade contact standards, smooth surface for easy cleaning.

Medium compatibility: PTFE anti-corrosion layer can withstand acid and alkali components in food (such as cleaning with citric acid).

Multiple output options: Supports voltage/current output, facilitating integration into food factories' automation control systems.

4. Energy Industry

Application scenarios: Oil storage tanks (crude oil, diesel), lubricating oil tanks, power plant water treatment systems, cooling tower water tanks.

Applicability analysis:

Explosion-proof potential: (Note: The parameter does not clearly specify the explosion-proof level. If there is an actual explosion-proof design, it is more applicable.) Suitable for flammable environments such as oil products.

Stability: Not affected by changes in the dielectric constant of the medium, even when oil stratifies or contains water, accurate measurement can be achieved.

Weather resistance: IP67 protection, -20~80℃ wide temperature range, suitable for harsh climates of outdoor storage tanks.

5. Other Industrial Fields

Pharmaceutical Industry: Liquid level control of reaction vessels, solvent recovery tank monitoring.

Building Materials/Metallurgy: Material level monitoring of solid powders (such as cement, mineral powder, plastic particles) (Note: The product is suitable for solids, but it is necessary to confirm the repose angle of the powder and the impact of dust on the antenna. This product has strong penetration of high-frequency radar waves for dust).

Paper Industry: Black liquor tank, white water tank, pulping tower liquid level measurement.