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Inline sound velocity sensor:

  • Concentration measurement, interface detection, and product identification
  • For use in hazardous environments, i.e. chemical industry, and hygiene applications in the beverage and pharma industries
  • Available in e.g. SST, Hastelloy BC1, rhodium plating, and more
  • Easy integration, no maintenance, no consumables required

L-Sonic tells a story: a 30-year story of sound velocity sensor development at Anton Paar, culminating in the sleek L-Sonic 5100/6100 series, which delivers pin-point accuracy and constant quality control. The L-Sonic 5100 has a fork-type senor, the L-Sonic 6100 a tube-type sensor. Use them for inline concentration measurements, interface detection, or product identification. And rest assured: the sensors continuously monitor the product quality of liquids during production. 

Key features

L-Sonic: compact, stand-alone, supremely accurate

L-Sonic: compact, stand-alone, supremely accurate

The L-Sonic series’ digital signal processing produces remarkable repeatability of 0.005 m/s (fork type). And a temperature-compensated crystal oscillator provides a measurement time basis of phenomenal exactitude.

  • Measurements uninfluenced by changes in pressure, flow rate, and viscosity
  • High tolerance to bubbles
  • Applicable for interface detection or product identification (fork-type sensor)
  • Ideal for OCR measurement (tube-type sensor)
The right instrument for demanding applications and hazardous environments

The right instrument for demanding applications and hazardous environments

The L-Sonic sensors can be applied to a wide range of samples and are resistant to aggressive media because their wetted parts (L-Sonic 5100) comprise a variety of different materials. The sensor is suited to hazardous environments, including those where there is a risk of explosion, and to demanding hygiene applications in the beverage and pharmaceutical industries. L-Sonic’s modularity means easy and cost-efficient integration. The tube-type sensor L-Sonic 6100 can be directly installed in small pipes, so the entire flow passes through the sensor, and the fork-type sensor L-Sonic 5100 is ideal for insertion into large pipes or tanks. Anton Paar’s L-Sonic is versatile and resilient. Its solutions are comprehensive and customized across industry:

  • Hazardous environments (e.g. chemical industry)
  • Hygiene applications (e.g. beverages, pharma, automotive)
  • Full flow, inline, bypass, or tank installation
Save time: quick installation and start-up; no maintenance needed

Save time: quick installation and start-up; no maintenance needed

With these sensors, you’ll save a ton of time. Pre-configured and adjusted in the factory, they come with the right setup and integrated application formulas – installation, start-up, and commissioning are quick, no on-site adjustments, maintenance, or consumables are needed. 

An Anton Paar measuring solution – tailored to your specific needs

An Anton Paar measuring solution – tailored to your specific needs

Anton Paar draws from our comprehensive database and application know-how to give you the information you need to measure the concentration of your liquids precisely. In our in-house laboratory we measure your samples and develop the formula best suited to your needs. We identify the ideal measuring method (density, sound velocity, or refractive index) for your sample, as well as the perfect concentration and temperature range.

No matter which industry you’re in, we help you determine the concentration of liquids accurately and efficiently. L-Sonic is the right choice for the chemicals, beverages, and petroleum sectors, and more.

Technical specifications

L-Sonic 5100 L-Sonic 6100
Measuring range 800 m/s to 2500 m/s 200 m/s to 1560 m/s
Material of the wetted parts Stainless Steel 1.4404 (316L)
Monel 400

Fork length:
56 mm
125 mm
Stainless Steel 1.4404 (316L)
Accuracy in adjusted range:
Reproducability sound velocity0.1 m/s
Reproducability temperature0.02 °C
Repeatability 0.005 m/s0.01 m/s
Process temperature -25 °C to 125 °C
CIP/SIP temperature and duration 145 °C for max. 30 min.
Ambient temperature
(for non-Ex versions)
-25 °C to 65 °C without HMI
-20 °C to 55 °C with HMI
Process pressure absolute According to flange
up to 70 bar @ 125 °C or
100 bar @ 50 °C
Recommended flow rate 0.5 to 6 m/s50 to 700 L/h
Communication Pico 3000:
  • Analog
  • HART
  • Modbus RTU

mPDS 5:
  • Devicenet
  • Ethernet/IP
  • Modbus TCP
  • I/O Board
Process connections VARIVENT® N
DIN 11851
EN 1092-1
ANSI B16.5
Tube end:
OD 12 mm
Non-Ex version (L x W x H)
Ex version (L x W x H)

Depending on model
Depending on model

150 mm x 145 mm x 175 mm
160 mm x 160 mm x 190 mm

Explosion-proof versions according to ATEX / IECEx / FM / UL / CSA

Anton Paar Certified Service

The Anton Paar quality in service and support:
  • More than 350 manufacturer-certified technical experts worldwide
  • Qualified support in your local language
  • Protection for your investment throughout its lifecycle
  • 3-year warranty
Learn more


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Not all items are purchasable online in specific countries.

To find out if you can purchase online from your location, check the online availability below.

Online price only | excl.incl. 0VAT


Compatible with:
L-Sonic 5100 | 6100
Delivery time: %1$s – %2$s working days %1$s – %2$s weeks %1$s – %2$s months
Part number: 74911