Ultrasonic Level Transmitter

SITRANS Probe LU is a 2-wire loop powered ultrasonic transmitter for level, volume and flow monitoring of liquids in open channels, storage vessels and simple process vessels. The SITRANS Probe LU is ideal for level monitoring in the water and wastewater industry and chemical storage vessels. The range of SITRANS Probe LU is 6 or 12 m (20 or 40 ft). 

Probe LU Catalog Specifications

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The Probe LU ultrasonic level transmitter provides unmatched reliability using Auto False-Echo Suppression for fixed obstruction avoidance, as well as an improved signal-to-noise ratio and improved accuracy of 0.15% of range or 6 mm (0.25"). SITRANS Probe LU includes Sonic Intelligence® signal processing from the field-proven Probe and incorporates new echo processing features and the latest micro-processor and communications technology. The Probe LU offers two communications options: HART or PROFIBUS PA (Profile version 3.0, Class B). The transducer on the Probe LU is available as ETFE or PVDF for harsh chemical conditions, as well as for applications with varying material and process temperatures. The Probe LU incorporates an internal temperature sensor to compensate for temperature changes.


Key Applications: chemical storage vessels, filter beds, liquid storage vessels.


Supplementary components are designed to work with most types of instrumentation to provide enhanced functionality such as remote displays and remote monitoring solutions. Please find more information here.


Don’t forget that the safest engineered level measurement solution includes switches for back-up, overfill, low level and dry run protection. Click here for more information.


  • Continuous level measurement up to 12 m (40 ft) range

  • Easy installation and simple start-up

  • Programming using infrared Intrinsically Safe handheld programmer, SIMATIC PDM or HART® Communicator

  • Communication using HART or PROFIBUS PA

  • ETFE or PVDF transducers for chemical compatibility

  • Patented Sonic Intelligence signal processing

  • Extremely high signal-to-noise ratio

  • Auto False-Echo Suppression for fixed obstruction avoidance

  • Level to volume or level to flow conversion


0.25 to 12 m (0.8 to 39 ft)
Process Temperature
-40 to 85 °C (-40 to 185 °F)

- 4 to 20 mA/HART


Wetted Parts
ETFE or PVDF transducers for chemical compatibility
0.15% of range or 6 mm (0.25")
Communications or Outputs



- EDD for SIMATIC PDM for remote configuration and diagnostics


Key Applications
Chemical storage vessels, filter beds, liquid storage vessels

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What precision and reliability mean for your applications

Your facility is a busy place - and materials and conditions inside your tanks/vessels/wells are always changing. Siemens ultrasonics selects the correct echo after every measurement, giving you stable readings while still allowing rapid response to actual changes in the material level. The result? Operations are more cost-effective. Inventory monitoring is always precise. Processes can be better controlled. And expensive spill cleanups can be avoided.

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