More than sensors+automation

JUMO MAERA S28 - Level Probe (404392)


  • Level probe for continuous level measurement in liquids
  • Measuring ranges: 250 mbar to 10 bar (2.5 to 100 mWS)
  • Medium temperature: 0 to 50 °C
  • Piezoresistive silicon sensor
  • Accuracy: 0.3 % MSP (linearity)
  • Excellent long-term stability
  • High overload resistance
  • Integrated overvoltage protection
  • Reverse-polarity protection
  • Integrated temperature sensor Pt100 also available
  • Suitable for indoor and outdoor installations

Customer benefits

  • Process reliability

The core of the level probe is a piezoresistive measuring cell, which features high overload resistance and which is particularly stable in the long term, reliable, and temperature resistant. An integrated overvoltage protection prevents the effects of lightning that could lead to destruction of the level probe. Maximum security during startup is guaranteed by a reverse polarity protection that protects the measuring device against damages.

  • Versatile

The simultaneous measurement of level and temperature can also be achieved with a Pt100 temperature sensor. Costs are minimized as a result of very simple installation and startup. An optimized variant of the level probe is available for use in "deep wells".


Level and level measurement

  • In water and wastewater management
  • In hydroelectric power stations
  • In well and surface water

Product comparison level probes


The JUMO MAERA S28 level probe is used for the continuous hydrostatic level measurement in liquids. Filling heights between 2.50 and 100 mWS (water column) can be achieved in ventilated tanks.

When the level probe is immersed into a liquid, a liquid column emerges above the probe. The liquid column increases as the probe is immersed deeper into the liquid and creates a hydrostatic pressure on the measuring system by the force of its weight. The measured pressure is transmitted as a standard signal. The signal is linearly proportional to the rising liquid column.

The surrounding pressure is achieved through a special cable with an integrated pressure equalization hose. Any variations in air pressure are therefore automatically compensated and the surrounding pressure is taken into account. The installation can be performed in both indoor and outdoor areas.

The level probe is equipped as standard with an integrated overvoltage protection, which protects the level probe against damage in the event of lightning strikes in surrounding water. With regard to the temperature-dependent density of a liquid, the medium temperature can be recorded with an integrated temperature sensor Pt100 during level measurement. This temperature value can then be used for compensation.


Further information on our level probes from the JUMO MAERA series can be found in the brochure "Level Probes – Hydrostatic Level and Filling Level Measurement" in the Documentation category.

Further technical information is available in the Documentation category.


Accessory articles

Article number Product description Price / piece
Terminal box with pressure compensation price on request

(in stock)

Cable holder price on request

(in stock)

Sealing screw price on request
Pressure equalization filter for cable price on request

(in stock)