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Well monitoring for a water supplier

The municipality company, in city of Luebek, Germany, provides potable water for approximately 120,000 households, all pumped from more than 30 wells.  These wells have water levels as deep as 160 meters.  The water levels of these groundwater wells must be measured with the highest possible accuracy.  

Previously, the pressure probe's analogue output signals (4…20mA) that had been used did not fulfill the required specifications and were replaced with OTT systems in 2014.  The OTT Pressure Level Sensor was chosen for accurate data and long term durability, as well as the OTT netDL 1000 datalogger, for a remote data transmission solution. 

Read a detailed description of the project here


Multichannel IP datalogger

OTT netDL Data Logger

Data loggers for remote data collection & long term monitoring

The versatile OTT netDL 500 and 1000 data loggers were developed specifically for use in hydrology and meteorology stations. In addition to recording data, the loggers are extremely low power and offer flexible data transfer options via the internet and mobile networks, providing a logging and telemetry solution for every project.

  • Ethernet USB-Host USB-Device RS-232 Satellite Cellular Industrial Communication
  • High data availability due to large memory and redundant communication, Multitasking capability for short polling cycles, Communication via TCP/IP, Integrated Web Server, Ultra low power consumption, Design for harsh environments, Industrial communication
  • Yes
  • SDI-12, RS-485 (SDI-12), Modbus RTU, analogue-in (voltage and current), Impulse Input, Status Input
OTT PLS - vented pressure transducer

OTT PLS - Pressure Level Sensor

Robust ceramic pressure transducer for water level measurement

The OTT PLS, SDI-12 or 4 ... 20 mA pressure probe, measures water level, depth to water, or pressure using an integrated controller and ceramic pressure-measuring cell.

  • Surface water Groundwater
  • Vented pressure cell
  • Water level, Pressure, Temperature
  • Water level and temperature measurement - for use with external data logger
  • 0 … 4, 10, 20, 40, and 100 m
  • ± 0.05% FS
  • No
  • SDI-12, RS-485 (using SDI-12), or 4 … 20 mA
  • A municipal utility company in Luebeck, Germany supplies approximately 35,000 m3 of water to about 120,000 households each day.
  • This company has been supplying the water for the area since 1867. 
  • The drinking water for the city is pumped from the three groundwater works: Kleinensee, Klein Disnack and Vorwerk, which combined have more than 30 wells, which are up to 160m deep each.
  • Water level in the wells is supposed to be measured with the highest possible accuracy, but the previous pressure probes used did not fulfill requirements. They were replaced with OTT Hydromet technology (OTT PLS and OTT netDL 1000) 
  • 24 wells were equipped with the digital pressure probe OTT PLS (RS485 measuring range: 0...40m) with ceramic pressure cells. The robust instruments provide accuracy of +/- 2 cm (0.05% FS) with a measuring range of 0-40 meters.
  • The OTT PLS probes are connected via RS485 to the station manager and data logger OTT netDL 1000.
  • The data loggers are connected via Profinet to the existing SPS and thus the measured data can be transmitted from end to end -from the sensor into the electronic operating log (OTT PLS – OTT netDL 1000 – SPS – ACRON).
  • The OTT netDL1000 units are connected via Ethernet to the network of the waterworks of Luebeck and can be configurated via LAN.
  • The web server of the OTT data logger provides a platform where data can be accessed and visualized, 


  • The long term digital measurement chain, from measurement to data storage, guarantees the highest possible accuracy, even for large measurement ranges because conversion from analogue to digital is not required.
  • State-of-the-art IP data loggers and station managers OTT netDL1000 allow for smooth integration into existing structures via standardized interfaces and protocols.
  • Precise digital pressure probes (OTT PLS) with robust ceramic-capacitive pressure cells allow for continuous operation with minimal maintenance requirements and accurate, long term measurements.
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