Pressure transducer with integrated logger


The OTT PLS measures water level, depth of water, or pressure by means of an integrated controller and ceramic pressure-measuring cell. Design features such as multiple communication outputs (SDI-12 or 4-20 mA), stainless steel housing, and a rugged cable make this sensor ideal for monitoring water level in a variety of applications.


  • The robust ceramic pressure cell offers industry-leading accuracy and does not deform over time like membrane technology, providing long-term measurement stability
  • Rugged design: Ceramic pressure cell resistant to physical force (5 x burst pressure) and enclosure made of high-quality saltwater resistant steel for use in coastal environments
  • Built-in microcontroller–compensates for temperature effects and applies correction values for gravitational acceleration and water density
  • Vented pressure probe, automatically compensates for changes in barometric pressure
  • Robust cable with Kevlar core for length stabilization and capillary tube for venting
  • Simple setup and connection to external dataloggers using SDI-12 or 4-20 mA interfaces
  • Optimized resolution is achieved by assigning the 4-20 mA to that part of the measuring range that is actually required
  • Water temperature output in addition to water level (for SDI-12 output)

What's the Easiest and Quickest Way to Start Collecting Data and Access it Anywhere?

The Answer's in the Cloud.

eTracker is a cellular modem and "virtual" cloud-based data logger in one (meaning you don't need to install a separate data logger). Simply connect your sensor and a power source to eTracker and you're done. Configure (or reconfigure) anytime from any Internet-connected device, and use Stevens-Connect to retrieve your data, or forward it to your favorite software system.

Technical Specifications

Waterlevel measurement

Measuring ranges

0-4 m, 10 m, 20 m, 40 m, 100 m

Accuracy, pressure sensor

SDI-12: ±0.05 % FS (linearity and hysteresis)
4-20 mA: ±0.1 % FS (linearity and hysteresis), 10 ppm/°C at 20 °C

Resolution (SDI-12)

0.001 m; 0.1 cm; 0.01 ft; 0.1 mbar; 0.001 psi

Temperature compensated working range

-5 °C to +45 °C (ice-free)

Temperature measurement

Measuring ranges

-25 °C to +70 °C (ice-free)

Accuracy, temperature

±0.5 °C / ±0.9 °F

Resolution, temperature

0.1 °C / 0.1 °F


Available interfaces

4-20 mA, SDI-12, RS485 (via SDI-12 protocol)

Supply voltage

+9.6 to +28 VDC, typically 12/24 VDC

Power consumption (SDI-12)


<600 µA


<3.6 mA

Pressure sensor

(capacitive pressure sensor) ceramic, temperature compensated, overload safe for up to 5 times the measuring range without permanent mechanical damage

Temperature sensor




195 mm x 22 mm


approx. 0.3 kg


Housing: stainless steel 1.4539 (904L) resistant to sea water
Seals: Viton Cable jacket: PUR

Protection type


Mechanical strength

meets the mechanical shock tests of IEC 68-2-32

Environmental conditions

Operating temperature

-25 °C to +70 °C

Storage temperature

-40 °C to +85 °C