Level and Pressure Measurement

Series 36Xi W (CTD) High Precision Multi-Parameter Level Transmitter

Series XI W (CTD) Submersible Level Transmitter

The 36 Xi W series is built on the latest-generation microcontroller platform, which KELLER has developed to meet extremely high precision requirements and increase compatibility with a wide variety of interfaces. Along with pressure (level) information, digital interfaces also transmit other water parameters such as temperature and conductivity.

The 36 Xi W series is based on the proven KELLER 36 X W series using the high-quality 10 L-series pressure transducer. All series X pressure level transmitters feature an RS485 interface, which provide pressure and temperature standard, while versions requiring higher accuraty, temperature or conductivity sensor are available options. Multi-parameter probes fitted with pressure, temperature and conductivity sensors (CTD-conductivity, temperature, depth), are approximately 90 mm longer.


  • Pressure sensor: resolution 5 ppm
  • Mathematical compensation of nonlinearities and temperature dependencies
  • Sturdy stainless steel housing (titanium or Hastelloy also available)
  • Extended lightning protection fitted to the SDI-12 interface as standard
  • Level ranges from 0...3m to 0...300 m. Higher ranges possible with Sub-Conn connector
  • Ultra-high long-term stability
Pressure Ranges

Water column ca.
0,3...30 bar (rel.)
0,8...2 bar to 0,8...31 bar (abs.)
3...300 m
Measuring range Conductivity 0,2 / 2 / 20 / 200 mS/cm
Digital Interface RS485
Accuracy +/- 0,02 %FS max.
(0,3 bar Range: +/- 0,04 %FS)
Long-term stability, ranges > 1 bar
Long-term stability, ranges ≤ 1 bar
+/- 0,1 %FS max.
+/- 1 mbar max.

Download Datasheet

Download Keller BUS Protocol

Download SDI-12 Protocol

Link to Documents Library