Level and Pressure Measurement

Series 33XEi / 35XEi / 36XWEi High Precision Intrinsically Safe Pressure Transmitters

Series 33XEi / 35XEi / 36XWEi High Precision Intrinsically Safe Pressure Transmitters

These piezoresistive pressure transmitters are approved for use in high explosive gas and dust atmospheres of groups I (mining industry) and II (industrial applications) where there is a high risk of explosion. Optionally available are Low Voltage Versions (LV) with 3.5…8.5 V.

Signal Processing:
This series features microcontroller-based electronic evaluation to ensure maximum accuracy. Each transmitter is gauged across the entire pressure and temperature range. This measurement data is used to calculate a mathematical model that enables correction of all reproducible errors. In this way, KELLER can guarantee high accuracy as an error band within the overall compensated pressure and temperature range. Two compensated temperature ranges are available for industrial transmitters, according to choice: -10…80 °C and 10…40 °C. The level probes are gauged in the 0…50 °C temperature range only. The calculated pressure value can be read via the interface, and is simultaneously processed as an analog signal.

The interface is designed as a robust RS485 half-duplex for 9'600 and 115'200 baud. It can be used to implement bus systems with 128 subscribers and line lengths of up to 1400 m. There is an external lead-through for the interface on all products except the version with the DIN 43650 plug.


  • Low Voltage Version labelled with “LV” in Type Designation
  • Mining Version labelled with “M” in Type Designation
  • Dust approval 
Pressure Ranges 1...1000 bar (see data sheet)
Output RS 485
4...20 mA, 2 wire
0...10 V, 3 wire
Accuracy / Precision (see data sheet)
Stability, Range > 1 bar
Stability, Range < 1 bar
0,1 %FS
1 mbar

Download Series Datasheet

Download Series 33XEi / 35XEi / 36XWEi Manual

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