Why all analog sensors have a DC output

The gas analyzer is used to measure gas concentrations of the oxygen concentration in industrial, laboratory and protective gases as well as in the process of mixing

Areas of application

When measuring oxygen concentrations, the device can be used, for example, in breweries to measure the oxygen concentration in carbon dioxide. Here the application ranges from the control of the delivered gases to the monitoring of the pre-stressing gases in the tank and filler area.


Measuring principle

The protective gas measuring device contains a sensor that uses the oxide ion conductivity of ceramic made of zirconium dioxide with stabilizing additives. The oxide ion conductivity of zirconium dioxide increases exponentially with temperature and reaches sufficiently high values ​​above 600 ° C. The ceramic oxide ion conductor is used as a ceramic body along which a gas to be measured is passed. The ceramic body is axially symmetrical in a thermally well insulated electric furnace. The electrodes of the galvanic measuring cell are made of platinum. The electrode on the outside of the pipe, surrounded by dry air, serves as a reference electrode with a constant, known electrode potential.

Technical specifications

Measurement data

Measuring range0 ··· 1.0 vol.ppm O2 (0 ··· 20.6 vol .-%)
(Display 1 vol.% To 20.6 vol.% Shown exponentially)
Measurement accuracy at normal pressure ....rel. Measurement error <5%
Sample gas throughput5 ... 10 l / h (when using the
internal pump automatically regulated)
Max. Permissible pressure of the measuring gas20 mbar overpressure
Max. Permissible temp. Of the measuring gas80 ° C
Analog output
DC output0/4 ··· 20 mA corresponding to xxx ··· ppm
(Going to zero in the error state)