Siemens ULTRAMAT 23 Series Equipment Manual page 28

Description
3.3 Function
Electrochemical oxygen measurement
1
2
3
Figure 3-5
This oxygen sensor operates according to the principle of a fuel cell. The oxygen is converted at
the boundary layer between the cathode and electrolyte. An electron emission current flows
between the lead anode and cathode and via a resistor, where a measured voltage is present.
This measured voltage is proportional to the concentration of oxygen in the sample gas.
The acidic electrolyte used is less influenced by interference influences (particularly CO
and CH
28
Gold cathode
Electrolyte (acetic acid)
Thermistor and load resistor for tempera‐
ture compensation
Operating principle of the electrochemical O
) than other sensor types.
4
4 Signal output
5 Lead anode
6 Oxygen diffusion membrane made of FEP
sensor
2
Equipment Manual, 04/2022, A5E37100388-012
, CO, H ,
2 2
ULTRAMAT 23