5. Sensors and optical system
ABL90 FLEX reference manual
5-24
Measuring principle of the pCO
2
sensor
The electrode chain (or electrical circuit) set up to measure pCO
2
is illustrated in
the following diagram:
The electrode chain describes an electrical circuit consisting of the following:
Item Part
Description
1
Voltmeter
Measures the voltage potential in the
circuit.
2
pH electrode
Provides electrical connection to the
voltmeter
3
Electrolyte solution
Medium for connection
4
Internal reference electrode
(Ag/AgCl)
Provides electrical connection to the
voltmeter
The potential differences at all the junctions in the electrode chain are known
and constant, except that at the pH-sensitive membrane. (See the section pH
and electrolyte sensors
for a full explanation.)
The potential difference at the pH-sensitive membrane depends on the pH of the
electrolyte solution, which in turn depends on the CO
2
content of the sample.
This is explained in the measuring process below.
Electrode chain
Parts and
description
Electrode chain
potential
Summary of Contents for FLEX ABL90
Page 1: ...ABL90 FLEX reference manual ...
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Page 3: ...ABL90 FLEX reference manual ...
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Page 124: ...3 Wet section ABL90 FLEX reference manual 3 10 ...
Page 125: ...4 Electronics General information 4 2 Electronic boards and components 4 3 ...
Page 216: ...7 Performance characteristics ABL90 FLEX reference manual 7 30 ...
Page 263: ...9 Solutions General information 9 2 Solutions 9 3 Certificate of traceability 9 5 ...
Page 267: ...ABL90 FLEX reference manual 9 Solutions 9 5 Certificate of traceability ...
Page 268: ...9 Solutions ABL90 FLEX reference manual 9 6 ...
Page 269: ...10 1 10 Messages List of analyzer messages 10 2 ...
Page 310: ...10 Troubleshooting updated for software version 2 3 ABL90 FLEX reference manual 10 42 ...
Page 326: ...Appendix Quality control ABL90 FLEX reference manual I 16 ...
Page 327: ...II Appendix Traceability to the primary standards at Radiometer ...
Page 334: ...Appendix Traceability to the primary standards at Radiometer ABL90 FLEX reference manual II 8 ...