Calibration of Oxygen Analyzer
Calibration of most types of oxygen analyzers can be performed manually or by an automatic calibration option. The analyzer controller can be programmed to perform the automatic calibration at specific time intervals, review the calibration results and if they are within programmable parameters, update the controller with the new calibration data.
The procedures are the same for manual or automatic calibrations with the exception that in manual mode, the calibration data has to be manually accepted after the calibration runs.
The calibration procedure is very similar to each type of analyzer, therefore, it is recommended to following the manufacturer’s procedure. The calibration procedures are typically programmer orientated and involve two calibrations gases with the results adjusting the slope of the calibration line within the software.
To Calibrate
*Zero and span gases are connected to the analyzer.
*With the zero-gas flowing through the analyzer, allow the readings to stabilize, then correct the reading to equal the zero gas concentration.
*With the span-gas flowing through the analyzer, allow the readings to stabilize, then correct the reading to equal the span gas concentration.
Sampling System
The sampling system should be periodically checked for proper flows and pressures and filtration and moisture removal.
Low readings are an indication of improper sampling.
Sensor
Zirconia Cell
The inaccurate readings could result from:
Heater temperature thermocouples
Heater itself
Heater temperature controller
Contaminated electrodes
Contaminated zirconia cell
All items should be checked according to the manufacturer’s procedures and diagnostics
Thermoparamagnetic
The inaccurate readings could result from:
Thermistors
Electronic sensing circuit
Auto-zero function
Changing magnetic field
All items should be checked according to the manufacturer’s procedures and diagnostics
Glass Sphere Paramagnetic
The inaccurate readings could result from:
Electronic sensing circuit
Light emitter
Photodiodes
Changing magnetic field
All items should be checked according to the manufacturer’s procedures and diagnostics
Electronics
All analyzers are equipped with extensive self-diagnostics and troubleshooting guides by the manufacturer, which should be followed for any alarms or inaccurate readings.
Author: Mohammed Khaleel
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