Hach-Lange ORBISPHERE Model 51x User Manual - Manual (Page 58)

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Measurement Menu
Interferences in hydrogen measurement
The presence of oxygen in the sample can have an effect on the hydrogen sensor to varying
degrees, depending on the membrane being used. The oxygen correction option enables the
instrument to correct for this condition.
•
Temperature compensation : If there is a significant fluctuation in the sample temperature
enable temperature compensation to reduce the influence of these temperature fluctuations.
• Interfering H2O : This only applies to measurements taken in 100% humid gases or in traces of
dissolved gas in water. It allows a correction to the slope and temperature coefficients calculated
during calibration.
• Interfering O2 : If the sample is known to contain oxygen, check this box.
The instrument can also compensate for the presence of helium in the sample.
•
Temperature compensation : As described above.
• Interfering H2O : As described above
• Interfering He constant : If helium is the interfering gas enable this option to allow the instrument
to correct for the presence of helium in the sample.
• Interfering He : If the sample contains a known concentration of helium, check this box and enter
the concentration percentage in the box provided.
Interferences in nitrogen measurement
The presence of oxygen in the sample affects the nitrogen sensor. Oxygen produces about three
times the effect of an equivalent amount of nitrogen in a TC sensor causing a comparably erroneous
displayed value. For example, a properly calibrated nitrogen sensor, placed in air having 80%
nitrogen and 20% oxygen would, uncorrected, display approximately 140% nitrogen (80% + 3*20%).
In the beverage application there is often little oxygen present, and this interference can be ignored.
However, if this simplification cannot be made use this oxygen correction option to enable the
instrument to correct for this condition.
•
Temperature compensation : If there is a significant fluctuation in the sample temperature
enable temperature compensation to reduce the influence of these temperature fluctuations.
• Interfering H2O : This only applies to measurements taken in 100% humid gases or in traces of
dissolved gas in water. It allows a correction to the slope and temperature coefficients calculated
during calibration.
• Interfering O2 : If the sample is known to contain oxygen, check this box.
The instrument can also compensate for the presence of high hydrogen levels in the sample.
•
Temperature compensation : As described above
• Interfering H2O : As described above
• Interfering H2 : If the sample is known to contain hydrogen, check this box.