Hach-Lange ORBISPHERE Model 51x User Manual - Manual (Page 57)

55
Measurement Menu
Advanced configuration - EC sensor
• Enable pressure sensor : Check as appropriate. See External pressure calibration (optional sensor)
on page 65
• Enable negative concentration : Check as appropriate. See O
3
sensor calibration on page 62
• TPO enable (portable instruments in “Sample mode” measurement only) : Check if TPO
calculation is required.
• TPA enable (portable instruments in “Sample mode” measurement only) : Check if TPA
calculation is required.
• If TPA is enabled, enter the TPA K coefficient if different from the displayed value.
Advanced configuration - TC sensor
• Enable ext. pressure sensor : Check as appropriate. See External pressure calibration (optional
sensor) on page 65
• Enable negative concentration : Check as appropriate.
• Continuous purge during thermal cut off : If thermal cutoff has been enabled (see Measurement
configuration on page 53 ), then check this box to ensure that a continuous purge of the TC sensor
takes place while the measurement session is suspended due to the thermal cutoff temperature
value being exceeded.
Note: To manually set the TC sensor into a continuous purge mode, press the Continuous Purge button
that is available from the Services - Diagnostic - Channel x - Amplifiers menu. See details in the
section entitled
Amplifiers (TC sensor only) on page 102 .
• Offset and slope corrections : Enable correction as appropriate.
• If enabled, the correction values for offset and slope must be entered. These values cannot be
negative.
• Liquid to gas factor : Enable correction as appropriate. If checked, the percentage correction factor
must be entered. This value cannot be negative.
Note: If you believe you need to enable these corrections, it is advisable to contact a Hach Lange Service
Representative first.
Interferences configuration
These options are available to take into account the influence of some components or gases in the
sample during measurement. All available interference corrections are disabled by default.
The following interference corrections are available:
•
For oxygen measurements - CO
2
, H
2
S, Chlorine, Salt, H
2
• For hydrogen measurements - Temperature, H
2
O, He, O
2
• For nitrogen measurements - Temperature, H
2
O, O
2
, H
2
Note: If you believe you need to enable any of the above, it is advisable to contact a Hach Lange Service
Representative first.
Interferences in oxygen measurement
In some applications, like in the beverage industry, there can be high concentrations of carbon
dioxide in the sample. Hach Lange recommends using the CO
2
interference option if a carbon
dioxide concentration of over 1% in gas phase, or 15 ppm in dissolved phase is present.
In the petroleum industry, the detection of oxygen is sometimes hampered by significant
concentrations of hydrogen sulfide in the sample. Hach Lange recommends using the H
2
S
interference option if the hydrogen sulfide concentration exceeds 0.15% in gas phase, or 5 ppm in
dissolved phase. To operate the oxygen sensor in these conditions requires using a different
sensor and electrolyte.
When using this mode your system will experience sensitivity loss of about
50 times higher than the minimum sensitivity for the membrane.
The instrument can also compensate for the presence of high hydrogen levels in the sample.
•
CO2 or H2S : Select CO
2
, H2S or All disabled.
• Chlorinity/Salinity : Select Chlorinity, Salt or All disabled. For chlorinity or salt, it is required to
enter the actual concentration in the sample.
• H2 : Select H
2
enabled or disabled. It is required to enter the interfering gas pressure, which is the
partial pressure of H
2
in the sample.
When enabled, the H
2
interference must be calibrated. See Interference calibration (EC sensor) on
page 64 . A warning pop-up window is displayed to remind the user of this action.