Hach-Lange ORBISPHERE Model 51x User Manual - Manual (Page 65)

63
Calibration menu
7.2.3 H
2
sensor calibration
7.3 TC gas sensor calibration
WARNING
Potential Fire and Explosion Hazard. Handle H
2
gas with great care!
H
2
sensor calibration
The recommended method is at known concentration (Direct Value). The gas can be pure H
2
or a
mixture of H
2
with an inert gas (e.g. a mixture of H
2
/N
2
). The known concentration is entered by the user
in the calibration parameter window. The sensor is in contact with the calibration gas in gas phase at
atmospheric pressure.
NOTICE
Make sure the H
2
concentration used for calibration is within the acceptable range for the
membrane. Hach Lange recommends the following calibration gas/inert gas combinations for
calibrating with the following membranes:
Membrane Recommended calibration gas
2956A 1% H
2
/ 99% N
2
2952A 10% H
2
/ 90% N
2
2995A 100% H
2
29015A 100% H
2
Calibration of the measured gas
Start Before initiating a calibration process, the calibration parameters must be
set by pressing on the Modify button. The last calibration parameters are
memorized, so this step can be ignored if the correct parameters are
already set.
Similarly, if only the calibration value has changed, then this can be updated
directly instead of pressing the Modify button.
Note:
When calibration is started, a calibration event is set, and the analog
output and relay are put on hold (if selected below) to avoid unwanted alarms
or potential process problems. This resumes when calibration is finished.
Modify calibration
parameters • Gas Phase : Select liquid or gas (direct calibration only)
• Gas unit type : Partial, fraction or dissolved (dissolved is for
calibration in a liquid only)
• Gas unit : The list of available units depends on unit type selected
above.
• Liquid : Select as appropriate.
• Enter the gas concentration according to the value in the calibration
media.
• Hold during calibration : On by default, this stops any output from the
instrument during the calibration process to avoid sending invalid
information to any connected device.
• Automatic calibration stop : If selected, when the stability criteria is
reached, the calibration process stops automatically.
• Interferences enabled : If selected, this takes into account the influence
of interferences during calibration. By default the same interferences as
during measurement are selected.
Press OK to start calibration