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3654 Portable H2/N2 Analyzer - Calibrations 39 of 66
Operator Manual
ORBISPHERE
4.2.3 Calibration In H
2
or N
2
at Elevated Pressure
The sensor can be calibrated in pure H
2
or N
2
gas at an elevated pressure. This method
requires an accurate pressure gauge connected to the exit of the flow chamber.
WARNING
Handle H
2
gas with great care. It is extremely flammable and explosive.
When calibrating in gas phase, the flow chamber and sensor head must be dry.To
ensure that the flow chamber and sensor components are dry, remove and dry them with
a clean soft tissue.
1) Set the gas measurement phase to Gaseous and set the calibration medium to
In a liquid or a gaseous sample at known concentration (as detailed in
“Calibration Medium” on page 32).
2) Connect a source of pure H
2
or N
2
gas to the inlet of the flow chamber, as
illustrated in Fig 4-2 on page 37, and adjust the gas flow exiting from the flow
chamber to be in the range of 1 to 5 bar (it is best to use a pressure close to the
application conditions).
3) Press the CAL button. Remember, this
button may have been locked out to
prevent an accidental reset (see “Locking
Out the Instrument’s CAL Button” on
page 32 for details).
4) A brief clearing message [---]
appears.
5) Press CAL again within a 3 second
period. The instrument then displays the
absolute pressure of calibration gas (i.e.
gauge pressure plus atmospheric
pressure).
6) Modify this reading using the Up/Down
Arrow keys until the displayed pressure
agrees with that of the gauge plus
atmospheric pressure.
7) Press CAL again.
If the instrument makes two consecutive
measurements with less than 1%
difference, it calibrates against this
stabilized value. The LCD then displays
the message [CAL] to indicate
calibration has been successfully
completed
If the calibration does not complete, the
LCD displays the message [Err]. The
reason for this calibration error is either
that the measured gas partial pressure is
under 5 mbar, or that a wrong instrument
key was pressed during the calibration
steps.