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Emerson Process Management GmbH & Co. OHG3-14
X-STREAM X2
Short Form Manual
HASX2E-SFM-HS
02/2012
3.7 Calibrating the Analyzer
Note!
To achieve best and proper measuring results
it is recommended to perform zero and span
calibrations on a regular weekly basis.
Also a zero calibration must always precede
a span calibration!
Zero calibration
Nitrogen (N2) or any other suitable neutral gas
is supplied to the gas path. The concentration
of the component of interest is declared to be
"zero" and so the measured signal during zero
calibrations is declared to be 0.
Span calibration
Span gases with concentrations of 80 % to
110 % of the upper measuring range limit is
supplied to the gas path (lower concentrati-
ons are acceptable, but inuence accuracy of
measurements if later sample gas concentra-
tions are higher). The contained concentration
of the component of interest is setup as set
point, and the measured value during span
calibration is then declared to correspond to
that concentration.
Note!
If the current concentration is known, ambient
air may be used to span calibrate %-Oxygen
channels.
X-STREAM gas analyzers support several
calibration procedures:
Manual calibration
Typically a calibration procedure is carried out
manually by supplying the gases sequentially
by hand and activating the procedures via
front panel keys.The operator has to take
care to consider purge times and supply the
proper gases in correct order.
It is the operators responsibility to not perform
a span calibration without a preceding zero
calibration!
Advanced calibration
Advanced calibration is a more comfortable
variation of manual calibration, providing ONE
KEY calibrations supported by internal and/or
external valves. The analyzer automatically
supplies the right gas and considers purge
times.
Remote calibration
Remote calibrations may be activated by
means of digital inputs or Modbus commands.
Calibrations activated via digital inputs re-
quire either internal or external valves to be
installed. Modbus supports both calibrations
with or without valves as well as calibration
sequences.
Unattended automatic calibration
Unattended automatic calibrations are activa-
ted utilizing the analyzer software time interval
setting:
After a specied time interval has elapsed,
the analyzer automatically carries out valve
supported zero or span calibrations.
The main advantage is that no user interaction
is required to start a calibration or during cali-
brations: The analyzer automatically supplies
the right gas, considers purge times and, that
a span calibration has to be preceded by a
zero calibration.
The following sections describe
how to carry out manual cali-
brations.
For information about other
calibration procedures see the
X-STREAM X2 instruction ma-
nual.
3.7 Calibrating the Analyzer