ABB EasyLine EL3000, Инструкция по эксплуатации

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134
EL3000
CONTINUOUS GAS ANALYZERS | OI/EL3000-EN REV. D
… 9 Calibration
ZO23 – Checking the reference point and
end point
Checking the end point
We recommend checking the end point approx. 4 weeks after
commissioning.
Further checks of the end-point should be carried out as
required.
Checking the reference point
It is recommended that the reference point is checked once a
year or as required.
Test gases
Reference point (electric zero point)
Clean ambient air;
its oxygen concentration is obtained from the dry air value
and the factor for consideration of the water vapor content.
Example:
Water vapor content at 25 °C and 50 % relative humidity =
1.56 Vol.-% H
2
O

Factor 0.98
Oxygen concentration =
20.93 vol. % O
2
× 0.98 = 20.6 Vol.-% O
2
End position
Test gas with oxygen concentration in the smallest
measurement range (for example, 2 ppm O
2
in N
2
).
Note
The pressure conditions at the reference point and the end point
must be identical.
Caldos27 – Notes for calibration
Calibration methods
• Automatic calibration:
single-point calibration
• Manual calibration:
zero point/end point calibration (factory-set) or single point
calibration
Single-point calibration
Due to the operating principle of the sensor in the Caldos27
analyzer, the zero point and end point do not drift
independently.
Therefore routine calibration of the Caldos27 can be performed
as a so-called single-point calibration using standard gas.
This technique leaves out safety- related measurements.
Depending on the measurement task involved, the zero point
and end point should be checked periodically (recommendation:
once a year).
Standard gas
The ‘Standard gas’ component is always configured as the last
of the maximum five sample components (see
Active
component selection
on page 149) in Caldos27
Single-point calibration with standard gas affects all other
sample components configured in Caldos27
At the factory, a standard gas N
2
with the measured value
10000 rTC is set.
If another standard gas is used during manual calibration, its rTC
set point must be entered as the calibration progresses.
Standard gas rTC set point
N
2
10000 rTC
Air 10070 rTC
Ar 7200 rTC
CO
2
7500 rTC
CH
4
14000 rTC
He 50000 rTC
H
2
60000 rTC
After the standard gas has been changed, the zero point and end
point of the sample components configured in Caldos27 must be
checked and recalibrated, if necessary.