Calibration
Calibration
4-4
Model 15
i
Instruction Manual
Thermo Fisher Scientific
4.
Press
and choose Calibration >
Cal Background
.
5.
In the Calibrate Zero screen, press
to set the HCl reading to
zero.
If a strip chart recorder is used to obtain a record of the analog output, it is
recommended that the system be adjusted to obtain a zero trace at 5% of
scale. This is to allow observation of zero drift and/or zero noise. Record
the stable zero air response as Z.
Use the following procedure to adjust the span.
1.
Adjust the zero air flow and the HCl flow from the standard HCl
cylinder to provide a diluted HCl concentration of approximately 80%
of the upper range limit (URL) of the analyzer.The total air flow must
exceed the total demand of the analyzer connected to the output
manifold to ensure that no ambient air is pulled into the manifold vent.
The exact HCl concentration is calculated from:
)
F
+
F
(
)
F
x
]
[HCl
(
=
]
[HCl
HCl
D
HCl
STD
OUT
Where:
[HCl]
OUT
= diluted HCl concentration at the output manifold, ppm
[HCl]
STD
= concentration of the undiluted HCl standard, ppm
F
HCl
= flow rate of HCl standard corrected to 25 °C and 760 mmHg, LPM
F
D
= flow rate of dilution air corrected to 25 °C and 760 mmHg, LPM
2.
Allow the instrument to sample this HCl concentration standard until
a stable response is obtained.
3.
From the Main Menu, choose Calibration >
Cal Coef
.
The first line of the display shows the current HCl concentration
reading. The second line of the display shows the HCl range and the
third line is where the HCl concentration is entered.
4.
Enter the HCl calibration gas concentration using the pushbuttons,
and then press
to calibrate the HCl reading to the HCl
calibration gas.
Span Adjust
