Thermo Scientific 42iQLS, Instruction Manual

Page: 177 / 318

Calibration
Calibration
Thermo Scientific 42iQLS Instruction Manual 4-11
Use the following procedure to set the NO and NO
x
backgrounds to zero.
Both the NO and NO
x
background screens operate the same way.
Note The NO channel should be calibrated first and then calibrate the
NO
x
channel.
▲
For detailed information about the menu parameters and the icons used in
these procedures, see the “
Operation ” chapter.
1. Determine the GPT flow conditions required to meet the dynamic
parameter specifications as indicated in “
Dynamic Parameter
Specifications for Gas Titrator ” earlier in this chapter.
2. Adjust the GPT diluent air and O
3
generator air flows to obtain the
flows determined in “ Dynamic Parameter Specifications for Gas
Titrator ” earlier in this chapter. The total GPT airflow must exceed the
total demand of the analyzer. The 42iQLS requires approximately 100
cc/min of sample flow, and a total GPT airflow of at least 0.5 liters/min
is recommended.
a. Allow the analyzer to sample zero air until the NO, NO
x
, and NO
2
responses stabilize.
b. After the responses have stabilized, from the Home Screen, choose
Calibration>Calibrate Backgrounds>Calibrate NO Background .
The Target NO Concentration button will read 0.000. The
Calculated NO Background button will display the background
needed to make the current NO concentration go to 0.000.
c. Press Calibrate to set the NO reading to zero and save the new
background.
d. Press the Back button to return to the Calibration Backgrounds
screen and repeat this procedure to set the
Calibrate NO
x
Background to zero.
e. Record the stable zero air responses as Z
NO
, Z
NOX
, and Z
NO2
.
3. Adjust the NO flow from the standard NO cylinder to generate a NO
concentration of about 80% of the upper range limit (URL) of the NO
range. The exact NO concentration is calculated from:
F
+
F
+
F
NO
x
F
=
]
[NO
D O NO
STD NO
OUT
Where: