Calibration
Calibration in Dual Range and Auto Range Mode
Thermo Fisher Scientific
Model 42
i
Trace Level Instruction Manual
4-17
2.
Introduce zero air to the SAMPLE bulkhead and allow the analyzer to
sample zero air until the NO, NO
x
, and NO
2
responses stabilize.
3.
When the responses stabilize, from the Main Menu choose Calibration
>
Cal Prereactor Zero
.
4.
The Prereactor Background screen displays the current prereactor
background and zero concentration.
5.
Press
to set the zero background to zero.
6.
Press
to return to the Run screen.
7.
Repeat Steps 3 through 6, selecting
Cal NO Background
or
Cal NOx
Background
to set the NO and NO
x
backgrounds to zero.
Use the following procedure to calibrate NO channel to the NO
calibration gas.
1.
Disconnect the source of zero air from the SAMPLE bulkhead. In its
place, connect a source of NO calibration gas of about 80% of the low
NO full-scale range.
2.
Allow the analyzer to sample the low NO calibration gas until the NO,
NO
2
, and NO
x
readings stabilize.
3.
When the responses are stabile, from the Main Menu choose
Calibration >
Cal Lo NO Coefficient
.
4.
The Lo NO field displays the current NO concentration.
The Lo NO Span Conc field is where you enter the low NO calibration
gas concentration.
Use
to move the cursor left and right and use
to increment and decrement the numeric character at the cursor.
Calibrate Low NO
