Thermo 42i, Instruction Manual

Page: 142 / 314

Calibration
Calibration in Dual Range and Auto Range Mode
4-14 Model 42
i
Low Source Instruction Manual Thermo Electron Corporation
2. Verify that the low NO
x
calibration gas concentration is the same as the
low NO calibration gas concentration plus any known NO
2
impurity.
The Lo NO
x
field displays the current NO
x
concentration. The Lo
NO
x
Span Conc field is where you enter the low NO
x
calibration gas
concentration.
Use to move the cursor left and right and use
to increment and decrement the numeric character at the cursor.
3. Press to calculate and save the new low NO
x
coefficient based on
the entered span concentration.
4. Press to return to the Run screen.
Calibrate Low NO
2
Use the following procedure to calibrate the NO
2
channel to the NO
2
calibration gas.
1. Adjust the O
3
generator in the GPT system to generate sufficient O
3
to
produce a decrease in the low NO concentration equivalent to about
80% of the URL of the low NO
2
range. The decrease must not exceed
90% of the low NO concentration determined in the “Calibrate Low
NO
x
” procedure.
2. From the Main Menu choose Calibration > Calibrate LO RNG NO
2
.
The Lo NO
2
field displays the current NO
2
concentration. The Lo
NO
2
Span Conc field is where you enter the Lo NO
2
calibration gas
concentration.
3. Set the low NO
2
calibration gas concentration to reflect the sum of the
NO
2
concentration generated by GPT and any NO
2
impurity.
Use to move the cursor left and right and use
to increment and decrement the numeric character at the cursor.
4. Press to calculate and save the new low NO
2
coefficient based on
the entered span concentration.