Bootloader: A program that checks whether the current firmware is valid, then executes the
instrument start-up. The bootloader can be entered by pressing the ‘+’ key on the
front keypad during the first ½ second after power on, and following the prompts.
The bootloader then enables various low level recovery tools, including updating
the main firmware from a USB key.
1.4 Background/Theory
Oxides of Nitrogen (NO
x
) are the product of endothermic reactions within combustion engines and
cause significant environmental pollution.
The main source of NO
x
emissions is from hydrocarbon combustion such as automobile engines or
the burning of coal for power production. These pollutants are harmful to humans and create ozone
gas (O
3
) and acid rain. NO
x
is a major component of the smog found in industrial cities and is harmful
to people with respiratory diseases such as asthma.
1.4.1 Measurement Theory
The measurement of the Oxides of Nitrogen is performed using the gas phase chemiluminescence
method:
Sample air enters the reaction cell via two separate (alternating) paths; the NO and NO
X
channels
NO in the first path reacts with ozone according to the following reaction
NO + O
3
NO
2
* + O
2
Equation 1 – Chemiluminescence reaction for NO
Note: The chemiluminescence reaction is between O
3
and NO only; not NO
2
.
Photons are emitted by the activated NO
2
*
.
The second path travels through a delay loop and the NO
2
to NO converter such that it reaches
the reaction cell after the first path. At which point the NO
x
measurement (the combined
concentration of NO and NO
2
) is taken
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