ACOEM Met One Instruments GAS-1060, User Manual

Page: 22 / 164

Serinus 60 User Manual 3.0
Page 22
Calibration: The process of adjusting the instrument to ensure
that it is measuring the correct concentration.
Zero Drift: The change in the instruments response to zero air
over a period of continuous unadjusted operation.
Zero Air: Is purified air in which the concentration of NO
2
is
<0.02 ppb with water vapour of less than 10 % RH.
Sufficient purified air can be obtained by passing dry
ambient air through an activated charcoal filter, a
Purafil cartridge and a particulate filter.
External Span Source: Span gas that is delivered via an external accredited
cylinder containing NO in balance with N2 (e.g.
NATA/NIST).
Sample Air: Sample air is defined as the sample before it has
entered the reaction cell, as distinguished from the
exhaust air.
Exhaust Air: Exhaust air is the sample air after it has passed
through the reaction/measurement/detection cell
and is moving towards being expelled from the
instrument.
ID and OD: These are measurements of tubing, ID is the
internal diameter of tubing and OD is the outer
diameter.
Multidrop: A configuration of multiple instruments connected
via the same RS232 cable.
Bootloader: A program that checks whether the current
firmware is valid, 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 enables various low level recovery tools,
including updating the firmware from a USB
memory stick.
PCA: Printed Circuit Assembly. An electronic circuit
mounted on a printed circuit board to perform a
specific electronic function.
Slpm: Standard litres per minute. This is the flow
referenced to standard temperature and pressure
conditions. For the purposes of this manual, all
flows are referenced to 0 °C and 101.3 kpa (1 atm).
1.4 Background/Theory
Nitrogen dioxide (NO
2
) formes quickly from emissions of combustion engines, fossil fuelled power
plants, bacterial action in soil, forest fires, volcanic action and lighting. At high levels NO
2
is a
yellowish gas with a pungent odour. NO
2
is a major chemical pollutant in photochemical smog. NO
2
is
linked with a number of adverse effects on the heart and respiratory system.