Ecotech Serinus 40 - 3. Operation; 3.1 Warm-up; 3.2 Measurement

Operation
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3. Operation
3.1 Warm-up
Once the instrument is turned on it will adjust itself to prepare for monitoring. No measurements are
taken during the warm-up.
The following activities occur during warm-up:
Adjust High Voltage
The high voltage digital pot is adjusted to set the high voltage supply to the PMT for optimal range
and performance.
NO
2
converter is cold warm hot
The instrument progressively increases the temperature of the NO
2
to NO converter until it reaches
the desired temperature of 325°C. When heating from cold the NO
2
converter will take
approximately 60 minutes to reach the desired temperature. When the converter reaches 250°C the
ozone generator will be switched on and analysis of NO/NO
2
/NO
x
will begin.
After this warm-up has completed the instrument will immediately begin taking measurements
(refer to Section 3.2).
3.2 Measurement
The Serinus 40 NO
X
Analyser is a dual channel monitoring instrument which means that it measures
sample air through two different paths. These two paths are used to measure NO (Sample) and NO
X
(Sample Aux) with the NO
2
concentration resulting from a calculation of the difference between the
two. The instrument measures NO and NO
X
in groups of 10 (5 of each), it swaps between the
channels five times each per cycle.
Before each cycle, a background is performed to determine the level of fluorescence without NO
present, thus removing any background noise from the signal.
The sampling procedure follows:
Table 2 – Sample cycle, 5 times per cycle
Instrument State
Duration
Description
Sample Fill
3 sec
Cell fills with NO sample
Sample Measure
3 sec
NO sample is measured
Sample Fill Aux
3 sec
Cell fills with NO
X
sample
Sample Measure Aux
3 sec
NO
X
sample is measured