E. Settings
Model AQSync Air Quality Monitoring Station Manual Rev. A-1
28
between two different filter lengths based on the conditions at hand. During the
measurement of stable concentrations, the firmware, by default, computes an average
of the last 36 raw (5-sec) measurements, or 3 minutes of measurements. This provides
smooth and stable readings by averaging out a considerable amount of random noise
to improve the precision. If the filter detects rapid changes in concentration, the filter
reduces the averaging to only 4 samples or 20 seconds to allow the analyzer to respond
more quickly. Two conditions must be simultaneously met to switch to the short filter.
First, the instantaneous concentration must differ from the average in the long filter by
at least 40 ppb. Second, the instantaneous concentration must differ from the average
in the long filter by at least 10% of the average in the long filter. The values cited in this
description are the factory default settings in place when the instrument is shipped:
Change Difference = 40 ppb, Change Percent = 10%, Short Filter = 4 pts (20 s), Long
Filter = 36 pts (3 min).
Via the touchscreen, the lengths of the long and short filter can be changed as well as
the minimum difference and percent difference. Tap on each value and use the popup
keyboard to enter the desired value. Tap “Apply” and then “Save” when all four desired
values are entered. To disable the adaptive filter, set the short filter length to 1, the
difference to 0, and the percent to 0.
E.1.2
NO Calibration and NO
2
Calibration Parameters
The NO
2
/NO/NO
x
instrument is calibrated at the factory, where slope and offset
parameters for NO
2
and NO are entered into the instrument’s memory. These preset
calibration parameters are given in the instrument’s Birth Certificate and recorded on
the
instrument’s calibration sticker. However, the calibration parameters may be
changed by the user if zeroing or calibration of the instrument is carried out. See
Appendix 3 for recommended procedures. Tap on each value and use the popup
keyboard to enter the desired value (in ppb). Be sure to
“Apply” and then “Save”.
E.1.3
Flow Calibration Parameters (Cell, Ozone Flows)
Two different flow measurements are critical to the performance of the instrument: one
is the cell flow rate and the other is the ozone flow rate.
We recommend that you do NOT change the calibration settings for these flow meters
without contacting 2B Technologies to discuss.
E.2
CO
2
Module Settings
The CO
2
instrument in the AQSync is the PP
Systems CO
2
Gas Analyzer, Model SBA-5. Its
manual is available on our website:
https://twobtech.com/pdf/AQSyncInstruments/CO2
_Instrument_PPSystems_SBA-5.pdf
Brief descriptions of the settings are given below.
