DST ObservAir Manuale operativo - Pagina 10

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Filter notch aligned with solid white mark.

Notch tip flush with front panel.

Figure 10. Step 3 of filter tab replacement: Push the filter tab into the

sensor until it is fully seated (notch should be flush with front panel) and

tighten the thumbscrew firmly.

It is best to change the aerosol filter while the ObservAir is powered off.

However, if this is not possible or inconvenient, the filter may also be

changed while the sensor is running. In this case, the LED button will flash

red rapidly while the filter is removed to indicate that an error is occurring.

When the filter is replaced and tightened, the LED will go back to normal

breathing mode, indicating current pollutant concentrations. If the LED

flashes red rapidly after replacement, check that the filter tab has been

inserted fully into the sensor and is properly aligned in the slot: The notch

on the tab should be directly above the solid white circle and flush with the

front panel. The sensor will automatically detect the new filter and reset the

ATN to 0. The ATN can also be reset manually (Section 3.2.4).

3.4. Battery charging

Whenever possible, the ObservAir's internal battery should be recharged

using the included micro-USB cable and 2.1A power adapter. The sensor

charges fastest when it is powered off and connected to the 2.1A power

supply: a depleted battery will fully charge in about 5 hours in this

configuration. When the sensor is off and charging, the LED button shines

a solid and turns off when charging is complete. The sensor can also be

plugged into the charger while it is powered on and operating. The battery

will automatically recharge in this state, but at a lower charging current

than when the sensor is powered off. When in normal operation, the LED

button will briefly flash yellow once to indicate that a charging cable has

been successfully connected. The sensor will also trickle charge while

connected to a computer's USB port.

ObservAir Operating Manual

3.5. Data collection from onboard SD card

While the ObservAir is operating, data is written to the onboard SD card in

real time as both a primary means of data collection and a reliable physical

backup when wireless data transmission protocols are implemented. By

default, the ObservAir creates a new data file every time it starts up. Each

file

"DataXXX_YYMMDD_HHhMMm.txt" where XXX represents the ObservAir

unit's ID, followed by the date and time of startup. The SD card also

contains a file called "Settings_DataXXX.txt" (where again XXX represents

the unit's ID) that contains a running log of the sensor's operational

settings. A comprehensive overview of both files' contents is provided below.

3.5.1. Settings file

For each sensor mission, a new entry is appended to the settings file with

the corresponding data file name as the header. Each entry in the settings

file is composed of four sections:

1. Header: The name of the corresponding data file for which the listed

2. Sensor Settings: This field contains information on the sensor's

represents

data

collection

sensor settings apply.

configuration and operational settings. Fields are defined below and

appear in the order listed.

a. SN Serial number.

b. ID: User assigned sensor ID. Default is the unit's SSN.

c. Version: Hardware version number.

d. Firmware: Firmware version number.

e. GAS1: First optional gas sensor mounted onboard.

GAS2: Second optional gas sensor mounted onboard.

g. flowRate: Sample flow rate setting in units of ccm. Default is 100

ccm.

h. samplePeriod: The data collection sample rate in seconds. Default

setting is 2 seconds.

envComp:

DST's

proprietary

algorithms

are

active

('True')

measurements are direct from the sensor(s) and uncompensated

('False'). Default setting is True.

DLPFilter: Digital low pass (DLP) filter is active ('True') or turned off

('False'). The DLP filter decreases measurement noise but increases

the minimum 90% response time from ~2 to 8 seconds when

monitoring BC concentrations. Gas measurement response time is

minimally affected. Default setting is True.

"mission",

and

called

environmental

compensation

pollution

concentration

ObservAir

Operating Manual