DST ObservAir Скачать руководство пользователя страница 11

 

 

20 

ObservAir

 Operating Manual 

k.

 

LEDmode:

  Pollution  concentration  data  displayed  using  the  LED 

button in breathing mode. The LED can also be set to display only 
sensor alerts, or be turned off completely. Options are ‘BC’, ‘GAS1’,  
‘GAS2’, ’ALERT’, or ‘OFF’. Default setting is ‘BC’.  

l.

 

LEDra: 

Running  average,  in  seconds,  applied  to  the  pollution 

concentration data displayed using the LED button. Lower running 
average  values  provide  higher  time  resolution  but  the  LED  color 
display  may  fluctuate  due  to  sensor  noise,  while    higher  running 
average  values  provide  a  smoother  display  with  lower  time 
resolution. Default setting is 90 seconds. 

 

m.

 

LEDmaxConc: 

Maximum concentration setting for the LED display. 

Default is 5 

µ

g/m

3

 of BC (default LEDmode setting). 

 

n.

 

LEDtimeout: 

The time duration, in minutes, before which the LED 

display turns off automatically. Default is 20 minutes. 

 

o.

 

maxATN: 

Maximum optical attenuation (ATN). When filter loading 

is above this value, an alarm is triggered. Default is 80. 

 

p.

 

timeZone: 

Time zone in hours relative to GMT. For example, New 

York is represented by “-4” (GMT- 4:00). Default is 0. 

 

q.

 

GPS: 

Optional  GPS  unit  is  logging  when  ‘True’  and  powered  off 

when ‘False’. Default is ‘False’. 

 

 

3.

 

Factors: 

This 

field 

contains 

calibration 

and 

environmental 

compensation factors for each pollutant species monitored onboard the 
ObservAir unit. Most factors in this field are for DST’s internal protocols, 
but those pertinent to the end user are listed below: 

a.

 

MAC: 

Mass  absorption  coefficient  for  BC  determination  (see 

Section 1.1.1). Default value is 12.5 m

2

/g.   

b.

 

FRcal:

 Flow rate calibration factor. Default value is 1.0.  

c.

 

Code1:

 Calibration code for the first optional gas sensor in units of 

nA/ppm.  Each  gas  sensing  cell  has  a  unique  code  from  the 
manufacturer (see Section 1.1.2).  

d.

 

Code2:

  Calibration  code  for  the  second  optional  gas  sensor 

(nA/ppm). 

 

4.

 

colNames: 

Names of the fields logged in the data file as they appear 

on  each  line.  For  the  base  unit  ObservAir,  without  gas  sensing,  the 
following column names will be listed  

a.

 

TS: 

Timestamp in the format: YYYY-MM-DD HH:MM:SS 

b.

 

Iref:

 Reference intensity from the aerosol absorption photometer. 

Value is expressed in terms of the ADC’s raw count. Full scale value 
is 8388607.  

 

 

21 

ObservAir

®

 Operating Manual 

c.

 

Isig:

 Signal intensity from the aerosol absorption photometer. Value 

is  expressed  in  terms  of  the  ADC’s  raw  count.  Full  scale  value  is 
8388607.  

d.

 

ATN: 

Optical attenuation (unitless)  

e.

 

BC:

 Black carbon in 

µ

g/m

3

 

f.

 

T: 

Temperature in ºC.  

g.

 

RH:

 Relative humidity in %.  

h.

 

FR:

 Sample flow rate in ccm.  

i.

 

VBAT:

 Battery voltage in volts. 

 

If the unit has a single gas sensor onboard, the following columns will 
be appended to those above:  

a.

 

GAS1: 

Gas concentration in ppm (except for NO

2

, which is in ppb). 

 

b.

 

Vg_ref1: 

Reference output from electrochemical cell in volts.  

c.

 

Vg_sig1: 

Signal output from electrochemical cell in volts.  

 
If the unit has two gas sensors onboard, the following columns will be 
appended to those above:  

a.

 

GAS2: 

Gas concentration in ppm (except for NO

2

, which is in ppb). 

 

b.

 

Vg_ref2: 

Reference output from electrochemical cell in volts.  

c.

 

Vg_sig2: 

Signal output from electrochemical cell in volts.  

 

3.5.2.

 

Data file  

The ObservAir data is written in comma separated value (csv) format to a 
.txt file. Each line in the file represents a datalogging event, and starts with 
the character “$”. Values are listed in the order provided in the colNames 
field  of  the  corresponding  setting  entry.  Typical  data  output  from  a  base 
model ObservAir (without gas sensing) is shown below. If gas sensors are 
fitted to the unit, the output data will be appended to each line in the order 
listed in the colNames field.  
 

$2020-09-15 23:21:26, 6889274, 7486915, 0.4477415,-0.5281, 37.70047, 32.93088, 99.6, 7.66 
$2020-09-15 23:21:28, 6889416, 7487140, 0.4477730, 0.0924, 37.63485, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:30, 6889638, 7487262, 0.4473400, -1.2549, 37.52956, 32.91753, 100.3, 7.66 
$2020-09-15 23:21:32, 6889808, 7487379, 0.4477415, 1.1772, 37.58144, 32.91753, 100.3, 7.66 
$2020-09-15 23:21:34, 6890005, 7487519, 0.4491062, 4.0048, 37.62112, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:36, 6890185, 7487705, 0.4500246, 2.6575, 37.72641, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:38, 6890353, 7487792, 0.4502516, 0.6841, 37.72336, 32.91753, 100.3, 7.66 
$2020-09-15 23:21:40, 6890537, 7488002, 0.4504004, 0.4360, 37.73556, 32.90417, 100.3, 7.66 
$2020-09-15 23:21:42, 6890700, 7488091, 0.4514685, 3.1003, 37.69894, 32.91753, 100.3, 7.66 
$2020-09-15 23:21:44, 6890863, 7488192, 0.4526644, 3.5079, 37.72641, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:46, 6891009, 7488308, 0.4539852, 3.8455, 37.76455, 32.94423, 100.9, 7.66 
$2020-09-15 23:21:48, 6891181, 7488379, 0.4539719, -0.0397, 37.71267, 32.91753, 99.6, 7.66 
$2020-09-15 23:21:50, 6891322, 7488435, 0.4555502, 4.6042, 37.64859, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:52, 6891469, 7488522, 0.4567795, 3.5648, 37.67300, 32.93088, 100.3, 7.66 
$2020-09-15 23:21:54, 6891617, 7488534, 0.4580860, 3.7495, 37.66232, 32.93088, 100.3, 7.66 
 

Содержание ObservAir

Страница 1: ...rational limits and warnings 11 3 Operating Instructions 13 3 1 Hardware overview 13 3 2 Interactive LED button Sensor display and control 14 3 2 1 Sensor startup 15 3 2 2 Default LED mode Pollutant c...

Страница 2: ...pport WiFi and USB communication protocols and include a 16GB removable SD card for onboard data storage Units may also be supplemented with an LTE LoRa or SigFox communication module and a GPS unit f...

Страница 3: ...collection area is 3 mm in diameter After the first filter the air flow passes through a second reference filter assembly that is identical to the first Since the air is filtered devoid of PM the int...

Страница 4: ...plication Operate the 7 ObservAir Operating Manual ObservAir for 12 to 24 hours in an environment that is free of the analyte gas es and average the voltage differential data collected over the entire...

Страница 5: ...technical specifications are summarized in the tables below All electrochemical cells are sourced from Spec Sensors Gas measurement performance specifications are adapted from data provided by the ma...

Страница 6: ...intervals 2 3 Operational limits and warnings Environmental limits Only operate the ObservAir within the conditions listed in Table 1 Temperature and relative humidity must remain between 5 to 40 C an...

Страница 7: ...nd may result in permanent damage to the unit and or harm to the user Please contact DST Technical Support at info dstech io regarding any problems with your unit that cannot be resolved with the inst...

Страница 8: ...llutants For every new start up event a new data file is created on the SD card txt file and is assigned a filename that contains the sensor s ID number and the start up time date Section 3 5 1 3 2 2...

Страница 9: ...f the ObservAir hold the LED button to cycle through the menu until the first red flash and release The sensor will flash red two more times to confirm that it is shutting down 3 2 6 Sensor alarms and...

Страница 10: ...ront panel 19 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 c...

Страница 11: ...e ADC s raw count Full scale value is 8388607 d ATN Optical attenuation unitless e BC Black carbon in g m3 f T Temperature in C g RH Relative humidity in h FR Sample flow rate in ccm i VBAT Battery vo...

Страница 12: ...tings Figure 12 6 With the Serial Monitor configured ObservAir data is displayed in real time at the time interval set by the user Commands can also be sent to the sensor using the dialog box at the t...

Страница 13: ...8 to 1 2 Set flow rate calibration coefficient Table 7 ObservAir serial commands and descriptions 25 ObservAir Operating Manual 3 7 WiFi connection Provisioning WiFi credentials to the ObservAir allo...

Страница 14: ...1 Zero calibration of pollution sensors Each ObservAir comes with a zero calibration sheet but it is good practice to periodically verify the sensor s baseline performance especially before and after...

Страница 15: ...but clearly the calibration is only as good as the reference measurements collected 4 4 Leak check The ObservAir incorporates a monolithic design architecture that is more robust than traditional ins...

Страница 16: ...loading artifact is not static it depends on the emissions source e g biomass vs diesel atmospheric conditions seasonality and other factors Therefore filter loading correction algorithms should be c...

Страница 17: ...ing can be optimized to meet your needs For example if greater BC measurement resolution is desired at the expense of filter life the flow rate can be increased past the minimum value Conversely flow...

Страница 18: ...exhaust stacks vehicle tailpipes and other pollution sources When sampling emissions directly do not exceed the ObservAir s maximum temperature relative humidity range and pollution concentration rat...

Страница 19: ...If BC measurements are proportionally lower than the reference value then it is also possible but less likely that the ObservAir is leaking Given these potential error modes it is important to valida...

Страница 20: ...38 ObservAir Operating Manual Figure 14 Hard reset using the magnetic cover...

Отзывы: