DST ObservAir Скачать руководство пользователя страница 12

 

 

22 

ObservAir

 Operating Manual 

3.6.

 

Computer (serial USB) connection  

 
The  ObservAir  can  stream  data  and  receive  commands  via  a  USB  serial 
connection  to  a  computer.  While  any  serial  monitor  may  be  used  to 
communicate  with  the  sensor,  we  recommend  the  free  and  open  source 
Arduino Serial Monitor for the basic operations outlined in this manual. A 
dedicated computer interface is under development for the ObservAir, and 
will be made available to all users at no cost.  
 

3.6.1.

 

Connecting to Arduino Serial Monitor 

Follow  the  steps  outlined  below  to  connect  the  ObservAir  to  the  serial 
monitor.  
 
1.

 

The  latest  Arduino  IDE  can  be  downloaded  and  installed  from 

https://www.arduino.cc/en/main/software

 

2.

 

With the sensor turned on and operating normally without errors (LED 
button  is  breathing  slowly),  connect  the  ObservAir  to  the  computer 
using the micro USB cable.  

3.

 

Open the Arduino software and select the ObservAir’s serial port from 
the “Tools” menu. For Mac OSX, the port is called 

/dev/cu.usbserial-

DN43xxxx

, as shown in Figure 11 below. Windows does not use port 

naming, and so the port must be found by process of elimination.  

4.

 

In Arduino, open the “Serial Monitor” from the “Tools” menu.  

5.

 

From the pulldown menus at the bottom of the Serial Monitor, select 
the “Both NL & CR” and “115200 baud” settings (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  top  of  the  Serial  Monitor 
window.  

 

 

 

Figure 11. 

Step 3: Select the ObservAir communications port in Arduino 

(Mac OSX shown here).

 

 

 

23 

ObservAir

®

 Operating Manual 

 

 

 

Figure 12. 

Step 5: Screenshot of the Arduino serial monitor. Select “Both 

NL & CR” and “115200 baud” from the pull down menus, as shown. The 

screenshot shows typical live data stream from the ObservAir. 

  

3.6.2.

 

Serial data collection 

Data can be aggregated through serial streaming, Serial data is streamed 
in the same format as it is saved to the SD card (Section 3.5.1). Please note 
that the Arduino Serial Monitor does not have data logging capability. Any 
serial logging software can be configured to save ObservAir data using the 
serial port settings in Table 6.  
 

Port ID 

DN43xxxx 

Baud rate 

115200 

Data bits 

Parity 

None 

Stop bits 

Flow control 

None 

 

Table 6. 

Serial port settings

  

 

3.6.3.

 

Sensor configuration: Serial commands 

Commands can be sent over the Arduino Serial Monitor to configure the 
ObservAir’s various operational settings. Most serial commands share the 
same basic format:  

$cmd$val 

where ‘cmd’ is the name of command, and 

‘val’ is the desired setting value. For example, the command ‘$setFR$100’ 
sets  the  sample  flowrate  to  100ccm.  Table  6  documents  all  available 
commands. All settings are saved to the SD card for each mission.  
 

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...

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