UNI-T A37 Carbon Dioxide Monitor User Manual
Introduction
CO2 is a naturally occurring gas that emitted at great levels by human activity and it is one of several greenhouse gases in our atmosphere. CO2 only accounts for 0.03% of the fresh air. If you breathe high concentration COC , you may be at risk of carbon dioxide intoxication. Symptoms of carbon dioxide toxicity include headache, irregular heartbeat, nausea, unconsciousness, or even death.
A37 is a COz Monitor that measures COC concentration, temperature and humidity. This monitor is widely used in homes, shopping malls, offices, vehicles, stations etc.
Please read carefully and follow all warnings and precautions before using the device.
Open box inspection
Open the box and take out the device. Please check whether the following items are deficient or damaged and contact your supplier immediately if they are
- A37 CO2 monitor: 1
- Protective case: 1
- User manual: 1
- USB cable: 1
Safety information
- Check the device and its accessories for any damage or anomaly before Do not use the device if the cover is damaged, or has any other malfunctions.
- Please follow the operation
- Please do not open the device case and modify the internal
- Do not store or use this device in high temperature, high humidity, flammable, explosive and strong electromagnetic
- Charge the monitor when m symbol is
- Regularly use soft cloth and mild detergent to clean the case. Do not use abradant or
- A37 complies with CE
- This monitor has ABC (Automatic Baseline Correction) Do not use this monitor in closed environment where COz concentration remains relatively high.
- Use specified adapter to charge the device. The adapter should comply with UL/FCC safety
Structure
Case 2: LCD screen Os: USB port @: Functional buttons
Symbols
| No | Indication | No | Indication |
| 1 | Audio alarm ON/OFF | 7 | COC concentration |
| 2 | STEL/TWA/MAX
/MIN/AVG modes |
8 | COz concentration grading emoticon |
| 3 | COC calibration | 9 | Relative humidity |
| 4 | Timing shutdown | 10 | Date/time |
| 5 | Battery status | 11 | Temperature |
| 6 | Exit calibration | 12 | Data hold |
Operation instructions
The following table shows the buttons functions in different modes.
| Modes | Functions | Buttons |
| OFF | Long press: turn on/off the monitor |  |
| Long press: enter calibration mode |  |
|
| Measure | Short press: turn on/off the backlight | |
| Short press to switch temperature unit ”C/”F |  |
|
| Long press to turn on/off audio alarm | ||
| Short press: cycle switch between HOLD/MAX/MIN/AVG/TWA/STEL |  |
|
| Long press: reset to zero | ||
| Long press: calibrate the CO2 concentration
(outdoor fresh air) |
 |
|
| Calibration | Short press: increase the value | |
| (double press to enter date/time calibration) | |
|
| Long press: save | |
|
| Short press: decrease the value | |
|
| Short press: previous parameter | |
|
| Long press: exit calibration | |
Operations
COz measurement
Long press @ to turn on the monitor. It takes 120s to stabilize COz concentration. CO2 concentration, ambient temperature, relative humidity will be displayed on the screen. COz concentration value is refreshed every 3 seconds.
Note: if CO2>1000ppm, buzzer goes off with red backlight flashing. The audio alarm’s default setting is OFF, long press @ to turn on the audio alarm.
Concentration grading emoticons
 |
400ppm – 450ppn; |
 |
450ppm – 700ppn; |
 |
700ppm – 1000ppm ; |
 |
1000ppo – 2000pp«i; |
 |
2000ppm – 5000ppm ; |
 |
> 5000ppm |
Data: Short press MODE to cycle switch between HOLD/MAX/MIN/AVG/TWA/STEL values.
| Symbol | Indication |
| Hold | Data hold |
| MAX | Maximum value |
| MIN | Minimum value |
| AVG | Average value |
| TWA | Time weighted average |
| STEL | Short-term exposure limit |
TWA: The average exposure within the workplace to any hazardous contaminant or agent using the baseline of an 8 hour day or 40 hours week work schedule.
STEL: The acceptable exposure limit to a toxic or irritant substance over a short period of time (time-weighted average), usually 15 minutes.
Auto shutdown: The monitor will automatically shut down if there is no operation for 2 hours.
Backlight: Please refer to Operation Instructions-Functional Buttons
Audio alarm: Please refer to Operation Instructions-Functional Buttons
Temperature unit: Please refer to Operation Instructions-Functional Buttons
Battery: Charge the battery when 
is displayed on the screen. It takes 2-3 hours to fully charge the battery.
Calibration
Date/Time
In shutdown state, long press and press twice. Increment and decrement are done throught the buttons and .
Long press the @ button to confirm. Long press @ + @ to exit setting mode.
COz
Note: COC function has been calibrated before delivery. If the value is greatly deviated from the standard, you can calibrate it by either methods below:
Automatic calibrationA37 has the built-in self-correcting ABC (Automatic Baseline Correction) algorithm to automatically adjust the base value.
- Turn on the monitor and leave A37 at a place where there is flowing fresh air for 3 days (powered by the adaptor)
- ABC function will automatically adjust and correct the CO2 standard value.Warnings: ABC function is always on, do not use this monitor in closed environment where COC concentration remains relatively
Manual calibration
- Turn on the monitor, leave it outdoor for 20 minutes
- Long press
until appears on the screen. Calibration takes 10 symbol disappears when calibration is done.symbol disappears when calibration is done.
Note: It is suggested to calibrate the monitor in outdoor environments where there is air flow. Keep device away from animals, plants and human.
Specifications
Technical specification
| Function | Range | Resolution | Accuracy |
| COC | 400-5000 ppm | 1ppm | +(5% of rdg+50ppm) from 400-2000ppm *1 |
| Temperature | -1o.o“c-50.0”C | 0.1”C | +1”C *2 |
| Humidity | o-99%RH | 1%RH | (10%RH 90%RH)
+5%RH @25”C |
- Measure environment: 1atm, ambient temperature and humidity “
- It may be influenced by heat emitted by the adaptor.
General specification
| Specifications | Descriptions |
| Sensor | NDIR principle |
| ABC | Automatic baseline correction |
| Audio alarm | Buzzer |
| Visual alarm | Red backlight |
| Display | LcD screen |
| Low battery indication | |
| Auto power off |
| Backlight | |
| Operating environment | 0’C-50‘C, 0%RH-85%RH |
| Storage environment | -20”C-60”C, 0%RH-95%RH |
| Power supply | Built-in 3.7V DC rechargeable battery |
| Weight | 195g |
| Dimension | 75mm x 55mm x 130mm |
CO2 concentration and effects (only for reference)
| Concentration | Effect |
| 350-450ppm | Fresh air |
| 350-1000ppm | Normal |
| 1000-2000ppm | Turbid air, sleepy |
| 2000-5000ppm | Headache, irregular heartbeat, nausea |
| >5000ppm | Unconsciousness or even death |
Maintenance
- a.The maintenance and service of the device must be implemented by qualified professionals or the designated departments.
- b.Regularly use dry cloth to clean the cover. Do not use the detergent containing solvent composition
- c.To conserve battery, please turn off the device if do not being used for a long time.
UNI-Trend TECHNOLOGY (CHINA) CO., LTD.
No6, Gong Ye Bei 1sr RoadSongshan Lake NAtional High- Tech Industrial Development Zone, Dongguan City, Guangdond Province, China
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