How come your CO2 sensor is measuring below 400 ppm?

How come your CO2 sensor is measuring below 400 ppm?
What is the ideal server room temperature?
Easy environmental monitoring for a server room
Steen Vastgoed and Reporter, a rock-steady duo!
FKT and Reporter: match made in cold room
A weather station with multiple sensors
A power failure detector for your construction site
Combined pressure and temperature measurement
Using a weather station on your construction site
Roof climate research
Sustainable irrigation with a water usage monitoring device
Green roof monitoring
What is the ideal temperature for a cold room?
How to install a weather station
Industrial odour monitoring with a weather station
How groundwater level affects cracks and tears in buildings
4G and solar-powered IoT device: Revolutionizing remote monitoring with Reporter
4 Things to look for in a temperature sensor with API
Housing requirements for a poultry farm: the complete guide
Monitoring heat treatment in cargo containers
How to prevent and detect a barn fire in a pig pen
Poultry monitoring and alarm
Professionally farming mealworms: how to create an ideal growing environment?
Safeguarding poultry from heat stress: how to recognize and prevent it
Sustainable blueberry farming: a case study
Connecting a limit switch to the cloud
A dew point sensor for remote monitoring
The ultimate guide to potato storage monitoring
How KuNa Fish makes fish temperature monitoring a piece of cake
CO2 poisoning in swine and other kinds of pig suffocation
Wind monitoring and wind speed measurement
Halal HACCP: temperature monitoring in a factory
What is dew point?
Why you should monitor relative humidity in curing concrete
Monitoring archive temperature and relative humidity
Weather monitoring: measuring wind at a festival site
Measuring dew point temperature and relative humidity for glue at construction sites
A professional remote monitoring rain gauge with digital measurements
How to tackle the 7 principles of HACCP in restaurants and food companies with simple technology
Sensors
General Use & Installation
Water level sensor to measure the water level in a container or well
A Weather Station with API
Effortless groundwater level monitoring
How is Reporter powered?
How Crodeon helps research companies save time with remote monitoring and data logging
Measuring air quality and insulating performance for Total Value Wall
How Sint-Rembert optimises ventilation and CO2 in schools
Weather Station Maintenance
10 things to consider when buying a professional weather station
Why temperature control is incomplete without remote monitoring

So your CO2 sensor is measuring below 400 ppm? Don’t panic! There is an easy explanation and solution for this problem. The content of this article is based on measurements from the Crodeon CO2 sensor which uses the SCD30 sensing element by Sensirion AG, but it might be relevant for other self-calibrating NDIR sensors as well.

How much ppm is fresh air?

In 2020 the global average of atmospheric CO2 was 412,5ppm, so if your sensor is measuring below 400ppm it probably needs to recalibrate in the correct conditions. The situation is usually caused by the automatic recalibration process of the sensor.

Crodeon has you covered

We advise our customers that the sensor should see 400 ppm outside air regularly, for example during the evening or night phase. By doing this the sensor will recalibrate and consider the lowest measured values of the past period as “fresh air”, or about 400 ppm.

In the datasheet of the SCD30 sensor provided by Sensirion (which can be found on our product page the self-calibrating functionality, also known as the ASC field-calibration algorithm, is explained. This is what it says:

“To work properly SCD30 has to see fresh air on a regular basis. Optimal working conditions are given when the sensor sees fresh air for one hour every day so that ASC can constantly recalibrate.”

Have a look at the graph below. In the data from this Reporter on November 16th we see that it has measured well above 400 ppm for at least three days.

co2 sensor calibration

As a result the sensor calibration algorithm compensated for this. That is why we see measurements below 400 ppm during the following nights. On the 18th of November we advised our customer that the sensor was not getting enough fresh air at night. On the 22nd of November we see in the data that the calibration algorithm adjusted itself to the new circumstances.

Why does my Crodeon CO2 sensor measure below 400 ppm?

As we see in the chart it can happen that your CO2 sensor measure below 400 ppm. In most of the case this is due to environment surrounding the CO2 sensor in combination with the automatic calibration functionality. The sensor will take an average of the lowest measured CO2 levels during a day and will recalibrate itself with it.

When the CO2 sensor doesn’t get enough “fresh” air during consecutive days, it can start measuring below 400 ppm. Placing it regularly for one hour in 400 ppm outside air will help to avoid this.

Sensor error margin

In addition to the calibration process, take into account the error margin of the sensor. In this case the error margin is ±30 ppm + 3% of the measured value. Also notice that the self calibration can take up to 7 days to work at is best, but result should already been seen after 2-3 days.

Measuring physical quantities remains a complex and delicate job. Our job is to help you get reliable measurements and interpret the data in the right way. If you have any more questions on this topic, don’t hesitate to reach out at info@crodeon.com.

Back to blog

Any questions?

Call us at +32474097705 Or use the contact form

  • What is the ideal server room temperature?

    What is the ideal server room temperature?

    Server rooms or data centres have an ideal temperature and humidity range. In this blog we'll be discussing what that range is and why it's so important.

    What is the ideal server room temperature?

    Server rooms or data centres have an ideal temperature and humidity range. In this blog we'll be discussing what that range is and why it's so important.

  • Easy environmental monitoring for a server room

    Easy environmental monitoring for a server room

    The art of sustainable server room management is keeping your room at the highest possible temperature without risking your systems to overheat. This is where server room monitoring comes in,...

    Easy environmental monitoring for a server room

    The art of sustainable server room management is keeping your room at the highest possible temperature without risking your systems to overheat. This is where server room monitoring comes in,...

  • Steen Vastgoed and Reporter, a rock-steady duo!

    Steen Vastgoed and Reporter, a rock-steady duo!

    Steen Vastgoed uses Reporter to continuously monitor the groundwater levels of various project sites. This both in the preliminary phase to a permit and during the execution of the construction...

    Steen Vastgoed and Reporter, a rock-steady duo!

    Steen Vastgoed uses Reporter to continuously monitor the groundwater levels of various project sites. This both in the preliminary phase to a permit and during the execution of the construction...

  • FKT and Reporter: match made in cold room

    FKT and Reporter: match made in cold room

    Jef Ooms of FKT shares his personal experience of using Reporter for several years. Read more to learn how Reporter helps him keep his clients protected against temperature related incidents.

    FKT and Reporter: match made in cold room

    Jef Ooms of FKT shares his personal experience of using Reporter for several years. Read more to learn how Reporter helps him keep his clients protected against temperature related incidents.

1 of 4
  • Live online demo

    Sign up for a free account on the Crodeon Dashboard a watch a real live working demo.

    Watch the demo 
  • Talk to sales

    Schedule an appointment with Jonathan, our Sales Manager, for more information about this solution.

    Schedule a call 
  • Contact us

    For partnerships, distribution, or any other question, don't hesistate to contact us!

    Contact us