CO₂ sensor Forum Discussions

Actual Measurement Result
When CO2 was injected into the closed space with the PAS CO2 Sensor, the CO2 concentration in the GUI increased immediately.
16:10:49(JST)/500ppm ⇒ 16:10:59(JST)/1500ppm
After that, it stabilizes at 32618ppm.
Leave PAS CO2 from enclosed space to open space (≈400ppm) at 16:16:39(JST)
16:21:49(JST)/32765ppm
16:21:59(JST)/32671ppm
16:22:09(JST)/18915ppm
16:22:19(JST)/7576ppmm

16:31:39(JST)/436ppm, Finally back to the CO2 concentration of the open space. Why does it take so long, 15 minutes, to get back to normal?

Translated with www.DeepL.com/Translator (free version)

I am using PAS CO2 sensor in single shot mode. Power up sequence: +3.3V , then +12V, then wait minimum 1s.

PWM_DIS connected to 3.3V, PSEL connected to GND. 

I trigger a measurement every minute, enabling ABOC in the field BOC_CFG (register MEAS_CFG). [write 0x05 into MEAS_CFG]

Then I wait minimum 2 seconds, and afterwards I read out the measurement value. Outdoor (country side, clean air) I get values around 800ppm. Whether I enable or not the ABOC, the measured values seem to be the same. 

Am I missing something? 

In the end I assumed there is a sensor offset of ~400ppm, and I subtracted it from the measured values. Is this a valid approach?  

The effect of voltage input to the accuracy of CO2 sensor?

- I want to know about the effect of input voltage to the accuracy of CO2 sensor. As in the CO2 datasheet, 12V supply voltage is Min = 9.6V and Max = 14.4V. Will accuracy of CO2 sensor change when the input voltage varies in this range?

How frequent should we input pressure compensation?

We have a pressure sensor in their system, so customer can reflect the value from their pressure sensor into CO2 sensor. Thus, we want to know how frequent should (can) we input the pressure value to CO2 sensor. Is it OK to input the CO2 compensation value every cycle?

If customer stop the sensor in condition of humidity larger 85% (when maintenance for example), then turn back to operate after humidity < 85%. Will this affect CO2 sensor value/operation?