ToxiRAE Pro CO2 - Operation & Use

[@ikorin]

Hi, why does it show 200ppm inside when 400ppm is the best we can get even outside. Is it a delta ?

[@chriscassidy465]

Igor, the short answer would be that the meter is at the low end of it's range. The ToxiRAE CO2 manual lists the resolution of the meter @100 ppm. The meter reading also changes only in increments of 100 ppm. Outside air does vary around 350-400 ppm. We calibrate the meter @ 5000 ppm, we don't zero calibrate the meter as that would require a separate 100% nitrogen cal bottle and we are mainly interested in dangerous levels of CO2 (IDLH 40,000 ppm). When the meter is turned on I've seen anywhere from 100-400 ppm indicated. To me that is satisfactory as it is in the ballpark for the expected value. Hope this answers your question.

[@ikorin]

Chris Cassidy thank you so much for the explanation. That totally makes sense.