This is my favorite brand of meter, the one I have literally used my entire professional career as a safety engineer and emergency responder. I am not naming the brand as I do not want to cause them any issues, but just understand this, ALL brands will have this level of accuracy. Most users of these instruments never really think about how accurate they are. Most just assume they are highly accurate. As my previous posts discussed the limitation of the LEL sensors, this post I want to point out a limitation of the Oxygen sensor.
XXXXXXXX oxygen sensors for XXXXXXXX 4X/4XR/5X detectors offer 0–30% Vol Oxygen range, 0.1% resolution, and <10s typical response time (t90). These sensors feature >4 year lifespan, ±10% accuracy (depending on model), and ASIC technology for high stability and low pressure sensitivity.
Did you know your O2 sensor had a +- 10% accuracy. So when the meter is reading 19.6%, you very well could be at 17.64% or 21.56%.
Some meter manufacturers claim their O2 sensors have an accuracy range of 1.0 – 2.0% which is REALLY good. Should our chose of meter consider the accuracy limitations? I would think so. One has an accruacy of +-10% and one has an accuracy of +-1-2%. That is a huge difference.