1. Our T/RH sensors are digitally calibrated by our supplier, Sensirion. Their calibration is traceable to a NIST standard but we do NOT supply a calibration certificate. They cannot be re-calibrated. Most of our T/RH sensors cost less than a trip to the calibration lab making re-calibration a poor economic choice.
2. Temperature is very stable over time and should never require calibration although periodic accuracy verification should be done as your process requires.
3. RH accuracy depends highly on the VOCs in the environment the sensor is used in. Exposure to liquid alcohol will, for example, cause an immediate shift of up to 10% RH. If you are uncertain about the effects of the VOCs in your specific operating environment you should verify RH accuracy frequently until you have quantified the impact the VOCs in your environment will have on RH sensor accuracy.
4. RH sensor accuracy should be checked periodically as your process requires.
5. RH sensor shift caused by VOCs is reversible. The VOCs contaminate the hygroscopic polymer that is used in the RH sensing element. The VOC contaminants can be "baked off" by baking the RH sensor at 100C for 12 hours. The problem is the ABS plastics used in our sensor enclosures can only withstand 65C before they start to soften and deform. For that reason we designed our S-2 sensor with the A-1 user replaceable plug in T/RH probes.
Bottom line? Temperature should be highly stable over time and RH stability is very much subject to the VOCs the RH sensors are exposed to. If RH accuracy matters to you then use our S-2 sensors with the A-1 probes such that you can either periodically replace the probes or you can restore their accuracy by baking just the tip of the A-1 probe at 100C for 12 hours.
2. Temperature is very stable over time and should never require calibration although periodic accuracy verification should be done as your process requires.
3. RH accuracy depends highly on the VOCs in the environment the sensor is used in. Exposure to liquid alcohol will, for example, cause an immediate shift of up to 10% RH. If you are uncertain about the effects of the VOCs in your specific operating environment you should verify RH accuracy frequently until you have quantified the impact the VOCs in your environment will have on RH sensor accuracy.
4. RH sensor accuracy should be checked periodically as your process requires.
5. RH sensor shift caused by VOCs is reversible. The VOCs contaminate the hygroscopic polymer that is used in the RH sensing element. The VOC contaminants can be "baked off" by baking the RH sensor at 100C for 12 hours. The problem is the ABS plastics used in our sensor enclosures can only withstand 65C before they start to soften and deform. For that reason we designed our S-2 sensor with the A-1 user replaceable plug in T/RH probes.
Bottom line? Temperature should be highly stable over time and RH stability is very much subject to the VOCs the RH sensors are exposed to. If RH accuracy matters to you then use our S-2 sensors with the A-1 probes such that you can either periodically replace the probes or you can restore their accuracy by baking just the tip of the A-1 probe at 100C for 12 hours.
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