PAR:
Yearly
We usually recommend a yearly PAR calibration, especially if the sensors have been used in high light environments as the UV degrades the filters causing your PAR readings to drift. This PAR calibration is included 1 time a year free with a connectivity and service pack C. The PAR calibration can be done remotely - meaning you don't have to ship all your sensors to us. We ship a golden reference device to you and ask that you to ship it back once the calibration is complete.
- Process explained here: https://help.sigrow.com/par-calibration-via-golden-node-1
CO2:
Every few months
For AirPro+ devices that measure CO2. Calibration can already be done directly by you. We recommend calibration every few months or so due to settling of dust particles inside the CO2 chamber.
- Directions here: https://help.sigrow.com/how-to-calibrate-co2
Air Temperature and Relative Humidity:
Usually not required
We find calibration is not required. The component has a drift of <0.25 per year for RH and a drift of <0.02 per year for temperature.
To check if any devices deviate we recommend the following test: place the sensors together in a sealed box that does not receive UV light for several hours. The temperature and RH readings should even out between sensors.
Please note, depending on the RH of the environment, there may be a difference of max 10% RH between devices that falls within component spec (see below)
Accuracy ±3% @ RH < 80% ±4% @ 80% < RH < 90% ±5% @ 90% < RH < 100%