During thermohygrograph calibration, the instrument is placed in a controlled environment with known temperature and humidity levels. The instrument's readings are compared to the reference values, and adjustments are made if necessary to ensure accurate measurement. Calibration certificates are provided to document the calibration process and results, providing traceability and peace of mind for the customers.

The frequency of calibration depends on several factors, including the industry, application, and the frequency of use. Typically, thermohygrographs should be calibrated at least once a year, but some applications may require more frequent calibration.