DMT152 is fully calibrated as shipped from the factory. The recommended calibration interval is 2 years. If the transmitter is used in the wet end of the measurement range, calibration should be done every year. Calibration should also be done if there is a reason to believe that the device is not within its accuracy specifications.
You can perform a simple field checking operation by comparing the readings of DMT152 and DM70 handheld dew point meter with a calibrated reference probe. For more information, see Field check using DM70.
If there is need for calibration or adjustment, contact a Vaisala Service Center or your local Vaisala representative.