Autocalibration of the DRYCAP sensor optimizes measurement stability in dry environments. During autocalibration the sensor is warmed for a short period (< 1 min) and the sensor capacitance values are evaluated at the elevated temperature. The possible dry end drift is then corrected to correspond to the calibrated values. During autocalibration the values of all available output parameters are locked (showing the latest valid value).
DMP series probes perform autocalibration at 1-hour intervals, and whenever sensor purge is performed. When measuring very dry conditions, the probe performs autocalibration at shorter intervals. A significant change in dew point or temperature may also trigger autocalibration.
Autocalibration is carried out only if several criteria for the measurement environment are fulfilled. This ensures the reliability of the adjustments, and maintains the excellent long term stability that the patented technology offers. These criteria include, for example, a stable enough moisture level in the measured atmosphere. If the conditions are not fulfilled, the autocalibration function is postponed until satisfactory conditions are reached.
Sometimes autocalibration fails to complete successfully due to changes in measurement conditions. This is normal, and is not a problem as autocalibration will be reattempted automatically. However, autocalibration should eventually succeed to maintain the accuracy of the probe.