The sensor purge feature is available in the DMP74B and DMP74C probes. Sensor purge is an automatic procedure in which the sensor is dried. This improves sensor response time when installing the probe from an ambient to dry gas. Together with autocalibration it will also ensure the best measurement accuracy and long-term stability.
By default, sensor purge is turned on automatically in DM70, and it is recommended not to turn it off. The purge is performed if humidity changes significantly or quickly and if the dew point is low enough. If the power is continuously turned on in DM70, or if DM70 has been left in logging mode (display on or off), the automatic sensor purge will be performed at a set interval (the default is 24 hours).
If automatic sensor purge has been turned off, the purge should be started manually if it has not been performed during the last 24 hours. You can start sensor purge manually in the Functions menu of the MI70 indicator.
For more information on sensor purge, see DM70 User Guide (M010091EN).