The HM70 is fully calibrated as shipped from the factory. Adjustment should only be done if there is a reason to believe that the device is not
within the accuracy specifications. However, if HM70 is used as a reference instrument in humidity measurements, the humidity recalibration is recommended every year.
| Check when the latest adjustment was made from the Last adjustment date view or from the Device information view (see Device information). |
It is recommended to send the device to Vaisala for calibration: for contact information, see Technical support. Alternatively, you can calibrate and adjust HM70 by following the instructions given in this chapter.
When using Vaisala Humidity Calibrator HMK15, use the adapter fitting (13.5 mm hole) with HMP76 and HMP77 probes. The HMP75 probe does not need the adapter fitting. If the chemical purge option is available, always perform it before calibration (for instructions, see Chemical purge (optional)). Before starting the adjustment mode, remove the screw that covers the calibration button. See Figure 1 for the location of the button.