Calibration and adjustment overview - HMP1 - HMP3 - HMP4 - HMP5 - HMP7 - HMP8 - HMP9 - HMPX - MMP8 - MMPX - TMP1 - TMPX

HMP Series with MMP8 and TMP1 User Guide

Document code
Document type
User guide

Calibration means comparing the measurement output of the device to a known reference, such as a known environment in a calibration chamber or the output of a reference instrument. Correcting the reading of the device so that it measures accurately is referred to as adjustment.

The probe is fully calibrated and adjusted as shipped from the factory, and a calibration reminder with a 12-month interval is activated in the probe. To maintain the accuracy of the measurement, calibrate and adjust the probe as indicated by the calibration reminder, or as needed. Typical calibration interval is one year, but depending on the application it may be necessary to check the accuracy more frequently.

Vaisala recommends sending the probe regularly to Vaisala for factory calibration. The probe is calibrated and adjusted at multiple points along its measurement range. Factory calibration always includes a traceable calibration certificate and adjustment, if needed.

Factory calibration leads to highest accuracy and lowest uncertainty. After factory calibration the instrument performs as new. For up-to-date information about calibration points and offering, visit

WARNING When returning a product for calibration or repair, make sure it has not been exposed to dangerous contamination, and is safe to handle without special precautions.

It is also possible to calibrate and adjust the probe on the field using the Insight PC software, the Indigo80 handheld indicator, or via an Indigo transmitter that is connected to Insight or Indigo80. You can also modify the probe’s calibration interval and reminder using the above-mentioned tools.

If you think the device is not measuring correctly, calibration and adjustment is not the first thing to do. Check the following first:

  • Make sure nothing is interfering with the measurement: heat sources, temperature differences, or condensation.
  • Check that there is no moisture on the probe. If the sensor has become wet, wait for it to dry.
  • Always wait for the measurement to stabilize.