Vaisala SHM40 User Manual
Page 53
Chapter 5 ______________________________________________________________ Maintenance
VAISALA _______________________________________________________________________ 51
CAUTION
If you think the HM40 is not measuring humidity or temperature
correctly, calibration and adjustment is not the first thing to do. Try 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, you must allow it to dry before you can measure.
- Always wait for the measurement to stabilize.
NOTE
For an introduction to calibration, order or download the free calibration
book from Vaisala at the following address:
Calibrating the HMP40S Probe Using
HMK15 Humidity Calibrator
The HMK15 Humidity calibrator allows you to produce known humidity
environments using saturated salt solutions.
When calibrating the HMP40S probe using HMK15, Vaisala
recommends using the special cover set for HMK15 (Vaisala order code
230914). The special cover allows the HMP40S probe to be inserted into
the salt chamber without having to remove the filter.
NOTE
Performing a good calibration takes some time and preparation. Read the
HMK15 User’s Guide before performing your first calibration with the
HMK15.