Vaisala HMP110 - Manual (Page 56)

User's Guide ______________________________________________________________________
54 __________________________________________________________________ M211060EN-E
New filters can be ordered from Vaisala. For available filters, see section
Filter Options on page 14. The order codes of the filters are listed in
section Options and Accessories on page 68.
Calibration Procedure
To calibrate your probe, you need a known stable humidity or
temperature reference, and a way to read the output of the probe (analog
or serial). As a humidity reference you can use, for example, the Vaisala
Humidity Calibrator HMK15.
Refer to chapter Technical Data on page 63 for accuracy specifications of
the probes.
1. Connect the power/signal cable to the probe, but do not power it up
yet.
2. Remove the filter from the probe and place the probe in the
reference environment. For example, you can use a NaCl salt
chamber (75 %RH) as the humidity reference.
3. Wait for 20 – 40 minutes for the reading to stabilize.
4. Power up the probe and wait for one minute.
5. Check the measurement reading, and compare it with the reading
that the reference should produce.
Adjustment Procedure (HMP110 and HMP113)
NOTE If you are adjusting a probe that is in the analog output mode, see section
Terminal Application Settings for Probes in Analog Mode on page 34 for
instructions on how to start the probe in RS-485 mode.
One-Point Adjustment of RH
Measurement (HMP110 and HMP113)
To perform a one-point adjustment to the capacitance measurement of
the HMP110 or HMP113 you need:
- The Vaisala USB cable (Vaisala order code: 219690)
- PC with a terminal application.
- One humidity reference. One-point calibration with a single
< 50 %RH reference will adjust the offset of the measurement. One-
point calibration with a single > 50 %RH reference will adjust the gain
of the measurement.
The procedure below uses the HMK15 Humidity Calibrator. LiCl salt
(11 %RH) is used as the reference point.