beautypg.com

Calibration, 1 calibration with trimmer potentiometers, 1 humidity calibration – Vaisala HMP46 User Manual

Page 12: Calibration with trimmer potentiometers

background image

HMI41 AND PROBES
Operating Manual

M210316EN-A

8

5.

CALIBRATION

The HMI41 indicator and probes are fully calibrated at the factory, so there
should be no immediate need for recalibration. Calibration is recommended
once in a year and always when there is a reason to believe that the
adjustments have changed.

5.1

Calibration with trimmer potentiometers

5.1.1

Humidity calibration

Humidity calibration of the probes is preferably done by adjusting the trimmer
potentiometers. The potentiometers are located under a protective plug. The
potentiometer marked T (temperature) is for factory use only; DO NOT make
any adjustments. To make sure that this potentiometer is not accidentally
touched when adjusting the other two, turn the plastic plug aside without
removing it completely (see Figure 5.1.1).

For adjusting the potentiometers, use a trimming wrench provided with the
probe, or some other suitable tool, e.g. a ceramic 1.5 mm slot screwdriver.

T

W

D

W

D

dry

wet

HMP46

HMP41 &
HMP45

wet

dry

W

D

Figure 5.1.1

Location of trimmer potentiometers

A two point calibration is performed with the HMK15 calibrator or the probe
can be sent to Vaisala. The probes must always be recalibrated when the
sensor is changed.

This manual is related to the following products: