Vaisala HMP240 - Manual (Page 54)

HMP240
User's Guide
M210300en
52
6.2.2 Two point temperature calibration
6.2.2.1 With serial commands
• Leave the reference instrument and the transmitter for at
least 4 hours in the same space so that their temperatures
have time to equalize. Remove the filter cap prior to
calibration.
Disconnect the security lock jumper!
• Check the transmitter against the reference.
• For the humidity sensor head: give command CT ,
enter the first point value and press :
>CT
T : xx.x Ref1 ? yy.y
Press any key when ready
• If you want to see how the sensor stabilizes to the refer-
ence temperature, enter c instead of the first refer-
ence:
T : 0.90 Ref1 ? c
T : 0.55 Ref1 ? c
T : 0.55 Ref1 ? 0.0
Press any key when ready...
• For the additional temperature sensor head: give command
CTA , enter the first point value and press :
>CTA
Ta: -20.07 Ref1 ? -20.08
Press any key when ready...
• Change the temperature and check the transmitter again
against the reference.
• Check that the reading corresponds to the reading of the
reference instrument. If not, adjust the second point.
• Press any key, enter the second point value and press .
T (or Ta) : xx.x Ref2 ? yy.y
• The stabilization of the sensor can be monitored by
entering c instead of the reference value.