Vaisala HMP228 User Manual
Page 31
HMP228
M210282en-A
Operating Manual
25
4.4.1
Calibration procedure after sensor change
Humidity calibration should be performed in stable conditions using saturated
salt solutions as a reference.
Disconnect the security lock jumper!
4.4.1.1
Using serial commands
•
Leave the calibrator and the transmitter for at least 4 hours in the
same space so that their temperatures have time to equalize. Remove
the filter cap on the transmitter.
•
Insert the sensor head into the calibration hole of the LiCl chamber of
the humidity calibrator.
•
Wait for 30 minutes.
•
Give command FCRH
>FCRH
RH: 11.9 Ref1 ? yy.y
Press any key when ready...
•
The stabilization of the sensor to the reference humidity can be
monitored by giving c
RH: 11.9 Ref1 ? c
RH: 11.5 Ref1 ? c
RH: 11.5 Ref1 ? 11.3
Press any key when ready...
•
Insert the sensor head into the calibration hole of the NaCl chamber of
the humidity calibrator.
•
Wait for 30 minutes.
•
Press any key, enter the second point value and press
RH: 75.5 Ref2 ? yy.y
•
The stabilization of the sensor can be monitored by entering c
instead of the reference value.
4.4.1.2
Using display/keypad commands
•
Leave the calibrator and the transmitter for at least 4 hours in the
same space so that their temperatures have time to equalize. Remove
the filter cap on the transmitter.
•
Insert the sensor head into the calibration hole of the LiCl chamber of
the humidity calibrator.
•
Wait for 30 minutes.