Calibration commands, Crh relative humidity calibration, Relative humidity calibration – Vaisala HMP230 User Manual
Page 90: Fcrh, Relative humidity calibration after sensor change
HMP230 SERIES
Appendix 1: Serial commands
M210225en-B
84
2.
CALIBRATION COMMANDS
CRH
Relative humidity calibration
Disconnect the security lock jumper!
CRH <cr>
With this command the transmitters can be calibrated against a reference. A
one-point calibration can be done against an accurate transfer standard in the
field and a two-point calibration using saturated salt solutions in controlled
conditions. A two-point calibration is performed as follows:
>CRH <cr>
RH
:
12.00
Ref1 ?
11.3 <cr>
Press any key when ready ...
RH
:
76.00
Ref2 ?
75.5 <cr>
In one-point offset correction, the Ref2 prompt is acknowledged with <cr>:
>CRH <cr>
RH
:
12.80
Ref1 ?
11.3 <cr>
Press any key when ready ...
RH
:
75.50
Ref2 ?
<cr>
If the stabilization of the sensor to the humidity in the calibrator needs to be
monitored, the measurement output can be repeated by giving command c<cr>
at Ref1 and Ref2:
>CRH <cr>
RH
:
12.00
Ref1 ?
c <cr>
RH
:
11.70
Ref1 ?
c <cr>
RH
:
11.50
Ref1 ?
11.3 <cr>
Press any key when ready ...
RH
:
76.00
Ref2 ?
75.5 <cr>
FCRH
Relative humidity calibration after sensor change
Disconnect the security lock jumper!
FCRH <cr>
After humidity sensor change the transmitter must be calibrated using this
command and the calibration must be done at two reference points. The cali-
bration is performed as follows:
>FCRH <cr>
RH
:
1.90
Ref1 ?
11.3 <cr>
Press any key when ready ...
RH
:
76.30
Ref2 ?
74.9 <cr>